Patent Publication Number: US-2022212752-A1

Title: Electric bicycle

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 62/842,241, filed on May 2, 2019. The entire teachings of the above application are incorporated herein by reference. 
    
    
     BACKGROUND 
     Bicycles comprising front and rear wheels mounted to a frame with handlebars, seat and drive pedals are well known. Also known are bicycles driven by electric motors. 
     SUMMARY 
     An electric bicycle comprises a midframe and a pedal driven generator supported by the midframe with pedals extending to opposite sides of the midframe. Each of front and rear wheels comprises a rotating tire. Each wheel is mounted to the midframe with a swivel mount, the wheels being configured to swivel from in-line positions to collapsed positions on opposite sides of the midframe. A handlebar is mounted through a handlebar support to the front wheel and a seat is mounted through a seat support over the rear wheel. A first wheel motor in a first one of the front and rear wheels comprises a stator fixed to the midframe and a rotor that drives the tire of the first wheel. A current source is charged by the pedal driven generator, and electronics control charging of the current source from the pedal driven generator and delivery of power to the wheel motor from the current source. 
     One or each of the front and rear wheels supports a wheel motor. Each wheel motor may comprise a stator fixed to the midframe and a rotor that drives the tire of the wheel. Each wheel motor may also be configured to operate as a generator. The pedal driven generator may also be operable as a motor. 
     The bicycle may be collapsed to the extent that the wheels are positioned to roll in parallel directions. To that end with simple joints, each swivel mount may comprise a single axis joint that swivels about a tilted swivel axis. 
     Each stator may comprise opposed rings forming a wheel rim, and the rotor may be positioned between the stator rings and support the tire. The center region of the wheel within the stator may be open. The pedal driven generator may comprise a rotor ring to which the pedals are mounted and a stator ring fixed to the midframe. The pedals may pivot to close into an open center region of the generator. 
     The seat and handlebar may be configured to be repositioned to enable a rider to pedal the bicycle as a unicycle when the wheels are in the collapsed position. In that configuration, the bicycle may be used for exercise in a fixed location or limited area. It may even be configured to stand stationary as the pedals are driven. 
     As an alternative to the collapsed position, the bicycle may be configurable to swivel the front and rear wheels to the same side of the midframe, perpendicular to the midframe. In that configuration the bicycle may be configured as a walker with the handlebar and seat removed, the handlebar support and seat support serving as handles. Alternatively, a first portion of the midframe to which the front and rear wheels are mounted may be upright and another portion of the midframe pivoted from the first portion to serve as a seat. As another alternative, after the wheels are swiveled to the same side of the midframe, the wheels are rotated to position the midframe close to and along the ground to support a load. The wheels may be swiveled further to meet each other away from the ground. 
     The handlebar support and the seat support may each be mounted to swivel about a transverse axis, and the handlebar and seat may each rotate about the respective support. 
     The midframe may comprise a curved tube coupled at opposite ends to the stator of the front wheel, one end adjacent to the handlebar support. The swivel mount may include a swivel joint in the tube displaced from the handlebar support. The midframe may further comprise a curved tube coupled at opposite ends to the stator of the rear wheel, one end adjacent to the seat support. The swivel mount of the rear wheel may comprise a swivel joint in the tube displaced from the seat support. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing will be apparent from the following more particular description of example embodiments, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments. 
