Vehicle control system

Abstract

A control system for controlling vehicle speed to navigate a speed bump comprises controllers configured to receive speed bump information from a geographic information system indicative of a position

Description

TECHNICAL FIELD The present disclosure relates to a control system for a vehicle. Aspects of the invention relate to a control system, to a computer program product, to a computer-readable medium, to a vehicle, and to a method of operating the vehicle. BACKGROUND Modern vehicles are known to feature Advanced Driver Assistance Systems (ADAS) and Autonomous Driving (AD) systems for assisting a driver in a variety of driving scenarios. Such systems provide partial or fully automatic control of the vehicle. For example, AD systems are known for controlling the steering and / or speed of the vehicle, at least when driving on certain roadways and / or in certain geographically bound areas. A challenge with autonomous driving control relates to the perceived driving experience. In particular, it is a challenge to ensure the comfort of the vehicle occupants when navigating a vehicle through traffic calming measures such as speed bumps, which are difficult to identify, and account for, in real-time. Existing AD systems therefore fail to provide adequate speed compensation for such traffic calming measures, leading to passenger discomfort and possible vehicle damage during autonomous driving. It is an aim of the present invention to address one or more of the disadvantages associated with the prior art. SUMMARY OF THE INVENTION According to an aspect of the invention, there is provided a control system for controlling vehicle speed to navigate a speed bump. The control system comprises one or more controllers configured to execute machine-readable instructions to: receive speed bump information for one or more speed bumps from a geographic information system, the speed bump information being indicative of a respective position in a co-ordinate system of each speed bump; receive a route path from a path planning system of the vehicle, the route path comprising a series of path passing points defining a route of the vehicle, in the coordinate system, towards a target destination; inspect successive intervals of the route path, defined between respective pairs of the path passing points, for an intersection with the indicated position of at least one of the one or more speed bumps; and when a first speed bump in the route path is detected by the inspection: determine the proximity of the vehicle, along the route path, to the first speed bump; and output a control signal for controlling the vehicle speed whilst approaching the first speed bump based on: (i) the determined proximity; (ii) a current vehicle speed; and (iii) a speed limit associated with the first speed bump. In this manner, the control system can identify the next speed bump in the path of the vehicle, and determine its relative proximity to the vehicle along the route path, in a computationally efficient manner. Once the proximity to the first speed bump has been determined, the control system determines and outputs a control signal for controlling the vehicle speed to satisfy a speed limit associated with the first speed bump, enabling a timely vehicle response and ensuring that the speed bump is navigated at a comfortable speed. In an example, the speed bump information may further comprise information indicative of a speed limit associated with each speed bump. For example, the speed limits may therefore be predetermined for respective speed bumps and stored in the geographic information system. Optionally, the speed bump information may further comprise information indicative of a classification of each speed bump as one of a plurality of speed bump classifications. Each speed bump classification may be associated with a respective speed limit. The geographic information system may therefore store predetermined speed bump classifications for each speed bump and respective speed limits for each speed bump classification, enabling consistent and effective speed control for different types of speed bumps. For example, the plurality of speed bump classifications may comprise: a speed bump, a speed hump, and a speed table. In an example, the control system may be configured to determine the speed limit associated with the first speed bump based on the speed bump information received for that speed bump. In an example, outputting the control signal for controlling the vehicle speed may further comprise: determining a threshold distance from the first speed bump based on: (i) a reference deceleration parameter, and (ii) a difference between the current vehicle speed and the speed limit for the first speed bump; and outputting the control signal for controlling the vehicle speed according to the reference deceleration parameter when the determined proximity reaches the threshold distance. The reference deceleration parameter may, for example, be a deceleration limit for the vehicle. In this manner, the speed control system is able to provide a controlled and consistent deceleration pattern for traversing different speed bumps, producing a human-like driving experience. Optionally, the control system may be configured to receive a high-definition map from the geographic information system. The control system may be configured to determine the speed bump information from the high-definition map. For example, the high-definition map may comprise one or more annotated speed bumps. The high-definition map therefore stores predetermined speed bump information, allowing the control system to readily determine the position of speed bumps intersecting the route path. Optionally, the high-definition map may further comprise one or more roads divided into a plurality of road segments. The series of path passing points may, for example, correspond to successive endpoints of the plurality of road segments arranged along the route path. In this manner, the path planning system may readily determine the route path based, at least in part, on the HD map of the geographic information system and determine path passing points that correspond to start or end points of respective road segments. The colocation of such point support the computational efficiency of determining the position of speed bumps intersecting the route path. In an example, the control system may further comprise the path planning system. The path planning system may be configured to determine the route path based on the received high-definition map. This allows for efficient generation of the route path and a high level of correspondence between the route path and the high-definition map for identifying the location of speed bumps in the route path in a computationally efficient manner. Optionally, the one or more controllers may be configured to receive a current vehicle position from a navigation system of the vehicle. The path planning system may, for example, be configured to determine the route path based on the high-definition map and the current vehicle position. That is the path planning system may locate the current vehicle position on the high-definition map and identify successive road segments defining a route path towards the target destination. Optionally, the control system may be configured to iteratively inspect a set number of successive intervals of the