Stress sensing device, tactile sensor, and grasping apparatus

A tactile sensor comprising:

• a plurality of the stress sensing devices for sensing a shear force acting in a shear direction and a pressing force perpendicular to the shear direction, the stress sensing devices being arranged in an array, each of the stress sensing devices including
• a support body including an opening defined by a pair of straight parts perpendicular to a sensing direction of the shear force and parallel to each other,
• a support film on the support body and closing the opening, the support film having flexibility,
• a first piezoelectric part configured to output an electrical signal by bending, the first piezoelectric part being disposed over the support film and straddling an inside portion and an outside portion of the opening along at least one of the straight parts of the opening as seen in plan view when the support body is viewed from a thickness direction of the support film,
• a second piezoelectric part configured to output an electrical signal by bending, the second piezoelectric part being disposed to the inside portion of the opening and set apart from the first piezoelectric part as seen in the plan view, and
• an elastic layer covering the first piezoelectric part, the second piezoelectric part, and the support film.

A grasping apparatus for grasping an object comprising:

• a tactile sensor including a plurality of the stress sensing devices for sensing a shear force acting in a shear direction and a pressing force perpendicular to the shear direction, the stress sensing devices being arranged in an array, each of the stress sensing devices having
• a support body including an opening defined by a pair of straight parts perpendicular to a sensing direction of the shear force and parallel to each other,
• a support film on the support body and closing the opening, the support film having flexibility,
• a first piezoelectric part configured to output an electrical signal by bending, the first piezoelectric part being disposed over the support film and straddling an inside portion and an outside portion of the opening along at least one of the straight parts of the opening as seen in plan view when the support body is viewed from a thickness direction of the support film,
• a second piezoelectric part configured to output an electrical signal by bending, the second piezoelectric part being disposed to the inside portion of the opening and set apart from the first piezoelectric part as seen in the plan view, and
• an elastic layer covering the first piezoelectric part, the second piezoelectric part, and the support film;
• at least one pair of grasp arms configured to grasp the object, the grasp arms having the tactile sensor disposed on a contact face that contacts the object;
• a grasp sensing unit configured to sense a slippage state of the object based on the electrical signal output by the tactile sensor;
• and
• a drive control unit configured to control driving of the grasp arms based on the slippage state.