Control method for driving a robot

Abstract

A driving control method for a robot according to an embodiment of the present invention comprises: a step of recognizing the generation of a sound source through a microphone; a step of analyzing the generated sound source to extract a sound source generator and calculating the location of the sound source; a step of driving in a Voronoi search mode based on the calculated location information of the sound source; a step of switching the driving mode to a direct search mode when a mode switching condition is satisfied during the process of driving in the Voronoi search mode; a step of determining whether the vicinity of the sound source has been reached during the process of driving in the direct search mode; and a step of identifying a sound source generator when it is determined that the vicinity of the sound source has been reached.

Description

Technology Field

[0001] The present invention relates to a driving control method for a robot that enables the robot to recognize the source of a sound source and drive quickly and accurately to the source of the sound source. Background Technology

[0002] Robots are performing various tasks in place of humans across multiple industries. In particular, robotic vacuum cleaners that move around indoors and clean floors are being used in general households.

[0003] Mobile or driving robots, such as robotic vacuum cleaners, are required not only to accurately recognize their current location and the location of the target point to move to a specific location, but also to have the ability to quickly determine the shortest distance to the target point while minimizing the possibility of colliding with obstacles during travel.

[0004] In particular, when a specific type of sound is output from a sound source located at a point spaced upward from the floor of the space where the robot is situated, the ability to identify the location of the sound source and move is sometimes required.

[0005] For example, when a user cannot remember where they put their mobile phone, if the phone emits a signal, the robot can identify the location of the signal and move quickly to where the phone is located.

[0006] In this case, various methods can be used to locate the sound source; for example, a method utilizing the time difference in sound arrival at multiple acoustic sensors installed on the robot—that is, the Time Difference of Arrival between sensors—can be used to locate the sound source. When using this method, the GCC algorithm is an example of a technique for locating the sound source.

[0007] According to the method for finding the location of a sound source of a robot disclosed in the prior art below, while it has the advantage of being very easy to determine the exact location of the sound source, there is no specific mention of how the robot moves to the location of the sound source.

[0008] For example, when a robot travels in a straight line toward a sound source, it may take a considerable amount of time to reach the source if it encounters an obstacle, and it has the disadvantage of being vulnerable to multi-paths. Prior art literature

[0009] Korean Registered Patent No. 1483269 (2015.01.09) The problem to be solved

[0010] The present invention is proposed to improve upon the problems mentioned above. means of solving the problem

[0011] A driving control method for a robot according to an embodiment of the present invention for achieving the above-mentioned purpose comprises: a step of recognizing the generation of a sound source through a microphone mounted on the robot; a step of analyzing the generated sound source to extract a sound source generator and calculating the elevation angle and azimuth angle formed between the robot and the sound source to calculate the location of the sound source; a step of driving the robot in a Voronoi search mode based on the calculated location information of the sound source; a step of switching the driving mode to a direct search mode when a mode switching condition is satisfied during the process of driving the robot in the Voronoi search mode; and a step of determining whether the elevation angle and the azimuth angle satisfy a set value or fall within a set range during the process of driving the robot in the direct search mode, and determining whether the robot has reached the vicinity of the sound source. The method includes a step of verifying a sound source generator when it is determined that the robot has reached the vicinity of a sound source, and is characterized by determining that the mode switching condition is satisfied if at least one of the following is satisfied: i) when both the currently calculated elevation angle and the elevation angle in the previous cycle are acute angles, or when the current elevation angle is smaller than the elevation angle in the previous cycle; ii) when the elevation angle in the previous cycle was acute but the current elevation angle is obtuse, greater than 90 degrees; or iii) when the current azimuth angle is greater than the azimuth angle in the previous cycle.

[0012] In the above Voronoi search mode, the robot is characterized by moving along a Voronoi path formed on a Voronoi map.

[0013] delete

[0014] In the above Voronoi search mode, the control unit of the robot is characterized by causing the robot to move to the Voronoi path or node closest to the robot.

[0015] In the above direct search mode, the control unit of the robot is characterized by enabling the robot to drive autonomously in a direction in which the elevation angle increases up to a maximum of 90 degrees while maintaining an acute angle, and in a direction in which the azimuth angle decreases down to a minimum of 0 degrees.

