KR100590210B1 - Method for mobile robot localization and navigation using RFID, and System for thereof - Google Patents

Abstract

The present invention relates to a mobile robot, and more particularly, to a location recognition and driving method of an indoor mobile robot using an active beacon and a mobile robot system using the same.

According to an aspect of the present invention, there is provided a method for recognizing and driving a vehicle, the method comprising: generating a route according to the driving command when a driving command is received; A second step of discovering a specific RFID tag and acquiring an image of an LED on and an off state of the specific RFID tag; And determining a position recognition and a moving direction angle of the robot by using the difference image between the image of the LED on state and the image of the off state.

The robot covered by the present invention includes any type of robot having mobility up to a humanoid robot, including a wheeled robot.

Mobile Robot, Position Recognition, RFID, Docking Station

Description

Mobile robot location recognition and driving method using RDF and mobile robot system using the same {Method for mobile robot localization and navigation using RFID, and System for             

1 is a view showing a setting example of the coordinate system and the global coordinate system of the mobile robot,

2 is a view showing a configuration example of a system using RFID;

3 is a view showing an RFID tag with a built-in LED,

4 is a view showing the geometric relationship between the coordinate system and the RFID tag of the camera mounted on the mobile robot,

5 shows a mobile robot according to an embodiment of the present invention, and shows a relationship between a camera coordinate system and a robot coordinate system mounted on the mobile robot;

6 is a flowchart showing a position recognition process of a robot according to an embodiment of the present invention;

FIG. 7 is a diagram illustrating a driving method using a direction angle obtained by the process illustrated in FIG. 6;

8A to 8C illustrate an example of image processing for obtaining a difference image according to an embodiment of the present invention;

9 is a diagram showing an example of triangulation for homing a mobile robot to a docking station according to another embodiment of the present invention.

The present invention relates to a mobile robot, and more particularly, to a location recognition and driving method of an indoor mobile robot using an active beacon and a mobile robot system using the same.

In general, in order to realize autonomous robot navigation, a localization method capable of immediately grasping the location information of the robot in the robot's operating environment, from which a movement path in the operating environment is generated and It consists of a guidance method for controlling the robot platform along the route and an environment map building method for collecting and managing information on the robot's operating environment.

First, the environmental map can be largely divided into a metric map and a topological map. In the case of the metric path generation method, the robot path is optimized by optimizing an arbitrary predetermined performance index for the robot path generated from the quantitatively expressed robot environment data. Refers to a series of methods to select. Representative examples include an environment map having a grid structure and an optimal control method in consideration of an optimal path or kinematic structure of the robot platform in the environment map.

On the other hand, in the case of the topological path generation method, a graph-type environmental map describing the spatial relationship between each feature point based on a characteristic position in the robot environment, for example, furniture, appliances, and door entrances, is used. From this, you can create a route, for example, "move past the door and next to the refrigerator."

As described above, in order for the robot to travel along a given route or to create a new route, information about the current position of the robot is essential, and the robot should be able to check information about its position at any time. For this purpose, artificial landmarks can be installed in the robot's operating environment, or natural landmarks can be extracted from the environment.They can emit light or RF signals like active markers. A method of determining the position of the robot can be used by measuring the direction of arrival of the signal.

)이다. 상기 위치 정보는 도 1에 예시한 로봇 환경내에 설정된 임의의 전역 좌표계 (world coordinate frame)

를 기준으로 정의된다.The information targeted by the robot localization method includes two-dimensional coordinate values (x _R , y _R ) of the robot and information about the robot's direction angle, that is, the heading direction, as illustrated in FIG. 1.

)to be. The position information may be any world coordinate frame set in the robot environment illustrated in FIG. 1.

It is defined based on.

In relation to the robot positioning method, the Korean patent application (Application No. 10-2001-0059501) discloses an illuminance value of the robot environment when an artificial landmark is found through an image processing process and the positioning information of the robot is calculated therefrom. In particular, a method and apparatus for maintaining a constant illumination illuminance value for an artificial marker point are described. In the above patent, the result of the image processing is very closely influenced by the peripheral illumination value in the artificial marker point discovery step using the camera, so that when the illumination value is measured lower than the preset minimum value or the user arbitrarily adjusts the illumination value, It is invented so that an artificial marker point can always be found by supplying power to a light emitting unit installed near the marker point.

