GB2046549A - Angular position controller - Google Patents

Angular position controller Download PDF

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Publication number
GB2046549A
GB2046549A GB7908952A GB7908952A GB2046549A GB 2046549 A GB2046549 A GB 2046549A GB 7908952 A GB7908952 A GB 7908952A GB 7908952 A GB7908952 A GB 7908952A GB 2046549 A GB2046549 A GB 2046549A
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GB
United Kingdom
Prior art keywords
source
sensor
control lever
lever
radiation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB7908952A
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GB2046549B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BIDEFORD ELECTRONICS Ltd
Original Assignee
BIDEFORD ELECTRONICS Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BIDEFORD ELECTRONICS Ltd filed Critical BIDEFORD ELECTRONICS Ltd
Priority to GB7908952A priority Critical patent/GB2046549B/en
Publication of GB2046549A publication Critical patent/GB2046549A/en
Application granted granted Critical
Publication of GB2046549B publication Critical patent/GB2046549B/en
Expired legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/28—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with deflection of beams of light, e.g. for direct optical indication
    • G01D5/30—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with deflection of beams of light, e.g. for direct optical indication the beams of light being detected by photocells
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J13/00—Controls for manipulators
    • B25J13/02—Hand grip control means
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05G—CONTROL DEVICES OR SYSTEMS INSOFAR AS CHARACTERISED BY MECHANICAL FEATURES ONLY
    • G05G9/00—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously
    • G05G9/02—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously the controlling member being movable in different independent ways, movement in each individual way actuating one controlled member only
    • G05G9/04—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously the controlling member being movable in different independent ways, movement in each individual way actuating one controlled member only in which movement in two or more ways can occur simultaneously
    • G05G9/047—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously the controlling member being movable in different independent ways, movement in each individual way actuating one controlled member only in which movement in two or more ways can occur simultaneously the controlling member being movable by hand about orthogonal axes, e.g. joysticks
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05G—CONTROL DEVICES OR SYSTEMS INSOFAR AS CHARACTERISED BY MECHANICAL FEATURES ONLY
    • G05G9/00—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously
    • G05G9/02—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously the controlling member being movable in different independent ways, movement in each individual way actuating one controlled member only
    • G05G9/04—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously the controlling member being movable in different independent ways, movement in each individual way actuating one controlled member only in which movement in two or more ways can occur simultaneously
    • G05G9/047—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously the controlling member being movable in different independent ways, movement in each individual way actuating one controlled member only in which movement in two or more ways can occur simultaneously the controlling member being movable by hand about orthogonal axes, e.g. joysticks
    • G05G2009/04703—Mounting of controlling member
    • G05G2009/04722—Mounting of controlling member elastic, e.g. flexible shaft
    • G05G2009/04725—Mounting of controlling member elastic, e.g. flexible shaft with coil spring
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05G—CONTROL DEVICES OR SYSTEMS INSOFAR AS CHARACTERISED BY MECHANICAL FEATURES ONLY
    • G05G9/00—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously
    • G05G9/02—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously the controlling member being movable in different independent ways, movement in each individual way actuating one controlled member only
    • G05G9/04—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously the controlling member being movable in different independent ways, movement in each individual way actuating one controlled member only in which movement in two or more ways can occur simultaneously
    • G05G9/047—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously the controlling member being movable in different independent ways, movement in each individual way actuating one controlled member only in which movement in two or more ways can occur simultaneously the controlling member being movable by hand about orthogonal axes, e.g. joysticks
    • G05G2009/0474—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously the controlling member being movable in different independent ways, movement in each individual way actuating one controlled member only in which movement in two or more ways can occur simultaneously the controlling member being movable by hand about orthogonal axes, e.g. joysticks characterised by means converting mechanical movement into electric signals
    • G05G2009/04759—Light-sensitive detector, e.g. photoelectric

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Robotics (AREA)
  • Mechanical Engineering (AREA)
  • Switches With Compound Operations (AREA)

