Improvements to vehicle speed control

Abstract

A vehicle speed control system (16) with a lateral tilt detection system, wherein the lateral tilt detection system comprises processing means which receives terrain information from a terrain data acquisition means (185C) arranged to acquire terrain data in front of the vehicle (100) by means of one or more sensors, indicating the topography of an area extending in front of the vehicle (100), wherein the processing means (19) is configured to generate, depending on a predicted path of the vehicle (100) through the terrain extending in front of the vehicle (100), information for the predicted path of the vehicle indicating a lateral tilt angle of the predicted path corresponding to the slope of the predicted path perpendicular to the direction of travel of the vehicle (100), and wherein the vehicle speed control system is configuredthat it regulates the vehicle speed at least partially depending on the information that specifies the angle of lateral tilt generated by the tilt detection system for the anticipated path.

Description

INCORPORATED BY REFERENCE

[0001] The contents of jointly pending patent applications GB 2 507 622 A and GB 2 499 461 A are hereby incorporated by reference. The contents of US patent US 7 349 776 B2 and jointly pending patent applications WO 2013 / 124 321 A1 and WO 2014 / 139 875 A1 are hereby incorporated by reference. The contents of British patent applications GB 2 492 748 A, GB 2 492 655 A and GB 2 499 279 A and British patent GB 2 508 464 B are also hereby incorporated by reference. FIELD OF THE INVENTION

[0002] The invention relates to a system for controlling the speed of a vehicle. In particular, but not exclusively, the invention relates to a system for controlling the speed of a land-based vehicle capable of traveling in a variety of different and extreme terrain and conditions. STATE OF THE ART

[0003] In conventional vehicle speed control systems, typically referred to as cruise control systems, the vehicle's road speed, once set by the user, is maintained without further user intervention to enhance the driving experience for the user by reducing workload. The cruise control (or set speed) can be adjusted by the driver, typically by pressing a button when the vehicle has reached the desired speed. Plus and minus buttons allow for incremental speed changes while the cruise control system is set.

[0004] Once the user has selected a speed for the vehicle to maintain, the vehicle will be maintained at that speed unless the user applies the brake or, in a manual transmission vehicle, depresses the clutch pedal. The cruise control system receives a speed signal from a driveshaft speed sensor or wheel speed sensors. When the brake or clutch pedal is applied, the cruise control system is deactivated, allowing the user to override the cruise control system to change the vehicle speed without any resistance from the system. With the cruise control system engaged, if the user depresses the accelerator pedal sufficiently, the vehicle speed will increase, but as soon as the user releases their foot from the accelerator, the vehicle will coast to the preset cruising speed.

[0005] Such systems are normally only operational above a certain speed, typically around 15 to 20 km / h, and are ideal for situations where the vehicle is traveling under constant traffic conditions, particularly on trunk roads or motorways. However, in heavy traffic, where vehicle speed tends to fluctuate greatly, cruise control systems are ineffective, particularly when the systems are inoperative due to a minimum speed requirement. A minimum speed requirement is often imposed on cruise control systems to reduce the likelihood of a collision at low speeds, for example when parking. Such systems are therefore ineffective under certain driving conditions (e.g.low speed) and are set to automatically disable in situations where a user may not consider it desirable to disable the system.

[0006] More complex cruise control systems are integrated into the engine management system and sometimes include adaptive functionality that takes the distance to the vehicle ahead into account using a radar-based system. For example, the vehicle may be equipped with a forward-looking radar detection system that detects the speed and distance of the vehicle ahead and automatically maintains a safe following speed and distance without the need for user input. If the vehicle ahead brakes or another object is detected by the radar detection system, the system sends a signal to the engine or braking system to slow the vehicle accordingly and maintain a safe following distance.

[0007] Conventional cruise control systems also deactivate if a wheel slip event is detected that requires intervention by an anti-skid control (ASR) or stability control system (SCS). Accordingly, they are not well suited to maintaining vehicle progress in off-road conditions, where such situations can occur relatively frequently.

[0008] Some vehicles are designed for off-highway use, and low-speed control systems have been developed for such vehicles. In off-highway conditions, low-speed control systems allow a driver, especially a novice driver, to concentrate on activities such as steering.

[0009] Low-speed control systems suitable for off-road use may be configured to cause a vehicle to travel at a speed below the user-specified target speed depending on the roughness of the terrain over which the vehicle is traveling. Nevertheless, the present applicant has recognized that there are other circumstances besides traveling over rough terrain in which a reduced vehicle speed would be helpful to a user attempting to travel off-road.

[0010] Providing a control system to control one or more vehicle subsystems is also known. US 7,349,776 B2 discloses a vehicle control system comprising multiple subsystems, including an engine management system, a transmission control unit, a steering control unit, a brake control unit, and a suspension control unit. The subsystem control units are each operable in multiple subsystem functional or configuration modes. The subsystem control units are connected to a vehicle mode control unit, which controls the subsystem control units to enter a required functional mode to provide multiple driving modes for the vehicle. Each of the driving modes corresponds to a specific driving condition or set of specific driving conditions, and in each mode, each of the subsystems is set to the most appropriate functional mode under those conditions.These conditions are associated with various terrain types over which the vehicle may be driven, such as grass / gravel / snow, mud and ruts, rock crawling, sand, and a highway mode called "special programs off" (SPO). The vehicle mode control module may be referred to as a Terrain Response (TR) (RTM) system or control module. The drive modes may also be referred to as terrain modes, terrain response modes, or control modes.

[0011] GB 2 492 655 B discloses a control system for a motor vehicle in which the most suitable off-road mode for the prevailing terrain over which the vehicle is traveling is automatically determined by the control system. The control system then causes the vehicle to operate in the off-road mode determined to be the most suitable.

[0012] GB 2 494 528 A discloses a vehicle suspension control system with a vehicle-mounted time-of-flight camera. The vehicle-mounted time-of-flight camera is designed to provide repeated images of the scene ahead of the vehicle.

[0013] GB 2 519 024 A discloses a cruise control system for a vehicle comprising an operating unit that automatically causes a vehicle to operate according to a target speed value.

[0014] DE 10 2012 017 932 A1 relates to a method for assisting a driver when driving a vehicle off-road, wherein an environment of the vehicle is detected and a terrain profile is determined from detected environmental data, wherein at least one possible trajectory of the vehicle in the terrain profile ahead and roll angles of the vehicle occurring on the trajectory are predicted.

[0015] DE 10 2012 004 198 A1 relates to a method for assisting a driver when driving a vehicle off-road, wherein an environment of the vehicle is detected by means of at least one detection unit and a terrain profile is determined from data detected by means of the detection unit.

[0016] DE 10 2012 021 420 A1 relates to a method for assisting a driver of a motor vehicle in an off-road environment.

[0017] GB 2 471 276 A discloses a method and apparatus for terrain sensing which acquires data from at least one sensor on board a vehicle.

[0018] This invention has been designed with this in mind. Embodiments of the invention may provide an apparatus, method, or vehicle that addresses the problems identified above. Other objects and advantages of the invention will become apparent from the following description, claims, and drawings. SUMMARY OF THE INVENTION

[0019] In one aspect of the invention to be protected, there is provided a detection system for a vehicle comprising: Acquisition means for generating data indicative of the elevation of a plurality of fictitious points on the surface of a terrain in front of the vehicle with respect to a reference frame and the distance of the plurality of points from the vehicle; and Path prediction device for generating the path prediction of a vehicle in the terrain in front of the vehicle, which is based at least partly on the data generated by the detection means, wherein the system is configured to generate information for the predicted path for the vehicle indicative of the angle of lateral inclination of the predicted path, wherein the inclination of the predicted path is transverse to a direction of travel of the vehicle.

