ARRANGEMENT AND METHOD FOR IDENTIFYING AND COMPENSATING NONLINEAR VIBRATION IN AN ELECTRO-MECHANICAL TRANSDUCER

• US 20150296299A1
• Filed: 04/10/2015
• Published: 10/15/2015
• Est. Priority Date: 04/11/2014
• Status: Active Grant

• Current Assignee: Klippel, Wolfgang
• Original Assignee: Klippel, Wolfgang
• Inventors: Klippel, Wolfgang
• Granted Patent: US 9,615,174 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04R 3/04 for correcting frequency response
• CPC Class Codes: H04R 3/08 of electromagnetic transducers

Abstract

The invention relates to an arrangement and a method for converting an input signal v into an output signal p(r_a) by using an electro-mechanical transducer and for reducing nonlinear total distortion p_d in said output signal p(r_a), whereas the nonlinear total distortion p_d contains multi-modal distortion u_d which are generated by nonlinear partial vibration of mechanical transducer components. An identification system generates distributed parameters P_d of a nonlinear wave model (N_d) and lumped parameters P_l of a network model (N_l) based on electrical, mechanical or acoustical state variables of transducer measured by a sensor. The nonlinear wave model distinguishes between activation modes and transfer modes, whereas the activation modes affect the transfer modes, which transfer the input signal u into the output signal p. A control system synthesizes based on the physical modeling and identified parameters P_d and P_l nonlinear distortion signals v_d and v_l which are supplied with the input signal v to the transducer and compensate for the distortion signals u_l and u_d generated by the transducer nonlinearities.

Claims

1. Arrangement for converting an input signal v into an output signal p(r_a) by using an electro-mechanical transducer and for reducing nonlinear total distortion p_d in said output signal p(r_a), whereas the nonlinear total distortion p_d contains multi-modal distortions u_d which are generated by nonlinear partial vibration of mechanical transducer components, the arrangement comprising:

a sensor which is configured and arranged such to measure a mechanical or an acoustical state variable (p(r_s)) of said transducer and to generate a measurement signal p based on said measured state variable (p(r_s));

a first parameter detector (D₁;

D′

₁) which is configured and arranged such to generate based on said measurement signal p distributed parameters P_d, whereas

the distributed parameters P_d contain modal information H_e,m(s) of at least one activation mode, which activates the nonlinear partial vibration of the mechanical component;

the distributed parameters P_d contain multi-modal information H_s,m,n(s), which describe the nonlinear influence of the activation mode on transfer modes, whereas the transfer modes generate the output signal p(r_a);

a nonlinear wave model, which is configured and arranged such to generate based on said input signal v and said distributed parameters P_d multi-modal distortion u_d, whereas the nonlinear wave model comprises

an activation filter (H_e,m) which is configured and arranged such to generate based on the modal information H_e,m(s) a modal activation signal q_m, which describes the vibration state of said activation mode;

a transfer filter (H_s,m,n) which is configured and arranged such to generate based on the multi-modal information H_s,m,n(s) a multi-modal signal w_m,n, which describes the nonlinear relationship between the modal activation signal q_m and the multi-modal distortion u_d; and

a nonlinear connection element which is configured and arranged such to combine the modal activation signal q_m and multi-modal signal w_m,n and to generate a distortion contribution u_m,n for said multi-modal distortion u_d.

3. Arrangement according to claim 1, whereas

said activation filter (H_e,m) comprises a linear transfer behavior with a low-pass characteristic, whereas the low-pass characteristic is determined by said modal information H_e,m(s);

the transfer filter (H_s,m,n) comprises linear transfer behavior with a high-pass characteristic, whereas the high-pass characteristic is determined by said multi-modal information H_s,m,n(s); and

said nonlinear connection element comprises

a homogenous nonlinear power system, which is configured and arranged such to set said modal activation signal q_m to the power with the exponent n−

1 and to generate a powered signal B_m,n=q_m^n-1;

a multiplicator (11), which is configured and arranged such to generate a nonlinear source signal z_m,n based on a multiplication of the powered signal B_m,n with said multi-modal signal w_m,n; and

a linear post filter (H_p,m,n), which is configured and arranged such to transfer the nonlinear source signal z_m,n into a distortion contribution u_m,n, whereas the distributed parameters P_d determine the transfer function H_p,m,n(s) of the linear post filter (H_p,m,n).

