Mobile robot

Abstract

This mobile robot comprises: a body; a pair of front driving wheels installed at a front portion of the body; a pair of rear driving wheels installed at a rear portion of the body; four auxiliary wheels installed on a lower surface of the body; and a wheel variable device for changing the pair of front driving wheels and the pair of rear driving wheels to one of a four-wheel mode and a two-wheel mode. In the four-wheel mode, the pair of front driving wheels and the pair of rear driving wheels are in contact with a traveling surface, and the four auxiliary wheels are spaced apart from the traveling surface. In the two-wheel mode, the pair of front driving wheels are spaced apart from the traveling surface, and the pair of rear driving wheels move to the center of the body, so that the pair of rear driving wheels and the four auxiliary wheels come into contact with the traveling surface.

Description

mobile robot

[0001] The present disclosure relates to a mobile robot, and more particularly, to a mobile robot that can drive by selectively switching between a two-wheel mode and a four-wheel mode.

[0002] With the advancement of robotics technology, mobile robots are being widely used in various fields such as manufacturing, logistics, and service.

[0003] The mobile robot may include an outdoor mobile robot for outdoor driving and an indoor mobile robot for indoor driving.

[0004] Because outdoor environments require relatively large, uneven surfaces, outdoor mobile robots typically incorporate a large support polygon and four drive wheels. Therefore, outdoor mobile robots can utilize the driving force of these four drive wheels to navigate safely outdoors.

[0005] Because indoor spaces are narrow and complex, indoor mobile robots typically feature small support polygons and two drive wheels capable of rotating in place. Therefore, indoor mobile robots can navigate narrow and complex indoor spaces.

[0006] A mobile robot according to one or more embodiments of the present disclosure includes: a body; a pair of front driving wheels installed at a front portion of the body; a pair of rear driving wheels installed at a rear portion of the body; four auxiliary wheels installed at a lower surface of the body; a front wheel variability device including a front linear actuator installed at an upper portion of the body; and a rear wheel variability device including a rear linear actuator installed at a lower portion of the body. The front wheel variability device and the rear wheel variability device include a wheel variability device that changes the pair of front driving wheels and the pair of rear driving wheels into one of a four-wheel mode and a two-wheel mode. In the four-wheel mode, the pair of front driving wheels and the pair of rear driving wheels contact a running surface and the four auxiliary wheels are spaced apart from the running surface. In the above two-wheel mode, the pair of front drive wheels are spaced from the running surface, the pair of rear drive wheels are moved toward the center of the body, and the pair of rear drive wheels and the four auxiliary wheels are in contact with the running surface.

[0007] The front wheel variable device may be formed to move the pair of front drive wheels up and down with respect to the body, and the rear wheel variable device may be formed to move the pair of rear drive wheels forward and backward with respect to the body.

[0008] The above front linear actuator can be configured to move the pair of front driving wheels up and down.

[0009] The front wheel variable device may further include an upper arm having one end connected to the front linear actuator and the other end connected to the pair of front driving wheels; and a lower arm having one end connected to the lower portion of the body and the other end connected to the pair of front driving wheels.

[0010] The above-described front linear actuator may include a front motor; a front screw rotated by the front motor; and a front nut screw-connected to the front screw and to which one end of the upper arm is connected. When the front motor rotates, one end of the upper arm can move linearly along the front screw.

[0011] The upper arm may include a suspension.

[0012] The above suspension may include coil springs and shock absorbers.

[0013] The above rear linear actuator can be configured to move the pair of rear driving wheels back and forth with respect to the body.

[0014] The body may include an upper support plate; a lower support plate installed below the upper support plate; and an inclined block installed on an upper surface of the lower support plate and including an inclined surface. The rear linear actuator may be installed on the inclined surface of the inclined block.

[0015] The above rear wheel variable device may further include a support bar having one end connected to the rear linear actuator and the other end connected to the pair of rear driving wheels.

[0016] The rear linear actuator may include a rear motor; a rear screw rotated by the rear motor; and a rear nut screw-connected to the rear screw and connected to the support bar. When the rear motor rotates, the support bar can move linearly along the rear screw.

[0017] The above rear wheel variable device may include: a fixed plate installed on the rear linear actuator; a movable plate installed parallel to the fixed plate and spaced apart from the fixed plate by a predetermined distance, on which the pair of rear driving wheels are installed; an upper link having one end rotatably installed on the fixed plate and the other end rotatably installed on the movable plate; a lower link installed below the upper link, having one end rotatably installed on the fixed plate and the other end rotatably installed on the movable plate; and a coil spring disposed between the upper link and the lower link.

[0018] The rear wheel variable device may include a fixed plate installed on the rear linear actuator; a moving plate installed at a predetermined distance from the fixed plate and parallel to the fixed plate, and on which one of the pair of rear driving wheels is installed; and a suspension installed between the moving plate and the fixed plate.

[0019] The above pair of front drive wheels and the above pair of rear drive wheels may each include an in-wheel motor.

[0020] Each of the above four auxiliary wheels can be formed as an omni wheel.

[0021] The above-described and other aspects, features, and advantages of the embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings. In the accompanying drawings:

[0022] FIG. 1 is a side view illustrating a mobile robot according to one or more embodiments of the present disclosure.

[0023] FIG. 2 is a plan view illustrating the mobile robot of FIG. 1 according to one or more embodiments of the present disclosure.

[0024] FIG. 3 is a side view showing a state in which the mobile robot of FIG. 1 is switched to a two-wheel mode according to one or more embodiments of the present disclosure.

[0025] FIG. 4 is a perspective view showing a mobile robot according to one or more embodiments of the present disclosure.

[0026] FIG. 5 is a side view showing the mobile robot of FIG. 4 according to one or more embodiments of the present disclosure.

[0027] FIG. 6 is a front view showing the mobile robot of FIG. 4 according to one or more embodiments of the present disclosure.

[0028] FIG. 7 is a rear view showing the mobile robot of FIG. 4 according to one or more embodiments of the present disclosure.

[0029] FIG. 8 is a plan view of the mobile robot of FIG. 4 with the upper support plate removed according to one or more embodiments of the present disclosure.

[0030] FIG. 9 is a perspective view showing a front linear actuator of a mobile robot according to one or more embodiments of the present disclosure.

[0031] FIG. 10 is a perspective view showing a rear linear actuator of a mobile robot according to one or more embodiments of the present disclosure.

[0032] FIG. 11A is a partial diagram showing a left support bar of a rear wheel variable device of a mobile robot according to one or more embodiments of the present disclosure.

[0033] FIG. 11b is a partial diagram showing a left support bar of a rear wheel variable device when the rear drive wheel of a mobile robot according to one or more embodiments of the present disclosure is raised.

[0034] FIG. 11c is a partial diagram showing a left support bar of a rear wheel variable device when the rear drive wheel of a mobile robot according to one or more embodiments of the present disclosure is lowered.

[0035] FIG. 12 is a partial diagram showing a left support bar of a rear wheel variable device of a mobile robot according to one or more embodiments of the present disclosure.

[0036] FIG. 13 is a perspective view showing an auxiliary wheel of a mobile robot according to one or more embodiments of the present disclosure.

[0037] FIG. 14 is a side view of the auxiliary wheel of FIG. 13 according to one or more embodiments of the present disclosure.

[0038] FIG. 15 is a perspective view showing a mobile robot according to one or more embodiments of the present disclosure converted to a two-wheel mode.

[0039] FIG. 16 is a side view showing the mobile robot of FIG. 15 according to one or more embodiments of the present disclosure.

[0040] FIG. 17 is a front view showing the mobile robot of FIG. 15 according to one or more embodiments of the present disclosure.

[0041] FIG. 18 is a block diagram of a mobile robot according to one or more embodiments of the present disclosure.

[0042] It should be understood that the various embodiments and terms used in this document are not intended to limit the technical features described in this document to specific embodiments, but rather include various modifications, equivalents, or alternatives of the embodiments.

[0043] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0044] The singular form of a noun corresponding to an item may include one or more of said items, unless the relevant context clearly indicates otherwise.

[0045] In this document, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in that phrase, or all possible combinations thereof.

[0046] The term "and / or" includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0047] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not qualify the components in any other respect (e.g., importance or order).

[0048] When a component (e.g., a first component) is referred to as being "coupled" or "connected" to another component (e.g., a second component), with or without the terms "functionally" or "communicatively," it means that the component can be connected to the other component directly (e.g., wired), wirelessly, or through a third component.

[0049] The terms "include" or "have" are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in this document, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0050] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0051] When we say that a component is "on" another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0052] In addition, terms such as 'front end', 'rear end', 'upper end', 'lower end', 'top end', and 'bottom end' used in the present disclosure are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0053] The present disclosure aims to provide a mobile robot having high driving performance both indoors and outdoors.

[0054] Hereinafter, a mobile robot (1) according to one or more embodiments of the present disclosure will be described in detail with reference to FIGS. 1 to 3.

[0055] FIG. 1 is a side view showing a mobile robot (1) according to one or more embodiments of the present disclosure. FIG. 2 is a plan view showing the mobile robot (1) of FIG. 1 according to one or more embodiments of the present disclosure. FIG. 3 is a side view showing the mobile robot (1) of FIG. 1 according to one or more embodiments of the present disclosure in a state converted to a two-wheel mode. For reference, in FIG. 2, the upper support plate (11) of the mobile robot (1) is removed.

