Torque Vectoring

ROS 2 torque-vectoring control software for a four-wheel vehicle. The project contains a reusable C++ control library, a ROS 2 node, reference generators, high- and low-level controllers, traction control, and a Python TCP bridge for connecting ROS 2 to Simulink.

Project Layout

• torque-vectoring/: ROS 2 package and C++ implementation
• torque-vectoring/include/: public headers and data structures
• torque-vectoring/src/: library and ROS 2 node sources
• torque-vectoring/test/: GoogleTest sources
• tcp_to_ros.py: TCP bridge between Simulink and ROS 2

Requirements

• ROS 2 with rclcpp, std_msgs, and geometry_msgs
• C++17 compiler
• CMake 3.16 or newer
• Python 3 with numpy and rclpy
• A TCP client such as Simulink for the bridge, if required

Build

Source ROS 2 in a new terminal, then build from the repository root:

source /opt/ros/<ros-distro>/setup.bash
colcon build --symlink-install
source install/setup.bash

The package can also be configured directly with CMake when the required ROS 2 environment is available:

cmake -S torque-vectoring -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build

Run

Start the torque-vectoring node:

source install/setup.bash
ros2 run torque_vectoring torque_vectoring_node

Start the Simulink bridge in another terminal:

source /opt/ros/<ros-distro>/setup.bash
python3 tcp_to_ros.py

The bridge listens on all interfaces. Configure the Simulink side to connect to:

• TCP port 20000: Simulink to ROS 2 input data
• TCP port 20001: ROS 2 to Simulink wheel-torque output

ROS 2 Interface

Subscribed topics

Topic	Type	Meaning
/vehicle/throttle	std_msgs/msg/Float64	Driver throttle command
/vehicle/steering	std_msgs/msg/Float64	Driver steering command
/vehicle/yaw_rate	std_msgs/msg/Float64	Measured yaw rate
/vehicle/velocity	geometry_msgs/msg/Vector3	Vehicle velocity; x and y are used
/vehicle/acceleration	geometry_msgs/msg/Vector3	Vehicle acceleration; x and y are used
/vehicle/slip_rl	std_msgs/msg/Float64	Rear-left slip percentage
/vehicle/slip_rr	std_msgs/msg/Float64	Rear-right slip percentage

Published topics

Topic	Type	Meaning
/vehicle/wheel_torques	std_msgs/msg/Float64MultiArray	[rear_left_torque, rear_right_torque]
/vehicle/yaw_rate_reference	std_msgs/msg/Float64	Generated yaw-rate reference
/vehicle/sideslip_reference	std_msgs/msg/Float64	Generated sideslip reference
/vehicle/yaw_moment_request	std_msgs/msg/Float64	High-level yaw-moment request
/vehicle/total_torque_request	std_msgs/msg/Float64	Requested total torque

The node uses a 1 ms timer for its control loop. Slip values received by the C++ node are interpreted as percentages and converted to ratios.

TCP Bridge Protocol

Input packets on port 20000 are interpreted as native little-endian float64 values. The first value is a message flag:

Flag	Remaining values
0	throttle, steering
1	yaw_rate, velocity_x
2	velocity_x, velocity_y, acceleration_x, acceleration_y
3	slip_rl, slip_rr

Output packets on port 20001 contain two native float64 values in this order:

rear_left_torque, rear_right_torque

The bridge currently publishes its input values on the ROS topics listed above and sends only the first two values of /vehicle/wheel_torques back to the connected TCP client.

Tests

GoogleTest source files are included under torque-vectoring/test/. The test target is currently commented out in torque-vectoring/CMakeLists.txt, so the tests are not registered with CMake or ctest yet.

After enabling the test target, run the tests with:

cd build
gctest --output-on-failure

License

MIT