KR20070061218A - Method and device for recognizing the location of indoor robot - Google Patents

Abstract

A method and a device for recognizing the location of a robot indoors are provided to facilitate the installation and reduce costs, by using two transmitters. A device for recognizing the location of a moving robot(100) indoors includes a first transmitter(110) and a second transmitter(120). The first transmitter delays a received signal by a predetermined time and transmits the delayed signal. The second transmitter delays the received signal by a predetermined time and transmits the delayed signal. The moving robot transmits the signal to the first and second transmitters and identifies its location based on the time required for receiving the signals from the first and second transmitters, respectively.

Description

Method and device for recognizing the location of indoor robot}

1 is a diagram illustrating a system configuration for locating a mobile robot as a preferred embodiment of the present invention.

2 conceptually illustrates a distance calculation method when recognizing an indoor position by a mobile robot.

3 is a diagram illustrating an internal configuration of a positioning system as a preferred embodiment of the present invention.

4 shows a process flow diagram of localization of the present invention.

5 is a flowchart for identifying a position in a mobile robot using a transmitter.

The present invention relates to an apparatus and method for recognizing a position of a robot in a room, and more particularly, to a technical concept of determining a position of a mobile robot using two transmitters.

The position recognition method of the robot is divided into a relative method and an absolute method. Commonly used relative position recognition method is using an encoder installed on the wheel and a method using a camera, etc. If an error occurs due to the sliding of the wheel or idle, and the brightness of the light or similar shape is recognized Errors occur and these errors continue to accumulate.

In order to solve the problem of the relative position recognition method, the robot uses the absolute position recognition method complementarily. Commonly used absolute position recognition methods include a method using an infrared signal, a method of measuring the strength of an RF signal, a method using an ultrasonic signal, and the like.

In the method of using the infrared signal, the infrared sensor is attached to the ceiling, the infrared emitter is attached to the robot and moved, and the infrared emitter periodically transmits its own identification number to the ceiling using infrared rays, and uses the received signal. It is a technology to identify the position of a robot. This method is used as a method of detecting the presence of a robot near the receiver rather than an accurate position recognition because the resolution of infrared rays is small and the location is difficult to be detected when obstructed by obstacles such as furniture.

The technology of determining the location by measuring the strength of the RF signal is statistically analyzed by measuring the strength of the signal transmitted from the base station or broadcasting station transmitting the wireless data, the access point (AP) of the wireless LAN at each measurement point, It is a technology to determine the position of the robot by measuring how much strength signal is input from the current position using the analysis result. In this method, the signal strength changes from time to time according to various environmental changes such as temperature and humidity, and the precision is about 1-3m, which is not suitable for determining the exact position of the robot indoors.

The method of using the ultrasonic signal is to install an ultrasonic receiver on the ceiling, attach the ultrasonic generator to the robot, calculate the distance by measuring the time from the generator to the receiver, and use the signal delay received from the various receivers based on this distance. It is a technique to determine the position of the robot. This method can detect the propagation delay relatively accurately because the sound wave propagation speed is relatively slow, but has a disadvantage of being affected by furniture and surrounding objects.

In order to solve the above problems, the present invention provides an apparatus and method for recognizing position using a UWB signal in a transmitter as an absolute position recognition method used to identify a position in a mobile robot. In addition, the system using the present UWB signal requires synchronization between the sensor installed on the ceiling and the robot, and at least three sensors must be installed in a non-linear shape, which is complicated to install and expensive. This problem is solved.

In a preferred embodiment of the present invention, the positioning system comprises: a first transmitter for delaying a received signal for a preset? T1 time and then transmitting it; A second transmitter for delaying the received signal after the ΔT2 time period and transmitting the received signal; and transmitting the signal to the first and second transmitters, respectively, from the first and second transmitters. And a mobile robot that determines its own location based on the time of receiving each of the signals.

The first and second transmitters may be disposed on the same straight wall surface, and the straight wall surface may be positioned on the outermost movement path of the mobile robot.

