Research On Attitude Control Of Shipborne Parallel Stabilized Platform

As an emerging communication technology,quantum communication system is safer and more reliable than traditional communication technology,but it has higher requirements for the working environment,especially the quantum communication equipment installed on the ship has extremely demanding requirements on the roll and pitch directions.Therefore,it is necessary to use a ship-borne parallel stable platform to isolate the interference of the hull swing,and to ensure that the quantum communication equipment placed on the stable platform is in a stable working environment.The thesis focuses on the attitude control of the ship-borne parallel stabilized platform.In view of the factors affecting the high-precision attitude control of the ship-borne parallel stabilized platform,the research goal of the stabilized platform is proposed.Three electric cylinders are used to form equilateral triangles for distributed support and fixed rod central support to achieve stable platform movement in the rolling and pitching directions.The working principle of the high-precision control system of the stable platform is described.The posture kinematics model is established to eliminate the coupling between the posture angles of each axis.The BP neural network and the Newton-Raphson iterative hybrid algorithm are used to calculate the attitude angle of each axis of the stable platform,and the accurate judgment of the initial relative attitude of the stable platform is realized.The Kane method is used to build the dynamic model of the stable platform to determine the reasonable selection range of the electric cylinder load during the movement,to ensure the high load-bearing performance of the stable platform.The smooth motion planning algorithm is used to avoid the damage of the quantum communication equipment caused by the impact of the stable platform motion.In response to the high-precision and stable performance requirements of the stable platform in the roll and pitch directions,a double closed-loop control strategy is proposed.The PID controller + second-order low-pass filter is used as the feedback controller of the electric cylinder to improve the bandwidth and stability of the electric cylinder position control system,and realize the high-precision following performance of the electric cylinder.The PI controller is used as the attitude feedback controller of each axis to provide a certain attitude feedback strength,and eliminate the steady-state error of the attitude control system,and ensure the high-precision attitude stability of the stable platform.A stable platform experimental prototype was built,and the following performance test of the electric cylinder was tested.The test results showed that the sinusoidal signal response curve of the electric cylinder has no obvious jitter phenomenon,and the position following is stable,which has a good following effect.The attitude stability test of the stable platform on the rocking platform and the ship has been completed.According to the analysis of the test results,the maximum stability error of the platform tested on the rocking platform is 0.53 degree,and the maximum stability error of the platform tested on the ship is 0.56 degree,which shows that The stable platform has high attitude stability performance.