US3529354A - Control system for platform having six degrees of freedom - Google Patents

Description

Sept. 1970 D. D. ROBERTS E 3,529,354

CONTROL SYSTEM FOR PLATFORM HAVING SIX DEGREES 0F FREEDOM 5 Sheets-Sheet 1 Filed April 27, 1967 D. D. ROBERTS EI'AL 3,529,354

CONTROL SYSTEM FOR PLATFORM HAVING SIX DEGREES 0F FREEDOM Sept. 22, 1910 s Sheets-Sheet 2 Filed April 27, 1967 PIC-3.5.

Sept. 22, 1970, D. o. ROBERTS ETAL CONTROL SYSTEM FOR PLATFORM HAVING SIX DEGREES OF FREEDOM Filed April 27, 1967 5 v Sheets-Sheet 3 Sept. 22, 1970 3,529,354

common SYSTEM FOR PLATFORM HAVING SIX DEGREES 0F FREEDOM Filed April 27, 1967 D. o. ROBERTS 5 Sheets-Sheet &

7 Sept. 22, 1970 p, ROBERTS ETAL 3,529,354

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United States Patent M 3,529,354 CONTROL SYSTEM FOR PLATFORM HAVING SIX DEGREES OF FREEDOM Donzil D. Roberts, Florissant, and Chung L. Feng, St. Louis, Mo., assignors to Conductron Corporation, Charles, Mo., a corporation of Delaware Filed Apr. 27, 1967, Ser. No. 634,252 Int. Cl. G09b 9/08 US. Cl. 3512 23 Claims ABSTRACT OF THE DISCLOSURE The platform of a motion base is supported by three elements which act upon a point adjacent one side of that platform and by three further elements which act upon a second point adjacent the opposite side of that platform; and each of those points can be moved in the X, Y and Z directions, and that platform can be rotated about an axis extending between those points, to provide six degrees of motion for that platform.

This invention relates to improvements in control systems. More particularly, this invention relates to improvements in motion bases.

It is, therefore, an object of the present invention to provide an improved motion base.

Flight-training equipment frequently includes a simulated cockpit of an aircraft; and it is customary to mount that simulated cockpit on the platform of a motion base to enable that simulated cockpit to assume attitudes which at least partially simulate the various attitudes which the cockpit of the corresponding aircraft can assume in actual flight. As a result, a number of motion bases have been proposed; and a number of those motion bases have been used. Many of those motion bases have been relatively slow-moving, have been wasteful of power, and have been needlessly massive. Moreover, some of those motion bases have not provided enough individually-different degrees of motion to enable the simulated cockpits mounted on the platforms thereof to even partially simulate the various attitudes which the cockpits of the corresponding aircraft could assume in actual flight. Consequently, it would be desirable to provide a motion base which could cause the platform thereof to rapidly assume any of a given number of individually-different attitudes and positions, which was economic in its use of power, and which was sturdy but of light-weight construction. The present invention provides such a motion base; and it is, therefore, an object of the present invention to provide a motion base which can cause the platform thereof to rapidly assume any of a given number of individually-different attitudes and positions, which is economic in its use of power, and which is sturdy but of light-weight construction.

The platform of the motion base provided by the present invention is supported by three elements which act upon a point adjacent one side of that platform and by three further elements which act upon a second point adjacent the opposite side of that platform; and each of those points can be moved in the X, Y and Z directions and that platform can rotate about an axis extending between those points. As a result, that platform can readily simulate forward motion, slip, roll, pitch, heave, and yawsix important degrees of motion. It is, therefore, an object of the present invention to provide a motion base that has the platform thereof supported by three elements which act upon a point adjacent one side of that platform and by three further elements which act upon a second point adjacent the opposite side of that platform; and wherein each of those points can be moved Patented Sept. 22, 1970 ice in the X, Y and Z directions, and that platform can rotate about an axis extending between those points, to provide six degrees of motion for that platform.

Other and further objects and advantages of the present invention should become apparent from an examination of the drawing and accompanying description.

In the drawing and accompanying description two preferred embodiments of the present invention are shown and described but it is to be understood that the drawing and accompanying description are for the purpose of illustration only and do not limit the invention and that the invention will be defined by the appended claims.

In the drawing, FIG. 1 is a perspective view of one preferred embodiment of motion base that is made in accordance with the principles and teachings of the present invention,

FIG. 2 is a broken-away, perspective view, on a larger scale, of part of the motion base shown in FIG. 1,

FIG. 3 is an exploded view, on the scale of FIG. 2, .of a portion of the structure shown in FIG. 2,

FIG. 4 is an exploded view of one of the connectors used in the motion base shown in FIG. 1,

FIG. 5 is a side elevational view, on a scale intermediate those of FIGS. 1 and 2, of the motion base shown in FIG. 1, and it shows one position of the components of that motion base by solid lines and two other positions of those components by dotted lines,

FIG. 6 is a broken, front elevational view, on the scale of FIG. 5, of the motion base shown in FIG. 1, and it shows a position of the components of that motion base by solid lines and a further position of those components by dotted lines,

FIG. 7 is a plan view, on the scale of FIG. 5, of the motion base shown in FIG. 1, and it shows an additional position of the components of that motion base by solid lines and shows two still further positions of those components by dotted lines,

FIG. 8 is a perspective view, on a scale intermediate those of FIGS. 2 and 5, of a linkage secured to the underside of the platform of the motion base shown in FIG. 1,

FIG. 9 is a perspective view of another preferred embodiment of motion base that is made in accordance with the principles and teachings of the present invention,

FIG. 10 is a partially broken-away, front elevational view, on a larger scale, through the motion base shown in FIG. 9,

FIG. 11 is a partially broken-away, perspective view of a part of the motion base of FIG. 9, and it is taken on a scale larger than that of FIG. 10,

FIG. 12 is a partially-sectioned view, on a larger scale,

through one of the mechanisms that sense the positions of the pistons relative to the cylinders of the motion bases of FIGS. 18 and 9-11.

FIG. 13 is a sectional view, on the scale of FIG. 12, through the sensing mechanism of FIG. 12, and it is taken along the plane indicated by the line 13-13 in FIG. 12,

FIG. 14 is another sectional view, on the scale of FIG. 12, through the sensing mechanism of FIG. 12, and it is taken along the plane indicated by the line 1414 in FIG. 12,

FIG. 15 is a partially-broken sectional view on the scale of FIG. 12, through the sensing mechanism of FIG. 12, and it is taken along the plane indicated by the line 15-15 in FIG. 13, and

FIG. 16 is an exploded view of the short shaft of FIG. 3 and of a modified form of piston, connector and pin used with that short shaft.

Referring to FIGS. 1-8 in detail, the numeral 20 denotes the platform of one preferred embodiment of a motion base that is made in accordance with the principles and teachings of the present invention; and that platform supports and carries a simulated cockpit 21. That platform can be made to have any desired size and configuration; and, similarly, that simulated cockpit can be made to have any desired size and configuration. Four legs 19 extend downward from the under surface of that platform; and those legs will hold that platform solidly in horizontal position whenever the motion base is at rest. A pivot block 22 is disposed within the simulated cockpit 21; and that pivot block will be mounted so it is rigidly secured to that platform 20. If desired, that pivot block could be fixedly secured to a bracket or framework which was rigidly mounted on the platform and which was wholly external of the simulated cockpit 21.

The numeral 24 denotes a short shaft which has a reduced-diameter inner end 25 and which has a clevis-like outer end 26; and that reduced-diameter inner end extends into and through an opening in the pivot block 22. A retaining ring 27 telescopes over, and is pinned to, that portion of the reduced-diameter inner end 25 which extends through the opening in that pivot block; and that retaining ring will hold the shaft 24 in assembled relation with that pivot block-and thus with the platform 20-while permitting rotation of that shaft relative to that pivot block and to that platform. A piston 28 has a planished end, with a self-aligning bearing 29 therein, that telescopes into the slot of the clevis-like outer end 26 of the shaft 24; and that planished end is sufficiently narrower than that slot to permit that piston to wobble relative to that shaft. A trough-shaped member 30 has openings 34- in the walls thereof, and those openings are aligned with the opening in the elevis-like end 26 of the shaft 24 and with the opening in the self-aligning bearing 29 carried by the planished end of the piston 28; and a pin 36 extends through those aligned openings to hold that shaft, that piston and that trough-shaped member in assembled relation while permitting free and ready rotation of that shaft, of that piston, and of that trough-shaped member relative to each other. That trough-shaped member has a cylindrical lower end 32; and a connector 38 has a sleeve-like portion 40 which is telescoped upwardly over that cylindrical lower end. The engagement between the sleeve-like portion 40 of the connector 38 and the cylindrical lower end 32 of the trough-shaped member 30 is intimate enough to hold the axes of that troughshaped member and of that connector coaxial, but is loose enough to permit ready rotation of that connector relative to that trough-shaped member. A piston 42 has one end thereof rigidly secured to an arcuate segment, at the upper end of the connector 38, which closely abuts the outer surface of the trough-shaped member 30. The numeral 44 denotes a connector which has a sleeve-like portion 46 which is telescoped upwardly over the cylindrical lower end 32 of the trough-shaped member 30. The engagement between the sleeve-like portion 46 of the connector 44 and the cylindrical lower end 32 of the trough-shaped member 30 is intimate enough to hold the axes of that connector and of that trough-shaped member coaxial, but is loose enough to permit ready rotation of that connector relative to that trough shapedmember. A piston 48 has one end thereof rigidly secured to an arcuate segment, at the upper end of the connector 44, which closely abuts the outer surface of the troughshaped member 30. The shank of the connector 44 is longer than the shank of the connector 38; and this is important, because it enables the axes of the pistons 42 and 48 to intersect the axis of the pin 36. The numeral 50 denotes a retaining ring which is threaded onto a thread on the cylindrical lower end 32 of the troughshaped member 30; and a pin 51 extends through aligned openings in that ring and in that cylindrical lower end to prevent accidental separation of that ring from that cylindrical lower end.

