Abstract: A type of three-axis photoelectric tracking system with a redundant degree of freedom is designed for avoiding the spatial blind region of two-axis photoelectric tracking system and realizing the tracking movement in whole space. Based on the movement analysis of three-axis photoelectric tracking system, the kinematical model of system with redundant degree of freedom is built by using quaternion method. Then, adaptive differential evolution (ADE) algorithm is designed for the tracking strategy of three-axis tracking system. Through the analysis of the kinematical model, the relationship between three axes rotating angles could be obtained. Then three-variable optimization of three axes angular increments could be simplified as the optimization of single-variable, and the optimal three-axis angular increments are calculated by using ADE. The results of simulation and experiment show that this tracking strategy can realize three-axis linkage continuous tracking movement in whole space, which could avoid the switch course between different axes in the tracking process, and this tracking strategy could track the target with smaller three axes angular increments. Therefore the tracking performance of this tracking strategy is more superior to other tracking strategies, and it has great value in engineering application.

Key words: Adaptive differential evolution(ADE), Optimization, Tracking performance, Tracking system, Three axes