Quantitative Analysis Method of Error Sources in Magnetohydrodynamic Angular Rate Sensor for Structure Optimization

A comprehensive study on the error analysis of magnetohydrodynamic (MHD) angular rate sensor (ARS) is essential for structure optimization to reduce its tracking error and expand the bandwidth at low frequency. Against the error sources in the MHD ARS, secondary flow, and induced magnetic field, this paper presents a quantitative analysis method to study the optimization of structural parameters. Stream function is introduced to help giving analysis of secondary flow. Two models with and without induced magnetic field are utilized for comparison to illustrate its influence. Error sources varying with time and frequency are simulated. Experiments of MHD ARS on frequency response functions and linearity are made to verify the effectiveness of the error analysis method. Furthermore, the optimization design of MHD ARS structural parameters is discussed. According to the simulation and experiment results, the impact of unsteady secondary flow is relatively strong in low-frequency band but not significant above 2 Hz and tends to be weakened by the imposed magnetic field. The deviation caused by the induced magnetic field is less than 0.1% when the rotation is less than 100 rad/s. Among the parameters for structural optimization, the aspect ratio should be designed as large as possible in the premise of small magnetic Reynolds number.