, Description:
FIELD OF THE INVENTION
[0001] The present disclosure generally relates to a system and method for an efficient driving mechanism for autonomous robots, and more particularly relates to an efficient driving mechanism that includes five omni-wheels.

BACKGROUND
[0002] The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Autonomous self-driving machines (also popularly known as robots) are not only changing the present world but are also becoming one of the most important human-creations of all time. Be it in healthcare, manufacturing, or any other industry, these self-driving machines are penetrating deep into their applications and therefore are being widely adopted.
[0004] Robust navigation is one of the key problems in the robotics industry, wherein roboticists are endeavouring hard to find an elegant solution. One of such problems that exists involves traction between ground and wheels, which makes turning about a pivot position difficult. In other words, due to such traction, load carrying capacity gets heavily reduced due to tremendous frictional force on the wheels coupled to mobile robot.
[0005] There is therefore a need in the art for an improved mechanism/system that can help overcome the above-mentioned drawback.
[0006] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

OBJECTS OF THE INVENTION
[0007] It is an object of the present disclosure to provide an improved mechanism/system that can help overcome the above-mentioned drawbacks.
[0008] It is an object of the present disclosure to provide an improved mechanism/system that focuses on wheel placement, driving mechanism, motors, and uses five Omni-wheels over conventional four wheel chassis to get better stability, mobility and improved payload.
[0009] It is an object of the present disclosure to provide an improved mechanism/system that incorporates a fifth-wheel that uses DC motor that is placed at the back orthogonally to the other four Omni-wheels, wherein the fifth-wheel gets activated only during turning of robot about its pivot position.

SUMMARY
[0010] The present disclosure generally relates to a system and method for an efficient driving mechanism for autonomous robots, and more particularly relates to an efficient driving mechanism that includes five omni-wheels.
[0011] The present disclosure provides an improved mechanism/system that focuses on wheel placement, driving mechanism, motors, and uses five Omni-wheels over conventional four wheel chassis to get better stability, mobility and improved payload. The present disclosure further provides an improved mechanism/system that incorporates a fifth-wheel that uses DC motor that is placed at the back orthogonally to the other four Omni-wheels, wherein the fifth-wheel gets activated only during turning of robot about its pivot position. In an aspect, the four wheels use stepper motors, unlike the fifth wheel that, as mentioned above, uses a DC motor. Using a DC motor on the fifth wheel is an energy saving solution that would not have been possible in case of stepper motor. Therefore, a power efficient, high performance driving mechanism is designed.
[0012] In an aspect, the present disclosure relates to an autonomous robot comprising a wheel base, wherein the wheel base comprises four wheels (A, B, C, and D) of which wheels A and D are positioned on one side of the wheel base, and wheels B and C are positioned on other side of the wheel base; and a fifth wheel (E) positioned orthogonal to the four wheels and configured to provide support by distributing load across the four wheels and the fifth wheel, said fifth wheel providing extra torque for movement and distribution of the load.
[0013] In an aspect, the four wheels and the fifth wheel can be omni-wheels having small discs around circumference and are perpendicular to turning direction.
[0014] In another aspect, each of the four wheels can be operatively coupled with a stepper motor, and wherein the fifth wheel is operatively coupled with a DC motor. In another aspect, the fifth wheel can be turned ON by the DC motor only during rotation.
[0015] In another aspect, distance between wheels A and B is greater than distance between wheels A and D.
[0016] In another aspect, the robot can have a differential steering mechanism.
[0017] In yet another aspect, the fifth wheel can be positioned towards the rear end of the wheel base.

BRIEF DESCRIPTION OF DRAWINGS
[0018] FIG. 1 illustrates an exemplary representation of the wheel base of the proposed robot in accordance with an embodiment of the present disclosure
[0019] FIG. 2 depicts an exemplary representation showing rotation of the proposed robot about its pivot position in accordance with an embodiment of the present disclosure.
[0020] FIG. 3 depicts an exemplary representation showing the proposed robot after completing 90 degrees of anti-clockwise rotation about its pivot position in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION OF DRAWINGS
[0021] Embodiments of the present disclosure include various steps, which will be described below. The steps may be performed by hardware components or may be embodied in machine-executable instructions, which may be used to cause a general-purpose or special-purpose processor programmed with the instructions to perform the steps. Alternatively, steps may be performed by a combination of hardware, software, firmware and/or by human operators.