route path for the speed bump intersection. In this manner, the control system may inspect the set number of intervals and determine, in that iteration, that no speed bump is currently in the inspected portion of the route path. The vehicle can therefore proceed at an ordinary driving speed and the control system will proceed to inspect another set of intervals during the next iteration. This allows for computationally efficient identification of the next speed bump in the route path. Each set of inspected intervals may be partly or fully overlapping with the set of intervals inspected during the previous iteration. For example, the control system may be configured to iteratively inspect the set number of successive intervals of the route path at a prescribed frequency, and / or each iteration may be triggered in dependence on detecting one or more trigger conditions relating to the vehicle position and / or the route path. For example, successive iterations may be triggered by respective updates to the route path, and / or when the vehicle reaches the end of an inspected interval. In an example, the control system may be configured to inspect one or more successive intervals of the route path for a second speed bump in the route path, more distal than the first speed bump. The second speed bump may be detected where the indicated position of another one of the one or more speed bumps is intersected by a respective one of the inspected one or more intervals. When a second speed bump is detected in the route path, the one or more controllers may be configured to output the control signal for controlling the vehicle speed based on a proximity of the first speed bump to the second speed bump. In this manner, the control system provides a human-like driving experience when navigating pairs of speed bumps in close proximity to one another, mitigating unnecessary accelerations and / or decelerations between the first and second speed bumps. According to another aspect of the invention, there is provided a method for controlling a vehicle to navigate a speed bump. The method comprises: receiving speed bump information for one or more speed bumps from a geographic information system, the speed bump information being indicative of a respective position in a co-ordinate system of each speed bump; receiving a route path from a path planning system of the vehicle, the route path comprising a series of path passing points defining a route of the vehicle, in the coordinate system, towards a target destination; inspecting successive intervals of the route path, defined between respective pairs of the path passing points, for an intersection with the indicated position of at least one of the one or more speed bumps; and when a first speed bump in the route path is detected by the inspection: determining the proximity of the vehicle, along the route path, to the first speed bump; and outputting a control signal for controlling the vehicle speed whilst approaching the first speed bump based on: (i) the determined proximity; (ii) a current vehicle speed; and (iii) a speed limit for the first speed bump. According to a further aspect of the invention, there is provided a computer program product, comprising computer readable instructions which, when the program is executed by one or more processors cause the one or more processors to perform the method described in a previous aspect of the invention. According to yet another aspect of the invention, there is provided a computer readable medium comprising instructions which, when executed by a computer, cause the computer to perform the steps of the method described in a previous aspect of the invention. According to a further aspect of the invention there is provided a vehicle comprising: a computer program as described in a previous aspect of the invention, a computer readable medium as described in another previous aspect of the invention, and / or a control system as described in a further one of the previous aspects of the invention. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a schematic illustration of an exemplary vehicle in accordance with an embodiment of the invention; Figure 2 shows a schematic illustration of an exemplary control system, in accordance with an embodiment of the invention, of the vehicle shown in Figure 1; Figures 3a, 3b, and 3c illustrate exemplary speed bump classifications used by the control system shown in Figure 2; Figure 4 schematically illustrates an exemplary route path determined by the control system shown in Figure 2; Figure 5 illustrates an exemplary vehicle speed control profile for controlling the speed of the vehicle, shown in Figure 1, as it approaches a speed bump; Figures 6 illustrates an exemplary method, according to an embodiment of the invention, of controlling the vehicle, shown in Figure 1, to navigate a speed bump; Figure 7 illustrates exemplary sub-steps, in accordance with an embodiment of the invention, of the method shown in Figure 6; and Figure 8 illustrates another exemplary method, in accordance with an embodiment of the invention, of controlling the vehicle, shown in Figure 1, to navigate speed bumps. DETAILED DESCRIPTION Embodiments of the present invention relate to control systems and corresponding methods for controlling the speed of a vehicle as the vehicle navigates traffic calming measures, such as speed bumps, whilst travelling along a route path to a target destination. The control system is configured to automatically control the vehicle speed, whilst approaching such speed bumps, so as to provide a comfortable, and human-like, driving experience. For this purpose, the control system is configured to receive a series of path passing points, defining a route of the vehicle towards the target destination, along with speed bump information, indicating the position of one or more speed bumps on respective roadways. For example, the speed bump information may be derived from a high-definition map, including annotated speed bump features and roadway information. For example, the HD map may divide the roadways into discrete road segments, with respective identifiers for each segment. The control system is therefore able to readily locate the speed bumps and the path passing points in a common co-ordinate system, for example with the intervals between adjacent path passing points of the route path being defined by, or otherwise corresponding to, respective end points of the road segments in the HD map. Advantageously, the control system uses such information to identify the next speed bump in the path of the vehicle, and determines its relative proximity to the vehicle along the route path, in a computationally efficient manner. In particular, the control system is configured to identify a first or next speed bump in the route path by inspecting successive intervals (extending between adjacent path passing points) for an intersection with at least one of the speed bumps. That is, determining whether the vehicle trajectory, between adjacent path passing points, intersects the indicated position of one of the speed bumps. For example, the control system may be configured to analyse or inspect a set number of intervals extending ahead of the vehicle to check for a speed bump lying in the path of the vehicle, and iteratively repeats such checks as the vehicle travels towards the target destination, identifying relevant