WO2010004017A2

WO2010004017A2 - Path tracking illuminating device to be used on motorised vehicles having wide roll and pitch, and method associated thereto

Info

Publication number: WO2010004017A2
Application number: PCT/EP2009/058785
Authority: WO
Inventors: Niccolò BALDANZINI; Marco Pierini; Giovanni Savino
Original assignee: Universita' Degli Studi Di Firenze
Priority date: 2008-07-11
Filing date: 2009-07-10
Publication date: 2010-01-14
Also published as: ITPD20080207A1; WO2010004017A3; IT1391142B1

Abstract

Tracking illuminating device for motorised vehicles - and associated method - including an actuator (10) adapted to allow two degrees of freedom of movement to the device associated thereto and an electronic control module (11) associated to the said actuator (10) characterised in that the said actuator (10) comprises a light source and means adapted to modify the light beam orientation of the said light source.

Description

"PATH TRACKING ILLUMINATING DEVICE TO BE USED ON MOTORISED VEHICLES HAVING WIDE ROLL AND PITCH, AND METHOD ASSOCIATED THERETO"

FIELD OF THE INVENTION The present invention relates to a device, and method associated thereto, adapted to improve the illumination of the road under poor or absent natural light conditions by vehicles, such as motorcycles, performing bends by laterally tilting. STATE OF THE ART One problem related to the active safety affecting all the motorised vehicles having wide roll and pitch without distinction, and in particular motor vehicles, is the poor road visibility during night driving, due to the inappropriate illuminating system consisting of the conventional headlight.

A headlight should ideally produce the maximum illumination on the road and all factors related to the road which are required for a safe driving (path, road surface, traffic signs, pedestrians and objects at the road edges). These elements are used to set the trajectory to be followed and possibly highlight the need for taking emergency manoeuvres. However, the headlight should simultaneously avoid the production of glare effects both for the driver and for the vehicles traveling in the opposite direction. A wide lighting of the environment requires large light intensities emitted by the headlight which badly match with the need for avoiding the abovementioned glaring effects. Therefore, the actual illumination of the motor vehicle should find a good arrangement between the opposing needs. In order to solve the illumination problems, the solution which is usually adopted on vehicles is to share the functions between two discrete devices: full headlight and dipped headlight. The former illuminates the road and the road edge at a short distance, without directing the beam to the lane opposite to the travel one. The latter produces a very deep light beam, even reaching a certain distance, but having the disadvantage of glaring the drivers of vehicle traveling on the opposite lane. The driver alternately selects the on-switching of either headlights, depending on the driving situation. Along very winding paths, the full headlight is kept switched-on as long as possible, so that the road is seen at best. When meeting another vehicle, instead, switching to the dipped headlight is always required.

It is a great inconvenience for the driver to be required to continuously switch the switched-on headlight under any condition. But the major problems occur when bending, as delaying the shift from full headlight to dipped headlight may cause the other vehicle to be glared, exactly in the critical exchange situation when bending, whereas only keeping the dipped headlight active does not allow the road to be sufficiently illuminated. Furthermore, the dipped headlight may be shown as not completely eliminating the glare phenomenon when bending if the roll angles are greater than 10 degrees and therefore trying to obtain an automatic switching between the two types of headlights is not useful.

Another solution could be using one headlight only, provided with features other than both the dipped headlights and the full headlights. With this regards, it is worth noting, however, that there is no headlight geometry adapted to correctly illuminate the road with any roll angles of the motor vehicle and without producing any glare for the other vehicles; therefore, the simplest solution to be used to solve the illumination matter includes the ability of favorably orienting the optical axis of a traditional dipped headlight towards the road.

In the state of the art, there exist some solutions to the disclosed technical problem which develop new concept headlights for improving the visibility during the bending step of a two-wheeled vehicle, but each implies a number of drawbacks which make the application thereof difficult or poorly effective. In patent document JP10324191 , there is described a device for moving a vehicle headlight controlled by processing several parameters such as, inter alia, bump position, steering angle, roll angle and vehicle speed. Said device is characterised by a control system having a high complexity degree, based on reading and processing several parameters complicating the construction and operation thereof.

