Abstract:
This invention provides a stabilizing system and method for two-wheeled vehicles that affords the rider no restriction on the full range of movements (banks, leans, etc.) common to bicycles, but that provides greater stability during turns and other maneuvers so that an unintentional bank or tilt (potentially causing a fall) is less likely, even at relatively slow speeds and startup. A rotating mass of predetermined mass-value and radial mass-distribution is provided coaxially with the front axle. The mass is supported on bearings so as to freewheel with respect to the rotation of the front wheel. As such it can be induced to spin significantly faster than the front wheel thereby generating a gyroscopic effect at the front wheel about the axle. This gyroscopic effect influences the steering of the wheel by the rider. Due to precession, the wheel tends to follow any excessive bank by the vehicle, ensuring that the rider can “steer-out-of” an unintended tilt or bank. Likewise, the gyroscopic effect limits the rider&#39;s ability to execute excessive steering, thereby preventing jackknife movements. The mass can be an electric-motor-driven flywheel within a shell housing that includes a battery, control system and drive motor. The drive motor engages a surface of the flywheel with a drive tire in a resilient manner to reduce potential damage to the motor.

Description:
RELATED APPLICATIONS 
     This application is a continuation-in-part of patent application. Ser. No. 11/967,491, filed Dec. 31, 2007 now U.S. Pat. No. 7,597,337, entitled SYSTEM AND METHOD FOR PROVIDING GYROSCOPIC STABILIZATION TO A TWO-WHEELED VEHICLE, the entire disclosure of which is herein incorporated by reference, which is a divisional of U.S. patent application Ser. No. 11/170,993, filed Jun. 30, 2005, entitled SYSTEM AND METHOD FOR PROVIDING GYROSCOPIC STABILIZATION TO A TWO-WHEELED VEHICLE, now U.S. Pat. No. 7,314,225, the entire disclosure of which is herein incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to stabilization systems for wheeled vehicles and training devices for new riders of such vehicles. 
     BACKGROUND OF THE INVENTION 
     Learning to ride a bicycle, or similar human-powered vehicle, is one of the more difficult physical challenges faced by young children (and some older ones). Children must develop awareness of what are, in essence, complex Newtonian principles of force-balance, gravity, torque, inertia and momentum. Only by continually adjusting weight and balance for the prevailing velocity and turn radius can one proficiently ride a bicycle for any distance. Starting a bicycle from a standing position is a particular challenge as the forward velocity needed to maintain balance has not yet been established. Likewise, turns are difficult for new riders as the weight and balance of the bicycle and rider shifts suddenly and may become difficult to control. It is not uncommon for new riders to jackknife the bicycle wheel, causing both bike and rider to tumble over. 
     The time-tested approach to preparing children to ride by exposing them to the basic dynamics of a bicycle is the use of training wheels. Briefly, training wheels are typically a pair small-diameter, hard rubber/plastic wheels attached by removable brackets to the rear axle. When properly installed, the training wheels each extend outwardly (in an axial direction) from a respective axle end several inches, and are mounted so that their lowest points are slightly above the contact point of the rear wheel with the ground. In this manner, the training wheels allow the rider to lean slightly in either direction with one training wheel, or the other, engaging the ground to prevent the bicycle for tipping further. 
     While training wheels are a common accessory on the bicycles of young riders, the traditional ritual of removing them, and allowing the rider to ride without these aids, is often fraught with peril and scraped knees. Basically, the rider must now experience a new range of dynamics that were unknown while the training wheels were still attached. Generally, training wheels are inadequate because they do not simulate real, unrestricted bicycle movement. They incorrectly teach riders to balance by relying on the training wheels rather than actually learning to balance through weight manipulation. Moreover, training wheels inhibit riders from banking as they turn, forcing them into bad habits. They rely on the training wheels, making the transition to autonomous riding extremely difficult. 
     It is highly desirable to provide a training device that can be used following, or as a substitute to, training wheels that allows new riders to experience the full range of dynamic forces associated with riding while still providing a degree of safety during startup turns and slow riding. In particular, a device that enables children to ride stably at the relatively slow speed of between 2.5 and 5 mph (common for most new riders), and potentially faster while still feeling the stability and behavior of a significantly faster moving bike is highly desirable. More generally, it is desirable to provide a device that enables all riders who desire or require added stability during startup and subsequent to startup to enjoy the benefits of such. 
     SUMMARY OF THE INVENTION 
     This invention overcomes the disadvantages of the prior art by providing a stabilizing system and method for wheeled vehicles (for example, motorized and human-powered bicycles, unicycles and/or tricycles, as well as specialized devices, such as hand-pedaled and reclining cycles) that affords the rider no restriction on the full range of movements (banks, leans, etc.) common to cycles, but that provides greater stability during turns and other maneuvers so that an unintentional bank or tilt (potentially leading to a fall) is less likely, even at relatively slow speeds and startup. A rotating mass of predetermined mass-value and radial mass-distribution is provided (in an illustrative embodiment) coaxially with the front axle. The mass is supported on bearings so as to freewheel with respect to the rotation of the front wheel. As such it can be induced to spin significantly faster than the front wheel thereby generating a gyroscopic effect at the front wheel about the axle. The rotating mass can define a flywheel structure in an illustrative embodiment. This gyroscopic effect induced on the wheel influences the steering of the wheel by the rider. Due to precession, the wheel tends to follow any excessive bank by the bicycle, ensuring that the rider can “steer-out-of” an unintentional tilt. Likewise, the gyroscopic effect limits the rider&#39;s ability to execute excessive steering, thereby preventing jackknife movements. The mass can be an electric-motor-driven flywheel within a shell housing that includes a battery, control system and drive motor. The drive motor includes a frictional drive tire that engages the surface of the flywheel under a movable spring pressure that accommodates any unevenness between the motor and the surface of the flywheel, so as to avoid possible damage to the motor. 
     In an illustrative embodiment, mass is mounted on bearings that are themselves mounted over the center hub of the cycle wheel. The cycle wheel is, in turn, mounted conventionally on a threaded axle that is attached to the front fork by opposing nuts. The mass of this embodiment is unpowered, and initially forced into rotation by action of a helper (adult) as the rider starts the ride. It can be urged to rotate using a variety of permanently attached and/or detachable mechanisms. One such mechanism employs a wrapped cord and a reel with a ratchet system that locks the reel in a cord-pulling direction and a spring that rewraps the cord in an opposite, cord-retracting direction. Alternatively, a removable rack and mass-mounted pinion can be used to rotate the mass. In another alternative embodiment, the mass can be rotated using a drill or other cordless/corded electrical device having an elastomeric attachment (or gear) that engages an appropriate drive hub on the mass. The attachment is inserted into contact with the hub for a small duration in which rotational motion is imparted to the drive hub from the electrical device. The device is then removed. The mass may rotate for a minute or more given proper bearings and balance. 
