Control method for driving stabilization of mobile robot

Abstract

Disclosed is a control method for driving stabilization of a mobile robot according to an embodiment of the present invention, wherein the mobile robot (10) comprises: a first stabilizer (30) in which a first flywheel (35) rotates at a high speed inside a first case (34) and an inclination of the first case (34) is controlled on the basis of a pitch (Y) axis; a second stabilizer (40) in which a second flywheel (45) rotates at a high speed in a direction opposite to the first flywheel (35) inside a second case (44) and an inclination of the second case (44) is controlled on the basis of a roll (X) axis; a base frame (14) on which the first and second stabilizers (30, 40) are installed; a body frame (12) on which the base frame (14) is installed; and first to fourth weight sensors (21-24) installed on the body frame (12) to measure the weight of a mounting device (100), wherein the center of mass (COM) coordinates of the mobile robot (10) are set in advance, ZMP coordinates (P x , P y ) are calculated on the basis of each weight value measured by the first to fourth weight sensors (21-24) , and a first torque ( τ f r ) is generated in the first stabilizer (30) or a second torque ( τ rr ) is generated in the second stabilizer (40) so that the ZMP coordinates approach the center of mass (COM) coordinates.

Description

Control method for driving stabilization of a mobile robot

[0001] The present invention relates to a control method for stabilizing the driving of a mobile robot when the center of gravity of the mounting device is at an arbitrary position, the mounting device is mounted on a mobile robot, and the mobile robot is driving.

[0002] Typically, mobile robots are equipped with a controller, a battery, a motor, and wheels, and can be equipped with various payloads depending on the intended use, and the payloads can operate to perform special purposes.

[0003] Mobile robots can be used for a variety of purposes, including, for example, quarantine robots for disinfection work, serving robots for food delivery, security robots for patrol surveillance, and firefighting robots for firefighting.

[0004] The payload may include a medicine tank and pump if it is a quarantine robot, a box for storing food if it is a serving robot, a camera and lighting device if it is a security robot, and a firefighting device including a fire extinguisher if it is a firefighting robot.

[0005] The above described payloads may have different centers of gravity, and the center of gravity may change frequently, especially when moving items such as soup dishes, beverages, and liquid-based items.

[0006] That is, when a mobile robot is driving, it may experience problems such as tilting or falling over depending on the center of gravity of the payload, making driving unstable.

[0007] Furthermore, the road surface on which a mobile robot travels can contain a variety of undefined obstacles. Examples of obstacles include damaged road surfaces, forming potholes, or objects lying along the path. One day, an object may be cleared, while another day, a new object may appear.

[0008] As previously explained, mobile robots have the problem of unstable driving, such as rattling or lurching when passing through obstacles in their path.

[0009] [Prior Art Literature]

[0010] [Patent Document]

[0011] (Patent Document 1) KR 10-2391562 B1

[0012] (Patent Document 2) KR 10-1740249 B1

[0013] (Patent Document 3) KR 10-2007-0072314 A

[0014] (Patent Document 4) KR 10-0685339 B1

[0015] (Patent Document 5) KR 10-2020-0053959 A

[0016] The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to provide a control method for stabilizing the driving of a mobile robot, which calculates the deviation of the center of gravity of a mounted device and compensates for the deviation of the center of gravity using a stabilizer to stabilize the driving of the mobile robot.

[0017] A control method for driving stabilization of a mobile robot according to an embodiment of the present invention for achieving the above technical task comprises: a mobile robot (10) including a first stabilizer (30) in which a first flywheel (35) rotates at high speed inside a first case (34) and the inclination of the first case (34) is controlled based on a pitch (Y) axis; a second stabilizer (40) in which a second flywheel (45) rotates at high speed inside a second case (44) in an opposite direction to the first flywheel (35) and the inclination of the second case (44) is controlled based on a roll (X) axis; a base frame (14) in which the first and second stabilizers (30, 40) are installed; a body frame (12) in which the base frame (14) is installed; and first to fourth weight sensors (21 to 24) installed in the body frame (12) and measuring the weight of a loaded device (100);

[0018] The center of gravity (COM) coordinates of the above mobile robot (10) are set in advance, and the ZMP coordinates ( ) is calculated, and the first torque ( ) is applied to the first stabilizer (30) so that the ZMP coordinates become closer to the center of gravity (COM) coordinates. ) or generates a second torque ( ) is generated.