Also preferably, the current position in the mobile robot is calculated through the following equation,

(x-X1) ² + (y-Y1) ² + Z1 ² = (c * (T1-ΔT1)) ²

(x-X2) ² + (y-Y2) ² + Z2 ² = (c * (T2-ΔT2)) ²

In this case, (x, y, 0) is the current position of the mobile robot, (X1, Y1, Z1) is the position of the first transmitter, (X2, Y2, Z2) is the position of the second transmitter, T1 is The time required until the signal is transmitted from the mobile robot to the first transmitter, T2 is the time required until the signal is transmitted from the mobile robot to the second transmitter, and c is the transmission speed of the signal. It is characterized by.

In another preferred embodiment of the present invention, the positioning mobile robot is a device for locating a position in a mobile robot having a first and a second transmitter installed on the same straight wall of the outermost path that the robot can move. A transmitter for transmitting a signal to each of the first and second transmitters; A receiver which receives a signal from each of the first and second transmitters; And a position detection unit for calculating a position based on each time required for transmitting the signal to each of the first and second transmitters and receiving the signal.

In another preferred embodiment of the present invention, a method for determining the position of a robot moving in an indoor environment in which a first transmitter and a second transmitter are provided may be performed by moving the robot from the mobile robot to the first and the second transmitter. Transmitting a signal; Delaying the signals received at each of the first and second transmitters for ΔT1 and ΔT2 times, respectively, and then transmitting the signals to the mobile robot; And determining the position of the mobile robot based on each time required for transmitting the signals from the mobile robot to the first and the second transmitter and then receiving the signal again.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the same elements among the drawings are denoted by the same reference numerals and symbols as much as possible even though they are shown in different 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.

FIG. 1 is a diagram illustrating a system configuration for locating a mobile robot in a preferred embodiment of the present invention, and is configured to identify a position in a robot moving indoor environments using two transmitters.

In the present invention, the driving environment of the mobile robot 100 is limited to the room, and the first and second transmitters 110 and 2 may be disposed on an outermost straight path (eg, a straight wall) of the mobile robot (not shown). 120).

Generally, three transmitters are used for position recognition of a mobile robot, but in the present invention, the driving environment of the robot is limited to an indoor space. The use of only two transmitters reduces the cost of implementing mobile robot positioning in the room. In addition, it is possible to minimize the error by calculating the correct value of ΔT1 and ΔT2, which are the delay time of the transmitter which tends to generate an error, and correcting it to a preset value. A method of determining the position of the mobile robot using only two transmitters will be described in detail with reference to FIG. 2.

In a preferred embodiment of the present invention, the positioning system includes a mobile robot 100, a first transmitter 110, and a second transmitter 120.

In the positioning system, the mobile robot 100 is a target for position recognition, and the first and second transmitters 110 and 120 are beacon devices for processing signals for position recognition of the robot.

The mobile robot 100 transmits a position request signal to each of the first and second transmitters 110 and 120. After receiving the position request signal transmitted by the mobile robot, each of the first and second transmitters 110 and 120 transmits the position transfer signal to the mobile robot after a predetermined time (ΔT1 and ΔT2 times). Send.

The specific time (ΔT1 and ΔT2 times) is set larger than the time required to receive the signal in the first and second transmitters 110 and 120 and the time required to transmit the signal.

Moving robot 100 comprises a first transformer mirror 110 and the respective time at which second position the transmitter mirror 120 required transmit a green light first transport mirror (110) from (T _{1 agent,} T _{2 bit)} and the 2 each time one receives a carrier signal from the position transmitter mirror 120 calculates the time required to (T _{1 a, the} T _2).

That is, the time required for transmitting the signal from the mobile robot 100 to the first transmitter 110 and then receiving the signal T1 = T _{1 is} equal to -T _{1 .} time T2 = T ₂ to the time it receives one _after - a T _{2 agent.}

After that, the first transmitter is used by using the times T1-ΔT1 and T2-ΔT2 except for the times ΔT1 and ΔT2 delayed by the first and second transmitters 110 and 120, respectively. The distance to the 110 and the second transmitter 120 is obtained. This will be described in more detail with reference to FIG. 2.

As a preferred embodiment of the present invention, a UWB (Ultra Wide Band) signal is used as a communication method when transmitting a position request signal and receiving a position carrier signal between the mobile robot 100 and the transmitters 110 and 120. That is, the UWB signal may be used as the position request signal transmitted from the mobile robot to the transmitters and the position carrier signal transmitted from the transmitter to the mobile robot.

