System for determining part presence and grip pressure for a robotic gripping device

A method for determining if a robot gripper assembly has acquired a work piece, the robot gripper assembly including at least two opposing fingers, said method comprising the steps of:

• (a) moving the at least two opposing fingers to a predetermined position to acquire the work piece, the predetermined position being different than an expected work piece dimension, said moving step being performed in response to a command signal sent to the servomotor controlled robot gripper assembly;
• (b) tracking an actual position of the at least two opposing fingers when movement of the at least two opposing fingers has been completed in the performance of said closing step using the number of rotations of said tracking step;
• (d) comparing the actual position to the predetermined position to determine a position error;
• and
• (e) recognizing that a work piece has been acquired by the at least two opposing fingers if the position error is not zero.

A method for determining if a robot gripper assembly has acquired a work piece and for determining if the work piece is within dimension tolerances, the robot gripper assembly including at least two opposing fingers, said method comprising the steps of:

• (a) closing the at least two opposing fingers to a predetermined position to acquire the work piece, the predetermined position being less than an expected work piece dimension tolerance range, said closing step being performed in response to a command signal sent to the servomotor controlled robot gripper assembly;
• (b) tracking motion of the at least two opposing fingers during said closing step until movement of the at least two opposing fingers has been completed to determine an actual position;
• (d) determining if the actual position is within the expected work piece dimension tolerance range to determine a position error;
• and
• (e) recognizing that a work piece has been acquired by the at least two opposing fingers if the actual position is greater than the predetermined position and recognizing that the work piece is dimensionally acceptable if the actual position is within the expected work piece dimension tolerance range.

A method for determining if a servo controlled robot gripper assembly has acquired a work piece, the servomotor controlled robot gripper assembly including at least two opposing fingers, said method comprising the steps of:

• (a) commanding the servomotor controlled robot gripper assembly to close the at least two opposing fingers to a predetermined position to acquire the work piece, the predetermined position being less than an expected work piece dimension;
• (b) measuring a rotation quantity of the servomotor until movement of the at least two opposing fingers has been completed in response to said commanding step;
• (c) using the rotation quantity to determine an actual position of the at least two opposing fingers when movement of the at least two opposing fingers has been completed in response to said commanding step;
• (d) comparing the actual position to the predetermined position to determine a position error;
• and
• (e) recognizing that a work piece has been acquired by the at least two opposing fingers if the position error is not zero.

A method for determining if a robot gripper assembly has acquired a work piece, the robot gripper assembly including at least two opposing fingers, said method comprising the steps of:

• (a) commanding the robot gripper assembly to move the at least two opposing fingers to a predetermined position to acquire the work piece, the predetermined position being different than an expected work piece dimension;
• (b) measuring an actual position of the at least two opposing fingers when movement of the at least two opposing fingers has been completed in response to said commanding step;
• (c) comparing the actual position to the predetermined position to determine a position error;
• and
• (d) recognizing that a work piece has been acquired by the at least two opposing fingers if the position error is not zero.