Abstract
A vehicle nonlinear dynamics experimental simulation device, such as flight simulator, including a motorized spherical vehicle suspended inside a spherical shell which has a smooth inner surface. The spherical vehicle is supported by a plurality of spiky legs with bearing assemblies. The spherical shell is supported by three controllable translational motion platforms. Simulating apparatuses for a pilot cabin is mounted inside the spherical vehicle. The spherical vehicle has driving, restoring, and damping capabilities in roll, pitch, and yaw directions and is capable of unbounded rotation in any directions. The spherical vehicle provides an experimental model to simulate a vehicle's rotational dynamics.
Claims
1. A motion simulating device comprising: a. a spherical shell with a smooth inner surface mounted on the ground; b. a spherical vehicle suspending within said spherical shell, wherein said spherical vehicle including a plurality of ring beams for forming a base truss of said spherical vehicle; c. a plurality of bearing assemblies located around an exterior of said ring beams for suspending said spherical vehicle within said spherical shell, wherein each bearing assembly includes a bearing and a support post which is connected on one end to said exterior of said ring beams and on an other end to said bearing; d. a plurality of driving assemblies located around said exterior of said ring beams for rotationally driving said vehicle with respect to roll, pitch, and yaw axes of said vehicle, wherein each driving assembly includes motor-driven omni wheels and a linear actuator; e. a plurality of restoring assemblies located around said exterior of said ring beams for rotationally restoring positions of said vehicle with respect to said vehicle's roll, pitch, and yaw axes, wherein each restoring assembly includes restoring omni wheels, a rotational spring, and a linear actuator; f. a plurality of damping assemblies connectable to said restoring omni wheels for damping said vehicle's motions with respect to said vehicle's roll, pitch, and yaw axes, wherein each damping assembly includes a rotational damper and a shift gear mechanism controlled by a linear actuator for engaging and disengaging said damper; and g. a simulating pilot cabin mounted within said spherical vehicle.
2. The motion simulating device of claim 1 further comprising a means for controlling said linear actuators to adjust the normal forces between said omni wheels and said smooth inner surface of said spherical shell.
3. The motion simulating device of claim 1 wherein said bearings comprise air bearings and at least one air compressor.
4. The motion simulating device of claim 1 wherein said bearings comprise omni-directional ball bearings.
5. The motion simulating device of claim 1 further comprising a shell screen mounted on an inside of said ring beams for visual simulation purpose.
6. A motion simulating device comprising: a. a spherical shell which has a smooth inner surface and mounted on three controllable translational motion platforms; b. a spherical vehicle suspending within said spherical shell, wherein said spherical vehicle including a plurality of ring beams for forming a base truss of said spherical vehicle; c. a plurality of bearing assemblies located around an exterior of said ring beams for suspending said spherical vehicle within said spherical shell, wherein each bearing assembly includes a bearing and a support post which is connected on one end to said exterior of said ring beams and on an other end to said bearing; d. a plurality of driving assemblies located around said exterior of said ring beams for rotationally driving said vehicle with respect to roll, pitch, and yaw axes of said vehicle, wherein each driving assembly includes motor-driven omni wheels and a linear actuator; e. a plurality of restoring assemblies located around said exterior of said ring beams for rotationally restoring positions of said vehicle with respect to said vehicle's roll, pitch, and yaw axes, wherein each restoring assembly includes restoring omni wheels, a rotational spring, and a linear actuator; f. a plurality of damping assemblies connectable to said restoring omni wheels for damping said vehicle's motions with respect to said vehicle's roll, pitch, and yaw axes, wherein each damping assembly includes a rotational damper and a shift gear mechanism controlled by a linear actuator for engaging and disengaging said damper; and g. a simulating pilot cabin mounted within said spherical vehicle.
7. The motion simulating device of claim 6 further comprising a means for controlling said linear actuators to adjust the normal forces of between said omni wheels and said smooth inner surface of said spherical shell.
8. The motion simulating device of claim 6 wherein said bearings comprise air bearings and at least one air compressor.
9. The motion simulating device of claim 6 wherein said bearings comprise omni-directional ball bearings.
10. The motion simulating device of claim 6 further comprising a shell screen mounted on an inside of said ring beams for visual simulation purpose.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The following descriptions of drawings of the preferred embodiments are merely exemplary in nature and are not intended to limit the scope of the invention, its applications, or uses in anyway.
