Research on a small tunnel magnetoresistive accelerometer based on 3D printing

The design, simulation, fabrication and experiments of a small tunnel magnetoresistive accelerometer based on 3D printing are presented in this paper. The new tunnel magnetoresistive accelerometer which consists of tunnel magnetoresistive sensors and a proof mass with permanent magnetic films senses magnetic field variation through the tunnel magnetoresistance effect to measure input acceleration. The linear movement modes of tunnel magnetoresistive accelerometer along y and z direction are verified by the Ansys simulation. The theoretical model and physical finite element model of magnetic field are constructed to analyze the magnetic field distribution and magnetic field change rate around the tunnel magnetoresistive sensor, which can be used to find the maximum sensitivity along y and z direction. Simultaneously, the simulation results demonstrate that the theoretical model and the finite element model of magnetic field have good consistency. The small tunnel magnetoresistive accelerometer fabricated by 3D printing with the material of resin has a device dimension of 17 mm (length) × 17 mm (width) × 5 mm (height). The preliminary experimental results demonstrate that the maximal sensitivities of tunnel magnetoresistive accelerometer under the gap of 4 mm are approximately 409.01 mV/g and − 401.30 mV/g along the y and z direction respectively. Simultaneously, the prototype of tunnel magnetoresistive accelerometer has bias stabilities of 81.60 μg and 64.40 μg under linear movement modes along y and z direction respectively.