Movements and Balance Control of a Wheel-Leg Robot Based on Uncertainty and Disturbance Estimation Method

In order to control the posture, balance and movements of a wheel-leg robot(WLR) precisely, some problems have to be solved. The major problems involve the strongly coupling of movement states, the composite uncertainty with modeling errors, the time-varying internal and the external disturbances. In this paper, a force controller based on the uncertainty and disturbance estimation(UDE) method is designed. The feedforward compensation based on dynamic model allows for compliant and more precise motion control. The UDE can estimate and compensate the composite uncertainty without any priori information effectively. The posture controller is designed based on the virtual model control. The whole controller which includes the posture controller and the movements balance controller is proposed and applied for WLR that built in Webots. The simulation results of trajectory control, balance control and robust test are presented to demonstrate the effectiveness of the whole controller.