Patent Description:
The present invention can, in principle, be used in connection with any type of vehicle for road use, in particular a motorized vehicle, such as a (passenger) car, lorry / truck, bus or coach. Given that the invention finds particular application in (passenger) cars, the invention will be described primarily in connection with cars, without being limited to this. In particular, one skilled in the art will not have any difficulties, guided by the present disclosure, to implement the invention in the context of vehicles other than cars.

A large number of people experience motion sickness (also referred to as kinetosis, among other names) when travelling in a vehicle. Typically, this problem is exacerbated if the person travelling in the vehicle and susceptible to motion sickness (in the following simply "person" or "user") looks at an object within the vehicle, in particular an object which is substantially still with respect to the vehicle, while the vehicle may accelerate and decelerate, both in a longitudinal direction (i.e. the main direction of travel) or in a transverse direction, for example when the vehicle passes through a curve or makes a turn (lateral acceleration) or passes over a speed bump or other uneven road surface etc. (vertical acceleration) or combinations thereof. As used herein, the term "acceleration", "accelerate" and similar is preferably intended to be understood to encompass not only acceleration, but also deceleration (effectively a negative acceleration), in any direction, unless the context specifies otherwise.

<CIT> discloses a system for visually indicating an anticipated acceleration of an autonomously driving vehicle to a person travelling in the vehicle. Information regarding the anticipated acceleration is derived from a navigation system of the autonomously driving vehicle. This document also briefly mentions the possibility of indicating the anticipated acceleration by means of an acoustic signal, however without disclosing any details regarding this idea.

<CIT> discloses a feedback system that alters the distribution of a sound in a vehicle from a default configuration indicating to the driver that his action is dangerous or inefficient. The feedback system monitors one or more forces or accelerations such as speeding up, slowing down, changing the vehicle's direction, etc..

<CIT> discloses a vehicle sound synthesis system with a loudspeaker and a controller. The loudspeaker projects sound indicative of synthesized engine noise (SEN) within a cabin of a vehicle in response to receiving a SEN signal.

<CIT> discloses a pseudo sound signal generating unit which generates pseudo engine sound signals on the basis of the traveling information of a vehicle obtained by means of an acquisition unit.

It is an object of at least some embodiments of the present invention to provide an alternative technique of providing an indication of an acceleration of a vehicle, in particular an improved technique of providing an indication of an acceleration of a vehicle.

In a first aspect, the present disclosure provides a system for providing an indication of an acceleration of a vehicle for road use, the system comprising:.

In the sense of the invention, the term "actual acceleration" refers not simply to a theoretical value of acceleration that the vehicle may achieve (sometimes expressed in terms of time taken to accelerate from <NUM> to <NUM> per hour), but a current, actual acceleration of the vehicle in a physical sense. It is however to be appreciated that the term "actual acceleration" as detected by the detector does not need to be a value which (directly) provides the correct measurement of the actual acceleration as expressed in (correct) physical units, such as a value expressed in m/s<NUM>. Instead, the term "actual acceleration" can, in principle, mean any information which (at least approximately) characterises the acceleration of the vehicle, in particular (at least approximately) uniquely characterises the acceleration of the vehicle, in particular a value or set of values from which the physically correct measurement of the actual acceleration can (at least approximately) be obtained, in particular without having to resort to other measurements. The actual acceleration as detected by the detector may in particular comprise a numerical value or values, in particular a set of two, three or more values (e.g. one value for each Cartesian direction), in particular a vector or information representing a vector. In particular, the actual acceleration as detected by the detector would be such that a computing device can process it.

Suitable detectors for detecting the actual acceleration of the vehicle are known in the art and include, for example, accelerometers and gyroscope sensors or combinations of these.

In the sense of the invention, a "processing unit" is preferably intended to be understood to mean any electrical component or device which can receive a detection output from the detector and generate a control signal based thereon which can be used by the acoustic output device. The processing unit can either (substantially) transparently pass the detection output to the acoustic output device if the latter can be controlled directly by the detection output. The processing unit may however process the detection output and generate a control signal which is (substantially) different from the detection output. The processing unit may in particular comprise a microprocessor. The processing unit of the first aspect of the present disclosure may, for example, comprise an onboard computer of the vehicle, or a component thereof.

Examples of acoustic output devices will be described below. Whilst the audible sound needs to be appreciable by a person, it does not necessarily need to be particularly loud. In particular, it may be output in addition to other sounds that can be heard in the vehicle, and the (average and/or peak) volume of the audible sound may be lower than the (average and/or peak) volume of such other sounds. The audible sound may be output by an acoustic output device which also outputs such other sounds, or it may be output by a different acoustic output device. Also, the audible sound may be a sound which, in the absence of any actual acceleration of the vehicle, would not be output by the acoustic output device, or it may be a modification of a sound which, even in the absence of any actual acceleration of the vehicle, would be output by the acoustic output device.

The system can be built into the vehicle or may form part of the vehicle. However, the system can also be provided on its own and, for example, be supplied to vehicle manufacturers so that the system may be built into vehicles.

Some embodiments of the first aspect of the present disclosure will now be described.

