Torque sensor assembly
View Patent ↗A torque sensing assembly ( 10 ) includes a first sensor assembly ( 50 ) configured for sensing at least a portion of a magnetic field of a first portion ( 22 ) of a rotating shaft assembly ( 12 ) and generating a first signal ( 52 ). A second sensor assembly ( 56 ) is configured for sensing at least a portion of a magnetic field of a second portion ( 26 ) of the rotating shaft assembly ( 12 ) and generating a second signal ( 58 ). A common mode detection circuit ( 54 ) is configured for combining the first and second signals to form a combined signal and processing the combined signal to at least partially remove a common mode signal from the combined signal and generate an output signal.
1. A torque sensing assembly comprising:
a first sensor assembly comprising one or more sensor elements for generating a first magnetic intensity signal and a first integrator circuit for processing the first magnetic intensity signal to generate a first signal;
a second sensor assembly comprising one or more sensor elements for generating a second magnetic intensity signal and a second integrator circuit for processing the second magnetic intensity signal to generate a second signal; and
a common mode detection circuit comprising a balancing circuit for receiving said first signal and said second signal and balancing said first signal with respect to said second signal by combining a portion of said first signal and a portion of said second signal to generate a combined signal and at least partially remove common mode signals from said first and second signals.
2. The assembly of claim 1 wherein the first sensor assembly further includes:
a rectifying circuit for rectifying the first magnetic intensity signal, which is provided to the first integrator circuit.
3. The assembly of claim 2 wherein the rectifying circuit includes a multiplexer.
4. The assembly of claim 1 wherein the second sensor assembly further includes:
a rectifying circuit for rectifying the second magnetic intensity signal, which is provided to the second integrator circuit.
5. The assembly of claim 4 wherein the rectifying circuit includes a multiplexer.
6. The assembly of claim 1 wherein the common mode rejection circuit includes:
a differential amplification circuit, responsive to the first and second signals, for generating a differential signal; and
an output amplification circuit, responsive to the combined signal and the differential signal, for amplifying the combined signal to generate the output signal.
7. The assembly of claim 1 further comprising:
a power supply configured to provide a power signal to at least a portion of at least one of the first and second sensor assemblies; and
a soft-start controller configured to energize the power supply during a defined time period.
8. The assembly of claim 7 wherein the power signal is a variable duty-cycle power signal and the power supply is configured to regulate the duty-cycle of the variable duty-cycle power signal.
9. The assembly of claim 7 wherein the defined time period is defined by an RC time constant.
10. The assembly of claim 1 wherein the first sensor assembly includes:
a first sensor element coupled in a series configuration to a second sensor element, wherein the first and second sensor elements are radially diametrically-opposed about the rotating shaft.
11. The assembly of claim 1 wherein the second sensor assembly includes:
a first sensor element coupled in a series configuration to a second sensor element, wherein the first and second sensor elements are radially diametrically-opposed about the said shaft.
12. A method comprising:
sensing at least a portion of a magnetic field of a first portion of a rotating shaft assembly and generating a first signal;
sensing at least a portion of a magnetic field of a second portion of the rotating shaft assembly and generating a second signal; and
receiving said first signal and said second signal using a common mode detection circuit comprising a balancing circuit for balancing said first signal with respect to said second signal by combining a portion of said first signal and a portion of said second signal to generate a combined signal and at least partially remove common mode signals from said first and second signals.
13. The method of claim 12 wherein sensing at least a portion of a magnetic field of a first portion of a rotating shaft assembly includes:
generating a first magnetic intensity signal; and
processing the first magnetic intensity signal to generate the first signal.
14. The method of claim 13 wherein sensing at least a portion of a magnetic field of a first portion of a rotating shaft assembly further includes:
rectifying the first magnetic intensity signal.
15. The method of claim 12 wherein sensing at least a portion of a magnetic field of a second portion of the rotating shaft assembly includes:
generating a second magnetic intensity signal; and
processing the second magnetic intensity signal to generate the second signal.
16. The method of claim 15 wherein sensing at least a portion of a magnetic field of a second portion of the rotating shaft assembly further includes:
rectifying the second magnetic intensity signal.
17. The method of claim 12 wherein combining the first and second signals to form a combined signal includes:
generating a differential signal based upon the first and second signals; and
amplifying the combined signal, based upon the differential signal, to generate the output signal circuit.
18. The method of claim 12 further comprising:
providing a power signal to at least a portion of at least one of the first and second inductive assemblies; and
energizing the power supply during a defined time period.
19. The method of claim 18 wherein the power signal is a variable duty-cycle power signal, the method further comprising:
regulating the duty-cycle of the variable duty-cycle power signal.
20. The method of claim 18 wherein the defined time period is defined by an RC time constant.