Design of Active Suspensions

Abstract

The synthesis method is employed for the design of servo-suspensions of the electro-hydraulic type. Two alternative arrangements are considered in which the hydraulic actuators and the body support springs are respectively in series and in parallel. The achieved designs for active suspensions of this type are superior to conventional systems both in ride quality and in overall stiffness to resist body load forces, but slightly less effective in regard to road-holding. If dynamic absorbers are used for the control of axle vibrations it is shown that considerably greater improvements in ride quality than hitherto possible may be obtained with the aid of an additional feedforward compensating signal flow path. The derivation of the necessary compensation circuits to achieve the specified overall system performances is demonstrated by examples. A simple method of banking control of the vehicle by inclined sensing accelerometers is suggested.