CA2536826C - Stabilized three-axis camera head - Google Patents

Abstract

A remote camera head and stabilized camera system contain a roll frame, tilt frame and pan frame in multiple positions. The camera head can be expanded or reduced in size as needed based on the space requirements of the camera and camera accessories mounted on the camera head. Control circuits are provided to compensate for drift, to allow manual aiming of the camera during stabilized camera operation, and for providing rapid leveling. Waterproof or sealed slip ring assemblies and connectors allow the camera head to operate in wet environments, or even when submerged in water.

Description

STABILIZED THREE-AXIS CAMERA HEAD
BACKGROUND OF THE INVENTION

[0001] The field of the invention is remote camera heads and stabilized platforms and systems for cameras. In motion picture, television, or video filming or recording, the camera is often supported on a vehicle, to follow an action or moving sequence, to achieve a desired camera angle or effect, or to film occupants in or on a vehicle. Various specialized camera cranes, dollys, and other mobile platforms have been used for this purpose.

[0002] Over the last several years, remote camera heads have increasingly been used. A remote camera head is an apparatus that allows the camera to be moved, aimed, or controlled from a remote location (i.e., a location not immediately behind the camera). Typically, a remote camera head is mounted on a crane arm. The crane arm can move the camera head, and the camera on the head, into locations not accessible using conventional camera operations (i.e., with a camera operator behind the camera and controlling camera movement by hand). For example, a camera on a camera head may be suspended on a crane arm extending out over the side of a tall building, a cliff, a waterfall, etc., i.e., in a position where it would be unsafe, impractical, or impossible to perform conventional camera operations.

[0003] In general, remote camera head operations involve placing the camera on a remote camera head which can perform pivoting or rotational movement in three axes, known as pan, tilt, and roll or dutch. Electric motors on or in the remote camera head are remotely controlled (via cables or wireless links) by a camera head operator, typically on the ground, or on the vehicle supporting the crane arm. Operation of the camera itself is similarly remotely controlled.

[0004] While camera heads have been successfully used in the past, several disadvantages remain. As camera heads generally have various electrical and electronic components (motors, sensors, etc.), they are typically limited to use only in clean and dry conditions. Adverse environmental conditions, such as rain, snow, dust, sand, etc., can often cause degraded performance or failures with camera heads. Accordingly, there is a need for a rugged camera head providing reliable performance in all weather conditions.

[0005] Many camera heads are relatively difficult and time consuming to set up, balance, operate, or reconfigure. Since production time can be extremely expensive, even short delays associated with use of a camera head can be disadvantageous. Consequently, there is a need for a camera head which can be quickly and easily transported, installed, and made ready for use.

[0006] Many camera heads are set up for remote control using motors which drive or move components of the camera head. However, to preview lens angles, or for other reasons, a camera operator may want to manually position the camera. This typically requires that the motors be disconnected or disengaged, to allow the camera head to be easily moved by hand.
Unfortunately, with many camera heads, this disengagement for hand movement, can be time consuming and difficult. Similarly, re-engaging or reconnecting the motors for electrical movement of the camera head, can also be time consuming.

[0007] In filming or recording with motion picture or television or video cameras, it is important for the camera to be maintained in a stable position.
In the most basic form, camera stability has been achieved by mounting the camera on a tri-pod. However, when the camera itself is mounted on and moves with a vehicle, maintaining camera stability often becomes difficult.
For example, with a camera mounted on a camera car moving along a roadway and filming a fixed subject on the ground or another moving vehicle, the camera and the lens of the camera will necessarily move in unintended and undesirable ways, due to various factors. These factors may include changes in the roadway direction or inclination, changes in the vehicle orientation, due to shifting gravitational or inertial loads, as well as for other reasons.

Undesirable movement can be especially problematic when the camera is mounted on an aircraft, where movement readily occurs along three dimensions, and where wind buffeting of the camera can be extreme. The undesirable camera lens movement resulting from these factors reduces the quality of the filmed or recorded images, by causing the images to be improperly framed, or to appear jumpy or erratic.

[0008] To maintain the camera lens in a stable position in these types of situations, various camera stabilization systems have been proposed.
Generally, these camera stabilization systems rely on gyrostabilization and feedback techniques which detect unintended or undesirable movement of the camera, and then compensate for that movement via motors driving the camera platform. The term gyrostabilization here means any camera movement compensation system using position, rate, or acceleration sensors, whether "gyroscopic" or of another type.

[0009] While these types of stabilization systems have been successfully used in the past, various disadvantages remain. The gimbal system used in existing stabilized camera systems, which allows the camera to pivot about three perpendicular directions, are often large and relatively time consuming or difficult to balance. This can restrict camera movement and positioning and also make transport, installation and set-up (including balancing) more difficult.

Moreover, existing systems generally have large moments of inertia, making them relatively slower in responding to correction forces applied by the motors.
Accordingly, there is a need for a camera stabilization system which is compact, lightweight, and agile in responding to correction signals and forces.

[0010] The camera operator, cinematographer, or director will often want to manually aim the camera, by simply grabbing the camera with the hands, and aiming it as desired. Existing camera stabilization systems, when turned on, will automatically resist such manual movement. While this resistance can be overcome by applying force sufficient to overcome the torque limits of the motors in the stabilization system, this results in jerky and imprecise camera movement. As a result, manually aiming or positioning of the camera by forcibly overriding stabilization system has disadvantages, and generally is almost never acceptable during filming.

[0011] On the other hand, turning the stabilization system off to perform hand or manual camera aiming or movement results in loss of all stabilization functions. With the stabilization turned off, the only forces holding the camera in position are the frictional forces in the various rotation joints. Based on the weight of the camera and other factors, these frictional forces may be insufficient to even hold the camera at any desired position. In' addition, due to static and dynamic friction characteristics, achieving smooth and accurate camera movement, even with the stabilization system turned off, can be difficult or impossible. Accordingly, there is a need for a camera stabilization system which allows for smooth and accurate manual aiming.

[0012] Over longer periods of time, drift in existing camera stabilization systems can cause the camera to become improperly positioned. The severity of drift varies with the accuracy of the sensors in the system. Due to drift, under certain conditions, the camera may require repositioning before filming or recording is continued after a lunch break or other pause. This can result in delays and added production costs. Accordingly, there is a need for a camera stabilization system which compensates for or eliminates drift.

[0013] Existing camera stabilization systems have various other disadvantages as well, relating to backlash in the drive systems, balancing, large moments of inertia, controls and accuracy of positioning.

[0014] Accordingly, various engineering challenges remain in designing an improved camera head and an improved camera stabilization system.
STATEMENT OF THE INVENTION

[0015] After extensive research and ' development, the various engineering challenges described above associated with camera heads and stabilized camera systems have now been overcome in new systems providing significantly improved performance and advantages. These advantages include all weather operation, submerged operation, rapid set-up and adjustment, wide ranging adaptability for handling cameras of various shapes, sizes, and weight, compact design, precise positioning, and improved performance features and characteristics.

[0016] In a first aspect, a camera support or camera head has a pan frame, a tilt frame securable onto the pan frame at multiple positions on the pan frame, and a tilt frame securable onto the pan frame at multiple positions on the pan frame. A quick release lever is advantageously used to secure the frames at desired positions, to configure the camera head as desired.

[0017] In a second aspect the pan frame includes a pan housing, a pan arm rotatably attached to the pan housing and a pan motor for moving the pan arm relative to the pan housing. The tilt frame includes a tilt housing, a tilt arm rotatably attached to the tilt housing and a tilt motor for moving the tilt arm relative to the tilt housing. The tilt frame is securable onto the pan arm at multiple positions along the pan arm. In an additional aspect of the invention, a roll frame is also included, having a roll housing and a camera platform rotatably attached to the roll housing, and a roll motor for moving the camera platform relative to the roll housing. In this design, the roll frame is also securable onto the tilt arm at multiple positions along the tilt arm. Since the frames or arms can be quickly moved into a desired position, and then securely locked into place, via a cam lever or other locking device, the camera head can be quickly and easily configured to carry a wide range of cameras and/or related equipment.

