Active Vibration Isolation of Rear-View Mirrors Based on Piezoceramic „Double Spiral“ Actuators

Abstract

For safety and comfort reasons, rear-view mirror vibrations have to be reduced. The sources of those vibrations are vehicle body vibrations and aerodynamic forces. This paper shows that an enhanced infinite stiff mirror system would not solve the vibrating mirror problem because the vibrations that are induced by the vehicle body would still excite the mirror. To solve this problem conventionally, a re-design of both the mirror system dynamics as well as the vehicle dynamics would be needed. To prevent such a cost intensive process this paper investigates novel active, multi axial vibration isolation interfaces that have an elastic behavior towards base plate vibrations and provide in parallel high stiffness with respect to external loads. Based on low stiffness double spiral interfaces with attached piezoelectric patch actuators it is shown how these opposed properties can be reached. The use of such interfaces enhances not only the dynamical properties of the mirror, but - in the manner of a truly multifunctional element - it replaces themotor to adjust the mirror position as well. This paper describes the analysis of the complete active isolation system, its actuator design and discusses diverse interface versions.