Research On The Design And Characteristics Of Steering-By-Wire System

The Steering-By-Wire system, because it has cancelled the mechanical connection between the steering-wheel and the steering-tire, not only enlarge the ride space, but also the cab design becomes more free and flexible. Meanwhile, the steering transmission ratio can be changed according to the demands. All of these will contribute to the further research on the active control of the steering system. Thus it will surely become one of the trends in the research and design of steering system in the future. Nowadays, researchers pay more attention to the development of steering by wire system.The history of automobile steering system has experienced mechanical steering system, hydraulic power assisted system, electronic control hydraulic power steering system and electric power steering system. The steering efforts of drivers taken in mechanical steering system are large. In order to reduce the driver's labor, several steering system with assist characteristics were developed. The main function of steering system is to fulfill the driver's command. At the same time, it must have good road feel, in another word, it must has good steering force characteristics to alert the driver about the situation of the automobile. In the research of the assist steering system, one of the main works is to analyze the steering force characteristics. With the development of science and technology, the application of new methods and control systems, such as the new sensor used in automobile engineering, steering-by-wire system will be developed sharply. It not only can realize the good steering force characteristics but also can provide the basis for the further active control. For the instance, the steering-by-wire system with the stability control system equipped in automobile can improve the safety greatly under high speed and limit working conditions. Because of the indirect connection between steering wheel and the mechanical steering structure, it gives more challenge on the research of steering-by-wire system.With the application of computer simulation technology, the characteristics of steering-by-wire system were analyzed in this paper. Firstly, the performance of the mechanical steering system of a type of automobile was investigated under several typical working conditions by the built whole automobile model, especially, the steering force characteristics. The control strategy for the further research on steering-by-wire system is fitted through using the steering force characteristics and some motor parameters. The steering force characteristics of steering-by-wire system and some other dynamic parameters can be obtained through the co-simulation between ADAMS and Matlab platform under the same several typical working conditions used in assessing the performance of mechanical steering system.The main research includes the following five aspects.The fist section introduces the development and the current situation of automobile steering system. It also gives the information about steering-by-wire system on the situation, the development.The second part mainly illustrates the use of ADAMS platform, such as the important models that used in the ADAMS software and the basic theory of the analysis of the ADAMS kinematics. The possible causes of the numerical value non-convergence are presented and the critical skills in solving the problem are analyzed.The third section gives a brief introduction of the construction of full automobile model with 14 DOFs when using ADAMS. The full model includes the chassis model, the front suspension, the rear suspension, the steering system, the tire model and the file of road properties.The forth section puts a high emphasis on the sub-system construction of the steering-by-wire and it's working principle for road feeling and the steering actuator dynamic model which includes the steering-by-wire system in the full vehicle and it's key technology.The fifth section makes an elaboration on the typical working conditions such as steady static circular test, the steering wheel sine-wave input test, pylon course slalom test and the ISO double lane change test that are used in evaluating the steering characteristics of the steering-by-wire system. The numerical results from the mechanical steering system are compared with the results form the steering-by-wire system under the four typical working conditions in steering characteristics. The conclusion can be drawn by the comparison that the design of the steering-by-wire system is reasonable and the control strategy is valid.Finally, the section summarizes the research works and makes a discussion of the problems existed in the paper. The co-simulation of ADAMS and MATLAB has wide application prospect. The binding of the two platforms can exert each advantage. It can make the virtual prototype simulation more powerful and becomes more widely used in many fields.