Optimal scan sequence for RF magnetic digitizers
First Claim
1. A method of operating a position measuring device having a sensor grid that includes a first array of sensing elements, the first array being responsive to a moveable transmitter for having a detectable signal induced therein, comprising the steps of:
- determining an expected position of the transmitter relative to the first array of sensing elements;
selecting, based on the expected position, a first sensing element and a second sensing element from the first array, the first and the second sensing elements being selected such that, based on the measurement of the first and the second sensing elements, one or more additional sensing elements may selected for further measurements;
measuring the signal induced within the first and the second sensing elements;
comparing the measured signal of the first sensing element to the measured signal of the second sensing element; and
based on an outcome of the step of comparing, selecting one or more additional sensing elements from the first array to make a further measurement.
1 Assignment
0 Petitions
Accused Products
Abstract
A sensor grid system (10), and a method of operating a sensor grid system, having a first array of inductors (14a) and a second array of inductors (14b). The first and the second arrays are each responsive to a moveable coil (18) that transmits an electromagnetic signal for having a detectable signal induced therein. The method includes a first step of determining an expected position of the coil relative to an array of inductors. A next step selects a pair of inductors that are located near to the expected position. A third step measures the signals induced into the pair of inductors, and a fourth step, based on the measurement step, determines any additional inductors from which measurements are required to interpolate the actual position of the coil. A fifth step measures the signals induced into the determined ones of the additional inductors, and a sixth step computes and reports the actual position of the coil based on the results of the first and the second steps of measuring.
-
Citations
29 Claims
-
1. A method of operating a position measuring device having a sensor grid that includes a first array of sensing elements, the first array being responsive to a moveable transmitter for having a detectable signal induced therein, comprising the steps of:
-
determining an expected position of the transmitter relative to the first array of sensing elements; selecting, based on the expected position, a first sensing element and a second sensing element from the first array, the first and the second sensing elements being selected such that, based on the measurement of the first and the second sensing elements, one or more additional sensing elements may selected for further measurements; measuring the signal induced within the first and the second sensing elements; comparing the measured signal of the first sensing element to the measured signal of the second sensing element; and based on an outcome of the step of comparing, selecting one or more additional sensing elements from the first array to make a further measurement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 29)
-
-
9. A method of operating a sensor grid having a first array of inductors and a second array of inductors, the second array being disposed orthogonally to the first array, the first and the second arrays each being responsive to a moveable transmitter for having a detectable signal induced therein, comprising the steps of:
-
determining an expected position of the transmitter relative to a first one and to a second one of the arrays of inductors; selecting at least one first inductor from the first array, the at least one first inductor being selected to be near to the expected position; measuring the signal induced within the at least one first inductor of the first array; during the step of measuring, selecting at least one first inductor from the second array, the at least one first inductor of the second array being selected to be near to the expected position; measuring the signal induced within the at least one first inductor of the second array; during the second step of measuring, examining the measured signal of the first inductor of the first array; based on an outcome of the step of examining, selecting one or more additional inductors from the first array to make at least one further measurement so as to obtain a minimum required set of measurements to perform a transmitter position calculation;
measuring the signal induced within the one or more additional inductors of the first array;during the third step of measuring, examining the measured signal of the first inductor of the second array; based on an outcome of the second step of examining, selecting one or more additional inductors from the second array to make at least one further measurement so as to obtain a minimum required set of measurements to perform a transmitter position calculation; measuring the signal induced within the one or more additional inductors of the second array; and at the completion of the fourth step of measuring, estimating a position of the transmitter, relative to the first array and the second array, based upon the signal measurements of the selected inductors of first array and of the second array.
