EP0058675A1

EP0058675A1 - Gyro mounting system for stabilized platforms

Info

Publication number: EP0058675A1
Application number: EP19810901929
Authority: EP
Inventors: Dorsey T. Smith; Albert H. Bieser
Original assignee: Be Industries Inc
Current assignee: Be Industries Inc
Priority date: 1980-08-25
Filing date: 1980-08-25
Publication date: 1982-09-01
Also published as: WO1982000709A1

Abstract

Des gyroscopes de roulis et de tangage (26, 27) de stabilisation de plate-formes sont montes sur la plate-forme (12) et couples ensemble de maniere a effectuer un mouvement synchrone de rotation autour des axes (28, 29) de leurs rotors respectifs par rapport a la plate-forme stable (12). Un enroulement (10) electrique de connexion est "deroule" par rapport a une condition d'enroulement trop serree ou trop lache en tournant la plate-forme stable (12) avec les gyroscopes (26, 27) de roulis et de tangage couples a la plateforme de base (22) permettant au gyroscope de maintenir leurs orientations relatives l'un par rapport a l'autre et par rapport a la plate-forme de base (22) pendant les rotations de la plate-forme stable (12).Roll stabilization and pitch gyroscopes (26, 27) for platform stabilization are mounted on the platform (12) and couples together so as to perform a synchronous rotational movement around the axes (28, 29) of their respective rotors relative to the stable platform (12). An electrical connection winding (10) is "unwound" in relation to a winding condition that is too tight or too loose by rotating the stable platform (12) with the gyroscopes (26, 27) of roll and pitch coupled to the base platform (22) allowing the gyroscope to maintain their relative orientations with respect to each other and with respect to the base platform (22) during the rotations of the stable platform (12).

Description

Description Gyro Mounting System for Stabilized Platforms

Technical Field

This invention relates in general to platform stabilizing systems and, more particularly, to passive gyro platform stabilization systems wherein there is periodic requirement to unwind or "untwist" electrical leads providing connections between the cable platform and its base platform .

Background Art

Commercial satell ite tracking systems for communication and other commer cial or military equipments requiring relatively inexpensive less than high precision stable platform systems for the mounting of antennas, camera and the like have mode passive gyro platform stabilization systems increasingly popular. Several examples of systems of this type are shown in U .S . Patents Nos . 3,893, 123; 4,020, 491 and 4, 193, 308,. in which the inventors herein are inventors or co-inventors . Difficulty in systems of these types and others occurs when the stable platform in normal use has progressed too far in one azimuth direction causing the electrical leads providing connection between the stable platform and the base platform to be wrapped around the platform support post to the l imit of their length . To return the wiring to its correct position, the stabilized platform must be "unwound" . However, relatively rapid rotation of the stable platform in azimuth to unwind the wiring of prior art systems can cause "tumbl ing" of the gyros and instability of the platform .

Disclosure of Invention

It is, therefore, a principal object of the present invention to provide a gyro stabilized platform which can be driven in relatively rapid azimuth rotation to unwind wiring without "tumbling" the gyros.

Another object is to provide a gyro stabilized platform wherein wiring between the stable plotform and the base platform can be unwound without disturbing the stability of the gyros or the stable platform . Features of this invention useful in accomplishing the above objects include the mounting of each of the rol l and pitch gyros of the stable platform on bearings for rotational movement relative to the stable platform centered on the rotor axis of the gyro. The roll and pitch gyros are interconnected for synchronous rotational movement to assure that their precession axes are maintained in orthogonal relationship . Provision is mode to selectσbly odd to the gyro synchronous interconnect system a connection to the base platform whereby the stabilized platform may be rotated without disturbing the orientation of the precession axes of the pitch and roll gyros with respect to the base platform or each other.

