Research On Design And Control Strategy Of The Hydraulic Hybrid Excavator Slewing

With the growing worsening of environment pollution and energy shortage, nowadays more and more engineering machinery manufactures focus on researches of hybrid technology to redue fuel consumption. Based on the secondary regulation technology which is a kind of new hydrostatic transmission technology, the main work is to research the design and control strategy of the hydraulic hybrid excavator slewing.First of all, based on the analysis of the characteristics of common large-size excavators slewing system, an appropriate hydraulic hybrid excavator slewing is designed which is driven by two hydraulic pump/motor. And a simulation model is established to accomplish the matching analysis and to test main parameters in the model.Secondly, the corresponding mathematical model is established and simplified accoding to the designed system. Then, on the one hand, a double closed-loop PID control algorithm is designed for a single set of the speed control system based on the simple mathematical model, and the influence of the main parameters on the system is analyzed. On the other hand, the corresponding double sets are built and the cause of synchronous error is analyzed. All what have been done above are the preparations for the design of control algorithm of the single set and synchronous control of the double sets.Thirdly, in light of the change of the intertia of the slewing in a large range and the existence of unknown disturbances, a robust H￥ controller is designed for the single-set speed control system. The simulation results show that, compared with the PID controller, the robust H￥ controller has greater stability and robustness, satisfying the desired performance requirements of the single set.Finally, in order to analyze the impact of main parameters on the slewing system and to preliminarily research the brake energy recovery and recycle, the corresponding experimental research is conducted by using hydraulic hybrid system test bench for rotate speed control, braking enery recovery.