| At present, the braking system of car is still mainly a "hydraulic braking system", even if ABS, TCS and other systems are fitted on the car, the status that hydraulic braking system playing dominant role has not changed. Although the car fitted with ABS can prevent wheels from locking and shorten the braking distance effectively, but the sign of heat fade caused by frequent braking or continous downhill road braking is not improved. Besides the frictional brake system, an electromagnetic brake system is added on the car, to improve the car braking performance by controlling the two systems cooperatively is possible technical approach. Therefore, significance of research on integrated system of electromagnetic brake and frictional brake is very important. While some similar studies have been developped in China and abroad, but most research mainly aimed at the passenger-cars's retarder or truck's retarder, and a few research on the electromagnetic brake for cars is not considered in joint control of the two braking systems, most of the research mainly aimed at the miniature model, no related report mentions about the integrated system of electromagnetic brake and frictional brake. Aiming at these problems, the study in this thesis is focused on the following aspects:First, the structure arrangement of the integrated system of electromagnetic brake and frictional brake was presented; layout method of the intergrated system with certain type car was described in detail. According to the structure arrangement, one-wheel braking model of the integrated system after simplification was given.The optimization design method was used. Improved brake torque as possible as goal, the article analyzed the influence law between the main composition parameters of the integrated system and brake torque. Meanwhile, applied the intergrated system composition parameters analysis method, different model selection schemes which was different in composition parameters was proposed on comparative analysis. According to the software Mathematica and Maltab which were applied to calculate, simulate and analyze, the optimum composition parameters were obtained.Acquisition of the magnetic induction is very important to control the electromagnetic brake and calculate its torque, and the current calculation formula to the magnetic induction was too complex to apply in engineering. According to potential theory and Maxwell equations, the prediction model of magnetic induction on some point of the brake disc generated by the electromagnetic brake was built. Aimed at certain structure for the electromagnetic brake, magnetic induction on some point of the brake disc was analyzed and calculated. Magnetic induction prediction was carried on under different width and length of magnetic pole and different distance between magnetic pole and brake disc, we developed magnetic field analysis by the software Ansoft Maxwell 2D/3D.According to the composition parameters sheme, the article presented the regulation method that the intergrated system total torque varies as the current to the electromagnetic coil changed, which was based on the principle of PWM regulation. The simulation software Proteus was applied, combined with the system control model and control strategy, the vehicle braking performance was simulated. The result shows that PWM regulation method presented is feasible.On the basis of fuzzy control theory and the theory of optimal control, the intergrated system of electromagnetic brake and the frictional brake control model was constructed. Based on fuzzy control theory, the control strategy that controlling the current of the electromagnetic brake coil through fuzzy controlled method was proposed, in which the vehicle slip rate was used as input, the current of the electromagnetic brake was used as output. According to the control strategy, fuzzy controller was designed. To prove its validity and feasibility, the vehicle equipped with the integrated system including vehicle electromagnetic brake and frictional brake was taken as example. The simulation analysis to the integrated system was preceded by using software MATLAB/Simulink. Based on the theory of optimal control, the software Matlab/Simulink was applied to design the intergrated system, optimal feedback K and the braking torque of the frictional brake, from which the total braking torque was obtained.According to the principle of the intergrated system of electromagnetic brake and frictional brake, combined with the vehicle performance characteristics, the testing bench of the intergrated system was designed, the acquisition system software was designed based on the software Lab VIEW. The expeiments focused on relationship among blend brake torque, electromagnetic brake torque and frictional brake torque and the influence of different parameters to the blend brake torque was carried on.Finally, in order to make the intergrated system favorable to attach and apply in different type vehicle, five performance index to the intergrated system was presented, evaluation method to the performance index was given at the same time, the intergrate system type selection was evaluated on the basis of extension assessment method and the rough set theory.The innovations of this paper are:(1) The structure scheme to the intergrated system of electromagnetic brake and frictional brake was presented. According to the structural optimization design, the optimum structure parameters and installation parameters of the intergrated system were presented.(2) According to potential theory and Maxwell equations, the prediction model of magnetic induction on some point of the brake disc generated by the electromagnetic brake was built.(3) The regulation method that the intergrated system total torque varies as the current to the electromagnetic coil changed was presented, which was based on the principle of PWM regulation. Based on fuzzy control theory, the control strategy that controlling the current of the electromagnetic brake coil by fuzzy controlled method was proposed, the vehicle control model was designed. Based on the theory of optimal control, finish-time infinite quadratic form optimal control model was constructed. Applying the testing bench, some comtrast test and resistance of heat performance test were carried on, which the integrated system can regulating the gross braking torque under the designed control strategy and having good resistance of heat performance was verified.(4) The intergrate system type selection was evaluated on the basis of extension assessment method and the rough set theory.
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