GB2584398A

GB2584398A - Controller for active vanes of a vehicle

Info

Publication number: GB2584398A
Application number: GB1906405.4A
Authority: GB
Inventors: Ersanilli Vincent; Dutta Nilabza; Bradshaw-Martin Heather; Granger Rob; Walters Jason
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2019-05-07
Filing date: 2019-05-07
Publication date: 2020-12-09
Anticipated expiration: 2039-05-07
Also published as: GB201906405D0; DE102020112291A1; GB2584398B

Abstract

A controller and method for controlling an active brake system of a vehicle 100 including a brake and one or more movable vanes 108 (e.g. to open or close the front grille 470 to vary the air flow to the brakes for cooling, see figs. 2A, 2B). The controller receives an air vane status input (e.g. current angular vane position, error or fault state, power supply to actuator), selects a thermal brake model based on this, uses the model to estimate brake temperature and outputs control signals for the active brake system based on the brake temperature. A first thermal model may correspond to the vanes being open and a second thermal model to the vanes being closed. The output may control the vane position and/or a brake fade warning providing pedal feedback. Also claimed is a controller which receives an input indicative of a wading mode of the vehicle (i.e. re travelling through water 460) from a wading sensor 440 and outputs a signal to control the vanes to be open when the vanes are not at least partially submerged and optionally to remain in their current position when the vanes are submerged.

Description

Controller for active vanes of a vehicle

TECHNICAL FIELD

The present disclosure relates to a controller for active vanes of a vehicle and particularly, but not exclusively, to a controller for an active brake system of a vehicle, the active brake system comprising one or more moveable vanes and a vehicle brake system. Aspects of the invention relate to a controller, a system, and to a vehicle. Aspects of the invention also relate to a method of controlling an active brake system of a vehicle.

BACKGROUND

Brake systems can make use of by the flow of air which is displaced by the motion of a vehicle to provide one or more additional cooling mechanisms for a vehicle brake system. One or more ducts or underbody ramps can be located at the front of vehicle (for example, behind a front grille of the vehicle or under the vehicle); when the vehicle is moving, the air in front of the vehicle is forced either under the vehicle or through the opening in the grille and along these ducts or ramps. The ducts/ramps can then direct the air flow onto the vehicle brake to provide a stream of cooling air to the vehicle brake.

Whilst this additional cooling typically comprises less than half of the cooling applied to a vehicle brake (the remaining cooling can be provided by the fan moment of the wheels, for example), and is only really effective at relatively high vehicle speeds, the additional cooling is very important is during periods of high brake use, for example during rapid deceleration of the vehicle. However, the openings of the ducts/ramps, although needed to direct the air flow to provide this additional cooling, can contribute to aerodynamic drag. Fuel efficiency of the vehicle may therefore be affected.

It can therefore be desirable to provide such additional cooling to a vehicle brake when required, whilst minimising increases in aerodynamic drag during normal operation of a vehicle.

SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide a controller for an active brake system 35 of a vehicle, the active brake system comprising one or more moveable vanes and a vehicle brake system, a system comprising the controller and the active brake system, a vehicle comprising the system, a method of controlling the active brake system of the vehicle, and a computer program comprising instructions that when executed by hardware processor(s) cause the method to be performed, as claimed in the appended claims.

According to an aspect of the present invention, there is provided a controller for an active brake system of a vehicle, the active brake system comprising one or more moveable vanes and a vehicle brake system. The controller is configured to: receive one or more input signals, the one or more input signals comprising at least one signal associated with a status of the one or more moveable vanes; select a thermal brake model of the active brake system in dependence on the received one or more input signals; determine an estimated temperature of the vehicle brake system in dependence on the selected thermal brake model; and output, in dependence on the estimated temperature, one or more signals to control the active brake system. Improved control of the active brake system may therefore be provided, and fuel efficiency may be improved during normal operation of the vehicle.

As used herein, a feature being "associated with" the one or more moveable vanes comprises any feature, information, status, signal or error state, for example, which is dependent on, or provided from, or comprises information about any part of the subsystem of the movable vanes. For example, information associated with the one or more moveable vanes can comprise any information regarding one or more motors controlling movement of the movable vanes (for example as part of an actuating mechanism), one or more linkages of the actuating mechanism or any other part of the actuating mechanism, or one or more of the vanes themselves.

The controller can comprise one or more electronic processors having an electrical input for receiving the one or more input signals, an electrical output for outputting the one or more signals to control the active brake system, and an electronic memory device electrically coupled to the electronic processor and having instructions stored therein, wherein the processor being configured to select a thermal brake model and determine an estimated temperature of the vehicle brake system comprises the one or more electronic processors being configured to access the memory device and execute the instructions stored therein such that it is operable to perform the operations to select the thermal brake model and determine the estimated temperature of the vehicle brake system.

According to an aspect of the present invention, there is provided a controller for an active brake system of a vehicle, the active brake system comprising one or more moveable vanes and a vehicle brake system. The controller is configured to receive one or more input signals indicative of a wading mode of operation of the vehicle. The one or more input signals may be received from a wading sensor and/or the one or more signals may be received in dependence on direct user input. The controller is configured to output, in dependence on the one or more input signals, one or more signals configured to control a position of the one or more moveable vanes. When the one or more input signals are received from the wading sensor, they may indicate a depth of wading.

When the depth of wading is such that the one or more moveable vanes are not at least /5 partially submerged, the output signals are configured to control the one or more movable vanes to be in an open position. Optionally, when the depth of wading is such that the one or more moveable vanes are at least partially submerged, the output signals are configured to control the one or more moveable vanes to remain in their current position. By only actuating the vanes when they are not in contact the water, extraneous stress or force on the actuating mechanism can be reduced because actuating mechanisms of the vane do not have to act against hydrodynamic forces from the water. Lifetime of the active brake system may therefore be improved.

The controller can comprise one or more electronic processors having an electrical input for receiving the one or more input signals indicative of a wading mode, an electrical output for outputting one or more signals to control the position of the one or more movable vanes, and an electronic memory device electrically coupled to the electronic processor and having instructions stored therein, wherein the processor being configured to output one or more signals comprises the one or more electronic processors being configured to access the memory device and execute the instructions stored therein such that it is operable to perform the operations necessary to output the one or more signals in dependence on one or more input signals to control the position of the one or more movable vanes.

According to an aspect of the present invention there is provided a system comprising any aspect or embodiment of the controller and an active brake system, the active brake system comprising one or more moveable vanes and a vehicle brake system. According to an aspect of the present invention, there is provided a vehicle. The vehicle comprises any aspect or embodiment of said system. Optionally, the vehicle brake system is a brake by wire vehicle brake system, i.e. comprises a vehicle brake which operates using brake by wire technology.

According to an aspect of the present invention, there is provided a method of controlling an active brake system of a vehicle, the active brake system comprising one or more moveable vanes and a vehicle brake system. The method comprises: receiving one or more input signals, the one or more input signals comprising at least one signal associated with a status of the one or more moveable vanes; selecting a thermal brake model of the active brake system in dependence on the received one or more input signals; determining an estimated temperature of the vehicle brake system in dependence on the selected thermal brake model; and outputting, in dependence on the estimated temperature of the vehicle brake system, one or more signals to control the active brake system.

