[001] The present subject matter described herein, relates to a system and a method for sway warning in vehicle, and in particularly, to a method and a system to detect sway movement of the vehicle on roads independent of lane markings by estimating lateral displacement of the vehicle and to warn the operator (driver) of the vehicle about the same.
BACKGROUND AND PRIOR ART:
[002] Automotive vehicles travel within defined lanes of a roadway, generally based on steering by an operator (driver) of the vehicle. Conventionally, vehicles are equipped with lane departure warning (LDW) systems that are designed to provide a warning indication if the vehicle departs from an identified lane of the roadway. In response to the warning, the driver of the vehicle may steer the vehicle back into the appropriate lane. Currently proposed lane departure warning systems typically include optical systems, such as camera configured to capture images of the roadway and to process the images to identify lane markings, such as painted lines, on the roadway.
[003] Conventional LDW systems suffer from disadvantages due to which these cannot be used on those areas where lane marking is not present or proper. 1. Majority of roads do not have Lane markings. 2. The lane detection is difficult in dark/night condition by the camera. 3. The lane color (white/yellow) fades off with time. This affects detection of lane markings due to poor contrast with road.
[004] Conventionally, there are some techniques which uses GPS data and stored learned path to determine lane of the road and based on the determined lane road identify the crossing of lane. However these systems are completely based on GPS data and stored learned path and cannot work when there is no stored learned path (cannot work in real time scenario). Further, these systems use camera to correctly identify the stored learned path to guide the vehicle in dark areas. But

these systems require proper lane marking to detect and warn the driver when vehicle cross the danger zone.
[005] Therefore, the LDW systems equipped with the camera cannot be used on roads which have no lane marking and/or low street lights. Accordingly, there is a requirement for a system which can work where there is no lane marking and even in dark/night conditions to detect crossing of lane and warn the driver about the same to correct the steering.
OBJECTS OF THE INVENTION:
[006] The principal object of the present invention is to provide a system and a method for detecting unintentional sway on road by vehicle.
[007] Another object of the present subject matter is to provide a system and a method for detecting unintentional sway based on steering angle, velocity of the vehicle and time.
[008] Another object of the present subject matter is to provide a method and a system to warn driver about upon detection of unintentional sway.
[009] Another object of the present subject matter is to provide a system and a method which detects and warns the driver about unintentional sway based on real time parameters.
[0010] Yet another object of the present subject matter is to provide a system and a method to issue visual and audio warning to the driver about unintentional sway.
[0011] Yet another object of the present invention is to provide a simple and inexpensive system for detecting unintentional sway on the roads independent of lane marking, or dark light conditions on the road and warning the driver about unintentional sway of vehicle.
SUMMARY OF THE INVENTION:
[0012] This summary is provided to introduce concepts related to detection of unintentional sway of vehicles. The present concept is independent of lane markings on the road. The concepts are further described below in the detailed

description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0013] In an embodiment, a method for detecting unintentional sway and generating warning in a vehicle without turn indication is described herein. In the present method, the sway warning controller begins with ascertaining of whether a turn indicator is ON or OFF and whether steering torque value is less than a threshold value. If the turn indicator is OFF, and if steering torque value is less than threshold value, then the vehicle is unintentionally swaying, and the sway warning controller generates warning based on calculated lateral displacement of the vehicle from the straight path at each sampling time. When calculated lateral displacement of the vehicle at any point of time is more than the threshold value, the method generates warning to the driver about unintentional sway of vehicle.
[0014] In another embodiment, a vehicle sway warning device for detecting unintentional sway and warning driver about unintentional sway is described. The vehicle sway warning device has a sway warning controller along with other controllers, such as steering angle controller, steering torque controller, yaw rate controller, GPS controller to receive inputs, such as steering angle value, steering torque value, vehicle velocity, and yaw rate to determine whether driver is swaying intentionally or unintentionally. When vehicle, crosses a threshold value, the sway warning controller issues a warning to the driver about the unintentional sway. The sway warning controller uses yaw rate controller and yaw rate sensor to detect unintentional sway in curved path.
[0015] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS
[0016] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0017] Fig. 1 illustrates block diagram of vehicle sway warning system, in accordance with an embodiment of the present subject matter;
[0018] Fig. 2 illustrates flow diagram to detect unintentional sway and warning driver about the same , in accordance with an embodiment of the present subject matter; and
[0019] Fig. 3 illustrates position of the vehicle on straight road and its lateral movement, in accordance with an embodiment of the present subject matter.
[0020] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0021] In the description herein, the present disclosure pertains to the vehicle sway warning system to detect unintentional sway and issues audio or video or both warnings to driver upon unintentional sway. By the present vehicle sway warning system, driver can be warned upon detection of unintentionalsway due to inattentiveness of the driver. As a result, accidents or vehicle collision on the road

