Ackermann Pure Pursuit

Package Summary

Version	0.1.0
License	Apache 2.0
Build type	AMENT_CMAKE
Use	RECOMMENDED

Repository Summary

Description
Checkout URI	https://github.com/WATonomous/wato_monorepo.git
VCS Type	git
VCS Version	main
Last Updated	2026-10-15
Dev Status	DEVELOPED
Released	UNRELEASED
Contributing	Help Wanted (-) Good First Issues (-) Pull Requests to Review (-)

Package Description

Pure pursuit controller for ackermann vehicles

Maintainers

WATonomous

Authors

No additional authors.

Ackermann Pure Pursuit

ROS2 lifecycle node that tracks a trajectory using the pure pursuit algorithm, publishing Ackermann drive commands for vehicle steering and speed control.

Overview

The pure pursuit node receives a planned trajectory, transforms each waypoint into the vehicle’s rear-axle reference frame (once per cycle), selects a lookahead point, and computes the steering angle and speed via the pure pursuit geometric algorithm. The lookahead distance is adapted to speed and path curvature, speed is limited by a lateral-acceleration budget, and the steering/speed commands are rate-limited for smoothness. Each cycle it measures cross-track and heading error and, if either exceeds a tunable threshold for a sustained window, raises a disengage recommendation in its ControllerStatus telemetry. This is advisory only: the controller keeps tracking normally and does not alter its command, yield the mux, or talk to the OSCC layer — acting on the recommendation is left to a higher-level supervisor. It publishes an idle signal and standby Ackermann commands when no valid trajectory is available, the trajectory has gone stale, or the behaviour tree requests standby.

Current Status: Adaptive pure pursuit controller with rear-axle geometry, TF-based wheelbase measurement, model-aware variable lookahead, curvature/accel-limited speed control, command-rate limiting, an optional low-speed Stanley cross-track blend, a debounced disengage monitor, and live-reconfigurable parameters.

ROS Interface

Subscribed Topics

Topic	Type	Description
`trajectory`	`wato_trajectory_msgs/Trajectory`	Planned trajectory from the freeroam planner
`execute_behaviour`	`behaviour_msgs/ExecuteBehaviour`	Requested behaviour from the behaviour tree

Published Topics

Topic	Type	Description
`/action/ackermann`	`ackermann_msgs/AckermannDriveStamped`	Steering angle and speed command
`/action/is_idle`	`std_msgs/Bool`	`true` when idle or in standby (the disengage monitor does not raise this)
`controller_status`	`wato_trajectory_msgs/ControllerStatus`	Per-cycle tracking error, effective lookahead, path curvature, commands, and disengage state/reason

Also subscribes to odom (nav_msgs/Odometry) for the current longitudinal speed used by the adaptive lookahead and speed scheduling.

Configuration

Parameters are loaded from config/params.yaml under the namespace action/pure_pursuit_node/ros__parameters.

Parameters are read once in on_configure. To change them at runtime, transition the lifecycle node back through cleanup → configure (which reloads config/params.yaml), as with the other action nodes.

Topics / frames

Parameter	Type	Default	Description
`controller_status_topic`	string	`"controller_status"`	Topic for the `ControllerStatus` telemetry
`base_frame`	string	`"base_footprint"`	Frame stamped on published Ackermann commands
`rear_axle_frame`	string	`"rear_axle"`	Frame the pure-pursuit geometry and tracking error are computed in; also one end of the TF wheelbase measurement
`front_axle_frame`	string	`"front_axle"`	Other end of the TF wheelbase measurement
`standby_msg`	string	`"standby"`	Behaviour string that triggers standby output

Adaptive lookahead

Parameter	Type	Default	Description
`lookahead_distance`	double	`5.0`	Maximum lookahead distance (m)
`min_lookahead_distance`	double	`2.0`	Minimum lookahead distance (m)
`lookahead_time`	double	`1.5`	Time-headway: `ld = lookahead_time · speed`, clamped to min/max (s)
`curvature_lookahead_gain`	double	`2.0`	Shrinks lookahead in curves: `ld_eff = ld / (1 + gain·\|κ\|)`
`speed_lookahead_distance`	double	`1.0`	Minimum distance ahead used to sample target speed (m)
`speed_lookahead_time`	double	`2.0`	Time-headway for the (decoupled, longer) speed sample horizon (s)

Steering & speed

Parameter	Type	Default	Description
`steering_angle_gain`	double	`1.0`	Gain on the pure-pursuit steering output
`max_steering_angle`	double	`0.5`	Maximum steering magnitude (rad)
`max_steering_rate`	double	`1.0`	Steering slew-rate limit (rad/s)
`max_speed` / `min_speed`	double	`5.0` / `0.0`	Commanded speed bounds while tracking (m/s)
`max_lateral_accel`	double	`2.5`	Cornering-speed budget: `v ≤ sqrt(a_lat/\|κ\|)` (m/s²)
`max_accel` / `max_decel`	double	`1.5` / `3.0`	Command accel/decel slew limits (m/s²)

Low-speed cross-track blend (Stanley)

Parameter	Type	Default	Description
`enable_stanley_blend`	bool	`false`	Blend a cross-track feedback term into steering at low speed
`stanley_gain`	double	`0.5`	Cross-track feedback gain `k_e`
`stanley_softening`	double	`1.0`	Softening constant `k_soft` (avoids blow-up near zero speed)
`stanley_speed_threshold`	double	`2.0`	Blend weight ramps from 1 (at 0) to 0 at this speed (m/s)

Disengage monitor

Parameter	Type	Default	Description
`enable_disengage`	bool	`true`	Enable the tracking-threshold disengage monitor
`max_cross_track_error`	double	`1.5`	Cross-track error that (sustained) trips a disengage (m)
`max_heading_error`	double	`0.6`	Heading error that (sustained) trips a disengage (rad)
`disengage_debounce_sec`	double	`0.5`	How long the error must be exceeded before tripping (s)
`disengage_latch`	bool	`false`	`true` = stay disengaged until reconfigured; `false` = auto-recover
`disengage_speed`	double	`0.0`	Safe speed commanded when no valid lookahead point exists (m/s)

Standby / misc

Parameter	Type	Default	Description
`standby_speed`	double	`-0.5`	Speed commanded during standby (m/s)
`standby_steering`	double	`0.0`	Steering commanded during standby (rad)
`control_rate_hz`	double	`20.0`	Control publish rate (Hz)
`wheelbase_fallback`	double	`2.5667`	Fallback wheelbase if the TF lookup fails (m)
`idle_timeout_sec`	double	`2.0`	Time since last trajectory before declaring idle (s)
`invert_steering`	bool	`true`	Invert steering sign — `true` means positive angle = clockwise
`disable_standby`	bool	`false`	Bypass standby and track even when `standby_msg` is received

Algorithm Details

File truncated at 100 lines see the full file

CHANGELOG

No CHANGELOG found.

Package Dependencies

Deps	Name
	ament_cmake
	wato_test
	rclcpp
	rclcpp_lifecycle
	behaviour_msgs
	geometry_msgs
	nav_msgs
	std_msgs
	ackermann_msgs
	tf2
	tf2_ros
	tf2_geometry_msgs
	wato_trajectory_msgs

System Dependencies

No direct system dependencies.

Dependant Packages

Name	Deps
action_bringup

Launch files

No launch files found

Messages

No message files found.

Services

No service files found

Plugins

No plugins found.

Recent questions tagged `ackermann_pure_pursuit` at Robotics Stack Exchange

ackermann_pure_pursuit package from wato_monorepo repo

ackermann_pure_pursuit action_bringup freeroam_planner global_planning lattice_planning lattice_planning_markers lattice_planning_msgs model_predictive_control mpc_controller osqp_eigen_vendor trajectory_planner wato_trajectory_msgs infrastructure_bringup tf_static_relay vision_msgs_markers wato_lifecycle_manager ackermann_mux camera_calib lidar_imu_calib lidar_lidar_calib can_state_estimator dummy_ackermann eve_description interfacing_bringup joystick_interfacing lidar_aggregator oscc_interfacing oscc_mux pid_control pid_msgs roscco_msg sensor_interfacing topic_healthchecker attribute_assigner bevfusion cuda_bevfusion_vendor depth_estimation feature_extraction patchworkpp patchworkpp_vendor perception_bringup perception_utils spatial_association bytetrack_cpp_vendor track_viz_2d tracking traffic_light_detection carla_bringup carla_common carla_control carla_lifecycle carla_localization carla_msgs carla_perception carla_pygame carla_ros_bridge carla_sample_description carla_scenarios carla_teleop simulation_bringup wato_test behaviortree_ros2_vendor behaviour behaviour_markers behaviour_msgs costmap costmap_markers costmap_msgs eidos eidos_msgs eidos_tools eidos_transform lanelet_markers lanelet_msgs lidar_localization prediction world_model world_model_markers world_model_msgs world_modeling_bringup

ROS Distro
jazzy

Package Summary

Version	0.1.0
License	Apache 2.0
Build type	AMENT_CMAKE
Use	RECOMMENDED

Repository Summary

Description
Checkout URI	https://github.com/WATonomous/wato_monorepo.git
VCS Type	git
VCS Version	main
Last Updated	2026-10-15
Dev Status	DEVELOPED
Released	UNRELEASED
Contributing	Help Wanted (-) Good First Issues (-) Pull Requests to Review (-)

Package Description

Pure pursuit controller for ackermann vehicles

Maintainers

WATonomous

Authors

No additional authors.

Ackermann Pure Pursuit

ROS2 lifecycle node that tracks a trajectory using the pure pursuit algorithm, publishing Ackermann drive commands for vehicle steering and speed control.

Overview

The pure pursuit node receives a planned trajectory, transforms each waypoint into the vehicle’s rear-axle reference frame (once per cycle), selects a lookahead point, and computes the steering angle and speed via the pure pursuit geometric algorithm. The lookahead distance is adapted to speed and path curvature, speed is limited by a lateral-acceleration budget, and the steering/speed commands are rate-limited for smoothness. Each cycle it measures cross-track and heading error and, if either exceeds a tunable threshold for a sustained window, raises a disengage recommendation in its ControllerStatus telemetry. This is advisory only: the controller keeps tracking normally and does not alter its command, yield the mux, or talk to the OSCC layer — acting on the recommendation is left to a higher-level supervisor. It publishes an idle signal and standby Ackermann commands when no valid trajectory is available, the trajectory has gone stale, or the behaviour tree requests standby.