According to an aspect of the present invention, there is provided a computer program comprising instructions that when executed by one or more hardware processors cause it or them to perform the method of any aspect or embodiment.

The vehicle brake system can comprise a vehicle brake which has brake discs and pads for friction braking, as well as one or more hydraulic elements and associated electronics for controlling the movement of the pads onto and off the brake discs. Optionally, the vehicle brake system can comprise any associated electronics for implementation of a brake by wire system. The cooling arrangement described herein may provide cooling airflow to the brake disc(s), as well as to the brake pads and/or to the brake fluid so associated with the hydraulics to provide additional cooling of the brake fluid, as appropriate.

The method may comprise, or the controller may be configured to, control, in dependence on the one or more output signals, a fade warning assist system of the active brake system, optionally to provide feedback to a user of the vehicle. The method may comprise, or the controller may be configured to, control a pedal of the vehicle brake to provide this feedback to a user. By providing feedback to the user, for example physical feedback via the brake pedal, or other visual or auditory signals or warnings, the user may be made aware of a potentially reduced condition state of the vehicle brakes (i.e. that the vehicle brakes are overheating); this can be particularly advantageous in a brake by wire vehicle system, since the physical decoupling of the brake pedal from the traditional hydraulics/pneumatics in normal use of the vehicle will remove the physical feedback which is typically experienced by a user.

Optionally, the active brake system comprises one or more actuating mechanisms configured to adjust a position of the one or more moveable vanes. In other words, the moveable vanes are actuated by one or more actuating mechanisms.

The method may comprise, or the controller may be configured to, control, in dependence on the one or more input signals (for example, to control the vanes via one or more additional output signals generated in dependence on the received input signals), the one or more actuating mechanisms to adjust a position of the one or more moveable vanes. By controlling movement or position of the movable vanes in dependence on the input signal(s), pre-emptive movement of the movable vanes can be facilitated, which can reduce the risk that the movable vanes necessarily remain in the closed position when it is desirable for the vanes to be open. For example, if the actuating mechanisms are unable to move the vanes, for any reason, but cooling of the vehicle brake is required, it is desirable that the vane(s) are already positioned in an open position, rather than a closed position, when the actuating mechanism(s) become unable to move them. More efficient cooling of the vehicle brake can therefore be provided.

Optionally, the received one or more input signals comprise a signal indicative of a wading mode of operation of the vehicle. The method may comprise, or the controller may be configured to, control, in dependence on the signal indicative of a wading mode, the one or more actuating mechanisms to adjust a position of the one or more moveable vanes from a closed position to an open position. By pre-emptively opening the movable vanes before the vehicle enters the water, stress and other wear and tear on the movable vanes and their associated mechanisms can be reduced, since the actuating mechanisms need not operate against hydrodynamic forces from the water by opening the vanes whilst the vehicle is in the water.

The method may comprise, or the controller may be configured to, control, in dependence on the one or more output signals, the one or more actuating mechanisms to adjust a position of the one or more moveable vanes. By adjusting the position of the one or more vanes in response to the output signals, more efficient cooling of the vehicle brake can be provided. For example, when the temperature estimate indicates that the vehicle brake is hot, the movable vanes may be controlled to move to an open position, allowing an additional cooling stream of air to be directed onto the vehicle brake when the vehicle is in motion. When the thermal brake model estimates the brake temperature is sufficiently cooled, the vanes may be closed again by the controller to reduce aerodynamic drag and the thermal model switched accordingly. This brake temperature feedback system can facilitate more efficient and effective brake cooling, and so can reduce any potential overheating of the vehicle brakes in a high brake use situation.

Optionally, the at least one signal associated with a status of the one or more moveable vanes is received from the one or more actuating mechanisms and indicates a current position of the one or more moveable vanes (i.e. whether the vane(s) are open or closed). By receiving the current position of the movable vanes in the input signal, the controller can be configured to only switch the thermal model once confirmation of the position of the movable vane(s) has been received. This can help to minimise or prevent overheating of the vehicle brake in a situation where the movable vanes are instructed to open by the controller (e.g. output signals are provided to control the vanes) but where they do not actually open, since the controller will then not switch the thermal brake model to an open model (because confirmation that the vanes are open has not been received). A more accurate estimation of the vehicle brake temperature can therefore be provided.

Optionally, the at least one signal associated with a status of the one or more moveable vanes comprises a status of the one or more actuating mechanisms. Optionally, the status of the one or more actuating mechanisms comprises a temperature of the one or more actuating mechanisms. The method may comprise, or the controller may be configured to, select the thermal brake model in dependence on the status of the one or more actuating mechanisms. The method may comprise, or the controller may be configured to, select the thermal brake model in dependence on the temperature of the one or more actuating mechanisms satisfying a predetermined criterion, optionally in dependence on the temperature of the one or more actuating mechanisms exceeding a first, predetermined, temperature threshold.

Such an approach can be advantageous because some actuating mechanisms cannot operate above a certain temperature threshold. For example, when there is an over-temperature condition associated with the actuating mechanism(s), the one or more moveable vanes can no longer be actuated. By monitoring the temperature of the actuating mechanism of the movable vanes, the vanes can be pre-emptively opened before this over-temperature condition of the actuating mechanism occurs. The thermal brake model can then be switched to the first model, corresponding to an open position of the one or more moveable vanes. By pre-emptively opening the vanes before an over-temperature condition of the actuating mechanism occurs (and switching the thermal model accordingly), additional cooling of the vehicle brake is available on the off-chance that the vehicle brake starts to overheat (even if an over-temperature condition of the actuating mechanisms would prevent the movable vanes being actuated at that time). It will be understood that the moveable vane(s) could also be pre-emptively closed, if this is indicated by the current mode of vehicle operation (e.g. wading mode).

Optionally, the thermal brake model is an empirical model. The method may comprise, or the controller may be configured to, select a thermal brake model by switching between (at least) a first thermal brake model and a second thermal brake model. In one example, the first model corresponds to a thermal model of the vehicle brake when the one or more moveable vanes are in an open position, and the second model corresponds to a thermal model of the vehicle brake when the one or more moveable vanes are in a closed position. In other words, there may be two models or there may be three or more thermal brake models to select or switch between. For example, one or more additional thermal brake models may be provided which correspond to respective intermediate position(s) of the one or more moveable vanes. Optionally, the thermal brake model comprises a cooling model; optionally, a convective cooling contribution of the cooling model is reduced in the second model as compared to the first model. In other words, the second model considers there to be little or no cooling contribution from the ducts, whereas the first model accounts for a contribution from a flow of cooling air which is dependent on the vehicle speed.

Optionally, the status of the one or more moveable vanes may indicate that the one or more moveable vanes are in a closed position or that a position of the one or more moveable vanes is unknown. The method may comprise, or the controller may be configured to, select the thermal brake model to be the second model in dependence on this status. By switching to a closed thermal brake model when a position of the movable vane(s) is unknown, the temperature of the vehicle brake will not be underestimated. In particular, by assuming that the vanes are closed, the vane closed scenario of the vehicle brake temperature is estimated, i.e. the temperature when there is no additional cooling being provided; if the vanes are actually open, and thus additional cooling is being provided to the vehicle brake system but is not being taken into account by the thermal brake model, then features associated with overheating of the vehicle brakes may be implemented unnecessarily. However, the vehicle will not be in a situation where the vehicle brake is overheating because the model is underestimating the temperature by assuming that the vanes are open, and therefore cooling the brake, when they are in fact closed.

