Robot and system gravity center derivation method

Abstract

The invention relates to a robot and a system gravity center derivation method. The robot includes a platform onto which an article is loaded, an actuator module connected to the platform and configured to move the platform, and a controller. The controller is configured to derive one or more of information indicative of a weight of the loaded item, or information indicative of a center of gravity of the system including the platform and the loaded item in a state in which the item is loaded onto the platform. The controller is configured to derive one or more of information indicative of a weight of the loaded item, information indicative of a horizontal position of a center of gravity of the system including the platform and the loaded item, or information indicative of a height of the center of gravity of the system based on a load applied to a partial region of the actuator module.

Description

[0001] Cross-reference of related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2024-0066622, filed on May 22, 2024, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a robot and a method for deriving the center of gravity of a system. Background Technology

[0004] Mobile robots can move items to a target location. For example, items that may need to be delivered can be loaded onto a mobile robot. The mobile robot can then deliver the loaded items to the target location.

[0005] Current mobile robots in the prior art can be manufactured with weight detection sensors to identify the weight of the loaded items. However, this approach leads to technical problems because the position of the system's center of gravity and the system's height cannot be determined solely by the weight detection sensors. Therefore, there is a problem that it is difficult to maximize the performance of the mobile robot by using only information about the system's weight. Summary of the Invention

[0006] This disclosure provides a robot capable of deriving information indicating the center of gravity of a system, including loading items and platforms. The derived information is used to switch the robot's posture and configuration to maximize its performance. Therefore, the disclosed embodiments provide technical solutions to these technical problems.

[0007] In particular, information including data related to or indicating the system's center of gravity can be used to ensure the mobile robot's driving stability. Information related to the system's center of gravity may include, but is not limited to, information about or indicating the platform set on the mobile robot, the items loaded onto the platform, and the weight of the items.

[0008] To achieve the above objectives, one aspect of this disclosure provides a robot comprising a platform on which an item is loaded, an actuator module connected to the platform and configured to move the platform, and a controller. The controller is configured to derive information indicating the weight of the loaded item, information indicating the center of gravity of the system including the platform and the loaded item in the state where the item is loaded onto the platform, or one or more of any combination thereof. The controller is configured to derive information indicating the weight of the loaded item, information indicating the horizontal position of the center of gravity of the system including the platform and the loaded item, information indicating the height of the system's center of gravity, or one or more of any combination thereof, based on a load applied to a portion of the actuator module.

[0009] Further, when the weight of the loaded article is less than a threshold allowable weight, the controller can be configured to control the actuator module to move the platform in a state where the article is loaded on the platform, and can be configured to derive the vertical height of the system center of gravity based on the movement of the platform.

[0010] Further, the controller can be configured to derive a horizontal position of the system center of gravity based on a load applied to the actuator module. When the horizontal position of the system center of gravity is a first position based on a state where the platform is placed in a first attitude oriented in a horizontal direction, and when the horizontal position of the system center of gravity is a second position based on a state where the platform is placed in a second attitude rotated by a first angle from the first attitude so that the platform is oriented to be inclined by the first angle with respect to the horizontal direction, the controller can be configured to derive a first height by comparing the first position and the second position. The first height can be the vertical height of the system center of gravity.

[0011] Further, the platform can be configured to switch from the first attitude to the second attitude when rotated by the first angle in a first rotation direction about a rotation center passing through a first position point. The first position point can correspond to a first position on the platform, and can extend in a width direction of the platform. When the horizontal position of the system center of gravity is a third position based on a state where the platform is placed in a third attitude rotated by the first angle in a second rotation direction about the rotation center from a state where the platform is placed in the first attitude, the controller can be configured to derive a second height by comparing the first position and the third position. The second rotation direction can be a direction opposite to the first rotation direction, and the second height can include the vertical height of the system. When a difference between the first height and the second height is equal to or less than a threshold, the controller can compare the first height and the second height, and determine that the loaded article is fixed to the platform.

[0012] Further, the actuator module can include a motor mounted on the platform, an eccentric arm configured to change the attitude by the motor and mounted on the motor at one end, and a wheel rotatably connected to the other end of the eccentric arm. The robot can be configured to be placed in a ground parallel attitude in which the platform is placed in the first attitude, the eccentric arm is directed toward a horizontal direction, and the other end of the eccentric arm is spaced apart from the platform in a longitudinal direction of the platform. Alternatively or additionally, the robot can be configured to be placed in a ground angle attitude in which the platform is placed in the second attitude, the eccentric arm is directed toward a direction intersecting the horizontal direction, the eccentric arm is oriented to be inclined with respect to the horizontal direction, and the other end of the eccentric arm is spaced apart from the platform in the longitudinal direction of the platform. The first position can be the horizontal position of the system center of gravity based on a state where the robot is placed in the ground parallel attitude. The second position can be the horizontal position of the system center of gravity based on a state where the robot is placed in the ground angle attitude.

[0013] Further, the actuator module can include a plurality of actuator modules. The plurality of actuator modules can include a first actuator module disposed at one longitudinal side of the platform and a second actuator module disposed at the other longitudinal side of the platform. The first actuator module can include a first-first actuator module disposed at one lateral side of the platform and can include a first-second actuator module disposed at the other lateral side of the platform. The second actuator module can include a second-first actuator module disposed at one lateral side of the platform and can include a second-second actuator module disposed at the other lateral side of the platform. Heights of the eccentric arms of the first-first actuator module and the first-second actuator module can be equal to each other. Heights of the eccentric arms of the second-first actuator module and the second-second actuator module can be equal to each other based on a state in which the robot is placed in the ground parallel posture or the ground angle posture. When the heights of the eccentric arms of the first-first actuator module and the first-second actuator module are a first driving height and the heights of the eccentric arms of the second-first actuator module and the second-second actuator module are a second driving height, the first driving height and the second driving height can be equal to each other when the robot is placed in the ground parallel posture. The first driving height and the second driving height can be different from each other when the robot is placed in the ground angle posture.

[0014] Further, the controller can be configured to derive the weight of the loaded article based on the weight of the platform in a state in which the robot is placed in the ground parallel posture, the torque applied to the motors of the plurality of actuator modules, and the length of the eccentric arm.

