Study On Optical Axis Stability Technology Of Airborne Photoelectric Platform Under Broadband Vibration Condition

Airborne photoelectric stabilized platform is mainly used for bearing high precision imaging system and is to isolate external disturbance to insure the stability of the visual axis within the inertial space.Therefore,airborne photoelectric stabilized platform has been widely applied in many fields such as modern information,weapons,detection.However,the present airborne photoelectric stabilized platform control systems mostly adopt three-closed-loop control mode related to current feedback,velocity feedback and position feedback.Under the control mode,the platform can't directly restrain the disturbance moment to the platform at root,which seriously affects the visual axis stability capability of photoelectric stabilized platform,thus leading to biases during the process of target tracing and positioning.In view of the above problems,the subject put forward acceleration feedback and feedforward compensation of mass unbalance moment,which can directly restrain disturbance moment in traditional platform control system,to improve the disturbance restrain capacity of the photoelectric stabilized platform,and further to improve the visual axis stability precision of the platform.In the process of establishing an acceleration feedback optimal control tracking differentiator with switch zone linear zone width is designed to add to get the angular acceleration signal of the platform,which greatly reduces noise problems;At the same time,compared with angular acceleration sensor,the cost of obtaining acceleration signal is greatly reduced by using tracking differentiator.Meanwhile,new controller based on pseudo-derivative control strategy is designed to replace traditional PI control strategy,which can reduce the system interference from zeros and improve the system stability.In the process of achieving the feedforward compensation of mass unbalance moment,coordinate transformation relation is established in platform frameworks in accordance with shaft coupling relationship of the platform.The linear acceleration signal after coordinate transformation is used to establish the compensation function of the platform model,to achieve accurate compensation of unbalanced moment.In order to validate the proposed scheme,experiments will be applied to make the platform in swing machine and vibration table to simulate the actual aircraft movements environment,and to verificate the reliability of new control system through the high and low temperatures experiment.New platform system is validated to have good restrain capacity in high frequency and low frequency,thus improving platform disturbance isolation and improving the optical axis stability.