Patent Description:
A growing number of vehicles and/or robotic vehicles (or "robots") are becoming available for the purpose of transporting goods. The typical vehicles and/or robots use three, four or six wheels to provide propulsion and steering control during normal operation of the vehicle. Such vehicles and/or robots rely upon static stability and are designed for stability in all operating conditions via the location of the wheels. A separation distance between the wheels in the longitudinal, or backwards and forward direction, balances out applied torques due to gravity or inclines. Thus, in the typical vehicle stability is achieved by implementing an appropriate separation distance between the wheels in the longitudinal direction of the vehicle, thereby making the vehicle more resilient to disruptions along the lateral axis.

However, an issue exists in situations where attempts have been made to transport goods in two-wheeled vehicle having wheels located in the lateral, or side-by-side, direction, versus in the traditional longitudinal direction. The challenge of using the vehicles having only two wheels mounted in the lateral, side-by-side configuration is in maintaining dynamic stability of the vehicle during normal operation. This problem does not generally exist in vehicles having <NUM> or more wheels with longitudinal and lateral separation between wheels. <CIT> describes a two-wheeled vehicle that includes a chassis, and a first wheel carriage moveably coupled to, and longitudinally displaceable relative to the chassis. At least a first wheel is rotationally mounted on the first wheel carriage, and coupled to the chassis through the first wheel carriage. The two-wheeled vehicle further includes a first linear actuator system coupled to the first wheel carriage, and configured to longitudinally displace the first wheel carriage relative to the chassis. A first motor is mounted to the first wheel and the first wheel carriage. The first motor is configured to provide a drive energy to the first wheel, and to be displaced along with the first wheel carriage as the first wheel is displaced by the first linear actuator system.

Aspects of the invention are as set out in the appended claims.

In accordance with one aspect of the present disclosure, provided is a linkage-based shifting apparatus, comprising first and second arms, a first wheel rotatably coupled to a proximal end of the first arm, and a second wheel rotatably coupled to a proximal end of the second arm. A shifting assembly configured to couple to or form part of a chassis, the shifting assembly operatively coupled to the first and second arms to cause a relative shifting motion between the chassis and the first and second wheels.

In various embodiments, the first and second wheels share a common axis of rotation.

In various embodiments, the apparatus further comprises at least one motor configured to drive at least one of the first a second wheels.

In various embodiments, the apparatus further comprises a plurality of motors configured to independently drive the first and the second wheels.

In various embodiments, the apparatus further comprises a first pulley system operatively disposed between the first wheel and a first drive motor.

In various embodiments, the apparatus further comprises a second pulley system operatively disposed between the second wheel and a second drive motor.

In various embodiments, the shifting assembly is disposed between the first and second arms.

The shifting assembly further comprises a shifter motor configured to drive a capstan that is coupled to the chassis via at least one belt, strap, or rope.

The shifting assembly further comprises at least one gear coupling the shifter motor to the capstan.

The at least one gear comprises a first gear driven by the shifter motor and a second gear driven by the first gear, wherein the second gear is configured to rotate the capstan.

In various embodiments, the second gear and the capstan are operatively coupled together and coaxial.

In various embodiments, the shifting assembly further comprises an encoder operatively coupled to the second gear and/or capstan to measure an angle of rotation of the second gear.

In various embodiments, the shifting assembly is configured to cause the chassis to shift forward and/or rearward relative to the first and second wheels.

In various embodiments, the shifting assembly is configured to cause the chassis to shift forward relative to the first and second wheels for acceleration.

In various embodiments, the shifting assembly is configured to cause the chassis to shift rearward relative to the first and second wheels for deceleration.

In various embodiments, the shifting assembly is configured to cause the chassis to shift forward relative to the first and second wheels to place the body in a sitting position. In the sitting position, the first and second wheels can be in a still, non-rotating state.

In various embodiments, the shifting assembly is configured to cause the chassis to transition from the sitting position to an acceleration position.

In various embodiments, the shifting assembly is configured to cause the chassis to transition from an acceleration position to a deceleration position.

In various embodiments, the shifting assembly is configured to cause the chassis to transition from the deceleration position to the sitting position.

In accordance with other aspects of the inventive concepts, provided is a mobile carrier system, comprising a body including a chassis, first and second arms, a first wheel rotatably coupled to a proximal end of the first arm, and a second wheel rotatably coupled to a proximal end of the second arm. A shifting assembly is coupled to or integral with the chassis, wherein the shifting assembly is also operatively coupled to the first and second arms to cause a relative shifting motion between the chassis and the first and second wheels.

In various embodiments, the system further comprises at least one motor configured to drive at least one of the first and second wheels.

In various embodiments, the system further comprises a plurality of motors configured to independently drive the first and second wheels.

In various embodiments, the system further comprises a first pulley system operatively coupled between the first wheel and a first drive motor.

In various embodiments, the system further comprises a second pulley system operatively coupled between the second wheel and a second drive motor.

In various embodiments, the shifting assembly further comprises a shifter motor configured to drive a capstan configured to couple to the chassis via at least one belt, strap, or rope.

In various embodiments, the shifting assembly further comprises at least one gear operatively coupling the shifter motor to the capstan.

In various embodiments, the at least one gear comprises a first gear driven by the shifter motor and a second gear driven by the first gear, wherein the second gear is configured to rotate the capstan.

In various embodiments, the second gear and the capstan are operatively coupled and coaxial.

In various embodiments, the shifting assembly is configured to cause the chassis to transition from the acceleration position to a deceleration position.

In various embodiments, the body defines a storage compartment.

In various embodiments, the system further comprises a set of user interface devices.

In various embodiments, the set of user interface devices comprises one or more button, touch screen, sensor, camera, range finder, light emitting device, audio input device, and/or audio output device.

The present invention will become more apparent in view of the attached drawings and accompanying detailed description. The embodiments depicted therein are provided by way of example, not by way of limitation, wherein like reference numerals refer to the same or similar elements. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating aspects of the invention. In the drawings:.

Various aspects of the inventive concepts will be described more fully hereinafter with reference to the accompanying drawings, in which some exemplary embodiments are shown. The present inventive concept may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein.

It will be understood that, although the terms first, second, etc. are be used herein to describe various elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another, but not to imply a required sequence of elements. For example, a first element can be termed a second element, and, similarly, a second element can be termed a first element, without departing from the scope of the present invention.

It will be understood that when an element is referred to as being "on" or "connected" or "coupled" to another element, it can be directly on or connected or coupled to the other element or intervening elements can be present. In contrast, when an element is referred to as being "directly on" or "directly connected" or "directly coupled" to another element, there are no intervening elements present.

It will be further understood that the terms "comprises," "comprising," "includes" and/or "including," when used herein, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.

Spatially relative terms, such as "beneath," "below," "lower," "above," "upper" and the like may be used to describe an element and/or feature's relationship to another element(s) and/or feature(s) as, for example, illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and/or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" and/or "beneath" other elements or features would then be oriented "above" the other elements or features. The device may be otherwise oriented (e.g., rotated <NUM> degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Exemplary embodiments are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized exemplary embodiments (and intermediate structures). Thus, exemplary embodiments should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing.

