Research On Four-channel Piezoelectric Actuator And Its Control Strategy For Spinning Projectile

As the main component of intelligent missile,the performance of the rudder actuator greatly influences the guidance effect of the projectile.At present,electromagnetic motor is widely used in the design and research of smart missile due to its stability and maturity.However,the magnetic field generated by electromagnetic motor itself will interfere with the electromagnetic sensor.And it also has some disadvantages such as low precision,narrow bandwidth,large volume and weight.Besides,the integrated design of the motor will has huge challenge especially when it is used in high-spin guided projectile.The intelligent structure made of piezoelectric material has many advantages such as large control bandwidth,fast response speed,simple structure and flexible design,which is very suitable for the design of actuator used in the modern smart missile.In this paper,the output and control characteristics of the piezoelectric beam used in the post buckled pre-compressed(PBP)actuator are analyzed.Then a four-channel piezoelectric actuator for 2D trajectory correction of high-spin projectiles is proposed.Based on the application of the actuator in the spinnig stabilized missile,the motion equation of the projectile is established,and the guidance effect under the control strategy is studied.The main contents of the paper are summarized as follows:(1)The dynamic models of piezoelectric beams under complex boundary conditions are established,Obtaining the static and dynamic output characteristics.The accuracy of the dynamic models are verified through simulations and experiments.The results show that the increase of axial force will significantly improve the electromechanical conversion efficiency of the piezoelectric beams under two different boundary conditions.Besides,the force and displacement outputs are amplified,and the natural frequency is reduced.The increase of axial force has little effect on the transient characteristics of the bimorph,and its response time is still in milliseconds under a large axial force.(2)The rigid-flexible coupling dynamics model of the post-buckled pre-compressed(PBP)actuator is established,and its output characteristics in different complex environments are studied.Therefore,a fuzzy controller with online parameter tuning function is designed.The results show that the introduction of the controller not only makes the PBP actuator have a faster response speed and a smaller overshoot for both continuous and discontinuous signals,but also improves its anti-interference ability,thus ensuring the good robustness of the system.(3)A four-channel piezoelectric actuator structure,based on the PBP driving method for spinning stabilized smart missile is proposed,and its correction and control principle are described.The aerodynamic characteristics of the projectile are obtained by using the CFD software,and the rotational speed control effect of the rotator is studied by simulations and experiments.It can be concluded that the four-channel piezoelectric actuator has good speed control ability,which can meet the application requirements of trajectory correction of spinning guided missile.(4)Based on the application of the four-channel piezoelectric actuator on the rocket projectile,the flight dynamics model of the missile is established.This model not only describes the six degrees of freedom of projectile movement,but also considers the rotations of rudders and rotor.The trajectory characteristics under open-loop control are obtained by numerical simulation,and the guidance capability of PBP guided rocket projectile is evaluated.As a result,the correction ability of the projectile is slightly larger in the lateral direction than that in the longitudinal direction,and the maximum correction radius is about 600 m.(5)The control principle of the PBP spinning guided projectile is analyzed,and the implementation of the two correction laws(trajectory tracking and impact point prediction)on this missile are given.Numerical methods are used to study the flight characteristics of projectiles under different correction laws,and Monte Carlo simulations are built to obtain the distribution of falling locations.It can be seen that the precision attack ability of the projectile to the target is improved under the two correction laws while the initial muzzle disturbance exists.The striking point concentration of projectiles under the IPP correction law is obviously better than that under the TT correction law.In addition,the projectile still has a good guidance effect under the IPP correction under the wind interference.A four-channel piezoelectric actuator for high-spin projectiles is proposed in this paper,and two trajectory correction laws are used to evaluate the guidance effect of the missile.The results show that the actuator can provide stable correction force for projectiles,and its response speed and output capacity can meet the application requirements of high spin guided missiles.This research provides a key technology for the design of low-cost intelligent missile.