Study On The Control System For Hydraulic Hybrid Vehicle

The study on the control system for hydraulic hybrid vehicle (HHV) based on hydrostatic transmission was presented in this dissertation. The research was performed in the process of building prototype vehicle of HHV.1. The control system scheme for HHV was studied and analysised. Firstly, Rear axle drive/brake scheme for HHV was picked out after scheme comparsion, in which, the hydraulic variable motor (HVM) connecting rear axle made HHV has the ability to integrate drive and braking. Meanwhile, engine, hydraulic variable pump and hydraulic accumulator composed Power Source of HHV. Secondly, the scheme of control system was studied. Based on the idea of integrate control and distribuated process, control system scheme was determined, which included Execution-Level, PS Electronic Control Unit (ECU) and Drive/Brake ECU, and Decision-Level, Master ECU. Moreover, they communciated each other by CAN bus. Thirdly, System analysis was carried out based on the control system for HHV, include analysising the plant and its parameters, idetitifiing the task of each ECU, and performing control strategy analysis, to obtain the initial control strategy.2. The drive/brake integrated control strategy was studied based on the fact that HVM could perform drive and braking by adjusting it displacement. By combining vehicle longitudinal dynamical and HVM control technology, the integrated strategy was estabilished: the skip/skid controller was to limite the torque produced by HVM, while speed controller was to meet driver's speed requirement. Finally, a more realistic braking control strategy was presented based on it.3. The energy management, using predictive information, was studied. By combining system pressure of hydrostatic transmission, vehicle load and predictive vehicle load, the energy management had the ability to achieve better fuel performance for HHV, in which, predictive information could obtain by using T-S fuzzy adaptive algorithm and Elman neural network.4. The design and Implementation of the control system. Based on the idea of combining core unit and peripheral circuit to implemente ECU hardware, while the software was accomplished by using C and assemble language.5. The design and Implementation of the monitor system based on the CAN-bus. By comparing three schemes, monitor system using CAN-bus was picked out, which had hardware and software. Computer and CAN-bus analysis instrument composed the hardware, while the software included DSP embedded software and monitor software based on the C ++ Builder.6. The prototype vehicle was built up, and some control system tests were arried out. Modern technology on the development of electronic control system, such as hardware-in-the-loop, was adopted to accelerate the development of control system for HHV.