Assembly and method for actively controlling the rolling noise of a motor vehicle

Abstract

An assembly (1) for actively controlling the rolling noise of a motor vehicle, the assembly comprising a trajectory control device (2) and an anti-noise device (3), the trajectory control device comprising a further sensor (22, 22') fixed to a steering knuckle (20, 20'), such as an accelerometer, the trajectory control device (2) being able to transmit to the anti-noise device (3) a measurement obtained by the further sensor (22, 22'), and the anti-noise device being able to generate an anti-noise signal depending on the obtained acceleration measurement and to control the emission of the anti-noise signal via a loudspeaker (31).

Description

Technical Field

[0001] This invention relates to a component and method for actively controlling rolling noise in a motor vehicle. Background Technology

[0002] In the automotive industry, the implementation of active noise control methods is well-known. These methods generate anti-noise signals that can reduce noise pollution in the vehicle's passenger compartment.

[0003] In particular, structural noise generated by the rolling of motor vehicles on the road causes structural vibrations and thus audible noise in the passenger cabin, which can be particularly annoying to users.

[0004] To generate active noise control signals to compensate for noise pollution from motor vehicles, it is known that noise-resistant signals can be generated based on reference and error signals by adjusting commands, such as well-known methods. feedback Adjust or Feedforward adjust.

[0005] Document EP2239728A2 is particularly well-known, disclosing a system for active noise control based on audio system output, wherein the system generates an anti-noise signal emitted by the passenger cabin audio system based on sensors (such as accelerometers) installed on the vehicle.

[0006] However, one problem with this solution is that sensors capable of providing reference signals must be installed, which is relatively expensive and relatively complex to implement on existing motor vehicle architectures.

[0007] In practice, adding sensors to motor vehicles requires available mounting volume, available mounting points, and additional wiring. However, obtaining available mounting points within the architecture of a motor vehicle is a relatively significant challenge.

[0008] Therefore, an active noise control component that can solve the above problems is needed. Summary of the Invention

[0009] To this end, a component for actively controlling rolling noise of a motor vehicle is proposed. The component includes a trajectory control device and a noise reduction device. The trajectory control device includes at least one wheel speed sensor fixed to the steering knuckle of the wheel of the motor vehicle, and the noise reduction device is capable of commanding at least one speaker installed in the passenger compartment of the motor vehicle.

[0010] The trajectory control device includes additional sensors fixed to the steering knuckle, and the trajectory control device is designed to transmit the measurements obtained by the additional sensors to the noise reduction device;

[0011] The noise reduction device is designed to generate a noise reduction signal based on the measurements from the additional sensor and to command the transmission of the noise reduction signal via the speaker.

[0012] Therefore, a high-performance active noise control system can be obtained, which can be adapted to existing vehicle architectures without generating additional volume and weight.

[0013] The sensor mounted on the steering knuckle can also measure the source of rolling noise very well with high coherence, namely the tire / road contact point, because it is very close to this contact point.

[0014] In other words, the sensors mounted on the steering knuckle provide a very high-quality signal for controlling rolling noise according to coherence standards, thereby achieving a significant gain in noise reduction performance.

[0015] Advantageously and non-limitingly, for each wheel of the motor vehicle, the trajectory control device includes a speed sensor mounted on the steering knuckle associated with said wheel, characterized in that for each wheel, the trajectory control device also includes additional sensors mounted on said associated steering knuckle; the trajectory control device is designed to transmit the measurements obtained by each of said additional sensors to the noise reduction device, the noise reduction device being designed to command these speakers to emit noise reduction signals based on the measurements obtained from each of said additional sensors.

[0016] Therefore, the noise generated in the passenger compartment by the rolling of each wheel on the passenger compartment can be considered to improve active noise cancellation.

[0017] Advantageously and non-limitingly, the at least one additional sensor includes an accelerometer, such as a triaxial accelerometer, or includes an angular velocity sensor, such as a gyroscope, or includes a laser sensor. This allows the vibrational dynamics of the wheel on the road to be considered in a relatively complete manner, thereby enabling the acquisition of a relatively robust reference signal.

[0018] Advantageously and non-limitingly, the additional sensor is designed to sample the measurements obtained from the associated steering knuckle at a frequency greater than or equal to 2000 Hz. This avoids the need for an anti-aliasing filter before the digitized signal. Such an anti-aliasing filter comes at the cost of signal delay and latency. This unfiltered sampling thus ensures better system performance. In fact, such a sampling frequency is sufficient to guarantee robustness when taking into account the vibrational dynamics of rolling, while still maintaining negligible spectral aliasing for noise control below 300 Hz.

