Coarse motion of `seal mechanism' with three degrees of freedom by using difference of frictional force

This is the authors' abstract. We don't add key points for this paper.

This paper deals with a small mobile device, a `seal mechanism', with three degrees of freedom (DOFs) for a scanning probe microscope. This device has two piezoelectric actuators, two controlled electromagnets A and B and electromagnet C, that generates a constant friction. The frictional forces at electromagnets A and B are alternated by an on-off control. The whole device wriggles with electromagnets C when the piezoelectric actuators extend and contract. The 3-DOF device can move in up to micrometre-steps in the x - and y -directions and up to submilliradian steps in the θ-direction. The movable range is infinite in principle. The seal mechanism performs as well as the inchworm mechanism. The seal mechanism needs a smaller number of controlled actuators and is driven by a smaller number of steps than the multiple-DOF positioning stages employing the inchworm mechanism.