Adjustable displacement differential drive system

Abstract

An adjustable displacement differential (ADD) drive unit is disclosed. The ADD drive unit comprises a first drive wheel connected to a first pivot and having a vertical axis laterally offset from the traction point of the first drive wheel. The ADD drive unit comprises a second drive wheel connected to a second pivot and having a vertical axis laterally offset from the traction point of the second drive wheel. The ADD drive unit comprises differential steering, which occurs when the rotational speed of the first drive wheel differs from the rotational speed of the second drive wheel. The ADD drive unit comprises an adjustable steering assembly, which allows adjustment of the orientation of the first drive wheel relative to the second drive wheel, and provides additional drive modes including Ackermann steering, steerable lateral movement, and steerable rotation around a selected vertical axis such as the center of the machine.

Description

Technical Field

[0001] Reference to Related Applications This application claims the benefit and priority of U.S. Provisional Application No. 63 / 458,950, filed on April 13, 2023, the contents of which are hereby incorporated by reference in their entirety.

Background Art

[0002] Conventional robotic control machines typically utilize one of two approaches to handle driving, towing, and steering for moving loads. One approach involves a platform-based system, and the second approach typically involves an "A-frame" system with two forks.

[0003] Platform systems typically feature two wheels, each mounted on either side of the machine. Driving both wheels in the same direction causes the machine to move forward or backward; driving one wheel faster than the other causes the machine to turn. Furthermore, driving the wheels in opposite directions at the same speed allows the machine to rotate in place. This driving and steering method is commonly called a differential, and while other variations exist, this simplest configuration is the most common. Generally, to move objects such as pallets, a platform machine moves under a fixed platform, raising its deck to lift the pallet from the platform. Once the machine leaves the fixed platform, it typically lowers its deck to a more stable height, transporting the object to another fixed platform. While these platform machines can rotate around a central axis with a load on them, allowing for operation in narrow aisles, they also have drawbacks. For example, the drive wheels provide lateral stability, but additional stabilizing wheels are needed for longitudinal stability, which can cause the machine to sway back and forth during acceleration, deceleration, or when traveling on uneven surfaces. Furthermore, conventionally, pallets have been moved using machines that lift them off the floor and return them to the floor upon arrival at the next destination. Therefore, to utilize this platform system, facilities need to design the system and incorporate additional infrastructure so that the platform system can move beneath the pallets and lift / place them onto a fixed platform.

[0004] An A-frame system typically has two forks with small wheels, allowing the forks and wheels to enter the pallet cavity. The forks can lift and transport the pallet from the floor and then lower it to any floor position. The wheels of these forks are usually non-steering due to height and load limitations and are always aligned with the direction of each fork. The drive unit of an A-frame system is generally housed within a structure (i.e., the "A-frame") adjacent to where the forks support the pallet. A typical drive unit includes steerable drive wheels with two precisely controlled axes of motion: one for traction to move the system and the other for steering to change the direction of travel. A-frame structures are usually built vertically to reduce the overall footprint of the system and thus increase maneuverability. However, this drive unit is generally more complex and expensive than a differential drive unit. For example, the traction unit of an A-frame system requires twice the power of the traction unit of a differential drive system because the traction forces of each differential are combined when moving in one direction. Furthermore, a single-wheel steering drive unit requires an additional drive motor, gear mechanism, and control system to provide its steering function.

[0005] Furthermore, A-frame systems typically have non-steering wheels on the forks and a single steering drive wheel on the A-frame, resulting in several functional limitations for this three-wheeled kinematic system. For example, the system is inherently unstable, especially when turning or running unloaded. To address this stability issue, stabilizing wheels are mounted on either side of the steerable drive wheel, positioned above the drive wheel to prevent it from lifting over uneven ground. In this layout, the system typically "rocks" from side to side due to inertia during movement and uneven ground. This rocking can negatively impact the operation of certain sensors, particularly LiDAR and cameras used for positioning and navigation. In addition, the wobbling during movement makes the system feel typically unstable. Moreover, three-wheeled kinematic systems have limited maneuverability in confined spaces and are unable to move laterally or rotate around their center. Some A-frame systems employ a differential drive system, where the two drive wheels are housed in a rotatable housing, allowing for steering without the need for a separately controlled steering system. However, this differential drive unit still needs to pivot to ensure that both drive wheels are always in contact with the ground, so the same limitations as with a single steerable drive wheel exist, and such an A-frame system is still inherently unstable and has limited maneuverability.

[0006] Therefore, improvements to the drive system are technically necessary. This invention satisfies this need. [Overview of the project] [Problems that the invention aims to solve]

[0007] Generally speaking, this disclosure relates to drive systems in general, and more specifically to adjustable displacement differential drive systems.

[0008] In one or more aspects, the disclosed technology relates to a displacement differential drive unit. In one or more cases, the displacement differential drive unit includes a first drive wheel having a traction point. In one or more cases, the first wheel is connected to a first pivot having a vertical axis laterally offset from the first wheel traction point. In one or more cases, the displacement differential drive unit includes a second drive wheel having a traction point. In one or more cases, the second drive wheel is connected to a second pivot having a vertical axis laterally offset from the second drive wheel's traction point. In one or more cases, the displacement differential drive unit includes a first pulley connected to the first pivot and positioned coaxially with the vertical axis of the first pivot. In one or more cases, the displacement differential drive unit includes a second pulley connected to a second pivot and positioned coaxially with the vertical axis of the second pivot. In one or more cases, the displacement differential drive unit includes a belt that engages and connects the first pulley and the second pulley.

[0009] In one or more aspects, the disclosed technology relates to an adjustable differential drive (ADD) unit. In one or more cases, the ADD unit includes a first drive wheel having a traction point. In one or more cases, the first wheel is connected to a first pivot having a vertical axis laterally offset from the first wheel traction point. In one or more cases, the ADD unit includes a second drive wheel having a traction point. In one or more cases, the second drive wheel is connected to a second pivot having a vertical axis laterally offset from the second drive wheel's traction point. In one or more cases, the ADD unit includes a first pulley connected to the first pivot and positioned coaxially with the vertical axis of the first pivot. In one or more cases, the ADD unit includes a second pulley connected to a second pivot and positioned coaxially with the vertical axis of the second pivot. In one or more cases, the ADD unit includes a third pulley. In one or more cases, the relative position of the third pulley and the first or second pulley is adjustable. In one or more cases, the ADD unit includes a belt that engages with and connects a first pulley, a second pulley, and a third pulley.

[0010] In one or more aspects, the disclosed technology relates to an adjustable differential drive (ADD) unit. In one or more cases, the ADD unit includes a first drive wheel having a traction point. In one or more cases, the first wheel is connected to a first pivot having a vertical axis laterally offset from the first wheel traction point. In one or more cases, the ADD unit includes a second drive wheel having a traction point. In one or more cases, the second drive wheel is connected to a second pivot having a vertical axis laterally offset from the second drive wheel traction point. In one or more cases, the ADD unit includes a first rotary actuator connected to the first pivot and positioned coaxially with the vertical axis of the first pivot. In one or more cases, the ADD unit includes a second rotary actuator connected to a second pivot and positioned coaxially with the vertical axis of the second pivot. In one or more cases, the ADD unit includes a steering assembly connecting the first rotary actuator and the second rotary actuator to orient at least one of the first drive wheel and the second drive wheel to provide Ackermann steering.

[0011] Various additional aspects are described below. These aspects may relate to individual features and combinations of features. It should be understood that both the general description above and the detailed description below are illustrative and descriptive only, and do not limit the broad inventive concepts underlying the embodiments disclosed herein. [Brief explanation of the drawing]

[0012] The following drawings illustrate specific embodiments of the present disclosure and are not intended to limit the scope of the present disclosure. The drawings are not to scale and are intended to be used in conjunction with the descriptions in the following detailed description.

[0013] Figure 1A shows a perspective view of an A-frame type pallet moving device. Figure 1B shows a bottom view of this pallet moving device.

[0014] Figure 2 is a top view showing an example of a displacement-type differential drive system.

[0015] Figure 3A shows an isometric projection of an exemplary adjustable displacement differential drive system. Figure 3B shows an exemplary displacement differential steering assembly of the exemplary adjustable displacement differential drive system. Figure 3C shows a front view of the exemplary adjustable differential drive system. Figure 3D shows a rear view of the exemplary adjustable differential drive system with the exemplary displacement differential steering assembly exposed. Figure 3E shows a top view of the adjustable differential drive system with the exemplary displacement differential steering assembly exposed. Figure 3F shows a perspective view of the exemplary linkage and guide assembly. Figure 3G shows a cross-sectional view of the exemplary tensioner.