In addition, the Republic of Korea patent (application number: 10-2001-0059501) is a ceiling-directed (ceiling directed) camera for observing artificial markers installed on the ceiling to calculate the position information of the robot and the front to recognize obstacles or objects in front It describes a series of methods for separating forward looking cameras and calculating the robot's current position from an artificial landmark found on the ceiling. In another prior patent, the Korean patent (application number: 10-2002-0019039) installs a plurality of sensor cells with unique location information on the floor in the robot environment, and sends and receives RF (Radio Frequency) signals while the robot is driving. It describes a method of estimating the position information of the robot by reading the position information of the sensor cell installed under the robot platform.

Meanwhile, in US Patent Application Publication (US2004 / 0158354, Lee et al.), The relative distance and direction angle between the robot and the docking station can be measured for homing to a docking station for charging the robot. Ultrasonic positioning methods are described. The patent also belongs to the scope of the robot positioning method, but describes a method of solving the robot position information calculation using two ultrasonic sensors in the case of the docking step of the robot.

Recently, with the active development of technologies related to RFID (Radio Frequency IDentification), international standardization related to RFID is progressing, and in particular, it is actively applied to the fields of logistics and location recognition. Any RFID system is a reader that generates an RF signal and interprets an RF signal received from a nearby RFID tag, as illustrated in FIG. 2, coupled to a signal transmitted from the RFID reader. It consists of an RFID tag that transmits its own unique identification number and an antenna mounted on the RFID reader. The computer operating the RFID reader may be connected to itself or a remote server to provide various services based on tag information, that is, services such as logistics management and location checking. The RFID system can only activate RFID tags located within the detection area of the reader antenna and for this reason can only provide information on whether a particular RFID tag is present around the RFID reader.

를 추정하는 방법에 대해 기술하고 있다. In US Patent Publication (US 2003/0236590, Park et al.) Related to robot positioning using RFID, RFID tags are manufactured in an array form and installed on the bottom surface of the robot environment, and a plurality of bottom surfaces of the robot platform are provided. Equipped with an RFID reader, the robot's current position from the unique identification number of the RFID tag detected as the robot proceeds.

It describes how to estimate.

As another example of using RFID, Japanese Laid Open Patent Application (P2004-230539A) discloses a robot manipulator relative to the RFID tag by triangulation at three different points that do not form a straight line. A method for estimating position and attitude is disclosed. In addition, Japanese Laid Open Patent Application (P2004-160630A) discloses a method of controlling a corresponding robot behavior based on information read from an RFID tag. In Japanese Patent Application Laid-Open (P2004-216513A), a method of distinguishing a plurality of users with an RFID tag by using a received RFID, and at the same time, using a signal strength from the RFID tag to communicate with the closest user and a robot It is describing.

Also, the preceding paper "D. Hanhel et al.," Mapping and localization with RFID technology, IEEE Int. conf. Robotics and Automation, pp. 1015-1020,2004 "shows an example of applying the method of particle filtering by estimating the two-dimensional position of the RFID tag attached in the robot environment map obtained in advance and mapping it on the map. Tsukiyama, "Global navigation system with RFID tag," Proc. SPIE, vol. 4573, pp. 256-264, 2002 "proposed a method of obtaining a topological map of an RFID tag attached to a robot environment and calculating a route for robot travel from it. Here, the direction angle of the robot is determined by the wall surface from the camera mounted on the robot. The direction of the edge component of the bottom surface is extracted and corrected.

In addition, the preceding article "V. Kulyukin et al," RFID in robot-assisted indoor navigation for the visually impaired, "IEEE Int. Conf. On Intelligent Robots and Systems, PP. 1979-1984, 2004 The following example shows how to install a tag and write an RFID sequence that must pass through the robot path. Here, the moving direction of the robot was determined by calculating the potential field from distance information obtained from a laser scanner mounted on the robot. In addition, K. Yamano et al, "Self localization of mobile robots with RFID system by using support vector IEEE Int. Conf. on Intelligent Robots and Systems, pp. 3756-3761, 2004, "In order to estimate the quantitative position of the robot, a method of estimating the qualitative position of the robot by classifying patterns of a plurality of RFID tag signals received by the RFID reader by a support vector machine. .

