Design and Simulation of a Tunnel Magnetoresistive Accelerometer Based on Electrostatic Force Feedback

The tunnel magnetoresistive (TMR) accelerometer is a new generation of high-precision inertial sensitive devices. In this work, a micromechanical TMR accelerometer based on electrostatic force feedback is proposed. A permanent magnet film is connected with the seismic mass. The input acceleration leads to a certain displacement of the sensitive structure, thereby causes the change of the magnetic field strength. The magnitude of the acceleration is obtained by detecting the evolution of the magnetic field. On the other hand, the feedback force that pulls the mass back to the initial position is continuously generated, therefore, the mass is always in an equilibrium position. According to the simulation analysis, the simulated sensitivity of the sensitive structure is 125.6um/g and the maximum value of the magnetic field intensity changing with the displacement is 0.1mT/mm. Consequently, the mechanical sensitivity of the micromechanical accelerometer in our proposal design is 12.56uT/g. With the effective electrostatic force feedback structure design, the proposed tunnel magnetoresistive accelerometer has a more extensive dynamic range and remarkable stability.