In some embodiments, the system is configured to modulate the audible sound with, or as a function of, the control signal.

In this way, the person can easily appreciate a (direct) correlation between the acceleration of the vehicle and the audible sound, which may help to alleviate the effects of motion sickness. For example, the modulation may be such that a physical property of the audible sound is varied linearly with a measure of the actual acceleration of the vehicle. However, the correlation between the measure of the actual acceleration and the physical property of the audible sound does not need to be linear. Instead, the physical property of the audible sound may vary as a function of the actual acceleration in such a way that it increases at a greater than linear rate, or alternatively at a smaller than linear rate. In any event, it is preferred that the correlation between the physical property of the audible sound and the actual acceleration is such that it can be represented by a monotone function, in particular a strict monotone function.

In some embodiments, the system is configured to modulate the audible sound with, or as a function of, the control signal in terms of frequency and/or volume and/or another property of the audible sound.

A modulation in terms of frequency and/or volume of the audible sound based on the actual acceleration can provide the person with an effective indication of the actual acceleration of the vehicle, in particular one that is easily recognised or "felt" as an indication of the actual acceleration of the vehicle. In addition, or as an alternative, other properties of the audible sound can also be modulated, such as a waveform of the audible sound.

In some embodiments, the audible sound is an audible sound arranged to be generated by the vehicle.

This may be particularly useful in connection with electric vehicles since they tend to be quieter than vehicles with an internal combustion engine, in particular when they are stationary. The audible sound may therefore be a (subtle) sound that is (artificially) generated or added to give the person an indication of the condition of the vehicle (operational/moving etc.). As indicated above, such a sound may be generated and output regardless of whether the vehicle undergoes any acceleration or not. The latter case may occur for example after the person has put the vehicle into an "activated state", e.g. by inserting a key, key card or similar into an appropriate receptacle of the vehicle or has pressed a start button or similar and while the vehicle remains stationary. Likewise, a condition without acceleration can be a case where the vehicle is moving in a straight line at a constant speed.

An audible sound of the type described above may however also be generated and output in connection with a vehicle which is equipped with an internal combustion engine, for example in a vehicle with noise cancellation function, where the noise generated by the engine might not (easily) be heard within the vehicle.

In the embodiments described above, the sound intended to provide the person with an indication of the condition of the vehicle (operational/moving etc.) can then be modified/modulated depending on the actual acceleration, for example by an increased volume of such a sound, or by superimposing another sound.

In some embodiments, the audible sound is composed of a sound of one or more musical instruments or processed versions thereof, wherein the processing unit is preferably configured to modify the sound to be output, by the acoustic output device, by:.

Adding or removing or modulating the sound of a (further) musical instrument or a processed version thereof may also provide the person with an indication of the condition of the vehicle in terms of acceleration. Adding or removing the sound of a musical instrument or a processed version thereof may leave other physical properties of the audible sound (such as volume and/or frequency) the same, or may be used in addition to a modification in terms of such other physical properties.

As merely one example, the sound of a drum roll could be generated/added when the vehicle passes over an uneven road surface, such as an unsurfaced road (gravel road or similar), where a significant amount of vertical acceleration (up and down, in particular in close succession) would be expected to be experienced.

As one other example, in a steady state of the vehicle (travelling in a straight line at a constant speed), the sound of string instruments could be generated by the vehicle, and when an acceleration (e.g. a positive acceleration in a forward direction) is detected, the sound of another instrument could be added, e.g. a percussion instrument or a brass instrument.

In some examples, that are not part of the claimed invention, the acoustic output device comprises, or forms part of, one or more loudspeakers of the vehicle, in particular a surround sound system of the vehicle, in particular with a noise cancellation function.

Such loudspeakers would typically be permanently installed in the vehicle. Pursuant to the present example, surround sound systems installed in the vehicle may comprise as few as three loudspeakers, but preferably more, for example at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> loudspeakers. They may have (significantly) more than ten loudspeakers, for example at least <NUM>, <NUM>, <NUM> or <NUM>.

In the embodiment of the invention, the acoustic output device comprises, or forms part of, a portable device, in particular a portable device that is proprietary to the vehicle, or a personal device, in particular a smartphone, a laptop computer, a tablet computer, headphones or a headset.

Whether the acoustic output device is proprietary to the vehicle or not, it (or portions thereof) may be removable (from the vehicle). For example, in the case of a device proprietary to the vehicle, the vehicle may include a holder or cradle or similar for carrying the portable device. Such a cradle may, for example, be provided on the back of a headrest (of a front seat) for use by a person sitting on a seat behind that headrest. However, other locations are also possible. When the portable device is placed in the holder or cradle, it is substantially fixed with respect to the vehicle. However, it can be removed from the holder or cradle (and may or may not still be attached to the vehicle via a cable or similar). It may be proprietary to the vehicle in the sense that it may have proprietary connectors which (typically) only fit a corresponding connector of the holder or cradle, or the communication protocols of the holder or cradle (of the vehicle) need to match those of the portable device, so that a generic device (such as a personal mobile device) might not be able to communicate with the vehicle via the holder or cradle.