UWB method is similar to ultrasonic system, but UWB is very suitable for location recognition system because it has very good distance resolution and can accurately estimate the travel time of the signal. UWB signal operates at low center frequency, It is excellent in location recognition accuracy even in indoor or shadowed environment which is non-LOS (Line-of-Sight). In addition, unlike infrared or ultrasonic waves that must be separately configured in a closed space, the UWB signal can penetrate a wall, thereby reducing the number of transmitters installed.

In addition, unlike the existing RF communication technology, since it does not use a carrier, it can be designed as a simple radio structure that does not require an IF module, and thus, it is a method that is attracting much attention.

However, it should be noted that the UWB signal is an example of a signal that is preferably used in the present invention, and the use of other signals is not limited.

As derived from the above description, in the present invention, a separate synchronization device or method for matching the position carrier signal received from the first and second transmitters 110 and 120 in the mobile robot 100 is provided. It is not necessary and the error is minimized by obtaining and adjusting the set value of the robot.

2 conceptually illustrates a distance calculation method when recognizing an indoor position by a mobile robot.

The movement path of the mobile robot 200 is limited to the indoor area 230, and two transmitters are installed in the outermost linear path (eg, a straight wall) of the mobile robot.

The mobile robot 200 transmits a position request signal in the form of a UWB signal to the first and second transmitters 210 and 220, and then rotates the first and second transmitters 210 and 220. Receives the position carrier signal in the form of a UWB signal and takes the time excluding the delayed time ΔT1 and ΔT2 in each of the first and second transmitters 210 and 220 (T1-ΔT1, T2-Δ). T2) to calculate the position from the first transmitter 210 and the second transmitter 220 to the mobile robot 200.

The distance r1 from the mobile robot to the first transmitter 210 and the distance r2 from the second transmitter 220 are respectively calculated as follows. When the propagation speed of signals transmitted and received by the mobile robot, the first transmitter 210, and the second transmitter 220 is c,

r1 = c * (T1- △ T1)

r2 = c * (T2-ΔT2).

In this case, 1 is a time required until the signal is transmitted from the mobile robot 200 to the first transmitter 210, T2 is a signal from the mobile robot 200 to the second transmitter 220 after It means the time required to receive.

To obtain the current position in the mobile robot 200, look at the equation is as shown in equation (2). At this time, (x, y, 0) is the current position of the mobile robot 200, (X1, Y1, Z1) is the position of the first transmitter 210, (X2, Y2, Z2) is the second transmitter Position 220.

(x-X1) ² + (y-Y1) ² + Z1 ² = r1 ²

(x-X2) ² + (y-Y2) ² + Z2 ² = r2 ²

Substituting Equation 1 into Equation 2,

(x-X1) ² + (y-Y1) ² + Z1 ² = (c * (T1-ΔT1)) ²

(x-X2) ² + (y-Y2) ² + Z2 ² = (c * (T2-ΔT2)) ²

In the above two equations, the position (X1, Y1, Z1) of the first transmitter 210 and the position 220 (X2, Y2, Z2) of the second transmitter are known values and are constants. Assuming that this is a flat interior, the position of the mobile robot is set to (x, y, 0).

Therefore, since it becomes a function of variables x and y, x and y can be obtained from the above two equations. Since negative y is an outdoor virtual robot position, if a positive integer is selected, the position of the robot is determined through a calculation formula.

In the position just below the transmitter (21)

x-X1 = 0

x-X2 = X1-X2 = ΔD (x-axis distance between transformers)

Since y-Y1 = y-Y2 = 0, substituting this value into Equation 2,

ΔR ² + Z1 ² = (c * (T1-ΔT1)) ²

Since the ^{2 - △ D 2 + △ R} 2 + Z2 2 = (△ T2) c * (T2)

ΔT1 = T1-

ΔT2 = T2-

Therefore, when the transmitter is installed, the distance ΔD between Z1 and Z2 and the mirror is a fixed value. Therefore, when T1 and T2 are known, ΔT1 and ΔT2 can be calculated, and the error is corrected using the calculated value. The same case can be found under the second transmitter.

3 is a diagram illustrating an internal configuration of a positioning system as a preferred embodiment of the present invention.

