Model-Free Filter for Servo Drive Applications via Error Dynamics Diagonalization Technique

This paper presents a novel filtering solution for servo system applications to extract the speed and acceleration information from the imperfect angle measurement. The proposed solution forms a cascade-type structure without using plant information, including its structural and parameter information, with the following contributions: (a) an improved disturbance attenuation capability incorporating the nonlinearly structured filter gain into the extended state observer and (b) a simple performance tuning process that does not involve matrix algebra to determine the desired filtering gain due to the filtering error dynamics diagonalization by the pole-zero cancellation technique. Moreover, the closed-loop filtering dynamics are rigorously analyzed, and various experiments validate the feasibility of the proposed solution.