Study Of Characteristics Of Hydrostatic Driving Secondary Regulation System

Hydrostatic driving secondary regulation technology is a kind of hydrostatic driving technique, which developed from the last seventies of 20th century in Germany . The control of secondary regulation system is different from the regulation of traditional primary element, is the system that directly adjusting secondary element which transform hydraulic energy to mechanical energy mutually. It adapts to changes of the external load by adjusting the inclination of the slant plate of a secondary component. Because of offering energy recover and reuse, hydrostatic driving secondary regulation technology can improve the working efficiency of the whole hydrostatic system. It undoubtedly has expansive application foreground in nowadays. In this thesis, taking a secondary regulation toque-loading equipment table as the concrete object, the secondary regulation system is studied in deep and width.After consulting numerous data home and aboard, the development and application status of the secondary regulation is narrated in detail, the apply examples in every apply field is illustrated, the features of secondary regulation technology is summarized. On this basic, the research direction of the thesis is determined.The composition and the principle of operation of the secondary regulation system is introduced in the thesis. The radical controlling rules of the secondary regulation system concluding: rotational velocity control, torque control and constant power control.The static velocity modifying specialties of a secondary regulated system under alternative load is studied in theory. Under a constant torque load, a secondary component has to adjust its slant plate over zero point to realize the working conversion from motor to pump. The secondary component has three working states, such as, driving state, driving-reverse state and energy-consuming braking state. It may work in all the four quadrants, but it has no stable working point while working as a pump.The mathematical model of the secondary regulated torque loading equipment is finished, after establishing the models of pressure-constant displacement pump, hydraulic accumulator and secondary component. Dynamic performances and the PID control of the speed control subsystem in torque loading equipment with secondary regulation are engaged. The analysis result demonstrate that the speed system is stable when the PID control is not given, but the response speed is very slow, however, the response speed is enhanced and the control performances is improved when the PID control is given. Analyse the speed stiffness of the speed control system, the results indicate that the LF speed stiffness is very low in the condition of open loop, but LF speed stiffness is enhanced in the condition of double closed loop.