Actuator position control with inductive sensing
AssigneeBuehler Motor GmbH
InventorsBruce Q. Du, Tanh M. Bui
Life of this patent
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Abstract
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.
Claims14
A position control system for an actuator comprising:
- a driving circuit coupled to a motor;
- a sensing inductor connected in series with said motor through said driving circuit for sensing a signal from said motor;
- an amplifier for receiving and amplifying the sensed signal;
- and
- a microprocessor for receiving and counting incoming pulses from said amplifier to obtain a pulse count, said microprocessor comparing the pulse count with a command input and, responsive to a difference between said pulse count and said command input, issuing a command signal to said driving circuit to initiate driving of said actuator.
A position control system for an actuator comprising:
- a driving circuit coupled to a motor;
- a sensing inductor connected in series with said motor through said driving circuit for sensing a voltage drop from said motor;
- and
- a processing unit for receiving incoming pulses and, responsive to a difference between a pulse count and a command input, issuing a command signal to said driving circuit to initiate driving of said actuator.
A method for sensing actuator position using an inductive sensor, comprising the steps of:
- monitoring changes in current signals from a motor through voltage drops across the inductive sensor;
- receiving, by an amplifier, a sensed signal from the inductive sensor, said amplifier reversing a polarity of and amplifying said signal;
- reading, by a microprocessor, incoming pulses from said amplifier;
- determining a pulse count;
- receiving, by said microprocessor, an actuator position command input;
- comparing said pulse count with said received actuator position command input;
- and
- driving said actuator in response to a difference between said pulse count and said command input.
Dependencies are inferred from the claim text.