Research On Driving Technique Of 100% Low Floor Vehicle On Virtuai Orbit

Virtual orbit transit without solid track and waiting platform, have feature both of flexible control like city bus and large volume like subway and light rail, combining the advantages of them.100% low floor vehicles abolished the traditional wheel axle and debased floor height down to 350mm, make the convenience of on and off to passengers, especially the elderly, the disabled and children,100% low floor vehicles have many advantages in environmental protection, energy saving and improving traffic state. The thesis based on the research project of National Laboratory, virtual orbit transit vehicle driving technology, I mainly carry out the following work for 100% low floor vehicles driving technology on virtual orbit:Independent wheel drive control mode was confirmed. Driving study of 100% low floor vehicles is mainly concentrated on the steering frame at home and abroad, the flexibility of this control is not good. In this thesis, we determined the control mode of independent wheel drive, namely differential control driving scheme based on DSP+FPGA in wheel motors independently, the scheme can achieve 100% low floor vehicles drive control with modern signal processing technology, and the system has high precision.Simulation model was analyzed. Analyzed the principle and mathematical model of Brushless DC motor, the simulation model including Hall sensors of four brushless DC motors with driving system of differential control was established.Mode6 state counter module, inverter driving pulse generating module and current feedback module etc were designed in the model, which based on the hall sensor output pulses and avoid s function. The simulation results are consistent with the theoretical analysis.Differential control theory was studied, the steering model of independent wheel differential control generally use Ackermann model, but this model has a larger radius, this paper studied the steering model of front and rear wheels reverse rotation in differential speed, the radius of it can be reduced a half, having a higher flexibility. Besides, the paper studied the differential control algorithm of four wheel independently drive, it can calculate the expect speed during driven process.Independent control experiment of mutual feed motor was down. Hub motor independent wheel drive system or controller is design based on DSP or FPGA generally. The thesis designed control system by synthesizing advantages of DSP and FPGA, and designed the virtual orbit transit motor reciprocal power fed experimental platform. The experimental results of the mutual fed machine show that the control system based on DSP+FPGA can independently control two motors with high accuracy and small delay, and finally realize the loading operation of the control system.