Gripping tool, gripping system, and evaluation method of gripping performance

A gripping tool, comprising:

• a gripper including a first portion and a second portion and being flexible;
• a plurality of granular materials provided in a first space between the first portion and the second portion;
• a first port;
• and
• a second port,
• the first portion being configured to contact a workpiece and including
• a concave portion recessed toward a first direction, the first direction being from the first portion toward the second portion, and
• a convex portion protruding toward a second direction opposite to the first direction and being provided around the concave portion,
• the first port communicating with the first space;
• a first pipe being connected to the first space and configured to depressurize the first space,
• the second port having a hole piercing the concave portion and the second portion along the first direction,
• a second pipe being connected to the second port and configured to depressurize a second space surrounded with the concave portion and the convex portion,
• the gripping tool being configured to grip the workpiece by depressurizing the first space in a state in which the first portion is deformed by being caused to contact the workpiece,
• in a state in which the first portion does not contact the workpiece, a dimension in a perpendicular direction of the concave portion being longer than a dimension in the perpendicular direction of the hole, the perpendicular direction being perpendicular to the first direction,
• the granular materials being provided between the convex portion and the second portion,
• a diameter of at least a portion of the granular materials being less than 1774 μm.

An evaluation method of gripping performance of a gripping tool being configured to grip and lift an object, the method comprising:

• changing a curvature of an object to be gripped while measuring a gripping force of the gripping tool at each of the curvatures;
• and
• defining an integral of the gripping force over the curvature to be the gripping performance and evaluating the gripping performance of the gripping tool, wherein the gripping tool includes:
• a gripper including
• a first portion being configured to contact the object and being flexible,
• a second portion opposing the first portion and being flexible, and
• a plurality of granular materials provided in a first space between the first portion and the second portion,
• a holder holding an outer perimeter of the first portion and an outer perimeter of the second portion,
• the gripping tool grips the object by solidifying the granular materials by depressurizing the first space in a state in which the first portion is deformed by being caused to contact the object,
• when the first portion is deformed by being caused to contact the object, the second portion is more deformable than the holder in a first direction, the first direction being from the first portion toward the second portion, and
• a diameter of at least a portion of the granular materials is changed while evaluating the gripping performance at each diameter.