Temperature information detecting device for angle sensor and position detecting device

• US 6,896,407 B2
• Filed: 11/01/2002
• Issued: 05/24/2005
• Est. Priority Date: 11/05/2001
• Status: Active Grant

• Current Assignee: Yamatake Corporation
• Original Assignee: Yamatake Corporation
• Inventors: Nagasaka, Fumio, Akano, Shinichi, Nomiyama, Takashi
• Primary Examiner(s): Gutierrez, Diego
• Assistant Examiner(s): PRUCHNIC, STANLEY J
• Application Number:
  US10/285,460
• Publication Number:
  US 20030086470A1
• Time in Patent Office: 935 Days
• Field of Search: 374/6, 374/141, 374/142, 374/176, 374/177, 374/183, 33/1.PT, 33/1.N, 324/202, 324/207.11, 324/207.12, 324/207.19, 324/207.21, 324/207.25, 324/252, 251/129.04
• US Class Current: 374/142
• CPC Class Codes: F16K 37/0083 by measuring valve parameters

Abstract

A temperature information detecting device for an angle sensor is provided for detecting only temperature-dependent components based on middle-point potentials when a constant current is supplied to a bridge circuit for an angle sensor, for acquiring a temperature of the angle sensor from the temperature-dependent components, for employing compensating information corresponding to the acquired temperature without separately providing any additional temperature sensor, and for making temperature compensation of the output of the temperature sensor in automatically controlling the valve opening of a flow control valve.

Claims

1. A device for acquiring temperature information indicative of ambient temperature of an angle sensor having a bridge circuit composed of four magnetoresistive elements whose resistive properties vary with direction of a magnetic flux across said bridge circuit and with temperature, and magnetic field generating means for generating a magnetic field that acts on said bridge circuit to produce said magnetic flux, comprising:

a constant current supply that provides a constant electric current to said bridge circuit; and

temperature information determining means for obtaining a signal indicative of ambient temperature of said angle sensor, said signal being derived from midpoint voltage potentials of branches of said bridge circuit;

wherein said temperature information determining means comprises means for adding together midpoint voltage potentials of branches of said bridge circuit.

2. A device as set forth in claim 1, further comprising an analog-to-digital converter for converting said midpoint voltage potentials to digital signals before said midpoint voltage potentials are added together by said adding means.

3. A device for acquiring temperature information indicative of ambient temperature of an angle sensor having a bridge circuit composed of four magnetoresistive elements whose resistive properties vary with direction of a magnetic flux across said bridge circuit and with temperature, and magnetic field generating means for generating a magnetic field that acts on said bridge circuit to produce said magnetic flux, comprising:

a constant current supply that provides a constant electric current to said bridge circuit; and

temperature information determining means for obtaining a signal indicative of ambient temperature of said angle sensor, said signal being derived from midpoint voltage potentials of branches of said bridge circuit;

wherein said constant current supply comprises a differential amplifier that receives an output of said bridge circuit at one input terminal thereof and receives a constant reference voltage at another input terminal thereof, and outputs said constant electric current from an output terminal thereof to an input terminal of said bridge circuit.

4. A position detection device, comprising:

an angle sensor having a bridge circuit composed of four magnetoresistive elements whose resistive properties vary with direction of a magnetic flux across said bridge circuit and with temperature, and magnetic field generating means for generating a magnetic field that acts on said bridge circuit to produce said magnetic flux, said magnetic field generating means being coupled to one end of a movable member that changes said magnetic flux direction as a function of a changing angle;

a constant current supply that provides a constant electric current to said bridge circuit;

angle determining means for obtaining a first signal indicative of an angle of said movable member, said first signal being derived from midpoint voltage potentials of branches of said bridge circuit;

temperature information determining means for obtaining a second signal indicative of ambient temperature of said angle sensor, said second signal being derived from midpoint voltage potentials of branches of said bridge circuit;

positional information determining means for determining a position of a mechanism coupled to another end of said movable member, based on said first signal; and

temperature compensation means for correcting the position determined by said positional information determining means for errors caused by changes in said ambient temperature, based on said second signal;

wherein said angle determining means comprises means for subtracting one midpoint voltage potential of a first branch of said bridge circuit from a second midpoint voltage potential of a second branch of said bridge circuit.

