Position Self-Correction of Resolver Based on a Composite Method in Gimbal System

This article explores a composite self-correction method for the angular position of the resolver in the gimbal system of the control moment gyroscope (CMG). The nonideal signals of the resolver in the gimbal resolver-to-digital conversion (RDC) system result in a systematic error, which can decrease the performance of the output torque of the CMG. However, it is impractical to adopt additional high-precision sensors to correct the angular position of the resolver in the installed gimbal system on account of the limitation of the structure and space. Therefore, a novel self-correction composite method based on a discrete extended state observer (DESO) and a harmonic observer method (HOM) is put forward to calibrate the angular position of the resolver. First, the sine and cosine signals with harmonics can be directly obtained. Then, the composite proposed method is performed to get the accurate angular position of the resolver, and the position error can also be acquired. Based on the position error, the compensation table can be established, and finally, the high-precision position can be acquired. The proposed self-correction method is verified by simulation and experiments, and the results show that the angular position accuracy is significantly improved.