PROS-Car

Car Type

Type	Description
A	Rear-wheel drive, front-wheel steering
B	Rear-wheel drive
C	Four-wheel drive with robot arm
D	Mecanum wheel

Workflow Diagram

Deprecated Warning

The image in this repository pros_car is deprecated. Use pros_ai_image instead.

The Dockerfile here is to test new feature based on ghcr.io/otischung/pros_ai_image:latest.

Feature

The docker image in this project has the following 4 features shown above.

• Keyboard
• Car_<A,B,C,D>_serial_reader
• Car_<A,B,C,D>_serial_writer
• arm_reader
• arm_writer

The Link to the other Features

pros_app contains the following features.

• RPLidar
• Camera
• SLAM

pros_AI contains Car_B_AI.

pros_AI_image is the repository which creates the entire base docker image.

Get Started

Run the Docker Image

We've written the car_control.sh shell script to run the image.

Environment Variables

These environment variables are defined in .env.

ROS Domain ID

You may change the ID number to divide other ROS environments.

export ROS_DOMAIN_ID=1

Setting for the Speed of the Car

You can change the speed of your car via the Linux environment variable WHEEL_SPEED using the unit rad/s.

export WHEEL_SPEED=3

ROS2 Services

Code

• Dockerfile
  • You may change the ID number to divide other ROS environments.

ENV ROS_DOMAIN_ID=1

• Car<A~D>_serial_writer.py
  • Send the signals to jetson orin nano, receive the signals from Car<A~D>_keyboard.py.
• Car<A~D>_keyboard.py
• Send the signal to Car<A~D>_serial_writer.py, in target_vel, index 0 is the left wheel, index 1 is the right wheel.
• If the car type is four-wheel drive, we have two lists, one contains self._vel and self._vel2 and the other contains self._vel3 and self._vel4.

# two wheels:
target_vel = [self._vel, self._vel]

# four wheels 
target_vel = [self._vel, self._vel2] 
target_vel = [self._vel3, self._vel4] 
# These two target velocities are sent through different topics

• env.py

  • When we set the USB port, if we run Car<A~D>_serial_writer.py and the terminal shows that “cannot find the desired USB port”, then you have to edit this script or check out the USB port on the car device.
  • You can run ls /dev/ttyUSB* to check your USB port number. (if there doesn’t appear any USB devices, you must exit docker, and check the USB port on the car, ttyUSB<0~3> number depends on the inserted order)
  • We've defined the name of the soft link for usb_front_wheel, usb_rear_wheel, and usb_lidar in pros_app. You may also use these rules in this container.
  • Referene

• car_models.py

  • For all received data-class types, which the behavior is like struct in C/C++.

• Run the car (open two terminals)

  • Use w a s d or other keys to control the car.
  • Press z to stop the car.
    • Note: The car will always go forward and then stop slowly in any case. This is a bug in the C++ program controlling the ESP32.
  • Press q to exit the keyboard.py.

  ros2 run pros_car_py car<A~D>_serial_writer.py

  ros2 run pros_car_py car<A~D>_keyboard.py