Abstract: An electrostatic microactuator, known as a “Scratch Drive Actuator” or SDA, is based on a collective set of distributed elementary SDAs of small size that are associated with one another and that integrates a large number so as to allow the addition of the forces generated by each of the SDAs in the collective set. An external mechanical prestress, formed by a homogeneous external pressure in the form of a bias voltage applied at rest to the associated SDAs, is applied to the SDAs to allow a superposition of the forces generated by the associated SDAs. This is done while communicating to an external load the entire driving force emanating from the collective behavior of the SDAs. The electrostatic attraction forces established by the bias voltage are used to calibrate an individualized prestress for each actuator involved in the collective set.