There are examples, that are not part of the claimed invention, in which no holder or cradle is provided in connection with a proprietary device. Again, the device may be proprietary to the vehicle in the sense that the communication protocols of the portable device need to match those of the vehicle in order to be able to communicate with the vehicle, whereas a generic device (such as a personal mobile device) might not be able to communicate with the vehicle.

Whether the acoustic output device is proprietary to the vehicle or is a (generic) personal device, it may be connected to the vehicle in a wired or wireless manner, for example via Bluetooth® or similar.

In the embodiment of the invention in which the acoustic output device comprises a portable device, the processing unit is arranged to cause the acoustic output device to output the audible sound in such a way that a user of the acoustic output device perceives the audible sound as coming from a substantially consistent direction and/or location relative to the vehicle, irrespective of the location and/or orientation of the acoustic output device relative to the vehicle.

These embodiments are based on the following recognition by the inventor: If an audible sound is output in order to reduce the effects of motion sickness, this can be particularly effective if the audible sound is output (or perceived to come) from a consistent direction with respect to the vehicle. For example, if the audible sound is intended to imitate the sound of an internal combustion engine which, in many vehicles in use today, is located near the front of the vehicle, in a central position, the system can be set up such that the audible sound is output in such a way that the sound is perceived by a user as coming from a central position at the front of the vehicle.

This will briefly be illustrated by way of example. We assume that a user is sitting on the front right-hand seat of the vehicle, is facing forward (in the longitudinal direction of the vehicle) and is wearing a headset with surround sound function. The central position at the front of the vehicle might be at a position which corresponds to a direction, with respect to that user, at <NUM> o'clock (assuming that <NUM> o'clock corresponds to a direction straight ahead, <NUM> o'clock corresponds to a direction to the left and so on). Now, if, for example, the user turns their head <NUM>° to the left, the central position at the front of the vehicle might now be at a position which corresponds to a direction, with respect to that user, at <NUM> o'clock. In order to ensure that the user can perceive the audible sound as coming from a consistent direction, with respect to the vehicle, the system can take the position and/or orientation of the portable device - here the headset of the user - into account. To this end, in some embodiments, the system comprises an interface for receiving information regarding the position and/or orientation of the portable device relative to the vehicle, and the processing unit is arranged to generate the control signal as a function of this information. Using this control signal, the portable device is then "instructed" accordingly, i.e. such that the user can perceive the audible sound as coming from the central position at the front of the vehicle.

In such embodiments, the portable device could itself provide the information regarding the position and/or orientation of the portable device relative to the vehicle, for example using gyroscopes of the portable device and/or positional information obtained with the aid of a (satellite-based) positioning system such as GPS. This information can then be processed by the system, in particular the processing unit. In particular, the system/processing unit can compare this information with information regarding the position and/or orientation of the vehicle so as to determine the position and/or orientation of the portable device relative to the vehicle. In addition, or as an alternative, the vehicle could obtain the information regarding the position and/or orientation of the portable device relative to the vehicle using e.g. one or more cameras or other detectors (installed in the vehicle) arranged to detect the position and/or orientation of the portable device.

The interface for receiving information regarding the position and/or orientation of the portable device relative to the vehicle may be wired or wireless. A wired interface may, for example, be an electrical connector for connection to the portable device. If the portable device is hard-wired to the processing unit, the interface may be regarded as a point along the connection between the processing unit and the portable device.

In alternative embodiments, the processing unit provides, to the portable device, information regarding the direction/position (with respect to the vehicle) which the audible sound is supposed to be perceived to originate from. This information is provided to the portable device without the processing unit necessarily being aware of the position and/or orientation of the portable device relative to the vehicle. Using this information, the portable device can then determine, on the basis of its own knowledge of its own position and/or orientation, how to generate and output the audible sound so that the audible sound is able to be perceived by the user as coming from the "correct" direction/position.

In the sense of the invention, the expressions "correct direction/position" and "substantially consistent direction relative to the vehicle" and similar are preferably intended to be understood in such a way that an angular difference between, on the one hand, the direction which the audible sound is supposed to be perceived to originate from, and, on the other hand, the direction from which the audible sound will be perceived, by a user, to be coming from, is at most, or less than, one of: <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>° or <NUM>°.

In some embodiments, the acceleration comprises any one, or all, or any subset, of longitudinal acceleration, vertical acceleration, lateral acceleration, a right curve, a left curve or road unevenness.

For this purpose, the system may be (permanently) (pre)configured in a corresponding manner, or such that it can be (re)configured, in particular by a user. For example, a user might decide that the system should only output the audible sound in case of longitudinal acceleration and curves to the right and left, but not for other types of acceleration (vertical acceleration or road unevenness) and can adjust the system accordingly. It is also conceivable that different users can adjust settings of the system according to their individual needs, in particular if at least one user uses a portable device such as a headset or headphones. That is, the first user may for example specify (and configure the system accordingly) that an audible sound is provided to the first user for all types of acceleration, whereas a second user may for example specify (and configure the system accordingly) that an audible sound is provided to the second user only for a subset of these types of acceleration.

In some embodiments, the processing unit is arranged to classify the type of acceleration, in particular using a classification algorithm. This makes it easier to distinguish between the different types of acceleration such as longitudinal acceleration, vertical acceleration, lateral acceleration, a right curve, a left curve or road unevenness.

