Electric power-assisted steering system and steering wheel angle median self-learning method thereof

Abstract

The invention discloses an electric power-assisted steering system with a steering wheel angle median self-learning function, and further provides a steering wheel angle median self-learning method ofthe electric power-assisted steering system. Steering wheel angle median self-learning is conducted through the following modes that when steering torque of a steering wheel is in a first preset steering torque range and the working condition that a vehicle speed is larger than a first vehicle speed threshold value lasts for first preset duration, a calibration request is sent out; if the steering wheel angle median calibration state is a non-calibration state and the working conditions that the difference value of the wheel speed sum of two of diagonal wheels and the wheel speed sum of the other two diagonal wheels is smaller than a first wheel speed threshold value, and the difference value of the wheel speeds of two driving wheels is smaller than a second wheel speed threshold value last for second preset duration, the angle of an angle sensor at the finishing moment of the second preset duration is calibrated as a steering wheel angle median, and the calibration value is recorded.The steering wheel angle median value can be updated in real time, accordingly, more precise angle signals are provided for the steering system, and safety performance and manipulating comfort of vehicle traveling are improved.

Description

technical field [0001] The invention relates to the field of automobiles, in particular to an electric power steering system with the function of self-learning the center of the steering wheel angle. The invention also relates to a method for self-learning the center position of the steering wheel angle of the electric power steering system. Background technique [0002] Automotive electric power steering system structure, such as figure 1 As shown, it is composed of a traditional mechanical steering system with an additional rotation angle & torque sensor 2, an electronic control unit 12, a power steering motor 11 and a reduction mechanism 4 thereof. A traditional mechanical steering system mainly includes a steering wheel 1 , a steering column 3 , an intermediate shaft 5 , a steering gear 6 , a pinion 10 , a tie rod 7 , a steering knuckle arm 9 and a steering wheel 8 . Among them, the torque sensor 2 is used to detect the driver's steering torque; the power assist motor ...

AI Technical Summary

Problems solved by technology

The method of manual calibration has the following disadvantages: First, it increases labor costs

Second, accurate calibration requires four-wheel alignment, which has certain requirements for the calibration environment.

Third, after replacing the corresponding parts, it also needs to be re-calibrated, which increases maintenance costs

Fourth, the precision requirements for parts are high, otherwise it will cause left-right asymmetry and affect the steering feel. In extreme cases, the wrong zero position of the steering wheel will also increase driving risks and cause loss of life and property

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