Research On Shipborne Laser Communication Optical Stability Control Technology

The optical axis stability control technology is the key technology of laser communication system,which aims to achieve the high precision alignment of the transceiver link between the laser communication terminal machines in a long time,and it is the prediction of laser communication system.However,the shipborne laser communication system is affected by the six degrees of freedom attitude disturbance caused by wave sway and ship motion and system internal nonlinear disturbance under the complex sea conditions,therefore the laser optical axis cannot be stabilized at the target surface of the target terminal detector,which results in the failure of the laser communication technology.In order to overcome the dual requirements of the complex sea condition environment and the high precision optical axis alignment,the traditional control strategy can no longer meet the design needs of the laser communication control system,so it is necessary to study the effective modern control method to establish the laser communication optical axis stability control system to achieve the high precision optical axis control.This paper conducts research and analysis from the following four aspects to improve the alignment accuracy of laser optical axis:Firstly,the research of high precision servo turntable control technology,which is the basis and guarantee for achieving high precision tracking control of optical axis.The servo turntable controller adopts the design idea of modern control,the nonlinear disturbance such as torque unevenness,friction,system parameter perturbation and so on are unified as nonlinear factors for theoretical research,and the robust sliding mode control algorithm is designed to suppress nonlinear factors to ensure the high precision control of the servo turntable.Secondly,the research of the waves and the ship motion attitude disturbance feedforward compensation technology,this technology is the first-order isolation technology for attitude disturbance.In this paper,the influence of the ship’s yaw,roll and pitch caused by waves and the ship’s forward motion,lateral drift and undulating motion on the stability of the optical axis is analyzed respectively,and Euler Angle calculating method is adopt to establish the attitude transfer matrix and six degrees of freedom attitude disturbance optical axis model can be deduced by data decoupling calculated,finally,the primary stabilization of the optical axis is realized by the velocity compensation control of feedforward.Thirdly,the research of the high precision optical axis stability control technology,this technology is the second-order isolation technology for attitude disturbance,which is also the laser communication control system coarse tracking control technology.Essentially,this technology is the position loop control technology,the fusion data of image deviation and turntable position as the information Source,the high-precision controller controls the target facula always at the center of the detector target surface to achieve high precision alignment of the laser optical axis.Fourthly,the research of the deviation data time-delay compensation technology.Due to the detector photoelectric conversion time,the image deviation data lags encoder data,and this time-delay problem can reduce control system accuracy and stability of the optical axis.therefore,based on the target facula motion model and adaptive Kalman prediction filtering algorithm,a coaxial tracking control technology is established in this paper,which can effectively estimate the lag deviation data,further improving the accuracy of optical axis alignment and the stability of the system.In this paper,the high precision turntable servo control experiment,the equivalent shipborne environment optical axis primary stability experiment,and high precision optical axis stability control experiment are carried out respectively,the experimental results show that the control strategy can effectively isolate the waves attitude disturbance and system internal nonlinear disturbance effect of optical axis,fully meet the requirements of laser communication optical axis alignment precision index,provide strong support for subsequent laser communication technology research and practice.Meanwhile,the experimental results further verify the effectiveness of the novel chatter-free sliding mode control algorithm,novel fast approvement chatter-free sliding mode control algorithm,optical axis attitude disturbance model and adaptive Kalman filtering algorithm.