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WO2018214162A1 - Caméra d'action - Google Patents

Caméra d'action Download PDF

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Publication number
WO2018214162A1
WO2018214162A1 PCT/CN2017/086171 CN2017086171W WO2018214162A1 WO 2018214162 A1 WO2018214162 A1 WO 2018214162A1 CN 2017086171 W CN2017086171 W CN 2017086171W WO 2018214162 A1 WO2018214162 A1 WO 2018214162A1
Authority
WO
WIPO (PCT)
Prior art keywords
camera
driving member
axis
rotating
motion
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/CN2017/086171
Other languages
English (en)
Chinese (zh)
Inventor
廖然
马天航
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.)
SZ DJI Technology Co Ltd
Original Assignee
SZ DJI Technology Co 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 SZ DJI Technology Co Ltd filed Critical SZ DJI Technology Co Ltd
Priority to PCT/CN2017/086171 priority Critical patent/WO2018214162A1/fr
Priority to CN201780065700.0A priority patent/CN109863086A/zh
Publication of WO2018214162A1 publication Critical patent/WO2018214162A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D47/00—Equipment not otherwise provided for
    • B64D47/08—Arrangements of cameras

Definitions

  • the present invention relates to a camera, and more particularly to a motion camera.
  • the traditional sports camera does not have a mechanical stabilization function, and the quality of pictures or videos taken under severe motion is not high.
  • the existing solution is to externally connect the camera to the pan/tilt and mount the pan/tilt on a movable device such as a drone.
  • a movable device such as a drone.
  • a motion camera includes a housing and a camera, the motion camera further comprising a pan/tilt mechanism at least partially disposed in the housing, the camera being disposed on the pan/tilt mechanism and capable of being stabilized by the pan/tilt mechanism Shoot and/or adjust the angle of the shot.
  • the above-mentioned motion camera separately sets the pan-tilt mechanism and the camera in the outer casing of the motion camera to prevent the pan-tilt mechanism and the camera from being shaken by external factors, thereby realizing the stabilization of the sports camera. effect.
  • the gimbal mechanism and the camera are respectively disposed in the outer casing of the motion camera, which can further reduce the overall volume of the motion camera and improve the portability of the motion camera.
  • FIG. 1 is a perspective view of a motion camera according to a first embodiment of the present invention.
  • FIG. 2 is a perspective view of the motion camera shown in FIG. 1 with the housing omitted.
  • FIG 3 is a perspective view of the motion camera of the second embodiment of the present invention with the outer casing omitted.
  • FIG. 4 is a perspective view of the pan/tilt mechanism and the camera of the motion camera shown in FIG. 3.
  • Fig. 5 is a cross-sectional view of the pan/tilt mechanism and the camera shown in Fig. 4 taken along line V-V.
  • Fig. 6 is a cross-sectional view of the pan/tilt mechanism and the camera shown in Fig. 4 taken along line VI-VI.
  • Sports camera 100 200 shell 110 case 111 Windows 112 Containment chamber 113 support 120, 220 power supply 130, 230 Yuntai organization 150, 250 First rotary drive 151 First turret 152, 252 Second rotary drive 153 Second turret 154, 253 Third rotary drive 155 camera 160, 260 Board unit 170,270 First circuit board unit 171 Second circuit board unit 172 Avoiding hole 173 Fixed bracket 251 Fixed part 2511 Drive 254 stator 2541 Rotor 2542 First shaft 255 Second shaft 256 Ball 257 Mounting plate 280 First axis Y Second axis P Third axis R
  • a component when a component is considered to be “connected” to another component, it can be directly connected to another component or a component that may have a central setting at the same time.
  • a component When a component is considered to be “set up” to another component, it can be a component that is set directly on another component or that may have a centered setting at the same time.
  • FIG. 1 to FIG. 2 is a motion camera 100 according to a first embodiment of the present invention.
  • the motion camera 100 can be mounted on a movable device for shooting or can be captured by a photographer.
  • the motion camera 100 includes a housing 110, a bracket 120 housed in the housing 110, a power source 130, a pan/tilt mechanism 150, a camera 160, and a circuit board unit 170.
  • the pan/tilt mechanism 150 is mounted on the inner side of the outer casing 110
  • the camera 160 is mounted on the pan-tilt mechanism 150.