         FIG. 1  is a side view of an electric power bicycle embodying the present invention; 
         FIG. 2  is a perspective view of the bicycle of  FIG. 1 ; 
         FIG. 3  is a side view of an alternative embodiment of the invention including an additional midframe segment; 
         FIG. 4  is a side view of an alternative embodiment with a relocated seat support; 
         FIG. 5  is a side view of an embodiment incorporating the features of  FIGS. 3 and 4 ; 
         FIG. 6  is a front, end view of the embodiment of  FIG. 1 ; 
         FIG. 7  is a top view of the embodiment bicycle of  FIG. 1 ; 
         FIG. 8  through  FIG. 11  are top views of the bicycle of  FIG. 1  being collapsed, with the seat relocated below the rear swivel joint; 
         FIG. 12  is a side view of the collapsed bicycle with the handlebar and seat relocated for carrying; 
         FIG. 13  is an end view of the compact configuration of  FIG. 12 ; 
         FIGS. 14 and 15  are side views like  FIG. 12  but with the handlebar position at two different locations; 
         FIG. 16  is a perspective view of the collapsed bicycle with the handlebar and the seat repositioned for unicycle operation; 
         FIG. 17  is a top view of the configuration of the  FIG. 16 ; 
         FIG. 18  is a front perspective view of the configuration of  FIG. 16 ; 
         FIG. 19  is a rear end view of the configuration of  FIG. 16 ; 
         FIG. 20  is a perspective view of an alternative configuration of the bicycle of  FIG. 3  configured as a walker; 
         FIG. 21  is an end view of the walker configuration of  FIG. 20 ; 
         FIG. 22  is a side view of the walker configuration of  FIG. 20 ; 
         FIG. 23  is a top view of the walker configuration of  FIG. 20 ; 
         FIG. 24  is a perspective view of the walker configuration of  FIG. 20  with the midframe addition tilted forward; 
         FIG. 25  is an end view of the configuration of  FIG. 24  with the handlebar attached; 
         FIG. 26  is a perspective view of the configuration of the  FIG. 25 ; 
         FIG. 27  is a perspective view of an alternative configuration configured as a chariot; 
         FIG. 28  is a top view of the chariot configuration of  FIG. 27 ; 
         FIG. 29  is an end view of the chariot configuration of  FIG. 27 ; 
         FIG. 30  is a side view of the chariot configuration of  FIG. 27 ; 
         FIG. 31  is a perspective view of the chariot configuration of  FIG. 27  with a package mounted on the chariot; 
         FIG. 32  is an end perspective view of an alternative compact configuration for carrying packages; 
         FIG. 33  is a top view of the configuration of  FIG. 32 ; 
         FIG. 34  is an end view of the configuration of  FIG. 32 ; 
         FIG. 35  is a top perspective view of the configuration of  FIG. 32 ; 
         FIG. 36  is a top perspective view of the configuration of  FIG. 32  with a package mounted for transport; 
         FIG. 37  is a side perspective view of the configuration of  FIG. 36 ; 
         FIG. 38  is a perspective view of the configuration of  FIG. 32  modified to carry a user; 
         FIG. 39  is a side view of the configuration of  FIG. 38 ; 
         FIG. 40  is a rear end view of the configuration of  FIG. 38 ; 
         FIG. 41  is a top view of the configuration of  FIG. 38 ; 
         FIG. 42  is an alternative configuration like that of  FIG. 24  but modified for seating on the midframe segment; 
         FIG. 43  is a perspective view of the configuration of  FIG. 42  with the addition of seating net; 
         FIG. 44  is an end view of the configuration of  FIG. 42 ; 
         FIG. 45  is a side view of the configuration of  FIG. 42 ; 
         FIG. 46  is a top view of the configuration of  FIG. 42 ; 
         FIG. 47  is an electrical block diagram of the electronic control used in each embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     A description of example embodiments follows. 
       FIGS. 1 and 2  provide a side view and perspective view of an electrically powered bicycle. The bicycle includes a front wheel  102 , a rear wheel  104  and a midframe  106 . The midframe  106  includes a generator-motor  108 . The generator-motor  108  includes a rigid stator  110 , that forms part of the midframe structure. A rotor  112  is mounted by ring bearings to the stator to rotate within the stator. The rotor  112  supports pedals  114  and  116  to enable a user to rotate the rotor. 
     The midframe  106  also includes a front tubular structure  118  that may be curved to follow the curve of the wheel  102 . Similarly, the curved tubular structure  120  follows the curve of the rear wheel  104  and completes the midframe. The tubular structures  118  and  120  carry batteries or capacitors to be charged by the generator motor  108  and the two drive wheels  102  and  104  as described below. The frame tubes  118  and  120  also carry electronics for controlling charging and discharging of the battery or capacitors and to control speed and inertial force applied to the wheels and generator as described below. 
     A handlebar  122  is mounted to the top end of the frame tube  118  through a telescoping support  124 . The support  124  is mounted to the tube  118  through a pivot joint  154  that allows the handlebar to be tilted forward or backward about a swivel axis  202  illustrated in  FIG. 2 . 
