Initial Estimates in the Design of Rack-and-Pinion Steering Linkages

Abstract

Based on recent results concerning the occurrence of function cognates in Watt II linkages, it is shown that only 3 geometric parameters are sufficient for defining the kinematic function of simplified planar rack-and-pinion steering linkages. The steering performances of the mechanisms are analytically expressed in terms of these parameters and, by employing an optimization-based synthesis method involving increasing the degree of freedom of the mechanism, the optimum domains are determined. The parameter sets corresponding to these minimum steering error domains are displayed in design charts. These charts aid the automotive engineer in the early stages of conceiving a new steering linkage by providing initial estimates of the basic geometry of the mechanism. They also provide information on two other characteristics of concern, i.e. the minimum pressure angle occurring in the joints and the rack stroke required for maximum turn of the wheels. [S1050-0472(00)00402-5]

Steering System Kinematic and Steady-State Cornering Analyses of the ITS Electric Car

“…Let redraw the side take-off steering linkage for S kinematic analysis as shown in Figure 3(a). These linkages noted has an infinite number of cognates [4], meaning that the input-output link behaviors of all the cognate linkages are same. Further, the steering linkage shown in Figure 3(a) can be represented as shown in Figure 3(b) which is the cognate of that shown in Figure 3(a).…”

“…Hence, an appropriate kinematic model of the steering linkage is essential. Steering linkages have received a lot of attention from the kinematics point of view because of its influence on the Ackermann error [4]. Less attention is paid to its dynamics apparently caused by the fact that the pinion rotates at low speed, typically 10-15 rpm [1].…”

“…Real steering mechanisms are complex spatial linkages. However, the kingpin inclination and caster angles that provide compliance to the steering linkage with the suspension system have little influence on the motion transmission of the steering linkage [4]. As a result, the real rack and pinion steering linkage, which is spatial in nature, can be modeled as a planar linkage for the investigation of Ackermann condition.…”

“…Such a simplification of the steering system has been also used by other researchers, e.g. ( [4]; [2]).…”

Analysis and Optimization of the Double-Axle Steering Mechanism with Dynamic Loads

“…China; Tel/Fax: +86-27-87547405; E-mail: zhangyq@hust.edu.cn parameters to optimize the steering errors of the central-lever steering mechanism of a vehicle. Simionescu and Smith [7] introduced parameter design charts with three parameters, namely, a normalized link length, a link length ratio and two angles, in the case of central take-off/Side take-off configuration to optimize the steering errors of the linkages. However, the choice of the design parameters used, some of which were expressed by angle variables, was not appropriate for link-length sensitivity analysis.…”