Abstract:
This paper presents a novel model of a closed loop capacitive accelerometer. Capacitive accelerometer is able to detect the displacement/position of a vehicle by means of Position-Velocity-Acceleration (PVA) model. The closed loop design is design to overcome the steady state error obtained in the equivalent open loop design. Therefore, in this paper, a parallel Proportional Integral Derivative (PID) controller with a derivative filter is designed to establish a unity feedback accelerometer for the purpose of reducing or eliminating the steady state error. The accelerometer gave an exact linear dependence of displacement on a step-like function of acceleration signal input. Matlab/Simulink software was used to design the control system and construct the overall proposed mathematical model. Test show that, for acceleration value of ±1 gravity (g) produces displacement of ±1 meter (m). The system produces an initial spike with a transient time of less than 0.1 secs. This is same for an acceleration of ±10 g. The use of PID controller with a derivative filter in this paper provide a significant improvement in predicting the linear dependence relationship between acceleration and displacement than the traditional approach of continuous tuning of PID for accelerometer system stability.