[0056] Referring to FIGS. 1 to 3, a mobile robot (1) according to one or more embodiments of the present disclosure may include a body (10), a pair of front driving wheels (20), a pair of rear driving wheels (30), four auxiliary wheels (40), and a wheel variable device (50, 60).

[0057] The body (10) is formed to support and fix a pair of front driving wheels (20), a pair of rear driving wheels (30), four auxiliary wheels (40), and a wheel variable device (50, 60).

[0058] A module (3) corresponding to the purpose of the mobile robot (1) may be installed on the upper surface of the body (10). For example, if the mobile robot (1) is used for delivery, a delivery module may be installed on the upper surface of the body (10). If the mobile robot (1) is used for guidance, a guidance module may be installed on the upper surface of the body (10).

[0059] The body (10) may include an upper support plate (11) and a lower support plate (12).

[0060] The upper support plate (11) and the lower support plate (12) can be spaced apart from each other vertically by a certain distance. A plurality of support posts (13) can be installed between the upper support plate (11) and the lower support plate (12). For example, the upper support plate (11) and the lower support plate (12) are connected by a plurality of support posts (13).

[0061] The upper support plate (11) may be formed as a flat plate having a roughly rectangular shape. The lower support plate (12) may be formed in a shape corresponding to the upper support plate (11). The lower support plate (12) may be formed as a flat plate having a roughly rectangular shape.

[0062] A pair of front drive wheels (20) may be installed at the front of the body (10). Each of the pair of front drive wheels (20) may include a front in-wheel motor (21). The front in-wheel motor (21) may be installed at the center of the front drive wheel (20). The front drive wheel (20) may be rotated by the front in-wheel motor (21).

[0063] A pair of front drive wheels (20) can be installed on the body (10) to selectively contact the running surface (100). When the mobile robot (1) is in two-wheel mode, the pair of front drive wheels (20) do not contact the running surface (100). When the mobile robot (1) is in four-wheel mode, the pair of front drive wheels (20) contact the running surface (100). Here, the running surface (100) refers to a surface on which the mobile robot (1) can move, such as a road, sidewalk, floor of a building, hallway, or floor of an elevator.

[0064] When a pair of front drive wheels (20) contact the driving surface (100), the pair of front drive wheels (20) may protrude below the lower surface of the body (10).

[0065] When a pair of front driving wheels (20) contact the running surface (100), the pair of front driving wheels (20) may protrude lower than the four auxiliary wheels (40) installed on the lower surface of the body (10). Therefore, when a pair of front driving wheels (20) contact the running surface (100), the four auxiliary wheels (40) do not contact the running surface (100).

[0066] A pair of rear drive wheels (30) may be installed at the rear of the body (10). Each of the pair of rear drive wheels (30) may include a rear in-wheel motor (31). The rear in-wheel motor (31) may be installed at the center of the rear drive wheel (30). The rear drive wheel (30) may be rotated by the rear in-wheel motor (31).

[0067] A pair of rear drive wheels (30) can be installed on the body (10) so as to contact the driving surface (100). When the mobile robot (1) is in two-wheel mode and four-wheel mode, a pair of rear drive wheels (30) contact the driving surface (100).

[0068] A pair of rear drive wheels (30) can be installed so as to protrude lower than the lower surface of the body (10).

[0069] In the case of a four-wheel mode in which a pair of front drive wheels (20) contact the running surface (100), a pair of rear drive wheels (30) may protrude lower than the four auxiliary wheels (40) installed on the lower surface of the body (10). Therefore, when a pair of front drive wheels (20) contact the running surface (100), the four auxiliary wheels (40) do not contact the running surface (100).

[0070] In the two-wheel mode where a pair of front drive wheels (20) do not contact the running surface (100), a pair of rear drive wheels (30) may protrude at the same height as four auxiliary wheels (40) installed on the lower surface of the body (10). Therefore, when a pair of front drive wheels (20) do not contact the running surface (100), the four auxiliary wheels (40) contact the running surface (100) together with a pair of rear drive wheels (30).

[0071] Four auxiliary wheels (40) can be installed on the lower surface of the body (10). The four auxiliary wheels (40) can be wheels that can rotate in all directions. For example, casters, omni wheels, mecanum wheels, etc. can be used as the auxiliary wheels (40).

[0072] The wheel variable device (50, 60) is formed so that the mobile robot (1) can be changed into one of the four-wheel mode and the two-wheel mode. The wheel variable device (50, 60) is formed so that the positions of a pair of front driving wheels (20) and a pair of rear driving wheels (30) of the mobile robot (1) can be changed into one of the four-wheel mode and the two-wheel mode.

[0073] In 4-wheel mode, a pair of front drive wheels (20) and a pair of rear drive wheels (30) are in contact with the driving surface (100). In 4-wheel mode, the four auxiliary wheels (40) are spaced from the driving surface (100).

[0074] In two-wheel mode, a pair of front drive wheels (20) are spaced from the driving surface (100) and a pair of rear drive wheels (30) are in contact with the driving surface (100). In two-wheel mode, four auxiliary wheels (40) are in contact with the driving surface (100).

[0075] The wheel variable device may include a front wheel variable device (50) and a rear wheel variable device (60).

[0076] The front wheel variable device (50) is formed to be able to move a pair of front drive wheels (20). The front wheel variable device (50) is formed to be able to move a pair of front drive wheels (20) up and down with respect to the body (10). In the four-wheel mode, the front wheel variable device (50) lowers a pair of front drive wheels (20) so that the pair of front drive wheels (20) come into contact with the driving surface (100). In the two-wheel mode, the front wheel variable device (50) raises a pair of front drive wheels (20) so that the pair of front drive wheels (20) are separated from the driving surface (100).

[0077] The front wheel variable device (50) may include a front linear actuator (51). The front linear actuator (51) may be configured to elevate a pair of front drive wheels (20). The pair of front drive wheels (20) may be raised or lowered relative to the lower surface of the body (10) by the front linear actuator (51).

[0078] The front linear actuator (51) can be installed on the upper part of the body (10). For example, the front linear actuator (51) can be installed on the lower surface of the upper support plate (11) of the body (10).

[0079] The front linear actuator (51) may include a front motor (52), a front screw (53), and a front nut (54).

[0080] The front motor (52) is formed to be able to rotate the front screw (53). The front motor (52) is formed to be able to rotate the front screw (53) in both directions. The front motor (52) may include a motor shaft (521).

[0081] The front screw (53) is installed to rotate by the front motor (52). The front screw (53) can be supported at both ends on the lower surface of the upper support plate (11) of the body (10). The front screw (53) can be supported by a pair of support blocks (531) installed on the lower surface of the upper support plate (11).

[0082] One end of the front screw (53) can be coupled to the motor shaft (521) of the front motor (52) by a coupling (522). Therefore, when the motor shaft (521) rotates, the front screw (53) rotates integrally with the motor shaft (521).

[0083] The front nut (54) is screw-connected to the front screw (53). Therefore, when the front screw (53) rotates, the front nut (54) can move linearly along the front screw (53). For example, the front screw (53) and the front nut (54) convert the rotation of the front motor (52) into linear movement of the front nut (54). The front screw (53) and the front nut (54) may include a lead screw and nut or a ball screw and a ball nut.

[0084] The front wheel variable device (50) may include an upper arm (56) and a lower arm (57).

[0085] The upper arm (56) connects the front linear actuator (51) and the front driving wheel (20). One end of the upper arm (56) is connected to the front linear actuator (51), and the other end is connected to the front driving wheel (20). One end of the upper arm (56) is rotatably connected to the front nut (54) of the front linear actuator (51), and the other end of the upper arm (56) is rotatably connected to the front driving wheel (20).

[0086] The lower arm (57) connects the body (10) and the front drive wheel (20). One end of the lower arm (57) is connected to the lower part of the body (10), i.e., the lower support plate (12) of the body (10), and the other end is connected to the front drive wheel (20). One end of the lower arm (57) is rotatably connected to the lower part of the body (10), and the other end of the lower arm (57) is rotatably connected to the front drive wheel (20).

[0087] When the front drive wheel (20) includes a front in-wheel motor (21), the other end of the upper arm (56) and the other end of the lower arm (57) can be rotatably connected to a support bracket that supports the front in-wheel motor (21).

[0088] The front wheel variable device (50) may include a pair of upper arms (56) and a pair of lower arms (57) corresponding to a pair of front driving wheels (20). For example, the front wheel variable device (50) may include a left upper arm (56) and a left lower arm (57) connected to the left front driving wheel (20), and a right upper arm (56) and a right lower arm (57) connected to the right front driving wheel (20).

[0089] A pair of upper arms (56) and a pair of lower arms (57) can be formed so that a pair of front driving wheels (20) protrude to the maximum extent toward the front of the body (10). If a pair of front driving wheels (20) are formed so that a pair of front driving wheels (20) protrude to the maximum extent toward the front of the body (10), the area of ​​the support polygon of the mobile robot (1) can be increased.