[0020] In one aspect of the invention to be protected, a vehicle control system with a roll detection system is provided, wherein the roll detection system comprises a processing means that receives terrain information indicative of the topography of an area extending in front of the vehicle from a terrain data acquisition means arranged in front of the vehicle for acquiring data relating to terrain by means of one or more sensors, wherein the processing means is configured to generate, in dependence on a predicted path of the vehicle through the terrain extending in front of the vehicle, for the predicted path of the vehicle, information indicative of a roll angle of the predicted path, wherein the inclination of the predicted path is transverse to a direction of travel of the vehicle, and wherein the cruise control system is configuredthat it regulates the vehicle speed at least partly as a function of the information indicating the angle of lateral inclination generated by the lateral inclination detection system for the anticipated path.

[0021] The terrain information may include stereoscopic images of terrain in front of the vehicle, for example, in the form of a stream of video images from respective left and right video cameras. The terrain data acquisition means may be configured to transmit the images to the terrain data processing means, which in turn may be configured to generate 3D point cloud data from the sequence of images.

[0022] Optionally, the processing device is configured to predict a path for the left and right wheels of the vehicle through the terrain and calculate the information indicating the angle of the lateral inclination of the predicted path depending on the topography of the terrain in the path of the left and right wheels.

[0023] Optionally, the processing means is configured to receive a signal indicative of the steering angle, and wherein the processing means is configured to determine the predicted path at least partially in dependence on the signal indicative of the steering angle.

[0024] Optionally, the roll sensing system is configured to generate information indicative of the roll of the predicted path relative to a reference frame that is substantially fixed with respect to the Earth by referring to data regarding the vehicle orientation relative to the reference frame.

[0025] It is noted that the data relating to the vehicle orientation relative to the reference frame may be provided by an inertial measurement unit (IMU) or other suitable means.

[0026] Optionally, the terrain information, which displays the topography of an area extending in front of the vehicle, includes a 3D point cloud.

[0027] Optionally, the processing means is configured to generate a 3D point cloud from the terrain information indicating the topography of an area extending in front of the vehicle.

[0028] Optionally, the processing means is configured to generate a height map of the terrain extending in front of the vehicle from the point cloud.

[0029] Optionally, the roll detection system is configured to divide the elevation map into cells according to the multi-level surface mapping methodology and determine the cells through which the left and right wheels of the vehicle will move as the vehicle follows the predicted path.

[0030] Optionally, the body roll detection system is configured to generate the body roll angle information at least in part based on information indicating the elevation of data points in the respective cells through which the left and right wheels of the vehicle move.

[0031] Optionally, the roll detection system is configured to identify objects in the point cloud or multi-level surface map that extend beyond the terrain in front of the vehicle and to ignore such objects when generating the information indicating the roll angle.

[0032] Optionally, the roll detection system is configured to generate information indicating the angle of roll at respective distances along the predicted path.

[0033] Optionally, the roll detection system is configured to generate information indicative of the roll angle at respective distances along the predicted path and to determine a maximum roll value along the predicted path.

[0034] Optionally, the roll detection system is configured to determine a maximum roll value over a predetermined distance along the predicted path.

[0035] Optionally, the roll detection system is configured to output a signal indicating the roll angle along the predicted path.

[0036] Optionally, the roll detection system is configured to output a signal indicating the maximum value of roll over a predetermined distance along the predicted path.

[0037] Optionally, the roll detection system is configured to output information indicating the angle of roll of the predicted path, taking into account the vehicle orientation relative to a substantially horizontal plane.

[0038] Optionally, the roll sensing system is configured to receive information indicating vehicle orientation from an inertial measurement unit (IMU).

[0039] Optionally, the lateral slope detection system also includes the terrain data acquisition means.

[0040] Optionally, the terrain data acquisition means comprises one of the following: a stereoscopic camera system, a radar-based terrain ranging system, a laser-based terrain ranging system, a structured light camera, or a monocular motion structured camera.

[0041] It should be noted that other terrain data acquisition means may be useful in some embodiments, for example, an acoustic ranging system.

[0042] The terrain data acquisition means may be configured to generate 3D point cloud information for use in determining the bank angle of the predicted path. Alternatively, the terrain data acquisition means may generate terrain data and transmit the data to the terrain data input means, wherein the system is configured to generate 3D point cloud information from the terrain data received by the terrain data input means.

[0043] Optionally, the roll detection system is configured to provide an output to a driver indicating the roll angle of the vehicle's predicted path.

[0044] Optionally, the roll detection system is configured to provide a warning to a driver depending on the information indicating the roll angle of the predicted path.

[0045] Optionally, the processing means comprises an electronic processor having an electrical input for receiving the terrain information indicating the topography of the area extending in front of the vehicle; and an electronic storage device electrically coupled to the electronic processor and storing instructions, wherein the processor is configured to access the memory device and execute the instructions stored therein such that it is operable to: Determining a predicted path of the vehicle over terrain ahead of the vehicle and generating predicted path information indicative of the roll angle of the predicted path, wherein the roll angle of the predicted path is transverse to the direction of travel of the vehicle.

[0046] Optionally, the vehicle's cruise control system is configured to control vehicle speed at least in part as a function of the maximum value of body roll along the predicted path.

[0047] Optionally, the cruise control system is configured to control the vehicle speed by limiting the vehicle speed to a predetermined maximum desired speed value depending at least in part on the information indicative of the roll angle of the predicted path.

[0048] Optionally, the predetermined maximum target speed value is determined depending at least in part on the information indicating the bank angle of the predicted path.

[0049] Optionally, the predetermined maximum target speed value is determined at least in part as a further function of the identity of a selected one of a plurality of driving modes in which the vehicle is traveling.

[0050] Optionally, in each driving mode, at least one system of several vehicle subsystems is caused to operate in one of several previously determined configuration modes of that subsystem, wherein the subsystem configuration mode is determined depending on the selected driving mode.

[0051] Optionally, the subsystems include at least a powertrain subsystem, a braking subsystem, and a suspension subsystem.

[0052] In a further aspect of the invention to be protected, a vehicle is provided comprising a body roll system or a vehicle speed control system according to any one of the preceding aspects.

[0053] In one aspect of the invention to be protected, a method for detecting the lateral inclination in front of the vehicle is provided, comprising: Receiving terrain data indicative of the topography of an area extending in front of the vehicle (100) via terrain data acquisition means (185C) arranged to acquire data relating to terrain in front of the vehicle by means of one or more sensors; in dependence on information relating to a predicted path of the vehicle (100) over the terrain extending in front of the vehicle (100), generating information for the predicted path of the vehicle (100) indicative of the roll angle of the predicted path, wherein the slope of the predicted path is transverse to a direction of travel of the vehicle (100), and controlling the vehicle speed at least in part in dependence on the information indicative of the roll angle of the predicted path and generated by the roll detection system.

[0054] Optionally, the method further comprises generating information relating to a predicted path of the vehicle (100) over the terrain extending in front of the vehicle (100).

