NL2002184C2

NL2002184C2 - Tactile speed control assist for car drivers.

Info

Publication number: NL2002184C2
Application number: NL2002184A
Authority: NL
Inventors: Herman Verhey Wijk
Original assignee: Verhey Van Wijk Beheer B V
Priority date: 2008-11-07
Filing date: 2008-11-07
Publication date: 2010-05-10
Also published as: WO2010052236A1

Description

TACTILE SPEED CONTROL ASSIST FOR CAR DRIVERS FIELD OF THE INVENTION

The invention relates to a motor vehicle for use on a public road and comprising a user-5 feedback system for signaling to the vehicle’s operator that a pre-determined road speed has been attained. The invention also relates to such a system.

BACKGROUND ART

Modern motor vehicles designed for use on the public road, such as automobiles, trucks 10 and motorcycles, are typically equipped with systems, electronically controlled by an onboard computer, that assist the driver or rider with safely operating the vehicle without unnecessary distraction. Examples of such systems are anti-lock brakes, traction control systems, navigation aids, engine management systems, cruise control systems, etc.

Cruise control allows the vehicle to maintain a pre-set speed by means of automatically 15 regulating (i.e., without the driver’s intervention) the throttle depending on the actual road speed deviating from the pre-set speed.

Some drivers use cruise control to avoid violating legal speed limits. This type of use is feasible only on a long stretch of a highway, e.g., the German Autobahn, at times when there is hardly any traffic. In densely populated areas or in heavy traffic, cruise control is practically not 20 useable as the vehicle’s operator needs to adjust the road speed continually in order to adapt to changing circumstances such as traffic jams, traffic lights, merging traffic, changes in local legal speed limits, etc.

Law enforcement officers and road operators are increasingly more alert on catching drivers who violate the local speed limit, even those who exceed the speed limit by only a small 25 amount. The rationale for this is to force drivers to obey the traffic rules and to reduce the probability of a speed-related accident. Higher speeds leave less time for the driver to respond to changing circumstances, thus increasing the chance of getting involved in an accident. Also note that too low a speed can be dangerous as well, e.g., when a vehicle driving with a low speed is not expected by other drivers, or when overtaking traffic on a road with opposing lanes 30 and without a center divider. Many drivers may know very well how to operate a car but somehow fail to develop any road sense, preventing them from effectively being able to anticipate likely changes in the traffic ahead or in road conditions due to inclement weather. Many drivers also believe that some speed limits in some places are ridiculously low, not realizing that a lower speed may optimize traffic flow, and these people can only be forced to 2 obey by means of tight speed checks carried out by law enforcement officers or automated detection systems, and heavy fines.

However, exceeding the local speed limit by only a small fraction does not always result in a disproportionate increase in danger. Violating the local speed limit only slightly for a short 5 time may even help to resolve an otherwise hazardous situation, e.g., when using the lane for traffic in the other direction when overtaking a heavy truck in one’s own lane. This violation, however, will nevertheless be registered by an automated speed checking appliance such as a road safety camera, as a result of which the speeding driver will receive a speeding ticket in due time. A feeling of grave injustice will probably emerge, but the only thing one can do is to let the 10 case be taken to court and to explain one’s case to the judge. This usually does not merit the driver’s investment in time and effort.

In order to support the driver nevertheless with not exceeding the legal speed limit, some cars enable the driver to pre-program one or more pre-determined speeds into the onboard computer. The user-programmed speeds are, for example, representative of frequently occurring 15 legal speed limits. Upon reaching a pre-programmed speed, the computer generates a signal that is made visible or audible to the driver through a suitable user interface such as a flashing dashboard light or a beeping sound. In this manner, the driver is audibly or visually alerted to the speed at which he/she is driving, thus providing a feedback mechanism without the driver needing to constantly keep an eye on the speedometer. Also, some personal navigation 20 devices, e.g., a range of products manufactured by TomTom, have a feature that shows icons on the device’s display monitor with the speed limits of the roads on which one is traveling.

When the local speed limit is exceeded by a certain amount, the icon turns red and starts flashing to attract the driver’s attention.