[0090] Therefore, when the front motor (52) rotates, one end of the upper arm (56) can move linearly along the front screw (53). For example, when the front motor (52) rotates, the front screw (53) rotates. When the front screw (53) rotates, the front nut (54) screw-connected to the front screw (53) moves linearly along the front screw (53). Since one end of the upper arm (56) is rotatably connected to the front nut (54), when the front screw (53) rotates, one end of the upper arm (56) moves linearly along the front screw (53).

[0091] When the upper arm (56) moves in a straight line along the front screw (53), the front drive wheel (20) is rotated at a certain angle with respect to the body (10) by the upper arm (56) and the lower arm (57). When the front motor (52) rotates in one direction, the front drive wheel (20) rotates upward with respect to the body (10) in a counterclockwise direction and rises. When the front motor (52) rotates in the opposite direction, the front drive wheel (20) rotates downward with respect to the body (10) in a clockwise direction and descends.

[0092] The rear wheel variable device (60) is formed so as to be able to move a pair of rear drive wheels (30). The rear wheel variable device (60) is formed so as to be able to move a pair of rear drive wheels (30) forward and backward with respect to the body (10).

[0093] In the four-wheel mode, the rear wheel variable device (60) moves a pair of rear drive wheels (30) to the rear of the body (10) so that the pair of rear drive wheels (30) protrude from the rear end of the body (10). The pair of rear drive wheels (30) can be installed so as to protrude as much as possible to the rear of the body (10). By making the pair of rear drive wheels (30) protrude as much as possible from the rear end of the body (10), the area of ​​the support polygon of the mobile robot (1) can be increased.

[0094] In two-wheel mode, the rear wheel variable device (60) moves a pair of rear drive wheels (30) to the center of the body (10) so that the pair of rear drive wheels (30) are positioned at the center of the body (10), and the body (10) is lowered. Then, four auxiliary wheels (40) installed on the lower surface of the body (10) come into contact with the driving surface (100). At this time, one pair of rear drive wheels (30) is positioned at the center of the four auxiliary wheels (40). For example, as illustrated in FIG. 3, two auxiliary wheels (40) are positioned on the left side of one pair of rear drive wheels (30), and the other two auxiliary wheels (40) are positioned on the right side of one pair of rear drive wheels (30).

[0095] The rear wheel variable device (60) may include a rear linear actuator (61). The rear linear actuator (61) may be configured to move a pair of rear drive wheels (30) forward and backward with respect to the body (10). The pair of rear drive wheels (30) may be positioned at the rear of the body (10) or at the center of the body (10) by the rear linear actuator (61).

[0096] The rear linear actuator (61) can be installed at the lower part of the body (10). For example, the rear linear actuator (61) can be installed at the upper surface of the lower support plate (12) of the body (10).

[0097] The body (10) may include an inclined block (15) installed on the upper surface of the lower support plate (12). The rear linear actuator (61) may be installed on the inclined surface (151) of the inclined block (15).

[0098] The inclined block (15) can be formed to have an upwardly inclined inclined surface (151) with respect to the lower support plate (12). The inclined block (15) can be installed so that the high point of the inclined surface (151) is adjacent to the front end of the body (10) and the low point of the inclined surface (151) is adjacent to the rear end of the body (10). The angle of the inclined surface (151) can be determined so that when a pair of rear driving wheels (30) are positioned at the center of the body (10), four auxiliary wheels (40) installed on the lower surface of the body (10) come into contact with the driving surface (100).

[0099] The rear linear actuator (61) may include a rear motor (62), a rear screw (63), and a rear nut (64).

[0100] The rear motor (62) is formed to be able to rotate the rear screw (63). The rear motor (62) is formed to be able to rotate the rear screw (63) in both directions. The rear motor (62) may include a motor shaft (621).

[0101] The rear screw (63) is installed to rotate by the rear motor (62). The rear screw (63) can be installed so that both ends are supported on the inclined surface (151) of the inclined block (15) of the lower support plate (12). The rear screw (63) can be supported by a pair of support blocks (631) installed on the inclined surface (151) of the inclined block (15).

[0102] One end of the rear screw (63) can be coupled to the motor shaft (621) of the rear motor (62) by a coupling (622). Therefore, when the motor shaft (621) rotates, the rear screw (63) rotates integrally with the motor shaft (621).

[0103] The rear nut (64) is screw-connected to the rear screw (63). Therefore, when the rear screw (63) rotates, the rear nut (64) can move linearly along the rear screw (63). For example, the rear screw (63) and the rear nut (64) are formed to convert the rotational motion of the rear motor (62) into the linear motion of the rear nut (64). The rear screw (63) and the rear nut (64) may include a lead screw and a nut or a ball screw and a ball nut.

[0104] The rear wheel variable device (60) may include a support bar (66) connecting a pair of rear drive wheels (30) and a rear linear actuator (61). One end of the support bar (66) may be connected to the rear linear actuator (61), and the other end may be connected to a pair of rear drive wheels (30).

[0105] The support bar (66) can be coupled to the rear nut (64) of the rear linear actuator (61). For example, the rear nut (64) can be installed at the center of the support bar (66). Therefore, when the rear nut (64) moves linearly by the rear screw (63), the support bar (66) can also move linearly along the rear screw (63) as one unit with the rear nut (64).

[0106] A pair of rear drive wheels (30) may be installed at both ends of the support bar (66). If the pair of rear drive wheels (30) include a rear in-wheel motor (31), both ends of the support bar (66) may be connected to a support bracket that supports the rear in-wheel motor (31).

[0107] Therefore, when the rear motor (62) rotates, the support bar (66) can move linearly along the rear screw (63). For example, when the rear motor (62) rotates, the rear screw (63) rotates. When the rear screw (63) rotates, the rear nut (64) screw-coupled to the rear screw (63) moves linearly along the rear screw (63). Since the support bar (66) is coupled to the rear nut (64), when the rear screw (63) rotates, the support bar (66) moves linearly along the rear screw (63).

[0108] When the support bar (66) moves in a straight line along the rear screw (63) installed on the inclined block (15), the body (10) is raised or lowered with respect to the driving surface (100) by the inclined block (15). When the rear motor (62) rotates in one direction, the rear drive wheel (30) moves to the center of the body (10) and the body (10) is lowered. When the rear motor (62) rotates in the opposite direction, the rear drive wheel (30) moves rearward and the body (10) is raised.

[0109] In the four-wheel mode illustrated in FIGS. 1 and 2, a pair of front drive wheels (20) and a pair of rear drive wheels (30) contact the driving surface (100). At this time, a pair of front drive wheels (20) protrude to the maximum from the front end of the body (10), and a pair of rear drive wheels (30) protrude to the maximum from the rear end of the body (10). Therefore, since the area of ​​the support polygon of the mobile robot (1) can be increased, the mobile robot (1) can stably move on an uneven driving surface (100), such as outdoors.

[0110] In the two-wheel mode illustrated in FIG. 3, a pair of front drive wheels (20) are spaced apart from the running surface (100), and a pair of rear drive wheels (30) and four auxiliary wheels (40) come into contact with the running surface (100). At this time, a pair of front drive wheels (20) are raised and positioned inside the body (10), and a pair of rear drive wheels (30) are positioned at the center of the body (10). Therefore, the area of ​​the support polygon of the mobile robot (1) can be minimized, so that the mobile robot (1) can move efficiently in a narrow space such as indoors. In particular, in the two-wheel mode, the mobile robot (1) can rotate in place by a pair of rear drive wheels (30).

[0111] FIG. 4 is a perspective view showing a mobile robot (1) according to one or more embodiments of the present disclosure. FIG. 5 is a side view showing the mobile robot (1) of FIG. 4 according to one or more embodiments of the present disclosure. FIG. 6 is a front view showing the mobile robot (1) of FIG. 4 according to one or more embodiments of the present disclosure. FIG. 7 is a rear view showing the mobile robot (1) of FIG. 4 according to one or more embodiments of the present disclosure. FIG. 8 is a plan view showing the mobile robot (1) of FIG. 4 according to one or more embodiments of the present disclosure with the upper support plate (11) removed. FIG. 9 is a perspective view showing a front linear actuator (51) of the mobile robot (1) according to one or more embodiments of the present disclosure. FIG. 10 is a perspective view showing a rear linear actuator (61) of the mobile robot (1) according to one or more embodiments of the present disclosure.

[0112] Referring to FIGS. 4 to 8, the mobile robot (1) may include a body (10), a pair of front driving wheels (20), a pair of rear driving wheels (30), four auxiliary wheels (40), and a wheel variable device (50, 60).

[0113] The body (10) is formed to support and fix a pair of front driving wheels (20), a pair of rear driving wheels (30), four auxiliary wheels (40), and a wheel variable device (50, 60).

[0114] A module (3) corresponding to the purpose of the mobile robot (1) may be installed on the upper surface of the body (10) (see Fig. 1). For example, a delivery module, a guidance module, etc. may be installed on the upper surface of the body (10).

[0115] The body (10) may include an upper support plate (11) and a lower support plate (12).

[0116] The upper support plate (11) and the lower support plate (12) may be spaced apart from each other by a certain distance in the vertical direction. A plurality of support posts (13) may be installed between the upper support plate (11) and the lower support plate (12). The upper support plate (11) and the lower support plate (12) are connected by the plurality of support posts (13). For example, six support posts (13) may be installed between the upper support plate (11) and the lower support plate (12).

