Development of light and compact clutch device using jamming effect

Our goal is to develop a general passive wrist structure for a robot manipulator. It can change its d.o.f. of passivity to adapt various states of contact between a work and environment. For this goal, we have to have a clutch / brake device which is compact and light. There are several clutch mechanism such as electromagnetic clutch, MR (Magnetorheological) clutch, etc. But these clutches use electromagnetic force to generate friction or shearing force. So they require copper wire coils, metal part, etc. which is large and heavy. In this study, we adopt jamming effect device to develop a clutch. Jamming effect device does not require electromagnetic force and it allows to put power source to generate gripping force outside. So we think it can be compact and light. Compactness and lightness are advantage of our clutch. One disadvantage of this clutch is that there exist some resistant force when this clutch is unlocked. When the shaft rotates, blade should move through the powder. So some resistant force should be generated.