Optimal design of SMA linear actuation unlocking mechanism for CubeSat

立方星SMA直线作动解锁机构的优化设计

Received: 21 July 2022

Abstract

In order to realize the reliable unlocking of solar arrays of a CubeSat under the strict constraints of space and power dissipation, a shape memory alloy(SMA) wire linear actuation unlocking mechanism is developed. Through using a spring-SMA structure, relying on the spring force locking, heating the SMA wire and producing a recovery stress drive pin movement, the solar arrays are unlocked. The mathematical model of the unlocking mechanism is established, and the relationship among stroke, unlocking time, power, alloy wire diameter and working voltage of the SMA unlocking mechanism is obtained through simulation. In order to optimize its overall unlocking time and power, the particle swarm optimization algorithm is used to optimize the diameter and working voltage of the alloy wire. The simulation results show that the SMA unlocking mechanism with the wire whose diameter is 0.5 mm has the best working performance when the driving voltage is 1.2 V. Finally, the experimental study of the design results shows that the unlocking time of the actuation unlocking mechanism is 3.2 s, its power is 3.55 W and that its pin-pulling stroke is 1.8 mm, being consistent with the simulation results. The unlocking mechanism has a high reliability, consistent working performance and good adaptability, therefore having passed various environmental tests and being successfully applied to a CubeSat in orbit.

摘要

为实现在空间、功耗严苛约束下立方星太阳板的可靠解锁, 研制了一种形状记忆合金(SMA)丝直线作动解锁机构。采用弹簧-SMA结构, 依靠弹簧力锁紧, 通过SMA丝加热产生回复应力驱动拔销运动实现解锁。建立了机构的数学模型, 并通过仿真得到SMA解锁机构的行程、解锁时间、功率与合金丝直径、工作电压的描述关系。以解锁时间和功率的整体评价最优为目标, 采用粒子群优化算法对合金丝的直径和工作电压进行优化设计, 得到直径0.5 mm的SMA解锁机构在1.2 V驱动电压下具有最佳工作特性。最后对优化结果开展实验分析, 表明作动机构的解锁时间为3.2 s, 功率为3.55 W, 拔销行程为1.8 mm, 与仿真一致。所研制的解锁机构可靠性高, 工作特性一致, 具有较好的适应性, 已通过各项环境实验并成功在轨应用。