[0117] The upper support plate (11) may be formed as a flat plate having a roughly rectangular shape. The lower support plate (12) may be formed in a shape corresponding to the upper support plate (11). The lower support plate (12) may be formed as a flat plate having a roughly rectangular shape. The lower support plate (12) may be formed to be smaller than the upper support plate (11).

[0118] A pair of front drive wheels (20) may be installed at the front of the body (10). The pair of front drive wheels (20) may be installed so as to protrude forward from the front of the body (10). Each of the pair of front drive wheels (20) may include a front in-wheel motor (21). The front in-wheel motor (21) may be installed at the center of the front drive wheel (20). The front drive wheel (20) may be rotated by the front in-wheel motor (21).

[0119] A pair of front drive wheels (20) can be installed on the body (10) to selectively contact the running surface (100). When the mobile robot (1) is in two-wheel mode, the pair of front drive wheels (20) do not contact the running surface (100). When the mobile robot (1) is in four-wheel mode, the pair of front drive wheels (20) contact the running surface (100). Here, the running surface (100) refers to a surface on which the mobile robot (1) can move, such as a road, sidewalk, floor of a building, hallway, or floor of an elevator.

[0120] When a pair of front drive wheels (20) contact the driving surface (100), the pair of front drive wheels (20) may protrude lower than the lower surface of the body (10) and may protrude forward than the front surface of the body (10).

[0121] When a pair of front driving wheels (20) contact the running surface (100), the pair of front driving wheels (20) may protrude lower than the four auxiliary wheels (40) installed on the lower surface of the body (10). Therefore, when a pair of front driving wheels (20) contact the running surface (100), the four auxiliary wheels (40) do not contact the running surface (100).

[0122] When the mobile robot (1) is in two-wheel mode, a pair of front driving wheels (20) may be located inside the body (10) and may not protrude forward of the body (10).

[0123] A pair of rear drive wheels (30) may be installed at the rear of the body (10). Each of the pair of rear drive wheels (30) may include a rear in-wheel motor (31). The rear in-wheel motor (31) may be installed at the center of the rear drive wheel (30). The rear drive wheel (30) may be rotated by the rear in-wheel motor (31).

[0124] A pair of rear drive wheels (30) can be installed on the body (10) so as to be in contact with the running surface (100). When the mobile robot (1) is running, regardless of whether it is in two-wheel mode or four-wheel mode, the pair of rear drive wheels (30) always come into contact with the running surface (100).

[0125] A pair of rear drive wheels (30) can be installed so as to protrude lower than the lower surface of the body (10) and protrude rearward than the rear surface of the body (10).

[0126] In the case of a four-wheel mode in which a pair of front drive wheels (20) contact the running surface (100), a pair of rear drive wheels (30) may protrude lower than the four auxiliary wheels (40) installed on the lower surface of the body (10). Therefore, when a pair of front drive wheels (20) contact the running surface (100), the four auxiliary wheels (40) do not contact the running surface (100).

[0127] In the two-wheel mode where a pair of front drive wheels (20) do not contact the running surface (100), a pair of rear drive wheels (30) may protrude at the same height as four auxiliary wheels (40) installed on the lower surface of the body (10). Therefore, when a pair of front drive wheels (20) do not contact the running surface (100), the four auxiliary wheels (40) contact the running surface (100) together with a pair of rear drive wheels (30).

[0128] The wheel variable device (50, 60) is formed so that the mobile robot (1) can be changed into one of the four-wheel mode and the two-wheel mode. The wheel variable device (50, 60) is formed so that the positions of a pair of front driving wheels (20) and a pair of rear driving wheels (30) of the mobile robot (1) can be changed into one of the four-wheel mode and the two-wheel mode.

[0129] The 4-wheel mode is a state in which a pair of front drive wheels (20) and a pair of rear drive wheels (30) are in contact with the driving surface (100). The pair of front drive wheels (20) protrude forward from the front of the body (10), and the pair of rear drive wheels (30) protrude backward from the rear of the body (10). In the 4-wheel mode, the four auxiliary wheels (40) are spaced from the driving surface (100).

[0130] In the two-wheel mode, a pair of front drive wheels (20) are spaced from the running surface (100) and a pair of rear drive wheels (30) are in contact with the running surface (100). The pair of front drive wheels (20) are located inside the body (10) and do not protrude from the front of the body (10). The pair of rear drive wheels (30) are located at the center of the body (10). In the two-wheel mode, four auxiliary wheels (40) are in contact with the running surface (100). In the two-wheel mode, when the pair of rear drive wheels (30) move to the center of the body (10), the body (10) is lowered and the four auxiliary wheels (40) are in contact with the running surface (100).

[0131] The wheel variable device may include a front wheel variable device (50) and a rear wheel variable device (60).

[0132] The front wheel variable device (50) is formed so as to be able to move a pair of front driving wheels (20). The front wheel variable device (50) is formed so as to be able to move a pair of front driving wheels (20) up and down with respect to the body (10).

[0133] In four-wheel mode, the front wheel variable device (50) lowers a pair of front drive wheels (20) so that the pair of front drive wheels (20) come into contact with the driving surface (100). The front wheel variable device (50) lowers a pair of front drive wheels (20) so that the pair of front drive wheels (20) protrude toward the front and bottom of the body (10).

[0134] In two-wheel mode, the front wheel variable device (50) raises the pair of front drive wheels (20) so that the pair of front drive wheels (20) are spaced from the driving surface (100). The front wheel variable device (50) raises the pair of front drive wheels (20) so that the pair of front drive wheels (20) are positioned inside the body (10), i.e., in the space between the upper support plate (11) and the lower support plate (12). At this time, the pair of front drive wheels (20) may not protrude from the front of the body (10), i.e., from the front ends of the upper support plate (11) and the lower support plate (12).

[0135] The front wheel variable device (50) may include a front linear actuator (51). The front linear actuator (51) may be configured to elevate a pair of front drive wheels (20). The pair of front drive wheels (20) may be positioned above or protrude downward from the lower surface of the body (10) by the front linear actuator (51).

[0136] The front linear actuator (51) can be installed on the upper part of the body (10). For example, the front linear actuator (51) can be installed on the lower surface of the upper support plate (11) of the body (10).

[0137] Referring to FIGS. 5, 8, and 9, the front linear actuator (51) may include a front motor (52), a front screw (53), and a front nut (54).

[0138] The front motor (52) may be installed on the lower surface of the upper support plate (11). The front motor (52) is formed to be able to rotate the front screw (53). The front motor (52) is formed to be able to rotate the front screw (53) in both directions. The front motor (52) may include a motor shaft (521).

[0139] The front screw (53) is installed to rotate by the front motor (52). The front screw (53) can be supported at both ends on the lower surface of the upper support plate (11) of the body (10). The front screw (53) can be supported by a pair of support blocks (531) installed on the lower surface of the upper support plate (11).

[0140] One end of the front screw (53) can be coupled to the motor shaft (521) of the front motor (52) by a coupling (522). Therefore, when the motor shaft (521) rotates, the front screw (53) rotates integrally with the motor shaft (521).

[0141] The front nut (54) is screw-connected to the front screw (53). Therefore, when the front screw (53) rotates, the front nut (54) can move linearly along the front screw (53). For example, the front screw (53) and the front nut (54) convert the rotation of the front motor (52) into linear movement of the front nut (54). The front screw (53) and the front nut (54) can be formed by a lead screw and nut or a ball screw and a ball nut.

[0142] The front wheel variable device (50) may include an upper arm (56) and a lower arm (57).

[0143] The upper arm (56) connects the front linear actuator (51) and the front driving wheel (20). One end of the upper arm (56) is connected to the front linear actuator (51), and the other end is connected to the front driving wheel (20). One end of the upper arm (56) is rotatably connected to the front nut (54) of the front linear actuator (51), and the other end of the upper arm (56) is rotatably connected to the front driving wheel (20).

[0144] The upper arm (56) may be formed as a suspension. The suspension is formed to absorb shock applied to the front driving wheel (20). The suspension may include a coil spring and a shock absorber. The coil spring and the shock absorber may be arranged in a straight line.

[0145] The lower arm (57) connects the body (10) and the front drive wheel (20). One end of the lower arm (57) is connected to the lower part of the body (10), i.e., the lower support plate (12) of the body (10), and the other end is connected to the front drive wheel (20). One end of the lower arm (57) is rotatably connected to the lower part of the body (10), and the other end of the lower arm (57) is rotatably connected to the front drive wheel (20).

[0146] When the front driving wheel (20) includes a front in-wheel motor (21), the other end of the upper arm (56) and the other end of the lower arm (57) can be rotatably connected to a support bracket (23) that supports the front in-wheel motor (21).

[0147] The front wheel variable device (50) may include a pair of upper arms (56) and a pair of lower arms (57) corresponding to a pair of front driving wheels (20). For example, the front wheel variable device (50) may include a left upper arm (56) and a left lower arm (57) connected to the left front driving wheel (20), and a right upper arm (56) and a right lower arm (57) connected to the right front driving wheel (20).

