Systems, methods, and apparatus for calibration of and three-dimensional tracking of intermittent motion with an inertial measurement unit
First Claim
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1. A system for calibrating an inertial measurement unit (IMU) that has one or more sensors, said system comprising:
- a calibration fixture, said calibration fixture having a support surface and a first rail, the support surface having a planar surface and the first rail having a planar surface, the planar surface of the first rail being orthogonal to the planar surface of the support surface to provide physical limits to a relative movement of the IMU in a linear or rotational direction with respect to said calibration fixture, said calibration fixture being configured to allow for linear movement of the IMU along the first rail of said calibration fixture and within the physical limits of said calibration fixture, and said calibration fixture being configured to allow for angular positioning of the IMU at various angles relative to and within the physical limits of said calibration fixture; and
a computer system in functional communication with the IMU, the computer system comprising;
a processor; and
one or more physical non-transitory computer readable medium having computer executable instructions stored thereon that when executed by the processor, cause the computer system to perform the following;
receiving signals from the one or more sensors in response to linear or rotational movement of the IMU with respect to and within the physical limits of said calibration fixture,calculating calibration values to compensate for signals from the one or more sensors from a calibration model.
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Abstract
Generally, implementations of the present invention include devices, systems, and methods for tracking intermittent motion. Such systems can be used to calibrate inertial measurement units (IMUs), which can be used to obtain acceleration, linear and angular velocities, orientation, and position of a moving body. Such systems also can be used to account and compensate for errors and imperfections present in an IMU prior to and during operation.
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Citations
23 Claims
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1. A system for calibrating an inertial measurement unit (IMU) that has one or more sensors, said system comprising:
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a calibration fixture, said calibration fixture having a support surface and a first rail, the support surface having a planar surface and the first rail having a planar surface, the planar surface of the first rail being orthogonal to the planar surface of the support surface to provide physical limits to a relative movement of the IMU in a linear or rotational direction with respect to said calibration fixture, said calibration fixture being configured to allow for linear movement of the IMU along the first rail of said calibration fixture and within the physical limits of said calibration fixture, and said calibration fixture being configured to allow for angular positioning of the IMU at various angles relative to and within the physical limits of said calibration fixture; and a computer system in functional communication with the IMU, the computer system comprising; a processor; and one or more physical non-transitory computer readable medium having computer executable instructions stored thereon that when executed by the processor, cause the computer system to perform the following; receiving signals from the one or more sensors in response to linear or rotational movement of the IMU with respect to and within the physical limits of said calibration fixture, calculating calibration values to compensate for signals from the one or more sensors from a calibration model. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A system for estimating a state of an IMU that has one or more accelerometers and one or more gyroscopes, said system comprising:
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an IMU having one or more accelerometers and one or more gyroscopes, the one or more accelerometers and one or more gyroscopes each having a known noise band; and a computer system functionally connected to the IMU, the computer system comprising; a processor; and one or more physical non-transitory computer readable medium having computer executable instructions stored thereon that, when executed by the processor, cause the computer system to perform the following; receiving a first signal from the one or more accelerometers and a second signal from the one or more gyroscopes and applying one or more calibration values to correct for one or more of misalignment of the one or more accelerometers and one or more gyroscopes relative to a reference frame, a linear or nonlinear scale factor, an anisotropic sensitivity, a bias, a gyroscope acceleration sensitivity, and temperature sensitivity, monitoring the first signal to determine whether said first signal is within the noise band of the one or more gyroscopes and monitoring the second signal to determine whether said second signal is within the noise band of the one or more accelerometers that sent said second signal, and if said received first signal and said received second signal are within noise bands of the respective one or more gyroscopes and one or more accelerometers that sent said received first signal and said received second signal, assigning a status of zero velocity to the IMU. - View Dependent Claims (15, 16, 17)
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18. A system for tracking intermittent motion, comprising:
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an inertial measurement unit (IMU) that has one or more accelerometers and one or more gyroscopes; and a calibration fixture, said calibration fixture having a support surface, a first rail, and a second rail, the support surface, the first rail, and the second rail being orthogonal to each other to provide physical limits to a relative movement of the IMU in a linear or rotational direction with respect to said calibration fixture, said calibration fixture being configured to allow for linear movement of the IMU along the first rail or the second rail of said calibration fixture, and said calibration fixture being configured to allow for angular positioning of the IMU at various angles relative to and within the physical limits of said calibration fixture; a moveable support block having a first surface, a second surface, and a third surface, the first surface, the second surface, and the third surface of the moveable support block being orthogonal to each other, the IMU is sized and configured to be secured to the moveable support block and moved within the calibration fixture; a computer system functionally connected to the IMU, the computer system comprising; a processor; and one or more physical non-transitory computer readable medium having computer executable instructions stored thereon that when executed by the processor, cause the computer system to perform the following; receiving signals from the one or more accelerometers and one or more gyroscopes as the IMU is moved along the first rail or the second rail, estimating a state of the IMU, if the IMU is in a zero velocity state, updating calibration values of biases for the one or more gyroscopes and update calibration values of biases for the one or more accelerometers, if the IMU is not in a zero velocity state, processing the signal received from the IMU by applying one or more calibration values to correct for one or more of misalignment of the one or more accelerometers and one or more gyroscopes relative to a reference frame, a linear or nonlinear scale factor, an anisotropic sensitivity, a bias, a gyroscope acceleration sensitivity, and temperature sensitivity to obtain one or more of specific force, acceleration, angular velocity, linear velocity, linear displacement, and orientation of the IMU; and an output module configured to output one or more measurements and/or estimates. - View Dependent Claims (19, 20, 21, 22, 23)
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Specification