On the implementation of modal filters for control of structures

Active control of a flexible hub-beam system using optimal tracking control method

“…A useful and direct way to eliminate observation spillover is to place sensors on the nodes of unobserved modes so as to reduce the influence of unobserved modes. There are also some other techniques for eliminating observation spillover, e.g., pre-filters [20,21], augmented observers [22], and adding sufficiently large number of sensors on the beam [23].…”

Practical implementation of an acoustic-based modal filtering sensing technique for active noise control

“…In modal filtering a number of point measurements are filtered down into signals which are related to global quantities; vibration modes of a structure for example [7]. Modal filtering can then provide an avenue to balance the number of signals a controller seeks to minimise while at the same time seeking to maximise the accuracy of the global performance measure.…”

“…To measure the orthogonal signals accurately and also achieve a balance between the number of sensors and error signals sent to a controller, modal filtering has been used [7][8][9][10]. In modal filtering a number of point measurements are filtered down into signals which are related to global quantities; vibration modes of a structure for example [7].…”

“…In practice, some noise sources are structural, others are not. The structural approach to modal filtering has seen the use of shaped sensors [11,[13][14][15], accelrometors [7,9,12,[16][17][18][19][20][21] or pizeo patches [18,[22][23][24][25] implemented on rectangular panels with simply supported boundary conditions.…”

Deriving time-domain models of structural-acoustic radiation into free space

“…Modal filtering is a sensing and design technique originally developed for vibration control [1][2][3][4], where structural acceleration or velocity measurements are decomposed into a set of modal amplitudes before they are input to the control system. This same technique for sensing system design has also been extended for use in active noise control in recent years [5][6][7][8][9][10][11][12][13].…”