In patent document JP1 186486 there is described a device for moving a vehicle headlight controlled by processing the readings of vehicle speed and steering angle in order to set an illumination correction by means of a so-called yaw rotation, i.e. a rotation with respect to a vertical axis. Moreover, the reading of the roll angle of the motor vehicle is further processed and, according thereto, a rotation of the headlight about the longitudinal axis is performed, which rotation has a modulus equal to the roll and an opposite direction. This system also appears to be complicate and with a non-optimal operation, as the rotation along the longitudinal axis is inconvenient for purposes of illumination improvement when bending. Furthermore, the correction logic does not use the parameter represented by the reading of the steering angle which is essential to reach the desired effectiveness level.

In patent documents US5599085 and US6309093 there are described systems for modifying the headlight illumination distribution so as to increase the road portion which may be seen by the driver, and novel headlights modifying the generated light beam shape are introduced by varying the geometry thereof. The disclosed solution however implies the development and construction of a new-type headlight without solving the problem related to the possibility of still using traditional headlights so as to be able to easily provide for the existing vehicle retrofitting.

SUMMARY OF THE INVENTION

The present invention relates to a path tracking illuminating device to be used on motorised vehicles having wide roll and pitch, characterised in that it comprises one or more light sources which may be oriented by means of an electromechanical actuator and/or adjusted in intensity, and an electronic control system which controls the light beam direction.

The device at issue is further characterised in that it ensures the optimal illumination in every situation according to a control logic which allows to map the best light beam direction in advance for each roll and pitch angle of the vehicle and for each road route profile and bending. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a block diagram of the device according to the present invention. Figure 2 shows a schematization of a preferred embodiment of the kinematic mechanism used in the device according to the present invention. Figure 3 shows a schematization of a preferred embodiment of the electromechanical actuator used in the device according to the present invention. Figure 4 shows a flow chart of a preferred embodiment of the method of controlling tracking illuminating devices for motorised vehicles according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The device according to the present invention is able to solve the disclosed technical problem regarding the need for ensuring a greater road visibility during night driving, in particular when bending, to motorised vehicles having wide roll and pitch, in particular motor vehicles.

Therefore, the present invention introduces a light beam capable of automatically orient towards the road. Specifically, when bending, instead of being pointed in a straight direction with respect to the vehicle, and therefore towards the external edge of the road thus leaving the road part of interest in the dark, it is oriented towards the interior of the bend itself, thus accurately illuminating it. In order to fully appreciate the usefulness of the device, it should be noted that each motorcycle mounting the front headlight as integral with the handlebar has the above-disclosed problem of illumination when bending. In fact, the handlebar rotation angles when bending at a speed exceeding 30 km/h are lower than 5°, whereas the rotations required to correct the illumination direction may reach 60°. The present invention allows to set the orientation direction of the light beam during the motion by using two parameters instant by instant: the roll angle and the motor vehicle speed. By processing these two data only, the traveling route conformation may be derived in each moment. At this point, a control unity chooses the appropriate direction, identified with respect to the longitudinal axis of the motorcycle, towards which the headlight should be oriented for best illuminating the road. With reference to accompanying Figure 1 , the device according to the present invention consists of three discrete elements: an actuator 10, an electronic control module 1 1 associated thereto and such that it carries out the method implementing the correction logic 12 adapted to calculate the working parameters instant by instant from the detected data related to the vehicle motion. Said actuator 10 comprises a light source and means adapted to modify the orientation of said light source, in detail it preferably comprises a headlight 20, even of traditional type, a kinematic mechanism of movimentation 21 associated thereto and at least one further actuator 22 adapted to move said kinematic mechanism.

