Leg assembly and robot including same

Abstract

A leg assembly according to embodiments of the present disclosure comprises: a plurality of actuators including a first actuator and a second actuator; a plurality of legs including a first leg connected to the first actuator and a second leg connected to the second actuator; and a power transmission mechanism connecting the second actuator and the second leg, wherein the power transmission mechanism may comprise: a guide link having a first end connected to the second actuator and movable in a first direction parallel to the longitudinal direction of the first leg; a coupler rotatably connected to each of a second end of the guide link and the second leg; and a linear guide mounted on the first leg, connected to the guide link, and extending in the first direction parallel to the guide link.

Description

Leg assembly and robot including the same

[0001] The present disclosure relates to a leg assembly and a robot including the same.

[0002] Typically, a walking robot comprises a leg assembly comprising multiple joints, such as a scapular joint, a hip joint, and a knee joint, and multiple actuators that drive the multiple joints. Each actuator is located within each joint, with the actuator within the knee joint rotating the knee link, and the actuator within the hip joint rotating the hip link. However, this conventional structure has the problem that the hip joint must support the load of the actuator within the knee joint while driving it. Consequently, the size and weight of the actuator within the hip joint become unnecessarily large.

[0003] To solve this problem, there is a method of positioning the knee actuator adjacent to the hip actuator and transmitting the power of the knee actuator to the knee joint through a separate power transmission mechanism. However, this method also has the problem that the knee actuator is located outside the hip actuator, so the hip actuator has no choice but to bear the load of the knee actuator. For example, referring to FIG. 12 of Patent Document 1 as a prior art, if the motor (402) that moves the knee joint (404) is located outside the hip joint (403), the motor or actuator that moves the hip joint (403) must bear the load of the motor (402) that moves the knee joint (404).

[0004] Furthermore, the four-section link, which transmits the power of the actuator, has relatively high stability, but the combination of multiple links makes it heavy and complex in structure, making assembly and maintenance difficult. Furthermore, belt pulleys have the chronic problem of belt tension, and belt detachment often occurs in high-load and high-impact environments. Even adding a tension pulley cannot fundamentally prevent belt detachment, and the additional gear increases the weight and size of the entire robot, making the structure more complex.

[0005] The above-described information disclosed in the background technology of this invention is only intended to improve understanding of the background of the present invention, and therefore may include information that does not constitute prior art.

[0006] The leg assembly and the robot including the same according to embodiments of the present disclosure can solve the above-described problems, reduce the leg inertia of the leg assembly to reduce the burden on the hip joint, and provide a leg assembly having a robust structure and a robot including the same.

[0007] However, the technical problems to be solved by the embodiments of the present disclosure are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0008] A leg assembly according to embodiments of the present disclosure may include a plurality of actuators including a first actuator and a second actuator, a plurality of legs including a first leg connected to the first actuator and a second leg connected to the second actuator, and a power transmission mechanism connecting the second actuator and the second leg, wherein the power transmission mechanism may include a guide link having a first end connected to the second actuator and movable in a first direction parallel to the longitudinal direction of the first leg, a coupler rotatably connected to a second end of the guide link and the second leg, respectively, and a linear guide mounted on the first leg, connected to the guide link, and extending in the first direction parallel to the guide link.

[0009] The linear guide is attached to the inner surface of the first leg and includes a guide rail extending in the first direction, a guide block moving along the guide rail, and a connecting pin connecting the guide block and the first end of the coupler to the second end of the guide link, the second end of the coupler being connected to the second leg, and the second leg being rotatably connected to the first leg about a pivot axis spaced apart from the second end of the coupler.

[0010] The first leg may include a first support frame connected to the first actuator and a second support frame connected to the first support frame, and the power transmission mechanism may be accommodated in an internal space of the first leg defined within the first support frame and the second support frame, and the first support frame may include a protruding surface that protrudes toward the second leg and includes a pivot shaft to which the second leg is rotatably connected.

[0011] The leg assembly further includes an encoder attached to the first leg adjacent to the power transmission mechanism, wherein the encoder has an encoder head connected to the linear guide and can detect movement of the linear guide while moving in the first direction.

[0012] The first leg includes a first support frame connected to the first actuator and including an inner groove on an inner surface facing the power transmission mechanism, and the encoder can be mounted in the inner groove.

[0013] The above power transmission mechanism includes a second gear located at the end of the guide link and connected to a first gear located on the rotation axis of the second actuator, and the first gear and the second gear can form a bevel gear.

[0014] The second gear includes two second gears positioned at the ends of the guide link and opposite the ends of the guide link, and the first gear and the two second gears are orthogonal, and the rotational axis of the second actuator and the movement axis of the power transmission mechanism can be orthogonal.

[0015] According to embodiments of the present disclosure, a robot includes a plurality of leg assemblies, a main body on which the plurality of leg assemblies are mounted, and a controller accommodated in the main body and controlling the plurality of leg assemblies, wherein the plurality of leg assemblies each include a plurality of actuators including a first actuator and a second actuator, a plurality of legs including a first leg connected to the first actuator and a second leg connected to the second actuator, a power transmission mechanism connecting the second actuator and the second leg, and an encoder attached to the first leg adjacent to the power transmission mechanism, wherein the power transmission mechanism includes a guide link having a first end connected to the second actuator and movable in a first direction parallel to the longitudinal direction of the first leg, a coupler rotatably connected to a second end of the guide link and the second leg, respectively, and a coupler mounted on the first leg and connected to the guide link and movable in the first direction parallel to the guide link. An extending linear guide is included, and the encoder detects the movement of the linear guide while the encoder head is connected to the linear guide and moves in the first direction and transmits the movement to the controller, and the controller can calculate the rotation angle of the second leg based on the movement of the linear guide transmitted from the encoder.

