The Research On Stabilization Of LOS Of Dynamic-based Electro-optical Theodolite

When Optical-electric equipment is tracking and measuring target on movingbase, the LOS is interfered by external disturbances, such as moving basedisturbance,unbalanced friction torque and unbalance mass of mechanical structureand so on. So that the LOS will deviate from the original direction, even lost thetarget. We should isolate LOS from moving base, overcome the impact ofdisturbance torque on LOS. It is foundation of tracking and measuring that keep theLOS stably direction in inertial space. It is a key technology of the optical trackingsystem on moving base.This paper analyzes the structure of the LOS stabilization system, studies thecharacteristics of the main components, analyzes mathematical model of torquemotor and load, gyro, image processors and other parts associated to servo controlsystem. So establish mathematical model of entire system. The paper establish LOSisolation equations by coordinate transformation, according to the structure of theLOS stabilization system and position of gyro.The paper introduces double speed loop in the speed loop of LOS stabilization.The inner speed loop is formed by the speed of LOS in the inertial space by gyro. Itis used for eliminating carrier disturbance and friction torque disturbance, achievingthe LOS stability. The outer speed loop is formed by the encoder, it is used for measuring the speed of the theodolite frame. The outer loop is used for trackingtarget. The paper Discuss the performance of double speed loops onanti-interference, dynamic response and robustness. It adopts robust control theoryon designing controller to ensure the stability and robustness of the closed-loopcontrol system.The paper designs the position loop of LOS stably control system on movingcarrier. On TV automatic tracking mode, servo control system receives the off-targrtis postponed relative to the true target position. The delay time limits the bandwidthof the position loop in designing servo system, reduces the rapid response of thetracking control system, and impacts the accuracy and stability of the system. Thepaper induces Kalman filtering method in the position filter and prediction, base onmaneuvering target model, and constitutes feedforward control by the filter andprediction position and speed. It improved tracking control accuracy of the system.On the beginning of tracking stage, introduce the variable structure control method,the system can respond quickly and turn to the stable tracking stage quickly.Finally, the theory is verified on some Optical-electric tracking and measuringsystem, placed on a three-dimensional rock platform. Analyze through simulationand experimental results, the methods possess greater advantage on resisting carriermovement and restraining model uncertainties influence to the dynamiccharacteristics of the system. The experimental results demonstrate the effectivenessof this approach.