An improvement project of LAMOST will be implemented soon. To improve the observation accuracy and spectral acquisition rate, a new integrated fiber positioner was designed for the new robotic Focal Plane System. This paper designs the drive system for the integrated fiber positioner, and introduces the mechanical, electronic and software design in detail. We also built a vision measurement platform with a telecentric lenses to test the position performance. The fiber positioner positions the fiber to target by first blind positioning and multiple position corrections. After the positioner completes the first blind move, the camera takes the fiber image and calculates the offset between the actual position of the fiber from its target position. Then, the drive system controls the fiber positioner move according the offset value to correct the fiber position. We achieve the final accuracy through iterative position corrections. Experimental results show that both the drive system and the fiber positioner have reliable performance and high efficiency. With a first blind move inside of its workspace, the positioner can position the fibers with a planar precision better than 100um, the position error is less than 10um after the second correction and the RMS error is less than 3um.

The multiobject fiber-fed spectrograph is the core scientific instrument for large-scale spectroscopic surveys. For closed-loop control of fiber positioning, fiber metrology systems are implemented in numerous fiber-fed spectrographs. The position accuracy of the fiducial fiber in the focal plate directly affects the performance of the fiber metrology system. However, there are currently no suitable methods and devices for measuring the fiducial fibers with high accuracy in the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). To solve this problem, this study proposed a novel online scanning measurement method for fiducial fibers in which a scanning camera was set up in front of the focal plate, and the rotation and translation movements of the focal plate were combined to set a polar coordinate measurement system. First, the pole and polar axis of the polar coordinate frame were determined, and the compensation values of the polar radius and angle of the polar coordinate of the fiducial fibers were solved in the field of view of the scanning camera. A prototype measurement platform was set up to verify the feasibility and scientific validity of the method. Experiment results show that the polar radius accuracy of the proposed method met the measurement requirements. The X–Y measurement accuracy can be further improved when a higher-precision rotary stage is adopted. Thus, the difficulties in online accurate measurement for fiducial fibers can be tackled by the proposed method with good operability in LAMOST.