Resonant flexional piezoelectric force sensor based on the analysis of electromechanical impedance for aircraft application

In this article a new structure of a force sensor based on piezoelectric materials is proposed. The design and choice of measuring principle is based on the direct piezoelectric effect, for the measurement of the dynamic force, and on the analysis of the electromechanical impedance technique, for measuring the static force. This technique is based on the measurement of modes of the structure. Indeed, the application of stress on the structure will cause changes in the modes of the structure and appearance of new eigenmodes. Thus far these methods should allow for measurement of static force applied. A preliminary literature review has highlighted the benefits and potential of the technique of electromechanical impedance analysis to design a force sensor. After choosing an original structure that allows the sensor function, for different types of dynamic and static effort, a study of this technique was undertaken and led to analytically model the structure by a Mason´s scheme and determine the eigenmodes and the scale factor. The simulation on ANSYS^® software was used to determine the electromechanical parameters of the structure, using the Lagrangian approach. An experimental study of a demonstrator has validated the chosen structure, according to the dynamic and static effort by studying the variation of parameters of equivalent electromechanical scheme for different applied forces and the establishment of the scale factor for the dynamic and static effort.