As described above, in the robot positioning method and the robot driving method using the recent RFID technology, a heterogeneous sensor such as a camera or a laser scanner is used to determine the qualitative position of the robot from the RFID tag signal and estimate the direction angle of the robot. I'm using it. The method of estimating the direction angle is difficult to implement easily due to physical limitations inherent in the sensor, for example, a limited viewing angle in the case of a camera, an uncertainty due to a change in illuminance, and a high price of the sensor itself in a laser scanner.

The widespread applicability of recent RFID technologies is expected to keep the prices of RFID tags and readers low. Various RFID applications are currently being released, including the launch of mobile phones with RFID readers, and with this trend, RFID tags will be attached to household furniture and other various items including home appliances. Therefore, the object recognition problem in the robot environment, which is a limitation of the existing robot sensor, is expected to be solved very simply by incorporating the RFID technology. However, due to the characteristics of the RFID system, only the qualitative position information of the RFID tag can be provided, and thus, a means for obtaining information on the direction angle of the robot in addition to the qualitative position information is required for the purpose of robot positioning.

Therefore, the object of the present invention has been proposed by the necessity as described above, in the robot positioning system using RFID, it is possible to immediately estimate the information on the position and direction angle of the robot at the current position, and accordingly route planning and robot driving It is to provide a mobile robot position recognition and driving method that can be easily made and a mobile robot system using the same.

Mobile robot system according to the present invention for achieving the above object,

An RFID tag attached to a predetermined position in any indoor environment and having an LED; It has an RFID reader and a camera, and sends a signal to the RFID reader to turn on / off the LED provided in the RFID tag, the first image and the LED is turned off And a mobile robot configured to acquire a second image by the camera and determine a location recognition and driving method by using the obtained first image and the difference image of the second image.

The method according to the present invention for achieving the above object,

Receiving a driving command, generating a route according to the driving command; A second step of discovering a specific RFID tag and acquiring an image of an LED on and an off state of the specific RFID tag; And determining a position recognition and a moving direction angle of the robot by using the difference image between the image of the LED on state and the image of the off state.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

The mobile robot system to which the present invention is applied is largely a mobile robot, a plurality of RFID tags attached to a predetermined position in an indoor environment, and having LEDs, and having LEDs embedded in themselves for charging and waiting for the robot and being aligned with each other. It comprises a docking station with three or more RFID tags attached to it that are not placed on it. As described below, the mobile robot includes an RFID reader and an antenna, a sensor unit for detecting an obstacle, a camera for measuring a direction angle of the robot, and a robot platform, and recognizes and travels therein according to an embodiment of the present invention. Location recognition and travel control means for carrying out the method. Hereinafter, the mobile robot system and the position recognition and driving method of the mobile robot according to the present invention will be described in detail.

The propagation characteristics of RFID tags are mostly omnidirectional or very wide beam widths. Therefore, even if the robot finds a specific RFID tag while driving, the relative direction angle of the robot with respect to the RFID tag is not known. In this case, the robot must proceed in any direction to find the next RFID tag on a given path sequence and estimate the direction of the robot from the ID of the first RFID tag found. It becomes possible.

In order to solve the above problems, the robot position recognition and driving method using RFID according to the present invention uses an RFID tag 310 having a built-in LED (Light Emitting Diode) 310 as illustrated in FIG. 3. As described above, the RFID tag 310 equipped with the LED is disposed at any position of the indoor environment. The mobile robot acquires an LED image using a camera mounted on the robot to estimate the relative robot direction angle from an arbitrary RFID tag, and then estimates the direction angle of the robot through an image processing step.