25 SUMMARY OF THE INVENTION

The inventor has realized that an audible or visible signal for alerting the driver to the current road speed is less then optimal, when the driver’s visual and auditory senses are already fully occupied, if not overloaded, with operating the vehicle and navigating the traffic. In addition, the visual signal in the form of a flashing light has to compete with other visual information that 30 the driver has to process, e.g., the constantly changing traffic situations or visual directions of the onboard navigation system, the dashboard lights of the turn indicators or of low fuel level, etc. The audible signal has to compete with the sounds of the engine, of the tires on the road surface, of nearby traffic, from the navigational guidance given via the vehicle’s loudspeaker, from the car radio or music player, from passengers, wind noise, etc. Accordingly, an audible or 3 visual speed-related signal may be distracting, confusing or may even not be noticed in time at all by the driver.

The inventor therefore proposes to use a speed-related warning signal of another modality and, moreover, to have it synergistically combined with the conventional user controls 5 of the motor vehicle.

Therefore, an embodiment of the invention relates to a motor vehicle, e.g., an automobile, a motorcycle, or a truck, for use on a public road. The vehicle comprises a user-feedback system for providing feedback to the user about the current road speed. The system comprises a controller for generating a control signal in dependence on a difference between a 10 magnitude of an actual road speed of the vehicle and a pre-determined magnitude of the road speed. The system further includes an actuator functionally coupled to the controller for, in response to the control signal, introducing a tactile signal in an accelerator device, such as the throttle pedal (“accelerator”) of a car or truck or the twist grip throttle on the handlebar of a motorcycle. Such an accelerator device is part of the conventional user interface of a motor 15 vehicle for user control of the actual road speed of the vehicle.

The functional coupling between the controller and the actuator sees to it that the actuator receives the control signal. This functional coupling can be implemented in a wired manner or in a wireless manner, well within the capabilities of the skilled person.

The tactile feedback according to the invention uses a sensory channel of the driver 20 different from the visual and auditory channels, thus avoiding a sensory overload of the latter. Also, the tactile signal is not going to be obscured or drowned by other tactile perceptions relevant for operating the vehicle, if any. In addition, the functional integration of the actuator with the accelerator device stimulates the driver exactly at that part of the body that actively controls the vehicle’s road speed.

25 In a further embodiment of the invention, the controller is functionally integrated with an onboard computer of the vehicle. The functionality is then implemented by computer code that may be loaded into the onboard computer at the assembly plant of the vehicle, at the importer or at the local dealer, or even by the vehicle’s owner via a data network such as the Internet as part of an after-market add-on.

30 In a further embodiment, the controller is integrated with a personal navigation device.

For example, a range of such products manufactured by TomTom comprises a feature of detecting the deviation of the actual road speed from a local speed limit, and of generating a signal accordingly that controls the rendering of an icon in the visual user interface of the navigation device. The known device can be modified by the skilled person to have this signal 4 made available electrically, electromagnetically or optically at an output port of the device. In operational use of the personal navigation device, the output port is then functionally coupled to the actuator, e.g., wirelessly, wired via the vehicle’s onboard electrical system or via an optical fiber, etc., and via a transcoder or transducer if signal conversion to a suitable format is needed.

5 Preferably, the dependence between the control signal for the actuator and the road speed is programmable (e.g., user-programmable) or re-programmable with respect to, e.g., one or more pre-determined magnitudes of the road speed for which the tactile signal is to be introduced and/or an attribute of the tactile signal. With regard to the feature “attribute of the tactile signal”, this may include, for example, one or more of: an intensity of the tactile signal, a 10 frequency of a vibratory tactile signal, a change in resistance against moving the accelerator device, a temporal aspect of the tactile signal such as duration, a modality of a change in frequency and/or intensity dependent on a change in the road speed, etc. The attribute may have a value that depends on the difference according to a pre-determined profile. In an embodiment, the profile is such that the value increases if the difference increases in a first part 15 of the pre-determined profile wherein the difference is larger than zero. In a further embodiment, the profile is such that the value increases if the difference decreases in a second part of the pre-determined profile wherein the difference is smaller than zero; and an absolute magnitude of a rate of change of the value (per unit of speed) in the first part is larger than the absolute magnitude of the rate of change of the value (per unit of speed) in the second part. In a further 20 embodiment, the controller is operative to control the actuator according to a profile so that the tactile signal is absent in a range of values of the difference around a zero difference. The range represents magnitudes of the actual road speed differing from the pre-determined magnitude of the road speed by a relatively small fraction of the pre-determined road speed.

