Three-motor steering-by-wire system and control method thereof

Abstract

The invention discloses a three-motor steering-by-wire system and a control method thereof. The system comprises a steering wheel module, a steering module and an ECU control module. The steering wheel module is used for a driver to operate and control a vehicle to turn, the steering module comprises a first clutch, a third motor, a planet gear mechanism, a second clutch, a first motor, a second motor, a steering gear and a steering rack, ECU in the ECU control module reads the vehicle running speed, a corner signal of a steering wheel, a torque signal of a rotating rod, current fed back by all motor controllers and other signals, the vehicle steering working conditions are analyzed and judged, and then running of all motors and on and off of the clutches are controlled; motor power is subjected to coupling and distribution through the planet gear mechanism and then cooperates with on and off of the clutches, switching of different steering modes of the steering system is achieved, andthen the requirements of the different steering working conditions and the safety of the system are met.

Description

Technical field [0001] The invention relates to the technical field of steer-by-wire technology, and in particular to a three-motor steer-by-wire system and a control method thereof that take into account both response rate and reliability. Background technique [0002] The development of automobile steering system has gone through the following stages: mechanical steering system, hydraulic power steering system (Hydraulic Power Steerting, referred to as HPS), electronically controlled hydraulic power steering system (Electrical Hydraulic Power Steering, referred to as EHPS) and electric power steering system (Electrical Power Steering, referred to as EPS). With the continuous development of control theory and vehicle electronic technology, automotive steering-by-wire (SBW) technology has also become a hot research topic at home and abroad. [0003] As the latest generation of steering system, wire-controlled steering system has obvious technical advantages compared with tradition...

AI Technical Summary

Problems solved by technology

For example, in the control-by-wire system of the Infiniti Q50, when any ECU is detected to have a problem, the standby mode will be activated immediately through a clutch, and the traditional mechanical transmission steering mode will be restored. The problem that the steering system can still work reliably under extreme conditions such as a complete vehicle power failure

Becker et al. proposed an electronically controlled hydraulic steer-by-wire system (patent number US20160068182A1). This device controls the pressure of the steering wheel cylinder through two motor pumps to drive the tie rods on both sides to move left and right, but the response speed of the motor to establish hydraulic pressure is slow. Unreliable factors such as increased oil leakage and air bubbles in the high-pressure oil pipeline, and the direct mechanical connection after the steering-by-wire failure cannot be realized

Yang Lin et al. proposed a hybrid steer-by-wire system (patent number 201610989594.2). In this system, the road sense motor and the power assist motor are separated, and only one set of steering execution motor is used to drive the double-row planetary gear reducer, and then the worm rack drives the horizontal The pull rod moves left and right, and the steering wheel and the steering wheel have real-time controllable force transmission characteristics and angle transmission characteristics. When the system fails, the clutch returns to the mechanical steering state, but the structure of the system is complex and the steering response rate is slow. When frequent changes are required to change the motor direction frequently, the system stability is poor and the service life of the motor is shortened

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