KR100500831B1 - Method calculating rotated angles of robot cleaner - Google Patents

Abstract

The present invention relates to a method for calculating a rotation angle of a robot cleaner capable of calculating a rotation angle through less image data processing in a robot cleaner for controlling a path using an upward camera. The above object is provided with an upper camera and a driving unit, the rotation angle calculation method of the robot cleaner for controlling the rotation of the robot cleaner by calculating the rotation angle using the upper camera, the upper image captured by the upper camera distance -Converting the angular axis coordinate data to create reference image information; extracting and storing feature points from the reference image information; rotating the robot by a predetermined angle by driving the driving unit; and upward image captured by the upper camera. To convert the data into distance-angle coordinate data to create current image information, extracting feature points from the current image information, and comparing the feature points of the current image information with the feature points of the reference image information. Calculating the distance traveled on the angular axis at, and converting the travel distance into an angle Comprising a step of calculating the angle rotated by the eastern part is achieved by providing a method for calculating the rotation angle of the robot cleaner comprising a.

Description

Method for calculating rotated angles of robot cleaner

The present invention relates to a method for controlling a robot cleaner that runs by recognizing a current position using a camera, and more particularly, to a method of calculating a rotation angle of a robot cleaner using an image captured by an upper camera.

In general, the robot cleaner which recognizes the current position by using the upward camera and calculates the path is calculated by using the upward image captured by the upward camera.

Referring to the conventional method for calculating the rotation angle of the robot cleaner using the upper image as follows.

Before rotation, the upper image captured by the upper camera is divided into pixels and stored in the storage device. Subsequently, the driving unit is controlled to rotate the robot cleaner by a predetermined angle. The upper image is imaged again by the upper camera in a state of being rotated by a predetermined angle. It is determined whether the robot cleaner is rotated by a predetermined angle by comparing the newly captured current upper image with the stored upper image as a whole. At this time, the method for determining whether the robot cleaner has rotated a predetermined angle is to first process the stored upper image by rotating the robot cleaner at a predetermined angle to be rotated and stored as a reference image, and rotate the robot cleaner at a predetermined interval. The image of the upper portion is continuously photographed with the upper camera to compare whether the captured upper image matches the reference image. When the current upper image is compared with the reference image while the robot cleaner is continuously rotated and the current upper image is matched with the reference image, the robot cleaner is rotated at a desired angle, so the rotation is stopped. One example is shown in FIG. Fig. 1 shows an upper image A captured by an upper camera in a stationary state, an image B rotated 90 degrees of the upper image, and an upper image captured while the robot cleaner is rotated 30 degrees, 60 degrees, and 90 degrees. C, D, E) are shown. If the robot cleaner receives a command to rotate 90 °, the robot cleaner first picks up the upper image A when stopped and then makes an image B which rotates the upper image 90 ° and stores it. After that, the robot cleaner controls the driving unit and rotates to capture the upper image with the upper camera at a predetermined interval. The robot cleaner stops rotating when the captured upper image is compared with the stored image by comparing the captured upper image with the stored image. That is, if the captured upper image corresponds to the E image via the C and D images, the robot cleaner stops rotating.

However, rotating the robot cleaner in the above manner results in a high data throughput because all pixels in the two contrasting upper images must be compared. Therefore, the image processing speed becomes very slow, making it difficult to control the robot in real time.

Therefore, in order to control the robot in real time, the invention has been demanded for a method of calculating the rotation angle of the robot cleaner capable of quickly calculating the rotation angle by reducing the image data throughput of the upper image.

The present invention has been made in view of the above problems, to provide a method of calculating the rotation angle of the robot cleaner with a short time to calculate the rotation angle by reducing the throughput of the image data to control the robot cleaner in real time. There is this.

An object of the present invention as described above, in the method of calculating the rotation angle of the robot cleaner having an upper camera and a driving unit, and calculating the rotation angle by using the upper camera to control the rotation of the robot cleaner, the image captured by the upper camera Converting the upper image into distance-angle coordinate data to create reference image information; extracting and storing feature points from the reference image information; rotating the robot by a predetermined angle by driving the driving unit; Converting the captured upper image into distance-angle coordinate data to create current image information; extracting feature points from the current image information; and comparing feature points of the current image information with those of reference image information. Calculating a distance moved on the angle axis in the angle axis coordinates, and converting the movement distance into an angle; The step of calculating the desired angle of rotation by a driving unit; by providing a rotation angle calculating method of a robot cleaner comprising: a is achieved.