Abstract

An angular position controller, for use, for example, in controlling an invalid's wheel chair, has a movable "joystick" control lever (1) supported on a spring (13) for universal movement. The lever carries a diffusely reflective plate (7) which cooperates with two fixed infra-red source/sensor assemblies (16) so positioned that the radiation path length between each source and its associated sensor depends upon the inclination of the reflective plate (7) into mutually perpendicular planes, so that the electrical outputs of the two sensors can be used to give an indication of the angular position of the control lever (1). <IMAGE>

Description

SPECIFICATION Angular position controller The present invention relates to an angular position controller of the type in which angular movements of a manual control lever or "joystick" produce electrical output signals corresponding to the angular movements. Such angular position controllers find numerous practical applications, for example, in the servo-control of power operated vehicles such as wheel chairs or invalid carriages or in the control of adjustable platforms or remote handling devices.
It is known to provide electrical output signals from angular position controller of the joystick type by employing potentiometric elements coupled to an angularly displaceable control lever. Normally in such an arrangement the control lever is mounted universally so that angular displacement of the lever in two mutually perpendicular planes causes rotation of the shafts of two potentiometers arranged with their shaft axes mutually perpendicular to each other. Such arrangements necessitate a precision mechanical mounting of the control lever and its associated potentiometers. Moreover, the electrical output signals derived from potentiometers can be erratic, particularly if the potentiometers become contaminated with dust or dirt, added to which the potentiometers, being essentially electromechanical, are prone to wear over extensive periods of use.
An object of the present invention is to provide an improved angular position controller in which electrical output signals are derived from angular displacements of a control lever without any mechanical moving parts in the derivation of electrical signals as such.
According to the invention there is provided an angular position controller comprising an angularly displaceable manual control lever, a source of radiation, a sensor arranged to pick-up radiation from the source after it has traversed an air space, an angularly displaceable member carried by the control lever and so arranged that the length of the radiation path between the source and the sensor is changed upon angular displacement of the lever in at least one plane of rotation, resulting in a corresponding change in the output of the sensor.
In one embodiment of the invention the displaceable member carries the source or sensor, the sensor or the source respectively being fixed. Angular displacements of the lever result in a change in the distance between the source and the sensor and, therefore, in the attenuation of the radiation traversing the air space between the source and the sensor.
In a preferred practical embodiment of the invention the displaceable member has a diffusively reflective surface facing towards the source, the sensor and source being fixed and arranged so that the radiation from the source impinges on the sensor after reflection from the said reflective surface. Preferably an infra-red source and sensor are arranged side-by-side in a common housing. For example, a combined infra-red emitter/sensor may be used, of the comercially available type number IPL 101 to made by Integrated Photomatrix Limited.With this arrangement the infra-red radiation traverses the air gap between the source and the reflective surface twice before impinging upon the sensor, so that the arrangement is inherently more sensitive to changes in the relative position of the reflective surface and the source/sensor assembly resulting from angular displacement of the control lever.
It is a simple matter to render the controller responsive to angular displacements of the lever in more than one plane by simply providing two or more source/sensor pairs associated with a common angularly displaceable member, the sensors being positioned so as to be responsive to angular displacement of the lever in different respective planes.
In a preferred practical construction the or each source/sensor assembly is housed in a light-tight enclosure. The angularly displaceable lever may be supported by a wall of the enclosure, the displaceable member carried by the control lever being housed within the enclosure. In this case the lever would normally be surmounted by a manually operable elment such as a knob externally of the enclosure, the lever itself being surrounded by a flexible light-tight boot of rubber or like material to permit the angular displacement of the lever.