[0016] The first actuator operates the hip joint of the leg assembly and includes a first rotational shaft connected to the first leg, the second actuator operates the knee joint of the leg assembly and includes a second rotational shaft passing through the center of the first actuator and connected to the power transmission mechanism, and the second actuator may be positioned closer to the main body than the first actuator.

[0017] When the first actuator is operated, the first leg rotates and the second leg rotates together with the first leg, and when the second actuator is operated, the power transmission mechanism operates so that the first leg can rotate about the pivot axis with respect to the first leg.

[0018] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other technical effects that are not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0019] A leg assembly and a robot including the same according to embodiments of the present disclosure can reduce the moment of inertia of the leg assembly by positioning a plurality of actuators close to the main body of the robot.

[0020] In addition, by including a structure for converting the rotational movement of the actuator into linear movement in the power transmission mechanism for transmitting power to the knee link, the structure of the power transmission mechanism can be simplified and its size can be reduced.

[0021] In addition to the linear movement of the guide link of the power transmission mechanism itself, the linear guide assists the linear movement of the guide link, thereby enabling the power transmission mechanism to move the second leg more stably.

[0022] Additionally, the encoder is mounted on the hip link rather than the knee link, which can compensate for the structural vulnerability of the knee link by reducing the weight and size of the structurally vulnerable knee link and simplifying the configuration.

[0023] Additionally, the encoder can be arranged parallel to the power transmission mechanism to further ensure the straightness of the power transmission mechanism.

[0024] The following drawings, attached to this specification, illustrate embodiments of the present invention and, together with the description of the invention described below, serve to facilitate understanding of the technical concepts of the present invention. The present invention is not limited to the matters described in the drawings.

[0025] FIG. 1 schematically illustrates a robot including a leg assembly according to embodiments of the present disclosure.

[0026] FIG. 2 is a perspective view of a leg assembly according to embodiments of the present disclosure.

[0027] Figure 3 shows an exploded perspective view of Figure 2.

[0028] Figure 4 shows a plan view of Figure 2.

[0029] FIG. 5 is an enlarged view of a portion of a leg assembly according to embodiments of the present disclosure.

[0030] Figures 6 to 8 illustrate the operation of a leg assembly according to embodiments of the present disclosure.

[0031] A leg assembly according to embodiments of the present disclosure may include a plurality of actuators including a first actuator and a second actuator, a plurality of legs including a first leg connected to the first actuator and a second leg connected to the second actuator, and a power transmission mechanism connecting the second actuator and the second leg, wherein the power transmission mechanism may include a guide link having a first end connected to the second actuator and movable in a first direction parallel to the longitudinal direction of the first leg, a coupler rotatably connected to a second end of the guide link and the second leg, respectively, and a linear guide mounted on the first leg, connected to the guide link, and extending in the first direction parallel to the guide link.

[0032] Embodiments of the present disclosure and methods for achieving them can be more easily understood by referring to the detailed description of the embodiments together with the accompanying drawings. Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the described embodiments can be variously modified and implemented in different forms, and should not be construed as limited to the embodiments described herein. Furthermore, each feature of the various embodiments of the present disclosure can be combined with each other, in whole or in part, and various technically related and operational aspects are possible. Each embodiment can be implemented independently or in combination. The described embodiments are provided as examples so that the present disclosure can be complete and fully convey the spirit of the present disclosure to those skilled in the art. It should be understood that the present disclosure includes all modifications and equivalents, and substitutions are possible within the spirit and technical scope of the present disclosure. Therefore, processes, components, and techniques that are not necessary for a person skilled in the art to fully understand the embodiments of the present disclosure may not be described.

[0033] Unless otherwise specified, the same reference numerals, letters, or combinations thereof throughout the attached drawings and their descriptions represent identical components, and their descriptions are omitted. Furthermore, in describing the embodiments, irrelevant parts may not be depicted in the drawings for clarity.

[0034] The areas depicted in the drawings are schematic and their shapes do not illustrate or limit the actual shape of the device area. The relative sizes of elements, layers, and areas in the drawings may be exaggerated for clarity. Furthermore, the use of hatching and / or shading in the attached drawings may generally serve to clarify boundaries between adjacent elements. Therefore, unless specifically stated otherwise, the presence or absence of hatching or shading does not imply a preference or requirement for any particular material, material properties, dimensions, proportions, commonalities between the illustrated elements, and / or any other characteristics, properties, or characteristics.

[0035] Various embodiments are described herein with reference to cross-sectional examples that are schematic illustrations of embodiments and / or intermediate structures. For example, the shapes of the drawings may vary as a result of manufacturing techniques and / or tolerances. Furthermore, specific structural or functional descriptions disclosed herein are merely examples for illustrating embodiments according to the concepts of the present disclosure. Therefore, the embodiments disclosed herein should be construed as not being limited to the shapes of the illustrated regions, but rather to include variations in shape due to manufacturing processes, etc.