or path can be avoided. The present vehicle sway warning system can also work efficiently on roads or pathways which do not have lane marking or in dark/low light conditions.
[0022] Various approaches may be used to detect and warn lane departure where lane markings are proper and visible. However, none of the approaches includes a mechanism of detecting the unintentional swayon roads where there is no lane marking and low visibility.
[0023] In an embodiment of the present subject matter, a method and a system is disclosed to detect unintentional sway and warn driver about the unintentional sway. The system has a sway warning controller which is in communication with other peripheral controllers of a plurality of sensors to receive inputs and process the received data. The sway warning controller ascertains whether turn indicator is ON or OFF. Upon ascertaining that turn indicator is OFF, the sway warning controller determines the steering torque value from steering torque sensor disposed in vicinity of the steering. Based on the determined steering torque value, the sway warning controller determines whether the driver is attentive or not. Further, the method receives steering angle value from the steering angle sensor disposed in vicinity of the steering and determines whether the steering angle is more than threshold steering angle. Simultaneously, the sway warning controller receives input value of vehicle velocity from vehicle velocity sensor and GPS coordinates from the GPS sensor. Upon ascertaining that the vehicle velocity is greater than a threshold limit and based on the GPS coordinates, the sway warning controller determines whether the path is straight or curved. Based on the determined path, when path is straight, the sway warning controller determines whether the steering angle value is more than the threshold steering angle value. When steering angle value is more than the threshold value, the sway warning controller calculates lateral displacement of the vehicle from the straight path for each sampling time. Upon calculating lateral displacement at each sampling time, the sway warning controller compares the lateral displacement with the threshold value. When calculated lateral displacement at any point of

time is more than the threshold value, the sway warning controller issues an audio or visual or both warning to the driver.
[0024] In another aspect of the present subject matter, when path is curved, the sway warning controller receives yaw rate from the yaw rate sensor via a yaw rate
5 controller. The sway warning controller compares the determined or received yaw rate with the yaw rate minimum threshold value and yaw rate maximum threshold value of the curved path for specified time duration. If received yaw rate is not within prescribed yaw rate at the curved path, whose lower threshold is YL and upper threshold is YH for time greater than threshold duration, the sway warning
10 controller issues an audio or visual or both warnings to the controller.
[0025] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily
15 utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples
20 recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the
25 present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.
[0026] These and other advantages of the present subject matter would be 30 described in greater detail with reference to the following figures. It should be
7

noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
5 [0027] FIG. 1 illustrates block diagram of vehicle sway warning system in accordance with an embodiment of the present disclosure. The vehicle sway warning system 200 (herein after interchangeably referred as system 200) which is implemented in vehicle to detect unintentional sway. The system 200 may be implemented as standalone device or in integration with other existing devices,
10 such as telematics device or ECU in the vehicle. The system 200 is provided on the vehicle to monitor movement of the vehicle and to detect departure of the vehicle from its intentional path, and to generate a warning to driver of the vehicle when the vehicle departs from its intentional path or road.
[0028] The system 200 is coupled with turn indicator 101, steering angle sensor 15 102, vehicle velocity sensor 103, GPS sensor 104, steering torque sensor 105, yaw rate sensor 106 via interface 202 to provide their corresponding input to the system 200. The turn indicator 101, the steering angle sensor 102, the vehicle velocity sensor 103, the GPS sensor 104, the steering torque sensor 105, and the yaw rate sensor 106 are peripheral devices which are coupled with the system to 20 provide real time or current plurality of inputs, such as turn Indication ON or OFF, steering angle value, vehicle velocity, GPS coordinates and map, steering torque value, and yaw rate of the vehicle. Based on these received real time inputs, the system 200 processes the inputs to detect unintentional sway and warn the driver about the same.
25 [0029] The interface 202 may include a variety of software and hardware interfaces, for example, interfaces for peripheral device(s), such as sensors, actuators, and an external memory. The hardware interface 202 is suitable for interfacing with the sensors as referred in the figure 1. The interface(s) 202 may include a variety of interfaces, for example, interfaces for data input and output
30 devices, referred to as I/O devices, storage devices, network devices, and the like.
8