Brief Description of Drawings Details of the invention are described in connection with the accompanying drawings in which: Figure 1 is a side elevation showing a stabilized platform antenna system according to the present invention mounted on a base platform; Figure 2, a partially in section and partially broken away, taken along line 2-2 of Figure 1; and Figure 3 is a view taken along lines 3-3 of Figure 2 and illustrating the synchronized rotational interconnection of the gyros with each other and with the base platform.

Best Mode for Carrying out the Invention

Referring to the drawings, there is shown for illustrative purposes in Figures 1 and 2 a reflector antenna 1 1 mounted on a stabilized platform 12. The antenna is motor driven to pivot on the stable platform 12 about an elevation axis 13 on axle and bearing assemblies 14. The stable platform 12 is mounted for azimuth rotation about axis 15 through platform hub 16 and bearings 17 and 18 to spindle shaft 19. Spindle shaft 19 is supported on shaft 50 of the pedestal 20 by universal connection of gimbal joint 21 . Pedestal 20 is affixed to the base platform 22 which may be a ship, for example. The stable platform 12 may be driven in czimuth rotation by motor 23, belt 24 and pulley 25 affixed to spindle shaft 19. All of the structure described in the foregoing is conventional .

Wiring, such as cable 10, provides necessary electrical connections between power supplies and signal transmitters on the base platform and the various motor controls and other electrical or electronic equipment mounted on the stable platform 12. In order to accommodate the rotational freedom necessary for the stable platform wiring 10, (brought up through hollow pedestal 20), after emerging from the pedestal 20 is very loosely wrapped around shaft 50 before being 0 clamped to the stable platform, from which point it is distributed to its various connections. The loop of cable 10 about shaft 50 is loose enough to al low the stable platform to rotate up to between 270º to 360º counterclockwise about the pedestal 20 without the cable becoming too tightly coiled about the shaft 50. About the same degree of rotational freedom of the stable platform is provided in the opposite direction.

Mounted on stable platform 12 are gyro assemblies 26 and 27 with the rotational axes 28 and 29 of their rotors 30 and 31 , respectively, in a vertical plane. Bearings 32 and 33, by which means the frames 36 and 37 of gyros 26 and 27, respectively, are mounted to the stable platform 12 al low for azimuth rotation of each gyro assembly with respect to the stable platform 12. The gyro rotors or flywheels 30 and 31 are driven by their respective motors 34 and 35. The rotor 30 and motor 32 combination of gyro assembly 26 is pivotal ly mounted on frame bracket 38 and a similar opposing bracket (not shown) for a single degree of freedom about its precession axis 39. Likewise the rotor 31 and motor 35 combination is mounted on frame bracket 40 and a corresponding bracket (now shown) for a single degree of freedom about its precession axis 41 .

It is essential that the precession axes 39 and 41 of the gyros 26 and 27 remain in an orthogonal relationship . Therefore synchronization means is provided . In the embodiment il l ustrated, a sprocket 42 affixed to the underside of frame 36 of gyro 26 and a sprocket 43 having the same number of teeth and affixed to the underside of frame 37 of gyro 27 are interconnected by a chain 44 to provide the required synchronization .

As best shown in Figure 3, cham 44 passes around sprockets 42 and 43 as wel l as spring loaded idler 45 pivoted at 46 and idler 47 mounted for l imited pivotal movement about point 48 in response to actuation of solenoid 49. Spring loaded idler 45 keeps proper tension on chain 44 at al l times whatever the position of idler 47.

Chain 44 passes on either side of the shaft 50 of pedestal 20. A hub sprocket 51 is mounted to spindle shaft 19 above gimbal joint 21 and thus is fixed in azimuth with respect to the pedestal 20 and base platform 22 but moves about the pitch and rol l axes with stable platform 12. Hub sprocket 51 has the same number of teeth as sprockets 42 and 43.

