Self-locking SMA Actuator for Optical Zoom in Smartphones

This paper presents a novel self-locking Shape Memory Alloy (SMA) actuator for an optical zoom function in smartphones. Two antagonistic SMA wires implement two separate linear movements – one for the positioning of the optical element, and the other for its locking and unlocking. The concept and mechanical design of the actuator are introduced, followed by a brief explanation of the simulation model used in the model-based design approach. For experimental investigation, a heavily instrumented functional model (4:1 scale) was realized. Simulation and experimental data generally correlate well and prove the presented concept.