GB2538737A

GB2538737A - Active vibration control apparatus and method

Info

Publication number: GB2538737A
Application number: GB1508961.8A
Authority: GB
Inventors: Peng George; Whear Frank; Vinamata Xavier
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2015-05-26
Filing date: 2015-05-26
Publication date: 2016-11-30
Anticipated expiration: 2035-05-26
Also published as: WO2016189075A1; GB2538737B; GB201508961D0; EP3304542A1

Abstract

The invention relates to active vibration control apparatus 1 for a vehicle 2. The apparatus comprises a controller 7 including an electronic processor 10 having an electrical output for outputting a vibration control signal (SIG) to control operation of an actuator 8. The vibration control signal (SIG) is generated by combining a vibration-reducing signal (SIGv) that reduces one or more first vibration components, and a sound-generating signal (SIGs) that increases one or more second vibration components. The combined signal (SIG) is used to control actuation of the actuator (e.g. a shaker). The vibration-reducing signal (SIGv) could be generated using a signal from an accelerometer 9. In circumstances where some cylinders of the vehicles engine 5 are deactivated the apparatus may be used to actively modify vibrations in the vehicle to reduce a first component while increasing a second component so that the occupants do not notice changes to the functioning of the engine.

Description

ACTIVE VIBRATION CONTROL APPARATUS AND METHOD

TECHNICAL FIELD

The present disclosure relates to an active vibration control apparatus and method. More particularly, but not exclusively, the present disclosure relates to active vibration control apparatus operable to reduce a first vibration component and to increase a second vibration component. Aspects of the invention relate to an apparatus, to a method and to a vehicle.

BACKGROUND OF THE INVENTION

In the automotive industry, there are continuing requirements to reduce vehicle vibration and interior cabin noise. It is known to provide an electrodynamic actuator to generate vibrations in a body structure of a vehicle. By controlling the actuator to generate cancelling vibrations that are in antiphase with those generated by the powertrain, the sound transmitted into the vehicle cabin may be actively reduced or neutralised. Active acoustic controllers are known from FR2902479 and 0B2252657.

It is also known to generate sounds in the vehicle cabin to augment certain aspects of the sound generated by the powertrain. The sounds can, for example, be generated by the audio speakers provided in the vehicle cabin as part of the vehicle infotainment system.

It is against this background that the present invention has been conceived. It is an aim of the present invention to provide active vibration control for a vehicle.

SUMMARY OF THE INVENTION

Aspects of the present invention relate to an active vibration control apparatus and method.

According to an aspect of the present invention there is provided an active vibration control apparatus for a vehicle. The apparatus may comprise a controller comprising at least one electronic processor having an electrical output for outputting a vibration control signal to control operation of an actuator. The apparatus may comprise an electronic memory device electrically coupled to the at least one electronic processor and having instructions stored therein. The at least one electronic processor may be configured to access the memory device and execute the instructions stored therein such that it is operable to generate the vibration control signal. The vibration control signal may be generated by combining a vibration-reducing signal for controlling actuation of the actuator to reduce one or more first vibration component, and a sound-generating signal for controlling actuation of the actuator to increase one or more second vibration component.

In use, the vibration control signal may control the actuator to reduce the first vibration component and to increase the second vibration component. By decreasing the first vibration component and increasing the second vibration component, the vibrations transmitted into the vehicle cabin may be controlled actively. The active vibration control apparatus thereby provides a dual function.

The first vibration component may correspond to an unwanted vibration pattern, for example a harmonic vibration pattern. In certain embodiments, the first vibration component may be generated by a vehicle powertrain, for example an internal combustion engine disposed in the vehicle. The second vibration component may generate an audible sound within the vehicle cabin. The second vibration component may augment certain aspects of the audio signal transmitted into the vehicle cabin, for example certain audio characteristics of the vehicle powertrain.

