# US 7,613,544 B2 · Mobile robot, and system and method for autonomous navigation of the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,613,544 B2 - Document ID: US7613544B2 - Status: Granted - Kind: B2 - Application number: 10/753,403 - Filed: 2004-01-09 - Published: 2004-10-14 - Granted: 2009-11-03 - Earliest claimed: 2003-01-11 - Assignees: Samsung Electronics Co., Ltd. - Inventors: Dong-ryeol Park; Seok-won Bang - Web page: https://patentgrep.com/patent/US7613544B2 ## CPC - G05D 1/0234: {using optical markers or beacons (optical beacons per se G01S1/70)} - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES ## Abstract Disclosed herein is a mobile robot, and system and method for autonomous navigation of the same. The mobile robot includes a communications module for transmitting a light source control signal to selectively control light sources of a landmark array to flicker, an image processing module for calculating image coordinates of the light sources from an image signal, a pose calculation module for calculating position coordinates of the mobile robot, a motion control module for calculating a moving path and controlling the mobile robot to move along the moving path, and a main control module for controlling interoperations of the modules and general operations of the mobile robot. ## Claims ### Claim 1 A mobile robot, comprising: a communications module for transmitting a light source control signal to selectively control flickering of each of a plurality of light sources of a landmark array provided in a working space such that each of said plurality of light sources can be separately detected by its flickering; an image processing module for calculating image coordinates of at least one of the plurality of the light sources by separately detecting the at least one light source by selectively controlling the flickering the light source, controlled to flicker in response to the light source control signal, from an image signal obtained by a camera; a pose calculation module for calculating world position coordinates of the mobile robot in the working space using the calculated image coordinates and previously stored world coordinates of the light sources; a motion control module for calculating a moving path in the working space for the mobile robot by applying the position coordinates of the mobile robot to previously stored spatial coordinates of the working space and controlling the mobile robot to move along the moving path in the working space; and a main control module for controlling interoperations of the communications, image processing, pose calculation and motion control modules of the mobile robot. ### Claim 2 (depends on 1) The mobile robot as set forth in claim 1, further comprising a memory module for storing the world coordinates of the light sources, spatial coordinates of the mobile robot in the working space, and parameters calculated through camera calibration for compensating for distortion of a lens of the camera. ### Claim 3 (depends on 1) The mobile robot as set forth in claim 1, wherein the pose calculation module calculates translation and rotation of the robot by applying the image coordinates and the world coordinates to a position calculation algorithm. ### Claim 4 (depends on 3) The mobile robot as set forth in claim 3, wherein the pose calculation algorithm is a certain transformation matrix equation that is obtained by constructing an extension model for obtaining a translation and a rotation of the camera using a world coordinate system and a camera coordinate system and applying the extension model to a formula for compensating for distortion caused by a lens of the camera. ### Claim 5 A system for autonomous navigation of a mobile robot, comprising: a landmark array comprising a plurality of light sources disposed in a working space to selectively flicker; a landmark array control module for separately controlling each of the light sources of the plurality of light sources of the landmark array to flicker; and a mobile robot equipped with a pose calculation module for selectively controlling each of the light sources in the plurality of light sources of the landmark array to flicker such that each of said plurality of light sources can be separately detected by transmitting a light source control signal to the landmark array control module and recognizing a world position of the mobile robot in a working space using image coordinates of detected light sources, controlled to flicker in response to the light source control signal, extracted from an image signal. ### Claim 6 (depends on 5) The system as set forth in claim 5, wherein the light sources are light emitting devices, including electro-luminescent devices and light emitting diodes, which emit light with a certain wavelength and a certain brightness. ### Claim 7 (depends on 5) The system as set forth in claim 5, wherein the light sources are each assigned with position information comprised of a specific identification number and world coordinates in the working space in which the landmark array is arranged. ### Claim 8 (depends on 5) The system as set forth in claim 5, wherein the landmark array control module comprises: an access point for receiving and processing the light source control signal transmitted from the mobile robot; and a light source control unit for controlling corresponding light sources to flicker in response to the light source control signal input from the access point. ### Claim 9 (depends on 8) The system as set forth in claim 8, wherein the communications module and the access point are assigned with frequencies of a