On Sliding Mode Variable Structure Control-Based Electro-Hydraulic Servo System And Its Experiment

In accordance with control characteristics and performance demand of the electro-hydraulic servo system, a new control strategy of sliding mode variable structure control is applied in the general electro-hydraulic servo system, then a lot of simulation and experiment is done.There are some nonlinear factors, great indeterminacy and load disturbance in the real electro-hydraulic servo system inevitably. At the same time, we expect the steady-state error of the system is small, and the adjusting time is short. Therefore, it is very difficult for the designer to design the system. To overcome these disadvantages, and meet the demand of the system, the variable structure control with sliding mode approach is presented in this paper. The main characteristic of the sliding mode variable structure control is that: when the state of the system goes through the different areas of the state space, the structure of the feedback controller changes as some law. Thus, the system is robust to the inner parameter variation and outer environment interference and the system has better dynamic performanceIn the paper, having analyzed and studied the electro-hydraulic servo system in theory, its mathematical model is set up, and the involved parameters are calculated and determined. Further, a great number of simulation experiments verified the algorithm is effective. At last, by means of experiments, a real-time control program by LabVIEW is realized to control material testing machine. The results are proved to be satisfactory. And the influence of the supplying pressure and the control parameters with the system's dynamic characteristics is studied. Therefore, not only on the theory and simulation but also in the real system experiments, by using the sliding mode control, the system have the characteristics such as the fast speed quality, smooth control, better dynamic performance following with that being carried out easily for microcomputer; which lay a foundation to apply them in practices and production.