Enhancing Disturbance-Rejection Performance of Wheeled Inverted Pendulum Systems with Knee-Wheel Integrated Control

Mobile wheeled inverted pendulum (MWIP) vehicles are prone to lose maneuverability and attitude stability when encountering steep slopes or crossing ground obstacles due to their inherent unstable and underdriven dynamics. Therefore, the problem of anti-disturbance control has been a major issue in the control design of MWIP systems. In this study, we calculate the theoretical stabilization range of a first-order wheeled inverted pendulum to ensure the safe operation of the MWIP. Additionally, the knee joint degree of freedom is added on the basis of the first-order inverted pendulum to build a wheel-leg MWIP system. We introduced knee joint rotation when the robot is near the edge of losing control, which improves balance and enables obstacle crossing in complex environments. Simulations of balance control with a 4 cm and 5 cm radius semi-cylinder verified the effectiveness of the method.