The mobile robot 300 includes a microcomputer 301, a UWB transmitter 302, a UWB receiver 303, a timer 304, and a memory 305. The microcomputer 301 obtains the correct? T1 and? T2 and processes the signal to calculate the position. The UWB transmitter 302 is a module in which the mobile robot 300 transmits a signal to the transmitter, and the UWB receiver 303 is a module that receives a processing result from the transmitter. The timer 304 is used to calculate the time for receiving the position carrier signal after transmitting the UWB signal, and the memory 305 stores the processing result.

The first transmitter 310 includes a UWB receiver 311, a UWB transmitter 312, an encoder 313, and a timer 314. The UWB receiver 311 receives the signal from the mobile robot 300 and transmits the result to the mobile robot 300 through the UWB transmitter 312.

The encoder 113 controls the position request signal received through the UWB receiver 311 using the timer 314 to transmit the position transfer signal from the UWB transmitter 312 after a specific time ΔT1. In this case, the specific time ΔT1 is set to a value larger than the time including the UWB reception processing time, the reception signal analysis time, and the UWB transmission processing time in the transmitter. The encoder 313 enables the position recognition since the required time is calculated without separately synchronizing between the robot and the first and second transmitters. Since the configuration and operation of the second transmitter 320 are substantially the same as those of the first transmitter 310, description thereof will be omitted.

4 shows the flow of signals between the mobile robot and the transmitter.

The control of the signal flow is managed by the robot. Since the operations and functions of the first and second transmitters are almost identical and similar, only the signal flow between the first transmitter and the robot will be described below.

Command (req, init, 410) signal for the initialization for the location recognition service req means a request, init is a signal classification for the initialization of the robot, 410 is a transmitter identification number. Upon receiving the above signal, the transmitter sends a command (resp, init, 410, OK) signal to the mobile robot to inform the mobile robot upon successful initialization of the system and enters standby mode. In the above signal, resp means response, init and 410 are the signal and identification number of the processed transmitter, and OK / NOK indicates success / failure of system initialization.

When the robot starts position recognition, it sends a signal of Command (req, start, 410) to the transmitter. Upon receiving the above signal, the transmitter switches the system to the run mode and uses the Command (resp, start, 410, OK) signal to inform the mobile robot that the preparation state is completed, and waits for a signal from the robot.

When the robot confirms the execution of the transmitter, the robot transmits a query 410, which is a position request signal, to the transmitter. Upon receiving this signal, the transmitter transmits a response 410, which is a position transfer signal, after a specified time DELTA T1. The robot calculates the time required after transmitting the response 410, which is a position transfer signal, and determines the current position based on the calculated time.

When position recognition is completed, the robot sends a command (req, sleep, 410) to the transmitter, and the transmitter informs the robot through the command (req, sleep, 410, OK). Enter The robot enters the sleep mode, for example, when it enters the charging station, when the power is turned off, or when there is no movement for a certain time.

5 is a flowchart for identifying a position in a mobile robot using a transmitter.

In order to determine the position of the robot moving in the indoor environment in which the first and second transmitters are provided, the position request signal is transmitted from the mobile robot to the first and the second transmitters, respectively (S510).

After receiving the position request signal from the mobile robot, each of the first and second transmitters delays the received signal for ΔT1 and ΔT2, respectively, and transmits the signal to the mobile robot (S520).

The mobile robot calculates each required time from transmission to reception of the first and second transmitters and receives the location of the robot based on the calculated time (S530). At this time, the method for calculating the required time and the method for determining the position of the robot based on the same will be omitted as described above with reference to FIGS. 1 and 2.

The invention can also be embodied as computer readable code on a computer readable recording medium. Computer-readable recording media include all kinds of recording devices that store data that can be read by a computer system.

Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, which are also implemented in the form of carrier waves (for example, transmission over the Internet). It also includes. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

The best embodiments have been disclosed in the drawings and specification above. Although specific terms have been used herein, they are used only for the purpose of describing the present invention and are not used to limit the scope of the present invention as defined in the meaning or claims.

Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

In the present invention, when the position of the mobile robot used indoors by using two transmitters, the installation is easy, and the cost is reduced. In addition, the effect of simplifying the system occurs by not requiring synchronization between the robot and the transmitter.