speed bumps as they are approached. When a first speed bump is detected in the route path, the control system can determine its relative proximity to the vehicle, along the route path, in an efficient manner (e.g. by adding the intervening interval distances together). The control system can therefore make an accurate determination of the proximity of the vehicle to the next speed bump, allowing for a timely vehicle response. Accordingly, once the proximity to the first speed bump has been determined, the control system determines and outputs a control signal for controlling the vehicle speed to satisfy a speed limit associated with the first speed bump. For example, a speed bump may be associated with a speed limit of approximately 25 mph for comfortable driving. It is envisaged that embodiments of the invention will therefore lead to a computationally efficient method of controlling the vehicle to detect and navigate speed bumps in the path of the vehicle, allowing for a timely response and comfortable driving experience, whilst also reducing costs and improving robustness in AD systems. Embodiments of the invention shall now be discussed in more detail with reference to Figures 1 to 8. Figure 1 shows a plan view of an exemplary vehicle 1 in accordance with an embodiment of the invention. In this example, the vehicle 1 takes the form of a passenger car. However, this example is not intended to be limiting on the scope of the invention and, in other examples, the vehicle may take various other forms, such as a bus, or a truck, amongst other passenger or commercial vehicles. The vehicle 1 features one or more Advanced Driver Assistance Systems (ADAS) I Autonomous Driving (AD) systems for assisting the driver in a variety of driving scenarios, and includes a control system 2 for controlling the vehicle speed whilst navigating speed bumps in the route path to a target destination. The target destination may be provided by a user input, for example via interaction with a human-machine interface device of the vehicle 1. An exemplary control system 2, in accordance with an embodiment of the present invention, shall now be discussed in more detail with additional reference to Figure 2. As shown in Figure 2, the control system 2 includes a drive system 4, a geographic information system 6, a path planning system 8, a navigation system 10, and a speed control system 12, in this example. That is, the control system 2 is shown to include five functional elements, units, modules, or sub-systems in Figure 2. Each of these units, modules or sub-systems may be provided, at least in part, by suitable software running on any suitable computing substrate using conventional or customer processors and memory. Some or all of the units or modules may use a common computing substrate (for example, they may run on the same server) or separate substrates, or different combinations of the modules may be distributed between multiple computing devices. The example architecture of the control system 2 is not intended to be limiting on the scope of the invention though and, in other examples, it shall be appreciated that the architecture may take other suitable forms. The drive system 4 is configured to control the driving speed of the vehicle 1, and receives one or more control signals from the speed control system 12 to adjust the speed for speed bumps in the path of the vehicle 1, providing a comfortable, and human-like, deceleration and driving speed. For this purpose, the drive system 4 may include a transmission system 13, a braking system 14, and a propulsion system 15, as shown in the example in Figure 2. It shall be appreciated that each of the transmission system 13, the braking system 14 and the propulsion system 15 may take different forms in dependence on the configuration of the vehicle 1. For example, the vehicle 1 may be a battery electric vehicle and the propulsion system 15 may comprise one or more electric machines for generating drive torque and / or motor braking. In another example, the vehicle 1 may take the form of a hybrid electrical vehicle and the propulsion system 15 may comprise one or more electric machines and an internal combustion engine or, in a further example, the vehicle 1 may take the form of an internal combustion vehicle and the propulsion system 15 may comprise a spark ignition or combustion ignition internal combustion engine. The configuration of the drive system 4 is not intended to be particularly limiting on the scope of the invention though and the drive system 4 may control the speed of the vehicle in accordance with the received control signals using any combination of torque, friction and / or drag generating devices. Although not shown in Figure 2, it shall be appreciated that the vehicle 1 may also include a steering system, such as an electrically controlled steering system, configured to control the driving direction of the vehicle 1. For example, the vehicle 1 may include a steering system that is configured to control the driving direction based on a route path received from the path planning system 8 in order to provide autonomous steering. Such a steering system is not described in detail here to avoid obscuring the invention but it shall be appreciated that the steering system may take any suitable form known in the art and may, for example, include: a steering mechanism configured to control the driving direction of the vehicle 1; a sensor system configured to detect the driving direction of the vehicle 1; an actuation system configured to control the steering system; and a controller configured to control the actuation system based on the determined route path. In this manner, the vehicle 1 is configured to follow the route path determined by the path planning system 8, with the vehicle trajectory being controlled by the steering system and the vehicle speed being controlled by the drive system 4, for example according to control signals received from the speed control system 12. The geographic information system 6, navigation system 8, and path planning system 10 are collectively configured to provide suitable information for: (i) locating the vehicle 1 in spatial relation to a target destination, (ii) determining a route path leading towards the target destination, and (iii) determining the proximity of the vehicle 1 to the closest speed bump on the route path. The geographic information system 6 includes or otherwise has access to geographically referenced information, including speed bump information, for use in understanding the driving environment of the vehicle 1 and controlling the vehicle speed as the vehicle 1 follows a route path. The geographically referenced information may correspond to a particular mapped area, for example. The speed bump information is indicative of the position of one or more speed bumps on respective roadways, e.g. the position of such speed bump(s) on a local or global reference co-ordinate system, and the speed bump information may therefore be provided in various forms within the scope of the invention. For example, the geographic information system 6 may include or have access to a database of predetermined speed bump information for a geographic area, and / or a map, such as a high-definition map, annotated with such speed bump information. For context, a high-definition (HD) map is known in the art to be a relatively detailed and accurate map (e.g. precise to the nearest centimetre), which is primarily used in the field of autonomous driving and contains details that are not normally present on traditional maps. HD maps may be captured by combining data from an array of sources and sensors, such as LiDARs, radars, digital cameras, GPS, and aerial imagery. HD maps typically include map elements such as road shape, road marking, traffic signs, barriers and traffic calming devices, such as speed bumps, providing discretely labelled I annotated features. The geographic information system 6 of the vehicle 1 may therefore include or access a HD map that includes annotated speed bump information and annotated road segment information for a mapped area. The annotated speed bump information indicates the position of any speed bumps in the mapped area and may further include additional data such as a classification of each speed bump and / or an associated speed limit for each speed bump. The road segment information may include identifiers for respective road segments of each roadway. It shall be appreciated that the HD map may be preprogrammed by the manufacture or downloaded from, and / or otherwise accessed via, a third-party client server, for example. The speed bumps are typically classified into individual categories according to their respective shape and size. For example, the speed bump classifications may include: a speed bump, a speed hump, and / or a speed table. Each speed bump classification is intended to have a different traffic calming effect and may therefore be associated with a respective speed limit for navigating said speed bump. As shall be described in more detail, an associated speed bump classification may therefore be further provided to the speed control system 12 for enhanced control of the vehicle speed when approaching a particular speed bump. By way of example, Figures 3a, 3b, and 3c illustrate respective speed bump classifications that may be included in the speed bump information of the geographic information system 6. Figure 3a schematically illustrates an exemplary speed bump 28. The speed bump 28 is a raised pavement feature with a rounded dome, starting and ending at road level with the highest point in the centre. In general, the speed bump 28 may be approximately four to six inches in height and one to three feet in length across the road. The speed bump 28 is mostly used in private residential developments and parking lots and is designed to be approached at very low speeds. Typically, the speed bump 28 is associated with a speed limit less than or equal to 10 mph to ensure vehicles pass over the bump safely and without causing damage or undue discomfort to the passengers. If driven over too quickly, speed bumps 28 can be jarring and potentially harmful to both the vehicle and its occupants. Figure 3b schematically illustrates an exemplary speed hump 30. The speed hump 30 has a broader dome with a more gradual rise than the speed bump 28, allowing the hump 30 to be traversed at a greater speed, and may be associated with a speed limit that is greater than 10 mph but generally less than or equal to 25 mph. Generally, a speed hump 30 may be approximately three to four inches in height and ten to twelve feet in length across the road. The speed hump 30 is mostly used on residential streets and is designed to be approached at a low speed. Figure 3c schematically illustrates an exemplary speed table 32. The speed table 32 has a gentle incline ramp, an elevated flat top section, and a gentle decline ramp. The vehicle ascends the incline ramp and reaches the flat top section where the entire wheelbase of the vehicle is accommodated, allowing the vehicle to level off at the top section before descending on the decline ramp. The speed table 32 is used on more frequently travelled residential streets and is designed to be approached at a greater average speed. For example, the speed table 32 may be associated with a speed limit that is greater than 25 mph but generally less than or equal to 30 mph. In general, speed tables 32 may be approximately three to four inches in height and twenty-two feet in length across the road. Hence, each speed bump classification may be associated with a respective speed limit and the speed bump information may therefore indicate a geographic location of each speed bump, in addition to the speedbump classification in order to inform the control of the driving speed. The navigation system 10 is configured to determine vehicle pose information, such that the vehicle 1 can be located in spatial relation to the indicated positions of the speed bumps and the target destination. For example, the navigation system 10 may be configured to monitor the trajectory of the vehicle by determining vehicle pose information, including the current vehicle position and orientation in a reference co-ordinate system, which may correspond to the referenced area of the geographical information system 6. That is, the navigation system 10 may be configured to locate the vehicle position and orientation in a coordinate system corresponding to the HD map, enabling the vehicle 1 to be located in the mapped area. For this purpose, the navigation system 10 may take the form of, or otherwise include, a global navigation satellite system (GNSS) and / or a visual simultaneous localisation and mapping (VSLAM) system, for example. The path planning system 8 is an ADAS configured to determine the route path that the vehicle 1 follows to the target destination during autonomous driving. That is, the path planning system 8 determines a series of path passing points located in spatial relation to the vehicle 1, determining the trajectory of the vehicle 1 at each point and collectively defining the route path along which the vehicle 1 is steered as the vehicle 1 drives towards the target destination. It shall be appreciated that the path planning system 8 may determine the route path for the vehicle 1 to follow based on vehicle pose and target destination information determined by the navigation system 10, and / or using geographic information, such as the HD map, provided by the geographical information system 6. Accordingly, it shall be appreciated that the geographic information system 6, navigation system 10, and path planning system 8 may interact or otherwise collectively define an overall system for determining the route path, including a series of path passing points located in spatial relation to the vehicle 1, as well as the indicated positions of the speed bumps, and the target destination, in a common co-ordinate system. Adjacent path passing points may therefore correspond to start and end points of successive road segments of the HD map. By way of example, Figure 4 illustrates a portion of an exemplary route path 200 determined by the path planning system 8. The route path 200 describes the trajectory of the vehicle 1 in the mapped area, leading from a starting point to the target destination. As shown in Figure 4, the vehicle 1 is travelling along the route path 200 in a direction of travel illustrated by an arrow 26. The route path 200 includes a plurality of path passing points 24 defined in the co-ordinate system of the HD map, collectively defining the route 200 of the vehicle 1 towards the target destination. In this example, the path passing points 24 are arranged ahead of the vehicle 1, extending around a plurality of