Patent Publication Number: US-8528854-B2

Title: Self-righting frame and aeronautical vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This Non-Provisional Utility application claims the benefit of co-pending Chinese Patent Application Serial No. 201010235257.7, filed on Jul. 23, 2010, which is incorporated herein in its entirety. 
     FIELD OF THE INVENTION 
     The present disclosure generally relates to apparatuses and methods for a frame and the construction of a frame that rights itself to a single stable orientation. More particularly, the present disclosure relates to an ovate frame that rights itself to an upright orientation regardless of the frame&#39;s initial orientation when placed on a surface. 
     BACKGROUND OF THE INVENTION 
     Remote controlled (RC) model airplanes have been a favorite of hobbyists for many years. Initially, in the early years of RC aircraft popularity, the radio controls were relatively expensive and required a larger model aircraft to carry the weight of a battery, receiver and the various servos to provide the remote controllability for the model aircraft. These aircraft were typically custom built of lightweight materials, such as balsa wood, by the hobbyist. Consequently, these RC models represented a significant investment of the hobbyist&#39;s time, effort, experience, and money. Further, because of this investment, the hobbyist needed a high degree of expertise in flying the model aircraft to conduct safe operations and prevent crashes. In the event of a crash, most models would incur significant structural damage requiring extensive repairs or even total rebuilding of the model. For these reasons, participation in this hobby was self-restricting to the few who could make the required investments of time and money. 
     As innovations in the electronics industry resulted in smaller and less inexpensive electronics, the cost and size of radio control units were also reduced allowing more hobbyists to be able to afford these items. Further, these advances also result in reductions in weight of the battery, receiver and servos, which benefits could then be realized in smaller and lighter model airframes. This meant that the building of the airframes could become simpler and no longer requiring the degree of modeling expertise previously required. Simplicity of construction and durability of the airframes were further enhanced with the advent of more modern materials, such as synthetic plastics, foams, and composites, such that the airframes could withstand crashes with minimal or even no damage. 
     These RC models were still based upon the restraints of airplane aerodynamics meaning they still needed a runway for takeoffs and landings. While the length of the required runways (even if only a relatively short grassy strip) vary according to the size of the RC model, the requirement often relegated the flying of these models to designated areas other than a typical back yard. Model helicopters, like the full scale real life aircraft they are based upon, do not require runways and can be operated from small isolated areas. However, a helicopter with a single main rotor requires a tail rotor, whether full scale or model, also requires a tail rotor to counter the rotational in flight moment or torque of the main rotor. Flying a helicopter having a main rotor and a tail rotor requires a level of expertise that is significantly greater than required for a fixed wing aircraft, and therefore limits the number of hobbyists that can enjoy this activity. 
     The complexity of remotely flying a model helicopter has at least been partially solved by small prefabricated models that are battery operated and employ two main counter-rotating rotors. The counter-rotation of the two rotors results in equal and counteracting moments or torques applied to the vehicle and therefore eliminating one of the complexities of piloting a helicopter-like vertical take-off and landing model. These models typically have another limiting characteristic in that the form factor of the structure and the necessary placement of the rotors above the vehicle structure result in a tendency for the vehicle to be prone to tipping on one or the other side when landing. In the event of this occurring, the vehicle must be righted in order for further operations and thus requires the operator or other individual to walk to the remote location of the vehicle and right it so that the operator can again command the vehicle to take off. 
     Therefore, a self-righting structural frame and corresponding vertical take-off vehicle design is needed to permit remote operation of a helicopter-like RC model without the need to walk to a landing site to right the vehicle in the event the previous landing results in a vehicle orientation other than upright. 
