Self-stabilizing wheeled vehicle and related methods

Abstract

The invention relates to a self-stabilizing system including a self-stabilizing wheeled vehicle. A motor-powered vehicle has two wheels arranged side-by-side and a vehicle body whose center of gravity is closer to the ground than the centers of rotation of the wheels. Counter torque from the motor, which would otherwise cause the vehicle to tilt forward or backward, is converted into movement of the vehicle body relative to the wheels, thus keeping the vehicle body level during velocity changes. Bias mechanisms may be used to ensure that the vehicle body travels the appropriate distance from the wheels for a given value of acceleration and returns toward neutral when torque is reduced.

Description

U.S. Patent Application forSELF-STABILIZING WHEELED VEHICLE AND RELATED METHODSInventor: Shane ChenCROSS-REFERENCE TO RELATED APPLICATIONS[1] This application claims the benefit of priority to U.S. Provisional Application No. 63438504, filed January 11, 2023, entitled Two-wheeled Vehicle, U.S. Provisional Application No. 63525718, filed July 9, 2023, entitled Two-wheeled Vehicle 3, U.S. Provisional Application No. 63545193, filed October 22, 2023, entitled Car, and U.S. Provisional Application No. 63546521, filed October 30, 2023, entitled Two-wheeled Vehicle, which applications are incorporated herein by reference in their entirety and for all purposes.BACKGROUND OF THE INVENTION[2] In the field of transportation and mobility, cars and other vehicles for carrying occupants and cargo are commonly designed to have four wheels, arranged two to an axle. Although vehicles with fewer than four wheels exist and are used for various purposes, the four-wheel, two-axle configuration is the most popular configuration for vehicles intended for multiple occupants, large payloads, and / or high speeds because it is inherently stable. However, two-wheeled vehicles can have various advantages over four-wheeled vehicles. Depending on the type of two-wheeled vehicle, these advantages can include production economy, fuel efficiency, maneuverability, smaller footprint leading to ease of parking and storage, and the like. A car designed to have only two wheels could benefit from those advantages, but existing two-wheel technology used in smaller vehicles is not sufficiently stable for widespread practical use in cars and other similar vehicles.[3] Vehicles with two wheels may have the wheels arranged in-line or side-by- side. Various examples exist and are used in vehicles intended for a small number of occupants (most commonly only a single occupant) and minimal cargo. These two-wheeledvehicles typically require some skill on the part of the operator to maintain balance, and the balance of the vehicle is typically subject to influence from weight shifts from the riders and / or cargo, which both reduces the comfort of the riders (since they must be careful of their position or stance) and requires the operator to be prepared to compensate for unwanted balance shifts. Arranging the two wheels side-by-side and placing the center of gravity of the vehicle body (including payload) below the centers of rotation of the wheels makes the vehicle stable at rest, but counter torque from acceleration or deceleration would cause the vehicle body to tilt forward or backward. Current technology for dynamic autobalancing requires the vehicle’s center of gravity to be above the centers of rotation of the wheels and requires a significant reserve of power at all times to perform balancing functions (wherein balancing fails if insufficient power is available), which poses a safety liability at high speeds. As a result of these disadvantages, two-wheeled vehicles have been limited in the number of occupants, size of cargo, and / or speed of travel which are deemed safe. Nevertheless, two-wheeled vehicles for carrying relatively small payloads remain popular in cases where their advantages are worth their disadvantages.[4] Although significant progress has been made in recent years with respect to wheeled vehicles that can ensure stability and efficient movement under various conditions, there is still a need in the art for new and improved mobility systems and related methods. Specifically, there is a need for vehicle designs which can benefit from the advantages of two-wheeled vehicles in areas such as convenience and maneuverability while being much more stable than existing two-wheeled vehicles. The present invention fulfills this need and provides further related advantages.BRIEF SUMMARY OF THE INVENTION[5] In brief, a two-wheeled vehicle with its center of gravity below the wheel axis can be stable at rest. However, when it accelerates or decelerates, the counter torque from driving the wheels or applying braking causes the body to tilt forward or backward. This invention addresses this issue by converting the counter torque into forward or backward movement of the body in relation to the wheels, or alternatively and / or additionally, can elevate the body to counteract the tilting counter torque.[6] In accordance with several of the various embodiments disclosed herein, a self-stabilizing two wheeled system is provided. A vehicle equipped with two wheels arranged side-by-side has the center of the wheels positioned farther from the ground than the center of gravity of the vehicle body, making the vehicle stable at rest. To prevent destabilization during acceleration or deceleration, the vehicle body is capable of moving relative to the wheels and does so during velocity changes to eliminate forward or backward tilting due to counter torque. Bias mechanisms, such as springs, bias motors, mechanisms using gravity as a biasing force, or a combination of those, may be used to ensure that the vehicle body travels the appropriate distance from the wheels for any given value of acceleration, and returns toward neutral when driving or braking torque is reduced. Mechanisms for adjusting the pitch angle of the vehicle body according to the slope of the ground, incorporating a suspension system including an option for regenerating energy through the suspension system, and other relevant functions are described below.[7] These and other aspects of the present invention will become more readily apparent to those of ordinary skill in the art when reference is made to the following detailed description in view of the accompanying drawings.BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS[8] The drawings are intended to be illustrative of certain preferred embodiments of the present invention. Like reference numerals have been used to designate like features throughout the several views of the drawings.[9] FIG. 1 illustrates an elevated side perspective view of a self-stabilizing wheeled vehicle in accordance with a first embodiment of the present invention, wherein the left-hand wheel is cut in half to illustrate the inside of the wheel.

