Controller arm for a remotely related slave arm

• US 4,160,508 A
• Filed: 08/19/1977
• Issued: 07/10/1979
• Est. Priority Date: 08/19/1977
• Status: Expired due to Term

• Current Assignee: Frosch Robert A Administrator of The National Aeronautics and Space Administration With Respect To An Invention of, John K. Salisbury Jr
• Original Assignee: Frosch Robert A Administrator of The National Aeronautics and Space Administration With Respect To An Invention of, John K. Salisbury Jr
• Inventors: Salisbury, John K. Jr., Frosch, Robert A. Administrator of the National Aeronautics and Space Administration, with respect to an invention of
• Primary Examiner(s): Husar, Francis S.
• Assistant Examiner(s): Abraham, George F.
• Application Number:
  US05/826,202
• Time in Patent Office: 690 Days
• Field of Search: 214/1 CM
• US Class Current: 414/4
• CPC Class Codes: B25J 13/085 Force or torque sensors B25J13/082, B25J13/084 take precedence
• CPC Class Codes: B25J 17/025 mounted in series
• CPC Class Codes: B25J 19/002 using counterweights
• CPC Class Codes: B25J 3/04 involving servo mechanisms servo-actuated heads B25J15/02
• CPC Class Codes: B25J 9/06 characterised by multi-articulated arms

Abstract

A segmented controller arm configured and dimensioned to form a miniature kinematic replica of a remotely related slave arm. The arm includes a plurality of joints for affording segments of the arm simultaneous angular displacement about a plurality of pairs of intersecting axes, a plurality of position sensing devices for providing electrical signals indicative of angular displacement imparted to corresponding segments of the controller shaft about the axes, and a control signal circuit for generating control signals to be transmitted to the slave arm. The arm is characterized by a plurality of yokes, each being supported for angular displacement about a pair of orthogonally related axes and counterbalanced against gravitation by a cantilevered mass affixed thereto whereby the controller arm may be released without introducing unwanted motion in the slave arm resulting from gravitation of segments of the master arm.

Claims

1. In a manipulator system characterized by an articulated slave arm having a plurality of pivotally connected segments for performing a variable task at a work site, and a controller remotely related to the work site and connected to the slave arm, the improvement comprising:

an articulated controller arm characterized by a segmented controller shaft including a plurality of controller shaft segments, each segment of said plurality being configured and dimensioned to form a miniature kinematic replica of a corresponding segment of the slave arm and supported for relative angular displacement about a pair of intersecting axes duplicatable by the slave arm, said pair of axes intersecting and defining therebetween a constant included angle of 45°

;

an articulated skeletal body for supporting said controller shaft including a plurality of pivotal segments symmetrically related to said controller shaft and supported for angular displacement about pivotal axes normally related to one axis of said pair of intersecting axes.

2. The improvement of claim 1 wherein at least one segment of said plurality of pivotal segments includes a pair of coaxially aligned sections, each section of said pair being supported for angular displacement relative to the other section of the segment about an axis common thereto.

3. The improvement of claim 2 further comprising motion restraint means for restraining each of the pivotal segments of the skeletal body against gravitation about said pivotal axes.

4. In a manipulator system characterized by an articulated slave arm having a plurality of pivotally connected segments for performing a variable task at a work site, and a controller remotely related to the work site and connected to the slave arm, the improvement comprising:

A. an articulated controller arm characterized by a segmented controller shaft including a plurality of controller shaft segments, each segment of said plurality being configured and dimensioned to form a miniature kinematic replica of a corresponding segment of the slave arm and supported for relative angular displacement about a pair of intersecting axes duplicatable by the slave arm;

B. an articulated skeletal body for supporting said controller shaft including a plurality of pivotal segments symmetrically related to said controller shaft and supported for angular displacement about pivotal axes normally related to one axis of said pair of intersecting axes;

C. at least one segment of said plurality of pivotal segments including a pair of coaxially aligned sections, each section of said pair being supported for angular displacement relative to the other section of the segment about an axis common thereto;

D. motion restraint means for restraining each of the pivotal segments of the skeletal body against gravitation about said pivotal axes;

E. said motion restraint means including a counterbalancing mass rigidly affixed in cantilevered relation to each segment of said skeletal body and characterized by a moment acting about the pivotal axis in opposition to the moment of the mass of the arm about the pivotal axis.

