整体预紧式六维力传感器动态特性分析

Dynamic characteristic analysis of pre-stressed parallel Stewart structure six-axis force sensor

固有频率作为传感器重要的动态性能指标之一,是传感器动态测试范围的主要确定依据。针对整体预紧式Stewart六维力传感器,基于Kane动力学建模方法及引入角速度算子矩阵,构建了考虑中间预紧分支影响的六维力传感器系统的形式简洁的统一动力学模型。通过忽略系统阻尼,推导得到了传感器系统的简化动力学方程、前6阶固有频率及对应振型。利用有限元仿真软件及对传感器样机进行动态标定实验2种方式分别得到了传感器的固有频率及动态特性指标,并验证了所构建传感器动力学理论建模的正确性。研究内容为传感器在实际动态力监测的应用场合提供了依据,为传感器的产品化设计提供了理论指导。

As one of the important dynamic performance indexes of sensors,natural frequency is the main basis for determining the dynamic test range of the sensors.Aiming at pre-stressed parallel Stewart structure six-axis force sensor,a unified and concise dynamics model of the six-axis force sensor system that considers the impact of the middle preloaded limb is constructed based on Kane dynamics modeling method and through introducing angular velocity operator matrix.The compact dynamic equation,the first six order natural frequencies and corresponding vibration mode shapes of the sensor system are derived by ignoring the system damping.The finite element method （FEM） and dynamic calibration experiment of the sensor prototype were used to obtain the natural frequencies and dynamic characteristic indexes of the sensor respectively; then the correctness of the constructed sensor theoretical dynamics modeling was also verified.This study provides a basis for the application of the sensor in practical dynamic force monitoring and also provides a theoretical guidance for the sensor production design.