[0019] Advantageously and non-limitingly, the trajectory control device communicates with the noise reduction device via a low-latency communication bus, for example, with a maximum delay of one or two samples. This allows for rapid transmission of the reference signal, enabling effective active noise reduction.

[0020] Advantageously and non-limitingly, the communication bus is designed to transmit the measurements obtained by the additional sensors at a frequency at least equal to the sampling frequency of the additional sensors. This ensures that data is not resampled when transmitting data from the trajectory control device to the noise immunity device.

[0021] Advantageously and non-limitingly, the component includes at least one microphone in the passenger compartment of the motor vehicle, the at least one microphone being capable of picking up ambient noise present in the passenger compartment to be reduced; the noise reduction device is designed to also command the speakers to emit noise reduction signals based on the ambient noise picked up by the at least one microphone. Therefore, the microphone can implement feedback loop control, commonly referred to as... feedback The error signal is obtained from the microphone.

[0022] The present invention also relates to a method for actively controlling rolling noise of a motor vehicle, the method being implemented by a noise reduction device of the aforementioned components, comprising the following steps:

[0023] Receive at least one set of sampled values ​​of measurements acquired by the additional sensors of the trajectory control device;

[0024] Generate an anti-noise signal based on the received sampled values; and

[0025] The noise-resistant signal is emitted by the loudspeaker of the noise-resistant device.

[0026] Advantageously and non-limitingly, the noise-resistant signal is obtained through a feedforward command (also known as a feedforward command, referred to as...). Feedforward The signal is generated in a manner that includes a reference signal corresponding to all sampled measurements from the additional sensor, and at least one error signal provided by sampling at least one sound obtained from at least one microphone within the passenger compartment of the vehicle. This allows for a relatively efficient and robust noise-resistant signal.

[0027] The present invention also relates to a motor vehicle comprising the components described above, wherein the noise reduction device implements the method described above. Attached Figure Description

[0028] Other features and advantages of the invention will become apparent when reading the following description of a specific embodiment of the invention, provided by way of indication rather than limitation, with reference to the accompanying drawings:

[0029] Figure 1 This is a schematic diagram of a motor vehicle including components according to the present invention;

[0030] Figure 2 It is by Figure 1 A flowchart of a method for implementing a noise reduction device for a component;

[0031] Figure 3 This is implemented as per the noise reduction device according to the invention. Feedforward A diagram illustrating the control mechanism.

[0032] because Figure 1 and Figure 3 The same embodiment of the invention is involved, and therefore they will be explained simultaneously. Detailed Implementation

[0033] like Figure 1 As shown, the motor vehicle includes an active noise control component 1 for actively controlling the noise in the passenger compartment of the motor vehicle.

[0034] The present invention relates in particular to the active control of noise caused by wheel vibrations while driving on a road, which are transmitted throughout the vehicle’s structure and generate noise in the passenger compartment through fluid / structural connections.

[0035] To control and reduce this noise, component 1 first includes a trajectory control device 2 for the motor vehicle, and also includes a noise reduction device 3.

[0036] Track control device 2 (also known as ESP ,express Electronic stability program In particular, it allows vehicles to stay on the correct trajectory even when they lose traction.

[0037] For each wheel 10, 10' of the motor vehicle, the trajectory control device 2 specifically includes wheel speed sensors 21, 21' that are typically mounted on the steering knuckles 20, 20' of the corresponding wheels 10, 10'.

[0038] In fact, mounting speed sensors 21, 21' on steering knuckles 20, 20' of the drive shaft (usually located at the front) exhibits good coherence with certain structural noises originating from the powertrain.

[0039] In fact, the transmission connects the powertrain and the steering knuckles 20, 20'; they transmit engine torque (which is their primary function), but also transmit vibrations from the powertrain. Therefore, this invention is also effective in reducing certain noises from the powertrain.

[0040] In existing motor vehicles, the trajectory control device 2 is independent and not connected to the noise suppression device 3, and its function is remote.

[0041] The noise reduction device 3 here is an active noise cancellation device, also known as ANC, which means... Active noise control .

[0042] Various types of active noise cancellation devices are known in the prior art.

[0043] This invention is not intended to describe the precise operation of a particular type of active noise control, the principle of which is based on the interference between two waves, as is well known to those skilled in the art.

[0044] Various types of noise control are known for this type of noise suppression device. Open-loop regulation is particularly known, which is performed without an error sensor but using a reference signal from the source. feedback Control is also known, where regulation is performed based on corrections to the error signal, and Feedforward Control is also known, where correction is based on error signals and reference signals.