(2) FIG. 1 is a perspective view of the nonlinear vehicle dynamically equivalent simulator with a quarter portion cut-out of the spherical shell to allow a view of the inside structures of the simulator.
(3) FIG. 2 is a side view of the simulator shown in FIG. 1.
(4) FIG. 3 is a top view of the simulator shown in FIG. 1.
(5) FIG. 4 is a front view of the simulator shown in FIG. 1.
(6) FIG. 5 is an exploded view of the spherical shell and the supporting hydraulic platform with controllable vertical motion capability.
(7) FIG. 6 is a section view of the spherical shell and its supporting structure.
(8) FIG. 7 is an exploded view of the spherical shell shown in FIG. 6.
(9) FIG. 8a and FIG. 8b are perspective views at different angles for a supporting structure panel of the spherical shell.
(10) FIG. 9 is a perspective view of the spherical skeleton with spike-type supports.
(11) FIG. 10 is a side view of the spherical skeleton shown in FIG. 9.
(12) FIG. 11 is a front view of the spherical skeleton shown in FIG. 9.
(13) FIG. 12 is a top view of the spherical skeleton shown in FIG. 9.
(14) FIG. 13a is a perspective view of the spherical skeleton structure with a reference cube inside the skeleton. FIG. 13b is a perspective view of the spherical skeleton without the reference cube. FIG. 13c is a perspective section view of a typical frame constructing the spherical skeleton. FIG. 13d is a rear view of a typical four-frame joint of the spherical skeleton. FIG. 13e is a rear view of a typical three-frame joint of the spherical skeleton.
(15) FIG. 14 is an exploded view of a spike-type support of an air bearing assembly.
(16) FIG. 15 is a zoom-in perspective view of the spherical skeleton with a driving assembly, a restoring and damping assembly, and two spike-type supports of air bearing assemblies.
(17) FIG. 16 is a perspective view of a driving assembly with a pair of omni wheels.
(18) FIG. 17 is a perspective view of a restoring and damping assembly with a pair of omni wheels.
(19) FIG. 18 is a perspective view of a restoring and damping assembly from an angle different with that in FIG. 17.
(20) FIG. 19a is a perspective view of inside structures of a restoring and damping assembly shown in FIG. 18. FIG. 19b is a perspective view of a restoring and damping assembly showing a spring mounting mechanism. FIG. 19c is a section view of A-A plane in FIG. 19b to show details of the spring mounting mechanism for the restoring and damping assembly.
(21) FIG. 20 is an exploded and zooming view of the restoring and damping assembly shown in FIG. 18.
(22) FIG. 21a is a perspective inside view of the restoring and damping assembly shown in FIG. 18 and FIG. 19a. FIG. 21b is an exploded view of a restoring and damping assembly. FIG. 21c is another exploded view showing a damping assembly.
(23) FIG. 22a is a perspective view of a door assembly with the door open. FIG. 22b is a perspective view of the door assembly with the door closed.
(24) FIG. 23a is a perspective view of the top portion of the door assembly. FIG. 23b is a perspective view of the bottom portion of the door assembly.
(25) FIG. 24 is a perspective view of a pilot cabin of the simulator.
(26) FIG. 25 is a perspective view of the spherical skeleton with a shell type screen for visualization.
(27) FIG. 26a is a perspective view of a ball wheel assembly which may be used to replace the air bearing assembly shown in FIG. 14. FIG. 26b is a side view of the ball wheel assembly.