[0055] Optionally, the method comprises generating information regarding the predicted path depending at least in part on the steering angle.

[0056] Optionally, generating information indicative of the bank of the predicted path includes generating information indicative of a maximum bank angle along the predicted path.

[0057] Optionally, generating information indicative of the roll of the predicted path includes generating information indicative of a maximum roll angle along the predicted path for a predetermined distance ahead of the vehicle.

[0058] In one aspect of the invention to be protected, a non-transitory computer-readable carrier medium is provided containing computer-readable code for controlling a vehicle to carry out the method for another aspect.

[0059] In one aspect of the invention to be protected, a computer program product is provided, executable on a processor, to implement the method according to another aspect.

[0060] In one aspect of the invention for which protection is sought, there is provided a non-transitory computer-readable medium loaded with the computer program product of another aspect.

[0061] In one aspect of the invention for which protection is sought, a processor is provided arranged to implement the method of another aspect or the computer program product of another aspect.

[0062] Within the scope of this application, it is expressly intended that the various aspects, embodiments, examples, and alternatives presented in the preceding paragraphs, in the claims, and / or in the following description and drawings, and in particular their individual features, may be considered independently of one another or in any combination. This means that all embodiments and / or features of any embodiment may be combined in any manner and / or combination, provided these features are not incompatible.The applicant reserves the right to amend any originally filed claim or to file any new claim accordingly, including the right to amend any originally filed claim to depend on and / or incorporate any feature of any other claim even though it has not been so claimed before. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] The present invention will now be described by way of example only with reference to the accompanying drawings, in which: Fig. is a schematic representation of a vehicle according to an embodiment of the invention in plan view; Fig. shows the vehicle from Fig. in side view; Fig. is a high-level schematic diagram of an embodiment of the vehicle cruise control system of the present invention, including a cruise control system and a low-speed control system; Fig. shows a steering wheel of a vehicle according to the embodiment of Fig. ; Fig. is a schematic representation of (a) a view of terrain in front of the vehicle as captured by a stereoscopic camera system, showing predicted left and right wheel tracks, and (b) a schematic representation in plan view of a height map of the terrain in front of the vehicle; and Fig. is a flowchart illustrating the operation of a vehicle according to the embodiment of Fig. represents. DETAILED DESCRIPTION

[0064] References herein to a block, such as a functional block, should be understood to include a reference to software code for performing the specified function or action, which may be an output provided in response to one or more inputs. The code may be in the form of a software routine or function called by a host computer program, or may be code that forms part of a code stream that is not a separate routine or function. Reference to the functional block is provided to simplify explanation of the operation of embodiments of the present invention.

[0065] Fig. shows a vehicle 100 according to an embodiment of the present invention. The vehicle 100 has a propulsion system 129 including an engine 121 connected to a drivetrain 130 with an automatic transmission 124. It should be noted that embodiments of the present invention are also suitable for use in vehicles with manual transmissions, continuously variable transmissions, or any other suitable transmission.

[0066] In the embodiment of Fig. The transmission 124 can be set to one of several transmission operating modes, including a park mode, a reverse mode, a neutral mode, a drive mode, or a sport mode, using a transmission mode selector dial 124S. The selector dial 124S provides an output signal to a powertrain controller 11, whereupon the powertrain controller 11 causes the transmission 124 to operate in accordance with the selected transmission mode.

[0067] The drive system 130 is arranged to drive a pair of vehicle front wheels 111, 112 through a front differential 137 and a pair of front drive shafts 118. The drive system 130 further includes an auxiliary drive system section 131 arranged to drive a pair of rear wheels 114, 115 by means of an auxiliary drive shaft or propeller shaft 132, a rear differential 135, and a pair of rear drive shafts 139.

[0068] Embodiments of the invention are suitable for use in vehicles in which the transmission is arranged to drive only one pair of front wheels or only one pair of rear wheels (ie front-wheel drive or rear-wheel drive vehicles) or in two-wheel / four-wheel drive vehicles. In the embodiment of Fig. The transmission 124 is detachably connectable to the auxiliary driveline section 131 via a power transfer unit (PTU) 131P, enabling two-wheel drive or four-wheel drive operation. Embodiments of the invention may be suitable for vehicles with more than four wheels or for vehicles in which only two wheels are driven, for example, two wheels of a three-wheeled vehicle or a four-wheeled vehicle, or a vehicle with more than four wheels.

[0069] A control system for the vehicle engine 121 includes a central controller 10, referred to as a vehicle control unit (VCU) 10, the powertrain controller 11, a brake controller 13 (an anti-lock braking system (ABS) controller), and a steering controller 170C. The ABS controller 13 is part of a braking system 22 ( Fig. ). The VCU 10 receives and outputs several different signals from various sensors and subsystems (not shown) of the vehicle. The VCU 10 includes a Low Speed ​​Progress (LSP) control system 12, which Fig. shown, a stability control system (SCS) 14, a cruise control system 16, and a hill descent control (HDC) system 12HD. The SCS 14 enhances the safety of the vehicle 100 by sensing and managing loss of traction or steering control. When a reduction in traction or steering control is detected, the SCS 14 can automatically command the ABS controller 13 to apply one or more of the vehicle's brakes to steer the vehicle 100 in the direction the user wishes to travel. In the embodiment shown, the SCS 14 is implemented by the VCU 10. In some alternative embodiments, the SCS 14 can be implemented by the ABS controller 13.

[0070] Although in Fig. Not shown in detail, the VCU 10 further includes a traction control (TC) function block. The TC function block is implemented in software code executed by a computing device of the VCU 10. The ABS controller 13 and the TC function block provide outputs indicating, for example, TC activity, ABS activity, braking interventions at individual wheels, and engine torque requests from the VCU 10 to the motor 121 in the event of a wheel slip event. Each of the aforementioned events indicates that a wheel slip event has occurred. In some embodiments, the ABS controller 13 implements the TC function block. Other vehicle subsystems, such as a roll stability control system or the like, may also be included.

[0071] As mentioned above, the vehicle 100 also includes a cruise control system 16 that is operable to automatically maintain the vehicle speed at a selected speed when the vehicle is traveling at speeds greater than 25 km / h. The cruise control system 16 is provided with a cruise control HMI (Human Machine Interface) 18 that allows the user to input a target vehicle speed into the cruise control system 16 in a known manner. In one embodiment of the invention, cruise control input controls are mounted on a steering wheel 171 ( Fig. ). The cruise control system 16 can be engaged by pressing a cruise control select button 176. When the cruise control system 16 is engaged, pressing a "set speed" control 173 sets the current value of a cruise control set speed parameter, cruise_set-speed, to the current vehicle speed. Pressing a "+" button 174 allows the cruise_set-speed value to be increased, while pressing a "-" button 175 allows the cruise_set-speed value to be decreased. There is a resume button 173R operable to control the cruise control system 16 to resume cruise control at the current cruise_set-speed value after driver override.Known highway cruise control systems incorporating the present system 16 are configured such that, when the user applies the brake or, in the case of vehicles with a manual transmission, a clutch pedal, control of the vehicle speed by the cruise control system 16 is released, and the vehicle 100 returns to a manual mode of operation, which requires accelerator or brake pedal application by a user to maintain the vehicle speed. Furthermore, the detection of a wheel slip event, such as may be triggered by a loss of traction, also has the effect of releasing control of the vehicle speed by the cruise control system 16. Cruise control by the system 16 is resumed when the driver subsequently presses the resume button 173R.