The pin 36 can be considered as a point on the platform 20 which is located adjacent one side of, but above the level of, that platform. The shaft 24 and the pivot block 22 hold that pin against movement laterally of that platform; but that pivot block permits that shaft to rotate relative to that platform, and thus permits that pin to rotate relative to that platform. The pin 36 permits the piston 28 to rotate about the axis of that pin, and the self-aligning bearing 29 carried by the planished end of that piston permits that piston to rotate about the axis of the shaft 24; and hence that piston can be rotated about the axis of the pin 36 and about the axis of the shaft 24. The trough-shaped member 30 can rotate relative to the pin 36 and relative to the shaft 24 about the axis of that pin. The connectors 38 and 44 can rotate about the axis of the trough-shaped member 30 and also can rotate with that trough-shaped member as it rotates about the axis of the pin 36. As a result, the pistons 28, 42 and 48 can experience universal movement relative to the platform 20. The axes of the pistons 28, 42 and 48 extend through that portion of the pin 36 which is disposed between the confronting faces of the clevis-like outer end 26 of the shaft 24; and hence those pistons have minimal moment arms, insofar as their rotation relative to the shaft 24 is concerned.

A second short shaft 54 is rotatably supported by a second pivot block, not shown, which is disposed within the simulated cockpit 21. That second pivot block will be mounted so it is rigidly secured to the platform 20; and that second pivot block will hold the shaft 54 so the axis thereof and the axis of the shaft 24 are coaxial. If desired, that second pivot block could be fixedly secured to a bracket or framework that was rigidly mounted on the platform 20 and that was wholly external of the simulated cockpit 21. The shafts 24 and 54 define an axis that preferably extends through the center of mass of the combined platform 20 and simulated cockpit 21.

The shaft 54 is preferably identical to the shaft 24; and the clevis-like outer end of the former shaft receives the plainished end of a piston 58; and that planished end is sufficiently narrower than the slot in that outer end to permit that piston to wobble relative to that shaft. A trough-shaped member 68, that can be identical to the trough-shaped member 30, is rotatably secured to the shift 54 by a pin 66 which rotatably secures a self-aligning bearing, not shown, in the planished end of the piston 58 to that shaft. A connector, which can be identical to the connector 44, has the sleeve-like portion thereof telescoped upwardly over the cylindrical lower end of the trough-shaped member 68; and a piston 60 is rigidly secured to the arcuate segment at the upper end of that former connector.

The pin 66 can be considered as a second point on the platform 20 which is located adjacent the opposite side of, but above the level of, that platform. The shaft 54 holds that pin against movement laterally of that platform, but that shaft can rotate relative to that paltform and thus can permit that pin to rotate relative to that platform. The pin 66 permits the piston 58 to rotate about the axis of that pin, and the self-aligning bearing carried by the planished end of that piston, permits that piston to rotate about the axis of the shaft 54; and hence that piston can be rotated about the axis of the pin 66 and about the axis of the shaft 54. The trough-shaped member 68 can rotate relative to the pin 66 and relative to the shaft 54 about the axis of that pin. The connector which is associated with that trough-like member 68 can rotate about the axis of that trough-like member and also can rotate with that trough-shaped member as that trough-shaped member rotates about the axis of the pin 66. As a result, the pistons 58 and 60 can experience universal movement relative to the platform 20. The axes of the pistons 58 and '60 extend through that portion of the pin 66 which is disposed between the confronting faces of the clevis-like outer end of the shaft 54; and hence those pistons have minimal moment arms, insofar as their rotation relative to the shaft 54 is concerned.

The pistons 28, 42 and 48 constitute portions of three elements which act upon the pin 36; and the pistons 58 and 60 constitute portions of two elements, and the platform constitutes a third element, which act upon the pin 66. As a result, the pin 36 represents a point which is acted upon by three elements; and the pin 66 represents a second point which is acted upon by three further elements. Those two points are the points at which the forces, which support and which move the platform 20 in the X, Y and Z directions, are applied to that platform. Those two points define an axis which is transverse of the elongated axis of the platform 20; and that platform can rotate about that transverse axis.

The numeral 74 generally denotes a tripod; and the numeral 76 generally denotes one of the legs of that tripod. That leg includes an elongated rod 78, an elongated rod 80, and an elongated rod 82; and a spacer 84 engages and is fixedly secured to each of those rods, approximately midway between the upper and lower ends of those rods, to space the midpoints of those rods apart. The lower ends of the rods 78, 80 and 82 are secured together and to a foot 83; and the upper ends of those rods are secured together and to a cap for the tripod 74. The other legs of that tripod are denoted by the numerals 86 and 88; and those legs preferably are identical to the leg 76. The lower ends of those legs are equipped, respectively, with feet 87 and 89; and the upper ends of those legs are secured to the cap 90. The feet 83, 87 and 89, respectively, of the legs 76, 86 and 88 of the tripod 74 can be solidly secured to the floor or to some low-lying support in a building or other structure. In the preferred embodiment of motion base shown by FIGS. 1-8, the feet 83, 87 and 89 are secured to the floor of a building.

The numeral 92 denotes a clevis-like support that is pivoted to the cap 90 of the tripod 74, and that depends downwardly from the under-surface of that cap. A cylinder 94 has a planished end with an opening therein, and that planished end extends into the recess defined by the clevis-like support 92. A pin 96 telescopes through the openings in the walls of the clevis-like support 92 and through the opening in the planished end of the cylinder 92 to hold that cylinder in assembled relation with that clevis-like support while permitting rotation of that cylinder relative to that clevis-like support. That cylinder telescopes over the upper end of the piston 58; and it confines and supports that piston. The cylinder 94 and the piston 58 constitute a double-acting hydraulic actuator of standard and usual form. That actuator pivots about the pin 96, and the clevis-like support 92 pivots about a vertical axis relative to the cap 90; and hence that actuator can experience universal movement.

The numeral 98 denotes a ball-equipped plate which can be secured to the floor or low-lying support of the building or other structure in which the motion base is located. A two-piece clamp 103 has a roughly semicylindrical section 99 with a hollow lower end, and also has a roughly semi-cylindrical section 100 with a hollow lower end; and the hollow lower ends of those roughly semi-cylindrical sections define a socket which accommodates the ball on the ball-equipped plate 98. Bolts 101 and nuts 104 hold the roughly semi-cylindrical sections 99 and 100 of the clamp 93 in assembled relation with each other and with the lower end of a cylinder 102. That cylinder telescopes over the lower end of the piston 60; and it confines and supports that piston. The cylinder 102 and the piston 60 constitute a double-acting hydraulic actuator of standard and usual form. That actuator can experience universal movement relative to the ballequipped plate 98.

The numeral generally denotes a tripod which can be identical to the tripod 74. The former tripod has a leg 122 with a foot 124, a leg 126 with a foot 128, a leg 130 with a foot 132, and a cap 134 with a clevis-like support 136 pivoted thereto. In the preferred embodiment of motion base shown by FIGS. 1-8, feet 124, 128 and 132, respectively, of the legs 122, 126 and 130 are secured to the floor of the building in which the motion base is 10- cated. A cylinder has a planished end with an opening therein, and a pin 138 extends through openings in the cevis-like support 136 and through the opening in the planished end of the cylinder 140 to hold that cylinder in assembled relation with that clevis-like support. That cylinder telescopes over the upper end of the piston 28; and it confines and supports that piston. The cylinder 140 and the piston 28 constitute a double-acting hydraulic actuator of standard and usual form. That actuator pivots about the pin 138, and the clevis-like support 136 pivots about a vertical axis relative to the cap 134; and hence that actuator can experience universal movement.

The numeral 142 denotes a ball-equipped plat which can be identical to the ball-equipped plate 98; and the numeral 144 denotes a two-piece clamp which can be identical to the two-piece clamp 103. The former twopiece clamp rotatably secures the lower end of a cylinder 146 to the ball-equipped plate 142. That cylinder telescopes over the lower end of the' piston 42; and it confines and supports that piston. The cylinder 146 and the piston 42 constitute a double-acting hydraulic actuator of standard and usual form; and that actuator can experience universal movement relative to the ball-equipped plate 142.

The numeral 148 denotes a ball-equipped plate which can be identical to the ball-equipped plate 98; and the numeral 150 denotes a two-piece clamp which can be identical to the two-piece clamp 103. The former twopiece clamp rotatably secures the lower end of a cylinder 152 to the ball-equipped plate 148. That cylinder telescopes over the lower end of the piston 48; and it confines and supports that piston. The cylinder 152 and the piston 48 constitute a double-acting hydraulic actuator of standard and usual form; and that actuator can experience universal movement relative to the ball-equipped plate 148. The ball-equipped plates 142 and 148 can be secured to the floor of the building in which the motion base is located.

The numeral 154 denotes a hinge plate that is secured to the under-surface of the platform 20; and an elongated, generally-triangular hinge plate 156 is rotatably secured to the hinge plate 154 by a hinge pin 158. The elongated, generally-triangular hinge plate 156 has a slot 160 therein, and that slot extends to the free end of that elongated, generally-triangular hinge plate. A hinge block 162 has upstanding ears at the opposite sides thereof; and an elongated rod 164 is secured to that hinge block by a universal joint, not shown, which can be of standard and usual design and construction. A two-piece clamp 166, which can be identical to the two-piece clamp 103, rotatably secures the lower end' of the rod 164 to a ballequipped plate 168; and that plate can be secured to the floor of the building in which the motion base is located. A piston 170 has a planished end with an opening therein; and that planished end extends through the slot 160 in the elongated, generally-triangular hinge plate 156- to the hinge block 162. A hinge pin 172 extends through aligned openings in the ears on the hinge block 162, through openings in the free end of the elogated, generally-triangular hinge plate 156, and through the opening in the planished end of the piston 170. A cylinder 174 telescopes over the free end of the piston 170, and that cylinder will confine and support that free end; and that cylinder and that piston constitute a double-acting hydraulic actuator of standard and usual form. A bracket 176 is secured to the under-surface 0f the platform 20 to the left of the hinge plate 154, as that hinge plate is viewed in FIG. 7. A pin 178 rotatably secures the lefthand end of the cylinder 174 to the bracket 176.

Whenever the motion base of FIGS. 1-8 is at rest, the legs 19 will rest upon the floor of the building in which that motion base is located; and those legs will hold the platform 20 solidly in horizontal position. At such time, the simulated cockpit 21 will be in the position shown by FIG. 1 and by the lower dotted lines in FIG. 5.

