Decoupling Algorithm and Maximum Operation Frequency of a Novel Parallel Type Six-Axis Accelerometer

This paper presents a novel non-gyro six-axis accelerometer based on a derivative of Stewart parallel mechanism (SPM). To reduce the impact of interference noise, a set of geometric constraint equations are presented to compensate the errors of redundant outputs. A decoupling algorithm is introduced for easy modelling of this multiple-axis vibration problem. An auxiliary angular velocity is adopted so that the system dynamic equations can be directly solved by traditional explicit recursive formulas (ERFs) for real-time applications. Both an eigenvalue analytical algorithm and a matrix iteration approach are used to compute the fundamental frequency (FF) of the accelerometer for comparison. At the end, a four-step method is summarized in order to obtain an appropriate operation frequency range of this sensor. The analysis results reveal that the maximum operation frequency (MOF) of a parallel type six-axis accelerometer is always proportional to its FF in a ratio between 1/35~1/32. The predicted numerical results of the established decoupling algorithm are verified within the identified operation frequency bandwidth by comparing with virtual and actual experiment data, showing a maximum relative error of 0.47% and 8.87%, respectively.