Rotary caster of a mobile robot, and mobile robot including same

Abstract

According to an embodiment of the present invention, a rotary caster of a mobile robot, in which the rotary caster is mounted on a main frame of the mobile robot, may comprise: a bracket mounted on the bottom of the main frame; a first rotary shaft rotatably mounted on the bracket; a caster frame to which the lower end of the first rotary shaft is fixed and a caster wheel is rotatably mounted; a first encoder mounted on the first rotary shaft to sense the rotational angle of the first rotary shaft; a second rotary shaft that rotates in conjunction with a wheel axle of the caster wheel; and a second encoder mounted on the second rotary shaft to sense the rotational speed of the second rotary shaft.

Description

Rotating caster of a mobile robot and a mobile robot including the same

[0001] The present invention relates to a rotary caster for a mobile robot, and more particularly, to a rotary caster for a mobile robot capable of simultaneously measuring driving speed and steering values ​​while the mobile robot is driving, and a mobile robot including the same.

[0002] In general, a robot is a machine that automatically processes or operates a given task based on its own abilities. It can be broadly classified into mobile robots and fixed robots, and narrowly classified into space-related robots, humanoid robots, industrial robots, biological and medical robots, and network robots.

[0003] Among the above robots, mobile robots are robot systems that have artificial intelligence installed on physical mechanical devices and have autonomous driving capabilities, enabling them to perform tasks that conventional machines, including fixed robots, could not perform in various fields, and also perform some tasks that conventional machines performed more efficiently.

[0004] Looking at examples of mobile robot utilization, automatic guided vehicles (AGVs), a type of mobile robot, have recently been introduced to places such as logistics centers that handle large quantities of products, significantly increasing work productivity and efficiency compared to the past.

[0005] Typical mobile robots use encoders to measure the rotational speed of the left and right driving wheels and monitor their driving speed. However, differential driving, where the rotational speeds of the left and right driving wheels differ, requires different speed controls for steering, making it difficult to define the driving speed of a mobile robot when changing directions.

[0006] Recently, the safety of mobile robots has been enhanced, requiring a dual-function driving speed monitoring system separate from the driving wheel control. Therefore, separate safety encoders have been installed to enhance safety features. However, the driving actuator's compact design, where key components such as the driving wheels, reducer, motor, encoder, and brake are concentrated, posed a challenge for efficient design. Furthermore, monitoring the mobile robot's steering values ​​required the installation of a separate sensor, such as a gyro sensor.

[0007] One embodiment of the present invention provides a rotary caster of a mobile robot and a mobile robot including the same, which can measure the driving speed and steering value of the mobile robot simultaneously by arranging a first encoder and a second encoder on the rotary caster side, thereby clearly defining the driving speed and steering value even when steering the mobile robot.

[0008] In addition, according to one embodiment of the present invention, by arranging a first encoder and a second encoder on the side of the rotary caster to separate them from the driving actuator, thereby implementing a dual driving speed and steering value monitoring device, the safety function of the mobile robot can be strengthened, and a mobile robot including the rotary caster of the mobile robot is provided.

[0009] In addition, according to one embodiment of the present invention, a rotary caster of a mobile robot and a mobile robot including the same are provided, which can reduce component costs by eliminating the need for a separate sensor for measuring steering values ​​of the mobile robot.

[0010] The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned herein will be clearly understood by those skilled in the art from the description below.

[0011] According to one embodiment of the present invention, a rotary caster of a mobile robot mounted on a main frame of the mobile robot may include: a bracket mounted on a lower portion of the main frame; a first rotary shaft rotatably mounted on the bracket; a caster frame having a lower end of the first rotary shaft fixed and a caster wheel rotatably mounted thereon; a first encoder mounted on the first rotary shaft for sensing a rotation angle of the first rotary shaft; a second rotary shaft for rotating in conjunction with the wheel axis of the caster wheel; and a second encoder mounted on the second rotary shaft for sensing a rotational speed of the second rotary shaft.

[0012] The above second rotation axis can be rotatably mounted on the bracket.

[0013] The above wheel axle is mounted on the caster frame, a drive pulley is provided on the wheel axle, a driven pulley is provided at an end of the second rotational shaft, and a drive belt is wound around the drive pulley and the driven pulley to transmit the rotational power of the caster wheel.

[0014] A transmission unit for transmitting driving force may be arranged between the above-mentioned driving pulley and the above-mentioned driven pulley.