The at least one electronic processor may be configured to generate said sound-generating signal. The sound-generating signal can, for example, be generated in dependence on an acoustic transfer function. The acoustic transfer function may comprise a look-up table defining the sound-generating signal for engine speed and/or engine load.

The at least one electronic processor may be configured to generate said vibration-reducing signal. The vibration-reducing signal may be generated in dependence on an accelerometer signal. The accelerometer signal may be generated by an accelerometer rigidly mounted to a body structure. The accelerometer signal may provide a real time measurement of the frequency and amplitude of vibrations in the body structure. In certain embodiments, more than one accelerometer may be provided for generating a plurality of accelerometer signals.

The accelerometer could, for example, comprise a piezoelectric accelerometer. The accelerometer could comprise a microphone. Other types of accelerometer, such as a MicroElectro-Mechanical System (MEMS) accelerometer, are also contemplated.

The one or more first vibration component may be in a first frequency range. The first frequency range may be from 10Hz to 100Hz; or from 10Hz to 50Hz. The one or more second vibration component may be in a second frequency range. The second frequency range may be different from the first frequency range. The second frequency range may be from 50Hz to 100Hz; or from 80Hz to 100Hz.

The at least one electronic processor may be configured to apply a transform to the accelerometer signal to generate the vibration-reducing signal. The transform may decompose the accelerometer signal from a time-based signal into a frequency-based signal. The transform may be a forward Fourier Transform.

The vibration-reducing signal may be generated in dependence on one or more operating parameter of the internal combustion engine. The vibration-reducing signal may be generated in dependence on an operating speed and/or a load of the internal combustion engine.

The sound-generating signal may be generated in dependence on one or more operating parameter of the internal combustion engine. The sound-generating signal may be generated in dependence on an operating speed and/or a load of the internal combustion engine.

The internal combustion engine may comprise a plurality of cylinders and one or more of said cylinders may be selectively deactivated. The at least one electronic processor may be configured to generate said vibration-reducing signal and/or said sound-generating signal in dependence on activation and/or deactivation of one or more of said cylinders. The sound-generating signal may be generated to augment sound generated by the internal combustion engine when one or more of said cylinders is deactivated.

According to a further aspect of the present invention there is provided an active vibration control apparatus as described herein comprising said actuator. The actuator is operable to generate vibrations in dependence on said vibration control signal. The magnitude and phase of the vibrations may be controlled in dependence on said vibration control signal.

The active vibration control apparatus may also comprise one or more accelerometer. The actuator and the one or more accelerometer may be configured for mounting to a body structure of a vehicle.

The actuator could be used in conjunction with one or more supplementary actuator, such as one or more loudspeaker. The one or more supplementary actuator could be configured to increase or decrease one or more third vibration component. The one or more third vibration component could be at a third frequency range. For example, the third frequency range could be greater than 100Hz.

According to a still further aspect of the present invention there is provided a vehicle comprising an active vibration control apparatus as described herein.

According to a further aspect of the present invention there is provided a method of generating a vibration control signal for an actuator actively to control vibrations. The method may comprise generating a vibration-reducing signal for controlling actuation of the actuator to reduce one or more first vibration component. The method may comprise generating a sound-generating signal for controlling actuation of the actuator to increase one or more second vibration component. The method may comprise combining the vibration-reducing signal and the sound-generating signal to form the vibration control signal.

The vibration-reducing signal and the sound-generating signal could be generated independently of each other and output to an actuator controller. The vibration-reducing signal and the sound-generating signal may be combined by the actuator controller to generate the vibration control signal. Alternatively, the vibration-reducing signal and the sound-generating signal may be combined to generate the vibration control signal which is then output to the actuator controller.

The sound-generating signal may be generated in dependence on an acoustic transfer function.

The vibration-reducing signal may be generated in dependence on an accelerometer signal.

The method may comprise transforming the accelerometer signal from a time-based signal to a frequency-based signal.