     A seat  126  is mounted to the upper end of the rear frame tube  120  through a telescoping support  128 . The support  128  is mounted to the tube  120  through a swivel joint  156  that swivels about an axis  204  illustrated in  FIG. 2 . The seat  126  is mounted to the support  128  at a pivot joint that allows the seat to be pivoted about an axis  206  illustrated in  FIG. 2 . 
     The front wheel comprises a circular motor  130 ,  138  that drives the tire  140 . The motor includes a left and right stator structures  130  that are fixed to the frame tube  118  at the top end by U-shaped bracket  132  and at the bottom end by U-shaped bracket  134 . The stator elements are joined at the front of the bike by a U-shaped bracket  136 . A rotor  138  mounted by ring bearings within the stator elements is driven by electric current through the stator elements. The tire  140  is mounted to the rotor  138  to be driven with the rotor. 
     A similar wheel structure is provided at the rear of the bicycle. Stator elements  142  are joined by U-shaped brackets  144 ,  146  and  148  and mounted to the ends of the rear frame tube  120  at the brackets  144  and  146 . A rotor  150  is mounted through ring bearings within the stator elements and drives the rear tire  152 . Thus, it can be seen that each of the wheels comprises a rigid stator structure that forms a rim of the wheel and that is rigidly coupled to the midframe  106 . A rotor and tire rotate relative to each set of stator elements to drive the bicycle in forward or reverse motion. 
     To steer, the front wheel  102  can be turned relative to the midframe  106  about a vertical axis  158 . To that end, a top segment  160  of the frame tube  118  is joined to the main body of the frame tube  118  through a swivel joint  162 . The stator elements  130  are mounted to the lower end of the frame tube  118  through another swivel joint  164 . By rotating the handlebar  122 , the front wheel is turned in a manner like that of a conventional bicycle. In addition, the swivel action enables reconfiguration of the bicycle as described in detail below. 
     Turning of the rear wheel is also enabled, not for turning during operation of the bicycle or for the configuration of  FIG. 1 , but for reconfiguring the bicycle as described below. To that end, an upper end segment  166  of the frame tube  120  swivels about a vertical axis  172  at a swivel joint  168 . Also, the stator elements  142  are mounted to the lower end of the frame tube  120  at a swivel joint  170 . 
     The rotors  138  and  150  can be back driven to become a generator. There are many motor-generator candidate designs including Halbach array, gearless, brushless DC motor-generators and Lorentz force (homopolar or Faraday) motor-generator designs. The design of such motor-generators is well known. 
     The rotors  138 ,  150  and stators  137 ,  142  are connected via slender ring bearings (e.g., incorporating balls, rollers or needles). In another embodiment, these ring bearings could incorporate very low sliding friction materials such as graphene. 
     Each motor-generator can be independently computer controlled and, when acting as a motor, generates torque which propels the bike using energy stored in the energy storage units located in the tubular frame. When riding down hills, the motor-generators now act as generators and convert the kinetic energy of the bike and rider (and any goods adding to the payload) to stored electrical energy (in the energy storage elements inside the tubular frames). 
     The rate at which energy is extracted (i.e., power) from the motor-generators acting as generators determines the angular velocity dependent torque (i.e., viscosity) as seen by the internal computer control system hidden in the tubular frame. For example, during a down-hill ride, if the power extracted from the generators is high, then the bike will slow down (via viscous drag exerted by the motor-generators as they harvest energy). Indeed during aggressive braking a maximum power is extracted from the generators (i.e., from both wheels). 
     Braking at a low speed may use another strategy in which the front and/or rear wheels act as motors to generate torques opposing forward motion (i.e., energy is consumed from the energy storage elements). 
     The energy storage elements hidden in the tubular frame might be batteries of some type (e.g., lithium ion batteries) having a suitably high power and high energy density, or in another embodiment might be capacitors (having a suitably high power and high energy density). 
     The smaller mid generator-motor  110 ,  112  located between the front and rear wheels can be of a similar design to those used in the front and rear wheels. 
