Apparatus for providing a displacement representative of the magnitude of a signal

• US 4,044,305 A
• Filed: 03/17/1975
• Issued: 08/23/1977
• Est. Priority Date: 03/17/1975
• Status: Expired due to Term

• Current Assignee: Charles Stark Draper Laboratory Incorporated
• Original Assignee: Charles Stark Draper Laboratory Incorporated
• Inventors: Oberbeck, George A.
• Primary Examiner(s): Strecker, Gerard R.
• Application Number:
  US05/558,960
• Time in Patent Office: 890 Days
• Field of Search: 324/125, 324/137, 324/146, 324/147, 324/151, 324/152, 324/154, 324/133, 310/93, 310/103, 335/224, 335/225
• US Class Current: 324/154.00R
• CPC Class Codes: G01R 1/02 General constructional details
• CPC Class Codes: G01R 1/10 Arrangements of bearings
• CPC Class Codes: G01R 1/16 Magnets
• CPC Class Codes: G01R 5/14 Moving-iron instruments

Abstract

A device for providing a displacement representative of the magnitude of a signal. The device typically includes a rotor having a plurality of sections of high permeability material separated by areas of high reluctance. A magnetic flux is applied to a section of the rotor to produce an elastic restraint torque varying with angle, while another high permeability section responds to variations in the magnetic flux caused by the signal to produce a torque representative of the signal magnitude. This latter torque moves the rotor to the point where the restraint torque increases sufficiently to balance the signal torque. The resultant angle of rotation represents signal magnitude. The device may also be operated to provide a signal output representative of an input torque or force.

Claims

1. Apparatus for providing a displacement proportional to a signal magnitude comprising:

an element having first and second sections of high magnetic permeability separated by a spacer of low magnetic permeability;

means for motionally suspending the element;

means for applying a first magnetic flux to said element and to the first and second sections thereof;

said first and second sections being configured to provide a variation in the reluctance for said first magnetic flux through the first section with motion of said element and a generally lesser variation in reluctance to the first flux through the second section with motion of the element thereby producing a force on said element dependent upon position thereof; and

means for applying a second flux representative of said signal through said element;

said first and second sections being further configured to provide a variation in the reluctance of said second section to said second flux with motion of said element without substantially changing said force resulting from said first flux;

said element moving in response to the second flux applied in response to said signal to a point representative of said signal.

7. The apparatus of claim 1 further including:

means for varying the first flux in response to a further signal thereby to provide motion of said element representative of the ratio of said signal and said further signal.

2. Apparatus for providing a displacement representative of the magnitude of a signal comprising:

an element having a plurality of high permeability sections separated by an area of low permeability;

means for directing magnetic flux through said element;

means for generating a magnetic flux for direction through the sections of said element;

said sections being configured to provide a restraint force on said element urging it toward a predetermined position with respect to said flux directing means, the restraint force increasing with displacement of said element from said predetermined position;

means for generating further magnetic flux representative of the magnitude of said signal to direct a flux through the sections of said element;

said sections being configured to force said element to displace from said predetermined position in response to said further magnetic flux;

said element displacing in response to the further flux to a position where the force from said further flux balances the restraint force from the first mentioned flux.

3. The apparatus of claim 2 wherein the force responsive to said further flux is generally independent of the displacement of said element and said restraint force resulting from the first mentioned flux in said element generally increases linearly with a parameter of displacement for said element.

4. The apparatus of claim 3 wherein:

said element is suspended for rotational movement; and

the forces resulting from said first and further fluxes induce a torque on said element.

5. Apparatus for producing a motional response representative of an applied signal magntidue comprising:

an element sectioned into regions of high magnetic permeability separated by regions of low permeability;

means for motionally suspending said element;

means for applying a flux through the sections of said element in a predetermined pattern;

said sections of said element being configured to induce an elastic restraint force on said element in response to said flux urging it toward a predetermined position in the range of motion for said element;

means responsive to the signal for adjusting the pattern of flux applied through said element;

said sections being further configured to induce a motion of said element from said predetermined position in response to the adjusted pattern of flux applied to said element.

