Research On The Control System And Dynamic And Static Characteristics Of High Precision Testing Machine

The torsion testing machine is used to test the flexible shaft parts such as coupling,especially dynamics characters and the strength of flexible coupling. The machine ismainly used to twist, stretch and compress the test piece. The testing machine controlledby hydroelectric servo valve has some problems with control precision while testinghuge flexible shaft as well as oil spills and so on. This paper researches on testingmachine controlled by electric cylinder which controls the servo motor to command thetesting machine, then completing the experiment. The followings are the main researchcontents and relevant conclusion.①According to the demand of testing machine, and basing on the theory of ballscrew to design preliminarily the structures of testing machine. The parameters and thetransmission are finished as well as the selection of electric cylinder. After establishingmechanical system dynamics model, we analysis the dynamics characters of eachcomposition. Comparing to hydroelectric servo system, there are higher precision andbetter results in the electric testing machine system.②Due to the data calculated above, we build the3D model of torsion testingmachine with software SOLIDWORKS. Through the process of virtual assemblysimulation, the mutual interference cases of mechanical parts in testing machine areanalyzed. The result shows no interference problems.③In connection with the control system, we derive the mathematical model of thecontrol system. Then in order to get the response curve, we use soft wareMATLAB/SIMULINK to emulate the control system. The result shows that the servoamplifier has an apparent influence, while the influence of the stiffness of load torque issmall. However, when it is at the high frequency, the moment of inertia makes theamplitude attenuation. The servo amplifier affects the step response more apparentlythan the others, and the rigidity of load influence the amplitude, meanwhile, the effectof moment of inertia is smaller. There are available measurements to solve theseproblems in chapter3.④It is common that the traditional PID controller has some problems such as theslow response and obvious procrastination. In order to solve them, the controlparameters must be optimized to get better response. Because genetic algorithm is verystrong ability to optimize without control the parameters directly, we design a new controller which is used to optimize these parameters based on genetic algorithm in thisthesis. Then we simulate genetic algorithm with software MATLAB, after programmingthe MATLAB language, we get the optimal solutions. It indicates that the parametersoptimized by genetic algorithm have better adaptive capacity than traditional PIDcontroller and the anti-jamming capability improves obviously.⑤To study the performance and control system of testing machine, the simulationsoftware for measurement and control system of testing machine is designed byadopting virtual instrument Lab VIEW to acquire and deal with the data from the foursensors. Simultaneously we design a relatively good interactive interface to inputcontrol parameters to command the testing machine. More important, it can display thefour time curves to monitor the testing machine better, like displacement-time, force-time, angle-time, and torque-time.