EP4182193A1

EP4182193A1 - Control system for failsafe operation of a vehicle

Info

Publication number: EP4182193A1
Application number: EP21758800.3A
Authority: EP
Inventors: Mohan Shanmugam; Sharma PRAVEEN KUMAR; Naveen NATARAJAN KRISHNAKUMAR; Venkatesh Govindan; Kakkanattu Mathews Winney; Sudhaharan THIYAGARAJAN
Original assignee: TVS Motor Co Ltd
Current assignee: TVS Motor Co Ltd
Priority date: 2020-07-16
Filing date: 2021-07-15
Publication date: 2023-05-24
Also published as: WO2022013892A1; CN115803236A

Abstract

The present invention related to a control system and a method of controlling vehicle operating state. The system and method of controlling is designed such that the rider to select ABS ride-mode to only first failsafe predetermined mode from any other mode during his continuous driving based on State Parameter Value (SPV). Accordingly, it improves the safety of the user because user can quickly change only to a first failsafe predetermined mode without paying attention on the display. Therefore, it is not necessary for user to get distracted by changing his view or attention from the road to the display when vehicle is on move.

Description

CONTROL SYSTEM FOR FAILSAFE OPERATION OF A VEHICLE

TECHNICAL FIELD

[0001] The present subject matter relates to a vehicle . More particularly, to a control system for a failsafe operation and a method of controlling said vehicle operating state. BACKGROUND

[0002] Typically, antilock braking system is configured to take full advantage of the available tire pavement friction capability without locking the wheels and losing vehicle control. Antilock brake systems operate by monitoring each wheel for impending lock up. When wheel lock up is anticipated the system reduces brake pressure on the wheel. When the wheel begins to roll freely again, the system reapplies braking pressure. The system constantly monitors each wheel and readjusts the brake pressure until the wheel torque is no longer sufficient to lock the wheel. Generally, the antilock brake system is controlled by an onboard control unit.

[0003] The above information disclosed in this background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

BRIEF DESCRIPTION OF THE DRAWINGS [0004] The detailed description is described with reference to an exemplary embodiment with the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.

[0005] Figure 1 illustrates a control system for fail safe operation of a vehicle as per embodiment, in accordance with one example of the present subject matter. [0006] Figure 2 illustrates a flow chart depicting ride mode changing strategy as per an embodiment, in accordance with one example of the present subject matter. DETAILED DESCRIPTION

[0007] Various features and embodiments of the present subject matter here will be discernible from the following further description thereof, set out hereunder.

[0008] In recent years, anti-lock braking system (hereinafter “ABS”) i.e. anti-skid brake system has become part of a motor vehicle standard configuration. It improves safety of a user by effectively preventing the phenomenon’s such as wheel lockup etc. However, the ABS is critically traded-off between brake performance and stability control. The stability control includes wheel locking prevention or rear wheel lift off protection (hereinafter “RLP”). Further, it is a great challenge to provide same degree of safety on various road and environmental conditions while using single strategy of ABS control as a common solution across various usage conditions as well as various range of products.

[0009] To address above safety issue, the progress in the development of braking systems lead to improved version of ABS known as “Ride-mode ABS”. The Ride mode ABS is different from a base control version ABS or conventional ABS. Because ride-mode ABS is provided with various ride modes controlled by an ABS control unit to use under various road and weather conditions. In other words, ride-mode ABS allows user to tailor virtually every aspect of their motor vehicle brake performance based on road conditions and their driving preference. Therefore, the ride-mode ABS is intended to improve road safety while facilitating selection of optimal mode. The ride modes include various modes like street /urban mode, rain mode, and sports mode which are more suitable at various road and environmental conditions.

