Papers by Keyword: Electric Power Steering (EPS)

Abstract: In this paper, we propose a hardware-in-the-loop simulation (HILS) for functional safety compliant electric power steering (EPS) system. The proliferation of electric and electronic systems in vehicles has brought the new automotive standard ISO 26262 for the safety of functions. The proposed EPS system should be Automotive Safety Integrity Level (ASIL) D compliant, which is the highest ASIL level. Therefore, EPS system complies with functional safety and HILS is configured to verify performance of functional safety compliant EPS system.

Abstract: Aiming at the request of EPS system for the robust stability and the dynamic characteristic, the dynamics model of an electric power steering system (EPS) is established , the outer ring mixed H₂/H_∞ control based on genetic algorithm decides the values of the target torque and solves the perturbation problem, the inner ring control with PID control algorithm will never compromise with current real-time control. Simulation results show that the application of mixed H₂/H_∞ in the outer ring for current decision can make the EPS system stable and realize the ideal control performance, can also obtain the low frequency information from the surface of the road and depress the high frequency interference.With the application of current tracking loop PID control, EPS system has good dynamic characteristics of the target current real-time tracking, so that electric power steering system has better stability and traking performence.

Abstract: Electric power steering (EPS) systems are rapidly replacing existing traditional hydraulic power steering systems due to their important advantages such as fuel and cost savings, environmental compatibility and flexibility. Many articles are available in this field in which EPS is viewed only from one specific aspect. Other aspects have been introduced only by brief equations neglecting some main details regarding the important effects of ignored parts. Therefore, it is quite necessary to make a complete analysis of every part of this system with a right combination between them. It makes a comprehensive simulation system for EPS. This matter needs sufficient knowledge in mechanical, electrical and control sciences and how to assemble them with each other properly. Therefore, Mechatronic is the most appropriate branch of science to achieve this goal. In this paper, a complete model of EPS is presented which includes a 7-D.O.F mechanical model of steering system. A Permanent Magnet Synchronous Machine (PMSM) is used to supply the assist torque to steering column. Vector Control Method is utilized for controlling the motor. A PID controller determines the reference assist torque value. The results are presented to estimate the model precision and evaluation of model.

Abstract: The first of all, the multidisciplinary modeling and analyzing for the electric power steering system (EPS) is made. The design method based on the model is proposed and the EPS control system is analyzed. On the basis of deeply observing and studying S/T singular value curves, a robust control algorithm of back-calculation is put forward. After analyzing the deficiency in the single-loop control structure of the EPS, the dual-loop control structure of the EPS is developed. The inner loop controller is designed using the single neuron PID algorithm, and the new robust control algorithm is proposed to design the outer loop controller. The simulation results in the frequency-domain S/T curves of the EPS system and the hand force step input of the steering wheel show that the designed controller is simple and effective, and has good robust stability and robust performance.

Abstract: In order to ensure the safe and reliable operation of electric power steering(eps) system,the fault-tolerant control theory is used to design the feedback control for eps system and the control rule for sensor failure in the linear continuous system is described.On the basis of riccati equation,the design method and steps of fault-tolerant controller are given from the view of optimal control.By taking electric power steering of a certain mini car as research object,the simulation calculation is carried out.By applying such fault-tolerant controller for the eps system,the simulation results show that the system has no sensitiveness to the sensor faults,and the method can satisfy the demand of fault-tolerant control.

Abstract: This paper deals with the design comparison of interior permanent magnet (IPM) motors with fractional-slot winding configurations for an electric power steering (EPS) application. By making comparisons of these configurations based on cogging torque, torque ripple, average torque, and efficiency, an IPM rotor configuration has been chosen for use as a prototype motor. The Taguchi parameter method coupled with the finite element analysis (FEA) is employed to achieve the desired performance requirements within a reasonable geometry. To assess the rated current and thermal behavior of the motor, the lumped circuit models are conducted.

Abstract: The control strategy is one of the key technologies of EPS system, and the assistance characteristic has great importance to the vehicle handiness and road feeling. Based on the EPS dynamic model, the curved assistance characteristic is designed. The curved assistance characteristic has the superiority to find the better balance between handiness and road feeling. It has engineering significance to the overall design, function enhancement and optimization and steering manipulation and safety improvement.

Abstract: Under the special situation of lateral wind disturbance, the lateral direction was resulted from the conventional obverse control strategy and influenced the vehicle stability. The 2-DOF full-vehicle model with the lateral wind disturbance and EPS dynamic model were designed. Reverse control strategy was designed where the EPS motor provided active steering control to prevent vehicle deflection with the input signal of steering torque under the lateral wind disturbance. In the EPS working process, the reverse control strategy and obverse control strategy were switched according to the drive situation to obtain the best vehicle stability. Anti-disturbance simulation was executed and the results shown that the yaw rate, the slideslip angle, the lateral acceleration and the lateral displacement have been weakened, and the vehicle stability is enhanced. The design of reverse control strategy has engineering significance to the overall design, function enhancement and optimization and steering manipulation and safety improvement.

Abstract: Automotive EPS controller is easy to be affected by the parameter perturbations, road agitations, sensor noises and the lateral wind disturbance in the process of vehicle operation. These uncertainties affect the accuracy of assist current, the EPS performance and the driving safety. The mathematical model of EPS system was established including the internal uncertainty and external disturbance. The LFT linear fractional transform representing model and M matrix with stripped uncertainty were designed. The robust H∞ controller and weight function were designed according to the H∞ control theory and performance indexes of EPS system. The comparative performance with PD controller was made. The results showed that the H∞ controller had better robustness and robust stability than the PD controller. It also had great anti-disturbance performance to satisfy the performance requirements of EPS system.

Abstract: Aerobic granules were cultivated successively in column sequencing batch reactor (SBR) with the glucose as carbon source. The effect of copper (II) on the characteristics of aerobic granules was studied. Results showed that the physical, morphology and extracellular polymeric substances (EPS) of aerobic granules were influenced in different degree under different concentrations of copper (II) in sequencing batch reactor (SBR). The appropriate Cu2+ can be adsorbed by the microorganisms in aerobic granules under the functions of chelation and displacement of heavy metals. Under the Cu2+ concentration of 0.5～3.0mg/L, the stable MLSS and better settleable granules with higher S.G. and lower SVI can been attained in the reactors. The sludge can maintain the granules in stable till the Cu2+ concentration increases to 20.0mg/L. The ratios of EPSC/EPN distribute in 6.60～7.01 steadily under the Cu2+ concentration of 0.5～10.0mg/L.However, excess Cu2+ can destroy the metabolism balance of the microorganisms and the protein synthesization and genetic information transportation are baffled. When the Cu2+ concentration increase to 50mg/L, more filamentous appears in the granules and the compact granules change to in disperse. The ratios of EPSC/EPN evidently rise to 7.59 and 7.46 respectively under high Cu2+ concentration of 20.0mg/L and 50.0mg/L. It suggests that the microorganisms try to excreting more EPS and protecting itself from the environmental change.