[0016] Figures 4A to 4G show various configurations of the displacement differential steering assembly and drive wheels during driving.

[0017] Figures 5A–5G illustrate an exemplary adjustable differential drive system, showing various configurations of the displacement differential steering assembly and drive wheels during operation.

[0018] Figure 6A shows an isometric projection of an adjustable differential drive system that utilizes another example of a displacement differential steering assembly. Figure 6B shows a front view of the adjustable differential drive system that is an example of Figure 6A. Figure 6C is a cross-sectional view of the exemplary displacement differential steering assembly of Figure 6A utilizing a first rotational configuration. Figure 6D is a cross-sectional view of the displacement differential steering assembly of Figure 6A utilizing an exemplary second rotational configuration.

[0019] Figure 7 is a block diagram showing the components of the data processing system. [Modes for carrying out the invention]

[0020] In the following description, prior art features of drive systems that are obvious to those skilled in the art will be omitted or briefly described. Various embodiments will be described in detail with reference to the drawings, where the same reference numerals indicate the same parts and assemblies in multiple drawings. References to various embodiments or examples will not limit the scope of the appended claims. Furthermore, none of the examples described herein are limiting, but merely represent a selection of the many possible embodiments of the appended claims. In addition, certain features described herein can be used in combination with other described features in a variety of possible combinations and permutations.

[0021] Unless otherwise defined herein, all terms are to be interpreted in the broadest and most reasonable way, including the meaning implied by the specification, the meaning understood by those skilled in the art, and / or the definitions found in dictionaries, specialized books, etc. The singular form used in the specification and the appended claims is to be interpreted as including the plural form unless otherwise specified. Furthermore, the terms “equipped with,” “included,” and / or “equipped with,” “included,” as used herein, identify the presence of a described feature, element, and / or component, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0022] Relative terms such as "horizontal," "vertical," "up," "down," "upper part," and "lower part," and their derivatives (e.g., "horizontally," "downward," "upward," etc.) should be interpreted as referring to the direction being described at that time or the direction illustrated in the drawing being discussed. These relative terms are for explanatory convenience and are not intended to require a specific orientation. Terms such as "inward" versus "outward," and "longitudinal" versus "lateral" are interpreted relative to each other, or, where appropriate, relative to an extension axis, rotation axis, or center of rotation. Terms relating to attachments and connections, such as "connected" and "interconnected," unless otherwise specified, refer to relationships in which structures are fixed or attached to each other directly or indirectly through intervening structures, as well as both movable and rigid attachments and connections. The term "operably connected" refers to such attachments, connections, and connections that enable the related structures to operate as intended.

[0023] Throughout this specification, the expressions “one embodiment,” “one embodiment,” or “several embodiments” mean that any particular function, structure, or feature described in relation to an embodiment is included in at least one embodiment of the disclosed subject matter. Therefore, expressions such as “in one embodiment,” “in one embodiment,” or “in several embodiments” appearing in various places in this specification do not necessarily refer to the same embodiment. Furthermore, the particular functions, structures, or features of “one embodiment,” “one embodiment,” or “several embodiments” can be combined in any suitable manner to form additional embodiments by such combination. Embodiments of the disclosed subject matter are intended to include modifications and variations thereof. Terms such as “first,” “second,” and “third” merely identify any of the multiple parts, components, steps, operations, functions, and / or reference points disclosed herein, and similarly do not limit the embodiments of this disclosure to any particular configuration or orientation.

[0024] Furthermore, throughout this specification, various aspects of the invention may be presented in a range format. It should be understood that the description in range format is for convenience and brevity and should not be construed as a limitation lacking flexibility with respect to the scope of the invention. Thus, a description of a range should be considered to specifically disclose not only the individual numerical values within that range but also all possible sub-ranges. For example, a description of a range such as from 1 to 6 should be considered to disclose sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as the individual numerical values within that range (e.g., 1, 2, 2.7, 3, 4, 5, 5.3, 6, and any integers and partial increments therebetween. This applies regardless of the width of the range. In this specification, the term "about" with respect to measurable values such as amounts, durations of time, etc. means including variations within the range of ±20%, ±10%, ±5%, ±1%, ±0.1% of the specified value, and refers to cases where such variations are appropriate).

[0025] As used herein, the term "pulley" refers to any type of pulley (e.g., toothed pulley, flat pulley, etc.), gear, sprocket, etc., and thus these terms can be used interchangeably. As used herein, the term "belt" refers to a flexible connecting means used to transmit motion between pulleys. The term "belt" refers to any type of belt (e.g., timing belt), chain, etc., and thus these terms can be used interchangeably. The term "encoder" as used herein refers to any type of sensor used or configured to detect and provide electrical feedback indicating the position, direction, speed, count number, and / or orientation of components of the system described herein).

[0026] Conventional material handling systems, such as pallet movers, have drawbacks and inherent limitations. For example, typical handling systems require additional stabilizing wheels to prevent the system from swaying back and forth during acceleration, deceleration, or when traveling on uneven surfaces. In some cases, stabilizing wheels are placed above the drive wheels to prevent the drive wheels from lifting off the ground in dips. However, this configuration leaves room for system sway, which can negatively affect the operation of certain sensors, particularly LiDAR and cameras used for positioning and navigation. Another example is platform systems, which generally require complex equipment for the system to move under pallets and lift / place them onto a fixed platform. Yet another example is the limited maneuverability of three-wheeled kinematic systems in confined spaces, as they cannot move laterally or rotate around their own central axis.

[0027] Examples of displacement-type and adjustable displacement-type differential drive systems described herein improve stability and maneuverability in confined spaces. Furthermore, the examples described herein provide lateral movement and rotation around a central axis for adjustable displacement-type differential drive systems. For example, the examples described herein provide lateral movement and rotation around a central axis for an adjustable displacement-type differential drive system in which the wheels are positioned at opposing ends of a fork. Examples of disclosed displacement-type and adjustable displacement-type differential drive systems are described below with reference to the drawings.

[0028] Figure 1A shows an exemplary pallet moving machine (hereinafter referred to as "machine 100"). In one or more cases, the machine 100 is configured to operate completely autonomously. In one or more other cases, one or more parts of machine 100 are configured to operate manually, and one or more other parts of machine 100 are configured to operate via one or more computer systems, but not limited to the computer system 710 in Figure 7, for example. In one or more cases, machine 100 typically includes a housing, e.g., an A-frame 104, which houses one or more electronic devices, a computing / control system, and one or more batteries, with a drive assembly 102 located beneath the A-frame 104. The A-frame 104 and the drive assembly 102 may be operably connected to forks 106a and 106b, which may include wheels such as wheels 108a and 108b, respectively. The wheels 108a and 108b are attached to the ends of the forks 106a and 106b. For example, the wheels 108a and 108b are positioned at 60% or approximately 60% of the length of the forks 106a and 106b. As shown in Figure 1B, the positions of the wheels 108a and 108b in the longitudinal direction of the forks 106a and 106b correspond to the diameter of the swivel circle TC of the machine 100. In some cases, the wheels 108a and 108b are configured to rotate around their respective vertical axes (see Figure IB). In some cases, the wheels 108a and 108b are configured to rotate around their respective vertical axes (as shown in Figure IB), so that the direction of the wheels 108a and 108b (i.e., the direction of travel of each wheel 108a and 108b) changes based on the rotation of each wheel 108a and 108b. In other cases, the wheels 108a and 108b remain in a fixed direction (i.e., non-steerable), so the wheels 108a and 108b do not swivel circumferentially around their respective vertical axes. The heights of the forks 106a, 106b and the wheels 108a, 108b may be set to a size that allows them to move into cavities, such as the cavity of a pallet. The machine 100 may be configured so that the forks 106a, 106b move up and down to transport objects such as pallets.In some cases, the machine 100 optionally includes a handle 110 operably coupled to the drive assembly 102. The handle 110 can be utilized as a steering mechanism for an operator to control the moving speed and direction of the machine 100.

[0029] FIG. 1A shows that the drive assembly 102 is functionally coupled to the machine 100 to control the movement of the machine 100. However, the drive assembly 102, as well as other drive assemblies such as the displacement differential drive system 200 and the displacement differential drive system 300 described herein, can also be employed in other systems to drive and steer their respective systems. For example, the drive assembly 102, as well as other drive assemblies such as the displacement differential drive system 200 and the displacement differential drive system 300 described herein, can be employed in systems such as a towing device or a trailer device, a floor washer, a shopping cart pusher, and other similar machines configured to move a load, as well as machines that enable movement in narrow spaces. Further, the examples described herein relate to either the drive assembly 102, the displacement differential drive system 200, or the displacement differential drive system 300 disposed at one end of the machine 100, but embodiments where multiple drive assemblies and / or differential drive systems are employed in a machine should also be contemplated. For example, in the case of a machine configured to transport a heavier load (e.g., a large paper roll, a cable reel, a steel part during manufacturing, the manufacture or assembly of heavy machinery), multiple drive assemblies and / or differential drive systems can be operably coupled to the machine to provide improved mobility, torque, and load support capabilities. For example, a machine configured to transport a cable reel can include four adjustable differential drive systems at four locations of the machine, providing mobility in all directions.