[0010] FIG. 2 illustrates an elevated side perspective view of a self-stabilizing wheeled vehicle in accordance with an alternative version of the embodiment of FIG. 1, adding an adjustment motor.

[0011] FIG. 3 illustrates an elevated side perspective view of a self-stabilizing wheeled vehicle in accordance with an alternative version of the embodiment of FIGS. 1-2, having a motor instead of a spring used as a bias mechanism.

[0012] FIG. 4 illustrates an elevated side perspective view of a self-stabilizing wheeled vehicle in accordance with an alternative version of the embodiment of FIGS. 1-3, having a motor and a spring used together as a bias mechanism.

[0013] FIG. 5 illustrates an elevated side perspective view of a self-stabilizing wheeled vehicle in accordance with an alternative version of the embodiment of FIGS. 1-4, having a different arrangement to the wheel support structures.

[0014] FIG. 6 illustrates a view of a forward-facing self-stabilizing wheeled vehicle in accordance with an alternative version of the embodiment of FIGS. 1-5, which has a different arrangement of the drive wheel and has a suspension system.

[0015] FIG. 7 illustrates an elevated side view of the self-stabilizing wheeled vehicle of FIG. 6.

[0016] FIG. 8 illustrates an enlarged view of a wheel of the self-stabilizing wheeled vehicle in FIGS. 6-7.

[0017] FIG. 9 illustrates a perspective view of a forward-facing self-stabilizing wheeled vehicle in accordance with a second embodiment of the present invention.

[0018] FIG. 10 illustrates an enlarged view of a wheel of the self-stabilizing wheeled vehicle of FIG. 9.

[0019] FIG. 11 illustrates an enlarged view of a wheel of an alternative version of the self-stabilizing wheeled vehicle of FIGS. 9-10.

[0020] FIG. 12 illustrates a front perspective enlarged view of the wheel of FIG. 11.

[0021] FIG. 13 illustrates a third embodiment of a self-stabilizing wheeled vehicle in accordance with the present invention having a single drive motor that drives both wheels, wherein the outer portions of the vehicle body are removed to expose the drive system.

[0022] FIG. 14 illustrates an alternative version of the self-stabilizing wheeled vehicle of FIG. 13.

[0023] FIG. 15 illustrates a perspective view of a self-stabilizing wheeled vehicle in accordance with a fourth embodiment of the present invention.

[0024] FIG. 16 illustrates a side perspective view of the self-stabilizing wheeled vehicle of FIG. 15.

[0025] FIG. 17 illustrates a side perspective view of an alternative version of the selfstabilizing wheeled vehicle of FIG. 15 and FIG. 16.DETAILED DESCRIPTION OF THE INVENTION

[0026] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols or markings have been used to identify like or corresponding elements, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting and are not necessarily to scale. Other embodiments may be utilized, and other changes may be made, without departing from the scope of the invention as defined by the appended claims.

[0027] Referring now to the drawings, the present invention is directed to a selfstabilizing wheeled vehicle that employs one or more self-stabilizing mechanisms as more particularly illustrated and described in the context of exemplary FIG. 1 - FIG.17.