[0148] The front wheel variable device (50) may include a middle bar (55) connecting a pair of upper arms (56) and a front nut (54). The front nut (54) is connected to the center of the middle bar (55), one end of a left upper arm (56) may be connected to the left end of the middle bar (55), and a right upper arm (56) may be connected to the right end of the middle bar (55).

[0149] A left hinge (551) that rotatably supports one end of the left upper arm (56) may be provided at the left end of the middle bar (55). The left hinge (551) may be guided by a left LM guide (58). The left LM guide (58) may be installed on the lower surface of the upper support plate (11).

[0150] A right hinge (552) may be provided on the right end of the middle bar (55) to rotatably support one end of the right upper arm (56). The right hinge (552) may be guided by a right LM guide (59). The right LM guide (59) may be installed on the lower surface of the upper support plate (11). The right LM guide (59) may be installed parallel to the left LM guide (58).

[0151] The other end of the left upper arm (56) is rotatably installed on the left support bracket (23) installed on the front in-wheel motor (21) of the left front driving wheel (20).

[0152] The other end of the upper right arm (56) is rotatably installed on the right support bracket (23) installed on the front in-wheel motor (21) of the right front driving wheel (20).

[0153] One end of the lower left arm (57) can be rotatably supported by a lower left hinge (571) installed on the lower support plate (12).

[0154] The other end of the left lower arm (57) is rotatably installed on the left support bracket (23) installed on the front in-wheel motor (21) of the left front driving wheel (20).

[0155] One end of the lower right arm (57) can be rotatably supported by a lower right hinge (571) installed on the lower support plate (12).

[0156] The other end of the lower right arm (57) is rotatably installed on the right support bracket (23) installed on the front in-wheel motor (21) of the right front driving wheel (20).

[0157] The front wheel variable device (50) can be formed with a MacPherson strut suspension.

[0158] A pair of upper arms (56) and a pair of lower arms (57) can be formed so that a pair of front driving wheels (20) protrude as far forward as possible from the body (10). If a pair of front driving wheels (20) are formed so that a pair of front driving wheels (20) protrude as far forward as possible from the body (10), the area of ​​the support polygon of the mobile robot (1) can be increased.

[0159] Therefore, when the front motor (52) rotates, one end of the upper arm (56) can move linearly along the front screw (53). For example, when the front motor (52) rotates, the front screw (53) rotates. When the front screw (53) rotates, the front nut (54) screw-connected to the front screw (53) moves linearly along the front screw (53). Since one end of a pair of upper arms (56) is rotatably connected to the front nut (54) by the middle bar (55), when the front screw (53) rotates, one end of the pair of upper arms (56) moves linearly along the front screw (53).

[0160] When a pair of upper arms (56) move linearly along the front screw (53), a pair of front drive wheels (20) are rotated at a certain angle with respect to the body (10) by a pair of upper arms (56) and a pair of lower arms (57). When the front motor (52) rotates in one direction, a pair of front drive wheels (20) rotate upward with respect to the body (10), i.e., counterclockwise, and rise. When the front motor (52) rotates in the opposite direction, a pair of front drive wheels (20) rotate downward with respect to the body (10), i.e., clockwise, and descend.

[0161] The rear wheel variable device (60) is formed so as to be able to move a pair of rear drive wheels (30). The rear wheel variable device (60) is formed so as to be able to move a pair of rear drive wheels (30) forward and backward with respect to the body (10).

[0162] In the four-wheel mode, the rear wheel variable device (60) moves a pair of rear drive wheels (30) to the rear of the body (10) so that the pair of rear drive wheels (30) protrude from the rear end of the body (10). The pair of rear drive wheels (30) can be installed so as to protrude as much as possible to the rear of the body (10). By making the pair of rear drive wheels (30) protrude as much as possible from the rear end of the body (10), the area of ​​the support polygon of the mobile robot (1) can be increased.

[0163] In two-wheel mode, the rear wheel variable device (60) moves a pair of rear drive wheels (30) to the center of the body (10) to position the pair of rear drive wheels (30) at the center of the body (10) and lower the body (10). Then, four auxiliary wheels (40) installed on the lower surface of the body (10) come into contact with the driving surface (100). At this time, one pair of rear drive wheels (30) is positioned at the center of the four auxiliary wheels (40). For example, as illustrated in FIG. 16, two auxiliary wheels (40) are positioned on the left side of one pair of rear drive wheels (30), and the other two auxiliary wheels (40) are positioned on the right side of one pair of rear drive wheels (30).

[0164] The rear wheel variable device (60) may include a rear linear actuator (61). The rear linear actuator (61) may be configured to move a pair of rear drive wheels (30) forward and backward with respect to the body (10). The pair of rear drive wheels (30) may be positioned at the rear of the body (10) or at the center of the body (10) by the rear linear actuator (61).

[0165] The rear linear actuator (61) can be installed at the lower part of the body (10). For example, the rear linear actuator (61) can be installed at the upper surface of the lower support plate (12) of the body (10).

[0166] The body (10) may include an inclined block (15) installed on the upper surface of the lower support plate (12). The rear linear actuator (61) may be installed on the inclined surface (151) of the inclined block (15).

[0167] The inclined block (15) can be formed to have an upwardly inclined inclined surface (151) with respect to the lower support plate (12). The inclined block (15) can be installed so that the high point of the inclined surface (151) is adjacent to the front end of the body (10) and the low point of the inclined surface (151) is adjacent to the rear end of the body (10). The angle of the inclined surface (151) can be determined so that when a pair of rear driving wheels (30) are positioned at the center of the body (10), four auxiliary wheels (40) installed on the lower surface of the body (10) come into contact with the driving surface (100).

[0168] Referring to FIGS. 5, 8, and 10, the rear linear actuator (61) may include a rear motor (62), a rear screw (63), and a rear nut (64).

[0169] The rear motor (62) can be installed on the lower support plate (12). The rear motor (62) can be installed on one end of the inclined block (15). The rear motor (62) can be installed at the high point of the inclined block (15). The rear motor (62) can be supported by a motor bracket (623) installed on one end of the inclined block (15).

[0170] The rear motor (62) is formed to be able to rotate the rear screw (63). The rear motor (62) is formed to be able to rotate the rear screw (63) in both directions. The rear motor (62) may include a motor shaft (621).

[0171] The rear screw (63) is installed to rotate by the rear motor (62). The rear screw (63) can be installed so that both ends are supported on the inclined surface (151) of the inclined block (15) of the lower support plate (12). The rear screw (63) can be supported by a pair of support blocks (631) installed on the inclined surface (151) of the inclined block (15).

[0172] One end of the rear screw (63) can be coupled to the motor shaft (621) of the rear motor (62) by a coupling (622). Therefore, when the motor shaft (621) rotates, the rear screw (63) rotates integrally with the motor shaft (621).

[0173] The rear nut (64) is screw-connected to the rear screw (63). Therefore, when the rear screw (63) rotates, the rear nut (64) can move linearly along the rear screw (63). For example, the rear screw (63) and the rear nut (64) are formed to convert the rotational motion of the rear motor (62) into the linear motion of the rear nut (64). The rear screw (63) and the rear nut (64) can be formed as a lead screw and nut or a ball screw and a ball nut.

[0174] The linear movement of the rear nut (64) can be guided by an LM guide (65). The LM guide (65) can be installed on the upper surface of the inclined block (15). The LM guide (65) can be installed between a pair of support blocks (631).

[0175] The LM guide (65) may include an LM block (651). The LM block (651) is installed to be able to slide relative to the LM guide (65). A rear nut (64) is installed on the upper surface of the LM block (651). Therefore, the rear nut (64) can slide in a straight line along the LM guide (65).

[0176] The rear wheel variable device (60) may include a support bar (66) connecting a pair of rear drive wheels (30) and a rear linear actuator (61). One end of the support bar (66) may be connected to the rear linear actuator (61), and the other end may be connected to a pair of rear drive wheels (30).

[0177] The support bar (66) can be coupled to the rear nut (64). For example, the rear nut (64) can be installed at the center of the support bar (66). Therefore, when the rear nut (64) moves linearly by the rear screw (63), the support bar (66) can also move linearly along the rear screw (63) as one unit with the rear nut (64).

[0178] The support bar (66) may include a left support bar (661) and a right support bar (662).

[0179] One end of the left support bar (661) is fixed to the rear nut (64), and the other end is connected to the support bracket (33) that supports the rear in-wheel motor (31) of the left rear drive wheel (30).

[0180] One end of the right support bar (662) is fixed to the rear nut (64), and the other end is connected to the support bracket (33) that supports the rear in-wheel motor (31) of the right rear drive wheel (30). The right support bar (662) can be installed symmetrically with respect to the left support bar (661) with the rear nut (64) as the center.

[0181] Since the left support bar (661) and the right support bar (662) are formed with the same structure, the left support bar (661) will be described in detail below with reference to FIGS. 10, 11a, 11b, and 11c.

[0182] FIG. 11a is a partial diagram showing a left support bar (661) of a rear wheel variable device (60) of a mobile robot (1) according to one or more embodiments of the present disclosure. FIG. 11b is a partial diagram showing a left support bar (661) of a rear wheel variable device (60) when a rear driving wheel (30) of a mobile robot (1) according to one or more embodiments of the present disclosure is raised. FIG. 11c is a partial diagram showing a left support bar (661) of a rear wheel variable device (60) when a rear driving wheel (30) of a mobile robot (1) according to one or more embodiments of the present disclosure is lowered.