[0015] The transmission unit may include a first pulley rotatably mounted on a side of the caster frame; a second pulley mounted to surround the first rotational axis; and a transmission belt wound around the first pulley and the second pulley to transmit the rotational force of the caster wheel.

[0016] The first pulley and the second pulley can be arranged orthogonally to each other.

[0017] The first pulley and the second pulley may each have a double pulley shape in which two of the drive belts and the transmission belt are wound to transmit the rotational power of the caster wheel.

[0018] A switching pulley that allows the transmission belt to be switched by 90 degrees may be placed between the first pulley and the second pulley.

[0019] A mobile robot according to another embodiment of the present invention may include a main frame; a pair of driving wheels each rotatably mounted on a lower portion of the main frame; and a rotating caster mounted on a lower portion of the main frame.

[0020] According to one embodiment of the present invention, by arranging the first encoder and the second encoder on the side of the rotary caster, the driving speed and steering value of the mobile robot can be measured simultaneously, so that the driving speed and steering value can be clearly defined even when steering the mobile robot.

[0021] In addition, according to one embodiment of the present invention, by arranging the first encoder and the second encoder on the side of the rotary caster and separating them from the driving actuator, the safety function of the mobile robot can be strengthened by implementing a dual driving speed and steering value monitoring device.

[0022] Additionally, according to one embodiment of the present invention, a separate sensor for measuring the steering value of a mobile robot is not required, so component costs can be reduced.

[0023] FIG. 1 is a perspective view illustrating a mobile robot according to one embodiment of the present invention.

[0024] FIG. 2 is a perspective view illustrating a rotary caster of a mobile robot according to one embodiment of the present invention.

[0025] Figure 3 is a perspective view of the rotary caster illustrated in Figure 2 from the opposite direction.

[0026] FIG. 4 is a plan view illustrating a rotary caster of a mobile robot according to one embodiment of the present invention.

[0027] FIG. 5 is a front view illustrating a rotary caster of a mobile robot according to one embodiment of the present invention.

[0028] FIG. 6 is a side view illustrating a rotary caster of a mobile robot according to one embodiment of the present invention.

[0029] Figure 7 is a cross-sectional view taken along line AA shown in Figure 6.

[0030] The present invention is susceptible to various modifications and embodiments, and specific embodiments are illustrated and described in detail in the drawings. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. In describing the present invention, detailed descriptions of related known technologies will be omitted if they are deemed to obscure the gist of the present invention.

[0031] Terms such as first, second, etc. may be used to describe various components, but these components should not be limited by these terms. These terms are used solely to distinguish one component from another.

[0032] 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 "has" 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.

[0033] Additionally, throughout the specification, when we say "connected," this does not only mean that two or more components are directly connected, but also that two or more components are indirectly connected through other components, that they are electrically connected as well as physically connected, or that they are referred to by different names depending on location or function but are one.

[0034] Additionally, when described as being formed or arranged "above or below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below," it can include the meaning of a downward direction as well as an upward direction based on one component.

[0035] Hereinafter, a rotary caster of a mobile robot according to the present invention and an embodiment of a mobile robot including the same will be described in detail with reference to the attached drawings. In describing with reference to the attached drawings, identical or corresponding components are assigned the same drawing numbers, and redundant descriptions thereof will be omitted.

[0036] FIG. 1 is a perspective view illustrating a mobile robot according to an embodiment of the present invention, FIG. 2 is a perspective view illustrating a rotary caster of a mobile robot according to an embodiment of the present invention, FIG. 3 is a perspective view illustrating the rotary caster illustrated in FIG. 2 from the opposite direction, FIG. 4 is a plan view illustrating a rotary caster of a mobile robot according to an embodiment of the present invention, FIG. 5 is a front view illustrating a rotary caster of a mobile robot according to an embodiment of the present invention, FIG. 6 is a side view illustrating a rotary caster of a mobile robot according to an embodiment of the present invention, and FIG. 7 is a cross-sectional view taken along line AA illustrated in FIG. 6.

[0037] According to the drawing, in a rotary caster of a mobile robot mounted on a main frame of the mobile robot, the rotary caster may include a bracket (110) mounted on the lower part of the main frame (10), a first rotary shaft (200) rotatably mounted on the bracket (110), a caster frame (120) in which the lower end of the first rotary shaft (200) is fixed and a caster wheel (130) is rotatably mounted, a first encoder (220) mounted on the first rotary shaft (200) to sense a rotation angle of the first rotary shaft (200), a second rotary shaft (300) that rotates in conjunction with the wheel shaft (132) of the caster wheel (130), and a second encoder (320) mounted on the second rotary shaft (300) to sense a rotational speed of the second rotary shaft (300).

