Gravity compensation joint structure and robot including same

Abstract

In a gravity compensation joint structure and a robot including same, the gravity compensation joint structure includes a rotary joint, a dual link unit, and a coil spring. The rotary joint is mounted on a portion at which a rotary motion is performed. The dual link unit is connected to the rotary joint and includes a first rotary link that rotates about a first axis and a second rotary link that rotates about a second axis different from the first axis. The coil spring rotates about a third axis different from the first axis and the second axis, and provides compensation torque to the rotary joint.

Description

Gravity compensation joint structure and robot including the same

[0001] The present invention relates to a gravity compensation joint structure and a robot including the same, and more specifically, to a gravity compensation joint structure that can be usefully used in the fields of precision instruments and robotics and a robot including the same.

[0002] Recently, industries are facing challenges stemming from labor shortages and a shrinking workforce. These social issues, particularly in the automotive and logistics industries, are rapidly increasing demand for robots capable of performing various tasks in place of humans. This situation is particularly pronounced in countries facing aging populations, where advancements in robotics technology are essential to increasing productivity and efficiency.

[0003] These robots must be designed to perform a variety of complex tasks. To achieve this, they must be able to assume a variety of postures and possess a wide working radius. To meet these requirements, existing robots have been developed with multi-joint configurations. Multi-joint robots possess multiple joints, enabling them to perform complex movements through the movement of each joint.

[0004] However, these multi-joint structures typically have a motor directly connected to each joint, which provides the torque required to move each joint of the robot. Lifting heavy objects or performing precise manipulations requires high torque, which necessitates larger motors. In particular, ankle and knee joints require very large driving forces due to their wide range of motion and the need to move a relatively heavy upper body. Therefore, increasing the size of the motors connected to these joints increases the weight of the entire robot system, which leads to increased energy consumption and reduced mobility. Furthermore, robots equipped with large motors are expensive to manufacture and require complex maintenance.

[0005] Therefore, to solve these problems, the need for a gravity compensation mechanism with a relatively simple structure has arisen to compensate for the required torque of the rotary joint of a robot configured to have various working postures and a wide working radius, thereby enabling the rotary joint to be operated even with a small capacity motor.

[0006] Accordingly, the technical problem of the present invention is conceived from this point, and the purpose of the present invention is to provide a gravity compensation joint structure that can assume high flexibility and various postures, and reduce the overall weight and energy consumption of the robot.

[0007] In addition, another object of the present invention is to provide a robot having the gravity compensation joint structure.

[0008]

[0009] According to one embodiment of the present invention, a gravity compensation joint structure for implementing the above-described object includes a rotary joint, a double link portion, and a coil spring. The rotary joint is mounted on a portion where a rotational motion is performed. The double link portion is connected to the rotary joint and includes a first rotary link that rotates around a first axis, and a second rotary link that rotates around a second axis different from the first axis. The coil spring rotates around a third axis different from the first and second axes, and provides a compensation torque to the rotary joint.

[0010] In one embodiment, the coil spring may further include a pressure link extending through the interior of the coil spring and transmitting torque applied to the rotary joint to the coil spring.

[0011] In one embodiment, in the initial state, the first rotation link and the pressure link extend along a straight line or parallel to each other, and in the state where the rotation joint rotates, the first rotation link and the pressure link can have variable extension directions.

[0012] In one embodiment, the device may further include a connecting link that connects the first rotation link and the pressure link and moves the pressure link according to the rotation of the first rotation link.

[0013] In one embodiment, a portion of the connecting link may extend parallel to the extension direction of the first rotation link.

[0014] In one embodiment, when the rotary joint is rotated, the direction in which the first rotary link and the connecting link rotate and the direction in which the pressure link and the coil spring rotate may be opposite to each other.

[0015] In one embodiment, when the rotary joint is rotated, the coil spring is compressed and can generate a compensation torque for the rotation.

[0016] In one embodiment, the connecting link may include an adjusting screw for adjusting the position of the connecting link, thereby adjusting the range of the compensation torque.

[0017] In one embodiment, the first rotation link and the second rotation link can extend parallel to each other regardless of the rotation of the rotation joint.

[0018] In one embodiment, one end of the coil spring is coupled to the upper sheet, and the upper sheet can rotate about the rotary joint together with the coil spring.

[0019] In one embodiment, the other end of the coil spring is coupled to a preload adjustment support, and the preload adjustment support can control the preload of the coil spring.

[0020] In one embodiment, the rotary joint may be a knee joint or an ankle joint of the robot.

[0021] According to another embodiment of the present invention for implementing the above-described object, a gravity compensation joint structure includes a rotary joint, a single rotary link, a coil spring, a pressure link, and a connecting link. The rotary joint is mounted on a portion where a rotational motion is performed. The single rotary link is connected to the rotary joint and rotates around a first axis. The coil spring rotates around a second axis different from the first axis and provides a compensation torque to the rotary joint. The pressure link extends through the interior of the coil spring and transmits a torque applied to the rotary joint to the coil spring. The connecting link connects the single rotary link and the pressure link, and moves the pressure link according to the rotation of the single rotary link.

