Electro-hydraulic Servo Swashplate Piston Hydraulic Transformer

With the development of human society, the energy issue is becoming a hottopic. Researchers are focusing on how to improve the efficiency and reduce theenergy consumption in the field of hydraulic transmission. The secondary regulationtechnology can make the power source work around the high efficiency part,moreover, it could not only reduce the hydraulic system throttling losses but alsoreuse the negative energy load. Therefore, the secondary regulation technology cangreatly improve the transmission efficiency of the entire hydraulic system and have abroad application prospect. However, since the secondary regulation technology canonly be used for driving the rotating load, a new type hydraulic component(Hydraulic Transformer) is needed to control the linear load. The integrated hydraulictransformer combines the two functions of hydraulic pumps and motors functions inan element. The element has characteristics of compact structure and small volume. Itcan simplify the structure and improve the efficiency of the hydraulic system.Therefore, the research on the integrated hydraulic transformer is meaningful.Based on reading a large number of domestic and foreign literatures, the authormakes a classification of the current domestic and international research abouthydraulic transformers. And the author analyzes the works of the integrated hydraulictransformer and its application prospect, and expounds the application anddevelopment of domestic and international integrated hydraulic transformers. Besides,the key technology of the integrated hydraulic transformer is outlined and the mainresearch content is confirmed.The integrated hydraulic transformer is a new type of hydraulic components.Firstly, its transformer principle is analyzed in theory. Based on the theoreticalanalysis, the author designs the electro-hydraulic servo swing hydraulic motor as theservo drive mechanism. An electro-hydraulic servo swing hydraulic motorcontrolling the swash plate piston hydraulic transformer is designed. Overallinstitutions of electro-hydraulic servo swing hydraulic motor and hydraulictransformer are designed. The transformer ratio of the hydraulic transformer iscontrolled by the electro-hydraulic servo hydraulic motor. The advantages of thisdesign are small volume, compact structure, big transformer ration range, and fastdynamic response. Furthermore, the throttling loss is avoided theoretically.The optimal design about the hydraulic transformer plane is accomplished basedon the remaining compaction force and the remaining clamping torque. The geneticalgorithm is adopted for solving the optimal result. Because the flow transition process may not only occur in the upper or lower dead point, the phenomenon willlead to a flow pulsation. Therefore the buffer tank port plate of the hydraulictransformer is optimized. According to the characteristics of different buffer tankstructure, the eventual adoption of the triangle cones is used. as the structure of thevalve plate buffer tank The author constructs the model of the pressure buffer andmakes the simulation through MATLAB. As a result, the best structural parameters ofthe buffer tank are obtained. The flow distribution structure finite element offluid-structure interaction is analyzed by the ADINA. And the author makes the testof the noise lever of the hydraulic transformer.The traffic and torque characteristic analysis of the Electro-hydraulictransformer is the basis for the application of hydraulic transformers. Themathematical model, including the Electro-hydraulic transformer transient flowcharacteristics and the instantaneous torque characteristics, are deduced. The controlangle changes from zero to all areas. Simulation results show that the flow pulsation,torque ripple rate are large during the entire range. The author comparatively studiesthe multiple plungers of hydraulic transformer flow pulsation rate.Taking into account the nonlinear characteristic of the Electro-hydraulictransformer pressure control, the author studies its control strategy. A mathematicalmodel of the Electro-hydraulic transformer is constructed. The fuzzy-PID dual-modecontrol strategy for pressure control is designed. When the small deviations appear,the stability of the system can be improved by using the PID strategy and the error isreduced; when the large deviations appear, the system is made fast and intelligent byusing the fuzzy control. Based on the experience of theoretical analysis and manualtest, the author designs the fuzzy controller and builds a simulation model to studywith the software of MATLAB/Simulink.Finally, an Electro-hydraulic transformer which is the type of the swash plateaxial piston is designed, and the experimental platform is built. The control softwareis written by C++builder. On the experimental system of the hydraulic transformer,the author conducts experimental research. On the experimental platform, the authortests the performance of the hydraulic transformer and verifies the correctness andvalidity of the theoretical analysis and control strategy.