Control of an automotive shape memory alloy mirror actuator

Automobile designers are continuously trying to improve the safety and comfort of new car models. In many cases this translates to the need for less expensive and compact actuators. There are many features that are commonly found in cars that utilize electromechanical type actuators. Power mirrors are one such application that has been becoming more and more standard on cars today. A cost effective mirror actuator was designed and built that utilizes shape memory alloy (SMA) wires to position the external side mirrors. This paper present a second generation SMA-actuated mirror. A robust control algorithm is developed for the mirror to provide stable and accurate positioning. This variable structure controller provides accurate positioning without adding unnecessary complexity to the computational requirements for the mirror. Experimental results are compiled to show the tracking response of the SMA mirror actuator.