[0030] Figure 2 is a top view showing an example of a displacement differential drive system 200 (hereinafter referred to as "system 200"). This system 200 includes drive wheels 202a and 202b, and pulleys 218a and 218b connected to the frame 210 via pivots 204a and 204b, respectively. Pulley 218a is connected to drive wheel 202a via pivot 204a. Pulley 218a is connected to pivot 204a and is positioned coaxially with the vertical axis of pivot 204a. The vertical axis of pivot 204a must be laterally offset from the traction point where drive wheel 202a contacts the ground. Pulley 218b is connected to drive wheel 202b via pivot 204b. Pulley 218b is connected to pivot 204b and is positioned coaxially with the vertical axis of pivot 204b. The vertical axis of pivot 204b must be laterally offset from the traction point where the drive wheel 202b makes contact with the ground. Pulleys 218a and 218b may be configured to rotate the corresponding drive wheels 202a and 202b around the vertical axes of the corresponding pivots 204a and 204b, respectively. For example, pulley 218a rotates the drive wheel 202a around the vertical axis of pivot 204a, changing the orientation of the drive wheel 202a according to the desired direction of travel. In another example, pulley 218b rotates the drive wheel 202b around the vertical axis of pivot 204b, changing the orientation of the drive wheel 202b according to the desired direction of travel. System 200 may be configured as a displacement differential drive system. In some cases, pivot 208 and pulley 212 may be operably connected to belt 206. Pulley 212 is equipped with an encoder and positioned on pivot 208, or at any position between (and including) pulleys 218a and 218b, to provide feedback to the control system regarding the angular direction of drive wheels 202a and 202b. In this simple displacement-type differential drive assembly, both drive wheels 202a and 202b always remain parallel to each other.

[0031] The drive wheels 202a and 202b are configured to rotate forward or backward with a predetermined force to achieve a predetermined travel speed. Each drive wheel 202a and 202b can be displaced a certain distance from the pivot 208 (i.e., the central position between pivots 204a and 204b), and in this way, the distance from the pivot 208 to the drive wheel is the "moment" M with respect to the traction force generated when the system 200 is turned. That is, each drive wheel 202a, 202b may have its own independent moment corresponding to the orientation of the drive wheel (e.g., the distance between the traction point of the drive wheel and the pivot 208). The smaller the moment M, the more difficult the system 200 is to turn, and therefore the stronger the tendency to drive in the straight-line direction. As the distance of the moment M increases, the speed difference between the drive wheels 202a and 202b increases, thereby increasing the rotational force at the pivot 208 and improving steering sensitivity. In some cases, an intentional turning tendency may occur, such as when one drive wheel rotates at a higher rotational speed (RPM) than the other. In one or more other cases, an unintended turning tendency may occur, such as when one drive wheel comes into contact with a small obstacle or encounters an uneven surface.

[0032] The traction point of the drive wheels may include the position where the drive wheels make contact with the ground. In one or more cases, the traction point is laterally offset from the respective pivot axis and / or the vertical axis of the pulley. By operably connecting pulleys 218a and 218b via belt 206, the orientation of pulleys 218a and 218b, and consequently the orientation of drive wheels 202a and 202b, is controlled to steer the system 200. For example, drive wheels 202a and 202b may each be configured to rotate 360 ​​degrees or radially around the vertical axis of the pivot. For example, drive wheel 202a may rotate around the vertical axis of pivot 204a to change its angular orientation relative to the frame 210 to which drive wheel 202a is mounted. As another example, drive wheel 202b may rotate around the vertical axis of pivot 204b to change its angular orientation relative to the frame 210 to which drive wheel 202b is mounted. Due to the difference in rotational speed (RPM) of each drive wheel 202a and 202b, the drive wheels may rotate around the vertical axis of their respective pulleys 218a and 218b. When drive wheels 202a and 202b rotate at the same RPM, the moments of each drive wheel 202a and 202b cancel each other out, and the system 200 moves in a straight line. When one drive wheel rotates at a higher RPM than the other, both drive wheels turn in the direction of the lower-rotating wheel. That is, the driving forces almost cancel each other out, and the remaining driving force multiplied by the moment defines the total turning force of both drive wheels, determining the steering direction of the system 200. When one drive wheel rotates in opposite directions at the same RPM as the other drive wheel, the system 200 may not move significantly on the floor. Rather, the two drive wheels may rotate or change direction from side to side.

[0033] In one or more cases, the encoder may be connected to one or more pulleys and / or pivots. For example, the encoder may be connected to pulley 212. In one or more cases, the encoder may be connected to each of the pulleys 218a, 218b, 212, and / or pivots 204a, 204b, 208. The encoder may be configured to indicate the direction (i.e., angle) of movement of the system 200. In some cases, the encoder may provide a continuous direction indication. The encoder may be, for example, but not limited to, a safety-rated incremental encoder (e.g., SICK DFS60S Pro incremental encoder). In other cases, the encoder may provide a directional indication intermittently.

[0034] Because the drive wheels 202a and 202b are positioned on both sides of the frame 210 (e.g., A-frame), the system 200 offers improved stability when incorporated as a drive assembly into a material handling system such as machine 100. The arrangement of the drive wheels 202a and 202b eliminates the need for stabilizing casters required on either side or one side of the central drive wheel, as is the case with conventional systems. Furthermore, the arrangement of the drive wheels 202a and 202b provides two stable contact points with the ground on both sides of the system 200, thus eliminating wobbling of machine 100. In addition, because the moment M is variable and the drive wheels are offset from the vertical axis of rotation, the steering sensitivity of the drive wheels 202a and 202b can be increased or decreased based on the size and design of machine 100, the load being moved, the floor conditions, or other applications in which the system 200 is used.

[0035] Figure 3A shows an isometric projection of an exemplary adjustable displacement differential drive system 300 (hereinafter referred to as "System 300"). Figure 3B shows an example of a displacement differential steering assembly 301 (hereinafter referred to as "Steering Assembly 301") of System 300. Figure 3C shows a front view of System 300. Figure 3D shows a rear view of System 300 with the steering assembly 301 exposed. Figure 3E shows a top view of System 300 with the steering assembly 301 exposed.

[0036] System 300 includes a steering assembly 301 and drive wheels 202a and 202b, which are located on the frame 210. Drive wheel 202a comprises a gearbox 370a, a motor 372a, a brake 374a, and an encoder 376a, for example as shown in Figure 3C. Drive wheel 202b comprises a gearbox 370b, a motor 372b, a brake 374b, and an encoder 376b, for example as shown in Figure 3C. The motors (e.g., motors 372a and 372b) drive the gearboxes (e.g., gearboxes 370a and 370b) connected to the drive wheels. Encoders 376a and 376b can provide the speed or revolutions per minute of the respective drive wheels 202a and 202b to a computing system (e.g., system 710). Brakes 374a and 374b are, for example, electromechanical brakes configured to decelerate and / or stop the respective drive wheels 202a and 202b. The drive wheels 202a and 202b are aligned with each other along the length L of the frame 210. The steering assembly 301 may include pivots 204a and 204b, one or more steering encoders (e.g., encoders 302a and 302b), an actuator 306, and one or more pulleys (e.g., pulleys 218a, 218b, 314, 320, 326, and 330). The actuator 306 and the pulleys 218a, 218b, 314, and 326 may be operably connected to each other via an adjustment mechanism 308 and a belt 206. A mounting plate 304 can cover one or more components of the steering assembly 301 and enclose and protect the movement of, for example, the pulleys, the belt 206, and the adjustment mechanism 308. The mounting plate 304 can be detachably connected to the frame 210.

