Cosimulation with ROS

Overview

DYNO includes a set of ROS packages to facilitate autonomous driving simulations. These packages allow for easy interfacing of the simulation with ROS applications and the postprocessing of simulation results collected in Rosbag format. At the time of writing, only simple obstacle avoidance scenarios are available for simulation in ROS.

Important

It is important to note that the ROS interface from DYNO pre-dates and differs from the Chrono::ROS module available in Project Chrono. All parameters and interfaces listed in the following sections strictly apply to the DYNO ROS packages, and all postprocessing tools included with DYNO only accept Rosbags generated using the DYNO simulation nodes.

Available packages

• dyno_interfaces: interfaces (messages, services, etc.) for DYNO simulations.

• dyno_simulation: nodes to interface DYNO with ROS.

• dyno_utilities: recording and postprocessing utilities for DYNO ROS packages.

Nodes

Cosimulation node

Native simulation node

The native simulation node allows for direct simulation inside a ROS node. It provides the best performance, limiting the delays and bandwidth requirements that come with transferring large messages like point clouds and images. On the other hand, native nodes require all simulation to happen on the same machine running ROS.

The vehicle models implemented in DYNO (and, more broadly, the vast majority of the vehicle models in Chrono::Vehicle) do not support direct speed or steering angle commands. The native simulation node implements its own speed and steering controllers achieving closed-loop control through two separate PID controllers to bridge this gap. The controller gains can be tuned through the native node parameters, and tick at the same rate as the native node.

Negative simulation rates mean the simulator will run as fast as possible.

Parameters

Native simulation node parameters

Name	Type	Description	Default value
options	string	Path to the simulation options file
rates.transforms	double	Rate at which the transforms are published to the TF tree	1000.0
rates.odometry	double	Rate at which the ideal odometry data is published.	100.0
rates.imu	double	Rate at which the ideal inertial measurement unit data is published.	100.0
rates.pointcloud	double	Rate at which the LiDAR point cloud data is published.	10.0
rates.image	double	Rate at which the camera image and info are published.	15.0
rates.controllers	double	Rate at which the speed and steering controllers are ticking.	200.0
controllers.speed.gains.proportional	double	Proportional gain for the speed controller.	0.0002
controllers.speed.gains.integral	double	Integral gain for the speed controller	0.11
controllers.speed.gains.derivative	double	Derivative gain for the speed controller.	0.0
controllers.speed.setpoint.ramp.enabled	bool	Whether or not to ramp the speed setpoint.	true
controllers.speed.setpoint.ramp.magnitude	double	Maximum speed setpoint change between two consecutive controller ticks.	0.05
controllers.speed.limit.integral.enabled	bool	Whether or not the speed controller integral term limiter is enabled.	true
controllers.speed.limit.integral.magnitude	double	Maximum magnitude for the speed controller integral term.	0.3
controllers.steering.gains.proportional	double	Proportional gain for the steering controller.	0.0002
controllers.steering.gains.integral	double	Integral gain for the steering controller	0.11
controllers.steering.gains.derivative	double	Derivative gain for the steering controller.	0.0
controllers.steering.setpoint.ramp.enabled	bool	Whether or not to ramp the steering setpoint.	true
controllers.steering.setpoint.ramp.magnitude	double	Maximum steering setpoint change between two consecutive controller ticks.	0.05
controllers.steering.limit.integral.enabled	bool	Whether or not the steering controller integral term limiter is enabled.	true
controllers.steering.limit.integral.magnitude	double	Maximum magnitude for the steering controller integral term.	0.3
obstacles.message	string	Obstacles message type format.	none

Subscriptions

Native simulation node subscriptions

Topic	Message type	Description
joystick/state	sensor_msgs/msg/Joy	Joystick state for overriding controls.
controls/drive	ackermann_msgs/msg/AckermannDriveStamped	Ackermann command to control the vehicle.

Publishers

Native simulation node publishers

Topic	Message type	Description
/clock	rosgraph_msgs/msg/Clock	Simulation time clock for synchronization.
sensors/inertial_navigation_system/odometry	nav_msgs/msg/Odometry	Ideal odometry from simulation.
sensors/inertial_navigation_system/imu	sensor_msgs/msg/Imu	Ideal inertial measurement unit output from simulation.
sensors/lidar/points	sensor_msgs/msg/PointCloud2	Simulated LiDAR sensor scans.
sensors/camera/mono/image/raw	sensor_msgs/msg/Image	Uncompressed simulated monocular RGB camera image.
sensors/camera/mono/image/info	sensor_msgs/msg/CameraInfo	Simulated camera intrinsics info.
sensors/steering/angle	std_msgs/msg/Float64	Average front axle steering angle (expressed in radians).
controls/throttle	std_msgs/msg/Float64	Normalized throttle effort.
controls/brake	std_msgs/msg/Float64	Normalized brake effort.
controls/steering	std_msgs/msg/Float64	Normalized steering effort.
models/joints/steering	sensor_msgs/msg/JointState	Front axle wheels joint state used for visualization in RViz.