[0022] In one embodiment, in the initial state, the single rotary link and the pressure link extend along a straight line or parallel to each other, and in the state where the rotary joint rotates, the first rotary link and the pressure link can have variable extension directions.

[0023] In one embodiment, when the rotary joint is rotated, the direction in which the single rotary link and the connecting link rotate and the direction in which the pressure link and the coil spring rotate may be opposite to each other.

[0024] In one embodiment, when the rotary joint is rotated, the coil spring is compressed and can generate a compensation torque for the rotation.

[0025] In one embodiment, the rotary joint may be a waist joint of the robot.

[0026] According to one embodiment of the present invention for implementing another object of the present invention, a robot performs a predetermined operation and includes a lower part of a robot body, an upper part of a robot body, and a first gravity compensation joint structure. The lower part of the robot body constitutes a lower part of the robot and includes a knee joint or an ankle joint. The upper part of the robot body constitutes an upper part of the robot and includes a waist joint. The first gravity compensation joint structure includes a double link part connected to the knee joint or the ankle joint, and a coil spring connected to the double link part to provide a compensation torque according to rotation of the knee joint or the ankle joint.

[0027] In one embodiment, the dual link portion includes a first rotation link connected to the knee joint or ankle joint and rotating about a first axis, and a second rotation link rotating about a second axis different from the first axis, wherein the first rotation link and the second rotation link can extend parallel to each other regardless of rotation of the knee joint or ankle joint.

[0028] In one embodiment, the invention may further include a second gravity compensation joint structure comprising a single rotation link connected to the lumbar joint, and a coil spring connected to the single rotation link to provide a compensation torque according to the rotation of the lumbar joint.

[0029] According to embodiments of the present invention, the gravity compensation joint structure and the robot having the same can improve the efficiency and performance of the robot, enable the robot to perform sufficient movements even with a small motor, and reduce the driving torque required by the motor by offsetting the influence of gravity applied to the joints of the robot.

[0030] FIG. 1 is a schematic diagram illustrating a robot having a gravity compensation joint structure according to one embodiment of the present invention.

[0031] Figure 2 is a perspective view illustrating the gravity compensation joint structure of Figure 1.

[0032] Figures 3a to 3d are operation diagrams illustrating the operation of the gravity compensation joint structure of Figure 2 in a time series manner.

[0033] FIG. 4 is a front view illustrating a first gravity compensation joint structure included in the gravity compensation joint structure of FIG. 2.

[0034] FIG. 5 is a front view illustrating a gravity torque compensation mechanism in the first gravity compensation joint structure of FIG. 4.

[0035] Fig. 6a is an operation diagram showing an example of a preload adjustment mechanism of the coil spring of Fig. 4.

[0036] FIG. 6b is an operational diagram illustrating an example of a position adjustment mechanism of the connecting link of FIG. 4.

[0037] Fig. 7 is a front view illustrating a second gravity compensation joint structure included in the gravity compensation joint structure of Fig. 2.

[0038] Fig. 8 is a front view illustrating a gravity torque compensation mechanism in the second gravity compensation joint structure of Fig. 7.

[0039] Fig. 9a is an operation diagram showing an example of a preload adjustment mechanism of the coil spring of Fig. 7.

[0040] Figure 9b is an operational diagram illustrating the position adjustment mechanism of the connecting link of Figure 7.

[0041] * Explanation of symbols

[0042] 1: Robot 10: Lower part of robot body

[0043] 11: Knee joint 12: Ankle joint

[0044] 20: Upper part of robot body 21: Waist joint

[0045] 1000: Gravity compensation joint structure

[0046] 1001: First gravity compensation joint structure 1002: Second gravity compensation joint structure

[0047] 100, 200: Rotation joint 110, 210: Motor

[0048] 120: Double link section 121: First rotation link

[0049] 122: Second rotation link 220: Single rotation link

[0050] 130, 230: Coil spring 140, 240: Pressurized link

[0051] 150, 250: Connecting link 151, 251: Adjusting screw

[0052] 160, 260: Upper seat 170, 270: Preload adjustment support

[0053] 171, 271: Inner screw a, a': First axis

[0054] b, b': second axis c: third axis

[0055] The present invention is susceptible to various modifications and takes various forms, and thus embodiments are described in detail herein. However, this is not intended to limit the present invention to a specific disclosed form, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. Similar reference numerals have been used to designate similar components throughout the description of each drawing. While terms such as "first," "second," etc. may be used to describe various components, these components should not be limited by these terms.

[0056] The above terms are used solely for the purpose of distinguishing one component from another. The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprises" or "consists of" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0057] Hereinafter, with reference to the attached drawings, a preferred embodiment of the present invention will be described in more detail.

[0058] FIG. 1 is a schematic diagram illustrating a robot having a gravity compensation joint structure according to one embodiment of the present invention.

