Caster and mobile robot having same

Abstract

Embodiments of the present invention provide a caster and a mobile robot having same, the caster allowing the rotation axis of a rotation column and the rotation center of a moving wheel to be positioned on the same line to increase the wheelbase and thus enable a mobile robot to travel stably.

Description

Casters and mobile robots equipped with them

[0001] The present invention relates to a caster that enables stable driving of a mobile robot by increasing the wheel base through a caster that positions the rotational axis of a rotating column and the rotational center of a moving wheel on the same line, and to a mobile robot equipped with the caster.

[0002] Robots have been developed for industrial use to fulfill a portion of factory automation. Recently, the scope of robotics applications has expanded, with developments not only of medical and aerospace robots but also of robots for everyday use.

[0003] Among industrial robots, robots that perform precise assembly work have been developed for automation because they perform the same movements repeatedly and repeat the same movements in a fixed location without any unexpected situations.

[0004] However, the transportation sector, including driving, which requires the ability to assess emergencies, has not yet seen widespread commercialization of robots. However, with the recent advancements in sensors capable of perceiving the surroundings and the advancements in computer power capable of quickly processing and responding to perceived information, the number of autonomous robots is increasing.

[0005] Industrially, robots that perform transportation functions are attracting attention, and competition is intensifying. In addition to robots that transport large or bulky items, there is a growing demand for robots that transport smaller items to their destinations.

[0006] Meanwhile, the robot is equipped with wheels for driving at the bottom, and is generally equipped with a main wheel for moving the robot and a plurality of casters coupled to the corners of the bottom of the robot to control the direction of movement of the robot when the main wheel is driven.

[0007] Here, the caster is aligned during the robot's movement to improve straightness relative to the ground and, at the same time, to facilitate the robot's rotation. To this end, the caster's own rotational axis and the center of rotation of the wheel are not aligned on the same line, but are aligned in a forward-backward direction. This allows the robot's movement to be closely tracked and controlled by the main wheel drive.

[0008] However, since the rotational axis of the caster itself and the rotational center of the wheel are not aligned, the caster is attached at a position facing inward from the lower edge of the robot. This results in a reduction in the wheel base.

[0009] As the wheel base is shortened, the stability of the robot decreases and the robot shakes more when moving or stopping.

[0010] Therefore, a means is required to align multiple casters when the robot moves to improve straightness on the ground, and at the same time, to increase the robot's driving stability by extending the wheel base while making it easy for the robot to rotate.

[0011] The present invention provides a caster and a mobile robot having the same, and more specifically, the purpose is to provide a caster and a mobile robot having the same, which enable stable driving of the mobile robot by increasing the wheel base through a caster that positions the rotational axis of a rotating column and the rotational center of a moving wheel on the same line.

[0012] In addition, the purpose is to provide a caster and a mobile robot equipped with the caster, which can improve shock absorption and ground grip even when moving on an uneven ground by positioning an elastic member that acts as a buffer between a rotating column and a wheel frame.

[0013] The problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0014] A caster is provided, comprising: a rotary column that rotates about a first direction that is an up-and-down direction as an axis of rotation; an intermediate member whose one end is coupled to the rotary column and is arranged to be inclined with respect to the rotation axis of the rotary column; a wheel shaft that is arranged in a second direction that is perpendicular to the first direction; a hinge member that connects the other end of the intermediate member and the wheel shaft; and a movable wheel coupled to the wheel shaft and rotates, wherein a center of rotation of the movable wheel is positioned on the same line as the rotation axis of the rotary column.

[0015] The vertical distance from the rotation axis of the above-mentioned rotary column to the other end of the above-mentioned intermediate member may be less than or equal to the length of the radius of the above-mentioned moving wheel.

[0016] The above intermediate member can be inclined at an angle of 30 degrees or more and 60 degrees or less with respect to the rotation axis of the above rotary column.

[0017] It may include a wheel frame coupled to the center of the wheel shaft; a guide pin coupled while penetrating the wheel frame; and an elastic member positioned on the guide pin and in contact with the rotating column.

[0018] The above hinge member can be rotatably connected to the other end of the intermediate member and the wheel shaft.

[0019] The above rotary column may include an inlet groove into which one end of the elastic member is introduced.

