Focusing mechanism is an essential part of large-scale photoelectric tracking device and zoom lens

performance of whole tracking control system is directly determined by focusing precision. At present

most focusing mechanisms adopt grating ruler as acquisition of displacement and feedback unit to realize closed-loop control of system

their major shortages are bulky size and poor temperature adaptability which can not meet requirement of high temperature working environment. Design a wide temperature focusing mechanism including an inductive linear displacement sensor

a DSP & FPGA focusing control card

a stepper motor

and an electric displacement platform. System architecture

hardware implementation and software flow are introduced in detail

systematic parameters analysis and experimental results indicate that this design can satisfy requirements.