[0059] Referring to FIG. 1, the robot (1) in the present embodiment may be a mobile robot, and a mobile robot means a robot that can move autonomously and perform various tasks by utilizing a joint structure such as an actuator and a driving structure such as a wheel.

[0060] These mobile robots can perceive their surroundings through built-in sensors and control systems, plan paths, and move to a target location. Furthermore, they can be equipped with various work tools to transport objects or automatically perform specific tasks. These robots (1) include a lower robot body (10) comprising a lower portion of the robot (1) based on a waist joint (21), an upper robot body (10) including the waist joint (21), and a gravity compensation joint.

[0061] Specifically, the gravity compensation joints may include an ankle joint (11) and a knee joint (12) so that the robot (1) can walk like a human, and a waist joint (21) may be added for more complex movements.

[0062] The above gravity compensation joint includes a gravity compensation joint structure (1000), and the gravity compensation joint structure (100) can be provided in at least one of an ankle joint (11), a knee joint (12), and a waist joint (21).

[0063] That is, the ankle joint (11) and the knee joint (12) of the robot (1) may be provided with a first gravity compensation joint structure (1001) including a rotary joint (100) using a gravity compensation mechanism, as described later, and the waist joint (21) of the robot (1) may be provided with a second gravity compensation joint structure (1002) including a rotary joint (200) using a gravity compensation mechanism, as described later. The robot (1) is configured to have various postures and a wide working radius for work by using such a gravity compensation adjustment mechanism.

[0064] Fig. 2 is a perspective view illustrating the gravity compensation joint structure of Fig. 1. Figs. 3a to 3d are operation diagrams illustrating the operation of the gravity compensation joint structure of Fig. 2 in a time series manner.

[0065] Referring to FIG. 2, the gravity compensation joint structure (1000) is largely composed of a first gravity compensation joint structure (1001) including a rotary joint (100) configured to allow the knee joint (11) and ankle joint (12) of the lower body (10) of the robot (1) to rotate, and a second gravity compensation joint structure (1002) including a rotary joint (200) configured to allow the waist joint (21) of the upper body (20) of the robot (1) to rotate.

[0066] Here, a motor (110) for operating the knee joint (11) or ankle joint (12) and a motor (220) for operating the waist joint (21) are directly connected to each rotary joint (100, 200) to provide the torque required to move each rotary joint (100, 200) of the robot (1).

[0067] Accordingly, the operation of the gravity compensation joint structure (1000) is sequentially performed as follows. First, Fig. 3a illustrates a state in which each rotary joint does not rotate. In this state, when the robot (1) performs a specific task, as in Fig. 3b, first, the ankle joint (12) is rotated using the motor (110) for operating the ankle joint (12), then, as in Fig. 3c, the knee joint (11) is rotated using the motor (110) for operating the knee joint (11), and finally, as in Fig. 3d, the waist joint (21) can be rotated using the motor (220) for operating the waist joint (21).

[0068] However, the motor (110) for operating the knee joint (11) or ankle joint (12) must be able to support the upper body (20) of the robot (1) even when the knee joint (11) or ankle joint (12) rotates, so a very large driving force is required and a very large size may be required.

[0069] Accordingly, the gravity compensation joint structure (1000) according to the present embodiment provides a gravity compensation mechanism for compensating for the required torque of the rotary joint (100, 200) in order to reduce the overall weight of the robot (1) by reducing the size of the motor (110, 220), particularly the motor (100) for operating the knee joint (11) or ankle joint (12).

[0070] FIG. 4 is a front view illustrating a first gravity compensation joint structure included in the gravity compensation joint structure of FIG. 2.

[0071] Referring to Fig. 4, the first gravity compensation joint structure (1001) will be examined in detail. Here, the first gravity compensation joint structure (1001) includes a rotary joint (100) configured to enable the knee joint (11) or ankle joint (12) of the lower body (10) of the robot (1) to rotate, as described above.

[0072] More specifically, referring to FIG. 4, the first gravity compensation joint structure (1001) largely includes a rotary joint (100), a motor (110), a double link (120), a coil spring (130), a pressure link (140), and a connecting link (150).

[0073] First, the rotary joint (100) is configured to allow a specific portion of the lower body (10) of the robot (1) to rotate. In particular, the specific portion may be the thigh or calf portion of the robot (1). In order to rotate the specific portion, the rotary joint (100) may be the knee joint (11) or ankle joint (12) of the robot (1).

[0074] The motor (110) is mounted on the rotary joint (100) as described above and can provide the torque necessary for the knee joint (11) or ankle joint (12) of the robot (1) to operate.

[0075] The double link part (120) includes a first rotation link (121) and a second rotation link (122) configured to allow a specific portion of the lower body (10) of the robot (1) to rotate, and the double link part (120) provides a link mechanism of the rotation joint (100).

