Model Predictive Control Method For Unidirectional Speed-variable Proportional Pump-controlled Asymmetric Cylinder

Nowadays,more and more attention is paid to the energy-saving performance of industrial equipment.Unidirectional proportional pump-controlled asymmetric cylinder system is quite popular in the design of high-precision forming hydraulic press due to its high-saving ability.However,it is very difficult to carry out its systematic analysis theoretically because its high non-linear characteristics.This paper does some research on the position control of unidirectional speed-variable proportional pump-controlled asymmetric cylinder based on the high-precision forming hydraulic press.Analyzing the operating principle and characteristics of the system,a three-order state space model with constraints is proposed based on the flow continuity equation and the force balance equation.What's more,this paper also proposes a design of model predictive controller applicable to the model to guarantee and satisfy the control demands of the system based on parameter identification and such three-order model.It effectively transfers the demands of position control,non-overshooting and pump's unidirectional rotation into a quadratic optimization problem with inequality constraints.The feasibility and effectiveness of the controller is validated through simulation.At last,a comparison between PID controller and model predictive controller is carried out based on the xPC Target experiment platform.And control performance of model predictive controller aiming at various objective values is studied.Experiment results indicate that model predictive control algorithm can be successfully applied to unidirectional speed-variable proportional pump-controlled asymmetric cylinder position control system.The model predictive controller is superior to the traditional PID controller,with the merits of debugging simply,high control precision and strong generalizability.