Recirculating-ball electric power-assisted steering system with variable transmission ratio for bus and control method thereof

Abstract

The invention relates to a recirculating-ball electric power-assisted steering system with variable transmission ratio for a bus, belonging to the field of steering systems for buses. The system sequentially comprises a steering wheel, a steering column, a torque transducer, a power-assisted motor, a first retarding mechanism connected with the power-assisted motor, a recirculating-ball steering gear, a steering rocker shaft arm, a steering tie rod and a steering system control ECU, wherein a second retarding mechanism and a corner motor driving the second retarding mechanism are arranged between the torque transducer and the recirculating-ball steering gear. The corner motor control integrates the ideal transmission ratio control with the stability control for carrying additional corner control, thereby changing the transmission ratio from a steering wheel corner to a front wheel corner, and increasing the function of the steering wheel in the stability control; meanwhile, steering counter torque complementation control caused by the additional corner is integrated into the power-assisted control of the power-assisted motor, thereby realizing the coordination control and the matching of the corner motor and the power-assisted motor and ensuring that a driver obtains better steering handfeel.

Description

technical field [0001] The invention relates to a passenger car steering system, in particular to a recirculating ball electric power steering system of a passenger car. Background technique [0002] At present, the existing recirculating ball electric power steering system for passenger cars only provides variable power assistance according to the driver's steering operation intention to reduce the driver's steering burden. However, it is not possible to implement active correction control according to the requirements of vehicle operating conditions for handling stability, nor can it compensate for the driver's steering misoperation. In particular, in the existing passenger car recirculating ball electric power steering system, the transmission ratio from the steering wheel angle to the front wheel angle is fixed. Turn the steering wheel at a large turning angle, but the requirement of low steering sensitivity cannot be met at high speed, otherwise the stability and safet...

AI Technical Summary

Problems solved by technology

[0002] At present, the existing passenger car recirculating ball electric power steering system only provides variable power assistance according to the driver's steering operation intention to reduce the driver's steering burden

It cannot implement active correction control according to the requirements of vehicle operating conditions for handling stability, nor can it compensate for the driver's steering misoperation.

In particular, in the existing passenger car recirculating ball electric power steering system, the transmission ratio from the steering wheel angle to the front wheel angle is fixed. Turn the steering wheel at a large turning angle, but at high speeds, the requirements for low steering sensitivity cannot be met, otherwise the stability and safety of the vehicle will decline accordingly

Therefore, the existing passenger car recirculating ball electric power steering system cannot meet the requirements of low-speed sensitivity and high-speed stability at the same time

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