[0072] The cruise control system 16 monitors the vehicle speed, and any deviation from the target vehicle speed is automatically adjusted so that the vehicle speed is maintained at a substantially constant value, typically greater than 25 km / h. In other words, the cruise control system is ineffective at speeds below 25 km / h. The cruise control HMI 18 can also be configured to provide the user with a warning about the status of the cruise control system 16 via a visual display of the HMI 18. In the present embodiment, the cruise control system 16 is configured so that the value of cruise_set-speed can be set to any value in the range of 25-150 km / h.

[0073] The LSP control system 12 also provides a speed-based control system for the user, allowing the user to select a very low target speed at which the vehicle can continue to travel without requiring pedal inputs from the user to maintain vehicle speed. The Low Speed ​​Progress (LSP) control function is not provided by the highway cruise control system 16, which only operates at speeds above 25 km / h.

[0074] In the present embodiment, the LSP control system 12 is activated by pressing the LSP control system selection button 178 located on the steering wheel 171. The system 12 can selectively apply powertrain, traction control, and braking actions to one or more wheels of the vehicle 100, collectively or individually.

[0075] The LSP control system 12 is configured to allow a user to input a desired value of the vehicle target speed in the form of a set speed parameter, user_set-speed, via a low speed progress HMI (LSP HMI) 20 ( Fig. , Fig. ), which shares certain input keys 173-175 with the cruise control system 16 and the HDC control system 12HD. Provided the vehicle speed is within the allowable operating range of the LSP control system 12 (which, in the present embodiment, is the range of 2 to 30 km / h, although other ranges are also useful) and no other limitation on the vehicle speed exists while under control via the LSP control system 12, the LSP control system 12 controls the vehicle speed in accordance with an LSP control system set speed value, LSP_set-speed, which is substantially equal to the user_set-speed. Unlike the cruise control system 16, the LSP control system 12 is configured to operate independently of the occurrence of a traction event. That is, the LSP control system 12 does not override speed control upon detecting wheel slip.Rather, the LSP control system 12 actively controls the vehicle behavior when slippage is detected.

[0076] The LSP control HMI 20 is provided in the vehicle cabin for easy user access. The user of the vehicle 100 can communicate the desired value of user_set-speed, as mentioned above, to the LSP control system 12 via the LSP HMI 20 using the "set-speed" knob 173 and the "+" and "-" buttons 174, 175, in a similar manner to the cruise control system 16. The LSP HMI 20 also includes a visual display that can be used to provide the user with information and assistance regarding the status of the LSP control system 12.

[0077] The LSP control system 12 receives an input from the ABS controller 13 of the vehicle's braking system 22, indicating the extent to which the user has applied braking via the brake pedal 163. The LSP control system 12 also receives an input from an accelerator pedal 161, indicating the extent to which the user has depressed the accelerator pedal 161, and an input from the transmission or gearbox 124. This latter input may include signals representing, for example, the speed of an output shaft of the transmission 124, a magnitude of torque converter slip, and a gear ratio request. Other inputs to the LSP control system 12 include an input from the cruise control HMI 18 representing the status (ON / OFF) of the cruise control system 16, an input from the LSP control HMI 20, and an input from a gradient sensor 45 indicating the gradient of the driving surface over which the vehicle 100 is traveling.In the present embodiment, the gradient sensor 45 is a gyroscope sensor. In some alternative embodiments, the LSP control system 12 receives a signal indicative of a driving surface gradient from another controller, such as the ABS controller 13. The ABS controller 13 may determine a gradient based on a variety of inputs, optionally based at least in part on signals indicative of vehicle longitudinal and lateral acceleration, and a signal indicative of the vehicle reference speed (v_actual), representing the actual vehicle speed over the ground. Methods for calculating the vehicle reference speed, based, for example, on vehicle wheel speeds, are well known.For example, in some known vehicles, the vehicle reference speed may be determined as the speed of the second-slowest rotating wheel or as the average speed of all wheels. Other ways of calculating the vehicle reference speed may be useful in some embodiments, including using a camera device or a radar sensor.

[0078] The HDC system 12HD is activated by pressing button 177, which is included in the HDC system HMI 20HD and mounted on the steering wheel 171. When the HDC system 12HD is active, the system 12HD controls the braking system 22 to limit the vehicle speed to a value corresponding to an HDC set-speed parameter HDC_set-speed, which can be controlled by a user in a similar manner to the set speed of the cruise control system 16 and the LSP control system using the same control buttons 173, 173R, 174, 175. The HDC system 12HD can be operated to allow the value of HDC_set-speed to be set to any value in the range of 2–30 km / h. The HDC set-speed parameter may also be referred to as the HDC set speed.Provided that the user does not override the HDC system 12HD by pressing the accelerator pedal 161 when the HDC system 12HD is active, the HDC system 12HD controls the braking system 22 (. Fig. ) to prevent the vehicle speed from exceeding HDC_set-speed. In the present embodiment, the HDC system 12HD cannot apply positive drive torque. Rather, the HDC system 12HD is only operable to cause a negative braking torque to be applied via the braking system 22.

[0079] The VCU 10 is configured to implement a known terrain response system (TR or RTM) of the type described above, in which the VCU 10 controls settings of one or more vehicle systems or subsystems such as the powertrain control 11 depending on a selected drive mode. The drive mode can be selected by a driver via a drive mode selection dial 141S ( Fig. ). The driving modes may also be referred to as off-road modes, off-road response (TR) modes, or control modes.

[0080] In the embodiment in Fig. Four driving modes are provided: a 'road-going' driving mode, which is particularly suitable for driving on a relatively hard, smooth driving surface where there is a relatively high surface coefficient of friction between the driving surface and the vehicle's wheels; a 'sand' mode, which is suitable for driving over sandy terrain, which is described, at least in part, as having high resistance, relatively high deformability or compliance, and a relatively low surface coefficient of friction; a 'grass, gravel, or snow' (GGS) driving mode, which is suitable for driving over grass, gravel, or snow, which are quite slippery surfaces (i.e., have a relatively low surface coefficient of friction between the surface and the tires and typically lower resistance than sand); a 'rock crawl' (RC) driving mode, which is suitable for driving slowly over rocky terrain.and a "Mud and Ruts" (MR) drive mode, suitable for driving on muddy, uneven terrain. Other drive modes may be provided in addition to or instead. In the present embodiment, selector 141S also allows a user to select an "automatic drive mode selection" condition for operation, in which VCU 10 automatically selects the most appropriate drive mode, as described in more detail below. Highway mode may be referred to as a "Special Program Off" (SPO) mode in some embodiments because it corresponds to a standard drive mode and does not need to consider special factors such as a relatively low surface friction coefficient or high roughness surfaces.

[0081] To prevent or at least reduce passenger discomfort due to rapid changes in acceleration rate (jerking) when LSP control system 12 controls vehicle speed, LSP control system 12 limits the rate of change of acceleration of vehicle 100 so that the prescribed maximum value is not exceeded. The maximum allowable rate of change of acceleration or the maximum allowable jerk value is provided by the parameter LSP_J_MAX. LSP control system 12 also limits the maximum value of the acceleration rate to a value LSP_A_MAX.

