Simulation design of a laser-type pressure sensor

摘要

Laser triangulation is a mature and widely used technology. It has advantages of high accuracy, rapid, and non-contact. This paper first applied it to the measurement of pressure, and proposed and designed a laser-type pressure sensor. The sensor measured the center deflection of the circular pressure-sensitive diaphragm using the laser triangulation, then determined the pressure on the diaphragm according to the small-deflection theory. In the aspect of optical system, the sensor used the principle of lens imaging of magnification and constant focus combining with the high-resolution photodetector, which improved the system accuracy effectively. The paper first established the mathematical model of the laser triangulation in view of the high accuracy, small size requirements. Afterward determined the parameters of the diaphragm in light of the linear range and measurement accuracy of the pressure, and did the finite element analysis of the diaphragm using ANSYS. The analysis demonstrates that within the pressure range, meeting the small-deflection theory, the relationship between the pressure and the deflection is nearly linear. The minimum pressure of the sensors designed is 50Pa, the pressure range is 1.4614MPa, and the maximum relative nonlinearity error of the diaphragm is 1.273%.