To the extent that functional features, operations, and/or steps are described herein, or otherwise understood to be included within various embodiments of the inventive concept, such functional features, operations, and/or steps can be embodied in functional blocks, units, modules, operations and/or methods. And to the extent that such functional blocks, units, modules, operations and/or methods include computer program code, such computer program code can be stored in a computer readable medium, e.g., such as non-transitory memory and media, that is executable by at least one computer processor.

A growing number of vehicles or robotic vehicles (or robots) are becoming available for the purpose of transporting goods. The typical vehicles use three, four or six wheels to provide propulsion and steering control. Such vehicles rely on static stability and are designed for stability in all operating conditions via the location of the wheels. A separation distance in the longitudinal, or backwards and forward direction balances out applied torques due to gravity or inclines experienced by the vehicle during normal operation (e.g., braking, acceleration, and deceleration). The greater the separation distance (wheelbase), the more resilient to disruptions along the longitudinal axis the vehicle will be.

An alternate approach involves using a two-wheeled vehicle with the wheels located in the lateral or side-by-side direction. Such a vehicle is particularly maneuverable if the two wheels are decoupled such that they are independently propelled. The turning radius can be as small as the one half the distance between the wheels, if one wheel is propelled forward and the other backward, or to any greater degree via increasing the difference in speed between the inner and outer wheel of the turn. However, the challenge of using such a two-wheeled vehicle with the wheels located in the lateral, or side-by-side direction is that it must be dynamically stabilized to maintain the vehicle's vertical orientation, which is a requirement for most applications. Propulsion of such a laterally-mounted, two-wheeled vehicle may be accomplished by applying torque at the center of the vehicle wheel(s) with a motor, potentially with a gearbox to optimize motor performance. Alternatively, the wheel could be propelled with a rim drive.

Dynamic stabilization, also referred to as active balancing, is a technique in which a control system actively maintains the stability of the vehicle while it is operating, e.g., driving, turning. In a laterally-wheeled vehicle, as discussed in the various implementations of the present disclosure, the pitch orientation of the vehicle is continually sensed and a correcting torque is applied. In various embodiments, there are two primary means of applying such a correcting torque, either (<NUM>) via the wheel motors themselves or (<NUM>) via the motion of a counterweight moving forward and backward in the longitudinal direction of the vehicle.

In the various implementations of the present disclosure detailed herein, dynamic stabilization is achieved via both the motor torque and a counterweight. However, in a deviation from previously developed stabilization systems, such as that described in <CIT>, rather than using a separate counterweight, in the disclosed implementations, the wheels move relative to the body of the vehicle as a whole, such that the body and chassis act as the counterweight. This allows significantly more control authority, as over half of the vehicle mass can be used for the level arm. One artifact of this approach is that the propulsion force causing rotation of the wheel is applied at the center of the wheel, instead of using a rim drive. The so-called hub drive can be driven by a motor integrated into or positioned beside the wheel. Each wheel can be independently controlled. Depending on the various implementations described herein, the wheel to motor mass ratio can be as little as <NUM>/<NUM> of the total vehicle mass, allowing <NUM>/<NUM> of the mass for control.

In accordance with various aspects of the present disclosure, navigation may be accomplished via a "following" mode in which the vehicle (or robot) is virtually linked to a human or another vehicle and executes a "leader" path. Alternatively, navigation may be accomplished via an autonomous mode in which the vehicle travels between preset waypoints. In both cases, active obstacle detection and avoidance is implemented. Both indoor and outdoor operation can be achieved using visual SLAM (simultaneous localization and mapping) technologies and approaches.

Disclosed herein are various embodiments of a robotic follower and/or carrier vehicle and its components. <FIG> illustrates a perspective view of various components a vehicle <NUM>, according to aspects of the inventive concepts. The robotic vehicle <NUM> can be a robotic follower vehicle that is configured with a storage or carrier compartment. The robotic vehicle can identify a leader, e.g., a human, and then follow the leader.

<FIG> illustrates a rear view of the various components of the vehicle <NUM>, according to aspects of the inventive concepts. Referring to <FIG> and <FIG>, the vehicle <NUM> includes a chassis <NUM>. The chassis <NUM> is the structural frame of the vehicle <NUM>, and supports a body <NUM> that forms a protective shell of the vehicle <NUM>.

In some implementations, the vehicle <NUM> further includes at least one wheel carriage <NUM>, as best shown in <FIG>. The wheel carriage <NUM> is moveably coupled to, and longitudinally displaceable relative to the chassis, as will be discussed in further detail below. The wheel carriage <NUM> is configured such that a wheel, e.g., wheel <NUM>, and its corresponding motor <NUM> may be rotatably coupled thereto. As will be described in further detail below with reference to <FIG> and <FIG>, a wheel carriage is coupled to a linear actuator system which allows the wheel carriage to translate back and forth in the longitudinal direction of the chassis, in order to control a pitch and balancing of the chassis <NUM>. For example, as the wheel carriage is translated by the linear actuator system, the corresponding wheel, which is mounted on the wheel carriage, translates along with the wheel carriage relative to the chassis. This causes a relative translation of the chassis <NUM> in the opposite direction, thereby acting as a counterweight, and adjusting the pitch and center of gravity of the chassis. The present disclosure thus provides the advantage of using the actual body of the vehicle <NUM> to act as a counterweight and maintain a near-zero pitch angle by moving the chassis <NUM> relative to the wheels, e.g., wheel <NUM> and/or wheel <NUM>.

In an embodiment, the vehicle includes a first wheel <NUM> and a second wheel <NUM>, disposed on opposite sides of the vehicle body <NUM>. Those skilled in the art having the benefit of this disclosure will appreciate that in elements described using the term "second" are substantially duplicates of mirrors of items described using the term "first," each of the "second" elements having connections and functioning in substantially the same manner as the corresponding elements "first" elements.

As discussed above, the first wheel <NUM> may be rotationally mounted on a first wheel carriage <NUM> and coupled to the chassis <NUM> through the first wheel carriage <NUM>. Similarly, the second wheel <NUM> may be rotationally mounted on a second wheel carriage <NUM> and coupled to the chassis <NUM> through the second wheel carriage <NUM>. The first and second wheels <NUM> and <NUM> each include a geometric center and a diameter. The size of the wheels can vary depending on the needs for torque, ground clearance, and the desired location of the center of gravity relative to the center of rotation of the vehicle <NUM>. Perferably, however, the first and second wheels are the same size. In some aspects, the size of the vehicle <NUM> may vary between <NUM> inches to <NUM> inches (<NUM> and <NUM>) tall, with similar widths. In the illustrated figures, the diameters of the wheels <NUM> and <NUM> are shown to be smaller than the length and height of the vehicle <NUM>. However the various implementations of the present disclosure are not limited thereto. In some instances the opposite could apply. That is, the diameter of the wheels <NUM> and <NUM> may be larger than the length and height of the vehicle <NUM>.

In some implementations, the diameter of the wheels <NUM> and <NUM> can be between <NUM> and <NUM> inches (<NUM> and <NUM>) inclusive. In certain implementations, the diameter of the wheels <NUM> and <NUM> is at least <NUM>% of the height, length, width, and/or diameter of the chassis <NUM> and/or vehicle <NUM>. Each wheel <NUM> and <NUM> may also include a rim substantially defining an outer surface of the wheel <NUM> and <NUM>. A tire may be disposed around each rim. The tires may be removably mounted to the respective rims <NUM>, such that each tire rotates with its rim. The tire may be made from a rubber, polymer, or any other suitable material. The tires may provide frictional contact between the wheel <NUM> and <NUM> and a ground surface to enhance the performance of the vehicle <NUM>.