Here, the step of converting the upper image into the distance-angle coordinate data to generate the reference image information or the current image information includes: capturing the upper image of the robot cleaner with the upper camera; and image pixels constituting the upper image are orthogonal to each other. Storing coordinate data, converting rectangular coordinate data into polar coordinate data, and converting polar coordinate data into distance-angular axis coordinate data.

Hereinafter, a method of calculating a rotation angle of the robot cleaner according to the present invention will be described in detail with reference to the accompanying drawings.

2 and 3 illustrate an example of a robot cleaner in which a rotation angle calculation method according to the present invention is used.

Referring to the drawings, the robot cleaner 10 includes a main body 11, a sensor unit 12, a suction unit 16, a driving unit 20, an upper camera 30, a front camera 32, a control unit 40, A storage device 41 and a transmitter / receiver 43. Reference numeral 50 is a rechargeable battery.

The sensor unit 12 may measure a travel distance and an obstacle detection sensor 14 disposed at predetermined intervals around the side surface of the main body 11 so as to transmit a signal to the outside and receive the reflected signal. The traveling distance detection sensor 13 is provided.

The obstacle detecting sensor 14 is arranged along the outer circumferential surface of the infrared light emitting element 14a for emitting infrared light and the light receiving element 14b for receiving the reflected light in a vertical pair. Alternatively, the obstacle detection sensor 14 may emit an ultrasonic wave, and an ultrasonic sensor capable of receiving the reflected ultrasonic wave may be applied. The obstacle detecting sensor 14 is also used to measure the distance from the obstacle or the wall.

The mileage detection sensor 13 may be a rotation detection sensor for detecting the rotation speed of the wheel (21a, 21b, 22a, 22b). For example, the rotation detection sensor may be an encoder provided to detect the rotation speed of the motor (23, 24).

The suction part 16 is provided on the main body 11 so that the dust | floor of the floor which opposes while collecting air may be collected. Such a suction unit 16 can be configured by a variety of known methods. As an example, the suction unit 16 includes a suction motor (not shown) and a dust collecting chamber for collecting dust sucked through a suction port or a suction pipe formed to face the floor by driving the suction motor.

The drive unit 20 is a motor that rotates two wheels 21a and 21b installed on both sides of the front, two wheels 22a and 22b installed on both sides of the rear and two wheels 22a and 22b at the rear, respectively. And a timing belt 25 installed to transmit the power of the 23 and 24 and the rear wheels 22a and 22b to the front wheels 21a and 21b. The driver 20 independently drives the motors 23 and 24 to rotate in the forward or reverse directions according to the control signal of the controller 40. The running direction is determined by controlling the rotation speed of each motor 23, 24 differently.

The front camera 32 is installed on the main body 11 so as to capture the front image and outputs the captured image to the controller 40.

The upper camera 30 is installed on the main body 11 so as to capture the image of the upper side and outputs the captured image to the control unit 40. Preferably, a fisheye lens (not shown) is applied to the upper camera 30.

The controller 40 processes the signal received through the transmitter / receiver 43 and controls each element. The control unit 40 is the position information of a specific object such as a fluorescent lamp or a fire alarm existing in the upper image captured by the upper camera 30, or the position of the recognition mark installed on the ceiling of the work area for use for position recognition. Use the information to recognize your current location. Basic image information about the comparison object or the recognition mark for allowing the control unit 40 to find the object or the mark for recognition in the image photographed by the upper camera 30 is stored in the storage device 41. . The controller 40 calculates a driving route for performing a desired task using the recognized position information and controls each element so that the robot cleaner 10 runs along the driving route. In addition, the control unit 40 controls the driving unit 20 so that the robot cleaner 10 turns a predetermined angle in the order described later. When a key input device (not shown) provided with a plurality of keys for manipulating the function setting of the device is further provided on the main body 11, the controller 40 processes the key signal input from the key input device.

The storage device 41 stores the upper image captured by the upper camera 30, and then assists the controller 40 to calculate the position information or the driving information.

The transmitter / receiver 43 transmits data to be transmitted to the external device 60 through the antenna 42, and transmits a signal received through the antenna 42 to the controller 40.