The vibration-reducing signal and/or the sound-generating signal may be generated in dependence on a cylinder deactivation cycle of an internal combustion engine.

The one or more first vibration component may relate to one or more first vibration harmonic. The vibration-reducing signal may be operative to control actuation of the actuator to reduce or cancel said one or more first vibration harmonic.

The one or more second vibration component may relate to one or more second vibration harmonic. The vibration-reducing signal may be operative to control actuation of the actuator to increase or reinforce said one or more second vibration harmonic.

Any controller or controllers described herein may suitably comprise a control unit or computational device having one or more electronic processors. Thus the system may comprise a single control unit or electronic controller or alternatively different functions of the controller may be embodied in, or hosted in, different control units or controllers. As used herein the term "controller" or "control unit" will be understood to include both a single control unit or controller and a plurality of control units or controllers collectively operating to provide any stated control functionality. To configure a controller, a suitable set of instructions may be provided which, when executed, cause said control unit or computational device to implement the control techniques specified herein. The set of instructions may suitably be embedded in said one or more electronic processors. Alternatively, the set of instructions may be provided as software saved on one or more memory associated with said controller to be executed on said computational device. A first controller may be implemented in software run on one or more processors. One or more other controllers may be implemented in software run on one or more processors, optionally the same one or more processors as the first controller. Other suitable arrangements may also be used.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a schematic representation of a vehicle incorporating an active vibration control apparatus in accordance with an embodiment of the present invention; Figure 2A shows a first sound map with the active vibration apparatus in accordance with an embodiment of the present invention deactivated; Figure 2B shows a second sound map with the active vibration apparatus in accordance with an embodiment of the present invention activated; and Figure 3 shows a graphical representation of the change in measured vibrations in different locations in the vehicle cabin with the active vibration apparatus activated and deactivated.

DETAILED DESCRIPTION

Active vibration control (AVC) apparatus 1 in accordance with an embodiment of the present invention is described herein with reference to Figure 1. The AVC apparatus 1 is disposed in a vehicle 2, such as an automobile, and is operative actively to control the transmittal of vibrations in a body structure 3 of the vehicle 2. The AVC apparatus 1 is dual function and is adapted to reduce a first vibration component in the body structure 3 and to increase a second vibration component in the body structure 3. The AVC apparatus 1 is operative to control the transmittal of vibrations into a cabin 4 of the vehicle 2.

The vehicle 2 has a powertrain comprising an internal combustion engine 5 disposed in an engine compartment 6. The internal combustion engine 5 comprises a plurality of cylinders and in the present embodiment some of the cylinders may be deactivated when not required to provide improved efficiency. By way of example, the internal combustion engine 5 may comprise two banks each comprising four cylinders, the banks being inclined relative to each other in a v-shaped configuration (commonly referred to as a V8 configuration). The cylinders in one of the banks may be selectively deactivated allowing the internal combustion engine 5 to function as an inline four (14). Similarly, the banks of the internal combustion engine 5 may each comprise three cylinders (a V6 configuration) which may operate selectively as an inline three (13). Other engine configurations are also possible. For example, cylinder deactivation may be performed in an inline engine. A consequence of deactivating some of the cylinders is that the amplitude and/or frequency of the vibrations generated by the internal combustion engine 5 are altered. As a result, the vibrations and/or acoustic waves transmitted into the vehicle cabin 4 may change depending on the operating mode of the internal combustion engine 5. At least in certain embodiments, the resulting change may be undesirable since it provides audio and/or haptic cues to the vehicle occupant(s) that the internal combustion engine 5 is operating in a different mode. Moreover, certain characteristics of the vibrations transmitted into the vehicle cabin 4 may be undesirable in one or more operating mode of the internal combustion engine 5. As described herein, the AVC apparatus 1 is operative actively to modify the vibrations in the body structure 3 to reduce a first component and to increase a second component.