[0020] It includes a fastening member coupled to the upper portion of the above rotary column, and the fastening member may include a bearing coupled to the above rotary column so that the above rotary column rotates.

[0021] The above fastening member may include a screw arranged parallel to the rotation axis of the rotating column.

[0022] The present invention provides a mobile robot comprising: a body including a support plate on a lower surface; a main wheel coupled to the center of the support plate; and a plurality of casters coupled to edges of the support plate and controlling movement of the body, wherein at least one of the plurality of casters comprises: a rotary column rotating about a first direction, which is an up-and-down direction, as an axis; an intermediate member having one end coupled to the rotary column and arranged to be inclined with the rotational axis of the rotary column; a wheel shaft arranged in a second direction perpendicular to the first direction; a hinge member connecting the other end of the intermediate member and the wheel shaft; and a moving wheel coupled to the wheel shaft and rotating, wherein a center of rotation of the moving wheel is positioned on the same line as the rotational axis of the rotary column.

[0023] One side of the above moving wheel may be positioned on the same line as one side of the above support plate.

[0024] The vertical distance from the rotation axis of the above-mentioned rotary column to the other end of the above-mentioned intermediate member may be equal to the radius of the above-mentioned moving wheel.

[0025] It may include a fastening member that is coupled to the upper portion of the above-mentioned rotating column and is fastened to the above-mentioned support plate.

[0026] The above fastening member may include a bearing coupled to the rotary column so that the rotary column rotates; and a screw arranged parallel to the rotation axis of the rotary column.

[0027] The caster according to the present invention and the mobile robot equipped with the caster can enable stable driving of the mobile robot by increasing the wheel base through the caster, which positions the rotational axis of the rotational column and the rotational center of the mobile wheel on the same line.

[0028] Additionally, by positioning an elastic member that acts as a buffer between the rotating column and the wheel frame, shock absorption and ground contact can be improved even when moving on uneven ground.

[0029] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention belongs from the description below.

[0030] FIG. 1 is a diagram illustrating a cloud system based on a 5G network according to one embodiment of the present invention.

[0031] FIG. 2 is a drawing for explaining the configuration of a mobile robot according to one embodiment of the present invention.

[0032] FIG. 3 is a diagram illustrating a robot control system according to one embodiment of the present invention.

[0033] FIG. 4 is a drawing illustrating a body of a mobile robot according to one embodiment of the present invention.

[0034] Figures 5 and 6 are drawings for explaining a conventional caster structure.

[0035] Figure 7 is a perspective view illustrating a caster according to one embodiment of the present invention.

[0036] FIG. 8 is a side view of a caster according to one embodiment of the present invention.

[0037] FIG. 9 is a drawing for explaining the role of an intermediate member coupled to a rotating column in a caster according to one embodiment of the present invention.

[0038] FIG. 10 is a drawing for explaining an elastic member positioned between a rotating column and a wheel frame and serving as a buffer in a caster according to one embodiment of the present invention.

[0039] FIG. 11 is a drawing for explaining an extended wheel base through a caster according to one embodiment of the present invention.

[0040] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components will be given the same reference numbers, and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably only for the convenience of writing the specification, and do not in themselves have distinct meanings or roles. In addition, when describing the embodiments disclosed in this specification, if it is determined that a specific description of a related known technology may obscure the gist of the embodiments disclosed in this specification, a detailed description thereof will be omitted. In addition, the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the attached drawings, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention.

[0041] Terms that include ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0042] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0043] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0044] In this application, terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but should be understood not to exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0045] FIG. 1 is a diagram illustrating a 5G network-based cloud system (1000) according to one embodiment of the present invention. FIG. 2 is a diagram illustrating the configuration of a mobile robot (100) according to one embodiment of the present invention. FIG. 3 is a diagram illustrating a robot control system (200) according to one embodiment of the present invention.

[0046] FIG. 1 illustrates a 5G network-based cloud system (1000) according to one embodiment of the present invention.

[0047] Referring to FIG. 1, a cloud system (1000) may include a mobile robot (100), a mobile terminal (300), a robot control system (200), various devices (400), and a 5G network (500).

[0048] A mobile robot (100) is a robot that transports goods from a starting point to a destination. The mobile robot (100) can move directly from a logistics center to a destination, or it can be loaded onto a vehicle from the logistics center to the vicinity of the goods destination, then unloaded near the destination and moved to the destination.