<FIG> illustrates another perspective view of various components of a linear actuator system of the vehicle <NUM>, according to aspects of the inventive concepts. As illustrated in <FIG>, the vehicle <NUM> may further include a first linear actuator system <NUM>. The first linear actuator system <NUM> may be coupled to the first wheel carriage <NUM>, and adapted to longitudinally displace the first wheel carriage <NUM>, including wheel <NUM>, relative to the chassis <NUM>.

The vehicle <NUM> may further include a second linear actuator system <NUM>, the structure and function of which is similar to that of the first linear actuator system <NUM>. That is, the second linear actuator system <NUM> may be coupled to the second wheel carriage <NUM> at a side opposite to the first linear actuator system <NUM>. For example, the first linear actuator system <NUM> may be positioned at a left side of the vehicle <NUM> whilst the second linear actuator system <NUM> may be positioned at a right side of the vehicle <NUM>, or vice versa. The second linear actuator system <NUM> may similarly be configured to longitudinally displace the second wheel carriage <NUM> relative to the chassis <NUM>.

An axle <NUM> couples the first linear actuator system <NUM> to the second linear actuator system <NUM>. Similar to the first and second wheels <NUM>, <NUM>, in the case of the first and second actuator systems, where described using the term "second", each of the "second" elements connects, and functions, in substantially the same manner as the termed "first" element.

In some implementations, a third motor <NUM> may be coupled to at least one of the first and second linear actuator systems <NUM> and <NUM> to drive the first and second linear actuator systems <NUM> and <NUM>. In some implementations, each of the first and second linear actuator systems <NUM> and <NUM> may include first and second pulleys <NUM> and <NUM>. The first and second linear actuator systems <NUM> and <NUM> may each further include at least one rail coupled to the chassis <NUM> along the longitudinal direction thereof. In some implementations, the at least one rail includes upper and lower rails <NUM> and <NUM>, each coupled to the chassis <NUM>. Each of the upper and lower rails <NUM> and <NUM> includes longitudinal slots extending therethrough, where the respective first and second wheel carriages <NUM> and <NUM> are translated through rotation of the first and second pulleys <NUM> and <NUM>. The first and second wheel carriages <NUM> and <NUM> may each include one or more edge wheels coupled into the rails to facilitate movement of the wheel carriages <NUM> and <NUM> back and forth along the rails with reduced friction. In some other implementations, the first and second linear actuator systems include only one rail on each side of the chassis.

The first and second linear actuator systems <NUM> and <NUM> each further include respective belts <NUM> and <NUM> disposed along outer circumferences of the first and second pulleys <NUM> and <NUM>. In some aspects, the belts <NUM> and <NUM> couple the first and second pulleys <NUM> and <NUM> to each other. The belts <NUM> and <NUM> are configured to transmit power from the third motor <NUM> to longitudinally displace the respective first and second wheel carriages <NUM> and <NUM> relative to the chassis <NUM>.

In accordance with some implementations, the belts <NUM> and <NUM> may be removably attached to the outer circumference of the each of the pulleys <NUM> and <NUM>, such that a rotation of pulleys <NUM> and <NUM> caused by rotational energy delivered from the third motor results in motion of the belt. The belts <NUM> and <NUM> may be formed of a metal, metal alloy, ceramic, polymer, rubber, composite material or any other suitable material. In some implementations, a chains may be used instead of the belts <NUM> and <NUM>, and a cogwheels may be used instead of the pulleys <NUM> and <NUM>. The first and second wheel carriages <NUM> and <NUM> are each coupled to a respective belt <NUM>, <NUM> such that motion of the belts <NUM>, <NUM> causes a corresponding motion of each of the first and second wheel carriages <NUM> and <NUM> relative to the chassis <NUM>, in the longitudinal direction. As will be described below in more detail, motion of the first and second wheel carriages <NUM> and <NUM> causes the respective wheel assemblies, including the motors <NUM> and <NUM>, to translate back and forth in the longitudinal direction relative to the rest of the vehicle <NUM>. The effect of this is to translate the chassis <NUM> (the body) in the opposite direction to which the wheel carriages <NUM> and <NUM> with their respective wheels <NUM> and <NUM> are translated.

In operation, the first and second pulleys <NUM> and <NUM> are driven by a drive pulley system <NUM> which is connected directly to the third motor <NUM> via a drive belt <NUM>. Rotational energy of the motor <NUM> is transferred from a drive pulley <NUM> to a drive pulley <NUM> of the drive pulley system <NUM> through the belt <NUM> of the drive pulley system <NUM>. The drive pulley <NUM> of the drive pulley system <NUM> then transfers rotational energy from the belt <NUM> to each of the pulleys <NUM> and <NUM> of the first and second linear actuator systems <NUM> and <NUM>.

<FIG> is a side view illustrating the linear actuator system and various components of a wheel assembly including a hub motor according to an implementation of the present disclosure. As illustrated in <FIG>, the vehicle <NUM> may further include the first motor <NUM> integrated into the first wheel <NUM>, and coupled to the first wheel carriage <NUM>. The motor <NUM> may be coupled to the first wheel carriage <NUM> through a first shaft <NUM>, and configured to provide drive energy to the first wheel <NUM>. The motor <NUM> is powered by receiving electrical energy from a battery <NUM> (shown in <FIG>), or fuel cell. The battery <NUM> may be positioned centrally, on a bottom surface of the chassis <NUM>. In some embodiments, the motor <NUM> is a hub motor which is mounted directly in the center of the first wheel <NUM>. To this effect, the motor <NUM> is configured with a stator <NUM> including a series of stationary coils disposed thereon. The stator can couple directly to the first wheel carriage <NUM>, through which electric current is provided to the coils. The motor <NUM> may further include a rotor <NUM> which is integrated into the first wheel <NUM>. The rotor <NUM> may be configured to include a series of magnets, and is rotationally mounted about the stator <NUM> so as to rotate around the stator <NUM> as applied current from the battery <NUM> generates an electromagnetic field. The first wheel <NUM>, being integrally attached to the spinning rotor <NUM>, rotates along with the spinning rotor <NUM>.

The vehicle <NUM> may further include a second motor <NUM> integrated into the second wheel <NUM>, and coupled to the second wheel carriage <NUM>, as best shown in <FIG>. Similar to the first motor <NUM>, the second motor <NUM> may be attached to the second wheel carriage <NUM> through a second shaft <NUM>, and configured to provide drive energy to the second wheel <NUM>. The second motor <NUM> is also powered by receiving electrical energy from the battery <NUM> or fuel-cell. As discussed above with respect to the first motor <NUM>, the second motor <NUM> may similarly be a hub motor which is mounted directly in the center of the second wheel <NUM>. To this effect, the second motor <NUM> may similarly be configured with a stator <NUM> and a spinning rotor <NUM> which are structured and which function similar to the stator <NUM> and rotor <NUM> of the first motor <NUM>. Similar to the first and second wheels, in the case of the first and second motors, where described using the term "second," each of the "second" elements connects, and functions, in substantially the same manner as the termed "first" element.