[0076] The first rotation link (121) is configured to rotate around the first axis (a) of the rotational joint (100), and the second rotation link (122) is configured to rotate around the second axis (b) of the rotational joint (100). At this time, the second rotation link (122) and the first rotation link (121) are configured to rotate parallel to each other. The second axis (b) and the first axis (a) are each fixed to different positions of the rotational joint (100). The distance at which the first axis (a) and the second axis (b) are spaced apart from each other can be designed to be variously variable, but can be spaced apart by the radius of the rotational joint (100) as illustrated.

[0077] Accordingly, the rotary joint (100) can maintain the position or angle of the upper body (20) of the robot (1) even when the ankle joint (11) or knee joint (12) rotates without affecting other joints as described in FIGS. 3a to 3d.

[0078] The coil spring (130) is configured to compensate for the gravitational torque of the rotary joint (100) of the robot (1). When the rotary joint (100) of the robot (1) is at a specific position, the torque applied to the rotary joint (100) by gravity is called gravitational torque. The coil spring (130) can compensate for this gravitational torque and reduce the burden on the motor (110).

[0079] The coil spring (130) is a configuration that can apply force in a certain direction to the rotary joint (100), and can offset the gravitational torque by being connected to the rotary joint (100) to provide a compensation torque. The coil spring (130) has a certain elasticity and can contract or expand in the longitudinal direction. The toe spring (130) is configured to pivot about a third axis (c) at a different position from the first axis (a) and the second axis (b), which are the rotation axes of the double link portion in the rotary joint (100).

[0080] At this time, it is sufficient if the position of the third axis (c), which is the rotational center axis of the coil spring (130), is designed to be different from the positions of the first axis (a) and the second axis (b), and the position is not limited to a specific position. However, as illustrated, it may be positioned on the outside of the rotary joint (100) as a whole, and may be spaced apart from the first axis (a) by a distance approximately equal to the radius of the rotary joint (100).

[0081] In order to provide stability for the repetitive movement of the coil spring (130) as described above by fixing the coil spring (130) to a specific position, one end of the coil spring (130) may be coupled to an upper seat (160) configured to support the coil spring (130) from above by being positioned at the upper end of the coil spring (130). At this time, various coupling structures such as a fixing pin, a customized slot, and a groove may be used so that the upper end of the coil spring (130) can be stably coupled to the upper seat (160).

[0082] In addition, by using a wear-resistant coating or a low-friction material at the part where the upper sheet (160) and the coil spring (130) come into contact, the friction that occurs when the coil spring (130) is repeatedly contracted and stretched can be reduced, and by designing the shape of the upper sheet (160) to precisely mesh with one end of the coil spring (130), the movement of the coil spring (130) can be controlled and unnecessary friction can be prevented.

[0083] In addition, the other end of the coil spring (130) may be coupled with a preload adjustment support (170) configured to support the coil spring (130) from below by being located at the lower end of the coil spring (130). As described below, the preload adjustment support (170) may be connected to a pressure link (140) by a screw connection, and may be configured to adjust the preload applied to the coil spring (130) by adjusting the screw to contract and extend the coil spring (130) in the longitudinal direction.

[0084] However, the method of coupling between the other end of the coil spring (130) and the preload adjustment support (170) is not limited to a screw coupling, and various coupling methods may be used that can contract or relax the length of the coil spring (130) without the pressure link (140) moving. In addition, by arranging a rotary bushing (not shown) at the part where the preload adjustment support (170) and the coil spring (130) come into contact, friction can be minimized during the process of adjusting the preload, and the life of the coil spring (130) can be extended.

[0085] The pressure link (140) is configured to transmit the gravitational torque applied to the rotary joint (100) to the coil spring (130). The pressure link (140) extends along the center of the coil spring (130) in the same direction as the extension direction of the coil spring (130). Accordingly, the coil spring (130) is positioned to surround the pressure link (140) from the outside, and the structure of the first gravity compensation joint structure (1001) can be designed relatively simply.

[0086] The connecting link (150) is configured to connect the first rotation link (121) and the pressure link (140) to transmit the rotational motion of the first rotation link (121) to the pressure link (140). That is, the point where the connecting link (150) and the pressure link (140) are connected becomes the point of application of the force of the coil spring (130) that generates gravity compensation torque. At this time, the first rotation link (121) and the pressure link (140) in the initial state are aligned in a straight line or in a parallel line in each longitudinal direction, and the connecting link (150) may be configured such that a part of the connecting link (150) is connected between the first rotation link (121) and the pressure link (140) in a manner parallel to the longitudinal direction of the first rotation link (121).

[0087] In this way, the first gravity compensation joint structure (1001) implements a gravity torque compensation mechanism in which the pressure link (140) moves according to the movement of the connecting link (150) due to the rotational movement of the first rotation link (121) to transmit gravity torque to the coil spring (130).

[0088] FIG. 5 is a front view illustrating a gravity torque compensation mechanism in the first gravity compensation joint structure of FIG. 4.

[0089] Referring to FIG. 5, the gravity torque compensation mechanism of the first gravity compensation joint structure (1001) is described.