     In another embodiment, the mass can be permanently and selectively powered using, for example, a motor assembly that is coaxial with the wheel hub. A battery or other power source can be attached to the vehicle to provide continuous power. Such a powered implementation may be particularly suited for and adapted to disabled or older riders who require extra assistance. In addition, in alternate embodiments it is expressly contemplated that the rotating mass (powered or unpowered) can be provided non-coaxially within the structure of the steerable front wheel. Appropriate mountings and/or spaces can be provided to allow the non-coaxial mass to rotate appropriately free of interference from the moving wheel. 
     In an illustrative embodiment, there can be provided a front and/or steerable wheel (hub) assembly that is constructed and arranged to be fit onto a tire of a wheeled vehicle. The wheel assembly includes a flywheel assembly, rotatably mounted therein. The wheel assembly according to this embodiment encloses a rechargeable battery and a battery-powered electric motor that continuously drives a drive wheel in pressurable contact with the flywheel for initiating and maintaining rotation of the flywheel. The flywheel rotates freely about an axle of the wheel, on appropriate bearings that isolate its rotation from that of the wheel hub and tire to provide gyroscopic stabilization to the overall rotating wheel, and thus to the wheeled vehicle. 
     According to an illustrative embodiment, the wheel assembly includes a pair of outer shells (termed, for example first shell half and second shell half) that nest together to securely fit (clamshell-like) within each other to define a tire-engaging wheel rim. These shell halves together retain the flywheel assembly, electric motor, drive wheel, battery, motor control and associated circuitry within the interior defined by the halves of the wheel assembly. The pressurably contacting, motorized drive wheel initiates rotation of the flywheel by spinning the flywheel at one of a plurality of predetermined speeds. The motor control can step up and step down a series of incremental drive wheel speeds so as to approximately match the observed/predicted acceleration and deceleration rates (respectively) of the flywheel, based upon its inherent inertia. Alternately, the motor control can be adapted to sense the prevailing speed of the flywheel and apply incremental acceleration torque or deceleration braking as appropriate. Likewise, the control can be adapted, with appropriate charging circuitry to engage in regenerative braking when the motor is deactivated so as to recharge the battery assembly as the flywheel decelerates to rest. More particularly, the control is constructed and arranged to provide power from the electric motor to the battery when the flywheel is directed to spin down (i.e. the motor is deactivated via the push button or another command or state—such as a low-power state in the power supply/battery). Appropriate bearings and braces are provided in the wheel assembly to ensure the flywheel rotates freely therein and independent of the rotation of the assembly halves and the tire, which are separately mounted on bearings with respect to the common axle. The internal electrically driven wheel is spring biased into contact with the flywheel to initiate and maintain rotation of the flywheel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention description below refers to the accompanying drawings, of which: 
         FIG. 1  is a side view of a bicycle equipped with a stabilizing system according to an illustrative embodiment of this invention; 
         FIG. 2  is a fragmentary side view of a front wheel for the bicycle of  FIG. 1  including the stabilizing system having a rotating mass according to one embodiment; 
         FIG. 2A  is a fragmentary side view of a front wheel for the bicycle of  FIG. 1  including the stabilizing system having a rotating mass according to another embodiment; 
         FIG. 3  is a cross section of the wheel and rotating mass according to either  FIG. 2  or  FIG. 2A ; 
         FIG. 4  is a partially exposed perspective view of a cord-pull, recoil-type mechanism for initiating rotation of the mass according to an embodiment of this invention; 
         FIG. 5  is a fragmentary side view of an electrical device-driven mechanism for initiating rotation of the mass according to another embodiment of this invention; 
         FIG. 5A  is a fragmentary side view of the electrical device-driven mechanism of  FIG. 5  with an alternative drive hub design according to another embodiment of this invention; 
         FIG. 6  is a schematic diagram showing the various rotations and axes of interest on a bicycle in connection with this invention; 
         FIG. 7  is a side view of a bicycle and rider in a starting position employing the system and method of this invention; 
         FIG. 8  is a front view of the bicycle and rider of  FIG. 7  now in motion, and experiencing an imbalance; 
         FIG. 9  is a front view of the bicycle and rider of  FIG. 7  in which the imbalance of  FIG. 8  has induced an unintentional bank or tilt; 
         FIG. 10  is a front view of the bicycle and rider of  FIG. 7  in which the unintentional bank or tilt of  FIG. 9  is being compensated by precession of the rotating mass to cause the rider to gently steer into the bank; 
         FIG. 11  is an on-angle view of the bicycle and rider of  FIG. 7  showing the recovery from the imbalance due to the steering of  FIG. 10 ; 
         FIG. 12  is a graph comparing experimental data of upright travel (without rider) for the same bicycle with no rotating mass, a still mass and a properly rotating mass; 
         FIG. 13  is a graph comparing experimental data of travel path (with two different riders) for the same bicycle with no rotating mass, and a properly rotating mass; 
         FIG. 14  is a right perspective view of a wheel for a wheeled vehicle with a stabilizing system having a flywheel according to an illustrative embodiment of this invention, shown mounted on an exemplary steering fork of a vehicle; 
         FIG. 15  is a left perspective view of the wheel of  FIG. 14 , shown with the vehicle fork omitted; 
         FIG. 16  is a cross-sectional view further detailing the interior components of the wheel of to  FIG. 14 ; 
         FIG. 17  is an exploded perspective view detailing the components of the wheel of  FIG. 14 ; 
         FIG. 18  is a more-detailed exploded perspective view of the charging system and driving components of the wheel of  FIG. 14 ; 
         FIG. 19  is a partially exposed perspective view of the flywheel drive motor and motor mount shield of the wheel of  FIG. 14 ; 
         FIG. 20  is an exploded perspective view detailing the components as viewed from the back, of the wheel of  FIG. 14 ; 
         FIG. 21  is a flow chart showing a motor control procedure having various modes according to an illustrative embodiment of the invention; and 
         FIG. 22  is a fragmentary side view of an illustrative wheel assembly that is adaptable to larger-diameter tires according to an alternate embodiment of this invention. 
     
    
    
     DETAILED DESCRIPTION 
     A bicycle  100  having a stabilizing system according to an illustrative embodiment of this invention is shown in  FIG. 1 . This bicycle is exemplary of a certain size and style of human-powered two-wheeled vehicle that is particularly adapted for smaller children. The terms “bicycle” and “vehicle” as used herein are expressly intended to refer to any type of two-wheeled vehicle (including certain powered vehicles) that would benefit from the front-wheel gyroscopic stabilizing effect to be described herein. 
     The bicycle  100  includes a conventionally mounted rear wheel assembly  102 , driven by a chain  104  that is, in turn operatively connected to a pedal crank assembly  106 . The bicycle frame  108  is constructed from a set of joined tubular members that support a seat  110  above the frame  108  and is general alignment with the pedal crank assembly  106  so that a rider (see below) can reach and operate the pedals with his or her feet. 
     The front of the frame  108  includes a down-tube with internal bearings (not shown) that rotatably supports a front fork assembly  122  operatively connected to handlebars  124  of conventional design. On the lower end of the fork assembly  120 , a front wheel  130  assembly is rotatably mounted. In this embodiment, the front wheel assembly  130  includes an outer hub  132  upon which is mounted a tire (and inner tube not shown)  134 . The outer hub  132  is supported radially and axially with respect to an inner hub  136  by a set of spokes  138 . The inner hub is attached to the fork assembly&#39;s lower fork ends  140  as described further below. The attachment allows the inner hub  136  to rotate freely so that the bicycle can move in forward and reverse motion (forward motion being generally driven by the rear wheel assembly  102 ). Likewise, the handlebars rotate within a predetermined range (at least) about the steering axis (dashed line SA) to allow the front wheel to turn with respect to the frame. 
