# US 11,029,698 B2 · Method for tracking movement of a mobile robotic device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,029,698 B2 - Document ID: US11029698B2 - Status: Granted - Kind: B2 - Application number: 15/955,344 - Filed: 2018-04-17 - Published: 2019-10-17 - Granted: 2021-06-08 - Earliest claimed: 2018-04-17 - Assignees: AI Incorporated - Applicants: Ali Ebrahimi Afrouzi - Inventors: Ali Ebrahimi Afrouzi - Web page: https://patentgrep.com/patent/US11029698B2 ## CPC - G05D 1/0246: {using a video camera in combination with image processing means} - G05D 1/0253: {extracting relative motion information from a plurality of images taken successively, e.g. visual odometry, optical flow (determining position or orientation from images G06T7/70)} - G05D 1/0268: {using internal positioning means} - G06T 7/20: Analysis of motion (motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51) - G05D 1/0219: {ensuring the processing of the whole working surface} - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract A method for tracking movement and turning angle of a mobile robotic device using two optoelectronic sensors positioned on the underside thereof. Digital image correlation is used to analyze images captured by the optoelectronic sensors and determine the amount of offset, and thereby amount of movement of the device. Trigonometric analysis of a triangle formed by lines between the positions of the optoelectronic sensors at different intervals may be used to determine turning angle of the mobile robotic device. ## Claims ### Claim 1 A method for tracking movement of a robotic device comprising: capturing a plurality of images of a driving surface by each of at least two optoelectronic sensors of the robotic device moving within the environment; obtaining with one or more processors of the robotic device, a plurality of images by each of the at least two optoelectronic sensors; determining, with one or more processors of the robotic device, based on images captured by each of the at least two optoelectronic sensors, linear movement of each of the at least two optoelectronic sensors from a first x, y coordinate position to a second x, y coordinate position, each position given by an x, y coordinate; and determining, with one or more processors of the robotic device, rotational movement of the robotic device based on an angle between a first and a third line of a right-handed triangle defined by: the first line connecting a first x, y coordinate position of a first optoelectronic sensor and a second x, y coordinate position of a second optoelectronic sensor; a second line extending from the second x, y coordinate position of the second optoelectronic sensor towards a line passing through the first x, y coordinate position of the first optoelectronic sensor and a first x, y coordinate position of the second optoelectronic sensor, the line being perpendicular to the second line; and the third line connecting the first x, y coordinate position of the first optoelectronic sensor to the second line, the third line being perpendicular to the second line; wherein a length of the first line is the distance between the first and the second optoelectronic sensors and a length of the second line is determined by a difference in the first and the second y coordinate position of the second optoelectronic sensor. ### Claim 2 (depends on 1) The method of claim 1, wherein linear movement of the at least two optoelectronic sensors is equal to linear movement of the robotic device. ### Claim 3 (depends on 1) The method of claim 1, wherein determining linear movement of each of the at least two optoelectronic sensors further comprises determining maximum cross correlation between successive images captured by each of the at least two optoelectronic sensors. ### Claim 4 (depends on 1) The method of claim 1, wherein the plurality of images captured by each of the at least two optoelectronic sensors overlap with preceding images captured by each of the at least two optoelectronic sensors. ### Claim 5 (depends on 1) The method of claim 1, wherein the at least two optoelectronic sensors are positioned on opposite sides of an underside of the robotic device. ### Claim 6 A robotic device comprising: a chassis including a set of wheels; a motor to drive the wheels; a battery to provide power to the robotic device; a controller in communication with the motor and wheels to steer movement of the robotic device; two or more optoelectronic sensors for capturing a plurality of images of a driving surface of the robotic device; and a processor for: obtaining the plurality of images by each of the two or more optoelectronic sensors; determining, based on images captured by each of the two or more optoelectronic sensors, linear movement of the two or more optoelectronic sensors from a first x, y coordinate position to a second x, y coordinate position, each position given by an x, y coordinate; and, rotational movement of the robotic device based on an angle between a first and a third line of a right-handed triangle defined by: the first line connecting a first x, y coordinate position of a first optoelectronic sensor and a second x, y coordinate position of a second optoelectronic sensor; a second line extending from the second x, y coordinate position of the second optoelectronic sensor towards a line passing through the first x, y coordinate position of the first optoelectronic sensor and a first x, y coordinate position of the second optoelectronic sensor, the line being perpendicular to the second line; and the third line connecting the first x, y coordinate position of the first optoelectronic sensor to the second line, the third line being perpendicular to the second line; wherein a length of the first line is the distance between the first and the second optoelectronic sensors and a length of the second line is determined by a difference in the first and the second y coordinate position of the second optoelectronic sensor. ### Claim 7 (depends on 6) The robotic device of claim 6, wherein linear movement of the two or more optoelectronic sensors is equal to linear movement of the robotic device. ### Claim 8 (depends on 6) The robotic device of claim 6, wherein determining linear movement of each of the two or more optoelectronic sensors further comprises determining maximum cross correlation between successive images captured by each of the two or more optoelectronic sensors. ### Claim 9 (depends on 6) The robotic device of claim 6, wherein the plurality of images captured by each of the two or more optoelectronic sensors overlap with preceding images captured by each of the two or more optoelectronic sensors. ### Claim 10 (depends on 6) The robotic device of claim 6, wherein the two or more optoelectronic sensors are positioned on opposite sides of an underside of the robotic device.