[0022] Embodiments of the present disclosure may be provided as a computer program product, which may include a machine-readable storage medium tangibly embodying thereon instructions, which may be used to program a computer (or other electronic devices) to perform a process. The machine-readable medium may include, but is not limited to, fixed (hard) drives, magnetic tape, floppy diskettes, optical disks, compact disc read-only memories (CD-ROMs), and magneto-optical disks, semiconductor memories, such as ROMs, PROMs, random access memories (RAMs), programmable read-only memories (PROMs), erasable PROMs (EPROMs), electrically erasable PROMs (EEPROMs), flash memory, magnetic or optical cards, or other type of media/machine-readable medium suitable for storing electronic instructions (e.g., computer programming code, such as software or firmware).
[0023] Various methods described herein may be practiced by combining one or more machine-readable storage media containing the code according to the present disclosure with appropriate standard computer hardware to execute the code contained therein. An apparatus for practicing various embodiments of the present disclosure may involve one or more computers (or one or more processors within a single computer) and storage systems containing or having network access to computer program(s) coded in accordance with various methods described herein, and the method steps of the disclosure could be accomplished by modules, routines, subroutines, or subparts of a computer program product.
[0024] If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[0025] Arrangements and embodiments may now be described more fully with reference to the accompanying drawings, in which exemplary embodiments may be shown. Embodiments may, however, be embodied in many different forms and should not be construed as being limited to embodiments set forth herein; rather, embodiments may be provided so that this disclosure will be thorough and complete, and will fully convey the concept to those skilled in the art.
[0026] The suffixes ‘module’, ‘unit’ and ‘part’ may be used for elements in order to facilitate the disclosure. Significant meanings or roles may not be given to the suffixes themselves and it is understood that the ‘module’, ‘unit’ and ‘part’ may be used together or interchangeably.
[0027] The present disclosure generally relates to a system and method for an efficient driving mechanism for autonomous robots, and more particularly relates to an efficient driving mechanism that includes five omni-wheels that are powered using a combination of steppers and DC motor to improve efficiency. This proposed mechanism (also interchangeably referred to as system, device, architecture or apparatus) allows the mobile (also interchangeably referred to as autonomous) robot to carry high payload at low cost. The proposed mechanism also enables improved turning capability when five-wheeled autonomous robot is driven using differential steering mechanism. The proposed design is preferred over conventional robot designs vis-à-vis robots employing traditional wheeled chassis, providing autonomous robot as a low cost solution.
[0028] In an exemplary aspect, the proposed invention pertains to solving issues pertaining to any or a combination of payload, mobility, stability, ground clearance, power consumption and positional accuracy of one or more autonomous robots. It has been observed that when payload is increased gradually; mobility of the robot is greatly reduced thereby reducing the performance.
[0029] In an aspect, the present disclosure relates to an autonomous robot comprising a wheel base, wherein the wheel base comprises four wheels (A, B, C, and D) of which wheels A and D are positioned on one side of the wheel base, and wheels B and C are positioned on other side of the wheel base; and a fifth wheel (E) positioned orthogonal to the four wheels and configured to provide support by distributing load across the four wheels and the fifth wheel, said fifth wheel providing extra torque for movement and distribution of the load.
[0030] In an aspect, the four wheels and the fifth wheel can be omni-wheels having small discs around circumference and are perpendicular to turning direction.
[0031] In another aspect, each of the four wheels can be operatively coupled with a stepper motor, and wherein the fifth wheel is operatively coupled with a DC motor. In another aspect, the fifth wheel can be turned ON by the DC motor only during rotation.
[0032] In another aspect, distance between wheels A and B is greater than distance between wheels A and D.
[0033] In another aspect, the robot can have a differential steering mechanism.
[0034] In yet another aspect, the fifth wheel can be positioned towards the rear end of the wheel base.
[0035] An exemplary aspect of proposed system can be presented keeping in the mind that autonomous robot can be deployed in a hospital, wherein a user can measure performance of the autonomous robot in terms of Payload that is improved by preferring 5 Omni-wheels. An additional fifth wheel so placed at the back on base minimizes frictional force on system by providing additional torque. Also, this reduces the load on four wheels, enabling the robot to now carry even higher payloads. This intuitive approach helps to carry much heavier weight for hospital utility.
[0036] Performance of the proposed robot is further enhanced in terms of Mobility where traditional chassis design in robots shows signs of immobility while taking turns at lower and high speeds, and therefore the present disclosure focuses on five Omni-wheeled chassis. What makes this design unique is the addition of fifth Omni-wheel placed at the back orthogonally to the other Omni-wheels as depicted in FIG. 1. This aspect assists in manoeuvrability, wherein the wheels use small rollers along the wheel's edges, providing a minimum amount of friction sideways, allowing the wheels to move in any direction. Omni wheels have smaller rollers on the edges that move completely perpendicular to the wheel itself. Manoeuvrability is further enhanced as because of the proposed arrangement left and right turning capability is improved as fifth wheel carries the load in the direction intended without drag.