  • the bracket 120 has a substantially rectangular frame shape and is disposed outside the pan-tilt mechanism 150 and the camera 160 to protect the pan-tilt mechanism 150 and the camera 160.
  • the bracket 120 can also serve as a carrier for mounting the circuit board unit 170.
  • a power source 130 is located on one side of the cradle 120 for providing power to the motion camera 100, such as providing the PTZ mechanism 150 with the required power to drive the camera 160, providing power to the camera 160, and other power units for the motion camera 100. Provide electrical energy.
  • the circuit board unit 170 is mounted on a side of the bracket 120.
  • the circuit board unit 170 includes a first circuit board unit 171 and a second circuit board unit 172, and the first circuit board unit 171 and the second circuit board unit 172 are disposed in different brackets 120. Sides and electrically connected to each other.
  • the first circuit board unit 171 and the power source 130 are disposed on the same side of the bracket 120 and between the power source 130 and the bracket 120; the second circuit board The unit 172 is mounted on the bottom of the bracket 120.
  • the first circuit board unit 171 and the second circuit board unit 172 are electrically connected to the power source 130, the pan/tilt mechanism 150, and the camera 160, respectively, for controlling the pan-tilt mechanism 150 to move the camera 160 to a predetermined position, and controlling the camera 160. Take a picture.
  • the motion camera 100 further includes a microprocessor, a memory, a controller, an electronic governor, and a resistor disposed on the first circuit board unit 171 and/or the second circuit board unit 172.
  • An element such as a capacitor capable of completing a read command, executing an instruction, and exchanging information with the memory and an external logic component, and the memory and the first circuit board unit 171 and/ Or the second circuit board unit 172 constitutes a microcomputer.
  • the memory is used to store programs and various data, and can access programs or data at high speed and automatically during the operation of the microcomputer.
  • the controller can change the wiring of the first circuit board unit 171 and/or the second circuit board unit 172 in a predetermined order and change the resistance value in the circuit to control the startup, speed regulation, and braking of the pan/tilt mechanism 150. And the reverse action, the controller is able to coordinate and direct the operation of the entire microcomputer system.
  • the electronic governor can control the pan/tilt mechanism 150 to operate according to a set direction, speed, angle, and response time by active operation of the first circuit board unit 171 and/or the second circuit board unit 172. .
  • the resistor is used to adjust and stabilize current and voltage of the first circuit board unit 171 and/or the second circuit board unit 172; the capacitance is used for the first circuit board unit 171 and/or the second circuit
  • the electrical signals in the board unit 172 are filtered, coupled, modulated, and the like.
  • the motion camera 100 further includes other electronic components mounted on the first circuit board unit 171 and/or the second circuit board unit 172. One by one.
  • pan/tilt mechanism 150 can also be disposed on other structures within the outer casing 110, such as the bracket 120, but is not limited thereto.
  • the housing 110 includes a housing 111 and a window 112 disposed on the housing 111.
  • the housing 111 and the window 112 are enclosed as a substantially rectangular receiving cavity 113 for receiving the bracket 120, the power source 130, the pan/tilt mechanism 150, and the camera. 160 and circuit board unit 170.
  • the window 112 is substantially circular and made of a transparent material to facilitate the camera 160 to ingest the outside environment through the window 112. In other embodiments, the window 112 can also be omitted.
  • the housing 111 forms a consistent perforation (not shown) corresponding to the position of the camera 160, so that the camera 160 can directly ingest the external environment through the through hole.
  • the bracket 120 is in close contact with the inner side surface of the housing 111 to further enhance the structural strength of the housing 111, and protect the pan/tilt mechanism 150 and the camera 160 therein.
  • the bracket 120 can be omitted, and the circuit board unit 170 can be directly mounted on the inner side surface of the housing 111.