[0015] Further, the weight of the loaded article can be derived based on Equation 1 below.

[0016] [Equation 1]

[0017] Fa = Ma * g = ((T11 + T12 + T21 + T22) / (e * g) - Mp) * g

[0018] In Equation 1 above, Fa is the weight of the loaded article, Ma is the mass of the loaded article, Mp is the mass of the platform, T11 is the torque applied to the motor of the first-first actuator module, T12 is the torque applied to the motor of the first-second actuator module, T21 is the torque applied to the motor of the second-first actuator module, T22 is the torque applied to the motor of the second-second actuator module, e is the length of the eccentric arm, and g is the acceleration of gravity.

[0019] Further, the controller can be configured to derive the first length position based on a length of the platform in a state where the robot is placed in the ground parallel posture and torques applied to the motors of the plurality of actuator modules. The first length position can be a longitudinal position on the platform at the system center of gravity and a position spaced apart from one longitudinal end of the platform by a first length distance in the longitudinal direction and spaced apart from the other longitudinal end of the platform by a second length distance in the longitudinal direction.

[0020] Further, the first length distance and the second length distance can be derived based on Equations 2-1 and 2-2 below, respectively.

[0021] [Equation 2-1]

[0022] DL1 = (L - DL1) * (T21 + T22) / (T11 + T12)

[0023] In the above Equation 2-1, DL1 is the first length distance, L is a distance between two opposite longitudinal ends of the platform, T11 is a torque applied to the motor of the first-first actuator module, T12 is a torque applied to the motor of the first-second actuator module, T21 is a torque applied to the motor of the second-first actuator module, and T22 is a torque applied to the motor of the second-second actuator module.

[0024] [Equation 2-2]

[0025] DL2 = L - DL1

[0026] In the above Equation 2-2, DL2 is the second length distance.

[0027] Further, the controller can be configured to derive the first length position based on a length of the platform in a state where the robot is placed in the ground parallel posture and torques applied to the motors of the plurality of actuator modules. The first length position can be a longitudinal position on the platform at the system center of gravity and a position spaced apart from one longitudinal end of the platform by a first length distance in the longitudinal direction and spaced apart from the other longitudinal end of the platform by a second length distance in the longitudinal direction.

[0028] Further, the first length distance and the second length distance can be derived based on Equations 2-1 and 2-2 below, respectively.

[0029] [Equation 3-1]

[0030] DW1 = (W - DW1) * (T12 + T22) / (T11 + T21)

[0031] In Equation 3-1, DW1 is a first width distance, W is a distance between two opposite lateral ends of the platform, T11 is a torque applied to a motor of the first-first actuator module, T12 is a torque applied to a motor of the first-second actuator module, T21 is a torque applied to a motor of the second-first actuator module, and T22 is a torque applied to a motor of the second-second actuator module.

[0032] [Equation 3-2]

[0033] DW2 = W - DW1

[0034] In Equation 3-2, DW2 is a second width distance.

[0035] Further, the controller can be configured to derive a second length position based on a length of the platform in a state where the robot is placed in a ground angle posture and torques applied to the motors of the plurality of actuator modules. The second length position can be a longitudinal position on the platform at the system center of gravity, and can be a position spaced apart from one longitudinal end of the platform by a third length distance in the longitudinal direction and spaced apart from the other longitudinal end of the platform by a fourth length distance in the longitudinal direction. When the upper end of the other longitudinal side of the platform is located above one longitudinal end of the platform, the first height can be derived based on the following Equation 4.

[0036] [Equation 4]

[0037] h = (DL3 - DL1) / sin(a)

[0038] In Equation 4, h is a first height, DL3 is a third length distance, and a is a first angle.

[0039] Further, another aspect of the disclosure provides a method of deriving a system center of gravity. The method includes a loading step of loading an item onto a platform. The method further includes a center of gravity information derivation step of deriving one or more of information indicating a weight of the loaded item, information indicating a center of gravity of a system including the platform and the loaded item in a state where the item is loaded onto the platform, or any combination thereof. The center of gravity information derivation step includes deriving one or more of information indicating the weight of the loaded item, information indicating a horizontal position of the center of gravity of the system including the platform and the loaded item, information indicating a height of the system center of gravity, or any combination thereof based on a load applied to a partial area of an actuator module configured to move the platform.

[0040] Further, the center of gravity information derivation step can include a comparison step of comparing the weight of the loaded item and a threshold allowable weight. The center of gravity information derivation step can further include a height derivation step of deriving the height of the system center of gravity based on movement of the platform when the weight of the loaded item is less than the threshold allowable weight.

[0041] Further, the center of gravity information deriving step can further include a horizontal position deriving step of deriving a horizontal position of the system center of gravity. The horizontal position deriving step can include deriving a first position based on a state in which the platform is placed in a first posture oriented in a horizontal direction. The first position can be a horizontal position of the system center of gravity. When the horizontal position of the system center of gravity is a second position based on a state in which the platform is placed in a second posture rotated by a first angle from the first posture such that the platform is oriented to be inclined by the first angle with respect to the horizontal direction, the center of gravity information deriving step can include a first height deriving step of deriving a first height by comparing the first position and the second position. The first height can be a vertical height of the system center of gravity.

[0042] Further, the platform can be configured to switch from the first posture to the second posture when rotated by the first angle in a first rotation direction about a rotation center passing through a first position point. The first position point can correspond to the first position on the platform and can extend in a width direction of the platform. When the horizontal position of the system center of gravity is a third position based on a state in which the platform is placed in a third posture rotated by the first angle in a second rotation direction about the first position from a state in which the platform is placed in the first posture, the second rotation direction can be a direction opposite to the first rotation direction. The center of gravity information deriving step can further include a second height deriving step of deriving a second height by comparing the first position and the third position. The second height can be a vertical height of the system center of gravity with respect to the platform. The center of gravity information deriving step can further include a determining step of comparing the first height and the second height and determining that the loaded article is fixed to the platform when a difference between the first height and the second height is equal to or less than a threshold value.