[0049] In addition, the mobile robot (100) can move items to a destination not only outdoors but also indoors. The mobile robot (100) can be implemented as an AGV (Automated Guided Vehicle), and the AGV can be a transport device that moves by sensors, magnetic fields, vision devices, etc. on the floor.

[0050] A mobile robot (100) according to one embodiment of the present invention may include a storage area for storing items. The storage area may be divided to accommodate various items, and various types of items may be placed in the multiple divided partial storage areas. Accordingly, mixing of items may be prevented.

[0051] The mobile terminal (300) can communicate with the mobile robot (100) via a 5G network (500). The mobile terminal (300) can be a device carried by a user who installs a partition in a storage area to load items, or a device carried by a recipient of loaded items. The mobile terminal (300) can provide information based on images, and the mobile terminal (300) can include mobile devices such as a mobile phone, a smart phone, a wearable device (e.g., a smartwatch, a smart glass, a head mounted display (HMD)).

[0052] The robot control system (200) can remotely control the mobile robot (100) and respond to various requests from the mobile robot (100). For example, the robot control system (200) can perform calculations using artificial intelligence based on requests from the mobile robot (100).

[0053] In addition, the robot control system (200) can set the movement path of the mobile robot (100), and when there are multiple destinations, the robot control system (200) can set the movement order of the destinations.

[0054] The various devices (400) may include a personal computer (PC, 400a), an autonomous vehicle (400b), a home robot (400c), etc. When the mobile robot (100) arrives at the transport destination of the goods, it can directly deliver the goods to the home robot (400c) through communication with the home robot (400c).

[0055] Various devices (400) can be connected wirelessly or wiredly to a mobile robot (100), a mobile terminal (300), a robot control system (200), etc. through a 5G network (500).

[0056] The above-mentioned mobile robot (100), mobile terminal (300), robot control system (200), and various devices (400) are all equipped with 5G modules to transmit and receive data at speeds of 100 Mbps to 20 Gbps (or higher), enabling transmission of large-capacity video files to various devices and minimizing power consumption by operating at low power. However, the transmission speed may be implemented differently depending on the embodiment.

[0057] The 5G network (500) may include a 5G mobile communication network, a local area network, the Internet, etc., and may provide a communication environment for devices with or without wires.

[0058] FIG. 2 is a drawing for explaining the configuration of a mobile robot (100) according to one embodiment of the present invention. The description will be made with reference to FIG. 4, which illustrates a mobile robot (100) according to one embodiment of the present invention.

[0059] A mobile robot (100) may include a body (101, see FIG. 4) including a storage area, and the components described below may be included in the body (101). The mobile robot (100) may include a communication unit (110), an input unit (120), a sensing unit (140), an output unit (150), a driving unit (170), a control unit (180), a memory (185), and a power supply unit (190).

[0060] The components illustrated in FIG. 2 are not essential for implementing a mobile robot (100), and thus the mobile robot (100) described in this specification may have more or fewer components than the components listed above.

[0061] The communication unit (110, Transceiver) may include a wired or wireless communication module capable of communicating with the robot control system (200) of FIG. 1.

[0062] As an optional example, the communication unit (110) may be equipped with modules related to GSM (Global System for Mobile communication), CDMA (Code Division Multi Access), LTE (Long Term Evolution), 5G, WLAN (Wireless LAN), Wi-Fi (Wireless-Fidelity), Bluetooth, RFID (Radio Frequency Identification), Infrared Data Association (IrDA), ZigBee, and NFC (Near Field Communication) communication.

[0063] The input unit (120) may include a user input unit (122) for receiving information from a user. As an optional embodiment, the input unit (120) may include a camera (121) for inputting a video signal and a microphone (123) for receiving an audio signal. Here, the camera (121) or the microphone (123) may be treated as a sensor, and a signal acquired from the camera (121) or the microphone (123) may be referred to as sensing data or sensor information.

[0064] The input unit (120) can obtain input data to be used when obtaining output using learning data and a learning model for model learning. The input unit (120) can also obtain unprocessed input data, in which case the control unit (180) can extract input features as preprocessing for the input data.

