KR101066037B1 - Left/right wheel size error compensation apparatus and method for mobile robot - Google Patents

Abstract

The present invention relates to a left and right wheel size error correction device and method of a mobile robot, the difference between the distance between the target and the target in the initial state and the distance between the target, the image of the initial state and the image after a certain distance movement By comparing the calculated number of pixels by moving the robot using the distorted number of pixels in the image, and using the distance compensation value according to the distorted distance, the rotational speed of the left and right wheels is changed relatively, This is to prevent the movement error due to the size difference. To this end, the present invention provides an image capturing means for photographing an image of a target; Image processing means for processing an image captured by the image capturing means and calculating a distance from the image capturing means to the target based on the predetermined processed image; In the initial state, the first image output from the image processing means and the first distance from the image capturing means to the target, the second image output from the image processing means after a predetermined distance and the image capturing means; Drive to control the driving speed of the left wheel and the right wheel based on the calculated distance correction value by calculating the distance to be shifted during the movement based on the second distance to the target, the distance correction value according to the distance during the movement Control means for outputting a control signal; And driving means for driving the left wheel and the right wheel by the drive control signal.

Description

LEFT / RIGHT WHEEL SIZE ERROR COMPENSATION APPARATUS AND METHOD FOR MOBILE ROBOT}

1 is a schematic view showing a general mobile robot.

Figure 2 is an exemplary view showing the tracking of a typical mobile robot target.

Figure 3 is a block diagram showing a schematic configuration of a general mobile robot.

Figure 4 is a block diagram showing a schematic configuration for the left / right wheel size error correction device of the present invention mobile robot.

5 is a flow chart for the left / right wheel size error correction method of the present invention mobile robot.

Figure 6 is a schematic diagram showing the actual mobile robot tilted to move.

Figure 7 shows a camera image of the embodiment for the case where the actual mobile robot is tilted to move.

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

10: video recording means 20: video processing means

30: control means 40: driving means

50: left wheel 60: right wheel

The present invention relates to an apparatus and method for correcting left / right wheel size errors of a mobile robot, and in particular, a movement for preventing an error due to the movement of the robot by correcting a distorted distance when the robot is moved by the size difference between the left and right wheels. The present invention relates to a left and right wheel size error correction device and method of a robot.

In general, unlike industrial robots that perform tasks only for the purpose of a user, the entertainment robot family has artificial intelligence and can be autonomous like a living thing.

The industrial robot performs work while repeatedly moving along the taught path, and requires the precision of the position, whereas the entertainment robot requires the smooth movement of the position.

The above-mentioned entertainment group robots perform predetermined tasks while pre-set driving in accordance with a built-in program. In order to automatically drive the preset driving route, a large number of robots for detecting the position, mileage, and obstacles of the robot are used. Sensors are used.

Such a robot is equipped with wheels on the robot body as shown in FIG. 1 so as to autonomously move space, and also attach a camera to avoid obstacles or to chase a specific target.

The image captured by the camera has a function of tracking a target such as a ball of a specific color or a human face through vision processing, so that the user can guide the robot in a desired direction.

In addition, the robot may include a gyro sensor for detecting an accurate change of direction of the robot, an encoder for determining the driving distance by detecting the number of revolutions of the wheel, and an ultrasonic sensor for detecting a distance and an obstacle with a target. Sensors are attached to the robot.

FIG. 2 is an exemplary view showing a general mobile robot tracking a target, and FIG. 3 is a block diagram showing a schematic configuration of a general mobile robot. As shown in FIG. An obstacle detecting unit 1 detecting an obstacle by the collision; A controller (2) for outputting a control signal for switching the running of the robot in order to avoid the obstacle by the signal output from the obstacle detecting unit (1); A left wheel motor driving unit 3 for driving the left wheel motor 5 at a constant speed by a control signal of the control unit 2; By the control signal of the said control part 2, the right wheel motor drive part 4 which drives the right wheel motor 6 at a constant speed is comprised.

First, when the driving command is generated by the user, the control unit 2 outputs a control signal for matching the driving speed of the left wheel motor 5 and the right wheel motor 6 to advance the robot.

Accordingly, the left wheel motor driver 3 drives the left wheel motor 5 by the control signal of the controller 2, and the right wheel motor driver 4 is driven by the control signal of the controller 2. 6).

As a result, the robot moves forward.                         

At this time, the obstacle detecting unit 1 detects a distance to an external obstacle, and if the obstacle is detected as a result of the detection, the obstacle detecting unit 1 applies the obstacle detecting signal accordingly to the controller 2.

Accordingly, the control unit 2 stops driving by the obstacle detection signal and outputs a control signal for avoiding the obstacle, wherein the control unit 2 rotates the robot cleaner according to the rotational direction of the left wheel motor ( 5) and a control signal for varying the speed of the right wheel motor 6 to the left wheel motor driver 3 and the right wheel motor driver 4.

Accordingly, the left wheel motor driver 3 drives the left wheel motor 5 by the control signal of the controller 2, and the right wheel motor driver 4 is the right wheel motor by the control signal of the controller 2. (6) is driven to rotate the robot at any random angle.