[0043] The robot according to the present disclosure can derive information indicating a center of gravity of a system including a loaded article and a platform, and can maximize operational efficiency by using the derived information indicating the center of gravity. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 is a plan view of a robot according to an embodiment of the present disclosure.

[0045] Figure 2 is a graph showing a longitudinal position of a center of gravity of a system including a platform and a loaded article according to an embodiment of the present disclosure.

[0046] Figure 3 is a graph showing a transverse position of a center of gravity of a system including a platform and a loaded article according to an embodiment of the present disclosure.

[0047] Figure 4 is a graph showing a state in which a platform switches from a first posture to a second posture according to an embodiment of the present disclosure.

[0048] Figure 5 FIG. 1 is a diagram illustrating a state in which a platform according to an embodiment of the disclosure switches from a first posture to a third posture.

[0049] Figure 6 FIG. 2 is a flowchart illustrating a method of deriving a center of gravity of a system according to an embodiment of the disclosure.

[0050] Explanation of symbols:

[0051] 1: robot

[0052] 100: platform

[0053] 200: actuator module

[0054] 210: motor

[0055] 220: eccentric arm

[0056] 230: wheel

[0057] 201: first actuator module

[0058] 201-1: first-first actuator module

[0059] 201-2: first-second actuator module

[0060] 202: second actuator module

[0061] 202-1: second-first actuator module

[0062] 202-2: second-second actuator module

[0063] 300: controller DETAILED DESCRIPTION

[0064] Various embodiments of the disclosure are described in detail below with reference to the attached drawings. When components are given reference numerals in the respective drawings, it should be noted that the same components are designated by the same reference numerals even if they are illustrated in different drawings. Further, in the following description of embodiments of the disclosure, detailed descriptions of related known configurations or functions incorporated herein will be omitted when it is determined that such detailed description will obscure the understanding of the embodiments of the disclosure.

[0065] Further, the terms “part,” “module,” and the like in the specification refer to a unit processing at least one function or operation, which can be implemented in hardware or software or a combination of hardware and software. When a controller, component, device, element, part, unit, module, etc. of the present disclosure is described as having a purpose or performing an operation, function, etc., the controller, component, device, element, part, unit, or module should be considered as “configured to” meet the purpose or perform the operation or function herein. Each controller, component, device, element, part, unit, module, etc. can be embodied individually or included as part of a device (e.g., robot) or system with a processor and a memory such as a non-transitory computer readable medium. The processor can be a suitably programmed, e.g., via executable instructions stored in the memory, or a specially configured processor such as an FPGA or ASIC.

[0066] Robots and methods can automatically collect data about the state of the robot or system for different purposes. The state of the robot can include whether an item is loaded on the platform of the robot, whether the robot is placed or set on a pose on a surface, e.g., whether a controller or processor causes the robot to assume a pose or position, whether the robot switches from one pose to another, e.g., whether a controller or processor causes the robot to switch from one position or pose to another, etc. The current, previous, or future state, or changes / transitions therebetween, can be used to determine or derive various information as described below. It should be understood that these states can be referred to with other terminology, and that fewer or more states or sub-states can be implemented by the robot or method depending on the implementation.

[0067] Robot 1

[0068] As Figure 1 shown, a robot 1 according to the present disclosure is described below with reference to the accompanying drawings.

[0069] Figure 1 is a top plan view of a robot 1 according to an embodiment of the present disclosure. Figure 2 is a graph showing the longitudinal position of the center of gravity of a system including a platform and a loaded item according to an embodiment of the present disclosure. Figure 3 is a graph showing the lateral position of the center of gravity of a system including a platform and a loaded item according to an embodiment of the present disclosure.

[0070] Referring to Figures 1 to 3, the robot 1 can travel along the ground. The robot 1 can deliver a loaded article that can need to be delivered to a target location. The loaded article can refer to an article loaded on a platform 100, which is further described below. The robot 1 can be referred to as a "delivery robot" or a "mobile robot". The robot 1 can include the platform 100, an actuator module 200, and a controller 300. The controller 300 can include a processor as described above. The actuator module 200 can be implemented by the controller 300 or the separate processor described above.

[0071] The loaded article can be seated on the platform 100. The platform 100 can be supported by the actuator module 200. In addition, the platform 100 can be disposed to be spaced upward from the ground. Referring to Figure 2 , the platform 100 can be placed in a first attitude oriented in a horizontal direction.

[0072] Figure 4 is a diagram illustrating a state in which the platform 100 according to an embodiment of the disclosure is switched from the first attitude to a second attitude. Figure 5 is a diagram illustrating a state in which the platform is switched from the first attitude to a third attitude according to an embodiment of the disclosure.

[0073] Referring to Figure 4 and Figure 5 , the platform 100 can be switched from the first attitude and can be placed in a second attitude or a third attitude oriented to be inclined with respect to the horizontal direction.

[0074] Referring to Figure 4 , when rotated by a first angle a in a first rotation direction about a rotation center passing through a corresponding point X, the platform 100 placed in the first attitude can be switched from the first attitude to the second attitude. The corresponding point X refers to a first position point corresponding to a first position on the platform 100 and extending in a leftward or rightward direction. The first position can refer to a horizontal position of a center of gravity CG (shown in Figure 2 and Figure 3 ) of a system including the platform 100 and the loaded article based on a state in which the platform 100 is placed in the first attitude. In addition, the corresponding point X can refer to a first position point intersecting a straight line passing through the first position on the upper surface of the platform 100 and extending in an upward or downward direction H.

[0075] In addition, when the right side of the robot 1 is viewed in parallel with the leftward or rightward direction, the first rotation direction can refer to a clockwise direction. For example, when the platform 100 is placed in the second attitude, the platform 100 can be oriented to be inclined such that the center of the front end is located below the center of the rear end of the platform 100.

[0076] Referring to Figure 5The platform 100 placed in the first attitude can be switched from the first attitude to a third attitude by rotating about the first position X (i.e., the center of rotation) in a second rotational direction to generate a first angle. The second rotational direction can be defined as, i.e., means or includes a direction opposite to the first rotational direction. For example, when the platform 100 is placed in the third attitude, the platform 100 can be oriented to be tilted such that the center of the front end is located above the center of the rear end of the platform 100.