roadway bends, and over speed bumps 20, indicated by the geographic information system 6. The path passing points 24 are determined based, at least in part, on information from the HD map and, in this example, the path passing points 24 correspond to respective start / end points of successive road segments 22 of the HD map. Accordingly, successive intervals between adjacent pairs of the path passing points 24 correspond to respective road segments 22 of the HD map. In other examples, the path passing points 24 may, for example, be arranged at regular intervals along such road segments 22 instead though and this example is not intended to be particularly limiting on the scope of the invention. Path planning systems, such as GPS and VSLAM systems, configured for determining such a route path, are well-known in the art and are not described in more detail here to avoid obscuring the invention. Nonetheless, more information can be found in the discussion about localisation and mapping techniques in “An Overview to Visual Odometry and Visual SLAM: Applications to Mobile Robotics” by K. Yousif, A. Bab-Hadiashar and R. Hoseinnezhad as published in Intelligent Industrial Systems 1, 289-311 (2015), for example. Along the route path 200, the vehicle 1 will therefore encounter various traffic calming devices, such as the speed bumps 20, and the speed control system 12 is configured to control the vehicle speed accordingly in order to navigate such speed bumps 20. For this purpose, the speed control system 12 includes one or more controllers configured to: (i) inspect successive intervals of the route path 200 to identify the nearest speed bump 20, (ii) determine the proximity of the vehicle 1, along the route path 200, to the identified speed bump 20, and (iii) output one or more control signals to the drive system 4 for controlling the vehicle speed accordingly as the vehicle 1 travels along the route 200 and over the identified speed bump 20. The speed control system 12 may therefore include one or more schemes, rules, or algorithms, for processing successive intervals of the route path 200 and checking each interval for an intersection with the indicated positions of the speed bumps 20. For example, where successive intervals of the route path 200 correspond to successive road segments 22 of the HD map, the speed control system 12 may be configured to check the corresponding road segments 22, in sequence, for the presence or absence of an annotated speed bump in the HD map. In another example, where the speed bump information is obtained separately form the HD map, the speed control system 12 may be configured to perform such checks based solely on the indicated positions of the speed bumps. For example, for each interval, the speed control system 12 may be configured to determine the trajectory of the vehicle 1 from one path passing point 24 to the next path passing point 24, and determine whether the indicated trajectory intersects the indicated position of one of the speed bumps 20. It shall be appreciated that a subset of speed bumps 20 may be considered for this inspection and the subset may, for example, be confined to a particular proximity to the vehicle 1. In an example, the speed control system 12 may be configured to iteratively check for speed bumps 20 in the route path 200 and inspect a set number of intervals during each iteration. For example, the speed control system 12 may be configured to inspect up to four successive intervals during each iteration. If a speed bump 20 is detected in the inspected intervals, the speed control system 12 may proceed to determine the proximity of the vehicle 1, along the route path 200, to the detected speed bump 20, and adjust the vehicle speed accordingly. However, if no speed bumps are detected in the inspected intervals, the speed control system 12 may proceed to repeat the assessment during the next iteration, e.g. upon reaching the next path passing point 24. Once the nearest speed bump 20 is detected, the control system 12 is configured to determine the proximity of the vehicle 1, along the route path 200, to that speed bump 20, and the control system 12 include one or more suitable schemes, rules, or algorithms, for this purpose. It is not intended for the control system 12 to be particularly limited in this respect but the control system 12 may, for example, be configured to determine the proximity by summing together the interval distances of the intervals extending between the vehicle 1 and the detected speed bump 20. Thereafter, in order to comfortably navigate the detected speed bump 20, the speed control system 12 is configured to output control signal(s) to the drive system 4 to cause the vehicle to decelerate to a respective speed limit associated with the detected speed bump 20. For example, as discussed above, the speed limit may be indicated by the speed bump information, such as the speed bump classification, and the control system 12 may determine the associated speed limit based thereon. In order to control the vehicle deceleration, the speed control system 12 may be configured to determine a vehicle speed control profile based on the current vehicle speed, the speed limit of the detected speed bump 20, and the proximity of the vehicle 1, along the route path 200, to the identified speed bump 20. For example, the determined vehicle speed control profile may include a threshold proximity to the speed bump 20 to be used as a trigger to start decelerating the vehicle according to a reference deceleration parameter, such as a deceleration limit. Alternatively, the vehicle speed control profile may, for example, include a target speed for respective path passing points 24 leading towards and over the detected speed bump 20. The vehicle speed control profile may therefore cause the drive system to steadily reduce the vehicle speed upon reaching a path passing point 24 within the threshold proximity of the detected speed bump 20. The vehicle speed control profile may, for example, be determined using one or more reference deceleration parameters and / or one or more predetermined deceleration profiles. Such information may be stored in a memory of the speed control system 12, for example in a look-up table, and the speed control system 12 may select a reference deceleration parameter and / or a predetermined deceleration profile based on the difference between the current vehicle speed and the speed limit associated with the detected speed bump, for example. Figure 5 illustrates an exemplary vehicle speed control profile 300 that may be determined by the speed control system 12 as the vehicle 1 approaches a detected speed bump 40. As shown, the vehicle 1 travels along the route path at a designated road speed limit 34. Once the speed bump 40 has been detected by the control system 12 of the vehicle 1, the proximity 44 of the vehicle 1, along the route path 200, to the speed bump 40 is determined using the current vehicle position 38 and the speed bump position 40. The speed control system 12 may then determine a threshold distance 42 from the speed bump position 40 to start decelerating the vehicle 1. The threshold distance 42 may be determined based on a reference declaration parameter 36, such as a deceleration limit, and a difference between the current vehicle speed and the speed limit for the speed bump 40. As noted previously, the speed limit associated with