[0028] In view of the foregoing, the embodiment presented in FIG. 1 depicts a vehicle equipped with two wheels, denoted as wheel 7, one on each side. Notably, the centers of these wheels are positioned above the center of gravity of the vehicle body, denoted as body 50. Body 50 may carry passengers, items, or any payload. As illustrated in FIG. 1, the left wheel is partially exposed to reveal its internal structure. Within wheel 7, there is a hub motor, as drive motor 3. Attached to the wheel rim are magnets 10, which constitute the rotor of motor 3 and rotate around motor stator 11 that is rigidly connected to shaft 1. The motor arrangement in Fig. 1 is an example of one motor configuration which may be used with the present invention. In other embodiments the motor may have speed reduction or other ways to drive the wheel. As shown, shaft 1 extends through a movable frame 2 and is supported by two bearings 9 situated within movable frame 2. At the other end of shaft 1, it is rigidly connected to gear 4. Movable frame 2 has the capability to move forward and backward along two rails, labeled as rails 8, mounted on body 50. While not shown here, bearings or other mechanisms are present between the movable frame 2 and the rails 8 to minimize friction. Alternative methods may be used to achieve movement of the movable frame relative to the vehicle body. The lower rail 8 features a linear gear on its upper surface, labeled as linear gear 5, which engages with gear 4. When the motor rotorinitiates the transmission of driving torque to wheel 7, the stator 11 must generate a counter rotating torque. This counter rotating torque rotates gear 4 in a direction opposite to the direction of the torque applied to wheel 7. The counter rotation of stator 11 moves body 50 linearly forward away from movable frame 2 when motor 3 accelerates wheel 7 forward, and moves body 50 linearly backward away from movable frame 2 when motor 3 accelerates wheel 7 backward. To maintain equilibrium, two torque springs, labelled as bias springs 6, are sleeved over shaft 1. The outer ends of springs 6 connect to movable frame 2, while the inner ends link to shaft 1 with opposite winding directions and preloaded tension. Bias springs 6 serve as a biasing element. Their resistance increases as body 50 moves away from its neutral position in either direction relative to movable frame 2 or the center of wheel 7. The neutral position is usually defined as the position where the center of gravity of body 50 and the center of wheel 7 are vertically aligned and body 50 is level. Motion of body 50 away from neutral position ceases when the resistance of spring 6 balances with the torque of motor 3. Notably, the more torque the motor 3 produces, the greater the distance body 50 can travel concerning movable frame 2. The magnitude of the motor's torque output determines how far the vehicle body can travel. When the torque is reduced, bias springs 6 retract body 50 to a correspondingly reduced distance. In the absence of torque, body 50 returns to its original neutral position. In some embodiments one bias spring may be used instead of two.

[0029] It's important to highlight that the diameter of gear 4 is intentionally set to be smaller than the diameter of wheel 7. This design choice results in motor 3 more easily driving gear 4 than wheel 7, and thus gear 4 starting to rotate before wheel 7, creating an initial forward shift of body 50 concerning movable frame 2 during acceleration. This adjustment prevents body 50 from tilting backward during acceleration. To initiate braking, either electric resistance may be applied to motor 3 (charging the battery) or physical braking may be applied between either the rotor of motor 3 or the wheel, and either stator 11 or shaft 1. When braking is applied, movable frame 2 moves relative to body 50 in the same direction as the vehicle's prior motion, before torque springs 6 reach equilibrium with the braking torque. This ensures that the center of gravity of body 50 is shifted backward, countering the braking torque, and preventing body 50 from tilting forward during deceleration. This embodiment has a configuration where gear 4 is smaller than wheel 7, butin other embodiments an alternative approach which accomplishes the same end may involve configuring the stator to move the body relative to the movable frame with a higher speed reduction than the rotor speed reduction for driving the wheel moving on land. Since the left and right sides of body 50 have the same configuration as described above, the movable frames on each side of the body are independently driven by their respective motors and may move independently. Each motor's electrical wires may pass through the center of the shaft and connect to the vehicle's control circuit. During the rotation of the stator, which may be more than one cycle of rotation, the wires may twist. To accommodate this, the wires may be enclosed in a coil spring or another suitable method to facilitate twisting. Alternatively, an electrical contact brush may be employed for wire connections, allowing for continuous rotation.