[0077] The actuator module 200 can move the platform 100 relative to the ground. The actuator module 200 can be controlled by the controller 300. The actuator module 200 can be provided as a plurality of actuator modules 200. The plurality of actuator modules 200 can include a first actuator module 201 and a second actuator module 202.

[0078] The first actuator module 201 can be provided at one longitudinal side of the platform 100. In the present specification, the longitudinal direction can be defined as, i.e., means or includes a forward or rearward direction. For example, the first actuator module 201 can be provided at the front side of the platform 100. The first actuator module 201 can be provided as a plurality of first actuator modules 201. The plurality of first actuator modules 201 can include a first-first actuator module 201-1 and a first-second actuator module 201-2.

[0079] The first-first actuator module 201-1 and the first-second actuator module 201-2 can be spaced apart from each other in a width direction. In the present specification, the width direction can be defined as, i.e., means or includes a leftward or rightward direction. The first-first actuator module 201-1 can be provided at one lateral side of the platform 100. For example, the first-first actuator module 201-1 can be provided at the left front side of the platform 100. In addition, the first-second actuator module 201-2 can be provided at the other lateral side of the platform 100. For example, the first-second actuator module 201-2 can be provided at the right front side of the platform 100.

[0080] The second actuator module 202 can be provided at the other longitudinal side of the platform 100. For example, the second actuator module 202 can be provided at the rear side of the platform 100. The second actuator module 202 can be provided as a plurality of second actuator modules 202. The plurality of second actuator modules 202 can include a second-first actuator module 202-1 and a second-second actuator module 202-2.

[0081] The second-first actuator module 202-1 and the second-second actuator module 202-2 can be spaced apart from each other in the width direction. The second-first actuator module 202-1 can be disposed at one lateral side of the platform 100. For example, the second-first actuator module 202-1 can be disposed at the left rear side of the platform 100. The second-second actuator module 202-2 can be disposed at the other lateral side of the platform 100. For example, the second-second actuator module 202-2 can be disposed at the right rear side of the platform 100.

[0082] The first-first actuator module 201-1, the first-second actuator module 201-2, the second-first actuator module 202-1, and the second-second actuator module 202-2 can each include a motor 210, an eccentric arm 220, and a wheel 230.

[0083] The motor 210 can include a stator, a rotor, and a rotation shaft, and operate by being supplied with power from the outside (e.g., an external source). The motor 210 can power the eccentric arm 220 and the wheel 230 to rotate the eccentric arm 220 and the wheel 230.

[0084] The eccentric arm 220 can allow or cause the center of the motor 210 and the center of the wheel 230 to be spaced apart from each other. For example, one end of the eccentric arm 220 can be connected to the rotation shaft of the motor 210, and the other end of the eccentric arm 200 can be rotatably connected to the center of the wheel 230. One end of the eccentric arm 220 can be configured to rotate about a rotation axis extending in the lateral direction, and the other end of the eccentric arm 220 can be disposed to rotate about a rotation axis extending in the lateral direction.

[0085] Further, the heights of the eccentric arms 220 of the first-first actuator module 201-1 and the first-second actuator module 201-2 can be equal to each other based on the state in which the robot 1 is placed in the floor parallel posture or the floor angle posture described below. Further, the heights of the eccentric arms 220 of the second-first actuator module 202-1 and the second-second actuator module 202-2 can be equal to each other.

[0086] Further, the heights of the eccentric arms 220 of the first-first actuator module 201-1 and the first-second actuator module 201-2 can be referred to as a first driving height. The heights of the eccentric arms 220 of the second-first actuator module 202-1 and the second-second actuator module 202-2 can be referred to as a second driving height.

[0087] When the robot 1 is placed in the floor parallel posture, the first driving height and the second driving height can be equal to each other. Further, when the robot 1 is placed in the floor angle posture, the first driving height and the second driving height can be different from each other.

[0088] The wheel 230 can be configured to rotate with respect to the other end of the eccentric arm 220. Also, the center of the wheel 230 can be configured to rotate with respect to one end of the eccentric arm 220. The wheel 230 can include a rim, a tire, etc.

[0089] The system or robot 1 can include one or more measurement subsystems (not shown) coupled to the controller 300. Each of the one or more measurement subsystems can include one or more sensors, transceivers, etc., to sense or otherwise measure one or more physical or environmental parameters, e.g., analog parameters, or to receive / detect external signals, e.g., position signals such as GPS transmissions, which can vary in accordance with operation of the system or robot 1, and as described above, generate or derive “measurement” data indicative thereof.

[0090] In a state in which the loaded article is seated on the platform 100, the controller 300 can derive information indicative of a weight of the loaded article and information indicative of a center of gravity CG of the system including the loaded article and the platform 100. Based on a partial region of the actuator module 200 (e.g., a load applied to a shaft of the motor 210), the controller 300 can derive one or more of the information indicative of the weight of the loaded article, the information indicative of the center of gravity CG of the system including the platform 100 and the loaded article, or any combination thereof.

[0091] For example, based on a load current value, i.e., a current value flowing through the motor 210 provided in each of the plurality of actuator modules 200, the controller 300 can derive the information indicative of the weight of the loaded article and the information indicative of the center of gravity CG of the system including the platform 100 and the loaded article.

[0092] In a more detailed example, assuming that a torque applied to a rotational shaft of the motor 210 by the wheel 230, the platform 100, and the loaded article is an external force torque, the load current value can refer to, i.e., refer to a current value applied to the motor 210 to generate a torque (a torque having a magnitude equal to that of the external force torque and a direction opposite to that of the external force torque) for canceling the external force torque so as to prevent the rotational shaft of the motor 210 from rotating due to the external force torque.

[0093] Based on a state in which the robot 1 is placed in the ground parallel posture, the controller 300 can derive the weight of the loaded article based on a weight of the platform 100, currents applied to the plurality of motors 210, and a length of the eccentric arm 220. When the robot 1 is placed in the ground parallel posture, the platform 100 can be placed in the first posture, and a longitudinal separation distance between the wheel 230 (e.g., the other end of the eccentric arm 220) of the first actuator module 201 and the wheel 230 (e.g., the other end of the eccentric arm 220) of the second actuator module 202 can be maximized.

