MEMS piezoresistive accelerometer sensor for gait analysis
Abstract
Microelectromechanical Systems (MEMS) based accelerometers have been reported as one
of the most popular applications in sensing methods. For establishing the microsystem
technology, Finite Element Analysis (FEA) has been reported as the most time and cost
effective way to build a model for simulation. Present work focuses on designs, analysis
and simulations of MEMS piezoresistive accelerometer sensor for gait analysis of different
size. The structure of the accelerometer is chosen to reduce the cross-axis sensitivity by
selecting an appropriate material and suitable design parameters. The accelerometers are
doped with p-type (boron diffused) silicon as their piezoresistor. A solid model has been
simulated using COMSOL Multiphysics software to find von mises stress, displacement
and sensitivity of the proposed designs. The designed accelerometers are based on the
piezoresistive effect where the value of a resistor changes with applied mechanical stress.
The changes in the resistors values are then converted to an output voltage using a
Wheatstone bridge. The simulation shows that Design 1 has maximum value of spring
constant and maximum displacement which is 91800N/m and 9.21x10-8 μm respectively.
Design 2 has maximum value of Von mises stress which is 0.001684MPa while Design 3
has the lowest value of spring constant, 3400N/m.