Helmet detection of a motorcycle driver
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.
1 . A sensor system for a single-track vehicle, comprising at least one ultrasonic 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 at least one ultrasonic sensor element and to calculate and/or decide, if the driver is wearing a helmet, wherein the electronic control unit is connected to at least one vehicle system, which is controlled by the electronic control unit, wherein the electronic control unit is designed to calculate a reflection coefficient of a 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 a medium of a transmission environment, and wherein the electronic control unit is designed to provide, if the electronic control unit decides that the driver is not wearing a helmet, at least one of: at least one of a control or actuation to disable the ignition of the vehicle, as a vehicle system; at least one of an acoustic or visual warning to the driver; or a limiting of the speed of the vehicle.
2 . The sensor system according to claim 1 , wherein the at least one ultrasonic sensor element is placed at or on or beside an instrument cluster.
3 . The sensor system according to claim 1 , 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
=
(
(
Z
2
-
Z
1
)
/
(
Z
2
+
Z
1
)
)
2
,
wherein Z 1 is the acoustic impedance of the medium of the transmission environment and Z 2 is the acoustic impedance of the driver's head/face surface.
4 . The sensor system according to claim 1 , wherein the at least one ultrasonic sensor element is mounted in the way, that a direction of detection of the at least one ultrasonic sensor element can be changed by moving the at least one ultrasonic sensor element with regard to its sensitive direction.
5 . The sensor system according to claim 4 , wherein the at least one ultrasonic sensor element is laterally fixed, but moveable with regard to its detection direction and/or angle of direction controlled by the electronic control unit.
6 . A method for detecting a helmet of a driver of a single-track vehicle, using a sensor system for the single-track vehicle comprising at least one ultrasonic 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 at least one ultrasonic sensor element and to calculate and/or decide, if the driver is wearing a helmet, wherein the electronic control unit is connected to at least one vehicle system, which is controlled by the electronic control unit, wherein the electronic control unit is designed to calculate a reflection coefficient of a 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 a medium of a transmission environment, wherein after at least one of a steering lock of the vehicle is unlocked or the ignition is activated, the at least one ultrasonic sensor element detects the surface of at least one of the driver's head or face, wherein the electronic control unit afterwards processes the data of the at least one ultrasonic sensor element and decides, if the driver is wearing a helmet, wherein if the driver is wearing no helmet, at least one of i) the ignition will be disabled, ii) the ignition will not be enabled, iii) an acoustic warning will be provided to the driver, and iv) a visual warning will be provided to the driver.
7 . The method according to claim 6 , wherein the at least one ultrasonic 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 of these ultrasonic pulses is received by the at least one ultrasonic sensor element and the at least one ultrasonic sensor element provides the data to the electronic control unit.
8 . The method according to claim 6 , wherein the electronic control unit uses amplitude detection to detect with the at least one ultrasonic sensor element, if the driver is wearing a helmet.
9 . The method according to claim 6 , wherein the electronic control unit uses frequency analysis of the data of the at least one ultrasonic sensor element, to decide, if a helmet is detected.
10 . The method according to claim 6 , 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.
11 . The method according to claim 10 , 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.
12 . The method according to claim 6 , 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.
13 . The sensor system according to claim 4 , wherein the at least one ultrasonic 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.
14 . The method according to claim 6 , wherein the method of detecting, if the driver is wearing a helmet is continuous or repeated after a defined time interval, as long as the ignition of the vehicle is active.