In some embodiments, the processing unit is further configured to generate the control signal in dependence upon the type of acceleration detected by the detector, in particular on the basis of the classification by the processing unit.

For example, the processing unit might be configured such that the control signal to be generated by the processing unit, in the case of (positive) longitudinal acceleration, will cause the volume and frequency of the audible sound to be output by the acoustic output device to increase, whereas, in the case of the vehicle passing through a left or right curve, the audible sound to be output by the acoustic output device will be perceived as coming from the left or right, respectively.

As another example, the classified type of acceleration (which the vehicle - as well as the occupants - experience or are subjected to) can be used by the processing unit to cause a particular type of audible sound to be generated (or not or no longer to be generated) or the sound of a particular (musical) instrument or a processed version thereof to be generated (or not or no longer to be generated). Or, expressed in a different way, the classified type of sound (or instrument as part of the sound) may be made dependent on the classified type of acceleration.

This being by way of example only, it will be appreciated that other configurations will be possible.

In some embodiments, the detector is further configured to detect an upwards and/or a downwards movement of the vehicle and to provide a further detection output based thereon;.

These embodiments are based on the following recognition by the inventor: If a vehicle is going uphill or downhill - even if a vertical component of the velocity of the vehicle is not changing (over time), or even if the vehicle is travelling (uphill or downhill) in a straight line at a constant speed (i.e. in the absence of any acceleration of the vehicle, other than gravity) - a user may sense that the vehicle (and consequently the seat on which the user is sitting) is at a non-zero angle with respect to an orientation when the vehicle is travelling in a horizontal plane. This may contribute towards the user developing motion sickness. Hearing an audible sound as an indication of the uphill or downhill movement of the vehicle may help to reduce the effects of motion sickness.

At least some of the features described above in connection with acoustic output devices with surround sound function can - albeit in a more limited sense - also be implemented in acoustic output devices with a stereo function - both where these acoustic output devices form part of the vehicle or where they comprise, or form part of, a portable device. For example, a lateral acceleration can conveniently be audibly indicated to a user by outputting an audible sound via an acoustic output device respectively on the left or right-hand side of the user (e.g. left or right-hand speaker of headphones worn by the user, or left or right-hand loudspeaker of the vehicle).

In a second aspect, the present disclosure provides a vehicle for road use comprising the system according to the first aspect, or any embodiment thereof.

In a third aspect, the present disclosure provides a method of providing an indication of an acceleration of a vehicle for road use, the method comprising:.

In a fourth aspect, the present disclosure provides a computer program product comprising a program code which is stored on a computer readable medium, for carrying out the method in accordance with the third aspect, or any of its steps or combination of steps, or any embodiments thereof.

The computer program may in particular be stored on a non-volatile data carrier. Preferably, this is a data carrier in the form of an optical data carrier or a flash memory module. This may be advantageous if the computer program as such is to be traded independently of a processor platform on which the one or more programs are to be executed. In a different implementation, the computer program may be provided as a file or a group of files on one or more data processing units, in particular on a server, and can be downloaded via a data connection, for example the Internet, or a dedicated data connection, such as for example a proprietary or a local network. In addition, the computer program may comprise a plurality of interacting, individual program modules.

In some embodiments, the computer program may be updatable and configurable, in particular in a wireless manner, for example by a user or manufacturer. Likewise, the audible sound (to be generated) or the manner in which it is generated or modified, in particular the conditions which need to be fulfilled so that the audible sound will be generated or modified, may be updatable and configurable in some embodiments, in particular in a wireless manner, for example by a user or manufacturer.

The terms "first", "second", "third" and the like in the description and in the claims are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order.

Where the term "comprising" or "including" is used in the present description and claims, this does not exclude other elements or steps.

Further, unless expressly stated to the contrary, "or" refers to an inclusive "or" and not to an exclusive "or". For example, a condition "A or B" is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

All connections mentioned in the present specification may be wired or wireless unless this is explicitly excluded or technically impossible. The term "wired connection" encompasses not only connections established by, or using, a (metallic) wire, but also optical connections, preferably also any other type of physical connection allowing for the transmission of information.

Aspects and embodiments of the invention described or claimed herein can be combined with each other, and embodiments described in connection with one aspect of the invention can be combined with other aspects of the invention, unless such a combination is explicitly excluded or technically impossible.

Further advantages, features and applications of the present invention are provided in the following detailed description and the appended figures, wherein:.

<FIG> schematically shows a plan view of a vehicle <NUM> according to an embodiment of the present invention. The vehicle <NUM> is shown, by way of example, as a left-hand drive car, with two front seats <NUM>, <NUM>, two rear seats <NUM>, <NUM> and a steering wheel (not labelled). The front of the vehicle is at the top of <FIG>.

Vehicle <NUM> is equipped with a processing unit <NUM>. Processing unit <NUM> may comprise, or form part of, an onboard computer of vehicle <NUM>.

