Research On Airship Load Vibration Isolation System Based On Characteristic Model Theory

Vibration isolation is a basic problem to improve the quality of images taken by camera.There are many solutions to solve this problem,such as digital blur reduction based on image processing algorithm,CCD and optical image stabilization,and three axis gimbal based on mechanical system.For the airship load,that is,when the airship is equipped with cameras and other equipment,we needs to isolate vibralion also.There is no denying that the three axis gimbal system does not have the ability to isolate vibration in vertical direction.Based on this,we design a vibration isolation equipment integrating the active and passive vibration isolators and the three axis platform system,which adds a degree of freedom in vertical direction for the three-axis platform,and at the same time,it can meet the stability and high-precision task index of the vibration isolation system,The full coefficient intelligent adaptive control algorithm based on feature model is designed and verified accordingly.Based on this,this paper has carried out a series of work as follows.(1)The three axis platform system needs to have two functions of attitude control and vibration isolation.Attitude detection can be obtained by accelerometer,gyroscope,magnetometer and other sensors,obtained by complementary filtering.The executive motor adopts three-phase(Brushless Direct Current Machine)BLDCM,which is driven by field oriented control method.This paper presents the characteristic modeling of the three axis platform system,and establishes the mathematical model of the three-phase BLDCM.We alalyzed the load disturbance of the three motors of the three-axis gimbal system.According to the control requirements of the three axis gimbal,We use PI control method in the current loop to realize the stable and good follow-up characteristics of the current loop.The results of this characteristic are difficult to analyze in the engineering.The three-phase electric motor based on(Space Vector Pluse Width Modulation)SVPWM algorithm is difficult to analyze The current output is a sine wave with a phase difference of 120 ° and a decoupling method is proposed to analyze and evaluate the following performance of the current loop.The full coefficient intelligent adaptive controller is designed to meet the stability and anti-interference capability of position control,and finally realize the vibration isolation function of the three axis platform.(2)In view of the vibration isolation in vertical direction,this paper establishes a vibration isolation system which combines active and passive vibration isolation.The high frequency vibration signal is isolated by rubber material,the low frequency vibration signal is isolated by active vibration isolator,the actuator of active vibration isolator uses Voice Coil Motor(VCM),and the control model of VCM is established according to the control performance requirements.The hysteresis of the system is affected by PI controller to realize the good follow-up of current.In order to improve the accuracy and anti-interference capability of position control,a full coefficient intelligent adaptive control law is designed to control the position of the motor in closed loop.The experimental results show the relationship between the vibration isolation performance and the vibration source frequency of the voice coil motor,which proves that the active isolator has a significant inhibition effect on low frequency vibration.