는 카메라 렌즈 중심에 설정된 카메라 좌표계를 나타내며,

는 2차원 이미지 평면의 좌표계,

는 RFID 태그에 장착한 LED 의 좌표값을 상기 카메라 좌표계에 대해 나타낸 것이다. 상기 도 4에서 2차원 이미지 평면상에 맺히는 LED의 픽셀 좌표값은

로 나타내었다. 상기 도 4에서

는 카메라 초점 거리,

,

는 각각 카메라 좌표계와 RFID 태그간의 고도각 (elevation angle), 방위각 (azimuth angle) 을 나타내며 각각의 각도는 하기 <수학식 1> 과 <수학식 2>를 이용하여 구해진다.4 is a diagram showing the key relationship between the RFID tag embedded with the LED and the camera mounted on the mobile robot looking at the LED. In FIG. 4 above

Indicates the camera coordinate system set at the center of the camera lens.

Is the coordinate system of the two-dimensional image plane,

Denotes the coordinate value of the LED mounted on the RFID tag with respect to the camera coordinate system. In FIG. 4, the pixel coordinate values of the LED formed on the two-dimensional image plane are

Represented by. In FIG. 4 above

The camera focal length,

,

Represents an elevation angle and an azimuth angle between the camera coordinate system and the RFID tag, respectively, and the angles are obtained using Equations 1 and 2 below.

In order to apply the above Equations 1 and 2, the camera mounted on the mobile robot must be calibrated in advance.

5 shows a mobile robot according to an embodiment of the present invention, and shows a relationship between a camera coordinate system and a robot coordinate system mounted on the mobile robot.

만큼 로봇을 회전시켜 로봇의 진행 방향과 RFID 태그의 정면을 일치시킬 수 있다. Referring to FIG. 5, the mobile robot robot platform 500, the camera 520, and the location recognition and travel control means 510 for performing the location recognition and driving method according to the present invention are configured. In addition, although not shown in the drawings, the RFID reader or the RFID reader for generating an RF signal and the antenna, and further comprises a sensor for detecting the obstacle. Hereinafter, for convenience of explanation, it is assumed that the camera coordinate system and the robot coordinate system are spaced apart by the distance H while the rotation axis y _R of the robot and the camera coordinate axis x _R coincide. Therefore, the relative azimuth difference between the RFID tag and the camera obtained by Equation 1

By rotating the robot as much as possible, the moving direction of the robot and the front of the RFID tag can be matched.

6 is a flowchart illustrating a position recognition process of a robot according to an exemplary embodiment of the present invention, and FIG. 7 is a diagram illustrating a driving method of a robot using a direction angle obtained by the process illustrated in FIG. 6. That is, the process of Figure 6, in the case of using the robot position recognition method using the RFID according to the present invention when the movement command is given from the current position to any destination for its own driving purpose of the user or the robot moves at the current position A diagram showing a process of estimating the direction angle of a robot.

In the mobile robot according to the present invention, the method for recognizing a position and driving a vehicle may include generating a route according to the driving command, discovering a specific RFID tag, and turning on an LED included in the specific RFID tag. A second step of acquiring an image of the state and an image of the off state; And a third step of determining the position recognition and the moving direction angle of the robot by using the difference image between the image of the LED on and the image of the off state. 6 and 7, S601 to S602 correspond to a first step, S603 to S607 correspond to a second step, and S608 to S610 correspond to a third step.

Hereinafter, a detailed description will be given with reference to FIGS. 6 and 7. In the following description, the control of the mobile robot is controlled by the position recognition and travel control means.

를 계산한다. 이 때, RFID #1과 RFID #2의 전역 좌표값은 로봇 환경내에 임의로 설정한 전역 좌표계에 대해 표현된 값이 된다. First, in step S601, when a driving command is given, for example, "come to the sofa placed in the living room", the mobile robot checks the RFID tag closest to the sofa on a predetermined environment map. Thereafter, in step S602, the RFID tag mounted on the robot is used to find the RFID tag closest to the robot at the current location. This process recognizes the first RFID tag found as the nearest RFID tag while gradually increasing the strength of the signal transmitted from the RFID reader from the weakest step. If a plurality of RFID tags are found, one is arbitrarily selected. As illustrated in FIG. 7, when the RFID tag located closest to the current robot's position obtained in step S602 of FIG. 6 is RFID # 1 and the RFID tag closest to the destination is RFID # 2, the RFID # is created in the robot environment map prepared in advance. Direction vector between 1 and RFID # 2

Calculate At this time, the global coordinate values of the RFID # 1 and the RFID # 2 are values expressed for the global coordinate system arbitrarily set in the robot environment.

