A robotic focal plane system using robotic fiber positioners enables multi-object spectroscopy for hundreds to thousands of galaxies by utilizing a dense array of positioners that are closely packed at the focal plane of a telescope. While this dense arrangement increases the number of observations, it also introduces the potential for collisions between adjacent positioners. A fiber positioner is designed similarly to a SCARA robot. It is driven by two series of BLDC motors. Each positioner is manufactured with an outer diameter of 16 mm. It operates within an annular workspace with an outer diameter of 33.6 mm and an inner diameter of 12.8 mm. As these positioners are arranged with a spacing of 16.8 mm, target assignment and motion planning are critical to avoid collisions caused by overlapping workspaces. To address this, we proposed an optimized step choice algorithm using a motion planning method based on optimization with the sequential quadratic programming algorithm. Simulation results demonstrated that paths for all positioners within a tile were successfully generated with a success rate of up to 93.75% across 80 tiles.

With the advent of high-tech products, the need for ultra-precision machining has become increasingly necessary, along with the need for a jig center machining center capable of precision machining. A jig center maintains the accuracy of a jig borer, and also has an automatic tool changer like that of a machining center. It performs various machining functions in addition to hole machining and is the most precise and rigid machine tool. Various control methods and analytical techniques to improve machining accuracy are currently being developed in the field of ultra-precise large-scale machine tools. One relevant finding is that the degree of deformation varies depending on the weight of the machine tool as well as the ground conditions. It is therefore necessary to optimize ground conditions before installing the machine tools so as to improve the machining accuracy. The depth of concrete as well as the depth and diameter of grout were selected as variables. We developed the simulation case through structural analysis to consider the position of columns and tables. As a result of optimizing the foundation condition, it was found that the relative displacement error was reduced by up to 98% compared to the rigid foundation condition.

An essential mechanical element in an industrial machine is a reducer, which transfers the rotation of an electrical motor or engine to another part with amplified torque. Some reducers, such as planetary reduction gears, a harmonic reducer, or a cycloid reducer, have been applied in various industries. Given the increase of demand for reducers with high precision, compact size, and high load capacity for use in industrial robots, the cycloid reducer has stood out. The cycloid reducer, compared with planetary reduction gears, has some merits, which include a larger reduction gear ratio at only one stage, higher durability, improved efficiency, and a larger torque because of its high tooth-contact ratio despite its being small. This paper presents a design technique for a cycloid reducer intended, because of those merits, for use in remote weapons systems of armed vehicles. In order to verify the performance of the cycloid reducer, we carried out experiments and analyzed the results systematically.