Optionally, the status of the one or more moveable vanes indicates an error state of the one or more moveable vanes. The method may comprise, or the controller may be configured to, calibrate the one or more moveable vanes in dependence on the error state. The method may comprise, or the controller may be configured to, switch from the first model to the second model in dependence on the indicated error state. Optionally, the error state indicates at least one of: a supply voltage fault; a maximum age of the received one or more input signals; a blockage of the one or more moveable vanes; an over-temperature condition associated with the one or more moveable vanes; an electrical fault associated with the one or more moveable vanes; or a mechanical fault associated with the one or more moveable vanes.

By switching to a closed thermal brake model when an error state occurs, the temperature of the vehicle brake will not be underestimated. As described above, if the vanes are actually open, and thus additional cooling is being provided to the vehicle brake system but has not been taken into account by the thermal brake model in the brake temperature estimation, it is understood that vehicle features may be implemented unnecessarily in response to a perceived overheating brake. However, by assuming that the vanes are closed, it is the vane closed scenario of the vehicle brake temperature which is estimated.

The positions of one or more movable vanes located within a vehicle, for example within a front grill of the vehicle, are controlled to adjust the level of cooling air directed onto a brake system of the vehicle. A thermal model of the brake system is selected to correspond to the position of the movable vanes, facilitating more accurate estimation of the temperature of the vehicle brake system. A temperature based feedback system may control the position of the movable vanes to further adjust the level of cooling air.

Within the scope of this application it is expressly intended that the various aspects, ll,) 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 /5 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 1A shows a block diagram of a system of a vehicle in accordance with an embodiment of the invention; Figure 1B shows a perspective view of a moveable vane arrangement of the system of Figure 1A; Figures 2A and 2B provide a schematic illustration of the effect of the position of the vane of Figure 1B on the air flow onto a vehicle brake (Figure 2A corresponds to a fully open vane and Figure 2B corresponds to a fully closed vane); Figure 3 shows a block diagram of a thermal brake model in accordance with an embodiment of the invention; and Figure 4 provides a schematic illustration of vehicle wading in accordance with an embodiment of the invention; Figure 5 shows a block diagram of a controller in accordance with an embodiment of the invention; I0 Figure 6 shows a flow diagram of a method of controlling an active brake system in accordance with an embodiment of the invention; and Figure 7 shows a vehicle in accordance with an embodiment of the invention.

DETAILED DESCRIPTION

A controller 102 for an active brake system 104 of a vehicle 100 is described herein with reference to accompanying Figures 1A and 1B and Figures 2A and 2B. It will be understood that controller 102 can be incorporated within the active brake system 104, or can be implemented as a separate controller, which may optionally also control one or more other vehicle systems of vehicle 100.

To reduce aerodynamic drag on vehicle 100 while still providing an additional cooling stream of air to a brake disc (and optionally brake fluid) of a vehicle brake system, active brake system 104 comprises both a vehicle brake (or vehicle brake system) 106 and one or more movable vanes 108, which are typically located near or at the front of vehicle 100. For example the vanes 108 can be located behind, or comprising, a front grille 470 of vehicle 100 (see Figure 4), which grille 470 opens onto a duct 122, as illustrated in Figure 1 B. The vanes may additionally or alternatively be located below the grille 470 under the body of the vehicle (see Figure 4) and open onto a duct 122. For example, as shown in the Figures there may be only one vane, but there may also be two vanes, three vanes, or more than three vanes as appropriate, depending on the configuration of the vehicle. The angle, or angular orientation/position of the movable vane(s), 108 can be adjusted by one or more actuating mechanisms 110 in order to adjustably control when, and how much, additional cooling air is applied to the vehicle brake 106 via the duct 122.

The angular orientation of the vanes 108 affects the amount of cooling air which reaches the vehicle brake 106. As can be seen from Figure 2A, when the movable vanes are fully open (the position of the vanes themselves is not shown in Figure 2A), the flow of cooling air 124 directed onto the vehicle brake 106 is at a maximum. In contrast, as shown in Figure 2B, when the moveable vanes are fully closed (the position of the vanes themselves is not shown in Figure 2B), no cooling air reaches the vehicle brake 106 from the front of the vehicle via the ducts (although cooling from the fan moment of the wheels is provided). By providing such movable vanes 108, cooling air can be provided to the vehicle brake 106 only when required (i.e. during periods of rapid deceleration of the vehicle 100), whilst reducing aerodynamic drag during other periods of vehicle operation.

However, since the position (used herein to refer to angle or angular orientation) of the movable vanes 108 influences the amount of cooling air which flows through duct 122, and thus the degree of cooling experienced by the vehicle brake 106, it is important to know the position of the movable vanes 108. For example, the position of the movable vanes 108 can be against one or more end stops in a fully open or fully closed position, or in an intermediate position between these two end points (for example during transit or movement of the vanes, or at an intermediate vane position, depending on the vehicle configuration).

Knowing the position of the vanes can facilitate improved estimation of the temperature of the vehicle brake 106, as will be described herein. This can be of particular importance in brake by wire vehicle braking systems (in which brakes are controlled through electrical means, replacing many of the traditional hydraulic or pneumatic pump systems with electronic sensors and actuators). In normal use, a user of a brake by wire braking system does not have physical feedback from the vehicle brake 106 because there is no direct hydraulic connection between the driver's foot and the vehicle brake 106. For example, there is no sensation of brake pedal fade when braking (the sensation of pushing the pedal further to slow down the vehicle same amount, usually an indication of hot brakes), and thus no physical indication is provided to a driver that vehicle brake 106 is overheating. It can therefore be important to model or otherwise estimate the thermal condition (i.e. the temperature and other temperature related properties) of the vehicle brake 106 in order to provide appropriate feedback to the user (e.g. a driver of the vehicle) regarding the vehicle brake condition. In particular, the variable cooling effect on the vehicle brake 106 produced by the position of the movable vanes 108 needs to be correctly taken into account, in order that appropriate feedback is given to the user by one or more vehicle systems.

To take this variable cooling effect into account, controller 102 is configured to receive one or more input signals (either from the active brake system 104, as illustrated in Figure 1A, or from another suitable vehicle system, as appropriate, for example from the vehicle system which controls the mode of operation of the vehicle). The one or more input signals 112 received by the controller 102 comprise at least one signal 112a which is associated with a status of the movable vanes 108, and may be received from from the one or more actuating mechanisms 110. For example, the at least one signal 112a received from the actuating mechanism(s) can contain information representative of a status of the movable vane(s) 108, such as the current (angular) position of the vane(s), or the current or voltage being supplied to the actuating means or mechanism 110 to actuate the vane(s) 108. The at least one signal 112a associated with a status of the movable vanes 108 can additionally or alternatively comprise one or more fault conditions associated with the vanes 108 (for example, an over voltage supply, an unknown position of the vanes, a mechanical fault of the vanes, a fault in the calibration process of the vanes, a blockage of the vanes, etc.).