[0018] In a third aspect of the invention, a camera head includes a slip ring assembly for each axis of rotation, and with waterproof cable segments extending between the slip ring assemblies. Electrical connections are made water proof or resistant. Bearings within the camera head are sealed. This allows the camera head to be used in the rain, or even underwater, without loss of performance.

[0019] In a fourth aspect of the invention, a pan or first shaft is rotatably supported within a pan or first housing. A tilt or second frame is attached to the first shaft, and the first shaft is sealed against the first housing. A
first gear is linked to the first shaft through a first clutch. The first gear is linked to the first motor. At least one clutch operation lever on the housing is moveable from a first position, wherein the lever engages the first clutch to allow the first motor to drive the first shaft, to a second position, wherein the lever disengages the first clutch, allowing the first shaft to rotate free of the motor.
This allows for quickly switching the camera head over between automatic operation (via the motors), to manual operation (i.e., positioning the camera by hand). In addition, since the motors are de-coupled during manual operation, only low force is needed to move the frames. This makes precise camera positioning easier and faster.

[0020] In a fifth aspect of the invention, a stabilized camera system includes a roll or dutch frame pivotably attached to a pan frame. The roll or dutch frame includes a parallelogram linkage. A tilt frame is pivotably attached to the parallelogram linkage of the roll frame. This results in a more compact and lightweight design. With this design, the camera system can also be more quickly and easily installed and balanced.

[0021] In a sixth aspect of the invention, a manual camera aiming mode provides electronically controllable fluid dampening head characteristics. Via electronic controls, the amount of dampening and inertia encountered during manual movement or aiming of the camera can be adjusted. This allows for smooth positioning or aiming of the camera by hand. It also allows the camera to be supported with fluid head-like characteristics.

[0022] In a seventh aspect of the invention, a camera stabilization system uses feedback from a position sensor on the camera platform to reduce or eliminate drift. As a result, even using sensors of moderate accuracy, drift can be virtually eliminated or reduced to acceptable levels.

[0023] In an eighth aspect of the invention, a dutch or roll axis control circuit provides a fast to horizon control mode, for rapidly moving the camera platform to horizontal. This feature allows the camera operator to rapidly confirm that the camera is level relative to the horizon or the "local horizon".

[0024] In a ninth aspect of the invention, first and second electric motors drive movement of pan, roll, and tilt frames or structures. This feature reduces backlash providing greater accuracy in control and positioning.

In another aspect of the invention, there is a camera head comprising: a first frame; a first arm rotatably attached to the first frame;
a first motor for rotating the first arm relative to the first frame, with the first motor enclosed within a sealed first housing; a second frame attached to the first arm; a second arm rotatably attached to the second frame; a second motor for rotating the second arm relative to the second frame, with the second motor enclosed within a sealed second housing; a first shaft rotatably supported within the first housing, with the second frame attached to the first shaft, and the first shaft sealed against the first housing, a first gear linked to the first shaft through a first clutch, and with the first gear linked to the first motor, and one or more clutch drive pins sealed against the first housing, and moveable from a first position, wherein the first motor drives the first shaft through the first clutch, to a second position, wherein the first shaft can rotate free of the motor.

In a further aspect of the invention, there is a remote camera head comprising: a first frame; a first sealed housing on the first frame; a first arm rotatably attached to the first frame; a first motor for rotating the first arm relative to the first frame, with the first motor enclosed within the first sealed housing; a second frame attached to the first arm; a second sealed housing on the second frame; a second arm rotatably attached to the second frame; a second motor for rotating the second arm relative to the second frame, with the second motor enclosed within the second sealed housing; a first hollow shaft rotatably supported within the first sealed housing, with the second frame attached to the first shaft, and the first shaft sealed against the first sealed housing; a first gear linked to the first shaft through a first clutch, and with the first gear linked to the first motor; a first slip ring assembly extending into the first hollow shaft; a first shaft plug within and sealed against the first hollow shaft; a first electrical cable extending into a first end of the first slip ring assembly via a waterproof connection; and a second electrical cable extending through a waterproof connection in the first shaft plug and into a second end of the first slip ring assembly.

In a still further aspect of the invention, there is a camera support comprising: a first housing having a first interior sealed space; a first purge gas port on the first housing connecting into the first interior sealed space, for delivering a purge gas into the first interior sealed space; a first motor supported by the first housing; a second housing having a second interior sealed space, and with the second housing linked to the first motor for rotational movement of the second housing relative to the first housing about a first axis; a second motor supported by the second housing; a second purge gas port on the second housing connecting into the second interior sealed space, for delivering a purge gas into the second interior sealed space; a third housing linked to the second motor for rotational movement of the third housing relative to the second housing about a second axis substantially perpendicular to the first axis; and a lock pin moveable between a lock position, where the lock pin extends between the first housing and the second housing, to prevent movement between them, and an unlock position, wherein the lock pin is withdrawn from one of the first and second housings, to allow rotational movement between them.

In yet another aspect of the invention, there is a camera support comprising: a first housing having a first interior sealed space; a first purge gas port on the first housing connecting into the first interior sealed space, for delivering a purge gas into the first interior sealed space; a first motor supported by the first housing; a second housing having a second interior sealed space, and with the second housing linked to the first motor for rotational movement of the second housing relative to the first housing about a first axis; a second motor supported by the second housing; a second purge gas port on the second housing connecting into the second interior sealed space, for delivering a purge gas into the second interior sealed space; a third housing linked to the second motor for rotational movement of the third housing relative to the second housing about a second axis substantially perpendicular to the first axis; a first shaft rotatably -10a-supported within the first housing, with the second housing attached to the first shaft, and the first shaft sealed against the first housing, a first gear linked to the first shaft through a first clutch, and with the first gear linked to the first motor, and one or more clutch drive pins sealed against the first housing, and moveable from a first position, wherein with first motor drives the first shaft through the first clutch, to a second position, wherein the first shaft can rotate free of the motor.

[0025] The invention resides as well in subcombinations and subsystems of the components, elements, and steps described. Each of the aspects described above may be used alone, or in combination with one or more of the other aspects. The essential elements are described in the claims, with no one of the aspects above essential to all embodiments of the invention.

BREIF DESCRIPTION OF THE DRAWINGS

[0026] In the drawings, wherein the same element number generally indicates the same element in each of the views:

[0027] Fig. 1 is a perspective view of the present camera head in use, mounted on a telescoping crane arm.

[0028] Fig. 2 is a perspective view of the camera head shown in Fig. 1, in an upright position.

- 1 0b -[0029] Fig. 3 is a perspective view of the camera head shown in Fig. 2, with the camera platform inverted.

[0030] Fig. 4 is a side view, in part section, of the camera head shown in Figs. 2 and 3, with the camera and electrical components omitted for clarity of illustration.

[0031] Fig. 5 is an enlarged detail view, in part section, of the pan frame shown in Fig. 4.

[0032] Fig. 6 is an enlarged detail view, in part section, of the tilt frame shown in Fig. 4.

[0033] Fig. 7 is an enlarged detail view, in part section, of the roll frame shown in Fig. 4.

[0034] Fig. 8 is a section view taken along line 8-8 of Fig. 4.

[0035] Fig. 9 is a bottom view taken along line 9-9 of Fig. 4.

[0036] Fig. 10 is a side elevation view, in part section, of the camera head shown in Fig. 4.

[0037] Fig. 11 is an enlarged detail view, in part section, of the pan housing shown in Fig. 10.

[0038] Fig. 12 is an enlarged detail view, in part section, of the roll housing shown in Fig. 10.

[0039] Fig. 13 is an enlarged detail view, in part section, of the tilt housing shown in Fig. 10:

[0040] Fig. 14 is a front elevation view of the camera platform, taken along line 14-14 of Fig. 10.

[0041] Fig. 15 is a plan view of the camera head shown in Figs. 4 and 10.

[0042] Fig. 16 is a side elevation view of the tilt frame, taken along line 16-16 of Fig. 15.

