DESC:CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of provisional patent application having Patent Application No. 201941012885 filed on 30th day of March 2019 in India.
FIELD OF INVENTION
[0001] Embodiments of the present disclosure relates to a mobile robot which use mechanical limbs for movement, and more particularly to a leg assembly of multilegged walking robot.
BACKGROUND
[0002] Walking robots have good ground adaptability when compared with wheeled and crawler ground mobile robots. The specific walking robots are more versatile than wheeled robots and can traverse many different terrains. Such robots often imitate legged animals, such as humans or insects, thus there is an increased complexity and a high-power consumption. Further, to operate the walking robots a complicated and perfect control system is also required.
[0003] The main challenges are the planning and implementation of leg assembly motion of a walking robot. A complex mechanical leg assembly is required to generate a walking sequence or to generate ways to plan the steps of the walking robot. Such leg assembly will enable the walking robot to move in a desirable way. While moving, the leg assembly should maintain equilibrium constraints required for the stability of the robot.
[0004] In conventional approach, the leg assembly of any walking robot provides poor rigidity with large energy consumption. Here, an actuator has to take the load even when the robot is standing still on level ground. Undue energy is consumed in such process. Moreover, majority of the energy input to the actuators goes into lifting the robot body against gravity rather than propelling it forward. More efficient approach would be to provide three degrees of freedom for the walking robot body while moving.
[0005] Hence, there is a need for an improved leg assembly of a robot to address aforementioned issues.

BRIEF DESCRIPTION
[0006] In accordance with one embodiment of the disclosure, a leg assembly of a robot is provided. The leg assembly of the robot comprises a leg frame. The leg frame is mechanically coupled to a robot platform base. The leg frame is configured to attach one or more motor assembly with the robot platform base. The leg assembly of the robot also comprises a manipulator. The manipulator is mechanically coupled to the one or more motor assembly. The manipulator is configured to hold a telescopic leg sub-assembly.
[0007] The leg assembly of the robot also comprises the telescopic leg sub-assembly. The leg sub-assembly is mechanically coupled to the manipulator. The leg sub-assembly comprises a linear actuator. The leg sub-assembly also comprises a foot. The leg sub-assembly also comprises a revolute joint. The revolute joint is configured to rotate the foot to rotate about the telescopic leg axis.
[0008] To further clarify the advantages and features of the present disclosure, a more particular description of the disclosure will follow by reference to specific embodiments thereof, which are illustrated in the appended figures. It is to be appreciated that these figures depict only typical embodiments of the disclosure and are therefore not to be considered limiting in scope. The disclosure will be described and explained with additional specificity and detail with the appended figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The disclosure will be described and explained with additional specificity and detail with the accompanying figures in which:
[0010] FIG. 1 is a schematic representation of a leg assembly of a robot in accordance with an embodiment of the present disclosure;
[0011] FIG. 2 is a schematic representation of an embodiment representing the leg assemblies of the robot of FIG. 1 mechanically attached with robot platform base in accordance of an embodiment of the present disclosure;
[0012] FIG. 3 is a block diagram representation of an embodiment representing a sub-system to control function of the leg assembly of the robot of FIG. 1 in accordance with an embodiment of the present disclosure;
[0013] FIG. 4 is a schematic representation that illustrates an exemplary multi-legged robot with the leg assembly of FIG. 1 in accordance with an embodiment of the present disclosure;
[0014] FIG. 5 is a schematic representation that illustrates an exemplary multi-legged robot with the leg assembly of FIG. 1 in accordance with an embodiment of the present disclosure;
[0015] FIG. 6 is a schematic representation that illustrates an exemplary actuating mechanism of multi-legged robot with the leg assembly of FIG. 1 in accordance with an embodiment of the present disclosure; and
[0016] FIG. 7 is a schematic representation that illustrates an exemplary multi-legged robot with the leg assembly of FIG. 1 in accordance with an embodiment of the present disclosure;
[0017] Further, those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the figures by conventional symbols, and the figures may show only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the figures with details that will be readily apparent to those skilled in the art having the benefit of the description herein.
DETAILED DESCRIPTION
[0018] For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiment illustrated in the figures and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Such alterations and further modifications in the illustrated online platform, and such further applications of the principles of the disclosure as would normally occur to those skilled in the art are to be construed as being within the scope of the present disclosure.
[0019] The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such a process or method. Similarly, one or more devices or subsystems or elements or structures or components preceded by "comprises... a" does not, without more constraints, preclude the existence of other devices, subsystems, elements, structures, components, additional devices, additional subsystems, additional elements, additional structures or additional components. Appearances of the phrase "in an embodiment", "in another embodiment" and similar language throughout this specification may, but not necessarily do, all refer to the same embodiment.
[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs. The system, methods, and examples provided herein are only illustrative and not intended to be limiting.
[0021] In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings. The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.
[0022] Embodiments of the present disclosure relates to a leg assembly of a robot. The leg assembly of the robot comprises a leg frame. The leg frame is mechanically coupled to a robot platform base. The leg frame is configured to attach one or more motor assembly with the robot platform base. The leg assembly of the robot also comprises a manipulator. The manipulator is mechanically coupled to the one or more motor assembly. The manipulator is configured to hold a telescopic leg sub-assembly.