DETAILED DESCRIPTION OF THE EMBODIMENTS
(28) The underlying idea of the present invention is to provide a simulator, as shown in FIG. 1, which can be used to do experimental simulations for vehicle nonlinear dynamics. A spherical vehicle 109 is suspended inside a spherical shell made of a top half shell 107 and a bottom half shell 106. The spherical shell is supported by a vertically movable hydraulic piston 105 and four linear actuators 104a, 104b, 104c (FIG. 2) and 104d (FIG. 4). The piston 105 is mounted on top and in the center of a horizontal movable platform 103 which has a plurality of wheels at its bottom. These wheels are movable along a plurality of rails 111 and driven by electrical motors (not shown) controlled by a control system of the simulator. These rails 111 are parallel and mounted equally spaced on top of a platform 102 which is larger than the platform 103 and has a plurality of wheels at its bottom. These wheels are movable along a plurality of rails 110 and driven by electrical motors (not shown) controlled by the control system of the simulator. These rails 110 are parallel and mounted equally spaced on top of a platform 101 which is larger than the platform 102. The orientations of the rails 111 and the rails 110 are orthogonal. Therefore, three translational motions, i.e. surge, sway, and heave are provided by the platforms 103, the platform 102, and the piston 105, respectively. On the top half shell 107, there is a sliding door assembly 108 capable to be opened from outside of the spherical shell to let people in and out of the spherical vehicle 109. FIG. 2 is a side view of the simulator shown in FIG. 1 with the door open showing a pilot cabin. A vertical movable supporting platform includes the piston 105, a round platform 112, and a bowl-like supporting structure 113. A set of screen 114 may be used for showing the virtual reality view of simulations. The platform 101 is on a flat ground of a room which is housing the simulator. FIG. 3 and FIG. 4 are a top view and a front view of the simulator, respectively, showing detailed layouts. A plurality of air bearing assemblies 115, shown in FIG. 2 and FIG. 4, are mounted on ring beams of the spherical vehicle 109.
(29) Detailed layouts of the spherical shell and its supporting structures are given in FIG. 5, FIG. 6, FIG. 7, FIG. 8a and FIG. 8b. The bottom half spherical shell 106 shown in FIG. 5 includes an outer layer 106a, a round apex outer layer 106c, and an inner seamless thin shell layer of half sphere 106b as shown in FIG. 6. The outer layer 106a includes 16 identical panels each of which looks like panel 106a-1 shown in FIG. 8a and FIG. 8b. These 16 panels are fastened together by bolts through outside frames of the panels as shown in FIG. 8a and FIG. 8b and also fasten together with the round apex outer layer 106c by a plurality of bolts to form a solid bottom half spherical shell (106a and 106c). Preferably, the outer layer panels are made of fiber-reinforced composite materials or the like to provide light weight and enough strength to support the inner thin layer 106b and in turn to support weights of the spherical vehicle, and the inner thin layer 106b is to be made of airtight and hard materials such as fiber-reinforced composite materials or the like, or even metals like aluminum or stainless steel if necessary. The top half spherical shell 107 has similar structures as the bottom half spherical shell 106. The bowl-like supporting structure 113 as shown in FIG. 5, FIG. 6, and FIG. 7 is mounted on the platform 112 by a plurality of vertical screws. The outer layer 106a, the round apex outer layer 106c, and the bowl-like supporting structure 113 are fastened together by a plurality of horizontal bolts as shown in FIG. 6. The half sphere seamless thin layer 106b is bonded with the half outer layer spherical shell (106a and 106c) as shown in FIG. 7 to form the solid half spherical shell 106. The top half spherical shell 107 has a similar structure as the bottom shell 106 and joints 106 by bolts through frames along the great circle as shown by FIG. 5 to form a complete solid spherical shell which has an airtight and extremely smooth inner surface.