For example, the controller is programmed to have the actuator generate a tactile signal 25 around the following values of the road speed: 50 km/h, 70 km/h and 100 km/h. The controller is programmed to have the actuator generate tactile signals that increase in intensity and/or frequency upon the actual road speed approaching one of the pre-programmed road speeds, and that are more or less stationary or absent in a practically narrow range around the preprogrammed road speed. Upon a slight change of the throttle position while driving at a speed 30 within this narrow range, the user senses the tactile signal and can readjust accordingly. The attributes of the tactile signal generated at approaching the pre-determined speed while accelerating is, for example, programmed to be different from the attributes of the tactile signal generated at approaching the pre-determined speed while decelerating. For example, the tactile signal may introduce a slight increase in resistance of the accelerator device against moving as 5 perceived by the driver operating the accelerator device while accelerating, whereas the tactile signal may introduce a slight decrease in resistance while decelerating. The controller may be programmed to not generate a control signal if the magnitude of the vehicle’s actual acceleration or the magnitude of the vehicle’s actual deceleration is higher than a pre-determined threshold.

5 When the acceleration or the deceleration is higher than the pre-determined threshold, then this is interpreted as that the driver is intentionally accelerating or decelerating. Similarly, the controller may be programmed to not generate the control signal when the engine speed (in terms of revolutions per second) is higher than a certain pre-determined threshold, and/or changes at a rate higher than a further pre-determined threshold, thus indicating that the 10 acceleration is intentional. Moreover, different profiles or attributes for different ones of multiple pre-determined speeds may be programmed into the controller.

In a further embodiment, the actuator is physically integrated with the accelerator, e.g., physically embedded in the accelerator pedal or throttle grip, integrated with the mechanical linkage of the pedal or throttle grip to the engine, or integrated with the mechanical support of 15 the pedal or grip.

Increasingly more road vehicles are designed with a drive-by-wire configuration, wherein the coupling between the accelerator pedal, on the one hand, and the engine on the other hand, is implemented electronically instead of purely mechanical using cables and/or rod linkages.

This implies that the electronic infrastructure is already available in the vehicle, to which the 20 functionality of the invention can be added relatively simply, e.g., by means of loading proper software and adding an actuator to the accelerator device.

The invention may therefore commercially also be exploited as a user-feedback system for use in a motor vehicle that is designed for use on a public road. The system comprises a controller for generating a control signal in dependence on a pre-determined magnitude of a 25 road speed of the vehicle, and an actuator for being functionally coupled to the controller and configured for, in response to the control signal, introducing a tactile signal in an accelerator device in a user interface of the vehicle for user control of the actual road speed. Such a system can be provided as an accessory built into the new vehicle at the factory, or as an after-market add-on feature.

30 Preferably, the dependence is programmable or re-programmable with respect to at least one of following: one or more magnitudes of the road speed for which the tactile signal is to be introduced; and an attribute of the tactile signal. In a further embodiment, the actuator is physically integrated with the accelerator device.

6

The following embodiments are considered advantageous, wherein the reference numerals refer to the accompanying drawing: 1. A motor vehicle (100) for use on a public road and comprising a user-feedback system (102) that includes: 5 a controller (104) for generating a control signal in dependence on a difference between a magnitude of an actual road speed of the motor vehicle and a pre-determined magnitude (208) of the road speed; and an actuator (108) functionally coupled to the controller for, in response to the control signal, introducing a tactile signal in an accelerator device (110) in a user interface of the 10 vehicle for user control of the actual road speed of the motor vehicle.

2. The motor vehicle of embodiment 1, wherein the controller is functionally integrated with an onboard computer of the motor vehicle.

3. The motor vehicle of embodiment 1, wherein the dependence is programmable or reprogrammable with respect to at least one of following: 15 one or more predetermined magnitudes of the road speed for which the tactile signal is to be introduced; and an attribute of the tactile signal.

4. The motor vehicle of embodiment 3, wherein the attribute has a value that depends on the difference according to a pre-determined profile (200; 300).

20 5. The motor vehicle of embodiment 4, wherein the value increases if the difference increases in a first part of the pre-determined profile wherein the difference is larger than zero.

6. The motor vehicle of embodiment 5, wherein: the value increases if the difference decreases in a second part of the pre-determined profile wherein the difference is smaller than zero; and 25 an absolute magnitude of a rate of change of the value in the first part is larger than the absolute magnitude of the rate of change of the value in the second part.