To enable that simulated cockpit to assume an attitude, such as the inclined position shown by the upper dotted lines in FIG. 5, which at least partially simulates the attitude which the cockpit of the corresponding aircraft would assume during takeoff or climbing, a computer, not shown, will determine the positions which the pistons 28, 42, 48, 58, 60 and 170 should assume, respectively, relative to the cylinders 140, 146, 152, 94, 102 and 174; and that computer will then cause appropriate volumes of hydraulic fluid to be supplied to the appropriate ports of those cylinders. The pistons 28 and 58 will move inwardly of the cylinders 140 and 94, respectively, to apply upwardly-directed forces to the shafts 24 and 54, and thus to the platform 20'. The pistons 42, 48 and 60 will move outwardly of the cylinders 146, 152 and 102, respectively, to permit the platform 20 to move upwardly. The piston 170 will move outwardly of the cylinder 174 to cause the platform 20 to rotate about the axis defined by the shafts 24 and 54, and thus to assume the inclined position shown by the upper dotted lines in FIG. 5. The computer can hold the platform 20 in that inclined position as long as desired, by blocking all movement of hydraulic fluid relative to the cylinders 94, 102, 140, 146, 152 and 174. Thereafter, that computer can cause that platform to pitch toward a steeper climbing attitude, to pitch toward a shallower climbing attitude, to pitch to a horizontal position, to roll to the left or right, to heave upwardly or downwardly, to slip to the left or right, to yaw to the left or right, or to move forwardly or rearwardly. Furthermore, that computer can cause that platform to accomplish several of those motions simultaneously. Many different kinds of computing devices, including general purpose analog computers, general purpose digital computers, hybrid analogdigital computers, special purpose analog computers, special purpose digital computers, special mechanical control devices, could be used to program and effect the various motions and positions desired for the platform 20.

For purposes of illustration, it will be assumed that the platform 20 is to be rotated from the inclined position shown by the upper dotted lines to the horizontal position shown by solid lines in FIG. and, to effect such rotation, the computer will continue to block all movement of hydraulic fluid relative to the cylinders 94, 102, 140, 146 and 152, but will supply hydraulic fluid to the cylinder 174. Thereupon, the piston 170 will move inwardly of that cylinder, to rotate the platform about the axis defined by the shafts 24 and 54, until that platform assumes the position shown by solid lines in FIG. 5. At such time the simulated cockpit 21 will be simulating straight and level flight.

In moving the platform 20 from the lower dotted-line position to the upper dotted-line position in FIG. 5, the motion base of FIGS. 1-8 simulated a combination of heave and pitch motions. In rotating the platform 20 from the upper dotted-line to the solid-line position in FIG. 5, the motion base simulated a pitch motion. If the platform 20 were to be moved directly from the solid-line position to the lower dotted-line position of FIG. 5, or vice versa, the motion base would simulate heave motion.

In all positions of the platform 20, other than the lower dotted-line position shown in FIG. 5, the cylinders 94, 102, 140, 146 and 152 and the pistons 58, 60, 28, 42 and 48 will be applying forces to the platform 20. The forces which the cylinders 94 and 140 and the pistons 58 and 28 apply to the platform 20 will be tensile forces; and those tensile forces will be the forces that are primarily relied upon to raise the platform 20. By having the primary raising forces applied to the platform 20 by the actuators which include the cylinders 94 and 140 and pistons 58 and 28, the motion base of FIGS. 1-8 minimizes the columnar forces which must be developed by the actuators which include the cylinders 102, 146 and 152 and the pistons 60, 42 and 48. Because the columnar forces which must be developed by those actuators are minimized, those actuators can be made lighter in weight than the standard and usual actuators, where the various actuators are used with platforms and simulated cockpits of the same size and weight. Further, because the columnar forces which must be developed by those actuators are minimized, the use of standard and usual actuators to provide those columnar forces and the use of strong actuators to provide the required tensile forces enables higher than normal hydraulic pressures to be used. In either event the actuators, which include the cylinders 102, 146 and 152 and the pistons 60, 42 and 48, can be made more rapid in action than can the actuators of most prior motion bases.

To enable the platform 20 of the motion base shown by FIGS. l-8 to simulate forward motion, the computer will cause the pistons 60 and 48 to move inwardly of the cylinders 102 and 152, respectively, will cause the pistons 58 and 28 to move outwardly of the cylinders 94 and 140, respectively, will cause the piston 42 to move outwardly of the cylinder 46, and will cause the piston to move inwardly of the cylinder 174. The resulting movements of those pistons relative to those cylinders will cause the platform 20 to move from the solid-line position to the right-hand most dotted line position in FIG. 7. The self-aligning bearings carried by the planished lower ends of the pistons 28 and 58 will permit those pistons to rotate relative to the axes of the shafts 24 and 54 as that platform so moves. To enable the platform 20 to simulate rearward motion, the computer will cause the pistons 60 and 48 to move outwardly of the cylinders 102 and 152, respectively, will cause the pistons 58 and 28 to move outwardly of the cylinders 94 and 104, respectively,

will cause the piston 42 to move inwardly of the cylinder 146, and will cause the piston 170 to move outwardly of the cylinder 174. Again, the self-aligning bearings carried by the planished lower ends of the pistons 28 and 58 will permit those pistons to rotate relative to the axes of the shafts 24 and 54 as that platform so moves.

To enable the platform 20 of the motion base shown in FIGS. 1-8 to simulate yaw, wherein the leading edge of the simulated cockpit 21 is disposed to the right of the simulated direction of flight of that cockpit and wherein the trailing edge of that simulated cockpit is disposed to the left of that simulated direction of flight, the computer will cause the pistons 28, '42, 58 and 60 to move outwardly of the cylinders 140, 146, 94 and 102, and will cause the piston 48 to move inwardly of the cylinder 152. The computer will leave the position of the piston 170 relative to that of the cylinder 174 substantially unchanged; but the hinge plate 156 and the bracket 176 will move [relative to the ball-equipped plate 168the universal joint between the rod 164 and the hinge block 162 permitting such movement.

To enable the platform 20 of the motion base shown in FIGS. l8 to simulate yaw, wherein the leading edge of the simulated cockpit 21 is disposed to the left of the simulated direction of flight of that cockpit and wherein the trailing edge of that simulated cockpit is disposed to the right of that simulated direction of flight, the computer will cause the pistons 28, 48 and 58 to move outwardly of the cylinders 140, 152 and 94, respectively, and will cause the pistons 42 and 60 to move inwardly of the cylinders 1 46 and 102, respectively. The computer will again leave the position of the piston 170 relative to that of the cylinder 174 substantially unchanged; but the hinge plate 156 and the bracket 176 will again move relative to the ball-equipped plate 168the universal joint between the rod 164 and the hinge block 162 permitting such movement.

If the motion base of FIGS. 1-8 was modified to displace the ball-equipped plate 168 from its position in vertical registry with the hinge plate 154, the piston 170 would tend to move relative to the cylinder 174 as the platform 20 was moved to simulate yaw. In such event,

the computer would determine and efiect the required direction and amount of movement of that piston relative to that cylinder.

To enable the platform 20 of the motion base shown in FIGS. 1-8 to simulate roll, wherein the plane of that platform inclines upwardly from lower left to upper right as shown by FIG. 6, the computer will cause the pistons 28 and 60 to move inwardly of the cylinders 140 and 102, respectively, and will cause the pistons 42, 48 and 58 to move outwardly of the cylinders 146, 152 and 94, respectively. The computer will also change the position of the piston 170 relative to that of the cylinder 174; and the hinge plate 156 and the bracket 176 will move relative to the ball-equipped plate 168the universal joint between the rod 164 and the hinge block 162 permitting such movement. To enable the platform 20 of the motion base shown in FIGS. 1-8 to simulate roll, wherein the plane of that platform inclines upwardly from lower right to upper left in FIG. 6, the computer will cause the pistons 42, 48 and 58 to move inwardly of the cylinders 146, 152 and 94, respectively, and will cause the pistons 28 and 60 to move outwardly of the cylinders 140 and 102. The computer will also change the position of the piston 170 relative to that of the cylinder 174; and the hinge plate 156 and the bracket 176 will move relative to the ball-equipped plate 168.

To enable the platform 20 of the motion base shown in FIGS. 18 to simulate slip motion wherein that platform moves to the right, as shown by FIG. 6, the computer will cause the pistons 28, 42 and 48 to move inwardly of the cylinders 140, 146 and 152, respectively, and will cause the pistons 58 and 60 to move outwardly of the cylinders 94 and 102, respectively. The computer will also change the position of the piston 170 relative to that of the cylinder 174; and the hinge plate 156 and the bracket 176 will move relative to the ball-equipped plate 168the universal joint between the rod 164 and the hinge block 162 permitting such movement. To enable the platform 20 of the motion base shown in FIGS. 1-8 to simulate slip motion wherein that platform moves to the left, as that platform is shown in FIG. 6, the computer will cause the pistons 58 and 60 to move inwardly of the cylinders 94 and 102, respectively, and will cause the pistons 28, 42 and 48 to move outwardly of the cylinders 140, 146 and 152, respectively. The computer will also change the position of the piston 170 relative to that of the cylinder 174; and the hinge plate 156 and the bracket 176 will move relative to the ball-equipped plate 168.

It thus can be seen that the motion base of FIGS. l8 can cause the platform 20 thereof to experience forward motion, slip, roll, pitch, heave and yaw. As a result, that motion base enables that platform to provide six degrees of motion for the simulated cockpit 21. Those six degrees of motion can be provided separately; or any desired combination of those six degrees of motion can be provided simultaneously. Prior to, during, and after the conclusion of any of the various motions of the platform 20, the pin 36 and the shaft 24 will be supported by the pistons 28, 42 and 48; and those pistons, and the cylinders which confine and support them, will solidly hold and support that pin and shaft. Prior to, during, and after the conclusion of any of the various motions of the platform 20, the pin 66 and the shaft 54 will be supported by the pistons 58 and 60 and the platform 20; and that platform and those pistons, and the cylinders which confine and support them, will solidly hold and support that pin and shaft. Thus, each of the two points which are represented by the pins 36 and 66 will be directly supported by three elements; and those three element forces will hold that point in any desired position in space relative to the floor of the building or other structure in which the motion base is located.