In a preferred practical embodiment the manually displaceable control lever is supported from a fixed support by means of a helical spring which permits angular displacement of the control lever in any direction from a rest position in which the spring is undeflected. One end of the helical spring may be anchored in the fixed support and the other end anchored in a boss attached to one end of the control lever, the boss supporting the angularly displaceable member within the light-tight enclosure. The other end of the control lever may carry a control knob, the lever itself being freely rotatable relative to the boss so that rotation of the knob does not result in any rotation of the displaceable member about the longitudinal axis of the lever.
An embodiment of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which: Figure lisa sectional view of an angular position controller according to one embodiment of the invention; Figure 2 is a cross-sectional view taken on line ll-ll in Figure 1; Figure 3 is an exploded perspective view of the controller shown in Figures 1 and 2 and, Figure 4 is an electrical circuit associated with one infra-red source/sensor pair in the controller of Figures 1 to 3.
The illustrated angular position controller has an angularly displaceable manual control lever 1 carrying a control knob 2 at one end and connected at its other end to a metal boss 3. The metal boss 3 has a central throughbore 4 which is counter-bored to define an internal shoulder 5. The control lever 1 is rotatably supported within the bore 4 for rotation about its axis, the end of the lever within the counter-bore being provided with an enlarged head 6 which abuts the internal annular shoulder 5, anchoring the lever 1 to the boss 3 while permitting rotation of the lever about its longitudinal axis relative to the boss 3.
A flat square metal plate 7 is attached centrally to the boss 3 and is perpendicular to the axis of the control lever 1, being anchored to the boss 3 by a nut 8 which is threaded onto an externally screwthreaded collar formed at the end of the boss 3 opposite that through which the lever 1 projects.
The boss 3 and the control lever 1 connected thereto is supported from a central support member 9 which is anchored by means of a fixing screw 10 to a base plate 11. The base plate 11 is in turn supported in a housing 12 by means of a metal mounting bracket (Figure 3). The supporting connection between the support member 9 and the boss 3 takes the form of a closely wound helical spring 13 which is anchored at one end, its lower end, as illustrated in Figure 1, in the support member 9, coaxially surrounding the fixing screw 10, and is anchored at its other end, the upper end as shown in Figure 1, in the counter-bore of the boss 3, in which the spring 13 coaxiallysurrounds a cylindrical insert 14 having an enlarged head 15 which abuts the head 6 of the control lever 1.The anchoring of the opposite ends of the helical spring 13 in the boss 3 and the support member 9 is effected by respective grub screws, 16, 17.
In the rest or undeflected condition of the helical support spring 13 the plate 7 is disposed substantially parallel to the base plate 11, as shown in Figure 1. The plate 7 is provided on its under surface, that is its surface facing towards the base plate 11, with a diffusively reflective coating, for example, a matt white coating.
Two infra-red source/sensor assemblies, 16, 17 are mounted on the base plate 11 on one side of the central support member 9. Each source/sensor assembly 16, 17 comprises a combined emitter/sen sorofthetype IPL 101RC manufactured by Integrated Photomatrix Limited and consisting of a photo diode infra-red emitter 16A, 17A mounted in a common housing alongside a photo-transistor infra-red sensor 17B, 16B, both the source/sensor pairs having coplanar emitting/sensing surfaces disposed parallel to the base plate 11 and facing towards the diffusively reflective surface of the plate 7.
The two source/sensor assemblies 16, 17 are mounted on a common printed circuit board 18 which is supported from the base plate 11 and which carries printed circuit elements associated with the two source/ sensor assemblies.
The control lever 1 projects a circular aperture in an upperwall 12Aofthe housing 12. Astop plate 19 is secured to the underside of the upper wall 1 2A by fixing bolts 20, the stop plate 19 having a circular aperture with a bevelled edge 21 which defines the limits of angular displacement of the control lever 1 from its "neutral" or rest position. A collar 22 is freely rotatable upon the control lever 1 and is trapped between the boss 3 and a sleeve 23 interposed between the collar 22 and the knob 2. The collar 22 comes into contact with the bevelled edge 21 of the stop plate 19 in the extreme position of permitted angular displacement of the lever 1, any circumferential displacement of the lever 1 in such extreme positions being accompanied by rolling of the collar 22 on the bevelled edge 21.
Two of the extreme positions of the axis of the control lever 1 are shown in broken outline in Figure 1, and it will be seen that in this example the total angular range of permitted movement of the control lever 1 in any direction is about 15 from the neutral position.
A light-tight enclosure 24 is attached to the stop plate 19 and encloses the base plate 11 and the components of the controller between the stop plate 19 and the base plate 11, including the two source/sensor assemblies 16,17. The entry of extraneous light into the enclosure 24 through the aperture in the stop plate 19 is prevented by a rubber boot 25 which is sealed against the external surface of the sleeve 23 immediately adjoining the knob 2 and which is clamped peripherally. between the stop plate 19 and the upper wall 1 2A by the bolts 20.