     SUMMARY OF THE INVENTION 
     The present disclosure is generally directed to an aeronautical vehicle incorporating a self-righting frame assembly wherein the self-righting frame assembly includes at least two vertically oriented frames defining a central void and having a central vertical axis. At least one horizontally oriented frame is desired and would be affixed to the vertical frames extending about an inner periphery of the vertical frames for maintaining the vertical frames at a fixed spatial relationship. The at least one horizontally oriented frame provides structural support, allowing a reduction in structural rigidity of the vertical frames. It is understood the at least one horizontally oriented frame can be omitted where the vertical frames are sufficiently designed to be structurally sound independent thereof. A weighted mass is mounted within the frame assembly and positioned proximate to a bottom of the frame assembly along the central vertical axis for the purpose of positioning the center of gravity of the frame assembly proximate to the bottom of the frame assembly. At a top of the vertical axis, it is desirous to include a protrusion extending above the vertical frames for providing an initial instability to begin a self-righting process when said frame assembly is inverted. It is understood that the protrusion may be eliminated if the same region on the self-righting frame assembly is design to minimize any supporting surface area to provide maximum instability when placed in an inverted orientation. When the frame assembly is inverted and resting on a horizontal surface, the frame assembly contacts the horizontal surface at the protrusion and at a point on at least one of the vertical frames. The protrusion extends from the top of the vertical axis and above the vertical frames a distance such that the central axis is sufficiently angulated from vertical to horizontally displace the center of gravity beyond the point of contact of the vertical frame and thereby producing a righting moment to return the frame assembly to an upright equilibrium position. 
     In another aspect, an aeronautical vehicle that rights itself from an inverted state to an upright state has a self-righting frame assembly including a protrusion extending upwardly from a central vertical axis. The protrusion provides an initial instability to begin a self-righting process when the aeronautical vehicle is inverted on a surface. At least one rotor is rotatably mounted in a central void of the self-righting frame assembly and oriented to provide a lifting force. A power supply is mounted in the central void of the self-righting frame assembly and operationally connected to the at least one rotor for rotatably powering the rotor. An electronics assembly is also mounted in the central void of the self-righting frame for receiving remote control commands and is communicatively interconnected to the power supply for remotely controlling the aeronautical vehicle to take off, to fly, and to land on a surface. 
     In still another aspect, an aeronautical vehicle that rights itself from an inverted state to an upright state has a self-righting frame assembly including at least two vertically oriented intersecting elliptical frames. The frames define a central void and each frame has a vertical minor axis and a horizontal major axis wherein the frames intersect at their respective vertical minor axes. Two horizontally oriented frames are affixed to the vertical frames and extend about an inner periphery of the vertical frames for maintaining the vertical frames at a fixed spatial relationship. A weighted mass is positioned within the frame assembly along the central vertical axis and is affixed proximate to a bottom of the frame assembly for the purpose of positioning a center of gravity of the aeronautical vehicle proximate to a bottom of the frame assembly. At a top of the vertical axis a protrusion, at least a portion of which has a spherical shape, extends above the vertical frames for providing an initial instability to begin a self-righting process when the aeronautical vehicle is inverted on a surface. When the aeronautical vehicle is inverted and resting on a horizontal surface, the frame assembly contacts the horizontal surface at the protrusion and at a point on at least one of the vertical frames. The protrusion extends from the top of the vertical axis and above the vertical frames a distance such that the central axis is sufficiently angulated from vertical to horizontally displace the center of gravity beyond the point of contact of the vertical frame thereby producing a righting moment to return said frame assembly to an upright equilibrium position. At least two rotors are rotatably mounted in the void of the self-righting frame assembly. The two rotors are co-axial along the central axis and counter-rotating one with respect to the other. The rotors are oriented to provide a lifting force, each rotor being substantially coplanar to one of the horizontal frames. A power supply is mounted in the weighted mass and operationally connected to the rotors for rotatably powering the rotors. An electronics assembly is also mounted in the weighted mass for receiving remote control commands and is communicatively interconnected to the power supply for remotely controlling the aeronautical vehicle to take off, to fly, and to land on a surface. 