[0043] Fig. 17 is an enlarged detail view, in part section, of components of the tilt frame and roll frame shown in Fig. 15.

[0044] Fig. 18 is a side view showing the tilt frame in a first or retracted position on the pan frame.

[0045] Fig. 19 is a side view thereof, showing the tilt frame in a second or extended position on the pan frame.

[0046] Fig. 20 is an enlarged section view of the roll housing shown in Figs. 7, 10, and 12.

[0047] Fig. 21 is a further enlarged section view thereof.

[0048] Fig. 22 is an enlarged view of the pan axis stop pin shown in Fig. 2.

[0049] Fig. 23 is an enlarged view, in part section, of the connector pairs, shown in Figs. 1 and 10.

[0050] Fig. 24 is a side view of a remote camera head and camera stabilization system mounted on a camera crane having a fixed length boom arm.

[0051] Fig. 25 is a front and left side perspective view of the camera system shown in Fig. 24.

[0052] Fig. 26 is a front and right side perspective view thereof.

[0053] Fig. 27 is a plan view of the camera system shown in Figs. 25 and 26.

[0054] Fig. 28 is a left side elevation view thereof.

[0055] Fig. 29 is a front view thereof.

[0056] Fig. 30 is a schematically illustrated side view of the present camera support system showing alternative positions.

[0057] Fig. 31 is a front view thereof with the camera removed, for purpose of illustration.

[0058] Fig. 32 is a schematic illustration of an automatic leveling system.

[0059] Fig. 33 is a schematic illustration of a drift compensation system.

[0060] Fig. 34 is a schematic illustration of a control signal distribution system.

[0061] Fig. 35 is a schematic illustration of a camera stabilization system including a manual camera aiming mode function.

[0062] Fig. 36 is a schematic illustration of the manual camera aiming mode circuit used in Fig. 35.

[0063] Fig. 37 is a plan view of a control panel for use with the system shown in Fig. 35.

[0064] Fig. 38 is a perspective view of a motor assembly as used on the system shown in Figs. 25-31.

DETAILED DESCRIPTION OF THE DRAWINGS

[0065] Turning now in detail to the drawings, as shown in Fig. 1, the camera head 50 of the invention is supported on the nose or front end 42 of a crane arm 40. The crane arm 40 is supported on an arm or post 32 of a mobile dolly 30. The dolly 30 is typically on wheels 34, so that it can easily be maneuvered and steered. Counterweights 44 are typically provided at the back end of the crane arm 40, for balancing.

[0066] In Fig. 1, a motion picture or video camera 60 is attached onto the head 50. The front end or nose 42 of the crane arm 40, the head 50, and the camera 60 are submerged in a pool or tank of water 54, to film an action sequence of a diver 52. Of course, Fig. 1 shows but a single example of use of the camera head 50. In practice, the camera head 50 can be mounted on various motorized camera cranes, carts, dollys or other mobile bases, to position and maneuver a camera 60 at elevated positions, near ground level positions, below ground level positions, within interior spaces of buildings or enclosures, etc. Indeed, the camera head 50 maybe used in any application where remote positioning and maneuvering of a camera 60 is desired.

CAMERA HEAD DESIGN

[0067] In Figs. 2 and 3, the camera head 50 is shown supported on a track 41 of an alternative camera crane or dolly. The camera head 50 comprises three principle assemblies or units, specifically a pan frame or assembly generally indicated at 70, a tilt frame or assembly generally indicated at 72, and a roll or dutch frame or assembly generally indicated at 74. The pan frame 70 is supported on a crane arm 40, track 41 or similar support and provides pivoting or rotational movement about a pan-axis P, typically a vertical upright axis. This allows the camera 60 to be moved with a panning or clockwise/counterclockwise sweeping horizontal movement. The tilt frame 72 supported on the pan frame 70 provides for pivoting or rotational movement about a tilt axis T, to change the elevation angle of the camera 60. The roll frame 74 which is supported on the tilt frame 72 provides for pivoting or rotational movement about a roll axis R. In contrast to Fig. 2, Fig. 3 shows the camera platform inverted, at a near 180 roll or "dutch angle. Since the camera head 50 allows the camera 60 to be pivoted or rotated about each of the three axes, the lens of the camera 60 can be moved into any desired angular position.

[0068] Referring to Figs. 4, 5, and 11, the pan frame 70 includes a pan housing 80 containing or supporting a pan motor 86. As shown in Fig. 11, a pan shaft 82 is joined to a top plate ring 83 which rotates relative to housing 80.. A pan gear 84 is attached to the shaft 82 through a clutch assembly 102 providing overload protection and allowing disengagement for quick and easy manual operation. The electric pan motor 86 drives a worm gear 110 which meshes with the pan gear 84. A pan axis slip ring assembly 88 is supported on or in the pan housing 80, to provide electrical connections through the rotating joint. A locking nut 85 around the top end of the pan housing 80 is used to attach the camera head 50 to a crane arm or other support.

[0069] Referring to Figs. 3-5 and 22, a pan arm 96 is rotatably attached to the pan housing 80 via a sealed bearing 92. The pan arm 96 rotatably seals against the pan housing 80 via an O-ring seal 94. Referring to Fig. 11, when electrical power is applied to the pan motor 86, the worm gear 110 drives the pan gear 84 through the clutch 102 causing the pan shaft 82 to rotate. As the pan arm 96 is rigidly attached to the pan shaft 82, the pan arm 96 therefore rotates, while the pan housing 80 remains fixed in place. To prevent inadvertent relative movement of the pan arm 96, a spring biased pan axis stop pin 90 on the pan housing 80 can be engaged into an opening or hole 91 in the pan arm 96, as shown in Figs. 2 and 22, locking them together against rotation.

[0070] Referring momentarily to Fig. 9, which is a bottom view looking up of the pan housing 80, a pair of cam engagement levers 98 lock the pan arm 96 into engagement with the pan shaft 82. For manual movement of the pan arm 96, independent of, or without use of the motor 86, the cam levers 98 are flipped over or released. This allows the pan arm 96 to rotate freely, for hand or manual positioning or movement.

[0071] Figs. 20 and 21 show operation of the cam levers 98. A cam surface on each cam lever 98 rests against a clutch drive pin 99, which contacts the first or outer clutch plate 185 of the roll clutch 184. With the levers in an engaged position, the cam levers drive the clutch drive pins 99 hard against the clutch plate 185. This engages the clutch, causing the shaft 162 to rotate when the roll motor 166 is turned on. The cam levers and clutch drive pins are dimensioned to limit the maximum applied torque of the clutch to a preset limit. With the cam levers 98 flipped over (about 180 degrees), the clutch drive pins 99 are released, and the clutch is disengaged. The shaft 162, and the entire camera platform supported on the shaft 162, can then be freely rotated by hand, with minimum force. Q-rings 101 on the clutch drive pins 99 seal the pins against the housing 80, while still allowing the pins to move axially.

[0072] As shown in Fig. 9, a drag lever 100 acts on a drag collar 120 around the base or bottom of the pan housing 80. A Teflon (Fluorine resins) ring 122 is positioned between the drag collar 120 and the pan shaft 82.
Adjustment of the drag lever 100 increases or decreases friction on the pan arm 96. The drag lever 100 has a cam surface including flat segments to allow for incremental adjustment of drag. Similar drag adjustment is provided for the tilt and roll frames.

[0073] Referring to Figs. 4 and 6, the tilt frame 72 includes a tube angle 152 attached to a connecting tube 144 by an assembly bolt 142. The assembly bolt 142 engages into a bolt plate 146 within the connecting tube 144, holding the tube angle 152 at an angle (preferably about 35 ) to the axis of the connecting tube 144. Of course, these components may also be perpendicular, or at other angles as well. Alignment pins 145 extend from the connecting tube 144 into the tube angle 152, to help rigidly attach them together, as shown in Fig. 6.

