Method and system for enhanced resolution, automatically-calibrated position sensor
AssigneeUniversity of Virginia Patent Foundation
InventorZachary Buckner
Life of this patent
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Abstract
A system and method for sensing position and/or displacement of a moving, substrate, ram, target, piston, encoder wheel or the like. The system includes a plurality of transducers for generating two sinusoidal signals in quadrature related to the position and displacement of the substrate, ram or the like. Alternatively, the sinusoidal signals may be generated by other well-known devices, such as by an optical encoder or the like. The two sinusoidal signals in quadrature are processed to provide enhanced resolution compared to conventional quadrature systems. The system is also capable of self-calibration in order to accommodate fluctuations in the two sinusoidal signals in quadrature.
Claims108
A system for detecting movement of a substrate, system comprising:
- a first signal acquisition means for acquiring a first substantially sinusoidal signal related to the position of the substrate;
- a second signal acquisition means for acquiring a second substantially sinusoidal signal related to the position of the substrate that is substantially 90 degrees out of phase with the first substantially sinusoidal signal;
- a signal selection means for:
- comparing the first substantially sinusoidal signal and the second substantially sinusoidal signal,
- selecting the signal with the lesser instantaneous magnitude as the primary signal,
- selecting the signal with the greater instantaneous magnitude as the secondary signal, and
- producing a reference signal indicating whether the first substantially sinusoidal signal or the second substantially sinusoidal signal was selected as the primary signal;
- a phase angle converter means for converting the primary signal into a phase angle signal;
- and
- an angular movement detection means for:
- determining angular movement over time based on the value of the phase angle signal over time, and
- producing a corresponding angular movement signal.
A method for detecting movement of a moving substrate, comprising:
- acquiring a first substantially sinusoidal signal related to the position of said substrate;
- acquiring a second substantially sinusoidal signal related to the position of said substrate that is substantially 90 degrees out of phase with the first substantially sinusoidal signal;
- comparing the first substantially sinusoidal signal and the second substantially sinusoidal signal, selecting the signal with the lesser instantaneous magnitude as the primary signal, selecting the signal with the greater instantaneous magnitude as the secondary signal, and producing a reference signal indicating whether the first substantially sinusoidal signal or the second substantially sinusoidal signal was selected as the primary signal;
- converting the primary signal into a phase angle signal;
- and
- determining angular movement over time and producing a corresponding angular movement signal.
Dependencies are inferred from the claim text.