6. Apparatus for providing a rotation representative of the magnitude of a signal and including:

a rotationally suspended element;

a first set of magnetic poles for applying flux to said element;

a second set of magnetic poles for applying flux to said element;

said element having a first section of high permeability material extending on the surface of said element partially across each of the pole faces of said first and second sets of magnetic poles;

said element further having at least one second section of high permeability material magnetically isolated from the fist section and extending on the surface of said element partially across poles from different sets to poles to provide a low magnetic reluctance path therebetween;

means for applying a magnetic flux to each of the poles in the first and second sets to produce an elastic restraint for said element to a predetermined angular position; and

means for varying the flux in response to the signal in a first direction in the first set of poles and for varying the flux in response to the signal in an opposite direction in the second set of poles thereby to torque the element in response to the varied flux to an angular position representative of the magntiude of the signal.

8. Apparatus for providing a rotation representative of the magntidue of a signal comprising:

an element suspended for rotation and having first and second concentric arcs of high permeability material separated by a region of low permeability;

a first high permeability arcuate band of radius similar to the first arc of said element and arc length substantially greater than said first arc;

said first band placed coaxially to said element above said first arc;

said first band having a further arcuate band matching in radius the second arc of said element and positioned thereabove and coaxially thereto;

a second high permeability arcuate band of radius similar to the first arc of said element and of arc length substantially greater than said first arc;

said second band placed coaxially below said element and below said first arc;

said second band having a further arcuate band of radius similar to said second arc and positioned therebelow and coaxially thereto;

means for applying magnetic flux between said first and second arcuate bands at positions generally central thereof to indux flux to flow through said first arc and further through said second arc between the further arcuate bands;

means responsive to said signal for weakening the magnetic flux in corresponding arms of said first and second arcuate bands and for strengthening the magnetic flux in the opposite arms of said first and second arcuate bands whereby said element roates to a degree representative of the magnitude of said signal.

9. A magnetic actuator for providing a motion in response to a signal comprising:

a movable element;

a first path for magnetic flux between first and second points of application of a magnetomotive force, the first path having;

a high permeability portion on said movable element; and

a portion providing a variation in path reluctance of said first path in response to variation in the position of said movable element;

a source of magnetomotive force for applying a flux to said first path between said first and second points of application whereby said element is elastically restrained at a point of minimum reluctance in said first path;

a second path for magnetic flux between third and fourth points of application of a magnetomotive force, the second path having;

first and second portions of high permeability; and

an intermediate portion of said movable element providing a variation in the reluctance of said second path with element motion;

means for applying a magnetic flux through said second path; and

means for shifting the flux in said second path between the first and second portions of high permeability in response to said signal.

10. The actuator of claim 9 wherein the portions of high permeability in said first and second paths include press stamped bands.

11. The actuator of claim 10 wherein said element includes a rotor.

12. A magnetic actuator for providing a rotation in response to a signal comprising:

a stator having an axis and including;

first and second curved, coaxial and axially displaced bands of high permeability material, said first and second bands both extending a first angular portion of a circle;

a third curved band of high permeability material coaxial to the first and second bands and axially displaced therefrom, said third band extending a second angular portion of a circle which is less than the first portion;

a fourth curved band of high permeability material coaxial to the first and second bands and axially displaced therefrom, said fourth band extending a third angular portion of a circle which is lss than the first portion and only partially overlaps the angular extent of the third portion;

a rotor mounted for rotation coaxial to the stator and having;

a fifth high permeability band curved about said rotor and facing portions of said first and second bands over an angular extent much smaller than the first angular portion thereof;

a sixth high permeability band curved about said rotor and facing portions of the third and fourth bands to vary the magnetic reluctance between said third and fourth bands through said sixth band with rotation of said rotor, that reluctance having a minimum value at a predetermined position of angular rotation of the rotor;

means for applying a magnetic flux in a path through the sixth band between the third and fourth bands to produce an elastic restraint on the rotor at the angle of minimum reluctance;

means for applying a magnetic flux through the fifth band between the first and second bands in a pattern producing no net torque on said rotor; and

means for shifting the path of flux in the first and second bands in response to said signal to produce a net torque on said rotor.