Abstract:
A two-wheel, self-balancing personal vehicle having independently movable foot placement sections. The foot placement sections have an associated wheel, sensor and motor and are independently self-balancing which gives the user independent control over the movement of each platform section by the magnitude and direction of tilt a user induces in a given platform section. Various embodiments are disclosed including those with a continuous housing, discrete platform sections and/or tapering platform sections.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of provisional application No. 61/597,777, filed Feb. 12, 2012, for a Two-Wheeled Self-Balancing Vehicle by the inventor herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to two-wheel, self-balancing vehicles and, more specifically, to such vehicles with two platform sections or areas that are independently movable with respect to one another and that thereby provide independent control and/or drive of the wheel associated with the given platform section/area. 
     BACKGROUND OF THE INVENTION 
     A first group of prior art two-wheel self-balancing vehicles is represented by a product known commonly as the “Segway.” This product is disclosed in U.S. Pat. No. 6,302,230, issued to Sramek et al (the &#39;230 patent). While a contribution in the field, the Segway and like devices are disadvantageous in that they are large, heavy and expensive, i.e., too heavy to be carried by a commuter or youth, too expensive for most to buy. Furthermore, turning is achieved through a handle bar structure that ascends from the platform upward toward the chest of a user. This tall steering structure is a trip hazard when a user makes an unplanned exit from the vehicle. 
     Another group of prior art two-wheel self-balancing vehicles has two platform sections, each associated with a given wheel, that tilt from side-to-side as a user leans left or right. The two platform sections move in a linked or “dependent” manner (for example, through a parallelogram frame, and not independently) and there is a single “vertical” axis for the platforms. When the axis is tilted directly forward or backward, both wheels drive at the same speed (as required for self-balancing). If a user leans to the side (tilts the “vertical” axis sideways), then the outside wheel is driven faster than the inside wheel to effect a turn toward the direction of the tilt. 
     These devices typically require a multi-component parallelogram structure to coordinate/link movement of the two platform sections and the wheels. Such componentry adds to the weight, bulk, complexity, and potential for mechanical failure of the device. Also, the turning radius is fairly large as one wheel is typically rotating around the other (moving in the same direction though at different speeds). 
     A need exists for a two-wheel self-balancing vehicle that provides independent wheel control, is light-weight and compact, is easy and safe to use, and that may be made in a cost-effective manner. A need also exits for a two-wheel self-balancing vehicle that is more maneuverable and more ergonomic (functioning more naturally with the bio-mechanics of a user&#39;s legs and body) than prior art devices. 
     Other prior art includes skateboards that have two platforms sections that are movable with respect to one another. Some have a shared shaft about which the two platform sections pivot, while others have a degree of flexibility in the platform. In both of these arrangements, the platform sections are arranged longitudinally, one primarily behind the other in the longitudinal line-of-direction of travel. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a two-wheel, self-balancing vehicle that overcomes the shortcomings of the prior art. 
     It is another object of the present invention to provide a two-wheel, self-balancing vehicle that has independently movable foot placement sections. 
     It is also an object of the present invention to provide such a two-wheel, self-balancing vehicle in which the independently movable foot placement sections are used by an operator to assert independent control over the driving of the wheel associated with the respective foot placement section. 
     These and related objects of the present invention are achieved by use of a two-wheel, self-balancing vehicle with independently movable foot placement sections as described herein. 
     The attainment of the foregoing and related advantages and features of the invention should be more readily apparent to those skilled in the art, after review of the following more detailed description of the invention taken together with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a two-wheel, self-balancing vehicle with independently movable platform sections in accordance with the present invention. 
         FIG. 2  is a block diagram of components within the vehicle of  FIG. 1 . 
         FIG. 3  is a bottom perspective view of another embodiment of a two-wheel, self-balancing vehicle with independently movable platform sections in accordance with the present invention. 
         FIGS. 4-5  are a top perspective view and a bottom perspective view of another embodiment of a two-wheel, self-balancing vehicle with independently movable platform sections in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , is a perspective view of a two-wheel, self-balancing vehicle  100  with independently movable platform sections in accordance with the present invention is shown. 
     Vehicle  100  may have a first and a second platform section  110 , 130 . Each platform section  110 , 130  may include a housing formed of a bottom housing member  111 , 131  and a top housing member  112 , 132 . The top housing members may have a foot placement section or area  113 , 133  formed integrally therewith or affixed thereon. The foot placement section is preferably of sufficient size to receive the foot of a user and may include a tread or the like for traction and/or comfort. 
     The housing may be formed of metal, sturdy plastic or other suitable material. The housing members may be molded and incorporate strengthening reinforcements, and be shaped to receive and “nest” the internal components (discussed below) of the vehicle. The bottom and top housing sections are formed complementarily so that after the internal components are installed, the top housing section is fitted onto the bottom housing section and secured with screws or other fasteners.  FIG. 1  illustrates holes  161 , through which the fasteners are inserted. 
     Each platform section includes a wheel  115 , 135 , and each wheel preferably has an axle  116 , 136  and motorized hub assembly  117 , 137  (shown in  FIG. 2 ). Motorized hub assemblies are known in the art. 
