System and method for manipulating the spectral composition and / or reducing the acoustic power emitted by a source

Abstract

The invention relates to a system and a method for manipulating and / or reducing the spectral composition of a first acoustic power emitted by an acoustic source. The object of the invention is to eliminate the disadvantages of the prior art and to provide a system by means of which the emitted acoustic power of an acoustic source can be manipulated and / or reduced. This problem is solved by the features listed in the claims.

Description

[0001] The invention relates to a system and a method for manipulating and / or reducing the spectral composition of a first acoustic power emitted by an acoustic source.

[0002] A related method and system for actively reducing the noise emissions of jet engines is disclosed, for example, in German patent application DE 101 35 566 A1. In this system, a sound field is measured using a plurality of sensors. This sound field consists of a primary sound field and a secondary sound field superimposed on it for noise reduction. Actuators are controlled to generate the secondary sound field by means of a control device, which minimizes the measured sound field based on a known transfer function between the actuators and the sensors. Several vibration modes are determined from the sound field, and their amplitudes are used as input for the control device. Description of the invention

[0003] The object of the invention is to eliminate the disadvantages of the prior art and to provide a system by means of which the emitted acoustic power of an acoustic source can be manipulated and / or reduced.

[0004] This problem is solved by the features listed in the claims.

[0005] A system for manipulating and / or reducing the spectral composition of a first acoustic power P emitted by an acoustic source S is described. S provided, whereby the first acoustic power P S a first acoustic intensity field I S,i forms. The system according to the invention comprises N sound intensity actuators A1,A2, ...,A n ,A N on, where each of these sound intensity actuators A1, A2, ..., A n ,A N each with a distance R S,1 ,R S,2 , ...,R S,n ,R S,Nand a radiation direction around the source S, but within a virtual surface C S , is arranged. Furthermore, each of the N sound intensity actuators A1,A2, ...,A n ,A N set up to create a second acoustic intensity field defined in amplitude, frequency and phase I→A,1, I→A,n until I→A,n with a second acoustic power P A to generate. The system according to the invention further comprises M sound intensity probes I 1 , I 2 , ..., I m , I M on, which are arranged on the virtual surface Cs, wherein the M sound intensity probes I 1 , I 2 , ..., I m , I M in each of the K axis directions, the component of an incident intensity vector projected onto the respective axis direction I→Sm measure. An electronic signal processing and active control device is designed to measure the total emitted acoustic power P, formed from the first acoustic power P. S the source S and the second power P A the N sound intensity actuators are manipulated or minimized.

[0006] According to various embodiments, the acoustic source S is composed of L individual acoustic sources.

[0007] The emitted first acoustic power P S is preferably formed from a first active acoustic power P S_active or a reactive performance P S_reactive or a sum of both according to P S = P S_active + j · P S_reactive (with j 2 = -1 imaginary unit).

[0008] Furthermore, the emitted first acoustic power P S the integral of the intensity I of the source S S,i (C s) via the virtually conceived surface C S .

[0009] According to various design variants, the N sound intensity actuators are A1,A2, ...,A n ,A N within the area defined by C S a limited area is distributed using a probabilistic method, preferably using a Poisson-Disc Sampling method.

[0010] A spatial orientation (rotational position) of the N sound intensity actuators A1,A2, ...,A is preferred. n ,A N can be determined by means of a predetermined probability distribution, preferably a Poisson distribution or a Gaussian distribution.

[0011] According to various design variants, the N sound intensity actuators are A1, A2, ...,A n ,A N Controllable systems, preferably with which an acoustic intensity field defined in amplitude, frequency and phase is generated. I→A,1,I→A,2,⋯,I→A,n,I→A,N The sound intensity is generated individually by each of these sound intensity actuators. The adjustable systems can be, for example, loudspeakers, underwater loudspeakers, and / or structure-borne sound transducers. The use of other adjustable systems is also conceivable.

[0012] According to various embodiments, each sound intensity probe I 1 , I 2 , ···, I m , I M on each surface segment C S,1 , C S,2 , ···,C S,m , C S,M arranged 1 , I 2 , ···, I m , I M can be uniaxial (one-dimensional), biaxial (two-dimensional), triaxial (three-dimensional) or multiaxial (multi-dimensional).

[0013] Furthermore, according to various embodiments, the M sound intensity probes are sensors or sensor combinations for measuring acoustic active and reactive intensity. Preferably, the M sound intensity probes are pu probes and / or pp probes.

[0014] Furthermore, the system according to the invention can include reference sensors, wherein the number of reference sensors corresponds to the number L of individual sources. The reference sensors can also be configured to measure quantities that are directly related to the acoustic emission of the source S. Preferably, the L reference sensors are intensity probes, microphones, accelerometers, velocity sensors, displacement sensors, pressure sensors, hydrophones, rotational speed sensors, and / or laser vibrometers. The use of reference sensors other than those mentioned here is conceivable.

[0015] To solve the problem, a method for manipulating the spectral composition and / or reducing the acoustic power P emitted by a source S is also required. S by means of a system for manipulating and / or reducing the spectral composition of a first acoustic power P emitted by an acoustic source S S The procedure is provided. It comprises the following steps: a. Defining an envelope area C S , which is a virtual, physically non-existent, area for accounting for the first acoustic power P emitted by the source S S , where the enclosing surface C S the source S completely encloses, b. Arrangement of M intensity probes I 1 , I 2 , ..., I m , I M on surface C S , where each of the M intensity probes I 1 , I 2 , ..., I m , I Ma sub-area segment C S,1 , C S,2 , ···,C S,m , C S,M the envelope area C S is assigned c. Measuring an incident first intensity vector I→Sm (with I→S,1m, I→S,km to I→S,Km Axis directions) using the M intensity probes and determination of its components of I→Sm(I→S,Xm,I→S,Ym and I→S,Zm) with respect to a reference coordinate system and measuring an incident second intensity vector I→Am(with I1m,Ikm to IKm) axis directions) using the M intensity probes and determining its components of I→Am(I→A,Xm,I→A,Ym and I→A,Zm) with regard to a reference coordinate system. In the case that only the (noise) source or only the actuators are switched on, for example, only I→Sm or only I→Am can be determined. In the case where both are "activated", the superimposed field is measured (superposition principle). d. Calculating the first acoustic power P S , by summing individual first acoustic partial powers P S,m , which extend over the sub-area segments C S,m are emitted, and by means of PS,m=∫CS,mI→Sm⋅n→Om⋅dA to be calculated, whereby n→Om The surface normal vector is used to calculate a second acoustic power P. A of N sound intensity actuators A1, A2, ..., A n , A N "by summing individual second acoustic partial powers P" A,m , which extend over the sub-area segments C S,m are emitted, and by means of PA,m=∫CS,mI→Am⋅n→Om⋅dA to be calculated, whereby n→Om is a surface normal vector. e. Active control of the system by means of a control system, such that a total emitted acoustic power P, formed from the first acoustic power P S the source S and the second acoustic power P A The N sound intensity actuators are manipulated or minimized according to: P=∑m=1MPm, where Pm=∫CS,m(I→Sm+I→Am)⋅n→Om⋅dA=∫CS,mI→Tm⋅n→Om⋅dA=PS,m+OA,m, where P m The determined total power of an intensity probe or the partial sound power on a surface segment corresponds to the control parameters q for the N sound intensity actuators A1, A2, ..., A. n , A N will be based on P, P m or weighted sizes of P or P m The control parameters q are determined and these control parameters are sent to the N sound intensity actuators A1, A2,..., A n , A Ntransmitted in order to determine the emitted acoustic first power P using these control parameters q S to manipulate and / or reduce. This affects the superimposed total field of I→Am and I→Sm on area C S,m (or a partial area) is manipulated, thus manipulating the total radiated acoustic power.

[0016] Each surface segment C is given preference S,1 , C S,2 , ···,C S,m , C S,M a surface normal vector n→O1,n→O2,⋯,n→Om,n→OM assigned, whereby it is true that n→O1,n→O2,⋯,n→Om,n→OM constant over the respective, assigned area segment C S,1 , C S,2 , ···,C S,m , C S,M is.

[0017] Furthermore, the envelope area C is preferred. S for the division into area sub-segments C S,1 , C S,2 , ···,C S,m , C S,Mdiscretized with the assumption that acoustic state variables, in particular sound pressure, particle velocity, density and / or temperature, are to a first approximation constant over all surface sub-segments C S,m are.

[0018] Furthermore, the problem is solved with a control method for controlling the system according to the invention and / or in a method according to the invention, wherein control parameters q for the N sound intensity actuators A1, A2, ..., A n ,A N The following procedural steps will be used to determine this: a. Performing a system identification, whereby the transfer function G (in the frequency domain) between the N sound intensity actuators A1, A2, ..., A n ,A N and the partial powers P measured by the sound intensity probes A,m , where a G-matrix is ​​determined to determine the transfer functions, and b. Calculation of the control parameters q of the N sound intensity actuators A1, A2, ..., A n ,A N by solving a system of equations according to e=PS,X+G⋅q−PX,set=PX*+G⋅q=0 using the transfer function G, such that an error signal e is minimized or becomes zero, where P S,X P S,m , P S,m,weight , P S,weight or P is and P X,soll a target value for P S,m , P S,m,weight , P S,weight The separation P A and P S This is not done in the regulation presented here, as only the superimposed field is measured. However, P corresponds to A the secondary power generated by G*q.

[0019] The transfer function Z between the N sound intensity actuators and the L acoustic sources or L reference sensors and / or the transfer function H between the first acoustic source S, composed of up to L sub-sources or detected via L reference sensors, and the measured acoustic partial powers P is also preferred in the control method according to the invention. S,m or P S,m,weight , where a Z-matrix and an H-matrix are determined for each of the transfer functions Z and H. These are primarily determined and used for the utilization of a feedback path (more details on this can be found in the Fig. 7d i explained).

[0020] Depending on the implementation, the control procedure is carried out using a Single Input - Single Output (SISO) method, a Single Output - Multiple Expansion (SISO-ME) method, a Single Input - Multiple Output (SIMO) method, or a Multiple Input - Multiple Output (MIMO) method, which will be explained in more detail later.

[0021] The control procedure is operated according to various implementation variants. a. without reference sensors (feedback operating mode) or b. with reference sensors (feedforward operating mode) or c. without reference sensors but with a synthetic reference signal generated by the control system (hybrid operating mode).

[0022] Preferably, the control parameters q for the actuators are calculated based on the error signals by a. an FBFxLMS algorithm using either Tikhonov regularization or Moore-Penrose pseudoinverses, where the regularization depends on the problem being formulated: If fewer actuators than intensity probes are used, then the Moore-Penrose pseudoinverse is preferred. Conversely, if there are many actuators and fewer intensity probes, regularization or a singular value decomposition (SVD) variant is preferred. b. or by a mapped FBFxSVD algorithm using singular value decomposition (SVD), truncated SVD (TSVD) and / or in combination with regularization according to Thikonov or a comparable method, such as Lasso.

[0023] Furthermore, a control method for the general application of the FBFxSVD or FxSVD method in control structures is disclosed, whereby these methods are transferable to any linear problems of the form A · x = b for which a real-time solution for x is sought. In particular, the transferability to classical ANC problems for minimizing sound pressure using the LMS method, as well as in SIMO and MIMO systems, is mentioned. Implementation of the invention

[0024] The invention will be explained in more detail using one or more exemplary embodiments. For this purpose, we will show... Fig. 1 Basic configuration of the system for determining the acoustic power S, Fig. 2 Basic configuration of the system with sound field actuators, Fig. 3 Basic configuration of the system with sound field actuators with main radiation direction towards the acoustic source, Fig. 3b Basic configuration of the system with sound field actuators with main radiation direction away from the acoustic source, Fig. 4 Basic configuration of the system with intensity probes Fig. 5. Setup of the intensity probes, Fig. 6 Basics of SPCS control, Fig. 7a Block diagram: FxLMS, Fig. 7b Block diagram: FxSVD, Fig. 7c Ratio of computation speeds between FxLMS and FxSVD for different numbers of sound intensity actuators, Fig. 7d Block diagram: Feedback Cancellation FxLMS (FBFxLMS), Fig. 8 Block diagram of system identification with determination of matrix G, Fig. 9 Block diagram of system identification with determination of matrix Z, Fig. 10 Block diagram of system identification with determination of matrix H, Fig. 11 Block diagram of an SPCS system with FBFxLMS-based control Fig. 12 Block diagram of an SPCS system with FBFxLMS-based control hybrid Fig. 13 Block diagram of an SPCS system with FxLMS-based feedback control Fig. 14 Representation of 3D intensity vectors measured on the basis of the hydroacoustic radiation by a ship propeller a) Top view and b) Side view Fig. 15. Illustration of the determination of the location of the minimum distance between 2 skew lines. Figure A01 Single configuration of the SPCS system for use in a pipeline Figure A02 Arrangement of the sound intensity probes when using the SPCS system in pipelines Figure A03 Dual configuration of the SPCS system for use in pipelines,

[0025] The description refers to the accompanying drawings, which illustrate specific embodiments in which the arrangement according to the invention can be implemented. In this respect, directional terminology such as "top," "bottom," etc., is used with reference to the orientation of the described drawings. This directional terminology serves for illustrative purposes and is in no way restrictive.

