Magnetostrictive position transducer having square-wave-in-quadrature-output

• US 5,206,586 A
• Filed: 07/14/1992
• Issued: 04/27/1993
• Est. Priority Date: 03/11/1991
• Status: Expired due to Term

• Current Assignee: MTS Systems Corporation (Illinois Tool Works Inc.)
• Original Assignee: MTS Systems Corporation (Illinois Tool Works Inc.)
• Inventors: Russell, Lawrence J., Yauch, Steven S., Peterson, Wade D.
• Primary Examiner(s): Snow, Walter E.
• Application Number:
  US07/913,739
• Time in Patent Office: 287 Days
• Field of Search: 324/207.11, 324/207.13, 324/207.24, 324/207.22, 324/209, 324/262, 324/226, 367/127, 367/128, 73/597, 333/148, 333/149
• US Class Current: 324/207.13
• CPC Class Codes: G01D 5/247 using time shifts of pulses
• CPC Class Codes: G01D 5/485 using magnetostrictive devices

Abstract

A magnetostrictive position measuring instrument for generating square-wave-in-quadrature output pulses indicating magnet position along a waveguide.

Claims

1. A magnetostrictive transducer for generating an indication of a magnet position along a magnetostrictive gauge comprising:

a magnetostrictive waveguide delay line;

pulse generator means for generating interrogation pulses on said delay line, in response to interrogation pulses on said delay line, in response to interrogate signals;

said magnet proximate said delay line, for converting interrogation pulses into acoustic pulses in said delay line, at the location of said magnet means;

mode converter means coupled to said wave guide for converting said acoustic pulses into corresponding echo signals;

time interval measuring means for measuring the time interval from interrogation signals to the reception of corresponding echo signals, and for generating a raw count value corresponding to said time measurement;

output conversion means for converting said raw count value to a plurality of quadrature pulses where the number of quadrature pulses indicates the position of said magnet on said waveguide.

5. The transducer of claim 1, wherein said time interval measuring means comprises:

a free running fixed frequency clock, for generating clock pulses;

a counter coupled to said clock for collecting and counting said clock pulses during the time interval corresponding to the time interval between the occurrence of said interrogation pulse and the subsequent occurrence of said echo signal, to generate said raw count value.

2. A magnetostrictive transducer for generating an indication of a magnet position along a magnetostrictive gauge comprising:

a magnetostrictive waveguide delay line;

pulse generator means for generating interrogation pulses on said delay line, in response to interrogation pulses on said delay line, in response to interrogate signals;

said magnet proximate said delay line, for converting interrogation pulses into acoustic pulses in said delay line, at the location of said magnet means;

mode converter means coupled to said waveguide for converting said acoustic pulses into corresponding echo signals;

time interval measuring means for measuring the time interval from interrogation signals to the reception of corresponding echo signals, and for generating a raw count value corresponding to said time measurement;

index position means for determining the count value for a defined index location along said waveguide and for producing an index value corresponding to said index location;

output conversion means for generating an index pulse each time said magnet moves past said index location.

3. A magnetostrictive transducer for generating an indication of a magnet position along a magnetostrictive gauge comprising:

a magnetostrictive waveguide delay line;

pulse generator means for generating interrogation pulses on said delay line, in response to interrogation pulses on said delay line, in response to interrogate signals;

said magnet proximate said delay line, for converting interrogation pulses into acoustic pulses in said delay line, at the location of said magnet means;

mode converter means coupled to said waveguide for converting said acoustic pulses into corresponding echo signals;

time interval measuring means for measuring the time interval from interrogation signals to the reception of corresponding echo signals, and for generating a raw count value corresponding to said time measurement;

index position means for determining the count value for a defined location along said waveguide and for producing an index value corresponding to said index location;

output conversion means for generating a fixed burst of output pulses corresponding to the distance of said magnet from said index location.

4. A magnetostrictive transducer for generating an indication of a magnet position along a magnetostrictive gauge comprising:

a magnetostrictive waveguide delay line;

pulse generator means for generating interrogation pulses on said delay line, in response to interrogation pulses on said delay line, in response to interrogate signals;

said magnet proximate said delay line, for converting interrogation pulses into acoustic pulses in said delay line, at the location of said magnet means;

mode converter means coupled to said waveguide for converting said acoustic pulses into corresponding echo signals;

time interval measuring means for measuring the time interval from interrogation signals to the reception of corresponding echo signals, and for generating a raw count value corresponding to said time measurement;

gradient measuring means for computing the transmission gradient of said waveguide for establishing a gradient value;

output conversion means for converting said raw count value and said gradient value, to an output signal indicative of the position of said magnet on said waveguide.

11. The transducer of claim 4, wherein said time interval measuring means comprises:

a free running fixed frequency clock, for generating clock pulses;

a counter coupled to said clock for collecting and counting said clock pulses during the time interval corresponding to the time interval between the occurrence of said echo signal, to generate said raw count value.

6. A magnetostrictive transducer for generating an indication of a magnet position along a magnetostrictive gauge comprising:

a magnetostrictive waveguide delay line;

pulse generator means for generating interrogation pulses on said delay line, in response to interrogation pulses on said delay line, in response to interrogate signals;

said magnet proximate said delay line, for converting interrogation pulses into acoustic pulses in said delay line, at the location of said magnet means;

mode converter means coupled to said waveguide for converting said acoustic pulses into corresponding echo signals;

time interval measuring means for measuring the time interval from interrogation signals to the reception of corresponding echo signals, and for generating a raw count value corresponding to said time measurement;

index position means for determining the count value for a defined index location at an arbitrarily selected position along said waveguide and for producing an index value corresponding to said index location;

output conversion means for generating an index output pulse each time said magnet moves past said index location.

7. The transducer of claim 6, wherein said output conversion means further comprises:

means for converting said raw count value to a plurality of quadrature pulses where the number of quadrature pulses indicates the position of said magnet on said waveguide.

8. The transducer of claim 6, wherein said output conversion means further comprises:

means for converting said raw count value to a plurality of quadrature pulses where the repetition rate of the quadrature pulses indicates the speed of said magnet on said waveguide.

9. The transducer of claim 8, wherein said output conversion means further comprises:

means for converting said raw count value to a plurality of quadrature pulses where the phase of said plurality of quadrature pulses indicates the direction of motion of said magnet on said wave guide.

10. The transducer of claim 6, wherein said output conversion means further comprises:

means for generating a fixed burst of output pulses corresponding to the distance of said magnet from said index location.