WO2016137404A1 - Appareil à suspension à cardan pour caméra aérienne et son procédé associé - Google Patents

Appareil à suspension à cardan pour caméra aérienne et son procédé associé Download PDF

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Publication number
WO2016137404A1
WO2016137404A1 PCT/TH2015/000011 TH2015000011W WO2016137404A1 WO 2016137404 A1 WO2016137404 A1 WO 2016137404A1 TH 2015000011 W TH2015000011 W TH 2015000011W WO 2016137404 A1 WO2016137404 A1 WO 2016137404A1
Authority
WO
WIPO (PCT)
Prior art keywords
camera
magnet
azimuth
mounting frame
tilt
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.)
Ceased
Application number
PCT/TH2015/000011
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English (en)
Inventor
Prasatporn WONGKAMCHANG
Wuttichai METTANON
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Priority to PCT/TH2015/000011 priority Critical patent/WO2016137404A1/fr
Publication of WO2016137404A1 publication Critical patent/WO2016137404A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C11/00—Photogrammetry or videogrammetry, e.g. stereogrammetry; Photographic surveying

Definitions

  • the present disclosure relates to aerial cameras and more particularly to an aerial camera gimbal apparatus for reducing imaging errors caused by aircraft vibrations on the line of sight of an aerial camera.
  • an aerial camera gimbal can be set up on the aircraft structure and the motion of the camera can be controlled remotely from a ground station as well as from the airplane.
  • This arrangement allows the camera gimbal to send tremulous pictures to the ground by using a long-range data communication system.
  • Such an arrangement is very convenient for a variety of survey applications.
  • the camera gimbal includes two important parts. The first part is a gimbal mechanism with camera and sensor installed at the centre of the gimbal mechanism. The other part is an image processing / programming part which stabilizes the images. Since a moving platform such as an aircraft induces acceleration, frictional forces and forces due to mass imbalance, effects known as disturbances to the input must be suppressed.
  • Motion control of the camera gimbal can be divided into two parts.
  • the first part is controlled by a feedback control system in order to move the gimbal according to a reference command, and at the same time stabilize the gimbal where the camera is attached. Jitter reduction is also required to be considered in the motion controller.
  • the second part is the stabilizing of images conducted by an image processing / programming technique.
  • an object of the non-limiting exemplary embodiments to provide an aerial camera gimbal system, apparatus, device, and/or technique.
  • the non-limiting embodiments of this disclosure satisfy the need indicated in the background by providing an aerial camera gimbal apparatus utilizing a camera mounting frame incorporating a magnetizing mechanism to reduce errors caused by vibrations from an aircraft on the line of sight of an aerial camera.
  • This and other objects, features, and advantages of the invention are provided by the aerial camera gimbal system for reducing the errors caused by the vibrations from the aircraft on the line of sight of the camera.
  • an apparatus for reducing effects of vibrations on a line of sight of an aerial camera.
  • the apparatus comprises a magnet mounting arranged at a vertical mid-plane of a camera mounting frame, the magnet mounting having a first magnet fixedly mated thereon; an attachment structure fixedly mated to the camera mounting frame; and a second magnet fixedly mated to the attachment structure.
  • the first magnet and the second magnet are in a proximal non-contact magnetizing relationship with each other.
  • a centre of gravity of the camera mounting frame when mounted with a camera thereon is situated at an intersection of a tilt axis provided by an inner joint and an azimuth axis provided by an outer joint of a two-axis gimbal system.
  • the gimbal system comprises a control system for maintaining the line of sight of the camera to within an angular measurement error of less than two degrees.
  • the gimbal system further comprises a base on which the outer joint is rotatably mounted, and wherein the base is adapted to be attached to a predetermined portion of an aircraft structure.
  • the outer joint comprises: a base plate rotatably mated to the base; a pair of outer frames extending from opposed sides of the base plate; mounting mechanism located on each of the pair of outer frames from which the inner joint is rotatably mated; a first tooth ring centrally mounted at a lower face of the base plate; and a second tooth ring mated to one of the outer frames, wherein a centre of the second tooth ring and centre points of the mounting mechanism define the tilt axis of the gimbal system.