[0019] In addition, the control method for driving stabilization of a mobile robot according to an embodiment of the present invention comprises the ZMP coordinates ( ) is the force value (F1 to F4,) measured by the first to fourth weight sensors (21 to 24, i). ) and the position of the first to fourth weight sensors (21 to 24, i) based on the center of gravity (COM) coordinates of the mobile robot (10) ) can be calculated using the mathematical formula below.

[0020]

[0021] In addition, a control method for driving stabilization of a mobile robot according to an embodiment of the present invention comprises the first torque ( ) and the second torque ( ) can be calculated using the mathematical formula below.

[0022]

[0023] In addition, in a control method for driving stabilization of a mobile robot according to an embodiment of the present invention, the first stabilizer (30) may be provided in multiple numbers, and the second stabilizer (40) may be provided in the same number as the first stabilizer (30).

[0024] Specific details of other embodiments are included in the detailed description and drawings.

[0025] A control method for stabilizing the driving of a mobile robot according to an embodiment of the present invention has the effect of stabilizing the driving of the mobile robot by calculating a change in the center of gravity of a mounted device in real time and actively compensating for the change in the center of gravity by controlling a stabilizer.

[0026] FIG. 1 is a drawing for explaining a control method for driving stabilization of a mobile robot according to an embodiment of the present invention.

[0027] Figure 2 is an exemplary drawing for explaining the stabilizer in Figure 1.

[0028] Figure 3 is an exemplary cross-sectional view for explaining the internal configuration of a stabilizer.

[0029] Figure 4 is an example drawing for explaining the moment of inertia.

[0030] FIG. 5 and FIG. 6 are exemplary drawings for explaining the moment of inertia in a control method for driving stabilization of a mobile robot according to an embodiment of the present invention.

[0031] FIG. 7 is an exemplary drawing for explaining the moment of inertia in a control method for driving stabilization of a mobile robot according to another embodiment of the present invention.

[0032] The advantages and features of the present invention and the method for achieving them will become clear with reference to the embodiments described in detail below together with the attached drawings.

[0033] [Explanation of symbols]

[0034] 10: Mobile robot 12: Body frame

[0035] 14: Base plate 16, 18: Wheel

[0036] 21, 22, 23, 24: 1st to 4th weight sensors 30, 40: 1st and 2nd stabilizers

[0037] 31, 41: 1st and 2nd brackets 32, 42: 1st and 2nd tilt motors

[0038] 33, 43: 1st and 2nd shaft brackets 34, 44: 1st and 2nd cases

[0039] 35, 45: 1st and 2nd flywheels 100: Mounting device

[0040] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. The embodiments described below are provided by way of example to help understand the present invention, and it should be understood that the present invention can be implemented with various modifications different from the embodiments described herein. However, when describing the present invention, if it is determined that a detailed description of a related known function or component may unnecessarily obscure the gist of the present invention, the detailed description and specific illustration thereof will be omitted. In addition, the attached drawings are not drawn to scale to help understand the invention, and the sizes of some components may be exaggerated.

[0041] While terms like "first" and "second" may be used to describe various components, these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a first component could be referred to as a "second component," and similarly, a second component could also be referred to as a "first component."

[0042] On the other hand, the terms described below are terms established in consideration of their functions in the present invention, and thus may vary depending on the intention or custom of the manufacturer, and therefore their definitions should be made based on the contents throughout this specification.

[0043] Identical reference numerals throughout the specification refer to identical components.

[0044] First, hardware for driving stabilization of a mobile robot according to an embodiment of the present invention will be described with reference to FIGS. 1 through 3. FIG. 1 is a diagram illustrating a control method for driving stabilization of a mobile robot according to an embodiment of the present invention. FIG. 2 is an exemplary drawing illustrating the stabilizer in FIG. 1. FIG. 3 is an exemplary cross-sectional view illustrating the internal configuration of the stabilizer.

[0045] A mobile robot (10) can be configured to include a body frame (12) that constitutes the skeleton of the mobile robot (10) and wheels (16, 18) for driving.

[0046] A base plate (14) can be fixed to the body frame (12), and a mounting device (100) can be fixed to the upper part of the body frame (12).

[0047] The mounted device (100) may be a quarantine device, a serving device, a security device, a firefighting device, etc., depending on the purpose of use of the mobile robot (10).