(30) Referring to FIG. 9, FIG. 10, FIG. 11, FIG. 12, FIG. 13a, FIG. 13b, FIG. 13c, FIG. 13d, and FIG. 13e, the spherical vehicle 109 includes a spherical skeleton 121 shown in FIG. 13a and FIG. 13b, 14 air bearing assemblies 115 (FIG. 9 and FIG. 10), six drive assemblies 117a, 117b, 117c, 117d, 117e, and 117f (FIG. 9), six restoring and damping assemblies 116a, 116b, 116c, 116d, 116e, and 116f (FIG. 9), a pilot cabin support platform 119, pilot models 118, a dashboard 120, and the screens 114 as shown in FIG. 9 and FIG. 10. The spherical vehicle also contains all necessary apparatuses (not shown) for suspending the spherical vehicle, controlling, and operating the vehicle such as air compressors, batteries, computers, even oxygen tanks (if necessary) and etc. The spherical skeleton 121 (FIG. 13a and FIG. 13b) includes a plurality of ring beams. There are nine ring beams in the example (FIG. 13a and FIG. 13b). Preferably, these ring beams are made of fiber-reinforced composite materials or light metal such as aluminum to provide strong bending strength and light weight. Radiuses of all the ring beams are same. All these ring beams are within the circumscribing sphere of a tetrakis hexahedron based on an inside cube shown in FIG. 13a. The tetrakis hexahedron may be imagined as the inside cube with pyramids on each face. An apex of each pyramid coincides with the center of a four-ring-beam joint (FIG. 13d). There are 6 such four-ring-beam joints which are also located on X, Y, and Z axes as shown in FIG. 13a. Three ring beams are located on the XOY, YOZ, and XOZ planes, respectively, as shown in FIG. 13a. The orientations of the other six ring beams may be found by rotating the above three ring beams 45 about X, Y, and Z axes, respectively. Each ring beam includes two sub-ring beams with U-type cross sections as shown in FIG. 13c. The two sub-ring beams are bonded together side by side to form a solid ring beam in order to provide more bending strength in the middle line as shown in FIG. 13c. The nine ring beams are connected with each other to form the solid spherical skeleton 121 as a base truss for the spherical vehicle as shown in FIG. 13b. FIG. 13d is an underneath view showing a typical joint of four ring beams. FIG. 13e is an underneath view showing a typical joint of three ring beams.
(31) Referring to FIG. 14, each of the air bearing assemblies 115 includes a support post 115d, a ball connector 115b, and a convex spherical air bearing 115a with an air inlet 115c. The air bearing assemblies are mounted radially outward on the ring beams which construct the skeleton for the spherical vehicle. Preferably, there are 14 identical air bearing assemblies as shown in FIG. 9, FIG. 10, FIG. 11, and FIG. 12. These air bearings are located at the locations of the 14 vertices of the tetrakis hexahedron (not shown) mentioned above. Each air bearing is made of porous materials and has a convex spherical curved surface which matches that of the inner surface of the spherical shell. High pressure air from on-board air compressors (not shown) is supplied through a hose (not shown) connecting to the air inlet 115c into the air bearing 115a to form a thin layer of air between 115a and the inner surface of the spherical shell. The size of the air bearing 115a determined by the total weight of the spherical vehicle is large enough to provide support to suspend the spherical vehicle when all the 14 air bearings are working at same time. The 14 air bearing assemblies are distributed around the outside of the spherical vehicle in such a way that the spherical vehicle may be suspended inside of the spherical shell to allow frictionless motions for the spherical vehicle.
(32) While the embodiment in FIG. 9 shows the use of 14 air bearing assemblies, it will be understood by one of skill in the art that a small or a larger number of air bearing assemblies could also be used to support the spherical vehicle such as, for example, 12 air bearing assemblies located at the vertices of an icosahedron on which a spherical skeleton is based and in this case the three orthogonal ring beams described above located on the XOY, YOZ, and XOZ planes are still needed.
(33) The four-ring-beam joint in FIG. 13d provides a supporting structure in the spherical skeleton with the strongest bending strength. There are six such four-ring-beam joints in the spherical skeleton. There are six driving assemblies and six restoring and damping assemblies. A typical driving assembly 117c and a typical restoring and damping assembly 116c are located close to a four-ring-beam joint shown in FIG. 15. Similarly, the other five driving assemblies and the other five restoring and damping assemblies are located close to the other five four-ring-beam joints, respectively. The six driving assemblies and the six restoring and damping assemblies are mounted on the three ring beams which are located in the XOY, XOZ, and YOZ planes, respectively. Therefore, these three ring beams are orthogonal to each other as shown in FIG. 13a.