[0037] Belt 206 operably connects pulleys 218a, 218b, 314, 320, 326, and 330 to each other. Furthermore, belt 206 can operably connect pulleys 218a, 218b, 314, 320, 326, and 330 to drive wheels 202a and 202b via pivots 204a and 204b. Pulley 314 is positioned adjacent to pivot 204a, pulley 218a, and encoder 302a and is mounted to frame 210 via shaft 316. Shaft 316 is, for example, a spindle shaft connected to frame 210, thereby allowing pulley 314 to rotate around shaft 316 while maintaining a fixed position on frame 210. Pulley 326 is positioned adjacent to pivot 204b, pulley 218b, and encoder 302b and is mounted to frame 210 via shaft 328. The shaft 328 is, for example, a spindle shaft connected to the frame 210, so that the pulley 326 can rotate around the shaft 328 while maintaining a fixed position on the frame 210. Support plates 310 and 312 are connected to the respective shafts of the pulley and encoder, respectively, and support the rotation of the pulley and the steering of the encoder. For example, as shown in Figures 3A and 3D, the input shafts 319a of shaft 328, shaft 336, and encoder 302a are connected to the support plate 310. In another example, as shown in Figures 3A and 3D, the input shafts 319b of shaft 316, shaft 318, and encoder 302a may be connected to the support plate 310.

[0038] The adjustment mechanism 308 is configured to adjust the amount of "toe-in" or "toe-out" between the drive wheels 202a and 202b. In other words, the adjustment mechanism 308 is a steering offset adjustment system. The adjustment mechanism 308 comprises a bottom rigid plate 322 and an upper rigid plate 346 (as shown in Figures 3D and 3F) to which pulleys 320 and 330 are attached, with the pulleys 320 and 330 attached to these plates via shafts 316 and 336, respectively. The shafts 316 and 336 are, for example, spindle shafts connected to the bottom plate 322 and the upper plate 346. The first end of the shaft 316 is connected to the bottom plate 322, and the second opposite end of the shaft 316 is connected to the upper plate 346, so that the pulley 320 can rotate around the shaft 316 while maintaining a fixed position on the adjustment mechanism 308. Similarly, the first end of the shaft 336 is connected to the bottom plate 322, and the second opposite end of the shaft 336 is connected to the upper plate 346, so that the pulley 330 can rotate around the shaft 336 while maintaining a fixed position on the adjustment mechanism 308. In one or more cases, the pulleys 320 and 330 may function as idler pulleys when stationary relative to the shafts 318 and 336. In some cases, a belt tensioner, such as a tensioner 332, may be located on either the pulley 320 or 330. The tensioner 332 may be configured to tighten or loosen the tension of the belt 206 on the pulleys 218a, 218b, 314, 320, 326, and 330. For example, as shown in Figures 3F and 3G, the tensioner 332 includes tension fasteners 380a and 380b operably connected to the respective ends of the shaft 336 via guide blocks 382a and 382b. The tension fasteners 380a and 380b can be rotated in one direction to move their respective guide blocks, and consequently to move the position of the pulley 330, thereby tightening the belt 206. The tension fasteners 380a and 380b can be rotated in the opposite direction to move their respective guide blocks, and consequently to move the position of the pulley 330, thereby loosening the belt 206.

[0039] In one or more cases, when the adjustment mechanism 308 moves along the length L of the frame 210, the adjustment mechanism 308 includes a guide assembly 334 configured to maintain the direction of movement. For example, the guide assembly 334 includes one or more tracks, such as tracks 336a and 336b, as shown in Figures 3C, 3D, and 3F. The tracks are located on one side of the adjustment mechanism 308 (e.g., plates 322 and 346). For example, track 336a may be operably connected to the upper plate 346. In another example, track 336b may be operably connected to the bottom plate 322. Track 336a may include a rigid member 338 mounted on the inner surface of the mounting plate 304 and one or more grooves, such as grooves 346a and 346c, located on the opposing surface of the rigid member 338 and along the length L of the frame 210. The groove may be defined by one or more guides, e.g., guides 340a, 340b, 340c, and 340d, fixed to the outer surface of the upper plate 346. Guides 340a and 340b may be located on one side of the upper plate 346, and guides 340c and 340d may be located on the opposite side of the upper plate 346. The end of the rigid member 338 is shaped and dimensional to move inside the groove 346a defined by guides 340a and 340b and the groove 346c defined by guides 340c and 340d. The track 336b may include a rigid member 342 fixed to either or both of the upper surface 303 and the lower surface 305 of the frame 210. The track 336b may include one or more channels, such as channels 346b and 346d, located along the side of the rigid member 342 and along the length L of the frame 210. The groove may be defined by one or more guides, such as guides 344a, 344b, 344c, and 344d, fixed to the outer surface of the bottom plate 322. Guides 344a and 344b may be located on one side of the bottom plate 322, while guides 344c and 344d may be located on the opposite side of the bottom plate 322. The end of the rigid member 342 is shaped and dimensional so as to move inside the groove 346b defined by guides 344a and 344b and the groove 346d defined by guides 344c and 344d.

[0040] The bottom plate 322 and top plate 346 of the adjustment mechanism 308 each have projections 350, and a rod 324 is positioned between the two plates. Both ends of the rod 324 are connected to the bottom plate 322 and the top plate 346, respectively. The rod 324 is aligned with and connected to the shaft 352 of the actuator 306. The rod 324 may, but is not limited to, a fastener such as a screw. The shaft 352 of the actuator 306 is configured to move in or out of the actuator 306 along the direction of the length L of the frame 210. As the actuator 306 moves the shaft 352, the adjustment mechanism 308 moves in a direction corresponding to the movement of the shaft 352. In one or more cases, a guide assembly 334 is positioned parallel to the length of the shaft 352 to facilitate the direction of movement of the adjustment mechanism 308. The actuator 306 guides the movement of the adjustment mechanism 308 along its length L, thereby configuring the pulleys 320 and 330 to be adjustable in position relative to the pivots 302a and 302b.

[0041] Encoders 302a and 302b may be steering encoders configured, for example, to indicate the angle of movement of the drive wheels 202a and 202b. Encoders 302a and 302b may be connected to the corresponding drive wheels 202a and 202b via pivots 204a and 204b, and pulleys 218a and 218b, respectively. Pivots 204a and 204b may be connected to the frame 210, respectively. The pulleys and encoders (e.g., pulley 218a and encoder 302a) are located on one side of the pivot (e.g., pivot 204a), and the drive wheel (e.g., drive wheel 202a) is located on the opposite side of the pivot. The pivot may be a rigid body housing a portion of the corresponding drive wheel and components that connect the pulleys (e.g., pulleys 218a, 218b) to the drive wheel. The pivot operably connects the pulleys to the drive wheel. For example, pivot 204a operably connects drive wheel 202a to pulley 218a. Pulleys 218a and 218b are configured to rotate drive wheels 202a and 202b around their respective vertical axes based on the direction of movement of belt 206. Pulleys 218a and 218b each receive and connect to the shafts of internal encoders 302a and 302b. Encoders 302a and 302b are configured to determine the angular position of each pulley 218a and 218b, and thus the angular position of the connected drive wheels 202a and 202b. This angular position is provided to a computing system, such as the computing system of machine 100, or another computing system that controls the function of the displacement differential drive system 300. Based on the determined angular position, the computing system can associate the angular position of each shaft with the angular position of each drive wheel. This allows the computing system to determine the overall travel angle of machine 100.

[0042] In one or more cases, one or more computing systems of machine 100, or other computing systems that control the functions of the displacement differential drive system 300, may be configured to control speed and steering. For example, machine 100 may be configured to determine two points (i.e., points that continuously change as the machine moves). One point is "S" (e.g., the target speed of machine 100). The other point is "A" (e.g., the target trajectory, or angle of travel). Machine 100 sets the speed "S" for both drive wheels 202a and 202b. Machine 100 determines the angle "A" as the value to which a virtual center wheel (e.g., a wheel assumed to be located between both drive wheels 202a and 202b) should point. Machine 100 refers to a table showing angles (i.e., the angle of the virtual center wheel) and the corresponding actual angles of each drive wheel 202a and 202b. In some cases, the actual angle of one drive wheel may be greater than the angle of the virtual center wheel (i.e., the actual direction of travel), and the actual angle of the other drive wheel may be smaller than the angle of the virtual center wheel (i.e., the actual direction of travel). Machine 100 can receive / determine the angle value of each drive wheel (e.g., 100 times / second) and the corresponding speed of each drive wheel. In one or more cases, based on the four readings, machine 100 adjusts the angles of each drive wheel 202a, 202b by differential steering (i.e., turning both drive wheels 202a, 202b to the left or right as needed by increasing the speed of one wheel while decreasing the speed of the other wheel). In one or more cases, based on the four readings, machine 100 simultaneously performs Ackermann adjustment by comparing it against a table and determining what the spread should be depending on the angle at which it is moving, and extends or retracts the actuator accordingly. The machine 100 determines that extension of actuator 306 corresponds to an increase in toe-out, and contraction of actuator 306 corresponds to an increase in toe-in.