[0026] It is understood that other embodiments may be used and structural or logical modifications made without deviating from the scope of protection of the present invention. It is understood that the features of the various exemplary embodiments described herein may be combined with one another, unless specifically stated otherwise. The following detailed description is therefore not to be interpreted as limiting, and the scope of protection of the present invention is defined by the appended claims.

[0027] In the figures, identical or similar elements are provided with identical reference symbols where appropriate. 1. Basic structure of the SPCS system

[0028] The present invention describes a system (SPCS - Sound Power Control System) with which the acoustic power P emitted by an acoustic source S can be controlled. Sits spectral composition can be manipulated and / or reduced. The acoustic source S is to be understood as a compact source composed of L individual acoustic sources. The acoustic power P S The acoustic energy W, which results from the acoustic energy emitted per unit time (Eq. 1), is fundamentally responsible for the formation of all other essential acoustic field quantities, such as acoustic pressure p and velocity v. i or the intensity I iThis relationship is described in Eq. 1. The acoustic energy W consists of a potential and a kinetic energy component. ρ0 is the fluid density without an acoustic field, or is called the rest density, c is the speed of sound at which disturbances propagate in the fluid, and ρ is the local fluid density in the acoustic field. The subscript i represents the directions with respect to the chosen coordinate space or the global coordinate system GCS / 7. Furthermore, the Einstein summation convention applies. ||∗|| 2 represents the Euclidean norm. W=Wpot+Wkin =12∫V(p2ρ0⋅c2+ρ⋅‖vi‖22)dV with i=1,2,3 or x,y,z

[0029] The emitted acoustic power P S / 4 of source S / 1 is now for the formation of intensity field I S,i / 2 responsible and can be expressed as the integral of intensity I S,i (C S ) / 5 about the virtually conceived surface C S / 3 are represented; Eq. 2. The area C S The source S must be completely enclosed, or in the general case, in the mathematical sense, it must be closed. PS=∫CS(IS,i(CS)⋅nO,i(CS))dA with i=1,2,3 or x,y,z

[0030] I S,i (C S ) are the components of the acoustic intensity vector on C S and the components n O,i (C S ) / 6 of the surface normal vector on C S (Eq 2).

[0031] If the acoustic field quantities are defined in the complex number space ℂ, then the components of the intensity vector I can be S,i as a sum of active I S_active,i and reactive component I S_reactive,i represented; Eq. 3. In Eq. 3, j represents the imaginary unit, with j 2 = -1. IS,i=IS_active,i+j⋅IS_reactive,i

[0032] According to Eq. 3, the acoustic power can therefore also be represented as the sum of active and reactive components. PS=IS_active+j⋅PS_reactive

[0033] The acoustic power P S The emission emitted by S is an integral, distance-invariant quantity. This means that it is independent of the size and shape of the surface C. S , taking into account the above requirement for C SThe acoustic power is always constant. With regard to the active manipulation of the spectral composition and / or the reduction of the acoustic power emitted by source S by a control system, it can be considered a significant advantage that this is based on a distance-invariant quantity. All other relevant acoustic field quantities are distance-dependent with respect to the underlying acoustic source. The second advantage of the invention lies in the fact that the control system is based on an acoustic energy quantity, in this case, the acoustic power or intensity. If the acoustic energy quantities are manipulated or, if necessary, reduced, this automatically also affects other acoustic field quantities, such as the acoustic pressure p. SThe crucial point and advantage of this invention is that the reverse is not true. Another crucial advantage of this invention is that acoustic sources outside of C S have no influence on the SPCS control system. This can be explained by the fact that for all acoustic sources outside of C S , Eq. 2 becomes identically zero. The fourth decisive advantage lies in the fact that, knowing all components of I S,i (C S ) always also provides directional information regarding the acoustic source S.

[0034] To control the acoustic power emitted by S, A1 - A N Sound intensity actuators 8 are arranged around S. Preferably, the actuators are positioned with their main radiation direction towards the acoustic source, as shown in Fig. 3 shown, aligned. Alternatively, the actuators can also be aligned with their main radiation direction, as shown in Fig. As shown in 3b, they should be oriented away from the source. In the general case, the actuators can be located within the area defined by C. S The limited area is preferably distributed using the Poisson disc sampling method or another probability-theoretically motivated method. The spatial orientation (rotational position) of the actuators, defined by three rotation angles (Euler angles) of the main radiation direction relative to the directions of the GCS / 7 ( Fig. 1 to Fig. 5), is also determined by means of a predetermined probability distribution, preferably a Poisson distribution or alternatively another distribution such as a Gaussian distribution.

[0035] The positions of the individual actuators are defined with respect to the global coordinate system GCS / 7 ( Fig. 2) defined and have distances of 9 (R) to the center of the acoustic source S or any other arbitrary reference point. S,1 , R S,n to R S,N ) ( Fig. 2).

[0036] All controllable systems capable of generating an acoustic intensity field defined in amplitude, frequency and phase can be used as sound intensity actuators. (I→A,1,I→A,n to I→A,N) ( Fig. 3 and Fig. 3b) can be generated individually by each sound intensity actuator 8. Preferably, loudspeakers, underwater loudspeakers, structure-borne sound transducers or comparable systems are used for this purpose.

[0037] To build the SPCS control system, the virtual surface C is now used. S multi-axis intensity probes 15 (I 1 , I m to I M ) ( Fig. 4) arranged. Within the SPCS system, preferably pu probes, pp probes, or any other type of sensor or sensor combination can be used to measure the acoustic active and reactive intensity. For example, if acoustic intensity probes based on the pp principle are used, the axes of the intensity probes can be constructed from at least two microphones, two hydrophones, or two pressure sensors spaced Δr apart. Any other combination of two sensors for the simultaneous measurement of acoustic pressure and determination of the spatial acoustic pressure gradient can also be used. Likewise, any sensor combination that simultaneously measures the acoustic pressure p and the components of the acoustic velocity v can be used. i or can measure the component projected in a specific direction. The positions of the individual intensity probes are given in the coordinates of the GCS / 7 ( Fig. 1 to Fig. 5) defined and have distances of 14 (R) to the center of the acoustic source or any other reference point. SI,1 , R SI,m to R S1,M ) ( Fig. 4). The individual probes are assigned the surface sub-segments 11 (C S,1 , C S,M up to C S,M ) ( Fig. 4) with the respective surface normal vectors 12 (n→O1,n→Om to n→OM) ( Fig. 4) assigned. Eq. 5 shall apply here. CS=∑mMCS,m

[0038] In the technical implementation of the invention, the continuous sub-areas C S,1 , C S,m up to C S,M approximated in a discretized form, whereby n→O1, n→Om until n→OM are constant across the respective sub-areas. Within the SPCS control core, the area sub-segments C S1 , C S,M up to C SM as well as the surface normal vectors n→O1, n→Om until n→OM, which regarding the GCS / 7 ( Fig. 1 to Fig. 5) are defined and stored electronically.

[0039] The individual m intensity probes measure with I1m, Ikm until IKm the portion of the incident intensity vector projected onto the respective axis direction I→Sm / 15e. In the concrete technical implementation of the invention, 1D intensity probes 15a, 2D intensity probes 15b, 3D intensity probes 15c or intensity probes with more than 3 axis directions 15d can be used.

[0040] When using 1D intensity probes 15a, the probe axis is surface normal on the subsurface C. S,m to orient. When using 2D intensity probes 15b, the plane spanned by the two probe axes is surface normal on the subsurface C. S,mto orient. The orientation of the axes in which the measurement of the projected proportion of I→Sm on area segment C S,m This is achieved through the direction vector n→I,1m,n→I,km to n→I,Km 15e described. The superscript m denotes the probe position or number, the subscript k the probe axis under consideration. Within the SPCS control kernel, the direction vectors n→I,1m,n→I,km to n→I,Km The individual probe axes with respect to the defined GCS are electronically stored. [I1S,mI2S,mI3S,mIkS,mIKS,m]=[nI,1,XmnI,1,YmnI,1,ZmnI,2,XmnI,2,YmnI,3,ZmnI,3,XmnI, 3,YmnI,3,ZmnI,k,XmnI,k,YmnI,k,ZmnI,K,XmnI,K,YmnI,K,Zm]⋅[IS,XmIS,YmIS,Zm]=nm__⋅I→Sm (n__mT⋅n__m+ΓT⋅Γ)⋅I→Sm=n__mT⋅I→S,m;with Γ=γ⋅[100010001] I→Sm+(n__mT⋅n__m+ΓT⋅Γ)−1⋅n__mT⋅I→S,m γ>0 for K=2; γ≥0 for K≥3; for K=1 it follows directly I→Sm =I→S,m⋅n__m

[0041] In the technically implemented SPCS system, the components projected onto the probe axis directions are now measured at the probe position m. I1S,m, IkS,m until IKS,m of the complete intensity vector I→Sm on C S,m , which is defined with respect to the coordinates of GCS 7, measured. The goal now is to determine the components of I→Sm, in detail IS,Xm,IS,Ym and IS,Zm, to determine the GCS. This can be achieved by solving the system of equations Eq. 6. Formally, Eq. 6 is first transformed into Eq. 7 using a Tikhonov regularization, from which the general solution according to Eq. 8 is then obtained. The choice of the regularization parameter γ depends on the number of probe axes K with which the projected components of I→Sm on sub-area C S,MThe possible configurations for choosing γ, depending on K, are described in Eq. 9. For the special case K = 1, the work continues directly with the measured projected intensity components. The calculation of the individual acoustic partial powers P S,m / 13 ( Fig. 4) which cover the sub-areas C S,M The emissions can be calculated using Eq. 10. PS,m=∫CS,mI→Sm⋅n→Om⋅dA

[0042] The total emitted acoustic power P S is calculated by summing the partial services according to GL.11. PS=∑m=1MPS,m

[0043] The regulation within the SPCS system is based either on the acoustic partial powers according to Eq. 10, the total power according to Eq. 11, or also on the weighted acoustic partial powers P. S,m,weight according to Eq. 12 or the weighted total performance according to Eq. 13. The individual weighting factors w mare preferably specified by the user of the SPCS system and stored electronically within the SPCS control system. PS,m,weight=PS,m⋅wm;with ∑m=1Mwm=1 PS,weight=∑m=1MPS,m,weight

[0044] In the preceding description of the mathematical basis of the SPCS system, equations 1 to 13 have always been described from the perspective of the acoustic source S. These are referred to as primary quantities in the following. However, with active control by the SPCS system, acoustic power components are also generated or emitted by the sound intensity actuators. These are referred to as secondary quantities in the following. Equations 2 to 13 can also be formulated without loss of generality with respect to the acoustic emissions from the actuators of the SPCS system and are given the subscript A (equations 14 to 24). PA=∫CS(IA,i(CS)⋅nO,i(CS))dA with i=1,2,3 or x,y,z IA,i=IA_active,i+j⋅IA_reactive,i PA=PA_active+j⋅PA_reactive [I1A,mI2A,mI3A,mIkA,mIKA,m]=[nI,1,XmnI,1,YmnI,1,ZmnI,2,XmnI,2,YmnI,3,ZmnI,3,XmnI, 3,YmnI,3,ZmnI,k,XmnI,k,YmnI,k,ZmnI,K,XmnI,K,YmnI,K,Zm]⋅[I,XmIA,YmIA,Zm]=nm__⋅I→Am (n__mT⋅n__m+ΓT⋅Γ)⋅I→Am=n__mT⋅I→A,m;with Γ=γ⋅[100010001] I→Am=(n__mT⋅n__m+ΓT⋅Γ)−1⋅n__mT⋅I→A,m γ>0 for K=2; γ≥0 for K≥3; for K=1 it follows directly I→Am =I→A,m⋅n__m PA,m=∫CS,mI→Am⋅n→Om⋅dA PA=∑m=1MPA,m PA,m,weight=PA,m⋅wm;with ∑m=1Mwm=1 PA,Weight=∑m=1MPA,m,weight

[0045] Within the SPCS system, active control is achieved by manipulating or minimizing the superimposed primary acoustic power parameters of the source S and the secondary power parameters of the N sound intensity actuators, i.e., the total emitted acoustic power. Pm=∫CS,m(I→Sm+I→Am)⋅n→Om⋅dA=∫CS,mI→Tm⋅n→Om⋅dA=PS,m+PA,m P=∑m=1MPm Pm,weight=Pm⋅wm;with ∑m=1Mwm=1 Pweight=∑m=1MPm,weight 1.1 Control procedures of the SPCS system

[0046] The SPCS system can be controlled using four different methods. The specific method employed depends on the characteristics of the acoustic source S. These characteristics include, for example, the spatial radiation pattern (symmetrical, asymmetrical) and the temporal characteristics of the acoustic radiation. The latter describes whether the radiation pattern of S is intermittent or constant over time. The following section presents the control methods achievable with the SPCS system, outlining their advantages and disadvantages. When discussing these advantages and disadvantages, computation time and complexity are considered only as secondary criteria. Control method 1: Single Input - Single Output (SISO) Input=P or Pweight Output = A single control signal for all N actuators. Target criterion: Minimization of the total acoustic power P via C S is emitted. Advantages: Simple and stable control for stationary acoustic sources with symmetrical radiation characteristics. Disadvantage: Problematic with intermittent symmetrical / asymmetrical radiation characteristics. Control Method 2: Single Output - Multiple Expansion (SISO-ME) Input=P or Pweight Output = A uniform output signal which is converted outside the SPCS control loop into the individual control signals of the N actuators according to fixed criteria.