7. The motor vehicle of embodiment 3, wherein the one or more predetermined magnitudes of the road speed are programmable or reprogrammable into the controller via at least one of: 30 a configuration user interface (112) of the user-feedback system; a wireless connection to a source (402) external to the motor vehicle; and a personal navigation device (502) storing information on speed limits in a road network.

8. The motor vehicle of embodiment 1, wherein: 7 the controller is operative to control the actuator so that the tactile signal is absent in a range (210) of values of the difference around a zero difference; and the range represents magnitudes of the actual road speed differing from the predetermined magnitude of the road speed by a relatively small fraction of the pre-determined road 5 speed.

9. The vehicle of embodiment 1, wherein the actuator is physically integrated with the accelerator device.

10. A user-feedback system (102) for use in a motor vehicle (100) that is designed for use on a public road, the system comprising: 10 a controller (104) for generating a control signal in dependence on a difference between a magnitude of an actual road speed of the motor vehicle and a pre-determined magnitude (208) of the road speed; and an actuator (108) functionally coupled to the controller for, in response to the control signal, introducing a tactile signal in an accelerator device (110) in a user interface of the 15 vehicle for user control of the actual road speed of the motor vehicle.

11. The system of embodiment 10, wherein the dependence is programmable or reprogrammable with respect to at least one of following: one or more predetermined magnitudes of the road speed for which the tactile signal is to be introduced; and 20 an attribute (202) of the tactile signal.

12. The system of embodiment 11, wherein the attribute has a value that depends on the difference according to a pre-determined profile (200; 300).

13. The system of embodiment 12, wherein the value increases if the difference increases in a first part of the pre-determined profile wherein the difference is larger than zero.

25 14. The system of embodiment 13, wherein: the value increases if the difference decreases in a second part of the pre-determined profile wherein the difference is smaller than zero; and an absolute magnitude of a rate of change of the value in the first part is larger than the absolute magnitude of the rate of change of the value in the second part.

30 15. The system of embodiment 11, wherein the one or more predetermined magnitudes of the road speed are programmable or reprogrammable into the controller via at least one of: a configuration user interface (112) of the user-feedback system; a wireless connection to a source (402) external to the motor vehicle; and a personal navigation device (502) storing information on speed limits in a road network.

8 16. The system of embodiment 10, wherein: the controller is operative to control the actuator so that the tactile signal is absent in a range (210) of values of the difference around a zero difference; and the range represents magnitudes of the actual road speed differing from the pre-5 determined magnitude of the road speed by a relatively small fraction of the pre-determined road speed.

17. The system of embodiment 10, wherein the actuator is physically integrated with the accelerator device.

For completeness, reference is made to following publications: 10 US 20040254048 discloses an apparatus for generating tactile force for a vehicle including a motor for generating the tactile force, a spring for generating the tactile force, an electromagnetic brake for cooperatively generating the tactile force with at least one of the motor and the spring, an accelerator pedal and a shift lever. The apparatus generates the tactile force for at least one of the accelerator pedal and the shift lever with a drive-by-wire method. The 15 apparatus comprises a detector for detecting an amount of depression of the accelerator pedal; a throttle control unit for controlling a throttle angle according to a signal indicative of the amount of depression detected by the detector; and a pedal tactile force generator for providing the accelerator pedal with the tactile force according to the signal.

US patent 5,794,730 discloses a transportation vehicle that is used as a prosthetic device 20 that permits locomotion of an otherwise impaired person. The vehicle appears to be a motorized wheel-chair or wheeled platform with stair-climbing legs for moving the impaired person over ground that may be irregular. The contraption is controlled via a manual user interface such as a joystick. An indication system is provided which modulates the pitch and repetition rate of an audible or tactile signal in accordance with speed and orientation of the vehicle.

25 US 20070106475 discloses a vehicle driving assist system that is configured to convey a risk potential relating to a preceding obstacle to a driver using both visual information and haptic information. For example, the vehicle driving assist system executes accelerator pedal actuation reaction force control such that an actuation reaction force is generated in accordance with a risk potential that expresses a degree of convergence between the host vehicle and a preceding 30 obstacle. In order to convey to the driver in a clear manner which preceding obstacle(s) is an obstacle targeted by the risk potential calculation and the reaction force control, the system displays a reference frame or marker at a position corresponding to the targeted obstacle (preceding vehicle).