[0074] Referring still to Fig. 6, a tilt axis housing 130 is attached to the connecting tube 144 at the (lower or bottom) end opposite from the tube angle 152. The tilt axis housing 130 includes components analogous to those on or in the pan axis P housing 80 as described above. Specifically, an electric tilt motor 136 on or in the tilt housing 130 has a motor shaft with a worm gear 110 meshed with a tilt axis drive gear 134. The tilt drive gear 134 is linked to a tilt axis shaft 132 through a clutch 102. A tilt arm assembly 153 is rigidly connected to the tilt axis shaft 132. A tilt axis slip ring assembly 138, and a tilt axis stop pin 140 are provided on or in the tilt axis T housing 130. The tilt axis stop pin 140 is similar to the pan axis stop pin 90 shown in Fig. 22, except that it is extendible into holes in a disk 133 joined to the tilt shaft 132.
Referring momentarily to Fig. 10, cam release levers 98, and a drag/lock lever 100 and collar 120 are also provided on the tilt housing 130, similar to the pan housing described above.

[0075] Turning to Fig. 8, the tube angle 152 of the tilt frame 72 is preferably a generally U or C-shaped channel section. The pan arm 96 extends into the tube angle 152. Rollers 222 supported on bearings 224 in the tube angle 152 allow the tube angle 152 and the entire tilt frame 72, to move in or out along the pan arm 96, when the cam lock 220 is released. The rollers 222 roll and/or slide within a dovetail or undercut groove in the pan arm 96.
This allows the head 50 to be moved into the alternative positions shown in Figs. 18 and 19. As a result, the head 50 can be expanded or contracted as desired. For example, when a small size camera 60 is used, the head 50 can be positioned as shown in Fig. 18, providing a compact design, yet with adequate clearance for the camera 60, as well as any lenses, film magazines, batteries, or other accessories provided with the camera 60.

[0076] On the other hand, for handling large cameras, the head 50 can be expanded, as shown in Fig. 19, to provide adequate space for mounting the camera and camera accessories. Referring to Fig. 8, when the tilt frame 72 is positioned as desired on the pan arm 96, the cam lock 220 is closed by pushing the cam lever down. This creates a large clamping force which locks the tilt frame 72 into position. Teflon (fluorine containing resins) tape is advantageously placed on the bottoms and sides of the pan arm 96 and the tilt frame tube extension 158, to allow for easy sliding movement when the cam lock 220 is released. When the cam lock 220 is released or opened, a gap of about 0.2 or 0.3 mm opens between the pan arm 96 and the tube angle 152.

The rollers 222 are then released and are free to roll, as they are no longer clamped down by the compression of the pan arm 96 against the tube angle 154 by the cam lever 220. The load or weight of the tilt frame is then carried by the rollers 222. This allows for fast and accurate low friction sliding movement of the tube angle 152, to obtain the desired size of the camera head. The cam lever 220 is then returned to the down or locked position, tightly clamping and locking the tube angle 152 and the pan arm together, in a single hand motion.

[0077] Referring to Figs. 3 and 15, the tilt arm assembly 153 includes a tilt frame tube 154, preferably oriented perpendicular to the tilt shaft 132.
A tilt frame extension section 158 is joined to the tilt frame tube 154 through an angle section 156, and is preferably generally parallel to the tilt shaft 132, and perpendicular to the tilt frame tube 154.

[0078] Referring now to Figs. 4, 7, 10, 12, 15, and 17, the roll or dutch frame 74 includes components similar to those described above relative to the pan and roll frames. Specifically, a roll housing 160 has a motor 166 which drives a roll axis gear 164 through a worm gear 110 on the motor shaft. The angle on the worm gear 110 is selected so that the worm gears 110 can be back driven. This allows the pan, tilt, and roll frames to be manually positioned, if needed, without releasing the cam locks 98 and offers added resistance to movement when desired. The roll gear 164 drives a roll shaft 162 through a clutch 102. The clutches 102 preferably have a preset torque limit. If the limit is exceeded, the clutch slips. This helps to protect the motor, gears, as well as camera equipment on the head 50. The torque limit is high enough to allow the motors to rapidly move the pan, tilt, and roll frames.

However, the torque limit is also low enough to improve the safety of persons working around the camera head, and to prevent damage to the camera head.

[0079] Referring to Figs. 7, 17, and 20, as with the pan and tilt housings, the roll housing 160 also includes a slip ring assembly 168 and a stop pin 170, which can be engaged or locked -in, to prevent any roll axis rotation.

Engagement cams 98 are provided to engage and disengage the clutch 102, to disconnect the roll motor 166 from the roll shaft 162, e.g., for easy movement of the camera by hand.

[0080] As shown in Fig. 7, a roll housing arm 180 is attached to the roll housing 160 via alignment pins 176 and a connecting bolt 174. The roll housing arm 180 is attached to the tube extension 158 of the tilt arm assembly 153 via rollers and a cam lock 220, as shown in Fig. 8. This allows the roll frame 74 to move in and out relative to the tilt frame 72, in the same way that the tilt frame 72 can be moved relative to the pan frame 70, as shown in Figs.
18 and 19.

[0081] Referring to Figs. 2, 10, 14, and 15, a camera platform 200 is rigidly attached to the roll shaft 162. The camera platform 200 has a slotted base plate 202 attached perpendicularly to a back plate 206. Gusset plates 210 are attached to the base plate 202 and back plate 206. The vertical position of the camera platform 200 relative to the roll axis R can be adjusted by releasing cam levers 212 (shown in Fig. 14), vertically positioning the camera platform 200, via sliding movement on rollers 205, and then locking the cam levers 212. Hand bolts 214 extending up from the bottom side of the camera platform 200 are used to attach the camera 60, or an adapter plate, to the camera platform 200.

[0082] Referring back to Fig. 1, typically control, signal, power, and other electrical wires or cables leading to-the camera 60 and camera accessories on the head 50 extend back up on or through the crane arm 40, to the dolly, mobile base, or other mobile support. These electrical lines allow the camera operator to remotely operate the camera and to view (e.g., on a remote monitor) the images recorded by the camera. The motors which control movement of the head, i.e., the pan motor 86, the tilt motor 136, and the roll motor 166 also require electrical connections for power and control.

[0083] Generally, the pan, tilt and roll housings have similar or identical components, and they operate the same way. Figs. 20 and 21 show enlarged views of the roll housing 160. However, the details shown in Figs. 20 and 21 typically apply as well to the pan and tilt housings as well. To make the camera head 50 waterproof or water resistant, the housing 160 is sealed. As shown in Fig. 20, the roll shaft 162 is rotatably supported on a first or outer bearing 244 and a second or inner bearing 245. A shaft seal 246 seals against the roll shaft 162 against the housing 80, while allowing the shaft to rotate. A second or inner- shaft seal or O-ring 237 similarly seals the shaft 162 against the inner end of the housing 80. A bearing seal or O-ring 238 seals off the inner end of the housing and the inner bearing 245.

[0084] Referring still to Figs. 20 and 21, a tube fitting or nipple 89 is joined to or part of a plate 230. Screws passing through the plate, and the outside of the slip ring assembly 168, attach them to the housing 80.. O-rings 234, 235, and 236 seal the plate 230 and the slip ring assembly 168 to the housing. A plastic or rubber tube 243 is attached to the nipple. As shown in Fig..1, a control and power cable 250 linked to the camera 60 extends from the crane arm 40 to a tube fitting 89 on the pan housing, and from there to tube fittings 89 on the tilt and roll housings. The cable 250, or wires leading to the control cable, are contained within segments of the tube 243. The wires make a rotatable connection in each slip ring assembly (with the roll axis slip ring assembly 168 shown in Figs. 20 and 21). The wires then extend through the shaft 162 (or the shafts 82 or 132), through a shaft plug 240, and then out of the housing 160 (or housing 80 or 130), within another section of the tube 243.
The shaft plug 240 is sealed against the shaft by O-rings 242. Consequently, both the housing and the electrical connections are sealed.