[0047] Target criterion: Minimization of the total acoustic power P via C S is emitted.

[0048] Advantages: Simple and stable control, as the SPCS control works in the SISO method, for stationary acoustic sources with asymmetrical radiation characteristics.

[0049] Disadvantage: Problematic with intermittent radiation characteristics. Control Method 3: Single Input - Multiple Output (SIMO) Input=P or Pweight Output = an individual control signal for each of the N actuators

[0050] Target criterion: Minimization of the total acoustic power P via C S is emitted

[0051] Advantages: Suitable for sources with intermittent, asymmetrical radiation characteristics. More stable control than variant 4, as it regulates the total integral power.

[0052] Disadvantage: More complex control algorithms than variants 1 and 2, and the possibility of control instabilities occurring. Control method 4: Multiple Input - Multiple Output (MIMO) Input=Pm or Pm,weight Output = an individual control signal for each of the N actuators

[0053] Target criterion: Minimization of the acoustic partial power P m the individual C S,M be emitted.

[0054] Advantages: Suitable for sources with intermittent, asymmetrical radiation characteristics. Individual control of all intensity actuators to minimize the individual acoustic power levels P. m on C S,m .

[0055] Disadvantage: More complex control algorithms than variants 1, 2 and 3, and the possibility of control instabilities occurring.

[0056] For further explanation of the SPCS regulation, reference is made to the following general descriptions in Fig. 6. Here, we assume a compact acoustic source S, which can be understood as a combination of up to L individual sources. In the practical implementation of SPCS, precise knowledge of L is irrelevant.

[0057] The acoustic source S is responsible for the emission of the acoustic power P. S via C S or for the emission of P S,m via C S,m responsible. Furthermore, there are N sound intensity actuators that control the acoustic power P. A via C S or the partial services P A,m via C A,m , measured by M acoustic intensity probes, emit.

[0058] GE ℂ M×N is the transfer function between the acoustic power quantities P A,m or P A,m,weightand the control signals of the sound intensity actuators. It should be noted that from this point forward, only transfer functions will be discussed. Depending on whether the control core of the SPCS system operates in the frequency domain or the time domain, G represents the transfer function in the frequency domain or the impulse response in the time domain.

[0059] The acoustic performance parameters P are used in the control loop of the SPCS system. A or P A,weight If G is worked, it reduces to G ∈ ℂ 1×N The complex vector q ∈ ℂ N×1 describes the source strengths of the sound intensity actuators.

[0060] ZE ℂ L×N describes the transfer functions between the N sound intensity actuators and the L acoustic sources. s ∈ ℂ L×1 Here, is the complex vector of acoustic source strengths. Z ∈ ℂ L×NThe values ​​of the reference sensors (L and N) are usually not directly known in the practical implementation of SPCS, but can only be determined indirectly via one or more reference sensors. Z represents the transfer functions between L reference sensors and N sound intensity actuators, and s represents the source or signal strength of the reference sensors. The reference sensors are preferably positioned close to the acoustic source S to guarantee a high correlation or coherence between the acoustic signal of the source S and the reference sensor signals. Any type of sensor capable of measuring quantities directly related to the acoustic emission of the source S can be used as a reference sensor. These preferably include microphones, intensity probes, accelerometers, velocity sensors, displacement sensors, pressure sensors, hydrophones, speed sensors, laser vibrometers, or comparable sensors or systems.When actively controlling the SPCS system, preferably one of the L reference sensors is actively used in the control core. However, control using multiple reference sensors is also possible in principle.

[0061] H ∈ ℂ M×L is the transfer function between the acoustic source S, composed of up to L sub-sources or detected via L reference sensors, and the measured acoustic partial powers P. S,m or P S,m,weight . Is the total acoustic power P used in the SPCS control core? S or P S,weight By working, the dimension of H is reduced to H ∈ ℂ 1×L In the practical implementation of SPCS, H cannot be directly measured, but only based on reference sensors. Thus, H represents the transfer function between L reference sensors and M intensity probes.

[0062] The actual control within the SPCS system is based on the superimposed primary acoustic power components of the source S and the secondary acoustic power of the sound intensity actuators according to Eq. 25, Eq. 26, Eq. 27 or Eq. 28. In the internal control of the SPCS system, in practical implementation, one of the error vectors e from Eqs. 29 - Eq. 32 is used, specifying a setpoint (subscript setpoint). em=Pm−Pm,soll;with e∈ℂMx1 em=Pm,weight−Pm,weight,should;with e∈ℂMx1 e=P−Psoll; with e∈ℂ1x1 e = Pweight − Pweight, target; with e ∈ ℂ1 x 1

[0063] Regardless of which of equations 29 to 32 are used for control within the SPCS system, the following general relationships result. For calculating the optimal control parameters or source strengths q optFor the sound intensity actuators, the system of equations (Eq. 33) must be solved such that the error signal e is minimized or becomes zero. P X can represent P m , P m,weight , P weight or just P. e=PX−PX,target=0

[0064] Using the transmission functions accordingly Fig. Eq. 34 follows 6 and subsequent explanations. PX* Eq. 34 represents the difference between the emitted acoustic power of the source S and the setpoint to which the SPCS system should regulate, so that the error e is minimized or becomes identically zero. e=PS,X+G⋅q−PX,set=PX*+G⋅q=0

[0065] The solution of Eq. 34 for calculating the optimal source strengths q opt The sound intensity actuators are achieved purely formally by inverting the matrix G and are shown in Eq. 35. qopt=−G−1⋅PX*

[0066] The method used to invert matrix G in Eq. 35 depends on the number of sound intensity actuators N and sound intensity probes M. The following configurations are possible and are covered by the functionality of the SPCS system. Variant 1: N > M → underdetermined system of equations that is solved after prior regularization using Thikhonov, singular value decomposition (SVD) or an equivalent method. Variant 2: N = M → a specific system of equations that can be solved directly Variant 3: N < M → overdetermined system of equations that is solved using Moore-Penrose pseudoinverse, Thikhonov regularization, singular value decomposition (SVD) or an equivalent method

[0067] In solution variant 1, the number of sound intensity actuators is greater than the number of intensity probes, resulting in an underdetermined system of equations. This can be solved by using regularization methods, preferably Tikhonov, singular value decomposition, Lasso, or another equivalent method. After Tikhonov regularization (Eq. 36) and specifying the regularization parameter ψ, q can be solved using Eq. 37. opt calculated according to Eq. 38. (GH⋅G+Ψ)⋅qopt=−GH⋅PX*; with Ψ=ψ⋅INxN GTikh−1=(GH⋅G+Ψ)−1 qopt,Thikh=−GTikh−1⋅GH⋅PX*

[0068] The calculation of q opt Alternatively, it can also be done according to Eq. 41, where first the singular value decomposition of the matrix G (Eq. 39) and then its inverse based on that. GSVD−1 calculated according to Eq. 40. G=U⋅S⋅VH GSVD−1=V⋅S+UH; with S+=pseudoinverse of S qopt,SVD=−GSVD−1⋅PX*

[0069] Another possibility is to q opt to determine iteratively using a gradient descent method. This is one possible solution variant in the real-time control kernel of the SPCS system and is preferably implemented using the Least Mean Square (LMS) or the Normalized Least Mean Square (NLMS) algorithm. In the following, only NLMS will be referred to, even though both variants are implemented in the SPCS system. Derived variants using reference sensors, such as the filtered LMS (FxLMS) or the Feedback Canceling FxLMS (FBFxLMS) algorithm, can also be implemented by the control kernel of the SPCS system. The iterative solution q opt Using Tikhonov regularization and the Normalized LMS algorithm (NLMS), it is formally determined according to the formation rule in Eq. 42. qopt(i+1)=qopt(i)+((η‖GTikh‖22)⋅((GTikh⋅qopt(i)+PX,Tikh*)H⋅GTikh)H)

[0070] In Eq. 42, i denotes the current iteration step, G Tikh the matrix G modified for the solution using Tikhonov regularization (Eq. 43) and PX, Tikh* a modified input vector (Eq. 44). GTikh=(GH⋅G+Ψ)⋅;with Ψ=ψ⋅INxN PX,Tikh*=GH⋅PX*

[0071] The step size or convergence rate of the method is controlled by the parameter η in Eq. 42 which must lie in the interval 0 < η ≤ 2.

[0072] In solution variant 2, the number of sound intensity actuators equals the number of intensity probes, resulting in a precisely determined system of equations, allowing the inverse of G to be calculated directly. For the direct solution, equation 36 simplifies to equation 45. qopt=−G−1⋅PX*

[0073] Equations 39 to 41 remain fully valid. In the iterative solution, equation 42 simplifies to equation 46. qopt(i+1)=qopt(i)+((η‖G‖22)⋅((G⋅qopt(i)+PX,Tikh*)H⋅GTikh)H)

[0074] The use of a regularization method in the active operation of the SPCS system, as described in detail in solution variant 1, is also fundamentally possible here and may be advantageous. Likewise, active control by the SPCS system can be based on the singular value decomposition described in Eqs. 39 to 41.

[0075] In solution variant 3, the number of sound intensity actuators is smaller than the number of intensity probes, resulting in an overdetermined system of equations that can be solved using the classical method of squared errors. Formally, this only requires setting the Tikhonov regularization parameter in Eq. 37 ψ = 0 to obtain the solution for q. optEquation 38 can be calculated directly. Equations 39 to 41 can also be used without restriction for the direct solution. Within the SPCS system, the iterative solution of q is preferred. opt Eq. 42 with ψ = 0. The use of a regularization method in the active operation of the SPCS system, as described in detail in solution variant 1, is also fundamentally possible and may be advantageous. The use of singular value decomposition, described in Eqs. 39 to 41, in active control by the SPCS system is also possible. 1.2 Further comments on the control procedure in the SPCS system:

[0076] In the previous presentation, the possible solutions to Eq. 33 were based solely on P. X,sollThis is illustrated. In technical implementation, this corresponds to a "feedback" control system, which, however, is only promising with certain acoustic characteristics of the source S, such as pronounced periodicity. Internal control in the SPCS system is therefore preferably carried out using the "feedforward" strategy (operating mode of the SPCS system: feedforward). The following scheme is intended for this purpose ( Fig. 7a) serve as an aid to explanation. Furthermore, it is noted that the following explanations assume that the SPCS system operates in the frequency domain, which means that any convolution operations can be represented as simple complex-valued multiplications. Without loss of generality, the following statements also apply to the time domain or to the case where the SPCS system operates in the time domain.

[0077] In the "feedforward" strategy, the control signal q for the sound intensity actuators is determined based on a convolution between a reference sensor signal s and a filter w. Since "acoustic feedback" from the actuators to the reference sensors is not yet considered in this explanatory example, s = s*, where s* is the direct signal component from the source S to the reference sensor. The acoustic intensities generated by the individual actuators are transferred to the individual intensity probes by the transfer function G. In this context, G is also referred to as the secondary path. At the individual intensity probes of the SPCS system, there is a superposition with the acoustic intensity field s* · H of the source S. The superimposed signal is called the error signal e, which, by adjusting the filter weights in w (see also FCU ( Fig. 11 - reference numeral 30)), e.g., using the LMS or NLMS algorithm, is to be minimized or made zero. This allows equations 42 and 46 to be reformulated as 42b and 46b, respectively. wopt(i+1)=wopt(i)+((η‖(G⋅s)Tikh‖22)⋅(e*H⋅(G⋅s)Tikh)H) wopt(i+1)=wopt(i)+((η‖G⋅s‖22)⋅(eH⋅(G⋅s))H) e*=GH⋅e (G⋅s)Tikh=((G⋅s)H⋅(G⋅s)+Ψ);with Ψ=ψ⋅INxN

[0078] In the case of regularization according to Tikhonov or when using the Moore-Penrose pseudoinverse with ψ = 0 (Eq. 42b), in the NLMS control loop (see also FCU ( Fig. 11 - Reference numeral 30)) the modified error signal e * (Eq. 47a) and to form the modified form of the transfer function G (Eq. 47b).