The AVC apparatus 1 comprises a controller 7, an actuator 8 and at least one accelerometer 9. The controller 7 comprises electronic processor 10 coupled to electronic system memory 11. A set of instructions is stored on the system memory 11 which, when executed, cause the electronic processor 10 to perform the method(s) described herein. The actuator 8 (also referred to as a "shaker") is operable to generate vibrations at a controllable magnitude and frequency. The actuator 8 in the present embodiment is an electrodynamic actuator comprising an electromagnet (not shown) operable in response to a vibration control signal SIG generated by the electronic processor 10. The vibration control signal SIG controls the frequency (Hz) and/or force (N) generated by the actuator 8.

The actuator 8 is mounted to a body structure 3 of the vehicle 2. By way of example, the actuator S may be mounted to a portion of the body structure 3 forming a floor panel, a bulkhead or a dashboard panel. In use, the actuator 8 is energized to actively generate vibrations which are transmitted through the body structure 3. The electronic processor 10 is configured to generate a vibration control signal SIG which controls one or more operating parameter of the actuator 8. The vibration control signal SIG controls the actuator 8 to generate vibrations having a predetermined frequency, amplitude and phase. As described herein, the actuator 8 is controlled to generate a vibration signature comprising a vibration-reducing component and a sound-generating component. The vibration control signal SIG is generated by combining a vibration-reducing signal SIGv and a sound-generating signal SIGs. The formulation of the vibration-reducing signal SIG and the sound-generating signal SIGs is described herein.

The accelerometer 9 is connected to the controller 7, for example over a 2-pin or 3-pin lemo connection. The accelerometer 9 is rigidly mounted to the body structure 3 in a location spaced apart from the actuator S. In use, the accelerometer 9 measures the amplitude of vibrations in the body structure 3 with respect to time. The vibrations in the body structure 3 can, for example, be generated by the powertrain, including the internal combustion engine 5. A time-based vibration signal VIBt is output by the accelerometer 9 to the electronic processor 10 in real time. The electronic processor 10 is configured to implement a vibration transform algorithm to decompose the time-based vibration signal VIB, into a frequency-based signal VIBf. The transform algorithm in the present embodiment is in the form of a forward Fourier Transform. The frequency-based signal VI131 is a frequency domain representation of the time-based vibration signal VIBI which is in the time domain. The frequency-based signal VIBf comprises the component frequencies of the time-based signal VIBt and facilitates identification of the harmonic frequencies of the vibrations. By way of example, if the internal combustion engine 5 is operating at 600RPM (corresponding to 1ORPS), the first harmonic f is 10Hz, the second harmonic 2f is 20Hz and so on. The vibration-reducing signal SIG is generated in dependence on the frequency-based signal VIBf and specified engine harmonic. The engine harmonic is used to define the frequencies where vibrations are to be cancelled (or reduced) and the powertrain sound to be enhanced; this may be referred to as engine order cancellation and engine order enhancement. In particular, the vibration-reducing signal SIG is configured to control the actuator 8 to generate vibrations which are in antiphase with the vibrations measured by the accelerometer 9. The vibration-reducing signal SIGv comprises amplitude, frequency and phase components. The vibration-reducing signal SIG specifies the frequency, magnitude and phase of the vibrations to be generated by the actuator 8. It will be appreciated that the frequency of the vibrations to be generated by the actuator 8 is determined in dependence on the engine harmonic to be cancelled. The AVC apparatus 1 may be configured periodically to perform a calibration sequence comprising operating the actuator 8 and using the accelerometer 9 to measure the resultant vibrations in the body structure 3. A vibration transform algorithm may be defined for controlling the force applied by the actuator 8 to generate vibrations of sufficient magnitude to reduce or neutralise the vibrations measured by the accelerometer 9. The calibration sequence may be used to generate a calibration file. The vibration-reducing signal SIG may be generated in dependence on the calibration file.