[0085] To allow for quicker set up or configuration changeover, three pairs of waterproof connectors are provided. A first pair of connectors 252 is mounted on the pan frame 70, a second pair 254 is mounted on the tilt frame 72, and a third pair 256, as shown in Fig. 10, is mounted on the roll frame 74.
Routing the electrical lines through the connectors allows the frames to be removed and replaced as desired, or conversion between two and three-axis operation, without the need for separate handling of the electrical lines or wires. As the slip ring assemblies, connectors, wiring, and motors are sealed, the entire head 50 can be submerged, as shown in Fig. 1, without detrimental loss of performance or reliability.

[0086] Referring to Fig. 23 which shows the details of the connector pairs 252, 254, and 256, a first end cover having a first hose adapter or fitting 282 is attached (via screws) to a female housing 270. A locking collar 274 captive on the female housing 270 threads onto a male housing 286. A female half-coupling 276, and male half-coupling 278, and a compactor allow the male and female housings to be joined into a watertight connection.

[0087] A second end cover 284, having second and third hose fittings 280 and 283 is similarly attached to the end of the male housing 286. End covers 290 and 284 are secured over and around the hose fittings. A bracket 288 attached to the male housing 278 allows the connector pair to be easily attached to a flat surface on the pan, tilt, or roll frames. O-rings 292 and 296, and a packing 298, seal the hose fittings 282, 283, and 280 to the male and female housings 286 and 270. An O-ring 294 seals male half-coupling 278 to the male housing 286. This design as shown in Fig. 23 provides a waterproof connector pair, allowing for submerged operation of the camera head 50, and also providing a quick disconnect feature for electrical lines or wires running to the camera and camera accessories on the head, and/or for the electrical motors or other electrical components of the camera head itself.

[0088] Accordingly, new and dramatic camera movements, not previously readily achievable, can now be performed. For example, using the crane arm 40 and the head 50, the camera 60 can follow an action sequence beginning on land, and then moving, without interruption, into an underwater environment, such as a swimming pool, lake, etc. In addition, the head 50 can be used in wet or rainy environments, without taking protective steps, such as draping or wrapping, since the head 50 is largely impervious to water.

[0089] As shown in Figs. 4, 8, and 17, the head 50 has various hollow interior spaces. Each space is provided with purge gas ports 226.

[0090] By purging the interior spaces with dry nitrogen gas, the need for painting, plating, or otherwise finishing the internal surfaces of the head 50 is avoided, and internal corrosion is reduced or eliminated. As the head 50 is modular and has no covers, it can be quickly and easily serviced.

[0091] As shown in Fig. 19, an extension or spacer 260 can be installed in-between the pan frame 70 and tilt frame 72, or between the tilt frame 72 and the roll frame 74, to expand or enlarge the camera head 50, for holding unusually large or bulky cameras and/or camera accessories. A similar extension may be installed to effectively lengthen the connecting tube 144 of the tilt frame, shown in Fig. 6, or to lengthen the tube 154 or extension 158 of the roll frame 74, shown in Figs. 3, 4, and 10.

[0092] While the drawings show a three-axis camera head, the same designs described above may also be used in a two-axis camera head. In the two-axis design, the tilt arm assembly 153 is removed and the camera platform 200 is attached directly to the tilt shaft 132.

CAMERA HEAD SETUP

[0093] In use, the head 50 is mounted on a camera crane 40 or other support such as a vehicle,, overhead cable trolley, etc. The overall size or envelope of the camera head 50 is adjusted, as desired, to meet the clearance space requirements of the camera and camera accessories by releasing the cam locks 220, appropriately positioning the tilt frame 72 and the roll frame 74, and then engaging or locking the cam locks 220. The camera is mounted onto the camera platform 200. Appropriate electrical connections are made via the connector pairs 252, 254, and 256 through the slip ring assemblies 88, 138, and 168. The camera head 50 is then balanced, using known techniques. For example, movement about the pan and tilt axes is locked out by engaging the stop pins 90 and 140. The camera is then balanced about the roll axis R.

Next, rotational movement about the pan and roll axes is locked out via the locking or stop pins 90 shown in Figs. 6, 11, and 22, and 170 shown in Figs. 4 and 7, while the camera head 50 is balanced about the tilt axis T. The camera head 50 is then balanced about the pan axis P, in a similar way, via preventing rotational movement about the roll axis R and the tilt axis T, using the stop pins 140 and 170.

[0094] The camera head 50 provides several advantages. It can be used underwater, or in wet environments, since all bearings, motors, and electrical components and fittings are waterproof or sealed. Movement of the camera head 50 in three axes can be remotely controlled via electrical signals to the motors. Alternatively, the motors and gears can be quickly disengaged from the frames via the cam levers 98, for manual or hand control or positioning of camera movement about any of the pan, tilt, or roll axes. Even without disengaging the motors, the frames can be forcibly moved manually, as the gears 84, 134 and 164 can back drive the worm gear 110, before the clutch 102 slips, if sufficient force is applied.

[0095] The camera head 50 is also compact and lightweight.
Accordingly, it can be used in confined spaces. It can also be mounted on smaller and lower load carrying capacity crane arms. As a result, filming shots or sequences can be achieved with overall more compact, lightweight, and more maneuverable and transportable equipment. The camera head 50 is also highly reliable, as it has a simplified design (in contrast to other camera heads) and it is largely sealed against water, dust, dirt, etc. The camera head 50 is also highly adaptable and can be set up to hold cameras and accessories ranging from small compact digital video cameras, to large conventional film cameras, -along with associated lenses, film magazines, batteries, and other camera accessories.

CAMERA HEAD STABILIZATION SYSTEM

[0096] As shown in Fig. 24, a camera 432 having a lens 434 is supported on a camera stabilization system 430 at the front end of an arm 426 of a camera crane 420. The camera crane arm 426 is pivotably supported on a mast 424 on a mobile base 422. Fig. 24 accordingly shows one example of the use of the camera stabilization system 430 with a camera 432. The stabilization system 430 may also be used on various other types of platforms or supports, including camera cars, camera trucks, camera dollys, aircraft, watercraft, and virtually any other vehicle, base or support where stabilization is desirable.

GIMBAL DESIGN

[0097] Turning now to Figs. 25 and 26, the support system 430 includes a pan frame 450 preferably formed as a hollow arcuate or curved box section.
A pan shaft 452 is rigidly attached (e.g., welded, bolted or pinned) to a front support plate 428 of the camera crane 420 or other support vehicle or structure. The pan frame 450 can pivot or rotate on the pan shaft 452 about a pan axis 451, as shown in Fig. 25.

[0098] Referring still to Figs. 25 and 26, a dutch or roll frame 454 is attached to a roll collar 490 having a roll shaft 456 extending into the lower end of the pan frame 450. The roll frame 454 is pivotable or rotatable about a roll axis 455 shown in Fig. 26. The roll frame 454 preferably includes a parallelogram linkage 488 having first and second parallel links 492 and 494.
The back ends of the links 492 and 494 are attached to the roll collar 490 with locking bolts 486. Similarly, the front ends of the roll links 492 and 494 are attached to a tilt collar 500 with locking bolts 486. The locking bolts 486 are loosened during balancing or set-up, to properly position the roll frame 454.

The locking bolts 486 are then tightened, at four places, to provide a rigid connection between the roll collar 490 and the tilt collar 500. The roll frame 454 requires no other internal or external components, such as springs, dampeners, etc.

[0099] Referring still to Figs. 25 and 26, a tilt frame 458 has a tilt shaft 460 extending into the tilt collar 500. The tilt frame 458 is pivotable about a tilt axis 459, shown in Fig. 25. Referring to Fig. 25 and momentarily to Fig. 31, the tilt frame 458 includes an L-shaped camera platform 462. The camera 432 is secured onto the platform 462 via standard screws or bolts. The vertical leg of the camera platform 462, as shown in Fig. 31, extends through a sleeve 464 joined to the tilt collar 500. The vertical position of the camera platform (and of the camera 432) can be adjusted by loosening sleeve bolts 466, vertically positioning the camera platform 462 as desired and then tightening the sleeve bolts 466.