[0016] delete

[0017] In order to identify a sound source generator, the control unit of the robot is characterized by operating a camera installed on the robot to acquire a front image (or image) and an upward image (or image) of the robot.

[0018] When it is determined that the captured video (or image) matches the sound source generator, the control unit of the robot is characterized by outputting a message indicating that it has reached the sound source generator.

[0019] The above message includes at least one of a voice signal, a text signal, and a light signal.

[0020] If it is determined that there is a discrepancy between the captured video (or image) and the sound source generator, the control unit of the robot is characterized by causing the robot to return to its original position.

[0021] The above sound source may include the sound of a hair dryer, a vacuum cleaner, an alarm clock, and a washing machine. Effects of the invention

[0022] According to the driving control method of a robot according to an embodiment of the present invention having the above configuration, the following effects are achieved.

[0023] First, since the robot follows a Voronoi path when driving toward a sound source in an indoor space, it has the effect of preventing the robot from colliding with obstacles during driving.

[0024] Second, once the robot has moved to a position close to the sound source, it switches to direct search mode to move to the point closest to the sound source, which has the effect of allowing it to move as close as possible to the location of the sound source. Brief explanation of the drawing

[0025] Figure 1 is a graph showing the coordinates between a sound source and a robot tracking the sound source. Figure 2 is a Voronoi map showing a Voronoi path on an indoor map where the robot is located. FIG. 3 is a flowchart illustrating a driving control method for a robot according to an embodiment of the present invention. Specific details for implementing the invention

[0026] Hereinafter, a driving control method for a robot according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0027] Figure 1 is a graph showing the coordinates between a sound source and a robot tracking the sound source.

[0028] Referring to FIG. 1, a microphone array (m) installed on a robot (O) i ,m j By calculating the time difference of sound waves reaching ), the location of the sound source (X) can be estimated.

[0029] A robot to which the driving control method according to an embodiment of the present invention is applied may have a plurality of microphones arranged, and may have a plurality of microphones arranged in both the horizontal and vertical directions. The robot may have at least three microphones arranged, specifically, two microphones may be arranged in the horizontal direction and one or more microphones may be arranged in the vertical direction. That is, the line connecting the microphones arranged in the horizontal direction and the line connecting the microphones arranged in the vertical direction may intersect in a cross shape.

[0030] In detail, the position of the sound source (X) can be expressed as the elevation angle (θ) and azimuth angle (φ) formed between the center of the microphone array of the robot (O) and the sound source.

[0031] The time delay can be calculated by calculating the cross-correlation function between two microphones installed on the robot (O) under free sound field conditions. That is, for plane wave incidence, the difference in arrival time (τ) between the two microphones ij ) can be expressed by the following formula.

[0032]

[0033] c : speed of sound,

[0034] Direction vector from the center of the microphone array to the sound source

[0035] d: Position vector of microphone mi and mj

[0036] To perform sound source location estimation, based on multiple time delay values ​​calculated from the microphone array Calculate , and the corresponding x, y, z components (u x ,u y ,u z Through ), the azimuth (φ) of the sound source and the elevation angle (θ) can finally be calculated.

[0037] The azimuth and elevation angles of the sound source estimated through the calculation of the Time Difference of Arrival can be expressed as follows.

[0038]

[0039]

[0040] The method of estimating the location of a sound source using the aforementioned arrival delay time is defined as the Interaural Time Difference (ITD). Since this method of sound source location estimation is a widely known calculation technique, further explanation regarding it is omitted.

[0041] Meanwhile, the driving control method of a robot according to an embodiment of the present invention is characterized in that a Voronoi-based sound search mode is applied in a certain section so that the robot moves toward the location of a sound source along a Voronoi map, and from a certain point in time, the Voronoi-based sound search is excluded and a direct sound search mode is applied.

[0042] Voronoi-based sound source search has the advantage of enabling more accurate search driving by compensating for its vulnerability to the multipath effect. The multipath effect can be understood as the phenomenon that causes search delays when there are multiple paths to search a sound source, as it is difficult to quickly determine which path is advantageous to choose.

[0043] Figure 2 shows a Voronoi map with a Voronoi path displayed on an indoor map where the robot is located.

[0044] Path planning is the process by which an autonomous mobile robot finds a fast and safe path to a target point while avoiding obstacles and workers within the workspace. Voronoi graphs, a type of graph map, are widely used as a method for traversing the paths of autonomous mobile robots.