[0036] Specific details may be presented in the specification to facilitate understanding of various embodiments. Alternatively, various embodiments may be practiced without specific details or with one or more of the details. In other cases, well-known structures and devices may be shown in block diagram form to avoid unnecessarily obscuring the various embodiments.

[0037] To facilitate discussion herein, spatially relative terms such as "below," "above," "lower," "top," and the like may be used to describe the relationship of one element or feature to another, as illustrated in the drawings. Spatially relative terms are intended to encompass various orientations of the device in use or operation in addition to the orientations depicted in the drawings. For example, if the device in the drawings were flipped over, another element or feature described as "below" or "lower" would face "above" the other element or feature. Thus, as exemplary terms, "below" and "lower" can encompass both above and below orientations. The device can be oriented in other orientations (e.g., rotated 90 degrees or in other directions), and the spatially relative descriptions used herein should be interpreted accordingly. Similarly, if it is described that a first part is disposed "above" a second part, this means that the first part is disposed above or below the second part.

[0038] Also, the expression "in plan view" means when an object is viewed from above, and the expression "in schematic cross-section" means when a schematic cross-section is taken by cutting the object vertically or horizontally. The term "in side view" means that the first object can be above, below, or to the side of the second object, and vice versa. Additionally, the term "overlapping" or "superimposing" can include layer, laminate, plane, extension, covering, or partially covering, or any other suitable term that a person of ordinary skill in the art would understand and understand. The expression "does not overlap" can include meanings such as "away from" or "spaced from", and any other suitable equivalents that a person of ordinary skill in the art would recognize and understand. The terms "plane" and "surface" can mean that the first object can directly or indirectly face the second object. When a third object is between a first object and a second object, the first object and the second object can be understood as facing each other but indirectly opposing each other.

[0039] When an element, layer, region, or component (hereinafter also referred to as an “element, etc.”) is referred to as being “formed with,” “connected with,” or “coupled to” another element, etc., this includes that it can be formed directly with the element, formed with another element, etc., or indirectly formed with, connected to, or coupled to another element, etc. In addition, “formed with,” “connected with,” or “coupled with” can collectively refer to direct or indirect combinations or connections, or integral or non-integral combinations or connections, of the elements, etc., such that one or more elements, etc. can be present. For example, when an element, etc. is referred to as being “electrically connected with” or “electrically coupled to” another element, etc., this includes that it can be directly electrically connected to or coupled with another element, etc., or that other elements, etc. can be present. However, “direct connection” or “direct coupling” means that one element, etc. is directly connected or coupled to another element, etc., without any intermediate elements, etc., or is present in another element, etc. In addition, when a part of a layer, film, region, guide plate, etc. in the present specification is formed on another part, the formation direction is not limited to the upper direction, and includes the part being formed on the side or bottom. Conversely, when a part of a layer, film, region, guide plate, etc. is formed "under" another part, it includes not only the case where the part is "directly under" the other part, but also the case where there is another part between the part and the other part. Meanwhile, other expressions that describe the relationship of elements, etc., such as "between," "directly between," or "adjacent to" and "directly adjacent to" can be interpreted similarly. In addition, when an element, etc. is mentioned as being between two elements, etc., it can be the only element, etc. between the two elements, etc., or there can be another element, etc. between them.

[0040] Expressions such as "at least one or more" or "either" do not limit the order of the individual elements. For example, expressions such as "at least one of X, Y, and Z," "at least one of X, Y, or Z," or "at least one selected from the group consisting of X, Y, and Z" can include X alone, Y alone, Z alone, or any combination of two or more of X, Y, and Z. Similarly, expressions such as "at least one of A and B" and "at least one of A or B" can include A, B, or A and B. In general, the term "and / or" herein includes any combination of one or more associated list items. For example, expressions such as "A and / or B" can include A, B, or A and B.

[0041] Although terms such as "first," "second," "third," etc. may be used herein to describe various elements, etc., such elements, etc. are not limited by such terms. These terms are used to distinguish one element, etc. from other elements, etc. Accordingly, a first element, etc. described below may be referred to as a second element, etc., without departing from the spirit and scope of the present invention. Describing an element as a "first" element may not require or imply the presence of a second element or other elements. Terms such as "first," "second," etc. may also be used herein to distinguish different categories or sets of elements, etc. For clarity, terms such as "first," "second," etc. may represent "a first category (or first set)," "a second category (or second set)," etc., respectively.

[0042] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present disclosure. As used herein, the singular forms may also include the plural forms, and the plural forms may also include the singular form, unless the context clearly dictates otherwise. The terms "comprise," "include," and "have," when used herein, are meant to specify the presence of specified features, integers, or steps. These expressions do not exclude the presence or addition of one or more other functions, steps, operations, components, and / or groups thereof.

[0043] If one or more embodiments can be implemented differently, a particular process sequence may be performed differently from the order described. For example, two processes described in succession may be performed substantially simultaneously or in the reverse order from the described order.

[0044] The terms "substantially," "about," "approximately," and similar terms are used as terms of approximation, not degree, and imply that the measured or calculated value satisfies the inherent range of variation (e.g., variation due to limitations of the measurement system). For example, "about" could mean within one or more standard deviations, or within ±30%, ±20%, ±10%, or ±5% of the stated value.