[0037] Another performance parameter of the proposed robot includes ground clearance, which is improved by varying the size. Almost every hospital includes lifts that have sufficient space between lift and floor. Another added advantage is to possibly avoid obstruction below the base. Hence sufficient clearance is a must.
[0038] Yet another performance parameter of the proposed robot includes stability, which is improved after research and analysing the base design so as to lower the center of mass. Placement of wheels on the mobile robot at the predefined distance helps in maintaining the force on the carrier base thereby distributing the load equally on wheels; avoiding toppling.
[0039] Yet another performance parameter pertain to power consumption, wherein due to limited power supply, the proposed apparatus/system/mechanism, instead of running with an all packed 5 stepper motors, runs 4 wheels on stepper motors and the fifth/new wheel on DC motor. Additionally, when load is reduced on the steppers due to addition of fifth wheel, power drawn is minimized, leading to less amperage draw. This combination saves around 20-25 % energy as DC motor is switched specifically during turnings, unlike all getting powered at the same time. This increases the running time thereby adding the efficiency to the system.
[0040] Another performance attribute that is positively impacted through the proposed autonomous robot involves the braking mechanism, wherein steppers provide better positional accuracy because they have high precision compared to traditional’ brushed DC motor as they turn constantly as soon as enough power is applied, whereas stepper motors can be turned an exact number of steps (this varies from motor to motor but in a standard 200 step motor this equates to 1.8 degrees per step). This can then enable the motor to move from one fixed position to another fixed position at any point of the circle.
[0041] In an exemplary aspect, the proposed autonomous robot can be configured to incorporate a Differential steering as Ackermann steering requires complex design and additional drives, servos and control hence differential is preferred. Additionally, Autonomous Mobile Robot (AMR) requires sharp turn to pass through narrow places, which cannot be achieved in Ackermann steering since it requires pivot rotation (which is provided by differential steering).
[0042] In an aspect, the proposed invention pertains to 4-wheel drive system with an additional powered fifth wheel placed at the back orthogonally so as to better control the robot. Wheel placement plays a critical role in the movement of the robot, and therefore the present invention analyzed the following types of wheel placement that can help choose best performing among them. In an aspect, as part of a first exemplary design, when distance of front wheel and back wheel is very large, in order to rotate about pivot position, right wheels are turned in clockwise (CW) direction, while left wheels in counter-clock-wise (CCW) direction. Since the distance between the front and back wheels is large, it cuts the circular pull of the front and back wheels, resulting in wheels to drag due to heavy load, and as the traction is large, it acts in the opposite direction of drag, resulting in no movement. Turning can be achieved by increasing motor power which would draw more power resulting in changing the battery hence being less economical. As part of the second exemplary design, for reducing the distance between the wheels further, the wheels can be positioned such that the distance between the front and the back wheels is almost equal to the left and right wheels. The proposed invention demonstrates better performance than the above mentioned as, in the proposed system, circular pull provided by the back wheels is large but there still occurs some drag force hindering the turning of the wheels. In yet another aspect, as part of the third exemplary design, distance between front and back wheels can be less compared to the right and left wheels as shown in FIG. 1, which is an optimal placement of wheels and can be used in differential steering as it produces the least amount of drag on the wheels and the turning is achieved easily. This design produces less drag compared to first/second design and provides better stability to the body by keeping the center of gravity within the wheels.
[0043] Additionally, placement of fifth wheel, as shown in FIG. 1, in orthogonal position provides support by distributing load on 5 wheels, which not only increases the payload, but also amplifies the manoeuvrability. Hence, efficient wheel placement acts as a life support system, enhancing movement, especially the rotation about pivot position of autonomous robot.
[0044] In an aspect, Omni wheels have small discs around the circumference which are perpendicular to the turning direction. The effect is that the wheel can be driven with full force, but will also slide laterally with great ease. Hence with this type of wheels, the drag was almost negligible providing better turning about pivot position.
[0045] In an aspect, size of the wheel can be based on clearance of the robot, for instance, in the hospital example/embodiment, based on the gap of the elevator and the floor.
[0046] In an aspect, Omni directional wheel has three DOF and functions as a normal wheel, but provides low resistance in another direction as well. An exemplary advantage of this design is that by employing one wheel at back and using 4 stepper motors and 1 DC motor, as shown in FIG. 1, turning capability because of additional torque, additional payload due to load distribution, and positional accuracy due to steppers is achieved. This intuitive design and method improves efficiency and performance without modifying base design and using high capacity motors; therefore keeping the manufacturing cost low.