[00010] In order to select the appropriate modes by the user an ABS mode change switch and an indicator is provided on a vehicle dashboard. The ride-mode ABS enables the user to switch from one mode to any other mode even while continuously driving the motor vehicle. However, in related art, while changing modes the user needs to look at the vehicle dashboard to confirm his action taken on ABS mode- change while continuous driving. This phenomenon can cause a distraction to or a diversion of the user. The distraction to or a diversion of user even for less than a second, from his continuous attention on driving, continuously watching traffic and taking appropriate controls accordingly, can lead to accidents. This accident risk possibilities are very high at high speed and for low skill level users. Because usage of ABS mode change options while continuous driving requires users possessing high skill levels for simultaneously driving (i.e. navigation, traffic monitor, and controlling) and doing ABS mode-change (i.e. switching and looking /watching dashboard more particularly mode indicator, and confirming the ABS mode change whether it is proper as per rider’ s intention) . But the same option may lead to high risk for other users those have less skill level.

[00011] Further, if the user chooses any wrong ABS mode which is not appropriate to that particular road and environmental conditions can lead to risk for safety. This problem can be appreciated from the fact that a premium bike loaded with multiple features may be driven by a not so skilled rider. The risk for safety is there as long as user is driving in that wrong ABS ride-mode on the particular road and environmental conditions. Because characteristics of ABS control strategy with any particular control mode is a compromise for results or effects on other road and environmental conditions. More specifically, if the street /urban mode is abase mode for ABS control strategy then another mode called, rain-mode will compromise braking feel and performance on any good road or high friction surface with good environmental conditions. This is because, when rain-mode is selected, the priority is given to stability i.e. wheel lock control rather than braking feel and performance. Similarly, the sport mode will compromise stability control in terms of wheel locking /RLP control. In other words, ABS behavior in a sport-mode is opposite to that of the rain-mode. [00012] However, to address the above-mentioned problem due to improper mode switching, one of the ways is to perform ABS ride-mode selection when the motor vehicle is at stand-still condition. But this can lead to poor driving comfort and inconvenience during continuous driving. Precisely, when user is continuously driving in busy traffic at intercity express ways if there is sudden rain then user needs to switch the ABS mode to rain-mode from current mode to ensure at least some minimum level safety without any risk. But in reality, it may not be always feasible to suddenly slow down and stop the vehicle to change the mode, which halting itself could be against safety norms. For instance, if the vehicle is moving in the midst of fast-moving covey of -vehicles, it is not advisable to suddenly slow down and stop, which can cause rear- end collision with vehicle coming from behind. While the above problems are in general applicable to any multi wheeled vehicle, the problem is further aggravated for a two wheeled saddle type vehicle where the rider is already performing the complex task of balancing the vehicle and therefore distracting the rider can be fatal.

[00013] Therefore, there is a need for improved control system for ABS system which is failsafe even with a novice rider and which overcomes all the above problems and other problems of known art.

[00014] To this end, it is an object of the present invention to provide a control system strategy for ABS ride-mode selection which allows modes switching by the user as well as ensure both road safety as well user’s comfort.

[00015] It is another object of the present invention to provide a system and a method which promotes more confident riding in the user.

[00016] To this end, the present invention provides a control system configured with a strategy for ABS ride-mode selection where the system is so configured to allow user to select only a predetermined failsafe ABS ride-mode under predetermined conditions based on vehicle State Parameter Value (SPV). Further, the system is designed to allow the user to change to any riding mode, based on predetermined vehicle State Parameter Value (SPV).

[00017] Furthermore, as per another embodiment, the user can change to any riding mode when the vehicle is stopped or in standstill condition.

[00018] Moreover, as per another embodiment of the present system architecture, the user can select or change ABS ride-mode to a predetermined ABS mode during continuous riding based on a vehicle State Parameter Value (SPV) which is more suitable for sudden change in road and environmental conditions when the vehicle is running. Further, it does not require any attention of user, from road, traffic and continuous normal driving course, onto the display for checking and confirming the mode selection unlike the conventional ABS ride mode. The vehicle State Parameter Value (SPV) includes vehicle speed. [00019] In addition to above, as per an aspect of the present invention, when the vehicle is in running condition above a predetermined speed, any change in mode selection would only allow change to predetermined failsafe mode.

