Encoder eccentricity correction for motion control systems
First Claim
1. A method of correcting encoder eccentricity in an image forming device that uses encoder feedback signals to generate speed and position counts to control the speed and position of a rotary encoder, the method comprising:
- receiving a plurality of pulse trains indicative of the speed of the rotary encoder;
receiving a clocking signal having a frequency greater than the pulse trains;
generating a series of periodic sampling points;
calculating a corrected position count based at least partly on a first position count that is determined by counting a number of cycles of the clocking signal that elapse between a sampling point and a transition of a first of the plurality of pulse trains and a second position count based upon a second of the plurality of pulse trains; and
adjusting the speed of the rotary encoder and maintaining a substantially constant value tor the corrected position count to effect position control.
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Accused Products
Abstract
Correction of rotary encoder eccentricity in an image forming device having a motor controller using period and position pulse train feedback signals. A motor includes an encoder disc rotating with the motor and at least two encoder sensors disposed at different circumferential positions about the encoder disc. A controller may use a high speed clock to calculate a corrected speed count based on speed counts determined from the number of clock cycles that elapse per cycle of pulse trains from the encoders. The controller may also calculate a corrected position count based at least partly on one or more position counts determined from the number of clock cycles that elapse between periodic sampling points and transitions of encoder pulse trains. The corrected position count may also be calculated based on a position count and one or more speed counts.
26 Citations
27 Claims
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1. A method of correcting encoder eccentricity in an image forming device that uses encoder feedback signals to generate speed and position counts to control the speed and position of a rotary encoder, the method comprising:
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receiving a plurality of pulse trains indicative of the speed of the rotary encoder; receiving a clocking signal having a frequency greater than the pulse trains; generating a series of periodic sampling points; calculating a corrected position count based at least partly on a first position count that is determined by counting a number of cycles of the clocking signal that elapse between a sampling point and a transition of a first of the plurality of pulse trains and a second position count based upon a second of the plurality of pulse trains; and adjusting the speed of the rotary encoder and maintaining a substantially constant value tor the corrected position count to effect position control. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of correcting encoder eccentricity in an image forming device that uses feedback signals from a rotary encoder to control speed and position of the rotary encoder, the method comprising:
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positioning a first encoder sensor and a second encoder sensor at different positions about an encoder wheel; determining a first speed count and a second speed count by counting a number of clock cycles that elapse per cycle of a pulse train received from the first encoder sensor and the second encoder sensor, respectively; determining a first position count by counting a number of clock cycles that elapse between a periodic command pulse and a transition of the pulse train received from the first encoder sensor; calculating a corrected speed count based upon an average of the first speed count and the second speed count; calculating a corrected position count based at least partly on the first position count; and maintaining a substantially constant value for the corrected speed count and for the corrected position count by adjusting the speed of the rotary encoder to effect speed and position control of the encoder wheel. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of correcting encoder eccentricity in an image forming device that uses encoder feedback signals to generate speed and position counts to control the speed and position of a rotary encoder, the method comprising:
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receiving a plurality of pulse trains indicative of the speed of the rotary encoder; receiving a clocking signal having a frequency greater than the pulse trains; generating a series of periodic sampling points; calculating a corrected speed count by averaging a first speed count and a second speed count, the first speed count and the second speed count determined by counting a number of cycles of the clocking signal that elapse per cycle of pulse trains received from rotary encoder sensors that are disposed about an encoder disc, substantially 180 rotary degrees apart from one another, respectively; and adjusting the speed of the rotary encoder and maintaining a substantially constant value for the corrected speed count to effect speed control. - View Dependent Claims (23, 24, 25, 26, 27)
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Specification