the speed bump 40 may be determined based on the speed bump information received from the geographic information system 6. When the vehicle 1 reaches the threshold distance 42, the speed control system 12 may output a control signal to the drive system 4 for controlling the vehicle 1 according to the reference deceleration parameter 36. In this example, the vehicle 1 will therefore decelerate, reducing speed at a constant rate, to the speed limit associated with the speed bump 40. The vehicle 1 comfortably traverses the speed bump 40 at the speed limit associated with that speed bump and the speed of the vehicle 1 subsequently increases to return to the road speed limit 34. Although not described in detail here, it shall be appreciated that the vehicle 1 may include one or more other control systems (not shown) for controlling the vehicle speed during ordinary driving between speed bumps and the speed control system 12 may be configured to take over vehicle speed control, in the manner described above, as the vehicle 1 approaches the detected speed bump 40, for example upon reaching the threshold proximity to the detected speed bump. In other examples, the speed control system 12 may control the vehicle speed along the entire path towards the target destination. A method of controlling the vehicle speed whilst driving towards a target destination, shall now be discussed with additional reference to Figures 6 and 7. Figure 6 shows an exemplary method 400 of controlling the speed of the vehicle 1 as it travels along a route path to a target destination, navigating speed bumps along the way. As previously described, the vehicle 1 may therefore be operating in an autonomous driving mode, during which the vehicle steering and speed control may be automatically controlled to drive the vehicle 1 towards a target destination. The target destination may have been provided by a user, for example by way of interaction with a human-machine interface device of the vehicle 1. Initially, at step 46, the speed control system 12 receives, or otherwise determines, the speed bump information from the geographic information system 6. For example, the speed control system 12 may receive a HD map from the geographic information system 6, which maps an area encompassing the current vehicle position and the target destination. The HD map may include annotated speed bump information. In this example, the speed bump information may therefore be provided by way of the annotated features of the HD map, indicating the position of each speed bump in the mapped area. In other examples, it shall be appreciated that the speed control system 12 may receive the speed bump information in other forms instead, and may for example receive a database of speed bump information for a particular area. In step 48, the speed control system 12 further receives a route path leading to the target destination from the path planning system 8. The route path includes a series of path passing points defining the route of the vehicle 1 towards the target destination and may be defined in the co-ordinate system of the HD map, for example, co-locating such features. To continue the previous example, the speed control system 12 may therefore receive a route path 200, substantially as described in Figure 4, which guides the vehicle 1 towards the target destination and passes over one or more speed bumps 20. At step 50, the speed control system 12 inspects the route path 200 to detect the nearest speed bump. In particular, the speed control system 12 inspects successive intervals of the route path 200 to check for an intersection with the indicated position of one of the speed bumps. This may be performed iteratively, for example checking a set number of intervals for an intersection during each iteration. By way of example, Figure 7 shows exemplary sub-steps for inspecting the route path 200 for an intersection with one of the speed bumps 20. In sub-step 52, the speed control system 12 may inspect the nth interval of the route path for an intersection with a speed bump, where n = 1 to N and N is a set number of intervals for inspection. The speed control system 12 may therefore initially inspect the first interval of the route path 200, i.e. when n = 1. The first interval shown in Figure 5, extends from the current position of the vehicle 1 to a first path passing point 24a. As mentioned previously, it is not intended for the control system 12 to be particularly limited in the manner of inspecting successive intervals of the route path for an intersection with a speed bump. To give an example though, successive intervals of the route path may correspond to respective road segments of the HD map 22, and the speed control system 12 may therefore inspect the first interval of the route path by identifying a respective road segment 22 corresponding to the first interval of the route path and check whether the HD map includes an annotated speed bump in the identified road segment. In another example, the speed control system 12 may inspect the first interval by determining the trajectory of the vehicle 1, e.g. as a vector, function, or equation, describing the movement from its current position to the first path passing point 24a based on the route path 200. The speed control system 12 may then compare the determined trajectory to the indicated positions of the speed bumps in the mapped area. For example, the speed control system 12 may iterate through the received speed bump positions, comparing the indicated position to the determined trajectory and checking for an intersection. In sub-step 54, the speed control system 12 checks whether the nth interval intersects any of the indicated speed bump positions. If no intersection is determined, the speed control system 12 proceeds to the next interval (i.e. n = n+1), in sub-step 56. The speed control system 12 may therefore proceed to inspect the second interval, extending between the first path passing point 24a and a second path passing point 24b, and repeat sub-steps 52 and 54. The speed control system 12 will continue to inspect successive intervals for an intersection as long as ‘n’ is less than the set number of inspected intervals, N. If an intersection is detected in one of the inspected intervals, in sub-step 54, the speed control system 12 identifies that speed bump as the first or nearest speed bump in the route path 200, in sub-step 58, and proceeds to determine the proximity thereto. For example, a speed bump 20a is shown to be intersected by the third interval of the route path 200 in Figure 4, between the second path passing point 24b and a third path passing point 24c. Accordingly, upon inspecting the third interval, the speed control system 12 shall detect the first speed bump 20a in the route path 200 and proceed to determine the proximity of the vehicle 1 thereto. Returning to Figure 6, the speed control system 12 therefore checks whether a first speed bump has been detected during the current iteration of the method 400, in step 60. If no speed bump has been detected after inspecting the Nth interval (i.e. n = N, where N is the set number of intervals to inspect), the speed control system 12 may conclude that the vehicle 1 is not currently approaching a speed bump 20 and the current iteration may be terminated. The drive system 4 may therefore be controlled according to the road speed limit, for example. As