[0043] In one or more cases, the drive wheels are connected to their respective pivots, so that the vertical axis of the connection to the pivot is laterally offset from the vertical axis of the drive wheel's towing point. The towing point may refer to the point where a portion of the drive wheel contacts the ground surface. For example, as shown in Figure 3C, the vertical axis VA3 of pivot 204a is laterally offset by a distance DS2 from the vertical axis VA4 of the towing point TP2 of drive wheel 202a that contacts the ground G. The vertical axes VA3 and VA4 may be offset from each other by a distance of, for example, 80 mm or about 80 mm (i.e., an 80 mm moment). In another example, the vertical axis VA2 of pivot 204b is laterally offset by a distance DS1 from the vertical axis VAI of the towing point TP1 of drive wheel 202b that contacts the ground G. The vertical axes VA2 and VAI may be offset from each other by a distance of, for example, 80 mm or about 80 mm (i.e., an 80 mm moment).

[0044] Figures 4A to 4E show various configurations of the steering assembly 301 and drive wheels 202a and 202b during driving. Note that the drive systems 200 and 300 described herein are not limited to any specific set of configurations, and therefore the illustrations are for illustrative purposes only. Thus, the drive systems 200 and 300 can independently realize any configuration of the two drive wheels at any point rotating around their respective offset pivots. For example, Figure 4A shows a first configuration in which both drive wheels 202a and 202b are positioned parallel to each other and facing the first side 401 and second side 403 of system 300. In this way, the steering assembly 301 is configured to move in a straight line (e.g., in the longitudinal direction). As another example, Figure 4B shows a second configuration in which both drive wheels 202a and 202b are positioned laterally (e.g., rotated 90 degrees from the first configuration) and facing sides 402 and 404. In the second configuration, the steering assembly 301 is movable laterally (for example, left-right in direction L). Since the drive wheels 202a and 202b are arranged parallel to each other, the adjustment mechanism 308 and actuator 306 are in the same positions as when the drive wheels 202a and 202b are arranged in the first configuration.

[0045] In one or more cases, in the first and second configurations, the actuator 306 can position the adjustment mechanism 308 so that the drive wheels 202a and 202b are arranged parallel to each other based on the respective configuration. Each drive wheel 202a and 202b may be driven at the same speed so that the system 300 can move in a linear direction. For example, in the first configuration, the system 300 may move forward or backward based on the rotation direction of the drive wheels 202a and 202b. As another example, in the second configuration, based on the rotation direction of the drive wheels 202a and 202b, the system 300 moves laterally to the third side 402 or the fourth side 404 of the system 300. When the system 300 transitions from the first configuration to the second configuration, or vice versa, the system 300 may remain stationary while the drive wheels 202a and 202b rotate in opposite directions for a short distance. In other words, the drive wheels 202a and 202b may rotate 90 degrees in opposite directions from each other when transitioning from the first configuration to the second configuration.

[0046] Figure 4C shows a third configuration in which both drive wheels 202a and 202b rotate and Ackermann steering is applied, and therefore the drive wheels 202a and 202b are not parallel to each other. The drive wheels 202a and 202b are oriented in the third configuration for cornering. Figures 4D and 4E show the fourth and fifth configurations, respectively, in which the two drive wheels 202a and 202b are configured at different angles to each other and therefore are not parallel to each other. The drive wheels 202a and 202b in the fourth and fifth configurations are subject to Ackermann steering. In the fourth configuration, the drive wheels 202a and 202b are positioned so that the system 300 can rotate around its center, as shown in Figure 4D.

[0047] In the fifth configuration, the drive wheels 202a and 202b are positioned at the distal end of the machine 100, as shown in Figures 4E, 4F, and 4G, so that the system 300 can move laterally while a moment-generating load 408 is transferred to it. Figure 4F shows the system 300 moving laterally in direction D while a load that generates little to no inertia is transferred to the machine 100. Figures 4E and 4G show the system 300 moving laterally in direction D while a load that generates inertia is transferred to the machine 100. Because the load 408 is positioned on the forks 108a and 108b at a distance from the system (e.g., systems 102, 200, or 300) (as shown in Figures 4E and 4G), the machine 100 is configured to overcome the inertia of the load 408 so as to prevent the machine 100 from moving in an arc. As shown in Figure 4G, when a system (e.g., systems 102, 200, or 300) steers machine 100 in a large arc (e.g., directions Fa and Fb shown in Figure 4G) away from load 408 in the opposite direction, machine 100 overcomes the inertia of load 408. By steering machine 100 in an arc away from load 408 in the opposite direction, the inertial resistance from load 408 is counteracted, and the combined machine 100 and load 408 moves in a straight line laterally (e.g., direction D shown in Figure 4G).

[0048] In the third, fourth, and fifth configurations (i.e., Ackermann steering configurations), each drive wheel is driven at a faster or slower speed than the other drive wheel, resulting in differential steering. Simultaneously, the operation of the actuator 306 moves the adjustment mechanism 308, changing the relative angle of the pulleys 320 and 330, thereby applying Ackermann steering adjustment to the steering assembly 301. For example, the actuator 306 moves the adjustment mechanism 308 by a length L depending on the steering angle or orientation of the drive wheels 202a and 202b.

[0049] If the system 300 is incorporated into, for example, machine 100, the drive wheels 202a, 202b may be located at one end of machine 100, and the non-drive wheels 108a, 108b may be located at the opposite end of machine 100. The non-drive wheels 108a, 108b rotate in the direction of travel. For example, if a load 408 is moved laterally (such as in direction D shown in Figure 4E) via machine 100, the non-drive wheels 108a, 108b are positioned perpendicular to machine 100. The load 408 is placed on the forks 106a, 106b of machine 100. While either of the drive wheels (e.g., drive wheel 202b) is accelerating or decelerating, the inertial effect of the load 408 is felt, attempting to deviate the direction of movement from the intended 90-degree lateral movement direction. The force (e.g., force F1) generated by frictional contact when the drive wheels 202a, 202b and non-drive wheels 108a, 108b move on the ground is strongest at the point where a moment is generated within the frame 210 between the drive wheels 202a, 202b. This force (e.g., forces F2, F3, F4) gradually weakens at the points on the forks 106a, 106b, which are further away from the generated moment.

[0050] As shown in Figures 4E and 4G, in order to move the exemplary load 408 laterally in direction D, the drive wheels 202a and 202b can be positioned at an angle of 2 to 4 degrees, or approximately 2 to 4 degrees, from the first configuration of the drive wheels 202a and 202b, which is off-vertical. The drive wheels 202a and 202b can be positioned so that the ends of the forks 106a and 106b rotate around the frame 210 by applying a force in the direction of movement (e.g., direction D) to the ends of the machine 100 including the system 300. For example, one drive wheel can be configured to maintain an angle of 89 degrees and the other drive wheel can be configured to maintain an angle of 91 degrees. The actuator 306 moves the adjustment mechanism 308 as appropriate to create a 2-degree difference (from the parallel state) and maintain the direction of lateral movement. When lateral movement begins, the inertia of the load 408 pulls the forks 106a and 106b backward. When machine 100 attempts to stop, the moving inertia of load 408 causes forks 106a and 106b to continue moving forward, thereby causing machine 100 to rotate around frame 210. Therefore, the inertia generated by load 408 when machine 100 accelerates deflects machine 100 in one direction, and the inertia generated by load 408 when machine 100 decelerates deflects machine 100 in the opposite direction. Thus, to account for the forces acting on machine 100, the drive wheels 202a and 202b can always adjust their directional angles. In one or more cases, the drive wheels 202a and 202b can rotate at the same rotational speed. When machine 100 is moving at a constant speed, system 300 further utilizes Ackermann steering by increasing the moment at the ends of forks 106a and 106b and offsetting the angles of drive wheels 202a and 202b to move the load laterally as intended. Although the example in Figure 4E illustrates the case where machine 100 is moved laterally, it is understood that the same principle of maintaining the directional angles of the drive wheels 202a and 202b and accelerating / decelerating the rotation of the drive wheels 202a and 202b can be applied to changing the direction of machine 100 or to rotating machine 100 around the center of system 300.

