Study On Electro Hydraulic Servo Friction Loading Technology

The electro-hydraulic servo friction loading technique can be used in the electro-hydraulic servo load simulation and collision simulation and so on, specific such as space capsule expansion simulation, load simulator, collision simulator and so on. Traditional load simulator is a drive device for bearing device of the load force applied to, is in the middle of the rigid connection, thereby the problem of surplus force, surplus force is not to completely eliminate the cause of traditional way of loading it is difficult to improve the bandwidth and precision of loading;traditional collision simulator is the acceleration waveform simulation, it is difficult to achieve a higher bandwidth of high precision wave form reappeared. The friction load and intermediate links with friction side instead of the rigid connection, so there is no problem of surplus force, the theory can be loaded with better performance.Electro hydraulic servo friction loading technology is a new technology, this technique not only have the advantages of extraneous force, but have the shortcomings of one-direction load and friction link control performance instability and so on. In this paper, simulation research on friction links, friction force loading system is linear and nonlinear mathematical model of modeling, which can expand the linear analysis of the key parameters of the system, and according to the synthetic hydraulic system flow servo valve and mechanical system supporting frame stiffness of comprehensive design. According to the linear loading method,the test bench is designed and built in the paper. To set up the test bench, we need to study the control characteristics of the system. The control characteristic of the clamping force system is directly determined by the control characteristic of the clamping force system. Therefore, the PID controller and feedback controller are used to simulate the clamping force system, and the basic control characteristics of the system are obtained.After analyzing and studying the basic control characteristics of the whole system, a good test bench is set up, and the experiment results are verified by experiment. First, the friction characteristics of the system are studied, and the friction characteristics of various friction materials are analyzed, and the friction materials are selected according to the experimental results. In view of the phase lag in the system, the feed forward controller is designed and verified.The fluctuation of the friction coefficient is reflected in the control of friction,and the common controller, such as the PID controller, can not adapt to thefluctuation of the friction coefficient. This is a kind of system uncertainty.According to the design of the robust controller, respectively with a robust controller and a robust H-infinity controller of the system of control analysis,finally has carried on the system identification of the actual system, according to the identified transfer function to design a robust controller and in test in certain extent improve the simulation waveform instability problems.Because of the little research of electro hydraulic servo friction loading technology at home and abroad, there are still a lot of work needs to be designed and studied.