The interface(s) 202 facilitate communication between the system 200 and various sensors and audio video units connected in the vehicle. The interface(s) 202 may also provide a communication pathway for one or more components of the system 200. The memory 201 may store one or more computer-readable instructions, 5 which may be fetched and executed to detect vehicle sway. The memory 201 may include any non-transitory computer-readable medium including, for example, volatile memory, such as RAM, or non-volatile memory, such as EPROM, flash memory, and the like.
[0030] The system 200 further includes controller(s) 203 and data 210. The 10 controller(s) 203 may be implemented as a combination of hardware and programming (for example, programmable instructions) to implement one or more functionalities of the system 200. In examples described herein, such combinations of hardware and programming may be implemented in several different ways, such as microcontroller or microprocessor. For example, the 15 programming for the controller(s) 203 may be processor executable instructions stored on a non-transitory machine-readable storage medium and the hardware for the controller(s) 203 may include a processing resource (for example, one or more processors), to execute such instructions.
[0031] The data 210 includes data that is either stored or generated as a result of 20 functionalities implemented by any of the controller(s) 203. The system 200 includes steering angle controller 204, GPS controller 205, steering torque controller 206, yaw rate controller 207, sway warning controller 208 and other controller(s) 209 which process the real time inputs received from their corresponding sensors. The other controller(s) 209 may implement functionalities 25 that supplement applications or functions performed by the system 200. Further, the data 210 may include sway warning data 211 and other data 212. The sway warning data 211 receives inputs from the sway warning controller 208 and provides the same to the sway warning controller 208 for further processing to achieve the desired objective.
9

[0032] The system 200 is incorporated in the vehicle and works when the vehicle unintentionally sways without giving turn indication. The system 200 is in communication with the turn indicator 101. When the vehicle is deviating from its straight path on the road, the system 200 ascertains whether turn indicator is ON 5 or OFF. If the turn indicator is ON, the system 200 do not process further receiving data and does not issue any warning as the present deviation is intentional by the driver. If the turn indication is OFF, and the driver deviates from the straight path, it is due to lack of attention while driving.
[0033] The system 200 includes the sway warning controller 208 which is 10 coupled with other controllers of the sensors to receive their inputs to determine unintentional sway of vehicle and to generate warning based on unintentional sway of vehicle. The sway warning controller 208 may be a programmed controller to process received real time inputs and to detect unintentional sway based on real time inputs. Upon affirmative ascertainment that turn indicator is 15 OFF, the sway warning controller 208 receives steering torque value from the steering torque controller 206. The steering torque controller 206 is coupled with the steering torque sensor 105 via the interface 202 to receive real time inputs and process the received real time inputs. The sway warning controller 208 compares the received steering torque value with threshold steering torque value to 20 determine whether the driver is attentive or not. When the steering torque value is less than the threshold steering torque value, the sway warning controller determines that the driver is in-attentive. In another embodiment, if the steering torque value is more or equal to the threshold value, the system 200 may be ignored for further processing.
25 [0034] The sway warning controller 208 receives the real time steering angle value from the steering angle controller 204 which is coupled with the steering angle sensor 102. Based on the steering angle value and the vehicle velocity at each sampling time and vehicle parameters, such as wheel base and steering angle ratio, the sway warning controller calculates and compares lateral displacement of
30 the vehicle at each sampling time with a threshold value.
10

[0035] When the driver corrects the steering torque value at any point of time during driving, the system 200 restarts to capture fresh inputs from the turn indicator, the steering torque sensor, the vehicle velocity sensor, and the steering angle sensor.
5 [0036] The sway warning controller 208 receives vehicle velocity from the vehicle velocity sensor. The sway controller 208 compares the vehicle velocity with threshold vehicle velocity. If the vehicle velocity is less than the threshold velocity, the sway controller 208 does not process any data for further computation.
10 [0037] In situations, where driver is in-attentive, turn indicator is OFF, and vehicle velocity is more than threshold velocity, the sway warning controller 208 receives GPS coordinates from the GPS controller 205. Based on the GPS coordinates, the sway warning controller 208 determines whether path is straight or curved.
15 [0038] A person skilled in the art would appreciate that all the real time inputs, such as steering torque value, steering angle value, vehicle velocity and GPS coordinates may be received at single instance. Based on the received inputs, the sway warning controller decides whether to process further or not. It is not necessary that the sway warning controller receives GPS inputs only after
20 processing the steering torque value and velocity inputs. The sway warning controller 208 may process all inputs simultaneously and decides whether to process or not based on above explained conditions.
[0039] When vehicle is moving on straight path as determined by the GPS coordinate, the sway warning controller 208 determines steering angle value from
25 the steering angle sensor 102 via steering angle controller 204. The steering angle controller 204 is coupled with the sway warning controller 208 and provides real time or current steering angle value. The sway warning controller 208 compares the steering angle value with threshold steering angle value. When the steering angle value is more than the threshold steering angle value, the sway warning
30 controller 208 determines turn radius based on the current steering angle value.
11

