Method and device for detecting a substantially invariant rotation axis
AssigneesCommissariat a l'Energie Atomique, Universite Joseph Fourier, Institut National Polytechnique de Grenoble
InventorsChristelle Godin, Stèphane Bonnet, Alain Barraud, Suzanne Lesecq
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Abstract
A method for detecting a substantially invariant rotation axis of a motion of a mobile body equipped with at least one inertial or magnetic sensor with three sensitive axes that includes acquiring physical measurements with respect to the three sensitive axes of the sensor, the physical measurements including at least three samples at different times, estimating a substantially invariant rotation axis in the physical measurements space, and identifying the estimated axis as the substantially invariant rotation axis of the motion. In one aspect, the method is applicable for estimating the motion of a mobile body rotating about a substantially invariant axis.
Claims16
A method for detecting a substantially invariant rotation axis of a motion of a mobile body equipped with one of an inertial or magnetic sensor with three sensitive axes, the method comprising the following steps:
- acquiring physical measurements with respect to the three sensitive axes by the inertial or magnetic sensor, the physical measurements comprising at least three samples at different times during motion of the mobile body;
- estimating from the at least three samples a substantially invariant rotation axis in the physical measurements space;
- and
- identifying the estimated substantially invariant rotation axis as the substantially invariant rotation axis of the motion.
A method for detecting a substantially invariant rotation axis of a motion of a mobile body equipped with one of an inertial or magnetic sensor with three sensitive axes, the method comprising the following steps:
- acquiring physical measurements with respect to the three sensitive axes by the inertial or magnetic sensor, the physical measurements comprising at least three samples at different times during motion of the mobile body:
- estimation from the at least three samples a substantially invariant rotation axis in the physical measurement space;
- and
- identifying the estimated substantially invariant rotation axis as the substantially invariant rotation axis of the motion;
- and
- transforming coordinates of the estimated substantially invariant rotation axis in a measurement frame of reference of the inertial or magnetic sensor into coordinates in a geophysical frame of reference.
A method for detecting a substantially invariant rotation axis of a motion of a mobile body, wherein the mobile body is equipped with a magnetometer having three sensitive axes and an accelerometer having three sensitive axes, the method comprising the following steps:
- acquiring physical measurements with respect to the three sensitive axes by the magnetometer and the accelerometer, respectively, the physical measurements comprising at least three samples at different times during motion of the mobile body;
- estimating from the at least three samples a substantially invariant rotation axes in the physical measurements spaces of said magnetometer and said accelerometer, respectively;
- and
- validating the substantially invariant rotation axis of the motion of a linear combination of the estimated rotation axes for said physical measurements from the magnetometer and from the accelerometer, wherein coefficients of the combination are not limited between 0 and 1, their sum being equal to 1, and wherein the coefficients are a function of the values of the indicators of the variations of the rotation axes of the magnetometer or the accelerometer, or both.
A device for detecting a substantially invariant rotation axis of a motion of a mobile body equipped with one of an inertial or magnetic sensor with three sensitive axes, wherein the device comprises:
- a sensor acquiring physical measurements with respect to the three sensitive axes of the inertial or magnetic sensor, the physical measurements comprising at least three samples at different times during motion of the mobile body;
- means for estimating from the at least three samples a substantially invariant rotation axis in the physical measurements space;
- and
- means for identifying the estimated substantially invariant rotation axis as the substantially invariant rotation axis of the motion.
Dependencies are inferred from the claim text.