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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/initialpose [geometry_msgs/msg/PoseWithCovarianceStamped] : for initial pose
  • input/ackermann_control_command [autoware_control_msgs/msg/Control] : target command to drive a vehicle
  • input/manual_ackermann_control_command [autoware_control_msgs/msg/Control] : manual target command to drive a vehicle (used when control_mode_request = Manual)
  • input/gear_command [autoware_vehicle_msgs/msg/GearCommand] : target gear command.
  • input/manual_gear_command [autoware_vehicle_msgs/msg/GearCommand] : target gear command (used when control_mode_request = Manual)
  • input/turn_indicators_command [autoware_vehicle_msgs/msg/TurnIndicatorsCommand] : target turn indicator command
  • input/hazard_lights_command [autoware_vehicle_msgs/msg/HazardLightsCommand] : target hazard lights command
  • input/control_mode_request [tier4_vehicle_msgs::srv::ControlModeRequest] : mode change for Auto/Manual driving

output#

  • /tf [tf2_msgs/msg/TFMessage] : simulated vehicle pose (base_link)
  • /output/odometry [nav_msgs/msg/Odometry] : simulated vehicle pose and twist
  • /output/steering [autoware_vehicle_msgs/msg/SteeringReport] : simulated steering angle
  • /output/control_mode_report [autoware_vehicle_msgs/msg/ControlModeReport] : current control mode (Auto/Manual)
  • /output/gear_report [autoware_vehicle_msgs/msg/ControlModeReport] : simulated gear
  • /output/turn_indicators_report [autoware_vehicle_msgs/msg/ControlModeReport] : simulated turn indicator status
  • /output/hazard_lights_report [autoware_vehicle_msgs/msg/ControlModeReport] : simulated hazard lights status

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 input/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_VEL
  • IDEAL_STEER_ACC
  • IDEAL_STEER_ACC_GEARED
  • DELAY_STEER_VEL
  • DELAY_STEER_ACC
  • DELAY_STEER_ACC_GEARED
  • DELAY_STEER_ACC_GEARED_WO_FALL_GUARD
  • DELAY_STEER_MAP_ACC_GEARED: applies 1D dynamics and time delay to the steering and acceleration commands. The simulated acceleration is determined by a value converted through the provided acceleration map. This model is valuable for an accurate simulation with acceleration deviations in a real vehicle.
  • LEARNED_STEER_VEL: launches learned python models. More about this here.

The following models receive ACTUATION_CMD generated from raw_vehicle_cmd_converter. Therefore, when these models are selected, the raw_vehicle_cmd_converter is also launched.

  • ACTUATION_CMD: This model only converts accel/brake commands and use steer command as it is.
  • ACTUATION_CMD_STEER_MAP: The steer command is converted to the steer rate command using the steer map.
  • ACTUATION_CMD_VGR: The steer command is converted to the steer rate command using the variable gear ratio.
  • ACTUATION_CMD_MECHANICAL: This model has mechanical dynamics and controller for that.

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 D_ST_A_G_WO_FG D_ST_M_ACC_G L_S_V A_C Default value unit
acc_time_delay double dead time for the acceleration input x x x x o o o o x x 0.1 [s]
steer_time_delay double dead time for the steering input x x x o o o o o x o 0.24 [s]
vel_time_delay double dead time for the velocity input x x x o x x x x x x 0.25 [s]
acc_time_constant double time constant of the 1st-order acceleration dynamics x x x x o o o o x x 0.1 [s]
steer_time_constant double time constant of the 1st-order steering dynamics x x x o o o o o x o 0.27 [s]
steer_dead_band double dead band for steering angle x x x o o o o x x o 0.0 [rad]
vel_time_constant double time constant of the 1st-order velocity dynamics x x x o x x x x x x 0.5 [s]
vel_lim double limit of velocity x x x o o o o o x x 50.0 [m/s]
vel_rate_lim double limit of acceleration x x x o o o o o x x 7.0 [m/ss]
steer_lim double limit of steering angle x x x o o o o o x o 1.0 [rad]
steer_rate_lim double limit of steering angle change rate x x x o o o o o x o 5.0 [rad/s]
steer_bias double bias for steering angle x x x o o o o o x o 0.0 [rad]
debug_acc_scaling_factor double scaling factor for accel command x x x x o o o x x x 1.0 [-]
debug_steer_scaling_factor double scaling factor for steer command x x x x o o o x x x 1.0 [-]
acceleration_map_path string path to csv file for acceleration map which converts velocity and ideal acceleration to actual acceleration x x x x x x x o x x - [-]
model_module_paths string path to a python module where the model is implemented x x x x x x x x o x - [-]
model_param_paths string path to the file where model parameters are stored (can be empty string if no parameter file is required) x x x x x x x x o x - [-]
model_class_names string name of the class that implements the model x x x x x x x x o x - [-]

Note: Parameters model_module_paths, model_param_paths, and model_class_names need to have the same length.

The acceleration_map is used only for DELAY_STEER_MAP_ACC_GEARED and it shows the acceleration command on the vertical axis and the current velocity on the horizontal axis, with each cell representing the converted acceleration command that is actually used in the simulator's motion calculation. Values in between are linearly interpolated.