[0023] The leg assembly of the robot also comprises the telescopic leg sub-assembly. The leg sub-assembly is mechanically coupled to the manipulator. The leg sub-assembly comprises a linear actuator. The leg sub-assembly also comprises a foot. The leg sub-assembly also comprises a revolute joint. The revolute joint is configured to rotate the foot to rotate about the telescopic leg axis.
[0024] FIG. 1 is a schematic representation of a leg assembly of a robot (10) in accordance with an embodiment of the present disclosure. As used herein, the term “robot” refers to a machine resembling a human being and able to replicate certain human movements and functions automatically.
[0025] As used herein, the “robot platform” is referred to the body structure of the robot, which enables in carrying payload. In one embodiment, the leg assembly of the robot assembly (10) comprises of links and joints (a linkage) intended to simulate the walking motion of humans or animals.
[0026] The leg assembly of the robot (10) comprises a leg frame (20). The leg frame (20) is mechanically coupled to a robot platform base (140). (as shown in FIG. 2) The leg frame (20) is configured to attach one or more motor assembly (30) with the robot platform base (140). In one embodiment, a robot refers to a specific multi-legged robot (130), capable of locomotion such as quadruped robots or hexapod robots. In such embodiment, the multi-legged robot (130) uses Direct Current (DC) motor for performing locomotion function.
[0027] Furthermore, in another embodiment, the leg assembly of the robot (10) is attached to a pre-determined position under the robot platform base (140). It would be appreciated by those skilled in the art, that the attachment of the leg assembly of the robot (10) in the pre-determined position enables maintenance of the vertical centre of mass of the multi-legged robot (130). (as shown in FIG. 2)
[0028] The leg assembly (10) of the robot also comprises a manipulator (80). The manipulator (80) is mechanically coupled to the one or more motor assembly (30). The manipulator (80) is configured to hold a telescopic leg sub-assembly (90). In one embodiment, the manipulator (80) may comprise a parallel manipulator (as shown in FIG. 1) or a serial manipulator.
[0029] In one exemplary embodiment, the one or more motor assembly (30) functions as an actuator, enabling the movement of the parallel manipulator (40, 50, 60, 70). The parallel manipulator (40, 50, 60, 70) is configured to hold a telescopic leg sub-assembly (90). As used herein, the term “actuator” refers to a device that causes a machine or other device to operate.
[0030] In another exemplary embodiment, the one or more motor assembly (30) has revolute joints (210, 220) which are not actuated. In such embodiment, the outer links (60, 40) will be the telescoping arms of linear actuators. The revolute joint between the outer links (60, 40) becomes the prismatic joint of two linear actuators (230 and 240). The vertical telescopic leg is attached to one of the extended arms (60 and 40). (as shown in FIG. 6 & FIG. 7)
[0031] In continuation of FIG. 1, the parallel manipulator (40, 50, 60, 70) comprises of four links. In one embodiment, one of the outer links (60, 70) of the parallel manipulator is extended to hold the telescopic leg sub-assembly (90). In such embodiment, one of the inside links (40, 50) of the parallel manipulator is fabricated to mechanically couple to the one or more motor assembly (30).
[0032] Furthermore, it would be appreciated by those skilled in art, that the parallel manipulator (40, 50, 60, 70) provides two degrees of freedom. In such exemplary embodiment, both the degrees of freedom of the parallel manipulator (40, 50, 60, 70) are actuated in the horizontal plane which allows the tip or end-effector of the manipulator (80) to move in horizontal plane along x and y axes.
[0033] The leg assembly of the robot (10) also comprises the telescopic leg sub-assembly (90). The telescopic leg sub-assembly (90) is mechanically coupled to the manipulator (80). The telescopic leg sub-assembly (90) comprises a linear actuator (100). In one embodiment, non-back driveable telescopic legs help in holding the height of the robot body without wasting energy. As used herein, the term “telescopic leg” refers to legs which ensures a fluent regulation of the platform height in the defined range.
[0034] Moreover, in one embodiment, the linear actuator (100) enables the movement of a telescopic rod in vertical plane. In such embodiment, the linear actuator (100) increases the effective length of the rod, and hence enables in upward and downward movement of the multi-legged robot (130). It would be appreciated by those skilled in the art, that the linear actuator (100) reduces the effective length of the rod to avoid obstacles.
[0035] The telescopic leg sub-assembly (90) also comprises a foot (120). The leg sub-assembly also comprises a revolute joint (110). The revolute joint (110) is configured to rotate the foot to rotate about the telescopic leg axis.
[0036] In one embodiment, the foot (120) enables in rotations of the robot body in clockwise direction or counter-clockwise direction about the axis of the rod. In one such embodiment, the foot (120) is manufactured with material like rubber and the like. In another embodiment, the revolute joint (110) enables aligning of the foot (120) of the leg assembly (10) of a multi-legged robot in desired orientation.
