HELMET DETECTION OF A MOTORCYCLE DRIVER

Abstract

A sensor system for a single-track vehicle, including at least one sensor element positioned for detecting the surface of a driver's head and/or face of that vehicle, an electronic control unit to process the data of the sensor element and to calculate and/or decide, if the driver is wearing a helmet. The electronic control unit is connected to at least one vehicle system, which is controlled by the electronic control unit.

Claims

1. A sensor system for a single-track vehicle, comprising at least one sensor element positioned for detecting the surface of a driver's head and/or face of that vehicle, an electronic control unit to process the data of the sensor element and to calculate and/or decide, if the driver is wearing a helmet, wherein the electronic control unit (10) is connected to at least one vehicle system, which is controlled by the electronic control unit.

2. The sensor system according to claim 1, wherein the at least one sensor element is an ultrasonic sensor element.

3. The sensor system according to claim 1, wherein at least two of the sensor elements are placed at or on or beside an instrument cluster.

4. The sensor system according to claim 1, wherein the electronic control unit is designed to provide a control and/or actuation to disable the ignition of the vehicle, as a vehicle system, and/or to provide an acoustic and/or visual warning to the driver and/or limiting the speed of the vehicle, if the electronic control unit decides, that the driver is not wearing a helmet.

5. The sensor system according to claim 1, wherein the electronic control unit is designed to calculate a reflection coefficient of the sensor signal of the at least one ultrasonic sensor element to decide, as a first criterion, if the driver is wearing a helmet, wherein the reflection coefficient is calculated dependent on a quotient of an acoustic impedance of the driver's head and/or face surface and an acoustic impedance of the medium of the transmission environment.

6. The sensor system according to claim 5, wherein the electronic control unit is designed to calculate a reflection coefficient R, as the first criterion, according to or dependent on the following equation $R={\left(\left(Z_2-Z_1\right)/\left(Z_2+Z_1\right)\right)}^2,$ wherein Z.sub.1 is the acoustic impedance of the medium of the transmission environment and Z.sub.2 is the acoustic impedance of the driver's head/face surface.

7. The sensor system according to claim 1, wherein the at least one sensor element is mounted in the way, that the a direction of detection of the sensor element can be changed by moving the sensor element with regard to its sensitive direction.

8. The sensor system according to claim 7, wherein the at least one sensor element is laterally fixed, but moveable with regard to its detection direction and/or angle of direction controlled by the electronic control unit.

9. A method for detecting a helmet of a driver of a single-track vehicle, using a sensor system according to claim 1, wherein after a steering lock of the vehicle is unlocked and/or the ignition is activated, at least one sensor element detects the surface of the driver's head and/or face, wherein the electronic control unit afterwards processes the data of the sensor element and decides, if the driver is wearing a helmet, wherein if the driver is wearing no helmet, the ignition will get disabled or not enabled and/or an acoustic and/or visual warning will be provided to the driver and preferably the method of detecting, if the driver is wearing a helmet is continuously or repeated after a defined time interval, as long as the ignition of the vehicle is active.

10. The method according to claim 9, wherein the at least one sensor element is an ultrasonic sensor element and the sensor element performs a beam sweep of ultrasonic pulses, controlled by the electronic control unit, towards the driver's head or face, wherein the echo if these ultrasonic pulses is received by the sensor element and the sensor element provide the data to the electronic control unit.

11. The method according to claim 9, wherein the electronic control unit uses amplitude detection to detect with the sensor element, if the driver is wearing a helmet.

12. The method according to claim 9, wherein the electronic control unit uses frequency analysis of the data of the sensor element, to decide, if a helmet is detected.

13. The method according to claim 9, wherein the electronic control unit calculates a reflection coefficient of the sensor signal, as a first criterion, of the at least one ultrasonic sensor element to decide, if the driver is wearing a helmet, wherein the reflection coefficient R is calculated dependent on the quotient of the acoustic impedance of the driver's head or face surface and the acoustic impedance of the medium of the transmission environment.

14. The method according to claim 9, wherein the electronic control unit performs a self-diagnosis of the sensor system before calculation and/or deciding if the driver is wearing a helmet.

15. The method according to claim 14, wherein the electronic control unit performs a calibration after the self-diagnosis of the sensor system and before the calculation and/or deciding if the driver is wearing a helmet.

16. The method according to claim 13, wherein the electronic control unit calculates a validation parameter, as a second criterion for the decision, if the driver is wearing a helmet, wherein the validation parameter is calculated dependent on the multiplication of the time of flight TOF and the amplitude of the sensor signal.