At this time, the controller 2 controls the two wheels independently to move the robot, in this case, the size of the left wheel and the right wheel does not completely match, and each tire due to the independent use of the left and right wheels Due to the non-uniform wear of the mobile robot does not go straight, there is a problem to move inclined in the left or right direction.

The present invention has been made to solve the above problems, and compares the difference value between the distance from the target in the initial state and the target after the movement, the image of the initial state and the image after a certain distance movement, the image Calculate the distorted distance by moving the robot using the distorted number of pixels and relatively change the rotational speeds of the left and right wheels by using the distance correction value according to the distorted distance. It is an object of the present invention to provide an apparatus and method for correcting left / right wheel size errors of a mobile robot to prevent movement errors.

The present invention for achieving the above object, the image taking means for shooting an image of the target;

Image processing means for processing an image captured by the image capturing means and calculating a distance from the image capturing means to a target using the image;

In the initial state, the image is shifted by using the distance output from the image processing means and the image capturing means to the target, and the distance from the image output means and the image capturing means to the target output after a predetermined distance. Calculate the distance,

Control means for calculating a distance correction value according to the distorted distance during the movement and outputting a drive control signal for controlling the drive speeds of the left and right wheels according to the distance correction value;

By the drive control signal, it characterized in that it comprises a drive means for driving the left wheel and the right wheel at different speeds.

The present invention for achieving the above object,

Calculating a distance between the image capturing means and the target object in an initial state by using the target image input from the image capturing means when the driving mode is selected by the user;                     

Moving the mobile robot for a predetermined time;

Comparing the image of the initial state of the robot with the image after the movement and calculating a distance which is displaced when the robot moves due to the size difference of the left / right wheels of the robot based on the comparison result;

 The distance correction value is calculated according to the distorted distance when the robot moves, and according to the distance correction value, a process of controlling the rotational speed of the left / right wheels is relatively performed.

Hereinafter, the operation and effects of the left and right wheel size error correction device and method of the mobile robot according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 4 is a block diagram showing the configuration of the left / right wheel size error correction device of the present invention mobile robot.

As shown in Fig. 4, the present invention includes an image capturing means 10 for capturing an image of a target; Image processing means (20) for predetermined processing of the image captured by the image capturing means (10) and calculating a distance from the image capturing means (10) to a target using the image; In the initial state, the image and the image capturing means 10 output from the image processing means 20 after moving the distance and the predetermined distance from the image and the image capturing means 10 to the target output from the image processing means 20 Calculate the distorted distance at the time of movement using the distance to the target, calculate the distance correction value according to the distorted distance at the time of movement, and calculate the driving speed of the left wheel 50 and the right wheel 60 according to the distance correction value. Control means (30) for outputting a drive control signal for controlling; In response to the drive control signal, a drive means 50 for driving the left wheel 50 and the right wheel 60 at different speeds is provided.

The control means 30 obtains the difference between the distance from the image capturing means 10 to the target after the movement of the predetermined distance and the distance from the image capturing means 10 to the target in the initial state. By comparing the images after the distance movement, the number of distorted pixels of the image is calculated, and a difference between the number of pixels and the distance is calculated a predetermined amount to calculate the distorted distance when the robot moves.

The image capturing means 10 comprises a stereo camera for capturing left and right images.

The image capturing means 10 calculates the distance from the camera to the target by a stereo matching method (using a triangular method) using images coming from the left and right of the stereo camera.

The operation of the present invention configured as described above will be described with reference to FIG.

First, when the driving mode is selected by the user (SP1), the image capturing means 10 photographs the target image in the initial state, and the image processing means 20 receives the target image input from the image capturing means 10. Calculate the distance between the image capturing means 10 and the target object in the initial state (SP2).

Here, the image capturing means 10 is composed of a stereo camera for capturing left and right images, and calculates the distance from the camera to the target by a stereo matching method (triangular method) using the image coming from the left and right of the stereo camera.

After that, the robot moves by a certain distance for a predetermined time (SP3, SP4).

Next, the image of the initial state of the robot is compared with the image after the movement, and based on the comparison result, a distance that is displaced when the robot moves due to the size difference between the left and right wheels of the robot is calculated (SP5).

That is, as shown in FIG. 6, when the robot is actually tilted and moved, after the predetermined distance is moved, the distance to the target is calculated using the image input from the image photographing means 10, and then the target after the predetermined distance is moved. The distance difference Dy between the distance to and the target in the initial state is obtained.

Subsequently, the image of the initial state shown on the left side of FIG. 7 is compared with the image after a certain distance shift shown on the right side of FIG. 7, and the number of distorted pixels of the image is obtained. Based on the distorted horizontal axis number dx of the image after the movement and the image of the initial state, the distorted vertical axis number dy of the image after the predetermined distance is obtained.

Then, the distance Dy during robot movement is calculated by applying the difference Dy between the number of distorted pixels dx and dy of the image and the distance to the target.

[Equation]

Dx = (dx × Dy) / dy

Here, dx is the number of distorted horizontal axis pixels of the image after a predetermined distance based on the image of the initial state.

dy is the number of distorted vertical axes of the image after a certain distance from the initial state of the image.

