SAW sensor validation and instrumentation for torque and temperature measurement

• Autor(a) principal: Silva, Diogo Fonte da
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/22736
• topic: Ondas de superfície acústicas; Medição de temperatura

The work here presented is inserted in the framework of the RTMGear Project, that has the objective of measuring several physical parameters, such as torque and temperature, directly within the rotating parts present in a power reduction gearbox. The urge of this study comes from the aircraft industry demand for systems able to perform real-time monitoring of torque in the most critical components operating inside a gearbox. However, the existing sensing technologies have limitations in terms of accuracy. There are also considerable di culties to its implementation such as space constraints and very harsh conditions which make inappropriate the use of cables and electronic devices inside the gearbox. For this e ect, sensing devices based in SAW(Surface Acoustic Waves) technology were used. This devices are microelectromechanic (MEMS) systems whose characteristics are appropriate to the harsh conditions at hand. In order to proceed with the study two mechanical set- ups have been fabricated, to support the sensors evaluation tests. The rst consisted in a static set- up designed to proceed to the calibration of the strain sensors for torque measurement. The second was a dynamic set- up designed to reach rotation speed as high as 2500 rpm and with the capability of heating the sensors application area above its operating range. This set- up accommodated tests to evaluate the e ect of speed and temperature in the uncertainty of the measurements and nally, an experiment to perform torque measurement with temperature compensation was made. Tests to evaluate the curve dependence of the SAW sensors wrt temperature and the communication link established by two special antennas designated as RF rotary Couplers, used to establish wireless connection in rotative setups were also realized. The results obtained allowed the achievement of several conclusion regarding the work done and future improvements, given that a complete study on the sensors behaviour with respect to the physical quantities being analysed was made and conclusions about the e ect of speed and temperature in the measurements are obtained. However, in order to obtain validation of the technology for gearbox instrumentation, actual torque measurements in a broader range (0 to 250 Nm) with compensation of temperature and vibration, under broader ranges of speed (up to 3000 rpm) and temperature (between -25 oC up to 85o C or more) would have to be accomplished.