Additionally or alternatively, the information representative of a status of the movable vane(s) 108 can comprise an indication of one or more fault conditions associated with the actuating mechanism(s) 110 which control the vanes 108, for example an over-temperature condition, a maximum age of a signal, or a loss of signal (as will be described below in more detail). In essence, the at least one signal acts as a feedback to the controller 102 on any aspect of the operation of the movable vanes 108 that can affect the cooling of the vehicle brake 106.

Controller 102 is configured to select a thermal brake model 114 in dependence on the one or more input signals 112 received. In particular, selecting a thermal brake model comprises the controller being configured to switch between at least a first thermal brake model and a second thermal brake model. The first (thermal brake) model 114a corresponds to a thermal model of the vehicle brake 106 when the one or more moveable vanes 108 are in an open position (as shown in Figure 2A). The second (thermal brake) model 114b corresponds to a thermal model of the vehicle brake 106 when the one or more moveable vanes 108 are in a closed position (as shown in Figure 2B). It will be understood that one or more additional thermal brake models 114 may be provided for selection by the controller, for example corresponding to one or more intermediate positions of the or more movable vanes 108, depending on the configuration of the vehicle. The controller 102 is configured to determine an estimated temperature 120 of the vehicle brake 106 in dependence on the selected thermal brake model (this process will be described below in more detail with reference to Figure 3) and to output, in dependence on the estimated temperature 120, one or more signals 116 to control the active brake system 104.

The one or more output signals 116 can be configured to control a fade warning assist system 118 of the active brake system 104. The fade warning assist system 118 can provide feedback to a user of the vehicle 100 that is indicative of an overheating vehicle brake 106 (i.e. to warn of the equivalent of brake pedal fade). For example, a pedal of the vehicle brake 106 can be controlled with the one or more output signals 116 from the controller 102 in order to provide a user with physical feedback indicative of brake fade. Additionally or alternatively, one or more warning systems can be controlled in response to the output signals 116 in order to provide a user with visual or auditory feedback -for example, a warning light may be displayed, or a warning sound may be played to a user to warn them that the vehicle brake 106 is hot.

The one or more output signals 116 may additionally or alternatively be configured to control the actuating mechanism(s) 110 in order to adjust a position of the one or more moveable vane(s) 108. For example, if the temperature estimate 120 of the vehicle brake 106 indicates that the vehicle brake 106 has a temperature above a predetermined temperature (which can be defined empirically or numerically, and is suitable for said vehicle configuration), the output signals 116 may cause the actuating mechanism 110 to open the movable vanes 108 in order to allow additional cooling air to be directed onto the vehicle brake 106. In this way, overheating in the vehicle brake 106 can be reduced by dynamically controlling cooling of the vehicle brake 106 with vanes 108. Once the brake 106 has cooled, other output signals 116 can be output by controller 102 to readjust the position of the vanes 108, whereupon the controller 102 can select a different thermal brake model 114, as appropriate (i.e. a thermal brake model corresponding to an intermediate vane position or a closed vane position, depending on the adjusted position of the vanes 108).

The controller 102 can comprise one or more electronic processors having an electrical input for receiving the one or more input signals described above, an electrical output for outputting one or more signals, and an electronic memory device electrically coupled to the electronic processor and having instructions stored therein. The controller being configured to output one or more signals comprises the one or more electronic processors being configured to access the memory device and execute the instructions stored therein such that the processor(s) are operable to perform the operations required to output the one or more signals, as described above.

The processor(s) of controller 102 can communicate with one or more other vehicle systems or devices via a bus subsystem. These other systems or devices may include a storage subsystem (e.g. the electronic memory device), including, for example, a memory subsystem and a file storage subsystem, and a network interface subsystem for example. Network interface subsystem can provide an interface to outside networks (for example, other vehicle networks to connect with one or more other vehicle systems). Memory used in the storage subsystem can include a number of electronic memory devices including a main random access memory (RAM) for storage of instructions and data during program execution and a read only memory (ROM) in which fixed instructions are stored. The file storage subsystem can provide persistent storage for program and data files. For example, a computer program can be stored in the file storage subsystem, the computer program comprising instructions that when executed by the one or more processors of the controller 102 cause the controller to perform the operations described herein.

The thermal brake models 114a, 114b to be selected between by the controller 102 can be stored in the electronic memory device of the controller 102 and accessed by the electronic processor(s) of controller 102. As described with reference to Figure 3, each thermal brake model 114 can take one or more inputs 340. These inputs can comprise one or more measured properties of the vehicle 100 in operation, or of the surrounding environment: for example, inputs 340 can comprise vehicle velocity, brake torque, the angular velocity the wheels of vehicle 100, and/or the ambient temperature and atmospheric pressure, among other input factors.

The cooling effect of the airflow from the movable vanes 108 is modelled within each thermal brake model as part of a convective cooling contribution 334 of a cooling sub-model 330 of thermal brake model 114. The cooling sub-model 330 can also comprise both radiative 332 and conductive 336 cooling contributions, which contributions be modelled numerically, parametrically, or based on empirical measurements, as appropriate. The cooling sub-model 330 is used in combination with one or more other sub-models (for example a model of the brake disc temperature 350 and a model of the brake fluid temperature 355) to form the overall thermal brake model 114.

The thermal brake model 114 may be parametric, numerical, or empirical. For example, the thermal brake model may be calibrated by measuring the temperature of brake discs and/or brake fluid of vehicle brake 106 whilst a vehicle is an operation, for different vane positions, and then determining an optimized set of calibration parameters to approximate each set of empirical data. It will be understood that changing the distribution of airflow onto the brake discs by adjusting the position of the movable vanes 108 requires a different set of calibration parameters to be used within the thermal brake model 114; in particular, a different set of calibration parameters is required for each of the different moveable vane positions and corresponding air flow states. This empirical approach can be computationally expensive (due to the need to determine calibration parameters for each vane position), and also expensive in terms of the time and equipment required to instrument a car in order gather suitable measurement data for determining said parameters. Such expense can be reduced by switching between only two different models representative of the extreme positions of the movable vanes 108 (open and closed), or by having only a few intermediate vane positions and corresponding thermal models 114.

The overall thermal brake model 114 can be used to estimate a temperature 120 of the vehicle brake 106, which temperature estimate 120 is then used by controller 102 to control active brake system 104 and one or more other vehicle systems, as is described above. For example, the controller 102 can output, in dependence on the estimated temperature 120, one or more signals 116 to control the fade warning assist, operation of a pedal of the vehicle brake (for example, by varying the resistance of the pedal), and/or the position of the movable vanes 108 themselves.

With reference to Figure 3, the temperature estimate 120 can comprise both a disc temperature estimate 126 and a fluid temperature estimate 128. The temperature estimate 126 may optionally be used within the calculation of the fluid temperature 128, depending on the particular configuration of the models, or vice versa. These disc fluid 128 and disc brake 126 temperature estimates allow for two different brake error conditions to be distinguished between; fluid leak (i.e. a loss of fluid from the brake) and brake fluid over-temperature. If the disc brake temperature 126 is estimated to be hot using model 350 and the cooling sub-model 330, and the disc fluid temperature 128 is estimated to be hot using model 355, then it can be determined that the vehicle brake 106 is hot; in this case, the movable vanes 108 can be opened to allow cooling the vehicle brake 106. This scenario is discussed above.