Example of acceleration_map.csv

default,  0.00,  1.39,  2.78,  4.17,  5.56,  6.94,  8.33,  9.72, 11.11, 12.50, 13.89, 15.28, 16.67
-4.0,    -4.40, -4.36, -4.38, -4.12, -4.20, -3.94, -3.98, -3.80, -3.77, -3.76, -3.59, -3.50, -3.40
-3.5,    -4.00, -3.91, -3.85, -3.64, -3.68, -3.55, -3.42, -3.24, -3.25, -3.00, -3.04, -2.93, -2.80
-3.0,    -3.40, -3.37, -3.33, -3.00, -3.00, -2.90, -2.88, -2.65, -2.43, -2.44, -2.43, -2.39, -2.30
-2.5,    -2.80, -2.72, -2.72, -2.62, -2.41, -2.43, -2.26, -2.18, -2.11, -2.03, -1.96, -1.91, -1.85
-2.0,    -2.30, -2.24, -2.12, -2.02, -1.92, -1.81, -1.67, -1.58, -1.51, -1.49, -1.40, -1.35, -1.30
-1.5,    -1.70, -1.61, -1.47, -1.46, -1.40, -1.37, -1.29, -1.24, -1.10, -0.99, -0.83, -0.80, -0.78
-1.0,    -1.30, -1.28, -1.10, -1.09, -1.04, -1.02, -0.98, -0.89, -0.82, -0.61, -0.52, -0.54, -0.56
-0.8,    -0.96, -0.90, -0.82, -0.74, -0.70, -0.65, -0.63, -0.59, -0.55, -0.44, -0.39, -0.39, -0.35
-0.6,    -0.77, -0.71, -0.67, -0.65, -0.58, -0.52, -0.51, -0.50, -0.40, -0.33, -0.30, -0.31, -0.30
-0.4,    -0.45, -0.40, -0.45, -0.44, -0.38, -0.35, -0.31, -0.30, -0.26, -0.30, -0.29, -0.31, -0.25
-0.2,    -0.24, -0.24, -0.25, -0.22, -0.23, -0.25, -0.27, -0.29, -0.24, -0.22, -0.17, -0.18, -0.12
 0.0,     0.00,  0.00, -0.05, -0.05, -0.05, -0.05, -0.08, -0.08, -0.08, -0.08, -0.10, -0.10, -0.10
 0.2,     0.16,  0.12,  0.02,  0.02,  0.00,  0.00, -0.05, -0.05, -0.05, -0.05, -0.08, -0.08, -0.08
 0.4,     0.38,  0.30,  0.22,  0.25,  0.24,  0.23,  0.20,  0.16,  0.16,  0.14,  0.10,  0.05,  0.05
 0.6,     0.52,  0.52,  0.51,  0.49,  0.43,  0.40,  0.35,  0.33,  0.33,  0.33,  0.32,  0.34,  0.34
 0.8,     0.82,  0.81,  0.78,  0.68,  0.63,  0.56,  0.53,  0.48,  0.43,  0.41,  0.37,  0.38,  0.40
 1.0,     1.00,  1.08,  1.01,  0.88,  0.76,  0.69,  0.66,  0.58,  0.54,  0.49,  0.45,  0.40,  0.40
 1.5,     1.52,  1.50,  1.38,  1.26,  1.14,  1.03,  0.91,  0.82,  0.67,  0.61,  0.51,  0.41,  0.41
 2.0,     1.80,  1.80,  1.64,  1.43,  1.25,  1.11,  0.96,  0.81,  0.70,  0.59,  0.51,  0.42,  0.42

acceleration_map

ACTUATION_CMD model#

The simple_planning_simulator usually operates by receiving Control commands, but when the ACTUATION_CMD* model is selected, it receives Actuation commands instead of Control commands. This model can simulate the motion using the vehicle command that is actually sent to the real vehicle. Therefore, when this model is selected, the raw_vehicle_cmd_converter is also launched. Please refer to the actuation_cmd_sim.md for more details.

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.

Example of LEARNED_STEER_VEL model#

We created a few basic models to showcase how LEARNED_STEER_VEL works.

  1. Install a library that contains basic Python models. (branch: v0.1_autoware)

  2. In a file src/vehicle/sample_vehicle_launch/sample_vehicle_description/config/simulator_model.param.yaml set vehicle_model_type to LEARNED_STEER_VEL. In the same file set the following parameters. These models are for testing and do not require any parameter file.

model_module_paths:
  [
    "control_analysis_pipeline.autoware_models.vehicle.kinematic",
    "control_analysis_pipeline.autoware_models.steering.steer_example",
    "control_analysis_pipeline.autoware_models.drive.drive_example",
  ]
model_param_paths: ["", "", ""]
model_class_names: ["KinematicModel", "SteerExample", "DriveExample"]

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.

(Caveat) Pitch calculation#

Ego vehicle pitch angle is calculated in the following manner.

pitch calculation

NOTE: driving against the line direction (as depicted in image's bottom row) is not supported and only shown for illustration purposes.

Error detection and handling#

The only validation on inputs being done is testing for a valid vehicle model type.

Security considerations#

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