System, Method And Object For High Accuracy Magnetic Position Sensing

Abstract

Systems and methods for determining position are provided. An object produces a magnetic field having a first vector component, a second vector component, and a third vector component that are orthogonal to one another. A sensor measures a magnitude of each of the first, second, and third vector components when the object is within a range of positions. A controller is connected to the sensor and determines a relative position of the object within an undetermined cycle of a plurality of cycles based on the magnitude of the first vector component and the magnitude of the second vector component. The controller determines a cycle of the plurality of cycles in which the object is located based on the magnitude of the third vector component. The controller determines an absolute position of the object based on the relative position of the object and the cycle in which the object is located.

1 . A system for determining position, said system comprising:
 an object being configured to produce a magnetic field having a first vector component, a second vector component, and a third vector component, and with the first, second, and third vector components being orthogonal to one another;   a sensor being configured to measure a magnitude of each of the first, second, and third vector components when the object is within a range of positions; and   a controller connected to said sensor and being configured to determine a relative position of said object within an undetermined cycle of a plurality of cycles based on the magnitude of the first vector component and the magnitude of the second vector component, to determine a cycle of the plurality of cycles in which said object is located based on the magnitude of the third vector component, and wherein said controller determines an absolute position of said object based on the relative position of said object and the cycle in which said object is located.   
     
     
         2 . The system of  claim 1  wherein the magnitude of the third vector component is unique for each possible position of said object within the range of positions. 
     
     
         3 . (canceled) 
     
     
         4 . (canceled) 
     
     
         5 . The system of  claim 1  wherein said object is further configured to produce the magnetic field such that the third vector component has a slope that is substantially constant relative to position of the object within the range of positions. 
     
     
         6 . The system of  claim 5  wherein the slope of the third vector component is further defined as being monotonic. 
     
     
         7 . The system of  claim 1  wherein said object is further defined as a single magnet configured to produce the magnetic field. 
     
     
         8 . The system of  claim 1  wherein said object includes a plurality of magnets being configured to altogether produce the magnetic field. 
     
     
         9 . (canceled) 
     
     
         10 . (canceled) 
     
     
         11 . The system of  claim 1  wherein said object is further configured to move within the range of positions along a predetermined path. 
     
     
         12 . The system of  claim 11  wherein the magnitude of each of the first, second, and third vector components, as measured by said sensor, are configured to change as the object moves within the range of positions along the predetermined path. 
     
     
         13 . The system of  claim 1  wherein said controller is further configured to determine the relative position of said object based solely on the magnitude of the first vector component and the magnitude of the second vector component. 
     
     
         14 . The system of  claim 1  wherein said controller is further configured to determine the cycle in which said object is located based solely on the magnitude of the third vector component. 
     
     
         15 . (canceled) 
     
     
         16 . The system of  claim 1  wherein said controller is further configured to determine a position of a secondary object based on the absolute position of said object. 
     
     
         17 . The system of  claim 1  wherein said object is fixed to a clutch positioning component of an automated manual transmission. 
     
     
         18 . A method of operating a system for determining position with the system including an object, a sensor, and a controller connected to the sensor, and with the object being configured to move within a range of positions and to provide a magnetic field having a first vector component, a second vector component, and a third vector component and with the first, second, and third vector components being orthogonal to one another, said method comprising the steps of:
 moving the object within the range of positions;   measuring with the sensor a magnitude of each of the first, second, and third vector components when the object is within the range of positions;   determining with the controller a relative position of the object within an undetermined cycle of a plurality of cycles based on the magnitude of the first vector component and the magnitude of the second vector component;   determining with the controller a cycle of the plurality of cycles in which the object is located based on the magnitude of the third vector component; and   determining with the controller an absolute position of the object based on the relative position of the object and the cycle in which the object is located.   
     
     
         19 . The method of  claim 18  wherein the step of determining with the controller the cycle in which the object is located is further defined as retrieving with the controller from a lookup table the cycle corresponding to the magnitude of the third vector component. 
     
     
         20 . The system of  claim 18  wherein the step of determining with the controller the cycle in which the object is located is further defined as calculating with the controller the cycle as a function of the magnitude of the third vector component. 
     
     
         21 . The method of  claim 18  wherein the step of determining with the controller the relative position of the object is further defined as retrieving with the controller from a lookup table a position parameter having a tangent equal to a quotient of both the magnitude of the first vector component and the magnitude of the second vector component. 
     
     
         22 . The method of  claim 18  wherein the step of determining with the controller the relative position of the object is further defined as calculating with the controller a position parameter having a tangent equal to a quotient of both the magnitude of the first vector component and the magnitude of the second vector component. 
     
     
         23 . An object for use in position sensing, said object comprising a length and being configured to move linearly within a range of positions and being configured to produce a magnetic field having a first vector component, a second vector component, and a third vector component, and with the first, second, and third vector components being orthogonal to one another, and wherein a magnitude of the first vector component and a magnitude of the second vector component each varies cyclically along the length of the object, and wherein the magnitude of the third vector component is monotonic along the length of the object. 
     
     
         24 . The object of  claim 23  wherein said object includes a plurality of magnets being configured to altogether produce the magnetic field. 
     
     
         25 . The object of  claim 23  wherein said object is further defined as a single magnet being configured to produce the magnetic field. 
     
     
         26 . The object of  claim 23 , wherein the magnitude of the third vector component is monotonic such that the magnitude of the third vector component is unique for each position along the length of said object. 
     
     
         27 . The object of  claim 23 , wherein the magnitude of the first vector component and the magnitude of the second vector component each vary cyclically along the length of said object such that a relative position of said object is determinable within an undetermined cycle of a plurality of cycles based on the magnitude of the first vector component and the magnitude of the second vector component. 
     
     
         28 . The object of  claim 27 , wherein the magnitude of the third vector component is monotonic along the length of said object such that a cycle of the plurality of cycles in which said object is located is determinable based on the magnitude of the third vector component. 
     
     
         29 . (canceled) 
     
     
         30 . The object of  claim 23 , wherein:
 the first vector component extends radially from said object;   the second vector component extends longitudinally through said object; and   the third vector component extends radially from said object and orthogonal to both the first and second vector components.   
     
     
         31 . The object of  claim 23  wherein said object is configured to be fixed to a clutch positioning component of an automated manual transmission.