[0082] The values ​​of LSP_A_MAX and LSP_J_MAX are adjusted depending, at least in part, on the TR mode and vehicle speed. In some embodiments, including the present embodiment, the values ​​for TR_mode=Sand are higher than the corresponding values ​​for TR_mode=SPO, GGS, or MR due to the higher resistance exerted on a vehicle 100 traversing sand compared to a vehicle traversing a dry asphalt highway, a grass, gravel, or snow surface, or a muddy or rutted surface.

[0083] The LSP control system 12 causes the vehicle 100 to operate in accordance with the value of LSP_set-speed.

[0084] To effect the necessary positive or negative torque at the wheels, the VCU 10 may command positive or negative torque to be applied to the vehicle wheels by the powertrain 129 and / or braking force to be applied to the vehicle wheels by the braking system 22, either or both of which may be used to implement the torque change necessary to achieve and maintain a required vehicle speed. In some embodiments, torque is applied individually to the vehicle wheels, for example, through powertrain torque vectoring, to maintain the vehicle at the required speed. Alternatively, in some embodiments, torque may be applied collectively to the wheels to maintain the required speed, for example, in vehicles with powertrains where torque vectoring is not possible.In some embodiments, powertrain controller 11 may be operable to implement torque vectoring to control an amount of torque applied to one or more wheels by controlling a powertrain component, such as a rear drive unit, front drive unit, the differential, or any other suitable component. For example, one or more components of powertrain 130 may include one or more clutches that can be actuated to allow an amount of torque applied to one or more wheels to be varied. Other implementations may also be useful.

[0085] If a drivetrain 129 comprises one or more electric machines, for example one or more drive motors and / or generators, the drivetrain controller 11 can serve to modulate the torque applied to one or more wheels in order to realize torque vector control by means of one or more electric machines.

[0086] In some embodiments, the LSP control system 12 may provide a signal wheel_slip (in Fig. (also designated 48) indicating that a wheel slip event has occurred. This signal 48 is also provided to the vehicle's highway cruise control system 16, which, in the event of a wheel slip event, initiates an override or lock-out mode of operation in the highway cruise control system 16 such that the highway cruise control system 16's automatic control of the vehicle's speed is suspended or overridden. However, the LSP control system 12 is not configured to stop or suspend operation upon receipt of the wheel_slip signal 48. Rather, the system 12 is configured to monitor and subsequently control wheel slip to reduce the driver's workload.During a slip event, the LSP control system 12 continues to compare the measured vehicle speed to the value of LSP_set-speed and continues to automatically control the torque applied to the vehicle wheels (by the driveline 129 and the braking system 22) and maintain the vehicle speed at the selected value. It should therefore be understood that the LSP control system 12 is configured differently than the cruise control system 16, for which a wheel slip event has the effect of overriding the cruise control function, requiring manual operation of the vehicle to be resumed or control by the cruise control system 16 to be resumed by pressing the resume button 173R or the speed set button 173.

[0087] The vehicle 100 is also provided with additional sensors (not shown) representative of a variety of different parameters related to vehicle motion and status. These may be inertial systems unique to the LSP or HDC control systems 12, 12HD, or parts of an occupant restraint system or any other subsystem that may provide data from sensors such as gyroscopes and / or accelerometers that may indicate vehicle body motion and provide useful inputs to the LSP and / or HDC control systems 12, 12HD. The signals from the sensors provide or calculate various driving condition indicators (also referred to as terrain indicators) that indicate the type of terrain conditions over which the vehicle 100 is traveling.

[0088] Sensors (not shown) on vehicle 100 include, but are not limited to, sensors that provide continuous sensor outputs to VCU 10, including wheel speed sensors, an ambient temperature sensor, an ambient pressure sensor, tire pressure sensors, yaw sensors for sensing the vehicle's yaw, roll, and pitch angles and rates, a vehicle speed sensor, a longitudinal acceleration sensor, an engine torque sensor (or engine torque estimator), a steering angle sensor, a steering rate sensor, a tilt sensor (or tilt estimator), a lateral acceleration sensor that may be part of SCS 14, a brake pedal position sensor, a brake pressure sensor, sensors that detect longitudinal, lateral, and vertical movement, and water detection sensors as part of the vehicle's fording assist system (not shown). In some other embodiments, only a selection of the above sensors may be employed.

[0089] The VCU 10 also receives a signal from the steering controller 170C. The steering controller 170C takes the form of an electronic power steering (ePAS) unit 170C. The steering controller 170C provides a signal to the VCU 10 indicating the steering force acting on the steerable road wheels 111, 112 of the vehicle 100. This force corresponds to the force exerted by a user on the steering wheel 171 in combination with the steering force generated by the ePAS unit 170C. The ePAS unit 170C also provides a signal indicating the steering wheel rotation position or angle.

[0090] In the present embodiment, the VCU 10 evaluates the various sensor inputs to determine the likelihood that each of the various TR modes (control modes or drive modes) is appropriate for the vehicle subsystems, with each control mode corresponding to a particular type of terrain over which the vehicle travels (e.g., mud and ruts, sand, grass / gravel / snow, as described above).

[0091] Once the user has selected vehicle operation in the automatic drive mode selection condition, the VCU 10 then selects the most appropriate of the control modes and is automatically configured to control the subsystems according to the selected mode. This aspect of the invention is described in more detail in our pending patent applications GB 2 492 748 A, GB 2 492 655 A, and GB 2 499 279 A, ​​the contents of which are incorporated herein by reference as mentioned above.

[0092] As indicated above, the type of terrain over which the vehicle is traveling (as determined by reference to the selected control mode) may also be used in the LSP control system 12 to determine an appropriate increase or decrease in vehicle speed. For example, if the user selects a user_set-speed value that is not appropriate for the type of terrain over which the vehicle is traveling, the system 12 may automatically set the LSP_set-speed value to a lower value than user_set-speed. In some cases, for example, the user-selected speed may not be achievable or appropriate for certain types of terrain, particularly in the case of uneven or rough surfaces.If the system 12 selects a set speed (a value of LSP_set-speed) that is different from the user-selected set speed user_set-speed, a visual speed limit indication is provided to the user via the LSP HMI 20 indicating that an alternative speed has been accepted.

[0093] Other arrangements may be appropriate.

[0094] In the present embodiment, the vehicle 100 is provided with a stereoscopic camera system 185C configured to generate stereo color image pairs using a pair of forward-facing color video cameras included in the system 185C. A stream of duplicate video image data is passed from the cameras to a processing unit 19 (or processing section 19), which processes the received image data and repeatedly generates a 3D point cloud dataset based on the received images. Techniques for generating 3D point cloud datasets based on stereoscopic image data are well known. Each point in the 3D point cloud dataset corresponds to a 3D coordinate of a point on a terrain surface in front of the vehicle 100 viewed by each of the forward-facing video cameras of the stereoscopic camera system 185C.

[0095] In some embodiments, non-color grayscale (black and white) cameras may be used instead of color cameras. Furthermore, in some other embodiments, a different camera arrangement, such as structured light cameras or a monocular camera with SFM (structure from motion), may be used instead of a stereoscopic camera system. In some alternative embodiments, a sensor system other than a camera system may be used, such as a LIDAR (light detection and ranging) system.

