Vehicle and control method and control device of electric power steering system of vehicle

Abstract

The invention provides a vehicle and a control method and device of an electric power steering system of the vehicle. The electric power steering system comprises a power-assisted motor, and the control method comprises the following steps of obtaining the steering wheel angle, the vehicle speed and the rotating speed of the power-assisted motor; judging a damping compensation direction accordingto the steering wheel angle and the rotating speed of the power-assisted motor; obtaining damping compensation current according to the vehicle speed, the damping compensation direction and the rotating speed of the power-assisted motor; obtaining the steering torque of a steering wheel, and obtaining the target output current of a power-assisted motor according to the damping compensation current, the steering torque and the vehicle speed; and controlling the power-assisted motor according to the target output current. According to the control method, a damping compensation direction judgmentlink based on the rotating direction of the steering wheel is added, the control precision of the power-assisted motor can be improved, the damping compensation effect of the power steering system isguaranteed, and the driving experience of a driver is improved.

Description

technical field [0001] The invention relates to the technical field of vehicles, in particular to a control method and a control device for a vehicle and its electric power steering system. Background technique [0002] The steering motor and deceleration mechanism in the EPS (Electronic Power Steering) system will introduce unnecessary damping to the steering system. In order to reduce its negative impact, it is necessary to add damping compensation. At present, in the prior art, the judgment conditions and control strategies for the damping compensation control mostly rely on the vehicle speed and the motor speed as the damping compensation control signals to control the damping compensation. That is, PI (Proportional-Integral, proportional-integral) adjustment is performed on the motor speed and vehicle speed to obtain an estimated damping compensation current value, and establish a follow-up relationship between the three, so that the damping compensation current value ...

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Problems solved by technology

[0003] However, the above-mentioned control strategy does not fully consider the uncertain factors that may be brought about by the actual driving conditions: the driver’s operation on the steering wheel will be more complicated when the vehicle is actually driven, for example, the steering wheel may also return to normal when the vehicle is driving at a constant speed. In the operation of frequent switching between steering and normal steering, if only the absolute value linear relationship between the motor speed, vehicle speed and damping compensation value is determined without considering the direction factor of damping compensation, that is, the direction of damping compensation is determined according to the direction of steering wheel rotation, it will be very difficult. It is difficult to achieve precise steering control effect, and may even cause hand force fluctuations at the junction of the steering wheel steering limit position and the steering wheel steering middle position, affecting the driver's driving comfort

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