Robot and method for localizing a robot

1. A robot, comprising:

a spherical shell less than 150 mm in diameter;

a non-holonomic cart located in the spherical shell, the non-holonomic cart comprising a plurality of wheels rotatable to move the non-holonomic cart along an inner surface of the spherical shell;

a sensor coupled to the non-holonomic cart, the sensor configured to provide an inertial measurement of the non-holonomic cart;

a motion encoder configured to measure an angular velocity of each wheel of the plurality of wheels;

a localizer configured to determine a spatial location of the robot along a trajectory, based on the measured angular velocities of the plurality of wheels and the inertial measurement of the non-holonomic cart; and

a navigator configured to determine motion parameters of the spherical shell required to reach a desired location based on the determined spatial location of the robot.

2. The robot of claim 1 , wherein the inertial measurement comprises yaw and pitch of the non-holonomic cart.

3. 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.

4. The robot of claim 3 , 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.

5. The robot of claim 1 , wherein the non-holonomic cart is constantly in contact with the inner surface of the spherical shell.

6. The robot of claim 1 , wherein the sensor comprises an inertial measurement unit and a moving average bandpass filter.

7. The robot of claim 6 , wherein the moving average bandpass filter is configured to generate the inertial measurement based on readings from the inertial measurement unit.

8. The robot of claim 1 , wherein the motion parameters comprise a rolling curvature of the spherical shell.

9. The robot of claim 1 , wherein at least one of a surface of the non-holonomic cart in contact with the inner surface of the spherical shell or the inner surface of the spherical shell is rough.

10. The robot of claim 1 , wherein the non-holonomic cart comprises a motor configured to drive the non-holonomic cart to overcome friction between the inner surface of the spherical shell and a surface of the non-holonomic cart in contact with the inner surface of the spherical shell.

11. The robot of claim 1 , wherein the navigator is configured to determine the motion parameters of the spherical shell required to reach a desired location based on the determined spatial location of the robot using pure-pursuit algorithm.

12. The robot of claim 1 , further comprising:

a motion controller configured to control each wheel of the plurality of wheels based on the determined motion parameters.

13. The robot of claim 1 ,

wherein the motion encoder comprises a plurality of wheel encoders, an analog-digital converter, and an encoder filter,

wherein each wheel encoder comprises a line sensor configured to generate an analog signal upon sensing a reflective surface,

wherein the analog-digital converter is configured to generate a raw encoder signal based on the analog signal, and

wherein the encoder filter is configured to determine rates of change in the raw encoder signal, and is further configured to generate a digital signal based on the determined rates of change.

14. The robot of claim 1 , having a mass of less than 150 grams.

15. The robot of claim 1 , wherein the localizer is configured to determine a velocity of the spherical shell based on the inertial measurement and further based on the measured angular velocities of the plurality of wheels, and wherein the localizer is configured to determine the spatial location of the robot based on the determined velocity of the spherical shell and further based on the inertial measurement.

16. A method for localizing a robot comprising a non-holonomic cart in a spherical shell, the method comprising:

obtaining an inertial measurement of the non-holonomic cart using a sensor coupled to the non-holonomic cart;

measuring an angular velocity of each wheel of the non-holonomic cart with a motion encoder, wherein the motion encoder comprises a plurality of wheel encoders, an analog-digital converter and an encoder filter, each wheel encoder comprising a line sensor;

determining a spatial location of the robot along a trajectory based on the measured angular velocity of each wheel and the inertial measurement of the non-holonomic cart; and

determining motion parameters of the spherical shell required to reach a desired location based on the determined spatial location of the robot,

wherein the spherical shell is 150 mm in diameter.