Motor driven damping arrangement and method

Apparatus for damping vibrations within a member to be damped, comprising:

• (a) motor means including
• a motor output shaft connected to the member such that vibrations within the member are detected by the motor output shaft and
• EMF generating means responsive to the detected vibrations for generating a corresponding back EMF voltage;
• and
• (b) servo circuit means connected to an input of the motor and responsive to the back EMF voltage generated by the motor means for electrically driving the motor means whereby the vibrations detected by the motor output shaft are damped and
• wherein the servo circuit means includes:
• means for producing a voltage which emulates the back EMF voltage and
• means coupled to the input of the motor and responsive to the emulated EMF voltage for applying to the input of the motor a drive voltage which damps vibrations in the member resulting in a reduction of the back EMF voltage and
• wherein the means for producing the emulated voltage includes:
• means for sensing current through the motor means,
• means responsive to the sensed current for producing an output voltage which emulates a voltage within a reactive and a passive impedance of the motor means and within the current sensing means, and
• means responsive to the output voltage and to the drive voltage for producing the back EMF emulated voltage.

Apparatus for damping vibrations within a member to be damped, comprising:

• (a) motor means including
• a motor output shaft connected to the member such that vibrations within the member are detected by the motor output shaft and
• EMF generating means responsive to the detected vibrations for generating a corresponding back EMF voltage;
• and
• (b) servo circuit means connected to an input of the motor and responsive to the back EMF voltage generated by the motor means for electrically driving the motor means whereby the vibrations detected by the motor output shaft are damped and
• wherein the vibrations are rotary vibrations within the member to be damped and wherein the motor means comprises a rotary motor and
• wherein the rotary motor includes a direct current (DC) specialized limited angle torquer motor.

Apparatus for damping vibrations within a member to be damped, comprising:

• (a) motor means including
• a motor output shaft connected to the member such that vibrations within the member are detected by the motor output shaft and
• EMF generating means responsive to the detected vibrations for generating a corresponding back EMF voltage;
• and
• (b) servo circuit means connected to an input of the motor and responsive to the back EMF voltage generated by the motor means for electrically driving the motor means whereby the vibrations detected by the motor output shaft are damped and
• wherein the certain vibrations comprise lateral vibrations within the member to be damped and wherein the motor comprises a linear motor.

Apparatus for damping vibrations within a member to be damped, comprising:

• (a) motor means including
• a motor output shaft connected to the member such that vibrations within the member are detected by the motor output shaft and
• EMF generating means responsive to the detected vibrations for generating a corresponding back EMF voltage;
• and
• (b) servo circuit means connected to an input of the motor and responsive to the back EMF voltage generated by the motor means for electrically driving the motor means whereby the vibrations detected by the motor output shaft are damped and
• wherein the member to be damped comprises a shaft of a tension supply arm forming part of a tape transport of a recorder.

A method of damping vibrations within a member to be damped, comprising:

• coupling the member to be damped to an output shaft of a motor;
• detecting vibrations within the member;
• responsive to detected vibrations in the member, producing a functionally related back EMF within the motor;
• responsive to the back EMF, generating a torque within the motor to oppose the detected vibration;
• responsive to the opposing torque, damping the vibrations.