Bifinger hand for an industrial robot and a method of controlling the operation of the bifinger hand
AssigneeFanuc Corporation
InventorsKazuhisa Otsuka, Akira Tanaka
Life of this patent
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Abstract
A robot hand is provided with a bifinger unit integrally including a pair of fingers for grasping a workpiece therebetween, a finger feed unit for moving the pair of fingers between a predetermined open position and a closed grasping position, a single servomotor driving the feed mechanism to thereby move the pair of fingers so that a constant predetermined holding force is applied to the workpiece from the pair of fingers during the grasping operation of the fingers of the bifinger unit of the robot hand irrespective of the weight, the size, the shape or the surface condition of the workpiece.
Claims10
A robot hand provided with a bifinger unit, having a pair of relatively movable fingers for grasping a workpiece therebetween, comprising:
- a palm means formed as a base portion of said robot hand;
- a pair of finger-support means for removably supporting the pair of fingers, said finger support means being movable mounted on said palm means;
- finger feed means mounted on said palm means for providing said pair of finger-support means with a feed motion along a predetermined axis to therein relatively move said pair of fingers between a grasping position thereof and a predetermined releasing position thereof distant from said grasping position;
- a single servomotor means mounted on the palm means of said robot hand for driving the finger feed means;
- and
- control means for controlling an operation of said servomotor to therein adjust said grasping position of said pair of fingers so that a predetermined optimum holding force is applied to the workpiece based upon weight, size, shape, hardness, and surface condition of the workpiece, wherein said control means is connected to a holding force input means by which holding force data, necessary for determining said predetermined optimum holding force of the workpiece, is input into said control means.
A method of controlling the operation of a robot hand provided with a bifinger unit having a pair of grasping fingers movable between a relatively closed position for grasping a workpiece and an open position for releasing the workpiece, a feed mechanism for providing said pair of grasping fingers of said bifinger unit with a one-directional feed motion, and a servomotor for driving said feed mechanism, wherein the method comprising the steps of:
- determining beforehand data on holding forces applied to various workpieces by said pair of fingers of said bifinger unit in accordance with a weight, a size, a shape, and a surface condition of each of said various workpieces, and storing said data of said holding forces in a memory means;
- determining an optimum holding force necessary for grasping an actual workpiece from said data of holding forces stored in said memory means;
- determining an optimum output torque from an overall range of torque exerted by said servomotor, in accordance with the optimum holding force necessary for grasping said actual workpiece;
- controlling the operation of said servomotor until the optimum output torque corresponding to the optimum holding force is exerted by said servomotor while said pair of fingers of said bifinger unit move to apply a gradually increasing holding force to said actual workpiece;
- and
- terminating the movement of said pair of fingers immediately when the output torque exerted by said servomotor attains the optimum output torque during grasping operation of said bifinger unit of said robot hand.
Dependencies are inferred from the claim text.