Referring particularly to FIGS. 91 1, the numeral 190 denotes the platform of a second preferred embodiment of motion base that is made in accordance with the principles and teachings of the present invention; and a simulated cockpit 192 is mounted on and movable with that platform. That platform can be made to have any desired size and configuration; and, similarly, that simulated cockpit can be made to have any desired size and configuration. A bracket 194 is mounted within the simulated cockpit 192, and is rigidly mounted relative to the platform and that bracket supports a hydraulic or other motor 196. A short shaft 198, which is generally similar to the short shaft 54 of the motion base of FIGS. 1-8, is rotatably supported by the motor 196; and that shaft is thus secured to the platform 190 above the level of that platform. That shaft has a clevis-like outer end 200; and a connector 202, with eyes at either end thereof, has one of the eyes thereof disposed within the space defined by the clevis-like end 200. A pin 205 extends through that one eye and through aligned openings in that clevis-like end; and a trough-shaped member 204, which can be identical to the trough-shaped member 30 of the motion base of FIGS. 1-8, is rotatably secured to the shaft 198 and to the connector 202 by that pin. A connector 208, which can be identical to the connector 38 in the motion base of FIGS. 1-8, has a sleeve-like portion that telescopes upwardly over the cylinder-like lower end of the trough-shaped member 204; and a connector 206, which can be identical to the connector 44 in the motion base of FIGS. 1-8, has a sleeve-like portion that telescopes upwardly over that cylinder-like lower end. A retaining ring 209 is threaded onto a thread on the cylinder-like lower end of the trough-shaped member 204, and a pin will pass through aligned openings in that retaining ring and in that lower end to prevent accidental separation of that retaining ring from that trough-shaped member.

A piston 210 is rigidly secured to the connector 206; and the lower end of that piston extends into a hydraulic cylinder 212. The lower end of that cylinder is rotatably secured to a ball-equipped plate 216 by a two-piece clamp 214 which can be identical to the two-piece clamp 103 of the motion base of FIGS. 1-8. The numeral 218 denotes a piston which is rigidly secured to the connector 208; and that piston extends into a hydraulic cylinder 220. The lower end of that cylinder is rotatably secured to a ball-equipped plate 224 by a two-piece clamp 222 which can be identical to the two-piece clamp 103 of the motion base of FIGS. 1-8. The cylinder 212 and the piston 210 constitute a double-acting hydraulic actuator of standard and usual form; and, similarly, the cylinder 220 and the piston 218 constitute a double-acting hydraulic actuator of standard and usual form. The clamps 214 and 222 coact with the ball-equipped plates 216 and 224 to permit universal movement of the cylinders 212 and 220 relative to those plates. Those plates can be secured to the floor or to some low-lying support in the building or structure in which the motion base of FIGS. 9-11 is located.

The numeral 226 generally denotes a tripod which can be similar to, but shorter than, the tripod 74 of the motion base in FIGS. 18. The former tripod has a cap 228; and a pulley 230 is rotatably supported by that cap. A motor 232 is suitably secured to the floor or low-lying support in the building or structure in which the motion base of FIGS. 9-11 is mounted; and that motor can drive a winch 234. A flexible cable 236 has one end thereof passing through and secured to the upper eye of the connector 202, and has the other end thereof secured to and wound around the drum of the winch 234.

The numeral 240 denotes a short shaft which extends outwardly from the right-hand side of the simulated cockpit 192, as that simulated cockpit is viewed in FIG. 10. That short shaft is rotatably secured to the platform 190 by a hydraulic motor 247 which is rigidly secured to that platform; and that short shaft is disposed above the level of that platform. That short shaft will be coaxial with the short shaft 198; and the axis defined by those short shafts will preferably extend through the center of mass of the combined platform 190 and simulated cockpit 192. The outer end of the shaft 240 is clevis-like in configuration; and a pin 239 secures the lower eye of a connector, which is similar to the connector 202, to that outer end. A flexible cable 241 has one end thereof connected to the upper eye of the former connector. The shaft 240 has a trough-shaped member 245, which is similar to the trough-shaped member 204, rotatably secured to it by the pin 239. A piston 242 is secured to the trough-shaped member 245 by a connector which can be identical to the connector 206; and a piston 243 is secured to that trough-shaped member by a connector which can be identical to the connector 208. The lower end of the piston 242 is confined and supported by a cylinder 244, and the lower end of the piston 243 is confined and supported by a cylinder 250. The cylinder 244 and the piston 242 constitute a double-acting hydraulic actuator of standard and usual form; and similarly, the cylinder 250 and the piston 243 constitute a doubleacting hydraulic actuator of standard and usual form. A two-piece clamp 246, which can be identical to the twopiece clamp 103, rotatably secures the lower end of the cylinder 244 to a ball-equipped plate 248. A twopiece clamp 252, which can be identical to the two-piece clamp 103, rotatably secures the lower end of the cylinder 250 to a ball-equipped plate 254. The clamps 246 and 252 coact with the ball-equipped plates 248 and 254 to permit universal movement of the cylinders 244 and 250 relative to those plates. Those plates can be secured to the floor or to some low-lying support in the building or structure in which the motion base of FIGS. 9-11 is located.

The numeral 256 denotes a tripod which can be identical to the tripod 226; and the former tripod has a cap 257 that rotatably supports a pulley which supports the cable 241. One end of that cable is secured to the short shaft 240 by the pin 239; and the other end of that cable is secured to a winch 260 which is driven by a motor 258.

The numeral 264 denotes a pit in the floor of the building in which the motion base of FIGS. 9-11 is located; and abutments 266 and 268 extend inwardly from opposite sides of that pit to underlie portions of the sides of the platform 1.90. Those abutments are in register with each other and in vertical registry with the shafts 198 and 240; and they provide an H-shaped configuration for the pit 264. Those abutments support the platform 190 and the simulated cockpit 192 whenever the motion base of FIGS. 9ll is at rest.

The pin 205 can be considered as a point on the platform 190 which is located adjacent one side of, but above the level of, that platform. The shaft 198 and the hydraulic motor 196 hold that pin against movement laterally of that platform; but that hydraulic motor permits that shaft to rotate relative to that platform, and thus permits that pin to rotate relative to that platform. The pin 205 permits the cable 236 to rotate about the axis of that pin, and the flexible nature of that cable permits that cable to be rotated about the axis of the shaft 198. The trough-shaped member 204 can rotate relative to the pin 205 and relative to the shaft 198 about the axis of that pin. The connectors 206 and 208 can rotate about the axis of the trough-shaped member 204 and also can rotate with that trough-shaped member as it rotates about the axis of the pin 205. As a result, the cable 236 and the pistons 210 and 218 can experience universal movement relative to the platform 190. The axes of that cable and of those pistons extend through that portion of the pin 205 which is disposed between the confronting faces of the clevis-like outer end 200 of the shaft 198; and hence that cable and those pistons have minimal moment arms, insofar as their rotation relative to the shaft 198 is concerned.

The pin 239 can be considered as a second point on the platform 190 which is located adjacent the opposite side of, but above the level of, that platform. The shaft 240 holds that pin against movement laterally of that platform, but that shaft can rotate relative to that platform and thus can permit that pin to rotate relative to that platform. The pin 239 permits the cable 241 to rotate about the axis of that pin, and the flexible nature of that cable permits that cable to be rotated about the axis of the shaft 240. The trough-shaped member 245 can rotate relative to the pin 239 and relative to the shaft 240 about the axis of that pin. The connectors which are associated with the trough-like member 245 can rotate about the axis of that trough-shaped member and also can rotate with that trough-shaped member as that troughshaped member rotates about the axis of the pin 239. As a result, the pistons 242 and 243 can experience universal movement relative to the platform 190*. The axes of the cable 241 and of the pistons 242 and 243 extend through that portion of the pin 239 which is disposed between the confronting faces of the clevis-like outer end of the shaft 240; and hence that cable and those pistons have minimal moment arms, insofar as their rotation relative to the shaft 240 is concerned.

The cable 236 constitutes an element and the pistons 210 and 218 constitute portions of two elements which act upon the pin 205; and the cable 241 constitutes a further element and the pistons 242 and 243 constitute portions of two further elements which act upon the pin 239. As a result, the pin 205 represents a point which is acted upon by three elements; and the pin 239 represents a second point which is acted upon by three further elements. Those two points are the points at which the forces, which support and move the platform 190 in the X, Y and Z directions, are applied to that platform. Those two points define an axis which is transverse of the elongated axis of the platform 190; and that platform can rotate about that transverse axis.

The motion base shown in FIGS. 9-11 differs from the motion base shown in FIGS. 1-8, in that the cable 236, the motor 232 and the winch 234 have been substituted for the actuator which includes the cylinder 94 and the piston 58, in that the cable 241, the motor 258 and the winch 260 have been substituted for the actuator which includes the cylinder and the piston 28, in that an additional actuator which includes the piston 210 and the cylinder 212 has been added, in that the legs 19 have been removed, and in that the pit 264 has been provided. The cables 236 and 241 will provide the tensile forces in FIGS. 9l1 which are provided by the actuators in FIGS. 1-8 that are constituted by the cylinders 94 and 130 and by the pistons 58 and 28. Any downwardly-acting forces that are supplied by those two actuators in FIGS. 1-8 will be provided in FIGS. 911 by the combined weights of the platform and the simulated cockpit 192. Also, any inwardly-acting forces that are provided by those two actuators in FIGS. 18, will be provided in FIGS. 9-11 by the actuators constituted by the cylinders 212, 220, 244 and 250 and the pistons 210, 218, 242 and 243. As a result, the platform 190 and the simulated cockpit 192 in FIGS. 9l1 can be given all of the six degrees of motion which can be given to the platform 20 and the simulated cockpit 21 in FIGS. 1-8.