-
-
10. A method of operating a sensor grid having a first array of differentially connected coil pairs and a second array of differentially connected coil pairs, the second array being disposed at a predetermined orientation to the first array, the first and the second arrays each being inductively coupled to a moveable coil and responsive to the moveable coil for having a detectable signal induced therein, comprising the steps of:
-
determining an expected position of the moveable coil relative to a first one of the arrays of inductors; selecting a first differentially connected coil pair from the first array, the first differentially connected coil pair being selected so as to encompass the expected position; measuring the signal induced within the first differentially connect coil pair; determining if the measured signal is positive or negative; and based on an outcome of the step of determining, selecting one or more additional differentially connected coil pairs to make further measurements. - View Dependent Claims (11, 12)
-
-
13. An electromagnetic digitizer system comprising:
-
a sensor grid having a first array of inductors and a second array of inductors, the second array being disposed at a predetermined orientation to the first array, the first and the second arrays each being responsive to a moveable coil for having a detectable signal induced therein; control means for interpolating a position of the moveable inductance relative to the first and the second arrays of inductors; said control means including means for selecting a first inductor and a second inductor from the first array, the first and the second inductors being selected so that they are disposed on opposite sides of the interpolated position; means, having an input coupled to the first array, for coupling the selected first and second inductors to an input of means for measuring the signal induced within the first and the second inductors; and means for comparing the measured signal of the first inductor to the measured signal of the second inductor; wherein said control means is responsive to an output of said comparing means for selecting one or more additional inductors from the first array to make a further measurement. - View Dependent Claims (14, 15, 16)
-
-
17. A method of operating a sensor grid having a first array of inductors and a second array of inductors, the second array being disposed at a predetermined orientation to the first array, the first and the second arrays each being responsive to a moveable transmitter for having a detectable signal induced therein, comprising the steps of:
-
estimating an expected position of the transmitter relative to a first one of the arrays of inductors; selecting at least one inductor from the first array so as to refine the estimate of the expected position, the at least one selected inductor being disposed near to the expected position; measuring the signal induced within the at least one selected inductor; before the result of the measurement is available, selecting and measuring at least one additional inductor from the first array or from the second array; when the measurement of the signal induced within the at least one selected inductor is available, examining the measured signal; based on an outcome of the step of examining, selecting at least one further inductor from the first array to make a further measurement; and estimating the actual position based on the measurement of the at least one selected inductor and the at least one further inductor. - View Dependent Claims (18)
-
-
19. A method of operating a digitizer system of a type having an array of inductors responsive to a position of a moveable field generating means, means for measuring a signal induced into any one of the inductors by the field generating means, means for controlling selection of inductors for measurement, and means for computing an interpolated position of the field generating means based on measurements made of a plurality of the inductors, comprising the steps of:
-
determining an expected position of the field generating means relative to the array of inductors;
selecting a pair of inductors that are located relative to the expected position such that a signal induced into one of the inductors, due to a difference between an actual position of the field generating means and the expected position, will be greater than or less than a signal induced into the other one of the inductors;measuring the signals induced into the inductors of the pair of inductors; based on the measurement, determining any additional inductors from which measurements are required to compute the actual position of the field generating means; measuring the signals induced into the determined ones of the additional inductors; and determining and reporting the actual position of the field generating means based on the results of the first and the second steps of measuring. - View Dependent Claims (20, 21)
-
-
22. A method of operating a digitizer system of a type having an array of inductors responsive to a position of a moveable field generating means, means for measuring both a signal magnitude and signal polarity induced into any one of the inductors by the field generating means, means for controlling selection of inductors for measurement, and means for computing an interpolated position of the field generating means based on measurements made of a plurality of the inductors, comprising the steps of:
-
determining an expected position of the field generating means relative to the array of inductors; selecting a first inductor that is located relative to the expected position such that a polarity of a signal induced into the first inductor, due to a difference between an actual position of the field generating means and the expected position, may be positive or negative; measuring the signal magnitude and polarity induced into the first inductor;
based on the measurement, determining any additional inductors from which measurements are required to compute the actual position of the field generating means;measuring the signals induced into the determined ones of the additional inductors; and computing and reporting the actual position of the field generating means based on the results of the first and the second steps of measuring.
-
-
23. A method of operating a digitizer device, said device comprising an array of sensing elements responsive to a position of a transmitting element, comprising the steps of:
-
determining an expected position of the transmitting element relative to the array of sensing elements; based on the expected position, selecting a first group comprised of one or more sensing elements for making an initial measurement, from which additional sensing elements for measurement are selected;
measuring a signal from the first group of sensing elements;based on a result of the step of measuring, determining one or more additional sensing elements from which measurements are required to determine an actual position of the transmitting element; measuring a signal from the one or more additional sensing elements; and estimating the actual position of the transmitting element relative to the array of sensing elements based on the results of the first and the second steps of measuring. - View Dependent Claims (24, 25)
-
-
26. A digitizer device comprising:
-
an array of sensing elements responsive to a position of a transmitting element; means, having an input coupled to an output of said array, for determining an expected position of the transmitting element relative to the array of sensing elements; means, responsive to the expected position, for selecting a first group comprised of one or more sensing elements for making an initial measurement; and means for measuring the signals from the first group of sensing elements;
whereinsaid selecting means is responsive to the operation of said measuring means for selecting one or more additional sensing elements that are required to be measured to determine an actual position of the transmitting element;
whereinsaid measuring means measures the one or more additional sensing elements; and
further includingmeans for estimating the actual position of the transmitting element relative to the array of sensing elements based on the results of the measuring means measuring the first group of sensing elements and the one or more additional sensing elements. - View Dependent Claims (27, 28)
-
Specification