A negative derivative feedback design algorithm

Vibration control logics based on the modal approach allow damping to be increased on a certain number of modes. The main limit associated with these strategies is represented by spillover on non-modelled modes. Negative derivative feedback (NDF) proves particularly robust against spillover since modal velocity is fed back through a band-pass filter so that undesired effects can be limited both at high and low frequencies. Unfortunately, the definition of the control gains for this logic is generally more difficult than other resonant controls owing to the lack of physical meaning. In this paper a design strategy for an NDF controller based on an optimal approach is proposed for single and multi-degrees of freedom systems and is tested on a cantilever beam finite element model.