Development Of Servo Valve Control Hydraulic Cylinder System For Double Nozzle Baffle And Development Of Test

The electric hydraulic servo systems feature some advantages such as high output power, high control precision, good control performance and robustness. Among these systems, because of the simple structure and small spatial volume, valve controlled asymmetric cylinder is widely applied in hydraulic servo system. The valve controlled asymmetric cylinder is composed of hydraulic components and signal processing equipment whose nonlinearity and dynamic performance greatly restrict the control effects of the system. Since the servo valve and hydraulic cylinder are the most important of the servo valve controlled asymmetric cylinder, research on accurate modeling and simulation of the system and its components is of great significant for improving the control performance of the system. In order to investigate the modeling and simulation of the servo valve controlled cylinder system effectively, it is necessary to optimize the mathematic model of the system and design a test rig which can display a high control performance. Therefore, a comprehensive model of servo valve was proposed in this thesis. Also, the comparison and analysis between the new model and other two models proposed in the past were described by evaluating the close degree to the built AMEsim model. Finally, the design about the mechanical, hydraulic, electrical systems of the test rig including were illustrated. The main contents of this thesis were described as follows:In chapter 1, an overview of the working principle for double nozzle flapper servo valve controlled unsymmetrical hydraulic cylinder position system was given, the research status and technology situation of double nozzle flapper servo valve at home and abroad were presented respectively, the existing problems in the electro-hydraulic position servo system, the trends of the test rig for this system and research contents in the thesis were pointed out.In chapter 2, a mathematic model by adopting the state space method was introduced according the requirements of modeling and linearization of the system. This model included four parts:motor toque, armature baffle components, slide valve in double nozzle flapper servo valve and asymmetric hydraulic cylinder. An accurate model of the servo valve controlled hydraulic cylinder system was derived and used for designing. In the end, a 3D model was built.In chapter 3, the comparison and numerical computation between three built models about the double nozzle flapper servo valve were made by adopting the built AMEsim model as a criterion. In addition, a necessary simulation and analysis about the synergic movement position system and amplitude swing system based on AMEsim were given, which was beneficial for the subsequent design in hydraulic servo system.In chapter 4, more design requirements and tasks were put forward according to the existed problems in both synergic movement position system and amplitude swing system, the mechanical part and hydraulic part in the system and the overall layout of 3D model of the system were designed, requirements about the control performance in the system are proposed in the thesis.In chapter 5, the analysis and discussion about the design the strong power and weak power system in the electrical part of the servo valve controlled asymmetric cylinder system was proposed based on high accuracy control function of the system. Meanwhile, a design of the hardware and software of the control system based on DSPACE was made. A controller by using DSPACE and Simulink was finally designed.In chapter 6, the conclusion about the major research contents of the thesis were made and some recommendation for future work was proposed.