In some implementations, the hub motors <NUM> and <NUM> are independent from one another and may be commanded via unique channels of one or more motor controllers <NUM> contained in an autonomy and navigation computer <NUM>. The vehicle <NUM> receives commands from the autonomy and navigation computer <NUM> and translates those commands into forward motion of the wheels <NUM> and <NUM> via the respective hub motors <NUM> and <NUM>. The independence of the motors <NUM> and <NUM> allows a variety of turning modes. For example, the vehicle <NUM> may turn in place by running the motors <NUM> and <NUM> in at different speeds or in different directions. Alternatively, the vehicle <NUM> may turn sharp corners by keeping one motor off while the other is active, for a turning radius equivalent to the width of the wheel track. In some aspects, the vehicle <NUM> may make tight to broad turns by commanding the one of the two wheels, which paves the outer trajectory of the turn, at a faster rate than the wheel paving the inner trajectory. This maneuverability can be coupled to a pitch controller <NUM> to provide stable operation, as described in further detail below.

<FIG> is a view illustrating a maximum rearward position of the wheel and carriage relative to the chassis of the vehicle, and <FIG> is a view illustrating a maximum forward position of the wheel and carriage relative to the chassis of the vehicle according to an implementation of the present disclosure. In accordance with some implementations, each of the linear actuator systems <NUM> and <NUM> allow the respective wheel assemblies including the hub motors <NUM> and <NUM> to translate back and forth in the longitudinal direction relative to the rest of the vehicle <NUM>. The effect of this is to translate the chassis <NUM> (and the body <NUM>) in the opposite direction to which the wheel carriages <NUM> and <NUM> with their respective wheels <NUM> and <NUM> are translated. In some aspects, each of the first and second linear actuator systems displace the respective first and second wheel carriages relative to the chassis at speeds of up to <NUM>/sec. Thus, the present disclosure provides the advantage of having available the weight of the entire chassis <NUM> of the vehicle <NUM> to act as a counterweight to balance and dynamically stabilize the vehicle <NUM> and maintain the vertical orientation of the laterally mounted vehicle <NUM>.

<FIG> illustrates an upper perspective view of various components of a linear actuator system of the vehicle according to a second embodiment of the present disclosure. <FIG> illustrates a side view of the various components of a linear actuator system of the vehicle according to the second implementation of the present disclosure. As illustrated in <FIG>, the vehicle <NUM> may include first and second linear actuator systems <NUM> and <NUM>, in place of first and second linear actuator systems <NUM> and <NUM>. The first and second linear actuator systems <NUM> and <NUM> include a third motor <NUM> instead of the third motor <NUM>. In some implementations, the third motor <NUM> may be coupled at a first end to at least one of the first and second linear actuator systems <NUM> and <NUM> to drive the first and second linear actuator systems <NUM> and <NUM>. The third motor <NUM> may be mounted on a second end thereof to the chassis <NUM>. Similar to the configuration of the first and second linear actuator systems <NUM> and <NUM>, each of the first and second linear actuator systems <NUM> and <NUM> may include first and second pulleys <NUM> and <NUM>, and upper and lower rails <NUM> and <NUM>, each coupled to the chassis <NUM>. The third motor <NUM> is configured to be mounted to the chassis <NUM> at a position between the first and second pulleys <NUM> and <NUM>. Each of the upper and lower rails <NUM> and <NUM> include longitudinal slots extending therethrough, along which the respective first wheel carriage (not shown) and second wheel carriage <NUM> are translated through rotation of the first and second pulleys <NUM> and <NUM>. The first and second linear actuator systems <NUM> and <NUM> may each further include respective belts <NUM> and <NUM> disposed along outer circumferences of the first and second pulleys <NUM> and <NUM>.

In some aspects, the belts <NUM> and <NUM> couple the first and second pulleys <NUM> and <NUM> to each other. An axle similar to the axle <NUM> may couple the first pulleys <NUM> of the first and second linear actuator systems <NUM> and <NUM> to each other, so that rotational energy of the third motor <NUM> may be transmitted to both the first pulleys <NUM> of the first and second linear actuator systems <NUM> and <NUM>. The belts <NUM> and <NUM> are configured to transmit power from the third motor <NUM> to longitudinally displace the respective first wheel carriage (not shown) and second wheel carriage <NUM> relative to the chassis <NUM>. In some implementations, the second linear actuator system <NUM> may include a separate fourth motor <NUM> to drive the second linear actuator system <NUM> independently of the first linear actuator system <NUM>. The fourth motor <NUM> may function similarly to the any of the aforementioned third motors <NUM> and <NUM>, and may be coupled to an opposite side of the chassis <NUM> to that of the third motor <NUM>. In these implementations, the belt <NUM> is configured to transmit power from the third motor <NUM> to longitudinally displace the first wheel carriage (not shown in <FIG>) relative to the chassis <NUM>. The belt <NUM> is configured to transmit power from the fourth motor <NUM> to longitudinally displace the second wheel carriage <NUM> relative to the chassis <NUM>.

In accordance with some implementations, the belts <NUM> and <NUM> may be removably attached to the outer circumference of the each of the pulleys <NUM> and <NUM>. A rotation of pulleys <NUM> and <NUM> caused by rotational energy delivered from the third and/or fourth motors <NUM> and/or <NUM> results in motion of the belts <NUM> and/or <NUM>. In some implementations, the third and fourth motors <NUM> and <NUM> may be synchronized to provide synchronized motion of the first and second linear actuator systems <NUM> and <NUM>.

As will be described above with respect to the <FIG>, motion of the first wheel carriage (not shown) and the second wheel carriage <NUM> causes the respective wheel assemblies including the motors <NUM> and <NUM> to translate back and forth in the longitudinal direction relative to the rest of the vehicle <NUM>. The effect of this is to translate the chassis <NUM> (and body <NUM>) in the opposite direction to which the first wheel carriage (not shown) and the second wheel carriage <NUM> with their respective wheels <NUM> and <NUM> are translated. In the case of the first and second carriages, where described using the term "second," each of these "second" elements connects, and functions, in substantially the same manner as the termed "first" element.

<FIG> illustrates a perspective view of various components of a linear actuator system of the vehicle according to a third embodiment of the present disclosure. <FIG> illustrates a side view of the various components of a linear actuator system of the vehicle according to the third implementation of the present disclosure.

As illustrated in <FIG>, the vehicle <NUM> may include first and second linear actuators <NUM> and <NUM>, in place of first and second linear actuator systems <NUM> and <NUM>. The vehicle <NUM> may include a third motor <NUM> instead of the third motor <NUM>. In some implementations, the third motor <NUM> may be coupled at a first end to at least one of the first and second linear actuator systems <NUM> and <NUM> to drive at least one the first and second linear actuator systems <NUM> and <NUM>. The third motor <NUM> may be mounted at a second end thereof to the chassis <NUM>. Similar to the configuration of the first and second linear actuator systems <NUM> and <NUM>, each of the first and second linear actuator systems <NUM> and <NUM> may include first and second pulleys <NUM> and <NUM>, and upper and lower rails <NUM> and <NUM>, each coupled to the chassis <NUM>. The third motor <NUM> is configured to be mounted to the chassis <NUM> and directly connected to at least one of the second pulleys <NUM>. Each of the upper and lower rails <NUM> and <NUM> include longitudinal slots extending therethrough, along which the respective first wheel carriage (not shown) and second wheel carriage <NUM> are translated through rotation of the first and second pulleys <NUM> and <NUM>. The first and second linear actuator systems <NUM> and <NUM> may each further include respective belts <NUM> and <NUM> disposed along outer circumferences of the first and second pulleys <NUM> and <NUM>.

