Desenvolvimento de sensor de pressão para aplicação industrial

Abstract

This work presents the piezoresistive sensor technologies used in pressure measurement. Pressure sensors are used in a wide range of applications, among which the industrial area has an important market share. The work covers the history of pressure sensors and also the knowledge necessary to carry out the design of a piezoresistive pressure sensor for industrial use. The analysis of the mechanical deformation of the elastic element of the sensor is a very important part of its design. The information and details needed to design the pressure sensor are listed. The work presents some design considerations that must be observed during its development. The operating principle of piezoresistive sensors is also presented, which is a fundamental element for understanding the proposed sensor. The deformation piezoresistor element used in the development of the project is highlighted. It is a silicon piezoresistor, whose design and manufacture has been fully developed nationally. The work describes the methodology used in the design, construction and how the materials used in the pressure sensor were chosen. The design of the pressure sensor was tested and validated through simulation in the COMSOL software. After the construction of prototypes of the pressure sensor, they were characterized. Two different electrical connection processes for the piezoresistor elements were designed, manufactured and tested: wire bonding and conductive adhesives. Pressure sensors manufactured by wire bonding presents better performance and less dependence on operating temperature variation. A method for the sensor thermal compensation was proposed and implemented. A significant reduction in sensor error was thus obtained. The sensor without thermal compensation has an error 5.5 times greater than the sensor that has the proposed thermal compensation method.