Compensation of mode shapes with a piezo electric actuator for an optical drive

In miniaturized systems (e.g. optical disk drives) much effort is made to design a structure in such a way that the demands on dimensions (height, width) and desired bandwidth are satisfied. Easier, and often cheaper designs can not be used, because they suffer from lower resonance frequencies, which limit the bandwidth. A method is presented for mechatronic structures that compensates unwanted bandwidth limiting resonance frequencies with an additional piezo electric actuator. Advantage of this method is that no extra sensor is used and that the contribution of the piezo is much easier to tune (when compared to a notch filter), since it is part of the structure. Disadvantage is that the piezo influences the dynamics of the original system, which complicates the choice of a suitable piezo actuator.