International Business Machines Corporation

Hugo A Panissidi

Chao N Liu

Peter M Will

Henry E Aviles

Noel M Herbst

Henry E Wattenbarger

Glenmore Lorraine Shelton, Jr

Jane A Gregory

A multi-degree of freedom force transducer is provided for measuring forces applied to gripper fingers in a manipulator when grasping an object therebetween. The transducer includes a pair of force sensor assemblies rigidly connected at a first end to a respective finger and at a second end to a drive member for the gripper. A plurality of parallel beam structures are contained in each of the force sensor assemblies, each consisting of a pair of flat parallel flexure members, each member bridging opposite sides of a gap in the structure. These parallel beam structures are oriented so that the axis perpendicular to the planar surfaces of the parallel flexure members are orthogonal to one another, providing the capability of measuring the force applied to an object held by the gripper in the X, Y and Z axial directions. A strain gage of a pair of strain gages is located at a predetermined opposite maximum flexure point of each flexure member of said parallel beam structures, so as to measure the flexure of the member at the predetermined flexure points, which flexure is indicative of the force vector along the axis perpendicular to the parallel flexure members. In another embodiment the junction between the flexure member and the wall of the strain gage assembly is radiused or curved so that the maximum flexure point is spread out, giving longer life and enhanced measurement accuracy.

Tri-axial force transducer for a manipulator gripper

The gripping apparatus described comprises a four-bar linkage arrangement for so controlling movement of the two pairs of parallel beams and fingers operatively connected thereto as to cause the gripping surfaces of the fingers to concurrently move in rectilinearly aligned paths and remain parallel throughout their excursion during gripping and releasing of an article and apply a constant gripping force to the article irrespective of the extent to which the fingers are moved toward each other into gripping contact. The beams are pivotally connected directly at their one ends, and also intermediate their ends via links, to a fixed member; and the beams at their opposite ends have a pin-in-slot connection with the fixed member. When force is applied to the links to operatively cause the fingers to grip the article, the links will rock and the arc described by each beam will be accurately cancelled by the arc generated by each link.

Article gripping apparatus

An air pressure counterbalance system is provided for an X Y Z orthogonal manipulator wherein the effect of gravity on a manipulator arm joint is counterbalanced both while hydraulic pressure is supplied to the hydraulic motors and also when the motive power is suspended. The air pressure counterbalance force is produced by a piston operating in an air cylinder in the direction of the gravity axis as the manipulator hand is raised or lowered. A selected constant air pressure is supplied to the counterbalance cylinder through an air pressure regulating system. In a preferred embodiment, a program-controlled counterbalance system is provided wherein the weights of various tools to be grasped by the manipulator fingers during a program are stored in CPU memory. The manipulator program selects the appropriate counterbalancing force to compensate for the predetermined tool weight and adjusts an air pressure regulator accordingly.

Programmable air pressure counterbalance system for a manipulator

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 pressure sensing device having applicability as a simple pressure sensor and which is particularly adapted for use as a pen in a Signature Verification System, said device including a unique mounting structure for the pressure sensing stylus by flexible support means mounted on a substantially rigid base. The support means has a pressure sensing element mounted thereon. The flexible support means comprises two spaced members so disposed that their deflections and the output of the pressure sensing element are substantially independent of the angle of pressure on the stylus. In the special purpose embodiment useful for Signature Verification the stylus comprises a pen and the device further includes two orthogonally disposed accelerometers for sensing accelerations of said pen during the writing of a signature.

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Peekskill, NY, United States of America

Hugo A Panissidi