[0090] First, in order to rotate the rotary joint (100) as much as necessary for a specific task, the first rotary link (121) and the second rotary link (122) are rotated at a specific angle ( ) and a torque due to gravity is generated at the rotary joint (100) while rotating together. At this time, the connecting link (150) connected to the rotary link (121) also rotates at a specific angle ( ) is simultaneously rotated, the pressure link (140) connected to the connecting link (150) is also pulled toward the upper part of the rotary joint (100). At this time, as the pressure link (140) is pulled toward the upper part, the preload adjustment support (170) coupled with the pressure link (140) is also moved. As a result, the coil spring (130) is contracted from the initial length (ℓ₁) to a specific length (ℓ₂) and at the same time rotated at a specific angle ( ) to rotate. In this way, the force stored as the coil spring (130) contracts and rotates compensates for the gravitational torque of the rotary joint (100), thereby reducing the load on the motor (110).

[0091] The gravity torque compensation mechanism of this first gravity torque joint structure (1001) is implemented by using a pressurized link (140) and a coil spring (130), and since it acts in a direction opposite to the applied load based on the rotary joint (100), the structure can be relatively simplified and manufacturing and maintenance can be facilitated.

[0092] In addition, the first gravity torque joint structure (1001) may further include an inner screw (171) configured to adjust the length of the coil spring (130) to adjust the preload, thereby implementing a preload adjustment mechanism of the coil spring (130).

[0093] Specifically, the preload adjustment support (170) is connected to the pressure link (140) by an inner screw (171), and by the rotation of the inner screw (171), the preload adjustment support (170) moves in the longitudinal direction of the coil spring (130), thereby contracting or stretching the coil spring (130) connected to the preload adjustment support (170), thereby adjusting the length of the coil spring (130).

[0094] The inner screw (171) as described above can be adjusted to apply an appropriate preload to the coil spring (130) to provide a desired gravity compensation effect from the initial state of the rotary joint (100) of the robot (1), thereby providing a certain amount of torque in advance even before rotation. In addition, if the rotary joint (100) receives the maximum gravity torque at a specific angle, the preload can be adjusted according to the angle to provide the necessary compensation torque. Through this, the torque generated when the coil spring (130) rotates can be consistently maintained, thereby reducing unexpected torque changes during rotation, and the force generated when the coil spring (130) contracts can be consistently maintained, thereby minimizing energy loss. In particular, a consistent compensation torque can be provided even when the upper load of the robot (1) changes.

[0095] Fig. 6a is an operation diagram showing an example of a preload adjustment mechanism of the coil spring of Fig. 4.

[0096] Referring to Fig. 6a, which illustrates a preload adjustment mechanism of a coil spring (130), in the initial state of the rotary joint (100), the preload adjustment support (170) is moved upward by the rotation of the inner screw (171), thereby reducing the coil spring (130) by a desired length (h1), thereby adjusting the initial preload. For example, if the preload of the coil spring (130) is high, it can rebound with a greater force at the same rotation angle to provide a greater gravity compensation force, and if the preload is low, it can rebound with less force at the same rotation angle to provide a smaller gravity compensation force. Through this, the preload adjustment mechanism of the coil spring (130) can provide a compensation torque under various load conditions of the rotary joint (100).

[0097] FIG. 6b is an operational diagram illustrating an example of a position adjustment mechanism of the connecting link of FIG. 4.

[0098] The first gravity torque joint structure (1001) can implement a position adjustment mechanism of the connection link (150) by further including an adjustment screw (151) configured to adjust the position of the connection link (150). This adjustment screw (151) can manually adjust the position of the connection link (150), thereby adjusting the range for compensating for the initial gravity torque.

[0099] In addition, the first gravity torque joint structure (1001) can implement a position adjustment mechanism of the connection link (150) by combining an actuator (not shown) to adjust the position of the connection link (150). In this case, by adjusting the position of the connection link (150) by the actuator, the range for compensating for gravity torque can be adjusted in real time.

[0100] Specifically, as illustrated in FIG. 6b, in the position adjustment mechanism of the connecting link (150), the length of the connecting link (150) is adjusted by a specific length (h2) in the longitudinal direction of the first rotary link (121) connected thereto through the adjusting screw (151) coupled to the connecting link (150), thereby adjusting the point at which the pressure link (140) and the connecting link (150) are coupled in the initial state. Accordingly, the point of application of the force of the coil spring (130) that generates gravity compensation torque also changes.

[0101] In this way, the position adjustment mechanism of the connecting link (150) is newly adjusted by the adjusting screw (151), and the gravity compensation torque range of the coil spring (130) changes depending on the point at which the initial state pressure link (140) and the connecting link (150) are coupled, so that the initial state gravity compensation torque can be optimized as desired. In addition, as described above, when the length of the connecting link (150) is adjusted by the actuator coupled to the rotary joint (100), the gravity compensation torque range of the coil spring (130) at various angles of the rotary joint (100) can be optimized in real time, thereby increasing the efficiency and stability of the gravity compensation mechanism.

