International Business Machines Corporation

Peter M Will

David D Grossman

Sherman S Wang

John E Griffith

Hugo A Panissidi

Glenmore Lorraine Shelton, Jr

Roger C Evans

George Arthur Folchi

Michael A Wesley

Myron M Kutcher

Moshe M Zloof

A method and apparatus for calibrating a robot and using the results of this calibration to compensate for inaccuracies of the robot and also to diagnose robot deterioration. The method includes moving the robot to a set of nominal positions, commanded by the robot controller or measured by position encoders built into the robot, and determining the associated actual positions by measuring the robot position with an independent accurate measuring means or by aligning the robot end effector with an accurate calibration mask. The calibration results are stored and subsequently used to compensate for robot inaccuracy so that the robot moves to the actual desired positions.

Method and apparatus for calibrating a robot to compensate for

A servo-control valve for a linear hydraulic motor wherein the control valve piston is isolated from the side loading of a cam and roller by employing a cam follower plunger, as a separate detached element coaxial with the piston. The valve piston and the cam follower plunger are maintained in intimate contact due to the constant back pressure applied by the hydraulic system. The plunger is encased in a cylindrical array of balls which are preloaded between the plunger and the piston chamber walls such that the plunger experiences essentially only rolling friction, but no sliding friction, as the plunger moves. This form of preloading of the balls eliminates the backlash associated with clearance around the plunger.

Servo-control valve for a linear hydraulic motor

A computer-controlled-manipulator gripper with a set of three-degree-of-freedom force sensors on each finger having strain gauges and 90.degree. shift in orientation of the sensors includes an asymmetric, offset relationship of the location and orientation of analogous sensors on the two fingers in order to obtain different measurements from the two fingers.

Asymmetric six-degree-of-freedom force-transducer system for a

A mechanical manipulator which includes fingers under the control of a computer, antenna sensing means mounted on such fingers and extended and retracted from the fingers under the control of the computer, means for detecting the contact or proximity of the extended antenna sensing means with a workpiece, means responsive to the antenna sensing means for retracting the sensing means from interference with the workpiece and for adjusting the control of the fingers. The fingers are adapted for X, Y and Z linear motions and provides pitch, yaw and roll angular motion. The retractable antenna sensing means resembles a whisker which extends from the finger and makes contact with or approaches the workpiece. The antenna sensing means may include a retractable pneumatic back pressure sensor via the back pressure of a fluid in the supply, created when the fluid impinges on the workpiece. The retractable antenna whisker bends more readily than the rigid finger. Therefore, contact with an object will not cause displacement of the object as a rigid finger would. Computer logic circuits receive signals representing the displacement and positions of both the antenna sensing means as well as the manipulator fingers and coordinates both sets of signals to determine the orientation and position of the workpiece and the shape of the workpiece.

Computer controlled pneumatic retractable search sensor

A quasi-liquid vise is provided for clamping irregularly shaped workpieces which comprises an open-topped vessel into which a workpiece may be inserted, a particulate fluidizable material located within and, substantially filling said vessel, pressure means connected to said vessel for introducing a gas or fluid therein to fluidize said particulate material, and means for applying a vacuum to said vessel and the particulate material to substantially solidify said particulate material when it is desired to clamp a workpiece therein. The solidifying effect of said vacuum applied to said particulate material may be enhanced by utilizing alternate layers of different sized particulate material wherein smaller particles fill voids and enhance the vacuum effect and hence the rigidity of the particulate material when it is desired to solidify same. Two additional approaches to improving the vacuum solidification effect include coating relatively dense particles with a somewhat resilient deformable material whereby better sealing action will be effected. Also, uniquely shaped particles may be utilized wherein a more rigid interlocking particle effect will be obtained upon application of the vacuum.

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Norwalk, CT, United States of America

Peter M Will