[0094] For example, the controller 300 can derive the torque applied to the plurality of motors 210 based on the current applied to the plurality of motors 210.

[0095] In another example, the robot 10 can further include a torque sensor configured to measure the torque applied to the plurality of motors 210. For example, the torque sensor can be provided, i.e., can include a plurality of torque sensors. The plurality of torque sensors can measure the torque applied to the plurality of motors 210. The torque applied to the plurality of motors 210 can include a plurality of torques including the torques T11, T12, T21, and T22 as described below. The plurality of torque values measured by the plurality of torque sensors can be transmitted to the controller 300. The plurality of torque sensors can be electrically connected to the controller 300.

[0096] The controller 300 can derive the weight F of the system based on the torque applied to the plurality of motors 210 and the length of the eccentric arm 220. In addition, the controller 300 can derive the mass Ma of the loaded article from the weight F of the system and the mass Mp input from the platform in advance.

[0097] For example, the controller 300 can derive the weight of the loaded article based on Equation 1 below.

[0098] [Equation 1]

[0099] Fa = Ma * g = ((T11 + T12 + T21 + T22) / (e * g) - Mp) * g

[0100] In Equation 1 above, Fa is the weight of the loaded article, Ma is the mass of the loaded article, Mp is the platform mass, T11 is the torque applied to the motor of the first-first actuator module, T12 is the torque applied to the motor of the first-second actuator module, T21 is the torque applied to the motor of the second-first actuator module, T22 is the torque applied to the motor of the second-second actuator module, e is the length of the eccentric arm, and g is the acceleration of gravity.

[0101] The controller 300 can compare the weight of the loaded article with a threshold allowable weight. The threshold allowable weight can refer to the maximum weight of the loaded article allowed to be seated on the robot 1. For example, when the weight of the loaded article is less than the threshold allowable weight, the controller 300 can control the actuator module 200 so that the platform 100 moves in a state in which the article is loaded on the platform 100. In addition, when the weight of the loaded article is equal to or greater than the threshold allowable weight, the controller 300 can transmit a notification to an external device. The notification can indicate that the weight of the loaded article is greater than the threshold allowable weight.

[0102] Further, based on the state in which the robot 1 is placed in the floor parallel posture, the controller 300 can derive a first length position, which is a longitudinal position of the system center of gravity CG on the platform 100, based on a length of the platform 100 and currents applied to the plurality of motors 210.

[0103] The first length position can be defined as a position spaced apart from one longitudinal end (e.g., a front end) of the platform 100 by a first length distance DL1 in the longitudinal direction. Further, the first length position can be defined as a position spaced apart from the other longitudinal end (e.g., a rear end) of the platform 100 by a second length distance DL2 in the longitudinal direction.

[0104] The first length distance DL1 and the second length distance DL2 can be derived based on Equations 2-1 and 2-2 below, respectively.

[0105] [Equation 2-1]

[0106] DL1 = (L - DL1) * (T21 + T22) / (T11 + T12)

[0107] In the above Equation 2-1, DL1 is the first length distance, L is a distance between two opposite longitudinal ends of the platform, T11 is a torque applied to a motor of the first-first actuator module, T12 is a torque applied to a motor of the first-second actuator module, T21 is a torque applied to a motor of the second-first actuator module, and T22 is a torque applied to a motor of the second-second actuator module.

[0108] [Equation 2-2]

[0109] DL2 = L - DL1

[0110] In the above Equation 2-2, DL2 is the second length distance.

[0111] Further, based on the state in which the robot 1 is placed in the floor parallel posture, the controller 300 can derive a first width position, which is a lateral position of the system center of gravity CG on the platform 100, based on a width of the platform 100 and currents applied to the plurality of motors 210.

[0112] The first width position can be defined as a position spaced apart from one lateral end (e.g., a left end) of the platform 100 by a first width distance DW1 in the width direction. Further, the first width position can be defined as a position spaced apart from the other lateral end (e.g., a right end) of the platform 100 by a second width distance DW2 in the width direction.

[0113] The first width distance DW1 and the second width distance DW2 can be derived based on Equations 3-1 and 3-2 below, respectively.

[0114] [Equation 3-1]

[0115] DW1 = (W - DW1) * (T12 + T22) / (T11 + T21)

[0116] In the above Equation 3-1, DW1 is a first width distance, W is a distance between two opposite lateral ends of the platform, T11 is a torque applied to a motor of the first-first actuator module, T12 is a torque applied to a motor of the first-second actuator module, T21 is a torque applied to a motor of the second-first actuator module, and T22 is a torque applied to a motor of the second-second actuator module.

[0117] [Equation 3-2]

[0118] DW2 = W - DW1

[0119] In the above Equation 3-2, DW2 is a second width distance.

[0120] Further, based on a state in which the robot 1 is placed in the ground angle posture, the controller 300 can derive a second length position, i.e., a longitudinal position of the system center of gravity CG on the platform 100, based on a length of the platform 100 and the torques applied to the plurality of motors 210.

[0121] When the robot 1 is placed in the ground angle posture, the platform 100 can be placed in a second posture, and the other end of each of the plurality of eccentric arms 220 (e.g., the center of each of the plurality of wheels 230) can be placed in a state spaced apart from the platform 100 in the longitudinal direction.

[0122] The second length position can be defined as a position spaced apart from one longitudinal end (e.g., a front end) of the platform 100 by a third length distance DL3 in the longitudinal direction. Further, the second length position can be defined as a position spaced apart from the other longitudinal end (e.g., a rear end) of the platform 100 by a fourth length distance DL4 in the longitudinal direction.

[0123] The third length distance DL3 and the fourth length distance DL4 can be derived by a method corresponding to the above Equations 2-1 and 2-2. For example, when the robot 1 is placed in the ground angle posture, the third length distance DL3 and the fourth length distance DL4 can be derived based on the torques applied to the plurality of motors 210 and a distance L' between two opposite longitudinal ends of the platform 100.