shown in Figure 6, the route path inspection will then be repeated, in step 52, during a subsequent iteration, where the speed control system 2 may configured to perform the inspection iteratively, for example at a prescribed frequency or whenever the vehicle 1 reaches the next path passing point. However, when a speed bump is detected in one of the inspected intervals, the speed control system 12 proceeds to determine the proximity of the vehicle 1, along the route path, to the first speed bump 20a, in step 62. It shall be appreciated that the speed control system 12 may determine the proximity according to various methods using the route path 200 and the position of the detected speed bump 20a. For example, the speed control system 12 may sum the interval distances together (adding the first and second interval distances together) before adding the remaining distance to the intersection, i.e. the remaining distance from the second path passing point 24b to the indicated position of the first speed bump 20a. Once the proximity to the speed bump has been determined, the speed control system 12 is configured to generate and output one or more control signals, in step 64, for controlling the vehicle speed to navigate the first speed bump 20a. The control signals are determined based on the determined proximity, the current vehicle speed, and the speed limit associated with the first speed bump 20a. However, various methods known in the art may be used for controlling the vehicle speed based on such parameters. To continue the earlier example, the speed control system 12 may use the vehicle speed control profile 300, shown in Figure 5, and output control signals when the vehicle 1 reaches the threshold distance 42 from the detected speed bump 20a. In this manner, the output control signals control the drive system 4 to decelerate the vehicle 1 at a constant rate (corresponding to the reference deceleration parameter 36), thereby reducing the vehicle speed to the associated speed limit associated by the point that the vehicle 1 reaches the first speed bump 20a. The vehicle 1 therefore comfortably traverses the speed bump 20a at the speed limit. Thereafter, the speed of the vehicle 1 may subsequently increase to return to the road speed limit 34, as steps 50 to 60 are repeated to determine the next speed bump in the route path 200. In this way, the vehicle 1 proceeds to drive autonomously towards the target destination and the vehicle speed is suitably controlled to response to, and comfortably navigate, speed bumps lying in the path of the vehicle 1. It is noted that the steps of the method 400 are merely exemplary in nature and are not intended to limit the control system. As such, it is understood that the steps involved may be altered, reordered, added and removed as will be appreciated by the person skilled in the art. It will also be appreciated that various changes and modifications can be made to the examples described above without departing from the scope of the present invention. In an example, when inspecting the route path, the speed control system 12 may be further configured to determine the second nearest speed bump and to adjust the speed control in dependence on the proximity of the first and second nearest speed bumps to avoid sudden changes in vehicle speed between the speed bumps. For example, depending on the proximity, the control signal(s) output to the drive system 4 may be configured to maintain the vehicle speed at the speed limit associated with the first speed bump, while travelling between the first and second speed bumps, and / or further reduce the vehicle speed to the speed limit associated with the second speed bump. In contrast to the previous examples, the speed control system 12 may therefore continue to inspect one or more further intervals of the route path, after detecting the first speed bump. For example, the speed control system 12 may proceed to inspect the set number of intervals and determine whether the route path intersects first and second speed bumps. Upon detecting a second speed bump in the route path, the speed control system 12 may be configured to determine the proximity to the second speed bump in substantially the same manner as the first speed bump, and / or determine the proximity between the first and second speed bumps in such a manner. Figure 8 shows another exemplary method 500 of controlling the speed of the vehicle 1 as it travels along a route path to a target destination, navigating speed bumps along the way. In this example, the speed control system 12 is further configured to determine the second nearest speed bump and to adjust the speed control in dependence on the proximity of the first and second nearest speed bumps. The method 500 may therefore proceed according to steps 46 and 48 substantially as described previously. However, in this example, the speed control system 12 proceeds to detect the nearest two speed bumps during the route path inspection, in step 50. For example, the speed control system 12 may inspect a set number of successive intervals of the route path 200 for an intersection with a first speed bump and, upon detecting the first speed bump, the speed control system 12 will continue to inspect any remaining intervals (up to the set number) for a further intersection. As described previously, this inspection may be performed iteratively, for example checking a set number of intervals during each iteration. Thereafter, the speed control system 12 may proceed to check, in step 52, whether a first speed bump is detected, and determine the proximity, along the route path, to that speed bump, in step 62, substantially as described previously. Thereafter, the speed control system 12 is further configured to check, in step 66, whether a second speed bump was detected in the route path 200. In the absence of a second speed bump detection, the speed control system 12 is configured to generate and output one or more control signals, in step 64, for controlling the vehicle speed to navigate the first speed bump 20a, substantially as described previously. However, if a second speed bump is detected, in step 66, the speed control system 12 proceeds to determine the proximity of the first speed bump to the second speed bump, in step 68. Again, it shall be appreciated that the speed control system 12 may determine the proximity of the first and second identified speed bumps according to various methods 5 known in the art, and the invention is not particularly limited in this respect. Thereafter, the speed control system 12 proceeds to generate and output one or more control signals for controlling the vehicle speed, in step 70, based on the proximity of the vehicle to the first speed bump and the proximity of the first and second speed bumps. 10 Such control signals may be output to the drive system 4 to control the vehicle speed substantially as described in step 64, further adjusting the speed control to avoid sudden changes in speed between the speed bumps, depending on their proximity. For example, if the first and second speed bumps are within the threshold proximity of one another, the speed control system 12 may output control signals to maintain the speed limit associated 15 with the first speed bump between the first and second speed bumps and / or further reduce the vehicle speed to the speed limit associated with the second speed bump.

