PCBV2

Mobile Robot — Engineering Thesis

Available languages: English | Polski

Design and software for a four-wheeled (tracked) mobile robot. Real-time firmware running on STM32H755, high-level control via ROS 2 Humble on NVIDIA Jetson Nano, custom motherboard designed in KiCad, and mechanical models for gearboxes and chassis.

Author: Błażej Kruszka, Nicolaus Copernicus University in Toruń, 2025–2026.

Architecture

gamepad  →  ROS 2 (Jetson)  →  UART 115200  →  STM32H755
                 │                                  │
                 └── /telemetry ← PI velocities ← DC encoders, PWM, A4988

• STM32 (CM7) — encoders, PI controllers, H-bridges (4× DC), stepper motors (4× A4988), UART protocol.
• ROS 2 — gamepad input handling, serial bridge, telemetry logger.
• PCB — custom motherboard for Nucleo-H755, 8 actuator channels, and sensor interfaces.

Repository Structure

No working notes, CubeIDE dumps, KiCad backups, videos, or external works are stored here.

Firmware (STM32)

Open the firmware/ directory in STM32CubeIDE (the dual-core project is named jakie_wyjscia — as generated by CubeMX). Build the CM7 Debug configuration as well as CM4 if dual-core booting needs to be preserved.

User application files:

• firmware/CM7/Core/Src/PI.c — encoder velocity measurement, filter, and PI controller with ramp and anti-windup
• firmware/CM7/Core/Src/motor_control.c — PWM + H-bridge direction control, stepper sleep/dir handling
• firmware/CM7/Core/Src/main.c — UART parser, 10 ms control loop, telemetry

After reset, the STM32 waits for the ready command (buzzer signal) before accepting velocity and stepper motor setpoints.

ROS 2

Requirements: ROS 2 Humble, python3-serial, inputs package.

cd ros2_ws
source /opt/ros/humble/setup.bash
colcon build --symlink-install
source install/setup.bash
ros2 launch robot_control robot.launch.py

The UART port can be overridden using the stm_bridge node parameter:

ros2 run robot_control stm_bridge --ros-args -p port:=/dev/ttyACM0 -p baudrate:=115200

Docker (Jetson)

cd ros2_ws
sudo docker build -t robot_control:humble .
xhost +local:root
sudo docker run -it --rm --network host \
  --runtime nvidia \
  -e DISPLAY=$DISPLAY \
  -v /tmp/.X11-unix:/tmp/.X11-unix \
  --device /dev/input/js0 \
  --device /dev/ttyACM0 \
  robot_control:humble

Inside the container: source /home/ros_user/ws/install/setup.bash && ros2 launch robot_control robot.launch.py.

MATLAB

control/pi_identification.m sends a sequence of lspeed/rspeed step inputs and plots the setpoint vs. measured response for all four wheels. Configure portName to your serial port (COM18 on Windows, /dev/ttyACM0 on Linux).

PCB

KiCad 8 project: pcb/PCBV2.kicad_pro. Production Gerbers are located in pcb/gerber/. Schematic preview: pcb/PCBV2.pdf.

UART Protocol

See docs/uart.md.