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A tire force estimation algorithm is proposed for vehicle dynamic stability control (DSC) system to protect the vehicle from deviation of the normal dynamics attitude and to realize the improved dynamics stability in limited driving conditions. The developed algorithm is based on the theoretical analysis of all the subsystems of the active brake control in DSC system and modulation in DSC, and the robustness is achieved by a compensation method using nonlinear filter in the real time control. The software-in-loop simulation using Matlab/AMEsim and the ground test in the real car show the validation of this method.

This paper simulates the working process of Automated Mechanical Transmission (AMT), especially establishes an efficient method of engine output torque estimation based on tests and a dynamic model of engage process of clutch. Then, a continuous/discrete hybrid system model of AMT control system is established based on Matlab/Simulink/Stateflow. The transitions between different states are described in details and the control flow chart is offered. Compared with the vehicle test results, the simulation model is reliable. The simulation model will well help to develop AMT control system and improve its performance.

Anti-lock Braking System (ABS) is an important control system that can improve the automotive performance, reliability and safety obviously. Hardware-in-the-loop Simulation (HILS) testing is a promising method to assistant design automotive electronics system. In the State Key Laboratory of Automotive Safety and Energy, a HILS system was established to assistant design ABS. The HILS system is composed of a hydraulic control unit of ABS, a normal brake system, a commercial personal computer, a data acquisition card, and several signal-conditioning modules. Powerful software was programmed to perform managing input and output signals, solving 7-freedom and 15-freedom vehicle models, and acquiring response signals of the brake system. Based on the simulations of HILS system, the road experiments with the same conditions of ABS are very necessary and important.

Electro-hydraulic power steering system (EHPS) uses the motor as the power source instead of the engine to assist drivers to steer. Compared with traditional hydraulic power steering system (HPS), EHPS system has a better performance in energy saving and driving feeling. In EHPS system, the speed control of the motor determines the performance of the whole system. In this paper, a speed control system of brushless direct current (BLDC) motor based on a Fuzzy-PI controller is established. In addition to the function to adjust speed by adjusting voltage, field weakening is utilized to get a wider speed range, so that the EHPS system has a better performance.

The performance of Hydraulic Anti-lock Braking System (ABS) is important to vehicle brake safety. In this paper, finite element models and simulation models for studying dynamic response of solenoid valve, a critical part of ABS, are established. Based on the calculation results, which are proved in experiment, several effective methods for improving the performance of the solenoid valve are presented. Furthermore, an ABS-vehicle model is developed to study the influence of hydraulic ABS parameters on braking effect. The simulation results have good agreement with the data of in-vehicle driving experiments.

The four-wheel-independent Electro-hydraulic Braking system (4WI EHB) is a wet type Brake-by-Wire system for passenger vehicle and is suitable for electric vehicle (EV) and hybrid electric vehicle (HEV) to cooperate with regenerative braking. This paper gives a review on the design concepts of the 4WI EHB from the following three aspects. 1. Hydraulic architectures. 2. Design concepts of the brake actuator. 3. Installation of the components on the vehicle. Simulations and experiments are carried out to further explore the performance of hydraulic backup and implicit hardware redundancy (IHR). A method to integrate the IHR with hydraulic backup without increasing the total amount of valves is proposed, making the IHR cost and weight competitive. By reviewing various design concepts and analyzing their advantages and drawbacks, a cost and weight competitive design concept of the 4WI EHB with good fail-safe and fault-tolerant performance is proposed.

High speed on-off valve is applied widely in vehicle control systems. When high speed on-off valve is controlled by Pulse Width Modulation (PWM) of high frequency, the valve core can float at a certain position which is adjusted by changing the duty ratio within a certain effective range. Then the high speed on-off valve can control the flow and pressure linearly like proportional valve. Thus it is essential to extend the effective range of duty ratio to improve the linear control performance of high speed on-off valve. In this paper, the high speed on-off valve of the automotive Electronic Stability Program (ESP) is the focus, and its flow force is analyzed in detail to get the effects of hydraulic parameters on the valve performance. The mathematic model of the high speed on-off valve is derived. Then the valve structural parameters are optimized according to the Genetic Algorithm(GA), offering the theoretical references for extending the effective duty ratio of PWM.