5
10

The turn radius (r) determines vehicle’s path on the road. Upon calculating of the turn radius (r), the sway warning controller 208 calculates lateral displacement (L) based on equations as mentioned illustrated with reference to Figure 3:
Referring to figure 3, formula for calculating lateral displacement (L) is
illustrated:
Circumference=2 nr → 360
For the vehicle to move from point A to point B, it should cover distance ‘d’
360 d = velocity ∗ time -> 6 =π ∗ d
2rr
/360 cos 6 = cos 2π ∗ velocity ∗ time
Vrr /
a y cos 6 = —
wheel base steering angle value
r = : ,a =
, where a is the angle by which the
steering angle ratio
wheel is turned at a particular steering angle value Steering Angle Ratio remains constant for a vehicle.
L = r — y
r

Wheel Base 360 ∗ velocity ∗ time

(Steering Angle Value
Steering Angle ratio) 2n ∗ Wheel Base
Steering Angle Value\ J Steering Angle ratio )) 11

ifL> Lth, then warning will be generated
15
[0040] As a person skilled in the art would appreciate that the above equations 20 and formulas are given to describe the best method for calculations of the lateral displacement. There can be other methods or equations which can be used to calculate the lateral displacement.
[0041] The sway warning controller 208 compares the calculated lateral
displacement (L) with threshold lateral displacement (Lth). When the calculated
25 lateral displacement (L) is more than the lateral threshold (Lth), the sway warning
12

controller 208 generates an audio or visual or both warning to the driver about lane detection.
[0042] In another embodiment, when vehicle is moving in curved path, the sway warning controller 208 receives yaw rate (Yr) from the yaw rate sensor 106 via
5 the yaw rate controller 207. The sway warning controller 208 compares the yaw rate (Yr) with the prescribed yaw rate having low threshold yaw rate ‘YL’ and upper threshold yaw rate ‘YH’ for particular turn path. The prescribed yaw rate can be determined from the GPS controller 205 for the particular turn path. The sway warning controller 208 compares the yaw rate ‘Yr’ with the prescribed yaw
10 rate of the turn for threshold time duration, i.e., time to complete the curved path which is based on vehicle speed. The vehicle velocities above a specific threshold limit, the time taken for unintentional sway away from the actual path is predefined in the system for various curved paths. The predefined specific threshold limit of velocity and time taken is stored in the memory 201. If the
15 vehicle's yaw rate ‘Yr’ is not within prescribed yaw rate at turns, whose lower threshold is ‘YL’ and upper threshold is ‘YH’ for time greater than threshold time duration, the sway warning system generates warning to the driver.
[0043] The sway warning controller 208 stores all computed and in process data on the sway warning data 211. The sway warning controller 208 sends warning 20 signal in form of audio or video or combination of both to the audio or video device 107. The audio or video device 107 is coupled with the system 200 via the interface 202 to generate warning message as programmed upon detection of warning signal from the system 200.
[0044] Referring to fig. 2 which describes a method for detecting unintentional 25 sway and generating warning upon detection of unintentional sway of vehicle, in accordance with an embodiment of the present subject matter. The method 300 discloses how present system works to detect unintentional sway of vehicle and to generate warning messages. As per the present method, the system 200 has a sway warning controller 208 interacting with other controllers to receive inputs 30 regarding turn indicator, steering torque value, steering angle value, vehicle
13