The motors 196 and 247 in the motion base of FIGS. 911 will perform the functions that are provided in the motion base of FIGS. 1-8 by the hinge plates 154 and 156, the hinge block 162 and rod 164, the bracket 176, and the cylinder 174 and piston 170. As a result, the platform 190 and the simulated cockpit 192 can be rotated in either direction about the transverse axis defined by the shafts 198 and 240. The pit 264 can accommodate the forward end of the platform 190 and the forward end of the simulated cockpit 192 as that platform and simulated cockpit are rotated in the clockwise direction in FIG. 9 to simulate a descending attitude of the corresponding aircraft. That pit also can accommodate the rear end of that platform and the rear end of that simulated cockpit as that platform and simulated cockpit are rotated in the counter clockwise direction in FIG. 9 to simulate a climbing attitude of that aircraft. By permitting the forward ends and the rear ends of that platform 190 and of the simulated cockpit 192 to extend down below the floor level, the pit 264 reduces the overall height needed for the building or structure in which the motion base of FIGS. 9-11 is located.

In all positions of the platform 190, other than its position of rest wherein it is supported by the abutments 266 and 268, the cables 236 and 241, the cylinders 212, 220, 244 and 250, and the pistons 210, 218, 242 and 243 will be applying forces to that platform. The forces which the cables 236 and 241 apply to that platform will be tensile forces; and those tensile forces will be the forces that are primarily relied upon to raise that platform. By having the primary raising forces applied to the platform 190 by the cables 236 and 241, the motion base of FIGS. 9-11 minimizes the columnar forces which must be developed by the actuators which include the cylinders 212, 220, 244 and 250 and the pistons 210, 218, 242 and 243. Because the columnar forces which must be developed by those actuators are minimized, those actuators can be made lighter in weight than the standard and usual actuators, where the various actuators are used with platforms and simulated cockpits of the same size and weight. Further, because the columnar forces which must be developed by those actuators are minimized, the use of standard and usual actuators to provide those columnar forces and the use of strong cables to provide the required tensile forces enables higher than normal pressures to be used. In either event the actuators, which include the cylinders 212, 220, 244 and 250 and the pistons 210, 218, 242 and 243, can be made more rapid in action than can the actuators of most prior motion bases.

To enable the platform 190 of the motion base shown by FIGS. 9-11 to simulate forward motion, the computer will cause the pistons 218 and 242 to move inwardly of the cylinders 220 and 244, respectively, will cause the winches 234 and 260 to pay out the cables 236 and 241, respectively, and will cause the pistons 210 and 243 to move outwardly of the cylinders 212 and 250, respectively. The resulting movement of those cables and pistons will cause the platform 190 to move forwardly in FIG. 9. To enable that platform to simulate rearward motion, the computer will cause the pistons 218 and 242 to move outwardly of the cylinders 220 and 244, respectively, will cause the winches 234 and 260 to pay out the cables 236 and 241, respectively, and will cause the pistons 210 and 243 to move inwardly of the cylinders 212 and 250.

To enable the platform 190 of the motion base shown in FIGS. 9-11 to simulate yaw, wherein the leading edge of the simulated cockpit 192 is disposed to the right of the simulated direction of flight of that cockpit and wherein the trailing edge of that simulated cockpit is disposed to the left of that simulated direction of flight, the computer will cause the pistons 218 and 243 to move outwardly of the cylinders 220 and 250, respectively, will cause the pistons 210 and 242 to move inwardly of the cylinders 212 and 244, respectively, and will cause the winches 234 and 260 to pay out the cables 236 and 241, respectively. To enable the platform 190 of the motion base shown in FIGS. 9-11 to simulate yaw, wherein the leading edge of the simulated cockpit 192 is disposed to the left of the simulated direction of flight of that cockpit and wherein the trailing edge of that simulated cockpit is disposed to the right of that simulated direction of flight, the computer will cause the pistons 210 and 242 to move outwardly of the cylinders 212 and 244, respectively, will cause the pistons 218 and 243 to move inwardly of the cylinders 220 and 250, respectively, and will cause the winches 234 and 260 to pay out the cables 236 and 241, respectively.

To enable the platform of the motion base shown in FIGS. 9-11 to simulate roll, wherein the plane of that platform inclines upwardly from lower left to upper right in FIG. 10, the computer will cause the pistons 210 and 218 to move inwardly of the cylinders 212 and 220, respectively, will cause the pistons 242 and 243 to move outwardly of the cylinders 244 and 250 respectively, will cause the winch 260 to pull in the cable 241, and will cause the winch 234 to pay out the cable 236. To enable the platform 190 of the motion base shown in FIGS. 9-11 to simulate roll, wherein the plane of that platform inclines upwardly from lower right to upper left in 'FIG. 10, the computer will cause the pistons 210 and 218 to move outwardly of the cylinders 212 and 220, respectively, will cause the pistons 242 and 243 to move inwardly of the cylinders 244 and 250,. respectively, will cause the winch 260 to pay out the cable 241, and will cause the winch 234 to pull in the cable 236.

To enable the platform 190 of the motion base shown in FIGS. 9-11 to simulate slip motion wherein that platform moves to the right in FIG. 10; the computer will cause the pistons 210 and 218 to move outwardly of the cylinders 212 and 220, respectively, will cause the pistons 242 and 243 to move inwardly of the cylinders 244 and 250, respectively, will cause the winch 34 to pay out the cable 236, and will cause the winch 260 to pull in the cable 241. To enable the platform 190 of the motion base shown in FIGS. 9-11 to simulate slip motion wherein that platform moves to the left in FIG. 10, the computer will cause the pistons 210 and 218 to move inwardly of the cylinders 212 and 220, respectively, will cause the pistons 242 and 243 to move outwardly of the cylinders 244 and 250, respectively, will cause the winch 234 to pull in the cable 236, and will cause the winch 260 to pay out the cable 241.

To enable the platform 190 of the motion base shown in FIGS. 9-11 to simulate pitch motion, the computer will cause the various pistons, cylinders, and winches to remain stationary and will cause the hydraulic motors 196 and 247 to rotate the platform 190 about the axis defined by the shafts 198 and 240. Those hydraulic motors can cause the forward end of the platform 190 and the forward end of the simulated cockpit 192 to move upwardly or downwardly, as desired, and can cause those forward ends to move as far in either direction as desired.

To enable the platform 190 of the motion base shown in FIGS. 9-11 to simulate upwardly-directed heave motion, the computer will cause the pistons 210, 218, 242 and 243 to move outwardly of the cylinders 212, 220, 244 and 250, respectively, and will cause the winches 234 and 260 to pull in the cables 236 and 241, respectively. To enable the platform 190 of the motion base shown in FIGS. 9-11 to simulate downwardly-directed heave motion, the computer will cause the pistons 210, 218, 242 and 243 to move inwardly of the cylinders 212, 220, 244 and 250, respectively, and will cause the winches 2341 and 260 to pay out the cables 236 and 241, respective y.

It thus can be seen that the motion base of FIGS. 9-11 can cause the platform 190 thereof to experience forward motion, slip, roll, pitch, heave and yaw. As a result, that motion base enables that platform to provide six degrees of motion for the simulated cockpit 192. Those six degrees of motion can be provided separately; or any desired combination of those six degrees of motion can be provided simultaneously. Prior to, during, and after the conclusion of any of the various motions of the platform 190, the pin 205 and the shaft 198 will be supported by the cable 236 and the pistons 210 and 218. Prior to, during, and after the conclusion of any of the various motions of the platform 190, the pin 239 and the shaft 240 will be supported by the cable 241 and the pistons 242 and 243. Thus, each of the points which are represented by the pins 205 and 239 will be directly supported by three elements; and those three elements will hold that point in any desired position in space relative to the floor of the building or other structure in which the motion base is located.

The tripods 74 and 120 of the motion base of FIGS. 1-8 are useful structures to support the upper ends of the cylinders 94 and 140; and, similarly, the tripods 2'26 and 256 of the motion base of FIGS. 9-11 are useful structures to support the cables 236 and 241. However, none of those tripods is essential; because the upper ends of the cylinders 94 and 140 of the motion base of FIGS. 1-8 could be rotatably secured to structural members in the roof or walls of a building or other structure, and because the cables 236 and 241 could be supported by pulleys that were secured to the roof or walls of a building or other structure. Further, the upper ends of the cylinders 94 and 140, or the pulleys which support the cables 236 and 241, could be held by an inverted U- shaped supporting structure. In fact, any suitable structure could be used to support the upper ends of the cylinders 94 and 140 and to support the pulleys which hold the cables 236 and 241.

The ball-equipped plates 98, 142 and 148 of the motion base of FIGS. 1-8 are shown as being set at the same level. Similarly, the ball-equipped plates 216, 224, 248 and 254 of the motion base of FIGS. 9-11 are shown as being set at the same level. However, each of those ballequipped plates could be set at an individually-different level. Also, each of those ball-equipped plates could be secured to an individually-difierent support. Furthermore, those various ball-equipped plates could be set at individually-diiferent distances from the longitudinal axis of the platform or from the longitudinal axis of the platform 190. Moreover, the caps 90 and 134 of the tripods 74 and 120 of the motion base of FIGS. 1-8, and the caps 228 and 257 of the tripods 226 and 256 of the motion base of FIGS. 9-11, can be set at individually-diiferent levels and at individually-different distances from the longitudinal axis of the platform 20 or from the longitudinal axis of the platform 190.

The fact that the various ball-equipped plates 98, 142, 148, 216, 224, 248 and 254 do not have to be set at the same levels or at the same distances from the longitudinal axis of the platform of either of the motion bases shown by the drawing, and the fact that the various caps 90, 134, 228 and 257 do not have to be set at the same levels or at the same distances from the longitudinal axis of the platform of either of the motion bases shown by the drawing, enable either of the motion bases shown by the drawing to be located in buildings and structures of almost any configuration. The pit 264 of the motion base of FIGS. 9-11, of course, enables that motion base to be located in a relatively low-height building or structure.

The legs 19 on the platform 20 of the motion base of FIGS. 1-8 not only hold that platform and the simulated cockpit 21 solidly in a horizontal position whenever that motion base is at rest, but they will enable that motion base to fail safe in the event the source of hydraulic fluid or any of the actuators of that motion base fails. Specifically, those legs will hold the platform 20 above the level of the floor; and thus will keep that platform from settling down upon, and bending or breaking, the elongated hinge plate 156 or the rod 164, the piston 170 or the cylinder 174, or the. bracket 176. Similarly, the abutments 266 and 268 of the motion base of FIGS. 9-11 not only hold the platform 190 and the simulated cockpit 192 solidly in a horizontal position whenever that motion base is at rest, but they will enable that motion base to fail safe in the event the source of hydraulic fluid for any of the actuators of that motion base fails.

