| As the good economic performance and low emissions, hybrid electric vehicles become more and more popular. Regenerative braking improves vehicle economic performance and has become a research topic. As an active safety technology, vehicle stability control system can inhibit the over turning of vehicles and severe understeering tendency, to improve vehicle handling and stability. The hybrid vehicles equipped with the vehicle stability system has become a trendence. This requires a hybrid vehicle have regenerative braking and stability control functions. It needs the study the integrated control algorithm of regenerative braking and stability control for hybrid electric vehicles.There are few paper of the research on integrated control of regenerative braking and stability for hybrid vehicles in the domestic and the abroad. This paper combined with 863 projects, international scientific, technological cooperation projects, provincial scientific and technological support projects etc. At the same time, it makes close cooperation with China FAW Group Corporation Technical Center. Hybrid electric vehicles are studied in the paper, and how to integrate the braking regenerative and the stability control algorithm become a main topic.This paper mainly includes three aspects, the distribution of regenerative braking force, vehicle stability control and the coordinated control algorithm of regenerative braking and vehicle stability control.(1) Base on the analysis of factors related to the distribution of regenerative braking forces of the hybrid vehicles, the author proposed the optimal control algorithm of electric motor braking force distribution. First, it analyzes the factors related to braking energy recovery rate in the hybrid vehicle. These factors mainly include: the vehicle braking strength in the cycle conditions, the characteristics of the electrical power generation, the battery charging characteristics and the engine drag torque hysteresis. It analysis power generating characteristics of the motor and charging characteristics of battery, according to motor maximum braking torque concerned the motor and battery. Considering the motor and the battery efficiency on the braking energy recovery, an improved adaptive genetic algorithm is proposed to calculate the maximum effective motor braking power, corresponding to the motor braking torque. According to the vehicle braking strength and optimal algorithm for electric power distribution system, it makes different braking force to the front and rear axles of vehicles, realizing the distribution of motor and hydraulic braking forces.(2) The paper studies the overall structure of control algorithm for vehicle braking stability. It estimates the state of the vehicle, identifies the stable state of the wheel and vehicle and study the yaw moment control algorithm. By estimating the state of the vehicle, dynamics integral and weight calculation module, the author proposes the hybrid observer to insure the estimation accuracy in the tire working range. To identify the stability of the wheel, the author uses the wheel acceleration, wheel slip rate and the threshold correction to determine additional wheel steady state. The method of phase plane was used as steady identifying state in the vehicle. The author analysis the impact of yaw rate and sideslip angle in the stability of vehicle. On this basis, the author also designs trigger and cut-off conditions for stable control algorithm in vehicle. In the yaw moment control algorithm, a gray PID control was used to calculate the target yaw moment in the research. The algorithm can effectively reduce the uncertainty of the control algorithm, using optimal tire force distribution algorithm to determine the yaw moment in the study. To ensure vehicle stability in the premise, the vehicle should make use of tire adhesion as far as possible.(3) The overall structure of coordination control algorithm of regenerative braking and stability was carried out in the research. The author develops the controller to coordinate the braking forces. The controller includes the coordination control of hydraulic and electrical power system, the coordination control of regenerative braking and wheel anti-lock braking (ABS), and the coordination control of regenerative braking and electronic stability control (ESP). Considering the driver's braking intention, the brake pedal travel was used to analysis electric power and hydraulic braking system for secondary distribution. The method can effectively guarantee the driver's braking force to meet the intent of the dynamic braking and regenerative braking to reduce the risk of triggering ABS. For the problems of frequent switching on hybrid vehicles among regenerative braking, ABS and ESP systems, the author designs the coordination algorithm of ABS, ESP and regenerative braking with the method of state machine. Considering the dynamic response characteristics between electric power system and the hydraulic braking force system, the author uses braking force to compensate electric hydraulic power system, according to the electric mechanism acting on the wheel driving force with the hydraulic braking force dynamic characteristics. At the same time, based on adaptive self-sliding mode control algorithm, the author designs the method to compensate hydraulic braking force. With the vehicle's dynamic and steady state, driver's braking force can meet the needs of the system power requirements and improve the smoothness of the braking process.(4) Based on Matlab/Simulink platform, an offline simulation platform for integrated regenerative braking and stability control algorithm is established in hybrid vehicles. The model simulation platform includes three parts, hybrid vehicles model, the controller model and the graphical user interface. Using different driving cycles, the author verifies the effectiveness of regeneration braking force distribution algorithm. On different steering test conditions, the author verifies the effectiveness of vehicle stability control algorithm. To verify the effectiveness of hydraulic braking force compensation control algorithm, the author uses the brake strength in the low and middle intensity. On cornering and straight line conditions, the author verifies the effectiveness of the coordinate control algorithm of stability control with regenerative braking control. The results have shown that the developed regenerative brake force distribution algorithm can effectively improve vehicle fuel economy for the recovery of braking energy. The vehicle stability algorithm can ensure the vehicle handling and stability in a variety of conditions, and the hydraulic braking force compensation control algorithm can ensure the vehicle's braking force needs to improve the braking process as well as to improve vehicle ride performance in the entire braking process. The coordinated control algorithm of regenerative braking and stability designed in the paper can not only guarantee braking stability, but also recover the braking energy as far as possible.(5) Based on the off-line simulation platform, a hybrid vehicle integrated regenerative braking and stability control hardware is established by using Matlab /xPC platform in the loop test bench. The test bench includes xPC Target real-time platform, sensors, data acquisition and processing systems, hardware bench and simulation software. And the hardware bench includes three parts, hydraulic braking system test bench, motor test bench, and operate board. The hardware in the loop test bench is used for verifying the effectiveness of the integrated control algorithm of regenerative braking and stability control in a variety of test conditions, the test results show that the developed control algorithm can effectively recover braking energy in a variety of conditions, and at same time, the algorithm can meet the needs of the driver's braking force as well as ensure that the vehicle handling and stability.
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