[00020] According to the present subject matter to attain the above-mentioned objectives, a first characteristic of the present invention is the control system which is configured with a method of controlling a vehicle operating state. The control system for fail safe operation of a vehicle comprising of a mode selection interface to receive input ride mode selection from a user; one or more vehicle mode processing unit to process a mode change request information received by means of said input ride mode selection; one or more sensors configured to provide a first set of parameters to said one or more vehicle mode processing unit; said vehicle mode processing unit is configured to detect a current vehicle state parameter and compare with a predetermined vehicle state parameter to generate a predetermined output command; and one or more ride mode control hardware, said one or more ride mode control hardware is configured to be activated based on said predetermined output command from said vehicle mode processing unit.

[00021] In addition to the first characteristic, the second characteristic of the present invention is control system for fail safe operation of a vehicle, wherein said predetermined output command includes first determination output command based on which ride mode is changed from current mode to user requested ride mode. [00022] In addition to the first characteristic, the third characteristic of the present invention is control system for fail safe operation of a vehicle, wherein said predetermined output command includes second determination output command based on which ride mode is changed from current mode to first predetermined failsafe mode. [00023] In addition to the first characteristic and the third characteristic, the fourth characteristic of the present invention is control system for fail safe operation of a vehicle, wherein said predetermined output command includes second determination output command if said current ride mode is said first predetermined failsafe ride mode, then retaining said current ride mode.

[00024] According to the present subject matter to attain the above-mentioned objectives, a fifth characteristic of the present invention is the method comprising receiving a ride mode change input, by a vehicle mode processing unit; receiving a current State Parameter Value (SPV) from one or more speed sensors; comparing said State Parameter Value (SPV) with a predetermined State Parameter Value (SPV), by said processing unit; determining first if said current State Parameter Value (SPV) is lesser than said predetermined State Parameter Value (SPV), wherein based upon said first criteria, changing a ride mode from a current ride mode to one or more requested ride modes which may be different from said current ride mode; and determining if said current State Parameter Value (SPV) is greater than said predetermined State Parameter Value (SPV), wherein based upon a second determination, changing said ride mode from said current ride mode to a first predetermined failsafe ride mode. [00025] In addition to the fifth characteristic, a sixth characteristic of the present invention is the system and method of controlling the vehicle operating state, wherein said method comprising retaining said current ride mode if said current ride mode is said first predetermined failsafe ride mode.

[00026] In addition to the fifth characteristic, a seventh characteristic of the present invention is the system and method of controlling of the vehicle operating state, wherein said first predetermined failsafe ride mode includes rain mode.

[00027] In addition to the fifth characteristic, an eighth characteristic of the present invention is the system and method of controlling the vehicle operating state, wherein said vehicle state parameter value includes one or more of a speed signal, tilt-sensor signal, GPS position signal, acceleration signal etc.

[00028] In addition to the fifth characteristic, a ninth characteristic of the present invention is the system and method of controlling the vehicle operating state, wherein said predetermined vehicle operating state includes predetermined vehicle speed, said vehicle speed ranges from 1 to 15 kmph.

[00029] In addition to the fifth characteristic, an tenth characteristic of the present invention is the system and method of controlling the vehicle operating state, wherein said change to the first predetermined failsafe ride mode from any current mode when the vehicle is in running condition, at a predetermined speed, can be achieved by actuating a ride mode change interface. [00030] In addition to the fifth characteristic, an eleventh characteristic of the present invention is the system and method of controlling the vehicle operating state, wherein said change to the first predetermined failsafe ride mode from any current mode when the vehicle is in running condition, at a predetermined speed, is configured to be achieved by actuating a dedicated safe ABS mode selection interface.

[00031] In addition to the fifth characteristic, a twelfth characteristic of the present invention is the system and method of controlling the vehicle operating state, wherein said change to the first predetermined failsafe ride mode from any current mode when the vehicle is in running condition, at a predetermined speed, can be achieved through voice-over commands.

[00032] In addition to the fifth characteristic, a thirteenth characteristic of the present invention is the system and method of controlling the vehicle operating state, wherein said change to the first predetermined failsafe ride mode from any current mode when the vehicle is in running condition, at a predetermined speed, can be achieved by utilizing any existing switches with a predetermined actuation strategy including a long press.

[00033] The present subject matter is further described with reference to accompanying figures. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.