[00100] Referring now in addition to Figs. 27, 28, and 29, a pair of drive motor assemblies 472, 474 is provided to drive the pan frame 450, the roll frame 454, and the tilt frame 458. While the six drive motor assemblies used in the system 430 are preferably the same, to provide a more clear description, each of the motors is separately referred to and numbered based on its location and function in the system 430. Referring momentarily to Fig. 38, a drive motor assembly 475 includes an electric motor 476 which drives an output gear 479 through a speed reducing gear train 478.

[00101] Referring to Figs. 25, 26, and especially Fig. 29, the pan shaft 452 is preferably fixed in place (e.g., bolted, welded, etc.) on the support plate and does not pivot or rotate. A pan shaft gear 470 is rigidly attached to or part of the pan shaft 452. The pan shaft gear 470 is preferably located within the pan frame 450, although it may also be external. The pan frame 450 is rotatably supported on the pan shaft 452 via bearings. First and second pan motor assemblies 472 and 474 are attached to the outside of the pan frame 450. The output gear 479 of each of the pan motor assemblies 472 and 474 engages or meshes with the pan shaft gear 470. Consequently, the electric motors 476 of the pan motor assemblies 472 and 474 are positioned to exert torque on the pan frame about the pan axis 451.

[00102] A similar design is provided for rotation about the dutch or roll axis 455 and the tilt axis 459. As shown in Figs. 26 and 28, the dutch or roll shaft 456 is rotatably supported via bearings to the lower end of the pan frame 450.

A roll shaft gear 480 is fixed to the pan frame 450. First and second roll axis motors 482 and 484 are attached to the outside of the roll collar 490. The output gear 479 of each of the roll axis motors 482 and 484 is engaged with the roll shaft gear 480. Consequently, the roll axis motors 482 and 484 are positioned to exert torque on the dutch or roll frame 454 about the dutch or roll axis 455.

[00103] In a similar way, as shown in Fig. 29, the tilt axis shaft 460 is rotatably supported on bearings in the tilt collar 500 at the front end of the roll frame 454. A tilt shaft gear 502 is irrotatably attached to the tilt collar 500.

First and second tilt motor assemblies 504 and 506 are attached to the outside of the tilt collar 500. The output gear 479 of each tilt motor 504 and 506 meshes with the tilt shaft gear 502. Consequently, the tilt motors 504 and 506 are positioned to exert torque on the tilt frame 458 about the tilt axis 459.
Each of the motor assemblies described 472, 474, 482, 484, 504, and 506 is preferably the same as the motor assembly 475 shown in Fig. 38. The positions of the motor assemblies and gears, whether inside or outside of the frames, is immaterial to the invention and may be selected based on design choice.

[00104] Referring to Fig. 26, by locating the dutch or roll axis motors 482 and 484 on the dutch collar 490, the stabilization system 430 is made more compact and lightweight. As the weight of the system 430 is reduced, it has less inertia. This reduced inertia reduces the torque requirements of the stabilization system. Consequently, the system 430 can have smaller motors, use less electrical power, have less friction, and provide more accurate stabilization. In addition, the placement of the motors 472, 474, 482, 484, 504, and 506 close to the axis of rotation 451, 455, and 459 reduces the angular moment of inertia of the pan frame 450, dutch or roll frame 454, and tilt frame 458, also providing for rapid stabilizing movements.

[00105] Preferably, the motor assemblies are powered and controlled by cables or wires extending back from the stabilization system 430 to an electronics box 442 containing circuitry and a power supply. A control panel or box 440 is connected to the electronics box 442 preferably via cables.
Alternatively, wireless connections may be used. If desired, slip rings and/or slip-type electrical connectors or fittings can be used to minimize wind-up of the cables.

[00106] As shown in Figs. 27, 28, and 29, to prevent excessive wind-up of the cables, a stopping or limiting mechanism 512 is provided within the system 430 about each of the axis. Typically, the limiting mechanism 512 will allow e.g., only two or three complete 3600 revolutions. The limiting device 512 typically includes several interlocking rings, as is well known in the art. A
locking device 514 is also provided for each axis. The locking mechanism 514 is used during storage, shipment, set-up or calibration and locks each of the frames into a zero (or other preset) angle position. The locking mechanisms 514 are generally disengaged when the system 430 is in use.

[00107] Figs. 24-31 show the mechanical design of the system 430 providing various advantages. Figs. 32-37 show electronic and control designs. While these designs are preferably used in the system 430 shown in Figs. 24-31, they can also be used in many other types of camera stabilization systems. Conversely, the system 430 shown in Figs. 24-31 may be used with any of the circuits, features, or control modes shown in Figs. 32-36, or it may be used with existing control systems.

MANUAL AIMING SYSTEM

[00108] Referring to Fig. 35, a camera stabilization system or subsystem 530 includes a manual aiming mode. An adder, mixer, or summator 522, manual control circuit 532, amplifier 524, and sensor 526 is provided in each separate circuit 550, 552 and 554 for control of movement about each of the pan, roll, and tilt axis 451, 455, and 459. The sensor 526 is preferably a rate sensor. Referring to Fig. 35, .a separate input control device 520 associated with each of the pan, roll, and tilt axis circuits 550, 552, and 554, provides an input signal to the summator 522. The input control device 520 may be a joystick, control wheel, pedal, mouse, etc.

[00109] Referring to Fig. 36, the manual aiming circuit 532 is shown within the dotted lines. For the control circuit 550, 552, and 554 associated with movement about each axis 451, 455, and 459, a switch 534 has on and off positions. In the off position, shown in dotted lines in Fig. 36, the manual aiming circuit 532 is disconnected or inactive, and each of the circuits 550, 552, and 554 operates using traditional feedback control. With the switch 534 in the on position, as shown in solid lines in Fig. 36, the manual aiming circuits 532 are active. Each' of the manual aiming circuits 532 includes a variable resistor 538 forming a divider 536. A capacitor 542 in combination with a second variable resistor 544 forms a differentiator 540. The outputs from the divider 536 and differentiator 540 are added in a manual aiming summator 546. The output from the summator 546 is provided to the amplifier 524. The design of the manual aiming circuit 532 in each of the three axis circuits 550, 552, and 554, are preferably the same.

[00110] In use, the switch 534 is switched to the on position, shown in Fig.
36, when the camera operator wants to manually aim the camera 432. This is a common event in film and video production. The camera operator will often want to manually aim the camera (by grabbing and moving the camera platform or the camera itself), for various reasons, such as checking or monitoring a camera angle, field of view, etc. Traditional camera stabilization systems act to resist this type of manual movement, because such intended movement via the hands of the camera operator are indistinguishable from unintended camera movement caused by inertial or gravitational forces associated with movement of the camera crane, motion base, or vehicle supporting the camera, wind loads, etc. With existing systems, when the manual aiming force applied by the camera operators hands exceeds the maximum torque output of the motors, the camera platform suddenly breaks free and can be manually aimed.

[00111] This results in an abrupt jerky movement which often overshoots the desired position, with additional time consumed in achieving the desired camera position. Alternatively, the stabilization system can be switched off entirely before manual aiming. However, in either case, smooth camera movement, in a manual mode, is difficult or impossible to achieve. Existing camera stabilization systems either interfere with manual aiming, by automatically resisting such movements until torque' limits are exceeded, or, when they are switched off entirely, provide no beneficial control characteristics, with the camera platform moving entirely in response to whatever forces (inertial, gravitational, wind, hand, etc.) may be instantaneously acting on the camera platform. These effects result from the fundamental basic conflicting objectives between a camera stabilization system, which attempts to keep the camera lens aimed at a desired position, regardless of external influences, and manual aiming where the camera operator wants to simply aim the camera manually without interference.

[00112] Referring to Figs. 35, 36, and 37, the divider 536 provides adjustable dampening, and the differentiator 540 provides an adjustable inertia feel, to manual camera aiming movement. Accordingly, the manual aiming circuit 532 provides electronically adjustable inertia and dampening for camera movement in each of the three axes, with inertia and dampening separately adjustable in each axis. Of course, these features may also be used only on a single axis, or on two axes. If all three circuits 550, 552 and 554 are used, they can be individually switched on and off as needed.