[0096] In the present embodiment, the 3D point cloud dataset is transformed such that the origin of the reference frame of the dataset is the midpoint of a line connecting the points where the two front wheels 111, 112 of the vehicle 100 touch the ground on which the vehicle 100 is traveling (also referred to herein as contact points or patches). In the present embodiment, the reference frame is defined with respect to Cartesian coordinates X, Y, Z, where X is an axis transverse to the direction of vehicle movement, i.e., along a lateral direction with respect to the vehicle 100, Y is an axis oriented in an upward direction with respect to the vehicle 100, corresponding to a substantially vertically upward direction when the vehicle 100 is parked on level ground, and Z is parallel to or coincident with a longitudinal axis of the vehicle 100, along the direction of travel of the vehicle 100.

[0097] The processing unit 19 also receives data indicating the steering angle from the ePAS unit 170C via the signal line 170L and takes this data into account when determining the predicted path.

[0098] Fig. is a schematic representation of an image of terrain in front of vehicle 100, as captured by one of the two cameras of camera system 185C. Superimposed on the image is a predicted path PP of vehicle 100 through the terrain, as determined by processing unit 19. The predicted tracks of the respective left and right wheels over the terrain are designated PPL and PPR.

[0099] The processing unit 19 then calculates a terrain elevation map populated by data points from the point cloud dataset. Fig. is a schematic representation in plan view of a height map of terrain in front of the vehicle 100. In the present embodiment, the height map is generated with respect to the vehicle's X, Y, Z axes (i.e., in the vehicle's reference frame). According to the MLS (Multi-Level Surface) mapping methodology, the height map is assumed to be composed of square cells C in the XZ plane of a predetermined size. In the present embodiment, the cells have a side length of 0.25 m, although other sizes may be useful in some embodiments.

[0100] In the present embodiment, each 3D point of the height map is assigned to a cell C according to its respective position with respect to the XZ plane. A given cell may contain points located at multiple levels or elevations, i.e., having different Y-coordinate values. The points within a given cell are grouped into one or more respective "patches" according to the Y-coordinate value, with points having a Y-coordinate within a given predetermined range of Y-coordinate values ​​being assigned to a patch corresponding to this Y-coordinate range. For example, points within a given patch are substantially coplanar, with the plane defined by these points being substantially parallel to the XZ plane.In contrast, points within the same cell corresponding to a bridge crossing the road surface would not be part of the same patch as points falling on the road surface. Each point in a given patch contains information regarding the geometry of the points falling within that patch.

[0101] It should be understood that other data structures besides MLS maps can be used, for example, voxel maps can also be used, where the purpose of the map is to reduce the number of data points.

[0102] The processing unit 19 analyzes the cells, and a cell is designated as an "obstacle" cell if the variance and range of the data points in the lowest patch of the cell exceed their respective predetermined thresholds. In some other embodiments, the mean height may be used instead. In some embodiments, a height difference (mean height) between a current cell and neighboring cells may be used to detect obstacles; that is, relatively large height steps between neighboring cells may indicate the presence of an obstacle. Cells not marked as obstacle cells may be referred to as a "horizontal patch." If a cell contains no points, it may be referred to as an "empty patch."

[0103] In addition to implementing the MLS methodology (as described above), the elevation map is refined to discard overhanging patches that are incorrectly marked as horizontal patches. An overhanging patch is a patch that is at a different elevation than a corresponding lower patch of the same cell and is consistent with the presence of an object projecting above the surface over which the vehicle 100 is traveling, such as a tree branch or a bridge under which the vehicle 100 is traveling.

[0104] Cells identified as obstacle cells are used in the calculation of body roll (described below) and typically result in high body roll angles. The high calculated values ​​typically cause the vehicle 100 to slow down as it approaches the obstacle, as described below. A driver would normally avoid such an obstacle, and the predicted path (PP), and therefore the value of the maximum body roll on the predicted path PP determined by the processing unit 19 (described in more detail below), will therefore change. In addition, cells located behind obstacles and excluded from the camera view (“obstacle shadows” or “shadow cells”) are identified and ignored. This is because they could interfere with the correct calculation of the roll.

[0105] The processing unit 19 then determines the cells in front of the vehicle 100 through which the front tires of the vehicle 100 are expected to travel, i.e., cells through which the predicted tracks PPL and PPR of the left and right front wheels 111, 112 are likely to travel, including cells marked as obstacle cells. The processing unit 19 uses a known value of the track length T of the vehicle 100 (i.e., the distance between the centers of the wheels of a given axle, which is shorter than the overall vehicle width W of the vehicle 100) to determine the predicted tracks PLL and PPR. The processing unit 19 calculates a roll value as a ratio between (1) the difference in the vertical height values ​​between the respective left and right cells, corresponding to the position of the front wheels of the vehicle 100, and (2) the track length T of the vehicle 100.In the present embodiment, the processing unit 19 calculates slip slope values ​​with respect to successive pairs of left and right cells over a predetermined distance D ahead of the vehicle 100 along the predicted path PP, as shown in FIG. Fig. shown. In the present embodiment, the predetermined distance D is approximately 15 m, although other values ​​may be useful in some embodiments.

[0106] The processing unit 19 then corrects the roll values ​​taking into account the orientation of the vehicle at a given time. The processing unit 19 receives information indicating a vehicle orientation with respect to an Earth reference frame Xe, Ye, Ze, where Xe is a horizontal axis through the center of an imaginary line connecting the contact patches of the front wheels 111 and 112 of the vehicle 100 and is a projection of the X-axis onto a horizontal plane through the center, Ye is a vertical axis through the center, and Ze is a horizontal axis through the center, orthogonal to the Xe and Ye axes. The processing unit 19 receives a signal indicating a vehicle orientation with respect to the Xe-Ze plane from an inertial measurement unit (IMU) 23.

[0107] The processing unit 19 then transforms the roll values ​​(calculated in the vehicle reference frame X, Y, Z) to the Earth reference frame Xe, Ye, Ze. Subsequently, the processing unit 19 determines the maximum roll angle over the predetermined distance D.

[0108] In some embodiments, processing unit 19 determines the probable path (or toe) of front wheels 111 and 112 and the corresponding probable path of rear wheels 114 and 115, which may differ during cornering, and calculates the roll values ​​for the front and rear wheel pairs accordingly. In the present embodiment, processing unit 19 performs this step by determining the identity of the cells in front of vehicle 100 on which the respective left and right front and rear wheels 111, 112, 114, and 115 of vehicle 100 may be located at a given time as the vehicle moves along predicted path PP, at least in part using a value of the wheelbase length, where L is the distance between the frontmost and rearmost axles, in addition to the toe length T.In other words, the roll value is calculated for each pair of cells that the left and right front wheels simultaneously pass along the predicted path PP. In some embodiments, the processing unit 19 uses this information to calculate a cross-axis rotation value when the direction of roll differs between the front and rear axles. The processing unit 19 may additionally calculate the rate of change of the roll value or angle.

[0109] In some alternative embodiments, the roll value may be calculated at predetermined intervals along the predicted path PP, such as intervals of approximately 0.1 m in the XZ plane, 0.125 m (corresponding to half the side of a given cell in the XZ plane), or any other suitable interval.

[0110] The roll angle is calculated as the inverse tangent of the ratio of the difference between the mean elevation values ​​and the above-mentioned track length T.

[0111] The processing unit 19 outputs a value of the maximum calculated roll angle to the LSP control system 12. In addition, the VCU 10 can display the maximum calculated value of the roll angle to a driver via the instrument cluster 195.