Claims

1. A control system for controlling vehicle speed to navigate a speed bump, the control system comprising one or more controllers configured to execute machine-readable instructions to:receive speed bump information for one or more speed bumps from a geographic information system, the speed bump information being indicative of a respective position in a co-ordinate system of each speed bump;receive a route path from a path planning system of the vehicle, the route path comprising a series of path passing points defining a route of the vehicle, in the coordinate system, towards a target destination;inspect successive intervals of the route path, defined between respective pairs of the path passing points, for an intersection with the indicated position of at least one of the one or more speed bumps; andwhen a first speed bump in the route path is detected by the inspection:determine the proximity of the vehicle, along the route path, to the first speed bump; andoutput a control signal for controlling the vehicle speed whilst approaching the first speed bump based on:(i) the determined proximity;(ii) a current vehicle speed; and(iii) a speed limit associated with the first speed bump.

2. The control system of claim 1, wherein the speed bump information further comprises information indicative of a speed limit associated with each speed bump.

3. The control system of claim 2, wherein the speed bump information further comprises information indicative of a classification of each speed bump as one of a plurality of speed bump classifications, each speed bump classification being associated with a respective speed limit.

4. The control system of claim 3, wherein the plurality of speed bump classifications comprise:a speed bump,a speed hump, anda speed table.5 The control system of any one of claims 2 to 4, wherein the control system is configured to determine the speed limit associated with the first speed bump based on the speed bump information received for that speed bump.

6. The control system of any preceding claim, wherein outputting the control signal for controlling the vehicle speed further comprises:determining a threshold distance from the first speed bump based on a reference deceleration parameter and a difference between the current vehicle speed and the speed limit for the first speed bump; andoutputting the control signal for controlling the vehicle speed according to the reference deceleration parameter when the determined proximity reaches the threshold distance.

7. The control system of claim 6, wherein the reference deceleration parameter is a deceleration limit for the vehicle.

8. The control system of any preceding claim, wherein the control system is configured to receive a high-definition map from the geographic information system, and wherein the control system is configured to determine the speed bump information from the high-definition map.

9. The control system of claim 8, wherein the high-definition map comprises one or more annotated speed bumps.

10. The control system of claim 9, wherein the high-definition map further comprises one or more roads divided into a plurality of road segments, and wherein the series of path passing points correspond to successive endpoints of the plurality of road segments arranged along the route path.

11. The control system of claim 10, wherein the control system further comprises the path planning system, and wherein the path planning system is configured to determine the route path based on the received high-definition map.

12. The control system of any preceding claim, wherein the one or more controllers are configured to receive a current vehicle position from a navigation system of the vehicle.

13. The control system of claim 12, when dependent on claim 11, wherein the path planning system is configured to determine the route path based on the high-definition map and the current vehicle position.

14. The control system of any preceding claim, wherein the control system is configured to iteratively inspect a set number of successive intervals of the route path for the speed bump intersection.

15. The control system of any preceding claim, wherein the control system is configured to inspect one or more successive intervals of the route path for a second speed bump in the route path, more distal than the first speed bump, the second speed bump being detected where the indicated position of another one of the one or more speed bumps is intersected by a respective one of the inspected one or more intervals; andwhen a second speed bump is detected in the route path, the one or more controllers are configured to output the control signal for controlling the vehicle speed based on a proximity of the first speed bump to the second speed bump.

16. A vehicle comprising the control system of any one of the claims 1 to 15.

17. A method for controlling a vehicle to navigate a speed bump, the method comprising:receiving speed bump information for one or more speed bumps from a geographic information system, the speed bump information being indicative of a respective position in a co-ordinate system of each speed bump;receiving a route path from a path planning system of the vehicle, the route path comprising a series of path passing points defining a route of the vehicle, in the coordinate system, towards a target destination;inspecting successive intervals of the route path, defined between respective pairs of the path passing points, for an intersection with the indicated position of at least one of the one or more speed bumps; andwhen a first speed bump in the route path is detected by the inspection: determining the proximity of the vehicle, along the route path, to the first speed bump; andoutputting a control signal for controlling the vehicle speed whilst approaching the first speed bump based on:(i) the determined proximity;(ii) a current vehicle speed; and(iii) a speed limit for the first speed bump.5 18. A computer program product, comprising computer readable instructions which,when the program is executed by one or more processors cause the one or more processors to perform the method of claim 17.

19. A computer readable medium comprising instructions which, when executed by a 10 computer, cause the computer to perform the steps of the method of claim 17.27

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