  • the inner joint comprises: a pair of upper and lower arcuate sections; and a pair of planar sections having a centrally located aperture for attachment of the mounting mechanism, wherein a centre of the first tooth ring and centre points of the upper and lower arcuate sections of the inner joint define the azimuth axis of the gimbal system.
  • the camera mounting frame comprises: a camera holder having an upper portion in sliding engagement with a top end portion of the camera mounting frame; and a locking latch for detachably locking the camera to the camera mounting frame.
  • the control system comprises: a tilt controller for controlling a tilt motor for maintaining an elevation line of sight of the camera; an azimuth controller for controlling an azimuth motor for maintaining an azimuth line of sight of the camera; a tilt sensor mounted at an end portion of the tilt motor for detecting a tilt angle of the gimbal system; and an azimuth sensor mounted at an end portion of the azimuth motor for detecting an azimuth angle of the gimbal system.
  • the azimuth motor is mounted on the base; and wherein the azimuth motor is communicatively mated to the first tooth ring by a first belt for controlled movement of the outer joint.
  • the tilt motor is mounted on the base plate of the outer joint; and wherein the tilt motor is communicatively mated to the second tooth ring by a second belt for controlled movement of the inner joint.
  • a system for reducing effects of vibrations on a line of sight of an aerial camera comprises a magnet mounting arranged at a vertical mid-plane of a camera mounting frame, the magnet mounting having a first magnet fixedly mated thereon; an attachment structure fixedly mated to the camera mounting frame; and a second magnet fixedly mated to the attachment structure.
  • the first magnet and the second magnet are in a proximal non- contact magnetizing relationship with each other.
  • a centre of gravity of the camera mounting frame when mounted with a camera thereon is situated at an intersection of a tilt axis provided by an inner joint and an azimuth axis provided by an outer joint of a two-axis gimbal system.
  • a method of reducing effects of vibrations on a line of sight of an aerial camera may include the steps of: arranging a magnet mounting at a vertical mid-plane of a camera mounting frame; fixedly mating a first magnet to the magnet mounting; providing an attachment structure to the camera mounting frame; and fixedly mating a second magnet to the attachment structure.
  • the first magnet and the second magnet are in a proximal non-contact magnetizing relationship with each other.
  • a centre of gravity of the camera mounting frame when mounted with a camera thereon is situated at an intersection of a tilt axis provided by an inner joint and an azimuth axis provided by an outer joint of a two-axis gimbal system.
  • the method may further comprise the steps of: providing the gimbal system with a control system for maintaining the line of sight of the camera to within an angular measurement error of less than two degrees; mounting the camera to the camera mounting frame with a camera holder having an upper portion in sliding engagement with a top end portion of the camera mounting frame; and providing a locking latch for detachably locking the camera to the camera mounting frame.
  • the combination of the claimed features of this invention provides a novel way of enabling the line of sight of an aerial camera to be maintained to within an angular measurement error of less than two degrees when utilized on an aircraft as described.
  • FIG. 1 is a perspective view showing a rear side of the aerial camera gimbal system, in accordance with the non-limiting exemplary embodiments;
  • FIG. 1 a is a representational view of the apparatus when mounted on an aircraft
  • FIG, 2 is a perspective view showing a front side of the apparatus, in accordance with the non-limiting exemplary embodiments
  • FIG. 3 is a side elevational view of the apparatus as shown in FIG. 1 ;
  • FIG. 4 is a perspective view of the outer joint;
  • FIG. 5 is a perspective view showing the inner and outer joints
  • FIG. 6 is an exploded view showing the inner joint, mounting assembly and the camera mounting frame
  • FIG. 7 is a perspective view showing the assembling of camera to the camera mounting frame.
  • FIG. 8 is a schematic block diagram showing the configuration of the aerial camera gimbal system.
  • Embodiments of this disclosure relate to an aerial camera gimbal sytsem, apparatus, structure, and/or device.
  • the apparatus provides a means for reducing errors caused by vibrations transmitted from an aircraft carrying the aerial gimbal apparatus and an aerial camera associated therewith on the line of sight of the aerial camera.
  • the aerial camera gimbal apparatus 10 may include a magnet mounting 12 arranged at a vertical mid-plane 90 of a camera mounting frame 14.
  • a first magnet 16 may be fixedly mated onto the magnet mounting 12.