Claims (13)

A first transmitter for delaying the received signal for a preset? T1 time and transmitting the delayed signal; A second transmitter for delaying the received signal for the ΔT2 time and transmitting the delayed signal; and After transmitting a signal to each of the first and second transmitters to determine their position based on the time required to receive the signal from the first and second transmitters, respectively Positioning system comprising a; mobile robot. The method of claim 1, And the first transmitter and the second transmitter are disposed on the same straight wall surface, and the straight wall surface is located on the outermost movement path of the mobile robot. The method of claim 1, wherein the ΔT1 and ΔT2 times Positioning system, characterized in that greater than the time required to receive the signal in the first and second transmitter and the time required to transmit the signal. According to claim 1, wherein the current position in the mobile robot is calculated through the following equation, (x-X1) ² + (y-Y1) ² + Z1 ² = (c * (T1-ΔT1)) ² (x-X2) ² + (y-Y2) ² + Z2 ² = (c * (T2-ΔT2)) ² In this case, (x, y, 0) is the current position of the mobile robot, (X1, Y1, Z1) is the position of the first transmitter, (X2, Y2, Z2) is the position of the second transmitter, T1 is The time required until the signal is transmitted from the mobile robot to the first transmitter, T2 is the time required until the signal is transmitted from the mobile robot to the second transmitter, and c is the transmission speed of the signal. Positioning system, characterized in that. The method of claim 1, wherein the mobile robot and the transmitters Positioning system, characterized in that for transmitting and receiving ultra-wideband UWB signals. An apparatus for detecting a position in a mobile robot having first and second transmitters installed on the same straight wall of the outermost path that the robot can move, A transmitter for transmitting a signal to each of the first and second transmitters; A receiver which receives a signal from each of the first and second transmitters; And And a positioning unit configured to calculate a position based on each time required until the reception after transmitting the signal to each of the first and second transmitters. The method of claim 6, And the first and second transmitters transmit signals to the robot after? T1 and? T2 time after receiving the signal transmitted from the transmitter. The method of claim 7, wherein the positioning unit calculates the position through the following equation (x-X1) ² + (y-Y1) ² + Z1 ² = (c * (T1-ΔT1)) ² (x-X2) ² + (y-Y2) ² + Z2 ² = (c * (T2-ΔT2)) ² In this case, (x, y, 0) is the current position of the mobile robot, (X1, Y1, Z1) is the position of the first transmitter, (X2, Y2, Z2) is the position of the second transmitter, T1 is The time required from the transmitting unit to the first transmitter after receiving the signal, the time required from the receiving unit to receiving, T2 is the time required from the transmitting unit to the receiving unit after receiving the signal, c is Positioning mobile robot, characterized in that the transmission speed of the signal. The method of claim 6, wherein the mobile robot and the transmitters Locating mobile robot, characterized in that for transmitting and receiving UWB signals. A method of determining the position of a robot moving in an indoor environment provided with a first transmitter and a second transmitter, Transmitting a signal from a mobile robot to the first and the second transmitter; Delaying the signals received at each of the first and second transmitters for ΔT1 and ΔT2 times, respectively, and then transmitting the signals to the mobile robot; And And determining the position of the mobile robot based on each time required for transmitting the signals to the first and the second transmitters from the mobile robot to receiving the signals again. Mobile robot positioning method. The method of claim 10, And the first transmitter and the second transmitter are disposed on the same straight wall surface, and the straight wall surface is positioned on the outermost movement path of the mobile robot. The method of claim 10, wherein the current position in the mobile robot is calculated through the following equation, (x-X1) ² + (y-Y1) ² + Z1 ² = (c * (T1-ΔT1)) ² (x-X2) ² + (y-Y2) ² + Z2 ² = (c * (T2-ΔT2)) ² In this case, (x, y, 0) is the current position of the mobile robot, (X1, Y1, Z1) is the position of the first transmitter, (X2, Y2, Z2) is the position of the second transmitter, T1 is The time required until the signal is transmitted from the mobile robot to the first transmitter, T2 is the time required until the signal is transmitted from the mobile robot to the second transmitter, and c is the transmission speed of the signal. Mobile robot positioning method, characterized in that. The method of claim 10, wherein the mobile robot and the transmitters A method for locating a mobile robot, characterized by transmitting and receiving an ultra-wideband communication UWB signal.

Images