Degree Of Freedom Quarter Car Model Research Articles

Stochastic optimal preview control response of a quarter-car nonlinear suspension model using spectral decomposition method

This paper considers a two degree of freedom quarter-car model of a four wheel vehicle with nonlinear spring travelling at a constant speed on a random road surface with a preview control to obtain the optimal vehicle response. The nonlinear spring behavior is assumed as a hysteresis and modelled by the Bouc–Wen model. This nonlinear vehicle model is linearized by using statistical linearization approach. The root mean square values of the control force, suspension stroke and road holding characteristics are determined by spectral decomposition method. The results obtained for the equivalent linearized model using the SDM are validated with Monte Carlo simulation, and the results show that the vehicle performs better using preview control.

Analysis of Dynamic Stability of Nonlinear Suspension concerning Slowly Varying Sprung Mass

In this paper, the stability of vehicle concerning the slow-varying sprung mass is analyzed based on two degrees of freedom quarter-car model. A mathematical model of vehicle is established, the nonlinear vibration caused by sprung mass vibration is solved, and frequency curve is obtained. The characteristics of a stable solution and the parameters affecting the stability are analyzed. The numeric solution shows that a slow-varying sprung mass is equivalent to adding a negative damping coefficient to the suspension system, making the effective damping coefficient change from negative to positive. Such changing parameters lead to Hopf bifurcation and a shrinking limit cycle. The simulation results indicate the existence of static as well as dynamic bifurcation and the result is a change in the final stable vibration of the suspension. Even the tiny vibration of the sprung mass will lead to amplitude mutation, leading to the sprung mass instability.

Development of Passive Quarter Car Suspension Prototype

In this paper, a construction of a prototype to represent passive vehicle suspension system for quarter car model is considered. The prototype is represented by two degree-of freedom quarter-car model which are conventionally used by researchers. This laboratory equipment is developed in order to familiarize students with 2 DoF passive suspension system model. It consists of two masses, two springs and a damper. This equipment is easily dismantled and could be assembled with different spring and damper constants which contribute to different characteristics of the suspension system. A number of experiments have been carried out using the experiment setup in order to identify the suspension system characteristics i.e. experiments with different vehicle body mass, different period for one pulse and different pulse width of input pressure of the road excitation have been conducted. The experiment results are evaluated based on the vehicle body displacement and tire displacement of the prototype. Experiment results show that the pulse width of the input pressure or road profile is directly affected the characteristic of this passive suspension system. Lastly, simulations were done in order to compare the simulation and experimental results.

Establishing the limiting conditions of operation of magneto-rheological fluid dampers in vehicle suspension systems

This paper deals with dynamical behavior of a nonlinear suspension system. We examine chaotic motion in a vehicle suspension system with hysteretic nonlinearity excited by a road profile. A one degree of freedom quarter-car model with nonsymmetric potential is investigated. The Melnikov criterion is used to study the intersection of stable and unstable manifolds and transition to chaos for the system. The condition for chaotic vibration is found using a Melnikov function. Chaotic motion also is indicated by a bifurcation diagram and Lyapunov exponents.