[0047] In an aspect, with reference to FIG. 1, the representations shows wheel base structure at position A where Omni-wheels are attached to base F. As shown, distance between wheel A and wheel B is greater than distance between wheel A and wheel D, which minimizes frictional force at the point of contact with the floor during rotation hence improving manoeuvrability. Wheel E in the present disclosure has an important role and can be placed orthogonally to wheels A, B, C and D, wherein wheel E can be configured to supports the wheel base by providing extra torque for movement and distributes payload, thereby increasing load carrying capacity of the robot. This wheel is connected to DC motor M5, which only turns ON during rotation, which technique adds strength to robot to carry out complex movement in narrow places with ease.
[0048] Position B as shown in FIG. 2 depicts rotation about its pivot position. Label X shows the robot movement at a certain angle. Position C as shown in FIG. 3 depicts the robot after completing 90 degrees of anti-clockwise rotation about its pivot position. FIGs. 1-3 can be used to explain inventive-step of using mobile robot in hospitals (only a non-limiting example) without going for high capacity motors and load carrying wheels.
[0049] In an aspect therefore, the present disclosure relates to an autonomous robot having differential steering mechanism comprising of five wheels (A, B, C, D, E) two on each side (A, D and B, C) driven using differential steering mechanism and one at back (E) placed orthogonally, which provides additional torque that helps in rotation in narrow space in hospital. In addition, the proposed autonomous robot can have a differential mechanism further comprising a combination of four stepper motors (M1, M2, M3 and M4) on side wheels (A, B, C, D) and one DC motor (M5) on the back wheel (E), which improves efficiency and performance. In an aspect, the stepper motors can have high gear ratio, and therefore geared motors allow carrying higher payloads since high gear ratio creates more torque. For the same payload considered in this invention, opting high capacity motors will reduce the overall performance and efficiency due to enormous power consumption.
[0050] In a non-limiting exemplary aspect, payload being carried by the proposed robot can be between 80-120 Kgs, whereas the total weight of the base including wheels can be between 10-20 Kgs, and the wheel dimension in an aspect can be in the range of 120-180 mm in diameter.
[0051] As used herein, and unless the context dictates otherwise, the term “coupled to” is intended to include both direct coupling; in which two elements that are coupled to each other contact each other, and indirect coupling; in which at least one additional element is located between the two elements. Therefore, the terms “coupled to” and “coupled with” are used synonymously. Within the context of this document terms “coupled to” and “coupled with” are also used euphemistically to mean “communicatively coupled with” over a network, where two or more devices are able to exchange data with each other over the network, possibly via one or more intermediary device.
[0052] It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refer to at least one of something selected from the group consisting of A, B, C … and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc. The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims.
[0053] While various embodiments of the present disclosure have been illustrated and described herein, it will be clear that the disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the disclosure, as described in the claims.

ADVANTAGES OF THE INVENTION
[0054] The present disclosure provides an improved mechanism/system that can help overcome the above-mentioned drawbacks.
[0055] The present disclosure provides an improved mechanism/system that focuses on wheel placement, driving mechanism, motors, and uses five Omni-wheels over conventional four wheel chassis to get better stability, mobility and improved payload.
[0056] The present disclosure provides an improved mechanism/system that incorporates a fifth-wheel that uses DC motor that is placed at the back orthogonally to the other four Omni-wheels, wherein the fifth-wheel gets activated only during turning of robot about its pivot position.

Claims:1. An autonomous robot comprising a wheel base, said wheel base comprising:
four wheels (A, B, C, and D) of which wheels A and D are positioned on one side of the wheel base, and wheels B and C are positioned on other side of the wheel base; and
a fifth wheel (E) positioned orthogonal to the four wheels and configured to provide support by distributing load across the four wheels and the fifth wheel, said fifth wheel providing extra torque for movement and distribution of the load.
2. The robot as claimed in claim 1, wherein the four wheels and the fifth wheel are omni-wheels having small discs around circumference and are perpendicular to turning direction.
3. The robot as claimed in claim 1, wherein each of the four wheels is operatively coupled with a stepper motor, and wherein the fifth wheel is operatively coupled with a DC motor.
4. The robot as claimed in claim 3, wherein the fifth wheel is turned ON by the DC motor only during rotation.
5. The robot as claimed in claim 1, wherein distance between wheels A and B is greater than distance between wheels A and D.
6. The robot as claimed in claim 1, wherein the robot has a differential steering mechanism.
7. The robot as claimed in claim 1, wherein the fifth wheel is positioned towards the rear end of the wheel base.