     Notably, the front wheel assembly  130  includes a rotating mass or “flywheel” assembly  160  mass according to an embodiment of this invention. With reference also to  FIG. 2 , the mass  160  is a circular disk  162  having a width (described below) that is nested within and passes freely between spokes  138  on each of opposing sides of the front wheel assembly  130 . The outside diameter DM of the mass disk  162  is smaller than the inner diameter DOH of the outer hub  132 . The difference between diameters is sufficient to allow the outside perimeter edge  210  of the disk  162  to clear the convergence of the spokes  138  that join along the narrowed outer hub from each of opposing sides of the wider inner hub  136 . In other words, the spokes generally define an equilateral triangle with the apex adjacent to the outer hub and the base at the inner hub. Since the apex region is quite narrow, the radial height of the disk should be short of the apex or any appreciable thickness in the disk will cause it to contact the spokes. However the disk diameter DM can be increased to nearly that (diameter DOH) of the inner hub by making the disk thin, particularly near its outer perimeter  210 . Conversely, as will be discussed further below, it is desirable to maintain the concentration of mass in the disk as far from the center (axis of disk rotation) to attain a high I value for the disk without rendering the disk overly heavy. 
     In order to accommodate a large-diameter disk, the outer hub  132  has been modified to locate the tire fill stem  220  so as to project from the side of the hub  132 , rather than the inner circumferential wall (as shown in phantom). Otherwise, the tire stem may contact the disk or simply be rendered difficult to access to fill the tire. A variety of tire stem placements and shape are contemplated and should be within the contemplation of those of ordinary skill whereby interference from the disk can be avoided. 
     The center of the disk  162  includes a “drive hub”  230  according to an illustrative embodiment. The shape, size and underlying function of the drive hub is highly variable. In this embodiment, the drive hub  230  includes a pull-cord unit that allows the pull-cord to be rapidly paid out by grasping and drawing upon a cord handle  232  that projects from the side of the front wheel assembly. Upon pulling, a ratchet assembly (described further below) engages the disk as causes the disk to spin. The drive hub ratchet works in conjunction with a recoil unit that withdraws the cord after release. The ratchet allows free movement without engaging the disk in the withdrawal direction. It is expressly contemplated that the drive hub can comprise a variety of mechanisms that initiate a high-rpm spin-up of the disk. 
       FIG. 2A  shows a wheel assembly  240  according to an alternate embodiment. As noted above, it is desirable the mass be concentrated along the outer perimeter of the wheel. Those of ordinary skill will recognize that the value for rotational moment of inertia (I, which equals mass m times the square of the radius, or I=mr 2 ) is optimized where more mass is concentrated at the outer perimeter of a rotating mass. Accordingly,  FIG. 20  shows an embodiment of a rotating mass  250  with spokes, rather than a solid structure. The mass is concentrated in the outer perimeter region  254 . In this manner overall weight of the disk (and hence the front of the bicycle) is reduced without substantially reducing I. In further embodiments, the mass can be concentrated in the perimeter of a solid disk by providing special weights (lead or steel billets for example) in an otherwise lightened solid disk constructed from, for example, aluminum or composite materials/polymers. Rotating masses need not define a continuous circular perimeter. In alternate embodiments, weight can be distributed in the mass at the ends of a plurality of separated arms, so long as the arms or perimeter structure is well balanced with respect to the central axis so as to avoid up-and-down wobble as the mass rotates within a gravitational field. For the purposes of this illustration, the first mass  162 , shown in  FIG. 2  can be constructed of steel with a thickness of approximately one inch (highly variable), a diameter DM of 14-15.5 inches (highly variable) and an evenly distributed total mass of approximately 13.5 pounds. The example of  FIG. 2A  the mass  250  is also constructed of steel with a thickness of about 1 inch. It also has an outer diameter DM of approximately 14-15.5 inches. In one experimental implementation, the total mass for this structure is approximately 12.3 pounds (a savings of more than a pound), and the I value is higher than the evenly distributed disk. By using heavier materials in combination with lighter composites the I-to-weight ratio for the mass can be optimized. In one example, the I value is in a general range of 210-240 pounds*in 2 , but a wider range of values for moment of inertia are expressly contemplated. 
       FIG. 3  shows a cross section of the central region of a wheel assembly and mass  162  according to the embodiment of  FIG. 2 . The wheel assembly is mounted on the bottom fork ends  140  by a pair of nuts  310 , which engage opposing ends of a threaded axle shaft  312 . The axle shaft  312  conventionally supports the inner hub  136  on bearings  320 . Note that the structure of the shaft  312  and inner hub  136  is highly variable. The main object is to provide a wheel that rotates relative to the front fork and a separate rotating mass that rotates freely with respect to both the wheel and the front fork so that the mass can rotate at a relatively high RPM so as to generate a gyroscopic effect even when the front wheel is barely moving or stationary. To accomplish this free rotation of the moving mass, the inner hub  136  has been divided into two pieces (or a plurality of sections)  324  and  326  with central break  330  therebetween, over which is placed a cylindrical sleeve  332  that forms a new joint between the separated inner hub sections  324 ,  326 . This joint maintains the radial alignment of the sections  324 ,  326  and forms a bearing surface for the mass. The sleeve  332  can be secured to the outside of the hub sections  324 ,  326  using (for example) welds, fasteners adhesives or a press fit. The outer surface of the sleeve  332  receives a bearing  340  that is pressed into the mass&#39; drive hub  230 . The drive hub can be constructed from any durable metal (aluminum alloy, for example) or polymer/composite material. In this manner, the drive hub  230  rotates freely on is bearing with respect to the sleeve  332 , and hence, the front wheel. The drive hub is secured to the radially outward portion  350  of the mass. This interconnection can be by press fit, fasteners, welds, adhesives or any other acceptable technique. Alternatively, the drive hub  230  and outer mass  350  can be formed unitarily from a single piece of formed, cast, molded, and/or machined material (with appropriate fillers, inserts and weights applied to the material where appropriate). 
     As shown clearly in  FIG. 3 , the drive hub includes a cylindrical extension  360  of reduced diameter with respect to the main drive hub portion  366  (that engages the outer mass  350 ). This extension  360  supports a wrapped cord  362  with a tail end  364  that exits the hub and engages the pull handle  232  shown in  FIG. 2  above. The firm withdrawal of the cord causes a rapid spin up of the drive hub. A well-balanced mass with a good bearing may spin at high RPM for several minutes. In this embodiment, a spin RPM of approximately 250-400 RPM is sufficient to provide stability as will be described below. 