     Torques generated by the bike rider are transmitted via the pedals  114 ,  116  to the rotor  112  of the middle generator-motor unit. The electrical energy generated is then stored in either or both types of energy storage units. The rate of energy (power) extracted from the torques generated by the bike rider is computer controlled. This enables the rider to control (via the computers, power electronics and all three motor-generators) the ratio between power exerted by the rider on the pedals and the power delivered to the road surface by the front and rear motor-generators acting as motors. In this way a very wide range of ratios between the human rider input power and the power exerted by the bike on the road may be selected. In this way the system acts like a traditional bicycle gear system but without the need for physical gears. Indeed, the system enables a continuous range of “gear ratios” to be generated. 
     The rider may control speed and pedal resistance through sensor grips  208  and  210  on the handlebar. For example, the user may exert a rotary torque on the right grip to speed up (rotation torque forward) and slow down (rotation torque backward) or exert a rotary torque on the left grip to change the drag force. 
     Note the absence or need for any chain connecting the pedals to the rear wheels and the absence or need for any physical gears. 
     It is to be understood that the three motor-generators (front, mid and rear) are controlled with power amplifiers which both deliver power from the energy storage units and conversely can harvest kinetic energy from the motor-generators (front, rear), as driven by the road surface, and deliver that energy to the energy storage units. 
     A solenoid hidden in the frame tube  118  at the swivel joint  162 , and possibly another at swivel joint  164 , can be activated to lock the front wheel into a variety of positions when the bike is reconfigured into non-traditional form as described below. A similar solenoid is associated with the rear wheel at joint  168 , and possibly at joint  170 . This solenoid locks the rear wheel into the forward pointing orientation (as shown) when the bike is in the traditional configuration or into other positions described below. 
     Multi-axis force sensors embedded in the handlebar support  124  and the rear seat support, respectively, are used in both traditional (as shown) and nontraditional (as shown in subsequent figures) bike configurations to control the bike by a rider or to allow a human to walk beside the bike and via gentle forces exerted on either the handlebar support of the seat support to guide the bike. The same sensors are used in the nontraditional bike configurations (show below) to issue commands to the bike (such as to set its speed or direction). 
       FIG. 3  shows another embodiment substantially the same as that of  FIGS. 1 and 2  except that it additionally includes an additional frame  302  as part of the midframe. Curved tubes  304  and  306  are positioned adjacent to frame tubes  118  and  120 , lower tube  308  is positioned adjacent to the generator-motor  108 , and an upper tube  310  bridges the tubes  304  and  306 . The additional frame segment  302  increases rigidity of the frame and provides additional space for power storage batteries and capacitors and for electronics. The frame  302  also provides additional function in other configurations of the bicycle described below. 
       FIG. 4  illustrates another embodiment that is substantially the same as that of  FIGS. 1 and 2  with an alternative mounting of the seat. Here, the telescoping seat support  402  is mounted at a lower end of an upper segment  406  of the rear frame tube  120  at a swivel joint  404 .  FIG. 4  also shows the handlebar  122  and the handlebar support  124  swiveled forward relative to what is shown in  FIG. 1 . 
       FIG. 5  illustrates a bicycle identical to that of  FIG. 4  with the addition of the additional frame segment  302  previously shown in  FIG. 3 . 
       FIG. 6  is a front view of the bicycle of  FIGS. 1 and 2 ; and  FIG. 7  is a top view of the bicycle of  FIGS. 1 and 2 . 
       FIGS. 8-11  are top views showing the bicycle being folded to reconfigure it into a collapsed configuration. In order to reconfigure the bike in the front and rear, solenoids at swivel joints  162  and  168  are temporarily activated to unlock the bike such that the front and rear wheels are free to swivel about their respective swivel axes  158  and  172 . Once this is done, the bike rider may swivel the front and rear wheels around their respective swivel axes  158 ,  172  by almost 180 degrees with the result that the front and rear wheels are adjacent to each other on either side of the midframe  106  as shown in  FIG. 11 . 
     In  FIGS. 8-11 , the seat  126  is seen to be relocated and clamped on the frame tube  120  at a position below the swivel joint  168 . Accordingly, it does not rotate with the rear wheel  104 . If the seat were retained at the upper end of segment  166  of the frame tube  120  as shown in  FIG. 1 , it would rotate with the wheel. In  FIG. 11 , the seat would be shown further to the left and pointing in the reverse direction. 
