Application of Bond Graph Technique and Computer Simulation to the Design of Passenger Car Steering System

Vehicle Dynamics play an important role in responsiveness of a vehicle. The performance of a vehicle depends on its ride and handling characteristics [1]. Handling is a measure of the directional response of a vehicle and one of the important characteristics from the vehicle dynamics point of view. The directional response of a vehicle depends on the dynamics of the steering system. A good steering control provides an accurate feedback about how the vehicle reacts to the road. In this paper, the powerful techniques of Bond graphs and state equations [2] are used to design and analyze the dynamics of a manual rack and pinion steering system. The author obtains the transfer function between the Angle of rotation of front tire and the Angle of rotation of steering wheel. The overall steering ratio of the bond graph modeled steering system is compared with the overall ratio of a similar vehicle to validate the model.

The Characteristic equation of this system was derived to understand the damping frequency and damping ratio. The natural frequencies and the Eigen values of the steering system are computed and analyzed for its stability. A frequency analysis is carried out on the system to determine the magnitude and phase lag of the system at different frequencies.

This paper elaborates the influence of various parameters in controlling the response characteristics and MATLAB is used to validate the results.