(34) The driving assembly 117c includes an electrical right-angle DC motor 117c-1, a pinned support 117c-5 to restrict tangential and normal movements of the motor on a ring beam but to allow a rotational movement, two identical omni wheels 117c-2 and 117c-3 which are paired up and symmetrically located on each side of the right-angle DC motor as shown in FIG. 16 to provide power for rotational movements of the spherical vehicle, a linear actuator 117c-4 and a pinned support 117c-6 supporting 117c-4 on one end. The other end (not shown) of the linear actuator 117c-4 is connected to a pinned support (not shown) mounted on the outside surface of the square casing of the DC motor 117c-1 to control the rotation of the driving assembly 117c about the pinned support 117c-5 in order to contact and to detach the inner surface of the spherical shell. The pinned supports 117c-5 and 117c-6 are aligned with the centerline of the ring beam as shown in FIG. 15. The omni wheels are specially designed to have continuous alternate rollers (e.g. German patent DE822660) to allow smooth movements for the spherical vehicle. The rollers are made of material that provides excellent traction and control. Rotations (RPM) of the omni wheels are controlled by the DC motors. The normal force of the omni wheels on the inner surface of the spherical shell is controlled by the linear actuator 117c-4. The RPM of the omni wheels and the normal force of the omni wheels on the inner surface are adjustable to provide a desired moment on the spherical vehicle. The driving assemblies 117c and 117d shown in FIG. 10 are two identical driving units mounted on the ring beam which is in the XOZ plane. These two driving units are paired up and diametrically opposed to each other on the ring beam with the omni wheel rotation axes parallel to the pitch axis of the spherical vehicle as shown in FIG. 10 in order to provide pitch moments on the spherical vehicle. Other driving assemblies 117a and 117b (FIG. 11), 117e and 117f (FIG. 12) are mounted in structures in a similar way as that for 117c and 117d. More specifically, the driving assemblies 117a and 117b are paired up and mounted on the ring beam within the YOZ plane and in the orientation to provide roll moments on the spherical vehicle as shown in FIG. 11 while the driving assemblies 117e and 117f are paired up and mounted on the ring beam within the XOY plane and in the orientation to provide yaw moments on the spherical vehicle as shown in FIG. 12.
(35) Referring to FIG. 17, the restoring and damping assembly 116c includes a cylindrical casing 116c-1, a square casing 116c-7, a pinned support 116c-5 to restrict tangential and normal movements of the assembly on a ring beam but to allow a rotational movement, two identical omni wheels 116c-2 and 116c-3 which are symmetrically located on each side of the square casing 116c-7 to provide restoring and damping power for rotational movements of the spherical vehicle, a linear actuator 116c-4, a pinned support 116c-6 supporting 116c-4, and a pinned support 116c-8. The pinned supports 116c-5 and 116c-6 are aligned with the centerline of the ring beam as shown in FIG. 15. The linear actuator 116c-4 is to control the rotation movement of the restoring and damping assembly 116c about the pinned support 116c-5 in order to contact the inner surface of the spherical shell. The omni wheels are connected to a rotational damper 131 (FIG. 19a) inside the square casing 116c-7 through a shaft 126 (FIG. 18) and are also connected to a machined rotational spring 128 (FIG. 19a) through bevel gears inside the square casing 116c-7 shown in FIG. 18. The restoring and damping assemblies 116c and 116d as shown in FIG. 10 are two identical assemblies and mounted on a ring beam which is in the XOZ plane. These two assemblies are paired up and diametrically opposed to each other on the ring beam with the omni wheel rotation axes parallel to the pitch axis of the spherical vehicle as shown in FIG. 10 in order to provide restoring and damping pitch moments on the spherical vehicle. Other restoring and damping assemblies 116a and 116b (FIG. 11), 116e and 116f (FIG. 12) are mounted in structures in a similar way as that for 116c and 116d. More specifically, the restoring and damping assemblies 116a and 116b are paired up and mounted on the ring beam within the YOZ plane and in the orientation to provide roll restoring and damping moments on the spherical vehicle as shown in FIG. 11 while the restoring and damping assemblies 116e and 116f are paired up and mounted on the ring beam within the XOY plane and in the orientation to provide yaw restoring and damping moments on the spherical vehicle as shown in FIG. 12. The restoring and damping assemblies 116a, 116b, 116c, 116d, 116e, and 116f contact the inner surface of the spherical shell at all the time during operation of the spherical vehicle. Therefore, the rotational movements of the omni wheels are passive subject to the rotational movements of the spherical vehicle, the rotational springs, and the rotational dampers. The omni wheels of the restoring and damping assemblies are identical with the omni wheels of the driving assemblies.