The external device 60 controls the operation or operation of the robot cleaner 10 from the outside, and a remote control device composed of a remote controller or a computer is used.

A method of controlling the rotation angle of the robot cleaner 10 by the controller 40 in the robot cleaner having the above configuration will be described with reference to FIGS. 4 and 5 as follows.

First, when the controller 40 receives the rotation command or determines that the obstacle needs to be rotated by an obstacle in front of the driving path, the controller 40 uses the upper image captured by the upper camera 30 as a reference. Generate image information (S110).

The method of generating reference image information will be described in more detail as follows. When the main body 11 needs to be rotated, the control unit 40 generates an upper image by capturing the ceiling using the upper camera 30 at the current position (S111). The upper image is divided into a plurality of pixels, and the position of each pixel is stored in the storage device 41 as rectangular coordinate data (S112). At this time, the rectangular coordinate data calculates the position coordinates of each pixel using the center O of the upper image 71 as the coordinate origin as shown in FIG. 6. Subsequently, an angle formed by the horizontal axis (X axis) of the line segment connecting the rectangular coordinate data (x, y) of the pixel to an arbitrary pixel at the origin O and an arbitrary pixel at the origin O The polar coordinate data is converted into polar coordinate data expressed by?) (S113). In this case, a formula for converting rectangular coordinate data into polar coordinate data is represented by Equation 1 below, and the geometric correlation is shown in FIG. 6.

Here, x and y represent coordinate values of the x-axis and y-axis of an arbitrary pixel A in the coordinate system whose origin O is the center O of the upper image 71, and ρ represents the pixel A from the coordinate origin O in the coordinate system. Represents the distance to, and θ represents the angle formed by the straight line connecting the pixel A at the coordinate origin O with the X axis.

Subsequently, polar coordinates (ρ, θ) of all the pixels in the upper image calculated by Equation 1 are converted into distance-angle axis coordinate data (S114). This transformation arranges each pixel in a distance-angle axis coordinate system where the vertical axis represents the distance ρ to the pixel and the horizontal axis represents the angle axis representing the angle θ that each pixel makes with the X axis.

Next, the control unit 40 extracts the feature point from the distance-angle axis coordinate system and stores it in the storage device 41 (S120). As the image processing method of extracting feature points from a distance-angle axis coordinate system, various known methods may be applied. For example, a method of converting to a gray level for an image converted into a distance-angle coordinate system and then finding pixel points distinguished from surrounding values may be applied.

When the extraction and storage of the feature point at the current position is completed, the controller 40 controls the driving unit 20 to rotate a predetermined angle (S130). In this case, in the case of the robot cleaner 10 according to the present embodiment, the robot cleaner 10 may be rotated in the left and right directions by varying the rotation speed of the left and right motors 23 and 24.

When the robot cleaner 10 rotates by a predetermined angle, the control unit 40 again photographs the upper image using the upper camera 30. The current image information is generated by converting the newly captured upper image (S140). At this time, the method of generating the current image information is the same as the process of generating the reference image information described above. In other words, each pixel of the upper image is converted into rectangular coordinate data, the rectangular coordinate data is converted into polar coordinate data, and the polar coordinate data is converted into distance-angle axis coordinates.

When generation of the current image information is completed, the controller 40 detects the position of the same feature point as the feature point extracted from the reference image information from the current image information (S150). At this time, since the upper image is the image of the ceiling of the same position after the robot cleaner 10 rotates a predetermined angle at the same position, as shown in Figure 7, the position coordinates of the feature point (P ') in the current image information The positional coordinates and the distance coordinates of the feature point P in the reference image information are the same as p, and only the angular coordinates change from θ to θ '. That is, in the distance-angle axis coordinate system, the distance coordinates ρ of the feature points do not change, and only the angle coordinates θ change according to the rotation angle of the robot cleaner 10. Therefore, the controller 40 may detect the same feature point P ′ as the reference image information from the current image information based on the distance coordinate of the feature point P extracted from the reference image information as a reference axis. An example of this is shown in FIG. 8. Referring to the drawings, the upper image 74 when the feature points P1 and P2 of the image information 73 obtained by converting the upper image 72 before rotation to the distance-angle axis coordinate system is rotated 90 degrees to the distance-angle axis coordinate system. In the converted image information 75, it can be seen that P1 'and P2' are moved to the left along the angle axis. Since the detection of this feature point is not performed for the entire upper image but only for the distance coordinate based on one distance coordinate, the amount of data processed by the control unit 40 performs image processing on the entire upper image. It is greatly reduced compared to the quantity. Therefore, the time for the controller 40 to process the image to calculate the rotation angle is shortened.