In operation of the controller the infra-red sources 1 6A, 1 7A of the two source/sensor assemblies 16, 17 are connected to a stabilized supply so that each emits infra-red radiation of a constant intensity. The infra-red radiation is transmitted through the air space between the source/sensor assemblies 16, 17 and the reflective underside of the plate 7, where the radiation is diffusively reflected, the reflected infrared radiation being picked up by the respective sensors 16B, 17B. The attenuation of the infra-red radiation in twice traversing the air space between the assemblies 16, 17 and the plate 7 will be proportional to the distance between the respective assemblies 16, 17 and those parts of the plate 7 which are "illuminated" by them.This distance will in turn be dependent upon the angular displacement of the plate 7 and therefore, of the control lever 1. The electrical output signals from the photoelectric sensors 16B, 17B will consequently provide an indication of the angular displacement of the plate 7 from its "neutral" position in which the plate 7 is parallel to the base plate 11.
In a typical practical embodiment the size of the air gap between the source/sensor assemblies 16, 17 and the reflective surface of the plate 7 in the "neutral" position of the control lever 1 would typically be about 10 mm. Movement of the control lever 1 to the left of the neutral position in which it is shown into engagement with the stop plate edge 21 would reduce the size of this gap to approximately 5 mm, producing a proportionate increase in the output current signal of the photoelectric sensors 16B, 17B. Conversely, movement of the control lever 1 in the opposite direction against the stop plate edge 21, to the right as shown in Figure 1, would increase the size of the gap to approximately 15 mm, causing a proportionate decrease in the output current signals of the photoelectric sensors 16B,17B. Movement of the control lever 1 with components in a plane per pendicularto the plane of Figure 1 would give rise to a difference in the sizes of the air gaps between the respective sensor assemblies 16, 17 and the plate 7.
It is therefore possible by means of the two source/sensor assemblies 16, 17 to resolve the angular displacement of the control lever 1 in any direction into two electrical output signals.
Electrical supplies to and signals from the circuit associated with the source/sensor assemblies are passed through a cable (not shown) which passes sealingly through a rubber gromet 26 in one wall of the enclosure 24.
The electrical circuit associated with one of the source/sensor assemblies, 16, is shown diagrammatically in Figure 4, a corresponding circuit being provided for the other source/sensor assembly 17. A potentionmeter VR1, resistors R2, R3, and the transistor TR1 together constitute a constant current supply circuit which is connected to a stabilized DC supply 27 and which supplies a constant current to the associated infra-red source 16A, comprising a light emitting diode. The radiation output intensity may be preset by adjustment of the potentiometer VR1.
The associated infra-red radiation sensor 16B comprises a phototransistor connected across the stabilized power supply through a potentiometer VR2 and resistor R4. The potentiometer VR2 is set so that when the control lever 1 is in the neutral position the voltage dropped across VR2 and R4 is equal to the positive supply voltage with respect to the zero volt line, so that the output signal derived from the collector of the phototransistor is zero.Movement of the control lever in one direction will cause the collector/emitter current of the phototransistor sensor 16B to increase, causing the output signal to become negative with respect to the zero volt line, while movement of the control lever in the reverse direction will cause a reduction in the collector/emitter current of the phototransistor sensor 16B, resulting in a positive output voltage with respect to the zero volt line. Both the amplitude and direction of movement of the control lever 1 is therefore resolved by each infra-red sensing circuit.
Inan alternative embodiment of the invention four infra-red sensors, rather than two, may be employed, the infra-red sources being supplied with a cyclically changing signal to cause corresponding variations in the output signals of the respective sensors. The sensor output voltages may be compared in a differential amplifier with a reference signal to derive a difference signal which will be dependent upon the angular displacement of the control lever 1, the phase of the difference signal being indicative of the direction of displacement of the control lever.
It will be appreciated that various materials may be employed in the manufacture of the controller.
For example, the angularly displaceable plate 7 may be made of metal or plastics material, and similarly the light-tight housing 24 may be of metal or plastics material. Instead of the helical spring 13 other resiliently flexible support means may be employed for supporting the control lever 1 from a fixed mounting: for example, a solid rubber block may be employed.

