From Adaptive Inverse Control


An extraordinary problem of great current interest is that of canceling noise in the passenger compartment of commercial aircraft. A new generation of airplanes is being developed using a combination of turbojet engines and propellers that promises to be 30 to 40 percent more fuel efficient than the best turbojet airplanes flying in the mid 1990s. The engines and pusher propellers will most likely be mounted at the tail. A serious drawback is the increase in cabin noise resulting from the use of propellers. We propose to utilize adaptive inverse control systems of the MIMO type to control and cancel noise due to the turbojet engines and the propellers.

Referring to Fig. 10.22(a), we see the aircraft with a turbine-driven propeller at the rear. We assume that there will be two engines and two propellers, and that they will be synchronized. Thus, obtaining a single reference signal from a sensor on the shaft of one of the engines should be sufficient. We will need to obtain signals corresponding to the fundamental and harmonics of the turbine blades, and the fundamental and harmonics of the propeller blades. A single reference signal containing a...

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Topics of Interest

10.7 SUMMARY In this chapter, means of describing linear multiple-input multiple-output (MIMO) systems have been developed. Block diagrams and flow graphs are useful for this purpose, as are algebraic...

Plant Disturbance Canceling   8.0 INTRODUCTION Methods for controlling plant dynamics have been described in the previous chapters. These methods have no effect on plant disturbance, which would...

10.4 PLANT DISTURBANCE CANCELING IN MIMO SYSTEMS Plant disturbance canceling in SISO systems was described in Chapter 8. The same techniques can be utilized, with some modification, to cancel...

Pleasant Surprises   While developing the principal mathematical results of adaptive inverse control, we would come upon a result from time to time that seemed to us to be a pleasant surprise.

Adaptive LMS Filters   3.0 INTRODUCTION The theory of adaptive filtering is fundamental to adaptive inverse control. Adaptive filters are used for plant modeling, for plant inverse modeling, and...