Study of the Vehicle Controllability and Stability Based on Multi-body System Dynamics

Abstract

In this paper, the 135 Degree of Freedom multi-body system dynamics model was built by using the software ADAMS/CAR, according to the requests of Chinese standards, and the simulating research about 6 performances of automotive controllability and stability were carried on. Based on the simulating results, some automobile’s performance, such as return-ability, slalom-ability and steering efforts-ability, were excellent, but some other performances, such as steady state cornering ability, steering wheel angle pulse input response ability and steering wheel angle step input response ability, were not satisfied. In order to improve the performance of the automobile, three parameters, i.e. the automotive mass, the load of front axis and the torsion stiffness of rear stabilizer anti-roll bar, were selected as the optimized objects. Within the variety range of the parameters, the multi-body system of the automobile was optimized. Automotive controllability and stability is improved obviously based on the simulating results of the optimized multibody system.

Influence of Clearance on the Rocker Arm Pin on the Steerability and Stability of the Vehicle Motion

“…The response time t r of the vehicle was considered to be an important factor in determining the steerability of the vehicle [16][17][18]. It depends on cornering stiffness of tires, the weight of the vehicle, and the speed of its movement:…”

The influence of degree of loading and load placing on steerability of vehicles

“…The dependence (15) is the basis for determining the dynamic angular stiffness (similar to static) of the tire c ω relative to the vertical axis c ω =kG k , the coefficient k is determined by empirical dependence. At the same time, the moment of dynamic resistance of the tire rotation, provided that the latter is proportional to the angle of rotation of the tire [1], takes the following form:…”

“…( ) where Θ -the angle of rotation of the steered wheel relative to the axis of the pin (the axis relative to which the wheel rotates). The condition of steerability of a wheeled vehicle (taking into account the oscillations of the sprung part and the variable of speed motion dV/dt=w takes the form M φ ≤ M φ max , where M φ max -the limit value of the coupling torque resistance of the tire which occurs when the sliding of the tire elements that are in contact with the supporting surface [1].…”

“…Steerability and stability of motion of wheeled vehicles characterize to some extent the ability to change the direction of safe motion of a vehicle and keep it due to a driver's action on a steering wheel [1]. The main value that determines these characteristics (steerability, stability of motion, passability) in the end, is the loading on a tire and the forces of its interaction with the road pavement, etc.…”

“…Such questions are the subject of this research. Also, when considering the influence of the dynamics of the sprung mass of a wheeled vehicle on the limit values of the angle of steerability and the speed of stable motion, it is assumed that the elastic force characteristics of the suspension system are described by a nonlinear ratio [1][2][3], which more accurately reflects the real picture of the process of the sprung part.…”