Claims (1)

1. An angular position controller comprising an angularly displaceable manual control lever, a source of radiation, a sensor arranged to pick-up radiation from the source after it has traversed an air space, and an angularly displaceable member carried by the control lever and so arranged that the length of the radiation path between the source and the sensor is changed upon angular displacement of the lever in at least one plane of rotation, resulting in a corresponding change in the output of the sensor.
2. A controller as claimed in Claim 1, in which the displaceable member carries the source of the sensor, the sensor or the source respectively being fixed.
3. A controller according to Claim 1, in which the displaceable member has a diffusively reflective surface facing towards the source, the sensor and source being fixed and arranged so that infra-red radiation from the source impinges on the sensor after reflection from the said reflective surface.
4. A controller according to Claim 3, in which the source and the sensor are arranged side-by-side in a common housing.
5. A controller according to any one of the preceding claims in which there are two or more source-sensor pairs and a common angularly displaceable member, the sensors being responsive to angular displacement of the lever in different respective planes.
6. An angular position controller substantially as herein described with reference to and as shown in the accompanying drawings.
New claims or amendments to claims filed on 16.5.80 Superseded claims 1 New or amended claims
1. An angular position controller comprising an angularly displaceable manual control lever, a source of radiation, a sensor arranged to pick-up radiation from the source after it has traversed an air space, an angularly displaceable member movable by the control lever and so arranged that the length of the radiation path between the source and the sensor is changed upon angular displacement of the lever in at least one plane of rotation, resulting in a corresponding change in the output of the sensor, and a resiliently flexible element supporting the angularly displaceable member from a fixed support to permit universal angular displacement of said member by the control lever.
GB7908952A 1979-03-14 1979-03-14 Angular position controller Expired GB2046549B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB7908952A GB2046549B (en) 1979-03-14 1979-03-14 Angular position controller

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB7908952A GB2046549B (en) 1979-03-14 1979-03-14 Angular position controller

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GB2046549A true GB2046549A (en) 1980-11-12
GB2046549B GB2046549B (en) 1983-10-19

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2125947A (en) * 1982-08-30 1984-03-14 Suncom Inc Joy stick
FR2575845A1 (en) * 1985-01-07 1986-07-11 Saf Chainette Control manipulator resistant to shocks
ES2078853A2 (en) * 1993-05-06 1995-12-16 Univ Cordoba Mouth-operated pointer for computer.
GB2366924A (en) * 2000-09-13 2002-03-20 Unique Product & Design Co Ltd Electric carrier with a motor controlled by a relative positional mechanism

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2125947A (en) * 1982-08-30 1984-03-14 Suncom Inc Joy stick
FR2575845A1 (en) * 1985-01-07 1986-07-11 Saf Chainette Control manipulator resistant to shocks
ES2078853A2 (en) * 1993-05-06 1995-12-16 Univ Cordoba Mouth-operated pointer for computer.
GB2366924A (en) * 2000-09-13 2002-03-20 Unique Product & Design Co Ltd Electric carrier with a motor controlled by a relative positional mechanism
GB2366924B (en) * 2000-09-13 2002-09-18 Unique Product & Design Co Ltd Electric carrier with a motor controlled by a relative positional mechanism

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Publication number Publication date
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