Trajectory Follower Nodes

Purpose

Generate control commands to follow a given Trajectory.

Design

This is a node of the functionalities implemented in the controller class derived from trajectory_follower_base package. It has instances of those functionalities, gives them input data to perform calculations, and publishes control commands.

By default, the controller instance with the Controller class as follows is used.

@startuml
package trajectory_follower_base {
abstract class LateralControllerBase {
longitudinal_sync_data_

    virtual isReady(InputData)
    virtual run(InputData)
    sync(LongitudinalSyncData)
    reset()

}
abstract class LongitudinalControllerBase {
lateral_sync_data_

    virtual isReady(InputData)
    virtual run(InputData)
    sync(LateralSyncData)
    reset()

}

struct InputData {
trajectory
odometry
steering
accel
}
struct LongitudinalSyncData {
is_steer_converged
}
struct LateralSyncData {
}
}

package mpc_lateral_controller {
class MPCLateralController {
isReady(InputData) override
run(InputData) override
}
}
package pure_pursuit {
class PurePursuitLateralController {
isReady(InputData) override
run(InputData) override
}
}
package pid_longitudinal_controller {
class PIDLongitudinalController {
isReady(InputData) override
run(InputData) override
}
}

package trajectory_follower_node {
class Controller {
longitudinal_controller_
lateral_controller_
onTimer()
createInputData(): InputData
}
}

MPCLateralController --|> LateralControllerBase
PurePursuitLateralController --|> LateralControllerBase
PIDLongitudinalController --|> LongitudinalControllerBase

LateralSyncData --> LongitudinalControllerBase
LateralSyncData --> LateralControllerBase
LongitudinalSyncData --> LongitudinalControllerBase
LongitudinalSyncData --> LateralControllerBase
InputData ..> LateralControllerBase
InputData ..> LongitudinalControllerBase

LateralControllerBase --o Controller
LongitudinalControllerBase --o Controller
InputData ..> Controller
@enduml

The process flow of Controller class is as follows.

```cpp // 1. create input data const auto input_data = createInputData(*get_clock()); if (!input_data) { return; }

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