Buehler Motor Gmbh

Saia-burgess Automotive Inc.

Bruce Q Du

Tanh M Bui

Jeffrey D Mobley

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.

Actuator position control with signal sensing

A mechanically-commutated DC motor has a mechanical commutation system and an &ldquo;inside-out&rdquo; configuration, in which the stator assembly comprises the windings and the rotor assembly comprises the permanent magnet. The motor includes a rotor assembly, a stator assembly, a plurality of terminating conductive pads, and positive and negative stationary power supply terminals. The stator assembly includes a plurality of lamination stacks positioned around a central aperture and a plurality of copper coils, each coil being wound around one of the lamination stacks. The rotor assembly includes a rotor body with a permanent magnet ring and a non-conductive timing cam integrated into one face of the rotor body. The permanent magnet ring is radially magnetized in an alternating polarity pattern with at least one pair of poles. The mechanical commutation system comprises the timing cam integrated into the rotor assembly, the power supply terminals, and the conductive pads. There are the same number of conductive pads as stator coils. Each conductive pad has first and second flexible contacts selectively movable into and out of electrical contact with the positive and negative power supply terminals, respectively, in response to the action of the timing cam. Adjacent ends of adjacent coils terminate on a common conductive pad, so that the ends of each coil terminate on two different conductive pads, and each conductive pad receives the ends of two different coils.

Mechanically-commutated DC motor

An actuator position control system for brush-type DC motors. The system includes a sensing inductor, amplifier, 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. 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. The microprocessor reads the output pulses from the amplifier and compares the pulse count to an input command signal. The microprocessor then sends shaft position control information to the motor driver.

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Apex, NC, United States of America

Bruce Q Du