Current Status: Adaptive pure pursuit controller with rear-axle geometry, TF-based wheelbase measurement, model-aware variable lookahead, curvature/accel-limited speed control, command-rate limiting, an optional low-speed Stanley cross-track blend, a debounced disengage monitor, and live-reconfigurable parameters.

ROS Interface

Subscribed Topics

Topic	Type	Description
`trajectory`	`wato_trajectory_msgs/Trajectory`	Planned trajectory from the freeroam planner
`execute_behaviour`	`behaviour_msgs/ExecuteBehaviour`	Requested behaviour from the behaviour tree

Published Topics

Topic	Type	Description
`/action/ackermann`	`ackermann_msgs/AckermannDriveStamped`	Steering angle and speed command
`/action/is_idle`	`std_msgs/Bool`	`true` when idle or in standby (the disengage monitor does not raise this)
`controller_status`	`wato_trajectory_msgs/ControllerStatus`	Per-cycle tracking error, effective lookahead, path curvature, commands, and disengage state/reason

Also subscribes to odom (nav_msgs/Odometry) for the current longitudinal speed used by the adaptive lookahead and speed scheduling.

Configuration

Parameters are loaded from config/params.yaml under the namespace action/pure_pursuit_node/ros__parameters.

Parameters are read once in on_configure. To change them at runtime, transition the lifecycle node back through cleanup → configure (which reloads config/params.yaml), as with the other action nodes.

Topics / frames

Parameter	Type	Default	Description
`controller_status_topic`	string	`"controller_status"`	Topic for the `ControllerStatus` telemetry
`base_frame`	string	`"base_footprint"`	Frame stamped on published Ackermann commands
`rear_axle_frame`	string	`"rear_axle"`	Frame the pure-pursuit geometry and tracking error are computed in; also one end of the TF wheelbase measurement
`front_axle_frame`	string	`"front_axle"`	Other end of the TF wheelbase measurement
`standby_msg`	string	`"standby"`	Behaviour string that triggers standby output

Adaptive lookahead

Parameter	Type	Default	Description
`lookahead_distance`	double	`5.0`	Maximum lookahead distance (m)
`min_lookahead_distance`	double	`2.0`	Minimum lookahead distance (m)
`lookahead_time`	double	`1.5`	Time-headway: `ld = lookahead_time · speed`, clamped to min/max (s)
`curvature_lookahead_gain`	double	`2.0`	Shrinks lookahead in curves: `ld_eff = ld / (1 + gain·\|κ\|)`
`speed_lookahead_distance`	double	`1.0`	Minimum distance ahead used to sample target speed (m)
`speed_lookahead_time`	double	`2.0`	Time-headway for the (decoupled, longer) speed sample horizon (s)

Steering & speed

Parameter	Type	Default	Description
`steering_angle_gain`	double	`1.0`	Gain on the pure-pursuit steering output
`max_steering_angle`	double	`0.5`	Maximum steering magnitude (rad)
`max_steering_rate`	double	`1.0`	Steering slew-rate limit (rad/s)
`max_speed` / `min_speed`	double	`5.0` / `0.0`	Commanded speed bounds while tracking (m/s)
`max_lateral_accel`	double	`2.5`	Cornering-speed budget: `v ≤ sqrt(a_lat/\|κ\|)` (m/s²)
`max_accel` / `max_decel`	double	`1.5` / `3.0`	Command accel/decel slew limits (m/s²)

Low-speed cross-track blend (Stanley)

Parameter	Type	Default	Description
`enable_stanley_blend`	bool	`false`	Blend a cross-track feedback term into steering at low speed
`stanley_gain`	double	`0.5`	Cross-track feedback gain `k_e`
`stanley_softening`	double	`1.0`	Softening constant `k_soft` (avoids blow-up near zero speed)
`stanley_speed_threshold`	double	`2.0`	Blend weight ramps from 1 (at 0) to 0 at this speed (m/s)

Disengage monitor

Parameter	Type	Default	Description
`enable_disengage`	bool	`true`	Enable the tracking-threshold disengage monitor
`max_cross_track_error`	double	`1.5`	Cross-track error that (sustained) trips a disengage (m)
`max_heading_error`	double	`0.6`	Heading error that (sustained) trips a disengage (rad)
`disengage_debounce_sec`	double	`0.5`	How long the error must be exceeded before tripping (s)
`disengage_latch`	bool	`false`	`true` = stay disengaged until reconfigured; `false` = auto-recover
`disengage_speed`	double	`0.0`	Safe speed commanded when no valid lookahead point exists (m/s)

Standby / misc

Parameter	Type	Default	Description
`standby_speed`	double	`-0.5`	Speed commanded during standby (m/s)
`standby_steering`	double	`0.0`	Steering commanded during standby (rad)
`control_rate_hz`	double	`20.0`	Control publish rate (Hz)
`wheelbase_fallback`	double	`2.5667`	Fallback wheelbase if the TF lookup fails (m)
`idle_timeout_sec`	double	`2.0`	Time since last trajectory before declaring idle (s)
`invert_steering`	bool	`true`	Invert steering sign — `true` means positive angle = clockwise
`disable_standby`	bool	`false`	Bypass standby and track even when `standby_msg` is received

Algorithm Details

File truncated at 100 lines see the full file

CHANGELOG

No CHANGELOG found.

Package Dependencies

Deps	Name
	ament_cmake
	wato_test
	rclcpp
	rclcpp_lifecycle
	behaviour_msgs
	geometry_msgs
	nav_msgs
	std_msgs
	ackermann_msgs
	tf2
	tf2_ros
	tf2_geometry_msgs
	wato_trajectory_msgs

System Dependencies

No direct system dependencies.

Dependant Packages

Name	Deps
action_bringup

Launch files

No launch files found

Messages

No message files found.

Services

No service files found

Plugins

No plugins found.

Recent questions tagged `ackermann_pure_pursuit` at Robotics Stack Exchange

No version for distro kilted showing jazzy. Known supported distros are highlighted in the buttons above.

ackermann_pure_pursuit package from wato_monorepo repo

ackermann_pure_pursuit action_bringup freeroam_planner global_planning lattice_planning lattice_planning_markers lattice_planning_msgs model_predictive_control mpc_controller osqp_eigen_vendor trajectory_planner wato_trajectory_msgs infrastructure_bringup tf_static_relay vision_msgs_markers wato_lifecycle_manager ackermann_mux camera_calib lidar_imu_calib lidar_lidar_calib can_state_estimator dummy_ackermann eve_description interfacing_bringup joystick_interfacing lidar_aggregator oscc_interfacing oscc_mux pid_control pid_msgs roscco_msg sensor_interfacing topic_healthchecker attribute_assigner bevfusion cuda_bevfusion_vendor depth_estimation feature_extraction patchworkpp patchworkpp_vendor perception_bringup perception_utils spatial_association bytetrack_cpp_vendor track_viz_2d tracking traffic_light_detection carla_bringup carla_common carla_control carla_lifecycle carla_localization carla_msgs carla_perception carla_pygame carla_ros_bridge carla_sample_description carla_scenarios carla_teleop simulation_bringup wato_test behaviortree_ros2_vendor behaviour behaviour_markers behaviour_msgs costmap costmap_markers costmap_msgs eidos eidos_msgs eidos_tools eidos_transform lanelet_markers lanelet_msgs lidar_localization prediction world_model world_model_markers world_model_msgs world_modeling_bringup

ROS Distro
jazzy

Package Summary

Version	0.1.0
License	Apache 2.0
Build type	AMENT_CMAKE
Use	RECOMMENDED

Repository Summary

Description
Checkout URI	https://github.com/WATonomous/wato_monorepo.git
VCS Type	git
VCS Version	main
Last Updated	2026-10-15
Dev Status	DEVELOPED
Released	UNRELEASED
Contributing	Help Wanted (-) Good First Issues (-) Pull Requests to Review (-)

Package Description

Pure pursuit controller for ackermann vehicles

Maintainers

WATonomous

Authors

No additional authors.

Ackermann Pure Pursuit

ROS2 lifecycle node that tracks a trajectory using the pure pursuit algorithm, publishing Ackermann drive commands for vehicle steering and speed control.

Overview

The pure pursuit node receives a planned trajectory, transforms each waypoint into the vehicle’s rear-axle reference frame (once per cycle), selects a lookahead point, and computes the steering angle and speed via the pure pursuit geometric algorithm. The lookahead distance is adapted to speed and path curvature, speed is limited by a lateral-acceleration budget, and the steering/speed commands are rate-limited for smoothness. Each cycle it measures cross-track and heading error and, if either exceeds a tunable threshold for a sustained window, raises a disengage recommendation in its ControllerStatus telemetry. This is advisory only: the controller keeps tracking normally and does not alter its command, yield the mux, or talk to the OSCC layer — acting on the recommendation is left to a higher-level supervisor. It publishes an idle signal and standby Ackermann commands when no valid trajectory is available, the trajectory has gone stale, or the behaviour tree requests standby.

Current Status: Adaptive pure pursuit controller with rear-axle geometry, TF-based wheelbase measurement, model-aware variable lookahead, curvature/accel-limited speed control, command-rate limiting, an optional low-speed Stanley cross-track blend, a debounced disengage monitor, and live-reconfigurable parameters.

ROS Interface

Subscribed Topics

Topic	Type	Description
`trajectory`	`wato_trajectory_msgs/Trajectory`	Planned trajectory from the freeroam planner
`execute_behaviour`	`behaviour_msgs/ExecuteBehaviour`	Requested behaviour from the behaviour tree

Published Topics

Topic	Type	Description
`/action/ackermann`	`ackermann_msgs/AckermannDriveStamped`	Steering angle and speed command
`/action/is_idle`	`std_msgs/Bool`	`true` when idle or in standby (the disengage monitor does not raise this)
`controller_status`	`wato_trajectory_msgs/ControllerStatus`	Per-cycle tracking error, effective lookahead, path curvature, commands, and disengage state/reason

Also subscribes to odom (nav_msgs/Odometry) for the current longitudinal speed used by the adaptive lookahead and speed scheduling.

