Motion Controller Study On Electro-Hydraulic Position Control System

An electro-hydraulic servo system has the advantages of fast response speed,high stability of transmission,large power output of the system and strong resisitance of load capacity,so it is one of the best choice in motion control fields for heavy load,high frequency response and high precision.With the Electro-hydraulic servo system is applied in space-vehicle systems,robotic systems and the heavy mechanical industry,this phenomenon set athis phenomenon higher demand on the Electro-hydraulic servo system.According to the Electro-hydraulic servo system,PLC and other general motion controllers are usually used as a controller with the system at present.The control algorithm in the controller needs to spend a lot of human and material resources to develop.The control speed and the precision determine the price of the controller.Although there have been foreign products of motion controllers for electro-hydraulic servo systems,most of them are according to the hydraulic valves of our company which cannot be used in common.The control algorithm in the controller often adopts PID control which cannot realize optimal control of the system under complicated working conditions.Because motion controllers for the electro-hydraulic servo system start relatively late in China,the monopoly position of foreign products causes the virtual-high controller price.Aiming at these problems,so it is much important to study motion controllers for electro-hydraulic servo systems.This paper chooses the typical position system in the electro-hydraulic servo system and conducts the following researches and designs:Aspects of algorithms which motion controllers for electro-hydraulic position servo systems integrate with.Because of the uncertainty of the parameters for Electro-hydraulic position servo system model,the parameters of the system are identified by the LM algorithm based on the theoretical model.The mathematical model is obtained with higher fitting to the true controlled object so that it provides a theoretical basis to tune the parameters of controllers.In order to realize that optimized control parameters of the controller can be tuned by different controlled objects,this paper adopts the compound control algorithm with the combination of the fuzzy model reference control algorithm and the feedforward algorithm.The fuzzy model reference control algorithm as the part of the closed-loop control algorithm has advantages of both fuzzy control and self-adaptive control and has a better control performance by self-tuning of control parameters.The feasibilities of the LM algorithm and the compound control algorithm in the electro-hydraulic position servo system are validated respectively by the co-simulation of AMESim and Simulink.Because there are differences between system model and real model,The LM algorithm and the compound control algorithm are verified in Matlab/Simulink by using the prototype development of the cotroller based on xPC.The results show the rationality of the LM algorithm for identifing the electro-hydraulic position servo system and that the compound control algorithm improves the control performance for the system.Aspects of the software and hardware design which are for electro-hydraulic position servo systems.This paper adopts the STM32F103ZET6 microprocessor of ST company as the core chip of the controller.In order to guarantee the coordination of all real-time tasks for the controller,the priorities to each part of the software program are divided rationally with operating uC/OS-II system transplantation to STM32F103ZET6.The peripheral circuit of the controller is the “carrier” of the connection between the controller and the Electro-hydraulic position servo system.The software and hardware designs of the controller realize the communication with a host computer,the sending of the control signal and the receiving of the feedback signal.Acoording to the simulation of the hardware circuit,the property of designed hardware interface circuits is verified which provides the theoretical basis for the design of the hardware circuit of the controller.Meanwhile the given control signal of the controller and the real time monitoring of the control state are realized by designing a good man-machine interface.