Motion synchronization for dual-cylinder electrohydraulic lift systems

This paper presents a nonlinear control algorithm to address the motion synchronization problem for a dual-cylinder electrohydraulic (EH) lift system. A two-step design approach is applied that utilized linear multiple input-multiple output (MIMO) robust control technique to design an outer-loop motion synchronization controller. A nonlinear single input-single output (SISO) perturbation observer-based pressure-force controller is designed for each of the lift cylinders as the inner-loop controller to handle the nonlinearities associated with the EH actuators. Experimental results on a 2-cylinder lift system verified the effectiveness of the proposed approach.