[0038] The mobile robot may include a main frame (10), a pair of driving wheels (20) each rotatably mounted on the lower portion of the main frame (10), and a rotating caster (100) mounted on the lower portion of the main frame (10).

[0039] The main frame (10) is formed in a plate shape, and a driving wheel (20) and a rotating caster (100) are mounted on the lower portion of the main frame (10). A wheel frame (22) is mounted upright on both sides of the front lower portion of the main frame (10). In addition, a driving wheel (20) is mounted rotatably on the lower portion of each wheel frame (22).

[0040] A reducer (30), a motor (32), and a driving encoder (34) are installed on the inside of the wheel frame (22). When the motor (32) is driven, the driving encoder (34) measures the rotational speed of the driving wheel (20) and monitors the driving speed. At this time, if differential driving is performed in which the rotational speeds of the driving wheels (20) on both sides are different, it may be difficult to define the driving speed of the mobile robot when changing direction. Therefore, in this embodiment, the rotating caster (100) is applied so that the driving speed and steering value of the mobile robot can be measured simultaneously.

[0041] The rotary caster (100) can be mounted on the lower rear side of the main frame (10). The rotary caster (100) can be connected to the main frame (10) side by a bracket (110) mounted on the lower side of the main frame (10).

[0042] The bracket (110) may have a shape in which the upper portions of the front and rear ends are connected to the lower portion of the main frame (10), and the upper portions of the front and rear ends are extended upright and the lower portions are connected to each other. That is, the bracket (110) may have an approximate 'ㄷ' shape, and a first rotational axis (200) and a second rotational axis (300) may be rotatably mounted on the connected lower portions.

[0043] The first rotation shaft (200) is rotatably mounted on a bracket (110), and the lower end is fixed to a caster frame (120). Therefore, when the caster frame (120) rotates, the first rotation shaft (200) can rotate together with it. A coupling (210) is provided on the upper part of the first rotation shaft (200), and a first encoder (220) is mounted on the upper part. The first encoder (220) serves to sense the rotation angle of the first rotation shaft (200). That is, the first encoder (220) serves to sense the rotation angle of the first rotation shaft (200) and measure the steering value of the mobile robot.

[0044] To explain more specifically, when a mobile robot performs differential driving while driving, for example, when the left driving wheel (20) is controlled to drive faster than the right driving wheel (20), the mobile robot drives while turning to the left. At this time, the caster wheel (130) rotates in conjunction with the driving direction of the driving wheel (20), the first rotation axis (200) rotates by a predetermined angle, and the first encoder (220) senses the rotation angle. That is, since the driving wheel (20) is only controlled for driving speed, it is difficult to sense the rotation angle, and since the actuator on the driving wheel (20) side (consisting of a reducer (30), a motor (32), and a driving encoder (34)) has space constraints, the rotation angle is configured to be sensed on the rotating caster (100) side.

[0045] Inside the caster frame (120), a caster wheel (130) is rotatably mounted on a wheel shaft (132). A drive pulley (140) is provided at one end of the wheel shaft (132). The drive pulley (140) rotates together with the rotation of the caster wheel (130) and transmits rotational power to the driven pulley (330). The driven pulley (330) is provided at an end of the second rotational shaft (300), and is provided at the bottom so as to rotate together with the second rotational shaft (300). A drive belt (150) is wound between the drive pulley (140) and the driven pulley (330) to transmit the rotational power of the caster wheel (130).

[0046] In this embodiment, a transmission unit for transmitting the rotational force of the caster wheel (130) may be placed between the driving pulley (140) and the driven pulley (330). The transmission unit may include a first pulley (400) rotatably mounted on a side of the caster frame (120), a second pulley (410) mounted to surround the first rotational shaft (200), and a transmission belt (420) wound around the first pulley (400) and the second pulley (410) to transmit the rotational force.

[0047] The transmission unit is presented as an example, and the rotational power of the caster wheel (130) can be transmitted only by the drive belt (150) between the drive pulley (140) and the driven pulley (330).

[0048] In this embodiment, when the transmission unit is arranged, the rotational power of the caster wheel (130) can be sequentially transmitted to the drive pulley (140) -> drive belt (150) -> first pulley (400) -> transmission belt (420) -> second pulley (410) -> drive belt (150) -> driven pulley (330).