Said actuator 10, preferably of electromechanical type, is further adapted to allow two degrees of freedom of movement to the headlight associated thereto. For this purpose, and with reference to accompanying Figure 2, a kinematic mechanism is preferably used, which is adapted to perform a rotation ξ about a vertical axis, belonging to the symmetry plane of the motorcycle, and a rotation η (composite as compared to the former) about a horizontal axis orthogonal to the axis of the motor vehicle, when the first rotation is zero. The disclosed type of kinematic mechanism is such that it minimizes the angles required to correct the illumination during the roll movements, indeed both by means of changing the rotation order and changing the rotation type, the orientation of the headlight on the road would require wider angles of rotation about the various rotation axes in the whole operation field. Moreover, rotation η gives the possibility of modifying the headlight orientation by lifting and lowering the beam, in order to improve the illumination on a straight road stretch, during the pitch movements of the vehicle. With reference to accompanying Figure 3, a preferred embodiment of said actuator 10 is seen in detail. There is a headlight 20, preferably of the lentiform type, and moreover said kinematic mechanism of movimentation 21 associated thereto comprises a support 31 associated to said headlight 20, a connecting rod 32 and a crankshaft 33 both associated to said support 31 and adapted to provide said headlight 20 with the pitch movimentation. Said kinematic mechanism of movimentation 21 further comprises a second support 38 associated to said connecting rod 32 and said crankshaft 33, and a support chassis 39 integral with the vehicle chassis. Said at least one further actuator 22 adapted to move said kinematic mechanism comprises at least two motors and appropriate interface means towards said kinematic mechanism of movimentation 21. For example, said at least two motors comprise a first motor 34, preferably of the electric type, adapted to rotate said support 31 about its own vertical axis thus modifying the value of yaw angle thereof, and a second motor 35, also preferably of the electric type, adapted to rotate said support 31 about its own horizontal axis, thus modifying the value of the pitch angle thereof. Finally, said appropriate interface means towards said kinematic mechanism of movimentation 21 advantageously comprise a pair of pulleys 36, 37 adapted to transmit the motion of said first motor 34 to said headlight 30 which is firmly connected to said support 31 , which is in turn connected to said second support 38 by means of said connecting rod 32 and said crankshaft 33. For example, said second support 38 is further connected by means of a brass ring to said support chassis 39 and to a pulley 36 of said pair of pulleys 36, 37 adapted to transmit the yaw movimentation thereto and connected to said second motor 35 by means of said crankshaft 33. The control electronics 1 1 of the device according to the present invention preferably comprises: at least one sensor 23, adapted to read the roll speed of the motor vehicle (e.g. by means of a gyroscopic sensor) and its linear speed or the angular speed of its front wheel (e.g. by means of a phonic wheel from which the linear speed may then be calculated), a programmable logic unity 24 and a driving unity 25 adapted to control said at least one further actuator 22 above. Said correction logic 22 acts so as to derive the appropriate correction from the measures of speed and roll angle of the vehicle, in order to then provide said actuator 10 of the electromechanical type with the position to be taken by the headlight. Alternatively, said actuator 10 may be such that it drives the on-switching, off- switching or adjustment of a plurality of point light sources used instead of said headlight 20, or may still be such that it drives geometry variations of reflective elements associated to the used light sources, reflective elements which may be of the movable or deformable type. With reference to accompanying Figure 4, the method of calculation applied to said correction logic includes that readings 40 of the data from said at least one sensor 23 are acquired, and the linear speed value 42 and the roll speed value 43 of the vehicle are then calculated. The calculation of the instantaneous roll angle value 44 is then carried out, e.g. by integrating the roll speed previously measured by a gyroscopic sensor. Once the roll speed and angle of the motor vehicle are available, the curve radius 45, which the motor vehicle itself is running, is calculated. The bend being known (by means of the curve radius), the position of the motor vehicle with respect to the road being known (by means of the roll angle) and the illumination features of the used light source being known, the best orientation of the light beam with respect to the ground may be univocally set through the calculation 46 of the correction factors of the yaw and pitch angles. Said calculation 46 of the correction factors may be carried out, for example, in a virtual environment with the aid of means for electronically processing data, with the previous and proper creation of a parametric road bend, a motorcycle model which may be inclined for simulating the roll and pitch angles, and a further model representing the distribution of the light generated by the light source to be used. In such a virtual environment, each configuration of curve radius and motorcycle inclination may be recreated, so as to derive the best orientation of the light beam instant by instant. More in detail, in a preferred embodiment of the present invention, said calculation 46 of the correction factors is carried out such that, for each value of curve radius r and for each value of roll angle φ, two orientation angles ξ (about a vertical axis, belonging to the symmetry plane of the motorcycle) and η (about a horizontal axis orthogonal to the motorcycle axis) of the light beam are calculated, so that the illuminated area in one's own carriageway of one's own travel direction is maximum and the illuminated area in the carriageway of the opposite travel direction is minimum. Said values of curve radius r and roll angle φ are calculated from the readings of said at least one sensor 23. For example, sensors for reading the longitudinal speed of vehicle v and the roll angle variation dφ/dt may be used, such as for example gyroscopic sensors, or sensors for reading the longitudinal speed of vehicle v and the yaw angle variation speed dΩ/dt integrally calculated with the motorcycle chassis may be used. Alternatively, the aforesaid parameters r and φ may be directly read if said at least one sensor 23 comprises an inertial platform or a "state estimator" module and a GPS module. In a preferred embodiment of the present invention, sensors for reading the vehicle longitudinal speed V and the yaw angle variation speed dΩ/dt integrally calculated with the motorcycle chassis are used. By this calculation method, the roll angle is calculated by avoiding the production of an error accumulation over time, during the calculation itself, which instead occurs by integrating the starting datum of the roll speed, for example. In this case, the expression of the roll angle is as follows: φ= arctan (V²/ g) ^* V[(Ω'² g) / (g² V² - Ω'² V⁴)] where: V is the vehicle longitudinal speed; g is the acceleration due to gravity; Ω' is the yaw angle variation speed.

