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docs(trajectory_follower_node): add missing parameter description (ti…
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…er4#476)

* update mpc doc

Signed-off-by: Takamasa Horibe <horibe.takamasa@gmail.com>

* apply format

Signed-off-by: Takamasa Horibe <horibe.takamasa@gmail.com>

* fix typo

Signed-off-by: Takamasa Horibe <horibe.takamasa@gmail.com>
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TakaHoribe authored and boyali committed Oct 19, 2022
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32 changes: 18 additions & 14 deletions control/trajectory_follower_nodes/design/lateral_controller-design.md
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Expand Up @@ -17,7 +17,7 @@ when following a path.
- How does it work? -->
The node uses an implementation of linear model predictive control (MPC) for accurate path tracking.
The MPC uses a model of the vehicle to simulate the trajectory resulting from the control command.
The optimization of the control command is formulated as a Quadradic Program (QP).
The optimization of the control command is formulated as a Quadratic Program (QP).

These functionalities are implemented in the `trajectory_follower` package
(see @subpage trajectory_follower-mpc-design)
Expand All @@ -42,19 +42,23 @@ Output
The default parameters defined in `param/lateral_controller_defaults.yaml` are adjusted to the
AutonomouStuff Lexus RX 450h for under 40 km/h driving.

| Name | Type | Description | Default value |
| :-------------------------------- | :----- | :------------------------------------------------------------------------------------------------------------------------------------------------ | :------------ |
| show_debug_info | bool | display debug info | false |
| ctrl_period | double | control period [s] | 0.03 |
| traj_resample_dist | double | distance of waypoints in resampling [m] | 0.1 |
| enable_path_smoothing | bool | path smoothing flag. This should be true when uses path resampling to reduce resampling noise. | true |
| path_filter_moving_ave_num | int | number of data points moving average filter for path smoothing | 35 |
| path_smoothing_times | int | number of times of applying path smoothing filter | 1 |
| curvature_smoothing_num_ref_steer | double | index distance of points used in curvature calculation for reference steer command: p(i-num), p(i), p(i+num). larger num makes less noisy values. | 35 |
| curvature_smoothing_num_traj | double | index distance of points used in curvature calculation for trajectory: p(i-num), p(i), p(i+num). larger num makes less noisy values. | 1 |
| steering_lpf_cutoff_hz | double | cutoff frequency of lowpass filter for steering output command [hz] | 3.0 |
| admissible_position_error | double | stop vehicle when following position error is larger than this value [m]. | 5.0 |
| admissible_yaw_error_rad | double | stop vehicle when following yaw angle error is larger than this value [rad]. | 1.57 |
| Name | Type | Description | Default value |
| :------------------------------------------- | :----- | :------------------------------------------------------------------------------------------------------------------------------------------------ | :------------ |
| show_debug_info | bool | display debug info | false |
| ctrl_period | double | control period [s] | 0.03 |
| traj_resample_dist | double | distance of waypoints in resampling [m] | 0.1 |
| enable_path_smoothing | bool | path smoothing flag. This should be true when uses path resampling to reduce resampling noise. | true |
| path_filter_moving_ave_num | int | number of data points moving average filter for path smoothing | 35 |
| path_smoothing_times | int | number of times of applying path smoothing filter | 1 |
| curvature_smoothing_num_ref_steer | double | index distance of points used in curvature calculation for reference steer command: p(i-num), p(i), p(i+num). larger num makes less noisy values. | 35 |
| curvature_smoothing_num_traj | double | index distance of points used in curvature calculation for trajectory: p(i-num), p(i), p(i+num). larger num makes less noisy values. | 1 |
| steering_lpf_cutoff_hz | double | cutoff frequency of lowpass filter for steering output command [hz] | 3.0 |
| admissible_position_error | double | stop vehicle when following position error is larger than this value [m]. | 5.0 |
| admissible_yaw_error_rad | double | stop vehicle when following yaw angle error is larger than this value [rad]. | 1.57 |
| stop_state_entry_ego_speed <sup>\*1</sup> | double | threshold value of the ego vehicle speed used to the stop state entry condition | 0.0 |
| stop_state_entry_target_speed <sup>\*1</sup> | double | threshold value of the target speed used to the stop state entry condition | 0.0 |

(\*1) To prevent unnecessary steering movement, the steering command is fixed to the previous value in the stop state.

### MPC algorithm

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