Research On Optoelectric Interference Pod Compound Axis Control

With the continuous updating of modern war photoelectric tracking equipment,higher requirements have been put forward to the photoelectric tracking laser weapon and the ability of photoelectric interference.The key to improve the countermeasure ability of photoelectric interference pod is to improve the light of sight(LOS)pointing precision,this paper study on photoelectric pod decoupling principle,six degree of freedom compound axis control method and target prediction algorithm.The concrete work is as follows:(1)Photoelectric pod decoupling principleDue to the complex structure of the two axis and four gimbal photoelectric interference pod,the multi-gimbals cascade movement makes the linkage between the gimbals affected by the nonlinear coupling of geometric constraint and friction force.The independent control of each gimbal is realized by Euler coordinate transformation decoupling.(2)Compound axis control methodDue to the inner gimbal angle scope is small,the traditional step method is unable to obtain accurate object model.We employ inertial weight decreasing particle swarm optimization(pso)algorithm in this paper,which can identify accurate inner gimbal transfer function model.Outer gimbal resistance wind is effect and it only has able to move follow inner gimbal,so the outer gimbal servo control system hasn't need to high tracking precision performance,consequently,outer gimbal frequency method is used to obtain object model.On the basis of accurate object model,detail implementation process of two axis and four gimbal pitch-pitch structure control algorithm is given in this paper.Its inner gimbal position loop apply to variable structure control method by quadratic curve time sub-optimal algorithm transition from BANG-BANG control section to linear control section.Outer gimbal position loop employ ITAE optimal control algorithm,which realize the minimum weighted time tracking error index.Meanwhile,we put forward to dead zone nonlinear suppression positioning limit cycle in order to suppress outer gimbal jetter.To reduce the uncertainty of object model and equivalent interference,the active disturbance rejection(ADRC)control algorithm is used in fast steering mirror(FSM)position loop,guiding image miss-distance improve the laser light path pointing accuracy through FSM system.Experimental results show that on the basis of two axis and four gimbal composite structure adding FSM system constitute six degrees of freedom compound axis control system which can solve contradiction between system response and high tracking precision.(3)Target prediction algorithmTo improve anti-jamming ability of photoelectric pod and to avoid influence from obstacles,decoy and highlight false targets tracking long-distance target,CA model,CV model and Kalman filtering prediction model is given.Finally,to contrast analysis between model predict and real-time radar data shows that the predicted time of Kalman filter model is superior to the traditional CA model and CV model,which improves the optoelectric pod anti-interference ability.Finally,building optoelectric pod physical platform tests step response and tracking performance of optoelectric pod compound axis control system,the test results show that new type photoelectric interference pod fully meets project requirments.