Configuration

Parameters are loaded from config/params.yaml under the namespace action/pure_pursuit_node/ros__parameters.

Parameters are read once in on_configure. To change them at runtime, transition the lifecycle node back through cleanup → configure (which reloads config/params.yaml), as with the other action nodes.

Topics / frames

Parameter	Type	Default	Description
`controller_status_topic`	string	`"controller_status"`	Topic for the `ControllerStatus` telemetry
`base_frame`	string	`"base_footprint"`	Frame stamped on published Ackermann commands
`rear_axle_frame`	string	`"rear_axle"`	Frame the pure-pursuit geometry and tracking error are computed in; also one end of the TF wheelbase measurement
`front_axle_frame`	string	`"front_axle"`	Other end of the TF wheelbase measurement
`standby_msg`	string	`"standby"`	Behaviour string that triggers standby output

Adaptive lookahead

Parameter	Type	Default	Description
`lookahead_distance`	double	`5.0`	Maximum lookahead distance (m)
`min_lookahead_distance`	double	`2.0`	Minimum lookahead distance (m)
`lookahead_time`	double	`1.5`	Time-headway: `ld = lookahead_time · speed`, clamped to min/max (s)
`curvature_lookahead_gain`	double	`2.0`	Shrinks lookahead in curves: `ld_eff = ld / (1 + gain·\|κ\|)`
`speed_lookahead_distance`	double	`1.0`	Minimum distance ahead used to sample target speed (m)
`speed_lookahead_time`	double	`2.0`	Time-headway for the (decoupled, longer) speed sample horizon (s)

Steering & speed

Parameter	Type	Default	Description
`steering_angle_gain`	double	`1.0`	Gain on the pure-pursuit steering output
`max_steering_angle`	double	`0.5`	Maximum steering magnitude (rad)
`max_steering_rate`	double	`1.0`	Steering slew-rate limit (rad/s)
`max_speed` / `min_speed`	double	`5.0` / `0.0`	Commanded speed bounds while tracking (m/s)
`max_lateral_accel`	double	`2.5`	Cornering-speed budget: `v ≤ sqrt(a_lat/\|κ\|)` (m/s²)
`max_accel` / `max_decel`	double	`1.5` / `3.0`	Command accel/decel slew limits (m/s²)

Low-speed cross-track blend (Stanley)

Parameter	Type	Default	Description
`enable_stanley_blend`	bool	`false`	Blend a cross-track feedback term into steering at low speed
`stanley_gain`	double	`0.5`	Cross-track feedback gain `k_e`
`stanley_softening`	double	`1.0`	Softening constant `k_soft` (avoids blow-up near zero speed)
`stanley_speed_threshold`	double	`2.0`	Blend weight ramps from 1 (at 0) to 0 at this speed (m/s)

Disengage monitor

Parameter	Type	Default	Description
`enable_disengage`	bool	`true`	Enable the tracking-threshold disengage monitor
`max_cross_track_error`	double	`1.5`	Cross-track error that (sustained) trips a disengage (m)
`max_heading_error`	double	`0.6`	Heading error that (sustained) trips a disengage (rad)
`disengage_debounce_sec`	double	`0.5`	How long the error must be exceeded before tripping (s)
`disengage_latch`	bool	`false`	`true` = stay disengaged until reconfigured; `false` = auto-recover
`disengage_speed`	double	`0.0`	Safe speed commanded when no valid lookahead point exists (m/s)

Standby / misc

Parameter	Type	Default	Description
`standby_speed`	double	`-0.5`	Speed commanded during standby (m/s)
`standby_steering`	double	`0.0`	Steering commanded during standby (rad)
`control_rate_hz`	double	`20.0`	Control publish rate (Hz)
`wheelbase_fallback`	double	`2.5667`	Fallback wheelbase if the TF lookup fails (m)
`idle_timeout_sec`	double	`2.0`	Time since last trajectory before declaring idle (s)
`invert_steering`	bool	`true`	Invert steering sign — `true` means positive angle = clockwise
`disable_standby`	bool	`false`	Bypass standby and track even when `standby_msg` is received

Algorithm Details

File truncated at 100 lines see the full file

CHANGELOG

No CHANGELOG found.

Package Dependencies

Deps	Name
	ament_cmake
	wato_test
	rclcpp
	rclcpp_lifecycle
	behaviour_msgs
	geometry_msgs
	nav_msgs
	std_msgs
	ackermann_msgs
	tf2
	tf2_ros
	tf2_geometry_msgs
	wato_trajectory_msgs

System Dependencies

No direct system dependencies.

Dependant Packages

Name	Deps
action_bringup

Launch files

No launch files found

Messages

No message files found.

Services

No service files found

Plugins

No plugins found.

Recent questions tagged `ackermann_pure_pursuit` at Robotics Stack Exchange

No version for distro lyrical showing jazzy. Known supported distros are highlighted in the buttons above.

ackermann_pure_pursuit package from wato_monorepo repo

ackermann_pure_pursuit action_bringup freeroam_planner global_planning lattice_planning lattice_planning_markers lattice_planning_msgs model_predictive_control mpc_controller osqp_eigen_vendor trajectory_planner wato_trajectory_msgs infrastructure_bringup tf_static_relay vision_msgs_markers wato_lifecycle_manager ackermann_mux camera_calib lidar_imu_calib lidar_lidar_calib can_state_estimator dummy_ackermann eve_description interfacing_bringup joystick_interfacing lidar_aggregator oscc_interfacing oscc_mux pid_control pid_msgs roscco_msg sensor_interfacing topic_healthchecker attribute_assigner bevfusion cuda_bevfusion_vendor depth_estimation feature_extraction patchworkpp patchworkpp_vendor perception_bringup perception_utils spatial_association bytetrack_cpp_vendor track_viz_2d tracking traffic_light_detection carla_bringup carla_common carla_control carla_lifecycle carla_localization carla_msgs carla_perception carla_pygame carla_ros_bridge carla_sample_description carla_scenarios carla_teleop simulation_bringup wato_test behaviortree_ros2_vendor behaviour behaviour_markers behaviour_msgs costmap costmap_markers costmap_msgs eidos eidos_msgs eidos_tools eidos_transform lanelet_markers lanelet_msgs lidar_localization prediction world_model world_model_markers world_model_msgs world_modeling_bringup

ROS Distro
jazzy

Package Summary

Version	0.1.0
License	Apache 2.0
Build type	AMENT_CMAKE
Use	RECOMMENDED

Repository Summary

Description
Checkout URI	https://github.com/WATonomous/wato_monorepo.git
VCS Type	git
VCS Version	main
Last Updated	2026-10-15
Dev Status	DEVELOPED
Released	UNRELEASED
Contributing	Help Wanted (-) Good First Issues (-) Pull Requests to Review (-)

Package Description

Pure pursuit controller for ackermann vehicles

Maintainers

WATonomous

Authors

No additional authors.

Ackermann Pure Pursuit

ROS2 lifecycle node that tracks a trajectory using the pure pursuit algorithm, publishing Ackermann drive commands for vehicle steering and speed control.

Overview

The pure pursuit node receives a planned trajectory, transforms each waypoint into the vehicle’s rear-axle reference frame (once per cycle), selects a lookahead point, and computes the steering angle and speed via the pure pursuit geometric algorithm. The lookahead distance is adapted to speed and path curvature, speed is limited by a lateral-acceleration budget, and the steering/speed commands are rate-limited for smoothness. Each cycle it measures cross-track and heading error and, if either exceeds a tunable threshold for a sustained window, raises a disengage recommendation in its ControllerStatus telemetry. This is advisory only: the controller keeps tracking normally and does not alter its command, yield the mux, or talk to the OSCC layer — acting on the recommendation is left to a higher-level supervisor. It publishes an idle signal and standby Ackermann commands when no valid trajectory is available, the trajectory has gone stale, or the behaviour tree requests standby.

Current Status: Adaptive pure pursuit controller with rear-axle geometry, TF-based wheelbase measurement, model-aware variable lookahead, curvature/accel-limited speed control, command-rate limiting, an optional low-speed Stanley cross-track blend, a debounced disengage monitor, and live-reconfigurable parameters.

ROS Interface

Subscribed Topics

Topic	Type	Description
`trajectory`	`wato_trajectory_msgs/Trajectory`	Planned trajectory from the freeroam planner
`execute_behaviour`	`behaviour_msgs/ExecuteBehaviour`	Requested behaviour from the behaviour tree

Published Topics

Topic	Type	Description
`/action/ackermann`	`ackermann_msgs/AckermannDriveStamped`	Steering angle and speed command
`/action/is_idle`	`std_msgs/Bool`	`true` when idle or in standby (the disengage monitor does not raise this)
`controller_status`	`wato_trajectory_msgs/ControllerStatus`	Per-cycle tracking error, effective lookahead, path curvature, commands, and disengage state/reason

Also subscribes to odom (nav_msgs/Odometry) for the current longitudinal speed used by the adaptive lookahead and speed scheduling.

Configuration

Parameters are loaded from config/params.yaml under the namespace action/pure_pursuit_node/ros__parameters.

Parameters are read once in on_configure. To change them at runtime, transition the lifecycle node back through cleanup → configure (which reloads config/params.yaml), as with the other action nodes.

