Study On The Reverse-driving Control Method Of Hydrostatic Tandem-Drum Vibratory Roller

Hydrostatic tandem-drum vibratory rollers generally use the reverse-driving braking during the decelerating or stopping process. By adjusting the displacement of variable pump of driving system to zero, the natural braking ability of closed circuits hydraulic system is utilized to make the machine stopping. This braking mode will cause the engine to exceed the speed limit, bring high peak pressure to hydraulic system and influence the compaction quality seriously. Therefore, it is of great theoretical significance and application value to study on reverse-driving process for hydrostatic vehicles。Based on the analyses and research on the reverse-driving braking principle of hydrostatic tandem-drum vibratory roller, combining the test data of braking test, the reasons that cause the engine speed exceeding its limit and, the relief valve open during the reverse-driving braking process of hydraulic vehicles are found of. Dynamic equation of driving system is established, The idea that controlling reverse-driving process in order to reduce the harm is proposed, The control method of ideal stopping curve is given. By using this method, the braking ability of closed circuits hydraulic system can be made use of to realize stopping fast and smoothly, without the engine speed rising excessively, and high pressure peak occurring. The simulation model is established to research the reverse-driving process with application of the control method posed in this thesis based on the AMESim software. Given the pump curve designed, the hydraulic pressure shock and the engine speed is simulated. The simulation results show that the control method is feasible and efficient.