[0048] The mounting device (100) can be fixed by providing fixing parts at three or four locations in a form that is mounted on a mobile robot (10), and the embodiment of the present invention describes an example in which fixing parts are provided at four locations.

[0049] The first to fourth weight sensors (21 to 24) can be provided on the upper part of the body frame (12) at a fixed portion, and the first to fourth weight sensors (21 to 24) can measure the weight applied from the mounting device (100).

[0050] The center of gravity of each payload device (100) may vary, and particularly, when an item containing a liquid is loaded, the center of gravity may change in real time depending on the driving speed of the mobile robot (10) and the road surface condition along the moving path. In addition, the center of gravity of the mobile robot (10) may frequently change depending on the driving direction and turning direction of the mobile robot (10). In addition, the center of gravity may change when the mobile robot (10) is stationary and when it is moving.

[0051] That is, the change in the center of gravity means that the posture of the mobile robot (10) becomes unstable, for example, there is a possibility that the mobile robot (10) may tilt or shake, and in this case, the weight values ​​detected by the first to fourth weight sensors (21 to 24) may be different from each other.

[0052] On the other hand, a stabilizer may be configured inside the body frame (12).

[0053] As shown in Fig. 2, the configuration of the stabilizer may include first and second stabilizers (30, 40) arranged on the base plate (14).

[0054] The first stabilizer (30) has a first bracket (31) and a first tilt motor (32) installed on the base plate (14), and a first case (34) is installed on the first bracket (31) and the first tilt motor (32) so as to be rotatable.

[0055] To explain in more detail, the first case (34) may be provided with an external shape in the form of a disk, a first shaft bracket (33) is installed on one side of the first case (34), and the first shaft bracket (33) is installed as a mechanical element such as a bearing on the first bracket (31).

[0056] The above first tilt motor (32) can adjust the tilt angle of the first case (34) according to the first control value of the control unit.

[0057] The first case (34) has a first flywheel (35) installed therein so that it can rotate around the Z axis, and the first flywheel (35) can rotate at high speed by an inner motor.

[0058] The second stabilizer (40) has the same overall configuration as the first stabilizer (30), but the direction in which the yaw (Z) axis of the flywheel is tilted is different.

[0059] To explain in more detail, the first flywheel (35) of the first stabilizer (30) is arranged so that the first case (34) is inclined with respect to the pitch (Y) axis, and the second flywheel (45) rotates at high speed in the opposite direction to the first flywheel (35), and the second case (44) is arranged so that the second case (44) is inclined with respect to the roll (X) axis.

[0060] The second stabilizer (40) is installed with a second bracket (41) and a second tilt motor (42) on the base plate (14), and a second case (44) is installed on the second bracket (41) and the second tilt motor (42) so as to be rotatable.

[0061] The second case (44) may be provided in the form of a disk in its external shape, and a second shaft bracket (43) is installed on one side of the second case (44), and the second shaft bracket (43) is installed as a mechanical element such as a bearing on the second bracket (41).

[0062] The above second tilt motor (42) can adjust the tilt angle of the second case (44) according to the second control value of the control unit.

[0063] The second case (44) has a second flywheel (45) installed therein so that it can rotate around the Z axis, and the second flywheel (45) can rotate at high speed by an inner motor.

[0064] Hereinafter, with reference to FIGS. 4 to 6, a control method for stabilizing the driving of a mobile robot according to an embodiment of the present invention will be described. FIG. 4 is an exemplary drawing for explaining the moment of inertia. FIGS. 5 and 6 are exemplary drawings for explaining the moment of inertia in a control method for stabilizing the driving of a mobile robot according to an embodiment of the present invention.

[0065] When the first and second flywheels (35, 45) rotate at high speed around the yaw (Z) axis, rotational inertia is formed.

[0066] Rotational inertia is the force that tries to maintain the initial posture of the yaw (Z) axis when the first and second flywheels (35, 45) rotate at high speed.

[0067] That is, when the first case (34) tilts while the first flywheel (35) rotates at high speed, a reaction force is generated in the opposite direction to the tilting direction, thereby generating a reaction force to return the first case (34) to its position before tilting.

[0068] The second flywheel (45), like the first flywheel (35), generates rotational inertia while rotating at high speed, and due to this rotational inertia, when the second case (44) is tilted, a reaction force is generated to return it to the position before tilting.

