Robust Output Feedback Tracking Control for Inertially Stabilized Platforms With Matched and Unmatched Uncertainties

The use of an inertially stabilized platform (ISP) as a key component in electro-optical tracking instruments to control the sensor's line of sight (LOS) has been investigated for over decades. Its aim is to achieve an accurate tracking for a target and isolate the LOS from the carrier vibrations. A typical assumption in such a system is that the mass distribution of the ISP is symmetrical with respect to the frame axes under consideration. This assumption is rarely satisfied in practice. This paper explores the development of an output feedback controller for an ISP while considering dynamic mass unbalance , where the controller derivation is based on the assumption that all parameters used in the system modeling are unknown , but bounded in size. This assumption implies that the ISP is affected by both matched and unmatched uncertainties. The research, in this paper, illustrates how an indirect robust control can be incorporated with a modified extended state observer-based feedforward term to achieve a high performance on the tracking in the presence of uncertainties, mass imbalance, kinematic coupling, carrier vibrations, and external disturbances. Simulation results are presented to confirm the effectiveness of the proposed scheme.