[00113] Fig. 37 shows an electronics box 442 for use with the manual aiming system 530. Hand controls, such as joysticks on the control box 440, are connected to the electronics box 442. Alternatively, the electronics box and control box 440 may be combined into a single unit, with e.g., joysticks mounted directly on the combined box, as shown in Fig. 35. However, preferably the electronics box 442 is a separate unit provided with inputs from a control panel or box 440 or other remotely located control devices, such as joysticks, wheels, pedals, a mouse, or recorded playback media (tape, CD, etc.). The switches 534 can be separately and independently switched on or off, to provide manual or automatic control. When used, dampening and inertia are preferably adjustable via knobs, dials, etc. 539 and 540 on the control box 440. With the manual aiming circuit 532 switched on, the system 530 provides an adjustable inertia feel to the camera platform. Manual aiming movement of the platform is resisted by the motor assemblies 475 in a way to provide an inertia feel to the camera platform. The circuit 532 controls the motor assemblies 475 based on feedback from the rate sensors 526, in a way so that the camera platform responds to external forces as if the camera payload has a much greater apparent inertia. As a result, during manual aiming, if the inertia levels are turned up using the differentiator 540, even large forces acting on the camera platform will produce slower and smooth movements. This provides for smoother camera platform movement during manual aiming. Similarly, the divider 536 provides adjustable dampening to movement of the camera platform, much like hydraulic dampening, helping to provide smooth camera platform movement even during manual aiming.

[00114] In the manual aiming circuit 532, the divider 536 provides control of the motor assemblies 475 to provide resistance to camera platform movement which is proportional to the speed or rate of camera platform movement, i.e., dampening. The differentiator 540 in the manual aiming circuit 532 controls the motor assemblies 475 so that they provide a resistance to camera platform movement which is proportional to acceleration of the camera platform, as detected by the sensors 526 (i.e., inertia). Consequently, to the camera operator, the camera feels and reacts as if the camera is supported on a fluid mounting head.

DRIFT COMPENSATION

[00115] Camera stabilization systems typically use sensors on the camera platform for sensing rate or angular speed. These are typically fiber optic rate sensors. Due to slight inaccuracies in operation of the sensors, virtually all stabilization systems have some degree of drift. Drift is unintentional movement of the camera platform over time. Consequently, over longer periods of time, for example, one hour, the camera position can drift or move, even though. the. stabilization system is operating properly. As a result, if there is a significant delay in filming or video recording (for example, a lunch break), the camera may drift out of position. If unnoticed, this can result in errors when filming resumes. If the drift of the camera is noticed, it must then be corrected by repositioning the camera. In either even, drift can result in costly loss of production time.

[00116] Referring to Fig. 33, a control system 560 is provided for reducing or eliminating drift. The system 560 includes 3 separate circuits 562, 564, and 566, for controlling drift movement in each of the pan, roll and tilt axes, similar to the system described above in connection with Fig. 35. As shown in Fig.
33, the camera stabilization system with drift control 560 uses conventional gyrostabilization techniques, to provide the stabilization function.
Specifically, a rate sensor 526 on the camera platform provides an output to a summator 570. Outputs from trim potentiometers 528 and from a control device 520 are also input to the summator 570. The sum output from the summator 570 is amplified by an amplifier 524 which drives a motor assembly 475, or pair of motor assemblies. This provides feedback gyrostabilization of the camera 432.

[00117] To reduce or prevent drift, as shown in Fig. 33, a second sensor 568 is provided to detect movement about each axis. The sensor 568 is a position sensor. For example, the sensor 568 may be an infrared reflective sensor mounted on the pan frame 450 and facing the pan shaft gear 470. In this way, the sensor 568 facing the teeth of the gear 470 can optically detect incremental movement. The output from the drift position sensor 568 is provided into the drift compensation summator 570, and adds to the signals from the control device 520 and trim potentiometer 528. Consequently, the system shown in Fig. 33 having both a rate sensor 526 and a position sensor 568 associated with each pivot axis, is able to provide stabilization and drift control or drift compensation.

[00118] The drift position sensor 568 for detecting drift in the roll axis is preferably supported on the roll collar 490 and detects movement optically via the presence or absence of reflected light from the roll shaft gear 480.
Similarly, the drift position sensor 568 for detecting drift in the tilt axis is preferably supported on the tilt frame 458 and detects movement optically relative to the tilt shaft gear 502.

PAN CONTROL WITH TILT SPEED CORRECTION

[00119] Referring to Fig. 34, as the camera platform is pivoted about the roll axis 455, the rate sensor 526 for the pan axis 451 requires trigonometric compensation, since the sensor 526 is no longer horizontal. For example, if the system 430 is positioned as shown in Fig. 26, the pan axis 451 is parallel with the tilt axis 459. In this position, if the camera operator, using a joystick 520 tries to make a panning movement (i.e., to have the pan frame 450 pivot about the pan axis 451), the tilt axis sensor will detect this movement as an unintended deviation from the desired lens position. The system will therefore automatically compensate by pivoting the tilt frame by an equal an opposite amount. The end result is no change in the lens angle, because the manual control of the pan frame is cancelled out by the automatic control of the tilt frame. With the roll frame at any angular position between zero, as shown in Fig. 25, and 90 degrees, as shown in Fig. 26, the same cancelling of manual pan movement also occurs, although to a lesser extent. For example, with the tilt frame at an angle of 30 degrees (e.g., from horizontal), automatic movement of the tilt frame will be opposite to and one half of pan movement sine 30 = 0.5 ) as input by the camera operator. In the past, achieving desired manual pan movement, against the automatic counteracting movements of the tilt frame, has been left up to the camera operator (via simultaneous manual control of the tilt frame). However, this makes camera operator's job even more difficult. As shown in Fig. 34, a compensated control circuit 580 is provided to overcome this longstanding disadvantage. An output from a roll angle sensor 582 senses the sine roll angle and provides it to a multiplier 584.
The pan axis control signal is also provided to the multiplier 584. The output from the multiplier 584 is provided to a correction summator 586, along with the outputs of the tilt axis control device 520 and the tilt axis sensor 526.
Accordingly, the output of the sensors 526 is compensated when the camera platform on which the sensors are mounted is positioned at a non-zero roll angle. As a result, regardless of the angular position of the roll frame, all of the frames and the camera pan together.

AUTOMATIC LEVELING SYSTEM

[00120] With existing camera stabilization systems, in general, a signal from a level sensor on the camera platform provides a reference causing the camera platform to return to level or horizontal, whenever the control signal from the control 520 is zero. For example, if the input control device 520 is a joystick, when the joystick is released and returns to center, the level sensor signal causes the camera platform to return to a zero position about the roll axis. However, the camera operator may want the camera to remain at a non-zero roll angle, even with the control device 520 released and at a zero position.

[00121] In addition, if the camera platform is accelerated or decelerated, e.g., at the end of a swinging crane arm, the level sensor signal will not accurately return the camera platform to the zero roll angle, due to inertial effects.

[00122] Referring to Fig. 32, an automatic leveling system 590 is provided having three modes of operation. The modes of operation are selected using a control panel 440. In the off mode, the system 590 operates using existing techniques. When the control device 520 is moved to a zero or center position and has a zero output, the camera platform remains in whatever roll or dutch angle it is in. In the normal mode of operation, the system 590 operates as described above. That is, when the control device 520 has a zero output (for example, a joystick released), the leveling circuit 596 causes the roll axis motor(s) assembly 475 to return the camera platform to a zero roll angle.