5. A position detection device, comprising:

an angle sensor having a bridge circuit composed of four magnetoresistive elements whose resistive properties vary with direction of a magnetic flux across said bridge circuit and with temperature, and magnetic field generating means for generating a magnetic field that acts on said bridge circuit to produce said magnetic flux, said magnetic field generating means being coupled to one end of a movable member that changes said magnetic flux direction as a function of a changing angle;

a constant current supply that provides a constant electric current to said bridge circuit;

angle determining means for obtaining a first signal indicative of an angle of said movable member, said first signal being derived from midpoint voltage potentials of branches of said bridge circuit;

temperature information determining means for obtaining a second signal indicative of ambient temperature of said angle sensor, said second signal being derived from midpoint voltage potentials of branches of said bridge circuit;

positional information determining means for determining a position of a mechanism coupled to another end of said movable member, based on said first signal; and

temperature compensation means for correcting the position determined by said positional information determining means for errors caused by changes in said ambient temperature, based on said second signal;

wherein said temperature information determining means comprises means for adding together midpoint voltage potentials of branches of said bridge circuit.

6. A position detection device as set forth in claim 5, further comprising an analog-to-digital converter for converting said midpoint voltage potentials to digital signals before said midpoint voltage potentials are added together by said adding means.

7. A position detection device, comprising:

an angle sensor having a bridge circuit composed of four magnetoresistive elements whose resistive properties vary with direction of a magnetic flux across said bridge circuit and with temperature, and magnetic field generating means for generating a magnetic field that acts on said bridge circuit to produce said magnetic flux, said magnetic field generating means being coupled to one end of a movable member that changes said magnetic flux direction as a function of a changing angle;

a constant current supply that provides a constant electric current to said bridge circuit;

angle determining means for obtaining a first signal indicative of an angle of said movable member, said first signal being derived from midpoint voltage potentials of branches of said bridge circuit;

temperature information determining means for obtaining a second signal indicative of ambient temperature of said angle sensor, said second signal being derived from midpoint voltage potentials of branches of said bridge circuit;

positional information determining means for determining a position of a mechanism coupled to another end of said movable member, based on said first signal; and

temperature compensation means for correcting the position determined by said positional information determining means for errors caused by changes in said ambient temperature, based on said second signal;

wherein said constant current supply comprises a differential amplifier that receives an output of said bridge circuit at one input terminal thereof and receives a constant reference voltage at another input terminal thereof, and outputs said constant electric current from an output terminal thereof to an input terminal of said bridge circuit.

8. A flow control valve system, comprising:

a flow control valve having an inlet for receiving a fluid, an outlet for discharging said fluid, and a controllable flow mechanism between said inlet and said outlet for controlling flow of said fluid between said inlet and said outlet;

a movable member having one end thereof attached to said controllable flow mechanism;

an angle sensor having a bridge circuit composed of four magnetoresistive elements whose resistive properties vary with direction of a magnetic flux across said bridge circuit and with temperature, and magnetic field generating means for generating a magnetic field that acts on said bridge circuit to produce said magnetic flux, said magnetic field generating means being coupled to another end of said movable member, such that changes in position of said controllable flow mechanism result in changes in angle of said movable member, which in turn result in changes in said magnetic flux;

a constant current supply that provides a constant electric current to said bridge circuit;

angle determining means for obtaining a first signal indicative of an angle of said movable member, said first signal being derived from midpoint voltage potentials of branches of said bridge circuit;

temperature information determining means for obtaining a second signal indicative of ambient temperature of said angle sensor, said second signal being derived from midpoint voltage potentials of branches of said bridge circuit;

positional information determining means for determining a position of a mechanism coupled to another end of said movable member, based on said first signal;

temperature compensation means for correcting the position determined by said positional information determining means for errors caused by changes in said ambient temperature, based on said second signal; and

control means for controlling the position of said controllable flow mechanism by comparing an external valve setting value with a corrected position signal produced by said temperature compensation means and providing a control signal to said controllable flow mechanism in accordance with a result of the comparison;

wherein said angle determining means comprises means for subtracting one midpoint voltage potential of a first branch of said bridge circuit from a second midpoint voltage potential of a second branch of said bridge circuit.

