Sub-Nanometer Positioning Combining New Linear Motor with Linear Motion Ball Guide Ways

A new type of linear motor described in this paper has some advantages compared with the usual types of motors. The attractive magnetic force between the stator (permanent magnets) and mover (armature) is diminished almost to zero. The efficiency is better because the magnetic flux leakage is very small, the size of motor is smaller and detent (force ripple) is smaller than the general motors. Therefore, we think that this motor is greatly suitable for ultra-precision positioning as an actuator. An ultra-precision positioning device using this motor and liner motion ball guide ways is newly developed. Moreover, the positioning performance is evaluated by a positioning resolution, devi-ational and dispersion errors. As the results of re-peated step response tests, the positioning resolution is 0.3 nm, the deviational error is –0.001nm and the dispersion error (3σ) is 0.29 nm. Consequently, the positioning device achieves sub-nanometer positioning. In addition, very large rigidity can be achieved. © Fuji Technology Press Ltd.