[0045] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries, for example, should be interpreted as having a meaning consistent with their meaning in the relevant art and / or the context of this specification, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0046] FIG. 1 schematically illustrates a robot (1) including a leg assembly (10), FIG. 2 illustrates a perspective view of the leg assembly (10), FIG. 3 illustrates an exploded perspective view of FIG. 2, FIG. 4 illustrates a plan view of FIG. 2, FIG. 5 illustrates an enlarged view of a portion of the leg assembly (10), and FIGS. 6 to 8 illustrate the operation of the leg assembly (10).

[0047] The robot (1) is a walking robot that can move around various terrain features using a plurality of leg assemblies (10). The robot (1) can be used for loading and moving people or various types of luggage, or for various service industries such as guidance and navigation. The robot (1) may be a military robot for reconnaissance, surveillance, etc. The robot (1) may be a bipedal walking robot or a quadruped walking robot. Alternatively, the robot (1) may include a different number of leg assemblies (10).

[0048] The robot (1) may include a leg assembly (10), a body (20), a controller (30), and a battery (40).

[0049] The leg assembly (10) is mounted on the robot (1) and receives control signals from the controller (30) and power from the battery (40) to move the robot (1). The leg assembly (10) can rotate around one or more joints to allow the robot (1) to pass over a terrain feature. Details of the leg assembly (10) will be described later.

[0050] The main body (20) can hold and support other components of the robot (1) (e.g., a leg assembly (10), a controller (30), and a battery (40)). The main body (20) accommodates the controller (30) and the battery (40) therein, and a plurality of leg assemblies (10) can be supported by the main body (20). In addition, wiring connecting the plurality of leg assemblies (10) to the controller (30) and the battery (40) can be accommodated inside the main body (20). The main body (20) can include a material having high rigidity (e.g., metal, plastic, etc.). For example, as shown in FIG. 1, the main body (20) can have a rectangular parallelepiped shape with a long side extending in the longitudinal direction of the robot (1) (e.g., the X-axis direction or the first direction of FIG. 1). A plurality of leg assemblies (10) are mounted on each side of the main body (20), and the controller (30) and the battery (40) can be connected to the plurality of leg assemblies (10) by wiring, etc. while being housed inside the main body (20).

[0051] A loading frame (21), a camera (22), and a sensor (23) may be additionally installed on the main body (20). For example, as shown in FIG. 1, the loading frame (21) may be on the upper surface of the main body (20). The loading frame (21) may support cargo when the robot (1) is used to transport cargo, etc. The camera (22) and the sensor (23) are each mounted on the front or bottom of the main body (20), and can detect people or objects around the robot (1) and transmit the detection to the controller (30). The positions and numbers of the cameras (22) and sensors (23) may vary depending on the type, size, purpose, etc. of the robot (1). The camera (22) may include a visible light, infrared, ultraviolet, or thermal imaging camera. The sensor (23) may include an ultrasonic sensor, a laser sensor, an optical sensor, or an electromagnetic sensor.

[0052] The controller (30) is connected to the leg assembly (10), the main body (20), and the battery (40) by wire or wirelessly, and can control the leg assembly (10), the main body (20), and the battery (40). The controller (30) may include a communication device capable of transmitting and receiving data with an external device (e.g., a server or a user terminal) of the robot (1). The controller (30) may control the leg assembly (10), the main body (20), and the battery (40) according to a pre-input program or algorithm. Alternatively, the controller (30) may control the leg assembly (10), the main body (20), and the battery (40) based on a control signal received from a server, a user terminal, or the like.

[0053] The controller (30) can be connected to the encoder (400) wirelessly or wiredly. For example, when the actuator (100) operates and the power transmission mechanism (300) moves, the encoder (400) can move along the power transmission mechanism (300) and transmit information about the movement of the guide link (310) or linear guide (330) to the controller (30). Here, the linear guide (330) moves together with the guide link (310) and is connected to the second leg (220) through the coupler (320), so the controller (30) can interpret the movement of the linear guide (330) or guide link (310) using inverse kinematics to calculate the rotation angle of the coupler (320) and the second leg (220).

[0054] The controller (30) may utilize a direct circuit structure that executes each control function through one or more microprocessors or other control devices, such as memory, processors, logic circuits, look-up tables, etc. The controller (30) may be implemented as a part of a module, program, or code that includes one or more executable instructions for executing a specific logic function. The controller (30) may include or be implemented by a processor, such as a central processing unit, that executes each function or a microprocessor, etc. The controller (30) may include a communication device that can transmit and receive data with an external device, etc. The communication device may include one or more combinations of a digital modem, an RF modem, an antenna circuit, a Wi-Fi chip, and related software and / or firmware.

[0055] The battery (40) can supply power to the leg assembly (10) and the controller (30). The battery (40) is housed inside the main body (20) and can supply power to the leg assembly (10) by receiving a control signal from the controller (30). The leg assembly (10) that receives power from the battery (40) can move the leg (200) as the actuator (100) rotates.

[0056] Alternatively, the robot (1) may be powered from an external power source without a built-in battery (40). For example, the robot (1) may be powered directly from an external source, such as through a charging cable.

[0057] A plurality of leg assemblies (10) are included in the robot (1) and can move the robot (1). For example, the leg assemblies (10) are connected to each of two sides of the robot (1), and four leg assemblies (10) may be included. Fig. 1 shows only one side of the robot (1), and in addition to the two leg assemblies (10) shown on the front of Fig. 1, there may be two leg assemblies (10) on the opposite side of the robot (1). The leg assemblies (10) are connected to the main body (20), controlled by a controller (30), and can operate by receiving power from a battery (40).