Processing unit <NUM> is connected to one or more loudspeakers <NUM> which are distributed at locations in the vehicle <NUM> and may be substantially permanently installed in vehicle <NUM>. In the example shown in <FIG>, there are six such loudspeakers <NUM>. Only one (wired) connection between processing unit <NUM> and one of the loudspeakers <NUM> (right-hand side, towards the front of the vehicle <NUM>) is shown. The other loudspeakers <NUM> may be connected in like manner. The connection(s) may be wired or wireless. More, or fewer, than six loudspeakers <NUM> may be provided. With only one loudspeaker <NUM>, only a mono effect may be achievable. With two loudspeakers <NUM>, a stereo effect may be achievable. For a surround sound effect, at least three loudspeakers <NUM> may be necessary, although it is preferred that vehicle <NUM> is equipped with (significantly) more than three loudspeakers. Loudspeakers <NUM> may all be positioned at the same height within the vehicle <NUM>, or at different heights, in which case a user may perceive the output from the loudspeakers <NUM> as coming not only from locations within one (horizontal) plane but also from locations above and/or below.

Processing unit <NUM> is also connected to one or more detectors <NUM> of a type that is able to detect a current, actual acceleration of vehicle <NUM>. Detector(s) <NUM> may, for example, comprise an accelerometer and/or a gyroscope.

Additionally, processing unit <NUM> is connected to one or more portable devices. <FIG> illustrates three such portable devices <NUM>, <NUM>, <NUM>. These will now be explained.

Portable device <NUM> is a personal portable device, such as a smartphone, laptop or tablet computer, headphones or a headset or similar, any of which may be connected to vehicle <NUM>, in particular to processing unit <NUM>, in a wired or wireless manner, for example via Bluetooth® or similar.

Portable device <NUM> is proprietary to vehicle <NUM>. It is held by, placed upon, or (removably) attached to a cradle or holder <NUM>, which may be (substantially permanently) installed in vehicle <NUM>, for example attached to the back of seat <NUM> or the headrest of seat <NUM>, and may form part of a rear seat entertainment (RSE) system. Cradle <NUM> is connected to processing unit <NUM> by a wired connection. Portable device <NUM> is also connected to cradle <NUM> by a wired connection. Portable device <NUM> may comprise a loudspeaker, headphones or a headset and may have a surround sound function. The location of cradle <NUM> with respect to the vehicle <NUM> may be known to processing unit <NUM>. A possible use of this information will be described later.

Portable device <NUM> and cradle/holder <NUM> may substantially correspond to portable device <NUM> and cradle/holder <NUM>, except that these are not connected by a wired connection to processing unit <NUM>, i.e. there is neither a wired connection between processing unit <NUM> and cradle <NUM>, nor between cradle <NUM> and portable device <NUM>. Portable device <NUM> may communicate with cradle <NUM>, or directly with processing unit <NUM>, in a wireless manner.

Cradle <NUM> may also communicate with processing unit <NUM> in a wireless manner, or may not communicate with processing unit <NUM> at all and may simply be a holder for (mechanically) accommodating portable device <NUM> and/or serve as a charging station for portable device <NUM>.

Variations of portable devices <NUM>, <NUM> and cradles/holders <NUM>, <NUM> are also possible, for example such that the portable device <NUM>, <NUM> is connected to a respective cradle <NUM>, <NUM> in a wireless manner whilst the respective cradle <NUM>, <NUM> is connected to processing unit <NUM> by a wired connection. Alternatively, portable device <NUM>, <NUM> may be connected to the respective cradle <NUM>, <NUM> by a wired connection whilst the respective cradle <NUM>, <NUM> is connected to processing unit <NUM> in a wireless manner.

Processing unit <NUM> may have one or more wireless interfaces <NUM> for communicating with any one, some or all of loudspeakers <NUM>, personal device <NUM>, portable devices <NUM>, <NUM> and/or detector <NUM>. Signals may be sent between processing unit <NUM> and portable devices <NUM>, <NUM>, <NUM> via their respective connections, if applicable via cradles <NUM>, <NUM>.

In addition or as an alternative, processing unit <NUM> may comprise a wired interface, for example an electrical connector for a cable-based connection with any, some or all of the other devices mentioned above. If these devices are hard-wired to processing unit <NUM>, then the interface may be regarded as a point along the connection between these devices and processing unit <NUM>. A wired connection can also be an indirect wired connection, for example such that cradles <NUM>, <NUM> are connected to processing unit <NUM> via a first wired connection (hard-wired or using a removable cable with one or more connectors), and portable devices <NUM>, <NUM> are connected to their respective cradle <NUM>, <NUM> via a second wired connection (hard-wired or using a removable cable with one or more connectors, for example plugged into an AUX socket of the respective cradle).

In some embodiments, not all of the devices are present or connected, or the system of certain embodiments of the invention may comprise only some of the devices illustrated in <FIG>. For example, embodiments are possible where the system comprises only the processing unit <NUM>, detector <NUM> and one audible output device such as a loudspeaker <NUM> or one of the portable devices <NUM>-<NUM>.

A method of operation of a system in accordance with the present invention will now be described with continued reference to <FIG> and further with reference to <FIG>.

<FIG> shows a flow chart illustrating a method according to an embodiment of the present invention.

