The aim of this paper is to investigate the design and the integration of a static force sensor based on a resonant bulk acoustic wave piezoelectric transducer. Experimental measurements of the electrical admittance spectrum show its dependence on the applied force. We noticed that the quality of the frequency response for a given vibration mode degrades with the increase of the applied force, which limits the force measuring range. The root cause of the response-stress dependence is investigated by means of the developed analytical model and a finite element analysis. The analysis results show that the selected operating vibration mode, the components of the structure on which the piezoelectric specimen is positioned and the boundary conditions at the contact interfaces between all the components have a direct effect on the electrical admittance spectrum. A modified structure was proposed to enhance the quality of the frequency response. The experimental tests show higher measuring range (up to 1500 N).

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Abstract. This paper focuses on the design of a wireless power supply system for low power devices (e.g. sensors) located in harsh electromagnetic environment with ferromagnetic and conductive materials. Such particular environment could be found in linear and rotating actuators. The studied power transfer system is based on the resonant magnetic coupling between a fixed transmitter coil and a moving receiver coil. The technique was utilized successfully for rotary machines. The aim of this paper is to extend the technique to linear actuators. A modeling approach based on 2D Axisymmetric Finite Element model and an electrical lumped model based on the two-port network theory is introduced. The study shows the limitation of the technique to transfer the required power in the presence of ferromagnetic and conductive materials. Parametric and circuit analysis were conducted in order to design a resonant magnetic coupler that ensures good power transfer capability and efficiency. A design methodology is proposed based on this study. Measurements on the prototype show efficiency up to 75% at a linear distance of 20 mm.