Tensegrity-inspired Multi-axis Positioning SMA Actuator

This paper presents the design of a multi-axis positioning actuator based on shape memory alloy (SMA) wires inspired by tensegrity structure. Our actuator is composed of SMA wires, supporting elements, and the central axis. The tension of SMA wires maintains floating compression without central support. The proposed actuator provides multi-axis positioning and bidirectional motion by antagonistic SMA wires through alternate Joule heating and natural cooling. The actuator can be recovered relatively fast by twisting the SMA wire which significantly enhances the recovery force of SMA. The output characteristics of the actuator are experimentally presented by measuring under a temperature change (from 36°C to 90°C).