However, if the disc brake temperature 126 is estimated to be low using model 350 and cooling sub-model 330, but the brake fluid temperature 128 from model 355 is high, a /5 vehicle brake error state is detected which can be indicative of a fluid leak from the brake.

In the case of fluid leak, one or more brake circuits should be shut off. However, if the thermal brake model 114 underestimates the temperature 126 of the brake discs, leading to an erroneous determination of fluid leak, one or more brake circuits may be shut off incorrectly. This can cause the remaining fluid in the brake circuit to overheat quickly, reducing the effectiveness of the brakes. It can thus be important that the thermal brake model 114 correctly estimates the temperature of the brakes, in particular of the brake disc, and thus that the controller 102 correctly selects between the available thermal brake models 114 in dependence on a position of the one or more vanes 108.

As will be understood from the following description, in situations where the controller 102 has insufficient information regarding a status of the one or more movable vanes or the associated vane subsystem, a vane closed scenario of no additional cooling from movable vanes should be assumed, in order to prevent such an underestimation of the brake temperature.

Wading mode With reference to Figure 4, controller 102 is additionally or alternatively configured to control an active brake system 104 of vehicle 100 during a wading mode of operation, in which the vehicle 100 travels through water 460 instead of travelling on land 450. In particular, the controller is configured to receive one or more input signals indicative of a wading mode of operation of the vehicle, the one or more input signals being received from a wading sensor 440 of the vehicle 100.

The wading sensor may be a substantially downward facing ultrasonic transmitter and receiver. The wading sensor may be under the vehicle, on a door of the vehicle, or on an underside of a wing mirror of a vehicle, as appropriate. The wading sensor 440 is configured to detect a depth of wading of the vehicle 100 in water 460 and/or the presence of water itself (a depth of the water may be difficult to determine in certain deep water or snowy/icy environments). Additionally or alternatively, the input signal can be io received due to direct user input, for example, a driver of vehicle 100 may select a 'terrain mode' of vehicle operation while still on land 450, just before entering water 460 for example. 'Terrain mode' covers different types of driving terrains, including wade mode. The wading mode may be selected by the user (or automatically by the vehicle).

/5 In one example, if controller 102 determines from temperature estimate 120 that cooling of the vehicle brake 106 is required, output signals 116 can be configured to adjust a position of the movable vanes 108, as described above. However, during a wading mode (a terrain mode) of operation the vanes 108 can be partially or fully submerged under water. In this environment, it can be difficult to adjust the position of the one or more movable vanes 108 of the active brake system 104; in particular, movement of the vanes 108 can be hindered by the hydrodynamic forces of the surrounding water. Actuating mechanism 110 is typically not designed to undergo movement under the increased forces experienced during wading, and therefore damage to the actuating mechanism may occur.

Furthermore, during a wading mode of operation it is possible that debris and silt may be deposited on one side of the vanes 108, which could lead to one or more error states for the movable vanes (discussed below in more detail); such an error state can be caused by, for example, the debris or silt drying and sticking the vanes in a particular position.

Moreover, since aerodynamic drag on the vehicle 100 is not a consideration during a wading operation, there is no benefit in the movable vanes 108 remaining closed during wading.

It can therefore be desirable to pre-emptively open the vane(s) 108 before or during a 35 wading operation (i.e. when wading mode is activated by a user or in response to signals from the one or more wading sensors 440). This pre-emptive movement can be initiated based on the signals from the wading sensors, or based on the direct user input, with additional signals from the wading sensors 440 to provide details of the wading depth.

In particular, controller 102 is configured to output, in dependence on the one or more input signals indicative of a wading mode of operation, one or more signals configured to control a position of the one or more moveable vanes. When the received one or more input signals from the wading sensor 440 indicate a depth of wading is such that the one or more moveable vanes are not at least partially submerged (i.e. are still above the water), the output signals are configured to control the one or more movable vanes to be in an open position. Chances of the vanes 108 sticking in a closed position due to silt or debris accumulation is reduced, and the actuating mechanism 110 is not subject to increased forces since the vanes do not need to be moved during the wading operation.

Furthermore, when the received one or more input signals from the wading sensor indicate a depth of wading is such that the one or more moveable vanes are at least partially submerged, the output signals are configured to control the one or more moveable vanes to remain in their current position. In this way, controller 102 can help prevent the actuating mechanism from having to act against hydrodynamic forces of the water; extraneous stress or force on the actuating mechanism 110 can be reduced, since the position of the movable vanes 108 is not adjusted whilst the vanes 108 are in the water. Lifetime of the active brake system may therefore be improved.

The input signal(s) indicative of a wading mode of operation can be comprised within the one or more input signals 112 received by the controller 102 (as described with reference to Figure 1). Alternatively, the input signal indicative of a wading mode of operation can be received as a separate signal. Either way, controller 102 can be configured to select the appropriate thermal brake model 114 for the position of the movable vanes 108 during wading. For example, when, during the wading mode of operation, the movable vanes 108 are pre-emptively opened, the controller can select the appropriate thermal brake model 114 to be thermal brake model 114a, which corresponds to the movable vanes being in an open position (see Figure 2A). This can help facilitate more accurate monitoring of the temperature of the vehicle brake 106. Moreover, in the wading mode the movement of the vanes 108 can be controlled independently of the temperature estimate 120 which is determined by the controller 102; the cooling effect of the movable vanes 108 is not experienced at the low vehicle speeds such as those experienced during wading mode, nor is the cooling effect experienced when the vanes are fully submerged in the water, so there is no need to control the vanes 108 based on vehicle brake temperature. The positions of the vanes can be controlled based on information regarding wading depth or wading mode alone.

Error states With reference to Figure 5, examples of possible error states of the one or more movable vanes 108, and control of the movable vanes in the event of each such error, are described. Communication between the different control 'boxes' (i.e. control modules or elements, which may all be implemented within software) shown in Figure 5 is two-way, figuratively shown as two-way communication channel 590.

An indication of one or more error states can be received by the controller 102 in the one or more received input signals 112. For example, the at least one signal associated with the status of the one or more movable vanes can be a signal indicating one or more error states (or an error status) of the movable vanes 108. The controller 102 can be configured to select, or optionally switch between, different thermal brake models 114 in dependence on the error state(s) indicated by the received signals 112. For example, controller 102 can be configured to switch to the second thermal model 114b, which corresponds to the movable vanes being in an closed position (see Figure 2B), in dependence on the movable vanes 108 being in an error state. In this way, the temperature 120 of the vehicle brake 106 is estimated under a vane closed scenario (i.e. does not take into account any cooling effect from the air flow controlled by the movable vanes 108), and so is overestimated, rather than an underestimated. Brake lifetime may be improved by effective cooling of the brakes.

In normal operation of the active brake system 104, initialization of the movable vanes 108 occurs when the vehicle 100 is started, controlled by control box 500. When the power mode of vehicle 100 reaches a first power threshold (for example, a threshold indicative of the vehicle being turned on and/or driving having started), the position of the movable vanes 108 is calibrated by control box 500. During calibration, the movable vanes 108 are moved by the actuating mechanism 110 (controlled by the controller 102 with control box 500) from fully open to fully closed, and signals associated with the angular movement of the vanes 108 measured accordingly (e.g. current or voltage output of the actuating mechanism can indicate a position of the vanes).