  • the pan/tilt mechanism 150 includes a first rotary driving member 151, a first turret 152, a second rotary driving member 153, a second turret 154, and a third rotary driving member 155.
  • the first rotary driving member 151 is fixedly disposed on an inner side surface of the housing 111.
  • the circuit board unit 170 corresponding to the first rotary driving member 151 is provided with a avoidance hole 173.
  • the first rotary driving member 151 is inserted through the avoidance hole 173 and fixedly connected to the inner side surface of the housing 111.
  • the first turret 152 is substantially L-shaped, and one end thereof is coupled to the first rotary driving member 151 and is rotated about the first axis Y by the driving of the first rotary driving member 151.
  • the second rotating driving member 153 is disposed at the other end of the first rotating frame 152 away from the first rotating driving member 151.
  • the second turret 154 is also substantially L-shaped, and one end thereof is coupled to the second rotary driving member 153 and is rotated about the second axis P by the driving of the second rotary driving member 153.
  • the third rotary driving member 155 is disposed at the other end of the second rotating frame 154 away from the second rotary driving member 153.
  • the camera 160 is coupled to the third rotary driving member 155 and is rotated about the third axis R by the driving of the third rotary driving member 155.
  • the first rotary driving member 151, the second rotary driving member 153, and the third rotary driving member 155 are electrically connected to the circuit board unit 170, respectively.
  • the first axis Y, the second axis P, and the third axis R are orthogonal to each other.
  • the first axis Y is a heading (Yaw) axis of the pan-tilt mechanism 150
  • the second axis P is a pitch axis of the pan-tilt mechanism 150
  • the third axis R is The Roll axis of the pan/tilt mechanism 150.
  • the first axis Y, the second axis P, and the third axis R may be other angles, which are not limited in the present invention.
  • the housing 111 is made of a metal material, and the power source 130 is attached to the inner side of the housing 111, and heat generated by the power source 130 can be directly led out through the housing 111.
  • the motion camera 100 is disposed in the outer casing 110 of the motion camera 100 by a built-in method to prevent the pan-tilt mechanism 150 and the camera 160 from being shaken by external factors, thereby achieving The stabilizing effect of a sports camera.
  • the pan/tilt mechanism 150 and the camera 160 are respectively disposed in the outer casing 110 of the motion camera 100 to further reduce the overall volume of the motion camera 100, thereby improving the portability of the motion camera 100.
  • the pan/tilt mechanism 100 in the above-mentioned first embodiment adopts a three-axis pan/tilt head; in other embodiments, the pan-tilt mechanism may also be a two-axis or single-axis pan/tilt head, and each axis is driven by a respective rotation. The pieces are driven separately.
  • the pan/tilt mechanism 100 includes at least one rotary drive member mounted on the outer casing 110.
  • the pan/tilt mechanism 100 may be partially located outside of the housing 110.
  • a portion of the rotary drive member of the pan/tilt mechanism 100 is mounted outside the housing 110 and passes through the housing 110 to drive a corresponding turret for rotation.
  • a second embodiment of the present invention provides a motion camera 200 having a structure similar to that of the motion camera 100 in the first embodiment.
  • the motion camera 200 includes a housing (not shown).
  • the bracket 220, the power source 230, the pan/tilt mechanism 250, the camera 260, and the circuit board unit 270 are disposed in the outer casing, and the outer casing is provided with a window, so that the camera 260 transmits the external environment through the window.
  • the difference is that the pan/tilt mechanism 250 is substantially spherical, and the pan-tilt mechanism 250 includes a fixed bracket 251, a first turret 252, a second turret 253, a driving member 254, and two first rotating shafts 255.
  • the fixing bracket 251 has a substantially semi-annular shape, and a fixing portion 2511 is provided at a substantially central position on the outer side thereof, and the fixing portion 2511 can be fixed by a fastener such as a bolt (not shown).
  • the two first rotating shafts 255 are respectively rotatably mounted on both ends of the fixing bracket 251 and disposed coaxially.