     In  FIG. 8 , the front and rear wheels  102 ,  104  are swiveled about respective swivel axes  158  and  172  toward opposite sides of the midframe  106 . In  FIG. 9 , the wheels are swiveled further, and in  FIG. 10 , the wheels are swiveled almost to their full extent alongside the midframe  106 .  FIG. 11  shows the fully collapsed configuration in a top view. In  FIG. 11 , the pedals extend through the front and rear wheels  102 ,  104  as enabled by the spokeless wheels that are open in the center region of the wheels. 
     The bicycle can be collapsed manually, or the motors in the front and rear wheels can aid in (or completely and autonomously execute) this transformation. The front and back wheels are first swiveled a bit off alignment. Then the front wheel is driven in reverse and the back wheel is driven forward in a back a forth motion to achieve the auto-folding. 
     From the collapsed configuration of  FIG. 11 , the bicycle can be further compacted as illustrated in the side view of  FIG. 12 . Here, the left pedal  114  is swiveled up and the right pedal  116  is swiveled down to position each fully within the open region within the generator-motor  108 .  FIG. 12  also shows that the upper frame tube segments  160  and  166  extend alongside the wheels  102  and  104 . This effect results from the mating surfaces  1202 ,  1206  of the upper segments  160 ,  166  to the mainframe tubes  118  and  120  being perpendicular to the swivel axes  158 ,  172  but angled relative to the center axes of the tubes  118  and  120 . In  FIG. 12 , the handlebar has been removed from the handlebar support  124 , which is now swiveled about the swivel joint  154  to be close to the wheel  102 . Similarly, the seat has been removed from the seat support  128 , which is pivoted about swivel joint  156  to be close to the rear wheel  104 . The seat has been placed inside the wheels and may be magnetically coupled to or spring clamped to or otherwise coupled to the wheels to serve as a shoulder pad in carrying the collapsed bicycle on one shoulder. The handlebar  122  may be clamped to or magnetically or otherwise coupled to one or both wheels. In  FIG. 12 , it is shown positioned to the right of the wheels. 
     It can be understood that, if the bicycle were collapsed about vertical axes  158 ,  172 , the wheels  102 ,  104  would collide with the midframe  106  before the wheels and midframe reached a parallel orientation. To collapse the wheels into a parallel configuration, double axis joints  162 ,  168  can be used. But to avoid the complexity of a double axis joint, the system shown relies on single axis joints  162 ,  168  where the swivel axes  158 ,  172  are slightly tilted from vertical, one to one side and the other to the other side. The result is best seen in  FIG. 13 , which shows an end view of the collapsed bicycle of  FIG. 12 . In this view, the wheels  102  and  104  are no longer vertical as they were in the standard riding configurations of  FIGS. 1 through 7 . With the tilted swivel axes, the wheels are positioned closer together at the upper end but are split apart at the lower end. To allow for the more compact folding, a notch  174  ( FIG. 1 ) is provided in the frame tube  118 , and a notch  176  is provided in the frame tube  120 . In this folded configuration, the rear wheel  104  rests in the notch  174 , and the front wheel  102  rests in the notch  176 . The result is a collapsed configuration in which the wheels are no longer parallel but which allows the wheels to roll in parallel directions. The spread of the wheels at ground also leads to greater stability. The wheels close to each other at the top bring the handlebar and seat supports closer together in the axial direction toward a center plane for riding embodiments described below. 
       FIGS. 14 and 15  show alternative positions of the handlebar  122  coupled to the collapsed bicycle. As before, the handlebar may be clamped or magnetically coupled to one or both folded wheels. 
       FIGS. 16-19  show the bicycle in the collapsed configuration but with the handlebar  122  and seat  126  and their respective supports retained at the joints  154 ,  156  as shown in the standard configuration of  FIG. 1 . When first collapsed, both the handlebar and seat would face in reverse directions as the handlebar  122  is shown in  FIG. 11 . After collapse, the end segments  160  and  166  of the frame tubes  118  and  120  are directed toward each other. The seat support  128  and handlebar support  124  are offset from each other slightly in the axial direction of the wheels due to the offset of the wheels. To obtain the position shown in  FIG. 16 , the handle bar  122  is rotated 180° on its support  124 , and the support  124  is swiveled forward, away from the seat, on swivel joint  154 . Similarly, seat  126  is rotated 180° on its support  128 , and the support  128  is swiveled away from the handlebar on its swivel joint  156 . 