[00034] The foregoing disclosure is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. As such, it is contemplated that various alternate embodiments and/or modifications to the present disclosure, whether explicitly described or implied herein, are possible in light of the disclosure. Having thus described embodiments of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the present disclosure. Thus, the present disclosure is limited only by the claims. [00035] In the foregoing specification, the disclosure has been described with reference to specific embodiments. However, as one skilled in the art will appreciate, various embodiments disclosed herein can be modified or otherwise implemented in various other ways without departing from the spirit and scope of the disclosure. Accordingly, this description is to be considered as illustrative and is for the purpose of teaching those skilled in the art the manner of making and using various embodiments of the disclosure . It is to be understood that the forms of disclosure herein shown and described are to be taken as representative embodiments. Equivalent elements, materials, processes or steps may be substituted for those representatively illustrated and described herein. Moreover, certain features of the disclosure may be utilized independently of the use of other features, all as would be apparent to one skilled in the art after having the benefit of this description of the disclosure. Expressions such as “including”, “comprising”, “incorporating”, “consisting of’, “have”, “is” used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.

[00036] Further, various embodiments disclosed herein are to be taken in the illustrative and explanatory sense, and should in no way be construed as limiting of the present disclosure. All joinder references (e.g., attached, affixed, coupled, connected, etc.) are only used to aid the reader's understanding of the present disclosure, and may not create limitations, particularly as to the position, orientation, or use of the systems and/or methods disclosed herein. Therefore, joinder references, if any, are to be construed broadly. Moreover, such joinder references do not necessarily infer that two elements are directly connected to each other.

[00037] Additionally, all numerical terms, such as, but not limited to, “first”, “second”, “third”, “primary”, “secondary”, “main” or any other ordinary and/or numerical terms, should also be taken only as identifiers, to assist the reader's understanding of the various elements, embodiments, variations and/or modifications of the present disclosure, and may not create any limitations, particularly as to the order, or preference, of any element, embodiment, variation and/or modification relative to, or over, another element, embodiment, variation and/or modification. [00038] It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application. Additionally, any signal hatches in the drawings/figures should be considered only as exemplary, and not limiting, unless otherwise specifically specified.

[00039] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[00040] Figure 1 illustrates a control system (101) for a failsafe operation. The control system (101) comprising of a mode selection interface (102), one or more vehicle mode processing unit (103) and one or more ride control hardware (104). The mode selection interface (102) is configured to receive ride mode selection input (102A) from a user. The inputs request from the mode selection interface (102) are further processed by the vehicle mode processing unit (103). The vehicle mode processing unit (103) includes an Electronic Control Unit (ECU). The vehicle mode processing unit (103) is configured to detect a current vehicle state parameter and compare with a predetermined vehicle state parameter to generate a predetermined output command. The predetermined output command includes first determination output command based on which ride mode is changed from current mode to user requested ride mode. Further, the predetermined output command includes second determination output command based on which ride mode is changed from current mode to first predetermined failsafe mode. However, if said current ride mode is said first predetermined failsafe ride mode, then retaining said current ride mode. The vehicle mode processing unit (103) configured to receive additional inputs from one or more sensors (103 A). The sensors (103A) provide first set of parameters or additional check parameters to the vehicle mode processing unit (103). Furthermore, the predetermined output command from the vehicle mode processing unit (103) is transmitted to the one or more ride mode control hardware (104). e.g. ABS unit to be activated in a permissible failsafe ride mode of the vehicle. [00041] Figure 2 illustrates a flow chart depicting methodology of ride mode changing strategy, in accordance with one example implementation of the present subject matter wherein the vehicle state parameter value includes vehicle speed. The process starts with step (S101) where a vehicle mode processing unit (103) (as shown in fig. 1) receives a ride mode change input from the user. Subsequent to step (S101), the vehicle mode processing unit (103) (as shown in fig. 1) receives input from one or more vehicle state parameter e.g. speed sensors (103A) (as shown in fig. 1) to calculate current speed of the vehicle (not shown) (S102). Further, step (S103) comprises comparing said current vehicle state parameter value i.e. speed value with a predetermined vehicle state parameter i.e. predetermined vehicle speed. At step (S103), the vehicle mode processing unit (103) (as shown in fig. 1) determines first if said current state parameter value i.e. current vehicle speed value is lesser than said predetermined state parameter value i.e. predetermined vehicle speed. Based upon said first determination if the current vehicle state parameter value i.e. current vehicle speed is less than predetermined vehicle state parameter value i.e. predetermined vehicle speed, the processing unit at step (S104) changes a ride mode from a current ride mode to one or more requested ride modes which is different from said current ride mode. However, if said current vehicle state parameter value i.e. current vehicle speed value is greater than said predetermined vehicle state parameter value i.e. predetermined vehicle speed, then at step (S105) the vehicle mode processing unit (103) (as shown in fig. 1) determines whether the current mode is a first determined failsafe mode. If the current mode is not the first predetermined failsafe mode, then in step (S106) the vehicle ride mode processing unit changes said ride mode from said current ride mode to a first predetermined failsafe mode. At step (S105) if vehicle mode processing unit (103) (as shown in fig. 1) determines that said current ride mode is said first predetermined failsafe ride mode then at step (S107) the vehicle mode processing unit (103) (as shown in fig. 1) retains said current ride mode. In other words, if the vehicle (not shown) is in first predetermined failsafe mode and vehicle speed is greater than predetermined speed then the vehicle remains in first predetermined failsafe ride mode. Therefore, when the vehicle is moving at a speed greater than predetermined vehicle speed, the user can change only to first predetermined failsafe mode from any mode. The predetermined vehicle operating state includes predetermined vehicle speed, said vehicle speed ranges from 1 to 15 kmph. As per an alternate embodiment, the predetermined vehicle State Parameter Value (SPV) can be one or more of a tilt-sensor signal, GPS position signal, acceleration signal etc.