     An optional spacer  370  is provided to at least one side of the sleeve  332 . This spacer assists in maintaining the drive hub axially centered on the sleeve. Alternate centering and fixing mechanisms are expressly contemplated. In addition, a conical or domed shield  376  is provided between the fork end  140  and spoke flange  370  as shown. While only one side is shown having a shield, this shield can be applied to both sides of the wheel assembly to protect the rider and others from the fast-rotating mass. The shield can be constructed from a durable polymer, such as polycarbonate. It can be transparent/translucent and can include various graphics and visual effects where appropriate. Likewise, the mass can be provided with graphical patterns that, in conjunction with the shield, may be used to create an entertaining effect when in motion. The shield  376  includes a port  380  through which the cord end  364  passes. This allows the user to pull the cord  364  while his or her hands are protected from contact with the mass. 
     With reference now to  FIG. 4 , a recoiling, cord-pull drive hub assembly  230  according to an illustrative embodiment of this invention is shown in further detail. It should be understood that the structure of this assembly is only exemplary. Those of ordinary skill should be familiar with this type of rotation-inducing mechanism as it is substantially similar to those found in the pull starters of small engines. The drive hub  230  includes the above-described larger-diameter main portion  366  and a smaller diameter projecting cylinder. This cylinder is actually an outer reel that rotates with respect to the main portion and a fixedly attached inner ratchet base  420 . The ratchet base includes a series of radial grooves  430  that selectively engage spring loaded pawls attached to the reel  410  when the cord end  364  is pulled outwardly (arrow  440 ). That is, the pawls  432  lock into the grooves  430  when the cord is pulled, causing the reel to rotate (curved arrow  444 ) and the main portion  366  to also rotate (curved arrow  446 ). However, the reel  410  includes a spring assembly  460  that is unwound by the pulling of the cord, and that rewinds to relieve tension, thereby drawing the cord back into a wound position (dashed arrow  450 ). The pawls  432  disengage for the ratchet bases  430  in this direction reverse to allow rewind to occur (dashed curved arrow  452 ). Likewise, the disengaged pawls allows the reel to be free from rotation while the mass spins at high speed (thus, no reverse dashed arrow on the main portion  366  is shown). 
     As noted above, the spin-up mechanism for the mass is widely variable. One alternate mechanism is shown in  FIG. 5 . Simply, the drive hub  510  includes an extension  512  from the main portion  514  that is frustoconical in shape. This allows firm engagement with a frustoconical tip  516  of an electrically driven device, such as the illustrated cordless drill  518 . The tip can be a hard rubber or other elastomer to firmly engage the extension  512 . By simply inserting the drill tip  516  through a hole in the shield (described above), the tip contacts the extension  512  and spins it once power is applied. In practice, the tip  516  can be provided as part of the kit a user receives with the bicycle and/or accessory wheel assembly of this invention. 
       FIG. 5A  shows a slightly modified drive hub  550  with a main portion  554 , in which the same frustoconical tip  516  (as  FIG. 5 ) drives a straight-cylindrical extension  552 . The corner  620  of the cylinder may assist in providing engagement between the tip and extension. A variety of tip shapes, extension shapes, materials and surface textures are expressly contemplated. 
     Having described the structure of an exemplary system for gyroscopically stabilizing a front wheel of a bicycle, the function of the system is now described in further detail. Referring to  FIG. 6 , the dynamic forces of interest are as follows: 
     Rotation of the wheels (curved arrows  610 ) translates into forward velocity along longitudinal axis  612  (when running with a straightened front wheel). Banking generally about the longitudinal axis (actually about wheel-to-ground contact points) is shown as curved arrow  620 . The front wheel steers (curved arrow  630 ) about the above-described steering axis SA. 
     The mass  160  rotates about the front wheel axis  650 , thereby generating a characteristic angular momentum L (where L=Iω, in which ω is the angular velocity of the rotating mass). The banking rotation represents a torque τ generally about the longitudinal axis  612 . Where angular momentum and torque cross, a precession is generated. This precession is the property whereby a gyroscope rotates at a predetermined magnitude in response to crossed forces. In this case the precession Ω P  is characterized by the equation:
 
τ=Ω P   ×L.  
 
     In other words, the equation governing precession is derived from the fact that torque equals the angular velocity of precession crossed with the angular momentum. Hence, a torque on a gyroscope (such as the torque from a child falling in an excessive or unintentional bank or tilt about the longitudinal axis) is transferred 90 degrees, and results in precession. For example, if the child were to tip to the right, the wheel would simply turn to the right. This allows the weight of the child to be re-centered over the front wheel. It is particularly desired that precession (Ω P ) be small in order so as to produce a relatively smooth recovery for the bicycle wheel. Since precession is inversely proportional to angular momentum a large I value, produces a relatively small precession for a given applied torque. 
     Reference is now made to the exemplary rider-training session of  FIGS. 7-11 . The process begins with the rider  710  seated atop the bicycle  100 , grasping the handlebars  124  in forward-steering position, with feet  712  prepared to begin pedaling. The helper places a grasping hand  720  on the pull-cord handle  232  and rapidly draws it (arrow  722 ) to spin the mass  160 . After spin-up, the rider  710  begins to pedal. 
     In  FIG. 8 , the rider  710  experiences and imbalance (arrow  810 ) that may lead to an unintentional/undesired bank or tilt. This bank occurs in  FIG. 9 , in which the bicycle leans (arrow  910 ) over, threatening to eject the rider  710 . 
     As shown in  FIG. 10 , due to the precession generated by the spinning mass  160 , the front wheel  130  turns smoothly (arrow  1010 ) in the direction of the unintentional bank, causing the handlebars  124  to be firmly urged to “steer-into” the bank. Thus the rider  710  experiences a turn that causes the bicycle  100  to begin to right itself (arrow  1020 ). Finally, in  FIG. 11 , the turn, induced by the imbalance and bank is complete and the rider  710  is riding vertically again in a new direction. The act of banking the bicycle has lead to a conventional turn, without jackknifing the bicycle or causing it to tip over, thus emulating a natural motion of banking and turning, even at relatively low speeds. This allows the young, slowly moving rider to learn the dynamics associated with faster riding, while maintaining a slower, safer speed. 
     To further prove the effectiveness of the stabilizing system of this invention a series of tests were performed with the approximate results shown in  FIG. 12 . A bicycle was launched, riderless (e.g. a “ghost” test) along a relatively flat path by hand at a relatively slow speed. Data bars for a non-moving mass ( 1210 ) show an upright time duration (before falling over) of approximately 1.2-2.2 seconds. Results are roughly similar for a bicycle with no mass installed ( 1230 ). Conversely, a bicycle with a mass moving at 200-400 RPM ( 1220 ) shows markedly increased upright time of approximately 2.3-6 seconds, with most times falling into the 4-5 second range (more than double the non-stabilized times). 
     Similarly,  FIG. 13  shows comparative graphs  1310  and  1320 ,  1330  and  1340  for two respective test subjects, both relatively inexperienced juvenile riders. The graphs show the length of path traveled versus diversion from a straight path (both in feet). In both cases the graph for the bicycle without spinning mass ( 1310  and  1330 ) displays a higher amplitude from a straight line than the graphs for the bicycle with properly spinning mass ( 1320  and  1340 ). 