17. The sensor system according to claim 7, wherein the at least one sensor element is laterally fixed, but moveable with regard to its detection direction and/or angle of detection by an electric motor controlled by the electronic control unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIGS. 1 to 4 show schematic examples of the sensor system, its use and the method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] FIG. 1A discloses the function of an ultrasonic sensor element 1 as an example, wherein the ultrasonic sensor element 1 emits a wave 3 towards an object 2 and receives the reflected wave 4.

[0038] FIG. 1B shows an example, wherein the object 2 to detect is a helmet made of plastic, in particular of polycarbonate. The Ultrasonic sensor element 1 emits an ultrasonic wave 3 towards an object 2 and receives the reflected wave 4, wherein the medium of the transmission environment is air.

[0039] FIG. 2 illustrates an exemplary mapping of detection of the sensor element done dependent on the time of flight, TOF, of the wave and reflection and the amplitude of the reflection. The calculation of the reflection coefficient is done dependent on a multiplication of TOF value and Amplitude value. For a single sensor element, which is not moveable in respect to its detection direction the sensor element can only detect on area, which is illustrated by the circle. If the sensor element is adjustable by its detection direction or in case the sensor system uses multiple sensor elements, more areas, like P1 to P9 exemplary can be detected.

[0040] FIG. 3 shows an example of the sensor system. The inputs and outputs of an array of four sensor elements 1 are connected to electronic control unit 10. Within the electronic control unit, the controller 11 is performing the main calculations and the main method. Controller 11 is driving pulse generator 12 to provide a pulse signal, that is used by transducers driver 13 to provide a signal to drive the ultrasonic sensor elements. Transceiver 14 is forwarding that drive signal by demultiplexer 16 to the different sensor elements 1 of the array to emit an ultrasonic wave and to receive the reflected wave each with multiplexer 17. The sensor signal of the reflected wave of a certain sensor element is than forwarded by junction box 15 to a TOF unit 18, which calculates the time of flight and provides that TOF to the controller 11 and in parallel the sensor signal of the reflected wave to an amplitude measurement unit 19, which provides the calculated/measured amplitude also to the controller 11. The controller 11 calculates a reflection coefficient, as a first criterion for the decision, if the driver is wearing a helmet, wherein the reflection coefficient R is calculated dependent on the quotient of the acoustic impedance of the driver's head/face surface and the acoustic impedance of the medium of the transmission environment wherein a helmet is particularly detected, if the unit reflection coefficient R is in the range from 0.93 to 1.5, and if reflection coefficient R if smaller than 0.93 or greater than 1.5, the driver is wearing no helmet as an example for values, which are case by case dependent at least on the distance between the drivers head/face and the sensor element.

[0041] Additionally controller 11 calculates a validation parameter, as a second criterion for the decision, if the driver is wearing a helmet, wherein the validation parameter is calculated dependent on the multiplication of the time of flight, TOF, and the amplitude of the sensor signal, wherein the TOP is particularly calculated from the moment of emitting, preferably an ultrasonic wave, until the moment of receiving the reflection signal/reflected ultrasonic wave. In case the validation parameter has a value of a defined range or outside, the controller 11 decides, that the driver is wearing a helmet or not according to the second criterion. In this example, the sensor system comprises an array of sensor element 1, the multiplication of TOF and amplitude is for example a matrix calculation of the TOF matrix, where each sensor has one matrix parameter/value and the amplitude matrix, where each sensor provides one matrix parameter/value.

[0042] In total the controller 11 decides, if the driver is wearing a helmet according to the first and second criterion.

[0043] According to FIG. 4 the method is exemplarily illustrated. At first the sensor system is active after the handle lock of the motorcycle is unlocked A. Thereafter a self-diagnosis B is started, that especially checks, if the sensor elements/transducers are blocked by dust, mud, snow or other dirt. If such a contamination/dirt is detected, the driver is warned to clean the sensor elements C.

[0044] When the sensor elements are not blocked, the sensor elements are directed towards the driver's head/face, especially if direction is adjustable and a sweep of the sensor element is emitted D, for example a sweep of an ultrasonic wave. The according reflection signal/echo signal is detected E, wherein at first, before the regular measuring and calculation a calibration of the sensor system is performed E.

[0045] Dependent of TOF and the measured amplitude and dependent on the quotient of the acoustic impedance of the driver's head/face surface and the acoustic impedance of the medium of the transmission environment the decision is done, if the driver is wearing a helmet/if a helmet is detected F.

[0046] If a helmet is detect, the sensor system enables the ignition H and for an example confirms the driver/sends data accordingly to other control units of the vehicle.

[0047] In case a helmet was not detected/the decision was made, that the driver is not wearing a helmet, the driver is warned by a warning lamp/warning sound the ignition is for example kept inactive or the vehicle speed is limited G.