[00042] As per one implementation, the first predetermined failsafe mode comprises of safe mode or default mode which is configured to provide enhanced safety. The safe mode includes a rain mode.

[00043] In an embodiment, the change to the first predetermined failsafe mode from any current mode when the vehicle is in running condition, at a predetermined speed, can be achieved by actuating the ride mode switch (not shown) or a touch screen interface or a voice command. In another embodiment, a dedicated safe ABS mode switch (not shown) can be provided. Alternatively, in another embodiment, the changeover to the first predetermined mode can also be achieved through voice-over commands. Further, in alternate embodiment, the changeover can be achieved by utilizing any existing switches (not shown) with a different actuation strategy, for example, a long press of a switch. Thus, ensuring that the safety problem associated with selection of ride mode during vehicle running condition is eliminated.

[00044] In addition to above, as per embodiment, when the vehicle is in standstill condition, the user can select any mode from the current mode.

[00045] According to above architecture, the primary efficacy of the present invention is that the system and method of controlling vehicle operating state improves the safety of the user because user can quickly change only to a first predetermined failsafe mode without paying attention on the vehicle dashboard. Therefore, it is not necessary for user to get distracted by changing his view or attention from the road to the dashboard when vehicle is on move.

[00046] According to above architecture, the primary efficacy of the present invention is that system and method of controlling vehicle operating state improves the user’s comfort and thereby safety since the user need not stop the vehicle to change to first predetermined mode from any other mode.

[00047] According to above architecture, the primary efficacy of the present invention is that the system and method of controlling vehicle operating state gives flexibility to the user to select any mode when vehicle is moving at the predetermined speed or in stand still condition.

[00048] According to above architecture, the primary efficacy of the present invention is that the system and method of controlling vehicle operating state eliminates any wrong selection of mode control by the user while driving continuously on road. Because user can quickly change only to a first predetermined failsafe mode when riding at high speed. Therefore, the system is made fool-proof even while changing mode without stopping the vehicle on any sudden change in wet or bad roads. [00049] The above-described embodiments, and particularly any “preferred” embodiments, are possible examples of implementations and merely set forth for a clear understanding of the principles of the invention. Therefore, the invention is equally applicable to motor vehicles including multi wheeled vehicles equipped with ABS. As per one implementation said vehicle comprising of a two wheeled saddle type vehicle configured to have control system and method of controlling vehicle operating state as described in detail description of the present application. Further, in above described embodiments, “Riding”, “Ride mode” should not be read to limit the scope of invention to two wheeled or three wheeled vehicles similar to “trike”. It will be apparent to those skilled in the art that changes in form, connection, and detail may be made therein without departing from the spirit and scope of the invention.

