Method to Improve the Control Performance of Ball Robot in Driving Control

Recently, with the development of batteries and location recognition technology, the field of application of mobile robots that can move is expanding. Most mobile robots use four wheels to implement a movement function, so they are strong in straight-line driving, but have limitations in direction change and rotation in a fixed place. On the other hand, the ball robot using a ball as a wheel has a structure with one point of contact with the ground, so it has the advantage of being free to change direction in a narrow space compared to the existing mobile robot based on four wheels. Due to its structurally unstable characteristics, posture control is required in addition to driving control. In this study, a control method was proposed to improve the control performance in the driving control of the ball robot. A PID controller for posture control and a PID controller for driving control for a ball robot, which is composed of a bowling ball, motor, omni wheel, acceleration sensor, battery, control board, and body, were designed. For posture control, information from angle and acceleration sensors was used, and for driving control, image processing information was used. Through the test of driving control performance, it was confirmed that the control performance of ball robot was improved by adding the body tilt angle in the moving direction and the reference moving distance to the existing PID control gain as the control input conditions.