[0079] Another way to calculate the filter weights w within a feedforward is to calculate the necessary inverse of G using the singular value decomposition (SVD) according to equations 39 to 41. Following the terminology FxLMS, ​​we call the SVD-based method FxSVD. For this purpose, the NLMS block is used in Fig. 7a replaced by the SVD block ( Fig. 7b); see also FCU ( Fig. 11 - Reference 30). Possible uses of SVD in the SPCS control core - Option 1:

[0080] The first application option is more theoretical in nature and involves calculating the SVD based on the convolution between G and s. However, this has the crucial disadvantage that the SVD must be recalculated in "real time" in the control kernel for each new data block. Due to the high numerical requirements of the SVD, this is not yet feasible with currently available systems used in the control kernel of the SPCS system, such as FPGAs (Field Programmable Gate Arrays) or DSPs, or comparable systems, or such systems are the subject of current research and development. Possible uses of SVD in the SPCS control core - Option 2:

[0081] The second option is to calculate the inverse of G, which is needed for control, "offline" after system identification using the SVD. In the technical implementation of the SPCS system, the calculation of GSVD−1 according to Eq. 40 in the OCU ( Fig. 11 - reference 34) and will be moved to the SVD block before the start of active regular operation ( Fig. 7b) or the FCU ( Fig. 11 - reference numeral 30) is transferred. The convolution of the reference signal s = s* with G is omitted (G = 1) and is instead performed indirectly in the SVD block (see Fig. 7b or also FCU ( Fig. 11 - Reference numeral 30)). Using equations 40 and 48, GSVD,Mod−1 calculated. GSVD,Mod−1=GSVD−1∅s;with∅=Hadamard Division

[0082] From Eq. 48, the optimal filter weights w can then be calculated directly using Eq. 49. wopt=(GSVD,Mod−1⋅e)∅s

[0083] Optionally, it is also possible to omit the full SVD variant from the control core of the SPCS system. GSVD,Mod−1 Instead of using a method that uses all singular values, it's better to work with a variant that uses only a limited number of singular values ​​to approximate the inverse. This variant is called "Truncated SVD" or TSVD and provides the inverse. GTSVD,Mod−1. It is also possible to calculate the SVD based on the matrix G modified by Tikhonov regularization. Tikh (Eq. 43) and its inverse GTikSVD−1 to determine.

[0084] A combination of both optional variants is also possible in the SPCS system and delivers the inverse. GTikTSVD−1. If one of the two variants with Tikhonov regularization is used within the SVD framework, then the modified error signal e is also used. * (Eq. 47a) to work.

[0085] The use of SVD has the decisive advantage that the iterative solution of w optUsing NLMS and the associated iterative inversion of G is no longer necessary, and the solution can instead be calculated very quickly and efficiently directly in the real-time kernel of the SPCS system, based on simple matrix operations. The computationally intensive inversion of G has already been performed "offline".

[0086] In numerical experiments conducted with a MIMO setup of up to N = 500 sound intensity actuators and M = 10 acoustic intensity probes M, the ratio of computation times between the NLMS variant and the SVD variant was F speedup = t NLMS / t SVD , in the range between 9000 and 15000. For massive MIMO systems, with, for example, N = 500 sound intensity actuators and M = 10 acoustic intensity probes, the ratio increases significantly again and lies in the range of F speedup Approximately 50,000.

[0087] With the FxSVD concept shown here, the SPCS system can be implemented based on a MIMO control method, in which significantly more sound intensity actuators and intensity probes are used than would be possible with the FxLMS concept due to the computation times.

[0088] Independently of the present invention, the SPCS system, the FxSVD concept can be used for all applications where active control, similar to that in Fig. 7a and Fig. Figure 7b shows that it is based on an adaptive filter and that the filter weights w are calculated using an LMS-based algorithm. In particular, the FxSVD concept can be applied in the entire Active Noise Control (ANC) field wherever control based on the LMS algorithm or algorithms derived from it is currently used.

[0089] In general, the use of the FxSVD concept in ANC systems promises significant advantages, such that it makes massive MIMO control concepts technically feasible in the first place, using a large number of actuators and sensors.

[0090] Within the SPCS system, the control core has the option of operating in both NLMS and SVD modes.

[0091] The previous descriptions and explanations have not yet addressed the issue of "acoustic feedback" from the actuators to the reference sensors. Taking into account the actuators' effect on the reference sensor signal results in the FBFxLMS algorithm ( Fig. 7d).

[0092] The feedback effect of the actuators s A = s · w · Z on the reference sensor signal s = s* + s A The result is calculated from this via a feedback path before the convolution with the filter w takes place.

[0093] The neutralization of "acoustic feedback" can be achieved in the same way for the FxSVD algorithm ( Fig. 7b) can be implemented, whereby the previously made remarks apply and this variant is designated as FBFxSVD. 1.2 Configuration of the SPCS system for use in pipelines and ducts

[0094] The previous explanations of the SPCS system were based on the example of acoustic power emission into the free field or the outside environment; see also Fig. 1 to Fig. 4. However, the SPCS system can also be used within pipelines or ducts to modify and / or reduce the spectral composition of the acoustic power emitted by a source S. Within pipelines and ducts, pumps, compressors, fans, or similar systems would be the primary emitters of acoustic power. Fig. Figure 16 shows the schematic setup of the SPCS system as a single configuration, on one side of the source S, within a pipeline. This configuration is preferably used when the source S has a main direction of acoustic radiation. If the source S is a pump, fan, or compressor, for example, the main acoustic radiation direction usually coincides with the direction in which the fluid is conveyed. This is referred to as the pressure side of the source S.

[0095] The N sound intensity actuators ( Fig. 16 - reference 8) as well as the M sound intensity probes ( Fig. 16 - reference numeral 15) are arranged on the pressure side of the source S. The orientation of the main radiation direction of the individual sound intensity actuators, which are integrated into the pipe or duct wall, relative to the main radiation direction of the source S can be chosen arbitrarily and can be different for each sound intensity actuator. The distance of the N sound intensity actuators to the source S can also vary. Single-axis ( Fig. 17 - Reference numeral 15a), 2-axis ( Fig. 17 - reference 15b) or multi-axial ( Fig. 17 - Reference numeral 15c and Fig. 17 - Reference numeral 15d) Probes are used. Preferably, these are pu probes, pp probes, or any other type of sensor or sensor combination for measuring the acoustic active and reactive intensity; see notes “1. Basic structure of the SPCS system”. There are two variants for the arrangement of the sound intensity probes, which are referred to as ( Fig. 17 - Opt1) and ( Fig. 17 - Opt2). In the Opt1 variant, the intensity probes are either integrated flush with the wall directly into the pipe or duct wall or installed in close proximity to the wall. The technically simplest solution is the flush integration of 1-axis or 2-axis intensity probes according to the pp principle. If, for example, acoustic intensity probes are used according to the pp principle, the axes of the intensity probes can consist of at least two microphones, two hydrophones, or two pressure sensors spaced Δr apart. Any other combination of two sensors for the simultaneous measurement of acoustic pressure and determination of the spatial pressure gradient can also be used.

[0096] The positions of the individual intensity probes are given in the coordinates of the GCS ( Fig. 16 - Reference numeral 7) defined. The distance of the individual intensity probes to the source S can vary. If acoustic intensity fields with pronounced three-dimensionality predominate within the pipeline or duct, additional intensity probes can be integrated directly into the pipeline (cross-section) or the duct itself ( Fig. 17 - Opt2). In the presence of a background flow field, the intensity probe must be adequately shielded against the influence of the flow using suitable measures.

[0097] The allocation of surface elements C S,1 , C S,m up to C S,M (see also Fig. 17 - reference symbol 11) and the respective surface normal vectors n→O1,n→Om to n→OM The mapping of individual intensity probes is preferably based on a mesh of the cross-sectional area of ​​the pipeline or channel, with the positions of the intensity probes as support points. Any numerical meshing method can be used for this purpose.

[0098] If required by the radiation characteristics of the source S or the acoustic properties of the pipeline or duct, sound intensity probes and sound intensity actuators can be integrated on both sides of S; see Fig. 18. This would be the case, for example, with pumps, fans, or compressors if significant acoustic power emissions also occur via the intake side. Sound intensity sensors and actuators can be part of a single dual SPCS system (variant 1), as shown in Fig. 18, or can be operated via two independently operating SPCS systems (Variant 2). If there is a strong acoustic feedback between the sound intensity actuators on one side of the source S and the sound intensity probes on the other side of the source S, then Variant 1 is preferably used. If this is not the case, then Variant 2 is preferably used. 2. Operating modes of the SPCS system

[0099] Explanations of the abbreviations used in the block diagrams can be found in section 2.2.7. 2.1. System identification procedure of the SPCS system

[0100] The APCU of the SPCS system ( Fig. 8 - Reference numeral 25) first performs a system identification before manipulating the spectral composition and / or reducing the acoustic power emitted by source S. During system identification, the transfer functions contained in matrices H, Z, and G are determined. H is determined under one or more steady-state operating conditions of the sound power source S. 2.1.1 Determining the matrix G

[0101] To determine the matrix G, the sound intensity actuators ( Fig. 8 - Reference sign 8) are driven sequentially using white noise or purely harmonic signals. The drive signals ( Fig. 8 - reference 23) are generated by a signal generator SGU ( Fig. 8 - Reference numeral 22) for each sound intensity actuator is generated separately and sequentially and fed into the respective amplifier units APU ( Fig. 8 - reference numeral 24). The emission of an acoustic intensity field by the controlled actuator n results in an effect on the sub-areas C. S,m ( Fig. 4 - Reference sign 11) generates an acoustic intensity field distribution.

[0102] Through the intensity probes ( Fig. 8 - Reference numeral 15) the projected intensity components are measured on the individual probe axes; see also Fig. 5. The signals of the individual, projected intensity components ( Fig. 8 - 16), which were generated by the intensity actuator n, are within the IAPCU ( Fig. 8 - Reference 17) by the GICU ( Fig. 8 - Reference numeral 18) according to Eq. 17 to Eq. 20 on I→Am, regarding the GCS ( Fig. 1 to Fig. 5 - reference numeral 7), converted. The necessary direction vectors of the probe axes for this. n→I,1m, n→I,km until n→I,Km The intensity probes 1, 2, ..., m, M are in the OCU ( Fig. 8 - Reference numeral 34) are stored electronically and are used as a signal ( Fig. 8 - Reference 41) into the GICU ( Fig. 8 - Reference 18) of the IAPCU ( Fig. 8 - reference 17) transferred.

[0103] The environmental conditions at the time of system identification are determined by the EDU ( Fig. 8 - reference 38) measured and as signals ( Fig. 8 - reference 40) into the GICU ( Fig. 8 - reference 18) transferred, where they can be reused if necessary. The environmental conditions, which are always determined by the EDU ( Fig. 8 - Reference numeral 38) include pressure (static), temperature, and flow velocity in magnitude and direction. The determination of the flow direction by the EDU ( Fig. 8 - Reference numeral 38) is carried out by measuring the three velocity components with respect to the GCS ( Fig. 1 to Fig. 5 - reference sign 7) or in the form of two angles opposite two basis vectors of the GCS ( Fig. 1 to Fig. 5 - reference numeral 7). In the event that the fluid in which the SPCS system is used is normal ambient air, the relative humidity will continue to be measured by the EDU ( Fig. 8 - reference numeral 38). If the fluid in which the SPCS system is used is water, the salt content (salinity) is measured by the EDU ( Fig. 8 - reference 38) measured. The EDU ( Fig. 8 - Reference numeral 38) is equipped with the necessary sensors / measuring systems for measuring the defined quantities, or these can be connected there.

[0104] From the signals I→Am the individual intensity probes ( Fig. 8 - reference 19) are subsequently in the APSU ( Fig. 8 - Reference numeral 20) according to Eq. 21 to Eq. 24 the acoustic partial performance on the partial areas C S,m determined. The required areas of the sub-areas C S,m , as well as the surface normal vectors n→Om are in the OCU ( Fig. 8 - Reference numeral 34) are stored electronically and are used as a signal ( Fig. 8 - Reference 41) into the APSU ( Fig. 8 - Reference 20) of the IAPCU ( Fig. 8 - reference numeral 17) transferred. The weighting factors w m are during the system identification of matrix G (Eq. 23) by the IAPCU ( Fig. 8 - Reference 17) in the APSU ( Fig. 8 - Reference 20) automatically set to one.

[0105] The specific acoustic components are represented as separate signals ( Fig. 8 - Reference 21) into an Adaptive Filter Unit ADFU ( Fig. 8 - reference 26) transferred, which constitutes the actual regulatory core of the APCU ( Fig. 8 - reference 25) of the SPCS system. The control signal ( Fig. 8 - Reference 23) from the SGU ( Fig. 8 - Reference 22) is entered into the ADFU ( Fig. 8 - reference 26) transferred and with the filter weights of the FU ( Fig. 8 - reference 27) folded. The output signal of the frequency converter ( Fig. 8 - reference 32) is subsequently replaced by the signal ( Fig. 8 - Reference numeral 21) of the acoustic partial power on area segment C S,m subtracted and the FCU ( Fig. 8 - reference 30) as a signal ( Fig. 8 - reference 33). Within the FCU ( Fig. 8 - reference numeral 30) implements the NLMS algorithm. The control signal ( Fig. 8 - reference 23) will continue to be used with the filter weights of the SPFU ( Fig. 8 - Reference numeral 28) folded. In operating mode “System identification”, all filter weights of the SPFU are identical 1.

