Output Feedback Synthesis for a Two-Agent Nonlinear Microrobotic System
Abstract
Most of minimally invasive therapeutic applications demand to control multiple microrobots. If such microrobots are actuated by a magnetic device whose magnetic field is stationary, like magnetic resonance imaging devices, there is only a single control input per axis so the system is underactuated. Besides, imaging provides only a poor information about the robots state. That is the reason why it is necessary to synthesize observers to rebuild enough information to enable the stabilization of the two-agent system along a reference trajectory. This work addresses the observability and output feedback synthesis for two microrobots facing the blood flow. We propose two observers syntheses depending on the available output of the system: a Luenberger observer if the imaging provides the position of each robot, and a high gain observer if magnetic artifacts only allow for a measurement of a single linear combination of the robots positions. The output feedback is then designed using an exact feedback linearization approach. Simulations illustrate the efficiency of the proposed approach for both observers.
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