Automobile steering-by-wire system and control method thereof

Abstract

The invention discloses an automobile steering-by-wire system and a control method of the automobile steering-by-wire system. The automobile steering-by-wire system can control the angle of a steering wheel accurately, and a location servo mode of a road sense motor is adopted for limiting the steering angel of the steering wheel instead of a common mechanical limiting mechanism. Double steering motors adopt a redundancy design, simultaneously receive same control instructions sent by a master controller and work in a location servo control mode to drive a steering gear, and therefore not only is reliability of the system ensured, but also the angle of the steering wheel can be controlled accurately. Three-phase alternating current asynchronous motors are adopted for the road sense motor, the first steering motor and the second steering motor, therefore, even if a winding short circuit fault happens, damping torque can not be generated, and safety and reliability of the system are improved. Road sense coefficients of road sense feedback torque can be adjusted according to needs, personalized configuration of road sense intensity is achieved, and driving comfort is improved.

Description

technical field [0001] The invention relates to a mechanism in the technical field of vehicles, in particular to an automobile steering-by-wire steering system and a control method thereof. Background technique [0002] The stability of the automobile steering system directly affects the handling stability of the automobile, and further affects the comfort and safety of the driver and passengers, so the performance of the automobile steering system is also an important part of the active safety of the automobile. After the automobile steering system has gone through the development stages of hydraulic power steering system (HPS), electrohydraulic power steering system (EHPS) and electric power steering system (EPS), wire control electric power steering system (SBW) is gradually becoming the Research hotspots of major automakers and research institutions. [0003] Although the electric power steering system has been widely used at this stage, there are still some problems: ①...

AI Technical Summary

Problems solved by technology

[0003] Although the electric power steering system has been widely used at this stage, there are still some problems: ①The mechanical connection between the steering wheel and the steering wheel brings great inconvenience to the layout of the vehicle, and at the same time, when the vehicle has a traffic accident, the steering The existence of pillars will cause serious harm to the driver's personal safety; ②The transmission ratio of the steering system is fixed, and the transmission ratio cannot follow the change of the vehicle speed, which limits the maneuverability of the vehicle; ③The road feeling information obtained by the driver is relatively fixed and cannot be realized. Personalized operation of the vehicle; ④ There are many mechanical transmission mechanisms between the steering wheel and the wheels, the system inertia, system friction and the total gap between transmission components are large, and the response speed and control accuracy of the system are poor; ⑤ Generally difficult to achieve Precise control of the steering angle of the steering wheel, it is difficult to realize the cruise control of the vehicle

After summarizing various materials, the following problems still exist in the electric power steering system by wire control in the prior art: ① A single steering motor is generally used, and there is no hardware redundancy design, so the reliability of the system is difficult to guarantee; ② The steering motor and Road induction motors generally use DC motors, DC brushless motors, permanent magnet synchronous motors and other motors with permanent magnet structures. Although the control of such motors is simple, once a fault such as winding short circuit occurs, a lot of damping torque will be generated, which will seriously affect The safety of the vehicle and the driver; ③Steering motors generally use torque control algorithms, which cannot achieve precise control of the steering wheel angle, and it is difficult to achieve cruise control of the vehicle

④ There is no steering wheel steering angle limiting mechanism, or a mechanical steering wheel steering angle limiting mechanism is adopted, and the steering wheel steering limit angle is fixed and cannot be flexibly configured

The above characteristics of the steer-by-wire system seriously restrict the performance of the steering system and limit the popularization and application of the steer-by-wire system

Images