The motion base shown by FIGS. 1-8 has only one actuator, namely the actuator constituted by the cylinder 102 and the piston 61 extending upwardly from the floor to the pin 66 carried by the clevis-like outer end of the shaft 54; and that fact is important, because it avoids the undue stresses and possible breakage which could occur if redundant support was provided for the pins 36 and 66. Specifically, if the piston 69 was, somehow, caused to extend materially outwardly beyond the intended outer limit of its path of movement, the platform 20 and the other actuators therefor would not be distorted or broken; because that platform would merely rotate to a pronounced yaw position. Similarly, if the piston 42 or the piston 48 was, somehow, caused to extend materially outwardly beyond the intended outer limit of its path of movement, the platform 20 and the other actuators therefor would not be distorted or broken;

ecause that platform would merely rotate to a pronounced yaw position. In contrast, if a second actuator extended between the pin 66 and a ball-equipped plate secured to the floor, and if the piston of that actuator or if any of the pistons 42, 48 and 60 was, somehow, caused to extend materially outwardly beyond the intended outer limit of its path of movement, the platform 20 and one or more of the other actuators therefor could be distorted or broken.

The provision of two actuators which extend between the pin 205 and the floor, and the provision of two actuators which extend between the pin 239 and the floor, can be tolerated in the motion base of FIGS. 9-11, because the cables 236 and 241 will yield to minimize distorting forces applied to the platform 190. Specifically, if the piston 216 was, somehow, caused to extend materially outwardly beyond the intended outer limit of its path of movement, the platform 190 and the other actuators therefor would not be distorted, because the cable 236 would yield and permit the pin 205, and the adjacent side of that platform, to move upwardly, inwardly and forwardly. Similarly, if the piston 243 was, somehow, caused to extend materially outwardly beyond the intended outer limit of its path of movement, the platform 190 and the other actuators therefor would not be distorted, because the cable 241 would yield and permit the pin 239, and the adjacent side of the platform, to move upwardly, inwardly and forwardly. Also, if the piston 218 or the piston 242 was, somehow, caused to extend materially outwardly beyond the intended outer limit of its path of movement, the platform 190 and the other actuators therefor would not be distorted, because the cable adjacent that piston would yield and permit the adjacent pin, and the adjacent side of that platform, to move upwardly, inwardly, and rearwardly. Furthermore, where the hydraulic motor 247 was made sufficiently powerful, the piston 210 and the cylinder 212 of the motion base of FIGS. 9-11 could be eliminated. In that event, the shafts 198 and 240, as well as the shafts 54 and 24, would be held in space by just five elements that were connected to fixed points; and redundant support of those shafts would be avoided.

Because the primary raising forces supplied to the platforms 20 and 190 are supplied, respectively, by the cylinders 94 and and by the cables 236 and 241, less horsepower is required to raise those platforms than if the primary raising forces were applied by actuators which extended upwardly from the floor to the pins at the opposite sides of those platforms. Also, by using smallerthan-usual hydraulic actuators, by using higher-than-usual hydraulic pressures, and by reducing the overall masses of the hydraulic actuators, the present invention attains higher speeds of response to the control signals supplied by the computers. Those higher speeds of response are desirable; because they can increase simulated acceleration effect and the simulated deceleration effect which the motion bases of FIGS. 1-8 and 9-11 provide, respectively, for the simulated cockpits 21 and 192.

Two hydraulic or other motors 196 and 247 are shown in FIG. 10 to provide pitch motion for the platform and for the simulated cockpit 192. However, if desired, one or the other of those motors could be omitted; and, as pointed out hereinbefore, where that is done, one of 1 7 the hydraulic actuators at the opposite side of the platform 190 can be eliminated.

Referring to FIGS. 12-15, the numeral 274 denotes one of the housings which are attachable to the cylinders 94, 102, 140, 146, 152, 174, 212, 220, 244 and 250; and, for purposes of illustration, that housing is shown attached to the cylinder 102 by machine screws 275. The various housings 274 will be attached to those cylinders adjacent the free ends of those cylinders, but will be attached to those cylinders so they will not interfere with movements of the pistons relative to those cylinders.

Bearings 276 and 278 are mounted within spaced walls of the housing 274, and those bearings are preferably antifriction bearings. A shaft 280 is rotatably supported by those bearings; and the axis of that shaft is perpendicular to the axis of movement of the piston 60 held by the cylinder 102. A hollow, flanged reel 282 is fixedly secured to the shaft 280 by a pin; and a clock-like spring 284 is mounted within that reel. One end of that spring is secured to the adjacent wall of the housing 274 by a pin 285, while the other end of that spring is secured to the hub of the reel 282 by a pin 287. That spring biases the reel 282 and the shaft 280 for clockwise rotation in FIG. 13; but that spring can yield to permit counterclockwise rotation of that reel and shaft.

The numeral 286 denotes an elongated flexible cable which has one end thereof secured to a slot 289 in one of the flanges of the reel 282. The other end of that cable passes outwardly through an elongated slot 2'91 in the housing 274, passes through the guide 293 of a level-wind mechanism that is generally denoted by the numeral 292, and is held by a connector 290. A rod 288 secures that connector, and thus secures the other end of the cable 286, to the piston 60. The level-wind mechanism 292 also includes a slotted guide rod 295, a double-threaded screw 297, and the other customary and usual components of a level-wind mechanism. A rod 288 will be secured to each of the pistons 28, 42, 48, 58, 60, 170, 210, 218, 242 and 243; and those rods will be secured to those pistons adjacent the free ends of those pistons. As a result, each cylinder will be equipped with a housing 274, each piston will be equipped with a rod 288, and a connector 290 and a cable 286 will extend between each rod 288 and each housing 274.

Whenever hydraulic fluid is supplied to a cylinder to cause the piston to move outwardly of that cylinder, the rod 288 and the connector 290 will pull on the cable 286 and force the spring 284 to yield and permit the reel 282 to rotate in the counter clockwise direction in FIG. 13. However, whenever hydraulic fluid is supplied to a cylinder to cause the piston to move inwardly of that cylinder, the spring 284 will rotate that reel in the clockwise direction and pull in the cable 286. The guide 293 of the levelwind mechanism 292 will reciprocate in the slot 291, and will thereby cause the cable 286 to wind onto the reel 282 in helical fashion; and hence the radial dimensions of all turns of that cable will be substantially equal.

The numeral 294 denotes a large diameter gear which is mounted on the shaft 280 and which is pinned to that shaft; and that gear meshes with a gear 299 which is mounted on, and which drives, the double-threaded screw 297 of the level-wind mechanism 292. A spur gear 301 rotates with the large diameter gear 294; and that spur gear meshes with a large diameter, anti back-lash gear 296 that is mounted on and pinned to the shaft 300 of a multi-turn potentiometer 298. That potentiometer is mounted Within the right-hand compartment of the housing 274; and the shaft of that potentiometer extends through an opening in the wall which subdivides that housing into two compartments. The gears 301 and 296 have a gear ratio which enables the shaft 300 of the potentiometer 298 to rotate at an angular rate which is much smaller than that at which the shaft 280 rotates. A spur gear 302 also is mounted on the shaft 300 of the multi-turn potentiometer 298; and that gear meshes with a larger diameter, anti back-lash gear 304 which is mounted on a shaft 306. The spur gear 302 and the large diameter gear 304 provide a gear ratio which enables the shaft 306 to rotate at an angular rate which is much smaller than that at which the shaft 300 rotates. A twosection cam 308 is mounted on and pinned to the shaft 306; and a limit switch 310 is mounted so the actuator thereof engages the profile of one section of that cam, and a limit switch 312 is mounted so that actuator thereof engages the profile of the other section of that cam. The two sections of the two-section cam 308 can be set in different positions relative to each other and relative to the actuators of the limit switches 310 and 312; and the positions shown for those sections in FIG. 14 do not necessarily represent the actual positions of those sections.

In the preferred embodiments of the present invention shown in FIGS. 18 and 91l, each of the pistons 28, 42, 48, 58, 60, 210, 218, 242 and 243 and its corresponding cylinder are dimensioned so that piston can move outwardly of that cylinder approximately thirteen feet. The reel 282 has a diameter of three inches, and hence that reel must rotate more than ten revolutions whenever the piston 60 moves from its fully-retracted to its fully extended-position; and that reel also must rotate more than ten revolutions whenever that piston moves from its fullyextended to its fully-retracted position. The gears 301 and 296 enable the shaft 300 of the multi-turn potentiometer 298 to rotate less than two revolutions during movement of the piston 60 from its fully-retracted to its fully-extended position or from its fully-extended to its fully-retracted position. The gears 302 and 304 enable the two -section cam 308 to rotate less than one revolution during movement of the piston 60 from its fullyretracted to its fully-extended position and from its fullyextended to its fully-retracted position. As a result, the limit switch 310 and the apropriate section of the cam 308 can be set to supply a signal to the computer when the piston 60 reaches a predetermined extended position; and the limit switch 312 and the other section of that carn can be set to supply a signal to that computer when that piston reaches a predetermined retracted position. Appropriate settings of the positions of the sections of the cam 308 relative to the actuators of the limit switches 310 and 312 can keep the piston 60 from moving so far that it creates undue stresses and possible breakage of itself or of the cylinder 102 or of the hydraulic system which drives it.

The tangential movement of the arm of the multi-turn potentiometer 298 will be proportional to the movement of the piston 60 relative to the cylinder 102. Consequently, that potentiometer will be able to develop a signal which will indicate, at any instant, the position of that piston relative to that cylinder. That signal will be fed to a servo control loop, or the like; and that servo control loop will enable a control valve to suply the proper amount of hydraulic fluid to that cylinder.