[0058] Each leg assembly (10) may be modularized and detachable from the robot (1). For example, the leg assembly (10) may include a plurality of legs (200) and a plurality of actuators (100) that move the plurality of legs (200), and the plurality of actuators (100) and the plurality of legs (200) may be configured as a single module. Therefore, the leg assembly (10) may be more easily detachable from the main body (20) when maintaining, repairing, or replacing it.

[0059] The leg assembly (10) may have some parts included inside the main body (20) and others outside the main body (20). For example, a plurality of actuators (100) included in the leg assembly (10) may be included inside the main body (20) and connected to the controller (30) and the battery (40). A plurality of legs (200) included in the leg assembly (10) may be exposed outside the main body (20).

[0060] The leg assembly (10) may include an actuator (100), a leg (200), a power transmission mechanism (300), and an encoder (400).

[0061] The actuator (100) can receive a control signal from the controller (30) and rotate the leg (200). For example, the actuator (100) can include a motor and a reducer. When the motor of the actuator (100) rotates, the reducer can adjust the amount of torque transmitted to the leg (200) by increasing or decreasing the rotation speed of the motor. The actuator (100) can extend in a second direction intersecting the first direction. For example, as shown in FIG. 2, the central axis AX2 of the first leg (210) among the legs (200) can extend in the first direction, and the central axis AX1 of the actuator (100) can extend in the second direction intersecting (vertically) with the central axis AX2.

[0062] The actuator (100) may include a plurality of actuators (100). The plurality of actuators (100) may be respectively connected to different legs (200). At least some of the plurality of actuators (100) may share the same axis of rotation. For example, at least some of the plurality of actuators (100) may rotate around a central axis AX1.

[0063] For example, the actuator (100) may include a first actuator (110) and a second actuator (120).

[0064] The first actuator (110) operates the hip joint of the leg assembly (10) and can be connected to the first leg (210) among the plurality of legs (200). The first actuator (110) is the actuator (100) closest to the leg (200) among the plurality of actuators (100) and can rotate the first leg (210). For example, as shown in FIGS. 2 and 3, the first actuator (110) is located between the second actuator (120) and the leg (200), and the outer end (e.g., the end on the leg (200) side) of the first rotation axis (111) of the first actuator (110) can be connected to the first leg (210) (e.g., the first support frame (211) located on the inner side of a pair of first support frames (211) of the first leg (210). At least a part of the first actuator (110) can be located inside the main body (20). When the first actuator (110) operates, the first leg (210) rotates, and the second leg (220) connected to the first leg (210) can also rotate together. The first rotation axis (111) of the first actuator (110) may be coaxial with the central axis AX1.

[0065] The second actuator (120) operates the knee joint of the leg assembly (10) and can be connected to the second leg (220) among the plurality of legs (200). The second actuator (120) is located inside the main body (20) relative to the first actuator (110), and is connected to the second leg (220) through the first actuator (110) to rotate the second leg (220). The second rotation axis (121) of the second actuator (120) can pass through the inside of the first actuator (110). For example, as shown in FIG. 3, the second rotation axis (121) of the second actuator (120) can be coaxial with the first rotation axis (111) of the first actuator (110). In addition, the second rotational axis (121) of the second actuator (120) may pass through the center of the first actuator (110) and its end may be connected to the power transmission mechanism (300). The rotation of the second actuator (120) may be transmitted to the second leg (220) through the power transmission mechanism (300). That is, as shown in FIG. 3, the second actuator (120) is closer to the main body (20) than the first actuator (110), and the end of the second rotational axis (121) may protrude outward from the first actuator (110) and pass through the first leg (210) to be connected to the power transmission mechanism (300). Therefore, by reducing the length by which the actuator (100) protrudes outward from the main body (20) (by positioning the actuator (100) closer to the main body (20)), the moment of inertia of the leg assembly (10) can be reduced and the size of the robot (1) can be reduced.

[0066] The second actuator (120) may include a first gear (122). The first gear (122) is provided at an end of the second actuator (120) (e.g., an end on the power transmission mechanism (300) side) and may mesh with the second gear (340) of the power transmission mechanism (300). When the second actuator (120) rotates, the first gear (122) rotates and the second gear (340) of the power transmission mechanism (300) may also rotate. In addition, the second leg (220) may move as the guide link (310) and coupler (320) of the power transmission mechanism (300) move. For example, as shown in FIG. 4, the first gear (122) may be provided at an end of the second rotation shaft (121). The second rotation shaft (121) passes through the first actuator (110) and is inserted into the first leg (210) (first support frame (211)), and the first gear (122) can protrude inside the first leg (210) and be connected to the second gear (340) of the power transmission mechanism (300). For example, the first gear (122) can form a bevel gear together with the second gear (340). The first gear (122) can be arranged vertically with the second gear (340). Therefore, the power transmission efficiency can be increased by employing a bevel gear instead of a conventional low-efficiency worm gear to transmit the power of the second actuator (120) to the second leg (220). In addition, by aligning the rotation axis AX1 of the second actuator (120) and the movement axis AX2 of the power transmission mechanism (300) at right angles, the connection structure of the second actuator (120) and the power transmission mechanism (300) can be simplified and the size reduced.