[0106] The output signal ( Fig. 8 - reference 29) will then also be the FCU ( Fig. 8 - reference 30). The FCU ( Fig. 8 - reference numeral 30) calculates iteratively, preferably using the NLMS algorithm, from the two supplied signals ( Fig. 8 - reference 29) and ( Fig. 8 - Reference numeral 33) new filter coefficients that of the FU ( Fig. 8 - reference 27) as a signal ( Fig. 8 - reference 31). This will continue until the ADFU ( Fig. 8 - Reference 26) defined convergence criterion is met.

[0107] The result is the transfer function G. mn in the form of the filter weights of the FU ( Fig. 8 - reference 27). These are used for the OCU ( Fig. 8 - Reference numeral 34) as a signal ( Fig. 8 - reference 35) transferred and there together with those by the EDU ( Fig. 8 - reference 38) measured and as a signal ( Fig. 8 - Reference numeral 39) transferred environmental conditions are stored electronically. The procedure is repeated successively for all n ∈ {1,2, ...,N} sound intensity actuators and the m ∈ {1,2, ...,M} acoustic partial powers on the sub-surfaces until all transfer functions contained in G are determined. Using this methodology, a database structure is created in the OCU ( Fig. 8 - Reference numeral 34) realized in which the transfer functions in G are linked to the environmental conditions.

[0108] In addition to determining the matrix G with the transfer functions G mn A second matrix will be created GmnI∈ℂ3m xn determined during the identification process. These are the transfer functions between the sound intensity actuators n and the 3 components of the acoustic intensity vector measured by the intensity probes m in the coordinates of the GCS ( Fig. 2 - Reference numeral 7). For determining GmnI The signal from the GICU ( Fig. 8 - 19) with the three intensity vector components not into an acoustic partial power on the partial area C S,m through the APSU ( Fig. 8 - reference numeral 19) are converted, but are directly used as 3 separate signals ( Fig. 8 - Reference 21) to the FCU ( Fig. 8 - Reference 30) of the AFU ( Fig. 8 - Reference numeral 26) transferred. The determination of the individual transfer functions in GmnI This is then carried out in the same way as with Matrix G. mn . 2.1.2 Determining the matrix Z

[0109] The determination of the transfer functions in matrix Z proceeds almost identically to that for G. The sound intensity actuators ( Fig. 9 - Reference symbols 8) are driven sequentially using white noise or purely harmonic signals.

[0110] The control signals ( Fig. 9 - reference 23) are generated by a signal generator SGU ( Fig. 9 - reference numeral 22) for each sound intensity actuator is generated separately and sequentially and fed into the respective amplifier units APU ( Fig. 9 - Reference 24) fed in.

[0111] The emission of an acoustic intensity field by the controlled actuator n generates an intensity field distribution that is measured by each of the L reference sensors in the RSU ( Fig. 9 - reference 36) measured and as a separate signal ( Fig. 9 - Reference 37) into the Adaptive Filter Unit ADFU ( Fig. 9 - Reference 26) of the APCU ( Fig. 9 - reference 25) of the SPCS system is transmitted. The control signal ( Fig. 9 - Reference 23) from the SGU ( Fig. 9 - Reference 22) is entered into the ADFU ( Fig. 9 - reference 26) transferred and with the filter weights of the FU ( Fig. 9 - Reference 27) folded.

[0112] The output signal of the frequency converter ( Fig. 9 - reference 32) is subsequently replaced by the signal ( Fig. 9 - reference 37) subtracted and the FCU ( Fig. 9 - reference 30) as a signal ( Fig. 9 - reference numeral 33). The control signal ( Fig. 9 - reference 23) will continue to be used with the filter weights of the SPFU ( Fig. 9 - reference 28) folded. In operating mode “System identification”, all filter weights of the SPFU ( Fig. 9 - reference 28) identical one. The output signal ( Fig. 9 - reference 29) will then also be the FCU ( Fig. 9 - reference 30). The FCU ( Fig. 9 - reference numeral 30) calculates iteratively, preferably using the NLMS algorithm, from the two supplied signals ( Fig. 9 - reference 29) and ( Fig. 9 - Reference numeral 33) new filter coefficients of the FU ( Fig. 9 - Reference 27) as a signal ( Fig. 9 - reference 31). This will continue until the ADFU ( Fig. 9 - Reference 26) the defined convergence criterion is met.

[0113] The result is the transfer function Z. ln in the form of the filter weights of the FU ( Fig. 9 - reference 27). These are used for the OCU ( Fig. 9 - Reference numeral 34) as a signal ( Fig. 9 - 35) transferred and there together with those through the EDU ( Fig. 9 - reference 38) measured and used as a signal ( Fig. 9 - Reference numeral 39) transferred environmental conditions are stored electronically. Details on the measurement of the environmental conditions are described in detail in section “2.1.1 Determination of matrix G” and “2.1.4 Further remarks on the system identification process” and apply analogously here. The procedure is repeated sequentially by controlling the n ∈ {1,2, ..., N} sound intensity actuators until all transfer functions between the actuators and the l ∈ {1,2, ...,L} reference sensors contained in Z have been determined. Using this methodology, a database structure in the OCU ( Fig. 9 - Reference numeral 34) is implemented in which the transfer functions in Z are linked to the environmental conditions. The transfer functions contained in Z are required in the operation of the SPCS system when using the FBFxLMS or FBFxSVD algorithm to account for or neutralize the acoustic feedback between actuators and reference sensors. 2.1.3 Determination of the matrix H

[0114] The determination of the transfer functions in the matrix H is carried out at one or more operating points of the source S.

[0115] The acoustic intensity field generated during the operation of the source is measured by the intensity probes ( Fig. 10 - reference numeral 15) recorded, whereby the projected intensity components are measured on the individual probe axes; see also Fig. 5.

[0116] The signals of the individual, projected intensity components ( Fig. 10 - reference 16) are within the IAPCU ( Fig. 10 - reference 17) by the GICU ( Fig. 10 - Reference numeral 18) according to Eq. 6 to Eq. 9 on I→Sm, regarding the components in the GCS (e.g. Fig. 4 - reference numeral 7), converted. The necessary direction vectors of the probe axes for this. n→I,1m, n→I,km until n→I,Km Intensity probes 1, 2,..., m, M are in the OCU ( Fig. 10 - reference 34) are stored electronically and are used as a signal ( Fig. 10 - reference 41) into the GICU ( Fig. 10 - Reference 18) of the IAPCU ( Fig. 10 - reference 17) transferred.

[0117] The environmental conditions at the time of system identification are determined by the EDU ( Fig. 10 - 38) measured and displayed as signals ( Fig. 10 - reference 40) into the GICU ( Fig. 8 - Reference numeral 18) transferred where they can be reused if necessary. Details on measuring the environmental conditions are described in detail in section “1.1 Determination of matrix G” and apply analogously here.

[0118] From the signals I→Sm the individual intensity probes ( Fig. 10 - reference 19) are subsequently in the APSU ( Fig. 10 - Reference numeral 20) according to Eq. 10 to Eq. 13 the acoustic partial powers on the partial areas C S,m determined. The required areas of the sub-areas C S,m , as well as the surface normal vectors n→Om are in the OCU ( Fig. 10 - reference 34) are stored electronically and are used as a signal ( Fig. 10 - Reference 41) into the APSU ( Fig. 10 - Reference 20) of the IAPCU ( Fig. 10 - reference 17) transferred. The weighting factors w m are during the system identification of matrix G (Eq. 23) by the IAPCU ( Fig. 10 - Reference 17) in the APSU ( Fig. 10 - Reference 20) automatically set to 1.

[0119] The specific acoustic partial performances ( Fig. 10 - reference 21) are fed into the Adaptive Filter Unit ADFU ( Fig. 10 - Reference 26) of the APCU ( Fig. 10 - reference numeral 25) of the SPCS system are transferred. Furthermore, the data on the sub-areas C are transferred. S,m certain partial services ( Fig. 10 - reference 21) into the OCU ( Fig. 10 - reference 34) transferred and stored there electronically.

[0120] The emission of the acoustic intensity field by the source S generates an intensity field distribution that is measured by each of the L reference sensors in the RSU ( Fig. 10 - Reference numeral 36) directly or indirectly detected and as a separate signal ( Fig. 10 - reference 37) into the Adaptive Filter Unit ADFU ( Fig. 10 - Reference 26) of the APCU ( Fig. 10 - reference 25) of the SPCS system is transmitted. The signal ( Fig. 10 - reference 37) is combined with the filter weights of the FU ( Fig. 10 - reference 27) then folded. The output signal of the frequency converter ( Fig. 10 - reference 32) is from the signal ( Fig. 10 - reference 21) subtracted and the FCU ( Fig. 10 - 30) as a signal ( Fig. 10 - reference numeral 33). The reference sensor signal ( Fig. 10 - reference 37) will continue to be used with the filter weights of the SPFU ( Fig. 10 - Reference numeral 28) folded. In operating mode “System identification”, all filter weights of the SPFU are identical 1.

[0121] The output signal ( Fig. 10 - reference 29) will then also be the FCU ( Fig. 10 - reference 30). The FCU ( Fig. 10 - reference numeral 30) calculates iteratively, preferably using the NLMS algorithm, from the two supplied signals ( Fig. 10 - reference 29) and ( Fig. 10 - Reference numeral 33) new filter coefficients of the FU ( Fig. 10 - reference 27) as a signal ( Fig. 10 - reference 31). This will continue until the ADFU ( Fig. 10 - Reference 26) defined convergence criterion is met.

[0122] The result is the transfer function H. ml in the form of the filter weights of the FU ( Fig. 10 - reference 27). These are used for the OCU ( Fig. 10 - reference 34) as a separate signal ( Fig. 10 - reference 35) transferred and there together with those by the EDU ( Fig. 10 - Reference numeral 38) measured environmental conditions, transferred as a signal ( Fig. 10 - reference numeral 39), stored electronically. The procedure is performed for a selected operating point of the source S for all m ∈ {1,2,...,M} acoustic partial powers P. S,m and the l ∈ {1,2, ...,L} reference sensors are repeated until all transfer functions contained in H are determined.

[0123] The procedure is then repeated for all other selected operating points of source S, and the transfer functions are also entered into the OCU ( Fig. 10 - reference 34) stored electronically. This methodology creates a database structure in the OCU ( Fig. 10 - Reference numeral 34) is realized in which the transfer functions in H are linked with specific operating point data of the source S and the environmental conditions. 2.1.4 Further remarks on the system identification process

[0124] As part of the system identification, immediately before the start of regular operation of the SPCS system, the EDU ( Fig. 8 to Fig. 12 - Reference numeral 38) also includes the environmental conditions. The transfer functions contained in G, H, and Z are valid for these environmental conditions. If there are significant changes in the environmental conditions during the operation of the SPCS system (e.g., an increase in temperature, a drop in pressure, etc.), this simultaneously leads to changes in G, H, and Z. This can negatively affect the system's performance and necessitate re-identification. Depending on the medium in which the acoustic power is emitted by the source S, re-identification due to changed environmental conditions is typically required when there is a deviation of > 2.5% of the current speed of sound c. aktuell compared to the speed of sound c Sysldent during system identification by the OCU( Fig. 8 to Fig. 12 - Reference numeral 34) is detected in the active control operation of the SPCS system.

[0125] Over a certain operating period of the SPCS system, system identifications are repeatedly performed and the determined transfer functions in G, H and Z are entered into the OCU along with the environmental conditions ( Fig. 8 to Fig. 12 - Reference 34) stored electronically.

[0126] This creates a database over a longer period in which the environmental parameters are linked to the transfer functions, which contain G, H, and Z. During active, regular operation of the SPCS system, the EDU ( Fig. 8 to Fig. 12 - Reference numeral 38) also continuously records the environmental conditions. If significant changes in the environmental conditions result in a change in the speed of sound c in the medium and a deterioration of the SPCS system performance, the OCU ( Fig. 8 to Fig. 12 - reference 34) detected, then the OCU ( Fig. 8 to Fig. 12 - Reference numeral 34) Updated transfer functions G, H, and Z are transferred to the control kernel of the SPCS system. These updated transfer functions more closely reflect the new, current environmental conditions at the time of control by the SPCS system. The updated transfer functions contained in G, H, and Z are preferably calculated using a multidimensional interpolation method (multivariate interpolation) based on a multitude of available transfer functions and environmental conditions from previous system identifications by the SPCS system. This multidimensional interpolation method can be based, for example, on n-linear, n-cubic, spline, kriging, nearest-neighbor, radial basis functions, or inverse distance weighting interpolation, or another equivalent method.The entire described procedure achieves a learning process of the SPCS system, which after a certain period of time leads to the fact that no system identifications need to be carried out, or only to a very limited extent, because the available data space from transfer functions and associated environmental conditions is sufficiently large.

[0127] Sufficiently large should mean the following. The OCU uses the current environmental conditions to determine ( Fig. 8 to Fig. 12 - Reference numeral 34) the speed of sound c aktuell The calculation revealed a deviation of more than 2.5% from the speed of sound c. Sysldent Detected during system identification.