[0102] Fig. 7 is a front view illustrating a second gravity compensation joint structure included in the gravity compensation joint structure of Fig. 2.

[0103] Referring to Fig. 7, a second gravity compensation joint structure (1002) including a rotary joint (200) utilizing a gravity compensation mechanism will be examined in detail. Fig. 7 schematically illustrates a second gravity compensation joint structure (1002) configured to allow a specific portion of the upper body (20) of the robot (1) to rotate, as described above.

[0104] The second gravity compensation joint structure (1002) illustrated in FIG. 7 largely includes a rotary joint (200), a motor (210), a single rotary link (220), a coil spring (230), a pressure link (240), and a connecting link (250).

[0105] First, the rotary joint (200) is configured to allow a specific portion of the upper body (20) of the robot (1) to rotate. In particular, the specific portion may be the upper body or arm portion of the robot (1). In order to rotate the specific portion, the rotary joint (200) may be the waist joint (21) of the robot (1).

[0106] The motor (210) is mounted on the rotary joint (200) as described above and can provide the torque necessary for the waist joint (21) of the robot (1) to operate.

[0107] A single rotary link (220) provides a link mechanism of a rotary joint (200) configured to allow a specific portion of the upper body (20) of the robot (1) to rotate. The single rotary link (220) is configured to rotate about a first axis (a') of the rotary joint (100).

[0108] The coil spring (230) is configured to compensate for the gravitational torque of the rotary joint (200) of the robot (1). When the rotary joint (200) of the robot (1) is at a specific position, the torque applied to the rotary joint (200) by gravity is called gravitational torque. The coil spring (230) can compensate for this gravitational torque and reduce the burden on the motor (210).

[0109] A coil spring (230) is a configuration that can apply force in a certain direction to a rotary joint (200). A coil spring is mainly used, and is connected to a rotary joint (200) to provide a compensation torque, thereby canceling out a gravitational torque. The coil spring (230) can contract or expand in the longitudinal direction, and is also configured to pivot about a second axis (b') at a different position from the first axis (a'), which is the rotation axis of a single rotary link (220) in the rotary joint (200).

[0110] At this time, it is sufficient for the second axis (b') to be at a different position from the first axis (a'), and its position is not limited. However, as illustrated, the second axis (b') may be positioned so as to be spaced apart from the first axis (a') by a distance approximately equal to the radius of the rotary joint (200).

[0111] In order to provide stability for repetitive movements of the coil spring (230) as described above by fixing the coil spring (230) to a specific position, one end of the coil spring (230) may be positioned at the top of the coil spring (230) and may be coupled with an upper sheet (260) configured to support the coil spring (230) from above. At this time, various coupling structures such as a fixing pin, a customized slot, and a groove may be used so that the upper end of the coil spring (230) can be stably coupled to the upper sheet (260), and such coupling structures are not limited thereto.

[0112] In addition, by using a wear-resistant coating or a low-friction material at the part where the upper sheet (260) and the coil spring (230) come into contact, the friction that occurs when the coil spring (230) is repeatedly contracted and stretched can be reduced, and by designing the shape of the upper sheet (260) to precisely mesh with one end of the coil spring (230), the movement of the coil spring (230) can be controlled and unnecessary friction can be prevented.

[0113] In addition, the other end of the coil spring (230) may be coupled with a preload adjustment support (270) configured to support the coil spring (230) from below by being located at the lower end of the coil spring (230). As described below, this preload adjustment support (270) may be connected to a pressure link (240) by a screw connection, and may be configured to adjust the preload applied to the coil spring (230) by adjusting the screw to contract and extend the coil spring (230) in the longitudinal direction.

[0114] However, the coupling method is not limited to screw coupling, and various coupling methods may be used in which the length of the coil spring (230) can be contracted or relaxed without the pressure link (240) moving. In addition, by arranging a rotating bushing (not shown) at the part where the preload adjustment support (270) and the coil spring (230) come into contact, friction can be minimized during the process of adjusting the preload, and the life of the coil spring (230) can be extended.

[0115] The pressurized link (240) is configured to transmit the gravitational torque applied to the rotary joint (200) to the coil spring (230). The pressurized link (240) extends in one direction and penetrates the interior of the coil spring (230), and the coil spring (230) extends while wrapping around the exterior of the pressurized link (240). Through this, the structure of the second gravity compensation joint structure (1002) can be designed relatively simply.

[0116] The connecting link (250) is configured to connect the single rotation link (220) and the pressure link (240) to transmit the rotational motion of the single rotation link (220) to the pressure link (240). That is, the point where the connecting link (250) and the pressure link (240) are connected becomes the point of application of the force of the coil spring (230) that generates gravity compensation torque. At this time, the single rotation link (220) and the pressure link (240) in the initial state are aligned in a straight line or in a parallel line in each longitudinal direction, and the connecting link (250) may be configured such that a part of the connecting link (250) is connected between the single rotation link (220) and the pressure link (240) in a manner parallel to the longitudinal direction of the single rotation link (220).