[0112] In some embodiments, the processing unit 19 transforms the point cloud dataset from the vehicle reference frame X, Y, Z to the Earth reference frame Xe, Ye, Ze to correct the vehicle orientation before applying the MLS methodology and splitting the point cloud points in a particular cell into patches. In other embodiments, the vehicle orientation may be taken into account at a different time point in the determination of the roll angle.

[0113] As mentioned above, a value of the lateral tilt angle relative to the earth's axes is output to the LSP control system 12 via the signal 12S ( Fig. ). The LSP control system 12 uses the roll angle value from a lookup table to calculate a maximum allowable value of LSP_set-speed and LSP_set-speed_max. The value of LSP_set-speed_max is calculated depending, at least in part, on the roll angle value and the identity of the TR mode in which the vehicle 100 is operating. In the present embodiment, the LSP control system 12 considers other indicators of the maximum allowable value of LSP_set-speed, including terrain surface roughness, which are also used by the VCU 10 to determine the most appropriate drive mode (TR mode) when operating under automatic drive mode selection conditions.

[0114] Specifically, in the present embodiment, the LSP control system 12 includes a lookup table for the roll angle versus LSP_set_speed_max. In the present embodiment, but not in all embodiments, multiple lookup tables are provided, one for each travel mode (TR mode). The maximum roll angle over the next 15 m of terrain in front of the vehicle 100 is calculated, and the corresponding value of LSP_set_speed_max is taken from the lookup table. A parameter LSP_set_speed_max_ss (which is the maximum allowable value of LSP_set_speed based on the calculated roll angle) is then used by the LSP control system 12, which distinguishes between different values ​​of LSP_set_speed_max based on various factors, including the surface roughness of the terrain, as mentioned above.The LSP control system 12 takes the smallest value of the maximum LSP set speed and limits the value of LSP_set-speed accordingly.

[0115] The maximum value of LSP_set-speed may be higher in certain TR modes, such as Highway mode, for a given value of the absolute slope angle of the terrain in front of the vehicle 100. This is because the terrain during Highway TR operation is likely to be smoother and less uneven with respect to the left and right wheel tracks PPL, PPR of the vehicle 100, resulting in less change in the relative suspension linkage (in the form of rolling or bouncing) as the vehicle 100 traverses the terrain compared to off-road modes such as MR or RC.

[0116] Fig. illustrates how the determination of the lateral inclination angle is carried out.

[0117] In step S101, the processing unit 19 receives a stream of image data from the stereoscopic camera system 185C.

[0118] In step S103, the processing unit 19 calculates the 3D point cloud dataset based on the most recently received stereoscopic image pair consisting of the stream of image data. In some embodiments, averaging of one or more respective left and right image frames may be performed to generate a "smoothed" left and right image frame, respectively, thereby reducing image noise. Other noise reduction techniques may be applied in addition to or instead.

[0119] In step S105, the point cloud dataset from the processing unit 19 is converted to the vehicle reference frame X, Y, Z from the reference frame of the camera system 185C. In the present embodiment, the camera system 185C is mounted in the upper region of the windshield of the vehicle 100.

[0120] In step S107, the processing unit 19 generates a height map with respect to the vehicle frame.

[0121] In step S109, the processing unit 19 divides the height map into cells and groups data points in each cell into one or more patches.

[0122] In step S111, the processing unit 19 identifies all patches of each cell corresponding to objects that overhang the predicted path and ignores these patches for subsequent calculations related to terrain slope.

[0123] In step S113, the processing unit 19 identifies shadow cells in the elevation map and ignores them for subsequent calculations related to terrain slope.

[0124] In step S115, the processing unit 19 calculates the wheel tracks PPL and PPR for the left and right front wheels, respectively.

[0125] In step S117, the processing unit 19 identifies cells C through which the left and right front wheels 111 and 112 of the vehicle 100 will pass when the vehicle wheels move along the predicted tracks PPL and PPR up to a distance D in front of the vehicle 100. The processing unit 19 calculates the roll angle relative to the earth's axes Xe, Ye, Ze for each consecutive pair of cells C through which the left and right wheels 111 and 112 will pass, respectively.

[0126] In step S119, the processing unit 19 determines the maximum roll angle along the predicted path based on the calculations in step S117.

[0127] At S121, the processing unit 19 outputs the value of the maximum roll angle calculated in step S119 to the LSP control system 19 via the signal 12S. The processing unit 19 also outputs the maximum roll angle to the user via a visual display on the instrument cluster 195.

[0128] In some alternative embodiments, the LSP control system 12 is configured to set the value of LSP_set-speed_max to a value that depends on the current value of LSP_set-speed and the value of the roll angle in front of the vehicle 100, as indicated by the signal 12S. Other arrangements may be suitable in some embodiments. For example, the value of LSP_set-speed may be set to a value that additionally or alternatively depends on a rate of change of the roll angle along the predicted path.If the rate of change of the body roll angle is relatively high, indicating a rough surface or a relatively short portion of the predicted path that passes over a pothole, rut, boulder, or other obstacle, the value of LSP_set-speed can be decreased or further reduced to account for possible sway or roll of the vehicle while traveling over that portion of the predicted path.

[0129] Some embodiments of the present invention enable more comfortable operation of the vehicle 100 when traversing terrain with a side slope. This is due, at least in part, to a reduction in driver workload when operating with the active LSP control system 12. This is because a driver does not need to manually decrease the value of user_set-speed to reduce the vehicle speed when approaching terrain with a relatively steep side slope. Rather, the vehicle 100 assumes that the vehicle 100 will be traversing terrain with a side slope and reduces the vehicle speed accordingly.

[0130] It is to be understood that the above-described embodiments are given only as examples and are not intended to limit the invention, the scope of which is defined in the appended claims.

[0131] Throughout the description and claims of this specification, the words "comprise" and "include" and variations of the words such as "comprising" or "comprises" mean "including, but not limited to," and are not intended to exclude (and do not exclude) other parts, additives, components, numbers, and steps.

[0132] In the description and claims of this patent specification, the singular includes the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification should be understood to encompass both plural and singular usage, unless the context otherwise requires.

[0133] Functions, integers, properties, compounds, chemical moieties, or groups described in connection with a particular aspect, embodiment, or example of the invention are to be understood as applicable to any other aspect, embodiment, and example described hereinbelow unless they are incompatible therewith.