[0065] A camera (121) is positioned in front of the mobile robot (100) to detect obstacles ahead, and multiple cameras may be positioned at different angles. A plurality of cameras (121) with different shooting directions may be provided, such as a camera that broadly recognizes the front and a camera that photographs the floor.

[0066] Alternatively, cameras with different functions may be provided. For example, a wide-angle camera, an infrared camera, etc. may be provided. In addition, the camera may serve as a sensing unit (140) to detect surrounding objects.

[0067] The user input unit (122) may be equipped with a button or a touch panel for touch input. Alternatively, user commands may be input remotely via a communication unit (110). In this case, the user input unit (122) may include a personal computer (400) or remote control device separately provided from the mobile robot (100), as illustrated in FIG. 1.

[0068] The user input unit (122) includes all methods for receiving user commands, and thus can recognize user commands through voice recognition. That is, a voice recognition device that analyzes voices collected by a microphone (123) to extract user commands can also function as the user input unit (122).

[0069] The input unit (120) may include a product information input unit, wherein the product information input unit may receive information on the size of the product, weight information, destination information, information on the transport requester, etc. In this case, the product information input unit may include a code reader.

[0070] The sensing unit (140) can obtain at least one of internal information of the mobile robot (100), information about the surrounding environment of the mobile robot (100), and user information using various sensors.

[0071] At this time, the sensing unit (140) may include various types of sensors for recognizing the surroundings for autonomous driving. Representative examples include a distance detection sensor or proximity sensor (141) and a lidar (142).

[0072] The proximity sensor (141) may include an ultrasonic sensor that recognizes nearby objects and determines the distance to the objects based on the time it takes for the emitted ultrasonic waves to return. A plurality of proximity sensors (141) may be provided along the perimeter of the mobile robot (100), and may also be provided on the upper side of the mobile robot (100) to detect obstacles above.

[0073] Lidar (142) is a device that precisely maps its surroundings by emitting laser pulses and receiving the light reflected from surrounding objects. While similar in principle to radar, it utilizes different electromagnetic waves, resulting in different technologies and applications.

[0074] Lasers can damage human eyesight because they use light with a wavelength of 600 to 1000 nm. Lidar (142) uses a longer wavelength and is used to measure not only the distance to a target object, but also its speed and direction, temperature, and the analysis and concentration of surrounding atmospheric substances.

[0075] In addition, the sensing unit (140) according to one embodiment of the present invention may include a light sensor, an acceleration sensor, a magnetic sensor, a gyro sensor, an inertial sensor, an RGB sensor, an infrared sensor, a fingerprint recognition sensor, an ultrasonic sensor, a light sensor, a Hall sensor, etc.

[0076] The output unit (150) can generate output related to visual, auditory, or tactile sensations. The output unit (150) can include an optical output unit that outputs visual information, a display (151), etc., a speaker (152) that outputs auditory information, an ultrasonic output unit that outputs ultrasonic signals belonging to an inaudible frequency, etc., and a haptic module that outputs tactile information.

[0077] The memory (185) stores data that supports various functions of the mobile robot (100). The memory (185) can store a number of application programs (or applications) that run on the mobile robot (100), data for the operation of the mobile robot (100), and commands.

[0078] Additionally, the memory (185) can store information necessary for performing operations using artificial intelligence, machine learning, and artificial neural networks. The memory (150) can store a deep neural network model. The deep neural network model can be used to infer result values ​​for new input data other than training data, and the inferred values ​​can be used as a basis for judgment to perform a certain action.

[0079] The power supply unit (190) can supply power to each component of the mobile robot (100) by receiving external power or internal power under the control of the processor (190). The power supply unit (190) includes a battery, which may be a built-in battery or a replaceable battery. The battery may be charged using a wired or wireless charging method, and the wireless charging method may include a magnetic induction method or a magnetic resonance method.

[0080] The driving unit (170) is a means for moving the mobile robot (100), and may include wheels or legs, and may include a wheel driving unit and a leg driving unit that control the wheels or legs. Referring to FIG. 4, a plurality of wheels provided on the bottom surface of the wheel driving unit can be controlled to move the mobile robot (100) including the body (101).

[0081] The wheel may include a main wheel (171) for driving the mobile robot (100) and an axle on which the wheel rotates, as well as a caster including a main shaft that rotates in conjunction with the body (101), and an auxiliary caster that reinforces support to prevent loaded items from falling during driving.