[0030] Fig. 2 is the same embodiment as Fig. 1 but with the addition of an adjustment motor 42 for adjusting the neutral position of body 50 relative to movable frame 2 or the center of the wheel 7. Adjustment motor 42 is mounted on movable frame 2 and has a driving worm shaft 41 engaging a worm gear 40 connected to the outer end of bias spring 6. Position sensor 31 and a control circuit may be added in the body 50. In case of any occupancy shift in the vehicle, or when operating on an inclined surface, the control circuit controls motor 42 to rotate spring 6, thereby adjusting body 50 forward or backward relative to movable frame 2 to keep body 50 parallel to the ground as detected by position sensor 31. An inclination sensor may be added to detect the slope of the ground. Motor 42 may also be used to purposely move body 50 away from its neutral position to tilt it towards the ground for boarding. Notably, the worm shaft / gear system does not allow worm gear 40 to reverse rotate worm shaft 41, so the neutral position of body 50 can only be adjusted by motor 42. Other embodiments may use alternative ways for adjusting the neutral position of the body relative to the movable frame while not allowing reversed rotation.

[0031] Fig. 3 is the same embodiment as Fig. 1 but differs in that springs 6 are replaced with bias motor 43. Bias motor 43 has its stator fixedly mounted to movable frame 2 and its rotor connected to and sharing shaft 1. So, gear 4 is driven by both motor 43 and stator 11 of drive motor 3. Bias motor 43 performs a function analogous to springs 6 in Fig. 1 and is momentarily used as a generator to store energy in a battery while creating resistance when body 50 is moved away from its neutral position during acceleration anddeceleration (analogous to loading of springs 6 in Figs. 1 ). Motor 43 then releases energy by driving body 50 back to its neutral position when acceleration and deceleration cease (analogous to spring 6 pulling the body back to neutral position). Position sensor 31 and a control circuit may be mounted in body 50. In other embodiments the position sensor and control circuit may be located on movable frame 2 or anywhere that is synchronized with the orientation of body 50. During acceleration or deceleration, the control circuit uses data from position sensor 31 to detect when the angle of body 50 relative to the ground deviates from a desired angle. Based on the magnitude of the deviation, the control circuit determines how much current or voltage must be output to charge the battery (i.e., the charging rate) to create the required amount of resistance against the driving torque from stator 11 in order to maintain body 50 at the desired angle. When the acceleration and deceleration cease, the control circuit uses data from position sensor 31 to determine the right amount of torque applied from motor 43 to drive body 50 back toward its neutral position and maintain its desired angle. The bias motor may also be a linear motor, instead of the rotating motor, mounted on the movable frame for example, that moves the vehicle body forward or back. This electrical resistance and bias system perform a function analogous to that of springs 6 in Fig. 1 and motor 42 in Fig.2. The desired angle at which the body is maintained is usually horizontally level unless the vehicle is on a slope. The inclination sensor may be used to detect the slope of the ground and automatically adjust the desired angle accordingly. A distance sensor may be added to detect how far the body has traveled relative to the movable frame or center of the wheel. Based on the distance data, the control circuit progressively increases the charging rate while the body is moving away from its neutral position, and progressively decreases the driving torque of motor 43 while driving body 50 back towards its neutral position, thus simulating the function of spring 6. The position sensor may also be used to assist in facilitating more accurate vehicle control and maintaining the desired angle.

[0032] In some embodiments, such as the one shown in Fig. 4, bias motor 43 may coexist with spring 6 instead of replacing each other, wherein both may drive shaft 1 / gear 4 and assist each other in performing the same function. For example, motor 43 may move the body back to its neutral position when spring 6 is unable to fully do so due to friction, and spring 6 may assist motor 43 in providing the needed amount of resistance, which may berequired in cases where design considerations limit the size of motor 43, or when resistance from battery charging may be insufficient in some situations, especially at times when the battery is already in a high state of charge. Adjustment motor 42 may also be added and connected with spring 6 to adjust body 50’ s neutral position for this embodiment.

[0033] Another variation on the embodiment of Fig.3-4 has the rotor of motor 43 driving shaft 1 via a speed changing assembly instead of directly connecting to shaft 1. The speed changing assembly may be a speed reduction with gears or belt / pulley. This configuration may be used to make regeneration or driving from motor 43 more effective.

[0034] Fig. 5 is an alternative configuration that can be applied to Fig. 1-4. It has movable frame 2 connected to the movable frame of the opposite side wheel assembly of the vehicle, allowing both wheel assemblies to move in unison relative to body 50. Motor 43 may be only required on one of the wheel assemblies. Alternatively, the connection of the two movable frames may be inside of body 50, and motor 43 may be located inside of the body 50.