     In this configuration, the bicycle may be utilized as a unicycle that has particular application as an exercise bicycle (exercycle) for exercise in a room or other close space. In this exercise configuration, the bicycle can be used to exercise the body by providing a velocity dependent torque to the pedals. The electrical energy generated by the mid motor-generator  112 ,  114  is stored in the energy storage modules. With gyro and accelerometer sensing, the electronics may retain the unicycle in a stable, stationary position by dithering forward and reverse rotation of the wheels. If needed, the bike in this configuration can be programmed to drive in a circle, figure eight or some other arbitrary path during exercise. Indeed, the path travelled (it might be in a living room, for example) might be coupled to a display, perhaps mounted to the handlebar, of some interesting path (e.g., mountain path) or circuit (e.g., bike race circuit). 
       FIGS. 17-19  provide the top, front and rear views of the unicycle configuration of  FIG. 16 . 
       FIGS. 20-26  illustrate walker configurations of the bicycle of  FIG. 3 . To obtain this configuration, both wheels  102  and  104  are swiveled about swivel joints  162 ,  168  to the same side of the midframe by 90° and then locked in place. The end segments  160  and  166  of the frame tubes  118  and  120  also extend to the side at 90°. The pedals  114 ,  116  are swiveled into the collapsed position within the generator  108 , and the handlebar and seat are removed. The handlebar support  124  and seat support  128 , with their associated torque sensors, extend alongside the wheels as walker handles. The walker is powered and can steer under computer control by differential torques generated by the two wheels. Three axis accelerometers and three axis gyros in the bike control system are used to servo control the bike in this walker configuration to remain in the orientation as shown. A person using the bike in this walker configuration holds the bike via the handlebar support bar  124  (in one hand) and the seat support bar  128  (in the other hand). The multi-axis force/torque sensors in supports  124  and  128  are used to detect direction and speed commands from the human. 
     The bicycle in this walker configuration can also function as an autonomous robot (i.e. can function without a human “driver”). 
       FIG. 21  shows an end view of the walker of  FIG. 20 ;  FIG. 22  shows a side view of the walker; and  FIG. 23  shows a top view. 
     The user of the walker may also simply hold the top bar  310  of the additional frame segment  302  of the midframe. In the configuration of  FIG. 24 , the midframe addition  302  is tilted toward the user on pins  2401  extending through the front frame tube  118  and rear frame tube  120 . This moves the top bar  310  closer to the user for more convenient grasping. 
       FIG. 25  is an end view of the walker of  FIG. 24  with the frame addition  302  tilted toward the user, and additionally shows the handlebar mounted between the front and rear wheels. The handlebar may be mounted by magnetic coupling or spring clamp or other temporary attachment mechanism. The handlebar adds to the rigidity of the system. In a configuration where the midframe addition  302  is not included, the handle  122  would then provide an additional feature to be grasped by a user with possible control through the end hand grips  208  and  210 .  FIG. 26  shows a perspective view of the configuration of  FIG. 25 . 
       FIGS. 27-31  illustrate yet another configuration of the bicycle, a chariot configuration. Here, the bicycle is configured as in  FIG. 20  but the wheel stators of the front and rear wheels  102  and  104  are rotated 90° about their center axis. This brings the midframe  302  low, alongside and parallel to the ground. This configuration can be used to transport packages supported on the midframe as illustrated in  FIG. 31  or a user may stand on the midframe. In the latter case, the handlebar  122  might be connected between the stators of the wheels  102  and  104  to serve as a handlebar with handle grip controls to be gripped by the user. The handlebar support  124  and the seat support  128  might still be used by the user, but to avoid having to squat, extensions, not shown, would be added to the supports. In either case, the multi-axis force/torque sensors in the supports  124  and  128  are used to detect direction speed commands from the user. The bicycle in this chariot configuration can also function as an autonomous robot (i.e. it can function without a human driver) and might be used for package delivery among other tasks. 
