Force and torque converter

• US 4,811,608 A
• Filed: 11/06/1986
• Issued: 03/14/1989
• Est. Priority Date: 12/18/1985
• Status: Expired due to Term

• Current Assignee: Labtec, Inc. (Logitech International SA)
• Original Assignee: Spatial Systems Pty Limited
• Inventors: Hilton, John A.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/927,915
• Time in Patent Office: 859 Days
• Field of Search: 73/862.04, 73/862.05, 73/862.06, 73/147, 74/471 XYZ
• US Class Current: 73/862.043
• CPC Class Codes: B25J 13/02 Hand grip control means handles or pedals for crane control B66C13/56; for measuring the force applied to control members G01L5/22; hand-held casings for switching devices, e.g. joy-sticks H01H9/0214
• CPC Class Codes: B25J 13/085 Force or torque sensors B25J13/082, B25J13/084 take precedence
• CPC Class Codes: G01L 1/24 by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
• CPC Class Codes: G01L 5/166 using photoelectric means
• CPC Class Codes: G01L 5/226 to manipulators, e.g. the force due to gripping
• CPC Class Codes: H01H 2239/052 Strain gauge
• CPC Class Codes: Y10T 74/20201 Control moves in two planes

Abstract

A force and torque converter provides command signals representative of a translational applied force and an applied torque extending about an axis substantially perpendicular to the axis along which the translational force is applied. The apparatus comprises of body to which the force and torque are applied, first and second connecting means attached to the body, means for biasing the connecting means to a central position and sensor means comprising two sensor devices arranged to detect a displacement force in each of the first and second connecting means respectively and which respond to the applied translation force and also respond to the torque to resolve the torque into a force comprising two components. A very important embodiment of the invention is arranged to operate in three dimensions and to resolve any applied torque into a respective components related to three mutually perpendicular axes. The apparatus can thus interpret operator applied hand signals for controlling an apparatus such as a computer based system.

Claims

1. An apparatus for providing output signals for use as command signals with respect to X, Y and Z mutually orthogonal axes, the signals being representative of a translational applied force and an applied torque, the apparatus comprising a base, a body to which the forces and torques are applied, resilient connecting means attached to the body and mounting the body for receiving force in any direction and torque about any axis and for urging the body to be displaced relative to the base, the resilient connecting means comprising a set of resilient connecting arm structures arranged in a three dimensional substantially uniform array with respect to said X, Y and Z axes, and sensor means arranged to detect a response to and to provide said output signals corresponding to components of an applied torque and components of an applied translational force with respect to said axes, wherein the base has a portion at which the X, Y and Z axes intersect and the connecting means comprise respective pairs of resiliently deformable connecting arms extending in the X, Y and Z directions, the arms of each pair extending away from the base portion in opposite directions to be connected to the body, and wherein the sensor means are adapted to detect a displacement in the respective connecting arms and provide said output signals, the sensor means detecting torque about the Y axis or displacement in the X direction at respective locations in the arms extending in the Z direction on opposite sides of the X axis, and detecting torque about the X axis or displacement in the Z direction at respective locations in the connecting arms extending in the Y direction on opposite sides of the Z axis.

2. Apparatus as claimed in claim 1 wherein said sensor means includes sensor elements associated with said resiliently deformable connecting arms which extend in the X direction and which was adapted to respond to a translational force in the Y direction or to a torque about the Z axis.

3. Apparatus as claimed in claim 2, wherein the respective connecting arms engage with portions of the body with respective freedoms of motion to a limited extent and respective constraints as follows:

X axis arms;

constrained in Y direction, free in Z and X direction and free to rotate about X axis;

Y axis arms;

constrained in Z direction, free in X and Y directions and free to rotate about Y axis;

Z axis arms;

constrained in X direction, free in Y and Z directions, and free to rotate about Z axis.

4. Apparatus as claimed in claim 3, and wherein the body comprises a housing member having a portion of the fixed base generally centrally disposed therein with a mounting arm of the fixed base extending out through the housing, and the resiliently deformable connecting arms extending along the respective X, Y and Z axes from the fixed base portion to engage with the housing at respective locations, each of the connecting arms having a ball-like tip engaging in a corresponding slot in the housing.

5. Apparatus as claimed in claim 4, wherein each of the connecting arms is of spring strip-like material, the strips extending in the X, Y and Z directions having their respective planes at right angles to one another.

6. Apparatus as claimed in claim 5 and wherein the sensor means comprises a sensor device associated with each of the pair of connecting arms extending respectively along the X, Y and Z axes and adapted to monitor the resilient displacement thereof, each sensor device including a shutter element disposed normally to interupt partially a beam of electromagnetic radiation from a source to an electromagnetically sensitive electronic device which is adapted to be connected into a circuit, the electrical characteristics of the device varying depending upon the amount of electromagnetic radiation incident thereon and thus corresponding to the position of the shutter.

7. An apparatus as claimed in claim 1 wherein each of said sensor means comprises a light emitting means and a light detecting means axially aligned substantially at right angles to the respective axis and a control mask connected to the respective resilient connecting arm structures and operable to vary the degree of interruption of light onto the light detecting means whereby the magnitude of the output signal is usable in determining the applied torque and/or applied force.

