Hierarchical system used for four-wheel-hub motor-driven electric automobile, and control method

Abstract

The invention discloses a hierarchical system used for a four-wheel-hub motor-driven electric automobile, and a control method. First of all, yaw moment is calculated as a yaw moment decision-making layer according to a vehicle speed sensor, a steering wheel rotary angle transmitter, an electronic throttle sensor and an inertia measurement unit; then according to automobile longitudinal force constraints, yaw moment constraints, a maximum adhesion force which can be provided by a pavement and restrictions of motor maximum output moment, target torque of each wheel hub motor is calculated as a target optimization analysis layer; and finally, degrees of similarity to six standard pavements are obtained by inputting two parameters, i.e., an adhesion coefficient and a wheel slip rate into a pavement adhesion coefficient estimation fuzzy controller by means of a current pavement, and an adhesion coefficient estimated value of the current pavement is obtained as a pavement adhesion coefficient monitoring layer after weighted averaging is performed. According to the invention, whole-vehicle stability is taken as a control target, motor torque is reasonably distributed according to operation working conditions, and the controllability, the stability and the economic property of vehicles are improved.

Description

technical field [0001] The invention belongs to the technical field of intelligent control of electric vehicles, and in particular relates to a layered system and a control method for electric vehicles driven by four-wheel hub motors. Background technique [0002] In recent years, due to the increasingly prominent dual issues of environmental protection and energy security, electric vehicles have once again jumped into people's field of vision. Since electric vehicles use high-efficiency rechargeable batteries, zero exhaust emissions during operation can greatly reduce environmental pollution. At the same time, compared with traditional fuel-powered vehicles, electric vehicles driven by four-wheel hub motors have the following advantages: First, the torque response speed of the motor is 50-100 times that of internal combustion engines, and the torque and speed of each wheel can be accurately controlled. Secondly, the transmission shaft, clutch and other mechanisms are remov...

AI Technical Summary

Problems solved by technology

Its control effect can meet the stability control requirements in general road conditions, but when the four-wheel-drive electric vehicle is turning, high-speed, or on a bad road, the effect of these control methods often fails to meet our expectations

In addition, when various decentralized safety control systems work at the same time, the coupling effect between the control systems will also occur and the control effect will be reduced.

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