9 US 20030130091 discloses a method and device for issuing a feedback signal to the driver of a motor vehicle as soon as an admissible constant load limit of a shifting element in a motor vehicle transmission, especially a starting clutch in an automatic transmission, is exceeded. The feedback signal to the driver takes the form of a haptic signal via an accelerator 5 pedal of the motor vehicle as pulsated motion of the throttle pedal.

Above publications demonstrate that actuators, for providing a tactile feedback to an operator of a vehicle, are known and that providing tactile feedback to the driver of a motor vehicle via the accelerator pedal, is known as well to the skilled person. Such actuators are also known from, e.g., mobile telephones that provide vibro-tactile sensations such as the E770 10 handset from Samsung upon receiving a call or an SMS message. The force-feedback technology used has been developed by Immersion Corporation. Accordingly, the basic implementing technologies used in the invention are known to the person skilled in the art. However, none of above publications either teaches or suggests the specific functionality as proposed by the inventor.

15

BRIEF DESCRIPTION OF THE DRAWING

The invention is explained in further detail, by way of example and with reference to the accompanying drawing, wherein:

Fig.1 is a block diagram of a vehicle in the invention; 20 Figs.2 and 3 are diagrams of profiles of an attribute of the tactile feedback signal in the invention; and

Figs. 4 and 5 are block diagrams with variations on the theme of Fig.1.

Throughout the drawing, same reference numerals indicate similar or corresponding features.

25

DETAILED EMBODIMENTS

Fig.1 is a block diagram of a motor vehicle 100 in the invention. Vehicle 100 is designed for use on the public road, e.g., a passenger car, a truck, a motorcycle, etc. Vehicle 100 comprises a user-feedback system 102 for signaling to the vehicle’s driver that a pre-determined 30 road speed has been attained. System 102 has a controller 104 that is configured for generating a control signal in dependence on a pre-determined magnitude of the road speed of the vehicle. To this end, controller 104 receives an input representative of the vehicle’s current road speed from a speed detector 106, e.g., a speedometer in vehicle 100 via a suitable interface (not shown). The interface may need to transcode the signal from speed detector 106 to a format 10 suitable for being processed by controller 104, e.g., an analog-to-digital converter. Alternatively, a GPS receiver (not shown) can be used as speed detector 106 in order to determine the current road speed and to generate a representative signal for controller 104. Within this context, reference is also made to personal navigation devices, such as products manufactured 5 by TomTom, that are configured to determine the vehicle’s current road speed, as mentioned above. Again, a suitable transcoding interface can be used, if needed. Controller 104 comprises, e.g., a data processor or a microcontroller. Alternatively, controller 104 is an integral part of the vehicle's onboard computer system (not shown separately) that takes care of, e.g., motor management tasks and that provides a user interface to the user-controllable functions of 10 vehicle 100. Controller 104 comprises computer code (not shown) with instructions as to how to process the signals input to controller 104. System 102 also comprises an actuator 108 that is under control of controller 104. In response to a control signal from controller 104, actuator 108 generates a tactile signal in an accelerator device 110 of vehicle 100. Accelerator device 110 is, e.g., an accelerator pedal if vehicle 100 is a dual track vehicle such as a car or a truck, and a 15 throttle grip in case vehicle 100 is a single-track vehicle such as a scooter or a motorcycle. The driver of vehicle 100 controls the road speed of vehicle 100 through pedal 110 or throttle 110 (in combination with the brakes (not shown) and the gearbox (not shown) of vehicle 100. Typically, the driver’s foot (in case of an automobile) or the rider’s hand (in case of a motorcycle) is continually in physical contact with accelerator 110 in operational user of vehicle 100.

20 Accordingly, the tactile signals generated by actuator 110 are sensed by the driver being in contact with vehicle 100 through accelerator 110.