(36) Referring to FIG. 18, the square casing 116c-7 has a circular opening connecting to the cylindrical casing 116c-1 and a lid 123 on which a linear actuator 124 is mounted. The cylindrical casing 116c-1 also has a lid 122. The rotational spring 128 is installed inside the cylindrical casing 116c-1 as shown in FIG. 19a and FIG. 19b. One end of 128 is connected to 116c-1 through two bolt mechanisms 132a and 132b which are smoothly slidable in slots 161a and 161b (not shown), respectively as shown in FIG. 19b and FIG. 19c. The two slots 161a and 161b (not shown) are diametrically opposed to each other and located longitudinally in the inside surface of 116c-1. The two slots 161a and 161b (not shown) are about half depth of the shell thickness of 116c-1 with certain length and width depending on the characteristics of the spring 128 to restrict the rotational motion of the spring 128 on this end but to release longitudinal stress created during rotational movements of the spring 128. A section view of A-A plane in FIG. 19b is given in FIG. 19c to show the detailed layout of the mechanism. Another end of the spring 128 is fastened to a shaft 136 as shown in FIG. 19c. The shaft 136 is fixed in place by a ball bearing 129 (FIG. 19a, FIG. 21a, and FIG. 21b) in a wall of the square casing 116c-7 (FIG. 18) and is connected to the shaft 126 by bevel gears 139 and 140 as shown in FIG. 21b to transfer the rotational motions between the shaft 126 and the shaft 136. Although straight bevel gear is demonstrated in FIGS. 21b and 21c, other bevel gears could be used, such as Zerol, spiral, or hypoid bevel gears. The two omni wheels are installed rigidly on the two ends of the shaft 126 as shown in FIG. 18. In such way, rotational kinetic energy of the omni wheels 116c-2 and 116c-3 (FIG. 18) is transferred to potential energy of the spring 128 (FIG. 19a, FIG. 21b) and vice versa.
(37) The rotational damper 131 with a center hole which is larger than the shaft 126 and has a synchronizer cone teeth arrangement as shown in FIG. 21b and FIG. 21c. The damper 131 is supported by two larger radial ball bearings 130a and 130b so that it suspends over the shaft 126 as shown in FIG. 21a. As shown in FIG. 21b and FIG. 21c, a hub 141 is fixed to the shaft 126, and a sleeve 142 that is free to slide over the hub 141 is connected with a shift fork 143. A synchronizer ring 144 is located between the sleeve 142 and the damper 131 as shown in FIG. 21b and FIG. 21c. The shift fork 143 is fixed to a shift rod 134 (FIG. 21a) which is controlled by the linear actuator 124 through a connector 127. The shift rod 134 is slidable through two holes one of which is in a partition wall 133 (FIG. 21a and FIG. 21b) and another hole is in a ring support 137 (FIG. 21a) which is fixed on the inside surface (not shown) of the lid 123 (FIG. 20). There is a ball bearing in the partition wall 133 to support the shaft 126 (FIG. 21b). A partition wall 138 (FIG. 21a) with a ball bearing is used to support the shaft 136. The connector 127 as shown in FIG. 20 links the shift rod 134 (FIG. 21a) inside the square casing 116c-7 (FIG. 17) to the linear actuator 124 mounted on the outside surface of the lid 123 (FIG. 20) through a rectangular hole 135 on the lid 123 as shown in FIG. 20. Another end of the linear actuator 124 is connected to a pinned support 125 fixed on the outside surface of the lid 123 (FIG. 20). Therefore, when the linear actuator 124 moves the sleeve 142 to connect the hub 141 with the synchronizer cone teeth on the damper 131, a desired locking mechanism would be achieved and the damper 131 is engaged in the assembly. In another way around, the linear actuator 124 may move the sleeve 142 to disconnect the hub 141 with the damper 131 so that the damper is disengaged in the assembly. As shown in FIG. 20, there is a neck mechanism in the halfway through the hole 135 to serve as a support for the connector 127 to work efficiently in moving the shift rod 134 in both ways.