Topics / frames

Parameter	Type	Default	Description
`controller_status_topic`	string	`"controller_status"`	Topic for the `ControllerStatus` telemetry
`base_frame`	string	`"base_footprint"`	Frame stamped on published Ackermann commands
`rear_axle_frame`	string	`"rear_axle"`	Frame the pure-pursuit geometry and tracking error are computed in; also one end of the TF wheelbase measurement
`front_axle_frame`	string	`"front_axle"`	Other end of the TF wheelbase measurement
`standby_msg`	string	`"standby"`	Behaviour string that triggers standby output

Adaptive lookahead

Parameter	Type	Default	Description
`lookahead_distance`	double	`5.0`	Maximum lookahead distance (m)
`min_lookahead_distance`	double	`2.0`	Minimum lookahead distance (m)
`lookahead_time`	double	`1.5`	Time-headway: `ld = lookahead_time · speed`, clamped to min/max (s)
`curvature_lookahead_gain`	double	`2.0`	Shrinks lookahead in curves: `ld_eff = ld / (1 + gain·\|κ\|)`
`speed_lookahead_distance`	double	`1.0`	Minimum distance ahead used to sample target speed (m)
`speed_lookahead_time`	double	`2.0`	Time-headway for the (decoupled, longer) speed sample horizon (s)

Steering & speed

Parameter	Type	Default	Description
`steering_angle_gain`	double	`1.0`	Gain on the pure-pursuit steering output
`max_steering_angle`	double	`0.5`	Maximum steering magnitude (rad)
`max_steering_rate`	double	`1.0`	Steering slew-rate limit (rad/s)
`max_speed` / `min_speed`	double	`5.0` / `0.0`	Commanded speed bounds while tracking (m/s)
`max_lateral_accel`	double	`2.5`	Cornering-speed budget: `v ≤ sqrt(a_lat/\|κ\|)` (m/s²)
`max_accel` / `max_decel`	double	`1.5` / `3.0`	Command accel/decel slew limits (m/s²)

Low-speed cross-track blend (Stanley)

Parameter	Type	Default	Description
`enable_stanley_blend`	bool	`false`	Blend a cross-track feedback term into steering at low speed
`stanley_gain`	double	`0.5`	Cross-track feedback gain `k_e`
`stanley_softening`	double	`1.0`	Softening constant `k_soft` (avoids blow-up near zero speed)
`stanley_speed_threshold`	double	`2.0`	Blend weight ramps from 1 (at 0) to 0 at this speed (m/s)

Disengage monitor

Parameter	Type	Default	Description
`enable_disengage`	bool	`true`	Enable the tracking-threshold disengage monitor
`max_cross_track_error`	double	`1.5`	Cross-track error that (sustained) trips a disengage (m)
`max_heading_error`	double	`0.6`	Heading error that (sustained) trips a disengage (rad)
`disengage_debounce_sec`	double	`0.5`	How long the error must be exceeded before tripping (s)
`disengage_latch`	bool	`false`	`true` = stay disengaged until reconfigured; `false` = auto-recover
`disengage_speed`	double	`0.0`	Safe speed commanded when no valid lookahead point exists (m/s)

Standby / misc

Parameter	Type	Default	Description
`standby_speed`	double	`-0.5`	Speed commanded during standby (m/s)
`standby_steering`	double	`0.0`	Steering commanded during standby (rad)
`control_rate_hz`	double	`20.0`	Control publish rate (Hz)
`wheelbase_fallback`	double	`2.5667`	Fallback wheelbase if the TF lookup fails (m)
`idle_timeout_sec`	double	`2.0`	Time since last trajectory before declaring idle (s)
`invert_steering`	bool	`true`	Invert steering sign — `true` means positive angle = clockwise
`disable_standby`	bool	`false`	Bypass standby and track even when `standby_msg` is received

Algorithm Details

File truncated at 100 lines see the full file

CHANGELOG

No CHANGELOG found.

Package Dependencies

Deps	Name
	ament_cmake
	wato_test
	rclcpp
	rclcpp_lifecycle
	behaviour_msgs
	geometry_msgs
	nav_msgs
	std_msgs
	ackermann_msgs
	tf2
	tf2_ros
	tf2_geometry_msgs
	wato_trajectory_msgs

System Dependencies

No direct system dependencies.

Dependant Packages

Name	Deps
action_bringup

Launch files

No launch files found

Messages

No message files found.

Services

No service files found

Plugins

No plugins found.

Recent questions tagged `ackermann_pure_pursuit` at Robotics Stack Exchange

No version for distro rolling showing jazzy. Known supported distros are highlighted in the buttons above.

ackermann_pure_pursuit package from wato_monorepo repo

ackermann_pure_pursuit action_bringup freeroam_planner global_planning lattice_planning lattice_planning_markers lattice_planning_msgs model_predictive_control mpc_controller osqp_eigen_vendor trajectory_planner wato_trajectory_msgs infrastructure_bringup tf_static_relay vision_msgs_markers wato_lifecycle_manager ackermann_mux camera_calib lidar_imu_calib lidar_lidar_calib can_state_estimator dummy_ackermann eve_description interfacing_bringup joystick_interfacing lidar_aggregator oscc_interfacing oscc_mux pid_control pid_msgs roscco_msg sensor_interfacing topic_healthchecker attribute_assigner bevfusion cuda_bevfusion_vendor depth_estimation feature_extraction patchworkpp patchworkpp_vendor perception_bringup perception_utils spatial_association bytetrack_cpp_vendor track_viz_2d tracking traffic_light_detection carla_bringup carla_common carla_control carla_lifecycle carla_localization carla_msgs carla_perception carla_pygame carla_ros_bridge carla_sample_description carla_scenarios carla_teleop simulation_bringup wato_test behaviortree_ros2_vendor behaviour behaviour_markers behaviour_msgs costmap costmap_markers costmap_msgs eidos eidos_msgs eidos_tools eidos_transform lanelet_markers lanelet_msgs lidar_localization prediction world_model world_model_markers world_model_msgs world_modeling_bringup

ROS Distro
jazzy

Package Summary

Version	0.1.0
License	Apache 2.0
Build type	AMENT_CMAKE
Use	RECOMMENDED

Repository Summary

Description
Checkout URI	https://github.com/WATonomous/wato_monorepo.git
VCS Type	git
VCS Version	main
Last Updated	2026-10-15
Dev Status	DEVELOPED
Released	UNRELEASED
Contributing	Help Wanted (-) Good First Issues (-) Pull Requests to Review (-)

Package Description

Pure pursuit controller for ackermann vehicles

Maintainers

WATonomous

Authors

No additional authors.

Ackermann Pure Pursuit

ROS2 lifecycle node that tracks a trajectory using the pure pursuit algorithm, publishing Ackermann drive commands for vehicle steering and speed control.

Overview

The pure pursuit node receives a planned trajectory, transforms each waypoint into the vehicle’s rear-axle reference frame (once per cycle), selects a lookahead point, and computes the steering angle and speed via the pure pursuit geometric algorithm. The lookahead distance is adapted to speed and path curvature, speed is limited by a lateral-acceleration budget, and the steering/speed commands are rate-limited for smoothness. Each cycle it measures cross-track and heading error and, if either exceeds a tunable threshold for a sustained window, raises a disengage recommendation in its ControllerStatus telemetry. This is advisory only: the controller keeps tracking normally and does not alter its command, yield the mux, or talk to the OSCC layer — acting on the recommendation is left to a higher-level supervisor. It publishes an idle signal and standby Ackermann commands when no valid trajectory is available, the trajectory has gone stale, or the behaviour tree requests standby.

Current Status: Adaptive pure pursuit controller with rear-axle geometry, TF-based wheelbase measurement, model-aware variable lookahead, curvature/accel-limited speed control, command-rate limiting, an optional low-speed Stanley cross-track blend, a debounced disengage monitor, and live-reconfigurable parameters.

ROS Interface

Subscribed Topics

Topic	Type	Description
`trajectory`	`wato_trajectory_msgs/Trajectory`	Planned trajectory from the freeroam planner
`execute_behaviour`	`behaviour_msgs/ExecuteBehaviour`	Requested behaviour from the behaviour tree

Published Topics

Topic	Type	Description
`/action/ackermann`	`ackermann_msgs/AckermannDriveStamped`	Steering angle and speed command
`/action/is_idle`	`std_msgs/Bool`	`true` when idle or in standby (the disengage monitor does not raise this)
`controller_status`	`wato_trajectory_msgs/ControllerStatus`	Per-cycle tracking error, effective lookahead, path curvature, commands, and disengage state/reason

Also subscribes to odom (nav_msgs/Odometry) for the current longitudinal speed used by the adaptive lookahead and speed scheduling.

Configuration

Parameters are loaded from config/params.yaml under the namespace action/pure_pursuit_node/ros__parameters.

Parameters are read once in on_configure. To change them at runtime, transition the lifecycle node back through cleanup → configure (which reloads config/params.yaml), as with the other action nodes.

Topics / frames

Parameter	Type	Default	Description
`controller_status_topic`	string	`"controller_status"`	Topic for the `ControllerStatus` telemetry
`base_frame`	string	`"base_footprint"`	Frame stamped on published Ackermann commands
`rear_axle_frame`	string	`"rear_axle"`	Frame the pure-pursuit geometry and tracking error are computed in; also one end of the TF wheelbase measurement
`front_axle_frame`	string	`"front_axle"`	Other end of the TF wheelbase measurement
`standby_msg`	string	`"standby"`	Behaviour string that triggers standby output

Adaptive lookahead

Parameter	Type	Default	Description
`lookahead_distance`	double	`5.0`	Maximum lookahead distance (m)
`min_lookahead_distance`	double	`2.0`	Minimum lookahead distance (m)
`lookahead_time`	double	`1.5`	Time-headway: `ld = lookahead_time · speed`, clamped to min/max (s)
`curvature_lookahead_gain`	double	`2.0`	Shrinks lookahead in curves: `ld_eff = ld / (1 + gain·\|κ\|)`
`speed_lookahead_distance`	double	`1.0`	Minimum distance ahead used to sample target speed (m)
`speed_lookahead_time`	double	`2.0`	Time-headway for the (decoupled, longer) speed sample horizon (s)

Steering & speed

Parameter	Type	Default	Description
`steering_angle_gain`	double	`1.0`	Gain on the pure-pursuit steering output
`max_steering_angle`	double	`0.5`	Maximum steering magnitude (rad)
`max_steering_rate`	double	`1.0`	Steering slew-rate limit (rad/s)
`max_speed` / `min_speed`	double	`5.0` / `0.0`	Commanded speed bounds while tracking (m/s)
`max_lateral_accel`	double	`2.5`	Cornering-speed budget: `v ≤ sqrt(a_lat/\|κ\|)` (m/s²)
`max_accel` / `max_decel`	double	`1.5` / `3.0`	Command accel/decel slew limits (m/s²)

