Browse Prior Art Database

Servo Controlled Robot Gripper

IP.com Disclosure Number: IPCOM000040738D
Original Publication Date: 1987-Dec-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Smith, GM: AUTHOR

Abstract

A method of controlling the gripping force of a robot jaw is disclosed requiring no additional circuitry or control lines. When picking up a part where size and weight are known, the jaw opening is initially controlled to be slightly larger than the part and moved over the part. Then the servo system driving the jaw motor is set to drive the jaws to an opening slightly less than the part size calculated to apply a known force to grip the part. In a robotic assembly cell one or more mechanical grippers are normally provided to enable parts to be picked up, and it is quite common for the jaw openings of these to be servo-controlled to allow the opening to be set just larger than the particular part to be opened while moving to the part.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 61% of the total text.

Page 1 of 2

Servo Controlled Robot Gripper

A method of controlling the gripping force of a robot jaw is disclosed requiring no additional circuitry or control lines. When picking up a part where size and weight are known, the jaw opening is initially controlled to be slightly larger than the part and moved over the part. Then the servo system driving the jaw motor is set to drive the jaws to an opening slightly less than the part size calculated to apply a known force to grip the part. In a robotic assembly cell one or more mechanical grippers are normally provided to enable parts to be picked up, and it is quite common for the jaw openings of these to be servo-controlled to allow the opening to be set just larger than the particular part to be opened while moving to the part. As the required movement of the jaws to actually close on the part is minimized, so is the time required and so the operation is speeded up. Also, with a crowded assembly it is often necessary to control the jaw opening when releasing a part to prevent interference with already placed parts. It is also very useful to be able to control the force exerted by the gripper when grasping a part. With an electrically driven gripper, the force applied by the gripper jaws will depend on the torque available from the motor modified by any gear ratio or mechanical advantage in the power transmission from the motor to the jaws. Thus, the exerted force could and has been controlled by controlling the motor armature...