Research And Design Of Control System For Electro-hydraulic Universal Testing Machine

With the development of materials science and the improvement of material experiment standards,new requirements are also put forward for material testing machine.The electro-hydraulic servo universal testing machine is one of the most widely used material testing machines at present.And it is of great significance to transform and upgrade its control system.This subject is mainly aimed at upgrading and reforming of the WAW-1000 B electro-hydraulic servo universal testing machine of Hongshan Testing Machine Co.,Ltd.Firstly,the overall structure of the electro-hydraulic servo universal testing machine is introduced,its detection devices and hydraulic loading system are analyzed,and the mathematical model of electro-hydraulic servo valve and hydraulic cylinder is constructed.Secondly,the functional requirements of the electro-hydraulic servo universal testing machine system is proposed based on the analysis rasults.Thirdly,the hardware design and software design of the controller prototype were carried out based on the design plan.Finally,the function test and material tensile test of the controller prototype are carried out.The functions of the system include data acquisition function,servo control function,and network communication function.The data collection function mainly completes the collection of signal of pressure sensor,displacement sensor,and deformation sensor,and provides feedback for servo control system.The servo control function is mainly to adjust the electro-hydraulic servo valve based on the sensor data to control the loading,and to ensure the smooth switching of the control mode.The network communication adopts Modbus TCP communication method,which realizes stable,reliable,efficient and real-time data transmission.The system parameters of the controller are mapped to the Modbus holding registers.The upper computer can call or set the internal parameters of the controller by reading and writing the corresponding Modbus holding registers,so as to realize the monitoring and control of the experiment process.The controller software is designed based on the RT-Thread real-time operating system,and is divided into modules such as data acquisition program,servo control program,and network communication program according to system functions.Each functional module is scheduled by the real-time operating system according to thread interruption and thread priority.The control system of the electro-hydraulic servo universal testing machine designed in this paper has completed the basic function test,and the displacement control and pressure control accuracy are less than 1%,which meets the control accuracy requirements of the universal testing machine,which can prove that the system design scheme is feasible.The control technology of the electro-hydraulic servo universal testing machine is one of the core technologies of the electro-hydraulic servo universal testing machine.The development of a control system with independent intellectual property rights can improve product competitiveness and reduce costs.