[0128] From the OCU ( Fig. 8 to Fig. 12 - Reference numeral 34) available data set of environmental conditions and transfer functions must now, according to the chosen interpolation method and the number of data points required, be provided with a sufficient number of data sets of environmental conditions by the OCU ( Fig. 8 to Fig. 12 - reference 34) are identified, to which a speed of sound c Sysldent This includes a deviation of ≤ 2.5% from the current speed of sound c. aktuell have. Based on the identified datasets, approach functions for one of the listed interpolation methods are then parameterized. Subsequently, the updated transfer functions for the matrices G, H, and Z are calculated by the OCU ( Fig. 8 to Fig. 12 - reference numeral 34) determined by means of interpolation. 2.1.5 Processing of the data from the system identification for the active manipulation and / or reduction of the acoustic power emitted by S

[0129] The transfer functions H, Z, and G were determined in the system identification mode of the SPCS system and stored electronically in the OCU ( Fig. 8 to Fig. 12 - reference 34) stored. Before actively manipulating the spectral composition and / or reducing the acoustic power emitted by S, it must be determined which of the 4 control methods achievable in the SPCS system should be used.

[0130] The stored transfer functions, essentially G or a variant thereof, are used within the SPCS system, can be directly used for Multiple Input - Multiple Output (MIMO) control, after specifying the setpoint parameters P. m,soll or P m,weight,soll , through the ADFU real-time control kernel ( Fig. 8 toFig. 10 - Reference 26) of the SPCS system are used.

[0131] A Single Input-Multiple Output (SIMO) control system is used according to the specified setpoint parameter P. soll or P weight,soll Targeted, the individual lines of G are processed by the OCU ( Fig. 8 to Fig. 12 - reference 34) summed up, so that G SIMO as per equation 50. GSIMO=∑m=1MGmn

[0132] Regarding the SIMO regulation, the statements in section “1.2 Further remarks on the control procedure in the SPCS system” apply analogously, with the restriction that G is replaced by G SIMO to be replaced.

[0133] In a single input - single output (SISO) control system, the setpoint parameters P are specified. soll or P weight,soll , the individual rows and columns of G are processed by the OCU ( Fig. 11 to Fig. 12 - reference 34) summed up, so that G SISOThis is achieved according to Eq. 51. The simplest type of SISO control using the SPCS system is based on phase-coherent and source-intensity control of all sound intensity actuators. GSISO=∑n=1N∑m=1MGmn

[0134] In Single Input - Single Output - Multiple Expansion (SISO-ME) control, the control kernel ADFU ( Fig. 11 to Fig. 12 - Reference numeral 26) of the SPCS system, despite internal SISO control, provides individual control signals for each sound intensity actuator. The division of the frequency converter ( Fig. 11 to Fig. 12 - Reference 27) Output signal ( Fig. 11 to Fig. 12 - reference numeral 32) into the individual control signals of the individual actuators takes place in the PSU ( Fig. 11 to Fig. 12 - Reference 37).

[0135] The system identification yields the transfer functions G and G. SISOknown. Furthermore, in the context of identifying the transfer function H for specific operating points of the source S, the acoustic partial powers P were determined. S,m,X as well as P S,X in the OCU ( Fig. 11 to Fig. 12 - reference 34) saved.

[0136] Through the OCU ( Fig. 11 to Fig. 12 - Reference numeral 34) of the SPCS system, the optimal, uniform, and phase-coherent control signal of the actuators can be determined directly "offline" according to Eq. 52a. For a "feedforward" control of the SPCS system, Eq. 52b should apply, where the optimal filter weights wopt, XSISO to be determined, with which the reference sensor signal s ( Fig. 11 to Fig. 12 - Reference 37) in the FU ( Fig. 11 to Fig. 12 - reference 27) is folded.

[0137] The resulting acoustic power P AThe sound intensity actuators are given by Eq. 53. Subscript X can also represent the weighted acoustic power of source S. qopt,XSISO=−PS,XGSISO wopt,XSISO=−PS,XGSISO⋅s PA=GSISO⋅qopt,XSISO

[0138] Based on a singular value decomposition of G, its inverse can be given according to Eq. 54. G−1=V⋅S+UH; with S+=pseudoinverse of S

[0139] Is the magnitude of the vector calculated using the acoustic partial powers P? S,m,X , which were determined for a specific operating point of source S, as part of the identification of H and in the OCU ( Fig. 11 to Fig. 12 - reference numeral 34) are stored, normalized to 1 (GI.55), so a normalized, but for each sound intensity actuator individual control can be achieved. qopt,Xnorm can be calculated (Eq. 56). PS,Norm,X=PS,m,X‖PS,m,X‖ qopt,Xnorm=−G−1⋅PS,Norm,X FXSISO−ME=1∑G⋅qopt,Xnorm

[0140] The scaling factor is then applied. FXSISO−ME Calculated according to Eq. 57 for the specific operating point of source S. Eqs. 50 to 57 are performed “offline” in the OCU ( Fig. 11 to Fig. 12 - reference 34) calculated and qopt,Xnorm as well as FXSISO−ME electronically stored in this. In the active SISO-ME control mode of the SPCS system, the frequency converter ( Fig. 11 to Fig. 12 - reference 27) the output signal ( Fig. 11 to Fig. 12 - reference 32) calculated and sent to the PSU ( Fig. 11 to Fig. 12- reference 37) transferred. In the PSU ( Fig. 11 to Fig. 12 - Reference numeral 37) the division into the individual control signals of the sound intensity actuators takes place. qopt,XSISO−ME according to Eq. 58. In this context, division should be understood as the determination of an individual amplitude and phase position for each actuator. qopt,XSISO−ME=qopt,Xnorm⋅FXSISO−ME⋅PA=qopt,Xnorm⋅FXSISO−ME⋅GSISO⋅qopt,XSISO qopt,XSISO In Eq. 58, the output signal ( Fig. 11 to Fig. 12 - Reference 32) from the FU ( Fig. 11 to Fig. 12 - Reference 27). qopt,Xnorm,FXSISO−ME as well as G SISO are through the OCU ( Fig. 11 to Fig. 12 - Reference numeral 34) before the start of active control operation of the SPCS system as signals ( Fig. 11 to Fig. 12 - Reference 43) to the PSU ( Fig. 11 to Fig. 12 - reference 37) transferred. 2.2 Manipulation and / or reduction of the acoustic power emitted by source S by the SPCS system

[0141] After the SPCS system has completed system identification, the spectral composition of the acoustic power emitted by source S can be manipulated and / or reduced. In the following explanations, we assume that the SPCS system operates in "feedforward" mode with "feedback cancellation" ( Fig. 11) In principle, the SPCS system can also operate in "feedback" mode or in a hybrid mode combining "feedforward" with synthetic reference sensor signals. Feedback means that the SPCS system operates without any reference sensor signal ( Fig. 11 - Reference numeral 37) regulates the acoustic power emitted by S.

[0142] In hybrid mode ( Fig. 12) the system also works without a direct reference sensor signal ( Fig. 11 - reference 37), however, via the SGU ( Fig. 12 - Reference sign 22) synthetic reference signals ( Fig. 12 - Reference numeral 23). These are preferably purely harmonic signals with fixed amplitudes, frequencies and phase angles.

[0143] Before commissioning the SPCS system, the user determines which of the possible control methods SISO, SISO-ME, SIMO or MIMO should be used. Furthermore, it is determined which method, FBFxLMS or FBFxSVD, the FCU ( Fig. 11 - Reference numeral 30) of the ADFU control core ( Fig. 11 - Reference numeral 26) of the SPCS system is to operate; see also “1.2 Further remarks on the control procedure in the SPCS system”. Furthermore, the user must specify which of the L reference sensors is to be used for active control by the SPCS system. 2.2.1 Explanations regarding the use of the FBFxLMS control kernel

[0144] If the control method 3 (SIMO) is used in combination with the FBFxLMS algorithm, the Tikhonov regularization parameter ψ must be set according to Eq. 43. This can either be done by the user of the SPCS system or automatically by the OCU ( Fig. 11 - Reference 34).

[0145] If control method 4 (MIMO) is to be used, the Tikhonov regularization parameter ψ must also be specified if the number of sound intensity actuators N is greater than the number of intensity probes M (N > M). This can again be done by the user of the SPCS system or automatically by the OCU ( Fig. 11 - Reference 34).

[0146] For the case N < M, the SPCS system can be operated with Tikhonov regularization or only using the Moore-Penrose pseudoinverse (ψ = 0). If Tikhonov regularization is used, ψ must be specified by the user or is determined by the OCU ( Fig. 11 - reference 34) is automatically determined. When using the Moore-Penrose pseudoinverse, the OCU ( Fig. 11 - Reference sign 34) ψ = 0 automatically set.

[0147] For the case N = M, the SPCS system can operate using Tikhonov regularization, Moore-Penrose pseudoinverses, or a direct solution. If Tikhonov regularization is used, ψ must be specified by the user or determined by the OCU ( Fig. 11 - reference 34) is automatically set. When using the Moore-Penrose pseudoinverse, ψ = 0 is also automatically set by the OCU in this case ( Fig. 11 - Reference 34).

[0148] The mathematical relationships are explained in "Details on solution variant 1-3". 2.2.2 Explanations regarding the use of the FBFxSVD control core

[0149] When using an SVD-based control kernel (FBFxSVD) within the FCU ( Fig. 11 - Reference numeral 30) do not require any user input by default. Optionally, the SVD control kernel can operate in TSVD mode, as described in section "1.2 Further remarks on the control procedure in the SPCS system". Both SVD variants can operate either directly on the basis of the transfer functions of matrix G or on the basis of matrices modified by Tikhonov regularization; see also "Applications of SVD in the SPCS control kernel - Option 2".

[0150] When working in TSVD mode, the user must specify how many singular values ​​are required to form GTSVD−1 are to be used or will be used by the OCU ( Fig. 11 - Reference 34) automatically determined.

[0151] If Tikhonov regularization is used within the SVD, ψ must be specified by the user or is determined by the OCU ( Fig. 11 - Reference 34) is automatically determined and it will GTikSVD−1 or in the TSVD variant GTikTSVD−1 Definitely. The optional features can only be used with the SIMO and MIMO control methods.

[0152] The matrices are therefore available for the MIMO control procedure. GSVD,MIMO−1,GTSVD,MIMO−1,GTikSVD,MIMO−1 or GTikTSVD,MIMO−1 to choose from. For the sake of simplicity, only the following will refer to GX_SVD,MIMO−1 Spoken, where all four variants can be meant. The matrices are positioned accordingly. GSVD,SIMO−1,GTSVD,SIMO−1,GTikSVD,SIMO−1 or GTikTSVD,SIMO−1 when using the SIMO control procedure for selection.

[0153] For the sake of simplicity, only the following will refer to GX_SVD,SIMO−1 Spoken, whereby all four variants could be meant here as well. The SISO regulation procedure only states... GSVD,SISO−1 to select. 2.2.3 Further explanations regarding the configuration of the SPCS system before the start of active control

[0154] The target values ​​P X,soll according to Eq. 33, which the SPCS system is supposed to regulate, as well as the weighting factors w m for the weighting of the acoustic partial performances P m on sub-areas C S,m are in the OCU ( Fig. 11 - reference 34) are stored electronically and are used as a signal ( Fig. 11 - Reference 41) into the APSU ( Fig. 11 - Reference 20) of the IAPCU ( Fig. 11 - reference numeral 17) transferred. The required areas of sub-areas C S,m , as well as the surface normal vectors n→Om are in the OCU ( Fig. 10 - reference 34) are also stored electronically and are used as a signal ( Fig. 11 - Reference 41) into the APSU ( Fig. 11 - Reference 20) of the IAPCU ( Fig. 11 - reference numeral 17) is transferred. If no weighting factors are specified, w m = 1 automatically by the APSU ( Fig. 11 - reference numeral 20). If the SPCS system is specified with the weight factors w m If the acoustic power emitted by S is to be manipulated and / or reduced in its spectral composition, this is preferably done only when using the SISO, SIMO or MIMO control method.

[0155] The environmental conditions are controlled by the EDU during the active control of the SPCS system ( Fig. 11 - Reference numeral 38) continuously measured and as signals ( Fig. 11 - reference 40) into the GICU ( Fig. 11 - Reference numeral 18) transferred where they can be reused if necessary. Details on measuring environmental conditions are described in detail in section “2.1.4 Further remarks on the system identification process” and apply analogously here.

[0156] If real-time control is achieved using the FBFxLMS algorithm, the OCU ( Fig. 11 - Reference numeral 34) the matrix G, in the case of MIMO control, the matrix G SIMO corresponding to Eq. 50 in SIMO control or matrix G SISO In SISO control according to Eq. 51 as a signal ( Fig. 11 - Reference 41) to the SPFU ( Fig. 11 - reference 28) and FCU ( Fig. 11 - reference 30). The matrices are transferred both in the SPFU ( Fig. 11 - reference 28) as well as the FCU ( Fig. 11 - reference numeral 30) stored electronically. If a Tikhonov regularization is used, the signal ( Fig. 11 - reference 41) the specified parameter ψ, for the solution variant using Moore-Penrose pseudoinverse ψ = 0, to the FCU ( Fig. 11-30) are transferred and stored electronically there. Furthermore, the signal ( Fig. 11 - Reference numeral 41) the transfer functions of matrix Z belonging to the selected reference sensor to the FBFU ( Fig. 11 - Reference 44) transferred, which is required for the feedback cancellation.