[0035] The embodiment in FIG. 6-8 employs the same method for distributing motor torque as in Fig.1-5 but encloses movable frame 2 and spring 6 inside wheel 7 and, in addition, incorporates an in-wheel suspension system. FIG. 6 reveals the movable frame 2 extending into the wheel through a large central opening, labeled 32, in wheel support 17, while the opposite side of wheel 7 is covered by wheel support 18. In Fig. 7, support 18 is not pictured, exposing a rotatable bracket 23 rotatably connected to central opening 32 of support 17 via a large thin section bearing 33 (shown in Fig. 6) on one side, and to support 18 via a small bearing 20 on the other side, both coaxial with wheel 7. Alternatively, rotatable bracket 23 may be arranged not to connect to central opening 32 of support 17 and may have two bearings on the same connection with support 18. Motor 3 is rotatably connected to rotatable bracket 23 along axis 19 which is outside of central opening 32. FIG. 8 displays half of the rotatable bracket 23 removed and reveals the protruding movable frame 2, which is also rotatably connected to motor 3 and the rotatable bracket 23 along the same axis 19. The rotor of motor 3 features gear 22 that engages with ring gear 21 to drive wheel 7. The stator of motor 3 drives gear 4 via shaft 27 (coaxial with axis 19), two pulleys 26, chain or belt 24, and shaft 1. Gear 4, in turn, drives linear gear 5 to facilitate movement of vehicle body 50 concerning movable frame 2. This mechanism is analogous to theembodiment in FIG. 1 -4, with the only difference being the inclusion of two pulleys 26 and a chain or belt 24 due to the motor's altered location on movable frame 2. Alternatively, the stator of motor 3 may be fixedly connected to shaft 1 driving gear 22 via pulleys 26 and belt 24. Pulleys and belts may be replaced with gears or other means to transfer power. Spring 6 serves as a biasing component. A suspension system, involving shock absorber 25, has one end pivotally connected to the movable frame 2 and the other end pivotally connected to the rotatable bracket 23. As a result, the wheel can pivot up and down along pivotal axis 19 concerning the suspended movable frame 2, with shock absorber 25 offering damping capabilities. Furthermore, since the motor moves up and down along the rim during shock compression and decompression, it can be electronically dampened to regenerate energy for storage in the battery. The central opening 32 can be covered with a flexible membrane material that allows vertical wheel movement relative to the movable frame 2 while sealing the wheel's internal components from the external environment.

[0036] An alternative method for propelling the wheel with in-wheel suspension is the friction drive detailed in my US patent application US23 / 76398 (wheel structure).

[0037] The embodiment shown in Fig. 9-10 has the same rail structure and movable frame configuration as in Fig.1-8 but introduces an alternative method for distributing the drive torque from the drive motor. In Fig. 9-10 the alternative method employs a differential system, denoted as 112, to divide the torque of drive motor 103 between wheel 107, moving on the ground, and gear 104, moving body 150 relative to movable frame 102. This differential system mirrors the technology used in automotive vehicle differential drives. In Fig.9-10 drive motor 103 is firmly affixed to movable frame 102 and powers gear 114 via gear 116 connected to the motor rotor. Gear 114, in turn, rotates two pinion gears, labeled as 113, positioned both at the top and bottom. These two pinion gears 113, in a cascading manner, drive the two side gears, labeled 115, situated to the left and right of pinion gears 113. As illustrated in FIG. 10, right side gear 115 propels wheel 107 via the right drive shaft, while left side gear 115 propels gear 104 through the left drive shaft. An inner shaft is positioned inside both the right and left drive shafts, providing structural support, and enabling the rotation of both drive shafts at distinct speeds. Gear 114 is mounted on a bearing that sleeves over the right drive shaft rotating independently from the right drive shaft. (The configuration described above is known as a differentialsystem in the automotive industry.) Gear 104 and bias spring 106 serve the same function as gear 4 and spring 6 in Fig. 1, but with linear gear 105 engaging on the top instead of the bottom of gear 104 in order to apply the propelling force to body 150 in the same direction as the wheels are rolling. This is because the left and right torque output directions of differential system 112 are the same, unlike the opposite torque output directions from the motor rotor and stator as in Fig. l . The braking can be applied electronically via motor 103, or physically between movable frame 102 and either motor 103 drive shaft, gear 116, 114, or other locations to stop the input rotation to differential system 112. The embodiment in Figs. 9-10 shows that the wheel assembly, including movable frame 102, motor 103, spring106 and differential system 112, is partially within the envelope of wheel 107.Alternatively, the wheel assembly may be entirely within wheel 107’ s envelope as in Fig.11-12.