[0069] The moment of inertia is explained with reference to Fig. 4. When a disk with a moment of inertia of I rotates at a constant velocity of ω, the rotational momentum (L) can be calculated as the product of the moment of inertia and the constant velocity. L = Iω. Here, the disk can be understood as the first and second flywheels (35, 45).

[0070] Rotating disk in the Y-axis direction at the speed of When an object rotates by that amount, torque is generated. Torque is the change in rotational momentum with time, which is equal to the torque acting on the object.

[0071] The torque acting on the rotating disk can be calculated using mathematical equation 1.

[0072]

[0073] Here, is the torque, I is the moment of inertia, and ω is the rotational constant velocity.

[0074] In an embodiment of the present invention, the reaction torque (T) in the X-axis direction of the first bracket (31) or the second bracket (41) can be calculated as the product of the moment of inertia (I), the rotational displacement (α), and the rotational speed. am.

[0075] As shown in FIG. 2, an embodiment of the present invention comprises a first stabilizer (30) and a second stabilizer (40), the first stabilizer (30) has a first flywheel (35), and the second stabilizer (40) has a second flywheel (45).

[0076] FIG. 5 is an exemplary drawing for explaining the operating principle in a control method for driving stabilization of a mobile robot according to an embodiment of the present invention, which simplifies the components and shows the rebound torque generated from the flywheel.

[0077] The explanation of each symbol in the mathematical formula described in Fig. 5 is as follows.

[0078] : constant speed Rotational momentum of the first stabilizer (30) rotating

[0079] : Change in rotational motion of the first stabilizer (30)

[0080] : The angle and angular velocity of the first flywheel (35) of the first stabilizer (30) rotated around the pitch (Y) axis

[0081] : First torque generated by the first stabilizer (30)

[0082] : constant speed Rotational momentum of the second stabilizer (40) rotating

[0083] : Change in rotational motion of the second stabilizer (40)

[0084] : The angle and angular velocity of rotation of the second flywheel (45) of the second stabilizer (40) around the roll (X) axis

[0085] : Second torque generated by the second stabilizer (40)

[0086] The first flywheel (35) of the first stabilizer (30) and the second flywheel (45) of the second stabilizer (40) rotate in opposite directions, thereby offsetting the rotational force in the yaw (Z) axis direction.

[0087] The first flywheel (35) of the first stabilizer (30) is rotated about the pitch (Y) axis to incline the first torque () about the roll (X) axis. ) can be generated to offset the rotation in the roll direction.

[0088] The second flywheel (45) of the second stabilizer (40) is rotated by the amount of rotation about the roll (X) axis to apply the second torque () about the pitch (Y) axis. ) can be generated to offset the rotation in the pitch direction.

[0089] A control method for driving stabilization of a mobile robot according to an embodiment of the present invention can determine the operation of the first and second stabilizers using zero moment point (ZMP) coordinates. This is explained with reference to FIG. 6 and mathematical equations 2 and 3.

[0090] The center of gravity (COM) coordinates of the mobile robot (10) based on the design program (CAD) data ) can be acquired.

[0091]

[0092] ZMP coordinates ( ) is the force value (F1~F4,) measured from each weight sensor (21~24, i). ) and the center of gravity (COM) of the mobile robot (10) are the origins of the local coordinate system, and the positions of each weight sensor (21-24,i) are ) is used to calculate. Here, the ZMP coordinates can also be calculated based on the same coordinate system as the center of gravity (COM).

[0093]

[0094] The absolute value is greater than '0' or If the absolute value is greater than '0', it can be understood that the ZMP is moving away from the center of gravity (COM).

[0095] is the first torque generated by the first stabilizer (30).

[0096] is the second torque generated by the second stabilizer (40).

[0097] The torque of the first and second stabilizers (30, 40) generates a torque so that when the ZMP coordinate moves away from the center of gravity (COM) coordinate, the ZMP coordinate moves toward the center of gravity (COM) coordinate.

[0098] As described above, the control method for driving stabilization of a mobile robot according to an embodiment of the present invention calculates a ZMP coordinate based on the weight values ​​applied to the first to fourth weight sensors (21 to 24) from the mounting device (100), generates torque in the first and second stabilizers (30, 40) so that the ZMP coordinate approaches the center of gravity (COM) coordinate of the mobile robot (10), and thereby controls the ZMP coordinate to match or approach the center of gravity (COM) coordinate.

