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An existing kinematic model is discussed in this paper for its suitability for the kinematic analysis and synthesis of five-link rear suspension mechanism of a passenger car. The formulations for the trajectory of wheel center and contact patch along with other basic suspension kinematic parameters, as a function of wheel jounce and rebound are discussed and simulated. A model of the suspension is built in Multi-body Dynamics software ADAMS/view to validate the discussed model. The simulation results of kinematic model are found to be influenced by magnitude of the assumed velocity component of wheel center, however when a small magnitude of velocity is assumed as the input to the model the results match with the ADAMS model. A sensitivity analysis method is discussed in this paper which reveals the influence of suspension joint locations on the wheel center trajectory and other kinematic parameters. The information obtained from the sensitivity analysis can be effectively used for tuning of the hard points to obtain desired kinematic parameters. Using the results of sensitivity analysis, two of the hard points of an existing suspension are relocated and was verified by kinematic analysis of the modified suspension that the modification had resulted in an improved camber variation with a slight compromise on ride height.

This paper presents the study of influences of damper asymmetry together with the suspension kinematics and tyre lateral compliance on the vehicle performance considering a roll-plane model. A 4-DOF, roll-plane model of the road vehicle employing a double wishbone suspension comprising a strut with linear spring and asymmetric damper is formulated for the analyses. The sprung-mass vertical acceleration, chassis roll angle, dynamic tyre forces and the tyres camber angle variation responses of the model with asymmetric dampers are compared with those of the model with an equivalent linear damper under bump and pothole inputs, and rounded-step lateral excitations. The results suggested that the responses are complex functions of damper asymmetry ratio, defined as the ratio of damping coefficient in rebound to that in compression, vehicle forward speed and type of input. The study further suggests that a very low compression mode damping is undesirable from both ride and handling dynamic perspectives.Reference to this paper should be made as follows: Balike, K.P., Rakheja, S. and Stiharu, I. (2013) 'Kineto-dynamic performance analysis of vehicle with an asymmetric suspension damper using a roll-plane model', Int.

Asymmetric dampers invariably employed in automotive suspensions are known to cause ‘damper jacking’. The influence of the damper jacking on the suspension kinematic responses, particularly variations in the camber angle, are generally ignored while synthesizing a damper. This study presents influences of damper asymmetry on the camber angle variations of a double wishbone type of suspension together with the dynamic responses under measured urban road inputs. Simulation studies employing a kineto-dynamic quarter-car model comprising a bilinear damper revealed increase in the camber angle variations with an increase in the damper asymmetry, while this increment showed nonlinear relation with the suspension deflection. This study further investigates synthesis of an optimal two-stage asymmetric damper to yield a compromise between the conflicting performance measures. A composite performance index comprising the ride comfort and road holding measures with limit constraint on camber angle variation is formulated to seek optimal damper parameters. The results are presented so as to yield design guidance for synthesis of asymmetric dampers.