  • An attachment structure 18 may further be fixedly mated to the top rear portion of the inner joint 24.
  • a second magnet 22 may be fixedly mated to the attachment structure 18. The arrangement is such that the first magnet 16 and the second magnet 22 are in a proximal non-contact relationship with each other to provide a magnetizing effect on each other.
  • the camera mounting frame 14 when mounted with a camera 40 may further be arranged such that the centre of gravity of the assembly is situated at an intersection x of a tilt axis 91 provided by an inner joint 24 and an azimuth axis 92 provided by an outer joint 26 of a two-axis gimbal system 60.
  • the camera 40 is mounted on the camera mounting frame 14 which is in turn mounted along the tilt axis 91 of the inner joint 24.
  • the camera mounting frame 14 can move freely in two degrees of freedom within a limited small angle. In this way, the camera mounting frame 14 and the camera 40 are kept at a centre position by the magnetic field created by the first magnet 16 and the second magnet 22, such that vibrations may be damped out effectively.
  • the apparatus 10 may include a base 28 on which the outer joint 26 is rotatably mounted.
  • the base 28 may be suitably constructed to be attached to a predetermined portion of an aircraft structure 30.
  • FIG. la shows a mounting orientation of the apparatus 10, showing the tilt angle z at 0° to 70°.
  • Such an angular tilt range is best for the camera 40 to be held within the measurement error of less than 1 degree.
  • the tilt angle z can vary between -10° to 1 10° and the azimuth angle can rotate 360° in other configurations. From these ranges, the first magnet 16 and the second magnet 22 can efficiently diminish the errors caused by the vibrations.
  • the mechanical balancing can be achieved by designing a symmetrical structure for the camera mounting frame 14 and inner joint 24.
  • Dynamic balancing can next be tested by using for example an external motor (not shown) for rotating the inner joint 24 and then using a dynamic balancing machine (not shown) to measure any deviated centrifugal force and adjustments made accordingly.
  • the outer joint 26 may include a base plate 32 rotatably mounted to the base 28.
  • a pair of arch-shaped outer frames 34 may extend from opposed sides of the base plate 32.
  • a mounting mechanism 36 may further be located on each of the pair of outer frames 34 from which the inner joint 24 may be rotatably mounted.
  • a first tooth ring 38 may be centrally mounted at a lower face of the base plate 32 as shown in FIG. 4.
  • the inner joint 24 may include a pair of upper and lower arcuate sections 42 and a pair of planar sections 44. Each of the pair of planar sections 44 may include a centrally located aperture 46 for attachment of the mounting mechanism 36.
  • the azimuth axis 92 may further pass through the centre of the first tooth ring 38 and the centre points of the pair of upper and lower arcuate sections 42 of the inner joint 24.
  • a second tooth ring 48 may be mounted to the inner joint 24. This second tooth ring 48 may be located next to an inner side of the outer frames 34 of one of the outer joint 26 to facilitate controlled movement of the inner joint 24.
  • the centre of the second tooth ring 48 and centre points of the mounting mechanism 36 provide the tilt axis 91 of the gimbal system 60.
  • the mounting mechanism 36 may include a pair of bearing 49 and bush 54 assembled to provide a low friction rotational movement of the inner joint 24.
  • the apparatus 10 may include a control system 50 for maintaining the line of sight 93 of the camera 40 to within an angular measurement error of less than two degrees.
  • a control system 50 may include a tilt controller 52 for controlling a tilt motor 64 for maintaining the elevation line of sight of the camera 40.
  • the control system 50 may further include an azimuth controller 53 for controlling an azimuth motor 56 for maintaining the azimuth line of sight of the camera 40.
  • a tilt sensor 53a may be mounted at an end portion of the tilt motor 64 for detecting the tilt angle of the gimbal system 60 and an azimuth sensor 53b may be mounted at an end portion of the azimuth motor 56 for detecting the azimuth angle of the gimbal system 60.
  • the azimuth motor 56 may be mounted on the base plate 32 and may be engaged to the first tooth ring 38 by a first belt 58 for controlled movement of the outer joint 26. It is envisaged that the azimuth motor 56 may include a pinion gear 62 for engaging the first belt 58 which is in turn engaged to the first tooth ring 38. As best shown in FIGS. 3 and 5, the tilt motor 64 may be mounted on the base plate 32 for controlled movement of the inner joint 24. The tilt motor 64 may be communicatively mated to the second tooth ring by a second belt 66. It is envisaged that the tilt motor 64 may also include a pinion gear (not shown) for engaging the second belt 66 which is in turn engaged to the second tooth ring 48.
