Precision virtual encoder
First Claim
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1. A motor drive providing a torque signal to a motor, comprising:
- a signal source outputting a desired motor speed signal; and
a virtual encoder receiving the desired motor speed signal and producing a delta position signal based at least in part on the desired motor speed signal, wherein the virtual encoder outputs a desired position signal that differs from the delta motor position signal by an error that is maintained to a value less than a predetermined integer.
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Abstract
A virtual encoder is provided as a software component of a motor drive that integrates a command speed to produce a desired position drive signal. The desired position drive signal is converted to an actual position drive signal that is constantly maintained within a predetermined integer error margin of the desired position drive signal.
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Citations
23 Claims
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1. A motor drive providing a torque signal to a motor, comprising:
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a signal source outputting a desired motor speed signal; and
a virtual encoder receiving the desired motor speed signal and producing a delta position signal based at least in part on the desired motor speed signal, wherein the virtual encoder outputs a desired position signal that differs from the delta motor position signal by an error that is maintained to a value less than a predetermined integer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A virtual encoder for a motor drive, comprising:
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a calculated position signal output device using a desired velocity signal and a constant scale factor to produce a delta position signal;
a converter that receives the delta position signal and outputs an actual position signal that deviates from the delta position signal by an error margin;
an error correction mechanism that receives the error margin and outputs a correction signal when the error margin accumulates beyond a predetermined threshold; and
an accumulator that adds the actual position signal to the correction signal to produce a corrected position signal; and
an output device outputting the corrected position signal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A method for producing a desired position signal for a motor drive, the method comprising the steps of:
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A) receiving a desired velocity signal and constant scale factor;
B) based on the desired velocity signal and constant scale factor, computing a delta position signal;
C) converting the delta position signal to an actual position signal that deviates from the delta position signal by an error margin;
D) outputting a correction signal when the error margin exceeds a predetermined threshold; and
E) adding the actual position signal to the correction signal to produce the desired position signal. - View Dependent Claims (20, 21, 22, 23)
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Specification