Yaw And Sideslip Control For Light Vehicle With Electromechanical Brake System

As a branch of x-by-wire, Electromechanical Brake (EMB) introduces a fire-new conception to Brake System. EMB transmit brake requests with electronic single, and provide clamp force with a set of actuator driven by electronic motor. Therefore, EMB is more rapid and safer than traditional brake system. As a new brake system that will be used in the future, EMB wipes off hydraulic system and complex pipelines. Thus, the layout of automotive is predigested, the weight is reduced and the pollution caused by brake fluid is eliminated.In this paper, drawing on domestic and international theoretical results and practical experience based on EMB, making use of the resources achieved by our research group, we finish the estimation of clamp force, design and debugging of tri-loop controller for EMB motor, Improvement of the. All of these researches are based on the characteristics of our self-developed; An EMB hardware in the loop test-bed is developed based on Matlab / xPC technology; Yaw and sideslip control algorithm is developed and simulated both with the EMB simulation software and the test-bed. The control algorithm is debugged and the effectiveness of the algorithm is verified.1 Estimation of Clamp Force of EMB ActuatorThe theoretical basis is determined for estimation of clamp force of EMB actuator. A clamp force estimation test-bed based on CANOE was developed. We acquire the relationship between clamp force and ball-screw displacement or motor current according to the test. A mathematical model which is used to improve EMB model and provide solutions for clamp force feedback control algorithm based on sensor fusion is obtained2 Research on Yaw and Sideslip Control Algorithm Based on EMBMaking analysis of stability control results making use of yaw angular velocity, sideslip angle, yaw angular velocity combined with sideslip angle as target variables for control system separately, then chooses the yaw angular velocity and sideslip angle as target variables for control system. Yaw moment controller is designed, of which uses PID controller for yaw angular velocity and PI controller for sideslip angle. In order to adjust the proportion of compensatory yaw moment produced by two variables, the coefficientαis introduced. On choosing of target wheels, we make lateral rear wheel as auxiliary target wheel, according to comparing and analysis results with auxiliary target wheel and without auxiliary target wheel, the method is testified to be effective on improving control effect.3 Design of EMB Motor ControllerOn control of the EMB motor, a tri-loop control plan is confirmed. The inner loop is current control loop, the second loop is speed control loop while the clamping force control loop is the outer loop, PI controllers are used in them. Through off-line simulation and hardware testing, the controller parameters are determined, through the step input, sinusoidal input off-line simulation and hardware tests prove that the designed motor controller model and hardware controllers can meet the requirements to achieve accurate control of clamping force.4 Secondary Development of EMB Simulation Software and Simulation and Study of Yaw and Sideslip control algorithmAccording to the math Mathematical model acquired by estimation of clamp force of EMB actuator, the EMB simulation software is secondary developed.Yaw and sideslip control algorithm model is established under Matlab/Simulink environment. Based on EMB simulation software, yaw and sideslip control off-line simulation tests are carried out under conditions of 0.7Hz sinusoidal wave turning with increasing amplitude, alterable adhesion road, square wave steering and double change lane. The simulation results show that: EMB simulation software is qualified to develop and test yaw and sideslip control algorithm; the yaw rate variety can be effectively controlled by the designed control algorithm, the sideslip angle is restricted, lateral stability of the vehicle is effectively improved.5 Establishment of EMB Hardware In-the-Loop Test-bed and Test of Yaw and Sideslip control algorithm with Test-bedAccording to the scheme of EMB hardware in the loop test platform, EMB HIL test platform is built on the basis of Matlab/xPC Target, and then HIL tests of yaw and sideslip control algorithm are executed based on the platform. The test results show that: the EMB HIL test platform satisfy the design requirement; under-turning and over-turning of the vehicle can be efficiently restricted by the control algorithm, and lateral stability of the vehicle is obviously improved.