4-DOF Adaptive Fuzzy Sliding Mode Control of Excavator

Abstract

To realize the trajectory tracking control of the excavator rotation and working device,the 4-DOF kinematics and Lagrangian dynamics equation of the excavator rotation and working device is established. The excavator's working device has obvious nonlinear,uncertainty characteristics and external disturbance,so the sliding mode variable structure theory is introduced into the control system. In view of the fact that the chattering of the sliding mode control may activate high frequency dynamic and damage controller components,an adaptive fuzzy sliding mode control is designed. The control law consists of three parts:Equivalent control,adjustment control and switching control. The switching gain is adjusted by using the adaptive fuzzy system outputs to approach the upper bound of the system uncertainty,so the switching control becomes continuous,the chattering is alleviated and the control system has strong adaptive tracking capability. Aiming at a whole dig-unloading process,the developed controller is employed in simulation test,the tracking performance of adaptive fuzzy sliding mode control and the effect of control input are presented.