velocity and yaw rate to detect unintentional sway and warn the driver upon detection of unintentional sway . The order in which the method is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the method 300 or any 5 alternative methods. Further, one or more step blocks can be combined together to show receiving of any information. Additionally, individual blocks may be deleted from the method without departing from the scope of the subject matter described herein. Furthermore, the method(s) can be implemented in any suitable controller thereof.
10 [0045] Referring to start block of the method 300, the vehicle ignites the engine to activate or initialize the vehicle sway warning system 200.
[0046] At the step 302, the sway warning controller 208 determines turn indicator condition. If turn indicator is ON, the sway warning controller 208 does not proceed and consider this action as intentional action by the driver. In case turn 15 indicator is in OFF condition, the sway warning controller 208 proceeds to next step to receive all input values.
[0047] At step 304, the sway warning controller 208 receives steering torque value from the steering torque sensor 102 via the steering torque controller 206. The sway warning controller 208 compares the steering torque value with 20 threshold steering torque value stored in the sway warning data 211 to determine whether driver is attentive or not. If the steering torque value is less than the threshold steering torque value, the sway warning controller 208 determines that driver is in-attentive.
[0048] At step 306, the sway warning controller 208 receives vehicle velocity 25 value at instance from the vehicle velocity sensor 103. Upon comparing the vehicle velocity value with the threshold velocity value, the sway warning controller 208 may disregard the system 200 for processing when vehicle velocity is less than the threshold vehicle velocity value.
14

[0049] At step 308 if at any instance during detection of the unintentional sway before generation of warning message, the driver corrects the steering angle value and the magnitude of the current steering value after correction is less than the previous steering angle value, the sway warning controller 208 reinitialize the 5 system 200 from step 302. If not, the sway warning controller 208 proceeds to step 312.
[0050] At step 310 GPS coordinates are received from the GPS controller 205 to determine type of the path, i.e., straight or curved. If the path is straight, the method proceeds to block A. If the path is curved or not straight, the method 10 proceeds to block B.
[0051] Block A indicates method to be followed when path is straight. At step 312, the sway warning controller 208 receives the steering angle value from the steering angle sensor 102 via the steering angle controller 204. The steering angle sensor identifies movement of vehicle in lateral direction. The sway warning 15 controller 208 determines whether steering angle value is more than the threshold steering angle value or not. If yes, the sway controller proceeds to step 314. If not, the sway warning controller 208 reinitialize the method 300.
[0052] A person skilled in the art would appreciate that all inputs in the step 302 to 310 can be received at single instance instead of following the sequence. In 20 other words, the vehicle velocity, the steering torque value, the GPS coordinates, and the steering angle value can be received collectively from their respective sensor at a single instance for processing at the sway warning controller 208.
[0053] At step 314, the sway warning controller 208 calculates turn radius (r) based on the steering angle value received from the steering angle sensor 102. The 25 sway warning controller calculates the turn radius (r) by the below mentioned equations:
[0054] r = ^i^
sin a
[0055]a = steerlnaAnaleValue
Steering Angle ratio
15

5

Where α is the angle by which the wheel is turned at particular steering angle value
Steering angle ratio remains constant for a vehicle.
[0056] The sway warning controller 208 calculates the turn radius (r) and stores the calculated turn radius into the sway warning data 211.
[0057] At step 316, the sway warning controller 208 calculates lateral displacement of the vehicle based on turn radius and below mentioned equation:

L = r — y

360 ∗ velocity ∗ time
Steering Angle Value Steering Angle ratio
sin
\s \Steering Angle ratio/// /
10

Wheel Base

∗ Wheel Base

[0058] At step 318, the sway warning controller 208 compares the calculated lateral displacement (L) at each sampling time with a predefined threshold value (Lth). Upon comparing the calculated lateral displacement (L) with the predefined threshold value (Lth), the sway warning controller 208 generates warning when 15 the calculated lateral displacement (L) at any point of time is more than the predefined threshold value (Lth) at step 320. The sway warning controller 208 sends warning signal to coupled or connected audio or video or both devices.
[0059] Referring to block B which indicates the method to be followed when there is a curved path.
20 [0060] At step 322, the sway warning controller 208 determines yaw rate ‘Yr’ from the yaw rate sensor 106 via the yaw rate controller 207 of the curved path.
[0061] At step 324, the sway warning controller 208 receives prescribed yaw rate for the particular turn or curved path from the GPS controller 205 and stores the same in the sway warning data 211. The prescribed yaw rate has low threshold
16