     Reference is now made to  FIGS. 14-20 , detailing a wheel assembly  1400  according to another embodiment implementing a flywheel assembly and including an internal drive wheel and electric motor.  FIG. 14  is a right perspective view of a wheel assembly  1400 , constructed and arranged to be mounted on a conventional inner-tube tire  1410  having via a supporting rim  1420 . The wheel assembly  1400  is rotatably mounted on the lower end of a fork assembly  1440  of a wheeled vehicle (not shown), having a conventional frame for a wheeled vehicle extending from the vehicle fork assembly  1440 . The wheel assembly  1400  includes a front outer shell  1450  and an opposing back outer shell  1550  (shown in  FIG. 15 ). The tire  1410  can include conventional tire tread  1412  to provide fraction for the wheeled vehicle. As used herein the terms “front” and “back” should be taken as conventions only, rather than absolute indications of orientation or direction. They are herein chosen with reference to the field of view in  FIG. 14 . Likewise, the terms “left” and “right” with respect to the wheel assembly can be substituted and are used as conventions only. In general, the terms “first shell” and “second shell” can also be employed for each of the engaging shell halves that make up the overall assembled wheel assembly shell/enclosure. 
     The front outer shell  1450  includes a plurality of removably mounted cover plates  1432 ,  1434  and  1436 . Each of the cover plates are removably secured, or cemented to the front outer shell  1450 . Where removably secured, they can provide access to the components, features, and other aspects of the wheel assembly  1400  and flywheel assembly. The cover plates can be constructed from a transparent or translucent material and can be co-molded with the surrounding opaque material of the shell. Alternatively, the entire shell can be transparent or translucent and selectively painted or dyed to make some portions opaque. Transparent or translucent regions on the shell, as described below, are used to allow viewing of the spinning flywheel and/or other internal components for a dynamic, ornamental effect. As depicted the flywheel includes a number of circles ( 1750  in  FIG. 17 ), that can be representative of a polka dot graphic. A variety of other graphics, such as spiral can be employed on the visible surface of the flywheel. The cover plates can alternatively provide access to recessed compartments for containing items within the wheel, such as tools, or other appropriate items. The front outer shell  1450  and/or cover plates  1432 ,  1434  and  1436  can be formed of a polymer, stamped metal or other equivalent materials that can be translucent or transparent so as to reveal the flywheel assembly components and internal wheel assembly components. The front outer shell  1450  and cover plates  1432 ,  1434 ,  1436 , can thereby reveal, for example, a graphic displayed on the flywheel assembly, or can alternatively be color-tinted or otherwise decorated so as to provide a visually appealing wheel. (See polka dot graphic  1750  shown in  FIG. 17 , for example). 
       FIG. 15  shows a left side view of the wheel assembly  1400  having a back outer shell  1550 . The back outer shell  1550  includes cover plates  1532 ,  1534  and  1536  that are each removably secured to the rear outer shell, so that the internal components and other features of the wheel assembly are readily accessible. For example, the rear cover plate  1536 , which can be opaque, and constructed from a resilient material, removably covers an access port for the tire inner tube&#39;s air valve stem ( 1670  shown in  FIGS. 16 and 17 ) and the data (diagnostic) and battery charging plug ( 1632  in  FIGS. 16 and 17 ). 
     The back outer shell  1550  further includes a push button  1530  that is used in an illustrative embodiment to turn on and off the flywheel&#39;s electric drive motor and/or to alternate the speed of the motor. In alternate embodiments, the push button  1530  can be replaced with a remotely actuated button that is located, for example, on the handlebars or other frame location of the wheeled vehicle. In an embodiment, the button can signal the motor controller to select one of a plurality of spin speeds—for example by multiply pressing the button within a certain time interval. In this case, the remote button sends a wireless signal to the electric motor notifying that it should activate and commence spinning the internal drive wheel, and further selects the speed. 
     The front outer shell  1450  and rear outer shell  1550  are secured together via appropriate fasteners  1540 , such as screws that can be threadedly secured within the outer shells to secure the shells together. Accordingly, the wheel assembly  1400  is then provided as a solitary item that is placed within the rim  1420  of the tire  1410  to provide stabilization to the (steerable) wheel, also thereby stabilizing the wheeled vehicle itself. 
     Reference is now made to  FIG. 16 , a cross-sectional view detailing the internal components of the wheel assembly  1400  and the flywheel assembly  1650 . As shown, the front outer shell  1450  and back outer shell  1550  snap-fit together to secure the wheel assembly  1400  together. The front outer shell  1450  and the back outer shell  1550  each define one half of a conventional rim geometry with opposing circumferential flanges  1672 ,  1673  that are constructed and arranged to engage and capture the confronting bead of a conventional tire ( 1410 ) when the two shells are secured together by snap-fit so as to nest into a clamshell arrangement as shown. The flywheel assembly has at its center an inner hub  1652  that is supported within the wheel by an inner axle  1612  on bearings  1657  and  1659 . The various wheel assembly components and flywheel assembly components are secured axially within the front outer shell  1450  and rear outer shell  1550  by nuts  1614  and  1618  that also secure each outer shell within the axle and generally maintain the relative axial spacing between components in the clamshell. Also shown is fork lock  1616  to secure the axle to the fork ( 1440 ) of the wheeled vehicle (fork is not shown in  FIG. 16 ). 
     The rear outer shell  1550  is supported on the axle  1612  via bearings  1619  and  1630 . These bearings allow for free rotation of the axially aligned components including the outer shells and corresponding securing nuts with respect to the rotationally fixed inner axle  1612 . Similarly to the rear outer shell  1550 , the front outer shell  1450  includes bearings  1640  and  1642  that provide for free rotation of the axially aligned components. Also shown are nuts  1644  and  1648  that secure the components within the wheel assembly  1400 , and the fork lock  1646  that secures the wheel assembly  1400  to the fork of the wheeled vehicle. 
     As shown in  FIGS. 16 and 17 , there is provided an electric motor  1660  that rotates an internal drive wheel  1662  having a groove-seated driving tire (for example an O-ring  1664 ) that engages the surface of the flywheel  1650  at contact point  1651  located radially near the flywheel&#39;s outer perimeter edge. As shown in  FIG. 17 , there are provided compression (coil) springs  1620  and  1621  that bias the motor mount bracket  1655  so that the drive wheel  1662  is, in turn, biased against the flywheel  1650  to ensure the drive wheel  1662  causes the flywheel  1650  to rotate. As used herein the term “flywheel” should be taken broadly to define any type of unitary, multi-piece or other structure (broadly, a rotating mass) that rotates in a manner that generates a gyroscopic effect. The springs  1620  and  1621  are also provided to allow the contact between the flywheel  1650  and the internal driven wheel  1662  to constant, yet not a rigid point of contact, but rather a flexible/resilient contact. In this manner, there is a certain amount of play between the components, so as to prevent burnout of the motor from, for example, sudden motor acceleration/deceleration due to a hard bump, unexpected inconsistency in the flywheel geometry and/or surface shape, or other instances where the flywheel and internal driven wheel require slight adjustment and modification for movements. 