[0157] If real-time control is achieved using the FBFxSVD algorithm, the OCU ( Fig. 11 - reference 34) the matrix GX_SVD_MIMO−1, in MIMO regulation, the matrix GX_SVD_SIMO−1 in SIMO regulation or the matrix GSVD,SISO−1 in SISO control as a signal ( Fig. 11 - 41) to the FCU ( Fig. 11 - Reference numeral 30) transferred and stored there electronically; see also “1.2 Further remarks on the control procedure in the SPCS system”.

[0158] If Tikhonov regularization is also used in connection with SVD, OCU ( Fig. 11 - reference numeral 34) additionally the matrix G or G SIMO as a signal ( Fig. 11 - Reference 41) to the FCU ( Fig. 11 - reference numeral 30) is transferred and stored electronically there in order to calculate the modified error signal according to Eq. 47a when control is active.

[0159] Furthermore, when using the FBFxSVD algorithm, the signal ( Fig. 11 - reference 41) the matrix Z to the FBFU ( Fig. 11-44), which is required for feedback cancellation. The SPFU ( Fig. 11 - reference 28) is initialized to 1 when using the FBFxSVD algorithm, since the convolution operation between the signal ( Fig. 11 - reference 46) and the SPFU ( Fig. 11 - reference 28) compared to the FBFxLMS solution variant indirectly in the FCU ( Fig. 11 - 30). The SPFU ( Fig. 11 - reference 28), which is initialized with 1, therefore has no influence on the signal ( Fig. 11 - reference 46) or the signal ( Fig. 11 - Reference numeral 46) identical to the signal ( Fig. 11 - Reference 29).

[0160] If the SPCS system is operated in the SIMO-ME control method, the OCU ( Fig. 11 - Reference numeral 34) according to Eq. 58 and the explanations in “2.1.5 Preparation of the data from the system identification for the active manipulation and / or reduction of the acoustic power emitted by S” the “offline” calculated quantities qopt,Xnorm,FXSISO−ME as well as G SISO to the PSU ( Fig. 11 - reference 37) transferred and stored electronically there. In the PSU ( Fig. 11 - Reference numeral 37) the signal is split during active control ( Fig. 11 - reference 32) into the signal ( Fig. 11 - 42) for individual control of the individual sound intensity actuators.

[0161] In the active control operation of the SPCS system, the EDU ( Fig. 11 - Reference numeral 38) a significant change in environmental conditions was measured and detected by the OCU ( Fig. 11 - Reference numeral 34) based on the signal ( Fig. If reference 39 (11) is detected, either the system identification procedure must be repeated or the OCU ( Fig. 11 - Reference numeral 34) The available dataset is large enough to calculate the transfer functions contained in matrices G, H, and Z using interpolation methods for the new environmental conditions; see also “2.1.4 Further remarks on the system identification process”. The newly identified or those identified by the OCU ( Fig. 11 - Reference numeral 34) Transfer functions calculated by interpolation in matrices G, H, and Z are transferred to the individual components of the SPCS system as described above and stored there electronically. The update of the transfer functions in matrices G, H, and Z, or of derived quantities, in the individual components of the control core occurs without interrupting the active control operation of the SPCS system. 2.2.4 Explanations regarding the active control of the SPCS system

[0162] In active control operation, the acoustic intensity fields emitted by source S and sound intensity actuators M are superimposed on the sub-areas C. S,m ( Fig. 4 - Reference sign 11). Through the intensity probes ( Fig. 11 - reference numeral 15) the projected, superimposed intensity components are measured on the individual probe axes; see also Fig. 5.

[0163] The signals of the individual, projected intensity components ( Fig. 11 - reference 16), are within the IAPCU ( Fig. 11 - Reference numeral 17) by the GICU ( Fig. 11 - Reference numeral 18) according to Eq. 6 to Eq. 9 or Eq. 17 to Eq. 20 on I→Tm, regarding the GCS ( Fig. 1 to Fig. 5 - reference numeral 7), converted. The necessary direction vectors of the probe axes for this. n→I,1m,n→I,km to n→I,Km The intensity probes 1, 2, ..., m, M are in the OCU ( Fig. 11 - reference 34) are stored electronically and are used as a signal ( Fig. 11 - reference 41) into the GICU ( Fig. 11 - Reference 18) of the IAPCU ( Fig. 11 - reference numeral 17) is transferred before the start of active control. The subscript T stands for Total and refers to the superposition of the intensity fields of source S and the M sound intensity actuators.

[0164] Equations 6 to 9 (subscript and superscript S) and 17 to 20 (subscript and superscript A) are formally identical and were introduced only to distinguish between the intensity fields of source S and the sound intensity actuators, but can be used interchangeably to convert the superimposed intensity fields to I→Tm to describe.

[0165] The environmental conditions are determined by the EDU ( Fig. 11 - reference numeral 38) measured in the active control operation of the SPCS system and as signals ( Fig. 11 - reference 40) into the GICU ( Fig. 11 - Reference 18) transferred where they can be reused if necessary.

[0166] From the signals I→Tm the individual intensity probes ( Fig. 11 - reference 19) are subsequently in the APSU ( Fig. 11 - Reference numeral 20) according to Eq. 25 to Eq. 28 the acoustic partial powers on the partial areas C S,m or determines the overall performance. The required area of ​​the sub-areas C S,m , the surface normal vectors n→Om as well as the weighting factors w m are in the APSU ( Fig. 11 - Reference 20) of the IAPCU ( Fig. 11 - Reference numeral 17) stored electronically. For the SISO, SISO-ME and SIMO control procedures, depending on the user's specification, either the unweighted, summed total acoustic power P or the weighted variant P is used. weight as a signal ( Fig. 11 - Reference 21) into the FCU ( Fig. 11 - Reference 30) of the ADFU ( Fig. 11 - reference 26), which constitutes the actual rule core of the APCU ( Fig. 11 - reference 25) represents, transferred.

[0167] If the MIMO control method is used, either the unweighted acoustic partial powers P are used, depending on the user's specifications. m or the weighted partial performances P m,weight as separate signals ( Fig. 11 - Reference 21) into the FCU ( Fig. 11 - Reference 30) of the ADFU ( Fig. 11 - reference 26) transferred.

[0168] From the RSU ( Fig. 11 - reference numeral 36) is the reference sensor signal ( Fig. 11 - Reference sign 37) to the node ( Fig. 11 - reference 46) is transferred. There, the subtraction with the output signal ( Fig. 11 - Reference 45) from the FBFU ( Fig. 11 - reference 26) instead of neutralizing the “feedback” from the sound intensity actuators. The resulting signal ( Fig. 11 - reference 47) is then transferred to the SPFU ( Fig. 11 - Reference 28).

[0169] This is done in the event that the FCU ( Fig. 11 - reference numeral 30) based on the FBFxLMS algorithm, the convolution with the transfer functions of the matrix G in MIMO control, with the transfer functions of the matrix G SIMO In SIMO control or in SISO or SISO-ME control, the convolution with the transfer function G SISO In the event that the FCU ( Fig. 11 - reference numeral 30) based on the FBFxSVD algorithm, the convolution weights in the SPFU ( Fig. 11 - reference 28) initialized with 1, so that the signals ( Fig. 11 - reference 47) and ( Fig. 11 - reference 29) are identical.

[0170] The result of the convolution operation is signaled ( Fig. 11 - Reference 29) to the FCU ( Fig. 11 - reference 30) transferred. Within the FCU ( Fig. 11 - reference numeral 30) the calculation of the filter weights which serve as a signal ( Fig. 11 - Reference 31) to the FU ( Fig. 11 - reference 27) are transferred. If the calculation of the filter weights is based on the FBFxLMS algorithm, then in the FCU ( Fig. 11 - Reference numeral 30) the equations Eq. 42b, taking into account Eq. 47a and Eq. 47b, are used in Tikhonov regularization or when using the Moore-Penrose pseudoinverse. In the direct solution using the FBFxLMS algorithm, Eq. 46b is used.

[0171] Will within the FCU ( Fig. 11 - reference 30) the FBFxSVD algorithm is used, the calculation of the filter weights for the FU ( Fig. 11 - Reference 27) based on Eq. 48 and Eq. 49 and taking into account the explanations in “2.2.2 Explanations on the use of the FBFxSVD control core”.

[0172] After the “feedback” neutralization, the signals ( Fig. 11 - reference number 47) also to the FU ( Fig. 11 - reference 27) transferred where the folding with the FCU ( Fig. 11 - reference numeral 30) calculated filter weights. At the output signal ( Fig. 11 - Reference 32) from the FU ( Fig. 11 - Reference numeral 27) in the case of a SISO or SISO-ME control, this is a single signal. In the case of a SIMO or MIMO control, a separate signal is used for each sound intensity actuator, bundled as a signal ( Fig. 11 - reference 32), provided. The signal ( Fig. 11 - reference 32) is from the FU ( Fig. 11 - Reference 27) into the PSU ( Fig. 11 - reference 37) and the FBFU ( Fig. 11 - reference 44). In the case of SISO-ME control, the calculation of the individual signals for each of the sound intensity actuators is carried out according to Eq. 58 and the explanations in “2.1.5 Processing of the data from the system identification for the active manipulation and / or reduction of the acoustic power emitted by S”. In the case of SISO control, the input signal ( Fig. 11 - Reference 32) into the PSU ( Fig. 11 - reference 37) is duplicated unchanged for each of the sound intensity actuators. In a SIMO or MIMO control system, the individual and separate control signals for each sound intensity actuator are already present, so that only a forwarding of the individual signals ( Fig. 11 - Reference 32) by PSU ( Fig. 11 - reference 37). The separate output signals from the PSU ( Fig. 11 - reference 37) are referred to as a signal or signal bundle ( Fig. 11 - Reference 32) to the amplifier unit APU ( Fig. 11 - reference numeral 24) of the associated sound intensity actuator. There, the conversion into a signal usable by the sound intensity actuator takes place, and finally the emission of the desired acoustic intensity field.

[0173] This too was from the FU ( Fig. 11 - Reference 27) to the FBFU ( Fig. 11 - Reference 44) transferred signal ( Fig. 11 - reference 32) is in the FBFU ( Fig. 11 - reference numeral 44) convolved and superimposed with the transfer functions for the selected reference sensor of matrix Z to calculate the “feedback” of the sound intensity actuators to the reference sensor signal. It should be noted again that in the case of SIMO or MIMO control, the signal ( Fig. 11 - Reference numeral 32) contains an individual and separate signal for each sound intensity actuator. The output signal ( Fig. 11 - Reference 45) of the FBFU ( Fig. 11 - reference 44) is then connected to the node ( Fig. 11 - reference numeral 46) transferred and there from the reference sensor signal ( Fig. 11 - Reference 37), which is from the RSU ( Fig. 11 - reference 36) is provided, subtracted. 2.2.5 Explanation of the active control of the SPCS system in hybrid mode

[0174] In hybrid mode ( Fig. 12) The control is carried out by the SPCS system without a direct reference sensor signal ( Fig. 11 - reference 37), however, via the SGU ( Fig. 12 - Reference sign 22) synthetic reference signals ( Fig. 12 - Reference 23) provided.

[0175] These are preferably purely harmonic signals with precisely defined amplitudes, frequencies, and phases. Since "feedback" from the sound intensity actuators to the (in this case non-existent) reference sensors cannot occur in this case, the filter weights in the FBFU ( Fig. 12 - reference 44) is initialized with 0. Thus, the signal ( Fig. 12 - Reference sign 23) before the junction ( Fig. 12 - Reference numeral 46) identical to the signal ( Fig. 12 - Reference 47) after this. Further changes result for the hybrid mode compared to the true "feedforward" regulation according to Fig. 12 and the explanations thereto. 2.2.6 Explanation of the active control of the SPCS system in feedback mode

[0176] The SPCS system can also be used for feedback control ( Fig. 13) can be configured. The control is based solely on the error signals ( Fig. 13 - reference 21) and the transfer functions from the matrices G, G SIMO or e SISO which in the FCU ( Fig. 13 - reference numeral 30) are stored electronically. The output signal ( Fig. 13 - 31) from the FCU ( Fig. 13 - reference numeral 30) already corresponds to the input signal ( Fig. 13 - Reference 32) into the PSU ( Fig. 13 - reference 37) and is carried out by the FU ( Fig. 13 - reference 27) only forwarded. The FCU ( Fig. 13 - reference numeral 30) thus directly calculates the control signals for the sound intensity actuators. The basic signal processing procedure remains the same. Fig. 12 and the explanations thereto. 2.2.6.1 Explanation of the signals (Fig.11 to Fig.13 - reference numeral 48) and (Fig.11 to Fig.13 - reference numeral 49)

[0177] As previously described, within the IAPCU ( Fig. 11 to Fig. 13 - Reference numeral 17) by the GICU ( Fig. 11 to Fig. 13 - reference numeral 18) according to Eq. 6 to Eq. 9 or Eq. 17 to Eq. 20 the signals of the individual, projected intensity components ( Fig. 11 to Fig. 13 - Reference numeral 16) on I→Tm, regarding the GCS ( Fig. 1 to Fig. 5 - reference numeral 7), converted. These are used as separate signals ( Fig. 11 to Fig. 13 - Reference 48) to the OCU ( Fig. 11 to Fig. 13 - reference 34). There, the OCU ( Fig. 11 to Fig. 13 - reference numeral 34) based on the transfer function G and the known control signals of the sound intensity actuators, which serve as a signal ( Fig. 11 to Fig. 13 - reference 49) are transferred to the OCU, the vectors I→Sm calculated.