After the start (<NUM>) of the method, the detector <NUM> detects (<NUM>) an actual (current) acceleration of the vehicle and provides (<NUM>) a detection output based thereon. The acceleration can be any one, or all, or any subset, of longitudinal acceleration, vertical acceleration, lateral acceleration, a right curve, a left curve, or road unevenness.

The detection output is then transmitted to processing unit <NUM>, where the detection output is processed (<NUM>) or analysed. In particular, processing unit <NUM> may include circuitry or program components to amplify the detection output, or to distinguish between detection outputs associated with the different types of acceleration, and to generate (<NUM>) a control signal based on the detection output. The control signal is thus indicative of the acceleration of the vehicle <NUM>.

One or more of the acoustic output devices <NUM>-<NUM> then receives the control signal and generates and outputs (<NUM>) an audible sound as a function of the control signal. The audible sound is thus indicative of the actual acceleration of the vehicle <NUM>. The user is thus given an audible indication of the current, actual acceleration of vehicle <NUM>, which may reduce the effects of motion sickness. Once the audible sound has been output, the method may end (<NUM>), or alternatively may be repeated.

As an (optional) additional step (not illustrated in <FIG>), the location of one or more of the output devices <NUM>-<NUM> with respect to vehicle <NUM> may be determined. In the case of loudspeakers <NUM>, their location would typically be fixed with respect to vehicle <NUM>, and their location may be known to processing unit <NUM> in advance, e.g. stored in a memory device of processing unit <NUM>, so that a determination of their location does not need to be carried out.

Various ways of generating the audible sound as a function of the control signal are possible. For example, the volume or frequency of the audible sound can be modulated with, or as a function of, the control signal. As one example, if the control signal is proportional to, or varies linearly with, the detected acceleration and if the audible sound is modulated as a function of the control signal in such a way that the volume of the audible sound is proportional to, or varies linearly with, the control signal, then the volume of the audible sound will also be proportional to, or will vary linearly with, the detected acceleration. As another example, the frequency of the audible sound could be modulated as a function of the control signal in such a way that the frequency of the audible sound varies linearly with the control signal and thus with the detected acceleration.

Of course, other relationships, in particular non-linear relationships, are possible between (a property of) the audible sound and the control signal/the detected acceleration. Likewise, depending on a measure of the acceleration, or the type of acceleration, different sounds may be added/removed, e.g. sounds of different (musical) instruments or processed versions thereof. Further, depending on a measure of the acceleration, or the type of acceleration, the processing unit <NUM> may cause the audible sound to be output from one or more particular acoustic output devices, e.g. such that the number of loudspeakers <NUM> from which the audible sound is to be output increases with increasing acceleration.

In some embodiments, the system can be configured such that an audible sound is generated whenever the vehicle <NUM> is operational, for example after a key or key card has been inserted into a corresponding receptacle or a start button has been pressed. Alternatively, the audible sound can be generated whenever the vehicle <NUM> is moving. In particular, the audible sound may resemble the sound of an internal combustion engine. The control signal can then be used by the system to modify a property of the audible sound.

One possibility of modifying a property of the audible sound is this: the audible sound may be composed of the sound of one or more musical instruments or processed versions thereof. When an acceleration has been detected, in particular above a fixed or (user) configurable threshold, the sound of a further musical instrument may be added to the audible sound. Similarly, the sound of a musical instrument may be omitted/removed from the audible signal, for example on detection of a deceleration.

The audible output devices <NUM>-<NUM> may also have a noise cancellation function. Similarly, vehicle <NUM> may have a noise cancellation function. In this case, outputting an audible sound indicative of the actual acceleration of vehicle <NUM> may be particularly useful in reducing the effects of motion sickness since vehicles or audible output devices with noise cancellation function - for example when a user is listening to music - tend to cause a user to be even less aware of surrounding noises such as an engine noise, which tends to contribute to motion sickness.

In some embodiments, the processing unit <NUM> can distinguish between different types of acceleration, such as longitudinal acceleration, vertical acceleration, lateral acceleration, a right curve, a left curve, or road unevenness. For example, the control signal may vary dependent on the type of acceleration detected. For example, in the case of a positive longitudinal acceleration, i.e. a positive acceleration in a forward direction, the control signal may be such that the audible sound is predominantly or exclusively output from acoustic output devices located towards the front of the vehicle <NUM>, whereas in the case of a negative longitudinal acceleration, i.e. a deceleration, the control signal may be such that the audible sound is predominantly or exclusively output from acoustic output devices located towards the rear of the vehicle <NUM>. Similarly, for left and right curves, the audible sound could predominantly or exclusively be output from acoustic output devices respectively located towards the left and right of vehicle <NUM>. In a case of road unevenness, the audible sound could be output by acoustic output devices in such a way that it is perceived, by a user, to come from a location towards the bottom of the vehicle <NUM>.

The different types of acceleration can also be distinguished in terms of the type of audible sound to be output, e.g. modulation in terms of volume/frequency for longitudinal acceleration and adding/removing a musical instrument for lateral acceleration etc..

The embodiment of the invention will now be described with continued reference to <FIG> and <FIG> and further with reference to <FIG>.

