Characteristics Analysis And Control Research On Power-Driven System Of Full Hydraulic Bulldozer

Today, with the rapid development of construction machinery industry, the performance of the Construction Vehicles has been significantly improved and enhanced, such as Bulldozer.But there are also many questions still need better solution, such as the vehicle's power performance, economy and operational efficiency and other issues, but the key factor of the problem is the vehicle travel driving system's performance quality.Hydraulic drive system has been wide applied in construction machinery industry for its unique features and advantages. Currently, advanced bulldozers and other construction vehicles were almost all powered by all-hydrostatic driving system. The quality of the overall performance of a system is related to each element's own performance, how components matching with each other and control strategies. Traditional hydrostatic drive system often control single variable and ignore the matching between the elements, this method cause the system cannot play its best performance. In order to effectively solve this problem, this paper come up with three-variable control strategy witch means joint control engine speed, pump and motor displacement the three variables. This method takes the matching between the elements into consideration,and makes each element's efficiency be completely play.This paper analyzes the pump's and the motor's efficiency and lifetime affecting factors,and get the system parameters' optimal ranges after overall consideration. Based on improving the system's power and economy performance,I contrapose the Bulldozer's working characteristics come up with a best matching method between components. Taking the test-bed as the prototype, I use Simscape component library under Simulink software establish hydraulic system simulation model, then combine with diesel machine model and PID control model constitutes a whole hydraulic drive system model. Take the pump displacement, the motor displacement and the load torque as characteristic parameters, and take seven levels throughout their ranges. Take the system pressure and motor speed as the observation target, use the experimental design method to do correlation analysis and get the dependency relationships between parameters and each target observations. Fit system pressure's and motor speed's prediction model obtained for each condition in the engine system, and evaluate and verify the models. worked out the contour map between system pressure with pump and motor displacement and the motor speed with pump and motor displacement, analysed the influence relation. According to the matching method, the forecast model and the correlation between parameters, proposed the concrete three-variable control strategy for each condition, and then doing the simulation analysis and experimental verification. At last, we draw a conclusion that the control strategy can make the system progress in stability, and the power, economy, operational efficiency also be increased.