In some aspects, the belts <NUM> and <NUM> couple the first and second pulleys <NUM> and <NUM> to each other. An axle similar to the axle <NUM> may couple the first pulleys <NUM> of the first and second linear actuator systems <NUM> and <NUM> to each other, so that rotational energy of the third motor <NUM> may be transmitted to rotate both the second pulleys <NUM> of the first and second linear actuator systems <NUM> and <NUM>. The belts <NUM> and/or <NUM> are configured to transmit power from the third motor <NUM> to longitudinally displace the respective first wheel carriage (not shown) and/or second wheel carriage <NUM> relative to the chassis <NUM>. In some implementations, the first linear actuator system <NUM> may include a separate fourth motor (not shown) to drive the first linear actuator system <NUM> independently of the second linear actuator system <NUM>. The fourth motor (not shown) may function similarly to the any of the aforementioned third motors <NUM> and <NUM>. In these implementations, the belt <NUM> is configured to transmit power from the third motor <NUM> to longitudinally displace the second wheel carriage <NUM> relative to the chassis <NUM>. The belt <NUM> is configured to transmit power from the fourth motor (not shown) to longitudinally displace the first wheel (not shown) relative to the chassis <NUM>.

In accordance with some implementations, the belts <NUM> and <NUM> may be removably attached to the outer circumference of the each of the pulleys <NUM> and <NUM>, such that a rotation of pulleys <NUM> and <NUM> caused by rotational energy delivered from the third and/or fourth motors results in motion of the belts <NUM> and/or <NUM>. In some implementations, the third and fourth motors may be synchronized to provide synchronized motion of the first and second linear actuator systems <NUM> and <NUM>.

As will be described above with respect to the <FIG>, motion of the first wheel carriage (not shown) and the second wheel carriage <NUM> causes the respective wheel assemblies including the motors <NUM> and <NUM> to translate back and forth in the longitudinal direction relative to the rest of the vehicle <NUM>. The effect of this is to translate the chassis <NUM> (the body) in the opposite direction to which the first wheel carriage (not shown) and the second wheel carriage <NUM> with their respective wheels <NUM> and <NUM> are translated. In the case of the first and second carriages, where described using the term "second," each of these "second" elements connects, and functions, in substantially the same manner as the termed "first" element.

In accordance with some other implementations, the first and second linear actuator systems <NUM>, <NUM>, may each be selected from the group consisting of a ball screw, a roller screw, a voice coil, a rack and pinion, a hydraulic cylinder, and a pneumatic cylinder.

Referring back to <FIG>, during normal operation, the vehicle <NUM> experiences pitch moments around the lateral axis. These pitch moments are either gravity induced due to the vehicle <NUM> being not precisely balanced, or dynamically-induced from acceleration or braking. In the case of balancing, the laterally-mounted vehicle <NUM> has a very short static stability margin, which is the longitudinal direction of the vehicle <NUM>, over which the center of gravity can move without causing the vehicle <NUM> to pitch forward or backward in the longitudinal direction. The length of the stability margin is equivalent to the length of the contact patch of the tires off the wheels <NUM> and <NUM>. In order to avoid precise positioning of the center of gravity of the chassis <NUM> of the vehicle <NUM>, the pitch of the chassis <NUM> is corrected using at least one of the first and second linear actuator systems <NUM> and <NUM>. Each of the linear actuator systems <NUM> and <NUM> adjusts the center of gravity of the chassis <NUM> automatically upon sensing an imbalance of the vehicle <NUM>. This provides the advantage of allowing a variety of items with flexible weight distributions to be located within the cargo volume <NUM>.

In accordance with some implementations, controlled adjustments of the linear actuator systems <NUM> and <NUM> allow the vehicle <NUM> to automatically maintain a near-zero pitch angle. Pitch angle of the chassis <NUM> or vehicle <NUM> relative to the horizontal is continually sensed using a pitch sensor <NUM>. As used herein, horizontal refers to a plane which is normal or perpendicular to the gravitational pull of the earth. In some aspects, the pitch sensor <NUM> may be either an inclinometer or an inertial measurement unit positioned on the chassis <NUM>. The economy and navigation computer <NUM> may then use the sensed data to provide a correcting torque around the center of rotation of the chassis <NUM> or the vehicle <NUM>, in the plane of the wheels <NUM> and <NUM>, to maintain the pitch angle of the chassis <NUM> to be within plus or minus [<NUM>] degrees of the horizontal to allow stable operation of the vehicle <NUM>. The effect of this is to maintain the pitch of the chassis <NUM> or vehicle <NUM> at a near zero pitch angle. The correcting torque is thus generated by the motion of the chassis <NUM> back and forth relative to the carriages <NUM> and <NUM> and respective wheels <NUM> and <NUM>. For a given mass of the vehicle <NUM> (including any payload in the cargo volume <NUM>), an increase in the offset from the center of rotation of the vehicle <NUM> generates a proportional increase in torque to counter the pitch moments experienced during normal operation of the vehicle <NUM>, around the lateral axis thereof.

The first and second linear actuator systems are continuously operated during forward and backward motion and turning motion of the vehicle <NUM>, i.e., during normal operation thereof. In some aspects, normal operation consists of multiple starts and stop and turns, and the resulting decelerations and accelerations generate the pitching moments of the vehicle <NUM> that must be countered to maintain vehicle stability. In addition, the vehicle <NUM> must be capable of ascending and descending grades, e.g. changes in slope on level of a terrain on which the vehicle <NUM> travels. Such changes in terrain from level ground induce changes in the gravity vector of the vehicle <NUM>. The present disclosure provides the advantage that due to continuous operation of the linear actuator systems <NUM> and <NUM>, the vehicle <NUM> is capable of accommodating and riding over inclines and descents of up to, and in some implementations, more than <NUM>°, via the continuously operating sensor and dynamic stability correction.

In some aspects, the center of gravity (Cg) of the vehicle <NUM> could be located either above or below the center of rotation (Cr) thereof. If the Cg is located below the Cr, then the vehicle <NUM> will be dynamically stable, and any disruption will cause the vehicle <NUM> to eventually return to its undisturbed state. However, if the Cg is located above the Cr, during regular operation including acceleration and braking, then the vehicle <NUM> is dynamically unstable, and a disturbance would cause the vehicle <NUM> to continue pitching forward or backward, depending on the disturbance. The present disclosure provides a solution to control the instability of the vehicle caused by the continuous pitching forward or backwards when the Cg is located above the Cr. The aforementioned instability issue can may be controlled according to various implementations of the present disclosure via active control achieved translation of the chassis <NUM> forward and backwards using the linear actuator systems <NUM> and <NUM>.