     In an illustrative embodiment, the electric motor  1660  operates at least at three rotational speeds, including low, medium, and high speeds. In alternate embodiments, the electric motor can be constructed and arranged to vary the degree of gyroscopic stability that results from the spinning of the flywheel by adjusting the rotational speed of the electric motor accordingly. In an illustrative embodiment, the low speed is at approximately 800 revolutions per minute, the medium speed is at approximately 1200 revolutions per minute and the high speed is approximately 2000 revolutions per minute. The exact number of revolutions per minute and speed of the electric motor is highly variable and these exemplary numbers are merely provided for illustrative purposes. The particular rotational speed of the electric motor is variable, so long as it provides the desired degree of rotation of the flywheel  1650  within the wheel assembly. More particularly, the electric motor can operate at a variety of input voltage ranges, and define a variety of maximum speed and/or torque ratings. 
     In an illustrative embodiment, the flywheel  1650  is comprised of steel, and as shown in  FIG. 20 , can have a structure such that the majority of the mass (and thus weight) of the flywheel is at the exterior portions of the flywheel  1650 , thereby further improving operation of the wheel assembly. This will be described with respect to  FIG. 20  below. 
     In an alternate embodiment, a regenerative system can be implemented. In general, once the internal drive wheel  1662  has caused the flywheel to accelerate to a desired rotational speed, it does not require as substantial continuing power input to maintain a predetermined rotational speed due to inherent inertia and the lowered friction provided by the bearings ( 1657 ,  1659 ). Accordingly, the motor may be pulsed on and off to conserve energy. Moreover, the motor control can be constructed and arranged to connect the batteries as a load on the motor after the system is shut off. In this manner, the motor can act as an electric brake, and recharge the batteries with the stored energy from the flywheel in a regenerative arrangement. Thus, the significant energy expended in accelerating the flywheel to a desired speed can be largely recovered during deceleration, and the less-significant energy needed to maintain a given rotational speed translates into a longer run time on a given battery charge. 
     A pair of batteries  1622  and  1623  ( 1623  not shown in  FIG. 16  cross-section) are located within the wheel in this embodiment. They provide sufficient power for the electric motor  1660  to spin-up and maintain rotation of the flywheel assembly for a predetermined time period. As shown in  FIG. 17 , the batteries are disposed between the motor mount bracket  1655  and the rear outer shell  1550  on opposing sides of the wheel assembly  1400  so as to provide the power to run the system. It is noted that the batteries are compact and appropriately sized so as to not interfere with the operation of the flywheel assembly in providing stabilization to the wheeled vehicle. The batteries can be constructed using Lithium Polymer, Nickel Metal Hydride, Nickel Cadmium, or any other acceptable battery technology. Alternatively, disposable batteries can be employed, with appropriate access ports in the structure to allow replacement thereof. In further embodiments, micro fuel cells or capacitors can be used to store electricity. The batteries are operatively connected to a control circuitry  1625  shown in  FIGS. 16 ,  17  and  18  that controls the speed of the electric motor  1660 . The control circuitry can be constructed on a single, application specific circuit chip, or from discrete electronic components, on a circuit board, using conventional circuit design techniques and components. In an embodiment is defines a microprocessor or microcontroller with a storage memory (onboard FLASH, for example) for storing operational firmware that can be reprogrammed when appropriate. Separate or integrated motor control circuitry can also be provided so as to vary the power applied to the drive motor. Such circuitry can be implemented in accordance with conventional electronic design principles. The motor can be implemented as a standard DC or AC motor (typically using rare earth magnets for enhanced torque and speed), or can be a motor including onboard feedback capabilities, such as an integral encoder, and/or a stepper arrangement. The control circuitry is illustratively adapted to operate the given type of motor employed herein. 
     The control circuitry  1625  controls the various speeds of the electric motor  1660 , as discussed hereinabove. Alternatively, the control circuitry can send (via a feedback loop) the appropriate signals to the electric motor to control the drive wheel based upon the speed at which the flywheel assembly is rotating so as to control power consumption. The various modes of the batteries and charging system of the wheel assembly are discussed in greater detail hereinbelow with reference to the motor control procedure and various modes of the system. 
     Also shown in  FIG. 16 , and more particularly in  FIGS. 18 and 20 , there is provided an optional lanyard  1631  prevents the back cover plate  1536  from becoming discarded with respect to the back outer shell  1550  when the cover plate is removed from the shell to access the charging and/or data plug  1632 . The charging and data plug  1632  is used for charging the batteries, and alternatively can be used for downloading to and/or uploading data from the control circuitry  1625 , for obtaining data relating to operation of the wheel assembly, providing updates to control circuitry software, and/or for controlling the flywheel assembly speed of rotation. In one exemplary embodiment, data regarding the stability of a rider can be uploaded to a portable device, such as a laptop computer, PDA or Apple iPod player. This data can allow an interested party (parent for example) to analyze and report on a riders learning progress. The data connector herein can be supplemented with or substituted for a wireless transceiver that employs, for example, the Bluetooth®, or similar communication standard. 
     Reference is now made to  FIGS. 18 and 19  which further detail the electric motor and motor mount assembly.  FIG. 18  further details the exploded front view of the flywheel assembly  1650  and internal components of the wheel assembly  1400 . As shown, the electric motor  1660  has an internal drive wheel  1662 , and corresponding drive tire (O-ring  1664 ), secured thereto by screws  1810  and respective washers  1820 . The electric motor  1660  includes a drive shaft  1840  onto which the internal drive wheel  1662  is placed to cause the drive wheel to rotate. The assembled electric motor and internal drive wheel configuration, disposed within the motor mount bracket  1655 , is shown in  FIG. 19 . Also shown in  FIG. 17 , the motor mount bracket  1655  is secured to the back outer shell  1550  by screws  1730 . These screws  1730  are shown in  FIG. 19  as securing the motor mount bracket  1655  to the rear outer shell  1550 . A variety of alternate fastening systems (rivets, welds, etc.) and/or alternate mounting arrangements can be employed in alternate embodiments. 
     Further shown in  FIG. 18  is the electrical connector securing bracket  1830  and plate member  1832  for securing the connector brace  1825  within the wheel assembly to provide a stable position for the electrical connector  1632  to allow access to charging the wheel assembly battery and optional data exchange for use in diagnostics, upload of control data, etc. 
       FIG. 19  shows the electric motor and motor mount bracket of the illustrative embodiment, secured together to show the drive wheel  1662  of the flywheel assembly. The internal drive wheel  1662  is driven by the electric motor  1660  to cause rotation of the flywheel  1650  (not shown in  FIG. 19 ). The control circuitry  1625  is shown in  FIG. 19  as well as the data and charging plug  1632 . The electrical hardware components of the control circuitry can include one or more microcontrollers or microprocessors that execute software instructions programmed into a local memory. These instructions enable the circuitry to control operation of the various devices contained within the circuitry and interconnected thereto. While not shown, the assembly can house additional sensors, lights and other electrically operated components. For example, LEDs or other lighting elements can be employed in combination with reflective surfaces to provide a lightings effect as the flywheel rotates. Likewise, the assembly can include sensors that measure tilt or steer (solid state gyros or accelerometers for example). These can be used by the controller to determine when to speed up or slow down gyro rotation, depending upon the historical and/or immediate severity of turns and tilts. Such sensors and the feedback they generate for the control circuitry can be used to aid new riders by automatically increasing the gyro effect based upon perceived severity of falls, etc. 
