Research On Large-scale Fast-steering-mirror Driven By Voice Coil Motor And Its Line-of-sight Stabilization Technology

As an important mode of reconnaissance in modern war,the Reconnaissance distance of aviation photoelectric reconnaissance platform directly determines the efficiency of reconnaissance and its own security.Therefore,the reflective telephoto camera with a longer imaging distance is applied to the field of aerial reconnaissance.At the same time,as the focal length of the camera increases,the requirements for the stabilization accuracy of line-of-sight are also higher and the traditional frame servo stabilization system cann't support the telephoto camera to work properly.The secondary line-of-sight stabilization system based on FSM(fast steering mirror)can greatly improve the stabilization precision of line-of-sight.However,the stability of the line-of-sight requires a large stroke of the FSM,and the harsh aviation environment will affect the performance of the FSM.Therefore,researching a FSM with large scale,high performance and strong anti-disturbance ability is of great significance for improving aviation reconnaissance efficiency.The FSM driven by voice coil motor can satisfy the requirements of the platform for angle range,but it is very susceptible to external disturbances.In addition,compared with the piezoelectric ceramics,the voice coil motor is more difficult to control and the bandwidth is difficult to upgrade.In view of the above problems,this paper has carried out detailed research on the self-developed FSM and improved its response speed and robustness through control algorithm.And apply this self-developed FSM to the airborne optoelectronic platform to test its effect on the accuracy of the line-of-sight.The main research contents of this paper are summarized as follows:The theoretical model of the FSM is derived based on the kinematics theory.A method of constructing white noise in time domain by sinusoidal superposition is proposed,and this method is used to model the FSM.The speed negative feedback compensation is used to improve the damping coefficient of the system to suppress the second-order model resonance.In order to restrain the resonance peak and antiresonance peak caused by mechanical resonance,a novel structure filter on the grounds of double T-type notch filter is proposed.The relationship between the response speed and the control bandwidth is analyzed.The theoretical derivation results show that the higher the system control bandwidth,the faster the system response speed.According to the open-loop model,the PI controller is designed to the position loop of the FSM.Then the same modeling method is used to identify the closed-loop system.Based on these,ZPETC(zero phase error tracking control method)is proposed to further improve the control bandwidth.Experimental results show that after adding ZPETC,the system-3dB bandwidth reaches 550 Hz.The disturbances affecting the control system of FSM in the aviation environment are analyzed one by one,and the equivalent disturbance is used to approximate all the external disturbances,which simplifies the design of the anti-disturbance algorithm.In the control system of FSM,two kinds of anti-disturbance methods,DOB(disturbance observer)and ARC(adaptive robust control),are tested respectively.The robustness of the two algorithms and their improvement of the anti-disturbance ability are compared,and the disadvantage of the two algorithm are analyzed.Experiments were carried out on the vibration table to test the anti-disturbance effects of the two algorithms.The experimental results show that the ARC improves the system's anti-disturbance ability by 4.83 times,which is much higher than the DOB's 1.9 times.The structure and load of the airborne optoelectronic platform are introduced.The principle of the line-of-sight stability and the factors that limit the further improvement of the line-of-sight stability are analyzed.A two-stage line-of-sight stabilization system based on FSM is proposed,and the disturbance isolation of the two stabilization system are compared and analyzed.The five-axis swing table was used to simulate the aviation environment,and the actual performance of the two line-of-sight stabilization methods was tested.An image processing method is proposed to calculate the line-of-sight stability accuracy.The experimental results show that the stable accuracy of the onestage stable mode is 20.3 urad,and the stable accuracy of the two-stage stable mode is 5.1 urad.Based on the research work of this paper,the rapidity and robustness of the FSM driven by voice coil motor are greatly improved after introducing the ZPETC controller and the ARC controller,which satisfies the performance requirements of the airborne optoelectronic platform for FSM.After the FSM is added to the imaging optical path,the stability of the line-of-sight is greatly improved,which is enough to ensure the proper functioning of the camera with a focal length of about 1m.