[0067] The leg (200) is connected to the actuator (100) and can move the robot (1) by being moved by the actuator (100). The leg (200) includes a plurality of legs (200), and each leg (200) can be connected to a different actuator (100).

[0068] For example, the leg (200) may include a first leg (210) and a second leg (220).

[0069] The first leg (210) is connected to the first actuator (110) and can form a hip link. For example, as shown in FIG. 2, the first leg (210) may have a first end connected to the first actuator (110) and a second end connected to the second leg (220). When the first actuator (110) operates, the first leg (210) rotates, and the second leg (220) connected to the first leg (210) can also rotate. The first leg (210) may accommodate a power transmission mechanism (300) therein.

[0070] The first leg (210) may include a first support frame (211) and a second support frame (212).

[0071] The first support frame (211) can hold and support other components of the leg assembly (10), such as the second leg (220), the power transmission mechanism (300), and the encoder (400). The first support frame (211) is connected to the second support frame (212) and can accommodate the power transmission mechanism (300) therein together with the second support frame (212). In addition, the first support frame (211) rotatably supports the second leg (220) and can have an encoder (400) mounted therein.

[0072] The first support frame (211) can be connected to the first actuator (110). For example, the first end of the first support frame (211) is directly connected to the first actuator (110), and when the first actuator (110) rotates, the first support frame (211) rotates, allowing the first leg (210) and the second leg (220) to rotate.

[0073] The first support frame (211) may include a plurality of first support frames (211). For example, as shown in FIG. 3, the first support frame (211) may include two first support frames (211). The two first support frames (211) may face each other, and a power transmission mechanism (300) may be accommodated therebetween. Among the two first support frames (211), the first support frame (211) on the inner side (for example, the first support frame (211) on the main body (20) side) may be connected to the first actuator (110). The linear guide (330) and the encoder (400) of the power transmission mechanism (300) may be mounted on the inner first support frame (211). A second support frame (212) may be connected to the upper and lower surfaces of the two first support frames (211), respectively.

[0074] The first support frame (211) may include an inner groove (2111) and a protruding surface (2112).

[0075] For example, as shown in FIG. 5, the inner groove (2111) may be formed on the inner surface of the first support frame (211) (e.g., the surface facing the power transmission mechanism (300)). The inner groove (2111) may be formed on each of the two first support frames (211) and may have a length corresponding to the power transmission mechanism (300). The power transmission mechanism (300) and the encoder (400) may be mounted on the inner groove (2111). For example, the linear guide (330) and the encoder (400) of the power transmission mechanism (300) may be mounted on the inner groove (2111) of the inner first support frame (211). The inner groove (2111) can secure space so that the power transmission mechanism (300) and the encoder (400) do not interfere with other members when moving without widening the gap between the two first support frames (211). In addition, the linear guide (330) and the encoder (400) of the power transmission mechanism (300) can be stably supported on the first support frame (211).

[0076] The protruding surface (2112) is at an end of the first support frame (211) and can be connected to the second leg (220). For example, as shown in FIG. 6, the protruding surface (2112) is at a second end of the first support frame (211) and can be connected to the second leg (220) with the pivot axis PV as the center. The protruding surface (2112) extends downwardly from the first support frame (211), connects the second leg (220) and the first leg (210), and can protect the connection portion of the second leg (220).

[0077] The second support frame (212) is connected to the first support frame (211) and can accommodate a power transmission mechanism (300) therein together with the first support frame (211). For example, as shown in FIG. 3, the second support frame (212) can include two second support frames (212) connected to the upper and lower surfaces of the two first support frames (211), respectively.

[0078] The second leg (220) can be connected to the second actuator (120) and form a knee link. For example, as shown in FIG. 2, the second leg (220) can have a first end connected to the power transmission mechanism (300) and a second end in contact with the ground. In addition, the second leg (220) can be rotatably connected to the second end of the first leg (210) about a pivot axis PV. The second leg (220) can be connected to the second actuator (120) via the power transmission mechanism (300). When the second actuator (120) rotates, the second rotational axis (121) of the second actuator (120) rotates, thereby causing the power transmission mechanism (300) to move. For example, as the guide link (310) of the power transmission mechanism (300) moves linearly, the coupler (320) connecting the guide link (310) and the second leg (220) can move. Accordingly, the second leg (220) can rotate about the pivot axis PV with respect to the first leg (210).

[0079] When the first actuator (110) operates, the first leg (210) rotates around the rotation axis AX1, and the second leg (220) connected to the first leg (210) and the power transmission mechanism (300) accommodated in the first leg (210) can also move together. When the second actuator (120) operates, the first leg (210) does not move, and the power transmission mechanism (300) and the second leg (220) can move.

[0080] The power transmission mechanism (300) can transmit the power of the actuator (100) to the leg (200). For example, the power transmission mechanism (300) is accommodated in the first leg (210) and connected to the second actuator (120) to transmit the power of the second actuator (120) to the second leg (220).

[0081] The power transmission mechanism (300) may include a guide link (310), a coupler (320), a linear guide (330), and a second gear (340).