[0082] The leg drive unit (not shown) can control a plurality of legs to move the body according to the control of the control unit (180). The plurality of legs may correspond to a configuration formed so that the mobile robot (100) can walk or run. The plurality of legs may be implemented as four, but the embodiment is not limited thereto. Referring also to FIG. 4, the plurality of legs may be formed as an integral part by being coupled to the body (101) of the mobile robot (100), or may be implemented in a form that is attachable to and detachable from the body (101).

[0083] The mobile robot (100) can move the body (101) through a driving unit (170) having at least one of the wheel driving unit and / or leg driving unit described above. However, in this specification, an embodiment in which the wheel driving unit is mounted on the mobile robot (100) will be mainly described.

[0084] The control unit (180) is a module that controls the components of the mobile robot (100). The control unit (180) may refer to a data processing device built into hardware that has a physically structured circuit to perform a function expressed by a code or command included in a program.

[0085] As an example of a data processing device built into hardware, it may include processing devices such as a microprocessor, a central processing unit (CPU), a processor core, a multiprocessor, an application-specific integrated circuit (ASIC), and a field programmable gate array (FPGA), but the scope of the present invention is not limited thereto.

[0086] The control unit (180) can collect information through the input unit (120). The input of the input unit (120) may also include a touch input on the display (151). Based on the collected information, the control unit (180) can also transmit the collected information to the mobile terminal (200) illustrated in FIG. 1 through the communication unit (110).

[0087] FIG. 3 is a drawing illustrating a robot control system (200) according to one embodiment of the present invention.

[0088] The robot control system (200) may include an AI server. The AI ​​server may refer to a device that trains an artificial neural network using a machine learning algorithm or utilizes a trained artificial neural network. Here, the robot control system (200) may be comprised of multiple servers to perform distributed processing, and may be defined as a 5G network. In this case, the AI ​​server may be included as part of the mobile robot (100) and perform at least a portion of the AI ​​processing within the mobile robot (100).

[0089] The robot control system (200) may include a communication unit (210), memory (230), a learning processor (240), and a processor (260).

[0090] The communication unit (210) of the robot control system (200) can transmit and receive data with external devices such as a mobile robot (100).

[0091] The memory (230) may include a model storage unit (231). The model storage unit (231) may store a model (or artificial neural network, 231a) being learned or learned through the learning processor (240).

[0092] The learning processor (240) can train an artificial neural network (231a) using learning data. The learning model can be used while mounted on the robot control system (200) of the artificial neural network, or can be mounted on an external device such as a mobile robot (100).

[0093] The learning model may be implemented in hardware, software, or a combination of hardware and software. If part or all of the learning model is implemented in software, one or more instructions constituting the learning model may be stored in memory (230).

[0094] The processor (260) can use a learning model to infer a result value for new input data and generate a response or control command based on the inferred result value.

[0095] Fig. 4 is a drawing illustrating a body (101) of a mobile robot (100) according to one embodiment of the present invention. Figs. 5 and 6 are drawings for explaining a conventional caster structure. And Fig. 7 is a perspective view illustrating a caster (130) according to one embodiment of the present invention.

[0096] Hereinafter, in describing a caster (130) and a mobile robot (100) equipped therewith according to one embodiment of the present invention, the forward and backward directions will be described based on the x-axis direction, the left and right directions will be described based on the y-axis direction, and the up and down directions will be described based on the z-axis direction.

[0097] First, the mobile robot (100) according to one embodiment of the present invention can move through the driving unit (170) located at the lower part of the body (101), as described above with reference to FIG. 2. In addition, the body (101) of the mobile robot (100) can have a box-shaped form, as illustrated in FIG. 4. Referring also to FIG. 11, a support plate (101) can be located on the lower surface of the body (101).

[0098] Referring to FIG. 2, the main wheel (171) constituting the driving unit (170) can be connected to the center of the support plate (101) described above. Then, a motor is connected to directly transmit driving force to the body (101), and the speed of the motor can be adjusted to control the moving speed of the mobile robot (100).