Low-speed cross-track blend (Stanley)

Parameter	Type	Default	Description
`enable_stanley_blend`	bool	`false`	Blend a cross-track feedback term into steering at low speed
`stanley_gain`	double	`0.5`	Cross-track feedback gain `k_e`
`stanley_softening`	double	`1.0`	Softening constant `k_soft` (avoids blow-up near zero speed)
`stanley_speed_threshold`	double	`2.0`	Blend weight ramps from 1 (at 0) to 0 at this speed (m/s)

Disengage monitor

Parameter	Type	Default	Description
`enable_disengage`	bool	`true`	Enable the tracking-threshold disengage monitor
`max_cross_track_error`	double	`1.5`	Cross-track error that (sustained) trips a disengage (m)
`max_heading_error`	double	`0.6`	Heading error that (sustained) trips a disengage (rad)
`disengage_debounce_sec`	double	`0.5`	How long the error must be exceeded before tripping (s)
`disengage_latch`	bool	`false`	`true` = stay disengaged until reconfigured; `false` = auto-recover
`disengage_speed`	double	`0.0`	Safe speed commanded when no valid lookahead point exists (m/s)

Standby / misc

Parameter	Type	Default	Description
`standby_speed`	double	`-0.5`	Speed commanded during standby (m/s)
`standby_steering`	double	`0.0`	Steering commanded during standby (rad)
`control_rate_hz`	double	`20.0`	Control publish rate (Hz)
`wheelbase_fallback`	double	`2.5667`	Fallback wheelbase if the TF lookup fails (m)
`idle_timeout_sec`	double	`2.0`	Time since last trajectory before declaring idle (s)
`invert_steering`	bool	`true`	Invert steering sign — `true` means positive angle = clockwise
`disable_standby`	bool	`false`	Bypass standby and track even when `standby_msg` is received

Algorithm Details

File truncated at 100 lines see the full file

CHANGELOG

No CHANGELOG found.

Package Dependencies

Deps	Name
	ament_cmake
	wato_test
	rclcpp
	rclcpp_lifecycle
	behaviour_msgs
	geometry_msgs
	nav_msgs
	std_msgs
	ackermann_msgs
	tf2
	tf2_ros
	tf2_geometry_msgs
	wato_trajectory_msgs

System Dependencies

No direct system dependencies.

Dependant Packages

Name	Deps
action_bringup

Launch files

No launch files found

Messages

No message files found.

Services

No service files found

Plugins

No plugins found.

Recent questions tagged `ackermann_pure_pursuit` at Robotics Stack Exchange

ackermann_pure_pursuit package from wato_monorepo repo

ackermann_pure_pursuit action_bringup freeroam_planner global_planning lattice_planning lattice_planning_markers lattice_planning_msgs model_predictive_control mpc_controller osqp_eigen_vendor trajectory_planner wato_trajectory_msgs infrastructure_bringup tf_static_relay vision_msgs_markers wato_lifecycle_manager ackermann_mux camera_calib lidar_imu_calib lidar_lidar_calib can_state_estimator dummy_ackermann eve_description interfacing_bringup joystick_interfacing lidar_aggregator oscc_interfacing oscc_mux pid_control pid_msgs roscco_msg sensor_interfacing topic_healthchecker attribute_assigner bevfusion cuda_bevfusion_vendor depth_estimation feature_extraction patchworkpp patchworkpp_vendor perception_bringup perception_utils spatial_association bytetrack_cpp_vendor track_viz_2d tracking traffic_light_detection carla_bringup carla_common carla_control carla_lifecycle carla_localization carla_msgs carla_perception carla_pygame carla_ros_bridge carla_sample_description carla_scenarios carla_teleop simulation_bringup wato_test behaviortree_ros2_vendor behaviour behaviour_markers behaviour_msgs costmap costmap_markers costmap_msgs eidos eidos_msgs eidos_tools eidos_transform lanelet_markers lanelet_msgs lidar_localization prediction world_model world_model_markers world_model_msgs world_modeling_bringup

ROS Distro
github

Package Summary

Version	0.1.0
License	Apache 2.0
Build type	AMENT_CMAKE
Use	RECOMMENDED

Repository Summary

Description
Checkout URI	https://github.com/watonomous/wato_monorepo.git
VCS Type	git
VCS Version	main
Last Updated	2026-10-15
Dev Status	UNKNOWN
Released	UNRELEASED
Contributing	Help Wanted (-) Good First Issues (-) Pull Requests to Review (-)

Package Description

Pure pursuit controller for ackermann vehicles

Maintainers

WATonomous

Authors

No additional authors.

Ackermann Pure Pursuit

ROS2 lifecycle node that tracks a trajectory using the pure pursuit algorithm, publishing Ackermann drive commands for vehicle steering and speed control.

Overview

The pure pursuit node receives a planned trajectory, transforms each waypoint into the vehicle’s rear-axle reference frame (once per cycle), selects a lookahead point, and computes the steering angle and speed via the pure pursuit geometric algorithm. The lookahead distance is adapted to speed and path curvature, speed is limited by a lateral-acceleration budget, and the steering/speed commands are rate-limited for smoothness. Each cycle it measures cross-track and heading error and, if either exceeds a tunable threshold for a sustained window, raises a disengage recommendation in its ControllerStatus telemetry. This is advisory only: the controller keeps tracking normally and does not alter its command, yield the mux, or talk to the OSCC layer — acting on the recommendation is left to a higher-level supervisor. It publishes an idle signal and standby Ackermann commands when no valid trajectory is available, the trajectory has gone stale, or the behaviour tree requests standby.

Current Status: Adaptive pure pursuit controller with rear-axle geometry, TF-based wheelbase measurement, model-aware variable lookahead, curvature/accel-limited speed control, command-rate limiting, an optional low-speed Stanley cross-track blend, a debounced disengage monitor, and live-reconfigurable parameters.

ROS Interface

Subscribed Topics

Topic	Type	Description
`trajectory`	`wato_trajectory_msgs/Trajectory`	Planned trajectory from the freeroam planner
`execute_behaviour`	`behaviour_msgs/ExecuteBehaviour`	Requested behaviour from the behaviour tree

Published Topics

Topic	Type	Description
`/action/ackermann`	`ackermann_msgs/AckermannDriveStamped`	Steering angle and speed command
`/action/is_idle`	`std_msgs/Bool`	`true` when idle or in standby (the disengage monitor does not raise this)
`controller_status`	`wato_trajectory_msgs/ControllerStatus`	Per-cycle tracking error, effective lookahead, path curvature, commands, and disengage state/reason

Also subscribes to odom (nav_msgs/Odometry) for the current longitudinal speed used by the adaptive lookahead and speed scheduling.

Configuration

Parameters are loaded from config/params.yaml under the namespace action/pure_pursuit_node/ros__parameters.

Parameters are read once in on_configure. To change them at runtime, transition the lifecycle node back through cleanup → configure (which reloads config/params.yaml), as with the other action nodes.

Topics / frames

Parameter	Type	Default	Description
`controller_status_topic`	string	`"controller_status"`	Topic for the `ControllerStatus` telemetry
`base_frame`	string	`"base_footprint"`	Frame stamped on published Ackermann commands
`rear_axle_frame`	string	`"rear_axle"`	Frame the pure-pursuit geometry and tracking error are computed in; also one end of the TF wheelbase measurement
`front_axle_frame`	string	`"front_axle"`	Other end of the TF wheelbase measurement
`standby_msg`	string	`"standby"`	Behaviour string that triggers standby output

Adaptive lookahead

Parameter	Type	Default	Description
`lookahead_distance`	double	`5.0`	Maximum lookahead distance (m)
`min_lookahead_distance`	double	`2.0`	Minimum lookahead distance (m)
`lookahead_time`	double	`1.5`	Time-headway: `ld = lookahead_time · speed`, clamped to min/max (s)
`curvature_lookahead_gain`	double	`2.0`	Shrinks lookahead in curves: `ld_eff = ld / (1 + gain·\|κ\|)`
`speed_lookahead_distance`	double	`1.0`	Minimum distance ahead used to sample target speed (m)
`speed_lookahead_time`	double	`2.0`	Time-headway for the (decoupled, longer) speed sample horizon (s)

Steering & speed

Parameter	Type	Default	Description
`steering_angle_gain`	double	`1.0`	Gain on the pure-pursuit steering output
`max_steering_angle`	double	`0.5`	Maximum steering magnitude (rad)
`max_steering_rate`	double	`1.0`	Steering slew-rate limit (rad/s)
`max_speed` / `min_speed`	double	`5.0` / `0.0`	Commanded speed bounds while tracking (m/s)
`max_lateral_accel`	double	`2.5`	Cornering-speed budget: `v ≤ sqrt(a_lat/\|κ\|)` (m/s²)
`max_accel` / `max_decel`	double	`1.5` / `3.0`	Command accel/decel slew limits (m/s²)

Low-speed cross-track blend (Stanley)

Parameter	Type	Default	Description
`enable_stanley_blend`	bool	`false`	Blend a cross-track feedback term into steering at low speed
`stanley_gain`	double	`0.5`	Cross-track feedback gain `k_e`
`stanley_softening`	double	`1.0`	Softening constant `k_soft` (avoids blow-up near zero speed)
`stanley_speed_threshold`	double	`2.0`	Blend weight ramps from 1 (at 0) to 0 at this speed (m/s)

Disengage monitor

Parameter	Type	Default	Description
`enable_disengage`	bool	`true`	Enable the tracking-threshold disengage monitor
`max_cross_track_error`	double	`1.5`	Cross-track error that (sustained) trips a disengage (m)
`max_heading_error`	double	`0.6`	Heading error that (sustained) trips a disengage (rad)
`disengage_debounce_sec`	double	`0.5`	How long the error must be exceeded before tripping (s)
`disengage_latch`	bool	`false`	`true` = stay disengaged until reconfigured; `false` = auto-recover
`disengage_speed`	double	`0.0`	Safe speed commanded when no valid lookahead point exists (m/s)

Standby / misc

Parameter	Type	Default	Description
`standby_speed`	double	`-0.5`	Speed commanded during standby (m/s)
`standby_steering`	double	`0.0`	Steering commanded during standby (rad)
`control_rate_hz`	double	`20.0`	Control publish rate (Hz)
`wheelbase_fallback`	double	`2.5667`	Fallback wheelbase if the TF lookup fails (m)
`idle_timeout_sec`	double	`2.0`	Time since last trajectory before declaring idle (s)
`invert_steering`	bool	`true`	Invert steering sign — `true` means positive angle = clockwise
`disable_standby`	bool	`false`	Bypass standby and track even when `standby_msg` is received

Algorithm Details

File truncated at 100 lines see the full file

CHANGELOG

No CHANGELOG found.

