Interconnected vehicle suspension

This paper introduces a class of passive interconnected suspensions, defined mathematically in terms of their mechanical admittance matrices, with the purpose of providing greater freedom to specify independently bounce, pitch, roll, and warp dynamics than conventional (passive) suspension arrangements. Two alternative realization schemes are described that are capable of implementing this class (under ideal assumptions). The first scheme incorporates an interconnected multilever arrangement consisting of four separate hydraulic circuits, which transforms the separate wheel station displacements to bounce, pitch, roll, and warp motions. Four separate mechanical admittances are connected across the transformed terminals of the multilever. The second scheme is kinematically equivalent to the first but the multilever part consists of four modular subsystems to achieve the same kinematic transformation. The purpose of the class is to allow a high degree of independence between the modes of vehicle motion, e.g. low warp stiffness independent of front and rear anti-roll stiffness. Practical issues that might be involved in implementing the realization schemes are discussed, as well as generalizations to two-and six-wheeled vehicles. 1 INTRODUCTION 'mechanical transformer' (multilever), which connects the wheel stations to four mechanical admittances This paper introduces a class of passive inter-(e.g. parallel spring–dampers). The mechanical trans-connected suspensions, defined in terms of their former consists of four independent hydraulic circuits four-port mechanical admittance matrices, with the that serve to transform the combined wheel station purpose of providing greater freedom to indepen-motions into generalized deflections, which may dently specify bounce, pitch, roll, and warp dynamics represent bounce, pitch, roll, and warp motions, etc. than conventional (passive) suspension arrange-In the second realization approach, a method is ments. A feature of the class is that several desirable described to replace the hydraulic multilever with a objectives may be achieved together, e.g. low warp modular system consisting of four subcomponents, stiffness independent of front/rear roll stiffnesses which are separately realized. In principle this is and increased anti-pitch stiffness independent of dynamically equivalent to the first arrangement, bounce response. In contrast, a number of the exist-but it allows alternative possibilities in terms of ing approaches to achieve low warp stiffness do so packaging on the vehicle. For example, the sub-at the expense of roll resistance being provided pre-components may be separately located within the dominantly at only one end (front or rear) of the car, vehicle. Alternatively, they may be combined together which has a particular disadvantage for handling. into one central suspension unit. …