(38) The door assembly 108 (FIG. 1) on the spherical shell is illustrated in FIG. 22a and FIG. 22b. The assembly 108 (FIG. 1) is capable to slide along a track bounded by a top track 145 and a bottom track 147 as shown in FIG. 22a. The top track 145 is mounted on an outside frames 107a (FIG. 22b) of the top half spherical shell 107 (FIG. 1) with two brackets 146 (FIG. 22b). The lower track 147 is mounted on an outside frames 106a (FIG. 22b) of the bottom spherical shell 106 (FIG. 1) with three brackets 146. There are two door frames in this assembly. One is the frame 107a-d (FIG. 22a) which is also an original frame of one bottom panel of the spherical shell 107 (FIG. 1) with the middle plate cut out as shown in FIG. 22a. Another frame is a sliding frame 156 which is holding a door panel 155 as shown in FIG. 22a. The sliding frame 156 and the door panel 155 are sliding together as one piece as shown in FIG. 22a. At least two sets of wheel assembly 149 (FIG. 23a) are mounted vertically at the top of the sliding frame 156 and at least two sets of wheel assembly 148 (only one set is shown in FIG. 23a) are mounted almost horizontally on the top of the sliding frame 156. Similarly, at least two sets of wheel assembly 151 (only one set is shown in FIG. 23b) are mounted vertically at the bottom of the sliding frame 156 and at least two sets of wheel assembly 150 (only one set is shown in FIG. 23b) are mounted horizontally on the bottom of the sliding frame 156 (FIG. 23b). At least four hinge assemblies 152 (FIG. 22a, FIG. 22b) are mounted on the four sides of the sliding frame 156, respectively to allow the door panel 155 to be opened and close easily as shown in FIG. 22a where the door panel 155 is opened and slides away with the sliding frame 156, and as shown in FIG. 22b where the door panel 155 is closed. There are four slots 157a, 157b, 157c (not shown), and 157d (not shown) on two vertical frame sides of the door panel 155 and there are four same size slots 158a (not shown), 158b (not shown), 158c, and 158d on the two vertical sides of the frame 107a-d as shown in FIG. 22a. Four flat door bolts 154 can be pushed into slot 158a, 158b, 158c, and 158d, respectively to lock the door panel 155 in place to form a perfect shell as shown in FIG. 22b. A door handle 153 (FIG. 22a and FIG. 22b) is located in the center of the door panel 155.
(39) The platform 119 is fixed to the ring beams horizontally inside of the spherical skeleton as shown in FIG. 10 and FIG. 11. The pilot cabin on top of the platform 119 as shown in FIG. 24 includes the pilot models 118, the dashboard 120, the screens 114, control columns 159, and other necessary apparatuses (not shown) such as batteries, air compressors, computers etc. The mass distributions of all the apparatuses on board the spherical vehicle needs to be carefully designed and arranged to meet a certain requirement described below.
(40) Due to space limitation of any motion simulators, translational motions (surge, sway, and heave) cannot be simulated 100%. For example heights and distances traveled by an aircraft or speeds of an aircraft in translational directions may not be able to be simulated. However, for a short period of time translational accelerations of a vehicle in surge, sway, and heave may be able to be simulated by moving the platform 103, the platform 102, and the piston 105 as shown in FIG. 1, respectively in order to apply desired inertial force effects on trainees on board the spherical vehicle 109. For rotational motions, there is no such space limitation in this invention which is able to simulate 100% rotational dynamics of vehicles including, but not limited to, aircrafts, automobiles, and ships. As we know it is the rotational motion characteristics that are the most crucial for the safety of these vehicles. To obtain valid results from this invention, the spherical vehicle must be designed and constructed in a special manner that will ensure that its rotational motions are identical with rotational motions that would be exhibited by a full scale vehicle. The spherical vehicle is not a geometrically scaled replica of the original vehicle, but a dynamically scaled model. For that purpose, a scaling factor needs to be determined first. The moments of inertias, the restoring coefficients, and the damping coefficients of the spherical vehicle and the driving moments acting on the spherical vehicle in this invention have to be at a same scale comparing with the counterparts (the original vehicle) to be simulated. More specifically, assume the rotational motions (, , ) of the original vehicle, for example an aircraft, are governed by the following equations in the principal inertia axes reference frame.