It is the arrangement of the three sprockets 42 , 43 and 51 , chain 44, idlers 45 and 47, and solenoid 49 that al lows unwinding of the stable pl atform wiring by relatively rapid rotation of the stable platform about its vertical axis without disturbing the stability of gyros 42 and 43. As stated above, gyros 26 and 27 are maintained with their precession axes in orthogonal relationship by the arrangement in Figure 3 being shown in its normal operating condition with spring loaded idler 45 holding one side of chain 44 out of engagement with hub sprocket 51 and solenoid 49 positioning idler 47 to hold the other side of chain 44 out of engagement with the other side of hub sprocket 21 .

When it is desired to "unwind" the stable platform 12, solenoid 49 is activated to pivot idler 47 to the position shown by dashed lines in Figure 3. This action allows chain 44 to engage the teetfrof hub sprocket 51 when spring loaded idler 45 takes up the slack, as shown in dashed lines. Power is then applied to motor 23 to drive the stable platform 12 in rotation around pedestal 20 through drive belt 24 and pulley 25. As the stable platform 12 rotates about the pedestal chain 44 and sprockets 42, 43 and 51 hold gyros 26 and 27 such that their precession axes remain in the same orientation with respect to the pedestal and each other even though the gyros are moving around the pedestal with the turning of the stable platform. In this manner the cabling and connections are unwound without disturbing gyros 26 and 27.

Of course, the chain and sprocket arrangement is not the only suitable synchronizing interconnection between gyros 26 and 27, and, when required, pedestal 20. For example, timing belts and pulleys or other similar mechanisms may be used .

Al though the gyros of the stable platform are referred to herein as the "roll " gyro and "pitch " gyro, these terms are to be understood to be merely convenient terms of designation distinguishing the gyros and do not in any way designate the alignment of a gyro axis with the actual roll or pitch axis of the base platform although they may be at times so aligned.

Whereas this invention is herein illustrated and described with respect to particular embodiments thereof, it should be realized that various changes may be made without departing from essential contributions to the art made by the teachings hereof.

Claims

1 . A stabilized platform system having first and second gyros with pivotal mounting structure having pivot axis substantial ly at right angles one to the other and with each gyro rotor mounted for rotational movement about its rotor axis with respect to the stabil ized platform, means coupling said first and second gyros to each other and maintaining their precession axes in relative angular relationship, means operable to drive said stabilized platform in azimuth rotation and means selectably operable to couple said first and second gyros to a base platform mounting said stabilized platform and maintaining the relative orientation of gyro precession axes and said base platform the same during the driven azimuth rotation of said stabilized platform .

2 . The stabilized platform system of claim 1 , wherein the relative angular relationship between the precession axes of said first and said second gyros is substantial ly orthogonal .

3. The stabilized platform system of claim 1 , wherein said means coupling said first and said second gyros includes a pair of sprocket means each affixed to the frame member of one of said gyros, said sprockets having the same number of teeth and said sprockets being coupled by an encircl ing chain member engaging teeth of each sprocket.

4. The stabilized platform system of claim 3, wherein in each of said pair of sprockets is mounted to the underside of the gyro to which it is affixed.

5. The stabil ized platform system of claim 3, wherein said means selectably operable includes a third sprocket member having approximately the same number of teeth as each of said pair of sprocket means and being affixed to said base platform coaxially with said stabil ized platform and means to move said chain into engagement with the teeth of said third sprocket.

6. The stabil ized platform system of claim 5, wherein said third sprocket member is mounted to follow the pitch and rol l movement of said stabilized platform .

7. The stabil ized platform system of claim 5, wherein said means to move said chain includes an electrical solenoid. The stabilized platform system of claim 6, wherein said third sprocket member is a hub sprocket mounted with its sprocket teeth essentially coplanar with the said pair of sprocket means .

The stabilized platform system of claim 8, wherein said hub sprocket is mounted concentrically with the rotational axis of said stabilized platform above the pitch and roll axis of said platform.

The stabilization platform system of claim 9, wherein said means to move said chain includes an electrical solenoid.