多通道测力仪动态信号反向滤波补偿方法
Multi？？Channel Dynamic Force Measurement and Compensation with Inverse Filter

为了消除动态测力仪的结构动态特性对测试结果的干扰,采用反向滤波的方法对动态力测试信号进行修正。根据最小相位系统理论设计反向数字滤波器,由单输入单输出反向数字滤波器的设计原理,提出了多输入多输出反向数字滤波器的设计方法。根据测力系统激励力与测试值之间的频响函数矩阵,建立测力系统传递函数模型,并进行最小相位转化,将最小相位动态力传递函数模型反转,得到反向滤波器。实验结果表明:经过反向滤波处理的动态力测试值与实际动态力具有相同的幅值;运用零相位滤波方法,消除了测试信号与实际动态力之间的相位差;测试结果与动态力实际输入幅值误差小于6％。
To eliminate the influence of structural dynamics of dynamometer on measurement accuracy of dynamic force, an inverse filter method is considered to modify dynamic signals of the measurement system. Following the theory of the minimum？？phase system, an inverse filter with multi？？input and multi？？output is designed, and an inverse filter matrix is established to compensate the cross？？interference between dynamic forces in different directions. The frequency response matrix of the excitation force and measured one is used to model the system dynamics and to transfer into a minimum？？phase system. Inverting the minimum？？phase transfer function matrix, the inverse filter matrix is obtained. The simulation and experiment show that the magnitude of the measured dynamic force matches well with that of the actual dynamic force. Zero？？phase filtering effectively eliminates the phase delay and the relative errors are controlled within 6％