An Adaptive Robust Impedance Control Considering Energy-Saving of Hydraulic Excavator Boom and Stick Systems

In this article, taking the hydraulic system of mining hydraulic excavator boom and stick as the plant, an adaptive robust impedance controller based on an extended state observer and backstepping method is designed. The energy-saving operation and position tracking performance are considered in system modeling and control law design. The system effects on electro-hydraulic proportional valves with open centers and flow regeneration valves (FRVs) are considered. When hydraulic cylinders are extended, the proposed control strategy adopts a pump-controlled pressure closed-loop to shorten the dead time. When hydraulic cylinders are retracted, less oil is output to meet the idle demand. The valve-controlled position subsystem with impedance mode ensures smoother digging processes. Comparative simulations show that the proposed control strategy has better position tracking and smaller velocity fluctuations. Compared with the system without FRVs, the proposed system can reduce energy consumption by 27.32%.