Controller 104 is programmed to control actuator 108 depending on a difference between a magnitude of the current road speed of vehicle 100 and a pre-determined magnitude of the road speed. The resulting tactile signal alerts the driver to the fact that this pre-determined 25 road speed has been attained. This alerting can be used to keep the driver from speeding if the pre-determined road speed equals, or is slightly lower than, the local speed limit. Controller 104 may trigger actuator 108 at more than one magnitude of the road speed, e.g., at those magnitudes of the road speed that correspond to frequently occurring legal speed limits such as 50 km/h, 60 km/h, 70 km/h, 80 km/h, 100 km/h and 120 km/h in many European countries. Such 30 pre-determined magnitudes can be pre-programmed into controller 104 off factory. Alternatively, the driver or owner of vehicle 100 can pre-program these magnitudes him/herself into controller 104 through a suitable configuration user-interface 112. If controller 104 forms an integral part of the onboard computer system of vehicle 100, configuration user interface may form an integral part of the user interface to the onboard computer system. If controller 104 is a separate entity, π controller 104 may have its own configuration user interface 112 accommodated in a common housing and providing, e.g., a hierarchical menu of options for the driver to select in order to configure operation of controller 104. Alternatively, controller 104 has a port, e.g., a USB port, to enable configuring controller 104 via a personal computer (PC).

5 If a personal navigation device, e.g., as made by TomTom, is being used that measures the current road speed and visually signals to the driver when a local speed limit is being exceeded, the pre-determined magnitudes of the road speeds have not been programmed by the user. Instead, these pre-determined magnitudes have been pre-programmed into the navigation device. Accordingly, if the navigation device is being used as an integral part of the 10 system in the invention, the pre-determined magnitudes of the road speed, at which the system generates a tactile feedback to the driver, change dynamically.

Yet another scenario is feasible, wherein road operators, road authorities, local governments, or law enforcement departments use a roadside beacon for wirelessly transmitting a signal that represents the local speed limit, or the end of a local speed limit. In an embodiment 15 of the invention, controller 104 is equipped with a receiver for receiving this signal, for thereupon configuring or re-configuring the functionality of the invention by determining the pre-determined magnitude of the road speed as associated with the speed limit of the signal received from the beacon. Of course, this scenario can be used, mutatis mutandis, with a visual or auditory feedback signal to the driver.

20 Actuator 110 may be implemented using, e.g., the force-feedback technology developed by Immersion Corporation, as used by certain mobile phones, or any other electromechanical device of a suitable form-factor that can generate vibrations or forces strong enough to be felt via accelerator 110. It is known to the person skilled in the art of providing tactile feedback to a user interface for control of a vehicle how to implement the invention using known technologies. 25 Fig.2 is a diagram illustrating a profile 200 of the magnitude of an attribute 202 of the tactile feedback signal, provided by actuator 108 under control of controller 104, as a function of a magnitude of road speed 204 of vehicle 100. Attribute 202 represents, e.g., the frequency of the feedback signal (vibrations) generated by actuator 108, or the intensity or magnitude of the feedback signal. Attribute 202 has zero value outside a certain range of speeds 206 comprising 30 a pre-determined road speed 208 as programmed into controller 104. That is, there is no tactile feedback outside range 206. The width of range 206 is chosen such that the driver, accelerating to speed 208, notices the feedback signal when the actual road speed is slightly below speed 208. The intensity and/or frequency of the feedback signal increases upon the actual road speed approaching speed 208. Speed 208 lies in a smaller range 210 wherein the value of attribute 12 202 is practically zero, so that tactile feedback is practically absent. If the driver maintains a road speed that falls within range 210, he/she substantially drives at speed 208 and does not substantially violate the speed limit of speed 208. If, however, the driver then lets vehicle accelerate unintentionally, there is a steep increase in the value of attribute 202, e.g., the 5 magnitude of the frequency and/or intensity of the feedback signal, thus alerting the driver to the speed increase. The driver will then intuitively lift his/her foot or slightly close the throttle grip, or even slightly touch the brakes, in order to restore the desired speed to be within range 210 around speed 208. Also, if vehicle 100 has a road speed substantially equal to pre-determined road speed 208, and if the driver unintentionally releases accelerator device 110, the vehicle’s 10 road speed slightly drops below pre-determined speed 208. According to profile 200, tactile feedback is generated again in order to alert the driver to the decrease in road speed.

Preferably, the tactile feedback signal at speeds lower than speed 208 is of a gentler character, e.g., lower in magnitude and with a gentler rate of change, than the tactile feedback signal at speeds higher than speed 208, as indicated by the gentler slope and lower peak of profile 200 at 15 the left side of speed 208, and by the steeper slope and higher peak of profile 200 at the right side of speed 208.

Fig.3 is a diagram of another profile 300 of the magnitude of the attribute 202. Now, only that part of profile 200 is maintained that alerts the driver if the actual road speed exceeds predetermined speed 208. Note that in interval 210 there is again no tactile feed-back signal as the 20 value of attribute 202 is zero.