Package Dependencies

Deps	Name
	ament_cmake
	wato_test
	rclcpp
	rclcpp_lifecycle
	behaviour_msgs
	geometry_msgs
	nav_msgs
	std_msgs
	ackermann_msgs
	tf2
	tf2_ros
	tf2_geometry_msgs
	wato_trajectory_msgs

System Dependencies

No direct system dependencies.

Dependant Packages

Name	Deps
action_bringup

Launch files

No launch files found

Messages

No message files found.

Services

No service files found

Plugins

No plugins found.

Recent questions tagged `ackermann_pure_pursuit` at Robotics Stack Exchange

No version for distro galactic showing jazzy. Known supported distros are highlighted in the buttons above.

ackermann_pure_pursuit package from wato_monorepo repo

ackermann_pure_pursuit action_bringup freeroam_planner global_planning lattice_planning lattice_planning_markers lattice_planning_msgs model_predictive_control mpc_controller osqp_eigen_vendor trajectory_planner wato_trajectory_msgs infrastructure_bringup tf_static_relay vision_msgs_markers wato_lifecycle_manager ackermann_mux camera_calib lidar_imu_calib lidar_lidar_calib can_state_estimator dummy_ackermann eve_description interfacing_bringup joystick_interfacing lidar_aggregator oscc_interfacing oscc_mux pid_control pid_msgs roscco_msg sensor_interfacing topic_healthchecker attribute_assigner bevfusion cuda_bevfusion_vendor depth_estimation feature_extraction patchworkpp patchworkpp_vendor perception_bringup perception_utils spatial_association bytetrack_cpp_vendor track_viz_2d tracking traffic_light_detection carla_bringup carla_common carla_control carla_lifecycle carla_localization carla_msgs carla_perception carla_pygame carla_ros_bridge carla_sample_description carla_scenarios carla_teleop simulation_bringup wato_test behaviortree_ros2_vendor behaviour behaviour_markers behaviour_msgs costmap costmap_markers costmap_msgs eidos eidos_msgs eidos_tools eidos_transform lanelet_markers lanelet_msgs lidar_localization prediction world_model world_model_markers world_model_msgs world_modeling_bringup

ROS Distro
jazzy

Package Summary

Version	0.1.0
License	Apache 2.0
Build type	AMENT_CMAKE
Use	RECOMMENDED

Repository Summary

Description
Checkout URI	https://github.com/WATonomous/wato_monorepo.git
VCS Type	git
VCS Version	main
Last Updated	2026-10-15
Dev Status	DEVELOPED
Released	UNRELEASED
Contributing	Help Wanted (-) Good First Issues (-) Pull Requests to Review (-)

Package Description

Pure pursuit controller for ackermann vehicles

Maintainers

WATonomous

Authors

No additional authors.

Ackermann Pure Pursuit

ROS2 lifecycle node that tracks a trajectory using the pure pursuit algorithm, publishing Ackermann drive commands for vehicle steering and speed control.

Overview

The pure pursuit node receives a planned trajectory, transforms each waypoint into the vehicle’s rear-axle reference frame (once per cycle), selects a lookahead point, and computes the steering angle and speed via the pure pursuit geometric algorithm. The lookahead distance is adapted to speed and path curvature, speed is limited by a lateral-acceleration budget, and the steering/speed commands are rate-limited for smoothness. Each cycle it measures cross-track and heading error and, if either exceeds a tunable threshold for a sustained window, raises a disengage recommendation in its ControllerStatus telemetry. This is advisory only: the controller keeps tracking normally and does not alter its command, yield the mux, or talk to the OSCC layer — acting on the recommendation is left to a higher-level supervisor. It publishes an idle signal and standby Ackermann commands when no valid trajectory is available, the trajectory has gone stale, or the behaviour tree requests standby.

Current Status: Adaptive pure pursuit controller with rear-axle geometry, TF-based wheelbase measurement, model-aware variable lookahead, curvature/accel-limited speed control, command-rate limiting, an optional low-speed Stanley cross-track blend, a debounced disengage monitor, and live-reconfigurable parameters.

ROS Interface

Subscribed Topics

Topic	Type	Description
`trajectory`	`wato_trajectory_msgs/Trajectory`	Planned trajectory from the freeroam planner
`execute_behaviour`	`behaviour_msgs/ExecuteBehaviour`	Requested behaviour from the behaviour tree

Published Topics

Topic	Type	Description
`/action/ackermann`	`ackermann_msgs/AckermannDriveStamped`	Steering angle and speed command
`/action/is_idle`	`std_msgs/Bool`	`true` when idle or in standby (the disengage monitor does not raise this)
`controller_status`	`wato_trajectory_msgs/ControllerStatus`	Per-cycle tracking error, effective lookahead, path curvature, commands, and disengage state/reason

Also subscribes to odom (nav_msgs/Odometry) for the current longitudinal speed used by the adaptive lookahead and speed scheduling.

Configuration

Parameters are loaded from config/params.yaml under the namespace action/pure_pursuit_node/ros__parameters.

Parameters are read once in on_configure. To change them at runtime, transition the lifecycle node back through cleanup → configure (which reloads config/params.yaml), as with the other action nodes.

Topics / frames

Parameter	Type	Default	Description
`controller_status_topic`	string	`"controller_status"`	Topic for the `ControllerStatus` telemetry
`base_frame`	string	`"base_footprint"`	Frame stamped on published Ackermann commands
`rear_axle_frame`	string	`"rear_axle"`	Frame the pure-pursuit geometry and tracking error are computed in; also one end of the TF wheelbase measurement
`front_axle_frame`	string	`"front_axle"`	Other end of the TF wheelbase measurement
`standby_msg`	string	`"standby"`	Behaviour string that triggers standby output

Adaptive lookahead

Parameter	Type	Default	Description
`lookahead_distance`	double	`5.0`	Maximum lookahead distance (m)
`min_lookahead_distance`	double	`2.0`	Minimum lookahead distance (m)
`lookahead_time`	double	`1.5`	Time-headway: `ld = lookahead_time · speed`, clamped to min/max (s)
`curvature_lookahead_gain`	double	`2.0`	Shrinks lookahead in curves: `ld_eff = ld / (1 + gain·\|κ\|)`
`speed_lookahead_distance`	double	`1.0`	Minimum distance ahead used to sample target speed (m)
`speed_lookahead_time`	double	`2.0`	Time-headway for the (decoupled, longer) speed sample horizon (s)

Steering & speed

Parameter	Type	Default	Description
`steering_angle_gain`	double	`1.0`	Gain on the pure-pursuit steering output
`max_steering_angle`	double	`0.5`	Maximum steering magnitude (rad)
`max_steering_rate`	double	`1.0`	Steering slew-rate limit (rad/s)
`max_speed` / `min_speed`	double	`5.0` / `0.0`	Commanded speed bounds while tracking (m/s)
`max_lateral_accel`	double	`2.5`	Cornering-speed budget: `v ≤ sqrt(a_lat/\|κ\|)` (m/s²)
`max_accel` / `max_decel`	double	`1.5` / `3.0`	Command accel/decel slew limits (m/s²)

Low-speed cross-track blend (Stanley)

Parameter	Type	Default	Description
`enable_stanley_blend`	bool	`false`	Blend a cross-track feedback term into steering at low speed
`stanley_gain`	double	`0.5`	Cross-track feedback gain `k_e`
`stanley_softening`	double	`1.0`	Softening constant `k_soft` (avoids blow-up near zero speed)
`stanley_speed_threshold`	double	`2.0`	Blend weight ramps from 1 (at 0) to 0 at this speed (m/s)

Disengage monitor

Parameter	Type	Default	Description
`enable_disengage`	bool	`true`	Enable the tracking-threshold disengage monitor
`max_cross_track_error`	double	`1.5`	Cross-track error that (sustained) trips a disengage (m)
`max_heading_error`	double	`0.6`	Heading error that (sustained) trips a disengage (rad)
`disengage_debounce_sec`	double	`0.5`	How long the error must be exceeded before tripping (s)
`disengage_latch`	bool	`false`	`true` = stay disengaged until reconfigured; `false` = auto-recover
`disengage_speed`	double	`0.0`	Safe speed commanded when no valid lookahead point exists (m/s)

Standby / misc

Parameter	Type	Default	Description
`standby_speed`	double	`-0.5`	Speed commanded during standby (m/s)
`standby_steering`	double	`0.0`	Steering commanded during standby (rad)
`control_rate_hz`	double	`20.0`	Control publish rate (Hz)
`wheelbase_fallback`	double	`2.5667`	Fallback wheelbase if the TF lookup fails (m)
`idle_timeout_sec`	double	`2.0`	Time since last trajectory before declaring idle (s)
`invert_steering`	bool	`true`	Invert steering sign — `true` means positive angle = clockwise
`disable_standby`	bool	`false`	Bypass standby and track even when `standby_msg` is received

Algorithm Details

File truncated at 100 lines see the full file

CHANGELOG

No CHANGELOG found.

Package Dependencies

Deps	Name
	ament_cmake
	wato_test
	rclcpp
	rclcpp_lifecycle
	behaviour_msgs
	geometry_msgs
	nav_msgs
	std_msgs
	ackermann_msgs
	tf2
	tf2_ros
	tf2_geometry_msgs
	wato_trajectory_msgs

System Dependencies

No direct system dependencies.

Dependant Packages

Name	Deps
action_bringup

Launch files

No launch files found

Messages

No message files found.