Next, the controller 40 compares the angular coordinate value of the feature point in the reference image information with the angular coordinate value of the feature point in the current image information to calculate the movement amount of the feature point (S160).

Subsequently, the control unit 40 converts the movement amount of the feature point into an angle value to calculate the angle at which the robot cleaner 10 rotates. The controller 40 compares the calculated angle with the target rotation angle of the robot cleaner 10 and determines whether to continue to rotate.

As described above, according to the method of calculating the rotation angle of the robot cleaner according to the present invention, in order to calculate the rotation angle, the controller does not need to process the entire upper image, but only a part of the image processing. This reduces the image processing time. Therefore, the controller may rotate while controlling the robot cleaner in real time.

As described above, according to the method of calculating the rotation angle of the robot cleaner according to the present invention, since the robot cleaner only needs to process the image of a part of the upper image, the processing amount of the image data is reduced, thereby reducing the time for calculating the rotation angle. have. Therefore, it is possible to control the rotation of the robot cleaner in real time.

The present invention is not limited to the above-described specific embodiments, and various modifications can be made by those skilled in the art without departing from the gist of the invention as claimed in the claims. Such changes are intended to fall within the scope of the claims.

1 is a view showing a state of change of the upper image when the robot cleaner rotates by a predetermined angle by a method of calculating a rotation angle of a conventional robot cleaner;

Figure 2 is a perspective view showing a state in which the cover of the robot cleaner used to calculate the rotation angle of the robot cleaner according to the present invention removed;

3 is a block diagram of the robot cleaner of FIG.

4 is a flow chart illustrating a method of calculating a rotation angle of the robot cleaner according to the present invention;

5 is a flowchart illustrating a method of generating reference image information or current image information of FIG. 4;

6 is a view showing the relationship between the Cartesian coordinates and the polar coordinates used in the rotation angle calculation method of the robot cleaner according to the present invention;

7 is a view illustrating a state in which a position of an arbitrary pixel is changed in the upper image captured by the upper camera while the robot cleaner of FIG. 2 rotates.

8 is a view showing an example in which the feature point is changed in the distance-angle axis coordinates in the method for calculating the rotation angle of the robot cleaner according to the present invention.

* Description of the symbols for the main parts of the drawings *

10; Robot cleaner 11; main body

12; Sensor unit 20; Driving part

30; Upper camera 32; Front camera

40; Control unit 41; Memory

50; Rechargeable battery 60; External device

71,72,74; Upper image 73,75; Distance-angle coordinate image

Claims (2)

In the method of calculating the rotation angle of the robot cleaner having an upper camera and a drive unit, and controlling the rotation of the robot cleaner by calculating the rotation angle using the upper camera, Generating reference image information by converting coordinates of a plurality of pixels constituting the upper image captured by the upper camera into distance-angle axis coordinate data; Extracting feature points from the reference image information and storing the coordinates; Rotating the robot by a predetermined angle by driving the robot cleaner; Generating current image information by converting coordinates of a plurality of pixels constituting the upper image captured by the upper camera into distance-angle axis coordinate data; Fixing the distance axis from the current image information to the distance coordinates of the feature points of the reference image information and extracting feature points corresponding to the feature points of the reference image information along the angle axis; Comparing the coordinates of the feature point of the current image information with the coordinates of the feature point of the reference image information to calculate a distance moved by the feature point on the angular axis in a distance-angle axis coordinate; And And calculating the angle rotated by the driving unit by the robot cleaner by converting the moving distance into an angle. The method of claim 1, wherein the generating of the reference image information or the current image information by converting the upper image into distance-angle axis coordinate data comprises: Imaging an upward image of the robot cleaner with the upward camera; Storing positions of a plurality of image pixels constituting the upper image as rectangular coordinate data, respectively; Converting the rectangular coordinate data into polar coordinate data; And And converting the polar coordinate data into distance-angle axis coordinate data.