| Because there have huge advantages in environmental protection and energy saving, the research and application of electric vehicle became an important direction of vehicle research field, the research level of active safety and energy recovery in this field also increasing day by day. Common electric vehicle often inherits the traditional internal combustion engine vehicle's hydraulic brake system, the braking mode ignores the factor that the motor regenerative braking can effectively recycling braking energy, so many vehicles use the composite brake system that motor regenerative braking combined with traditional hydraulic braking. ABS of EV composite brake system is often inherited from the hydraulic ABS of traditional vehicles, but some electric motor's advantages will be wasted by using hydraulic ABS individually, such as easy to control, regulate the torque quickly and accurately. A vehicle with four electric wheels was studied, and brake integrated control strategy based on composite braking force distribution and pure electric motor ABS control was proposed, also a composite ABS control theory based on motor ABS works together with hydraulic ABS was proposed.Braking stability, braking efficiency and energy recovery of vehicle in different braking modes were considered, and the relationship between regeneration braking force, hydraulic braking force and pure motor ABS was rational regulated in the program of brake integrated control strategy. Four ABS control methods were proposed. They are logic threshold control based on threshold library, variable logic threshold control based on road determine by the increase of wheel acceleration in equal times, variable parameters'PID control based on road determine by the logic threshold method, the parallel control of PID primary control with logic threshold method auxiliary control. The feature that best slip-rate are different according to road condition was considered in the methods above. Through comprehensive determining vehicle speed, target braking strength and real-time road conditions, to changing the characteristics that control thresholds or control parameters were fixed, and to selecting different threshold values or control parameters by different conditions. So the wheel slip-rate was near the ideal value, and the brake stability was improved. The latter three methods used logic threshold method to determine the road at the beginning, according to analysis the increase of the wheel acceleration to estimate the road, so that the road identification was more accurate. The co-simulation model of electric wheel vehicle based on AMESim and Simulink was built, the control strategy was simulated. Through design and renovation, a hardware in the loop real-time platform based on two dSPACE simulate platform was built, and the variable parameters'PID control based on road determine by the logic threshold method hardware in the loop test was carried out. Composite ABS control theory of electric wheel vehicle based on motor ABS coordinate work with hydraulic ABS was also proposed, and simulation analysis was carried out. By judging brake conditions, ABS control mode been switched. Based on simulation and hardware in the loop studies, it can be proved that the control strategy can effectively identify the braking conditions, and take timely reasonable control, the control effect is better, so the article lays the foundation for the study of electric wheel vehicle active safety integrated control. Specific research contents of this paper are as follows.1. According to the driving characteristics and dynamic performance of four-wheel independent drive electric vehicles, parameters of motor are designed and the electric motor is chosen. On the analysis of the domestic and international electric vehicle composite braking theory and ABS control method, put forward on the basis of electric wheels vehicle brake integrated control scheme. The scheme combined with ideal braking force distribution curve, according to the target braking strength switching braking mode, the stability and recycling braking energy are both considerated. When in low intensity braking, give full consideration to the braking energy recovery, motor regenerative braking force is used alone, and it can fully satisfy braking requirements. When in medium intensity braking, the braking mode is chosen that the motor regenerative braking is given priority, and the hydraulic friction braking as the auxiliary. And when in high intensity braking, by estimating the current road friction coefficient, we calculates the maximum braking force of wheel don't locked in the current road conditions, through analyzing and adjusting the braking force as hydraulic braking force, and the insufficient part used regenerative braking force to supply. The braking mode has fully considered the energy recovery in the low brake strength, brake efficiency in medium braking strength, and the braking stability in the high strength, to switching braking mode. According to the above four-wheel independent drive electric vehicle's composite braking force distribution mode, pure electric motor ABS control method that through control the electric motor braking torque to achieve antilock functions is proposed. In the low strength braking and the medium strength braking, the change range of the motor brake torque can fully satisfy that the total braking torque won't continue to make the wheel locked. And when the target braking strength is large, when vehicle in lock state, a single wheel required braking force is bigger. And because the motor brake torque is limited, it is hard to use distribution methods that the motor braking as primarily, hydraulic braking as the auxiliary to separately adjust motor torque to realize ABS function. Therefore the unlocked hydraulic braking force is adopt as the main control mode, and the electric motor braking force as auxiliary, by regulating electric motor braking torque to realize ABS function.2. According to the composite brake system for electric car wheel and pure motor ABS control mode, put forward four kinds of ABS control methods. They are logic threshold control based on threshold library, variable logic threshold control based on road determine by the increase of wheel acceleration in equal times, variable parameters' PID control based on road determine by the logic threshold method, the parallel control of PID primary control with logic threshold method auxiliary control. Among them, logic threshold control method based on threshold library put the road friction coefficient estimate in the road friction coeffient module as the threshold setting reference condition, according to estimates current road surface, speed and other conditions for logic threshold settings, to achieve real-time ABS control. Three control methods after initial use logic threshold method to judge road conditions, according to the analysis judgment road conditions of the acceleration of growth when round the size, road coefficient estimates more accurate identification. For parallel control methods PID control is in use by default, and PID control failure module has been in judging PID control effect. Once the PID control is failure, the system switches to logic threshold method, this method can avoid the problems such as instability and the ability of anti-interference is poor when used PID control method alone.3. Based on AMESim and Simulink established 15 dof vehicle dynamics simulation model, and in view of the above four different ABS control methods on the simulation analysis.4. Composite ABS control theory is put forward based on logical threshold method all-wheel drive electric wheels car. This theory is different from the pure ABS braking integrated control method, but with hydraulic motor ABS control coordination ABS control theory. Through the analysis of different braking conditions for ABS control mode switch, and simulation analysis, analyzed the parameters on the control performance influence.5. For pure motor ABS control mode based on logical threshold method under judgment of the variable parameters of road, PID control method in our traditional automobile brake antilock brake on the basis of test platform designed and renovated, based on double the hardware in the loop test-bed dSPACE. The hardware in the loop simulation platform used a computer as host, two dSPACE simulation platform as the target machine of real-time simulation platform. One of those dSPACE simulation platform of vehicle dynamics model for real-time simulation, the other dSPACE simulation platform for brake integrated control simulation. Through the hardware in the loop simulation experiment and off-line simulation test this study control algorithm can effectively identify brake operating conditions, and can be reasonable control, the control effect is good, as research electric wheels car active safety integrated control laid a foundation.
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