In some implementations, operation of the two linear actuator systems <NUM> and <NUM> is controlled through use of at least one linear actuator controller <NUM>. For example, motion of the two linear actuator systems <NUM> and <NUM> may be synchronized. However, the configuration of the present disclosure is not limited thereto. In other implementations, the motion of the two linear actuator systems <NUM> and <NUM> may be independent, i.e., decoupled, depending on a desired motion of the vehicle <NUM>. Decoupled motion may be advantageous if one of the wheels <NUM>, <NUM> were to go over a bump or small rise, while the other stayed on level ground. Decoupled motion may also potentially be necessary and advantageous in high-speed turning operations.

<FIG> is an illustration of an electrical block diagram of a control system of the vehicle <NUM> in accordance with an implementation of the present disclosure. The vehicle <NUM> includes one or more sensors, as best shown in <FIG>. In some aspects, the one or more sensors may include two ultrasonic sensors for vehicle autonomy. The one or more sensors may include the pitch sensor <NUM> for sensing the pitch of the vehicle <NUM> and/or chassis <NUM>. The one or more sensors may also include an accelerometer <NUM> for sensing an acceleration of the vehicle <NUM> and/or chassis <NUM>. The one or more sensors may also include a speed sensor <NUM> for sensing a speed of the vehicle <NUM> and/or chassis <NUM>. One or more of the sensors <NUM>, <NUM>, and <NUM> may be disposed and/or secured on an outer surface of the chassis <NUM>. The computer <NUM> may further include a linear actuator controller <NUM>, a motor controller <NUM>, a pitch controller <NUM> and a memory <NUM> in electronic communication with at least one of the sensors <NUM>, <NUM>, and <NUM>. In some aspects, the computer <NUM> may include a proportional-integral-derivative controller (PID controller) or PID-based controller which applies a control loop feedback mechanism to continuously modulate control of the orientation or pitch of the chassis <NUM> of the vehicle <NUM>. In other aspects, the pitch controller may include the PID controller to continuously modulate and correct the pitch angle of the chassis <NUM> and maintain stability of the vehicle <NUM>.

In accordance with some implementations of the present disclosure, a method for dynamically stabilizing a two-wheeled vehicle <NUM> includes measuring, by the at least one sensor <NUM>, <NUM>, and <NUM>, disposed on the chassis <NUM>, a pitch of the chassis <NUM> relative to the horizontal during operation of the vehicle <NUM>, and outputting a pitch signal based thereon. The method further includes controlling, by the pitch controller <NUM>, responsive to pitch signal output of the at least one sensor <NUM>, <NUM>, and <NUM>, at least one of the first and second linear actuator systems <NUM> and <NUM> to displace at least one of the first and second wheel carriages <NUM> and <NUM> longitudinally relative to the chassis <NUM> to control chassis orientation relative to the horizontal in various moving and non-moving states, e.g., "sitting.

The one or more sensors <NUM>, <NUM>, and <NUM> determine and output a measurement of a state of the vehicle <NUM> and/or chassis <NUM>. The determination is sent to the memory <NUM> and controller <NUM>, which orders an operation of at least one of the third motor <NUM> which powers the first and second linear actuator systems <NUM> and <NUM>. For example, the pitch sensor <NUM> determines a pitch of the vehicle <NUM> and/or chassis <NUM> and outputs the measured pitch to the memory <NUM> and controller <NUM>, which commands an operation of the third motor <NUM>. In this manner the vehicle <NUM> can determine, by controller is <NUM>, <NUM>, and <NUM> and based on sensors <NUM>, <NUM>, and <NUM> data, an orientation, acceleration or speed of the vehicle <NUM> and/or chassis <NUM>. In some implementations, the sensors <NUM>, <NUM>, and <NUM> can make multiple determinations at different times or continuously to determine a change in orientation, acceleration or speed of the vehicle <NUM> and/or chassis <NUM>, or rate of change in orientation, acceleration or speed of the vehicle <NUM>.

In some embodiments, once the above determination of an orientation, acceleration or speed, or of a change (or rate of change) in the orientation, acceleration or speed, of the vehicle <NUM> and/or chassis <NUM> is made, the controller <NUM> and/or memory <NUM> control the third motor <NUM> to move at least one of the first and second linear actuator systems <NUM>, <NUM> in response to the measured determination. In one aspect, the controller <NUM> and/or memory <NUM> control the third motor <NUM> to move at least one of the first and second linear actuator systems <NUM> and <NUM> to maintain a substantially constant vehicle <NUM> and/or chassis <NUM> orientation about a lateral axis of the vehicle <NUM> and/or chassis <NUM>. Thus, each of the linear actuator systems <NUM> and <NUM> allow the respective wheel assemblies including the hub motors <NUM> and <NUM> to translate back and forth in the longitudinal direction relative to the rest of the vehicle <NUM>. The effect of this is to translate the chassis <NUM> (and the body <NUM>) in the opposite direction to which the wheel carriages <NUM> and <NUM> with their respective wheels <NUM> and <NUM> are translated. Thus, the present disclosure provides the advantage of having available the weight of the entire chassis <NUM> of the vehicle <NUM> to act as a counterweight to balance and dynamically stabilize the vehicle <NUM> and maintain the vertical orientation of the laterally mounted vehicle <NUM>.

As described above, in accordance with some implementations, controlled adjustments of the linear actuator systems <NUM> and <NUM> allow the vehicle <NUM> to automatically maintain the pitch angle of the chassis <NUM>, e.g., to be within plus or minus two degrees of the horizontal, to allow controlled and/or stable operation of the vehicle <NUM>. The effect of this is to maintain the pitch of the chassis <NUM> or vehicle <NUM> at a near-zero pitch angle, e.g., during steady state movement or constant velocity. The pitch angle of the chassis <NUM> or vehicle <NUM> is continually sensed using the pitch sensor <NUM>, which may be either an inclinometer or an inertial measurement unit. In some aspects, where the economy and navigation computer <NUM> includes a PID controller instead of the pitch controller <NUM>, the PID controller may then use the sensed data to provide a correcting torque around the center of rotation of the chassis <NUM> or the vehicle <NUM>, in the plane of the wheels <NUM> and <NUM>. To this effect, the PID controller continuously calculates an error value as the difference between the desired pitch angle (i.e., near zero pitch angle) and the actual measured pitch based on the instability of the vehicle <NUM>. The PID controller <NUM> then applies a correction factor based on proportional, integral, and derivative terms in order to minimize the difference in value between the desired pitch angle (e.g., near zero) and the sensed or measured pitch angle. Thus, in some implementations, a motion of the chassis <NUM> acting as a counterweight can be determined using a proportional-integral-derivative (PID) controller algorithm.

The correcting torque is applied to maintain the pitch angle of the chassis <NUM> to a near zero pitch angle to allow stable operation of the vehicle <NUM>. The correcting torque is thus generated by the motion of the chassis <NUM> back and forth relative to the carriages <NUM> and <NUM> and respective wheels <NUM> and <NUM>. For a given mass of the vehicle <NUM> (including any payload in the cargo volume <NUM>), an increase in the offset from the center of rotation of the vehicle <NUM> generates a proportional increase in torque to counter the pitch moments experienced during normal operation of the vehicle <NUM>, around the lateral axis thereof.