The actuators, which include the pistons 42, 48, 60, 210, 218, 242 and 243 and the cylinders 146, 152, 102, 212, 220, 244 and 250, primarily apply guiding and stabilizing forces to the pins 36, 66, 205 and 239, and thus to the platforms 20 and 190. The primary supporting and raising forces that are applied to those pins, and thus to those platforms, are supplied by the pistons 28 and 58 and the cylinders and 94 and by the cables 236 and 241. Because the pistons 28 and 58 and the cylinders 140 and 94 and the cables 236 and 241 primarily apply tensile forces, and need not apply columnar forces, to those pins, and thus to those platforms, those pistons, cylinders and cables can be lighter in weight than can the pistons and cylinders of prior motion bases. Hence, the pistons 28 and 58 and the cylinders 140 and 94 and the cables 236 and 241 can be unusually quick in responding to command signals developed by the computer.

The pin 36 constitutes a point that is held in space by three variable-length elements piston 28 and cylinder 140, piston 42 and cylinder 146, and piston 48 and cylinder 152-that are secured to three fixed points which are not colinear. Those elemetns enable that point, and the adjacent side of the platform 20, to be moved in any and all of the X, Y and Z directions in space relative to those fixed points. Because the pin 36 can be held fixed in space, the pin 66 can constitute a point that is held in space by two varable-length elementspiston 58 and cylinder 94 and piston 60 and cylinder 102--that are secured to two further tfixed points and by a fixed-length element-the platform 20-that is secured to the point constituted by the pin 36. Those two variable length elements and the movement between the pin 36 and the platform 20 enable the point constituted by the pin 66, and the adjacent side of the platform 20, to be moved in space relative to those two fixed points. Also, the two points constituted by the pins 36 and 66 can be held fixed in spaced to limit the motion of that platform to rotation about the axis which extends betwen those points. All of this means that just six elementsthe five variable-length elements constituted by the pistons 28, 42, 48, 58, and 60 and the cylinders 140, 146, 152, 94 and 102 and the fixed-length element constituted by the platform 20can fix the two points constituted by the pins 36 and 66 in space and also can move either or both of those points in any and all of the X, Y and Z directions.

Multi-turn potentiometers, similar to the multi-turn potentiometer 298, will be connected to the shafts of the winches 234 and 260 by gear trains which will enable the shafts of those multi-turn potentiometers to rotate at angular rates which are much smaller than the angular rates at which those winches rotate. As a result, one or two revolutions of the shafts of those multi-turn potentiometers will represent the pulling in or the paying out of substantial lengths of the cables 236 and 241.

Referring to FIG. 16, the numeral 320 denotes a short shaft which is similar to the short shafts 24 and 54 of the motion base of FIGS. 18. A connector 322 is dimensioned to fit loosely within the slot in the clevis-like end of the short shaft 320; and that connector has an opening 324 therein, and has pins 326 extending outwardly beyond both ends thereof. The numeral 328 denotes a piston which is similar to the pistons 28 and 58 of the motion base of FIGS. 1-8; and that piston has a yoke 330 at the lower end thereof. The arms of that yoke have aligned openings 332 therein, and those openings accommodate and telescope over the pins 326 on the connector 322. A pin 334 extends through aligned openings in the clevis-like end of the short shaft 320 and through the opening 324 in the connector 322 to hold that connector, and also the piston 328, in assembled relation with that short shaft. The piston 328 can rotate about the axis of the pins 326, and also can rotate with the connector 322 about the axis of the pin 334; and hence that piston can rotate freely, throughout a finite number of degrees, relative to the short shaft 320. The structure shown by FIG. 16 permits greater movement between the piston 328 and the short shaft 320 than the structure shown by FIG. 3 permits between the piston 28 and the short shaft 24; and hence the former structure will be preferred in many motion bases.

It will be noted that the three elements which act upon the point of support constituted by the pin 36 are differently-directed elements. Also, it will be noted that the three elements which act upon the point of support constituted by the pin 66 are differently-directed elements. Similarly, it will be noted that the three elements which act upon the point of support constituted by the pin 205 are differently-directed elements. Additionally, it will be noted that the three elements which act upon the point of support constituted by the pin 239 are differentlydirected elements. The fact that those various elements are differently-directed enables those elements to hold those points of supports fixed in space.

If the motion base of FIGS. l8 had to be located in a very low building, the outer ends of the cylinders 94 and 140 could be moved down below the lowermost posi- 2G tions of the shafts 24 and 54. However, in such event, all of the cylinders 94, 102, 140, 146 and 152 and all of the pistons 58, 60, 28, 42 and 48 should be strengthened; because the hydraulic actuators constituted by those pistons and cylinders would have to develop heavy columnar forces.

The motion bases shown in FIGS. 1-8 and 9-11 are extremely useful in supporting the simulated cockpits used in flight-simulating systems. However, those motion bases can be used to support any platforms which must be given any one or more of the six degrees of motion, namely, forward, pitch, heave, roll, yaw and slip.

The motion bases of FIGS. 1-8 and 911 have the supporting elements thereof located outwardly of the platforms 20 and 190 thereof, respectively. As a result, those platforms and the simulated cockpits carried thereby can be moved downwardly close to the floors of the buildings or structures in which those motion bases are located. In fact, the platform 190 of the motion base of FIGS. 9-11 can be rested directly upon the floor of the building or structure in which that motion base is located. Because the platforms 20 and 190 can be moved downwardly close to the floors of the buildings or structures in which the motion bases of FIGS. 18 and 9-11 are located, the users of those motion bases can readily enter and leave the simulated cockpits carried by those platforms.

While it is desirable that the axis defined by the shafts 24 and 54 pass through the center of mass of the combined platform 20 and simulated cockpit 21, that axis can be located above, below, forwardly or rearwardly of that center of mass. Similarly, while it is desirable that the axis defined by the shafts 198 and 240 pass through the center of mass of the combined platform 190 and simulated cockpit 192, that axis can be located above, below, forwardly or rearwardly of that center of mass. In fact, if desired, either of those axes could be located below the bottom of the corresponding platform.

If desired, standard universal joints could be substituted for the ball and clamp connections provided between the plates 98, 142, 148, 168, 216, 224, 248 and 254 and the cylinders 102, 146, 152, 164, 212, 220, 244 and 250, respectively. Similarly, standard universal joints could be substituted for the connections between the caps and 134 and the cylinders 94 and 140.

Whereas the drawing and accompanying description have shown and described two preferred embodiments of the present invention, it should be apparent to those skilled in the art that various changes may be made in the form of the invention without affecting the scope thereof.

What we claim is:

1. A motion base that comprises: a platform, a point of support for said platform, a second point of support for said platform, three differently-directed means acting upon the first said point of support to hold said first said point of support, and thus the adjacent portion of said platform, in space, three further differently-directed means acting upon said second point of support to hold said second point of support, and thus the nearby portion of said platform, in space, the first said and said second points of support for said platform essentially defining a line in space, said platform being rotatable about said line with said line serving as the axis of rotation for said platform, and means to selectively prevent or permit rotation of said platform about said line with said line serving as the axis of rotation for said platform, the first said and said second points of support and the first said three differently-directed means and said three further differently-directed means normally constituting essentially the sole support for said platform, the first said three differently-directed means being capable of independent movement and being spatially mounted to move said first said point of support and said adjacent portion of said platform in the X, Y or Z direction, said three further differently-directed means 21 being capable of independent movement and being spatially mounted to move said second point of support and said nearby portion of said platform in the X, Y or Z direction.

2. A motion base that comprises: a platform, a point of support for said platform, a second point of support for said platform, three differently-directed means acting upon the first said point of support to hold said first said point of support, and thus the adjacent portion of said platform, in space, three further differently-directed means acting upon said second point of support to hold said second point of support, and thus the nearby portion of said platform, in space, the first said and said second points of support for said platform essentially defining a line in space, said platform being rotatable about said line with said line serving as the axis of rotation for said platform, and means to selectively prevent or permit rotation of said platform about said line with said line serving as the axis of rotation for said platform, the first said and said second points of support and the first said three differently-directed means and said three further differently-directed means normally constituting essentially the sole support for said platform, the first said three differently-directed means being capable of independent movement and being spatially mounted to move said first said point of support and said adjacent portion of said platform in the X, Y or Z direction, said three further differently-directed means being capable of independent movement movement and being spatially mounted to move said second point of support and said nearby portion of said platform in the X, Y or Z direction, said platform being rotatable about said line while the first said and said second points of support are essentially stationary, and said platform also being rotatable about said line while said first said or said second point of support is being moved.

3. A motion base as claimed in claim 1 wherein said first said three differently-directed means can move said first said point of support into and out of positions which are in register with the position of said second point of support, and wherein said three further differently-directed means can move said second point of support into and out of positions Wrich are in register with the position of said first said point of support.

4. A motion base as claimed in claim 1 wherein said first said point of support is a pin which is carried by a shaft that is rotatable relative to said platform, and wherein said second point of support is a second pin which is carried by a second shaft that is rotatable relative to said platform.

5. A motion base that comprises: a platform, a point of support for said platform, a second point of support for said platform, three diiferently-directed means acting upon the first said point of support to hold said first said point of support, and thus the adjacent portion of said platform, in space, three further differently-directed means acting upon said second point of support to hold said second point of support, and thus the nearby portion of said platform, in space, the first said and said second points of support for said platform essentially defining a line in space, said platform being rotatable about said line with said line serving as the axis of rotation for said platform, and means to selectively prevent or permit rotation of said platform about said line with said line serving as the axis of rotation for said platform, the first said and said second points of support and the first said three differentlydirected means and said three further differently-directed means normally constituting essentially the sole support for said platform, the first said three differently-directed means being capable of independent movement and being spatially mounted to move said first said point of support and said adjacent portion of said platform in the X, Y or Z direction, said three further differently-directed means being capable of independent movement and being spatially mounted to move said second point of support and said nearby portion of said platform in the X, Y or Z 2.2 direction, said first said three ditferently-directed means including three hydraulic actuators, said three further differently-directed means including two hydraulic actuators and said platform, and each of said hydraulic actuators comprising a piston and a double-acting cylinder.

