Dino J. Rossetti

Control effort weighting in feedforward adaptive control systems

Active control of noise and vibration in large dimensional complex systems is generally accomplished with adaptive feedforward control algorithms based on the steepest descent optimization approach. This paper examines the effects of incorporating control effort weighting into the cost function that is minimized by an adaptive control algorithm. When the plant matrix is rank‐deficient, the least‐squares solution to which the control algorithm converges is nonunique. In such situations, the control signals can drift with no change in performance. Small amounts of uniform control effort weighting can enforce a unique solution at the expense of decreased performance. A nonuniform form of control effort weighting is introduced that yields a unique solution without a performance penalty. With ill‐conditioned systems, small amounts of effort weighting can provide significant reductions in the control signals with only a very small increase in residual error. A form of effort weighting is introduced for ill‐cond...

Commercial active noise control solutions for aircraft—A variety of approaches

Today’s aerospace market is placing increasing emphasis on reducing noise and vibration to enhance passenger comfort. Lord offers high‐performance active solutions for aircraft noise problems with its NVX active systems. There are currently over 50 Lord NVXTM Active Systems flying on a variety of aircraft around the world. These systems include active isolations sytems for the Cessna Citation X business jet, a pylon active structural control system for DC9 aircraft, and speaker‐based active noise control systems for corporate turboprops. While the systems share many commonalties, they represent a variety of different approaches to the individual noise problems of these aircraft. Each of these problems requires a solution optimally designed for the application. During the presentation, the system components and general operation will be discussed. The benefits and limitations of these approaches will also be covered. How each system was optimized for its specific application will also be discussed. Numerou...