Services

No service files found

Plugins

No plugins found.

Recent questions tagged `ackermann_pure_pursuit` at Robotics Stack Exchange

No version for distro iron showing jazzy. Known supported distros are highlighted in the buttons above.

ackermann_pure_pursuit package from wato_monorepo repo

ackermann_pure_pursuit action_bringup freeroam_planner global_planning lattice_planning lattice_planning_markers lattice_planning_msgs model_predictive_control mpc_controller osqp_eigen_vendor trajectory_planner wato_trajectory_msgs infrastructure_bringup tf_static_relay vision_msgs_markers wato_lifecycle_manager ackermann_mux camera_calib lidar_imu_calib lidar_lidar_calib can_state_estimator dummy_ackermann eve_description interfacing_bringup joystick_interfacing lidar_aggregator oscc_interfacing oscc_mux pid_control pid_msgs roscco_msg sensor_interfacing topic_healthchecker attribute_assigner bevfusion cuda_bevfusion_vendor depth_estimation feature_extraction patchworkpp patchworkpp_vendor perception_bringup perception_utils spatial_association bytetrack_cpp_vendor track_viz_2d tracking traffic_light_detection carla_bringup carla_common carla_control carla_lifecycle carla_localization carla_msgs carla_perception carla_pygame carla_ros_bridge carla_sample_description carla_scenarios carla_teleop simulation_bringup wato_test behaviortree_ros2_vendor behaviour behaviour_markers behaviour_msgs costmap costmap_markers costmap_msgs eidos eidos_msgs eidos_tools eidos_transform lanelet_markers lanelet_msgs lidar_localization prediction world_model world_model_markers world_model_msgs world_modeling_bringup

ROS Distro
jazzy

Package Summary

Version	0.1.0
License	Apache 2.0
Build type	AMENT_CMAKE
Use	RECOMMENDED

Repository Summary

Description
Checkout URI	https://github.com/WATonomous/wato_monorepo.git
VCS Type	git
VCS Version	main
Last Updated	2026-10-15
Dev Status	DEVELOPED
Released	UNRELEASED
Contributing	Help Wanted (-) Good First Issues (-) Pull Requests to Review (-)

Package Description

Pure pursuit controller for ackermann vehicles

Maintainers

WATonomous

Authors

No additional authors.

Ackermann Pure Pursuit

ROS2 lifecycle node that tracks a trajectory using the pure pursuit algorithm, publishing Ackermann drive commands for vehicle steering and speed control.

Overview

The pure pursuit node receives a planned trajectory, transforms each waypoint into the vehicle’s rear-axle reference frame (once per cycle), selects a lookahead point, and computes the steering angle and speed via the pure pursuit geometric algorithm. The lookahead distance is adapted to speed and path curvature, speed is limited by a lateral-acceleration budget, and the steering/speed commands are rate-limited for smoothness. Each cycle it measures cross-track and heading error and, if either exceeds a tunable threshold for a sustained window, raises a disengage recommendation in its ControllerStatus telemetry. This is advisory only: the controller keeps tracking normally and does not alter its command, yield the mux, or talk to the OSCC layer — acting on the recommendation is left to a higher-level supervisor. It publishes an idle signal and standby Ackermann commands when no valid trajectory is available, the trajectory has gone stale, or the behaviour tree requests standby.

Current Status: Adaptive pure pursuit controller with rear-axle geometry, TF-based wheelbase measurement, model-aware variable lookahead, curvature/accel-limited speed control, command-rate limiting, an optional low-speed Stanley cross-track blend, a debounced disengage monitor, and live-reconfigurable parameters.

ROS Interface

Subscribed Topics

Topic	Type	Description
`trajectory`	`wato_trajectory_msgs/Trajectory`	Planned trajectory from the freeroam planner
`execute_behaviour`	`behaviour_msgs/ExecuteBehaviour`	Requested behaviour from the behaviour tree

Published Topics

Topic	Type	Description
`/action/ackermann`	`ackermann_msgs/AckermannDriveStamped`	Steering angle and speed command
`/action/is_idle`	`std_msgs/Bool`	`true` when idle or in standby (the disengage monitor does not raise this)
`controller_status`	`wato_trajectory_msgs/ControllerStatus`	Per-cycle tracking error, effective lookahead, path curvature, commands, and disengage state/reason

Also subscribes to odom (nav_msgs/Odometry) for the current longitudinal speed used by the adaptive lookahead and speed scheduling.

Configuration

Parameters are loaded from config/params.yaml under the namespace action/pure_pursuit_node/ros__parameters.

Parameters are read once in on_configure. To change them at runtime, transition the lifecycle node back through cleanup → configure (which reloads config/params.yaml), as with the other action nodes.

Topics / frames

Parameter	Type	Default	Description
`controller_status_topic`	string	`"controller_status"`	Topic for the `ControllerStatus` telemetry
`base_frame`	string	`"base_footprint"`	Frame stamped on published Ackermann commands
`rear_axle_frame`	string	`"rear_axle"`	Frame the pure-pursuit geometry and tracking error are computed in; also one end of the TF wheelbase measurement
`front_axle_frame`	string	`"front_axle"`	Other end of the TF wheelbase measurement
`standby_msg`	string	`"standby"`	Behaviour string that triggers standby output

Adaptive lookahead

Parameter	Type	Default	Description
`lookahead_distance`	double	`5.0`	Maximum lookahead distance (m)
`min_lookahead_distance`	double	`2.0`	Minimum lookahead distance (m)
`lookahead_time`	double	`1.5`	Time-headway: `ld = lookahead_time · speed`, clamped to min/max (s)
`curvature_lookahead_gain`	double	`2.0`	Shrinks lookahead in curves: `ld_eff = ld / (1 + gain·\|κ\|)`
`speed_lookahead_distance`	double	`1.0`	Minimum distance ahead used to sample target speed (m)
`speed_lookahead_time`	double	`2.0`	Time-headway for the (decoupled, longer) speed sample horizon (s)

Steering & speed

Parameter	Type	Default	Description
`steering_angle_gain`	double	`1.0`	Gain on the pure-pursuit steering output
`max_steering_angle`	double	`0.5`	Maximum steering magnitude (rad)
`max_steering_rate`	double	`1.0`	Steering slew-rate limit (rad/s)
`max_speed` / `min_speed`	double	`5.0` / `0.0`	Commanded speed bounds while tracking (m/s)
`max_lateral_accel`	double	`2.5`	Cornering-speed budget: `v ≤ sqrt(a_lat/\|κ\|)` (m/s²)
`max_accel` / `max_decel`	double	`1.5` / `3.0`	Command accel/decel slew limits (m/s²)

Low-speed cross-track blend (Stanley)

Parameter	Type	Default	Description
`enable_stanley_blend`	bool	`false`	Blend a cross-track feedback term into steering at low speed
`stanley_gain`	double	`0.5`	Cross-track feedback gain `k_e`
`stanley_softening`	double	`1.0`	Softening constant `k_soft` (avoids blow-up near zero speed)
`stanley_speed_threshold`	double	`2.0`	Blend weight ramps from 1 (at 0) to 0 at this speed (m/s)

Disengage monitor

Parameter	Type	Default	Description
`enable_disengage`	bool	`true`	Enable the tracking-threshold disengage monitor
`max_cross_track_error`	double	`1.5`	Cross-track error that (sustained) trips a disengage (m)
`max_heading_error`	double	`0.6`	Heading error that (sustained) trips a disengage (rad)
`disengage_debounce_sec`	double	`0.5`	How long the error must be exceeded before tripping (s)
`disengage_latch`	bool	`false`	`true` = stay disengaged until reconfigured; `false` = auto-recover
`disengage_speed`	double	`0.0`	Safe speed commanded when no valid lookahead point exists (m/s)

Standby / misc

Parameter	Type	Default	Description
`standby_speed`	double	`-0.5`	Speed commanded during standby (m/s)
`standby_steering`	double	`0.0`	Steering commanded during standby (rad)
`control_rate_hz`	double	`20.0`	Control publish rate (Hz)
`wheelbase_fallback`	double	`2.5667`	Fallback wheelbase if the TF lookup fails (m)
`idle_timeout_sec`	double	`2.0`	Time since last trajectory before declaring idle (s)
`invert_steering`	bool	`true`	Invert steering sign — `true` means positive angle = clockwise
`disable_standby`	bool	`false`	Bypass standby and track even when `standby_msg` is received

Algorithm Details

File truncated at 100 lines see the full file

CHANGELOG

No CHANGELOG found.

Package Dependencies

Deps	Name
	ament_cmake
	wato_test
	rclcpp
	rclcpp_lifecycle
	behaviour_msgs
	geometry_msgs
	nav_msgs
	std_msgs
	ackermann_msgs
	tf2
	tf2_ros
	tf2_geometry_msgs
	wato_trajectory_msgs

System Dependencies

No direct system dependencies.

Dependant Packages

Name	Deps
action_bringup

Launch files

No launch files found

Messages

No message files found.

Services

No service files found

Plugins

No plugins found.

Recent questions tagged `ackermann_pure_pursuit` at Robotics Stack Exchange

No version for distro melodic showing jazzy. Known supported distros are highlighted in the buttons above.

ackermann_pure_pursuit package from wato_monorepo repo

ackermann_pure_pursuit action_bringup freeroam_planner global_planning lattice_planning lattice_planning_markers lattice_planning_msgs model_predictive_control mpc_controller osqp_eigen_vendor trajectory_planner wato_trajectory_msgs infrastructure_bringup tf_static_relay vision_msgs_markers wato_lifecycle_manager ackermann_mux camera_calib lidar_imu_calib lidar_lidar_calib can_state_estimator dummy_ackermann eve_description interfacing_bringup joystick_interfacing lidar_aggregator oscc_interfacing oscc_mux pid_control pid_msgs roscco_msg sensor_interfacing topic_healthchecker attribute_assigner bevfusion cuda_bevfusion_vendor depth_estimation feature_extraction patchworkpp patchworkpp_vendor perception_bringup perception_utils spatial_association bytetrack_cpp_vendor track_viz_2d tracking traffic_light_detection carla_bringup carla_common carla_control carla_lifecycle carla_localization carla_msgs carla_perception carla_pygame carla_ros_bridge carla_sample_description carla_scenarios carla_teleop simulation_bringup wato_test behaviortree_ros2_vendor behaviour behaviour_markers behaviour_msgs costmap costmap_markers costmap_msgs eidos eidos_msgs eidos_tools eidos_transform lanelet_markers lanelet_msgs lidar_localization prediction world_model world_model_markers world_model_msgs world_modeling_bringup

ROS Distro
jazzy

API Docs
Browse Code
Wiki

Package Summary

Version	0.1.0
License	Apache 2.0
Build type	AMENT_CMAKE
Use	RECOMMENDED

Repository Summary

Description
Checkout URI	https://github.com/WATonomous/wato_monorepo.git
VCS Type	git
VCS Version	main
Last Updated	2026-10-15
Dev Status	DEVELOPED
Released	UNRELEASED
Contributing	Help Wanted (-) Good First Issues (-) Pull Requests to Review (-)

Package Description

Pure pursuit controller for ackermann vehicles

Maintainers

WATonomous

Authors

No additional authors.

