Research Of Measure And Control System And Simulation Of Torsional Fatigue Testing Machine Based On Hydraulic Servo

Due to excellent performance, the large scale shaft parts, especially elasticcouplings, are widely used in many areas, including mining equipments, naval ships,petrochemical engineering, aerospace industry etc..It is necessary to develop a largetorsional torque testing machine to test the dynamic performance of the large scale shaftparts. Compared to a electrical servo system based on electric cylinder, a hydraulicservo system has excellent properties of higher output power, higher efficiency, lowercost. This thesis focuses on the scheme mechanic-electric-hydraulic system, electric-hydraulic system simulation, and design of the measurement and control system.In order to test the parts’ dynamic performance the linear motion is converted toshimmy motion through hydraulic cylinder and thrust ball bearing screw mechanism inthis torque testing machine, of the testing machine adapts Using FPGA (FieldProgrammable Gate Array) as core control unit to communicate with the host computerthrough USB and transfers sampling data and control commands, the measurement andcontrol system realizes algorithm in the FPGA to control the hydraulic parts and servomotor.Aiming at the simulation of mechanic-hydraulic system, a SolidWorks/Matlab co-simulation method is proposed. Firstly, the three dimensional entity is constructed inSolidWorks and converted to the corresponding SimMechanics model. Then, necessaryinterface modules and tested load model are added. The whole testing machine systemmodel is built through the hydraulic system SimMechanics model and PID controlleraccording to the system features. Finally, the position closed feedback and torque closedfeedback simulations is realized. The simulation results prove that the system has bettertracking performances which verify the system reliability.Aiming at the measure and control system features of the testing machine, firstly,through analysis and comparing the kinds of methods, taking the requirement costresource utilization and expand into account, select the host computer+servo controllerscheme. Take FPGA as the core control unit, combine the USB bus achieve thecommunication with the host computer, and control the hydraulic parts and servo motor.Then, analyse the FPGA base measurement and control scheme, emphasis on thehardware design of the FPGA core circuit, USB interface circuit, AD sample circuit,DA convert circuit, memory circuit, power circuit etc. Finally, design the software framework, divide into three parts: FPGA bottom control program, USB firmwareprogram and device driver and application program. Design the three parts programrespectively, and give the FPGA program design and simulation. The simulation resultdemonstrate that the FPGA design satisfy the chips time sequence.