4. Arrangement according to claim 1, further comprising:

at least one adding device, which is configured and arranged such to generate a total signal u_t by combining said excitation signal u with said multi-modal distortion u_d;

a second parameter detector (D₃, D′

₃), which is configured and arranged such to generate based on said measurement signal p linear parameters P_tot, whereas the linear parameters P_tot describe the relationship between said total signal u_t and said measurement signal p; and

a total transfer element which is configured and arranged such to generate based on said linear parameters P_tot and said total signal u_t an estimate p′

of said measurement signal p;

a second subtraction element which is configured and arranged such to generate an error signal e such that the error signal e describes the deviation between said measurement signal p and said estimate p′

;

whereas said first parameter detector (D₁, D′

₁) is configured to minimize said error signal e and to generate based on said linear parameters P_tot the distributed parameters P_d.

5. Arrangement according to of claim 1, further comprising:

a linear transfer element, which is configured and arranged such to generate based on said multi-modal distortion u_d and said linear parameters P_tot the total distortion p_d in said measurement signal p; and

a third subtraction element, which is configured and arranged such to generate based on the difference between the measurement signal p and the total distortion p_d a linearized measurement signal p_out, whereas the linearized measurement signal p_out contains a linear output signal p_lin of said transducers and an ambient signal p_s generated by an external source.

6. Arrangement according to claim 1, further comprising at least one of the following elements:

an electric sensor, which is configured and arranged such to measure an electric state variable of said transducer to generate an electric measurement signal i, whereas said electric measurement signal i is different form said electrical excitation signal u supplied to the transducer;

a third parameter detector (D₂), which is configured and arranged such to generate based on electrical measurement signal i and said electrical excitation signal u lumped parameters P_l, whereas said lumped parameters P_l describe the fundamental vibration mode of said transducer with the lowest natural frequency f₀ and determine the properties of said modal activation filter (H_e,0) of an order m=0;

a nonlinear network model (N_l), which is configured and arranged such to generate based on said excitation signal u and said lumped parameters P_l a unimodal distortion signal u_l, whereas the unimodal distortion signal u_l represents the signal distortion generated by the fundamental vibration mode of the order m=0;

an adder, which is configured and arranged such to generate based on the excitation signal u and said unimodal distortion signal u_l a distorted excitation signal u_c; and

a nonlinear wave model (N_d), which is configured and arranged such to generate based on said distorted excitation signal u_c and said distributed parameters P_d said multi-modal distortion u_d.

7. Arrangement according to claim 1, further comprising

a unimodal synthesis element, which is configured and arranged such to generate based on said network model (N_l) and said lumped parameters P_l a unimodal compensation signal v_l, whereas the unimodal compensation signal v_l represents a unimodal distortion signal u_l generated by said transducers contributing to said nonlinear total distortion p_d in the output signal p(r_a);

and

a fourth subtraction element, which is configured and arranged such to generate based on a difference between the control signal v_c and said unimodal compensation signal v_l the excitation signal u of said transducer.

