形状记忆合金(SMA)弹簧驱动器的变形研究

Research on deformation of SMA spring actuators

建立了可作为软体机器人中的形状记忆合金(SMA)弹簧驱动器的变形模型,获得了模型的待定参数A1、A2、A3、B1、B2、B3,并对该模型进行了实验验证。首先基于Clausius-Clapeyron方程和泰勒展开式,使用待定参数法建立了SMA弹簧的变形模型,描述了SMA弹簧的变形量、负载和温度之间的非线性关系;然后根据热平衡方程建立了电加热情况下的SMA弹簧温度变化模型,并获得了加热时间与弹簧温度的关系曲线;继而进行了零负载状态下的变形实验,根据实验结果计算出变形模型中的待定参数;最后通过定长通电驱动和定载荷通电驱动实验,验证了模型的正确性。所建模型能够为软体机器人中的SMA弹簧驱动器的控制方案建立提供参考。

A deforming model of shape memory alloy （SMA） spring actuators applicable to soft robots was built with its undetermined parameters of A1, A2, A3, B1, B2 and B3 being obtained, and some experiments were performed to verify the model. Firstly, the undetermined parameter method was used to build a deforming model of SMA springs based on the Clausius-Clapeyron equation and Taylor expansion, and the nonlinear relations among SMA springs＇ deformation, load and temperature were described. Secondly, based on the heat balance equation, a temperature changing model of SMA springs under electric heating was built, and a curve was shown to describe the relationship between the heating time and the spring temperature. Thirdly, the deforming experiment was performed in the condition that spring is free. Lastly, the models＇ validity was verified through specified load experiments and specified deformation experiments. The established models were proved to be referential for building the controlling system of soft robots.