8. An apparatus for providing output signals for use as command signals with respect to X, Y and Z mutually orthogonal axes, the signals being representative of a translational applied force and an applied torque, the apparatus comprising a base, a body to which the forces and torques are applied, resilient connecting means attached to the body and mounting the body for receiving force in any direction and torque about any axis and for urging the body to be displaced relative to the base, the resilient connecting means comprising a set of resilient connecting arm structures arranged in a three dimensional substantially uniform array with respect to said X, Y and Z axes, and sensor means arranged to detect a response to and to provide said output signals corresponding to components of an applied torque and components of an applied translational force with respect to said axes, and wherein the connecting arm structures comprise a series of three connecting structures each comprising an arm extending from the body and pivotally connected to a leg through a joint having universal action through at least a limited range of angles, the leg extending normally in a direction substantially at right angles to an operating axis of the arm extending from the intersection of said X, Y and Z axes through said joint, said leg being attached to the base, and the sensor means being arranged to monitor displacements in the respective legs as follows:

the leg elongated in the X direction responds to displacement in the Z direction,

the leg elongated in the Y direction responds to displacement in the Z direction and in the X direction, and

the leg elongated in the Z direction responds to displacement in the X direction.

9. An apparatus as claimed in claim 8 wherein each of said sensor means comprises a light emitting means and a light detecting means axially aligned substantially at right angles to the respective axis and a control mask connected to the respective resilient connecting arm structures and operable to vary the degree of interruption of light onto the light detecting means whereby the magnitude of the output signal is usable in determining the applied torque and/or applied force.

10. An apparatus for providing output signals for use as command signals with respect to X, Y and Z mutually orthogonal axes, the signals being representative of a translational applied force and an applied torque, the apparatus comprising a base, a body to which the forces and torques are applied, resilient connecting means attached to the body and mounting the body for receiving force in any direction and torque about any axis and for urging the body to be displaced relative to the base, the resilient connecting means comprising a set of resilient connecting arm structures arranged in a three dimensional substantially uniform array with respect to said X, Y and Z axes, and sensor means arranged to detect a response to and to provide said output signals corresponding to components of an applied torque and components of an applied translational force with respect to said axes, wherein the connecting arm structures comprise a series of three connecting structures each comprising a mounting arm extending from the body and pivotally connected through a joint having universal action through at least a limited range of angles to a leg, the leg extending normally in a direction substantially at right angles to an operating axis of the arm extending from the intersection of the X, Y and Z axes through said joint, said leg being attached to the base, and the sensor means being arranged to monitor displacements of the respective legs in respective planes at right angles to the directions in which the respective legs extend from said universal joint towards the base.

11. Apparatus as claimed in claim 10 wherein the body further comprises a ball-like element and each connecting arm is a cranked arm having a minor portion mounting the arm on the body about a pivotal axis extending at right angles to the operating axis applicable to that arm and a major portion extending from a peripheral portion of the balllike element to the universal joint and at an angle to the operating axis.

12. Apparatus as claimed in claim 10 wherein each mounting arm is of a generally Y-shaped form and has a member extending transversely from one end portion for forming the universal joint connection with the associated leg, and the remote ends of the other arms have respective cross bores which are coaxial for pivotal attachment through elongated fixing elements to the body, the body being of ball-like form and having an outwardly extending flanged base, one of said other arms being connected to the flanged base and the other being inserted within the bore within the ball-like body, the axes of the cross bores in the respective Y shaped arms being located on the X, Y and Z axes of the apparatus, and the axes intersecting at the center of the ball-like body.

13. Apparatus as claimed in claim 12 and wherein each of the legs is in the form of a resilient connecting structure comprising a plate member forming a universal joint member for engaging with the mounting arm, and a resilient leg structure extending at right angles to the plate member and biasing the plate member to a central position and permitting the resilient displacement of the plate member in its own plane, the sensor means being arranged to monitor the displacements in a direction parallel to the plane of the plate.

14. Apparatus as claimed in claim 10, wherein each of the legs is in the form of a resilient connecting structure comprising a plate member forming a universal joint member for engaging with the mounting arm, and a resilient leg structure extending at right angles to the plate member and biasing the plate member to a central position and permitting the resilient displacement of the plate member in its own plane, the sensor means being arranged to monitor the displacements in a direction parallel to the plane of the plate.

15. Apparatus as claimed in claim 14 and wherein each of said resilient connecting structures comprises a rigid base member adapted to be fixed in space and forming at least part of said base of the apparatus, a rigid connector, and an array of resilient pins spaced normally parallel to one another and located spaced around an axis extending from the rigid base member and substantially at right angles thereto, the pins comprising a first set of at least 3 pins fixed to the rigid base member and fixed to the rigid connector, and a second set of at least 3 pins extending from the rigid connector through respective apertures in the rigid base member to be connected to said plate member.

16. An apparatus as claimed in claim 10 wherein each of said sensor means comprises a light emitting means and a light detecting means axially aligned substantially at right angles to the respective axis and a control mask connected to the respective resilient connecting arm structures and operable to vary the degree of interruption of light onto the light detecting means whereby the magnitude of the output signal is usable in determining the applied torque and/or applied force.

17. Apparatus for transforming applied forces into translational components along three mutually perpendicular axes and torque components about these three axes, the apparatus comprising a body to which the force is applied, three connecting members attached to the body and extending away therefrom such that in a central position of the body remote connection points on the respective connecting members lie along respective reference axes extending from a central point of the body, these reference axes being mutually perpendicular, respective leg means being pivotally connected to the respective connecting members at said connection points through universal joints of limited range and motion, biasing means being provided to bias the connecting members towards the central position, and sensor means for sensing displacement of each connecting member and/or each leg means whereby the nature of the applied force may be determined.

18. An apparatus as claimed in claim 17 wherein each of said sensor means comprises a light emitting means and a light detecting means axially aligned substantially at right angles to the respective axis and a control mask connected to the respective connecting members and operable to vary the degree of interruption of light onto the light detecting means whereby the magnitude of the output signal is usable in determining the applied torque and/or applied force.