[0051] Figures 5A–5G illustrate an exemplary differential drive system 300, showing additional configurations of the steering assembly 301 and drive wheels 202a, 202b during operation. As described herein, the system 300 may include brakes operably coupled to the pivot and / or pulleys. For example, a brake is operably coupled to the pivot 204a. The brake is configured to lock the orientation of each drive wheel, thereby preventing the drive wheel from rotating unintentionally to another angle. In some cases, the brake is an electromagnetic brake, for example, but not limited to, and is configured to prevent the corresponding drive wheel from rotating / repositioning from its position. In other cases, the brake locks the belt 206 and / or one or more pulleys, preventing the drive wheel from rotating / repositioning from its position. In some cases, one or more brakes are directly coupled to a pulley to lock the rotation of the pulley. In some cases, one or more brakes are directly coupled to the belt 206 to lock the steering by holding the belt. In some cases, the brakes are configured to lock only one side of the drive system, such as the belt 206 of a differential drive system that connects pulleys connected to the steering shafts of each drive unit. For example, it is possible to lock both sides of the drive system by locking any position on one side of the drive system.

[0052] Figure 5A shows the system 300 configured for straight-line driving, in which the drive wheels 202a and 202b are positioned parallel to each other, and the adjustment mechanism 308 is held in place during driving. The drive wheels 202a and 202b can rotate in the same direction and at the same speed to move the system 300 in a straight line. In this configuration, the brakes may not be engaged.

[0053] Figure 5B shows system 300 configured for high-speed straight-line driving or driving on uneven terrain. In this configuration, the drive wheels 202a and 202b are positioned parallel to each other, and the brakes are activated to prevent the drive wheels 202a and 202b from rotating unintentionally. For example, when system 300 is driving on uneven ground, such as crossing a dock plate, the brakes prevent the drive wheels from rotating / redirecting from their positions and maintain the direction of travel. The adjustment mechanism 308 maintains its position even while driving.

[0054] Figure 5C shows the system 300 configured for lateral movement, with the drive wheels 202a and 202b positioned parallel to each other and rotated to a horizontal position around the frame 210. The adjustment mechanism 308 maintains the position during movement. In this configuration, the brakes can be activated optionally. If the brakes are activated, or if the end stop prevents the drive wheel 202a from rotating beyond a certain angle, the rotational speed of the drive wheel 202b is increased at a higher rate than that of the drive wheel 202a (e.g., to move the system 300 to the left), thereby generating a moment that moves the system 300 in the direction of the drive wheel 202b's rotation (e.g., to the left). The system 300 includes one or more sensors to determine the weight of the load on the machine 100 and to determine the orientation of the machine 100 during movement. Feedback from these sensors is provided to the machine 100's calculation system and used to determine the appropriate force difference to apply to the drive wheels 202a and 202b. In some cases, the drive wheels 202a and 202b are configured to automatically adjust their respective current values ​​(i.e., corresponding to torque) so that the same voltage (i.e., the rotational speed of each drive wheel) is applied to each drive wheel. This adjustment is used to ensure that the system 300 is moving in a straight line laterally.

[0055] Figure 5D shows system 300 configured for turning (e.g., a moderately sharp turn such as a right turn). Linkage 308 moves along the length L of frame 210, so that the drive wheels 202a and 202b "toe out" relative to each other. As system 300 is running, linkage 308 moves along length L, continuously adjusting the "toe-in" and "toe-out" of drive wheels 202a and 202b, thereby allowing system 300 to continue turning while running. In this configuration, the brakes may not engage. Figure 5E shows system 300 configured for turning (e.g., a very sharp turn). Linkage 308 moves further along the length L of frame than in the position of linkage 308 in Figure 5D, so that the drive wheels 202a and 202b "toe out" more significantly relative to each other. In this configuration, the brakes may not engage.

[0056] In any configuration described herein, the feedback provided by each encoder 302a, 302b indicates the orientation / angle of each drive wheel 202a, 202b. Based on this feedback, the orientation / angle of each drive wheel 202a, 202b can be adjusted as appropriate, and the steering can be changed as needed based on the difference in rotational speed of each drive wheel 202a, 202b. In one or more cases, the feedback provided by each encoder 302a, 302b allows the calculation system to precisely set the angle of each drive wheel 202a, 202b, achieving minimal wheel skid. Furthermore, the angular offset of each drive wheel 202a, 202b may be continuously adjusted hundreds of times per second. The steering assembly 301 can maintain constant tension on the belt 206 regardless of the orientation of the drive wheels 202a, 202b or the position of the pulleys.

[0057] Figure 5F shows the system 300 configured for rotational movement around the center (RoC position) of the system 300. In one or more cases, to position the drive wheels 202a and 202b at the RoC position, the linkage 308 moves along the length L of the frame 210 in the direction of the drive wheel 202a until the drive wheel 202a rotates to the RoC position. The brake engages with the drive wheel 202a, locking the drive wheel 202a at the RoC position. The linkage 308 then moves in the opposite direction (towards the drive wheel 202b) until the drive wheel 202b rotates to the RoC position. In one or more other cases, to position the drive wheels 202a and 202b at the RoC position, the linkage 308 moves along the length L of the frame 210 in the direction of the drive wheels until both drive wheels are positioned at or approximately positioned at the RoC position. If the drive wheels are not symmetrically arranged but have an appropriate offset depending on the position of the linkage 308, the drive wheels can be positioned in the RoC position by driving one wheel forward and the other wheel backward.

[0058] Figure 6A shows a perspective view of an exemplary differential drive system 300 utilizing another example, a displacement-type differential steering assembly 600 (hereinafter referred to as "steering assembly 600"). Figure 6B shows a front view of the exemplary differential drive system 300 of Figure 6A. Figure 6C is a cross-sectional view of the exemplary steering assembly 600 of Figure 6A utilizing the first rotational configuration 601. Figure 6D is a cross-sectional view of the exemplary steering assembly 600 of Figure 6A utilizing the second rotational configuration 603.

[0059] The steering assembly 600 rotates the pivots 204a, 204b and, consequently the drive wheels 202a, 202b, as described herein, by decreasing or increasing the distance between each pulley or gear, using the first rotation configuration 601 shown in Figures 6A, 6B, and 6C, or the second rotation configuration 603 shown in Figure 6D.

[0060] For example, the first rotation configuration 601 may include a belt 602 operably connecting pulley A1 and pulley A2, a belt 604 operably connecting pulley 1 and pulley 218a, and a belt 606 operably connecting pulley A3 and pulley 218b. Pulleys A1 and 1 may be operably connected on opposite sides of the adjustment gearbox 608. The adjustment gearbox 608 is, for example, a harmonizing gearbox or other type of reduction gearbox. The adjustment gearbox 608 is configured to adjust the rotational position of pulley Al relative to pulley 1. An adjustment gear motor is operably connected to the adjustment gearbox 608 and configured to rotate the adjustment gearbox 608. Based on the rotational direction of the adjustment gearbox 608, the adjusted pulley Al is angularly offset relative to pulley 1. In other words, by moving one pulley (e.g., pulley Al) relative to the other pulley (e.g., pulley 1), pulleys 218a and 218b rotate, and in turn, the drive wheels 202a and 202b rotate via their respective belts. Therefore, the drive wheels 202a and 202b can be "toe-in" or "toe-out" based on the direction of rotation and the amount of adjustment made between the pulleys connected to the adjustment gearbox 608.

[0061] In another example shown in Figure 6D, the second rotational configuration 603 may include gears A1 and A2 operably connected to each other, gears 1 and 2 operably connected to each other and pulley 218a, and gears A3 and A4 operably connected to each other and pulley 218b. Gears Al and gear 1 may be operably connected to opposite sides of the adjustment gearbox 608. The adjustment gearbox 608 may be configured to adjust the rotational position of gear Al relative to gear 1. Based on the rotational direction of the adjustment gearbox 608, the adjusted gear Al is offset relative to gear 1. That is, the adjustment gearbox 608 is configured to adjust the rotational position of one gear relative to the other gear. When adjusting the gears, the adjustment gearbox 608 rotates gear Al and gear 1 in the same rotational direction, but the rotational position of one gear may be offset relative to the other gear. When one gear (e.g., gear Al) is moved relative to the other gear (e.g., gear 1), pulleys 218a and 218b rotate via the operably connected gears, and further, drive wheels 202a and 202b rotate. For example, as gear Al and gear 1 rotate clockwise, gear F (and pulley 218a) rotates in the same clockwise direction, and gear AF (and pulley 218b) rotates in the corresponding counterclockwise direction. Drive wheels 202a and 202b can be "toe-in" or "toe-out" based on the direction of rotation and the amount of adjustment made between the pulleys connected to the adjustment gearbox 608.

[0062] Figure 7 is a block diagram showing the components of a data processing system. Figure 7 is a schematic block diagram, designated 700, showing components of a computing device capable of operating, for example, a differential drive assembly 102, a displacement differential drive system 200, and a displacement differential drive system 300, according to embodiments of this disclosure. Figure 7 is merely an illustrative example of one embodiment and does not imply any limitation to environments in which different embodiments may be implemented. Many modifications can be made to the illustrated environment.