[0124] The controller 300 can derive the first height H, which is the vertical height of the system's center of gravity CG, by comparing the first position and the second position. In other words, the first height H can refer to or include the vertical height of the system's center of gravity CG. The second position can be defined as the horizontal position of the system's center of gravity CG based on the state in which the platform 100 is placed in the second posture.

[0125] In a case where one longitudinal side (e.g., the upper end of the front side) of the platform 100 is located above the other longitudinal end of the platform, the controller 300 can derive the first height H, which is the height of the system's center of gravity CG when the robot 1 is placed in the ground parallel posture, based on the following Equation 4. In other words, the first height H can refer to or include the height of the system's center of gravity CG when the robot 1 is placed in the ground parallel posture.

[0126] [Equation 4]

[0127] h = R / sin(a), R = DL3 - DL1

[0128] In Equation 4 described above, h is the first height, DL3 is the third length distance, R is the amount of change in the longitudinal position of the system's center of gravity, and a is the first angle.

[0129] The amount of change R in the longitudinal position of the system's center of gravity can mean, that is, refer to, the longitudinal interval distance between the initial position P1 of the system's center of gravity CG and the changed position P2 of the system's center of gravity CG.

[0130] When the right side of the robot 1 is observed in parallel with the left or right direction, the first angle a can be defined as, that is, can refer to or can include, the angle between a first reference straight line passing through the corresponding point X and the initial position P1 and a second reference straight line passing through the corresponding point X and the changed position P2.

[0131] Further, the controller 300 can derive the second height, which is the vertical height of the system, by comparing the first position and the third position. In other words, the second height can refer to or include the vertical height of the system. The third position can be defined as, that is, can refer to or can include, the horizontal position of the system's center of gravity CG based on the state in which the platform 100 is placed in the third posture.

[0132] The controller 300 can derive the second height, which is the vertical height of the system, by comparing the first position and the third position. In other words, the second height can refer to or include the vertical height of the system. Further, in a case where a difference between the first height H and the second height is equal to or less than a threshold value or 0, the controller 300 can compare the first height H with the second height and determine that the loaded article is fixed to the platform 100. For example, when the first height H and the second height are equal to each other, the controller 300 can determine that the loaded article is fixed to the platform 100. Further, when the difference between the first height H and the second height is greater than the threshold value, the controller 300 can transmit a notification indicating that the loaded article is not properly fixed. The notification can be transmitted to the outside, i.e., an external device. In response, the controller 300 can cause the robot 1 to take an action, e.g., move the platform 100, switch a posture, etc., to address the problem and ensure the travel stability of the robot 1.

[0133] In other words, when the platform 100 is switched from the first posture to the second posture, the controller 300 can derive the first height H. When the platform 100 is switched from the first posture to the third posture, the controller 300 can derive the second height. When an error between the first height H and the second height is within a threshold value, the controller 300 can determine that the loaded article is securely fixed to the platform 100.

[0134] The controller 300 can be electrically connected to the actuator module 200 and implemented as a process for decoding and executing instructions based on input information.

[0135] Method S10 of deriving the system barycenter

[0136] Hereinafter, a method S10 of deriving a system center of gravity according to an embodiment of the disclosure will be described with reference to the accompanying drawings. Figure 6 The method S10 of deriving a system center of gravity according to an embodiment of the disclosure will be described with reference to the accompanying drawings.

[0137] Figure 6 is a flowchart illustrating a method of deriving a system center of gravity according to an embodiment of the disclosure.

[0138] The method S10 of deriving a system center of gravity can include a loading step S100 and a center of gravity information derivation step S200, S300, S400, S500, S600, S700, S800, and S900.

[0139] In the loading step S100, an article can be loaded onto the platform 100.

[0140] In the center of gravity information derivation step S200, S300, S400, S500, S600, S700, S800, and S900, one or more of information indicating a weight of the loaded article, information indicating a system center of gravity, or any combination thereof can be derived in a state in which the article is loaded onto the platform 100.

[0141] For example, in the center-of-gravity information derivation steps S200, S300, S400, S500, S600, S700, S800, and S900, one or more of information indicating the weight of the loaded article, information indicating the horizontal position of the system center of gravity, information indicating the height of the system center of gravity, or any combination thereof can be derived based on the load applied to the partial region of the actuator module 200.

[0142] The center-of-gravity information derivation steps can include the first posture control step S200, the weight derivation step S300, the comparison step S400, the horizontal position derivation step S500, the second posture control step S600, the first height derivation step S700, the third posture control step S800, the second height derivation step S900, and the determination step S1000.

[0143] In the first posture control step S200, the platform 100 can be placed in a first posture such that the robot 1 is placed in a ground parallel posture. For example, the first posture control step S200 can be executed after the loading step S100.

[0144] In the weight derivation step S300, the weight of the loaded article can be derived. The weight of the loaded article can be derived based on the above-described Equation 1. For example, the weight derivation step S300 can be executed after the first posture control step S200.

[0145] In the comparison step S400, the weight of the loaded article and the threshold allowable weight can be compared with each other. When the comparison result in the comparison step S400 indicates that the weight of the loaded article is less than the threshold allowable weight, the horizontal position derivation step S500 can be executed. In addition, when the comparison result in the comparison step S400 indicates that the weight of the loaded article is equal to or greater than the threshold allowable weight, the loading step S100 can be executed again. For example, the comparison step S400 can be executed after the weight derivation step S300.

[0146] In the horizontal position derivation step S500, the horizontal position of the system center of gravity CG can be derived. For example, in the horizontal position derivation step S500, the first position can be derived.

[0147] In the second posture control step S600, an operation in which the platform 100 is switched from the first posture to a second posture can be executed. In the second posture control step S600, a second position, which is the horizontal position of the system center of gravity CG, can be derived based on a state in which the platform 100 is placed in the second posture. For example, the second posture control step S600 can be executed after the horizontal position derivation step S500.

[0148] In the first height deriving step S700, the first height H, which is the vertical height of the system center of gravity CG, can be derived by comparing the first position and the second position. The first height H can be derived based on Equation 4 described above. For example, the first height deriving step S700 can be performed after the second posture control step S600.

