Gyroscope and optical flow sensor scale calibration
A method for calculating a scale factor for a gyroscope can include detecting, by a gyroscope, a physical motion of a robot, detecting, by an optical flow (OF) sensor (and/or camera), one or more image signals including information; and deriving estimates of sensor calibration parameters based on the detected physical motion and the information.
1 . A method for calibrating a gyroscope located on a robot, the method comprising:
detecting, by the gyroscope, a physical motion of the robot operating on a surface;
detecting, by an optical flow (OF) sensor, one or more image signals including information, wherein the OF sensor detects features of the surface;
deriving estimates of sensor calibration parameters of each of the gyroscope and the OF sensor based on the detected physical motion of the robot and the information; and
calibrating the gyroscope based on the information and/or the estimates of sensor calibration parameters.
2 . The method of claim 1 , wherein the information includes a function of a respective image at each frame of the one or more image signals.
3 . The method of claim 2 , wherein the function is associated with an image quality and/or image brightness.
4 . The method of claim 1 , wherein calibrating the gyroscope comprises:
identifying a relationship between the information and the detected physical motion; and
calibrating a scale parameter of the gyroscope based on the identified relationship.
5 . The method of claim 1 , wherein the physical motion of the robot is an in-place rotation and/or a rotation more than 360 degrees.
6 . The method of claim 1 , wherein the physical motion of the robot is detected on an arbitrary surface or a surface having an unknown surface pattern.
7 . The method of claim 1 , wherein the one or more image signals are periodic signals.
8 . The method of claim 1 , further comprising:
estimating an angular motion of the robot with respect to the surface based on the information; and
calibrating the scale of the gyroscope based on the estimated angular motion.
9 . The method of claim 1 , further comprising:
relating an angular velocity to a linear velocity at the OF sensor based on a known robot geometry; and
computing a displacement scale of the OF sensor.
10 . A system to calibrate a gyroscope located on a robot, the system comprising:
the gyroscope configured to detect a physical motion of the robot operating on a surface;
an optical flow (OF) sensor configured to generate one or more image signals including information, wherein the OF sensor detects features of the surface; and
a processor configured to:
derive estimates of sensor calibration parameters of each of the gyroscope and the OF sensor based on the detected physical motion of the robot and the information; and
calibrate the gyroscope based on the information and/or the estimates of sensor calibration parameters.
11 . The system of claim 10 , wherein the information includes a function of a respective image at each frame of the one or more image signals.
12 . The system of claim 11 , wherein the function is associated with an image quality and/or image brightness.
13 . The system of claim 10 , wherein the processor is further configured to calibrate the gyroscope by:
identifying a relationship between the information and the detected physical motion; and
calibrating a scale parameter of the gyroscope based on the identified relationship.
14 . The system of claim 10 , wherein the physical motion of the robot is an in-place rotation and/or a rotation more than 360 degrees.
15 . The system of claim 10 , wherein the physical motion of the robot is detected on an arbitrary surface or a surface having an unknown surface pattern.
16 . The system of claim 10 , wherein the one or more image signals are periodic signals.
17 . The system of claim 10 , wherein the processor is further configured to:
estimate an angular motion of the robot with respect to the surface based on the information; and
calibrate the scale of the gyroscope based on the estimated angular motion.
18 . The system of claim 10 , wherein the processor is further configured to:
relate an angular velocity to a linear velocity at the OF sensor based on a known robot geometry; and
compute a displacement scale of the OF sensor.