Abstract:Coordinated control algorithm for variable pump controlling variable motor (VPCVM) is presented to overcome the defects, such as huge overflow losses, slow speed regulating and poor full capacity utilization, of variable pump and variable motor controlled independently. The variable pump closedloop control was to realize motor expected speed initiatively,while the variable motor was controlled by predictive control according to the pump displacement and motor expected speed, resulting in adjusting displacements of pump and motor concurrently.The variable pump closed-loop control was time-variant system and controlled by single neuron adaptive proportion integration differential (PID) control algorithm. The variable motor predictive displacement was calculated according to the pump displacement and motor expected speed for its control. The actual motor control displacement was obtained from the motor predictive displacement amended by fuzzy control algorithm whose two inputs were according to motor speed error and the change rate of motor speed error. Comparative simulation and experiment show that the coordinated control algorithm has the capacity for speeding up system response and reducing overflow losses for VPCVM system, and verified its correctness and effectiveness.