[0049] Here, the first pulley (400) constituting the transmission unit is arranged on the side of the caster frame (120), and the second pulley (410) is arranged to surround the first rotation axis (200), so that the first pulley (400) and the second pulley (410) are arranged orthogonally to each other. Therefore, in the present embodiment, a switching pulley (430) is arranged to transmit rotational force from the first pulley (400) to the second pulley (410). The switching pulley (430) is rotatably mounted on the upper side of the caster frame (120), and the transmission belt (420) wound between the first pulley (400) and the second pulley (410) can be switched by 90 degrees. Meanwhile, in the present embodiment, the first pulley (400) and the second pulley (410) may each have a dual pulley form in which two belts are wound to transmit rotational force. That is, the drive belt (150) and the transmission belt (420) can be wound in two stages on the first pulley (400) and the second pulley (410), respectively.

[0050] Through the mechanism described above, the rotational force of the caster wheel (130) transmitted from the driving pulley (140) is transmitted to the driven pulley (330), and the second rotational shaft (300) rotates together with the driven pulley (330). At this time, the second rotational shaft (300) rotates as many times as the number of rotations of the caster wheel (130), and the second encoder (320) measures the number of rotations of the caster wheel (130). As a result, the first encoder (220) measures the rotational angle of the caster wheel (130), and at the same time, the second encoder (320) measures the number of rotations of the caster wheel (130), thereby measuring the driving speed and steering value of the mobile robot on the rotational caster (100) side. In addition, if the driving speed and steering value of the mobile robot are measured at the rotational caster (100), a separate gyro sensor, etc., is not required, so the number of parts can be reduced.

[0051] Although the present invention has been described above with reference to specific 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.

[0052] [Explanation of symbols]

[0053] 10: Main frame 20: Driving wheels

[0054] 22: Wheel frame 30: Reducer

[0055] 32: Motor 34: Driving encoder

[0056] 100: Swivel caster 110: Bracket

[0057] 120: Caster frame 130: Caster wheel

[0058] 132: Wheel axle 140: Drive pulley

[0059] 150: Drive belt 200: First rotation shaft

[0060] 210: Coupling 220: First encoder

[0061] 300: Second rotation axis 320: Second encoder

[0062] 330: Driven pulley 400: First pulley

[0063] 410: Second pulley 420: Transmission belt

[0064] 430: Conversion pulley

Claims

1. In the rotary caster of a mobile robot mounted on the main frame of the mobile robot, A bracket mounted on the lower part of the main frame; A first rotary shaft rotatably mounted on the above bracket; A caster frame in which the lower end of the first rotation axis is fixed and a caster wheel is rotatably mounted; A first encoder mounted on the first rotational axis and sensing a rotational angle of the first rotational axis; A second rotary shaft that rotates in conjunction with the wheel axle of the caster wheel; and A rotary caster of a mobile robot including a second encoder mounted on the second rotary axis and sensing the rotational speed of the second rotary axis.

2. In paragraph 1, The second rotation axis is a rotation caster of a mobile robot rotatably mounted on the bracket.

3. In paragraph 2, The above wheel axle is mounted on the above caster frame, A rotary caster of a mobile robot, wherein a drive pulley is provided on the wheel axle, a driven pulley is provided at the end of the second rotary shaft, and a drive belt is wound around the drive pulley and the driven pulley to transmit the rotational power of the caster wheel.

4. In paragraph 3, A rotary caster of a mobile robot in which a transmission unit for transmitting driving force is arranged between the above-mentioned driving pulley and the above-mentioned driven pulley.

5. In paragraph 4, The above transmission unit is, A first pulley rotatably mounted on the side of the caster frame; a second pulley mounted to surround the first rotational axis; and A rotary caster for a mobile robot including a transmission belt that is wound around the first pulley and the second pulley and transmits the rotational force of the caster wheel.

6. In paragraph 5, A rotary caster of a mobile robot in which the first pulley and the second pulley are arranged orthogonally to each other.

7. In paragraph 5, A rotary caster of a mobile robot having a double pulley shape in which the first pulley and the second pulley are each wound with two drive belts and a transmission belt to transmit the rotational power of the caster wheel.

8. In paragraph 6, A rotary caster of a mobile robot, wherein a switching pulley is arranged between the first pulley and the second pulley so that the transmission belt can be switched by 90 degrees.

9. Mainframe; A pair of driving wheels each rotatably mounted on the lower portion of the main frame; and A mobile robot comprising a rotary caster according to any one of claims 1 to 8 mounted on the lower portion of the main frame.

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