     In another aspect, the self-righting aeronautical vehicle can be designed for manned or unmanned applications. The self-righting aeronautical vehicle can be of any reasonable size suited for the target application. The self-righting aeronautical vehicle can be provided in a large scale for transporting one or more persons, cargo, or smaller for applications such as a radio controlled toy. 
     In another aspect, the vertical and horizontal propulsion devices can be of any known by those skilled in the art. This can include rotary devices, jet propulsion, rocket propulsion, and the like. 
     In another aspect, the frame can be utilized for any application desiring a self-righting structure. This can include any general vehicle, a construction device, a rolling support, a toy, and the like. 
     These and other features, aspects, and advantages of the invention will be further understood and appreciated by those skilled in the art by reference to the following written specification, claims and appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described, by way of example, with reference to the accompanying drawings, where like numerals denote like elements and in which: 
         FIG. 1  presents a perspective view of an aeronautical vehicle having a self-righting frame according to the present invention; 
         FIG. 2  presents a 45 degree oblique side elevation view of the aeronautical vehicle; 
         FIG. 3  presents a side elevation view of the aeronautical vehicle; 
         FIG. 4  presents a top plan view of the aeronautical vehicle; 
         FIG. 5  presents a bottom plan view of the aeronautical vehicle; 
         FIG. 6  presents an cross-sectional view of the aeronautical vehicle shown in  FIG. 4 , taken along the line  6 - 6  of  FIG. 4 ; 
         FIG. 7  presents a perspective view of a user remotely operating the aeronautical vehicle; 
         FIG. 8  presents an elevation view of the aeronautical vehicle resting on a surface in an inverted orientation; 
         FIG. 9  presents an elevation view of the aeronautical vehicle resting on the surface and beginning the process of self-righting itself; 
         FIG. 10  presents an elevation view of the aeronautical vehicle resting on the surface and continuing the process of self-righting itself; 
         FIG. 11  presents an elevation view of the aeronautical vehicle resting on the surface and approximately one-half self-righted; 
         FIG. 12  presents an elevation view of the aeronautical vehicle resting on the surface and over one-half self-righted; 
         FIG. 13  presents an elevation view of the aeronautical vehicle resting on the surface and almost completely self-righted; 
         FIG. 14  presents an opposite elevation view of the aeronautical vehicle as shown in  FIG. 13  and almost completely self-righted; 
         FIG. 15  presents an elevation view of the aeronautical vehicle at completion of the self-righting process; and 
         FIG. 16  presents a view of a representative remote control unit for use by a user for remotely controlling the aeronautical vehicle. 
     
    
    
     Like reference numerals refer to like parts throughout the various views of the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to make or use the embodiments of the disclosure and are not intended to limit the scope of the disclosure, which is defined by the claims. For purposes of description herein, the terms “upper”, “lower”, “left”, “rear”, “right”, “front”, “vertical”, “horizontal”, and derivatives thereof shall relate to the invention as oriented in  FIG. 1 . Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
     Turning to the drawings,  FIG. 1  shows a remotely controlled aeronautical vehicle  120  employing a self-righting structural frame  140 , which is one of the preferred embodiments of the present invention and illustrates its various components. 
     Referring now to  FIGS. 1-6 , aeronautical vehicle  120  and more particularly self-righting frame assembly  140  includes at least two substantially identical vertically oriented frames  142  arranged in an intersecting manner such that the axis of their intersection also defines a central vertical axis  150  of self-righting frame assembly  140 . Frames  142  are further oriented one with respect to the other to substantially define equal angles about an outer periphery of self-righting frame  140 . 