[0117] In this way, the second gravity compensation joint structure (1002) implements a gravity torque compensation mechanism in which the pressure link (240) moves according to the movement of the connecting link (250) due to the rotational movement of the single rotation link (220) to transmit gravity torque to the coil spring (230).

[0118] Fig. 8 is a front view illustrating a gravity torque compensation mechanism in the second gravity compensation joint structure of Fig. 7.

[0119] Referring to FIG. 8, the gravity torque compensation mechanism of this second gravity compensation joint structure (1002) is described.

[0120] First, to rotate the rotary joint (200) as much as necessary for a specific task, a single rotary link (220) is rotated by a specific angle ( ) and a torque due to gravity is generated at the rotary joint (200). At this time, the connecting link (250) connected to the single rotary link (220) also rotates at a specific angle ( ) are rotated simultaneously, and the pressure link (240) connected to the connecting link (250) is also pulled toward the upper side of the rotary joint (200).

[0121] At this time, as the pressure link (240) is pulled upward, the preload adjustment support (270) coupled with the pressure link (240) is also moved. As a result, the coil spring (230) is contracted from the initial length (ℓ₁) to a specific length (ℓ₂) and at the same time rotated at a specific angle (b') around the second axis (b) of the rotary joint (200). ) to rotate. In this way, the force stored as the coil spring (130) contracts and rotates compensates for the gravitational torque of the rotary joint (100), thereby reducing the load on the motor (110).

[0122] The gravity torque compensation mechanism of this second gravity torque joint structure (1002) is implemented by using a pressurized link (40) and a coil spring (230), and since it acts in a direction opposite to the applied load based on the rotary joint (200), the structure can be relatively simplified and manufacturing and maintenance can be facilitated.

[0123] Additionally, the second gravity torque joint structure (1002) may further include an inner screw (271) configured to adjust the length of the coil spring (230) to adjust the preload, thereby implementing a preload adjustment mechanism of the coil spring (230).

[0124] The inner screw (271) can be adjusted to apply an appropriate preload to the coil spring (230) to provide a desired gravity compensation effect from the initial state of the rotary joint (200) of the robot (1), thereby providing a certain amount of torque even before rotation. In addition, if the rotary joint (200) receives the maximum gravity torque at a specific angle, the preload can be adjusted according to the angle to provide the necessary compensation torque. This makes it possible to consistently maintain the torque generated when the coil spring (230) rotates, thereby reducing unexpected torque changes during rotation, and to consistently maintain the force generated when the coil spring (230) contracts, thereby minimizing energy loss. In particular, consistent gravity compensation can be provided even when the upper load of the robot (1) changes.

[0125] Fig. 9a is an operation diagram showing an example of a preload adjustment mechanism of the coil spring of Fig. 7.

[0126] Referring to Fig. 9a, which shows a preload adjustment mechanism of a coil spring (230), the initial preload can be adjusted by rotating the inner screw (271) of the preload adjustment support (270) in the initial state of the rotary joint (200) to reduce the coil spring (230) to a desired length (h1).

[0127] For example, if the preload of the coil spring (230) is high, it can rebound with a greater force at the same rotation angle, thereby providing a greater gravity compensation force, and if the preload is low, it can rebound with a lesser force at the same rotation angle, thereby providing a smaller gravity compensation force. Through this, the preload adjustment mechanism of the coil spring (230) can provide a constant torque compensation of the rotary joint (200) under various load conditions.

[0128] Figure 9b is an operational diagram illustrating the position adjustment mechanism of the connecting link of Figure 7.

[0129] As illustrated in FIG. 9b, in the second gravity torque joint structure (1002), the connecting link (250) may further include an adjusting screw (251) configured to adjust the position of the connecting link (250), thereby implementing a position adjusting mechanism of the connecting link (250).

[0130] This adjusting screw (251) can manually adjust the position of the connecting link (250), thereby adjusting the range for compensating for the initial gravity torque. Alternatively, the second gravity torque joint structure (1002) may include a separate actuator (not shown). Accordingly, the actuator can implement a position adjustment mechanism for the connecting link (250) that adjusts the position of the connecting link (250). In this case, by adjusting the position of the connecting link (250) by the actuator, the range for compensating for the gravity torque can be adjusted in real time.

[0131] Specifically, referring to Fig. 9b which illustrates a position adjustment mechanism of a connecting link (250), by adjusting the length of the connecting link (250) by a specific length (h2) in the longitudinal direction of the single rotary link (220) connected thereto through an adjusting screw (251) connected to one end of the connecting link (250), the point at which the pressure link (240) and the connecting link (250) are connected in the initial state is also adjusted, so that the point of application of the force of the coil spring (230) which generates gravity compensation torque also changes.