[0082] The guide link (310) can receive power from the second actuator (120) and move the second leg (220). For example, the guide link (310) can convert the rotational motion of the second actuator (120) into linear motion. The guide link (310) can move in a linear direction (for example, in the longitudinal direction of the first leg (210), the longitudinal direction of the linear guide (330), or the first direction). A second gear (340) may be provided at a first end of the guide link (310) and connected to the first gear (122) of the second actuator (120). Alternatively, as shown in FIG. 6, a second gear (340) may also be provided at the opposite side of the first end of the guide link (310).

[0083] For example, the guide link (310) may be a ball screw. The guide link (310) may be parallel to the longitudinal direction of the first leg (210) or the longitudinal direction of the linear guide (330). Therefore, instead of a complex gear structure, the ball screw type guide link (310) can stably implement linear motion, thereby driving the second leg (220) with high reproducibility and stability.

[0084] The guide link (310) can be connected to the first leg (210) via the linear guide (330). For example, as shown in FIG. 5, the guide link (310) can be movably connected to the guide rail (331) of the linear guide (330) via the guide block (332) and the connecting pin (333) of the linear guide (330). Therefore, in addition to its own movement, the guide link (310) can move more stably and linearly by the linear guide (330). Therefore, even if vibration or external impact occurs when the robot (1) is moving, the straightness of the guide link (310) can be guaranteed.

[0085] The coupler (320) can connect the guide link (310) and the second leg (220). The coupler (320) has a first end rotatably connected to the second end of the guide link (310), and a second end rotatably connected to the first end of the second leg (220). When the guide link (310) moves, the coupler (320) rotates around the second end of the guide link (310), and the second leg (220) connected to the second end of the coupler (320) can rotate around the pivot axis PV. For example, as shown in FIG. 5, the coupler (320) has a thin piece shape and can be rotatably connected to the second end of the guide link (310) and the guide block (332) via a connecting pin (333).

[0086] The linear guide (330) is mounted on the first leg (210) and can be connected to the guide link (310). The linear guide (330) can move together with the guide link (310) to ensure the straightness of the guide link (310). For example, as shown in FIG. 5, the linear guide (330) can be mounted on the inner groove (2111) of the first support frame (211) located on the inner side. The linear guide (330) can extend in parallel with the longitudinal direction of the first leg (210) or the longitudinal direction of the guide link (310). For example, the linear guide (330) may include a guide rail (331) mounted on an inner groove (2111) of the first support frame (211), a guide block (332) that can move along the guide rail (331), and a connecting pin (333) that connects the guide block (332) and the guide link (310). When the guide link (310) moves, the guide block (332) connected to the guide link (310) through the connecting pin (333) can move along the guide rail (331). The connecting pin (333) can connect the guide link (310), the coupler (320), and the guide block (332) to each other. For example, as shown in FIG. 5, the linear guide (330) may be arranged in a direction perpendicular to the longitudinal direction of the guide link (310) and may be located below the encoder (400).

[0087] The second gear (340) is provided at the end of the guide link (310) and can be connected to the first gear (122) of the second actuator (120). In addition, one more second gear (340) can be provided on the opposite end of the guide link (310) so as to face the end.

[0088] The encoder (400) can detect the position and angle of the second leg (220) by recognizing the movement of the power transmission mechanism (300). For example, the encoder (400) can be mounted on the inner groove (2111) of the first leg (210) adjacent to the linear guide (330). The encoder (400) can detect the movement of the linear guide (330) by moving together when the guide link (310) and the linear guide (330) move and transmit a signal to the controller (30). The encoder (400) is connected to the controller (30) wired or wirelessly, and the controller (30) can interpret the linear movement of the linear guide (330) detected by the encoder (400) using inverse kinematics to calculate the rotation angle of the second leg (220). For example, the encoder (400) is a linear encoder and can move together with the linear guide (330). For example, the encoder (400) may include an encoder rail (420) that is located above the guide rail (331) and extends parallel to the guide rail (331) and an encoder head (410) that moves along the encoder rail (420). The encoder head (410) may be connected to the guide block (332) through a connecting member such as a bolt. Therefore, when the second actuator (120) operates and the guide link (310) moves, the linear guide (330) moves and the encoder head (410) can also move together. In addition, since the linear guide (330) is connected to the coupler (320) which is connected to the second leg (220), when the encoder head (410) detects the movement distance of the linear guide (330), the controller (30) can calculate the rotation angle of the coupler (320) and the second leg (220) based on this.

[0089] As described above, the encoder (400) may be mounted on the first leg (210) corresponding to the hip link, not the second leg (220) corresponding to the knee link. Since the conventional leg assembly has an absolute type encoder installed on the knee link to directly detect the rotation angle of the knee link, the structural vulnerability of the knee link is bound to increase. On the other hand, the leg assembly (10) according to the embodiments of the present disclosure installs the encoder (400) on the first leg (210), thereby simplifying the structure of the second leg (220), reducing its weight, and improving the structural vulnerability of the second leg (220).

[0090] The operation of the leg assembly (10) is as follows.

[0091] In the initial state (or neutral state) where the actuator (100) is not rotating, the position of the leg (200) may be as shown in FIG. 6. However, FIG. 6 is merely an example, and the positions of the first leg (210) and the second leg (220) in the initial state may vary. For example, in the initial state, the first leg (210) may be parallel to the ground. In this state, when the first actuator (110) rotates, the first leg (210) rotates, and the second leg (220) may rotate integrally with the first leg (210).