     Each frame  142  defines an outer edge  144  having a continuous outer curve about a periphery of frame  142 . Frames  142  may have a circular shaped outer curve  144 , but in a most preferred embodiment, frames  142  have an elliptical shape wherein the major axis (represented by dimension “a”  186  of  FIG. 2 ) is the horizontal axis of frames  142  and wherein the minor axis (represented by dimension “b”  187  of  FIG. 2 ) is the vertical axis of frames  142  (i.e., dimension “a”  186  is greater than dimension “b”  187 ). Frames  142  also have an inner edge  148  which, if frames  142  were rotated about axis  150 , define a central void  146 . A bottom  124  of frames  142  and thus of frame assembly  140  is flattened instead of carrying the elliptical form through to central axis  150 . The flattened bottom area  124  of frames  142  contributes to a stable upright equilibrium of frame assembly  140 . 
     At least one horizontal frame  152  extends about an inner periphery of central void  146 . In a most preferred embodiment, two horizontal frames  152  extend about the inner periphery of void  146  and are vertically spaced one from the other. Frames  152  are affixed to each frame  142  substantially at inner edges  148  of frames  142  and maintain the plurality of frames  142  at a desired fixed spatial relationship one to the other, i.e. defining substantially equal angles one frame  142  with respect to an adjacent frame  142 . 
     A weighted mass  154  is positioned with frame assembly  140  and affixed thereto in a stationary manner. As illustrated, weighted mass  154  is held captive in a stationary manner proximate to a bottom  124  of the plurality of frames  142  along central vertical axis  150 . While one manner of holding weighted mass  154  captive is accomplished by frames  142  conforming to an outer periphery of weighted mass  154 , as illustrated, other manners of retaining weighted mass  154  are contemplated such as using mechanical fasteners, bonding agents such as glue or epoxy, or by other known methods of captive retention known in the industry. The preferred position and weight of weighted mass  152  is selected to place the combined center of gravity of aeronautical vehicle  120  as close to the bottom  124  of vehicle  120  as possible and at a preferably within the form factor of weighted mass  154 . 
     A protrusion  158  is affixed to a top portion  122  of frame assembly  140 . Protrusion  158  extends upwardly and exteriorly from outer edge  144  of frames  142  and in a preferred embodiment an upmost part of protrusion  158  has a spherical portion  160 . Those practiced in the art will readily recognize by the disclosures herein that protrusion  158  can be any shape that provides for a single point of contact  194  ( FIG. 9 ) at protrusion  158  with a surface  102  ( FIG. 9 ) when frame assembly  140  is in a substantially inverted orientation on surface  102  ( FIGS. 8-9 ). 
     As illustrated in  FIGS. 1-6  and particularly  FIGS. 2 and 6 , self-righting frame  140  is easily adapted for use in a Vertical Take-Off and Landing (VTOL) aeronautical vehicle  120 , here illustrated as a remotely controlled flyable model. Aeronautical vehicle  120  includes self-righting frame assembly  140  and further includes a maneuvering and lift mechanism  170  for providing aeronautical lift and maneuvering of aeronautical vehicle  120  during flight operations. Maneuvering and lift mechanism  170  includes a power supply  176  and remote control electronics  178  for powering and controlling aeronautical vehicle in flight operations. Power supply  176  as illustrated are contemplated to comprise an electrical battery and electric motor, however other power configurations utilized for flyable model aeronautical vehicles are also contemplated. Remote control electronics  178  are capable of receiving remote control radio frequency (RF) signals and translating those signals into control inputs to the power supply  176  for providing directional and velocity controls to aeronautical vehicle  120 . Power supply  176  and electronics  178  are further contemplated to be substantially the same as or adapted from like mechanisms utilized for remotely controlled helicopters, but may also be of a unique design for aeronautical vehicle  120  and known to those practiced in the art. 