     Referring now to  FIG. 20 , the components of the wheel assembly and flywheel assembly are shown in exploded view from the back of the wheel assembly. As shown, in an illustrative embodiment the flywheel has a structure such that a greater portion of the flywheel mass is displaced proximate the outer edge  2010 , while the inner portion  2012  of the flywheel  1650  is narrower and has less mass. This allows the majority of the mass (weight) of the flywheel  1650  to be displaced at the outer edge  2010  of the flywheel  1650  to thereby improve the spinning induced by the flywheel and the overall stabilization induced on the wheeled vehicle. In alternate embodiments the flywheel can include spokes between the outer edge and the hub. Likewise, the flywheel body can be constructed from a lightweight material such as polymer or aluminum, and include individual inserts or a continuous ring of heavier material adjacent to the outer edge, such as lead. Furthermore, the flywheel can include one or more water/liquid-filled sections to enhance and distribute weight. 
     An assembly of foam dampers  2050  is shown. These dampers extend between the plate  1655  and associated pockets (not shown) in the inner surface of the shell  1550 . In an embodiment, the dampers are 15 mm×15 mm in cross section and 25 mm in length. The foam dampers in this embodiment are constructed of a pliable synthetic foam material (one of a variety of types and compounds) work in conjunction (in parallel) with the springs  1621  to absorb vibrations and mechanical noise within the moving motor mount assembly. This reduces wear on the motor&#39;s drive tire, which might otherwise occur in an undamped system as the tire bounces with respect to the flywheel surface. In this embodiment, each damper extends between the inner surface of the adjacent shell and the surface of the motor mount plate. Alternatively, a damping material or device can be operatively connected to another portion of the motor mount in a manner that damps the deflection of the spring assembly. For example, in an embodiment, foam dampers can be positioned as tubes that surround the springs and/or reside within the interior of each spring. The number of discrete dampers employed is also highly variable as is/are the geometric shape(s) thereof. 
     Also shown in  FIG. 20  is the push button  1530  that provides a straightforward mechanism for controlling the speed settings of the electric motor. The push button  1530  is operatively connected to the electric motor via control circuitry  1625  to select the speed of the internal drive wheel, as a low speed, medium speed or high speed. In alternate embodiments, the push button  1530  may be remotely located on the handlebars or other appropriate portion of the wheeled vehicle, or may alternatively be a type of system wherein the speed of the electrically driven internal wheel depends on the speed of the wheeled vehicle and flywheel assembly. In this manner, as the speed of the vehicle changes, requiring less gyroscopic speed to remain stable, the speed of the internal electrically driven wheel also changes respectively. In an embodiment, the speed of the motor can be regulated using a centrifugal switch that responds to the actual speed of the flywheel. 
       FIG. 21  details a flow chart showing an illustrative motor control procedure  2100  used by the control circuitry according to an illustrative embodiment of the invention. As shown in  FIG. 21 , the motor control procedure  2100  includes a plurality of optional “modes” or “states” of the system, shown as hexagon-shaped boxes of the procedure  2100 . The procedure  2100  has an initial “standing-by” state  2101  in which the system is in standing-by mode. If a button is pressed in step  2102  (for example the push button  1530  shown in  FIGS. 15 ,  17 ,  18  and  20 ) the procedure advances from step  2102 , to step  2103  where the speed level is read. Optionally, if the button is held for 10 seconds, at step  2104 , then the procedure advances to a hardware (HW) test state  2105 , in which a hardware test is performed, and the system then returns to the standing-by state  2101 . Note that the 10-second hold can be substituted the entry of a code via the button or data connector that initiates the hardware test in step  2105 . If the button is pressed two or more times, or the “read” time window expires, at step  2106 , the procedure advances to a “spinning up” mode at procedure step  2107 . Based upon the button-press, the motor is allowed to advance to the next speed level, if any. If the button is pressed at step  2108 , the procedure returns to the standing-by state at  2101 . If the spin-up time has expired at step  2109 , the motor continues to running mode at step  2110  at the set speed level. From this mode, if a button is pressed, it then returns to step  2108  and back to standing-by state  2101 . When the button is pressed and the speed level is zero, the spin-up step  2107  directs that power sufficient to provide the low speed level be applied to the motor. When the speed level is read as low, another button press triggers the spin-up step  2107  to provide more power to the motor, so as to attain a medium speed level. When the (user input) speed level at step  2103  is read as medium, after a button press, then the spin-up step applies a maximum power to the motor so as to achieve maximum speed. Likewise, when a maximum speed is read, after a button press, the spin-up step  2107  directs that power be removed from the motor. The circuit element for increasing or removing power can be a variable resistor arrangement or any acceptable power-varying component operatively connected to the processor carrying out the procedure  2100 . 
     While not shown, spin-up mode can include a number of stepped increases in power level that are timed approximately to the relative flywheel speed. That is, the power supplied to the motor in increased in small increments between absolute speed levels (low, medium, high) so that the motor is not overpowered, and dragging against the flywheel as it gradually accelerates, under the increased motor torque. 
     However, if a low battery is detected during the running mode at step  2110 , the procedure advances (via branch ‘A’) to step  2111  where the detection of a low battery is identified by the procedure  2100 . This advances the procedure to a motor-on, low-battery mode at step  2112 . The motor is still on, and the low battery is detected and a low battery state timeout is detected at step  2113 . This advances the procedure (via branch ‘D’) to the shutdown mode at step  2115 . Similarly, if the low battery is detected, and the button is pressed at step  2114 , the procedure also advances (via branch ‘D’) to the shutdown mode at step  2115 . If the low battery is detected and the charger is plugged in, yet the system is not powered at step  2116 , the procedure advances (via branch ‘C’) to the motor off, low battery mode at procedure step  2117 . This is the same result as the system detecting a low battery at step  2118  during the standing-by mode  2101  of motor control. 
     The motor control procedure  2100  in motor-off, low-battery mode at step  2117  is then either advanced to the shutdown mode (step  2115 ), by a button being pressed at step  2119 , or the state timeout from the low battery at step  2120 . Furthermore, a charger (not shown) can be plugged in, resulting in the motor-off, low-battery mode advancing to decision step  2123  where the procedure determines if the charger&#39;s A/C current end (or other current source) is plugged in and active. The procedure  2100  also advances to decision step  2123  if the charger is plugged in while the motor control is in a running mode at step  2110  (via branch ‘B’), or if the charger is plugged in while the motor control is in a standing by mode at step  2101 . If it is determined that the charger end is plugged in at decision step  2123 , then the procedure advances to step  2124  to determine if this is a proper type, and properly functioning (“good”), charger at decision step  2124 . 