  • the camera mounting frame 14 may include a camera holder 68 having an upper portion in sliding engagement with a top end portion of the camera mounting frame 14.
  • a locking latch 72 may be located at the top end portion of the camera mounting frame 14 for detachably locking the camera 40 to the camera mounting frame 14.
  • the attachment structure 18 for the second magnet 22 is a back cover for the camera 40.
  • the proximal non-contact distance y between the first magnet 16 and the second magnet 22 may range between 8 and 10 millimetres, preferably 9 millimetres.
  • the position of the first magnet 16 and the second magnet 22 advantageously maintains the line of sight 93 of the camera 40 to within an angular measurement error of less than one degree.
  • the back cover 18 shown is a convenient structure whereon the second magnet 22 may be affixed, it should be appreciated that any structure capable of holding the second magnet 22 in the position aforementioned may be utilized.
  • the first magnet 16 and the second magnet 22 may include high strength rear earth magnets capable of holding the camera 40 as described.
  • the configuration of the apparatus 10 for reducing the line of sight errors is best shown in FIG. 8.
  • the control system 50 may include the tilt controller 52 and the azimuth controller 53 which may be proportional-integral-derivative (PID) controllers.
  • the tilt controller 52 and the azimuth controller 53 may further be of an advanced controller design for an inertial stabilization system for controlling a 2-DOF (2 degrees-of-freedom) gimbal which can be mounted to an aircraft structure 30.
  • An advanced controller is desired in view of the dynamics modelling errors, friction and disturbances from the outside environment which can severely degrade the tracking accuracy of an airborne gimbal.
  • a robust inverse dynamics control and adaptive control may be utilized in an inner loop or gimbal servo- system to control the gimbal motion.
  • Indirect line of sight (LOS) stabilization may be controlled by the outer loop controller.
  • a sensor (not shown) may be utilized to measure a base rate and orientation of the gimbal system 60 with reference to a fixed reference frame.
  • a reference LOS input 93a is shown.
  • This reference LOS input 93a may be a command provided by the user to aim the camera 40 in a certain direction.
  • the control system 50 may next point the camera 40 at the commanded direction, thus providing a line of sight (LOS) output 93.
  • the accuracy of the line of sight 93 is improved by the holding power of the first magnet 16 and the second magnet 22, such that the LOS 93 is held to within an error of one degree of the reference LOS input 93 a.
  • the first magnet 16 may be mounted on the camera mounting frame 14 by means of the magnet mounting 12 while the second magnet 22 may be mounted on the attachment structure 18. It is envisaged that one skilled in the art will be able to design the magnet mounting 12 and the attachment structure 18 in such a manner that the first magnet 16 and the second magnet 22 are positioned at between 8 and 10 millimetres of each other.
  • the invention may include a method of reducing the effects of vibrations on the line of sight 93 of an aerial camera 40.
  • Such a method may include the steps of: arranging a magnet mounting 12 at a vertical mid-plane 90 of a camera mounting frame 14; fixedly mating a first magnet 16 to the magnet mounting 12; providing an attachment structure 18 to the camera mounting frame 14; and fixedly mating a second magnet 22 to the attachment structure 18.
  • the first magnet 16 and the second magnet 22 are in a proximal non-contact magnetizing relationship with each other.
  • the centre of gravity of the camera mounting frame 14 when mounted with a camera 40 thereon is situated at an intersection x of a tilt axis 91 provided by an inner joint 24 and an azimuth axis 92 provided by an outer joint 26 of a two-axis gimbal system 60.
  • the method may further include the steps of: providing the gimbal system 60 with a control system 50 for maintaining the line of sight 93 of the camera 40 to within an angular measurement error of less than two degrees; adjusting the proximal non-contact distance y between the first magnet 16 and the second magnet 22 to between 8 and 10 millimetres, preferably 9 millimetres, for maintaining the line of sight 93 of the camera 40 to within an angular measurement error of less than one degree; mounting the camera 40 to the camera mounting frame 14 with a camera holder 68 having an upper portion in sliding engagement with the top end portion of the camera mounting frame 14; and providing a locking latch 72 for detachably locking the camera 40 to the camera mounting frame 14.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Accessories Of Cameras (AREA)