[0063] In one or more cases, one or more of the computing systems 102, 200, and 300 are represented in the form of a general-purpose computing device, such as computing system 710. The components of computing system 710 include, but are not limited to, one or more processors or processing units 714, memory 724, and a bus 716 that connects various system components, including memory 724, to the processing unit 714.

[0064] Bus 716 represents one or more of several types of bus structures, including memory buses or memory controllers, peripheral buses, accelerated graphics ports, and processor buses or local buses using various bus architectures. Exemplary but not limited to these, such architectures include industry standard architecture (ISA) buses, microchannel architecture (MCA) buses, extended ISA (EISA) buses, video electronics standards association (VESA) local buses, and peripheral component interconnect (PCI) buses.

[0065] The computing system 710 typically includes various computer system-readable media. Such media are any available media accessible to the computing system 710, and include both volatile and non-volatile media, as well as removable and non-removable media.

[0066] Memory 724 includes a computing system-readable medium in the form of volatile memory, such as random access memory (RAM) 726 and / or cache memory 728. The computing system 710 may further include other removable / non-removable, volatile / non-volatile computing system storage media. For example, storage system 730 is provided for reading and writing to a non-removable non-volatile medium (e.g., a magnetic medium, not shown, commonly referred to as a “hard drive”) and / or a non-volatile solid-state medium such as flash memory. Not shown, a magnetic disk drive for reading and writing to removable non-volatile magnetic disks, a drive for reading and writing to removable non-volatile solid-state disks (e.g., flash drives), and / or an optical disk drive for reading or writing to removable non-volatile optical disks such as CD-ROMs, DVD-ROMs, and other optical media may be provided. In such cases, each drive is connected to bus 716 via one or more data media interfaces. As will be described later, memory 724 may include at least one computer program product having a set of program modules (e.g., at least one) configured to perform the functions of this embodiment.

[0067] The program / utility 732 has a set of one or more program modules 734, which may be stored in memory 724 together with an operating system, one or more application programs, other program modules, and program data, exemplarily (but not limited to). Each operating system, one or more application programs, other program modules, program data, or combination thereof may include an implementation of a network environment. The program modules 734 generally perform the functions and / or methodologies of the embodiments described herein. The computing system 710 can also communicate with one or more external devices 712, such as a keyboard, pointing device, display 711, or one or more devices that allow the user to communicate with the computer system 710 and any device (e.g., a network adapter, modem, wireless network adapter, Bluetooth adapter, etc.). Such communication is performed via an input / output (I / O) interface 720. Furthermore, the computing system 710 can communicate with one or more networks, such as a local area network (LAN), a general wide area network (WAN), and / or a public network (e.g., the Internet), via a network adapter 718. As shown in the diagram, the network adapter 718 communicates with other components of the computing system 710 via bus 716. It should be understood that other hardware and software components, not shown in the diagram, such as microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data archive storage systems, may be used in conjunction with the computing system 710.

[0068] The embodiments described herein relate to systems, methods, and / or computer program products. A computer program product may include a computer-readable storage medium (or medium) having computer-readable program instructions for causing a processor to perform aspects of the embodiments. The computing system 710 may also be operably connected to a camera 721 (for example, a camera configured to detect lines on the floor of a warehouse facility) and one or more position and / or orientation sensors 713 (such as an accelerometer, gyroscope, and / or LiDAR scanning sensor).

[0069] Computer-readable storage media are tangible devices capable of holding and storing instructions used by instruction execution devices. Computer-readable storage media include, but are not limited to, electronic memory devices, magnetic memory devices, optical memory devices, electromagnetic memory devices, semiconductor memory devices, or appropriate combinations thereof. More specific examples of computer-readable storage media, but are not limited to, include: portable computer floppy disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disk read-only memory (CD-ROM), digital versatile disks (DVDs), memory sticks, floppy disks, devices that mechanically encode instructions using punch cards or grooved projection structures, cloud storage, and appropriate combinations thereof. The computer-readable storage media used herein should not be interpreted as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses passing through fiber optic cables), or electrical signals transmitted through conductors.

[0070] The computer-readable program instructions described herein can be downloaded from a non-temporary computer-readable storage medium to each computing / processing device, or to an external computer or external storage device via a network (e.g., the Internet, a local area network, a wide area network, and / or a wireless network). The network may include copper transmission cables, optical transmission fibers, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface within each computing / processing device receives computer-readable program instructions from the network, transfers the computer-readable program instructions, and stores them in a computer-readable storage medium within each computing / processing device.

[0071] The computer-readable program instructions for performing the operations of the embodiments are either instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as C++ or traditional procedural programming languages ​​such as the C programming language. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer (as a standalone software package), partially on the user's computer and partially on a remote computer, or fully on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer via any type of network, including local area networks (LANs) and wide area networks (WANs), or to an external computer (for example, via the Internet using an Internet service provider). In one or more cases, electronic circuits, including, for example, programmable logic circuits, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), can execute the computer-readable program instructions and perform aspects of the embodiments described herein by leveraging the state information of the computer-readable program instructions to personalize the electronic circuits.

[0072] Aspects of this embodiment are described herein with reference to illustrations and / or block diagrams of the method, apparatus (system), and computer program product. It will be understood that each block in the illustrations and / or block diagrams, as well as combinations of functions within the illustrations and / or block diagrams, can be implemented by non-temporal computer-readable program instructions.

[0073] These computer-readable program instructions are provided to the processor of a general-purpose computer, a dedicated computer, or other programmable data processing device, which can generate a machine, so that the instructions executed via the processor of the computer or other programmable data processing device create means for implementing the functions / operations specified by one or more blocks in a flowchart and / or block diagram. These computer-readable program instructions may also be stored in a computer-readable storage medium that can instruct a computer, a programmable data processing device, and / or other device to operate in a particular manner, so that the computer-readable storage medium storing the instructions becomes a product containing instructions that implement the aspects of the functions / operations defined herein.

[0074] Computer-readable program instructions can be loaded into a computer, other programmable data processing device, or other device, and a series of operational steps can be performed on the computer, other programmable device, or other device to generate a computer implementation process, in which case the instructions executed on the computer, other programmable device, or other device implement the functions / operations described herein (e.g., controlling the orientation of the drive wheels and / or the position of the drive assembly).

[0075] The drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments. In this regard, each block in the block diagram may represent a module, segment, or part of an instruction containing one or more executable instructions for implementing a specified logical function. In some alternative embodiments, the functions shown in the blocks may occur in an order different from the order shown in the drawings. For example, two consecutively shown blocks may be executed substantially in parallel, blocks may be executed in reverse order depending on the functions involved, or blocks may be executed in any order depending on the functions involved. It should also be noted that each block in the block diagram and any combination of blocks within the block diagram may be implemented by a dedicated hardware-based system or a combination of dedicated hardware and computer instructions that performs the specified function or operation.

[0076] The various embodiments described above are provided for illustrative purposes only and should not be construed as limiting the appended claims. Those skilled in the art will readily recognize that various modifications and changes are possible without following the examples and applications illustrated and described herein and without departing from the spirit and scope of the following claims.

Claims

1. A displacement-type differential drive unit, A first drive wheel having a towing point, the first drive wheel being connected to a first pivot having a vertical axis laterally offset from the towing point of the first drive wheel; A second drive wheel having a towing point, the second drive wheel being connected to a second pivot having a vertical axis laterally offset from the towing point of the second drive wheel; A first pulley connected to the first pivot and positioned coaxially with the vertical axis of the first pivot; A second pulley connected to the second pivot and positioned coaxially with the vertical axis of the second pivot; and The system includes a belt that engages and connects the first pulley and the second pulley.

2. A displacement type differential drive unit according to claim 1, Furthermore, it includes an encoder that is operably connected to the first pulley and is positioned coaxially with the vertical axis of the first pivot.

3. A displacement type differential drive unit according to claim 1, Furthermore, it includes a first encoder connected to the first pulley and positioned coaxially with the vertical axis of the first pivot, and a second encoder connected to the second pulley and positioned coaxially with the vertical axis of the second pivot, Here, the first encoder is configured to indicate the direction angle of the first drive wheel, Here, the second encoder is configured to indicate the directional angle of the second drive wheel.

4. A displacement type differential drive unit according to claim 1, Furthermore, the system includes a brake operably connected to at least one of the first pulley and the first drive wheel, The brake is configured to maintain the directional angle of the first drive wheel.