     Power supply  176  and electronics  178  are preferably housed within and contribute to the function of weighted mass  154  as previously described. A rotating mast  174  is connected to power supply  176  extending upwardly from weighted mass  154  and is coincident with central axis  150 . At least one aerodynamic rotor  172  is affixed to mast  174  and when rotated at a sufficient speed functions as a rotating airfoil to provide lift to raise aeronautical vehicle  120  into the air for flying operations. However, as with all aeronautical vehicles employing a rotating aerodynamic rotor to provide lift, aeronautical vehicle  120  also requires an anti-torque mechanism to maintain the rotational stability of self-righting frame assembly  140 . A preferred embodiment of aeronautical vehicle  120  includes a second aerodynamic rotor  173  that is also rotatably powered by power supply  176  wherein each rotor  172 ,  173  is substantially co-planar with a respective horizontal frame  152  as illustrated in  FIGS. 2-3 . However, rotor  173  is geared to rotate in an opposite direction from rotor  172  and thus countering the torque produced by rotor  172 . Such co-axial counter-rotating rotor systems are well known in VTOL design. Other anti-torque systems known in the art and contemplated herein include a single main rotor and a second mechanism such as a smaller rotor at right angles to the main rotor and proximate to a periphery of frame  140  or dual laterally separated counter-rotating rotors. 
     Maneuvering and lift mechanism  170  can also include a stabilization mechanism comprising a stabilizer bar  180  having weights  181  at opposite ends thereof also rotatably affixed to mast  174  to rotate in conjunction with rotors  172 ,  173 . Stabilizer bar  180  and weights  181  during rotation stay relatively stable in the plane of rotation and thus contribute to the flight stability of aeronautical vehicle  120 . Bar  180  and weights  191  are of a configuration known in the helicopter design art. 
     Referring now to  FIGS. 7 and 16 , flight operations of the model VTOL aeronautical vehicle  120  are shown wherein a user  104  utilizes a remote hand controller  106  to send control signals to aeronautical vehicle  120  to take off from and fly above surface  102 . Remote hand controller  106 , as further shown in  FIG. 16 , includes a case  108  formed to include handles  110  for grasping by user  104 . Case  108  also houses the electronic circuitry (not shown) to generate and transmit the RF control signals for broadcast to aeronautical vehicle  120  to permit the remote controlled flight of vehicle  120 . Controller  106  includes a power cord  114  for recharging batteries and various controls such as on-off switch  111  and joy sticks  112 ,  113  to generate the command signals for vertical and lateral translations of vehicle  120  thereby allowing user  104  to control vehicle  120  to take-off, perform flight maneuvers, and land. 
     During flight operations of a remotely controlled helicopter, one of the major problems occurs when the vehicle tips or lands in other than an upright orientation. In those instances, the user must travel to the location of the vehicle and re-orient the vehicle and then resume operations. The self-righting frame  140  of VTOL aeronautical vehicle  120  causes vehicle  120  to, in the event of other than an upright landing, re-orient itself without the aid of the user. 
     A worst case scenario of aeronautical vehicle  120  landing in an inverted orientation and its self-righting sequence is illustrated in  FIGS. 8-15  and described herein. In  FIG. 8 , vehicle  120  has hypothetically landed in a worst case inverted orientation on surface  102  wherein aeronautical vehicle  120  is hypothetically resting on surface  102  at a single point of contact of spherical portion  160  of protrusion  158 . Because of the spherical geometry of portion  160  or other geometry employed such that in an inverted orientation, there is only single point contact such as with a portion  160  being conical, protrusion  158  imparts an initial instability to frame assembly  140 . Further, the initial instability is enhanced by weighted mass  154  positioning center of gravity  156  opposite most distant from the single point of contact of portion  160  of protrusion  158 . The initial instability initiates a moment force “M”  189  to begin rotating vehicle  120  about the point of contact of portion  160 . 
     Turning now to  FIG. 9 , vehicle  120  begins to seek a state of equilibrium from the initial state of instability described with respect to  FIG. 8 . Those practiced in the mechanical arts will readily recognize that such a state of equilibrium would occur when frame assembly contacts surface  102  at three points defining a contact plane with the weight vector  188  of vehicle  120  vertically projecting within the triangle on surface  102  defined by the three points of contact of frame assembly  140 . As illustrated in  FIG. 9 , protrusion  158  with spherical portion  160  extends above the elliptical profile of frames  142  a dimensional distance of “Z”  193 . As vehicle  120  tips to one side from protrusion  158  contact point  194 , outer edge  144  of frames  142  contact surface  102  at frame contact points  195 . The dimension “Z”  193  extension of protrusion  158  and portion  160  above frames  142  results in central axis  150  being angulated from vertical by angle “A”  190 . 
