simple_planning_simulator#
Purpose / Use cases#
This node simulates the vehicle motion for a vehicle command in 2D using a simple vehicle model.
Design#
The purpose of this simulator is for the integration test of planning and control modules. This does not simulate sensing or perception, but is implemented in pure c++ only and works without GPU.
Assumptions / Known limits#
- It simulates only in 2D motion.
- It does not perform physical operations such as collision and sensing, but only calculates the integral results of vehicle dynamics.
Inputs / Outputs / API#
input
- input/vehicle_control_command [autoware_auto_msgs/msg/VehicleControlCommand] : target command to drive a vehicle.
- input/ackermann_control_command [autoware_auto_msgs/msg/AckermannControlCommand] : target command to drive a vehicle.
- input/vehicle_state_command [autoware_auto_msgs/msg/VehicleStateCommand] : target state command (e.g. gear).
- /initialpose [geometry_msgs/msg/PoseWithCovarianceStamped] : for initial pose
output
- /tf [tf2_msgs/msg/TFMessage] : simulated vehicle pose (base_link)
- /vehicle/vehicle_kinematic_state [autoware_auto_msgs/msg/VehicleKinematicState] : simulated kinematic state (defined in CoM)
- /vehicle/state_report [autoware_auto_msgs/msg/VehicleStateReport] : current vehicle state (e.g. gear, mode, etc.)
Inner-workings / Algorithms#
Common Parameters#
| Name | Type | Description | Default value |
|---|---|---|---|
| simulated_frame_id | string | set to the child_frame_id in output tf | "base_link" |
| origin_frame_id | string | set to the frame_id in output tf | "odom" |
| initialize_source | string | If "ORIGIN", the initial pose is set at (0,0,0). If "INITIAL_POSE_TOPIC", node will wait until the /initialpose topic is published. |
"INITIAL_POSE_TOPIC" |
| add_measurement_noise | bool | If true, the Gaussian noise is added to the simulated results. | true |
| pos_noise_stddev | double | Standard deviation for position noise | 0.01 |
| rpy_noise_stddev | double | Standard deviation for Euler angle noise | 0.0001 |
| vel_noise_stddev | double | Standard deviation for longitudinal velocity noise | 0.0 |
| angvel_noise_stddev | double | Standard deviation for angular velocity noise | 0.0 |
| steer_noise_stddev | double | Standard deviation for steering angle noise | 0.0001 |
Vehicle Model Parameters#
vehicle_model_type options
IDEAL_STEER_VELIDEAL_STEER_ACCIDEAL_STEER_ACC_GEAREDDELAY_STEER_VELDELAY_STEER_ACCDELAY_STEER_ACC_GEARED
The IDEAL model moves ideally as commanded, while the DELAY model moves based on a 1st-order with time delay model. The STEER means the model receives the steer command. The VEL means the model receives the target velocity command, while the ACC model receives the target acceleration command. The GEARED suffix means that the motion will consider the gear command: the vehicle moves only one direction following the gear.
The table below shows which models correspond to what parameters. The model names are written in abbreviated form (e.g. IDEAL_STEER_VEL = I_ST_V).
| Name | Type | Description | I_ST_V | I_ST_A | I_ST_A_G | D_ST_V | D_ST_A | D_ST_A_G | Default value | unit |
|---|---|---|---|---|---|---|---|---|---|---|
| acc_time_delay | double | dead time for the acceleration input | x | x | x | x | o | o | 0.1 | [s] |
| steer_time_delay | double | dead time for the steering input | x | x | x | o | o | o | 0.24 | [s] |
| vel_time_delay | double | dead time for the velocity input | x | x | x | o | x | x | 0.25 | [s] |
| acc_time_constant | double | time constant of the 1st-order acceleration dynamics | x | x | x | x | o | o | 0.1 | [s] |
| steer_time_constant | double | time constant of the 1st-order steering dynamics | x | x | x | o | o | o | 0.27 | [s] |
| vel_time_constant | double | time constant of the 1st-order velocity dynamics | x | x | x | o | x | x | 0.5 | [s] |
| vel_lim | double | limit of velocity | x | x | x | o | o | o | 50.0 | [m/s] |
| vel_rate_lim | double | limit of acceleration | x | x | x | o | o | o | 7.0 | [m/ss] |
| steer_lim | double | limit of steering angle | x | x | x | o | o | o | 1.0 | [rad] |
| steer_rate_lim | double | limit of steering angle change rate | x | x | x | o | o | o | 5.0 | [rad/s] |
Note: The steering/velocity/acceleration dynamics is modeled by a first order system with a deadtime in a delay model. The definition of the time constant is the time it takes for the step response to rise up to 63% of its final value. The deadtime is a delay in the response to a control input.
Default TF configuration#
Since the vehicle outputs odom->base_link tf, this simulator outputs the tf with the same frame_id configuration.
In the simple_planning_simulator.launch.py, the node that outputs the map->odom tf, that usually estimated by the localization module (e.g. NDT), will be launched as well. Since the tf output by this simulator module is an ideal value, odom->map will always be 0.
Error detection and handling#
The only validation on inputs being done is testing for a valid vehicle model type.
Security considerations#
References / External links#
This is originally developed in the Autoware.AI. See the link below.
https://github.com/Autoware-AI/simulation/tree/master/wf_simulator
Future extensions / Unimplemented parts#
- Improving the accuracy of vehicle models (e.g., adding steering dead zones and slip behavior)
- Cooperation with modules that output pseudo pointcloud or pseudo perception results
Related issues#
-
1142: Follow-up to #570 - Integrate simple_planning_simulator Into CI#