The problem of active balancing of speed-varying rotors, whose dynamics are changing or hard to be known beforehand, is frequently encountered in many applications. This paper presents a new adaptive method for balancing speed-varying rotors with multi-plane active balancing devices. The new method utilizes the positive realness of the transfer function of the active balancing system. This paper first shows the positive realness of the active balancing system and combines it with a direct adaptive control design method. A set of simulations was conducted to show the validity of the developed control law. The simulation studies show that the new method works as expected and has potential impact on future active balancing control systems.

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