Provided that no faults are detected during initialization, and the vanes are calibrated properly, position control box 510 of controller 102 controls the movable vanes to remain in a closed position and controller 102 selects the closed thermal brake model 114b accordingly. In normal vehicle operation, if a wading mode of operation is initiated, velocity of the vehicle 100 exceeds a threshold, or a temperature estimate 120 of a hot brake (either fluid or disc) is determined by the controller 102 (based on the thermal model 114), for example, position control box 510 controls the actuating mechanism 110 to open the movable vane(s) 108 to assist in cooling the vehicle brake 106. Once input signal(s) 112 indicating that the status of the one or more movable vanes 108 corresponds to the vanes being in an open position are received at controller 102, the controller 102 selects the thermal brake model 114a, which is indicative of an open /5 position of the movable vanes 108. The thermal brake model 114a is ideally not selected by the controller 102 until such confirmation of the status of the movable vanes is received via input signals 112, in order to reduce or minimize the risk that the thermal model is changed before the position of the movable vanes 108 is, since this could lead to an underestimation of the temperature 120 of the vehicle brake 106. Lifetime of the brakes may therefore be improved.

If the vehicle brake 106 subsequently cools down, the wading mode of operation is ended, or the vehicle velocity decreases, for example, the position control box 510 of controller 102 controls the actuating mechanism 110 to close the movable vanes 108, in order to end the additional cooling stream of air and so reduce aerodynamic drag of the vehicle (thereby increasing vehicle efficiency). Once input signal(s) 112 indicating that the status of the one or more movable vanes 108 corresponds to the vanes 108 being in a closed position are received at controller 102, the controller 102 selects thermal brake model 114b, which is indicative of a closed position of the movable vanes 108.

Alternatively, if the vehicle 100 is turned off and the power mode of the vehicle reduces, position control box 510 controls the movable vanes 108 to move to a resting position near the fully open position (although the vanes are not driven hard against the end stops of the open position in order to reduce stress on the actuating mechanism and wear of the movable vanes). This resting position also prevents the movable vanes 108 from freezing against the end stops (in the open position, but optionally in the closed position) whilst the vehicle is not in use. The controller then returns the control of the movable vanes 108 to the initialization control box 500 in anticipation of the vehicle next being turned on.

However, if during the initialisation phase control box 500 one or more error states are detected, the one or more movable vanes 108 may be controlled differently to the approach described above, and/or the controller 102 may execute different steps.

In one example, the at least one signal associated with a status of one or more moveable vanes comprised within received input signals 112 indicates an error state being a mechanical fault associated with the one or more moveable vanes 108. The 'associated' mechanical fault may be any mechanical fault internal to the subsystem of the movable vanes 108, including a fault with the actuating mechanisms 110. For example, one or more motors controlling movement of the movable vanes 108 may be broken or damaged or not responding, one or more linkages of the actuating mechanism 110 may be broken or damaged, or one or more of the vanes 108 themselves be broken. Such a mechanical fault can be generalised to include any mechanical fault which results in a reduction, or total loss, of the controller's ability to move one or more of the movable vanes 108.

If at any time the input signals 112 indicate there is such a mechanical fault, control box 520 controls the initialisation control box 500 to request that the movable vanes 108 are calibrated. If such a calibration is successful, this indicates the mechanical fault is spurious. Operation of the movable vanes then proceeds as described above with respect to position control box 510. However, if the calibration is not successful, the controller 102 either does not know, or cannot control, the position of the one or more movable vanes 108; the movable vanes are thus determined by controller 102 to be in a closed position. Upon receipt of the one or more input signals 112 confirming the mechanical fault error state, the controller 102 selects the appropriate thermal brake model for determining an estimated temperature 120 of the vehicle brake 106 to be thermal brake model 114b. This approach assumes a vane closed scenario in the event of a mechanical fault of the movable vane subsystem. In this way, the temperature of the vehicle brake 106 is not underestimated in the event of a mechanical fault.

In one example, the at least one signal associated with a status of one or more moveable vanes comprised within received input signals 112 indicates an error state being an electrical fault associated with the one or more moveable vanes. The 'associated' electrical fault may be any electrical fault internal to the subsystem of the movable vanes 108, including a fault with the actuating mechanisms 110. For example, one or more motors controlling movement of the movable vanes 108 may be exhibiting an electrical fault, or one or more other components of the actuating mechanism 110 may be exhibiting an electrical fault. Such an electrical fault can be generalised to include any electrical fault which results in a loss of ability to move one or more of the movable vanes 108, or which results in erroneous electrical signals being received by controller 102 such that the controller 102 is unable to determine a position of the movable vanes 108.

If at any time the input signals 112 indicate there is such an electrical fault, control box 530 controls the initialisation control box 500 to request that the movable vanes 108 are /5 calibrated. If such a calibration is successful, this indicates the electrical fault is spurious.

Operation of the movable vanes then proceeds as described above with respect to position control box 510. However, if the calibration is not successful, the effect of the electrical fault can be that the controller 102 does not know the position of the one or more movable vanes 108. The controller 102 thus determines that the movable vanes are in a closed position. Upon receipt of the one or more input signals 112 confirming the electrical fault error state, the controller 102 selects the appropriate thermal brake model for determining an estimated temperature 120 of the vehicle brake 106 to be thermal brake model 114b. This approach assumes a vane closed scenario in the event of an electrical fault of the electrical components of the movable vane subsystem. In this way, the temperature of the vehicle brake 106 is not underestimated in the event of an electrical fault.

In one example, the at least one signal associated with a status of one or more moveable vanes comprised within received input signals 112 indicates an error state being a supply voltage fault. The supply voltage fault may be any internal to the subsystem of the movable vanes 108, including a fault with the actuating mechanisms 110. For example, one or more motors controlling movement of the movable vanes 108 may be experiencing a supply voltage fault, or one or more components of the actuating mechanism 110 may be experiencing a supply voltage fault. Alternatively, such a supply voltage fault can be caused by a low battery or a degraded electrical system of the vehicle, for example.

If at any time there is such a supply voltage fault (except where an engine management system of vehicle 100 ascertains that the supply voltage fault is due to cranking of the engine, in which case the fault is disregarded), control box 540 controls the initialisation control box 500 to request that the movable vanes 108 are periodically calibrated. At the same time, supply voltage fault control box 540 logs a fault and controller 102 determines that the movable vanes are in a closed position. Upon receipt of the one or more input signals 112 confirming the supply voltage fault error fault, the controller 102 selects the appropriate thermal brake model for determining an estimated temperature 120 of the vehicle brake 106 to be thermal brake model 114b. This approach assumes a vane closed scenario in the event of a supply voltage fault of one or more electrical components of the movable vane subsystem, or any other supply voltage fault. In this way, the temperature of the vehicle brake 106 is not underestimated in the event of an electrical fault.