[0132] In this way, the position adjustment mechanism of the connecting link (250) is newly adjusted by the adjusting screw (251), and the gravity compensation torque range of the coil spring (130) changes depending on the point at which the initial state pressure link (140) and the connecting link (150) are coupled, so that the initial state gravity compensation torque can be optimized as desired. In addition, as described above, when the length of the connecting link (250) is adjusted by the actuator coupled to the rotary joint (200), the gravity compensation torque range of the coil spring (230) at various angles of the rotary joint (200) can be optimized in real time, thereby increasing the efficiency and stability of the gravity compensation mechanism.

[0133] According to the embodiments of the present invention described above, the gravity compensation joint structure and the robot having the same can improve the efficiency and performance of the robot, enable the robot to perform sufficient movements even with a small motor, and reduce the driving torque required by the motor by offsetting the influence of gravity applied to the joints of the robot.

[0134] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. A rotary joint mounted on a part where a rotational movement is performed; A dual link portion including a first rotation link connected to the above rotary joint and rotating around a first axis, and a second rotation link rotating around a second axis different from the first axis; and A gravity compensation joint structure that rotates around a third axis different from the first and second axes and includes a coil spring that provides a compensation torque to the rotary joint.

2. In paragraph 1, A gravity compensation joint structure further comprising a pressure link extending through the interior of the coil spring and transmitting torque applied to the rotary joint to the coil spring.

3. In paragraph 2, In the initial state, the first rotation link and the pressure link extend along a straight line or parallel to each other, A gravity compensation joint structure characterized in that, when the above rotary joint is rotated, the first rotary link and the pressure link have variable extension directions.

4. In paragraph 2, A gravity compensation joint structure further comprising a connecting link that connects the first rotation link and the pressure link and moves the pressure link according to the rotation of the first rotation link.

5. In paragraph 4, A gravity compensation joint structure characterized in that a portion of the above connecting link extends parallel to the extension direction of the first rotation link.

6. In the fourth paragraph, when the rotary joint is rotating, A gravity compensation joint structure characterized in that the rotational directions of the first rotation link and the connecting link and the rotational directions of the pressure link and the coil spring are opposite to each other.

7. In the 6th paragraph, when the rotary joint is in a rotating state, A gravity compensation joint structure characterized in that the coil spring is compressed and generates a compensation torque for the rotation.

8. In paragraph 4, the connecting link is A gravity compensation joint structure characterized in that it adjusts the range of the compensation torque, including an adjustment screw for adjusting the position of the above connecting link.

9. In paragraph 1, A gravity compensation joint structure characterized in that the first rotation link and the second rotation link extend parallel to each other regardless of the rotation of the rotation joint.

10. In paragraph 1, One end of the above coil spring is connected to the upper sheet, A gravity compensation joint structure characterized in that the upper sheet rotates about the rotary joint together with the coil spring.

11. In paragraph 1, The other end of the above coil spring is coupled with a preload adjustment support, A gravity compensation joint structure characterized in that the above preload adjustment support controls the preload of the coil spring.

12. In the first paragraph, the rotary joint, A gravity compensation joint structure characterized by being a knee joint or ankle joint of a robot.

13. A rotary joint mounted on a part where a rotational movement is performed; A single rotary link connected to the above rotary joint and rotating around a first axis; A coil spring that rotates around a second axis different from the first axis and provides a compensating torque to the rotary joint; A pressure link extending through the interior of the coil spring and transmitting the torque applied to the rotary joint to the coil spring; and A gravity compensation joint structure including a connecting link that connects the single rotation link and the pressure link and moves the pressure link according to the rotation of the single rotation link.

14. In paragraph 13, In the initial state, the single rotation link and the pressure link extend along a straight line or parallel to each other, A gravity compensation joint structure characterized in that, when the above rotary joint is rotated, the first rotary link and the pressure link have variable extension directions.

15. In the 13th paragraph, when the rotary joint is in a rotating state, A gravity compensation joint structure characterized in that the directions in which the single rotation link and the connecting link rotate and the directions in which the pressure link and the coil spring rotate are opposite to each other.

16. In the 13th paragraph, when the rotary joint is in a rotating state, A gravity compensation joint structure characterized in that the coil spring is compressed and generates a compensation torque for the rotation.

17. In the 13th paragraph, the rotary joint, A gravity compensation joint structure characterized by being a robot's waist joint.

18. In a robot performing a certain action, The lower part of the robot comprises a lower part of the robot body including a knee joint or an ankle joint; The upper part of the robot comprises the upper part of the robot body, including the waist joint; and A robot comprising a first gravity compensation joint structure including a double link portion connected to the knee joint or ankle joint, and a coil spring connected to the double link portion to provide compensation torque according to rotation of the knee joint or ankle joint.

19. In paragraph 18, The above double link portion includes a first rotation link connected to the knee joint or ankle joint and rotating around a first axis, and a second rotation link rotating around a second axis different from the first axis, A robot characterized in that the first rotation link and the second rotation link extend parallel to each other regardless of the rotation of the knee joint or ankle joint.

20. In paragraph 18, A robot further comprising a second gravity compensation joint structure including a single rotation link connected to the lumbar joint, and a coil spring connected to the single rotation link to provide compensation torque according to rotation of the lumbar joint.

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