  • the first turret 252 is substantially annular and is rotatably mounted between the two first rotating shafts 255 about the first axis Y.
  • the two second rotating shafts 256 are respectively rotatably mounted on opposite sides of the first rotating frame 252 and disposed coaxially.
  • the two second rotating shafts 256 cooperate with the two first rotating shafts 255 and are respectively located at four equal positions of the first turret 252.
  • the second turret 253 has a substantially annular shape and is rotatably mounted between the two second rotating shafts 256 about the second axis P.
  • the camera 260 is located substantially at the center of the center of the pan-tilt mechanism 250, and is rotatably received in the second turret 253 about the third axis R.
  • a plurality of balls 257 are disposed between the camera 260 and the second turret 253 to reduce the rotational friction between the camera 260 and the second turret 253.
  • the motion camera 200 further includes a mounting plate 280, and the pan/tilt mechanism 250 is mounted on the mounting plate 280.
  • the fixing portion 2511 of the fixing bracket 251 is fixedly connected to the mounting plate.
  • the mounting plate 280 is fixed to an inner side of the outer casing.
  • the mounting plate 280 and the window are respectively disposed on opposite sides of the outer casing, but are not limited thereto. It can be understood that the mounting plate 280 can also be omitted, and the fixing bracket 251 is fixedly connected to the outer casing.
  • the mounting board 280 can also be a circuit board, which can be used as a supplement to the circuit board unit 270 to implement some functions of the pan/tilt mechanism 250 and/or the lens 260. , no longer detailed here.
  • the driving member 254 is a spherical motor including a stator 2541 and a rotor 2542.
  • the stator 2541 is substantially hemispherical, and is fixedly disposed on the fixing bracket 251 and electrically connected to the circuit board unit 270.
  • the rotor 2542 is fixedly coupled to one end of the camera 260 toward the stator 2541 and is magnetically coupled to the stator 2541.
  • the stator 2541 is provided with a plurality of electromagnetic induction coils (not shown), and the plurality of electromagnetic induction coils are jointly formed with a first magnetic field;
  • the rotor 2542 is provided with a plurality of permanent magnets (not shown), and a plurality of permanent magnets.
  • a second magnetic field is formed together, and the second magnetic field is magnetically coupled to the first magnetic field.
  • the first axis Y, the second axis P, and the third axis R are orthogonal to each other.
  • the first axis Y is a heading (Yaw) axis of the pan-tilt mechanism 150
  • the second axis P is a pitch axis of the pan-tilt mechanism 150
  • the third axis R is The Roll axis of the pan/tilt mechanism 150.
  • the first axis Y, the second axis P, and the third axis R may be other angles, which are not limited in the present invention.
  • the motion camera 200 can drive the camera 260 to rotate in three axial directions respectively through a driving member 254, thereby effectively reducing the power consumption generated by the plurality of driving members 254, and further reducing the space volume of the pan/tilt mechanism 250. .
  • the pan/tilt mechanism 100 in the second embodiment is a three-axis pan/tilt head; in other embodiments, the pan/tilt head mechanism may also be a two-axis pan/tilt head, and the cameras are respectively in a spherical motor.
  • the driving is rotated about the first axis Y and the second axis P.
  • the pan/tilt mechanism is a three-axis pan/tilt
  • the pan-tilt mechanism includes a spherical motor and a rotating electrical machine
  • the spherical motor drives the camera around the first axis Y and the second The axis P rotates; the rotating motor drives the camera to rotate about a third axis R.
  • the pan/tilt mechanism is a three-axis pan/tilt
  • the pan-tilt mechanism includes a spherical motor and three rotating electrical machines
  • the spherical motor can drive the camera around the first axis Y
  • the second axis P and the third axis R rotate; the three rotating electrical machines respectively drive the camera to rotate about the first axis Y, the second axis P and the third axis R.
  • the above-mentioned pan/tilt mechanism has two driving modes of a spherical motor and a rotating electric machine, and each driving mode can drive the camera to rotate about the first axis Y, the second axis P and the third axis R, thereby further enhancing the cloud.

