Automotive engineers and analysts using tire models to simulate vehicle dynamics; Tire engineers, chassis engineers, vehicle dynamics engineers; Graduate students and researchers working on tire and vehicle dynamics; Aeronautical engineers working on landing gear.
This paper investigates integrated vehicle dynamics control through coordinating active aerodynamics control, active rear steering, torque vectoring and hydraulically interconnected suspension for improving the overall vehicle performance including handling, stability, and comfort. After developing each chassis control system, it is tested by various manoeuvres in order to assess each subsystem. Then, a rule-based coordinate system is proposed for integrated control of the four chassis control systems. Simulation investigation is performed to display the effectiveness of the proposed integrated vehicle dynamics system. Results demonstrate that the proposed control scheme is able to enhance the multiple performance indices of the vehicle including both the ride comfort, and the lateral stability, compared to the non-integrated control system.
The Pacejka tire models are widely used in professional vehicle dynamics simulations, and racing car games, as they are reasonably accurate, easy to program, and solve quickly. A problem with Pacejka's model is that when implemented into computer code, it doesn't work for low speeds (from around the pit-entry speed), because a velocity term in the denominator makes the formula diverge. An alternative to Pacejka tire models are brush tire models, which can be analytically derived, although empirical curve fitting is still required for good correlation, and they tend to be less accurate than the MF models.
A new way of representing tyre data obtained from measurements in pure cornering and pure braking conditions has been developed in order to further improve the Dynamic Safety of vehicles. The method makes use of a formula with coefficients which describe some of the typifying quantities of a tyre, such as slip stiffnesses at zero slip and force and torque peak values. The formula is capable of describing the characteristics of side force, brake force and self aligning torque with great accuracy. This mathematical representation is limited to steady-state conditions during either pure cornering or pure braking and forms the basis for a model describing tyre behaviour during combined braking and cornering.
In this new paperback edition of Tire and Vehicle Dynamics, theory is supported by practical and experimental evidence. Pacejka provides both basic and advanced explanations of the pneumatic tyre and its impact on vehicle dynamic performance. The book shows the way in which tyre models are incorporated in vehicle models and how important tyre influence is on overall vehicle behaviour. Those working in any industry involving equipment with tyres will continue to find this book both extremely relevant and useful.
In this well-known resource, leading tire model expert Hans Pacejka explains the relationship between operational variables, vehicle variables and tire modeling, taking you on a journey through the effective modeling of complex tire and vehicle dynamics problems.
This chapter is meant to serve as an introduction to vehicle dynamics with emphasis on the influence of tire properties. Steady-state cornering behavior of simple automobile models and the transient motion after small and large steering inputs and other disturbances will be discussed. The effects of various shape factors of tire characteristics (cf. Figure 1.1) on vehicle handling properties will be analyzed. The slope of the side force Fy vs slip angle α near the origin (the cornering or side slip stiffness) is the determining parameter for the basic linear handling and stability behavior of automobiles. The possible offset of the tire characteristics with respect to their origins may be responsible for the occurrence of the so-called tire-pull phenomenon. The further nonlinear shape of the side (or cornering) force characteristic governs the handling and stability properties of the vehicle at higher lateral accelerations. The load dependency of the curves, notably the nonlinear relationship of cornering stiffness with tire normal load, has a considerable effect on the handling characteristic of the car. For the (quasi)-steady-state handling analysis, simple single track (two-wheel) vehicle models will be used. Front and rear axle effective side force characteristics are introduced to represent effects that result from suspension and steering system design factors such as steering compliance, roll steer, and lateral load transfer. Also, the effect of possibly applied (moderate) braking and driving forces may be incorporated in the effective characteristics. Large braking forces may result in wheel lock and possibly large deviations from the undisturbed path. The motion resulting from wheel lock will be dealt with in an application of the theory of a simple physical tire model in Chapter 3 (the brush model). The application of the handling and stability theory to the dynamics of heavy trucks will also be briefly dealt with in this chapter. Special attention will be given to the phenomenon of oscillatory instability that may show up with the car-trailer combination. 2b1af7f3a8