Abstract: Some embodiments are directed to a system comprising a MEMS based actuator unit and a control electric circuit. The actuator unit comprising one or more MEMS actuators, each comprising a stator and a rotor and configured to define a payload position in response to electric potential between said stator and rotor. The electric circuit comprising one or more amplifiers configured to provide electric control signal to the one or more MEMS actuators to selectively vary position of said payload. The electric circuit comprises a sensing circuit configured for providing an alternating carrier signal and for monitoring said carrier signal to generate data on impedance of said one or more MEMS actuators indicative of position of the rotor with respect to the stator of said one or more MEMS actuators.