Design of rotation control system based on four-gimbal platform

The technology of rotation modulation is applied on four-gimbal platform can improve the accuracy system and overcome the shortages of the strapdown system which cannot isolate the carrier angle motion. In this paper, a new design method of dual-axis rotation control system on four-gimbal platform is proposed. The performance index is demonstrated by analysis the influence of the rotation control error on the rotation modulation system. The proposed design method including distribution of the control signals, calculate the rotation command angular velocity. The rotation controller is designed, the function of locking gimbal, isolated angle motion and platform rotation are implemented. Experimental results from a real dual-axis rotation system demonstrate that the step response settling time is less than 0.2s and dynamic error is less than 300 arc sec in the moment of reverse. The results show that overall performance of the control system can satisfying the demands of the inertial navigation system.