2. Arrangement for converting an input signal v into an output signal p(r_a) by using an electro-mechanical transducer and for reducing nonlinear total distortion p_d in said output signal p(r_a), whereas the nonlinear total distortion p_d contains multi-modal distortions u_d which are generated by nonlinear partial vibration of mechanical transducer components, the arrangement comprising:

a multi-modal synthesizing element which is configured and arranged such to generate based on the input signal v a multi-modal compensation signal v_d by using a nonlinear wave model (N_d) and distributed parameters P_d, whereas

the multi-modal compensation signal v_d describes the multi-modal distortion u_d;

said distributed parameters P_d comprise modal information H_e,m(s) of at least one activation mode, which activates the nonlinear partial vibration of the mechanical component;

die distributed parameters P_d comprise multi-modal information H_s,m,n(s) which describe the nonlinear influence of the activation mode on transfer modes, whereas the transfer modes generate the output signal p(r_a);

the wave model comprises at least one activation filter (H_e,m), which is configured and arranged such to generate based on the modal information H_e,m(S) a modal activation signal q_m, which describes the vibration state of said activation mode;

the wave model comprises at least one transfer filter (H_s,m,n), which is configured and arranged such to generate based on the multi-modal information H_s,m,n(s) a multi-modal signal w_m,n, which describes the nonlinear relationship between the modal activation signal q_m and the multi-modal distortion u_d;

the wave model comprises at least one nonlinear connection element which is configured and arranged such to combine the modal activation signal q_m and multi-modal signal w_m,n and to generate a distortion contribution u_m,n for the multi-modal compensation signal v_d; and

a first subtraction element which is configured and arranged such to generate a control signal v_c based on the difference of said input signal v and said multi-modal compensation signal v_d and to supply the generated control signal v_c to the transducer.

8. Method for converting an input signal v into an output signal p(r_a) by using an electro-mechanical transducer and for reducing nonlinear total distortion p_d in said output signal p(r_a), whereas the nonlinear total distortion p_d contains multi-modal distortion u_d which are generated by nonlinear partial vibration of mechanical transducer components, the method comprising:

generating an electrical excitation signal u based on the input signal v;

exciting said transducers with said electrical excitation signal u;

measuring at least one mechanical or acoustical state variable (p(r_s)) of said transducer;

generating a measurement signal p, which describes said measured state variable;

assigning initial values to distributed parameters P_d of a nonlinear wave model (N_d), whereas the distributed parameters P_d comprise

modal information H_e,m(s), which represents at least one activation mode, whereas the activation mode activates the nonlinear partial vibration of the mechanical components; and

multi-modal information H_s,m,n(s) which represents the nonlinear influence of the activation mode on transfer modes, whereas the transfer modes generate output signal p(r_a);

generating a modal activation signal q_m based on said input signal v and said modal information H_e,m(s), whereas the modal activation signal q_m describes the vibration state of an activation mode;

generating a multi-modal signal w_m,n based on said input signal v and multi-modal information H_s,m,n(s), whereas the multi-modal signal w_m,n describes the nonlinear relationship between said modal activation signal q_m and said multi-modal distortion u_d;

generating a distortion contribution u_m,n based on said modal activation signal q_m and said multi-modal signal w_m,n, whereas said distortion contribution u_m,n describes components of said multi-modal distortion u_d;

generating updated values of said distributed parameters P_d based on said measurement signal p and distortion contribution u_m,n.

10. Method according to claim 8, further comprising at least one of the following steps:

generating a powered signal B_m,n by setting said modal activation signal q_m to the power with the exponent n−

1;

generating a nonlinear source signal z_m,n by multiplying said powered signal B_m,n with said multi-modal signal w_m,n; and

generating said distortion contribution u_m,n of modal order m and nonlinear order n based on linear filtering of said source signal z_m,n, whereas the linear filtering has a transfer function H_p,m,n(S) which is determined by the distributed parameters P_d.

11. Method according to claim 8, further comprising:

generating a total signal u_t based on said excitation signal u and said multi-modal distortion signal u_d;

generating linear parameters P_tot based on said excitation signal u and said measurement signal p, whereas the linear parameters P_tot describe a linear relationship between said total signal u_t and said measurement signal p;

generating an estimated signal p′

based on the total signal u_t and said linear parameters P_tot, whereas the estimated signal p′

describes the measurement signal p;

generating an error signal e which describes the deviation between said measurement signal p and said estimated signal p′

; and

generating said distributed parameters P_d by minimizing said error signal e based on said linear parameters P_tot.

