| Secondary regulation of hydrostatic transmission technology is a new type of hydraulic drive technology. It is based on the net of constant pressure, accommodating the variety of the load by changing the camplate's obliquity of the secondary unit (axial piston pump /motor),and so the flow changed, to adapt to the changes in load torque. By utilizing the four-quadrant characteristic of the secondary unit, the braking system of kinetic energy and potential energy heavy can be reused, so the technique has high efficiency and good effect of energy saving. Hydrostatic Transmission of secondary regulation is actually a generic term for a class of systems. Such systems can be divided into the speed control system, the position control system, the torque control systems and the power control systems by its scope of application. The speed feedback in the above systems are essential, as a result, It can be divided into displacement-spring-force feedback programme and electronic feedback programme. The so-called displacement-spring-force feedback programme is that using a speed measurement motor to detect speed and feedback the results to displacement - spring - force feedback proportional control valve, so the hydraulic motor displacement control is achieved. The so-called electronic feedback programmes is that using a speed measurement motor or a photoelectric codec instrument to measure the speed and achieve speed feedback.Because of the sharpening machine trolley hydraulic system in view of the valve is not to stop in the work process starts, the brake as well as the reciprocal motion, created the massive energy loss, the paper proposed that used secondary regulation technology in the sharpening machine trolley hydraulic system. First of all the paper research on the composition and working principle of the secondary regulation hydrostatic drive system,used the SIMLINK software to establish the displacement-spring-strength feedback proportion variable displacement pump's digital simulation model, and has carried on the dynamic simulation analysis to the pump model. Secondly, take billet sharpening machine trolley as system's load object to establish the mathematical models of secondary regulation hydrostatic transmission. In the foundation of establishing each part mathematical model, obtained the mathematical models of secondary regulation hydrostatic transmission, and takes the system simulation model. Finally, carryed on the energy conservation characteristic analysis of secondary regulation hydrostatic transmission system and conducts the thorough research to the system each operating mode parameter to the system returns-ratio influence. The result had indicated that system's energy recovery efficiency related on the system's pressure, system's rotational speed and load actuation torque and along with each parameter's enlargement, system's recovery efficiency increases. Used the conventional PID control method to carry on the speed control experiment of the system, the simulation result shows that the electricity feedback is better compared to the displacement-spring-strength feedback speed control effect,but, the displacement-spring-strength feedback speed system is lower and the performance-to-price ratio is higher compared to the electricity system. |
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