     Referring to  FIG. 2 , a block diagram of components within vehicle  100  in accordance with the invention is shown. The dot-dash line represents a rough outline of the housing members. Each platform section preferably includes a position sensor  120 , 140 , which may be a gyroscopic sensor, for independent measurement of the position of the respective platform section. The sensors are preferably mounted on circuit boards  121 , 141  that may be attached to the interior of the respective bottom housings. Sensed position information from sensor  120 , 140  is used to drive the corresponding motor  117 , 137  and wheel  115 , 135 . The control logic for translating position data to motor drive signals may be centralized or split between the two platform sections. For example, control logic  150  may be electrically connected to sensors  120 , 140  and to drive motors  117 , 137 , electrical conduits connecting through the connecting shaft  170  between sensor  140 , control logic  150 , and drive motor  137 . 
     Alternatively, a separate processor/control logic  151  may be provided in the second platform section  130 . Logic  151 , in this case, would be is connect directly to sensor  140  and drive motor  137  and generate drive signals to motor  137  (and wheel  135 ) based data from sensor  140 . 
     Communication between these components is primarily in the direction of data from the sensor and drive signals to the motor. However, communication in the other direction may include start signals (ie, to the sensor), status signals (ie, from the motor indicating an unsafe condition (e.g., excessive rpm), or a motor/drive failure or irregularity). This information, in addition to battery information, etc., could be communicated back to a user via lights or another interface, or communicated wirelessly (e.g., blue-tooth) from the vehicle to a hand-held device such as a mobile phone. In addition, if the platform sections have separate and independent control logic  150 , 151 , these processing units may still share information with one another, such as status, safe operation information, etc. 
     The two platform sections  110 , 130  are movably coupled to one another.  FIG. 2  illustrates a shaft  170  about which they may rotate (or pivot with respect to one another). Brackets  164  and flange brackets  165  may secure the shaft to the platform sections, with the flange brackets preferably configured to prevent or reduce the entry of dirt or moisture within the housings. Shaft  170  may be hollow in part and thereby allowing for the passage of conduits therethrough. Pivoting or rotating shaft arrangements are known in the art, and others may be used without deviating from the present invention as long as the foot placement sections may move independently. 
     Since the platform sections may rotate or pivot with respect to one another, the left section  110 , for example, may tilt forward while the right section tilts backward. This would cause the wheels to be driven in opposite directions, causing a user to spin-in-place or “pirouette” much like a figure skater. Alternatively, the platform wheels could be tilted in the same direction, but one platform more than the other. This would cause the wheel associated with the more steeply tilted platform to drive faster, in turn causing the vehicle to turn. The sharpness of the turn could be readily adjusted by the user based on the relative tilt of the platform sections. 
     This leg movement to control turning is a very ergonomic and natural movement, akin to skiing and other gliding/sliding activities. 
     The rotating shaft  170  may also include a bias mechanism integral with the flange bracket  165  or otherwise configured to return the platform section to an even level in the absence of displacement from a riders weight. 
     Each platform section  110 , 130  may also include a platform or “shut-off” sensor  119 , 139  that detects when a user is standing of the platform. When a user falls off, the absence of the rider is sensed and the control logic in response stops driving the wheels such that the vehicle comes to a stop (and does not carry on rider less). In the absence of such a shut-off sensor, the vehicle would still stop rather soon as the wheels will be driven to a self-balancing position for their respective sections bringing the device to rest. 
     Referring to  FIG. 3 , a bottom perspective view of another embodiment of a two-wheel, self-balancing vehicle  200  with independently movable platform sections in accordance with the present invention is shown. Vehicle  200  may include first and second platform section  210 , 230  that are formed of bottom  211 , 231  and top  212 , 232  housing sections, similar to those in vehicle  100  above. 
     Each platform section includes a wheel  215 , 235  which is respectively driven by a motorized hub  217 , 237  and an associated position sensor  220 , 240 . Control logic  250  receives the sensed position information and drives the associated wheel toward self-balancing. As discussed above, the control logic  250  may be independent, provided in each platform section, or centralized, provided in one section. Regardless, the driving of each wheel is based on the position sensed by the sensor associated with that wheel. 
     A pivoting shaft or other arrangement may be used to movably/rotatably join the two platform sections. 
     Referring to  FIGS. 4-5 , a top perspective view and a bottom perspective view of another embodiment of a two-wheel, self-balancing vehicle with independently movable platform sections  300  in accordance with the present invention is shown. Vehicle  300  is similar to the other vehicles herein, yet instead of a pivoting or rotating connection between platform sections, the frame or housing is made of a sturdy yet sufficiently flexible material that the two foot placement sections are effectively first and second platform sections that move independently with respect to each other for independent control of wheels  315 , 335 . 
     Vehicle  300  may include a bottom  311  and a top  312  housing sections. These may be made of a flexible steel or durable flexible plastic or the like. The two sections are preferably configured to receive the internal components. They are preferably complementary in shape and may be secured by fasteners from below. The top housing may include or have attached to it a rubber coating or surface or the like in the foot placement areas  313 , 333  to increase traction and/or comfort with the foot of a user. 
     The internal components may include position sensors for both sections  320 , 340 , hub motors  317 , 337 , and control logic  350  for independently driving wheels  315 , 335  toward a self-balancing position based on position information sensor by their respective sensors  320 , 340 . These components may be the same or similar to those discussed above for vehicles  100  and  200  ( FIGS. 1-3 ). 
     While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention and the limits of the appended claims.