Adaptive Feed-Forward Control of Low Frequency Interior Noise

Thomas Kletschkowski is Privatdozent in the Department of Mechanical Enginieering of the Helmut-Schmidt-University/University of the Federal Armed Forces Hamburg.

Part I Introduction.- 1 Introduction to Interior Active Noise Control.- 1.1 Idea, Limit and Structure of Active Control Concepts.- 1.2 Remarks on Interior Noise and Active Control Approaches.- 1.2.1 Comments on the Interior Noise Problem.- 1.2.2 Comments on Active Control Approaches.- 1.2.3 A Qualitative Comparison of Active Control Approaches.- 1.3 Examples for Engineering Applications of Interior ANC.- 1.4 Objective of Book.- Part II The Mechatronic Background of Feed-Forward Active Noise Control.- 2 Comments on Signals and Systems.- 2.1 Comments on Signals.- 2.1.1 Classification.- 2.1.2 Characteristic Values and Functions.- 2.2 Comments on Systems.- 2.2.1 Definitions                .- 2.2.2 Transfer Behaviour of LTI-Systems.- 3 Dynamics of Basic System.-  3.1 Basic Field Variables.- 3.2 Acoustic Field Equations.- 3.3 Energy Density and Sound Intensity.- 3.4 One-Dimensional Enclosed Sound Fields.- 3.4.1 Free Vibrations in One-Dimensional Sound Fields.- 3.4.2 Forced Vibrations in One-Dimensional Sound Fields.- 4 Sensors for Active Noise Control.- 4.1 Acoustical Sensing by Condenser Type Microphones.- 4.2 Sound Intensity Measurement.- 4.2.1 Functional Principle of Sound Intensity Probes.- 4.2.2 Errors in Sound Intensity Measurements.- 4.3 Structural Sensing by Accelerometers.- 5 Actuators for Active Noise Control.- 5.1 Electro-Dynamical Loudspeakers.- 5.2 Electro-Dynamical Panel Speakers.- 6 Active Control of Tonal and Broadband Noise.- 6.1 Mathematical Preparation.- 6.1.1 Hermitian Matrices.- 6.1.2 Quadratic Optimization.- 6.1.3 Steepest-Decent Algorithm.- 6.2 Terms and Structure of Feed-Forward Control Approaches.- 6.3 Review and Evaluation of Control Strategies.- 6.3.1 Description of Benchmark System and Close Form Solution.- 6.3.2 Analysis of Specific Control Strategies.- 6.3.3 Comparison of Control Strategies.- 6.4Multi-channel Control of Tonal Noise.- 6.4.1 Optimal Control of Tonal Noise.- 6.4.2 Adaptive Control of Tonal Noise.- 6.5 Active Control of Tonal Noise with Modified Cost Functions.- 6.5.1 Optimal Control Using a General Cost Function.- 6.5.2 Remote Sensor Control.- 6.5.3 Parametric Controller Design.- 6.6 Multi-channel Control of Stochastic Disturbances.- 6.6.1 Optimal Control of Stochastic Disturbances.- 6.6.2 Adaptive Control of Stochastic Disturbances.- 6.7 A Very Short Note on Adaptive Feedback Control.- Part III ANC-System Design: Theory.- 7 ANC-System Design Tools.- 7.1 Numerical Analysis of Sound Fields.- 7.1.1 A Short Overview on Numerical Methods.- 7.1.2 The Finite Element Method.- 7.2 Inverse Noise Source Identification.- 7.2.1 A Note on Source Identification Methods.- 7.2.2 The Inverse Finite Element Method.- 7.3 Initial Performance Estimation.- 7.3.1 Coherence Analysis.- 7.3.2 Transducer Placement Analysis.- 7.3.3 Correlation Analysis.- 7.3.4 Impulse Response Analysis.- 7.3.5 A Short Comparison of Initial Performance Estimators.- 7.4 Two Short Remarks on the Effect of Sampling Frequency.- 8 ANC-System Design Methodology.- 8.1 A Note on the Design Methodology for Mechatronic Systems.- 8.2 System Maturity Levels.- 8.3 A Design Methodology for ANC-Systems.- 8.3.1 ANC-System Design Tasks.- 8.3.2 ANC-System Design Steps.- 8.3.3 Matrix Model of the ANC-System Design Process.- Part IV ANC-System Design: Examples.- 9 Active Noise Control in a Semi-Closed Interior.- 9.1 Description of Problem and Requirements.- 9.2 Feasibility Study on ANC for the MA WA.- 9.2.1 Noise Field Analysis for the MA WA.- 9.2.2 Formulation of ANC-System Concept for the MA WA.- 9.2.3 Proof of MA WA ANC-System Concept.- 9.3 First Specification of Active Noise System.- 9.3.1 First Specification of Microphones.- 9.3.2 First Specification of Actuators.- 9.3.3 First Specification of Controller Software.- 9.3.4 Evaluation of First Specification.- 9.4 Weight, Cost and Efficiency Study.- 9.4.1 Actuator Design for ANC in the MA WA.- 9.4.2 Improvement of Adaptive Signal Processing.- 9.4.3 Optimization of Sensor and Actuator Locations.- 9.5 Sensitivity Study for ANC in MA WA.- 9.6 Robust Control of Sound in the MA WA.- 9.6.1 Design, Construction and Verification of Relevant Test Rig.- 9.6.2 Determination and Modelling of Uncertainties.- 9.6.3 Review of the MA WA Robust Control Approach.- 9.7 Design Process Summary.- 10 A Sound Intensity Probe with Active Free Field.- 10.1 Feasibility Study on an Active Intensity Probe.- 10.1.1 Analysis of the Controlled Sound Field.- 10.1.2 Formulation of SIAF-System Concept.- 10.1.3 Controller Design and Proof of SIAF-System Concept.- 10.2 First Specification of an Active Intensity Probe.- 10.2.1 First Specification of System Hardware.- 10.2.2 Test of First SIAF-Specification.- 10.3 Design Process Summary and Outlook.- 11 Active Noise Control Around Human Head.- 11.1 Feasibility Study on Local ANC in Bedrooms.- 11.1.1 Description of Bedroom Test Rig.- 11.1.2 Noise Field Analysis in the Transmission Test Rig.- 11.1.3 Anti-Noise Field Analysis in the Transmission Test Rig.- 11.1.4 Comments on Domain-Specific Design for Broadband ANC.- 11.1.5 System Integration and Functional Testing of Local ANC.- 11.1.6 Summary of Feasibility Study.- 11.2 Comments on the Application of Virtual Microphones.- 12 Active Noise Control and Audio Entertainment.- 12.1 Aircraft Interior Noise and ANC with Audio Entertainment.- 12.1.1 Comments on Aircraft Interior Noise.- 12.1.2 Comments on Hybrid ANC-Audio Systems.- 12.2 Feasibility Study on a Very Light Jet ANC-Audio System.- 12.2.1 In-Flight Measurements and Noise Field Analysis.- 12.2.2 Anti-Noise Field Analysis using a VLJ Mock-Up.- 12.2.3 Design of the ANC-Audio Controller.- 12.2.4 Integration and Test of the ANC-Audio Controller.- 12.2.5 ANC-Audio System Design Process Summary.- 13 Noise Source Localization in an Aircraft Cabin.- 13.1 Acoustic Ground Tests in an Aircraft Cross-Section.- 13.1.1 Description of the Aircraft Mock-Up.- 13.1.2 Description of Ground Test Experiments and Results.- 13.2 Inverse Calculation for an Aircraft Cross-Section.- 13.3 IFEM Application Summary.- Part V Summary.- References.- Index.