[0045] In the context of noise immunity control aimed at reducing structural rolling noise of motor vehicles, only Feedforward Only through control can satisfactory results be achieved.

[0046] Rolling noise is random, making it unpredictable, unlike engine noise, whose harmonic phases and amplitudes evolve more slowly.

[0047] Engine noise has a relatively narrow spectrum, while rolling noise has a wider spectrum.

[0048] Therefore, in the context of active structural rolling noise reduction, only Feedforward Only through control can satisfactory results be achieved.

[0049] However, Feedforward Control requires not only the coherence of the reference signal x and the error signal e (which is relatively complex in the case of random signals), but also the measurement time constraints of these signals.

[0050] exist Feedforward The control system needs to obtain a reference signal x corresponding to the source of the noise and an error signal e corresponding to the remaining noise after processing.

[0051] For this purpose, component 1 includes at least one microphone 32, 32', 32'', for example, three microphones, to detect the error signal e.

[0052] These microphones 32, 32', and 32'' are installed in the passenger cabin, although they are shown in... Figure 1They are installed in the upper part, but they can also be installed in other locations in the passenger compartment, especially in the lower part, in order to pick up noise that still exists after noise reduction.

[0053] The reference signal x is a measurement of the vehicle structure vibration propagating from the wheels.

[0054] For each wheel, in addition to speed sensors 21, 21', the trajectory control device 2 also includes sensors 22, 22' integrally mounted with the steering knuckles 20, 20' of each wheel 10, 10', which in this particular embodiment are accelerometers 22, 22', particularly triaxial accelerometers.

[0055] In particular, these sensors 22, 22' are integrated into speed sensors 21, 21', which eliminates the need to fix them separately, thus solving the problem of sensor fixing points on the structure of motor vehicles.

[0056] However, the present invention is not limited to accelerometers as sensors, but relates to any type of sensor integrated into the trajectory control device and fixed to the steering knuckles 20, 20'.

[0057] In particular, laser sensors for measuring road roughness or the relative displacement between two surfaces of a wheel bearing also provide particularly relevant reference signals and can be integrated into wheel speed sensors 21, 21'. The position and shape of speed sensors 21, 21' make them particularly suitable for carrying such laser sensors for measuring displacement of bearing surfaces on the rotating side, since the magnetic target for measuring wheel speed is mounted precisely on this surface. According to a particular embodiment of the invention, a gyroscope can also be installed in the trajectory control device for each wheel, which can be integrated into speed sensors 21, 21', for example, as a supplement to accelerometers and / or radar.

[0058] Each gyroscope provides an additional reference signal that can improve active noise reduction. However, the increase in this additional data requires that the communication bus 5 be designed to transmit this data fast enough.

[0059] Therefore, for each wheel, in addition to speed sensors 21, 21', the trajectory control device 2 also includes accelerometers 22, 22', particularly triaxial accelerometers, which are integrally mounted with the steering knuckles 20, 20' of each wheel 10, 10'.

[0060] This installation of the accelerometer allows for reliable measurement of wheel vibrations on the road, while still being able to pick up the wave as early as possible before it propagates into the passenger compartment.

[0061] In fact, FeedforwardIn the ANC system, the noise immunity signal is generated by convolving the noise measured by microphones 32, 32', 32'' with the reference signal obtained by accelerometers 22, 22'.

[0062] The noise-canceling device 3 that generates the noise-canceling signal and emits it from the speaker 31 installed in the passenger compartment of the vehicle has an attenuation effect, which tends to cancel out unwanted noise.

[0063] Therefore, the noise immunity signal should arrive at the error signal microphones 32, 32', 32'' earlier than the unwanted noise propagating from the wheels to the passenger compartment.

[0064] Therefore, refer to Figure 3 The total delay of the reference path 300, including noise controller 302 and secondary path 303, should be less than the delay of the primary path 301 (corresponding to the sound propagation from the wheels to the passenger compartment), and the sum 304 corresponds to the error picked up by error microphones 32, 32', and 32''. This is a causal constraint; if this condition is not met, then... Feedforward The ANC system cannot properly reduce unwanted noise.

[0065] To ensure this causal constraint, the acceleration measured by accelerometers 22, 22' is sampled at a relatively high frequency (preferably greater than 2000 Hz). Such high-frequency raw sampling (in other words, unfiltered sampling) thus avoids the use of anti-aliasing low-pass filters, which are detrimental to time delay, as filters always introduce a phase shift and therefore a delay. In fact, at such frequencies, spectral aliasing errors are negligible for noise control below 300 Hz.

[0066] The acceleration signals are first picked up by the trajectory control device 2 using the conventional transmission bus of the trajectory control device 2, and these signals are then sent to the noise suppression device 3.