5. The improvement of claim 4 further comprising means for providing a plurality of electrical signals indicative of the instantaneous angular relation of the segments about said pair of axes, said means for providing a plurality of electrical signals including a pair of electrical potentiometers connected with each segment of the controller shaft for providing an output voltage varying proportionally with relative angular displacement of the segment.

6. A manually operable controller for a remotely related articulated slave arm having a terminal effector and characterized by a plurality of slave arm segments, each being angularly displaceable about a pair of axes, comprising:

A. a segmented controller shaft comprising a miniature kinematic replica of the slave arm including means defining a shoulder joint for affording adjacent segments of the arm mutually relative angular displacement about a first pair of intersecting axes, means defining an elbow joint for affording adjacent segments of the arm mutually relative angular displacement about a second pair of intersecting axes, means defining a wrist joint for affording adjacent segments of the arm mutually relative angular displacement about a third pair of intersecting axes, and means defining a base joint for affording said segments angular displacement about a common axis;

B. a rotatable terminal shaft including signal generating means for providing effector control signals for controlling the terminal effector of the slave arm;

C. signal generating means for generating electrical signals indicative of mutually relative angular displacement imparted to adjacent segments of said controller shaft;

D. means including a body for housing said controller shaft including a shoulder yoke supported for simultaneous angular displacement about a pair of orthogonally related axes passing through the shoulder joint, an elbow yoke supported for simultaneous angular displacement about a pair of orthogonally related axes passing through the elbow yoke, and a wrist yoke supported for simultaneous angular displacement about a pair of orthogonally related axes passing through said wrist joint; and

E. means for restraining each of said yokes against gravitation, including a cantilevered mass affixed to each of the yokes characterized by a moment acting in opposition to the moment of the arm acting about one axis of the pair of orthogonally related axes about which the yoke is supported for angular displacement.

7. The controller of claim 6 wherein said signal generating means comprises a pair of electrical potentiometers connected in a signal transmission circuit and mounted in each of the joints.

8. In a manipulator system characterized by an articulated slave arm having a plurality of pivotally connected segments and adapted to perform a variable task at a work site, an improved, manually operable controller arm characterized by seven degrees-of-freedom comprising:

A. a segmented controller shaft comprising a miniature kinematic replica of the slave arm including means defining a first joint for affording adjacent segments of the shaft simultaneous angular displacement about a first pair of intersecting axes, means defining a second joint for affording adjacent segments of the shaft simultaneous angular displacement about a second pair of intersecting axes, means defining a third joint for affording adjacent segments of the shaft simultaneous angular displacement about a third pair of intersecting axes and means defining a base joint for affording all of the segments simultaneous angular displacement about a further axis;

B. output means located at each of said joints and connected with the segments of the shaft for providing an electrical output indicative of relative angular displacement of the segments of the controller shaft;

C. a plurality of yokes pivotally connected for mutual relative angular displacement about pivotal axes supporting the segments of the shaft, and counterbalancing means for restraining the segments of the shaft against gravitation-induced displacement.

9. The controller arm of claim 8 wherein each yoke is supported for rotation about a rotary axis normally related to the pivotal axis.

10. The controller arm of claim 9 wherein said output means includes a first potentiometer having a wiper blade support shaft the axis of which bisects the included angle defined by said rotary axis and said pivotal axis and a second potentiometer having a wiper blade support shaft the axis of which is coincident with the rotary axis thereof.

11. The controller arm of claim 10 wherein the counterbalancing means includes a cantilevered mass affixed to each of the yokes, each mass having a moment about the pivotal axis of the yoke to which it is affixed equal to the moment of the arm acting about the axis in opposition thereto.