[0149] In the third posture control step S800, an operation of switching the platform 100 from the first posture to the third posture can be performed. In the third posture control step S800, the third position, which is the horizontal position of the system center of gravity CG, can be derived based on a state in which the platform 100 is placed in the third posture. For example, the third posture control step S800 can be performed after the first height deriving step S700.

[0150] In the second height deriving step S900, the second height, which is the vertical height of the system center of gravity CG, can be derived by comparing the first position and the third position. For example, the second height deriving step S900 can be performed after the third posture control step S800.

[0151] In the determining step S1000, it can be determined whether the loaded article is fixed to the platform 100 by comparing the first height H and the second height. For example, in the determining step S1000, it can be determined whether a difference between the first height H and the second height is equal to or less than a threshold value or greater than the threshold value. In the determining step S1000, when the difference between the first height H and the second height is equal to or less than the threshold value (for example, 0), it can be determined that the loaded article is fixed to the platform 100. Also, in the determining step S1000, when the difference between the first height H and the second height is greater than the threshold value, it can be determined that the loaded article is not fixed to the platform 100.

[0152] All constituent elements constituting the embodiments of the present disclosure can be coupled or operated by combination in whole, but the present disclosure is not necessarily limited to this embodiment. That is, one or more constituent elements can be selectively combined and operated within the purpose of the present disclosure. Also, unless explicitly described to the contrary, the words "comprise", "include", or "have" and variations such as "comprises", "comprising", "includes", "including", "has" or "having" should be understood to imply including but not limited to. Unless otherwise defined, all terms including technical or scientific terms can have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. Terms such as those defined in a generally used dictionary can be interpreted to have a meaning consistent with the meaning in the context of the relevant technology, and unless explicitly defined in the present disclosure, can not be interpreted as an ideal or overly formal meaning.

[0153] The above description is simply given to explain the technical spirit of the present disclosure. It should be understood by those of ordinary skill in the art to which the present disclosure belongs that various changes and modifications can be made without departing from the essential characteristics of the present disclosure. Therefore, the embodiments disclosed in the present disclosure are for illustrative purposes only, but are not intended to limit the technical spirit of the present disclosure. The scope of the technical spirit of the present disclosure is not limited to this. The scope of protection of the present disclosure should be interpreted based on the appended claims. All technical spirits within the equivalent scope should be interpreted as falling within the scope of the present disclosure.

Claims

1. A robot, wherein, include: The platform on which items are loaded; An actuator module connected to the platform and configured to move the platform; and The controller is configured to The derivation indicates information about the weight of the loaded item, information about the system's center of gravity, including the platform and the loaded item, in the state where the item is loaded onto the platform, or one or more of any combination thereof, and Based on the load applied to a portion of the actuator module, information indicating the weight of the loaded item, information indicating the horizontal position of the system's center of gravity including the platform and the loaded item, information indicating the height of the system's center of gravity, or one or more of any combination thereof, is derived.

2. The robot according to claim 1, wherein, When the weight of the loaded item is less than a threshold allowable weight, the controller controls the actuator module to move the platform while the item is loaded onto the platform. The controller is configured to derive the vertical height of the system's center of gravity based on the platform's movement.

3. The robot according to claim 2, wherein, The controller is configured to deduce the horizontal position of the system's center of gravity based on the load applied to the actuator module. When the horizontal position of the system's center of gravity is a first position based on the platform being placed in a first posture oriented in the horizontal direction, and when the horizontal position of the system's center of gravity is a second position based on the platform being placed in a second posture rotated from the first posture by a first angle so that the platform is oriented to be tilted by the first angle relative to the horizontal direction, the controller is configured to derive a first height by comparing the first position and the second position, wherein the first height is the vertical height of the system's center of gravity.

4. The robot according to claim 3, wherein, The platform is configured to switch from a first posture to a second posture when it rotates by the first angle about a rotation center passing through a first position point along a first rotation direction, the first position point corresponding to a first position on the platform and extending in the width direction of the platform. When the horizontal position of the system's center of gravity is based on a third position of the platform in a third position, where the platform is positioned in the first posture and rotated by the first angle around the rotation center in a second rotation direction, the controller is configured to derive a second height by comparing the first position and the third position, wherein the second rotation direction is opposite to the first rotation direction, and the second height is the vertical height of the system. The controller compares the first height and the second height, and determines that the loaded item is fixed to the platform when the difference between the first height and the second height is equal to or less than a threshold.

5. The robot according to claim 3, wherein, The actuator module includes: The motor mounted on the platform; An eccentric arm, configured to change posture via the motor, and one end mounted on the motor; and A wheel rotatably connected to the other end of the eccentric arm. The robot is configured to The platform is placed in a ground-parallel orientation, wherein the platform is positioned in the first orientation, the eccentric arm faces the horizontal direction, and the other end of the eccentric arm is spaced apart from the platform in the longitudinal direction of the platform; and The platform is positioned at a ground-angled orientation, wherein the platform is positioned in the second orientation, the eccentric arm is oriented in a direction intersecting the horizontal direction, the eccentric arm is oriented to be inclined relative to the horizontal direction, and the other end of the eccentric arm is spaced apart from the platform in the longitudinal direction of the platform. The first position is the horizontal position of the system's center of gravity based on the robot's position in a parallel posture to the ground. The second position is the horizontal position of the system's center of gravity based on the state in which the robot is positioned at the ground angle.

6. The robot according to claim 5, wherein, The actuator module includes multiple actuator modules. The plurality of actuator modules include: A first actuator module is disposed on a longitudinal side of the platform; and The second actuator module is located on the other longitudinal side of the platform. The first actuator module includes: A first-first actuator module disposed on a lateral side of the platform; and The first and second actuator modules are disposed on the other lateral side of the platform, the second actuator module comprising: A second-first actuator module disposed on one lateral side of the platform; and The second-second actuator module is located on the other lateral side of the platform. Based on the robot's placement in either a ground-parallel or ground-angled orientation, the heights of the eccentric arms of the first-first actuator module and the first-second actuator module are equal, and the heights of the eccentric arms of the second-first actuator module and the second-second actuator module are also equal. When the height of the eccentric arm of the first-first actuator module and the first-second actuator module is a first drive height, and the height of the eccentric arm of the second-first actuator module and the second-second actuator module is a second drive height, the first drive height and the second drive height are equal when the robot is placed in the parallel posture to the ground, and the first drive height and the second drive height are different when the robot is placed in the angle posture to the ground.