The sound-generating signal SIGs is generated in dependence on an acoustic transform function. The acoustic transform function defines one or more operating parameter of the actuator 8 to generate vibrations in the body structure 3 suitable for enhancing the acoustics of the internal combustion engine 5 (and optionally also components of the powertrain). The sound-generating signal SIGs comprises frequency, amplitude and phase components. The acoustic transform function in the present embodiment is in the form of a look-up table which defines the operating parameters of the actuator 8 in dependence on one or more operating parameter of the internal combustion engine 5. In the present embodiment, the look-up table defines the operating parameters of the actuator 8 in dependence on the engine speed (RPM), the engine load (N) and optionally also the status of engine cylinder deactivation. The operating parameter(s) of the internal combustion engine 5 is published to a vehicle communication bus (not shown) by an engine control unit 12 and may be read by the electronic processor 10. The acoustic transform function thereby defines the sound-generating signal SIGs for controlling the actuator 8 to generate vibrations for augmenting the sound audible in the vehicle cabin 4 of the vehicle 2. It will be appreciated that the acoustic transform function may be calibrated for different applications, for example for use in conjunction with different internal combustion engines and/or body structures 3.

The electronic processor 10 is configured to combine the vibration-reducing signal SIG and the sound-generating signal SIGs to generate the vibration control signal SIG. The vibration control signal SIG thereby comprises a vibration-reducing component and a sound-generating component. The vibration control signal SIG comprises amplitude, frequency and phase components. The vibration control signal SIG is output to the actuator 8 which operates to generate vibrations which provide the dual function of cancelling certain vibrations whilst generating or amplifying other vibrations to augment the sound audible within the vehicle cabin 4.

A first sound map 100 is shown in Figure 2A representing frequency (Hz) against engine speed (rpm) when the active vibration apparatus 1 is deactivated. A second sound map 110 is shown in Figure 2B representing frequency (Hz) against engine speed (rpm) when the active vibration apparatus 1 is activated. The active vibration apparatus 1 is operative to enhance the sound in the vehicle cabin 4 and the resulting changes are evidenced by a comparison of the first and second sound maps 100, 110. The engine harmonics are apparent in both the first and second sound maps 100, 110 as linear traces, but those in the second sound map 110 at selected frequencies are more pronounced due to augmentation by the actuator 8.

Figure 3 shows a graphical representation 120 of the change in measured vibrations at reference points in the vehicle cabin 4. The reference points are defined in relation to the driver seat and the steering wheel in the illustrated arrangement. A first plot 130 represents the audio power (dB) with the active vibration apparatus 1 deactivated; and a second plot 140 represents the audio power (dB) with the active vibration apparatus 1 activated. A bar chart 150 represents the change (delta.6,) in the measured audio power at each reference point in the vehicle cabin 4.

It will be appreciated that various changes and modifications may be made to the present invention without departing from the scope of the present application. In the embodiment of the AVC apparatus 1 described herein, the electronic processor 10 combines the vibration-reducing signal SIG and the sound-generating signal SIGs to generate the vibration control signal SIG which is output to the actuator 8. In an alternate arrangement, the electronic processor 10 could output the vibration-reducing signal SIGv and the sound-generating signal SIGs as separate signals. The actuator 8 could comprise a control unit which combines the vibration-reducing signal SIG and the sound-generating signal SIGs to form the vibration control signal SIG.

Furthermore, the accelerometer 9 could be used to establish a feedback loop. For example, the measurements made by the accelerometer 9 could be used to determine a relationship between operation of the actuator 8 and vibrations transmitted in the body structure 3.

