Magnetic position and orientation measurement system
First Claim
1. A magnetic position and orientation measurement system, comprising:
- (a) a three dimensional space of known dimensions;
(b) an object located within said space, the position and orientation of which is to be measured;
(c) a single elongated bar permanent magnet fixedly attached to said object; and
(d) a plurality of three-axis Hall-effect antennas mounted within said space for sensing the magnetic field of said permanent magnet, each axis of each said antenna being substantially parallel to a corresponding axis of all other ones of said antenna;
(e) said antennas being connected to electrical circuitry enabling the inputting thereto of data related to the magnetic field of said permanent magnet as sensed by said antennas and therefrom calculating the position and orientation of said permanent magnet and thereby of said object.
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Accused Products
Abstract
A system is disclosed which enables the measurement of the position and orientation of a permanent magnet within a three dimensional region in five degrees of freedom. In order to sense the position and orientation of the permanent magnet, three three-axis antennas are created with each antenna being composed of three mutually orthogonal Hall-effect devices. As is known, Hall-effect devices produce an output voltage proportional to the product of the input current, the magnet flux density and the sine of the angle between the magnet flux density and the plane of the Hall-effect device. The output voltages from the nine Hall-effect devices utilized in the system are inputted into a microprocessor device which first calculates an estimate of the position and orientation of the magnet utilizing a nonlinearized algorithm. Subsequently, the microprocessor uses a linearized algorithm to calculate the precise position and orientation of the permanent magnet. If desired, and in situations where operation is limited to a restricted area, the system may operate utilizing only six Hall-effect devices deployed as two 3-axis antennas. In one example of a system made in accordance with the present invention, operating in an area of approximately one cubic meter, the location of the permanent magnet was updated approximately 100 times per second and the location of the permanent magnet was determined with an accuracy of better than 0.5% in position and 0.5° in orientation.
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Citations
13 Claims
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1. A magnetic position and orientation measurement system, comprising:
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(a) a three dimensional space of known dimensions; (b) an object located within said space, the position and orientation of which is to be measured; (c) a single elongated bar permanent magnet fixedly attached to said object; and (d) a plurality of three-axis Hall-effect antennas mounted within said space for sensing the magnetic field of said permanent magnet, each axis of each said antenna being substantially parallel to a corresponding axis of all other ones of said antenna; (e) said antennas being connected to electrical circuitry enabling the inputting thereto of data related to the magnetic field of said permanent magnet as sensed by said antennas and therefrom calculating the position and orientation of said permanent magnet and thereby of said object. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of measuring the position and orientation of an object, comprising the steps of:
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(a) providing a space of known dimensions; (b) locating an object within said space, the position and orientation of which are to be measured; (c) attaching a single elongated bar permanent magnet to said object in a known position and orientation with respect to said object; (d) locating a plurality of three-axis Hall-effect antennas in predetermined regions within said sapce, each axis of each said antenna being substantially parallel to a corresponding axis of all other ones of said antennas; (e) measuring the magnetic field of said permanent magnet with said antennas; (f) inputting data collected from said measuring step into calculating means; and (g) calculating the position and orientation of said object. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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Specification