The optimization of passive and controllable suspensions is subject to the constraint that conflicts the car body and tire modes. The application of control systems for improving ride quality has been studied for many years. The control force for an active suspension is derived from either full-state or partial-state signals, which requires extensive hardware, consumes higher energy, and has a low reliability. On-off and variable semiactive suspensions have been used for their simplicity, however they are lack of adaptive capability for nonlinear damping modulation.
The intent of this paper is to apply a fuzzy logic concept for control of semiactive damping that is normally nonlinear with stochastic disturbances. The nonlinear damping coefficient is adjustable in order to control the bounce acceleration, suspension travel and tire deflection. A quarter-car model is used to examine the fuzzy control rule. Results from simulation are presented.