Method for adaptively controlling neutral positions of steering wheels of electric power-assisted steering systems

Abstract

The invention discloses a method for adaptively controlling neutral positions of steering wheels of electric power-assisted steering systems. The method includes detecting current turning angles of each steering wheel, the rotational speeds of the steering wheel, torque of the steering wheel, vehicle speeds and wheel speeds of four wheels in real time when the corresponding vehicle run straightly; correcting offset of the neutral positions of each steering wheel if difference values of the turning angles of the steering wheel, the rotational speeds of the steering wheel, the torque of the steering wheel and the wheel speeds of the four wheels are respectively smaller than respective preset thresholds, the vehicle speeds are larger than preset thresholds and the current turning angles of the steering wheel are not zero in preset time ranges. The method has the advantages that the offset of the neutral points of the steering wheels due to mechanical abrasion of gears and racks of steering engines in usage procedures of the vehicle can be corrected, and accordingly the neutral positions of turning angles of the steering wheels can be assuredly matched with current real turning angles of vehicles; processes for calibrating the neutral positions of the steering wheels can be replaced, and accordingly users can learn the accurate neutral positions of the steering wheels without the processes for calibrating the neutral positions of the steering wheels of the integral vehicles after the integral vehicles are used for a period of time.

Description

technical field [0001] The invention relates to a control method of an electric power steering system, in particular to an adaptive control method for the neutral position of a steering wheel of the electric power steering system. Background technique [0002] In the electric power steering system that introduces the steering wheel angle to compensate or limit the power assist torque, the accuracy of the steering wheel angle is very important, and the steering wheel angle SA is relative to the neutral position (that is, the zero angle position SA_Zero_Offset). That is, SA=SA_Sensed-SA_Zero_Offset. [0003] The existing steering wheel angle calculation method is generally to calibrate the center position of the steering wheel when the whole vehicle is off the assembly line. If the middle position of the controller ECU reference remains unchanged, it will cause an error in the calculated steering wheel angle, affect the calculation of the assist torque, and affect the driving...

AI Technical Summary

Problems solved by technology

[0003] The existing steering wheel angle calculation method is generally to calibrate the center position of the steering wheel when the whole vehicle is off the assembly line. If the middle position of the controller ECU reference remains unchanged, it will cause errors in the calculated steering wheel angle, which will affect the calculation of the assist torque and affect the driving of the vehicle.

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