[0037] Furthermore, in one embodiment, the one or motor assembly (30), the manipulator (80) and the telescopic leg sub-assembly (90) is controlled by microcontroller. In such embodiment, the one or motor assembly (30) and the microcontroller of robot functions together to provide a desired function.
[0038] FIG. 3 is a block diagram representation of an embodiment representing a system to control function of the leg assembly of the robot (150) of FIG. 1 in accordance with an embodiment of the present disclosure. The leg assembly of the robot (10) includes a processing subsystem (160).
[0039] The processing subsystem (160) includes an input receiver module (190). The input receiver module (190) is configured to receive inputs form a user device. In one embodiment, the user device may be a handheld device.
[0040] The processing subsystem (160) also includes a control module (180). The control module (180) is operatively coupled to the input receiver module (190). The control module (180) is configured to control the three degrees of freedom for the robot body along with the robot platform base. A memory subsystem (170) is operatively coupled to the processing subsystem (160). The memory subsystem (170) is configured to store the inputs form the user device. The storing by the memory subsystem (170) comprises of local storage or remote storage.
[0041] In continuation of FIG. 1, the method to control the function of the leg assembly of the robot includes receiving inputs form a user device. In one embodiment, receiving the inputs form the user device includes receiving the inputs form the user device by an input receiver module (190).
[0042] Furthermore, the method to control the function of the leg assembly of the robot also includes controlling the three degrees of freedom for the robot body along with the robot platform base. In one embodiment, controlling the three degrees of freedom for the robot body along with the robot platform base includes controlling the three degrees of freedom for the robot body along with the robot platform base by a control module (180).
[0043] In another exemplary embodiment of multi-legged robot (130) shown in FIG. 4, the links of the parallel manipulator (not shown in FIG. 4) take significantly less bending moment due to ground reaction force. The bending moment occurs along the axis of linear actuator due to the presence of a bearing between the robot platform and the top portion of the linear actuator. In one embodiment, omni-wheels may be used in place of bearings. As used herein, the term “bearing” is a machine element that constrains relative motion to only the desired motion and reduces friction between moving parts. In such embodiment, the omni wheels refer to the disc wheels which may be driven with full force but also may slide laterally with great ease.
[0044] In such embodiment, the vertical force is directly transmitted to the robot platform base (140) as well as to the links of the parallel manipulator. (not shown in FIG. 4) Hence, the leg assembly enables the multi-legged robot (130) to take mainly horizontal forces and moments. (Same as FIG. 5)
[0045] Present disclosure of a leg assembly of a robot provides rigidity with less energy consumption. The energy consumed is less as compared to the conventional approach. The two-motor assembly driving the parallel manipulator significantly spend their forces in propelling the robot forward, backward or sideways instead of working to lift the robot body against gravity.
[0046] Further, the linear actuator reduces the effective length of the rod to avoid obstacles or prevent scraping the ground. Here, the speed of individual leg assembly of the robot or group of leg assemblies of the robot may be controlled separately.
[0047] While specific language has been used to describe the disclosure, any limitations arising on account of the same are not intended. As would be apparent to a person skilled in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein.
[0048] The figures and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, order of processes described herein may be changed and are not limited to the manner described herein. For instance, a serial manipulator may be used instead of a parallel manipulator. Omni-wheels may be used in place of bearings in FIG. 4. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts need to be necessarily performed. Also, those acts that are not dependant on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples.
,CLAIMS:WE CLAIM:
1. A leg assembly of a robot (10), comprising:
a leg frame (20) mechanically coupled to a robot platform base (140), and configured to attach one or more motor assembly (30) with the robot platform base (140);
a manipulator (80) mechanically coupled to the one or more motor assembly (30), and configured to hold a telescopic leg sub-assembly (90);
the telescopic leg sub-assembly (90) mechanically coupled to the manipulator (80), wherein the telescopic leg sub-assembly (90) comprises:
a linear actuator (100);
a foot (120); and
a revolute joint (110), wherein the revolute joint is configured to rotate the foot (120) to rotate about the telescopic leg axis.
2. The leg assembly of the robot (10) as claimed in claim 1, wherein the leg assembly of the robot (10) is fabricated to provide three degrees of freedom for the robot body along with the robot platform base (140).
3. The leg assembly of the robot (10) as claimed in claim 2, wherein the manipulator (80) allows tip or end-effector of the manipulator (80) to move in horizontal plane along x and y axes.
4. The leg assembly of the robot (10) as claimed in claim 2, wherein the linear actuator (100) is configured for upward and downward movement of the robot platform base (140).
5. The leg assembly of the robot (10) as claimed in claim 1, further comprises:
a processing subsystem (160), comprising
an input receiver module (190), and configured to receive inputs form a user device; and
a control module (180) operatively coupled to the input receiver module (190), and configured to control the three degrees of freedom for the robot body along with the robot platform base.

Dated 3rd day of July 2019

Vidya Bhaskar Singh Nandiyal
Patent Agent (IN/PA-2912)
Agent for the Applicant