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US 7,262,569 B2Granted
Electronic rotor pointing with high angular resolution
AssigneeTrimble Navigation Limited
InventorFrank B. Douglas
Life of this patent
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AssigneeTrimble Navigation Limited
InventorFrank B. Douglas
Estimating the term…
A laser level with a sensorless DC motor controller having a feedback sampling circuit connected in parallel with the coil to sense back EMF. An integrator provides a feedback signal from the sensed back EMF, which the amplified difference from a reference level is used as a pulse width control signal. A pulse width modulation generator uses the control signal to generate variable “on” time pulse widths for each motor drive pulse such that high resolution is provided to the DC motor, permitting accurate rotor position at low rotational speeds. It is emphasized that this abstract is provided to comply with the rules requiring an abstract to allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that is will not be used to interpret or limit the scope or meaning of the claims.
A method for providing improved angular resolution to a DC motor, the method comprising:
A method of providing improved angular resolution at rotational speeds below about 1 rpm to a rotor of a sensorless permanent magnet DC motor used to move and position a beam of electromagnetic energy, said method comprising:
A motor controller for driving a sensorless permanent magnet DC motor with a motor drive pulse and providing an improved angular resolution for rotor pointing, the motor controller comprising:
Dependencies are inferred from the claim text.