Claims

CLAIMS: 1. An apparatus (1) for a vehicle (2), the apparatus (1) comprising: a controller (7) comprising at least one electronic processor (10) having an electrical output for outputting a vibration control signal (SIG) to control operation of an actuator (8); an electronic memory device (11) electrically coupled to the at least one electronic processor (10) and having instructions stored therein; wherein the at least one electronic processor (10) is configured to access the memory device and execute the instructions stored therein such that it is operable to generate the vibration control signal (SIG); wherein the vibration control signal (SIG) is generated by combining a vibration-reducing signal (SIGv) for controlling actuation of the actuator (8) to reduce one or more first vibration component, and a sound-generating signal (SIGs) for controlling actuation of the actuator (8) to increase one or more second vibration component.
2. An apparatus (1) as claimed in claim 1, wherein the at least one electronic processor (10) is configured to generate said sound-generating signal (SIGs) in dependence on an acoustic transfer function.
3. An apparatus (1) as claimed in claim 2, wherein the acoustic transfer function comprises a look-up table defining the sound-generating signal (SIGs) for engine speed and/or engine load.
4. An apparatus (1) as claimed in any one of claims 1, 2 or 3, wherein the vibration-reducing signal (SIG) is generated in dependence on an accelerometer (9) signal.
5. An apparatus as claimed in claim 4, wherein the at least one electronic processor (10) is configured to apply a transform to the accelerometer (9) signal to generate the vibration-reducing signal (SIG4-
6. An apparatus as claimed in claim 5, wherein the transform decomposes the accelerometer (9) signal from a time-based signal into a frequency-based signal.
7. An apparatus (1) as claimed in any one of the preceding claims, wherein the vibration-reducing signal (SIGv) is generated in dependence on one or more operating parameter of the internal combustion engine (5).
8. An apparatus (1) as claimed in any one of the preceding claims, wherein the sound-generating signal (SIGs) is generated in dependence on one or more operating parameter of the internal combustion engine (5).
9. An apparatus (1) as claimed in claim 7 or claim 8, wherein the internal combustion engine (5) comprises a plurality of cylinders and one or more of said cylinders may be selectively deactivated, the at least one electronic processor (10) being configured to generate said vibration-reducing signal (SIGv) and/or said sound-generating signal (SIGs) in dependence on activation and/or deactivation of one or more of said cylinders.
10. An apparatus (1) as claimed in claim 9, wherein the sound-generating signal (SIGs) is generated to augment sound generated by the internal combustion engine (5) when one or more of said cylinders is deactivated.
11. An apparatus (1) as claimed in any one of the preceding claims, wherein the one or more first vibration component is in a first frequency range from 10Hz to 100Hz; and the one or more second vibration component is in a second frequency range from 50Hz to 100Hz.
12. An apparatus (1) as claimed in any one of the preceding claims comprising said actuator (8).
13. A vehicle (2) comprising an apparatus as claimed in any one of the preceding claims.
14. A method of generating a vibration control signal (SIG) for an actuator (8) actively to control vibrations, the method comprising: generating a vibration-reducing signal (SIG) for controlling actuation of the actuator (8) to reduce one or more first vibration component; generating a sound-generating signal (SIGs) for controlling actuation of the actuator (8) to increase one or more second vibration component; and combining the vibration-reducing signal (SIG) and the sound-generating signal (SIGs) to form the vibration control signal (SIG).
15. A method as claimed in claim 14 comprising generating said sound-generating signal (SIGs) in dependence on an acoustic transfer function.
16. A method as claimed in claim 14 or claim 15, wherein the vibration-reducing signal (SIGv) is generated in dependence on an accelerometer (9) signal.
17. A method as claimed in claim 16 comprising transforming the accelerometer (9) signal from a time-based signal to a frequency-based signal.
18. A method as claimed in any one of claims 14 to 17 comprising generating the vibration-reducing signal (SIGv) and/or the sound-generating signal (SIGs) in dependence on a cylinder deactivation cycle of an internal combustion engine (5).
19. A method as claimed in any one of claims 14 to 18, wherein the one or more first vibration component is in a first frequency range from 10Hz to 100Hz; and the one or more second vibration component is in a second frequency range from 50Hz to 100Hz.
20. An active vibration control apparatus (1) substantially as herein described with reference to the accompanying figures.