<FIG> is an isometric view of an embodiment of a vehicle in the form of a mobile carrier <NUM>, in accordance with aspects of the inventive concepts. The mobile carrier <NUM> includes a body <NUM> and a set of wheels <NUM>. In this embodiment, the mobile carrier is a two-wheeled carrier, having a first wheel <NUM> on one side of the carrier body <NUM> and a second wheel <NUM> on an opposite side of the carrier body <NUM>. In various embodiments, the body <NUM> also includes a lid <NUM> that provides access to an internal storage compartment, payload, and/or equipment. In various embodiments, the internal storage compartment can be configured to receive a load, such that the mobile carrier <NUM> is configured to carry the load.

In this embodiment, the carrier <NUM> further includes a user interface <NUM>. In various embodiments, the user interface <NUM> can include one or more input devices and/or sensors configured to enable a user to control operation and functions of the mobile carrier, enable the mobile carrier to perform or cease certain operations or functions based, at least in part, on sensor data, and/or combinations thereof. As examples, the user interface <NUM> can include one or more buttons, touch screens, cameras, range sensors, audio input device (e.g., microphone), audio output devices, light emitting devices, and so on, and various combinations thereof.

<FIG> are front views of the mobile carrier <NUM> of <FIG>. From <FIG>, the two wheels <NUM>, <NUM> are more clearly visible, as is the user interface <NUM>.

<FIG> is a top view of the mobile carrier <NUM> of <FIG>. From this view, the wheels <NUM>, <NUM> are partially visible, because portions of the body <NUM> wrap over and cover a view of the wheels <NUM>, <NUM> from the top. The lid <NUM> is more visible from this viewpoint. In this embodiment, the lid <NUM> includes two grips <NUM>, <NUM> useful for opening the lid <NUM>. In other embodiments, different mechanisms could be provided for opening the lid <NUM>.

<FIG> is a side view of the mobile carrier <NUM> of <FIG> with the wheels <NUM>, <NUM> centered. In <FIG>, a vertical axis "Y" passes through an axis of rotation of the wheels <NUM>, <NUM>. In this view, wheels <NUM>, <NUM> are in a neutral position, i.e., generally centered with the axis Y and a center of mass of the mobile carrier <NUM>. In various embodiments, the neutral position can be a steady state travel position, e.g., wherein the mobile carrier <NUM> is not accelerating or decelerating, and/or an intermediate position achieved while shifting between rearward and forward positions of the wheels <NUM>, <NUM>.

In preferred embodiments, the mobile carrier <NUM> includes a linkage-based shifting assembly (see below) that shifts the body <NUM> (including its chassis) back and forth between a forward position and a rearward position relative to the wheels <NUM>, <NUM>. The linkage-based shifting assembly provides more control over the mobile carrier <NUM> during acceleration and deceleration, i.e., more torque control on the wheels <NUM>, <NUM> in response to the positon of the load with respect to an axis of rotation of the wheels <NUM>, <NUM>. In various embodiments, the wheels <NUM>, <NUM> share a common axis of rotation, but can be independently driven.

<FIG> a side view of the mobile carrier <NUM> of <FIG> with the wheels <NUM>, <NUM> back and the center of mass (and body <NUM>) forward. This orientation of the wheels <NUM>, <NUM> can be a rest or "sitting" position of the carrier <NUM>, e.g., where at least one portion of the body, e.g., a foot, contacts a ground surface in addition to the wheels <NUM>, <NUM>. The body <NUM> can shift slightly forward such that the foot raises off the ground surface and the body can remain shifted forward with respect to the wheels <NUM>, <NUM> for acceleration of the carrier <NUM>. During acceleration, therefore, the axis of rotation of the wheels <NUM>, <NUM> is shifted behind the center of mass of the carrier body <NUM>, which gives more control over torque in the wheels <NUM>, <NUM> during acceleration. The shifting of the wheels from the neutral (or "standing") position to the rearward position is enabled and controlled by the linkage-based shifting assembly discussed herein.

<FIG> a side view of the mobile carrier <NUM> of <FIG> with the wheels <NUM>, <NUM> forward and load (body <NUM>) back. This orientation of the wheels <NUM>, <NUM> with respect to the body <NUM> (and center of mass) can be an orientation used in deceleration of the carrier <NUM>, with the wheels <NUM>, <NUM> shifted forward of the center of mass of the carrier body <NUM>, which gives more control over torque in the wheels <NUM>, <NUM> during deceleration. The shifting of the wheels <NUM>, <NUM> from the rearward, through the neutral position, to the forward position is enabled and controlled by the linkage-based shifting assembly.

<FIG> shown side views of the mobile carrier <NUM> of <FIG> moving from sitting to standing and driving positions (left to right), with appropriate relative shifting of the wheels and body. In <FIG>, the mobile carrier <NUM> is in the starting or sitting position, with the wheels <NUM>, <NUM> rearward with respect to the body <NUM>. This is also an acceleration position, used to transition from the sitting state to a moving state. The carrier body <NUM> shifts with respect to the wheels <NUM>, <NUM> to transition the carrier out of the sitting position and to a standing position for acceleration. The wheels <NUM>, <NUM> remain in this shifted position as the mobile carrier <NUM> accelerates. In <FIG>, the carrier is shown in an acceleration position.

<FIG> shows the carrier <NUM> in a neutral traveling or transition position, which can also be a standing position. The position can be used when the carrier is traveling, e.g., at a substantially constant speed. This position could also be used in acceleration and/or deceleration, but torque control would not be as good as it would be in the positions shown in <FIG>. This position can also be an intermediate position between shifting the body rearward or forward with respect to the wheels <NUM>, <NUM>.

<FIG> shows the carrier <NUM> in a deceleration position, with the wheels <NUM>, <NUM> shifted forward with respect to the axis Y. This position of the wheels <NUM>, <NUM> is advantageous for stopping or slowing.

<FIG> is an isometric view of an embodiment of a linkage-based shifting assembly <NUM> that can form part of the mobile carrier <NUM> of <FIG>. <FIG> is a front view of the linkage-based assembly of <FIG>. And <FIG> a bottom isometric view of the linkage-based shifting assembly of <FIG>.

The assembly <NUM> is particularly useful for enabling and effecting shifting of the carrier body <NUM> with respect to two or more wheels sharing a common access of rotation, such as wheels <NUM>, <NUM>. The assembly <NUM> can be disposed within the carrier body <NUM> and move relative to the carrier body <NUM>.

The assembly <NUM> includes a first swing arm 802a and a second swing arm 802b, disposed on opposite sides of the assembly <NUM>. The arms 802a, 802b are configured to swing relative to a mobile carrier chassis of the carrier body <NUM>. In various embodiments, the arms 802a, 802b are configured to simultaneously swing to move the body <NUM> and its chassis with respect to the center of the wheels <NUM>, <NUM>, which remain co-axial with the axis "X".

At a proximal end of each arm 802a, 802b, is a connection structure 804a, 804b configured to receive the wheels <NUM>, <NUM>. In this embodiment, the connection structure 804a takes the form of an opening configured to receive an axle of the wheel <NUM> and the connection structure 804b takes the form of an opening configured to receive an axle of the wheel <NUM>. The couplings between the wheels <NUM>, <NUM> and their respective arms 802a, 802b enables rotation of the wheels with respect to the arms on the axis X of rotation.