[0045] A Voronoi graph creates a loop that encircles the obstacles and generates a map consisting of a path formed by lines connecting this loop to the starting point and the target point. The path found by this method maintains an even distance between obstacles, which has the advantage of generating a safe path with a low risk of collision.

[0046] Referring to FIG. 2, the indoor map (10), which is the map of the indoor space where the robot is located, may be provided from the outside to the robot's control unit and stored, or the robot may generate the indoor map (10) while moving directly and simultaneously generate a Voronoi map by adding a Voronoi path (11) based thereon. A Voronoi path (11) is also called an edge and can be understood as a line connecting points that maintain equal spacing from two adjacent obstacles, and a point where two Voronoi paths (11) with different extension directions meet can be defined as a node (12).

[0047] Since the method for generating Voronoi maps and other details are already widely known, further explanation regarding them will be omitted.

[0048] Hereinafter, a driving control method for a robot according to an embodiment of the present invention will be described in detail with reference to a flowchart.

[0049] FIG. 3 is a flowchart illustrating a driving control method for a robot according to an embodiment of the present invention.

[0050] Referring to FIG. 3, when a sound source is generated in the indoor space where the robot is located, the robot recognizes the generation of the sound source (S11).

[0051] And, when the robot recognizes the generation of a sound source, the control unit of the robot performs the task of analyzing what the source that generated the sound source is, that is, the task of extracting the sound source (S12).

[0052] Here, the sound source generator includes various sound sources that may occur in the space where the robot is deployed, and for example, sound sources generated within a home may include the sound of a hair dryer, a vacuum cleaner, an alarm clock, a washing machine, etc.

[0053] Once it is confirmed what the entity generating the sound source is, the control unit of the robot calculates the location of the sound source using the sound source location estimation method described in Fig. 1 (S13). Accordingly, the location of the sound source can be expressed in terms of an azimuth and an elevation angle.

[0054] Then, when the location of the sound source is calculated by the control unit of the robot, an indoor map is loaded (S14) and a Voronoi map is generated (S15). However, the step of loading the indoor map and generating the Voronoi map may be omitted. In other words, when the robot is deployed indoors, the Voronoi map may already be stored in the robot's memory.

[0055] Meanwhile, the robot calculates the location of the sound source and then starts driving in a Voronoi-based search mode (or Voronoi search mode) (S16).

[0056] In Voronoi search mode, the control unit of the robot first causes the robot to move to the Voronoi path (11) or node (12) closest to the robot.

[0057] Then, the robot is made to move in a direction closer to the sound source along the Voronoi path (11) closest to the robot. If the robot is located at a node (12) where multiple Voronoi paths (11) diverge, rather than at the Voronoi path (11), the Voronoi path (11) with the smallest angle between the path extension direction and the direction of the sound source can be selected as the driving direction in order to find the optimal path for sound source search.

[0058] As described above, while the robot travels along a predetermined Voronoi path, the robot periodically determines whether the mode switching condition is satisfied (S17).

[0059] The conditions for switching modes are as follows.

[0060] i) If both the currently calculated elevation angle and the elevation angle in the previous period are acute, the current elevation angle is smaller than the elevation angle in the previous period, or

[0061] ii) If the elevation angle in the previous period was acute but the current elevation angle is obtuse, which is greater than 90 degrees, or

[0062] iii) When the current azimuth is greater than the azimuth in the previous cycle

[0063] If at least one of the three conditions above is satisfied, it means that the robot is moving away from the sound source or is passing the sound source.

[0064] Accordingly, when a situation arises in which at least one of the three conditions above is satisfied, the robot switches from Voronoi search mode to direct sound source search mode (or direct search mode) and drives (S18).

[0065] In direct search mode, the robot does not drive along the Voronoi path but drives toward the sound source based on the calculated elevation angle and azimuth angle. In other words, the robot is made to drive autonomously in a direction where the elevation angle increases up to a maximum of 90 degrees while maintaining an acute angle, and in a direction where the azimuth angle decreases down to a minimum of 0 degrees.

[0066] Then, when it is determined that the robot has reached the vicinity of the sound source while driving in direct search mode (S19), the control unit of the robot activates the camera installed on the robot to capture a video or image of the front and / or upper side of the robot. Then, the captured video is analyzed to determine whether the sound source generator extracted in step S12 appears in the captured video or image (S21).