The method of calculation based on the expression of the roll angle by means of the previous formula may advantageously be used even in other applications, e.g. it may provide the operation logic of systems controlling the traction/braking for motorcycles and two-wheeled vehicles with information on the roll angle, or may also provide automatic object recognition systems, in particular for applications in the motorcycle field, with information on the roll.

Claims

1. Tracking illuminating device for motorised vehicles including an actuator (10) adapted to allow two degrees of freedom of movement to the device associated thereto and an electronic control module (1 1 ) associated to the said actuator (10) characterised in that the said actuator (10) comprises a light source and means adapted to modify the light beam orientation of the said light source.

2. Device according to claim 1 characterised in that the said light source and the said means adapted to modify the light beam orientation of the said light source comprise a headlight (20), a kinematic mechanism of movimentation

(21 ) associated thereto and at least a further actuator (22) adapted to move the said kinematic mechanism of movimentation (21 ).

3. Device according to claim 2 characterised in that the said kinematic mechanism of movimentation (21 ) is adapted to perform a rotation ξ around the vertical axis, belonging to the plane of simmetry of the said vehicle, and a rotation η around an horizontal axis perpendicular to the said vehicle axis.

4. Device according to claim 3 characterised in that the said rotation η is composed in respect of the said rotation ξ.

5. Device according to claims 1 - 4 characterised in that the said kinematic mechanism of movimentation (21 ) comprises a support (31 ) associated to the said headlight (20), a connecting rod (32) and a crankshaft (33) connected to the said support (31 ) and adapted to provide the said headlight (20) with the pitch movimentation, a second support (38) associated to the said connecting rod (32) and to the said crankshaft (33) and a support chassis (39), integral with the chassis of the said vehicle.

6. Device according to claims 1 - 5 characterised in that the said at least a further actuator (22) adapted to move the said kinematic mechanism of movimentation (21 ) comprises at least two motors and suitable interface means towards the said kinematic mechanism of movimentation (21 ).

7. Device according to claim 6 characterised in that the said at least two motors comprise a first motor (34) adapted to rotate the said support (31 ) around its own vertical axis modifying the degree of the yaw angle and a second motor (35), adapted to rotate the said support (31 ) around its own horizontal axis modifying the degree of the pitch angle.

8. Device according to claim 6 characterised in that the said first motor (34) and the said second motor (35) are of electrical type.

