Slip sensitive robot gripper system
First Claim
1. A gripping robot having a gripper characterized by(a) slip sensing means (1,2,3,4,5) at least partially mounted in the gripper and providing an output related to rapid acceleration of a linearly deformed resilient pad as it springs back to rest position;
- (b) slip determining control means (6), responsive to said slip sensing means and other inputs, to provide control of gripping action as a function of inputs including output from said slip sensing means, to provide a gripper control output; and
(c) servo means (7) responsive to said control means 6 to provide controlled gripping action to the gripper;
whereby an object held by the gripper may be imparted controlled slipping motion.
1 Assignment
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Accused Products
Abstract
A resilient gripper pad stores deformation energy just before the gripped object starts to slip, then rapidly accelerates as it suddenly releases the energy in the springback to rest position. An accelerometer in the resilient pad (corrected for ambient acceleration by differentiation with a nearby second accelerometer) provides information by which the control computer of a closed loop robot system mandates the manipulation of objects by controlled slipping. Controlled transitions of gripping (releasing) action evoked by the control computer provide related sequences of grip (slide) events, with one or more slip (pad chatter) events intervening at the threshold. Prior to the slide, there is an instant when the gripped object starts to slip on a slip pad on one digit of the gripper, but remains frictionally gripped by a resilient pad on the opposing digit. During this instant, the resilient pad deforms downward because of gravity on the gripped object. Next, when gripping force relaxes just a little more, the object slides free and the resilient pad springs back to its rest position. Two accelerometers, one mounted in the resilient pad to experience springback acceleration, and the other mounted in a complementary slip pad to experience ambient acceleration, are differentially compared. A computer manipulates signals related to motion experience of the gripper (grip or release) and detection (or absence) of springback acceleration, determines gripping, slipping or sliding status, and mandates the appropriate gripper action.
57 Citations
6 Claims
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1. A gripping robot having a gripper characterized by
(a) slip sensing means (1,2,3,4,5) at least partially mounted in the gripper and providing an output related to rapid acceleration of a linearly deformed resilient pad as it springs back to rest position; -
(b) slip determining control means (6), responsive to said slip sensing means and other inputs, to provide control of gripping action as a function of inputs including output from said slip sensing means, to provide a gripper control output; and (c) servo means (7) responsive to said control means 6 to provide controlled gripping action to the gripper; whereby an object held by the gripper may be imparted controlled slipping motion. - View Dependent Claims (2, 3, 4, 5)
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6. A slip sensor for a robot gripper having at least one resilient pad, which pad is subject to linear acceleration forces upon sudden release of stored linear energy as it springs back to rest position when a gripped object starts to slip, in addition to ambient acceleration forces occurring as the gripper moves about characterized by
accelerometer means physically mounted within the resilient pad so as to experience rapid acceleration upon springback of said resilient pad toward the rest position, and thus to provide a composite signal of springback acceleration plus ambient acceleration; -
means to correct said composite signal by cancelling the effect of ambient acceleration to provide a corrected signal; and means to detect slippage as a function of said corrected signal.
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Specification