The widths of ranges 206 and 210, and the locations of the peaks in profiles 200 and 300 are chosen based on, e.g., the allowance made by law enforcement authorities for inaccuracies in speed detectors and other margins, the response time of a typical driver upon sensing the tactile feedback, etc. Profiles that are similar to profiles 200 and 300 can be applied to the tactile 25 feedback signals generated at other pre-programmed road speeds. The profiles at the other predetermined road speeds can optionally be scaled, e.g., stretched or compressed horizontally along the axis of road speed 204 in order to take into account wider detection margins at higher road speeds, and or stretched or compressed vertically along the axis of magnitude 202 in order to take into account the fact that driving vehicle 100 at higher speeds may generate more 30 vibrations than at lower speeds. As a result, increasing the peak values and/or slopes of the profiles for higher road speeds improves the signal-to-noise ratio.

Other profiles than the ones of Figs.2 and 3 are feasible and can preferably be programmed by the user via configuration user interface 112 through suitable editing software on or for controller 104.

13

Preferably, controller 104 keeps actuator 108 inactive when it is clear that the driver of vehicle 100 is intentionally accelerating. This can be determined on the basis of the magnitude of the acceleration, i.e., the rate of change of the road speed of vehicle 100, and/or on the basis of the engine speed in terms of revolutions per second.

5 Preferably, system 102 can be turned on or turned off by the driver or owner of vehicle 100 at will.

Configuration interface 112 in above examples can be implemented using, e.g., a graphical user interface (GUI) with dedicated buttons and/or dials, or with a touch-screen GUI. Alternatively, interface 112 can be implemented using voice control, which is itself a known 10 technology. Especially in view of the limited number of information items needed to configure operation of controller 104 (e.g., the indication(s) of the pre-determined road speed(s) for programming, lower or higher magnitude of the attribute of the tactile feedback signal), voice control may provide a suitable, hands-free user interface for configuring operation.

Fig.4 is a block diagram of motor vehicle 100 in the invention, wherein controller 104 15 wirelessly receives from a source 402 external to vehicle 100, via an antenna 404 and a suitable interface (not shown) data representative of the predetermined magnitude of the road speed to be used as the reference for generating the control signal for actuator 108, as explained above. In the example shown, source 402 comprises a short-range beacon operated by, e.g., the local road operator or law enforcement department. Alternatively, controller 104 comprises a wireless 20 receiver (not shown), e.g., a General Packet Radio Service (GPRS) receiver. As known, GPRS is a packet-oriented Mobile Data Service available to users of GSM mobile telephones. The expression “packet oriented” refers to the way data packets are multiplexed. Alternatively, the wireless receiver comprises a Radio Data System (RDS) receiver. The RDS technology uses conventional FM radio broadcasts to send data. RDS technology is typically used to implement a 25 Traffic Message Channel (TMC) for delivering traffic information to drivers. Other implementations of the wireless receiver are based on, e.g., Digital Audio Broadcasting (DAB) technology, or satellite radio, the latter using a communications satellite that covers a larger geographical area than do transmissions using a terrestrial technology. If the data representative of local predetermined speed limits is received via GPRS, RDS or DAB broadcasts, the data 30 needs to be filtered so as to select the relevant one of the speed limits. If each individual data item representative of an individual speed limit is accompanied by an identification of the relevant road or other geographic information, the filtering can be done on the basis of the actual geographic location of vehicle 100 determined by a navigational aid (not shown) such as a GPS device.

14

Fig.5 is a block diagram of motor vehicle 100 in the invention, wherein controller 104 receives from a personal navigation device 502 of the user of vehicle 100, via a suitable interface 504, data representative of the difference between actual road speed of vehicle 100 and the predetermined magnitude of the local speed limit. As mentioned above, personal 5 navigation devices currently being marketed by, for example, TomTom, are configured to determine the actual road speed using a GPS technology. The navigation devices have stored onboard maps of a road network and information about the speed limits of individual roads, which can be dynamically updated through GPRS. Such devices are configured to visually alert the driver to his/her speeding by means of flashing icons on the display monitor of the navigation 10 device. This implies that navigation device itself is capable of determining the difference between actual road speed and a local speed limit and of generating a signal for control of the flashing icons. The invention in the embodiment of Fig.5 now uses this signal internal to navigation device 502 as an input to controller 104, possibly via a suitable interface or transcoder 504. Navigation device 502 must further have a port for supply of this signal to a 15 destination outside of device 502. Navigation device 502 may also be configured to supply a further signal to controller 104 that is representative of the actual road speed. Accordingly, on the basis of the signal, representative of the difference between actual road speed and speed limit, and the further signal representative of the actual road speed, controller 104 is capable of generating the proper control signal for actuator 108 so as to control the generation of a tactile 20 feedback signal with a profiled attribute as shown in Figs.2 and 3.