Ackermann Pure Pursuit

ROS2 lifecycle node that tracks a trajectory using the pure pursuit algorithm, publishing Ackermann drive commands for vehicle steering and speed control.

Overview

The pure pursuit node receives a planned trajectory, transforms each waypoint into the vehicle’s rear-axle reference frame (once per cycle), selects a lookahead point, and computes the steering angle and speed via the pure pursuit geometric algorithm. The lookahead distance is adapted to speed and path curvature, speed is limited by a lateral-acceleration budget, and the steering/speed commands are rate-limited for smoothness. Each cycle it measures cross-track and heading error and, if either exceeds a tunable threshold for a sustained window, raises a disengage recommendation in its ControllerStatus telemetry. This is advisory only: the controller keeps tracking normally and does not alter its command, yield the mux, or talk to the OSCC layer — acting on the recommendation is left to a higher-level supervisor. It publishes an idle signal and standby Ackermann commands when no valid trajectory is available, the trajectory has gone stale, or the behaviour tree requests standby.

Current Status: Adaptive pure pursuit controller with rear-axle geometry, TF-based wheelbase measurement, model-aware variable lookahead, curvature/accel-limited speed control, command-rate limiting, an optional low-speed Stanley cross-track blend, a debounced disengage monitor, and live-reconfigurable parameters.

ROS Interface

Subscribed Topics

Topic	Type	Description
`trajectory`	`wato_trajectory_msgs/Trajectory`	Planned trajectory from the freeroam planner
`execute_behaviour`	`behaviour_msgs/ExecuteBehaviour`	Requested behaviour from the behaviour tree

Published Topics

Topic	Type	Description
`/action/ackermann`	`ackermann_msgs/AckermannDriveStamped`	Steering angle and speed command
`/action/is_idle`	`std_msgs/Bool`	`true` when idle or in standby (the disengage monitor does not raise this)
`controller_status`	`wato_trajectory_msgs/ControllerStatus`	Per-cycle tracking error, effective lookahead, path curvature, commands, and disengage state/reason

Also subscribes to odom (nav_msgs/Odometry) for the current longitudinal speed used by the adaptive lookahead and speed scheduling.

Configuration

Parameters are loaded from config/params.yaml under the namespace action/pure_pursuit_node/ros__parameters.

Parameters are read once in on_configure. To change them at runtime, transition the lifecycle node back through cleanup → configure (which reloads config/params.yaml), as with the other action nodes.

Topics / frames

Parameter	Type	Default	Description
`controller_status_topic`	string	`"controller_status"`	Topic for the `ControllerStatus` telemetry
`base_frame`	string	`"base_footprint"`	Frame stamped on published Ackermann commands
`rear_axle_frame`	string	`"rear_axle"`	Frame the pure-pursuit geometry and tracking error are computed in; also one end of the TF wheelbase measurement
`front_axle_frame`	string	`"front_axle"`	Other end of the TF wheelbase measurement
`standby_msg`	string	`"standby"`	Behaviour string that triggers standby output

Adaptive lookahead

Parameter	Type	Default	Description
`lookahead_distance`	double	`5.0`	Maximum lookahead distance (m)
`min_lookahead_distance`	double	`2.0`	Minimum lookahead distance (m)
`lookahead_time`	double	`1.5`	Time-headway: `ld = lookahead_time · speed`, clamped to min/max (s)
`curvature_lookahead_gain`	double	`2.0`	Shrinks lookahead in curves: `ld_eff = ld / (1 + gain·\|κ\|)`
`speed_lookahead_distance`	double	`1.0`	Minimum distance ahead used to sample target speed (m)
`speed_lookahead_time`	double	`2.0`	Time-headway for the (decoupled, longer) speed sample horizon (s)

Steering & speed

Parameter	Type	Default	Description
`steering_angle_gain`	double	`1.0`	Gain on the pure-pursuit steering output
`max_steering_angle`	double	`0.5`	Maximum steering magnitude (rad)
`max_steering_rate`	double	`1.0`	Steering slew-rate limit (rad/s)
`max_speed` / `min_speed`	double	`5.0` / `0.0`	Commanded speed bounds while tracking (m/s)
`max_lateral_accel`	double	`2.5`	Cornering-speed budget: `v ≤ sqrt(a_lat/\|κ\|)` (m/s²)
`max_accel` / `max_decel`	double	`1.5` / `3.0`	Command accel/decel slew limits (m/s²)

Low-speed cross-track blend (Stanley)

Parameter	Type	Default	Description
`enable_stanley_blend`	bool	`false`	Blend a cross-track feedback term into steering at low speed
`stanley_gain`	double	`0.5`	Cross-track feedback gain `k_e`
`stanley_softening`	double	`1.0`	Softening constant `k_soft` (avoids blow-up near zero speed)
`stanley_speed_threshold`	double	`2.0`	Blend weight ramps from 1 (at 0) to 0 at this speed (m/s)

Disengage monitor

Parameter	Type	Default	Description
`enable_disengage`	bool	`true`	Enable the tracking-threshold disengage monitor
`max_cross_track_error`	double	`1.5`	Cross-track error that (sustained) trips a disengage (m)
`max_heading_error`	double	`0.6`	Heading error that (sustained) trips a disengage (rad)
`disengage_debounce_sec`	double	`0.5`	How long the error must be exceeded before tripping (s)
`disengage_latch`	bool	`false`	`true` = stay disengaged until reconfigured; `false` = auto-recover
`disengage_speed`	double	`0.0`	Safe speed commanded when no valid lookahead point exists (m/s)

Standby / misc

Parameter	Type	Default	Description
`standby_speed`	double	`-0.5`	Speed commanded during standby (m/s)
`standby_steering`	double	`0.0`	Steering commanded during standby (rad)
`control_rate_hz`	double	`20.0`	Control publish rate (Hz)
`wheelbase_fallback`	double	`2.5667`	Fallback wheelbase if the TF lookup fails (m)
`idle_timeout_sec`	double	`2.0`	Time since last trajectory before declaring idle (s)
`invert_steering`	bool	`true`	Invert steering sign — `true` means positive angle = clockwise
`disable_standby`	bool	`false`	Bypass standby and track even when `standby_msg` is received

Algorithm Details

File truncated at 100 lines see the full file

CHANGELOG

No CHANGELOG found.

Package Dependencies

Deps	Name
	ament_cmake
	wato_test
	rclcpp
	rclcpp_lifecycle
	behaviour_msgs
	geometry_msgs
	nav_msgs
	std_msgs
	ackermann_msgs
	tf2
	tf2_ros
	tf2_geometry_msgs
	wato_trajectory_msgs

System Dependencies

No direct system dependencies.

Dependant Packages

Name	Deps
action_bringup

Launch files

No launch files found

Messages

No message files found.

Services

No service files found

Plugins

No plugins found.

Recent questions tagged `ackermann_pure_pursuit` at Robotics Stack Exchange

API Docs Browse Code Wiki

No version for distro noetic showing jazzy. Known supported distros are highlighted in the buttons above.

ackermann_pure_pursuit package from wato_monorepo repo

ackermann_pure_pursuit action_bringup freeroam_planner global_planning lattice_planning lattice_planning_markers lattice_planning_msgs model_predictive_control mpc_controller osqp_eigen_vendor trajectory_planner wato_trajectory_msgs infrastructure_bringup tf_static_relay vision_msgs_markers wato_lifecycle_manager ackermann_mux camera_calib lidar_imu_calib lidar_lidar_calib can_state_estimator dummy_ackermann eve_description interfacing_bringup joystick_interfacing lidar_aggregator oscc_interfacing oscc_mux pid_control pid_msgs roscco_msg sensor_interfacing topic_healthchecker attribute_assigner bevfusion cuda_bevfusion_vendor depth_estimation feature_extraction patchworkpp patchworkpp_vendor perception_bringup perception_utils spatial_association bytetrack_cpp_vendor track_viz_2d tracking traffic_light_detection carla_bringup carla_common carla_control carla_lifecycle carla_localization carla_msgs carla_perception carla_pygame carla_ros_bridge carla_sample_description carla_scenarios carla_teleop simulation_bringup wato_test behaviortree_ros2_vendor behaviour behaviour_markers behaviour_msgs costmap costmap_markers costmap_msgs eidos eidos_msgs eidos_tools eidos_transform lanelet_markers lanelet_msgs lidar_localization prediction world_model world_model_markers world_model_msgs world_modeling_bringup

ROS Distro
jazzy

API Docs
Browse Code
Wiki

Package Summary

Version	0.1.0
License	Apache 2.0
Build type	AMENT_CMAKE
Use	RECOMMENDED

Repository Summary

Description
Checkout URI	https://github.com/WATonomous/wato_monorepo.git
VCS Type	git
VCS Version	main
Last Updated	2026-10-15
Dev Status	DEVELOPED
Released	UNRELEASED
Contributing	Help Wanted (-) Good First Issues (-) Pull Requests to Review (-)

Package Description

Pure pursuit controller for ackermann vehicles

Maintainers

WATonomous

Authors

No additional authors.