<FIG> schematically shows a top view of the head <NUM> of a person wearing headphones (or a headset), in a first orientation, and <FIG> schematically shows a top view of the head <NUM> of the person from <FIG>, in a second orientation. The reference number <NUM> is respectively placed towards the direction in which head <NUM> is facing. In other words, in the orientation of <FIG>, the head <NUM> is turned towards the top of the figure, whereas in <FIG>, the head <NUM> is turned towards the left.

<FIG> schematically show headphones worn by the person, whereby reference number <NUM> indicates a right-hand portion of the headphones and reference number <NUM> indicates a left-hand portion of the headphones. In the embodiment shown, the headphones <NUM>, <NUM> are headphones with surround sound function. The headphones are further equipped with one or more (built-in) devices <NUM> for determining the orientation/position of the headphones, in particular with respect to a local or global reference. Such devices <NUM> can, for example, comprise a gyroscope and/or an accelerometer, in particular a <NUM>-axis accelerometer, for example one gyroscope/accelerometer per headset or, as shown in <FIG>, one gyroscope/accelerometer <NUM> each for the right-hand portion <NUM> and the left-hand portion <NUM> of the headphones. Such devices <NUM> can, for example, (also) determine the orientation/position of the headphones with respect to a satellite-based signal, such as a GPS signal.

We now assume that the person (whose head <NUM> is shown in <FIG>) is sitting on the front right-hand seat <NUM> of vehicle <NUM>. The person shown in <FIG> is initially facing in the direction of travel of vehicle <NUM>, i.e. towards the front of vehicle <NUM>. We further assume that the system described above with reference to <FIG> is intended to generate and output an audible sound indicative of the actual acceleration of the vehicle <NUM>. Further, in this example, we assume that the person is supposed to perceive the audible sound as coming approximately from a central location at the front of vehicle <NUM>, where, at least in most conventional vehicles with an internal combustion engine, the engine would typically be located. This location is indicated as a square <NUM> in <FIG>. In accordance with this embodiment, the audible sound will be likely to provide the person with a particularly realistic impression of a sound coming from an internal combustion engine - even if vehicle <NUM> is an electric vehicle, for example.

In relation to the head <NUM> of the person, the location <NUM> may be considered to correspond to a direction of <NUM> o'clock (<NUM> o'clock being straight ahead). In order for the system to generate the audible sound in such a way that the person will perceive it as coming from the direction <NUM> o'clock, the system determines, using gyroscopes and/or accelerometers <NUM> or similar, the orientation and/or position of the headphones <NUM>, <NUM> in relation to vehicle <NUM>. On determining that the person is facing straight ahead, the system causes the headphones <NUM>, <NUM> to output the audible sound in such a way that the person will perceive the audible sound as coming (approximately) from the central location <NUM> at the front of vehicle <NUM>, i.e. the direction <NUM> o'clock with respect to the head <NUM> of the person. In <FIG>, this is indicated by a larger black circle <NUM> (indicating a higher volume) towards the front of the left-hand portion <NUM> of the headphones and a smaller black circle <NUM> (indicating a lower volume) towards the front of the right-hand portion <NUM> of the headphones.

Referring now to <FIG>, the person has turned their head <NUM> by <NUM>° towards the left. The central location <NUM> at the front of vehicle <NUM> now corresponds to <NUM> o'clock with respect to the head <NUM> of the person. Again using information (provided by gyroscopes and/or accelerometers <NUM> or similar) regarding the (changed) orientation/position of the headphones, the system can cause the headphones <NUM>, <NUM> to output the audible sound in such a way that the person will perceive the audible sound as coming (approximately) from the central location <NUM> at the front of vehicle <NUM>, i.e. the direction <NUM> o'clock with respect to the head <NUM> of the person. In <FIG>, this is indicated by a larger black circle <NUM> (indicating a higher volume) slightly towards the front of the right-hand portion <NUM> of the headphones and a very small black circle <NUM> (indicating a very low volume - lower than the volume <NUM> in <FIG>) slightly towards the front of the left-hand portion <NUM> of the headphones.

It will be appreciated that the technique illustrated with reference to <FIG> can be used with other locations/directions. However, it is preferred that the audible sound is perceived by the person as coming from a consistent direction with respect to vehicle <NUM>, regardless of the orientation/position of headphones <NUM>, <NUM>.

It is preferred that the audible sound is perceived by the person not only as coming from a consistent direction with respect to vehicle <NUM> but also as coming from an appropriate/consistent distance. We consider again the example of the audible sound imitating an engine noise coming from a central location <NUM> at the front of vehicle <NUM>. Further, in this example, we assume that a first user is sitting on (front) seat <NUM>, and a second user is sitting on (rear) seat <NUM>, behind seat <NUM>. An embodiment of the invention envisages that the first and second users not only perceive the audible sound as coming from slightly different directions, but also that the second user perceives the audible sound as coming from a location at a greater distance than is the case for the first user. Accordingly, assuming the (approximate) location of the acoustic output devices respectively used by the first and second users has been determined or is already known (to processing unit <NUM>), processing unit <NUM> can take this information into account to generate appropriate control signals respectively for the acoustic output devices used by the first and second users to ensure that the first user will perceive the audible sound as coming from a closer distance than the second user. It is envisaged that in most cases this will mean (inter alia) that the audible sound which the first user will perceive is at a greater volume than the audible sound that the second user will perceive.

