CLIAMS:[022] CLAIMS:
We claim:
1. A method for controlling speed of a vehicle traveling in cruise control mode, the method comprising the steps of:
a) operating an image capturing device on the vehicle at regular time intervals to capture one or more thermal images of the road surface and/or a leading vehicle ;
b) analysing each captured image for determining temperature profile of the road surface and/or the leading vehicle to detect change in road surface and/or momentum of the leading vehicle;
c) determining a target speed for the vehicle depending upon the temperature profile determined from the captured images; and
d) adjusting/modifying the speed of the vehicle depending upon the target speed.

2. The method as claimed in claim 1, wherein the captured images includes at-least rear tyres of the leading vehicle and/or tyre trail on the road surface.
3. The method as claimed in claim 1, wherein the step of modifying the speed of the vehicle includes activating one or more brakes of the vehicle.

4. The method as claimed in claim 1, wherein the step of modifying the speed of the vehicle includes activating one or more brakes of the vehicle.
,TagSPECI:[001] DESCRIPTION OF THE INVENTION:
[002] The following specification particularly describes the invention and the manner in which it is to be performed:
[003] Technical Field of the Invention
[004] The invention relates to a cruise-control system for a vehicle, and more particularly to methods for controlling speed of the vehicle traveling in cruise-control mode.
[005] Background of the Invention
[006] Most modern vehicles are now equipped with cruise-control systems. The cruise-control systems enable a driver of the vehicle to set the vehicle in cruise-control mode whereby the cruise-control system automatically maintains speed of the vehicle at a pre-set speed. However, in case of an object or a vehicle in front of the vehicle in cruise-control mode, the driver may be required to intervene to prevent a collision. The more advanced cruise-control systems automatically overcomes this shortcoming by adjusting the speed of the vehicle on detecting an object or vehicle ahead of it so as to maintain at-least a safe distance from the object or vehicle ahead.
[007] One prior art, United States patent 5249128 discloses a vehicle speed control method and system, whereby a first vehicle is installed with an energy detector for detecting infrared energy emitted from a second vehicle. Accordingly, when the first vehicle is trailing the second vehicle the first vehicle detects an image of infrared energy emitted by the second vehicle. The image is analysed by a set of feature points to establish that the second vehicle is in front.
[008] The above methods and systems for controlling speed of the vehicle in cruise-control mode solely rely on the cruise-control system. Further, in case of failure of the cruise-control system, the vehicle may require an alternative or back-up of the on board cruise-control system.
[009] Summary of the Invention
[010] Accordingly, the present invention in an aspect provides a method for controlling speed of a vehicle in cruise-control mode, the method comprising the steps of operating an image capturing device on the vehicle at regular time intervals to capture one or more thermal images of the road surface and/or a leading vehicle; analysing each captured image for determining temperature profile of the road surface and/or the leading vehicle to detect change in road surface and/or momentum of the leading vehicle; determining a target speed for the vehicle depending upon the temperature profile determined from the captured images; and adjusting/modifying the speed of the vehicle depending upon the target speed.
[011] Brief Description of Drawings
[012] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
[013] Figure 1 shows a flowchart of a method for controlling speed of a vehicle in cruise-control mode in accordance with an embodiment of the invention.

[014] Detailed Description of the Invention
[015] The present invention provides a method for controlling speed of a vehicle in cruise control mode. The present invention is directed towards altering speed of the vehicle depending upon road surface condition and/or a vehicle traveling in front of the vehicle.

[016] Figure 1 shows a flowchart of a method for controlling of a vehicle in cruise-control mode in accordance with an embodiment of the invention. In order to implement such a method, the invention is used or integrated with a cruise control system of a vehicle. According to the present invention, the invention is integrated with an adaptive cruise control system.

[017] The method begins at step 1A, where an image capturing device is operated at regular time intervals to capture one or more thermal images of road surface on which the vehicle is travelling and/or a leading vehicle ahead of the vehicle. In this regard, once the vehicle is set to travel in cruise-control mode, the image capturing device is continuously operated. The image includes at-least rear tyres of the leading vehicle and/or tyre trail on the road surface. According to the present invention, the image capturing device is a far infrared camera which captures thermal images. Installation and orientation of the image capturing device is a design consideration and will vary from vehicle to vehicle.

[018] At step 1B, each of the captured thermal images are analysed for determining temperature profile of the road surface and/or the leading vehicle captured in the image to detect change in road surface and/or momentum of the leading vehicle. According to the present invention, the temperature profile of the rear tyres of the leading vehicle and the tyre trail left on the road surface are analysed. As is known, if the vehicle stops suddenly or the vehicle skids, the temperature of the tyres of the vehicle increase as well temperature of the surface on which the vehicle has travelled or the temperature of the tyre-trail increases. Also, if the road surface has liquid or potholes filled with water, the temperature profile of the road surface will change. Accordingly, by determining the temperature profile of the road surface, tyres as well as the tyre-trail gives information of sudden change in road surface and/or change in momentum of the leading vehicle.
[019] At step 1C, depending upon the temperature profile determined from the captured image, a target speed for the vehicle is determined. Accordingly, depending upon the target speed determined, the method moves to step 1D where the speed of the vehicle is adjusted/modified. As isknown in the art, a vehicle is equipped with auxiliary brakes such as engine brake, exhaust brake, retarder brake, jake brake, etc. One or more brakes of the vehicle can be activated through ABS or ESP modules depending upon the determined target speed to adjust the speed of the vehicle.

[020] Advantageously, the present invention in addition to the adaptive cruise control system verifies the road surface and/or change in momentum of the leading vehicle. Also, in case of failure of the adaptive cruise-control system, the present invention can continue to provide information regarding the road surface and/or change in momentum of the leading vehicle.

[021] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.