A novel binary actuator using shape memory alloy

Abstract

In situations that demand the use of the high-bandwidth, high-quality sense of vision for interactions with the physical world it would be beneficial to have a wearable tactile display that takes advantage of touch to communicate information to the user without causing visual distractions. This thesis presents the design and development of a novel actuator that can be configured into thin, flexible arrays to meet this need for wearable tactile displays. The actuator presented uses the strain recovery property of the martensitic transformation of Nitinol, a Shape Memory Alloy (SMA), to generate the actuation force. A compliant bistable mechanism provides the restoring force that pre- strains the martensitic Nitinol, and thus makes the actuator binary. Binary actuation alleviates some of the problems that would otherwise limit the effectiveness of Nitinol in wearable haptic systems. To increase the potential for commercial success, manufacturability issues are considered throughout the development cycle to ensure the potential for economical large scale production. The paper concludes with the presentation of three different prototypes. Their successes and failures are discussed along with recommendations for future work.