9. Device according to claims 6 - 8 characterised in that the said suitable interface means towards the said kinematic mechanism of movimentation (21 ) comprise a couple of pulleys (36, 37) adapted to transmit the motion of the said first motor (34) to the said headlight (30) which results to be rigidly connected to the said support (31 ), that is, in turn, connected to the said second support (38) by means of the said connecting rod (32) and the said crankshaft (33).

10. Device according to claims 5 - 9 characterised in that the said second support (38) is connected to the said support chassis (39) and to a pulley (36) of the said couple of pulleys (36, 37) adapted to transmit the yaw motion to it and it is further connected to the said second motor (35) by means of the said crankshaft (33).

1 1. Device according to claim 10 characterised in that the said second support (38) is connected to the said support chassis (39) by means of a brass ring.

12. Device according to claim 1 characterised in that the said light source and the said means adapted to modify the light beam orientation of the said light source comprise means adapted to drive the on and off switching or the regulation of a plurality of punctiform light sources.

13. Device according to claim 1 characterised in that the said light source and the said means adapted to modify the light beam orientation of the said light source comprise means adapted to drive variations of geometry of reflecting elements connected to the light sources employed, being these reflecting elements of movable type or of deformable type.

14. Device according to claims 1 - 13 characterised in that the said electronic control module (1 1 ) comprises: at least a sensor (23), adapted to read the vehicle roll speed and its linear speed, a programmable logic unity (24) and a driving unity (25) adapted to control the said at least a further actuator (22).

15. Device according to claim 14 characterised in that the said at least a sensor (23) comprises a gyroscopic sensor.

16. Device according to claim 15 characterised in that the said at least a sensor (23) further comprises a phonic wheel.

17. Device according to claim 14 characterised in that the said at least a sensor (23) comprises devices chosen in the group comprising: sensors for the reading of the longitudinal speed of vehicle v and of the roll angle variaton dφ/dt; sensors for the reading of the longitudinal speed of vehicle v and of the yaw angle variaton dΩ/dt calculated in integral manner with the vehicle chassis; an inertial platform; a "state estimator" module and a GPS module.

18. Method for the calculation of the correction parameters for the said actuator (10) characterised in that it comprises the following steps: a) acquisition (40) of the readings of the data acquired from the said at least a sensor (23). b) calculation of the vehicle linear speed value (42). c) calculation of the vehicle roll speed value (43). d) calculation of the vehicle instantaneous roll angle value (44). e) calculation of the curve radius (45), which the vehicle is running. f) calculation (46) of the correction factors of the yaw and pitch angles.

19. Method according to claim 18 characterised in that the said calculation (46) of the correction factors is made in such a way that, for each curve radius r value and for each roll angle value φ, two orientation angles are calculated: ξ, around a vertical axis belonging to the vehicle plane of simmetry, and η, around an horizontal axis orthogonal to the vehicle axis, of the light beam so that the illuminated area of the travel lane of the vehicle is maximum and the illuminated area in the opposite travel lane is minimum.

20. Method according to claims 18 - 19 characterised in that the said curve radius r and roll angle φ values are calculated starting from the readings of the said at least a sensor (23).

21. Method according to claims 18 - 20 characterised in that sensors are employed for the reading of the vehicle longitudinal speed V and of the variation of the yaw angle dΩ/dt = Ω' calculated in integral manner with the vehicle chassis.

22. Method according to claims 18 - 21 characterised in that the yaw angle is calculated according to the following formula: φ= arctan (V² / g) ^* V[(Ω'² g) / (g² V² - Ω'² V⁴)] where: V is the vehicle longitudinal speed; g is the acceleration due to gravity; Ω' is the variation of the yaw speed.

23. Method for the calculation of the roll angle characterised in that the said roll angle is calculated according to the following formula: φ= arctan (V² / g) ^* V[(Ω'² g) / (g² V² - Ω'² V⁴)] where: V is the vehicle longitudinal speed; g is the acceleration due to gravity; Ω' is the variation of the yaw speed.

24. Method according to claim 23 characterised in that the calculation of the said roll angle is employed in control systems of traction/braking for motorcycles and two-wheeled vehicles.

25. Method according to claim 23 characterised in that the calculation of the said roll angle is employed in automatic object recognition systems for applications in the motorcycles field.