[0183] Referring to FIGS. 10, 11a, 11b, and 11c, the left support bar (661) may include a fixed plate (663), a movable plate (664), an upper link (665), a lower link (666), and a coil spring (667).

[0184] The fixed plate (663) can be installed on the rear linear actuator (61). For example, the fixed plate (663) can be fixed to the rear nut (64) of the rear linear actuator (61). The fixed plate (663) can be formed as a rectangular flat plate.

[0185] The moving plate (664) may be spaced apart from the fixed plate (663) by a certain distance and may be installed parallel to the fixed plate (663). The moving plate (664) may be formed as a rectangular flat plate. A rear driving wheel (30) may be installed on the moving plate (664). The rear driving wheel (30) may be installed at the bottom of the moving plate (664). The moving plate (664) may be installed on the support bracket (33) of the rear in-wheel motor (31) of the rear driving wheel (30).

[0186] The upper link (665) and the lower link (666) can be installed between the fixed plate (663) and the movable plate (664).

[0187] One end of the upper link (665) may be rotatably installed on a fixed plate (663), and the other end may be rotatably installed on a movable plate (664). The upper link (665) may be formed in the shape of a straight bar.

[0188] The lower link (666) may be installed below the upper link (665). One end of the lower link (666) may be rotatably installed on a fixed plate (663), and the other end may be rotatably installed on a movable plate (664). The lower link (666) may be formed in the shape of a curved bar protruding upward. If the lower link (666) is formed in the shape of a curved bar, interference with the lower support plate (12) can be prevented.

[0189] Accordingly, the rear drive wheel (30) can move vertically with respect to the rear linear actuator (61) by the upper link (665), the lower link (666), and the moving plate (664).

[0190] The coil spring (667) may be formed to apply a force in a downward direction to the rear drive wheel (30). When the coil spring (667) applies a force in a downward direction to the rear drive wheel (30), the rear drive wheel (30) can maintain contact with the driving surface (100). Therefore, when the driving surface (100) is uneven, the rear drive wheel (30) can move while maintaining contact with the driving surface (100).

[0191] The coil spring (667) may be diagonally arranged between the fixed plate (663) and the movable plate (664). The coil spring (667) may be diagonally arranged between the upper link (665) and the lower link (666). For example, one end of the coil spring (667) may be connected to one end of the upper link (665) installed on the movable plate (664), and the other end of the coil spring (667) may be connected to the other end of the lower link (666) installed on the fixed plate (663). At this time, the coil spring (667) may use a tension spring.

[0192] As another example, the coil spring (667) may further include a shock absorber. The coil spring (667) and the shock absorber may be arranged in a straight line.

[0193] Figure 11a illustrates a case where the rear drive wheel (30) moves on a flat surface. At this time, one end and the other end of the lower link (666) are positioned on a horizontal plane (H). One end and the other end of the upper link (665) are positioned on a plane parallel to the horizontal plane (H).

[0194] When the rear drive wheel (30) is located on a convex surface, the rear drive wheel (30) rises as shown in Fig. 11b.

[0195] As shown in Fig. 11b, when the rear drive wheel (30) rises, the other end of the lower link (666) rises a certain height (H1) higher than one end. The other end of the upper link (665) also rises a certain height (H1) higher than one end. Fig. 11b shows a state in which the rear drive wheel (30) rises about 10 mm. At this time, since a tension coil spring (667) is installed between the other end of the upper link (665) and one end of the lower link (666), the rear drive wheel (30) receives a downward force by the coil spring (667). Therefore, the rear drive wheel (30) can maintain contact with the convex surface.

[0196] When the rear drive wheel (30) is located on a concave surface, the rear drive wheel (30) descends as shown in Fig. 11c.

[0197] As shown in Fig. 11c, when the rear drive wheel (30) is lowered, the other end of the lower link (666) is lowered to a certain height (H2) lower than one end. The other end of the upper link (665) is also lowered to a certain height (H2) lower than one end. Fig. 11c shows a state in which the rear drive wheel (30) is lowered to about 20 mm. At this time, since a tension coil spring (667) is installed between the other end of the upper link (665) and one end of the lower link (666), the rear drive wheel (30) is forced downward by the coil spring (667). Therefore, the rear drive wheel (30) can maintain contact with the concave surface.

[0198] In the above, one end of the coil spring (667) is connected to the other end of the upper link (665) installed on the moving plate (664), and the other end of the coil spring (667) is connected to one end of the lower link (666) installed on the fixed plate (663). However, the arrangement of the coil spring (667) is not limited thereto.

[0199] As another example, the coil spring (667) may be arranged in reverse as shown in FIG. 12.

[0200] FIG. 12 is a partial diagram showing a left support bar (661) of a rear wheel variable device (60) of a mobile robot (1) according to one or more embodiments of the present disclosure.

[0201] Referring to Fig. 12, the coil spring (667) may be diagonally arranged between the fixed plate (663) and the movable plate (664). The coil spring (667) may be diagonally arranged between the upper link (665) and the lower link (666). For example, one end of the coil spring (667) may be connected to the other end of the lower link (666) installed on the movable plate (664), and the other end of the coil spring (667) may be connected to one end of the upper link (665) installed on the fixed plate (663). At this time, the coil spring (667) may use a compression spring.

[0202] Then, the coil spring (667) can apply a force in a downward direction to the rear driving wheel (30). When the coil spring (667) applies a force in a downward direction to the rear driving wheel (30), the rear driving wheel (30) can maintain contact with the driving surface (100).

[0203] The left support bar (661) and the right support bar (662) can be formed as a double wishbone suspension.

[0204] When the rear motor (62) rotates, the support bar (66) can move linearly along the rear screw (63). For example, when the rear motor (62) rotates, the rear screw (63) rotates. When the rear screw (63) rotates, the rear nut (64) screw-coupled to the rear screw (63) moves linearly along the rear screw (63). Since the support bar (66) is coupled to the rear nut (64), when the rear screw (63) rotates, the support bar (66) moves linearly along the rear screw (63).

[0205] When the support bar (66) moves in a straight line along the rear screw (63) installed on the inclined block (15), the body (10) is raised or lowered with respect to the driving surface (100) by the inclined block (15). When the rear motor (62) rotates in one direction, the rear drive wheel (30) moves to the center of the body (10) and the body (10) is lowered. When the rear motor (62) rotates in the opposite direction, the rear drive wheel (30) moves rearward and the body (10) is raised.

[0206] In the four-wheel mode illustrated in FIGS. 4 to 8, a pair of front drive wheels (20) and a pair of rear drive wheels (30) contact the driving surface (100). At this time, a pair of front drive wheels (20) protrude to the maximum from the front end of the body (10), and a pair of rear drive wheels (30) protrude to the maximum from the rear end of the body (10). Therefore, since the area of ​​the support polygon of the mobile robot (1) can be increased, the mobile robot (1) can stably move on an uneven driving surface (100), such as outdoors.

[0207] In four-wheel mode, the four auxiliary wheels (40) do not contact the driving surface (100). For example, the four auxiliary wheels (40) are spaced a certain distance from the driving surface (100).

[0208] Four auxiliary wheels (40) may be installed on the lower surface of the body (10). For example, four auxiliary wheels (40) may be installed on the lower surface of the lower support plate (12). Two auxiliary wheels (40) may be installed adjacent to the front end of the lower support plate (12). The other two auxiliary wheels (40) may be installed adjacent to the rear end of the lower support plate (12).

[0209] The auxiliary wheels (40) are formed to enable omnidirectional movement so that the mobile robot (1) can rotate in place in two-wheel mode. In other words, any wheel capable of omnidirectional rotation can be used as the auxiliary wheels (40). For example, casters, omni wheels, mecanum wheels, etc. can be used as the auxiliary wheels (40).

[0210] In the present embodiment, an omni wheel is used as an auxiliary wheel (40) as shown in FIGS. 13 and 14.

[0211] Fig. 13 is a perspective view showing an auxiliary wheel (40) of a mobile robot (1) according to one or more embodiments of the present disclosure. Fig. 14 is a side view of the auxiliary wheel (40) of Fig. 13.

[0212] Referring to FIGS. 13 and 14, the auxiliary wheel (40) may include an auxiliary arm (41) and an elastic member (42).

[0213] The auxiliary arm (41) may be formed in a roughly L shape. An auxiliary wheel (40) may be rotatably installed at one end of the auxiliary arm (41). An elastic member (42) may be installed at the other end of the auxiliary arm (41).

[0214] For example, the auxiliary arm (41) may be formed by a pair of auxiliary arms (41) arranged in parallel. An auxiliary wheel (41) may be rotatably installed between one end of the pair of auxiliary arms (41). The pair of auxiliary arms (41) may be elastically supported by an elastic member (42) installed at the other end.