[0092] Next, when the second actuator (120) rotates, the second rotation shaft (121) of the second actuator (120) rotates, and the power transmission mechanism (300) operates. The guide link (310) converts the rotational motion of the second actuator (120) into a linear motion and moves linearly along the linear guide (330). Then, as the coupler (320) connected to the guide link (310) moves, the second leg (220) rotates around the pivot axis PV. In addition, the encoder (400) connected to the linear guide (330) also moves together. For example, as shown in FIG. 7, as the guide link (310) moves rearward, the second leg (220) rotates clockwise by the coupler (320), and the encoder (400) can move rearward along the linear guide (330). And when the second actuator (120) rotates further, as shown in FIG. 8, the guide link (310) moves further rearward, causing the second leg (220) to rotate further clockwise by the coupler (320), and the encoder (400) can move further rearward along the linear guide (330).

[0093] In this process, the guide link (310) can convert the rotational motion of the second actuator (120) into linear motion as a ball screw. In addition, the linear guide (330) is arranged parallel to the guide link (310), so that the straightness of the guide link (310) can be further ensured. In addition, the encoder (400) connected to the linear guide (330) is also arranged parallel to the guide link (310) and the linear guide (330), so that the straightness of the guide link (310) can be more reliably ensured.

[0094] While the present invention has been described with reference to the embodiments illustrated in the drawings, these are merely examples. Those skilled in the art will readily appreciate that various modifications and equivalent alternative embodiments are possible based on the embodiments described herein. Therefore, the true scope of technical protection of the present invention should be determined based on the appended claims.

[0095] Embodiments of the present disclosure can be used in industries related to leg assemblies and robots including the same.

Claims

1. A plurality of actuators including a first actuator and a second actuator; A plurality of legs including a first leg connected to the first actuator and a second leg connected to the second actuator; and including a power transmission mechanism connecting the second actuator and the second leg; The above power transmission mechanism A guide link having a first end connected to the second actuator and capable of moving in a first direction parallel to the longitudinal direction of the first leg; A coupler rotatably connected to the second end of the guide link and the second leg, respectively; and A leg assembly comprising a linear guide mounted on the first leg, connected to the guide link, and extending in the first direction in parallel with the guide link.

2. In paragraph 1, The above linear guide is A guide rail attached to the inner surface of the first leg and extending in the first direction; a guide block moving along the above guide rail; and A connecting pin connecting the first end of the guide block and the coupler to the second end of the guide link; The second end of the above coupler is connected to the second leg, A leg assembly wherein the second leg is rotatably connected to the first leg about a pivot axis spaced apart from the second end of the coupler.

3. In paragraph 1, The above first leg a first support frame connected to the first actuator; and A second support frame connected to the first support frame; The power transmission mechanism is accommodated in the internal space of the first leg, which is partitioned inside the first support frame and the second support frame, A leg assembly, wherein the first support frame includes a protruding surface that protrudes toward the second leg and includes a pivot axis to which the second leg is rotatably connected.

4. In paragraph 1, The leg assembly further includes an encoder attached to the first leg adjacent to the power transmission mechanism, The above encoder is a leg assembly in which the encoder head is connected to the linear guide and detects the movement of the linear guide while moving in the first direction.

5. In paragraph 4, The first leg includes a first support frame connected to the first actuator and including an inner groove on an inner surface facing the power transmission mechanism, The above encoder is a leg assembly mounted in the inner groove.

6. In paragraph 1, The above power transmission mechanism includes a second gear located at the end of the guide link and connected to the first gear located on the rotation axis of the second actuator, The above first gear and the above second gear constitute a bevel gear, a leg assembly.

7. In paragraph 6, The second gear includes two second gears positioned opposite the end of the guide link and the end of the guide link, The above first gear and the above two second gears are orthogonal, A leg assembly in which the rotation axis of the second actuator and the movement axis of the power transmission mechanism are orthogonal.

8. Multiple leg assemblies; A body on which the plurality of leg assemblies are mounted; and A controller is housed in the main body and controls the plurality of leg assemblies; Each of the above multiple leg assemblies, A plurality of actuators including a first actuator and a second actuator; A plurality of legs including a first leg connected to the first actuator and a second leg connected to the second actuator; A power transmission mechanism connecting the second actuator and the second leg; and An encoder attached to the first leg adjacent to the power transmission mechanism; The above power transmission mechanism A guide link having a first end connected to the second actuator and capable of moving in a first direction parallel to the longitudinal direction of the first leg; A coupler rotatably connected to the second end of the guide link and the second leg, respectively; and A linear guide mounted on the first leg and connected to the guide link and extending in the first direction in parallel with the guide link; The above encoder has an encoder head connected to the linear guide and detects the movement of the linear guide while moving in the first direction and transmits the movement to the controller. A robot in which the controller calculates the rotation angle of the second leg based on the movement of the linear guide received from the encoder.

9. In paragraph 8, The first actuator operates the hip joint of the leg assembly and includes a first rotational axis connected to the first leg, The second actuator includes a second rotational shaft that operates the knee joint of the leg assembly and is connected to the power transmission mechanism through the center of the first actuator, A robot wherein the second actuator is positioned closer to the main body than the first actuator.

10. In paragraph 8, When the first actuator is operated, the first leg rotates and the second leg rotates together with the first leg. A robot in which when the second actuator is operated, the power transmission mechanism is operated so that the first leg rotates about the pivot axis relative to the first leg.

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