A New Miniaturized Fiber Positioning Node Based On Zigbee

The fiber positioning system is one of the most important parts of LAMOST(The Large Sky Area Multi-Object Fiber Spectroscopic Telescope),which consists of 4,000 fiber positioning nodes and each of them can position a fiber.In addition,all of the fiber positioning nodes are distributed on the focal plate of 1.75m in diameter.As the self-innovation and key technology of LAMOST,the fiber positioning system has been working steadily for more than 8 years.At present,a higher demand to install at least 4,000 fiber positioning nodes on focal plate of 1.75m in diameter is put forward and the most effective solution is to miniaturize the fiber positioning nodes.Every fiber positioning node consists of three parts:the wireless driving system,the mechanical device and the two stepper motors.The size of stepper motor has reduced from 10mm to 6mm in diameter,but the size of mechanical device depends on the wireless drive system.Therefore,to miniaturize the wireless driving system is of great importance and difficulties as well.The previous is 100 mm long and 15 mm wide and consists of the minimum system of wireless SOC based on technology of ZigBee wireless communication and the stepper motor driver module.In order to miniaturize the wireless driving system,two steps a wireless driving system board re proposed in the paper.The first step is to adopt a smaller-size wireless SOC to replace the original one.The CC2530 used on new board is 6mm long and 6mm wide as a true system-on-chip solution for IEEE 802.15.4 and ZigBee applications launched by TI.The previous MC13213,with the size of 9mm x 9mm,possesses less performance of MCU and peripherals.The second step is to redesign the wireless driving system board including smaller-size components and layout in order to achieve the best communication performance.As a result,the size of the new wireless driving system reduces by above 40%.Meanwhile,the entire structure of every fiber positioning node can be designed smaller.