As is clear to the skilled person, features appearing in different ones of the appended claims can be combined in specific embodiments of the invention that are not explicitly discussed above.

Claims

A motor vehicle (100) for use on public roads, the motor vehicle comprising a system (102) for feedback to a user, and wherein the system comprises: a control unit (104) for generating a control signal in dependence on a difference between a magnitude of a current speed of the motor vehicle and a predetermined magnitude (208) of the speed; and an actuator (108) operatively coupled to the control unit for, in response to the control signal, introducing a tactile signal into a speed controller (110), in a user interface of the motor vehicle, for controlling the current speed of the motor vehicle .

The motor vehicle of claim 1, wherein the control unit is functionally integrated with an on-board computer of the motor vehicle.

The motor vehicle of claim 1, wherein the dependence is programmable or reprogrammable with respect to at least one of the following: one or more predetermined magnitudes of the speed at which the tactile signal is to be introduced; and an attribute of the tactile signal.

The motor vehicle of claim 3, wherein the attribute has a value that depends on the difference according to a predetermined profile (200; 300).

The motor vehicle of claim 4, wherein the value increases if the difference increases in a first part of the predetermined profile, wherein the difference is greater than zero.

6. The motor vehicle of claim 5, wherein: the value increases as the difference decreases in a second part of the predetermined profile, wherein the difference is less than zero; and an absolute magnitude of a change in the value per unit of speed in the first part is greater than the absolute magnitude of the change per unit of speed in the second part.

The motor vehicle of claim 3, wherein the one or more predetermined rates of speed are programmable or reprogrammable in the control unit via at least one of: a configuration user interface (112) of the system; 5 a wireless connection to a source (402) outside the motor vehicle; and a personal navigation device (502) that has stored information about speed limits in a road network.

The motor vehicle of claim 1, wherein: the control unit is adapted to control the actuator so that the tactile signal is absent in a range (210) of values of the difference around a difference of zero; and the range represents sizes of the current speed that differ from the predetermined size of the speed with a relatively small fraction of the predetermined speed. 15

The motor vehicle of claim 1, wherein the actuator is physically integrated with the speed controller.

10. A system (102) for feedback to a user and for use in a motor vehicle (100) designed for use on public roads, wherein the system comprises: a control unit (104) for generating a control signal in dependence of a difference between a magnitude of a current speed of the motor vehicle and a predetermined magnitude (208) of the speed; and an actuator (108) operatively coupled to the control unit for, in response to the control signal, introducing a tactile signal into a speed controller (110), in a user interface of the motor vehicle, for controlling the current speed of the motor vehicle .

The system of claim 10, wherein the dependency is programmable or reprogrammable with respect to at least one of the following: one or more predetermined sizes of the speed at which the tactile signal is to be introduced; and an attribute of the tactile signal.

The system of claim 11, wherein the attribute has a value that depends on the difference according to a predetermined profile (200; 300).

The system of claim 12, wherein the value increases if the difference increases in a first part of the predetermined profile, wherein the difference is greater than zero.

The system of claim 13, wherein: the value increases as the difference decreases in a second part of the predetermined profile, wherein the difference is less than zero; and an absolute magnitude of a change in the value per unit of speed in the first part is greater than the absolute magnitude of the change per unit of speed in the second part.

The system of claim 11, wherein the one or more predetermined rates of speed are programmable or reprogrammable in the control unit via at least one of: a configuration user interface (112) of the system; a wireless connection to a source (402) outside the motor vehicle; and a personal navigation device (502) that has stored information about speed limits in a road network.

The system of claim 10, wherein: the control unit is adapted to control the actuator so that the tactile signal 25 is absent in a range (210) of values of the difference around a difference of zero; and the range represents sizes of the current speed that differ from the predetermined size of the speed with a relatively small fraction of the predetermined speed.

The system of claim 10, wherein the actuator is physically integrated with the speed controller.