Dy is the difference between the distance between the camera and the target after a certain distance movement and the distance between the camera and the target at rest.

Dx is the distance that changes according to the size difference between the left and right wheels when moving the robot.

Next, the distance correction value according to the distance distorted when the robot is moved is calculated (SP6), and the rotation speed of the left / right wheel is relatively controlled according to the distance correction value (SP7).

That is, the present invention compares the difference between the distance between the target in the initial state and the target after the movement, and the image in the initial state and the image after a certain distance movement to change the robot using the distorted number of pixels of the image. The distance is calculated and the rotational speeds of the left and right wheels are relatively varied using distance correction values according to the distorted distance.

The specific embodiments and embodiments made in the detailed description of the present invention are intended to clarify the technical contents of the present invention to the extent that they should not be construed as limited to these specific embodiments and should not be construed in consultation with the spirit of the present invention. Various changes may be made within the scope of the claims.

As described in detail above, the present invention compares the difference value between the distance between the target in the initial state and the target after the movement and the image after the movement in the initial state and the constant distance, and compares the number of pixels in the image. Calculate the distorted distance when the robot moves, and use the distance compensation value according to the distorted distance to change the rotation speed of the left and right wheels relatively, preventing movement errors due to the difference between the size of the left and right wheels. It works.

Claims (9)

Image capturing means for capturing an image of a target; Image processing means for processing an image captured by the image capturing means and calculating a distance from the image capturing means to the target based on the predetermined processed image; In the initial state, the first image output from the image processing means and the first distance from the image capturing means to the target, the second image output from the image processing means after a predetermined distance and the image capturing means; Drive to control the driving speed of the left wheel and the right wheel based on the calculated distance correction value by calculating the distance to be shifted during the movement based on the second distance to the target, the distance correction value according to the distance during the movement Control means for outputting a control signal; And And a driving means for driving the left wheel and the right wheel by the drive control signal. The method of claim 1, wherein the control means, The difference between the second distance from the image capturing means to the target after the fixed distance movement and the first distance from the image capturing means to the target in the initial state is obtained. Comparing two images to calculate the number of pixels to be distorted, and calculates the distance when the mobile robot moves by applying the calculated difference between the number of pixels and the distance to the following equation. Error correction device. [Equation] Dx = (dx × Dy) / dy Here, dx is the number of distorted horizontal axis pixels of the image after a predetermined distance based on the first image of the initial state, dy is the number of distorted vertical axis pixels of the image after a predetermined distance based on the first image in the initial state, Dy is the difference between the second distance and the first distance at rest, Dx is the distance that changes according to the size difference between the left and right wheels when moving the robot. The method of claim 1, wherein the video recording means, Left and right wheel size error correction device, characterized in that the stereo camera to shoot the left and right images. The method of claim 1, wherein the video recording means, A device for correcting left / right wheel size errors of a mobile robot, comprising calculating a distance from a camera to a target by a stereo matching method using an image input from left and right of a stereo camera. If the driving mode is selected by the user, calculating a first distance between the image capturing means and a target in an initial state based on the target image photographed by the image capturing means; Moving the mobile robot for a predetermined time; Based on a first image of the initial state of the mobile robot and the calculated first distance, a second image photographed by the image photographing means after moving for a predetermined time, and a second distance from the image photographing means to the target; Calculating a distance that is distorted upon movement; Calculating a distance correction value according to the calculated distance during the movement; And And controlling the rotational speeds of the left and right wheels based on the calculated distance correction value. The method of claim 5, wherein the video recording means, A left and right wheel size error correction method of a mobile robot, characterized in that the stereo camera to shoot the left and right images. The method of claim 5, wherein the calculating of the first distance between the image photographing means and the target in the initial state comprises: Compensating the left and right wheel size error of the mobile robot, characterized in that it comprises the step of calculating the distance from the camera to the target in a stereo matching method using the image coming from the left and right of the stereo camera. The method of claim 5, wherein the calculating of the distorted distance during the movement comprises: Calculating a second distance to the target based on the image photographed by the image photographing means after a predetermined distance; Obtaining a difference between a second distance to the target after the constant distance and a first distance to the target in an initial state; Calculating a number of distorted pixels of the image by comparing the first image in the initial state with the second image after a predetermined distance; And And calculating a distance which is distorted when the mobile robot moves by performing a predetermined calculation process on the calculated number of pixels and the distance difference. The method of claim 8, wherein the calculating of the distorted distance when the mobile robot moves is performed. The left / right wheel size error correction method of the mobile robot, characterized in that for calculating the distance distorted when the mobile robot moves by the following equation. [Equation] Dx = (dx × Dy) / dy Here, dx is the number of distorted horizontal axis pixels of the image after a predetermined distance based on the first image of the initial state, dy is the number of distorted vertical axis pixels of the image after a predetermined distance based on the first image in the initial state, Dy is the difference between the second distance and the first distance, Dx is the distance that changes according to the size difference between the left and right wheels when moving the robot.

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