7. The robot according to claim 6, wherein, The controller is configured to deduce the weight of the loaded item based on the weight of the platform when the robot is placed in a parallel position to the ground, the torque applied to the motors of the plurality of actuator modules, and the length of the eccentric arm.

8. The robot according to claim 7, wherein, The weight of the loaded items is derived based on the following Equation 1. [Equation 1] Fa=Ma*g=((T11+T12+T21+T22) / (e*g)-Mp)*g Fa is the weight of the loaded item, Ma is the mass of the loaded item, Mp is the mass of the platform, T11 is the torque applied to the motor of the first-first actuator module, T12 is the torque applied to the motor of the first-second actuator module, T21 is the torque applied to the motor of the second-first actuator module, T22 is the torque applied to the motor of the second-second actuator module, e is the length of the eccentric arm, and g is the acceleration due to gravity.

9. The robot according to claim 6, wherein, The controller is configured to derive a first length position based on the length of the platform when the robot is positioned in a ground-parallel orientation and the torque applied to the motors of the plurality of actuator modules. The first length position is a longitudinal position on the platform at the center of gravity of the system, and is a position that is spaced apart from one longitudinal end of the platform by a first length distance in the longitudinal direction and spaced apart from the other longitudinal end of the platform by a second length distance in the longitudinal direction.

10. The robot according to claim 9, wherein, The first length distance and the second length distance are derived based on the following equations 2-1 and 2-2, respectively. [Equation 2-1] DL1=(L-DL1)*(T21+T22) / (T11+T12) DL1 is the first length distance, L is the distance between the two opposite longitudinal ends of the platform, T11 is the torque applied to the motor of the first-first actuator module, T12 is the torque applied to the motor of the first-second actuator module, T21 is the torque applied to the motor of the second-first actuator module, and T22 is the torque applied to the motor of the second-second actuator module. [Equation 2-2] DL2 = L - DL1 DL2 is the second length distance.

11. The robot according to claim 6, wherein, The controller is configured to derive a first width position based on the width of the platform when the robot is positioned in a ground-parallel posture and the torque applied to the motors of the plurality of actuator modules. The first width position is a lateral position on the platform at the center of gravity of the system, and is a position that is spaced apart from one lateral end of the platform by a first width distance in the width direction, and spaced apart from the other lateral end of the platform by a second width distance in the width direction.

12. The robot according to claim 11, wherein, The first width distance and the second width distance are derived based on the following equations 3-1 and 3-2, respectively. [Equation 3-1] DW1=(W-DW1)*(T12+T22) / (T11+T21) DW1 is the first width distance, W is the distance between the two opposite lateral ends of the platform, T11 is the torque applied to the motor of the first-first actuator module, T12 is the torque applied to the motor of the first-second actuator module, T21 is the torque applied to the motor of the second-first actuator module, and T22 is the torque applied to the motor of the second-second actuator module. [Equation 3-2] DW2 = W - DW1 DW2 is the second width distance.

13. The robot according to claim 9, wherein, The controller is configured to derive a second length position based on the length of the platform when the robot is positioned at the ground angle and the torque applied to the motors of the plurality of actuator modules. The second length position is a longitudinal position on the platform at the system's center of gravity, and is a position spaced apart from one longitudinal end of the platform by a third length distance in the longitudinal direction, and from the other longitudinal end of the platform by a fourth length distance in the longitudinal direction. When the upper end of the other longitudinal side of the platform is located above one longitudinal end of the platform, the first height is derived based on the following Equation 4. [Equation 4] h=(DL3-DL1) / sin(a) h is the first height, DL3 is the third length distance, and a is the first angle.

14. A method for deriving the center of gravity of a system, wherein, The method includes: The loading step, which loads items onto the platform; and The center of gravity information derivation step indicates information about the weight of the loaded item, information about the center of gravity of the system including the platform and the loaded item in the state where the item is loaded onto the platform, or one or more of any combination thereof. The center of gravity information derivation step includes, based on a load applied to a portion of the actuator module configured to move the platform, deriving information indicating the weight of the loaded item, information indicating the horizontal position of the center of gravity of the system including the platform and the loaded item, information indicating the height of the system's center of gravity, or one or more of any combination thereof.

15. The method according to claim 14, wherein, The steps for deriving the center of gravity information include: The comparison step compares the weight of the loaded items with a threshold allowable weight; and The height derivation step involves deriving the height of the system's center of gravity based on the platform's movement when the weight of the loaded item is less than the threshold allowable weight.

16. The method according to claim 15, wherein, The step of deriving the center of gravity information further includes a horizontal position derivation step for deriving the horizontal position of the system's center of gravity. The horizontal position derivation step includes deriving a first position based on the platform being placed in a first posture oriented in the horizontal direction, wherein the first position is the horizontal position of the system's center of gravity. When the horizontal position of the system's center of gravity is based on a second position where the platform is placed in a second position rotated from the first position by a first angle so that the platform is oriented to be tilted by the first angle relative to the horizontal direction, the center of gravity information derivation step includes a first height derivation step that derives a first height by comparing the first position and the second position, wherein the first height is the vertical height of the system's center of gravity.

17. The method according to claim 16, wherein, The platform is configured to switch from a first posture to a second posture when it rotates by the first angle about a rotation center passing through a first position point along a first rotation direction, the first position point corresponding to a first position on the platform and extending in the width direction of the platform. When the horizontal position of the system's center of gravity is based on the third position of the platform in a third posture, which is a state in which the platform is rotated by a first angle around the first position along a second rotation direction, the second rotation direction is the opposite direction to the first rotation direction. The centroid information derivation step further includes: The second height derivation step derives the second height by comparing the first position and the third position, wherein the second height is the vertical height of the system's center of gravity relative to the platform; and The determination step involves comparing the first height and the second height, and determining that the loaded item is secured to the platform when the difference between the first height and the second height is equal to or less than a threshold.

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