In the present embodiment, intermediate first and second support plates 806a, 806b are stationary relative to the carrier body <NUM>, or its chassis. The support plates 806a, 806b can be orientated substantially parallel to the wheels <NUM>, <NUM>, such as in this embodiment. In this embodiment, each of the first and second support plates 806a, 806b includes a plurality of flanges 805a, 805b, 807a, 807b configured to secure the first and second support plates 806a, 806b to the chassis of carrier body <NUM>.

The arms 802a, 802b are configured to swing parallel to the support plates 806a, 806b. In this embodiment, various linkage components are disposed between the support plates 806a, 806b. This arrangement is configured to provide maximum space for an internal storage compartment (not shown), payload, or equipment of the mobile carrier <NUM>.

A first linkage arm 812a and a second linkage arm 814a extend from the first support plate 806a. The first linkage arm 812a and the second linkage arm 814a are rotatably coupled to the first support plate 806a. And a third linkage arm 812b and a fourth linkage arm 814b extend from the second support plate 806b. The third linkage arm 812b and the fourth linkage arm 814b are rotatably coupled to the second support plate 806b.

A first linkage bar 816a couples between a distal end of the first arm 802a and a distal end of the second arm 802b. The first linkage bar 816a passes through an opening at a bottom end of the first linkage arm 812a to couple to the first arm 802a and passes through an opening at a bottom end of the third linkage arm 812b to couple to the second arm 802b.

A second linkage bar 816b also couples between the distal end of the first arm 802a and the distal end of the second arm 802b. The second linkage bar 816b passes through an opening at a bottom end of the third linkage arm 814a to couple to the first arm 802a and passes through an opening at a bottom end of the fourth linkage arm 814b to couple to the second arm 802b. The first and second linkage bars 816a, 816b extend along axes that are parallel to the axis X of rotation of the wheels <NUM>, <NUM>.

Also at distal ends of the arms 802a, 802b are disposed left and right wheel pulleys 808a, 808b. In this embodiment, the left and right wheel pulleys 808a, 808b are disposed between the first and second linkage bars 816a, 816b. The pulleys 808a, 808b are respectively driven by drive motors 810a, 810b. In various embodiments, motor 810a is coupled to arm 802a and motor 810b is coupled to arm 802b. This configuration allows the motors 810a, 810b to stay stationary with respect to the wheels <NUM>, <NUM>, as each motor 810a, 810b is also attached to its swing arm 802a, 802b.

The pulleys 808a, 808b can be configured to operatively couple to their respective wheels <NUM>, <NUM>. The hubs of wheels <NUM>, <NUM> preferably include, therefore, corresponding pulleys 104a, 104b. In various embodiments, a first belt (not shown) is operatively coupled between pulley 808a and the corresponding pulley 104a of wheel <NUM>. Similarly, a second belt (not shown) is operatively coupled between pulley 808b and the corresponding pulley 104b of wheel <NUM>. As such, motors 810a, 810b are configured to independently drive wheels <NUM>, <NUM> via their respective pulley systems.

A shifting assembly <NUM> is disposed between the arms 802a, 802b and the support plates 806a, 806b. The shifting assembly <NUM> is configured to shift the carrier body <NUM> with respect to the wheels <NUM>, <NUM>.

The shifting assembly <NUM> includes a gear carriage <NUM> having a bottom portion through which the first and second linkage bars 816a, 816b pass. At a bottom portion of the gear carriage <NUM> is a first gear <NUM>, with a second gear <NUM> and a coaxial capstan <NUM> disposed at a top portion of the gear carriage <NUM>. In this embodiment, the gear carriage <NUM> comprises parallel plates between which is disposed the first and second gears <NUM>, <NUM> and capstan <NUM>.

At least one shifter motor <NUM> drives the first gear <NUM> to cause rotational movement of the first gear <NUM>. The first gear <NUM> engages and drives the second gear <NUM> in response to the shifter motor <NUM> actuation. The second gear <NUM> is coupled to or includes the capstan <NUM>. Rotation of the second gear <NUM> causes a corresponding rotation of the capstan <NUM>.

An encoder <NUM> is operatively coupled to the second gear <NUM> and capstan <NUM> and measures an angle of the second gear <NUM>. The capstan <NUM> winds a steel rope (not shown) that is fixed to the mobile chassis (or carrier body <NUM>) at both ends. Rotation of the capstan <NUM> via rotation of the second gear <NUM>, which is engaged and rotated by the fist gear <NUM>, provides the shifting action of the carrier body <NUM> with respect to the wheels <NUM>, <NUM>, by climbing the linkage assembly <NUM> with the drive motors 810a, 810b, and wheels <NUM>, <NUM> from end-to-end of the chassis, wherein the support plates 806a, 806b attached to the chassis remain relatively stationary.

Therefore, in this embodiment, the shifter motor <NUM> couples to the first gear <NUM> to selectively shift the assembly <NUM> forward and rearward. In shifting the assembly <NUM>, the mobile carrier body <NUM> are selectively shifted forward and rearward in a controlled manner with respect to the wheels <NUM>, <NUM> and axis X of wheel rotation.

<FIG> a side view of another embodiment of a wheel shifting assembly <NUM>, in accordance with aspects of the inventive concepts. The embodiments, of <FIG> are specific types of wheel shifting assemblies. In various other embodiments, the shifting assembly <NUM> can take any form that enable shifting of the carrier body and/or chassis to shift forward and/or rearward with respect to wheels <NUM>, <NUM>. Such shifting can be used to shift wheels <NUM>, <NUM> forward and rearward, e.g., in one or more tracks <NUM>, whether straight or curved. Such shifting shifts the center of mass forward and rearward with respect to the wheels <NUM>, <NUM>, thereby improving control of the torque applied to the wheels for acceleration and deceleration of the mobile carrier <NUM>.

The various implementations of the present disclosure provide advantages over prior art in that the entire vehicle chassis mass, i.e., the entire vehicle mass, minus the hub motors and wheels, serves as the counterweight for stabilizing the vehicle <NUM>. This provides a sizeable amount of torque than previously achievable, and thus allows larger acceleration and deceleration, and accordingly shorter braking distances and quicker responsiveness. In addition, the increased torque allows better performance when the vehicle ascends and descends terrain of varying slope.

Claim 1:
A linkage-based shifting apparatus, comprising:
first and second arms (802a, 802b);
a first wheel (<NUM>) rotatably coupled to a proximal end of the first arm (802a);
a second wheel (<NUM>) rotatably coupled to a proximal end of the second arm (802b);
a shifting assembly (<NUM>) configured to couple to a chassis, the shifting assembly (<NUM>) operatively coupled to the first and second arms(802a, 802b) to cause a relative shifting motion between the chassis and the first and second wheels (<NUM>, <NUM>);
a shifter motor (<NUM>) configured to drive a capstan (<NUM>) configured to couple to the chassis via a belt or rope; and
a gear coupling the shifter motor to the capstan (<NUM>), including
a first gear (<NUM>) driven by the shifter motor; and
a second gear (<NUM>) driven by the first gear, wherein the second gear is configured to rotate the capstan (<NUM>).