Position sensing system
원문보기
IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0778491
(2014-03-19)
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등록번호 |
US-10260904
(2019-04-16)
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국제출원번호 |
PCT/US2014/031250
(2014-03-19)
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국제공개번호 |
WO2014/153422
(2014-09-25)
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발명자
/ 주소 |
- Rajamani, Rajesh
- Taghvaeeyan, Saber
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출원인 / 주소 |
- Regents of the University of Minnesota
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대리인 / 주소 |
Dicke, Billig & Czaja, PLLC
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인용정보 |
피인용 횟수 :
0 인용 특허 :
7 |
초록
▼
A position sensing system for measuring a position of a moving object includes a first magnetic sensor configured to measure an intensity of a magnetic field produced by the moving object. The system includes a controller configured to estimate a position of the moving object based on a nonlinear mo
A position sensing system for measuring a position of a moving object includes a first magnetic sensor configured to measure an intensity of a magnetic field produced by the moving object. The system includes a controller configured to estimate a position of the moving object based on a nonlinear model of the magnetic field produced by the moving object as a function of position around the moving object, and based on the measured intensity of the magnetic field produced by the moving object.
대표청구항
▼
1. A position sensing system for measuring a linear position of a linearly moving object, comprising: first and second magnetic sensors located near the moving object and configured to measure an intensity of a magnetic field produced by the moving object, wherein the first magnetic sensor is locate
1. A position sensing system for measuring a linear position of a linearly moving object, comprising: first and second magnetic sensors located near the moving object and configured to measure an intensity of a magnetic field produced by the moving object, wherein the first magnetic sensor is located at a known distance from the second magnetic sensor;a memory storing a nonlinear model of the magnetic field produced by the moving object as a function of position around the moving object; anda controller with an auto-calibration system configured to use an expected relationship between signals of the first and second magnetic sensors to automatically calibrate parameters of the nonlinear model and compute the linear position of the linearly moving object. 2. The position sensing system of claim 1, wherein the nonlinear model varies based on a shape of the moving object and a strength of magnetization of the moving object. 3. The position sensing system of claim 1, wherein the controller is configured to subtract an initially measured magnetic field from the measured intensity of the magnetic field produced by the moving object to remove an influence of static or slowly varying magnetic fields. 4. The position sensing system of claim 1, wherein the first and second magnetic sensors are in a fixed position and do not move with the moving object. 5. The position sensing system of claim 4, wherein the first and second magnetic sensors are aligned with an axis of linear movement of the moving object. 6. The position sensing system of claim 1, wherein the controller is configured to provide a real-time indication of a current position of the moving object. 7. The position sensing system of claim 1, and further comprising: at least one additional magnetic sensor configured to measure an intensity of the magnetic field produced by the moving object, wherein the at least one additional magnetic sensor is located at a fixed distance from the first and second magnetic sensors, and wherein the controller with the auto-calibration system is configured to use an expected relationship between signals of the first and second magnetic sensors and the at least one additional magnetic sensor to automatically calibrate parameters of the nonlinear model and compute the position of the moving object. 8. The position sensing system of claim 1, wherein the controller is configured to adaptively estimate the parameters of the nonlinear model using magnetic field measurements from the first and second magnetic sensors. 9. The position sensing system of claim 8, wherein the controller is configured to adaptively estimate the parameters based on the known distance between the first and second magnetic sensors and a known minimum and maximum distance of the moving object from the first and second magnetic sensors. 10. The position sensing system of claim 8, wherein the controller is configured to use one of a deterministic nonlinear observer and a stochastic filter to adaptively estimate parameters of the nonlinear model. 11. The position sensing system of claim 8, wherein the controller is configured to periodically update the parameters of the nonlinear model during operation of the system. 12. The position sensing system of claim 8, wherein the controller is configured to use an iterated least squares method to adaptively estimate parameters of the nonlinear model. 13. The position sensing system of claim 8, wherein the controller is configured to automatically compensate for unexpected magnetic field disturbances in the measured intensity of the magnetic field produced by the moving object. 14. The position sensing system of claim 13, wherein the controller is configured to impose at least one constraint on disturbance components read by the magnetic sensors based on a geometry and location of the magnetic sensors, and wherein the controller is configured to use the nonlinear model and the at least one constraint to estimate the disturbances. 15. The position sensing system of claim 13, wherein additional magnetic sensors located at known distances from the first and second magnetic sensors are used to estimate and compensate for the unexpected magnetic field disturbances. 16. The position sensing system of claim 1, wherein the moving object comprises a piston with linear motion inside a cylinder, and wherein the first and second magnetic sensors are positioned outside the cylinder. 17. The position sensing system of claim 1, wherein the moving object comprises a rotating object inside a machine, and wherein the first and second magnetic sensors are positioned on a static portion of the machine outside the rotating object. 18. A method of measuring a linear position of a linearly moving object, comprising: measuring an intensity of a magnetic field produced by the linearly moving object with at least one magnetic sensor located near the linearly moving object;estimating, with a controller, a linear position of the linearly moving object based on a nonlinear model of the magnetic field produced by the linearly moving object as a function of position around the linearly moving object, and based on the measured intensity of the magnetic field produced by the linearly moving object; andautomatically compensating, with the controller, for unexpected magnetic field disturbances in the measured intensity of the magnetic field based on a geometry and location of the at least one magnetic sensor. 19. The method of claim 18, wherein the nonlinear model varies based on a shape of the moving object and a strength of magnetization of the moving object. 20. The method of claim 18, and further comprising: adaptively estimating parameters of the nonlinear model using magnetic field measurements from the at least one magnetic sensor. 21. A position sensing system for measuring a linear position of a piston moving linearly within a cylinder, comprising: a plurality of magnetic sensors positioned outside of the cylinder and configured to perform magnetic field measurements of a magnetic field produced by at least one of the piston and a piston rod attached to the piston; anda controller communicatively coupled to the plurality of magnetic sensors and configured to adaptively estimate parameters of a nonlinear model of the magnetic field as a function of position around the piston using the magnetic field measurements and a known distance between the magnetic sensors, and estimate a linear position of the piston based on the nonlinear model and the magnetic field measurements. 22. The position sensing system of claim 21, wherein the controller is configured to automatically compensate for unexpected magnetic field disturbances in the magnetic field measurements based on a geometry and location of the magnetic sensors.
이 특허에 인용된 특허 (7)
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Kouno, Tsutomu, Distance-measuring system using orthogonal magnetic field generators and orthogonal magnetic field sensors.
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Fox, Joshua, Extended smart position sensing range using electromagnetics.
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Lienau Jeffrey A. (Huntsville AL), Magnet position sensing system.
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Fujiwara Yoshiro (Kawasaki JPX) Endo Michiko (Yokohama JPX) Kojima Yuji (Chigasaki JPX) Wakatsuki Noboru (Kawasaki JPX) Hirano Akira (Sagamihara JPX) Komenou Kazunari (Atsugi JPX), Position detecting apparatus using a magnetic sensor and a closed magnetic circuit with non-uniform magnetic flux distri.
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Ricks,Lamar F.; Furio,Ryan R.; Nicol,Andrew, Position detection apparatus and method for linear and rotary sensing applications.
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Krahn Donald R. (Eagan MN), Position detection apparatus including a circuit for receiving a plurality of output signal values and fitting the outpu.
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Goetz Jay R. ; Rhodes Michael L., Position detection apparatus with correction for non-linear sensor regions.
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