yaw rate ‘YL’ and upper threshold yaw rate ‘YH’ for the particular curved path. The sway warning controller 208 compares the yaw rate ‘Yr’ with the prescribed yaw rate of the curved path for threshold time duration, i.e., time to complete the curved path which is based on vehicle speed. If the vehicle's yaw rate ‘Yr’ is not 5 within prescribed yaw rate at curved path, whose lower threshold is ‘YL’ and upper threshold is ‘YH’ for time greater than threshold duration, the sway warning system generates warning to driver at step 326.
[0062] The present system does not require any camera to detect unintentional sway of vehicle. Further, the present system even works efficiently on the path or 10 road where there is no lane marking or visible conditions are poor. A person skilled in the art would appreciate that the present system is efficient and effective in rural or developing countries where lane markings or lane division is not proper or effective.
[0063] It will be further appreciated that functions or structures of a plurality of 15 components or steps may be combined into a single component or step, or the functions or structures of one-step or component may be split among plural steps or components. The present invention contemplates all of these combinations. Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other 20 dimensions or geometries are possible. Plural structural components or steps can be provided by a single integrated structure or step. Alternatively, a single integrated structure or step might be divided into separate plural components or steps. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature 25 may be combined with one or more other features of other embodiments, for any given application. It will also be appreciated from the above that the fabrication of the unique structures herein and the operation thereof also constitute methods in accordance with the present invention. The present invention also encompasses intermediate and end products resulting from the practice of the methods herein.
17

The use of "comprising" or "including" also contemplates embodiments that "consist essentially of or "consist of the recited feature.
[0064] The term "vehicle" as used throughout this detailed description and in the claims refers to any moving vehicle that is capable of carrying one or more human occupants and is powered by any form of energy. The term "vehicle" is a motor vehicle which includes, but is not limited to: cars, trucks, vans, minivans, hatchback, sedan, MUVs, and SUVs.
[0065] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

We claim:

A vehicle sway warning system (200) for detecting unintentional sway and generating warning, the vehicle sway warning system (200) comprising:
sway warning controller (208) communicatively coupled with hardware interface (202) and a memory (201), the sway warning controller (208) is to:
ascertain whether turn indicator is OFF;
based on affirmative ascertainment, the sway warning controller (208):
obtain steering torque value from steering torque controller (206);
obtain vehicle velocity from vehicle velocity sensor;
obtain steering angle value from steering angle controller (204);
obtain GPS coordinates from GPS controller (205);
determine, based on the GPS coordinates, whether path is straight or curved;
calculate turn radius (r) based on the obtained steering angle;
calculate lateral displacement (L) of the vehicle at each sampling time based on the vehicle velocity, the steering angle value, wheel base, and steering angle ratio, when path is straight; and
generate a warning signal when the calculated lateral displacement (L) at any point of time is more than threshold lateral displacement (Lth).
The vehicle sway warning system (200) as claimed in claim 1, wherein the sway warning controller (208) compares the steering torque value with threshold steering torque value to determine whether driver is attentive. The vehicle sway warning system (200) as claimed in claim 1, wherein the sway warning controller (208) is to:

determine yaw rate (Yr) from yaw rate sensor (106) via yaw rate controller (207), when the path is curved;
determine whether the determined yaw rate (Yr) is not in between lower threshold (YL) and upper threshold (YH) for time greater than threshold duration; and
generate a warning signal. The vehicle sway warning system (200) as claimed in claim 1, wherein the sway warning controller (208) disregard the vehicle sway warning system (200) when the turn indicator is ON and/or driver corrects the steering angle value at any point of time.
A method (300) for detecting unintentional sway and generating warning upon unintentional sway , the method (300) comprising: ascertaining (302) whether turn indicator is OFF;
based on affirmative ascertainment, receiving ( 304, 306, 310) steering torque value, steering angle value, GPS coordinates, and vehicle velocity for each sampling time;
based on the GPS coordinates, determining (312) whether path is straight or curved;
calculating turn radius (r) (316) based on the steering angle;
calculating lateral displacement (L) (318) of the vehicle at each sampling time based on the vehicle velocity, the steering angle value, wheel base, and steering angle ratio, when path is straight; and
generating a warning signal when the calculated lateral displacement (L) at any point of time is more than threshold lateral displacement (Lth).
The method (300) as claimed in claim 6, wherein the method further
comprises:
determining (304), by steering torque controller (206) whether steering torque value is less than threshold steering torque value;

determining (306) whether vehicle velocity is more than threshold vehicle velocity; and
determining (314), by steering angle controller (204), whether steering angle value is more than steering angle threshold value.
7. The method (300) as claimed in claim 6, wherein the method comprising:
comparing (304) the steering torque value with threshold steering torque value to determine whether driver is attentive.
8. The method (300) as claimed in claim 6, wherein the method further
comprises:
calculating (324) yaw rate (Yr) from yaw rate sensor (106) via yaw rate controller (207), when the path is curved;
determining (326) whether the determined yaw rate (Yr) is not in between lower threshold (YL) and upper threshold (YH) for time greater than threshold duration; and
generate a warning signal when the determined yaw rate (Yr) is not in the lower threshold (YL) and the upper threshold (YH) for time greater than threshold duration.