[0067] To ensure rapid transmission, a low-latency communication bus 5 is installed between the trajectory control device 2 and the noise reduction device 3.

[0068] For a digital bus as implemented in this invention, low latency is understood to mean one or at most two latency samples for a frequency greater than or equal to 2000 Hz.

[0069] The communication bus 5 is specifically designed to transmit data at a frequency at least equal to the sampling frequency of the accelerometer.

[0070] The communication is also optimized by the communication bus 5 through the transmission of unfiltered raw data.

[0071] Each accelerometer 22, 22' is associated with three axes in this embodiment, and the vehicle in this embodiment includes four wheels 10, 10', with a total of 12 sampling signals to be transmitted between the trajectory control device 2 and the noise reduction device 3.

[0072] The noise suppression device 3 then implements a method comprising first receiving a 201 sampling signal, generating a 202 noise suppression signal, and then transmitting a 203 noise suppression signal through a speaker 31 in the passenger cabin.

[0073] noise immunity signal through Feedforward The control generates 202 based on samples of one or more signals from one or more error microphones 32, 32', 32'' and the received reference signal x.

Claims

1. A component (1) for actively controlling rolling noise of a motor vehicle, the component comprising a trajectory control device (2) and a noise reduction device (3), the trajectory control device comprising at least one wheel speed sensor (21, 21') fixed to a steering knuckle (20, 20') of the drive axle of the motor vehicle, and the noise reduction device being capable of commanding at least one speaker (31) installed in the passenger compartment of the motor vehicle, characterized in that, The trajectory control device (2) includes at least one accelerometer (22, 22') fixed to the steering knuckle (20, 20'), the trajectory control device (2) being designed to transmit measurements obtained by the accelerometer (22, 22') to the noise suppression device (3); wherein the accelerometer (22, 22') is designed to sample the measurements obtained from the associated steering knuckle (20, 20') at a frequency greater than or equal to 2000 Hz, the trajectory control device (2) communicating with the noise suppression device (3) via a low-latency communication bus (5), the communication bus (5) being designed to transmit the measurements obtained by the accelerometer (22, 22') at a frequency at least equal to the sampling frequency of the accelerometer; the noise suppression device (3) is designed to generate an anti-noise signal based on the original measurements obtained from the accelerometer (22, 22') and command the transmission of the anti-noise signal via the speaker (31).

2. The component (1) as claimed in claim 1, wherein, For each wheel (10, 10') of the motor vehicle, the trajectory control device includes a speed sensor (21, 21') mounted on the steering knuckle (20, 20') associated with the wheel (10, 10'), characterized in that for each wheel (10, 10'), the trajectory control device also includes an accelerometer (22, 22') mounted on the associated steering knuckle (20, 20); the trajectory control device (2) is designed to transmit the measurement value obtained by each of the accelerometers (22, 22') to the noise reduction device (3); the noise reduction device (3) is designed to command the loudspeaker (31) to emit an anti-noise signal based on the measurement value obtained from each of the accelerometers (22, 22').

3. The component (1) as described in claim 1 or 2, characterized in that, The accelerometer (22, 22') is a triaxial accelerometer.

4. The component (1) as claimed in claim 1 or 2, characterized in that, The maximum latency of the low-latency communication bus (5) is one or two samples.

5. The component (1) as claimed in claim 1 or 2, characterized in that, The component includes at least one microphone (32, 32', 32'') in the passenger compartment of the motor vehicle, which is capable of picking up ambient noise present in the passenger compartment to be reduced; the noise reduction device (3) is designed to also command the speakers (31) to emit noise reduction signals based on the ambient noise picked up by the at least one microphone (32, 32', 32'').

6. A method for actively controlling rolling noise of a motor vehicle, the method being implemented by a noise-resistant device (3) of component (1) as described in any one of claims 1 to 5, characterized in that, The method includes the following steps: - Receive (201) at least one set of sampled values ​​of the measurements acquired by the accelerometer (22, 22') of the trajectory control device; - Generate an anti-noise signal (202) based on the received sampled values; and - The noise-resistant signal is emitted (203) via the loudspeaker of the noise-resistant device.

7. The method as described in claim 6, characterized in that, The noise immunity signal is generated by a feedforward command (202), wherein the reference signal corresponds to all sampled measurements from the accelerometer (22, 22'), and the error signal is provided by sampling the sound obtained from the microphone (32, 32', 32'') in the passenger compartment of the vehicle.

8. A motor vehicle comprising the component (1) as claimed in any one of claims 1 to 5 and implementing the method as claimed in claim 6 or 7.

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