5. A displacement-type differential drive unit according to claim 1, Furthermore, it includes a pulley assembly that engages with the belt, Here, the position of the pulley assembly is adjustable with respect to the first pulley or the second pulley.

6. A displacement differential drive unit according to claim 5, Here, the position of the pulley assembly corresponds to the directional angle of the first drive wheel and the fixed idler pulley that engages with the belt.

7. A displacement differential drive unit according to claim 1, Here, the first drive wheel and the second drive wheel are oriented based on the Ackermann steering configuration.

8. An adjustable differential drive unit, A first drive wheel having a towing point, the first drive wheel being connected to a first pivot having a vertical axis laterally offset from the towing point of the first drive wheel; A second drive wheel having a towing point, the second drive wheel being connected to a second pivot having a vertical axis laterally offset from the towing point of the second drive wheel; A first pulley connected to the first pivot and positioned coaxially with the vertical axis of the first pivot; A second pulley connected to the second pivot and positioned coaxially with the vertical axis of the second pivot; A third pulley, wherein the position of the third pulley relative to the first or second pulley is adjustable; and The system comprises a belt that engages with the first pulley, the second pulley, and the third pulley, and connects them.

9. An adjustable differential drive unit according to claim 8, Furthermore, it is equipped with a fourth pulley, Here, the position of the fourth pulley relative to the first pulley or the second pulley is adjustable, and the belt engages with and connects to the first pulley, the second pulley, the third pulley, and the fourth pulley.

10. An adjustable differential drive unit according to claim 9, Furthermore, it includes an encoder that is operably connected to the first pulley and is positioned coaxially with the vertical axis of the first pivot.

11. An adjustable differential drive unit according to claim 9, Furthermore, the system includes a first encoder arranged coaxially with the vertical axis of the first pivot and connected to the first pulley, and a second encoder arranged coaxially with the vertical axis of the second pivot and connected to the second pulley. Here, the first encoder is configured to indicate the directional angle of the first drive wheel, and here, the second encoder is configured to indicate the directional angle of the second drive wheel.

12. An adjustable differential drive unit according to claim 11, Here, the first drive wheel and the second drive wheel are connected to the frame and arranged to move the frame in a linear direction. Here, the first encoder and the second encoder exhibit the same directional angle as the first drive wheel and the second drive wheel.

13. An adjustable differential drive unit according to claim 11, Here, the first drive wheel and the second drive wheel are connected to the frame and are arranged to move the frame in the rotational direction. Here, the first encoder indicates a first directional angle of the first drive wheel, and the second encoder indicates a second directional angle of the second drive wheel.

14. An adjustable differential drive unit according to claim 13, Furthermore, the system includes a brake operably connected to at least one of the first pulley and the first drive wheel, Here, the brake is configured to engage with the first drive wheel such that the first drive wheel maintains the first directional angle of the first drive wheel, and Here, the first drive wheel and the second drive wheel are arranged to rotate about a central axis.

15. An adjustable differential drive unit according to claim 13, Here, based on the instructed first directional angle of the first drive wheel, the differential drive unit is configured to adjust the second directional angle of the second drive wheel to maintain movement in the rotational direction.

16. An adjustable differential drive unit according to claim 9, Furthermore, it is equipped with a brake that is provided on the vertical axis of the first pivot and connected to the first drive wheel, The brake is configured to maintain the directional angle of the first drive wheel.

17. An adjustable differential drive unit according to claim 9, Furthermore, it has a frame, Here, the first drive wheel and the second drive wheel are positioned on the first side of the frame, Here, the first pulley and the second pulley are positioned on the second side of the frame.

18. An adjustable differential drive unit according to claim 9, Here, the tensioner is connected to either the third pulley or the fourth pulley, Here, the tensioner is configured to adjust the distance between the third pulley and the fourth pulley.

19. An adjustable differential drive unit according to claim 9, Here, the third pulley and the fourth pulley are connected to an actuator configured to position the third pulley and the fourth pulley between the first pulley and the second pulley.

20. An adjustable differential drive unit according to claim 9, Furthermore, the system includes a computing platform configured to control the rotational motion and orientation of the first drive wheel and the second drive wheel, respectively, based on at least encoder information.

21. An adjustable differential drive unit, comprising: A first drive wheel having a towing point, the first drive wheel being connected to a first pivot having a vertical axis laterally offset from the towing point of the first drive wheel; A second drive wheel having a towing point, this second drive wheel is connected to a second pivot having a vertical axis laterally offset from the towing point of the second drive wheel; A first rotary actuator connected to the first pivot and positioned coaxially with the vertical axis of the first pivot; A second rotary actuator connected to the second pivot and positioned coaxially with the vertical axis of the second pivot; and A steering assembly that connects the first rotary actuator and the second rotary actuator and orients at least one of the first drive wheel and the second drive wheel in a direction that provides Ackermann steering.

22. An adjustable differential drive unit according to claim 21, Here, the first rotary actuator includes a first pulley, the second rotary actuator includes a second pulley, and the steering assembly includes an adjustable pulley assembly that engages with a belt connecting the first pulley, the second pulley, and the adjustable pulley assembly.

23. An adjustable differential drive unit according to claim 21, Here, the first rotary actuator is equipped with a first gear, and the second rotary actuator is equipped with a second gear. The steering assembly comprises the following: Adjustable gearbox and motor, This adjustment gearbox is operably connected to the first gear via a first pulley or at least one gear, and operably connected to the second gear via a second pulley or at least one other gear.

24. An adjustable differential drive unit according to claim 23, The first drive wheel and the second drive wheel are oriented based on the amount and direction of rotation of the adjustment gearbox.

25. A displacement differential drive unit, comprising: A first drive wheel having a towing point, the first drive wheel being connected to a first pivot having a vertical axis laterally offset from the towing point of the first drive wheel; A second drive wheel having a towing point, the second drive wheel being connected to a second pivot having a vertical axis laterally offset from the towing point of the second drive wheel; A first pulley connected to a first pivot and positioned coaxially with the vertical axis of the first pivot; A second pulley connected to a second pivot and positioned coaxially with the vertical axis of the second pivot; and One or more belts connecting the first pulley and the second pulley.

26. A displacement type differential drive unit according to claim 25, Furthermore, it includes an encoder that indicates the direction of at least one drive wheel, and the encoder is directly connected to one or more pulleys or to a belt that circles the pulleys.

27. A displacement type differential drive unit according to claim 26, Here, the first drive wheel and the second drive wheel are rotatably supported within the frame, with the first drive wheel positioned on one side of the frame and the second drive wheel positioned on the other side of the frame.

28. A displacement type differential drive unit according to claim 27, Here, the first drive wheel and the second drive wheel each have their own drive means, such as an electric motor or a gearbox, and can be operated independently in order to travel at the same speed or different speeds.

29. A displacement type differential drive unit according to claim 28, Here, differential steering is achieved by driving one drive wheel at a higher speed than the other drive wheel, and both drive wheels are connected by a belt and steered in the same direction by the same amount, maintaining the same angular offset in some cases.

30. An adjustable differential drive unit, comprising: A first drive wheel having a towing point, the first drive wheel being connected to a first pivot having a vertical axis laterally offset from the towing point of the first drive wheel; A second drive wheel having a towing point, the second drive wheel being connected to a second pivot having a vertical axis laterally offset from the towing point of the second drive wheel; A first pulley connected to a first pivot and positioned coaxially with the vertical axis of the first pivot; A second pulley connected to a second pivot and positioned coaxially with the vertical axis of the second pivot; Third pulley and fourth pulley, where the positions of the third pulley and the fourth pulley are movable relative to the first pulley and the second pulley; and A belt that engages with and connects the first pulley, the second pulley, the third pulley, and the fourth pulley.

31. A displacement type differential drive unit according to claim 30, Furthermore, the system includes actuators that can move the second pulley and the third pulley in one direction or the other relative to each other, thereby adjusting the angular direction of one drive wheel in comparison to the other drive wheel.

32. A displacement type differential drive unit according to claim 31, Here, the third pulley, the fourth pulley, the steering assembly supporting them, and the actuator that moves them simultaneously constitute the steering offset adjustment system.

33. A displacement type differential drive unit according to claim 32, Here, the first drive wheel and the second drive wheel can rotate at different speeds, thereby enabling steering and simultaneously activating the steering offset adjustment system. By combining these, various drive functions can be provided.

34. A displacement type differential drive unit according to claim 33, One of these features is Ackermann steering.

35. A displacement type differential drive unit according to claim 33, Here, one of these features is steerable lateral movement.

36. A displacement type differential drive unit according to claim 33, Here, one of these functionalities is to rotate the machine around a fixed point or a vertical axis.

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