[00123] In the fast mode, when the control device 520 has a zero output, the leveling circuit 596 (a switchable/separable amplifier) causes the roll axis motor assemblies 475 to very rapidly return the camera platform to a zero roll angle or horizontal. The fast mode is preferably engaged with a push button, to rapidly level the camera about the roll axis. As shown in Fig. 32, in addition to the roll axis rate sensor 526, there is also a second sensor 595 for sensing position or inclination. In the fast mode, the leveling circuit 596 provides an output which rapidly brings the camera to horizontal (e.g., at 10 degrees/second), about the roll axis, whenever the output signal from the inclination sensor is above a minimum threshold. When the inclination sensor output is below the threshold value, but is not zero, (typically with the inclination sensor sensing an inclination angle or 1,2,3,4 or 5 degrees) the circuit 596 steps down to a second and slower levelling rate, such as '/2 degree/second, to avoid overshooting.

GIMBAL BALANCING

[00124] Referring to Figs. 25-31, the term gimbal refers to the mechanical linkage of the pan, roll and tilt frames and their interconnections. In use, the camera 432 is attached to the tilt frame 454. The vertical position of the tilt frame 454 is adjusted as desired by positioning the vertical or upright arm of the tilt frame 458 in the sleeve 464 and tightening the sleeve bolts 466. The camera is then balanced side to side or laterally on the tilt frame and locked into position via the bolts 465 shown in Fig. 31. Balancing is continued by loosening the roll frame locking bolts 86 and then moving the tilt frame 458 carrying the camera 432 side to side, until there is zero torque acting about the roll axis 455. The roll collar 490 and roll frame 454 are then pivoted 901, from the position shown in Fig. 25 to the position shown in Fig. 26. The center of gravity of payload, i.e., the camera 432 is then again moved from side to side until zero torque results about the roll axis 455. The locking bolts 486 are then tightened.

[00125] The camera 432 can then be stabilized using any of the systems, circuits, and techniques described above in connection with Figs. 32-37.
Alternatively, existing known circuits may be used.

[00126] In comparison to previous types of systems, the system 430 shown in Figs. 24-31 provides improved convenience in balancing, has fewer pinch points providing increased safety in use, and is more compact and lightweight.

[00127] Referring to Fig. 38, the motor assemblies 475 have gear trains 478 including conical bevel gears. The motor assemblies 475 are compact, to reduce the moments of inertia of the frames supporting them, and to provide a compact design. For providing movement about each axis, the pairs of motors operate on offset amplified signals. The drive signal to each motor is the same, although they are offset from each other. This provides for a linear system and reduces or avoids backlash.

[00128] By locating the pan axis motors 472 and 474 on the pan frame 450, and by locating the roll axis motors 482 and 484 on the roll frame 454, the system 430 is made more compact and with less moment of inertia. This allows for more rapid movements. The system 430 is also accordingly more aerodynamically balanced. Consequently, there is less wind load on the system.

BLOCK SWITCHING

[00129] During balancing, all motors must be turned off. Accordingly, each time the payload changes, for example, by changing a lens on the camera, power to all motors must be turned off and the system rebalanced.

Accordingly, a block power switch 600 controlling power to all motors is preferably provided near the camera, e.g., on the pan frame 450. This allows the assistant camera operator to conveniently turn off power to the motors for balancing. The block power switch 600 preferably controls only power to the motors, and not to the circuitry or sensors.

[00130] The words pan, tilt or roll in the claims refers to the axis associated with the element, and is not a description of any characteristic of the element itself. The words pan, tilt and roll have their usual meanings, as understood in the field of making motion pictures. However, they can equivalently be replaced by first axis, second axis and third axis, where the invention is used in non-traditional motion picture applications.

Claims (10)

CLAIMS:

1. A camera head comprising:
a first frame;

a first arm rotatably attached to the first frame;

a first motor for rotating the first arm relative to the first frame, with the first motor enclosed within a sealed first housing;

a second frame attached to the first arm;

a second arm rotatably attached to the second frame;

a second motor for rotating the second arm relative to the second frame, with the second motor enclosed within a sealed second housing;

a first shaft rotatably supported within the first housing, with the second frame attached to the first shaft, and the first shaft sealed against the first housing, a first gear linked to the first shaft through a first clutch, and with the first gear linked to the first motor, and one or more clutch drive pins sealed against the first housing, and moveable from a first position, wherein the first motor drives the first shaft through the first clutch, to a second position, wherein the first shaft can rotate free of the motor.

2. The camera head of claim 1 further comprising a third frame, a third arm rotatably attached to the third frame, and a third motor for rotating the third arm relative to the third frame, with the third motor enclosed within a sealed third housing.

3. The camera head of claim 1 wherein the first and second sealed housings are waterproof, to allow for underwater operation of the camera head.

4. The camera head of claim 1 further comprising a position locking device moveable from a locked position, wherein the locking device prevents movement between the first arm and the second housing, to an unlocked position, wherein the second housing can move relative to the first arm, to adjust the size of the camera head.

5. A remote camera head comprising:
a first frame;

a first sealed housing on the first frame;

a first arm rotatably attached to the first frame;

a first motor for rotating the first arm relative to the first frame, with the first motor enclosed within the first sealed housing;

a second frame attached to the first arm;

a second sealed housing on the second frame;

a second arm rotatably attached to the second frame;

a second motor for rotating the second arm relative to the second frame, with the second motor enclosed within the second sealed housing;

a first hollow shaft rotatably supported within the first sealed housing, with the second frame attached to the first shaft, and the first shaft sealed against the first sealed housing;

a first gear linked to the first shaft through a first clutch, and with the first gear linked to the first motor;

a first slip ring assembly extending into the first hollow shaft;

a first shaft plug within and sealed against the first hollow shaft;

a first electrical cable extending into a first end of the first slip ring assembly via a waterproof connection; and a second electrical cable extending through a waterproof connection in the first shaft plug and into a second end of the first slip ring assembly.

6. The camera head of claim 5 further comprising a tube adapter having a tube nipple and a base plate, with the tube adapter attached to the first slip ring assembly and to the first housing, first seal sealing the base plate to the first slip ring assembly, and a second seal sealing the slip ring assembly to the first housing, to provide a waterproof connection for wires leading into the first slip ring assembly.

7. A camera support comprising:

a first housing having a first interior sealed space;

a first purge gas port on the first housing connecting into the first interior sealed space, for delivering a purge gas into the first interior sealed space;

a first motor supported by the first housing;

a second housing having a second interior sealed space, and with the second housing linked to the first motor for rotational movement of the second housing relative to the first housing about a first axis;

a second motor supported by the second housing;

a second purge gas port on the second housing connecting into the second interior sealed space, for delivering a purge gas into the second interior sealed space;

a third housing linked to the second motor for rotational movement of the third housing relative to the second housing about a second axis substantially perpendicular to the first axis; and a lock pin moveable between a lock position, where the lock pin extends between the first housing and the second housing, to prevent movement between them, and an unlock position, wherein the lock pin is withdrawn from one of the first and second housings, to allow rotational movement between them.

8. The camera support of claim 7 with the second housing linked to the first motor by a first arm, and with the second housing securable onto the first arm at multiple positions on the first arm, and with third housing linked to the second motor by a second arm, and with third housing securable onto the second arm at multiple positions on the second arm.

9. The camera support of claim 7 further comprising an adjustable brake to set braking force against rotation of the second housing about the first axis.

10. A camera support comprising:

a first housing having a first interior sealed space;

a first purge gas port on the first housing connecting into the first interior sealed space, for delivering a purge gas into the first interior sealed space;

a first motor supported by the first housing;

a second housing having a second interior sealed space, and with the second housing linked to the first motor for rotational movement of the second housing relative to the first housing about a first axis;

a second motor supported by the second housing;

a second purge gas port on the second housing connecting into the second interior sealed space, for delivering a purge gas into the second interior sealed space;

a third housing linked to the second motor for rotational movement of the third housing relative to the second housing about a second axis substantially perpendicular to the first axis;

a first shaft rotatably supported within the first housing, with the second housing attached to the first shaft, and the first shaft sealed against the first housing, a first gear linked to the first shaft through a first clutch, and with the first gear linked to the first motor, and one or more clutch drive pins sealed against the first housing, and moveable from a first position, wherein with first motor drives the first shaft through the first clutch, to a second position, wherein the first shaft can rotate free of the motor.