Jamming Gripper-Inspired Soft Jig for Perceptive Parts Fixing

To achieve precise and time-efficient operation to ensure stable and reliable product assembly, custom-made jigs have been developed for each assembly part. However, designing these jigs is a time-consuming task. Therefore, this study proposes a jamming gripper-inspired flexible jig using a soft membrane consisting of transparent beads and oil with an adjusted refractive index. The proposed jig is equipped with a hydraulic drive system with visual control of the amount of transparent oil inside the jig. The proposed system enables parts fixing by creating a jammed state while maintaining optical transparency, thereby facilitating the visual sensing of the jig’s membrane from camera sensors embedded in the jig. Furthermore, a sensing method was developed to perform a precise assembly without external sensors to estimate the pose of an object based on the proposed point-to-function iterative closest point. The results show that the proposed system successfully estimates the orientation at a root mean square error of less than ang 4 when the position is varied from
$\mathrm {0 mm}$
to
$\mathrm {20 mm}$
and the angle is varied from ang 0 to ang 20. Furthermore, it can repeatedly fix the object in any orientation from ang 0 to ang 20 at a position of less than
$\mathrm {0.5 mm}$
and an angle of less than ang 1.1.