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US 9,803,998 B1Granted
Absolute position sensor with fine resolution
AssigneeJoral LLC
InventorCarl D. Schrubbe
Life of this patent
Estimating the term…
Abstract
An absolute position sensor having a detector with a plurality of Wiegand wire sensors that each have a pair of Hall sensors bracketing or straddling the Wiegand wire used by a processor in interpolating relative ratios of signals from the bracketing Hall sensors in not only providing increased fine position determination between magnets but also providing coarse position count increment or decrement verification. Such an absolute position sensor provides increased fine position determination accuracy while also enhancing increment and/or decrement error prevention and/or correction during position sensor operation.
Claims24
An absolute position sensor comprising:
- a detector having a plurality of Wiegand wires and a plurality of Hall sensors that sense a magnet of a track carrying a plurality of pairs of the magnets in incrementing or decrementing a coarse position counter and resolving a fine position between magnets using interpolation;
- wherein each Wiegand wire is bracketed by a pair of Hall sensors that sense the same magnet triggering the Wiegand wire bracketed thereby outputting analog signals whose ratio is monitored until the ratio reaches a threshold indicating the magnet has moved to a position relative to the triggered Wiegand wire bracketed thereby necessitating a change in a count of the coarse position counter;
- and
- wherein when the ratio of the signal of the one Hall sensor disposed to one side of the triggered Wiegand wire relative to the signal of the other Hall sensor disposed to the other side of the triggered Wiegand wire reaches one or unity, the count of the coarse position counter is changed.
1 more element
An absolute position sensor comprising:
- (a) a detector having (i) a coarse position detector comprised of a digital value magnetic field sensor that outputs a signal when a magnetic field or flux of one of a plurality of pairs of spaced apart magnets is sensed thereby, the signal indicative of a coarse position of the sensed one of the magnets and (ii) a fine position detector comprised of a pair of spaced apart analog value magnetic field sensors that each senses a respective strength of the magnetic field or flux of the sensed one of the magnets and outputs an analog signal whose value is proportional to the respective sensed magnetic field of flux strength of the sensed one of the magnets sensed by the analog value magnetic field sensors, and
- (b) a position determining system comprised of a fine position resolution subsystem that receives the values of the analog signals from the pair of analog value magnetic field sensors respectively sensing the respective magnetic field or flux strength of the sensed one of the magnets, the position determining system configured to obtain a ratio of the values of the analog signals from the pair of analog value magnetic field sensors respectively sensing the magnetic field or field strength of the sensed one of the magnets, the ratio corresponding to a position where the sensed one of the magnets is located between the pair of analog value magnetic field sensors.
An absolute position sensor comprised of:
- (a) an elongate track carrying a plurality of pairs of magnets spaced apart along the track;
- and
- (b) a position detecting head disposed adjacent the track, the position detecting head comprising:
- (1) a coarse position signal detector having a counting signal detecting sensor comprised of a Wiegand wire that outputs a signal when a magnetic field or magnetic flux of an adjacent one of the magnets moving relative to the head triggers the Wiegand wire;
- (2) a fine position signal detector comprised of a pair of spaced apart magnetic field or magnetic flux strength sensors with one of the magnetic field or magnetic flux strength sensors disposed to one side of the Wiegand wire and the other one of the magnetic field or magnetic flux strength sensors disposed to the other side of the Wiegand wire, the pair of magnetic field or magnetic flux strength sensors respectively outputting a signal whose value relates to the strength of the magnetic field or magnetic flux of the adjacent one of the magnets triggering the Wiegand wire;
- and
- (3) a processor (i) configured with a coarse position counter used to determine a coarse position of the track relative to the head, (ii) configured to increment or decrement the coarse position counter indicative of a change in the position of the track relative to the head a) when a signal is outputted by the counting signal detecting sensor when relative movement between the track and head causes an adjacent one of the magnets to trigger the Wiegand wire, and b) upon a ratio of the signal values outputted by the pair of magnetic field or magnetic flux strength sensors sensing magnetic field or magnetic flux of the adjacent one of the magnets triggering the Wiegand wire reaching one or unity during the relative movement between the track and head resulting in the adjacent one of the magnets triggering the Wiegand wire;
- and (iii) configured to determine a position of the track relative to the head more precise than the coarse position by using the ratio of the signal values outputted by the pair of magnetic field or magnetic flux strength sensors sensing the magnetic field or magnetic flux of the adjacent one of the magnets triggering the Wiegand wire, the ratio of the signal values outputted by the pair of magnetic field or magnetic flux strength sensors corresponding to a position where the adjacent one of the magnets triggering the Wiegand is located between the pair of magnetic field or magnetic flux strength sensors.
5 more elements
Dependencies are inferred from the claim text.