Wearable haptic display by the use of a Particle Mechanical Constraint

A Particle Mechanical Constraint is a soft vinyl tube that envelops Styrofoam beads. It has 6 degrees-of-freedom including compression, elongation, bending and twisting. By exhausting the inside air the PMC solidifies and constraints all degrees-of-freedom in an arbitrary shape. The stiffness of the PMC is proportional to the inside air pressure. Viscosity is also controlled virtually by changing the inside air pressure in proportion to the speed of transformation of the PMC. By the use of a PMC, we developed a wearable haptic display that provides a sensation of contacting a wall and moving in water with viscosity. We also developed an upper-limb orthotic that constrains shoulder and elbow movements. PMC is adequate as a wearable human interface because it is light, soft and safe. In addition, it is an inherently passive device that never exerts excessive force when broken.