[0215] The auxiliary arm (41) can be rotatably installed on the lower surface of the lower support plate (12). The auxiliary arm (41) can be rotatably supported by an auxiliary shaft (43). The auxiliary shaft (43) can be supported at both ends by a pair of auxiliary brackets (44). The pair of auxiliary brackets (44) can be installed on the lower surface of the lower support plate (12). Therefore, the auxiliary arm (41) can be rotatably installed on the lower support plate (12) by the auxiliary shaft (43) and the pair of auxiliary brackets (44).

[0216] The elastic member (42) may be installed between the other end of the auxiliary arm (41) and the fixed bracket (45). For example, one end of the elastic member (42) may be supported by the other end of the auxiliary arm (41), and the other end may be supported by the fixed bracket (45). Accordingly, the auxiliary wheel (40) may be elastically supported with respect to the lower support plate (12) by the elastic member (42). A coil spring may be used as the elastic member (42).

[0217] A mobile robot (1) according to one or more embodiments of the present disclosure can be converted from a four-wheel mode to a two-wheel mode by a wheel change device (50, 60). A mobile robot (1) converted to a two-wheel mode is illustrated in FIGS. 15 to 17.

[0218] FIG. 15 is a perspective view illustrating a mobile robot (1) according to one or more embodiments of the present disclosure, which has been converted to a two-wheel mode. FIG. 16 is a side view illustrating the mobile robot (1) of FIG. 15 according to one or more embodiments of the present disclosure. FIG. 17 is a front view illustrating the mobile robot (1) of FIG. 15 according to one or more embodiments of the present disclosure.

[0219] As illustrated in FIGS. 15 to 17, when a mobile robot (1) according to one or more embodiments of the present disclosure is in two-wheel mode, a pair of front drive wheels (20) are spaced apart from a driving surface (100), and a pair of rear drive wheels (30) and four auxiliary wheels (40) are in contact with the driving surface (100). At this time, a pair of front drive wheels (20) are raised and positioned inside the body (10), and a pair of rear drive wheels (30) are positioned at the center of the body (10).

[0220] For example, when the front motor (52) rotates, the front screw (53) rotates. When the front screw (53) rotates, the front nut (54) moves linearly along the front screw (53) toward the center of the body (10). Since a middle bar (55) to which a pair of upper arms (56) are connected is fixed to the front nut (54), the pair of upper arms (56) move linearly along the front screw (53) toward the center of the body (10).

[0221] When a pair of upper arms (56) move in a straight line toward the center of the body (10) along the front screw (53), a pair of front drive wheels (20) are rotated counterclockwise by a certain angle with respect to the body (10) by a pair of upper arms (56) and a pair of lower arms (57). Then, as illustrated in Fig. 16, the pair of front drive wheels (20) are spaced apart from the running surface (100) and are positioned between the upper support plate (11) and the lower support plate (12) of the body (10), and do not protrude from the front of the body (10).

[0222] In addition, when the rear motor (62) rotates, the rear screw (63) rotates, and the rear nut (64) moves along the rear screw (63) to the center of the body (10). At this time, the movement of the rear nut (64) can be guided by the LM guide (65) and the LM block (651). Since a support bar (66) supporting a pair of rear driving wheels (30) is fixed to the rear nut (64), the pair of rear driving wheels (30) move to the center of the body (10).

[0223] Since the LM guide (65) is installed on the inclined surface (151) of the inclined block (15) installed on the lower support plate (12) of the body (10), the rear nut (64) can move along the inclined surface (151), i.e., in a diagonal direction, toward the center of the body (10). Since the rear nut (64) is provided with a support bar (66) that supports a pair of rear drive wheels (30), the pair of rear drive wheels (30) can move along the inclined surface (151), i.e., in a diagonal direction.

[0224] When a pair of rear drive wheels (30) move toward the center of the body (10) along the inclined surface (151) of the inclined block (15) of the body (10), the pair of rear drive wheels (30) remain in contact with the running surface (100) and the body (10) moves downward. When the pair of rear drive wheels (30) are positioned at the center of the body (10), the four auxiliary wheels (40) installed on the lower surface of the body (10) descend and come into contact with the running surface (100). For example, in the two-wheel mode, a pair of rear drive wheels (30) and four auxiliary wheels (40) come into contact with the running surface (100). At this time, two auxiliary wheels (40) are positioned in front of one pair of rear drive wheels (30), and two auxiliary wheels (40) are positioned in the rear of one pair of rear drive wheels (30).

[0225] When the mobile robot (1) is in two-wheel mode, the area of ​​the support polygon of the mobile robot (1) can be minimized, so that the mobile robot (1) can move efficiently in narrow or complex places such as indoors. In particular, in two-wheel mode, the mobile robot (1) can rotate in place by a pair of rear drive wheels (30).

[0226] FIG. 18 is a block diagram of a mobile robot (1) according to one or more embodiments of the present disclosure.

[0227] Referring to FIG. 18, a mobile robot (1) according to one or more embodiments of the present disclosure may include a processor (90).

[0228] The processor (90) may be configured to control the mobile robot (1) in whole or in part. For example, the processor (90) may be configured to control the wheel variable device (50, 60) of the mobile robot (1). As an example, the processor (90) may control the wheel variable device (50, 60) to switch the mobile robot (1) to a four-wheel mode or a two-wheel mode. For example, when the mobile robot (1) is in a four-wheel mode, the processor (90) may control the wheel variable device (50, 60) to switch the mobile robot (1) to a two-wheel mode. When the mobile robot (1) is in a two-wheel mode, the processor (90) may control the wheel variable device (50, 60) to switch the mobile robot (1) to a four-wheel mode.

[0229] The processor (90) may be formed in various ways as long as it can control the mobile robot (1). For example, the processor (90) may be implemented as a microprocessor, a GPU (Graphics Processing Unit), an AI (Artificial Intelligence) processor, an NPU (Neural Processing Unit), or a TCON (Time Controller). However, the processor (90) is not limited thereto, and may include one or more of a central processing unit (CPU), an MCU (Micro Controller Unit), an MPU (micro processing unit), a controller, an application processor (AP), a communication processor (CP), or an ARM processor, or may be defined by the relevant terms. In addition, the processor (90) may be implemented as a SoC (System on Chip), an LSI (Large Scale Integration) having a built-in processing algorithm, or may be implemented in the form of an ASIC (Application Specific Integrated Circuit), or an FPGA (Field Programmable Gate Array).

[0230] The mobile robot (1) may include a memory (91). The memory (91) may store map data. The map data may include information about the outdoors and information about the indoors. The map data may include information about the driving surface (100). For example, the map data may include a reference height of a step on which the mobile robot (1) must drive in four-wheel mode.

[0231] In addition, the memory (91) can store at least one instruction regarding the mobile robot (1). The memory (91) can store an O / S (Operating System) for driving the mobile robot (1). In addition, the memory (91) can store various software programs or applications for operating the mobile robot (1) according to one or more embodiments of the present disclosure.

[0232] Memory (91) may include semiconductor memory such as flash memory or magnetic storage media such as hard disk.

[0233] Meanwhile, in the present disclosure, the term memory (91) may be used to mean memory, ROM within the processor, RAM, or a memory card (e.g., micro SD card, memory stick) mounted on the mobile robot (1).

[0234] The processor (90) may be composed of one or more processors. For example, the processor (90) may perform operations of a mobile robot (1) according to one or more embodiments of the present disclosure by executing at least one instruction stored in the memory (91).

[0235] The mobile robot (1) may include a user interface (92). The mobile robot (1) according to the present embodiment may use a touch display as the user interface (92). The mobile robot (1) may output the status of the mobile robot (1) through the touch display. In addition, the mobile robot (1) may receive user instructions through the touch display. For example, the mobile robot (1) may receive a four-wheel mode command or a two-wheel mode command input by a user through the touch display.

[0236] However, the user interface (92) used in the mobile robot (1) of the present disclosure is not limited thereto. The user interface (92) may include various types of input devices. For example, the user interface (92) may include physical buttons. In this case, the physical buttons may include function keys, directional keys, and dial buttons. The physical buttons may be implemented with multiple keys.

[0237] The mobile robot (1) may include a communication interface (93). The mobile robot (1) may communicate with external devices such as a server, mobile device, etc. through the communication interface (93). The mobile robot (1) may receive an operation mode command from an external device through the communication interface (93).

[0238] The processor (90) can control the mobile robot (1) according to instructions received through the communication interface (93).

[0239] The communication interface (93) may be implemented as wireless communication. For example, the communication interface (93) may be configured to perform communication using at least one of the following communication methods: Wi-Fi, Wi-Fi Direct, Bluetooth, Zigbee, 3G (3rd Generation), 3GPP (3rd Generation Partnership Project), LTE (Long Term Evoloution), and 5G (5th Generation).

[0240] A mobile robot (1) may include a pair of front in-wheel motors (21) and a pair of rear in-wheel motors (31). The front in-wheel motor (21) may be installed on a front driving wheel (20) and may drive the front driving wheel (20). The rear in-wheel motor (31) may be installed on a rear driving wheel (30) and may drive the rear driving wheel (30). A processor (90) may control the pair of front in-wheel motors (21) and the pair of rear in-wheel motors (31) to move the mobile robot (1) in a desired direction.