[0038] Figs. 11-12 reveal the movable frame 102 extending into wheel107 (cut in half to show inside) through a large central opening 132 in wheel support 117, while the opposite side of wheel 107 is covered by wheel support 118, similar to the embodiment in Figs. 6-8. Rotatable bracket 123 (cut in half to show inside) is rotatably connected to wheel support 118 via bearing 120 on the center axis of wheel 107. There may be a second bearing on the same shaft in addition to bearing 120 for greater strength. Alternatively, the end of rotatable bracket 123 at wheel support 117 may connect to central opening 132 of support 117 via a large thin section bearing as in Figs. 6-8. Movable frame 102 is rotatably connected to rotatable bracket 123 at both ends along axis 119 which is off centered from the center axis of wheel 107. (It is possible to only connect at one end with double bearings). Drive motor 103, differential system 112, and bias spring 106 are mounted on movable frame 102 having the same functions as in Figs. 9-10, but the right drive shaft of differential system 112 propels wheel 107 via gear 122 engaging ring gear 121 mounted on wheel support 117 (shows in Fig. l 1), instead of propelling wheel 107 directly. A suspension or shock absorber 125 is connected between movable frame 102 and rotatable bracket 123 serving the same function as in the embodiment in Figs. 6-8. Shock absorber 125 is partially broken away to show spring 106 behind in Fig. 12. Notably, axis 119 serves the same purpose as axis 19 in Fig.6-8 except that axis 119 is located inside of central opening instead of outside.

[0039] Fig. 13 shows an embodiment representing a vehicle having a single drive motor 203 that drives both wheels. The vehicle body 250 is simplified to show the principle. The shaft of drive motor 203 drives differential system 212 which splits the rotating torque to worm shaft 204 and to triangular drive shaft 236. Worm shaft 204 moves movable frame 202 (via a worm gear placed inside movable frame 202) forward and backward on two rails 208 mounted on vehicle body 250. Both wheels are driven by drive shaft 236 through another differential system 239 mounted on movable frame 202. Drive shaft 236 can rotate to drive differential system 239 while free to slide forward and backward within differential system 239. The drive shaft can be in other shapes other than triangular, so long as capable of rotatably driving differential system 239 while sliding longitudinally. Motor 238 is a steering motor for differential system 239. Controlling the direction and speed of rotation of motor 238 can provide differential speeds to the two wheels to steer the vehicle. Differential system 239 with steering motor 238 is a known technology used in vehicles such as tanks. Other kinds of tank steering systems known in the art may also be applicable for the present purpose. The split motor drive force from differential system 212 through worm shaft 204 moves body 250 relative to movable frame 202 and the wheels during acceleration and deceleration, as in all other embodiments above. Bias spring 206 biases movable frame 202 toward its neutral position when the torque of motor 203 is reduced or ceased. Bias spring 206 pulls a cable connected to pulley 246 which is synchronized with the rotation of worm shaft 204. The cable winds in one direction or the other on pulley 246 depending on the direction in which movable frame 202 is moving. Other mechanisms for moving body 250 relative to movable frame 202 and for biasing movable frame 202 toward a neutral position are possible without departing from the present invention.

[0040] The springs of embodiments in Figs. 6-13 may be replaced with a bias motor as in Fig. 3 and may also coexist with the bias motor as in Fig. 4. An adjustment motor for adjustment of the neutral position of the body may be also added as in Fig. 2. A position sensor, distance sensor, inclination sensor and control circuit may be added in these embodiments as well.

[0041] Fig. 14 shows a similar embodiment as in Fig.13 with a single motor driving both wheels, but the drive motor 203 and differential system 212 are mounted on movable frame 202 instead of on body 250. Two rails 208 and linear gear 205 are mounted on body250. On movable frame 202, the shaft of motor 203 drives differential system 212 that splits the rotating torque to gear 204 which drives linear gear 205 to move body 250 relative to movable frame 202, and to another differential system 239 that drives two wheels 207. Motor 238 is the steering motor for differential system 239 as in Fig. 13. Springs 206 have their one ends connected to body 250 and their other ends connected to middle bar 245 with its raised worm rack engaged to worm shaft 241 driven by adjustment motor 242 mounted on movable frame 202 for neutral position adjustment, operating on the same principle as in Fig. 2. Notably, the worm shaft / rack system does not allow middle bar 245 to reverse rotate worm shaft 241, so the middle bar can only be moved by motor 242. Bias motor 243 codrives gear 204 and coexists with bias spring 206 as in Fig. 4.