9. A flow control valve system, comprising:

a flow control valve having an inlet for receiving a fluid, an outlet for discharging said fluid, and a controllable flow mechanism between said inlet and said outlet for controlling flow of said fluid between said inlet and said outlet;

a movable member having one end thereof attached to said controllable flow mechanism;

an angle sensor having a bridge circuit composed of four magnetoresistive elements whose resistive properties vary with direction of a magnetic flux across said bridge circuit and with temperature, and magnetic field generating means for generating a magnetic field that acts on said bridge circuit to produce said magnetic flux, said magnetic field generating means being coupled to another end of said movable member, such that changes in position of said controllable flow mechanism result in changes in angle of said movable member, which in turn result in changes in said magnetic flux;

a constant current supply that provides a constant electric current to said bridge circuit;

angle determining means for obtaining a first signal indicative of an angle of said movable member, said first signal being derived from midpoint voltage potentials of branches of said bridge circuit;

temperature information determining means for obtaining a second signal indicative of ambient temperature of said angle sensor, said second signal being derived from midpoint voltage potentials of branches of said bridge circuit;

positional information determining means for determining a position of a mechanism coupled to another end of said movable member, based on said first signal;

temperature compensation means for correcting the position determined by said positional information determining means for errors caused by changes in said ambient temperature, based on said second signal; and

control means for controlling the position of said controllable flow mechanism by comparing an external valve setting value with a corrected position signal produced by said temperature compensation means and providing a control signal to said controllable flow mechanism in accordance with a result of the comparison;

wherein said temperature information determining means comprises means for adding together midpoint voltage potentials of branches of said bridge circuit.

10. A flow control valve system as set forth in claim 9, further comprising an analog-to-digital converter for converting said midpoint voltage potentials to digital signals before said midpoint voltage potentials are added together by said adding means.

11. A flow control valve system, comprising:

a flow control valve having an inlet for receiving a fluid, an outlet for discharging said fluid, and a controllable flow mechanism between said inlet and said outlet for controlling flow of said fluid between said inlet and said outlet;

a movable member having one end thereof attached to said controllable flow mechanism;

an angle sensor having a bridge circuit composed of four magnetoresistive elements whose resistive properties vary with direction of a magnetic flux across said bridge circuit and with temperature, and magnetic field generating means for generating a magnetic field that acts on said bridge circuit to produce said magnetic flux, said magnetic field generating means being coupled to another end of said movable member, such that changes in position of said controllable flow mechanism result in changes in angle of said movable member, which in turn result in changes in said magnetic flux;

a constant current supply that provides a constant electric current to said bridge circuit;

angle determining means for obtaining a first signal indicative of an angle of said movable member, said first signal being derived from midpoint voltage potentials of branches of said bridge circuit;

temperature information determining means for obtaining a second signal indicative of ambient temperature of said angle sensor, said second signal being derived from midpoint voltage potentials of branches of said bridge circuit;

positional information determining means for determining a position of a mechanism coupled to another end of said movable member, based on said first signal;

temperature compensation means for correcting the position determined by said positional information determining means for errors caused by changes in said ambient temperature, based on said second signal; and

control means for controlling the position of said controllable flow mechanism by comparing an external valve setting value with a corrected position signal produced by said temperature compensation means and providing a control signal to said controllable flow mechanism in accordance with a result of the comparison;

wherein said constant current supply comprises a differential amplifier that receives an output of said bridge circuit at one input terminal thereof and receives a constant reference voltage at another input terminal thereof, and outputs said constant electric current from an output terminal thereof to an input terminal of said bridge circuit.