[0099] In a mobile robot (100) according to one embodiment of the present invention, a caster (130) is coupled to a corner of a support plate (101) as illustrated in FIGS. 4 and 11 and can serve to control the movement of the body (101). More specifically, the caster (130) can control the movement direction of the mobile robot (100), or can change the driving direction by adjusting the left and right rotation speed of the main wheel (171). In addition, the body (101) can rotate in place by adjusting the direction of the caster (130), and this type of driving unit (170) can serve to help the mobile robot (100) avoid obstacles and move in a limited space.

[0100] Before explaining a caster (130) according to one embodiment of the present invention, a conventional caster structure will be explained with reference to FIGS. 5 and 6.

[0101] In a conventional caster, a rotating member (20) and a wheel (30) are positioned on a connecting plate (40) located at the bottom of the robot. At this time, in order to improve the straightness of the robot by aligning the wheel (30) in the direction of movement when the robot moves and to facilitate the rotation of the robot, the rotation axis of the rotating member (20) and the rotation center of the wheel (30) must not be located on the same line. That is, the rotation axis of the rotating member (20) and the rotation center of the wheel (30) are positioned spaced apart by d1, as illustrated in (a) of FIG. 5.

[0102] In addition, as the rotating member (20) rotates as shown in (b) of Fig. 5, the wheel (30) also rotates to follow the movement of the robot. Ultimately, the rotation radius of the wheel (30) must be considered as d2.

[0103] And referring to Fig. 6, in order to prevent the possibility of caster damage, the caster should not be positioned beyond the length w1 of the connecting plate (40) located at the bottom of the robot. That is, the caster is connected at a position facing inward from the corner side of the connecting plate (40). Consequently, when considering the rotation radius of the wheel (30) described above through Fig. 5 in the connecting plate (40) having the length w1, the conventional caster structure secures a wheel base of d3.

[0104] As described above, as the wheel base is shortened, the stability of the robot when driving decreases, and the robot shakes significantly during movement or stopping.

[0105] Accordingly, the caster (130) and the mobile robot (100) equipped therewith according to one embodiment of the present invention are intended to enable stable driving of the mobile robot (100) by increasing the wheel base.

[0106] Fig. 7 is a perspective view illustrating a caster (130) according to one embodiment of the present invention. As illustrated in Fig. 7, the caster (130) according to one embodiment of the present invention may include a rotating column (131), an intermediate member (132), a wheel shaft (133), a hinge member (134), and a moving wheel (135).

[0107] Referring to FIG. 4, the rotary column (131) can rotate about a first direction (z-axis direction) that is an up-and-down direction as an axis of rotation. In addition, the intermediate member (132) can be arranged so that one end is coupled to the rotary column (131) and is inclined with respect to the rotation axis of the rotary column (131). The wheel shaft (133) can be arranged in a second direction (y-axis direction) that is perpendicular to the first direction. The hinge member (134) can serve to connect the other end of the intermediate member (132) and the wheel shaft (133). The moving wheel (135) can rotate by being coupled to the wheel shaft (133).

[0108] In addition, a caster (130) according to one embodiment of the present invention may include a wheel frame (136) coupled to the center of a wheel shaft (133), a guide pin (137) coupled while penetrating the wheel frame (136), and an elastic member (138) positioned on the guide pin (137) and in contact with a rotary column (131). In addition, a fastening member (160) coupled to the upper portion of the rotary column (131) may be included. More specific details thereof will be described later.

[0109] Fig. 8 is a side view of a caster (130) according to one embodiment of the present invention. Fig. 9 is a drawing for explaining the role of an intermediate member (132) coupled to a rotary column (131) in a caster (130) according to one embodiment of the present invention. Fig. 10 is a drawing for explaining an elastic member (138) positioned between a rotary column (131) and a wheel frame (136) in a caster (130) according to one embodiment of the present invention and serving as a buffer. And Fig. 11 is a drawing for explaining a wheel base extended through a caster (130) according to one embodiment of the present invention.

[0110] As described above through FIG. 7, a caster (130) according to one embodiment of the present invention may include a rotary column (131) that rotates in a first direction (z-axis direction) that is an up-and-down direction, an intermediate member (132) that is coupled at one end to the rotary column (131) and arranged to be inclined with respect to the rotation axis of the rotary column (131), a wheel shaft (133) that is arranged in a second direction (y-axis direction) that is perpendicular to the first direction, a hinge member (134) that connects the other end of the intermediate member (132) and the wheel shaft (133), and a movable wheel (135) that is coupled to the wheel shaft (133) and rotates.