[0099] That is, the control method for driving stabilization of a mobile robot according to an embodiment of the present invention calculates the ZMP coordinates in real time when the mobile robot (10) is driving, and controls the ZMP coordinates to be consistent with or close to the center of gravity (COM) coordinates, thereby eliminating the tilting or instability of the mobile robot (10) and stabilizing the driving.

[0100] On the other hand, the mobile robot (10) according to the embodiment of the present invention may be provided with a plurality of first stabilizers (30), as shown in FIG. 7, and the second stabilizers (40) may be provided in the same number as the first stabilizers (30).

[0101] The first flywheel (35) and the second flywheel (45) can rotate at the same rotational speed in opposite directions.

[0102] FIG. 7 shows an example in which a plurality of first stabilizers (30) including a first flywheel (35) are provided, and an example in which the number of second stabilizers (40) is the same as that of the first stabilizers (30).

[0103] The mobile robot (10) of the control method for driving stabilization of the mobile robot according to the embodiment of the present invention described above can respond to tilting in the roll (X) axis and the pitch (Y) axis, but since the number of stabilizers corresponding to each rotation is single (1), rotation in the yaw (Z) axis can occur while the device is operating.

[0104] For example, in Fig. 5, the first stabilizer (30) operates to produce the first rotational momentum go As the roll (X) axis increases, the rotational momentum about the yaw (Z) axis increases. As the rotation occurs around the yaw (Z) axis, it can become a slightly unstable element in the operation of the mobile robot (10).

[0105] In order to respond to rotation about the yaw (Z) axis, a pair of stabilizers with flywheels rotating in opposite directions are provided to respond to rotation in one direction, thereby enabling stable control of the mobile robot (10) without causing rotation about the yaw (Z) axis.

[0106] As shown in Fig. 7, when four stabilizers are arranged, the flywheels of the third and fourth stabilizers corresponding to the rotation about the roll (X) axis rotate in opposite directions, thereby generating a force to rotate the body frame (12) in the opposite direction, and by changing the rotational momentum of the roll (X) axis, it is possible to offset the change in the rotational momentum of the yaw (Z) axis.

[0107] In this way, the mobile robot (10) can suppress rotational motion in the yaw (Z) axis that may occur minutely when one flywheel rotates at high speed and stabilizes the posture by rotational inertia, thereby more reliably stabilizing the driving posture of the mobile robot (10).

[0108] Although the embodiments of the present invention have been described with reference to the attached drawings, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical idea or essential features thereof.

[0109] Therefore, the embodiments described above should be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the claims described below, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

[0110] A control method according to an embodiment of the present invention can be used to stabilize the driving of a mobile robot.

Claims

1. Mobile robot (10) A first flywheel (35) rotates at high speed inside a first case (34), and a first stabilizer (30) whose inclination is controlled based on the pitch (Y) axis of the first case (34); A second flywheel (45) rotates at high speed in the opposite direction to the first flywheel (35) inside the second case (44), and a second stabilizer (40) whose inclination is controlled based on the roll (X) axis of the second case (44); Base frame (14) on which the first and second stabilizers (30, 40) are installed; A body frame (12) on which the above base frame (14) is installed; and It comprises first to fourth weight sensors (21 to 24) installed on the above body frame (12) and measuring the weight of the mounted device (100); The center of gravity (COM) coordinates of the above mobile robot (10) are set in advance, Based on each weight value measured from the first to fourth weight sensors (21 to 24), the ZMP coordinates ( ) is calculated, The first torque ( ) is applied from the first stabilizer (30) so that the above ZMP coordinates become closer to the above center of gravity (COM) coordinates. ) or generates a second torque ( ) in the second stabilizer (40). ) causing; A control method for driving stabilization of a mobile robot including a 2. In paragraph 1, ZMP coordinates ( ) is the force value (F1 to F4,) measured by the first to fourth weight sensors (21 to 24, i). ) and the position of the first to fourth weight sensors (21 to 24, i) based on the coordinates of the center of gravity (COM) of the mobile robot (10). ) is calculated by the mathematical formula below; A control method for driving stabilization of a mobile robot including a 3. In paragraph 2, The first torque above ( ) and the second torque ( ) is calculated by the mathematical formula below; A control method for driving stabilization of a mobile robot including a 4. In paragraph 1, The above first stabilizer (30) is provided in multiples, The second stabilizer (40) is provided in the same number as the first stabilizer (30); A control method for driving stabilization of a mobile robot including a

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