Study Of Pointing, Acquiring And Tracking Servo Control System Based On TMS320LF2407ADSP

In space laser communication, the system for pointing, acquisition, and tracking (PAT) plays a critical role for establishing the communication access between moving communication terminals. In the traditional PAT system, its large volume and long acquisition time restrict the development of the space laser communication. Thus, it is very valuable to miniaturize the PAT system servo controller and optimize the scanning algorithm.The paper gives a viable space laser communication PAT system ground model and implements a subminiature PAT servo controller based on TMS320LF2407A DSP, based on the analyzing of the existing space laser communication PAT system. TMS320LF2407A DSP makes up of the core of the servo controller. It implements the operation of the timing and the comparing, the controlling of the speed and position, the communication with the identifying and orientation system of beacon, the communication of the host, and the operation of I/O scanning algorithm. The power driving module, the motors, and the complex axes constitute the performing cell. The optical system, and the identifying and orientation system of beacon compose of the controlled object and the outside feedback signal of the closed loop system separately. The magnetic encoder and signal processing part form the inside feedback signal of the closed loop system. The paper analyzes the structure principle and the characteristic parameter of the control system in detail. In the PWM output function of the control system, it implements the improved digital PID algorithm on two motors with only one chip. At the same time, the parameter of the digital PID controller is discussed in the paper. In the I/O scanning algorithm, it discusses the selection of the radiation angle of the beacon, confirms the step of the raster spire scanning and the beehive spire scanning, implements the algorithm of the raster spire scanning and the beehive spire scanning on chip, and studies the point-ahead technology and the dynamic controlling of the point-ahead scanning parameter. The error analysis of the implementing cell and the experiment result of the scanning mode prove that the miniaturized PAT servo controller is feasible and practical.