12. Method according to claim 8, further comprising:

generating a linearized measurement signal p_out based on said measurement signal p and said excitation signal u by using said distributed parameters P_d and said linear parameters P_tot, whereas the linearized measurement signal p_out contains a linear output signal p_m of said transducer and an ambient signal p_s generated by an external source.

13. Method according to claim 8, further comprising:

generating a diagnostic information I based on said distributed parameters P_d, whereas the diagnostic information I reveals the physical causes of the nonlinear total distortion p_d in the output signal p(r_a) and is used for improving the design and manufacturing process of said transducer.

14. Method according to claim 8, further comprising at least one of the following steps:

generating an electrical measurement signal i by measuring an electrical state variable of said transducer, whereas said electric measurement signal i is different form said electrical excitation signal u supplied to the input of said transducer;

generating lumped parameters P_l of a network model (N_l) based on said electrical measurement signal i and said electrical excitation signal u;

generating modal information H_e,0(s) based on said lumped parameters P_l, wherein the modal information H_e,0(s) describes the frequency response of the fundamental vibration mode of the order m=0 with the lowest natural frequency f₀;

generating a unimodal distortion signal u_l based on said excitation signal u and said modal information H_e,0(s), whereas the unimodal distortion signal u_l represents the signal distortion generated by the fundamental vibration mode of order m=0;

generating a distorted excitation signal u_c based on the excitation signal u and said unimodal distortion signal u_l;

generating a modal activation signal q₀ of the order m=0 based on said excitation signal u and said modal information H_e,0(s);

generating a multi-modal signal w_0,n based on said distorted excitation signal u_c and said multi-modal information H_s,0,n(s) provided in said distributed parameters P_d; and

generating said multi-modal distortion u_d based on said modal activation signals q₀ and said multi-modal signal w_0,n.

15. Method according to claim 8, further comprising:

generating a unimodal compensation signal v_l based on control signal v_c and lumped parameters P_l of a network model (N_l); and

generating an excitation signal u based on the difference between the control signal v_c and said unimodal compensation signal v_l.

9. Method for converting an input signal v into an output signal p(r_a) by using an electro-mechanical transducer and for reducing nonlinear total distortion p_d in said output signal p(r_a), whereas the nonlinear total distortion p_d contains multi-modal distortion u_d which are generated by nonlinear partial vibration of mechanical transducer components, the method comprising:

generating distributed parameters P_d of a nonlinear wave model (N_d), whereas said distributed parameters P_d comprise

modal information H_e,m(s), which represents at least one activation mode, whereas the activation mode activates the nonlinear partial vibration of the mechanical components; and

multi-modal information H_s,m,n(s), which represents the nonlinear influence of the activation mode on transfer modes, whereas the transfer modes generate the output signal p(r_a);

generating a modal activation signal q_m based on said input signal v and said modal information H_e,m(s), whereas the modal activation signal q_m describes the vibration state of an activation mode;

generating a multi-modal signal w_m,n based on said input signal v and said multi-modal information H_s,m,n(s), whereas the multi-modal signal w_m,n describes a nonlinear relationship between said modal activation signal q_m and said multi-modal distortion u_d;

generating a distortion contribution u_m,n based on said modal activation signal q_m and said multi-modal signal w_m,n, whereas said distortion contribution u_m,n describes components of said multi-modal distortion u_d;

generating a multi-modal compensation signal v_d based on said distortion contribution u_m,n;

generating a control signal v_c=v−

v_d based on said input signal v and said multi-modal compensation signal v_d;

generating an excitation signal u based on said control signal v_c; and

supplying the excitation signal u to the electrical input of said transducers.