[0111] In particular, the caster (130) according to one embodiment of the present invention can position the rotation center of the moving wheel (135) and the rotation axis of the rotation column (131) on the same line in order to improve the conventional caster structure as described above and increase the wheel base. This can be implemented through an intermediate member (132) arranged to be inclined with respect to the rotation axis of the rotation column (131).

[0112] First, referring to FIG. 9, the intermediate member (132) is arranged to be inclined with respect to the rotation axis of the rotary column (131), thereby transmitting the force (F) due to the load when the mobile robot (100) moves to form an inclination angle with respect to the ground (10). Accordingly, the component (Fx) of the force directed forward (x-axis direction) and the component (Fz) of the force directed toward the ground (10) are transmitted to the moving wheel (135).

[0113] Accordingly, the caster (130) according to one embodiment of the present invention can have a straight line by positioning the rotation axis of the rotary column (131) and the rotation center of the moving wheel (135) on the same line, while allowing the moving wheel (135) to have a ground contact force with respect to the ground (10), and at the same time, aligning the moving wheel (135) toward the front.

[0114] And referring to FIG. 8 together, in a caster (130) according to one embodiment of the present invention, the vertical distance (d4) from the rotation axis of the rotary column (131) to the other end of the intermediate member (132) may be less than or equal to the length of the radius (r) of the moving wheel (135). This is to position the other end of the intermediate member (132) so as not to exceed the size of the moving wheel (135). And through this, damage to the caster (130) can be prevented.

[0115] In addition, the angle (a) at which the intermediate member (132) is tilted relative to the rotation axis of the rotary column (131) may be 30 degrees or more and 60 degrees or less. This is to position the intermediate member (132) tilted relative to the rotation axis of the rotary column (131) in accordance with the size of the moving wheel (135), and to effectively transmit the component (Fx) of the force directed forward and the component (Fz) of the force directed toward the ground (10) described above through FIG. 9 to the moving wheel (135).

[0116] Accordingly, as illustrated in FIG. 11, the caster (130) according to one embodiment of the present invention may have the rotation axis of the rotary column (131) and the rotation center of the moving wheel (135) positioned on the same line, and one side of the moving wheel (135) may be positioned on the same line as one side of the support plate (101). Through this, the moving wheel (135) may secure a wheel base of d5 without exceeding the length w2 of the support plate (101).

[0117] Ultimately, compared to the conventional caster structure described above with reference to FIG. 6, the wheel base can be increased. That is, d5 illustrated in FIG. 11 is longer than d3 illustrated in FIG. 6. Therefore, the mobile robot (100) equipped with the caster (130) according to one embodiment of the present invention can drive more stably by securing a sufficient wheel base.

[0118] FIG. 10 is a drawing for explaining an elastic member (138) positioned between a rotary column (131) and a wheel frame (136) and acting as a buffer in a caster (130) according to one embodiment of the present invention. More specifically, FIG. 10 (a) is a drawing illustrating a caster (130) in the case of a flat ground (10), and FIG. 10 (b) is a drawing illustrating a caster (130) in the case of an uneven ground (10).

[0119] Referring to FIG. 7 together, a caster (130) according to one embodiment of the present invention may include a wheel frame (136) coupled to the center of a wheel shaft (133), a guide pin (137) coupled while penetrating the wheel frame (136), and an elastic member (138) positioned on the guide pin (137) and in contact with a rotary column (131). At this time, the hinge member (134) may be rotatably coupled to the other end of the intermediate member (132) and the wheel shaft (133). In addition, the rotary column (131) may include an insertion groove (139) into which one end of the elastic member (138) is inserted.

[0120] According to one embodiment of the present invention, the caster (130) can compress the elastic member (138) by the rotation of the hinge member (134) and the wheel frame (136) when passing over an uneven ground (10) as illustrated in FIG. 10 (b). In addition, the compression of the elastic member (138) can alleviate impact. In addition, since the ground contact force of the moving wheel (135) can be improved even on an uneven ground (10), stable driving of the mobile robot (100) can be enabled.

