Dynamic Improvement of Hydraulic Excavator Using Pressure Feedback and Gain Scheduled Model Predictive Control

This work focuses on a gain scheduled Model Predictive Controller (MPC) for the dynamic performance enhancement of an excavator boom. The method can be generalized and applied to similar machines with the installation of pressure and boom angle transducers without modifying the hydraulic circuit of the system. In the proposed method, the transient part of pressure signals is isolated and used to counteract the actuator vibrations through a valve-based compensator. A full-scale model of an excavator's arm has been used for the experimental verification of the proposed approach. The experiments are conducted under various conditions with the proposed controller and compared with the conventional system. Since the stability of these types of machines is extremely important from the safety point of view, a stability analysis has been carried out and closed-loop stability of the system is ensured with the proposed controller. A significant reduction of 58% and 41% have been achieved in the cost function under maximum velocity extension and lowering phase respectively, where maximum boom oscillations are observed. Furthermore, an average vibration reduction of 46 % is obtained using the proposed method.