[0241] A mobile robot (1) may include a driving sensor (95). A processor (90) may use a signal input from the driving sensor (95) to move the mobile robot (1) to a destination. The processor (90) may use the driving sensor (95) to avoid obstacles along the moving path. The processor (90) may use the driving sensor (95) to recognize the state of the moving path. For example, the processor (90) may use the driving sensor (95) to recognize whether the mobile robot (1) is indoors or outdoors.

[0242] The driving sensor (95) may include an ultrasonic sensor, a 3D camera, a Time of Flight (TOF) sensor, a LiDAR sensor, etc. The processor (90) can recognize the position of the mobile robot (1) using the signal input from the driving sensor (95). The processor (90) can recognize obstacles in the moving path using the signal input from the driving sensor (95).

[0243] The mobile robot (1) may include a microphone (96). The processor (90) may control the mobile robot (1) using signals input from the microphone (96). The microphone (96) is configured to convert the user's voice into an electrical signal. Accordingly, the user may control the mobile robot (1) by voice.

[0244] The mobile robot (1) may include a speaker (97). The processor (90) may output an alarm or information about the status of the mobile robot (1) through the speaker (97).

[0245] The mobile robot (1) may include a power supply (98). The power supply (98) is configured to supply power to all internal components of the mobile robot (1). For example, a rechargeable battery may be used as the power supply (98).

[0246] The processor (90) can recognize the status of the power supply (98) using a signal input from the power supply (98). The processor (90) can output the status of the power supply (98) through a speaker (97). When the power of the power supply (98) is insufficient, the processor (90) can control a pair of front in-wheel motors (21) and a pair of rear in-wheel motors (31) to move the mobile robot (1) to the charging station.

[0247] When the processor (90) recognizes that the mobile robot (1) is located outdoors using the driving sensor (95), it causes the mobile robot (1) to drive in a four-wheel mode. When the current mode of the mobile robot (1) is a two-wheel mode, the processor (90) controls the front motor (52) of the front wheel variable device (50) and the rear motor (62) of the rear wheel variable device (60) to change the two-wheel mode to a four-wheel mode. Thereafter, the processor (90) controls a pair of front in-wheel motors (21) and a pair of rear in-wheel motors (31) to drive the mobile robot (1).

[0248] If the processor (90) recognizes that the mobile robot (1) is located in a narrow or complex space based on a signal from the driving sensor (95), it causes the mobile robot (1) to drive in two-wheel mode. If the current mode of the mobile robot (1) is four-wheel mode, the processor (90) controls the front motor (52) of the front wheel variable device (50) and the rear motor (62) of the rear wheel variable device (60) to change the four-wheel mode to two-wheel mode. Thereafter, the processor (90) controls a pair of rear in-wheel motors (31) to drive the mobile robot (1).

[0249] When the processor (90) recognizes that the mobile robot (1) has passed through a narrow or complex space using the driving sensor (95), it causes the mobile robot (1) to drive in four-wheel mode. For example, the processor (90) controls the wheel variable device (50, 60) to change the two-wheel mode to four-wheel mode and controls a pair of front in-wheel motors (21) and a pair of rear in-wheel motors (31) to drive the mobile robot (1).

[0250] When the processor (90) recognizes that the mobile robot (1) is located indoors using the driving sensor (95), it causes the mobile robot (1) to drive in two-wheel mode. When the current mode of the mobile robot (1) is four-wheel mode, the processor (90) controls the wheel variable device (50, 60) to change the four-wheel mode to two-wheel mode and controls a pair of rear in-wheel motors (31) to drive the mobile robot (1).

[0251] When the processor (90) recognizes a high step of the driving surface (100) from the signal of the driving sensor (95) while driving, it controls the wheel variable device (50, 60) to switch from two-wheel mode to four-wheel mode. After the mobile robot (1) passes the high step in four-wheel mode, the processor (90) controls the wheel variable device (50, 60) to switch from four-wheel mode to two-wheel mode to drive the mobile robot (1).

[0252] When the processor (90) recognizes that excessive torque has occurred in the front in-wheel motor (21) and / or the rear in-wheel motor (31), it controls the front motor (52) of the front wheel variable device (50) and the rear motor (62) of the rear wheel variable device (60) to switch from the two-wheel mode to the four-wheel mode. When the mobile robot (1) passes over an obstacle such as a bump or a carpet, excessive torque may occur in the front in-wheel motor (21) and / or the rear in-wheel motor (31). After the mobile robot (1) passes over the obstacle in the four-wheel mode, the processor (90) controls the wheel variable devices (50, 60) to switch from the four-wheel mode to the two-wheel mode to drive the mobile robot (1).

[0253] A mobile robot (1) according to one or more embodiments of the present disclosure having a structure as described above can drive outdoors in a four-wheel mode capable of exerting powerful driving force, and indoors in a two-wheel mode capable of exerting rapid steering performance. Therefore, a mobile robot (1) according to one or more embodiments of the present disclosure can exhibit high driving performance in various indoor and outdoor environments.

[0254] In addition, a mobile robot (1) according to one or more embodiments of the present disclosure can drive in four-wheel mode when encountering an obstacle while driving indoors, thereby improving obstacle overcoming performance.

[0255] In addition, the mobile robot (1) according to one or more embodiments of the present disclosure can rotate in place in a two-wheel mode when driving indoors, so that it can effectively pass through narrow or complex spaces.

[0256] While the present disclosure has been illustrated and described above with reference to various embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the present disclosure as defined by the appended claims and their equivalents.

Claims

1. Body; A pair of front driving wheels installed at the front part of the above body; A pair of rear drive wheels installed at the rear of the above body; Four auxiliary wheels installed on the lower surface of the above body; A front wheel variable device including a front linear actuator installed on the upper part of the body; and A rear wheel variable device including a rear linear actuator installed at the lower part of the above body; The front wheel variable device and the rear wheel variable device include a wheel variable device that changes the pair of front drive wheels and the pair of rear drive wheels into one of a four-wheel mode and a two-wheel mode; In the above four-wheel mode, the pair of front drive wheels and the pair of rear drive wheels are in contact with the driving surface, and the four auxiliary wheels are separated from the driving surface. A mobile robot in which, in the two-wheel mode, the pair of front drive wheels are spaced apart from the driving surface, the pair of rear drive wheels move toward the center of the body, and the pair of rear drive wheels and the four auxiliary wheels are in contact with the driving surface.

2. In paragraph 1, The above front wheel variable device is formed to move the pair of front driving wheels up and down with respect to the body, A mobile robot, wherein the rear wheel variable device is formed to move the pair of rear drive wheels forward and backward with respect to the body.

3. In paragraph 2, A mobile robot, wherein the above front linear actuator is formed to move the pair of front driving wheels up and down.

4. In paragraph 3, The above front wheel variable device is, An upper arm having one end connected to the front linear actuator and the other end connected to the pair of front driving wheels; and A mobile robot further comprising a lower arm, one end of which is connected to the lower part of the body and the other end of which is connected to the pair of front driving wheels.

5. In paragraph 4, The above front linear actuator, front motor; a front screw rotated by the front motor; and a front nut screwed to the front screw and to which one end of the upper arm is connected; A mobile robot in which, when the above front motor rotates, one end of the above upper arm moves in a straight line along the above front screw.

6. In paragraph 4, A mobile robot, wherein the upper arm is formed by a suspension.

7. In paragraph 6, A mobile robot, wherein the above suspension includes a coil spring and a shock absorber.

8. In paragraph 2, A mobile robot, wherein the rear linear actuator is formed to move the pair of rear driving wheels back and forth with respect to the body.

9. In paragraph 8, The above body, upper support plate; A lower support plate installed below the upper support plate; and It includes an inclined block installed on the upper surface of the lower support plate and including an inclined surface; A mobile robot in which the rear linear actuator is installed on the inclined surface of the inclined block.

10. In paragraph 8, The above rear wheel variable device is, A mobile robot further comprising a support bar, one end of which is connected to the rear linear actuator and the other end of which is connected to the pair of rear driving wheels.

11. In paragraph 10, The above rear linear actuator, rear motor; a rear screw rotated by the rear motor; and A rear nut screwed to the rear screw and connected to the support bar; A mobile robot in which, when the rear motor rotates, the support bar moves in a straight line along the rear screw.

12. In paragraph 8, The above rear wheel variable device is, A fixed plate installed on the above rear linear actuator; A movable plate spaced a certain distance from the fixed plate and installed parallel to the fixed plate, and on which the pair of rear driving wheels are installed; An upper link, one end of which is rotatably installed on the fixed plate and the other end of which is rotatably installed on the movable plate; A lower link installed below the upper link, one end of which is rotatably installed on the fixed plate, and the other end of which is rotatably installed on the movable plate; and A mobile robot comprising a coil spring disposed between the upper link and the lower link.

13. In paragraph 8, The above rear wheel variable device is, A fixed plate installed on the above rear linear actuator; A movable plate spaced a certain distance from the fixed plate and installed parallel to the fixed plate, and on which one of the pair of rear drive wheels is installed; and A mobile robot, comprising a suspension installed between the moving plate and the fixed plate.

14. In paragraph 1, A mobile robot, wherein the pair of front driving wheels and the pair of rear driving wheels each include an in-wheel motor.

15. In paragraph 1, A mobile robot in which each of the above four auxiliary wheels is formed as an omni wheel.

Images