Electric power steering system with individually adjustable-parameter and curve-type power characteristic

Abstract

The invention provides an electric power steering system with an individually adjustable-parameter and curve-type power characteristic. The system is characterized in that: the power characteristic curve is a segmentation curve which is symmetric about the centre of a zero input moment point; an integral curve can be determined by setting 5 key parameter values on the curve, and, when one or more key parameters are regulated, the integrity of the curve and the continuity of the first-order derivative can still be guaranteed without modifying other parameters. The power characteristic of the electric power steering system provided by the invention can change the shape of the curve by adjusting 5 of the key parameter values to achieve different assisting effects, so the electric power steering system has the optimum steering performance which is expected by drivers.

Description

technical field [0001] The invention belongs to the technical field of automobiles, and relates to an electric power steering system, in particular to an electric power steering system (Electric PowerSteering System, EPS for short) with independently adjustable curve power characteristics. Background technique [0002] Electric power steering system is composed of traditional mechanical steering system (mainly including steering wheel, steering shaft, steering gear, steering rod mechanism, steering wheel) with torque sensor, electronic control unit, power steering motor and its reduction mechanism. Among them, the torque sensor is installed on the steering shaft to detect the driver's manipulation torque; the power assist motor can be installed on the steering shaft or the steering gear, and provides power assist torque to the driver through the reduction mechanism; the torque sensor signal and the vehicle speed sensor signal are input to the electronic control unit The basi...

AI Technical Summary

Problems solved by technology

[0003] Most of the traditional electric power steering control systems adopt linear or broken-line power boost characteristics, but the power boost gain of the linear power boost characteristic is a constant value when the vehicle speed is constant, and the high and low areas of the input steering torque cannot be distinguished and corresponding, so it is impossible to take into account Steering operation requires road feel in the middle position and steering portability; although the design of the broken-line power-assist feature compensates for this defect to a certain extent, the sudden change in the gradient at the turning point still damages the steering feeling, which is likely to cause a jumping feeling in the control force ; Although a few literatures mention the design method of curve-type power-assisted characteristics, there are still shortcomings such as unclear physical meaning of the selected constraint parameters, too simple or too complicated curve equation, and cumbersome calibration process.

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