Application Of DC Servo System In Focus System Based On DSP

When a O-E theodolite tracking and measuring the flying target, the distance between the target and the equipment changes unceasingly, thus cause changes of the image position, and makes the image of target defocus, energy diffuse and decrease of the contrast between target and background, affecting the imaging quality. The motive is adjust the image plane position according to the distance information of target and equipment, making the image locate in the focal plane all the time, thus when using the photography measuring we could capture the more clear image and improve the ability of discovering target, so improve the operating distance.The focus system can be divided into two major parts, one is the optics mechanics, the other is the electricity control part. The latter is realized to drive the objective lens, laid inside the path of rays channel, by motor. The move distance is decided by the voltage signal, which has direct proportion with the distance by output of potentiometer. The electricity control part consists of core controller, motor and the power drive.Contraposing shortages consisted in previous focus control system, such as slow response speed, low precision and etc,the paper introduces double-closed-loop control instead of open-loop control,import speed adjustment to overcome load perturbation and restrain disturbs, improve the response speed of system. Improve the location precision of system by using position adjustment and show the result. On technology, orient-motor-controlled DSP chip TMS320f240 is used instead of Single Chip Micyoco (SCM), which improves the integration degree and the level of control.