Dynamic compensation method based on system identification and error-overrun mode correction for strain force sensor

Abstract

To improve the dynamic performance of strain force sensor, a new dynamic compensation method based on system identification and error-overrun (EOV) mode correction is proposed to solve the problem that the existing methods though can improve the time-domain tracking performance but sometimes fail to widen the frequency-domain measurement bandwidth of the sensor simultaneously. For the new method, sensor dynamic compensation is divided into primary and secondary compensations. Primary compensator is obtained by system identification method for correcting the overall frequency response of the sensor, secondary compensators are constructed in a unified structure of 2nd-order system for purposely correcting the remaining EOV modes that limit the sensor measurement bandwidth. Specifically, construction methods of four categories of secondary compensators are discussed; circular construction of multiple secondary compensators and sequential dynamic compensation of sensor output are presented; last, an ATI Mini45 force/torque sensor is employed for verification. The results show that, the proposed method can shorten the step adjust times of the sensor six channels from up to hundreds of millisecond to within 3 ms and widen the bandwidths from around 30 Hz to over 100 Hz; and that, re-identifying a wideband primary compensator and constructing more secondary compensators can further improve the former indices to 0.45 ms and over 287 Hz for a channel. Consequently, the proposed method can effectively improve the time-domain tracking performance and measurement bandwidth of the sensor simultaneously, and it is proven to be effective, practical, and robust for sensor dynamic compensation.