Minimizing unwanted responses in haptic systems
Disclosed are methods to manipulate a given parametrized haptic curve in order to yield a smooth phase function for each acoustic transducer which minimizes unwanted parametric audio. Further, the impulse response of a haptic system describes the behavior of the system over time and can be convolved with a given input to simulate a response to that input. To produce a specific response, a deconvolution with the impulse response is necessary to generate an input.
1. A method comprising:
generating a drive amplitude and phase of a resonant system to substantially realize a desired drive amplitudes and phases, wherein the resonant system comprises an impulse response of the resonant system, a history of drive phases and amplitudes, and a desired output;
reducing the impulse response to Fourier components at the resonant system's resonant frequency to create a reduced-form impulse response;
using the reduced-form impulse response and the history of drive phases and amplitudes to create a predicted current state of the resonant system;
using the reduced-form impulse response, the predicted current state of the resonant system, and the desired output to generate a final drive amplitude and a final phase.
2. The method as in claim 1 , wherein the impulse response used changes in response to at least one of historical drive data, predicted drive data, temperature, age, altitude, external sensors and simulations.
3. The method as in claim 1 , wherein the reduced-form impulse response, the predicted current state of the resonant system, and the desired output to generate the final drive amplitude and the final phase using an equation:
D 0 =( V 0 −( D·h ))/ h 0 ·;
where V 0 represents desired output, D 0 represents calculated final amplitude and phase, h 0 represents a first-period impulse response Fourier component, Dis a vector containing time-shifted historical driving values, and his a second vector containing time-shifted impulse response Fourier components.
4. The method as in claim 1 , wherein the desired drive amplitudes and phases are filtered to reduce audio generation.
5. The method as in claim 1 , wherein the final drive amplitude and the final drive phase is realized as a digital signal.
6. The method as in claim 1 , wherein the final drive amplitude and the final drive phase is realized as an analog signal.
7. The method as in claim 1 , wherein the impulse response is computed recursively, subject to a limit.
8. The method as in claim 1 , wherein the resonant system measures the impulse response occasionally to adjust stored values.
9. The method as in claim 1 , wherein the resonant system comprises multiple sub-elements, each which are individually addressed.
10. The method as in claim 9 , wherein the resonant system comprises:
an array composed of impulse responses of coupled sub-elements;
the history of drive phases and amplitudes is a list of historical drive signals to each of the coupled sub-elements;
the desired output is a list of desired outputs for each of the coupled sub-elements; and
the desired drive amplitude and phase is a list of outputs for each of the sub-elements.
11. The method as in claim 10 , wherein an array of the reduced-form impulse response Fourier components, a first list of the predicted current states of each sub-element, and a second list of the desired output of each sub-element generate a third list of the calculated drive amplitudes and phases using an equation:
D
0
=
h
0
-
1
(
V
-
(
h
1
h
2
⋯
h
n
)
(
D
1
D
2
⋮
D
n
)
)
;
where
V
=
(
V
1
⋮
V
m
)
,
h
n
=
(
h
11
n
h
21
n
⋯
h
m
1
n
h
21
n
h
22
n
⋱
⋮
⋮
⋱
⋱
⋮
h
m
1
n
⋯
⋯
h
mmn
)
,
D
n
=
(
D
1
n
⋮
D
m
n
)
,
n represents a given period delay offset, numbered indexes in
h
n
=
(
h
11
n
h
21
n
⋯
h
m
1
n
h
21
n
h
22
n
⋱
⋮
⋮
⋱
⋱
⋮
h
m
1
n
⋯
⋯
h
mmn
)
are impulse response Fourier components on a sub-element specified by the second number when a sub-element represented by the first number is driven and h 0 −1 is an inverse of the first-cycle matrix of the impulse response array; D n is the time-shifted historical drive values for each of m sub-elements; and
wherein an output of the equation (D 0 ) is a list of driving coefficients for m sub-elements given a desired m outputs in V.