Abstract: Submarine-based electro-optical tracking and pointing systems are always disturbed by the external flow field, which makes the vibrations with different frequencies and amplitudes generated from the interaction between the fluid and submarine. The strem-induced noise of the electro-optical tracking and pointing system is suppressed by controlling the boundary layer of wall electromagnetic fluid, and the control effect of energy accumulation is evaluated by using the wall Lorentz force. The hydrodynamic characteristics of submarine under or without the action of streamwise Lorentz force at Re=10⁷, a 6° yaw angle and a 10° pitch angle are numerically analyzed based on the finite volume method. The transfer functions of the direct current torque motor ( DTM ) and fast steering mirror ( FSM ) were deduced and simulated to evaluate the control effect of Lorentz force on the output error of the composite axis tracking system. The torque disturbance of submarine is transformed from the earth coordinate system to the optical axis coordinate system, which is used as the disturbance inputs of the tracking and pointing system in MATLAB Simulink to simulate and analyze the final control precision for azimuth/pitch angles. The results show that the Lorentz control method can be used to effectively alter the flow field structure on the submarine wall surface, suppress the high-frequency disturbance vortexes and enhance the laser directed energy density on a target.

Key words: directedenergysystem, trackingandpointing, turbulencepulsation, compositeaxistrackingandpointingsystem, Lorentzforcefilter