Apparatus and method for electronic control of DC motor using an all-digital phase-locked loop

A control system for controlling movement of a DC motor, comprising:

• a movement detector to detect movement of the DC motor including:
• a carriage which is attached to the motor with a belt drive, said carriage moving in response to movement of the motor;
• and
• an encoder attached to said carnage and moving therewith, wherein the encoder outputs a feedback signal in response to movement of the motor;
• and an application specific integrated circuit including:
• a digital phase detector to compare phase of the feedback signal from the encoder with phase of a reference signal and output a comparison signal, wherein the digital phase detector models non-linear components of the reference signal;
• and
• a digital loop filter to filter noise from the comparison signal for control of the DC motor.

A control system for controlling velocity of an ink-jet print head in response to a reference signal, comprising:

• a velocity detector to detect velocity of an inkjet print head and output a corresponding feedback signal;
• a digital phase frequency detector to compare phase of the feedback signal from said velocity detector with the reference signal and output a corresponding comparison signal, wherein said digital phase frequency detector follows a describing function;
• a digital loop filter to filter noise from the comparison signal;
• and
• a motor to control velocity of the inkjet print head in response to the filtered comparison signal.

A method for controlling velocity of an inkjet print head in response to a reference signal, comprising the steps of:

• detecting a velocity of an inkjet print head and outputting a corresponding feedback signal;
• comparing phase of the feedback signal with phase of the reference signal using a digital phase frequency detector and outputting a corresponding comparison signal, said comparing step following a describing function;
• filtering noise from the comparison signal;
• and
• controlling velocity of the inkjet print head in response to the filtered comparison signal.

A control system for controlling velocity of an ink-jet print head in response to a reference signal, comprising:

• a velocity detector to detect velocity of the inkjet print head and output a corresponding feedback signal;
• a digital phase frequency detector to compare phase of the feedback signal from said velocity detector with the reference signal and output a corresponding comparison signal;
• a digital loop filter to filter noise from the comparison signal;
• and
• a motor to control velocity of the inkjet print head in response to the filtered comparison signal, wherein said phase frequency detector provides system damping by anticipating a step response of said motor, such that the amount of time that said digital loop filter changes during comparison by said digital phase detector is minimized.

A method for controlling velocity of an inkjet print head in response to a reference signal, comprising the steps of:

• detecting a velocity of the inkjet print head and outputting a corresponding feedback signal;
• comparing phase of the feedback signal with phase of the reference signal using a digital phase frequency detector and outputting a corresponding comparison signal, wherein said detecting step provides damping by anticipating a step response of the inkjet print head such that the amount of time required by said comparing step is minimized;
• filtering noise from the comparison signal;
• and
• controlling velocity of the inkjet print head in response to the filtered comparison signal.

A control system for controlling movement of a DC motor, comprising

• a movement detector to detect movement of the DC motor and output a corresponding feedback signal;
• a digital phase frequency detector to compare phase of the feedback signal from said movement detector with phase of a reference signal and output a comparison signal, wherein the digital phase frequency detector follows a describing function to model non-linear components;
• and
• a digital loop filter to filter noise from the comparison signal for control of the DC motor, wherein the digital phase frequency detector has a memory with weighted states to provide for system damping, such that the amount of time that said digital loop filter changes during comparison by said digital phase frequency detector is minimized.

A control system for controlling movement of a DC motor, comprising:

• a movement detector to detect movement of the DC motor and output a corresponding feedback signal;
• a digital phase detector to compare phase of the feedback signal from said movement detector with phase of a reference signal and output a comparison signal, wherein the digital phase detector follows a describing function;
• and
• a digital loop filter to filter noise from the comparison signal for control of the DC motor.