Self-Resetting Design of an SMA-Actuated Lock and Release Mechanism for Space Applications

Advancements in space technology have increased the demand for reusable lock and release mechanisms. These mechanisms must undergo repeated cycles of locking and releasing during ground testing. However, in some spacecraft, the lock and release mechanism is fitted in a small space, making it difficult to dismantle it several times or reset it with tools, so there is an urgent need for lock and release mechanisms with self-resetting characteristics. This paper proposes a novel self-resetting lock and release mechanism actuated by shape memory alloy (SMA) wires. Through the design of SMA wire coupled with reset spring, the moving components within the mechanism can automatically return to their initial state after release, enabling repeated locking and releasing. Compared to existing manual reset mechanisms, this design offers simpler operation and supports rapid deployment. The mechanism weighs only 238 g and has an envelope size of 62 mm in diameter and 48 mm in height. Experimental tests and analysis show that the proposed mechanism can achieve the self-resetting lock and release function at least 50 times under a load of 10 kN. Furthermore, experimental tests have shown that, at a current of 3 A, the proposed mechanism can release within 0.7 s under a 10-kN load.