[0042] The drive motors featured in Figs. 9-14 are interchangeable with a fossil fuel engine or any other rotary power source. The arrangement and approach for the motor or differential system to drive the wheel and the vehicle body can be executed in various ways. Similarly, moving the vehicle body relative to the center of the wheel or movable frame can be achieved through diverse methods. The trajectory along which the vehicle body moves relative to the movable frame need not be linear; it can take a non-linear path, possibly following a curved trajectory. As an example, the vehicle body can be raised as it moves away from the neutral position relative to the movable frame. The arrangement of the spring for biasing the vehicle body relative to the center of the wheel or movable frame can also vary.

[0043] The bias spring as spring 6, 106, and 206 may be other types of spring. It may be a compression or extension coil spring, or it may be an air spring. One end of the spring may connect to the movable frame and the other end may connect to either the vehicle body or the shaft of the stator of the drive motor (either has the same effect). The spring connections may be arranged in other ways if it achieves biasing of the vehicle body relative to the center of the wheel. The number of springs used may be one or more. Two coil springs or air springs may be arranged to have one end connected to the movable frame and their other end connected to front and back portions of the body as in Fig.9. Other arrangements may alternatively be used to achieve the bias. With two air springs, they may be arranged to have pump and valves connected to their air chambers to increase or decreaseair pressure, or to increase one and decrease the other for adjustment of the neutral position of the body relative to the movable frame / wheel, as the same principle as the adjustment motor in Figs. 2 and 14. This may be useful for adjusting the vehicle’s pitch angle when traveling on a slope and / or when boarding.

[0044] FIG.15 and Fig.16 introduce an alternative embodiment and method for handling the counter drive torque from the drive motor. Instead of shifting the vehicle body forward and backward in relation to the center of the wheel, this approach employs counter drive torque to lift the body. In FIG.15, motor stator 311 of drive motor 303 is firmly attached to arm 328 via shaft 301. Arm 328 is pivotally connected to joint 329 on vehicle body 350. Due to the positioning of body 350's center of gravity 330 below the axis of joint 329, body 350 hangs vertically downward beneath axis of joint 329, maintaining stability, as depicted in FIG. 15. As motor 303 drives the wheel, the counter torque generated pivots the motor stator 311, causing arm 328 to pivot forward and elevate body 350 in relation to the wheel, as illustrated in FIG. 16. The elevation of body 350 follows a sine wave pattern, and the closer arm 328 approaches its level position (at a 90 -degree angle), the greater the torque demand. Consequently, higher acceleration results in a higher lift of body 350. When electrical or physical braking is applied to the motor or the wheel (between either the wheel or rotor and the stator for this embodiment), the arm 328 pivots backward. The extent of braking corresponds to the height to which arm 328 raises body 350. As drive or braking torque is decreased or discontinued, arm 328 returns to a lower position or its original configuration, as depicted in FIG. 15. This method utilizes gravity as a natural biasing force.

[0045] Fig. 17 shows an embodiment which differs from that of Fig. 15 and Fig. 16 in that joint 329 is positioned lower than body 350’ s center of gravity 330. In this configuration, body 350 is not inherently stable, and an auto balancing system is used to keep body 350 level. A typical method for self-balancing involves having a motor mounted on body 350 drive / rotate arm 328 toward dynamically balancing body 350 based on data from position sensors 331 mounted in body 350. Although it is possible to use an auto balancing system in a configuration where the axis of joint 329 is at the same height ascenter of gravity 330, the method of auto balancing is more effective when the axis of joint 329 is below center of gravity 330.

[0046] The present invention in Fig.1-17 can also be applied to tracked vehicles such as tanks, and vehicles with more than one wheel on each side with all or some of them driven. Because of the fore-aft stability of this invention, the front-and-back length of the track or length between the center of the wheels on each side can be reduced to a minimum. The driving system may have a left and right separate motor or a single motor or engine with a differential system and steering motor, or another suitable tank steering system.

