三自由度介电型EAP软材料位置传感器研究

基于介电型电活性聚合物(EAP)变形时的电容值变化原理,设计并实现一种三自由度软材料位置传感器,其内框可沿平面和法向移动,分别用于检测平面和法向位移。建立该传感器的几何模型,推导出其电容值变化和内框位移的关系。采用差分法测试该传感器的电容值变化,分析了面对面两个传感单元的电容值差和内框的平面位移、单个传感单元的电容值和内框的法向位移之间的关系,测试得到其平面和法向位移灵敏度分别为66.69pF/mm、0.47pF/mm~2,与理论分析结果较吻合。该位置传感器的理论与测试分析结果验证了介电型EAP应用于位置传感器中的可行性。

Research on Three-Degree-of-Freedom Dielectric Electroactive Polymer Soft Position Sensor

Based on capacitance change principle of dielectric electroactive polymer (EAP), a 3 DOF soft position sensor is designed and implemented. The inner frame of the sensor can translate in in-plane and out-of-plane directions, which are used to measure the plane and normal displacement respectively. A geometrical model of the proposed sensor is developed and the relationship between the capacitance of the sensor and the displacement of the inner frame are deduced. A differential approach is used to measure the variation of the capacitance of the sensor, and the relationship between the capacitance difference of two opposite sensing cells and the in-plane displacement of the inner frame as well as the relationship between the capacitance of single cell and the out-of-plane displacement of the inner frame are analyzed. The measured in plane and out-of-plane displacement sensitivity are of 66.69 pF/mm and 0.47 pF/mm2 respectively, which agree well with the analytical results. The theoretical and experimental analyses verify the feasibility of the application of dielectric EAP to the position sensors.