[0067] When the captured image and the sound source generator match (S22), the control unit may output a notification message (S23). Here, the notification message includes various forms of messages, including voice signals, text signals, and light signals, indicating that the sound source generator has been found.

[0068] If it is determined that the captured image and the sound source generator are inconsistent, the robot may be made to return to its original position (S24).

[0069] Meanwhile, the condition for determining that the robot has reached the vicinity of the sound source is whether the elevation angle and azimuth angle satisfy the set values ​​or fall within the set range.

[0070] For example, if the robot is located directly below the sound source, the elevation angle may be 90 degrees, and if the robot is located directly in front of the sound source, both the elevation angle and the azimuth angle may be 0 degrees. If the height of the robot and the sound source are the same, both the elevation angle and the azimuth angle may satisfy 0 degrees, and at the same time, the distance between the robot and the sound source may be within a set distance, satisfying the obstacle encounter condition.

[0071] In addition, the conditions for determining that the robot has reached the vicinity of a sound source can be set in various ways.

[0072] According to the driving control method of a robot according to an embodiment of the present invention as described above, the robot is driven in Voronoi search mode initially, and then driven in direct search mode when the robot is somewhat close to a sound source generator. This minimizes the possibility of encountering an obstacle while driving and also minimizes the possibility of the robot passing by a sound source generator, thereby enabling the robot to reach the sound source generator in the shortest possible time.

Claims

Claim 1 A step of recognizing the generation of a sound source through a microphone mounted on a robot; a step of analyzing the generated sound source to extract the sound source source, and calculating the elevation angle and azimuth angle formed between the robot and the sound source to calculate the location of the sound source; a step of driving the robot in Voronoi search mode based on the calculated location information of the sound source; a step of switching the driving mode to Direct Search mode if a mode switching condition is satisfied while the robot is driving in Voronoi search mode; a step of determining whether the elevation angle and the azimuth angle satisfy a set value or fall within a set range while the robot is driving in Direct Search mode, and determining whether the robot has reached the vicinity of the sound source. A driving control method for a robot, characterized by including a step of verifying a sound source generator when it is determined that the robot has reached the vicinity of a sound source, and determining that the mode switching condition is satisfied if at least one of the following is satisfied: i) when both the currently calculated elevation angle and the elevation angle in the previous cycle are acute angles, or when the current elevation angle is smaller than the elevation angle in the previous cycle; ii) when the elevation angle in the previous cycle was acute but the current elevation angle is obtuse, greater than 90 degrees; or iii) when the current azimuth angle is greater than the azimuth angle in the previous cycle. Claim 2 delete Claim 3 A driving control method for a robot according to claim 1, characterized in that, in the Voronoi search mode, the robot moves along a Voronoi path formed on a Voronoi map. Claim 4 A driving control method for a robot according to claim 3, wherein, in the Voronoi search mode, the control unit of the robot causes the robot to move to the Voronoi path or node closest to the robot. Claim 5 delete Claim 6 A driving control method for a robot according to claim 4, wherein in the direct search mode, the control unit of the robot enables the robot to drive autonomously in a direction in which the elevation angle increases up to a maximum of 90 degrees while maintaining an acute angle, and in a direction in which the azimuth angle decreases down to a minimum of 0 degrees. Claim 7 A driving control method for a robot according to claim 6, characterized in that, in order to identify a sound source generator, the control unit of the robot operates a camera installed on the robot to acquire a front image (or image) and an upward image (or image) of the robot. Claim 8 A driving control method for a robot according to claim 7, characterized in that when it is determined that the captured video (or image) and the sound source generator match, the control unit of the robot outputs a message indicating that it has reached the sound source generator. Claim 9 In claim 8, the above message is a driving control method for a robot comprising at least one of a voice signal, a text signal, and a light signal. Claim 10 A driving control method for a robot according to claim 7, characterized in that if it is determined that the captured video (or image) and the sound source generator are inconsistent, the control unit of the robot causes the robot to return to its original position. Claim 11 In claim 1, the sound source is a driving control method for a robot including a hair dryer sound, a vacuum cleaner sound, an alarm clock sound, and a washing machine sound.

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