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

Abstract

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. INDEX TERMS Uncertainty and disturbance estimator (UDE), wheel-leg robot, virtual model control.

UDE-Based Robust Walking Control of a Bipedal Robot

“…In this case, it is enough to choose strictly proper stable first-order low pass filter G f (s) = [1/(Ts + 1)] with a time constant T [5]. Replace d with u d in (6), there is (8) Substituting ( 8) to (3), there is…”

“…The proposed method prevents the singularity problem of the controller, which might be influenced by the inverse operation. Design of robustness of movements balance controller in wheelleg robot [8], trajectory tracking control of underwater vehicle-manipulator systems [9], interaction control with an uncertain robot and its unknown environment [10], and bounded UDE-based control for a quadrotor [11] are some more examples to cite.…”

Modeling and Control of a Wheeled Biped Robot

“…Experiments showed that this method could achieve good trajectory tracking and interference suppression. Xin et al [ 12 ] established a motion balance controller for a WBR based on the inverse dynamics and uncertainty and disturbance estimation (UDE) method, and verified the robustness of the method by simulations. Wang et al [ 13 ] proposed an interconnection and damping assignment-passivity-based control (IDA-PBC) method, which can enable the WBR to obtain a wide range of stability.…”

A Robust Observer for Sensor Faults Estimation on n-DOF Manipulator in Constrained Framework Environment

“…As the highly coupled nonlinear characteristics, the actuator fault causes obvious effects on the system dynamics; therefore, they can be easily detected through monitoring abnormal system performances. Following the literature of actuator fault detection and isolation, and estimation, such fault can be considered as matched or mismatched disturbances and observed by using observers such as extended state observers (ESO) [15], [18], [19], disturbance observers (DO) [12], [20]- [22], uncertainty and disturbance estimator (UDE) [23], [24], time-delayed estimation (TDE) [25]- [27], super-twisting algorithm [28], Kalman estimators [29], unknown input observer [30], [31], etc. Then, Fault-tolerant control (FTC) that combines these observers compensation with advanced control algorithms such as active disturbance rejection control (ADRC) [32], [33], adaptive algorithms [34]- [36], or high robust gains can be employed to address the influence of the actuator fault.…”