After the steps S601 and S602, the robot calculates a relative direction angle with respect to the nearest RFID tag, for example, RFID # 1. Since the detected RFID # 1 can exist at any position within the detection area, the robot rotates in place when the camera is fixed to the robot to acquire the image of the LED on with the camera, but the overlapping area between the images obtained at each rotation This should be. If the camera itself has a scanning function, the camera can be rotated.

In step S603, the LED included in the specific RFID tag is turned on by the RFID reader included in the mobile robot, and in step S604, the first image of the LED is turned on by using the camera provided in the mobile robot. . Thereafter, in step S605, the LED included in the specific RFID tag is turned off by the RFID reader included in the mobile robot, and in step S606, the second image of the LED is turned off using the camera provided in the mobile robot. Acquire it. Next, in operation S607, a difference image between the first image and the second image is obtained.

크기의 영상을 제공하는 카메라의 경우 하기 <수학식 3>과 같이 표현할 수 있다.That is, after transmitting the RF signal to the RFID reader mounted on the robot in steps S603 to S605 to obtain an image and stop transmitting the RF signal in the same posture to obtain the same scene. In operation S607, a difference image between two images is acquired. 8A illustrates an image in which LEDs are held together at the viewing angle of the camera at the current position of the robot through steps S603 and S604. 8B illustrates an example in which the robot stops transmitting RF signals at the same point through steps S605 and S606 to turn off the LED and acquires a state at this time with a camera mounted on the robot. Subsequently, in step S607, when the difference image is calculated from FIGS. 8A and 8B, the position of the LED image can be easily identified as shown in FIG. 8C. At this time, the relation for obtaining the difference image is

In the case of a camera providing an image of a size, it may be expressed as in Equation 3 below.

는 상기 제1영상의 픽셀위치 (i,j)에서의 밝기값,

는 상기 제2영상의 픽셀위치 (i,j)에서의 밝기값에 해당한다. 상기 <수학식 3>을 적용함에 있어 영상 잡음을 제거하거나 글레어(glare)에 의한 위치 계산시의 오차를 줄이기 위해 적절한 필터링 단계를 거칠 수 있다.In Equation 3,

Is a brightness value at the pixel position (i, j) of the first image,

Corresponds to a brightness value at the pixel position (i, j) of the second image. In applying Equation 3, an appropriate filtering step may be performed to remove image noise or reduce an error in calculating a position by a glare.

In step S608 of FIG. 6, it is determined whether the LED image is found in the difference image between the first image and the second image, and if the LED image does not exist in the difference image, the mobile robot or the camera is rotated by a predetermined angle. After that, the steps S603 to S608 are repeated until the LED is found.

이미지를 몇 개의 패치형태의 영역으로 구분하고 각 영역의 밝기값을 단순 합한 후 미리 설정한 임계값 (threshold value) 이상인지를 조사한다. 만약 기설정한 임계값 이상인 경우 LED가 해당 영역에 존재하는 것으로 판단하고 원래의

영상의 u, v가 증가하는 방향으로 스캔하는 등의 방식으로 간단히 검출할 수 있다. 상기 방식으로 LED 위치를 검출한 후 S610단계에서, <수학식 1>을 이용하여 로봇과 상기 RFID #1 태그간의 상대적인 방위각을 계산하게 된다.In step S608, the position of the LED image is

The image is divided into several patch-shaped regions, and the brightness values of each region are simply summed, and then examined to see whether or not it is above a predetermined threshold value. If it is over the preset threshold, it is determined that the LED exists in the area and

It can be detected simply by scanning in the direction of increasing u and v of the image. After detecting the LED position in the above manner, in step S610, the relative azimuth angle between the robot and the RFID # 1 tag is calculated using Equation (1).