If at any time during the periodic calibration of the movable vanes 108 the supply voltage fault is rectified and the movable vanes are successfully calibrated, operation of the movable vanes then proceeds as described above with respect to position control box 510. For example, position control box 510 of controller 102 controls the movable vanes to move between an open and a closed position depending on a condition of the vehicle 100 (a brake temperature, a wading mode, etc.), and selects the thermal brake model 114, as appropriate, in dependence on received input signals 112. In this example, the at least one signal associated with a status of the one or more moveable vanes can comprise the position of the moveable vanes, as discussed above.

In one example, the at least one signal associated with a status of one or more moveable vanes comprised within received input signals 112 indicates an error state associated with a maximum age of the received one or more input signals 112. As discussed above, when controller 102 outputs one or more signals 116 to control the active brake system by moving one or more movable vanes 108, a different thermal model 114 may not be selected by the controller 102 until confirmation of the change of position of the movable vanes is received by the controller 102 in input signals 112. This approach can provide with more effective cooling by improving the accuracy of the brake temperature estimate 120, and thereby improve lifetime of the vehicle brakes. However, in order to maintain a correct selection of a thermal model 114 by the controller, it can be important to correlate the received input signals 112 with those output signals 116 which are configured to control the position of the movable vanes 108.

Control box 550 is activated when the output signals 116 are output by the controller 102. Control box 550 may comprise a counter or other mechanism configured to monitor a period of time between the outputting of output signals 116 and the subsequent receipt of input signals 112. If the monitored period of time exceeds a predetermined threshold io (e.g. the maximum age of the signal as implemented by control box 550), this can be indicative of a fault with the movable vanes. For example, the movable vanes 108 may have stopped moving and so are not registering as being fully opened or closed, or the actuating mechanisms 110 may have stopped reporting the status or position of the moveable vanes. The position of the movable vanes 108 may therefore be unknown by /5 the controller 102. The maximum allowed age of the signal is determined based on the movement time of the movable vanes 108, plus a nominal additional time to allow for signals to be transmitted to and from the actuating mechanisms 110 of the movable vanes 108.

When the input signals 112 are received after a period of time greater than the maximum allowed age of the signal, initialisation box 500 requests that the movable vanes 108 are calibrated. At the same time, control box 550 logs a fault and controller 102 determines that the movable vanes are in a closed position. In dependence on the one or more input signals 112 being received at a time after the maximum age of the signal has been exceeded, the controller 102 therefore selects the appropriate thermal brake model for determining an estimated temperature 120 of the vehicle brake 106 to be thermal brake model 114b. This approach assumes a vane closed scenario in the event of a delay in signals 112 being received at the controller 102 from components of the movable vane subsystem. In this way, the temperature of the vehicle brake 106 is not underestimated in the event of one or more signal delays.

In one example, the at least one signal associated with a status of one or more moveable vanes comprised within received input signals 112 indicates an error state of an over-temperature condition associated with the one or more moveable vanes. The 'associated' over-temperature condition may be any temperature based fault internal to the subsystem of the movable vanes 108, including a fault with the actuating mechanisms 110. For example, one or more motors controlling movement of the movable vanes 108 may have overheated, or may be too hot to allow sufficient control of one or more linkages of the actuating mechanism 110 to move the one or more moveable vanes. Such an over-temperature condition can be generalised to include any temperature condition which results in a reduction, or total loss, of the controller's ability to move one or more of the movable vanes 108.

To allow for an assessment of an over-temperature condition, the at least one signal associated with a status of one or more moveable vanes can comprise a status of the one or more actuating mechanisms 110, optionally, the status of the one or more actuating mechanisms 110 comprises a temperature of the one or more actuating mechanisms 110. Control box 560 can monitor the status of the one or more actuating mechanisms; for example, it can monitor the temperature directly or monitor a signal /5 associated with the temperature. If the signal, or a measured temperature of the actuating mechanism, is indicative of a fully operational state of the actuating mechanism, no change of the thermal model 114 is made by the controller 102. However, if the temperature of the actuating mechanism satisfies a predetermined criterion, for example exceeding a temperature threshold, this can be indicative of the actuating mechanism overheating, or approaching an over-temperature condition. In such an over-temperature condition, the actuating mechanism may be temporarily rendered inoperable.

Optionally, when the temperature threshold is first exceeded, the controller 102 can provide one or more output signals to control the actuating mechanism to open the movable vanes 108; in this way, should the actuating mechanism be unable to open the movable vanes 108 when required as a result of the overheating of the actuating mechanism, the movable vanes will have been pre-emptively opened to facilitate cooling of the vehicle brake 106. For example, controller 102 can be configured to generate one or more additional output signals 136, in dependence on the one or more input signals 112, to control the one or more actuating mechanisms 110 to adjust a position of the one or more moveable vanes 108 (see Figure 1A). The thermal brake model 104 can also be appropriately selected by the controller 102 to the thermal model 114a. If the temperature of the actuating mechanism subsequently falls below the temperature threshold, the movable vanes 108 may then be correspondingly closed by the controller 102 to reduce aerodynamic drag and improve efficiency of the vehicle.

If the controller 102 has not pre-emptively opened the movable vanes 108, or if no temperature signal is provided by the actuating mechanism, or if the actuating mechanism has been at an over-temperature condition for a sufficiently long period of time that the actuating mechanism is determined to be presently inoperable, an over-temperature error state is determined by the controller 102. Control box 560 may log a fault (for service) and controller 102 determines that the movable vanes are in a closed position. The controller 102 selects the appropriate thermal brake model for determining an estimated temperature 120 of the vehicle brake 106 to be thermal brake model 114b. In other words, the controller is configured to select the thermal brake model 114 in dependence on the temperature of the actuating mechanism satisfying a predetermined criterion (here exceeding a predefined temperature threshold, but other criteria are /5 anticipated depending on the configuration of the vehicle). This approach assumes a vane closed scenario in the event of an over-temperature fault of the actuating mechanism 110 of the movable vane 108. In this way, the temperature of the vehicle brake 106 is not underestimated in the event of an over-temperature fault.

In one example, the at least one signal associated with a status of one or more moveable vanes comprised within received input signals 112 indicates an error state of a blockage of the one or more moveable vanes. For example, a blockage may comprise a physical blockage (e.g. stones, snow, ice, or silt etc.) in contact with or otherwise impeding movement of the movable vanes 108, or any other blockage which prevents movement of the movable vanes 108 (for example, the movable vanes 108 being frozen in a closed position).

Such a blockage can occur in normal operation of the vehicle 100, and is not typically indicative of an error as such. To resolve the blockage, control box 570 controls the initialisation control box 500 to periodically request that the movable vanes 108 are calibrated; once the vanes have been successfully calibrated, normal operation movable vanes 108 can be resumed by control box 510, as described above. If successful calibration cannot be achieved, control box 570 logs a fault (for later service). If such a blockage condition is detected, the controller 102 determines that the vanes 108 are in a closed position. The controller 102 selects the appropriate thermal brake model for determining an estimated temperature 120 of the vehicle brake 106 to be thermal brake model 114b. In other words, the controller is configured to select the thermal brake model 114 in dependence on receipt of signals 112 indicating an error state is present and is caused by a blockage of the movable vanes 108. Controller 102 maintains thermal brake model 114b until successful calibration of the vanes 108, or removal of the blockage by other means, whereupon normal operation can be resumed by control box 510 of controller 102.

