Well-conditioned observer design for two-output systems

It was shown that the robustness of deterministic observers with respect to modeling errors, measurement bias and round-off errors can be represented by a single performance index, chi (2)(P), the condition number of the obse rver eigenvector matrix. In this paper, based on the performance index, a r obust observer design method is proposed for two-output systems where the o bserver gain can not be determined uniquely with respect to the desired obs erver poles. Utilizing the pole/zero locations of the observer dynamics, a step-by-step design procedure of the well-conditioned observer is developed . In addition, a new scaling method is developed with employing the eigenve ctor matrix as a scaling matrix. The proposed method is evaluated and compa red with the Kalman filter technique in a spindle-drive simulation example where the load speed needs to be estimated based on the measured signals.