[0121] In addition, referring to FIG. 7, a caster (130) according to one embodiment of the present invention may include a fastening member (160) coupled to the upper portion of a rotary column (131). In addition, the fastening member (160) may include a bearing (161) coupled to a rotary column (131) so that the rotary column (131) rotates, as illustrated in FIG. 10 (a). Here, the bearing (161) may include a ball bearing structure having a ball (163) for smooth rotation of the rotary column (131).

[0122] In addition, referring to FIG. 7 and FIG. 11 together, the fastening member (160) of the caster (130) according to one embodiment of the present invention may include a screw (162) arranged parallel to the rotation axis of the rotation column (131). In addition, the caster (130) may be stably coupled to the support plate (101) through the screw (162).

[0123] In summary, the caster according to the present invention and the mobile robot equipped with the caster can increase the wheel base by positioning the rotational axis of the rotating column and the rotational center of the moving wheel on the same line, thereby enabling stable movement of the mobile robot. In addition, by positioning an elastic member that acts as a buffer between the rotating column and the wheel frame, shock absorption and ground grip can be improved even when moving on an uneven surface.

[0124] The above detailed description should not be construed as limiting in any respect and should be considered illustrative only. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are intended to be included within the scope of the present invention.

Claims

1. A rotating column that rotates around the first direction, which is the up-down direction; An intermediate member which is connected to the above-mentioned rotary column and arranged to be inclined with respect to the rotational axis of the above-mentioned rotary column; A wheel shaft arranged in a second direction perpendicular to the first direction; A hinge member connecting the other end of the above intermediate member and the wheel shaft; and It includes a moving wheel that is coupled to the wheel shaft and rotates, The center of rotation of the above moving wheel is, A caster positioned on the same line as the rotation axis of the above rotating column.

2. In paragraph 1, The vertical distance from the rotation axis of the above rotary column to the other end of the intermediate member is, A caster characterized in that the length is less than or equal to the radius of the above moving wheel.

3. In paragraph 1, The above intermediate member is, A caster characterized by being inclined at an angle of 30 degrees or more and 60 degrees or less with respect to the rotation axis of the above-mentioned rotary column.

4. In paragraph 1, A wheel frame coupled to the center of the above wheel shaft; A guide pin coupled through the wheel frame; and A caster characterized by including an elastic member positioned on the above guide pin and in contact with the above rotary column.

5. In paragraph 4, The above hinge member, A caster characterized in that the other end of the intermediate member is rotatably connected to the wheel shaft.

6. In paragraph 5, The above rotating column, A caster characterized by including an introduction groove into which one end of the elastic member is introduced.

7. In paragraph 1, Including a fastening member coupled to the upper part of the above rotating column, The above fastening member is, A caster characterized by including a bearing coupled with the rotary column so that the rotary column rotates.

8. In paragraph 7, The above fastening member is, A caster characterized by including a screw arranged parallel to the rotation axis of the rotating column.

9. A body including a support plate on the lower surface; A main wheel coupled to the center of the above support plate; and It comprises a plurality of casters which are connected to the corners of the above support plate and control the movement of the above body, At least one of the above multiple casters, A rotary column that rotates around the first direction, which is the up-down direction; An intermediate member which is connected to the above-mentioned rotary column and arranged to be inclined with respect to the rotational axis of the above-mentioned rotary column; A wheel shaft arranged in a second direction perpendicular to the first direction; A hinge member connecting the other end of the above intermediate member and the wheel shaft; and It includes a moving wheel that is coupled to the wheel shaft and rotates, The center of rotation of the above moving wheel is, A mobile robot positioned on the same line as the rotation axis of the above rotating column.

10. In paragraph 9, One side of the above moving wheel is, A mobile robot characterized by being positioned on the same line as one side of the above support plate.

11. In paragraph 9, The vertical distance from the rotation axis of the above rotary column to the other end of the intermediate member is, A mobile robot characterized by having a radius equal to that of the above moving wheel.

12. In paragraph 9, A mobile robot characterized by including a fastening member coupled to the upper portion of the above-mentioned rotating column and fastened to the above-mentioned supporting plate.

13. In paragraph 12, The above fastening member is, A bearing coupled with the rotary column so that the rotary column rotates; and A mobile robot characterized by including a screw arranged parallel to the rotation axis of the above-mentioned rotation column.

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