Diagnosis of an Inertial Measurement Unit based on set membership estimation

This paper compares two diagnostic techniques applied to MEMS sensors of an Inertial Measurement Unit (IMU). The sensors considered in this study are a triaxis accelerometer and a triaxis magnetometer. Note that rate gyros measurements are not considered here. The goal of the IMU is to sense the attitude of a rigid body on which it is embedded. The measurement equations are non-linear in the attitude parameters which are first estimated from five over six measurements. Then, each measurement equation together with the estimated parameters, provides an predicted measurement. Lastly, the residual is computed and analyzed with a signature table to detect and isolate the fault. Two estimation techniques are implemented. The first approach is based on parameter estimation with nonlinear optimization technique while the second one makes use of set membership estimation. Both techniques are applied to the detection of faults in the IMU fixed on a quadrotor in quasi-static mouvement.