Research On Structural Analysis And Control Scheme Of Airborne Polarimetric Microwave Radiometer Servo Device

Microwave radiometer，which is loaded with aerial，transmitter，receiver，power supply， data acquisition system and unit controlling system in theloading-cabin, achieves target information by receiving the microwave radiated bytarget. Fully polarimetric microwave radiometer can scan in the way of two degrees offreedom including horizontal rotation and Pitching rotation. The servo turntable is thecore part of the microwave radiometer. The servo turntable is installed under theopening cabin of aircraft belly so that ground and ocean can be explored easily.Therefore, efficient following characteristic and robust is needed. The performance ofservo turntable，which is the fundamental ensure for microwave radiometer, directlyinfluences the reliability of microwave radiometer.The servo turntable has two degree of freedom. The overall structure of thedevice is divided into four parts, namely, the overall control unit, azimuth servoturntable, elevation servo turntable and frame. The Overall control unit is the FPGA.Servo control system of azimuth and pitching turntable is drived by DC motorconnected by planetary gear reducer. Closed-loop controlling is achieved throughservo drives, encoders and control unit. Servo system consists of the servo controller,the angle (position) sensor, servo motors, antenna drives and the interface to matchcircuit in the host computer onboard. According to the instructions issued by the hostcomputer, system control circuit controls the antenna drive. The host computer timelyachieves feedback operating status data of antenna drive. At the same time the stateindicators meet certain requirements, the system can work reliably under certainconditions.Firstly, a detailed analysis for the structure and motion features of servo device isdone. To understand the structure and motion features is the premise and foundationfor design of the control system. At the same time the servo device structure isanalyzed by finite element method to prove the structure design rational and reliable. It is the establishment of a correct theoretical basis for the subsequent design of thecontrol system.Secondly, on the basis of understanding the structure of the device, the entireservo controller device is designed. The inverse system modeling method, thetraditional PID control and fuzzy adaptive PID control algorithm is mainly and deeplystudied. Meanwhile, the simulation experiment of designed controller is conducted toverify the feasibility of the control strategy. The control strategy has its innovation,which is,on one hand, the control strategy combining inverse system modeling theoryand fuzzy adaptive PID algorithm is verified by simulation analysis, on the other hand,the designed controller is verified by experiment, Namely, using control systemdesigned around DSP and downsized, modeling turntable device, an experiment oflower cost is conducted. Throughout the experiment we test the feasibility of thecontrol scheme and achieve the combination of theory and practice.