(SG-I (1976), SG-II (1978), SG-III (1984)). The soft gripper is a snake-like mechanism that can flexibly grab an optionally shaped object. To flexibly grasp an object, it must be possible to create a uniform grasping force on all the gripper surfaces while wrapping around the object. This was accomplished in the action of the soft gripper in the following way.

First, let us consider bending moment M(s) which is created on the inside part of the member when adding a distributed load to a cantilever beam. This may be reduced in terms of secondary functions as in Fig. 1 . From this, if the gripper is assumed to be a kind of beam which has countless motors, when considering the moment in which there are secondary function changes by these motors facing from the base toward the tip, this moment generates a uniform force along the beam to the exterior part. However, using countless motors cannot be done.

Thus, we developed the soft gripper mechanism in Fig. 2 . This is a mechanism in which the joints and pulleys are all connected to rotate independently, and the wire fixed to the head joint is pulled by coiling around all the pulleys. In this mechanism, when the wire is pulled, a bending moment proportional to the radius of the pulley is generated on each joint. For that reason, when the pulley radius is designed to change in terms of secondary functions and the wire coiling around the pulleys is pulled, the moment of distribution described above is obtained, and uniform grasping is possible. The grip release motion is conducted by pulling the series of pulleys of the same radius in the opposite direction. When this is done, the device is housed by winding it up in a coil shape from the tip.

Photo. 1, indicates the conditions by which the primary model grasps from the housed state. Photo. 2, indicates a large-scale model that was developed as a gripper for a robot assisted by a human command to grasp and hold up a human body. Drive systems for vertical grasping and for horizontal grasping are provided. Photo. 3, is belt-driven type three-fingered model.