high bandwidth and transmit/receive data via the assigned frequencies, or the communications module and the access point transmit/receive the light source control signal through infrared data communications using infrared radiation or through data communications based on wireless communications protocols. ### Claim 10 (depends on 5) The system as set forth in claim 5, wherein the pose calculation module calculates translation and rotation of the robot by applying image coordinates and world coordinates to a certain pose calculation algorithm. ### Claim 11 (depends on 10) The system as set forth in claim 10, wherein the pose calculation algorithm is a certain transformation matrix equation that is obtained by constructing an extension model for obtaining a translation and a rotation of the camera using a world coordinate system and a image coordinate system, and applying the extension model to a formula for compensating for distortion caused by a lens of the camera. ### Claim 12 (depends on 10) The system as set forth in claim 10, wherein the communications module and the access point are assigned with frequencies of a high bandwidth and transmit/receive data via the assigned frequencies, or the communications module and the access point transmit/receive the light source control signal through infrared data communications using infrared radiation or through data communications based on wireless communications protocols. ### Claim 13 (depends on 5) The system as set forth in claim 5, wherein the mobile robot comprises: a main control module for controlling an entire operation for pose recognition and moving according to an operation management algorithm for autonomous navigation of the mobile robot; a communications module for transmitting the light source control signal to control light sources of the landmark array under control of the main control unit; an image processing module for detecting feature points of the light source, controlled to flicker through the communications module, from the image signal obtained by the camera; a motion control module for controlling the mobile robot to move under control of the main control module; and a memory module for storing parameters calculated through camera calibration for compensating for distortion caused by a lens of the camera, world coordinates of the light sources, and spatial coordinates of the mobile robot in the working space. ### Claim 14 (depends on 13) The system as set forth in claim 13, wherein the image processing module comprises; a camera equipped with a filter for filtering the wavelength of the light source from the image signal obtained by the camera; and a signal processing unit for detecting the wavelength of the light source from the filtered image signal output by the camera. ### Claim 15 A method for autonomous navigation of a mobile robot, comprising the steps of: (1) the mobile robot selectively controlling each of a plurality of light sources of a landmark array arranged across a certain working space to flicker by transmitting a light source control signal to the landmark array such that each of the light sources can be separately detected; (2) extracting image coordinates of at least one of the plurality of the light sources by detecting a light source by the selectively controlled flickering the light source, controlled to flicker in response to the light source control signal, from an image signal input from a camera; and (3) calculating a current world position of the mobile robot with reference to the extracted image coordinates and previously stored world coordinates of the detected light source. ### Claim 16 (depends on 15) The method as set forth in claim 15, further comprising: (4) a motion control module determining a moving path to a destination using the calculated current position and controlling the mobile robot to move along the determined moving path. ### Claim 17 (depends on 15) The method as set forth in claim 15, wherein the first step comprises the steps of: transmitting a light source control signal to a landmark array control module to control a specified one of the light sources of the landmark array to flicker; and the landmark array control module controlling the specified light source to flicker in response to the light source control signal. ### Claim 18 (depends on 15) The method as set forth in claim 15, wherein the second step comprises the steps of: detecting feature points of the light source from the image signal input from the camera; determining whether the light source is detected by the camera using the feature points of the light source; searching for the light source detected by the camera by sequentially controlling light sources near a previously tried light source to flicker if the previously tried light source is not detected; and extracting image coordinates of a detected light source from the image signal if any light source is detected. ### Claim 19 (depends on 15) The method as set forth in claim 15, wherein the third step comprises the steps of: detecting position information of the detected light source; calculating the pose of the mobile robot with reference to the calculated position of the mobile robot; and ascertaining a precise position of the mobile robot by matching the calculated position of the mobile robot with spatial coordinate information of the working space previously stored in the mobile robot. ### Claim 20 (depends on 15) The method as set forth in claim 15, wherein the mobile robot detects two or more light sources by repeating the first and second steps so as to precisely ascertain the position of the mobile robot.