A new type of R- θ optical fiber positioning robot based on double composite parallelogram mechanism

Fiber positioners are essential for contemporary multi-object spectroscopic facilities as fiber positioner arrays can simultaneously place thousands of fibers. Reducing the pitch between fiber positioners increases the number of positioners at the focal plate, improving the efficiency of sky surveys. However, the collision probabilities between positioners will also increase, making path planning challenge. To solve this problem, a new R- θ fiber positioner with the double composite parallelogram mechanism is proposed It adopts the micro displacement system containing a piezoelectric ceramic actuator and a flexible hinge mechanism. To guarantee the precise linear movement of R mechanism, a parameterized virtual prototype of the robot is constructed and optimized. Finally, the performance of the manufactured R mechanism is verified by experiment. Results show that the newly designed R- θ fiber positioner can meet the requirements of accuracy.