The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 25, 2005
Filed:
Aug. 19, 2002
Bruce Q. Du, Apex, NC (US);
Tanh M. Bui, Cary, NC (US);
Bruce Q. Du, Apex, NC (US);
Tanh M. Bui, Cary, NC (US);
Buehler Motor, Inc., Cary, NC (US);
Abstract
An actuator position control system for brush-type DC motors. The system includes a sensor, amplifier or differentiator, central control unit (microprocessor), and motor driver. The system utilizes the differential signal di/dt to indicate the falling edges of commutation spikes in the motor current profile. In a first embodiment, an inductor is selected as the signal sensor, because voltage drops across the inductor are directly proportional to di/dt. The voltage drop, L(di/dt), across the inductive sensor is input to the amplifier, amplified, and then sent to the microprocessor. In a second embodiment, a sensing resistor and a differentiator are substituted for the inductive sensor and amplifier, respectively. The microprocessor reads the output pulses from the amplifier or differentiator and compares the pulse count to an input command signal. The microprocessor then sends shaft position control information to the motor driver.