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  • Engineering & Computer Science (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Accessories Of Cameras (AREA)
  • Studio Devices (AREA)

Abstract

L'invention concerne une caméra d'action (100, 200), comprenant une coque (110) et une caméra (160, 260). La caméra d'action (100, 200) comprend en outre un mécanisme de support (150, 250) au moins partiellement disposé à l'intérieur de la coque (110). La caméra (160, 260) est disposée sur le mécanisme de support (150, 250) et peut photographier et/ou ajuster un angle de photographie de façon stable au moyen du mécanisme de support (150, 250). La caméra d'action (100, 200) réduit en outre la quantité d'espace qu'elle occupe, tout en augmentant la stabilité.
PCT/CN2017/086171 2017-05-26 2017-05-26 Caméra d'action Ceased WO2018214162A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/CN2017/086171 WO2018214162A1 (fr) 2017-05-26 2017-05-26 Caméra d'action
CN201780065700.0A CN109863086A (zh) 2017-05-26 2017-05-26 运动相机

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2017/086171 WO2018214162A1 (fr) 2017-05-26 2017-05-26 Caméra d'action

Publications (1)

Publication Number Publication Date
WO2018214162A1 true WO2018214162A1 (fr) 2018-11-29

Family

ID=64396057

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2017/086171 Ceased WO2018214162A1 (fr) 2017-05-26 2017-05-26 Caméra d'action

Country Status (2)

Country Link
CN (1) CN109863086A (fr)
WO (1) WO2018214162A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210203826A1 (en) * 2016-09-16 2021-07-01 Gopro, Inc. Vibration Damping Gimbal Sleeve for an Aerial Vehicle
WO2022011945A1 (fr) * 2020-07-16 2022-01-20 深圳市大疆创新科技有限公司 Ensemble de stockage et ensemble dispositif de caméra à cardan portative
US11584545B2 (en) * 2019-12-20 2023-02-21 L3Harris Technologies Integrated Systems L.P. Portable electro-optical/infrared turret systems and methods for using the same

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004001941A1 (fr) * 2002-06-25 2003-12-31 Korea Electronics Technology Institute Dispositif a moteur spherique
US20100019120A1 (en) * 2004-12-13 2010-01-28 Optical Alchemy, Inc. Multiple axis gimbal employing nested spherical shells
CN201403041Y (zh) * 2009-04-21 2010-02-10 安徽大学 三自由度运动永磁球形步进电动机
CN204979266U (zh) * 2015-07-16 2016-01-20 零度智控（北京）智能科技有限公司 具有保护壳的云台结构及云台摄像装置
US20160344906A1 (en) * 2015-05-21 2016-11-24 Jason Hernandez Device and Method for Gaze Attraction Toward Camera
CN106428595A (zh) * 2016-10-20 2017-02-22 南京壹诺为航空科技有限公司 一种小型无人机内置式稳像云台

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3687453B2 (ja) * 1999-12-27 2005-08-24 松下電器産業株式会社 電動雲台
TWI421614B (zh) * 2011-04-01 2014-01-01 Chieng Ming Ind Co Ltd Underwater camera
KR101369735B1 (ko) * 2012-06-26 2014-03-06 (주)대호아이앤에스티 팬/틸트 볼 카메라
US20150077614A1 (en) * 2013-08-16 2015-03-19 Simon P King Rotate-pan-tilt camera for videoimaging, videoconferencing, production and recording
WO2015196487A1 (fr) * 2014-06-27 2015-12-30 深圳市大疆创新科技有限公司 Moteur et dispositif panoramique horizontal-vertical
CN105207408B (zh) * 2015-10-26 2018-01-30 深圳市道通智能航空技术有限公司 一种电机、云台及飞行器
CN205560201U (zh) * 2016-01-26 2016-09-07 深圳市大疆创新科技有限公司 云台及使用该云台的拍摄设备和无人飞行器
CN206012980U (zh) * 2016-07-29 2017-03-15 深圳市大疆创新科技有限公司 云台、拍摄设备和无人飞行器

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004001941A1 (fr) * 2002-06-25 2003-12-31 Korea Electronics Technology Institute Dispositif a moteur spherique
US20100019120A1 (en) * 2004-12-13 2010-01-28 Optical Alchemy, Inc. Multiple axis gimbal employing nested spherical shells
CN201403041Y (zh) * 2009-04-21 2010-02-10 安徽大学 三自由度运动永磁球形步进电动机
US20160344906A1 (en) * 2015-05-21 2016-11-24 Jason Hernandez Device and Method for Gaze Attraction Toward Camera
CN204979266U (zh) * 2015-07-16 2016-01-20 零度智控（北京）智能科技有限公司 具有保护壳的云台结构及云台摄像装置
CN106428595A (zh) * 2016-10-20 2017-02-22 南京壹诺为航空科技有限公司 一种小型无人机内置式稳像云台

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210203826A1 (en) * 2016-09-16 2021-07-01 Gopro, Inc. Vibration Damping Gimbal Sleeve for an Aerial Vehicle
US11930273B2 (en) * 2016-09-16 2024-03-12 Gopro, Inc. Vibration damping gimbal sleeve for an aerial vehicle
US11584545B2 (en) * 2019-12-20 2023-02-21 L3Harris Technologies Integrated Systems L.P. Portable electro-optical/infrared turret systems and methods for using the same
WO2022011945A1 (fr) * 2020-07-16 2022-01-20 深圳市大疆创新科技有限公司 Ensemble de stockage et ensemble dispositif de caméra à cardan portative

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