An accelerometer with integrative intensity-modulated optical encoder and patterned leaf spring for low-frequency vibration monitoring

Presented in this paper is a development of a high-performance optical accelerometer with new configuration and small size (28 × 24 × 22 mm3) that integrates an intensity-modulated linear encoder and a patterned leaf spring. In general, the sensor possesses a strong applicability and keeps a simplified layout and low cost. High resolution, large installing tolerance, and low crosstalk are achieved by employing a 20 μm-pitch optical encoder based upon Talbot Effect. Moreover, large measurement range, high eigenfrequency, and proper sensitivity is inherent in the sensor by adopting a special-designed patterned leaf spring made by beryllium copper through wet etching. Both theoretical and FEM(Finite Element Modeling) analyses are conducted to optimize the design and verify the scheme whose results show that the measuring range, resolution and sensitivity of the sensor are ±160 g, 5 mg, and 110 mV/g, respectively. That the developed optical accelerometer is appropriate for monitoring low frequency vibration between 0 and 32 Hz within a 1.9% error margin and 0.7% crosstalk has been demonstrated by experimental testing. A potential solution to resolve the contradiction between the price and performance is offered, which may help to widespread the usage of the optical-type accelerometers.