[0178] These are the intensity vectors measured by the M intensity probes solely due to the emission of acoustic power by the sources S. These vectors are now processed by the OCU ( Fig. 11 to Fig. 13 - Reference symbol 34) is used to locate the position or changes in position of the source S in space.

[0179] To explain the procedure within the OCU ( Fig. 11 to Fig. 13 - Reference 34) will Fig. 14 and Fig. 15 used. In Fig. Figure 14 shows the hydroacoustic intensity vectors from a measurement in front of a ship's propeller in two views. It can be observed that the intensity vectors point away from the acoustic source. If the intensity vectors are traced back to their "origin" (backtracking), it can be seen that they converge at the center of the propeller or the acoustic source S. Mathematically, the problem is solved by the OCU ( Fig. 11 to Fig. 13 - reference numeral 34) solved such that, based on two measured intensity vectors, e.g. I→Sm=1 and I→Sm=2 two straight lines g1 and g2 ( Fig. 15) are defined in parametric form. In general, the lines g1 and g2 are skew due to errors in intensity measurement. The OCU then defines the values ​​for lines g1 and g2 ( Fig. 11 to Fig. 13 - Reference sign 34) iteratively the point coordinates P 12,min regarding the GCS ( Fig. 1 to Fig. 5 - Reference numeral 7) determines for which the distance between g1 and g2 becomes minimal; see Fig. 15. This procedure is repeated for all possible combinations of two measured intensity vectors. I→Sm repeated. In the graphical representation of all found points of minimum distance between 2 selected intensity vectors and the lines derived from them, the following results: Fig. Figure 14 shows a light gray dot distribution. The position of the source S in space with respect to the GCS ( Fig. 1 to Fig. 5 - reference symbol 7) is calculated by averaging the coordinates of all found points of minimum distance. In Fig. 14 is the red dot, which is located in the center of the propeller.

[0180] This procedure is performed within the OCU ( Fig. 11 to Fig. 13 - Reference numeral 34) continuously during active control, but with a different clock rate than the active “real-time” control core ADFU ( Fig. 11 to Fig. 13 - reference 26). If changes are detected in the determined position of source S, the OCU ( Fig. 11 to Fig.13 - Reference numeral 34) Updated transfer functions for matrices G, H, and Z are calculated. The calculation of these updated transfer functions can be based on analytical acoustic models, which, for example, use combinations of acoustic monopole, dipole, quadrupole, or multipole sources to describe the acoustic emission of source S with sufficient accuracy. Alternatively, numerical models can be used to solve the inhomogeneous acoustic wave equation. The boundary element method (BEM), the finite element method (FEM), the finite difference method (FDM), or any other suitable method can be used as a solution method for the inhomogeneous acoustic wave equation. The update of the transfer functions in matrices G, H, and Z, or of derived quantities in the individual components of the control kernel, is performed without interrupting the active control operation of the SPCS system. Reference sign SPCS Sound Power Control System APCU Acoustic Power Control Unit APCU Acoustic Power Control Unit IAPCU Intensity and Power Calulation Unit GICU Global Intensity Caluclulation Unit APSU Acoustic Power Summation Unit SGU Signal Generation Unit OCU Offline Calculation Unit RSU Reference Sensor Unit SPFU Secondary Path Filter Unit FBFU Feedback Filter Unit FCU Filter Calculation Unit FU Filter Unit ADFU Adaptive Filter Unit APU Actuator Power Unit PSU Phase Shift Unit EDU Environment Data Unit GCS Globales Koordinatensystem

Claims

[1] Methods for manipulating the spectral composition and / or reducing the acoustic power P emitted by a source S S by means of a system for manipulating and / or reducing the spectral composition of a first acoustic power P emitted by an acoustic source S S , showing the following procedural steps: a. Defining an envelope area C S , which is a virtual, physically non-existent, area for accounting for the first acoustic power P emitted by the source S S , where the enclosing surface C S the source S completely encloses, b. Arrangement of M intensity probes I 1 , I 2 , ..., I m , I M on surface C S , where each of the M intensity probes I 1 , I 2 , ..., I m , I M a sub-area segment C S,1 , C S,2 , ···,C S,m , CS,m the envelope area C S is assigned c. Measuring an incident first intensity vector I→Sm (with IS,1m, IS,km to IS,Km Axis directions) using the M intensity probes and determination of its components of I→Sm (IS,Xm,IS,Ym and IS,Zm) with respect to a reference coordinate system and measuring an incident second intensity vector I→Am (with I1m,Ikm until IKm axis directions) using the M intensity probes and determining its components of I→Am (IA,Xm,IA,Ym and IA,Zm) with regard to a reference coordinate system, d. Calculating the first acoustic power P S , by summing individual first acoustic partial powers P S,m , which extend over the sub-area segments C S,m are emitted, and by means of PS,m=∫cS,mI→Sm⋅n→Om⋅dA be calculated, and calculate a second acoustic power P A of N sound intensity actuators A1, A2, ..., A n , A N "by summing individual second acoustic partial powers P" A,m , which extend over the sub-area segments C S,m are emitted, and by means of PA,m=∫cS,mI→Am⋅n→Om⋅dA to be calculated, whereby n→Om surface normal vectors. e. Active control of the system by means of a control system, such that a total emitted acoustic power P, formed from the first acoustic power P S the source S and the second acoustic power P A The N sound intensity actuators are manipulated or minimized according to: P=∑m=1MPm, where Pm=∫CS,m(I→Sm+I→Am)⋅n→Om⋅dA=∫CS,mI→Tm⋅n→Om⋅dA=PS,m+PA,m where control parameters or source strengths for the N sound intensity actuators A1,A2, ...,A n ,A N based on P, P m or weighted sizes of P or P m These control parameters or source strengths are determined and sent to the N sound intensity actuators A1, A2, ..., A n ,A N be transmitted to manipulate the emitted acoustic power using these control parameters. [2] Method according to claim 1, characterized by , that each surface segment C S,1 , C S,2 , ···,C S,m , C S,m a surface normal vector n→O1,n→O2,⋯,n→Om,n→OM is assigned, whereby it is true that n→O1,n→O2,⋯,n→Om,n→OM constant over the respective, assigned area segment C S,1 , C S,2 , ···,C S,m , C S,m is. [3] Method according to claim 1 or 2, characterized by, that the enveloping surface C S for the division into area sub-segments C S,1 , C S,2 , ...,C S,m , C S,M discretized under the assumption that acoustic state variables, in particular sound pressure, particle velocity, density and / or temperature, are to a first approximation constant over all surface sub-segments C S,m are. [4] System for manipulating and / or reducing the spectral composition of a first acoustic power P emitted by an acoustic source S S for carrying out the method according to claim 1, wherein the first acoustic power P S a first acoustic intensity field I S,i trains, exhibiting system N sound intensity actuators A1, A2,..., A n , A N , where each sound intensity actuator A1, A2,..., A n , A N each with a distance R S,1 , R S,2 , ..., R S,n , RS,N and a radiation direction around the source S, but within a surface C S , are arranged, where each of the N sound intensity actuators A1, A2, ..., A n , A N is designed to create a second acoustic intensity field defined in amplitude, frequency and phase I→A,1,I→A,n to I→A,N with a second acoustic power P A to create M sound intensity probes I 1 , I 2 , ..., I m , I M , which are arranged on the surface of Cs, where the M sound intensity probes I 1 , I 2 , ..., I m , I M in each of the K axis directions, the component of an incident intensity vector projected onto the respective axis direction I→Sm measure and at least one device for electronic signal processing and active control, wherein the at least one device for electronic signal processing and active control is configured to ensure that a total emitted acoustic power P, formed from the first acoustic power P S the source S and the second power P A the N sound intensity actuators are manipulated or minimized. [5] System according to claim 4, characterized by , that the acoustic source S is composed of L individual acoustic sources. [6] System according to claim 4, characterized by , that the emitted first acoustic power P S is formed from a first active acoustic power P S_active or a reactive performance P S_reactive or a sum of both according to PS=PS_active+j⋅PS_reactive (with j 2 = -1 imaginary unit). [7] System according to claim 4, characterized by, that the emitted first acoustic power P S the integral of the intensity I of the source S S,i (C s ) via the virtually conceived surface C S is. [8] System according to claim 4, characterized by , that the N sound intensity actuators A1, A2, ..., A n , A N within the area defined by C S are distributed over a limited area using a probabilistic method, preferably using a Poisson-Disc Sampling method. [9] System according to claim 4, characterized by , that a spatial orientation of the N actuators A1, A2, ..., A n , A N can be determined by means of a predetermined probability distribution, preferably a Poisson distribution or a Gaussian distribution. [10] System according to claim 4, characterized by , that the N sound intensity actuators A1, A2, ..., A n , A NControllable systems are those with which an acoustic intensity field defined in amplitude, frequency and phase can be created. I→A,1,I→A,2,⋯,I→A,n,I→A,N is generated individually by each sound intensity actuator. [11] System according to claim 4, characterized by that the adjustable systems are loudspeakers, underwater loudspeakers and / or structure-borne sound transducers. [12] System according to claim 4, characterized by , that each sound intensity probe I 1 , I 2 , ···, I m , I M on each surface segment C S,1 , C S,2 , ···,C S,m , C S,m is arranged. [13] System according to claim 4, characterized by , that each sound intensity probe I 1 , I 2 , ···, I m , I M is designed as uniaxial (one-dimensional), biaxial (two-dimensional), triaxial (three-dimensional) or multiaxial (multi-dimensional). [14] System according to claim 4, characterized by , that the M sound intensity probes are sensors or sensor combinations for measuring an acoustic active and reactive intensity, preferably the M sound intensity probes are pu probes and / or pp probes. [15] System according to claim 4 further comprising reference sensors, wherein the reference sensors correspond to the number of L individual sources. [16] System according to claim 15, characterized by , that the reference sensors are set up to measure quantities which are directly related to the acoustic radiation of the source S. [17] System according to claim 16, characterized by , that the L reference sensors are intensity probes, microphones, accelerometers, velocity sensors, displacement sensors, pressure sensors, hydrophones, speed sensors and / or laser vibrometers. [18] Control method of a system according to claim 4 and / or of a system in a method according to claim 1 wherein control parameters for the N sound intensity actuators A1, A2,..., A n , A N The following procedural steps will be used to determine this: a. A system identification is performed, whereby the following transfer functions (in the frequency domain) are determined: the transfer function G between the N sound intensity actuators A1, A2,..., A n , A N and the partial powers P measured by the sound intensity probes A,m , where a G-matrix is ​​determined to determine the transfer functions, b. Calculation of the control parameters q of the N sound intensity actuators A1, A2,..., A n , A N by solving a system of equations according to e=PS,X+G⋅q−PX,set=PX*+G⋅q=0 using the transfer function G, such that an error signal e is minimized or becomes zero, where P S,X P S,m , P S,m,weight , P S,weight or P is and P X,soll a target value for P S,m , P S,m,weight , P S,weight or P. [19] Control procedure according to claim 18, characterized by , that furthermore the transfer function Z between the N sound intensity actuators and the L acoustic sources or L reference sensors and / or the transfer function H between the first acoustic source S, composed of up to L sub-sources or detected via L reference sensors, and the measured acoustic partial powers P S,m or P S,m,weight , where a Z- and / or H-matrix is ​​determined for each of the transfer functions Z and H. [20] Control procedure according to claim 19, characterized bythat the control is carried out using a Single Input - Single Output (SISO) method, or a Single Output - Multiple Expansion (SISO-ME) method, or a Single Input - Multiple Output (SIMO) method, or a Multiple Input - Multiple Output (MIMO) method. [21] Control method according to one of claims 18-20, characterized by that the regulatory procedure is being carried out a. without reference sensors (feedback operating mode) or b. with reference sensors (feedforward operating mode) or c. without reference sensors but with a synthetic reference signal generated by the control system (hybrid operating mode). [22] Control method according to one of claims 18-21, characterized by , that the calculation of the control parameters q for the actuators is based on the error signals e by a. an FBFxLMS algorithm using a Tikhonov regularization or Moore Penrose pseudoinverse or b. a depicted FBFxSVD algorithm using a singular value decomposition (SVD), truncated SVD (TSVD) and / or in combination with a regularization according to Thikonov. [23] Regulatory procedure according to claim 20, characterized by that the methods are applicable to any linear problems of the form A__⋅x_=b_ are transferable, for which a real-time capable solution for x is sought. [24] Control procedure according to claim 23, characterized by , that it is transferable to classic ANC problems for minimizing sound pressure using the LMS method as well as in SIMO and MIMO systems.

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