Closed-loop online harmonic vibration estimation in DC electric motor systems

In this article, an active vibration control technique for direct-current electric motors sub-jected to harmonic mechanical load torque is introduced. Formulae to compute uncertain parameters of amplitude, frequency and phase angle of harmonic torque disturbances for angular velocity reference trajectory tracking are proposed. Vibrating torque disturbances are actively suppressed by the control voltage input. Mathematical modelling based on vibrating systems is adopted for purposes of online parameter estimation of oscillating signals. In this fashion, accurate estimation can be performed using measurements of the output signal only. Online parameter estimation is extended for a class of controllable dy-namical engineering systems subjected to harmonic disturbances. Formulae for closed-loop online parameter estimation of harmonic vibrations on differentially flat linear dynamical systems of n degrees of freedom for efficient tracking of desired time-varying motion ref-erence profiles are then presented. Analytical and numerical results prove that proposed formulae can be used to accurately determine the parameters of unknown harmonic vibra-tions, which is an excellent feature for high-efficiency active vibration control strategies. (c) 2021 Elsevier Inc. All rights reserved.