Systems and methods for sensing displacement of an electromechanical transducer

A system for detecting displacement of a movable member of an electromagnetic transducer having a magnetic coil-driven linear actuator with a static member and a movable mass mechanically coupled to the static member and having a back electromotive force present across terminals of a coil of the electromagnetic transducer, the system comprising a measurement circuit communicatively coupled to the coil and configured to:

• monitor a voltage and a current associated with the coil;
• drive the electromagnetic transducer with a driving signal;
• based on the monitored voltage and current, estimate an impedance of the coil including a coil resistance and coil inductance of the linear actuator;
• and
• based on the coil inductance, determine a displacement of movable mass, wherein the displacement of the movable mass causes a change in an impedance of the linear actuator.

A method for detecting displacement of a movable member of an electromagnetic transducer having a magnetic coil-driven linear actuator with a static member and a movable mass mechanically coupled to the static member and having a back electromotive force present across terminals of a coil of the electromagnetic transducer, the method comprising:

• driving a resistive-inductive-capacitive sensor comprising the coil with a driving signal;
• measuring one or more of phase information and amplitude information associated with the resistive-inductive-capacitive sensor;
• and
• based on the one or more of phase information and amplitude information, determining a displacement of movable mass, wherein the displacement of the movable mass causes a change in an impedance of the resistive-inductive-capacitive sensor.

A method for detecting displacement of a movable member of an electromagnetic transducer having a magnetic coil-driven linear actuator with a static member and a movable mass mechanically coupled to the static member and having a back electromotive force present across terminals of a coil of the electromagnetic transducer, the method comprising:

• monitoring a voltage and a current associated with the coil;
• driving the electromagnetic transducer with a driving signal;
• based on the monitored voltage and current, estimating an impedance of the coil including a coil resistance and coil inductance of the linear actuator;
• and
• based on the coil inductance, determining a displacement of movable mass, wherein the displacement of the movable mass causes a change in an impedance of the linear actuator.