基于力触觉手柄的虚拟环境力反馈交互系统稳定性分析

Stability analysis of VE force feedback interaction system based on haptic handle

基于力触觉手柄的虚拟环境(VE)力反馈系统在人机交互领域得到广泛应用,稳定性是系统正常工作的前提。首先将力反馈设备、虚拟交互环境以及操作者作为独立模块单独建模,再基于阻抗再现方法建立力反馈交互系统闭环控制模型,并利用赫尔维兹判据推导了系统稳定的条件,利用频率响应函数分析了刚度和阻尼、零阶保持器的信号保持时间间隔以及操作者阻抗对系统稳定性的影响,给出了虚拟刚度、虚拟阻尼以及操作者阻抗等影响因素的临界稳定条件。利用研制的力反馈触觉手柄构建了实验系统并进行了实验研究,针对不同的力反馈频率和不同的阻抗分析了不同条件下的系统稳定性。实验结果证明了理论分析的正确性。

VE(virtual environment)force feedback system based on haptic handle has been widely used in human-machine interaction field.Stability is the prerequisite for the system to work properly.Firstly,the force feedback device,the virtual interaction environment and operator are modeled independently as independent modules,then the closed-loop control model of the force feedback interaction system is modeled based on impedance reconstruction method.The Hurwitz criterion is used to derive the system stability conditions,the frequency response function is used to analyze the influences of the stiffness and damping of virtual environment,the signal hold time interval of the zero-order holder and the impedance of the operator on the system stability,and the critical stability conditions of the influence factors,such as virtual stiffness,virtual damping,operator impedance and etc.are given.The developed force feedback haptic handle is utilized to construct an experiment system and experiment study is conducted.The system stability under different conditions is analyzed for different frequencies of force feedback and different virtual environment impedance.The experiment results prove the correctness of the theoretical analysis.