     If the charger is not a good charger, then the procedure  2100  advances to step  2125  and an error is generated, and the system enters a charger-unplugged mode at step  2126 , in which case the motor control returns to a standing-by state at step  2101 . If the charger is found to be a good charger at decision step  2124 , then the motor control procedure is placed in charging mode at step  2127 . Conversely, if the charger is then unplugged, then the procedure  2100  branches to the charger unplugged mode at step  2126  which returns the motor control to a standing-by mode. If the battery is found to be fully charged, at step  2128 , the motor control procedure is in a fully charged mode at step  2129  until the charger is either unplugged, so as to enter unplugged mode at step  2126 , or until there is no longer fully charged power, and the procedure enters the charger in, no power mode at step  2130 . If the charger&#39;s A/C end is unplugged while the motor control procedure is in the charging mode at step  2127 , this similarly causes the motor control to enter the charger in, no power mode  2130  via step  2131  as the detection of the A/C end as being unplugged. 
     The motor control procedure in a charger-in, no-power mode at step  2130  then either is plugged in at step  2132 , which returns to the decision step  2124  to determine if it is a good charger. If a low battery is detected at step  2133 , the system enters a low battery motor off state at procedure mode step  2134 . If the charger becomes unplugged, the procedure advances to the charger unplugged mode at step  2126 , which again returns the motor control procedure to a standing by mode. 
     It should be clear that the above-described procedure  2100  for controlling operation of the drive motor is illustrative, and that a variety of alternate steps and/or functions can be provided. For example, the motor can be controlled by a relatively straightforward analog circuit that employs a variable resistor circuit to control speed, or that provides a basic on/off functionality with or without an incremental increase in power to the motor during spin-up. Moreover, as described generally above, the motor can be constructed and arranged to feed back power consumption and speed information that is used to more accurately regulate the application of additional power during spin-up, in accordance with conventional feedback control techniques. Likewise, as described above, the motor can be operatively connected with a regenerative circuit that converts rotation of the motor into recharging current that is fed to the batteries when the switch is shut off and the flywheel decelerates to a stop. Moreover, the initialization of the control procedure has been omitted. In general, this can include a number of hardware and software reset functions from an appropriate entry point. In addition, the system can check for such stored data as wheel size and firmware version to aid in providing proper operation. 
     Having now described an illustrative embodiment off the wheel and flywheel assembly of the present invention, and the motor control procedure for implementing the embodiments herein, alternate embodiments are now presented. Reference is made to  FIG. 22  showing an alternate embodiment of the present invention in which an adjustably sized wheel assembly  2200  is constructed and arranged to be placed on a larger sized tire  2210 . As shown, there is a larger sized rim  2220  having spokes  2230  and an inner rim  2240  into which the wheel assembly  2200  is placed. This provides for a variety of sizes and alternate types of wheel arrangements for various wheeled vehicles to provide stabilization thereto. As shown, the wheel includes an inner rim  2240  and outer rim  2220  having spokes  2230  therebetween to define an outer wheel adaptor such that the inner wheel assembly  2200  can be implemented on any size vehicle. The depicted alternate wheel assembly constructed and arranged to be adapted to fit any size tire, particularly a larger sized tire herein, is shown having a rim and spoke configuration, however any appropriate wheel can be implemented, including a single piece of material for the wheel adaptor to render the wheel assembly  2200  appropriate for all sizes of wheeled vehicles. In alternate embodiments, the spokes can be replaced with solid and/or ported annular spacers. Like attachment of the tire, the adaptor is mounted to the wheel assembly  2200  by securing the two opposing shell sides to its inner rim and securing the fasteners (screws) therebetween. 
     It should be clear that the embodiment of  FIGS. 14-21  (and the alternate embodiment  FIG. 22 ) provides an efficient (for example, the shell directly supports the tire), sturdy, safe (fingers cannot reach the flywheel) and novel arrangement for effecting the principles of this invention. It allows for mounting of a large variety of standard tires in a range of sizes and fitment to a wide range of conventional wheel mountings. The parameters herein can be modified to fit the wheel mountings of other types of vehicles (for example tricycles and unicycles in a manner). Such modifications should be clear to those of ordinary skill, and can entail changes to the wheel mount (fork, for example) and/or the wheel assembly itself. Likewise, while the drive mechanism in these embodiments is an electric motor, it is contemplated that the shell construction can house an alternate drive mechanism, including a spring-loaded clockwork mechanism, a compressed air motor and storage tank (pumped using a bicycle pump, compressor or the like) or any of the manually applied and/or operated mechanisms described with reference to the embodiments of  FIGS. 1-13 . This includes, but is not limited to, a hand-pulled rack, cord pull and elastomeric drill tip. The shell can be adapted to provide access for any of these manually applied driving elements in a manner clear to those of skill. Thus, the term “drive mechanism” should be taken broadly to include an onboard electric motor, an onboard motor powered by alternate energy sources, and/or an assembly that includes an internal drive hub that interacts with an externally applied driving element. 
     The foregoing has been a detailed description of illustrative embodiments of the invention. Various modifications and additions can be made without departing from the spirit and scope of this invention. Each of the various embodiments described above may be combined with other described embodiments in order to provide multiple features. Furthermore, while the foregoing describes a number of separate embodiments of the apparatus and method of the present invention, what has been described herein is merely illustrative of the application of the principles of the present invention. For example, a hub comprising a pair of clamshell halves that is assembled around the disk can be employed in an alternate embodiment, such a hub cab have outer surfaces that act both as a shield for the disk and the radial load-bearing member between the inner and outer hubs. Similarly, solid spokes with appropriate grooves for nesting the disk can be used. A variety of other improvements and modifications to the wheel, disk or drive hub can be implemented within the spirit and scope of this invention. Finally, while the exemplary embodiment described herein has been applied to a bicycle suitable for small children, it is expressly contemplated that this stabilizing system can be applied to the steerable front wheels of a variety of wheeled vehicles, both motorized and human powered. In alternate embodiments, it can be applied to adult-sized vehicles, such as mountain bikes, unicycles, reclining bicycles, hand-pedaled cycles, mopeds, motorcycles and scooters to provide further stability and/or act as a training tool. In addition, in alternate embodiments it is expressly contemplated that the rotating mass (powered or unpowered) can be provided non-coaxially within the structure of the steerable front wheel, or steerable rear wheel where applicable. Appropriate mountings and/or spaces can be provided to allow the non-coaxial mass to rotate appropriately free of interference from the moving wheel. The size of the flywheel or other rotating mass in both a motorized and non-motorized embodiment, as well as any surrounding enclosure or shell can be varied in diameter and radial placement of the majority of mass to accommodate the diameter and width of the desired tire. Moreover, while electric motors are described herein, motors operating on other power sources, such as micro-internal combustion and pressurized gas (compressed air, for example) engines, can also be employed to spin the flywheel. Additionally, while a drive tire engages a surface of the flywheel to drive it, a variety of fixed interconnections, such as gears, flexible shafts, centrifugal clutch assemblies, and the like, can be employed in alternate embodiments. Where electronic control is provided, the control can be implemented as hardware, software consisting of computer-readable program instructions, or a combination of hardware and software. Accordingly, this description is meant to be taken only by way of example, and not to otherwise limit the scope of this invention.