6. A motion base that comprises: a platform, a point of support for said platform, a second point of support for said platform, three differently-directed means acting upon the first said point of support to hold said first said point of support, and thus the adjacent portion of said platform, in space, three further differently-directed means acting upon said second point of support to hold said second point of support, and thus the nearby portion of said platform, in space, the first said and said second points of support for said platform essentially defining a line in space, said platform being rotatable about said line with said line serving as the axis of rotation for said platform, and means to selectively prevent or permit rotation of said platform about said line with said line serving as the axis of rotation for said platform, the first said and said second point of support and the first said three differently-directed means and said three further differently-directed means normally constituting essentially the sole support for said platform, the first said three differently-directly means being capable of independent movement and being spatiall mounted to move said first said points of support and said adjacent portion of said platform in the X, Y or Z direction, said three further differently-directly means being capable of independent movement and being spatially mounted to move said second point of support and said nearby portion of said platform in the X, Y or Z direction, said first said three differently-directed means including three variable-length elements that extend between said first said point of support and three fixed points, and said three further differently-directed means including two variable-length elements that extend between said second point of support and two further fixed points, whereby said motion base can be supported and moved in space by connections to just five fixed points.

7. A motion base as claimed in claim 1 wherein said first said point of support is adjacent one side of said platform, wherein said second point of support is adjacent the opposite side of said platform, and wherein said line which is defined by said points of support extends transversely of said platform.

8. A motion base that comprises: a platform, a point of support for said platform, a second point of support for said platform, three differently-directed means acting upon the first said point of support to hold said first said point of support, and thus the adjacent portion of said platform, in space, three further differently-directed means acting upon said second point of support to hold said second point of support, and thus the nearby portion of said platform, in space, the first said and said second points of support for said platform essentially defining a line in space, said platform being rotatable about said line with said line serving as the axis of rotation for said platform, and means to selectively prevent or permit rotation of said platform about said line with said line serving as the axis of rotation for said platform, the first said and said second points of support and the first said three differently-directed means and said three further differently-directed means normally constituting essentially the sole support for said platform, the first said three differently-directed means being capable of independent movement and being spatially mounted to move said first said point of support and said adjacent portion of said platform in the X, Y or Z direction, said three further differently-directed means being capable of independent movement and being spatially mounted to move said second point of support and said nearby portion of said platform in the X, Y or Z direction, one of said first said three differently-directed means applying tensile forces to said first said point of support, and one 23 l of said three further differently-directed means applying tensile forces to said second point of support.

9. A motion base that comprises: a platform, a point of support for said platform, a second point of support for said platform, three differently-directed means acting upon the first said point of support to hold said first said point of support, and thus the adjacent portion of said platform, in space, three further differently-directed means acting upon said second point of support to hold said second point of support, and thus the nearby portion of said platform, in space, the first said and said second points of support for said platform essentially defining a line in space, said platform being rotatable about said line with said line serving as the axis of rotation for said platform, and means to selectively prevent or permit rotation of said platform about said line with said line serving as the axis of rotation for said platform, the first said and said second points of support and the first said three differently-directed means and said three further differently-directed means normally constituting essentially the sole support for said platform, the first said three differently-directed means being capable of independent movement and being spatially mounted to move said first said point of support and said adjacent portion of said platform in the X Y or Z direction, said three further differently-directed means being capable of independent movement and being spatially mounted to move said second point of support and said nearby portion of said platform in the X, Y or Z direction, one of said first said three differently directed means including a flexible cable that applies a force to said first said point of support and including means to support and move said flexible cable, and said three further differently-directed means including a second flexible cable that applies a force to said second point of support and including means to support and move said second flexible cable.

10. A motion base that comprises: a platform, a point of support for said platform, a second point of support for said platform, three differently-directed means acting upon the first said point of support to hold said first said point of support, and thus the adjacent portion of said platform, in space, three further differently-directed means acting upon said second point of support to hold said second point of support, and thus the nearby portion of said platform, in space, the first said and said second points of support for said platform essentially defining a line in space, said platform being rotatable about said line with said line serving as the axis of rotation for said platform and means to selectively prevent or permit rotation of said platform about said line with said line serving as the axis of rotation for said platform, the first said and said second points of support and the first said three differently-directed means and said three further differently-directed means normally constituting essentially the sole support for said platform, the first said three dilferently-directed means being capable of independent movement and being spatially mounted to move said first said point of support and said adjacent portion of said platform in the X, Y or Z direction, said three further differently-directed means being capable of independent movement and being spatially mounted to move said second point of support and said nearby portion of said platform in the X, Y or Z direction, said first said three differently-directed means including an element that is connected to a fixed point which is located above the level of said first said point of support, and said three further differently-directed means including a second element that is connected to a second fixed point which is located above the level of said second point of support.

11. A motion base as claimed in claim 1 wherein connecting means between said first said point of support and said first said three differently-directed means permits universal movement of the portion of said platform ad- 24 jacent said first said point of support, and wherein further connecting means between said second point of support and at least two of said three differently-directed means permits universal movement of the portion of said platform adjacent said second point of support.

12. A motion base as claimed in claim 1 wherein said platform has a load thereon and movable therewith, and wherein said line extends through the approximate center of mass of said combined platform and load.

13. A motion base as claimed in claim 1 wherein said platform has a plurality of legs depending downwardly therefrom, wherein said legs hold said platform solidly in a predetermined position whenever said motion base is at rest, and wherein said legs enable said platform to fail safe in the event any of said first said three differently-directed means or any of said three further differently-directed means should fail.

14. A motion base as claimed in claim 1 wherein said motion-preventing and motion-permitting means is a motor that rotates said platform relative to said points of support, said motor being mounted on and movable with said platform.

15. A motion base as claimed in claim 1 wherein said first said three differently-directed means and said three further differently-directed means provide non-redundant support for said platform, whereby said platform can move and be free of destructive forces in the event any of said first said three differently-directed means or any of said three further differently-directed means causes said adjacent portion or said nearby portion of said platform to move an excessive distance.

16. A motion base as claimed in claim 1 wherein said platform is one of said three further differently-directed means that act upon said second point of support.

17. A motion base as claimed in claim 1 wherein said first said three differently-directed means enable said latform to move and thereby be free of destructive forces in the event said three further differently-directed means cause said nearby portion of said platform to move an excessive distance, and wherein said three further difierent-directed means enable said platform to move and thereby be free of destructive forces in the event said first said three differently-directed means cause said adjacent portion of said platform to move an excessive distance.

18. A motion base that comprises: a platform, a point of support for said platform, a second point of support for said platform, three differently-directed means acting upon the first said point of support to hold said first said point of support, and thus the adjacent portion of said platform, in space, three further differently-directed means acting upon said second point of support to hold said second point of support, and thus the nearby portion of said platform, in space, the first said and said second points of support for said platform essentially defining a line in space, said platform being rotatable about said line with said line serving as the axis of rotation for said platform, and means to selectively prevent or permit rotation of said platform about said line with said line serving as the axis of rotation for said platform, the first said and said second points of support and the first said three differently-directed means and said three further ditferently-directed means normally constituting essentially the sole support for said platform, the first said three differently-directed means being capable of independent movement and being spatially mounted to move said first said point of support and said adjacent portion of said platform in the X, Y and Z direction, said three further differently-directed means being capable of independent movement and being spatially mounted to move said second point of support and said nearby portion of said platform in the X, Y or Z direction, a tripod that is mounted adjacent said first said point of support and that extends above the level of said first said point of support, a second tripod that is mounted adjacent said second point of support and that extends above said second point of support, said first said three differently-directed means including an element that is connected to a fixed point on the first said tripod which is located above the level of said first said point of support, and said three further differently-directed means including a second element that is connected to a second fixed point on said second tripod which is located above the level of said second point of support.

-19. A motion base as claimed in claim 1 wherein a pit is provided below and generally in register with said platform, said pit being dimensioned to accommodate the forward end or the rear end of said platform, the first said three differently-directed means extending outwardly from said first said point of support to points located outwardly beyond said pit, at least two of said three further differently-directed means extending outwardly from said second point of support to points located outwardly beyond said pit.

20. A motion base as claimed in claim 1 wherein a pit is provided below and generally in register with said platform, said pit being dimensioned to accommodate the forward end or the rear end of said platform, the first said three differently-directed means extending outwardly from said first said point of support to points located outwardly beyond said pit, at least two of said three further differently-directed means extending outwardly from said second point of support to points located outwardly beyond said pit, and wherein supporting means within said pit underlies portions of said platform intermediate said front end and said rear end of said platform and can hold and support said portions of said platform.

21. A motion base that comprises: a platform, a point of support for said platform, a second point of support for said platform, three differently-directed means acting upon the first said point of support to hold said first said point of support, and thus the adjacent portion of said platform, in space, three further differently-directed means acting upon said second point of support to hold said second point of support, and thus the nearby portion of said platform, in space, the first said and said second points of support for said platform essentially defining a line in space about which said platform can be moved in pitch, said platform being movable in pitch about said line with said line serving as the axis of pitch rotation for said platform, and means to selectively prevent or permit rotation of said platform about said line with said line serving as the axis of pitch rotation for said platform, the first said and said second points of support normally constituting essentially the sole support for said platform, the first said three differently-directed means being capable of independent movement and extending outwardly from said first said point of suppolt to points of securement spaced outwardly of said first said point of said support, said three further diiferently-directed means being capable of independent movement and at least two of said three further differently-directed means extending outwardly from said second point of support to further points of securement spaced outwardly of said second point of support.

22. A motion base as claimed in claim 21 wherein at least one of the first said three differently-directed means extends upwardly from said first said point of support to a supporting member which is located above the level of said first said point of said support, and at least one of said three further differently-directed means extending upwardly from said second point of support to a supporting member which is located above the level of said second point of support, said one of said first said three differently-directed means acting in tension, said one of said three further differently-directed means acting in tension.

23. A motion base as claimed in claim 21 wherein said points of securement to which the first said three differently-directed means are disposed outwardly of said platform whereby no portion of any of said first said three differently-directed means underlies said platform and wherein said further points of securement to which said two of said three further differently-directed means are disposed outwardly of said platform, whereby no portion of any of said two of said three further differently-directed means underlies said platform, whereby said platform can be moved close to the floor or ground.

References Cited UNITED STATES PATENTS 3,281,962 11/1966 Pancoe 3S-12 3,295,224 1/1967 Cappel 35l2 EUGENE R. CAPOZIO, Primary Examiner P. V. WILLIAMS, Assistant Examiner US. Cl. XJR. 248396

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