I.sub.x{umlaut over ()}+b.sub.1{dot over ()}+k.sub.1=(I.sub.yI.sub.z){dot over ()}{dot over ()}+M.sub.11(t),Math. 11
I.sub.y{umlaut over ()}+b.sub.2{dot over ()}+k.sub.2=(I.sub.zI.sub.x){dot over ()}{dot over ()}+M.sub.21(t),Math. 12
I.sub.z{umlaut over ()}+b.sub.3{dot over ()}+k.sub.3=(I.sub.yI.sub.y){dot over ()}{dot over ()}+M.sub.31(t),Math. 13
wherein, I.sub.x, I.sub.y, and I.sub.z are the moment of inertias of the original vehicle about the principal axes of X, Y and Z, respectively, b.sub.1, b.sub.2, and b.sub.3 are the damping coefficients for roll, pitch, and yaw, respectively, k.sub.1, k.sub.2 and k.sub.3 are the restoring coefficients for roll, pitch, and yaw, respectively, M.sub.11, M.sub.21, and M.sub.31 are the external moments along the roll, pitch, and yaw directions, respectively. In order to have dynamic equivalence between the full scale original vehicle and the spherical vehicle (or called subscale model) in this invention, let us multiply a constant scaling factor A to the above equations, we obtain.
I.sub.x{umlaut over ()}+b.sub.1{dot over ()}+k.sub.1=(I.sub.yI.sub.z){dot over ()}{dot over ()}+M.sub.11(t),Math. 14
I.sub.y{umlaut over ()}+b.sub.2{dot over ()}+k.sub.2=(I.sub.zI.sub.x){dot over ()}{dot over ()}+M.sub.21(t),Math. 15
I.sub.z{umlaut over ()}+b.sub.3{dot over ()}+k.sub.3=(I.sub.yI.sub.y){dot over ()}{dot over ()}+M.sub.31(t),Math. 16
(41) The spherical vehicle in this invention is designed to have moments of inertia about the principal inertia axes X, Y, and Z as I.sub.x, I.sub.y, and I.sub.z, respectively; the damping coefficients in roll, pitch, and yaw directions as b.sub.1, b.sub.2, and b.sub.3, respectively; the restoring coefficients in roll, pitch, and yaw directions as, k.sub.1, k.sub.2, and k.sub.3 respectively; and the moments acting in roll, pitch, and yaw directions as M.sub.11, M.sub.21, and M.sub.31, respectively. In summary, all these parameters are simply decreased in a same scale from that of the original values. The center of gravity of the spherical vehicle coincides with the geometric center of the spherical shell. Therefore the rotational motion dynamics of the full scale original vehicle would be identical with that of the spherical vehicle designed according to the above requirements because the governing equations Math. 11, Math. 12, and Math. 13 of the former are actually identical with the governing equations Math. 14, Math. 15, and Math. 16 of the latter. The scaling factor A could be ranging from very small, say 0.0001, for a very heavy vehicle to about 1 for a small vehicle or even larger than 1 for tinny vehicle depending on applications.
(42) For a ship application, the moments of inertias I.sub.x, I.sub.y, and I.sub.z should include the added mass effects and the yaw restoring coefficient k.sub.3 should be set to zero. Therefore the dynamics of the simulator would be conservative in terms of the nonlinear instability threshold value comparing with that of the original full scale ship.
(43) A plurality of ventilation ports, i.e. small holes (not shown) may be provided on a top portion of the top half spherical shell 107 to permit air circulation for occupants of the simulator if necessary.
(44) In another embodiment, a shell screen 160 may be mounted on the inside of the spherical skeleton 121 as shown in FIG. 25 to replace the screens 114 (FIG. 9) for showing the virtual reality view of simulations. In this case, the screen 114 may be replaced by transparent glasses.
(45) In yet another embodiment, the air bearing assemblies 115 (FIG. 9 and FIG. 14) may be replaced by omni-directional ball bearing assembly 170 as shown in FIG. 26a and FIG. 26b. In this case, on board air compressors are not needed.
(46) In an alternative embodiment, the platform 112 (FIG. 5) is mounted to a ground of a room that houses the simulator. This embodiment shows the version of the simulator that gives up three translational motions in exchange for a simpler design.
(47) It should be understood that the detailed description and specific examples, while indicating the preferred embodiment, are intended for purposes of illustration only and it should be understood that it may be embodied in a large variety of forms different from the one specifically shown and described without departing from the scope and spirit of the invention. This motion simulator in this invention can be as small or as large as is necessary for applications. It should be also understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprise a preferred form of putting the invention into effect, and the invention therefore claimed in any of its forms of modifications within the legitimate and valid scope of the appended claims.