       FIG. 29  shows an end view of the chariot configuration with the handlebar  122  mounted, and  FIG. 30  is a side view of the chariot configuration without the handlebar. 
       FIGS. 32-37  illustrate yet another configuration, a compact robotic configuration. This configuration is like the chariot configuration of  FIGS. 27-31 , but the wheels  102 ,  104  have been swiveled further to the same side of the midframe  106  to meet where they can be clamped together at  3202 . As with the chariot configuration, this configuration can carry a package as illustrated in  FIG. 37  and can be operated autonomously. 
       FIGS. 38-41  illustrate a modification of the configuration of  FIGS. 32-37  to enable it to be ridden by a human user while also carrying a package on the midframe. To that end, a top bar  3802  is coupled at the intersection of the wheels at  3202  by means of a coupling  3804 . The handlebar  122  is positioned at one end of the bar  3802  and the seat  126  is positioned at the other end of the bar. The unit can be controlled by the handgrips  208  and  2010  on the handlebar  122 .  FIG. 38  shows a perspective view of this configuration;  FIG. 39  shows the side view;  FIG. 40  shows an end view; and  FIG. 41  shows a top view. As noted, this configuration allows a package to be carried as in  FIG. 36 . Torque sensors in the handlebar support  124  may also be used to receive direction and speed commands from the human. As in all other configurations, three axis accelerometers and three axis gyros enable the bicycle control system to keep the bike upright as shown. Also, as in all other configurations the unit may be operated as an autonomous robot without a human driver. 
       FIGS. 42-46  illustrate yet another configuration, a seated configuration. Here, the bicycle is configured as in the walker configuration of  FIGS. 21-24  except that the midframe addition  302  is pivoted on pins  2401  all the way to a horizontal position. A user may sit on the bar  310  and control the seated bicycle using the handlebar and seat supports  124 ,  128  as control handles. As illustrated in  FIG. 43 , a web  4302  may be coupled to the frame tubes  118  and  120  and to the midframe addition  302  to increase the comfort of the user with a seat  4306  and a back  4308  and also to provide additional support to the midframe edition  302  through the sides  4304  of the web. 
       FIG. 44  shows an end view of this configuration without the web;  FIG. 45  shows a side view of this configuration without the web; and the  FIG. 46  shows a top view of this configuration without the web. 
     As with all other configurations, the multi-axis force/torque sensors may be used to detect direction and speed commands from the human user. Accelerometers and gyros may be used to maintain the unit in the stable upright position as illustrated, and the unit may be operated as an autonomous robot without a human driver. 
       FIG. 47  illustrates the electronic and the power components of the bicycle. The front motor-generator  4702  corresponds to the stator  130 , rotor  138  forming the front motor-generator. Rear motor-generator  4704  corresponds to the rear stator  142  and rotor  150 . Pedal generator-motor  4706  corresponds to the generator-motor  108 . These motor-generators charge the power storage  4708  and are powered from the power storage  4708  through power electronics  4710 . As previously noted, the power storage may be in batteries, capacitors or a combination of the two. Charge-discharge of the storage and powering of the motor-generators is controlled by a processor  4712  through the power electronics  4710 . The processor responds to internal software programming and to external inputs. Inputs include speed control  4714  which may be obtained from the right grip  210  of the handlebar  122 . Stiffness control  4716  may, for example, be fed from the left grip  208 . Multidirectional torque input may be obtained from torque sensors  4718  that may, for example, be mounted in the handlebar support  124  and seat support  128 . Accelerometers  4720  and gyros  4722  mounted anywhere within the midframe provide inputs to the processor to enable the bicycle to stand in a stable upright position in each of the many configurations. The front and rear solenoids used to lock the swivel joints  162 ,  168  are controlled by the processor. Other inputs and outputs to and from the processor may also be provided from and to a controller such as an application in a smart phone. The components  4708 ,  4710 ,  4712 ,  4720  and  4722  may all be mounted within the base midframe  106  of  FIGS. 1 and 2  and, optionally, in the midframe addition  302 . 
     While example embodiments have been particularly shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the embodiments encompassed by the appended claims.