Abstract

L'invention concerne un appareil à suspension à cardan pour caméra aérienne qui peut comprendre un montage d'aimant disposé dans un plan médian vertical d'un cadre de montage de caméra. Un premier aimant peut être accouplé de manière fixe sur le montage d'aimant. Une structure de fixation peut être accouplée de manière fixe à la partie arrière de l'articulation interne. Un second aimant peut être accouplé à la structure de fixation. Le premier aimant et le second aimant sont positionnés dans une relation sans contact proximale l'un avec l'autre pour fournir un effet de magnétisation l'un sur l'autre. Le cadre de montage de caméra, lorsque ce dernier est équipé d'une caméra, est agencé de telle sorte que le centre de gravité de l'ensemble est situé à une intersection d'un axe d'inclinaison fourni par une articulation interne et un axe d'azimut fourni par une articulation externe d'un système de suspension à cardan à deux axes. L'appareil réduit les erreurs provoquées par des vibrations provenant d'un aéronef sur la ligne de visée de la caméra aérienne.
PCT/TH2015/000011 2015-02-26 2015-02-26 Appareil à suspension à cardan pour caméra aérienne et son procédé associé Ceased WO2016137404A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/TH2015/000011 WO2016137404A1 (fr) 2015-02-26 2015-02-26 Appareil à suspension à cardan pour caméra aérienne et son procédé associé

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/TH2015/000011 WO2016137404A1 (fr) 2015-02-26 2015-02-26 Appareil à suspension à cardan pour caméra aérienne et son procédé associé

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WO2016137404A1 true WO2016137404A1 (fr) 2016-09-01

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107643156A (zh) * 2017-10-30 2018-01-30 长春工业大学 三轴转动振动台
CN111594723A (zh) * 2020-05-20 2020-08-28 深圳市莫孚康技术有限公司 摄像机稳定装置及控制方法
CN113669563A (zh) * 2020-04-30 2021-11-19 新思考电机有限公司 两轴倾斜装置、照相装置以及电子设备

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5897223A (en) * 1997-11-17 1999-04-27 Wescam Inc. Stabilized platform system for camera
US20100019120A1 (en) * 2004-12-13 2010-01-28 Optical Alchemy, Inc. Multiple axis gimbal employing nested spherical shells
US20120263445A1 (en) * 2011-04-13 2012-10-18 Beasley Ronald L Device for supporting a camera in a helicopter
US8559802B1 (en) * 2012-05-25 2013-10-15 Google Inc. System and method for isolating camera movement

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5897223A (en) * 1997-11-17 1999-04-27 Wescam Inc. Stabilized platform system for camera
US20100019120A1 (en) * 2004-12-13 2010-01-28 Optical Alchemy, Inc. Multiple axis gimbal employing nested spherical shells
US20120263445A1 (en) * 2011-04-13 2012-10-18 Beasley Ronald L Device for supporting a camera in a helicopter
US8559802B1 (en) * 2012-05-25 2013-10-15 Google Inc. System and method for isolating camera movement

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107643156A (zh) * 2017-10-30 2018-01-30 长春工业大学 三轴转动振动台
CN113669563A (zh) * 2020-04-30 2021-11-19 新思考电机有限公司 两轴倾斜装置、照相装置以及电子设备
CN111594723A (zh) * 2020-05-20 2020-08-28 深圳市莫孚康技术有限公司 摄像机稳定装置及控制方法
CN111594723B (zh) * 2020-05-20 2025-05-06 深圳市莫孚康技术有限公司 摄像机稳定装置及控制方法

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