2021 Volume 39 Issue 6 Pages 533-544
This paper presents a nonprehensile manipulation using an underactuated mechanism, in which three degrees of freedom (DoF) of a planar object are controlled on a vibrating plate driven by only one actuator. First, the model of a manipulator with a plate end effector is proposed. The manipulator employs an underactuated mechanism including an active joint and multiple passive viscoelastic joints, in which the joint axes are arranged nonparallel to each other. Based on the model, the orbit of the plate for a sinusoidal displacement input to the active joint is theoretically derived. It is revealed that the orbit becomes ellipse-like and the orbital direction has a potential to be switched according to the increase of the input frequency. Subsequently, the contribution of the switching of the orbital direction to the three-DoF manipulation of the object is explored via trajectory maps of point masses. Eight primitives utilizing the plate orbits in both counter-clockwise and clockwise directions are designed. Finally, the proposed method is demonstrated by experiments.
