The research in this paper introduces an algorithm for uniformly damping and stiffening structures using distributed actuators. Inherent in this algorithm is the ability to eliminate structural biases, which can cause steady state error. The method involves the utilization of modal techniques to calculate the proportional, integral, and derivative gains in a feedback control law. The gains are calculated by first converting the system into the modal domain, second by employing the principles of uniform damping and stiffening to the system in the modal domain, and finally by converting that system back into the physical domain. The beauty of this technique lies in the fact that even though the principles of modal control are used in gain setting, no modal information is needed in the fined control law. The theory is validated by simulations and is illustrated in an example. Since a modal approach and distributed actuation is utilized, the benefit to active control and adaptive structures is discussed.

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