Wireless Controlled Two Wheel Balancing Robot

The idea of two wheel self balancing robot had gain popularity among control system researchers worldwide over the last decade. This thesis aimed to design and build a two wheel self balancing robot that can be controlled remotely. The electronic circuit design for the robot was split into parts and connected together through ribbon cable. The robot chassis was constructed using acrylic and mounted on two motors with 440RPM. Battery weighing 80g was placed on top of the chassis.IMU, which comprises of a triple-axis accelerometer and a dual-axis gyroscope, was chosen as robot tilt angle sensor. Analog voltage readings from IMU were converted to tilt angle values and passed through Kalman filter for data fusion. A PID controller wasincorporated to each motor for motor closed loop speed control with motor back-EMF readings as motor speed feedback and PWM duty cycle as controller output. A main PID controller was implemented as the control system for robot balancing with Kalman filtered tilt angle readings as feedback and motor PID controller speed set point value as controller output. A pair of 315MHz RF module was used for robot remote controlling. Data transmitted were encoded to minimize probability of interference by similar source. Microcontroller was linked to the computer through UART for data analyzing on the computer as well as real-time tuning of Kalman filter as well as PID controller through the computer. Lastly, the aim for this project was fully achieved. The robot was able to balance by itself on two wheels with little drift on smooth surface while powered up. The robot can be controlled by the RF controller to move in four directions with random delay caused by noise, which was expected due to low cost RF module used.