[0047] The present invention can also be applied to single wheeled vehicles, whether motor- or human-powered. Human power can be used as a rotating power input going through a differential system to split the torque for moving the vehicle body and driving the wheel as described above.

[0048] While the present invention has been described in the context of the embodiments illustrated and described herein, the invention may be embodied in other specific ways or in other specific forms without departing from its scope or essential characteristics. Therefore, the described embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing descriptions, and all changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

CLAIMS1. A self-stabilizing wheeled vehicle, comprising: a body for carrying a payload; a wheel that has a central axis of rotation above the center of gravity of the body and which supports the body above the ground; and a rotating force generator that drives the wheel rolling on the ground and moves the body relative to the center of the wheel.

2. The self-stabilizing wheeled vehicle of claim 1, wherein the rotating force generator and the center of the wheel move in unison relative to the body.

3. The self-stabilizing wheeled vehicle of claim 1, wherein the rotating force generator is an electric motor.

4. The self-stabilizing wheeled vehicle of claim 1, wherein the rotating force generator is a fossil fuel engine.

5. The self-stabilizing wheeled vehicle of claim 1, wherein the rotating force generator is human power.

6. The self-stabilizing wheeled vehicle of claim 1, wherein the vehicle includes a bias element that resists the force moving the body relative to the center of the wheel.

7. The self-stabilizing wheeled vehicle of claim 6, wherein the bias element biases the body towards the center of the wheel.

8. The self-stabilizing wheeled vehicle of claim 6, wherein the bias element comprises at least one bias spring.

9. The self-stabilizing wheeled vehicle of claim 8, wherein the bias spring comprises an air spring.

10. The self-stabilizing wheeled vehicle of claim 6, wherein the bias element comprises a bias motor.11 . The self-stabilizing wheeled vehicle of claim 6, wherein the bias element comprises both a spring and a bias motor.

12. The self-stabilizing wheeled vehicle of claim 6, wherein the bias element operates using the force of gravity.

13. The self-stabilizing wheeled vehicle of claim 1, further comprising a movable frame coupled to the wheel, the bias element, and the rotatable force generator, wherein the movable frame is movable relative to the body.

14. The self-stabilizing wheeled vehicle of claim 13, wherein the movable frame and the center of the wheel move in unison relative to the body.

15. The self-stabilizing wheeled vehicle of claim 13, wherein the movable frame, the center of the wheel, and the rotatable force generator move in unison relative to the body.

16. The self-stabilizing wheeled vehicle of claim 13, wherein the movable frame is slidably engaged with a first rail mounted on the body.

17. The self-stabilizing wheeled vehicle of claim 1, wherein the force for moving the body relative to the center of the wheel is provided by the counter torque of the rotatable force generator.

18. The self-stabilizing wheeled vehicle of claim 1, wherein the rotatable force generator provides force for moving the body relative to the center of the wheel through a differential system.

19. The self-stabilizing wheeled vehicle of claim 1, wherein the movement of the body relative to the center of the wheel follows a linear path.

20. The self-stabilizing wheeled vehicle of claim 1, wherein the movement of the body relative to the center of the wheel follows a nonlinear path.

21. The self-stabilizing wheeled vehicle of claim 1, wherein the movement of the body relative to the center of the wheel is partly vertical.

22. The self-stabilizing wheeled vehicle of claim 1 , further comprising a second wheel.

23. The self-stabilizing wheeled vehicle of claim 22, comprising a left wheel and a right wheel, wherein the center of the left wheel and the center of the right wheel move relative to the body independently.

24. The self-stabilizing wheeled vehicle of claim 1 further comprising a third and fourth wheel.

25. The self-stabilizing wheeled vehicle of claim 1, further comprising an adjustment motor that is connected to the bias spring and adjusts the neutral position of the body relative to the center of the wheel.

26. The self-stabilizing wheeled vehicle of claim 1, further comprising a suspension mechanism that is connected to the movable frame.

27. The self-stabilizing wheeled vehicle of claim 26, wherein the suspension mechanism is contained inside of the wheel envelope.

28. The self-stabilizing wheeled vehicle of claim 1, wherein the rotating force generator is contained inside of the wheel envelope.

29. The self-stabilizing wheeled vehicle of claim 1, further comprising a rotatable bracket rotatably connected to the wheel center and coupled to the movable frame in a manner that guides the up and down movement of the movable frame relative to the wheel.

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