AWSIM Vehicle
Info
AWSIM Vehicle Dynamics is mostly functional, but still under development.
Sample Vehicle - Lexus RX450h
AWSIM project includes a Lexus RX450h vehicle model. Prefab path is
AWSIM\Assets\AWSIM\Prefabs\VehiclesWithSensor\Lexus RX450h 2015 Sample Sensor.prefab
Vehicle Dynamics Concept
The concept for VehicleDynamics is suitable for Autoware's autoware_auto_control_msgs/AckermannControlCommand and autoware_auto_vehicle_msgs/GearCommand message interface usage.
Supported features:
- Longitudinal control by acceleration (m/s^2)
- Lateral control by two-wheel model
- Yaw, roll and pitch controlled by physics engine
- Mass-spring-damper suspension model
- Logical, not mechanical, automatic gears change
Required vehicle parameters
Info
In general, measuring the moment of inertia is not easy, and past papers published by NHTSA are helpful.
Measured Vehicle Inertial Parameters - NHTSA 1998
| Parameter | Value | unit |
|---|---|---|
| mass | 1500 | kg |
| wheel base | 2.5 | m |
| tread width | Ft : 1.8, Rr : 1.8 | m |
| center of mass position | x : 0, y : 0.5, z : 0 | m |
| moment of inertia | yaw : 2000, roll : 2000, pitch : 700 | kgm^2 |
| spring rate | Ft : 55000, Rr : 48000 | N |
| damper rate | Ft : 3000, Rr : 2500 | N/s |
| suspension stroke | Ft : 0.2, Rr 0.2 | m |
| wheel radius | 0.365 | m |
Vehicle control scripts
Scripts that simulate and support the car's behavior are placed under AWSIM/Assets/AWSIM/Scripts/Vehicles directory.
| script | feature |
|---|---|
| Vehicle.cs | Vehicle dynamics core class |
| VehicleKeyboardInput.cs | Input control by keyboard |
| VehicleRosInput.cs | Input control by ROS |
| VehicleVisualEffect.cs` | Visual effects (e.g. brake and turn signals) |
Vehicle API
The following section describes the API of Vehicle.cs script.
Input API
Check
See also VehicleKeyboardInput.cs, VehicleRosInput.cs.
| input API | type | feature |
|---|---|---|
| Vehicle.AccelerationInput | float | Acceleration input (m/s^2). On the plane, output the force that will result in this acceleration. On a slope, it is affected by the slope resistance, so it does not match the input. |
| Vehicle.SteerAngleInput | float | Vehicle steering input (degree). Negative steers left, positive right |
| Vehicle.AutomaticShiftInput | enumeration | Vehicle gear shift input (AT). Values: PARKING, REVERSE, NEUTRAL, DRIVE. |
| Vehicle.SignalInput | enumeration | Vehicle turn signal input. Values: NONE, LEFT, RIGHT, HAZARD. |
Output API
| output API | type | feature |
|---|---|---|
| Vehicle.LocalAcceleration | Vector3 | Acceleration(m/s^2) in the local coordinate system of the vehicle. |
| Vehicle.Speed | float | Vehicle speed (m/s). |
| Vehicle.SteerAngle | float | Vehicle steering angle (degree). |
| Vehicle.Signal | enumeration | Vehicle turn signal. |
| Vehicle.Velocity | Vector3 | Vehicle velocity (m/s) |
| Vehicle.LocalVelcoity | Vector3 | Vehicle local velocity (m/s) |
| Vehicle.AngularVelocity | Vector3 | Vehicle angular velocity (rad/s) |
ROS2 Control Topics
VehicleRosInput subscribes to these topics and applies them to the Vehicle
| topic | msg | frame_id | hz | QoS |
|---|---|---|---|---|
/control/command/turn_indicators_cmd |
autoware_auto_vehicle_msgs/TurnIndicatorsCommand |
none | 10 |
Reliable,TransientLocal,KeepLast/1 |
/control/command/hazard_lights_cmd |
autoware_auto_vehicle_msgs/HazardLightsCommand |
none | 10 |
Reliable,TransientLocal,KeepLast/1 |
/control/command/control_cmd |
autoware_auto_control_msgs/AckermannControlCommand |
none | 60 |
Reliable,TransientLocal,KeepLast/1 |
/control/command/gear_cmd |
autoware_auto_vehicle_msgs/GearCommand |
none | 10 |
Reliable,TransientLocal,KeepLast/1 |
/control/command/emergency_cmd |
tier4_vehicle_msgs/msg/VehicleEmergencyStamped |
none | 60 |
Reliable,TransientLocal,KeepLast/1 |