Study On The Control Strategy Of Electric Differential Of MACCP With Motorized Wheels

The two In-wheels Drive Electric Vehicle (EV) is one of the developing directions for future EVs. Its development has been synchronizing with that of the researching and industrializing of EVs in the word. Because of its perfect controlling performance and potential in engineering applications, more and more efforts have been devoted to the two In-wheels Drive EV by both academicians and engineers alike. The technology of designing and manufacturing in-wheel-motor developed rapidly, and there are many companies specializing on the in-wheel-motor .But it is unsolved for the total vehicle control technology of EV with motorized wheels. The dissertation made an in-depth research on the theory and application of motorized wheels driving for electric vehicle.Firstly, the dynamics simulation mode of MACCP is established in Adams. It includes front double-links independent suspension and rear double-links independent suspension, the rack and pinion steering gear's pinion and rack, the Fiala model of tire. Base on the model, the simulation desktop of the electric vehicle with motorized wheels is established using Matlab/Simulink and Adams. The desktop can simulate many kinds driving mode of vehicle. It is the foundation for the research in this paper.Secondly, the article author build a small motor dynamometer which is used to open up and design control logic and algorithm of system during period, which gets some important motor parameter algorithm in the test for true the Mini Advance Chassis Control Platform. The platform includes a motor, a photoelectrical encoder, a torque sensor, a magnetic powder brake, frame of motor dynamometer and the hardware circuit of testing system. The measure system is made up of the photoelectrical encoder and the torque sensor, which measure respectively motor speed and torque. After getting the motor speed and torque, the measure system transmits the signal to control motor system.The magnetic powder offers the labor which motor needs. The frame of motor dynamometer links the motor, the photoelectrical encoder, the torque sensor and the magnetic powder brake. The hardware circuit of testing system controls the motor and the magnetic power. On the basis of the small motor dynamometer, we measure permanent magnetic direct current motor's mechanical features parameter. It offers parameter to motor controller. Because we must know motor's lag in response time constant. At the same time the small motor dynamometer is the foundation for the research for the later lab's work.Thirdly, the principle of the electric differential of traditional vehicle and correlative research is introduced and the deficiency is discussed. Consequently, the self-regulation method to realized the electric differential by controlling the torque of the motor and freeing it's speed is brought out. Using the foregoing simulation desktop, all kinds of driving mode of vehicle running with different wheel speed is simulated. It is proved that the control method is reasonable and feasible by simulation result, all wheels doesn't skid on all driving mode and the rotation speed matches the wheel center speed by self-adjusting. For knowing whether MACCP can run along the straight line, whetherMACCP can turn around ideal path, we must find a control viable to scout the MACCP's status. After comparing some kind of scheme, we regard yaw rate as feedback variable. Because (1) When MACCP runs alone straight line, the ideal value of yaw rate is 0. (2) When MACCP runs around , the ideal yaw rate isδ?u/L. In this way we can closed-loop control MACCP through controlling yaw rate.In the paper we regard yaw rate as feedback variable. The conclusion is correct through MACCP running along straight line and turning around ideal path. There are errors between left driving torque and right driving torque, because left motor and right motor are different and motor controller is not accurate. There are errors in process of machining ,manufacture and fit. They will effect MACCP's manipulating stability and driving stability at the variousroad condition. When MACCP runs along straight line without steering control force, there is a sinusoidal driving moment disturbance on the right driving torque and there is error in MACCP's kinetic model camber angle. And the camber error is 1o .In such a situation we verify whether MACCP run along straight line. It is proved that through controlling yaw rate we can make MACCP run along the straight line and turn around ideal path.In the vehicle turn course, there is definite friction between each spare of steering system. This kind of friction is reputed the steering system's dry friction and always reverses with nodal direction of motion. It includes steering system's dry friction and steering gear's dry friction. Steering system dry friction is in favor of MACCP's stability. Without moment of force disturbance, it can reduce MACCP's eave. When there is the difference between left driving torque and right driving torque, it can cut down the driving torque disturbance. And it can keep MACCP runing along straight line. The dry friction and steering wheel's aligning torque are main parts of steering wheel helm control moment of force. On the basis of the simulation desktop of the electric vehicle with motorized wheels, all kinds of driving mode of MACCP running is simulated. It is proved that steering system dry friction could increase MACCP's stability.