방향을 따라 RFID #1이 감지되는 거리내의 무한개 지점에 위치할 수 있다. 따라서 현재 로봇 위치로부터 목적지 RFID #2까지의 직선 경로에 해당하는

를 계산할 수 없게 된다. Meanwhile, as shown in FIG. 7, even when the robot discovers RFID # 1 and calculates relative azimuth information, information about the actual distance between the robot and RFID # 1 may not be known. That is, the robot is as shown in FIG.

Along the direction, the RFID # 1 may be located at infinite points within the detected distance. Therefore, the straight path from the current robot position to the destination RFID # 2

Cannot be calculated.

만큼 로봇을 회전시킨 후의 진 행 방향을 따라 로봇을 이동하는 것이 된다. 로봇은 상기 진행 방향을 따라 이동 중에 로봇에 탑재된 RFID 판독기를 이용하여 RFID #2를 계속 탐색하고 만약 도 7에 나타낸 바와 같이 로봇이

위치에서 RFID #2가 응답하여 발견되는 경우 S603내지 S610단계를 반복하여 RFID #2로의 진행 방향을 새롭게 정한다.In order to solve the above problem, the robot position recognition and driving method using RFID according to the present invention drives the robot to be parallel to the direction vector from the known RFID # 1 to the destination RFID # 2. This is in Figure 7

The robot is moved along the progress direction after the robot has been rotated. The robot continues to search RFID # 2 using the RFID reader mounted on the robot while moving along the traveling direction.

If RFID # 2 is found in response to the location, steps S603 to S610 are repeated to newly determine the moving direction to RFID # 2.

까지 도달하여 목적지에 도착하게 된다. 이 때, 로봇의 RFID #2로의 진행 방향은 LED 영상의 픽셀 위치를 특정 지점에 머무르도록 로봇을 제어함으로써 목적에 따라 정면을 취하거나 기타 다양한 각도로 진입할 수 있다.By repeating the process of acquiring the LED image and obtaining the pixel position in the image during the movement, the robot acquires the direction angle information for rotating the robot in the direction of RFID # 2,

You will arrive at your destination. At this time, the direction of the robot's progression to RFID # 2 may control the robot to maintain the pixel position of the LED image at a specific point, so that the robot may take a front face or enter various other angles according to the purpose.

9 is a view showing a robot position recognition and driving method using RFID according to another embodiment of the present invention. In other words, the mobile robot homing to the docking station (docking station) for the purpose of charging the battery mounted therein. The docking station is equipped with three or more RFID tags that have their own LEDs and are not in line. At this time, the coordinate value of each LED is to be expressed for any position in the docking station.

First, the robot searches for any one of the RFID tags attached to the docking station with an RFID reader mounted on the robot if it needs to move to the docking station, for example for charging purposes. When the corresponding RFID tag is found, three LED tags are called in order to turn on and off each LED in order to homing from the current position to the docking station. At this time, the camera mounted on the robot is used to acquire the scenes of each LED on and off state, and after obtaining the difference image, the pixel position of the LED image is calculated therefrom. The direction angle of the robot for each LED is calculated by using Equation 1 from the pixel position of the obtained LED image. At this time, to obtain each LED image may be obtained three LED images by using a method such as searching the RFID tag at the same time. In this case, the relative direction angle of the robot for each LED image is calculated from one difference image.

는 각각 LED1, LED2, LED3로부터 측정된 로봇의 상대적인 방향각을 나타낸다. LED1, LED2, LED3는 도킹 스테이션내에 설정한 좌표계 {x_D, y_D}로부터 표현된 좌표값을 가지고 있으므로 로봇의 현재 위치 및 방향각은 삼각 측량 (triangulation)을 통해 도 9에 예시한 것처럼

와

로 표현된다. 따라서, 로봇이 도킹 스테이션으로 호밍시 상기

만큼 회전을 한 후, |

|의 거리를 진행하여 올바른 위치로 진입할 수 있다. In Figure 9,

Are the relative orientation angles of the robot measured from LED1, LED2 and LED3, respectively. Since LED1, LED2, and LED3 have coordinate values expressed from the coordinate system {x _D , y _D } set in the docking station, the current position and orientation angle of the robot are as shown in FIG. 9 through triangulation.