Claims

We Claim:

1. A control system (101) for fail safe operation of a vehicle comprising of a mode selection interface (102) to receive input ride mode selection (102A) from a user; one or more vehicle mode processing unit (103) to process a mode change request information received by means of said input ride mode selection

(102A); one or more sensors (103A) configured to provide a first set of parameters to said one or more vehicle mode processing unit (103); said vehicle mode processing unit (103) is configured to detect a current vehicle state parameter and compare with a predetermined vehicle state parameter to generate a predetermined output command; and one or more ride mode control hardware (104), said one or more ride mode control hardware (104) is configured to be activated based on said predetermined output command from said vehicle mode processing unit (103).

2. The control system (101) for fail safe operation of a vehicle as claimed in claim 1, wherein said predetermined output command includes first determination output command based on which ride mode is changed from current mode to user requested ride mode.

3. The control system (101) for fail safe operation of a vehicle as claimed in claim 1, wherein said predetermined output command includes second determination output command based on which ride mode is changed from current mode to first predetermined failsafe mode.

4. The control system (101) for fail safe operation of a vehicle as claimed in claim 3, wherein said predetermined output command includes second determination output command if said current ride mode is said first predetermined failsafe ride mode, then retaining said current ride mode.

5. A method of controlling a vehicle operating state, said method comprising: at step (S101) receiving a ride mode change input, by a vehicle mode processing unit (103); at step (S102) receiving a vehicle state parameter value from one or more speed sensors; at step (SI 03) comparing said current vehicle state parameter value with a predetermined vehicle state parameter value, by said processing unit; determining as a first determination whether said current vehicle state parameter value is lesser than said predetermined vehicle state parameter value , wherein based upon said first determination , at step (S104) changing a ride mode from a current ride mode to one or more user requested ride modes which is different from said current ride mode (S104); and at step (S105) determining as a second determination whether said current vehicle state parameter value is greater than said predetermined vehicle state parameter value, wherein based upon said second determination, at step (S106) changing said ride mode from said current ride mode to a first predetermined failsafe ride mode.

6. The method of controlling vehicle operating state as claimed in claim 5, wherein said method comprising at step (S107) retaining said current ride mode if said current ride mode is said first predetermined failsafe ride mode.

7. The method of controlling vehicle operating state as claimed in claim 5, wherein said first predetermined failsafe ride mode includes rain mode.

8. The method of controlling vehicle operating state as claimed in claim 5, wherein said vehicle state parameter value includes one or more of a speed signal, tilt-sensor signal, GPS position signal, acceleration signal etc.

9. The method of controlling vehicle operating state as claimed in claim 5, wherein said predetermined vehicle state parameter value includes speed signal ranges from 1 to 15 kmph.

10. The method of controlling vehicle operating state as claimed in claim 5, wherein said change to the first predetermined failsafe ride mode from any current mode when the vehicle is in running condition, at a predetermined speed, can be achieved by actuating a ride mode change interface.

11. The method of controlling vehicle operating state as claimed in claim 5, wherein said change to the first predetermined failsafe ride mode from any current mode when the vehicle is in running condition, at a predetermined speed, is configured to be achieved by actuating a dedicated safe ABS mode selection interface.

12. The method of controlling vehicle operating state as claimed in claim 5, wherein said change to the first predetermined failsafe ride mode from any current mode when the vehicle is in running condition, at a predetermined speed, can be achieved through voice-over commands.

13. The method of controlling vehicle operating state as claimed in claim 5, wherein said change to the first predetermined failsafe ride mode from any current mode when the vehicle is in running condition, at a predetermined speed, can be achieved by utilizing any existing switches with a predetermined actuation strategy including a long press.

14. A vehicle comprising of a two wheeled saddle type vehicle, said vehicle configured to have control system and method of controlling vehicle operating state as claimed in any of the preceding claims.