     As illustrated, adjacent frames  142  each have a contact point  195  (in  FIG. 9 , a second frame  142  is hidden behind the illustrated frame  142 ) such that, as illustrated, a line interconnecting points  195  is orthogonal to the drawing page and forms one leg of a contact triangle defining a contact plane for vehicle  120 . The line connecting points  195  is a distance “Y”  192  from contact point  194  of protrusion  158 . If the lateral or horizontal displacement of weight vector  188  is such that vector  188  operates through the contact triangle defined by contact point  194  of protrusion  158  and the two contact points  195  of adjacent frames  142 , an equilibrium state for vehicle  120  is found and it will remain in that state until disturbed into an unstable state. However, as illustrated in  FIG. 9 , height dimension “Z” is sufficiently large to create angle “A” such that weighted mass  154  and vehicle center of gravity  156  have been horizontally displaced from vertical by a distance “X”  191 . Height dimension “Z” is selected to insure that dimension “X”  191  is greater than dimension “Y”  192 . 
     Turning now to  FIG. 10 , the vehicle of  FIG. 9  is viewed as from the left side of  FIG. 9  wherein weighted mass  154  being on the far side of the contact points  195  of  FIG. 9  and creating righting moment “M”  189 , vehicle  120  follows righting moment “M”  189  and continues its rotation to an upright position. Likewise, as illustrated in  FIG. 11 , weighted mass  154  approaches the ninety degree position of rotation from vertical. Those practiced in the art will readily recognize that an outer periphery of horizontal frame  152  in a preferred embodiment will not engage surface  102  as vehicle  120  or frame  140  rotates across surface  102 . In this manner, the self-righting motion caused by moment “M”  189  will remain continuous and uninterrupted. 
     Referring now to  FIGS. 12-14 , vehicle  120  and frame  140  continue to rotate toward an upright position with weighted mass  154  consistently acting beyond the shifting points of contact of adjacent vertical frames  142 . In  FIG. 12 , weighted mass  154  rotates downwardly from its ninety degree position and in  FIGS. 13 and 14 , weighted mass  154  approaches a position proximate to surface  102  wherein vehicle  120  is almost upright,  FIG. 14  being a one hundred eighty degree opposing view of  FIG. 13 . 
     In  FIG. 15 , vehicle  120  has achieved a stable upright equilibrium state wherein weighted mass  154  is most proximate to surface  102  and wherein flattened bottom  124  defines a resting plane on surface  102  to maintain upright stability of vehicle  120 . Once aeronautical vehicle  120  has self-righted itself, vehicle  120  is once again ready to resume flight operations without requiring user  104  to walk or travel to the location of vehicle  120  to right it prior to resuming flight. 
     Those skilled in the art will recognize the design options for the quantity of vertical frames  142 . Additionally, the same can be considered for the number of horizontal frames  152 . The propulsion system can utilize a single rotor, a pair of counter-rotating rotors located along a common axis, multiple rotors located along either a common axis or separate axis, a jet pack, a rocket propulsion system, and the like. 
     Those skilled in the art will recognize the potential applications of the self-righting frame assembly for use in such items as a general vehicle, a construction device, a rolling support, a toy, a paperweight, and the like. 
     The self-righting structural frame  140  provides a structure allowing a body having a width that is greater than a height to naturally self-orient to a desired righted position. As the weight distribution increases towards the base of the self-righting structural frame  140 , the more the frame  140  can be lowered and broadened without impacting the self-righting properties. 
     Since many modifications, variations, and changes in detail can be made to the described preferred embodiments of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalence.