# US 2018/0024561 A1 · Robot and method for localizing a robot > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0024561 A1 - Document ID: US20180024561A1 - Status: Published application - Kind: A1 - Application number: 15/655,451 - Filed: 2017-07-20 - Published: 2018-01-25 - Earliest claimed: 2016-07-20 - Assignees: Singapore University of Technology and Design - Inventors: Gim Song SOH; Shaohui FOONG; Kevin OTTO; Akash VIBHUTE; Kristin WOOD - Web page: https://patentgrep.com/patent/US20180024561A1 ## CPC - G05D 1/027: {comprising intertial navigation means, e.g. azimuth detector (inertial navigation G01C21/16; inertial navigation combined with non-inertial navigation instruments G01C21/165)} - G05D 1/0272: {comprising means for registering the travel distance, e.g. revolutions of wheels (measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00)} - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES ## Abstract According to various embodiments, there is provided a robot including: a spherical shell; a cart in the spherical shell, the cart including a plurality of wheels rotatable to move the cart along an inner surface of the spherical shell; a sensor coupled to the cart, the sensor configured to provide an inertial measurement of the cart; a motion encoder configured to measure an angular velocity of each wheel of the plurality of wheels; and a localizer configured to determine a location of the robot, based on the angular velocities of the plurality of wheels and the inertial measurement of the cart. ## Claims ### Claim 1 A robot comprising: a spherical shell; a cart located in the spherical shell, the cart comprising a plurality of wheels rotatable to move the cart along an inner surface of the spherical shell; a sensor coupled to the cart, the sensor configured to provide an inertial measurement of the cart; a motion encoder configured to measure an angular velocity of each wheel of the plurality of wheels; and a localizer configured to determine a location of the robot, based on the angular velocities of the plurality of wheels and the inertial measurement of the cart. ### Claim 2 (depends on 1) The robot of claim 1, further comprising: a motion controller configured to independently control each wheel of the plurality of wheels. ### Claim 3 (depends on 1) The robot of claim 1, wherein the motion encoder comprises a plurality of wheel encoders, wherein each wheel encoder comprises a line sensor configured to generate an analog signal upon sensing a reflective surface. ### Claim 4 (depends on 3) The robot of claim 3, further comprising: an encoder filter configured to convert the analog signal into digital pulses. ### Claim 5 (depends on 4) The robot of claim 4, wherein the encoder filter is configured to convert the analog signal into digital pulses based on a differential of the analog signal. ### Claim 6 (depends on 1) The robot of claim 1, wherein the inertial measurement comprises yaw and pitch of the cart. ### Claim 7 (depends on 1) The robot of claim 1, wherein the localizer is configured to determine the location of the robot further based on an angular velocity of the spherical shell. ### Claim 8 (depends on 7) The robot of claim 7, wherein the localizer is configured to determine the angular velocity of the spherical shell based on an inner radius of the spherical shell, radius of each wheel of the plurality of wheels and angular velocities of each wheel of the plurality of wheels. ### Claim 9 (depends on 1) The robot of claim 1, wherein the cart is constantly in contact with the inner surface of the spherical shell. ### Claim 10 (depends on 1) The robot of claim 1, wherein the sensor comprises an inertial measurement unit and a moving average bandpass filter. ### Claim 11 (depends on 10) The robot of claim 10, wherein the moving average bandpass filter is configured to generate the inertial measurement based on readings from the inertial measurement unit. ### Claim 12 (depends on 1) The robot of claim 1, further comprising: a navigator configured to determine motion parameters of the spherical shell required to reach a desired location, based on the determined location. ### Claim 13 (depends on 12) The robot of claim 12, wherein the motion parameters comprise a rolling curvature of the spherical shell. ### Claim 14 (depends on 12) The robot of claim 12, wherein the navigator is configured to determine the motion parameters based on pure-pursuit algorithm. ### Claim 15 (depends on 12) The robot of claim 12, further comprising: a motion controller configured to control each wheel of the plurality of wheels based on the determined motion parameters. ### Claim 16 (depends on 1) The robot of claim 1, wherein at least one of a surface of the cart in contact with the inner surface of the spherical shell or the inner surface of the spherical shell is at least substantially rough. ### Claim 17 (depends on 1) The robot of claim 1, wherein the cart comprises a motor configured to drive the cart to overcome friction between the inner surface of the spherical shell and a surface of the cart in contact with the inner surface of the spherical shell. ### Claim 18 A method for localizing a robot comprising a cart in a spherical shell, the method comprising: obtaining an inertial measurement of the cart using a sensor coupled to the cart; measuring an angular velocity of each wheel of the cart with a motion encoder; and determining a location of the robot based on the angular velocity of each wheel and the inertial measurement of the cart.