This study investigates the possibility of realizing controlled wheel motion for an active suspension using a class of smart materials, namely piezoceramics. The proposed concept deviates significantly from conventional practice of using heavier, hydraulic actuators. Rather than accomplishing the wheel motion using the direct stroke of an actuator, the motion is to be realized by actively modifying the effective stiffness of the suspension system using piezoceramic sensing and actuation. Piezoceramic actuators have been typically waived as totally unacceptable for such large stroke, load carrying applications, since these actuators have always been limited to micro-motion ranges. A strategic combination of elastic and piezoceramic layers is shown to have the potential to meet this challenge. Preliminary analysis and experimentation have been conducted in order to demonstrate the feasibility of the concept. A candidate design is analytically investigated using composite piezoceramic suspension elements. It is shown that piezoceramic actuation has the potential to control suspension system deflections through sufficient motion ranges. A prototype actuator demonstrating larger stroke actuation has also been designed, fabricated, and tested.
Abstract