Ensuring that the "correct" portion of headphones <NUM>, <NUM> is activated and at an appropriate volume so as to enable the person to perceive the audible sound as coming from a consistent direction can be implemented in at least two ways, which will be explained in the following.

In the first of these implementations, the gyroscopes and/or accelerometers <NUM> or similar provide information regarding the orientation/position of the headphones <NUM>, <NUM> to the processing unit <NUM>. The processing unit <NUM> then generates the control signal taking into account this information, i.e. the control signal then includes information as to which portion of headphones <NUM>, <NUM> to activate and at what volume (based on the distance between headphones <NUM>, <NUM> and the consistent location <NUM>). The headphones <NUM>, <NUM> can then use the received control signal to output the audible sound <NUM>, <NUM>. The headphones <NUM>, <NUM> then do not need to calculate themselves which portion of headphones <NUM>, <NUM> to activate and at what volume (taking into account the direction from which the audible sound is supposed to be perceived as coming from, as well as the orientation/position of the headphones <NUM>, <NUM>, and in particular the distance between headphones <NUM>, <NUM> and the consistent location <NUM>) - since the control signal received from processing unit <NUM> already contains this information.

In the second of these implementations, the gyroscopes and/or accelerometers <NUM> or similar again provide information regarding the orientation/position of the headphones <NUM>, <NUM>. However, this information is not transmitted to the processing unit <NUM> so that the processing unit then generates the control signal without being aware of the orientation/position of headphones <NUM>, <NUM>. The control signal will therefore also not include information as to which portion of headphones <NUM>, <NUM> to activate and at what volume but instead informs the headphones <NUM>, <NUM> of the position (with respect to vehicle <NUM>) from which the audible sound is supposed to be perceived as coming from. The headphones <NUM>, <NUM> can then use the received control signal and the information provided by its own gyroscope(s) and/or accelerometer(s) <NUM> or similar to calculate which portion of headphones <NUM>, <NUM> to activate and at what volume so that the person will perceive the audible sound as coming from the "correct"/consistent direction with respect to vehicle <NUM> and "correct"/consistent distance.

Techniques for determining the location of an acoustic output device such as headphones <NUM>, <NUM> with respect to a reference, such as vehicle <NUM> or a particular reference location within the vehicle <NUM>, are known per se. For example, if an acoustic output device such as headphones <NUM>, <NUM> are connected to processing unit <NUM> or a cradle <NUM>, <NUM> or some other reference point of vehicle <NUM> via Bluetooth® or similar, signal parameters such as the angle of arrival, potentially detected at multiple, spaced apart locations, can be used to determine the relative location of the acoustic output device.

In a variant, the orientation/position of the headphones <NUM>, <NUM> is detected by one or more cameras or other sensors, such as camera <NUM> shown in <FIG>, and the corresponding information is then provided to processing unit <NUM> and/or the headphones <NUM>, <NUM>. Camera <NUM> may be substantially permanently installed in vehicle <NUM>. The position of camera <NUM> in <FIG> is indicative only; other locations are possible.

In a further development of any of the embodiments described above, the system also detects whether the vehicle <NUM> is travelling uphill or downhill, for example using detector (gyroscope/accelerometer) <NUM>, and/or using a global reference such as a signal from a satellite-based positioning system. Even in the absence of any acceleration (other than gravity), a (further) control signal indicative of the uphill or downhill movement can then be generated and a corresponding audible sound can be output based thereon, in accordance with what has been described above in connection with detected acceleration of vehicle <NUM>.

Claim 1:
A system (<NUM>, <NUM>-<NUM>, <NUM>) for providing an indication of an acceleration of a vehicle (<NUM>) for road use, the system (<NUM>, <NUM>-<NUM>, <NUM>) comprising:
a detector (<NUM>) configured to detect an actual acceleration of the vehicle (<NUM>) and to provide a detection output based thereon;
a processing unit (<NUM>) configured to receive the detection output, the processing unit (<NUM>) further being configured to generate a control signal based thereon; and
an acoustic output device (<NUM>-<NUM>) configured to receive the control signal and to generate and output an audible sound (<NUM>, <NUM>) as a function of the control signal, the audible sound (<NUM>, <NUM>) being indicative of the actual acceleration of the vehicle (<NUM>),
wherein the acoustic output device (<NUM>-<NUM>) comprises, or forms part of, a portable device (<NUM>-<NUM>), and wherein the processing unit (<NUM>) is arranged to cause the acoustic output device (<NUM>-<NUM>) to output the audible sound (<NUM>, <NUM>) in such a way that a user of the acoustic output device (<NUM>-<NUM>) perceives the audible sound (<NUM>, <NUM>) as coming from a substantially consistent direction (<NUM>) and/or location (<NUM>) relative to the vehicle (<NUM>), irrespective of the location and/or orientation of the acoustic output device (<NUM>-<NUM>) relative to the vehicle (<NUM>).