Design And Control Research On Drive System Of Hydro Static Transmission Loader

The HST loader is a loader, its work system and the travel system use thehydraulic pressure actuation. Along with the technology progress and the demandscope expansion, the HST loader will be able to become popular. However, there aregreat differences in hydraulic components, controllers and control algorithms. Adoptingadvanced transmission device and scientific control strategies for improving loaderperformance has become core technology. Due to the poor performance ofhydrodynamic drive in accelerate, speed, transmission efficiency and layout, hydrostatictransmission is more popular in small and medium sized loader. The traditionalopen-loop control and single control of hydraulic pump or hydraulic motor can nolonger meet the requirements of the development of the hydro static transmissionloader. Based on coordination control of diesel engine, hydraulic pump, hydraulicmotor，this paper put forward three-variable control strategy.In the subject, based on small and medium-sized hydraulic loaders as study object,design the HST loader drive system. This article makes selection calculation onhydraulic pumps, hydraulic motors and diesel engines and other equipment. Thenestablish experimental platform. This paper establishes UIP diesel engine model andhydraulic pumps-hydraulic motor volumetric speed control model through AMESimand MATLAB/Simulink. Calibrate the model according to the test data. According tothe principle of the hydraulic system and loader work characteristics, proposed a threevariables control method. On the basis of the model, verify the three variables controlstrategy by simulation, and analysis of the diesel engine speed, fuel consumption,hydraulic pump displacement, hydraulic motor displacement, hydraulic motor speed,hydraulic system pressure and other parameters curve. Design the overall controlstrategy based on the actual situation of the loader, including starting condition,economic conditions, rated shovel condition and the maximum torque condition.Describe each condition program. Design and develop the control system of theexperimental platform, including program design, system monitoring, hardwarecircuit design and electrical circuit design. This control system can switch for manualcontrol and automatic control. Write PC interface with LabVIEW software. Its functionincludes modified online, storage of experimental data, the screenshot feature. Dodifferent experiments, including the stationary motor displacement experiments, thestationary pump displacement experiments, and three variables control experiments.Verify the three variables control strategy on the model. This paper carries on thecomparative analysis between simulation results under the three variables control andsimulation results under traditional control. For fuel consumption economy of thethree-variable control and traditional control, carries on the comparative experimentand analysis.The results show that the test platform runs well. It can simulate a singlepump-single motor drive system and dual-pump-dual motor drive system. The modelthat established in AMESim and MATLAB/Simulink is correct, can conduct thesimulation to the power system. The three variables control strategy is better thantraditional control strategy. In the case of the same motor speed and load, the fuel economy of three variables control changes with different set system pressure value.If the set pressure value is reasonable, the economic property and pressure stability ofHST loader are improved significantly. It is beneficial to the life and efficiency of thehydraulic components that the pressure is stable and controllable.