Wow

It is expressed as Thus, when the robot homs to the docking station,

After making enough turns, |

You can enter the correct position by going through the distance of |

While the invention has been described above based on the preferred embodiments thereof, these embodiments are intended to illustrate rather than limit the invention. It will be apparent to those skilled in the art that various changes, modifications, or adjustments to the above embodiments can be made without departing from the spirit of the invention. Therefore, the protection scope of the present invention should be construed to include not only the appended claims but also all of the above-described changes, modifications or adjustments.

As described above, the present invention enables the robot to travel by finding a nearby RFID tag and acquiring the attitude information of the robot from the robot. By using RFID, it is possible to realize highly reliable robot driving and to have a very fast response speed for robot positioning information, compared to the case of using only conventional robot sensors such as an ultrasonic sensor, a laser scanner, and a camera.

In the robot position recognition and driving method using RFID according to the present invention, only the relative direction angle between RFID tags is input without the actual distance between the RFID tags in the step of inputting the absolute position of the RFID tags. It is very simple to construct.

Therefore, the robot position recognition and driving method using RFID according to the present invention can be applied to indoor home environments including factories and offices by attaching RFID tags to indoor walls or other points, and additional construction for RFID system installation is required. So it's very economical.

Claims (10)

A mobile robot system using RFID that operates in any indoor environment, An RFID tag attached to a predetermined position in any indoor environment and having an LED; It has an RFID reader and a camera, and sends a signal to the RFID reader to turn on / off the LED provided in the RFID tag, the first image and the LED is turned off And a mobile robot for acquiring a second image with the camera and determining a location recognition and driving method using the obtained first image and the difference image of the second image. The method of claim 1, And an RFID tag having at least three LEDs attached thereto, the RFID tag further comprising a docking station for battery charging and homing of the mobile robot. The method of claim 2, wherein the mobile robot And turning on the LED of the RFID attached to the docking station through the RFID reader, acquiring an LED image, and moving to a home position of the docking station using a triangulation method. In an indoor environment in which an RFID tag is attached at an arbitrary position, as a method for recognizing and traveling a mobile robot using RFID, Receiving a driving command, generating a route according to the driving command; A second step of discovering a specific RFID tag and acquiring an image of an LED on and an off state of the specific RFID tag; And determining a position recognition and a moving direction angle of the robot by using a difference image between the image of the LED on and the image of the off state. The method of claim 4, wherein the LED provided in the RFID tag is turned on / off by an RFID reader provided in the mobile robot. According to claim 4, After the mobile robot rotates to be parallel to the direction between the RFID tag of the current position and the RFID tag of the destination, and transmits an RF signal for the RFID tag until the RFID tag of the destination is found, If the tag is found, repeating the first step to the third step at the point, to correct the traveling direction angle of the mobile robot, characterized in that the location of the mobile robot. The method of claim 4, wherein the second step is Turning on the LED included in the specific RFID tag by the RFID reader provided in the mobile robot; Acquiring a first image of a state where an LED is turned on by using a camera provided in the mobile robot; Turning off the LED provided in a specific RFID tag by an RFID reader provided in the mobile robot; Acquiring a second image of a state where the LED is turned off by using a camera provided in the mobile robot; And a step of acquiring the difference image between the first image and the second image. The method of claim 7, wherein the difference image is represented by the following equation.

Position recognition and driving method of a mobile robot, characterized in that calculated using. here,

Is the brightness value at the pixel position (i, j) of the first image,

Is a brightness value at pixel position (i, j) of the second image. The method of claim 4 or 7, wherein the third step is Determining whether an LED image exists in the difference image between the image of the LED on state and the image of the off state; If the LED image does not exist in the car image, the step of rotating the mobile robot or the camera by a predetermined angle, comprising the step of returning to the second step comprises the step of recognizing and driving the mobile robot. 10. The method of claim 9, wherein if the LED image is present in the difference image, the position of the LED in the image is calculated,

A method of recognizing and driving a mobile robot, the method comprising: calculating a relative azimuth angle between the mobile robot and a specific RFID tag by using a.

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