Claims

[1] A vehicle speed control system (16) with a side slope detection system, wherein the side slope detection system comprises processing means that receives terrain information indicating the topography of an area extending in front of the vehicle (100) from a terrain data acquisition means (185C) that is arranged to acquire data relating to terrain in front of the vehicle (100) by means of one or more sensors, wherein the processing means (19) is configured to generate, in dependence on a predicted path of the vehicle (100) through the terrain extending in front of the vehicle (100), information for the predicted path of the vehicle that indicates a side slope angle of the predicted path that corresponds to the inclination of the predicted path transverse to the direction of travel of the vehicle (100), and wherein the vehicle speed control system is configuredthat it regulates the vehicle speed at least partly as a function of the information indicating the angle of lateral inclination generated by the lateral inclination detection system for the anticipated path. [2] A vehicle speed control system (16) according to claim 1, wherein the terrain information comprises data points indicating the elevation of the terrain at a plurality of positions ahead of the vehicle (100), the processing means (19) being configured to provide information on the roll of the predicted path by identifying data points corresponding to the terrain over which the left and right wheels of the vehicle (100) will respectively travel, and by calculating the roll at least in part by reference to the elevation difference between the ground under the left and the ground under the right wheels over which the vehicle (100) will travel. [3] A vehicle speed control system (16) according to claim 1 or 2, wherein the processing means (19) is configured to predict a path for the left and right wheels of the vehicle (100) through the terrain through which the vehicle (100) will travel, respectively, and calculate information indicative of the angle of bank of the predicted path depending on the topography of the terrain in the path of the left and right wheels. [4] A vehicle speed control system (16) according to the preceding claims, wherein the processing means (19) is configured to receive a signal indicative of the steering angle, and wherein the processing means (19) is configured to determine the predicted path at least partly in dependence on the signal indicative of the steering angle. [5] A vehicle speed control system (16) according to any preceding claim, configured to generate information indicative of the roll of the predicted path relative to a reference frame that is substantially fixed with respect to the earth by reference to data relating to the vehicle orientation relative to the reference frame. [6] A vehicle speed control system (16) according to the preceding claims, wherein the terrain information indicating the topography of an area extending in front of the vehicle (100) comprises a 3D point cloud. [7] A vehicle speed control system (16) according to the preceding claims, wherein the processing means (19) is configured to generate a 3D point cloud from the terrain information indicating the topography of an area extending in front of the vehicle (100). [8] A vehicle speed control system (16) according to claims 6 and 7, wherein the processing means (19) is configured to generate from the point cloud a height map of the terrain extending in front of the vehicle (100). [9] A vehicle speed control system (16) according to claim 8, configured to divide the elevation map into cells according to the multi-level surface mapping methodology and to determine the cells through which the left and right wheels of the vehicle (100) will move when the vehicle (100) follows the predicted path. [10] A vehicle speed control system (16) according to claim 9, configured to generate the information indicative of the roll angle in dependence at least in part on information indicative of the height of data points in the respective cells through which the left and right wheels of the vehicle (100) move, respectively. [11] A vehicle speed control system (16) according to claims 6 to 10, configured to identify in the point cloud, or in the described multi-level surface map, objects that project beyond the terrain in front of the vehicle (100) and to ignore such objects when generating the information indicative of the angle of roll. [12] A vehicle speed control system (16) according to any preceding claim, configured to generate information indicative of the roll angle at respective distances along the predicted path. [13] A vehicle speed control system (16) according to any preceding claim, configured to generate information indicative of the roll angle at respective distances along the predicted path and to determine a maximum roll value along the predicted path. [14] A vehicle speed control system (16) according to claim 11, configured to determine a maximum value of roll over a predetermined distance along the predicted path. [15] A vehicle speed control system (16) according to any preceding claim, configured to output a signal indicative of the roll angle along the predicted path. [16] A vehicle speed control system (16) according to claim 14 or other claims dependent thereon, configured to output a signal indicative of the maximum value of body roll over a predetermined distance along the predicted path. [17] A vehicle speed control system (16) according to any preceding claim, configured to output information indicative of the angle of bank of the predicted path taking into account the vehicle orientation relative to a substantially horizontal plane. [18] A vehicle speed control system (16) according to claim 17, configured to receive information indicative of vehicle orientation from an inertial measurement unit. [19] A vehicle speed control system (16) according to the preceding claims, wherein the terrain data acquisition means (185C) comprises one of the following: a stereoscopic camera system (185C), a radar-based terrain ranging system, a laser-based terrain ranging system, a structured light camera, or a monocular motion structured camera. [20] A vehicle speed control system (16) according to the preceding claims, configured to provide an output to a driver indicative of the roll angle of the predicted path of the vehicle (100). [21] A vehicle speed control system (16) according to any preceding claim, configured to provide a warning to a driver in dependence upon the information indicative of the roll angle of the predicted path. [22] A vehicle speed control system (16) according to any one of the preceding claims, wherein the processing means (19) comprises an electronic processor having an electrical input for receiving the terrain information indicative of the topography of the area extending in front of the vehicle (100), and an electronic storage device electrically coupled to the electronic processor and having instructions stored therein, the processor being configured to access the storage device and execute the instructions stored therein such that it is operable to: Determining a predicted path of the vehicle (100) over terrain in front of the vehicle (100) and generating information for the predicted path of the vehicle (100) that indicates the bank angle of the predicted path, wherein the bank of the predicted path is transverse to the direction of travel of the vehicle (100). [23] A vehicle speed control system (16) according to claim 13 or claims dependent thereon, configured to control the vehicle speed at least partly in dependence on the maximum value of the roll along the predicted path. [24] A vehicle speed control system (16) according to any preceding claim, configured to control the vehicle speed by limiting the vehicle speed to a predetermined maximum desired speed value depending at least in part on information indicative of the bank angle of the predicted path. [25] A vehicle speed control system (16) according to claim 24, wherein the predetermined maximum desired speed value is determined at least in part in dependence upon the information indicative of the bank angle of the predicted path. [26] A vehicle speed control system (16) according to claim 25, wherein the predetermined maximum desired speed value is determined at least in part as a further function of the identity of a selected one of a plurality of driving modes in which the vehicle (100) is traveling. [27] A vehicle speed control system (16) according to claim 26, wherein in each driving mode, at least one of a plurality of vehicle subsystems is caused to operate in one of a plurality of predetermined configuration modes of that subsystem, the subsystem configuration mode being determined in dependence on the selected driving mode. [28] A vehicle speed control system (16) according to claim 26 or 27, wherein the subsystems comprise at least a powertrain subsystem, a braking subsystem and a suspension subsystem. [29] A vehicle (100) having a vehicle speed control system (16) according to the preceding claims. [30] A method for controlling vehicle speed, the method comprising detecting a roll in front of the vehicle (100), wherein detecting the roll in front of the vehicle comprises: Receiving terrain data indicative of the topography of an area extending in front of the vehicle (100) via terrain data acquisition means arranged to acquire data relating to terrain in front of the vehicle (100) by means of one or more sensors; in dependence on information relating to a predicted path of the vehicle (100) over the terrain extending in front of the vehicle (100), generating information for the predicted path of the vehicle (100) indicating the lateral inclination angle of the predicted path, wherein the inclination of the predicted path is transverse to a direction of travel of the vehicle (100), the method further comprises controlling the vehicle speed depending at least in part on the information indicative of the lateral gradient of the predicted path. [31] A method according to claim 30, further comprising generating information relating to a predicted path of the vehicle (100) over the terrain extending in front of the vehicle (100). [32] A method according to claim 31, comprising generating information relating to a predicted path depending at least in part on the steering angle. [33] A method according to claims 30 to 32, wherein generating information indicative of the bank of the predicted path comprises generating information indicative of the maximum bank angle along the predicted path. [34] A method according to claims 30 to 33, wherein generating information indicative of the lateral slope of the predicted path comprises generating information indicative of the maximum slope angle along the predicted path for a predetermined distance ahead of the vehicle (100). [35] A computer program product executable on a processor to implement the method of any one of claims 30 to 34. [36] A non-transitory computer-readable medium carrying computer-readable code which, when executed, causes a vehicle (100) to perform the method of claims 30 to 34. [37] A processor arranged to implement the method of claims 30 to 34 or the computer program product of claim 35.

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