Accurate and simple assembly process of shape memory alloy tubular micro manipulator with a bias mechanism

摘要

This paper describes the fabrication and assembly of a tubular micro manipulator consisting of a TiNiCu shape memory alloy (SMA) actuator with a coaxial tubular bias mechanism of a TiNi super elasticity alloy. The TiNiCu actuator has meandering shaped springs connected to joint rings (O.D.: 970 μm, I.D.: 910 urn) in which a bias mechanism is inserted. To simplify the assembly process, the joint rings have an extendable structure to facilitate insertion of the tubular bias mechanism (O.D.: 900 μm) into the former. Subsequently, the joint rings are locally heated to shrink and clamp the bias spring. The extension and shrinking process facilitated the highly accurate assembly of the tubular SMA manipulator with the bias spring. The assembled manipulator was also strong enough to resist fracture during the bending operation following actuation of the SMA meandering springs.