Xiaojun Qiu – författare

Since the publication of the first edition, considerable progress has been made in the development and application of active noise control (ANC) systems, particularly in the propeller aircraft and automotive industries. Treating the active control of both sound and vibration in a unified way, this second edition of Active Control of Noise and Vibration continues to combine coverage of fundamental principles with the most recent theoretical and practical developments.What’s New in This EditionRevised, expanded, and updated information in every chapterAdvances in feedforward control algorithms, DSP hardware, and applicationsPractical application examples of active control of noise propagating in ductsThe use of a sound intensity cost function, model reference control, sensing radiation modes, modal filtering, and a comparison of the effectiveness of various sensing strategiesNew material on feedback control of sound transmission into enclosed spacesNew material on model uncertainty, experimental determination of the system model, optimization of the truncated model, collocated actuators and sensors, biologically inspired control, and a discussion of centralised versus de-centralised controlA completely revised chapter on control system implementationNew material on parametric array loudspeakers, turbulence filtering, and virtual sensingMore material on smart structures, electrorheological fluids, and magnetorheological fluidsIntegrating the related disciplines of active noise control and active vibration control, this comprehensive two-volume set explains how to design and implement successful active control systems in practice. It also details the pitfalls one must avoid to ensure a reliable and stable system.

Since the publication of the first edition, considerable progress has been made in the development and application of active noise control (ANC) systems, particularly in the propeller aircraft and automotive industries. Treating the active control of both sound and vibration in a unified way, this second edition of Active Control of Noise and Vibration continues to combine coverage of fundamental principles with the most recent theoretical and practical developments.What’s New in This EditionRevised, expanded, and updated information in every chapterAdvances in feedforward control algorithms, DSP hardware, and applicationsPractical application examples of active control of noise propagating in ductsThe use of a sound intensity cost function, model reference control, sensing radiation modes, modal filtering, and a comparison of the effectiveness of various sensing strategiesNew material on feedback control of sound transmission into enclosed spacesNew material on model uncertainty, experimental determination of the system model, optimization of the truncated model, collocated actuators and sensors, biologically inspired control, and a discussion of centralised versus de-centralised controlA completely revised chapter on control system implementationNew material on parametric array loudspeakers, turbulence filtering, and virtual sensingMore material on smart structures, electrorheological fluids, and magnetorheological fluidsIntegrating the related disciplines of active noise control and active vibration control, this comprehensive two-volume set explains how to design and implement successful active control systems in practice. It also details the pitfalls one must avoid to ensure a reliable and stable system.

A virtual sound barrier is an active noise control system that uses arrays of loudspeakers and microphones to create a useful size of quiet zone and can be used to reduce sound propagation, radiation, or transmission from noise sources or to reduce noise level around people in a noisy environment. This book introduces the history, principle, and design methods of virtual sound barriers first, and then describes recent progress in research on the systems. Two virtual sound barrier systems, i.e., planar virtual sound barrier system and three-dimensional virtual sound barrier system, are discussed including applications, limitations and future direction discussions.

A virtual sound barrier is an active noise control system that uses arrays of loudspeakers and microphones to create a useful size of quiet zone and can be used to reduce sound propagation, radiation, or transmission from noise sources or to reduce noise level around people in a noisy environment. This book introduces the history, principle, and design methods of virtual sound barriers first, and then describes recent progress in research on the systems. Two virtual sound barrier systems, i.e., planar virtual sound barrier system and three-dimensional virtual sound barrier system, are discussed including applications, limitations and future direction discussions.

Parametric array loudspeakers (PALs) are capable of generating highly directional audio beams from nonlinear interactions of intense airborne ultrasound waves. This unique capability holds great potential in audio engineering. This book systematically introduces the physical principles of acoustics waves generated by PALs, along with the commonly used and the state-of-the-art numerical models, such as the Westervelt model, the convolution directivity model, the Gaussian beam expansion method, and the spherical wave expansion method.The properties of sound fields generated by PALs are analyzed. Also analyzed are various phenomena including the reflection of acoustics waves generated by PALs from a surface, transmission through a thin partition, scattering by a rigid sphere, and propagation in rooms. Furthermore, the steering and focusing of acoustics waves generated by PALs and potential applications of PALs in active sound control are investigated. Finally, the implementation issues of hardware, signal processing techniques, measurement, and safety are discussed.The book is tailored to meet the needs of researchers in this field, as well as audio practitioners and acoustics engineers.