A method in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figure 6. Method 600 is a method for controlling an active brake system 104 of a vehicle 100, the active brake system comprising one or more moveable vanes 108 and a vehicle brake 106.

The method 600 comprises 610 receiving one or more input signals. The one or more /5 input signals here comprise at least one signal associated with a status of one or more moveable vanes 108 of vehicle 100. The method further comprises 620 optionally, controlling movement of the moveable vanes in dependence on the one or more input signals. For example, controlling 620, can comprise controlling, in dependence on the one or more input signals, one or more actuating mechanisms mechanically coupled to the moveable vanes 108 by one or more linkages to adjust a position of the one or more moveable vanes. The actuating mechanisms can be controlled by one or more output signals 136.

In one example, an over-temperature condition of the actuating mechanisms is indicated by the at least one signal (where the status of the one or more vanes comprises a temperature or a temperature related status of the one or more actuating mechanisms), and the one or more vanes may be pre-emptively opened by the controller 102 in dependence on the received one or more input signals. In another example, the received one or more input signals additionally or alternatively, indicate a wading mode of operation of the vehicle, and the one or more vanes may be pre-emptively opened by the controller 102 in dependence on the received one or more input signals in order to minimise stress/forces on the actuating mechanisms by attempting to open vanes 108 during the wading operation.

Method 600 further comprises 630 selecting a thermal (brake) model in dependence on the input signals. The thermal brake model is (an optionally empirical) thermal brake model 114 of the active brake system, and can be selected in dependence on the received one or more input signals. Method 600 further comprises 640 estimating a vehicle brake temperature using the thermal model. For example, estimating 640 can comprise determining an estimated temperature of the vehicle brake in dependence on the selected thermal brake model (i.e. the temperature of the vehicle brake is estimated using the thermal model). By selecting (630) a thermal brake model, optionally wherein the selecting comprises switching between a first thermal brake model and a second thermal brake model (where the first model corresponds to a thermal model of the vehicle brake when the one or more moveable vanes are in an open position, and the second model corresponds to a thermal model of the vehicle brake 106 when the one or more moveable vanes are in a closed position), an appropriate thermal model can be selected for the particular current position of the movable vanes, which can help facilitate improved estimation of the brake temperature.

In one example, the received one or more input signals at operation 610 comprise a signal indicative of a temperature of the one or more actuating mechanisms, wherein selecting (630) the thermal brake model comprises selecting the thermal brake model in dependence on the temperature satisfying a predetermined criterion. For example, the temperature of the actuating mechanisms may exceed a first temperature threshold. The temperature threshold may be the temperature at which the actuating mechanisms are rendered inoperable (in which case the controller may select the second model 114b associated with the closed movable vanes). Alternatively, the temperature threshold may be a temperature just below the temperature at which the actuating mechanisms are rendered inoperable (in which case the controller may control the movable vanes to move to an open position whilst the actuator is still able to control the actuators and select the first model 114a associated with the open movable vanes).

Method 600 further comprises 650 outputting one or more output signals to control the active brake system. Outputting 650 can comprise outputting in dependence on the estimated temperature of the vehicle brake. Method 600 further comprises 660, optionally, controlling the moveable vane(s) 108 in dependence on the one or more output signals (e.g. those output at operation 650). For example movement of the vanes 108 can be controlled to adjust a position of the vanes.

Method 600 can additionally or alternatively comprise 670 optionally, otherwise controlling an active brake system in dependence on the one or more output signals. For example, controlling 670, in dependence on the one or more output signals output at operation 650, the active brake system comprises controlling in a manner other than to move a position of the moveable vanes. For example, operation 670 can comprise providing feedback to a user of the vehicle. Operation 670 can optionally comprise, for example, controlling a fade warning assist system of the vehicle. For example, physical feedback can be provided to a user by controlling a pedal of the vehicle brake, and/or by io issuing a warning sound and/or by displaying a warning light.

It will be understood that the operations of method 600 may be performed in any suitable order, not necessarily in the order described herein. Moreover, one or more operations of method 600 can be repeated at any suitable time. The receipt of input signals by the /5 controller at operation 610 may be repeated without performance of the rest of method 600. Operation 610 may be repeated in combination with optional operation 620, or independent of the performance of operation 620, until a different thermal brake model needs to be selected at operation 630. Similarly, one or more operations of the method may be repeated after operations 620, 650, 660 and/or 670, as illustrated in Figure 6. In this way, the controller provides an active vehicle brake cooling system which utilises one or more feedback mechanisms to maintain the vehicle brake within an operating temperature range. Failure of the brakes due to overheating can therefore be reduced.

A vehicle 100 in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figure 7. This vehicle 100 may comprise any of the above described features of vehicle 100. This vehicle 100 comprises controller 102 and active brake system 104, which together form a system which may be arranged in such a way so as to implement method 600. In one embodiment, the vehicle 100 comprises one or more wading sensors 440 to indicate water and/or a depth of wading during a wading mode of operation.

It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

CLAIMS1. A controller for an active brake system of a vehicle, the active brake system comprising one or more moveable vanes and a vehicle brake system, the controller configured to: receive one or more input signals, the one or more input signals comprising at least one signal associated with a status of the one or more moveable vanes; select a thermal brake model of the active brake system in dependence on the received one or more input signals; ll,) determine an estimated temperature of the vehicle brake system in dependence on the selected thermal brake model; and output, in dependence on the estimated temperature, one or more signals to control the active brake system.
/5 2. The controller of claim 1, wherein the controller is configured to: control, in dependence on the one or more output signals, a fade warning assist system of the active brake system to provide feedback to a user of the vehicle.
3. The controller of claim 2, wherein the controller is configured to control a pedal of the vehicle brake system to provide the feedback.
4. The controller of any of claims 1 to 3, wherein the controller being configured to select a thermal brake model comprises the controller being configured to: switch between at least a first thermal brake model and a second thermal brake model, wherein the first model corresponds to a thermal model of the vehicle brake system when the one or more moveable vanes are in an open position, and wherein the second model corresponds to a thermal model of the vehicle brake system when the one or more moveable vanes are in a closed position.
5. The controller of claim 4, wherein the status of the one or more moveable vanes indicates that the one or more moveable vanes are in a closed position or that a position of the one or more moveable vanes is unknown, the controller being configured to select the second model in dependence on the status.
6. The controller of claim 4 or claim 5, wherein the status of the one or more moveable vanes indicates an error state of the one or more moveable vanes, the controller being configured to switch from the first model to the second model in dependence on the indicated error state.
7. The controller of claim 6, wherein the error state indicates at least one of: a supply voltage fault; a maximum age of the received one or more input signals; a blockage of the one or more moveable vanes; an over-temperature condition associated with the one or more moveable vanes; an electrical fault associated with the one or more moveable vanes; or a mechanical fault associated with the one or more moveable vanes.is
8. The controller of claim 6 or claim 7, wherein the controller is configured to calibrate the one or more moveable vanes in dependence on the error state.
9. The controller of any of claims 4 to 8, wherein the thermal brake model comprises a cooling model, and wherein a convective cooling contribution of the cooling model is reduced in the second model as compared to the first model.
10. The controller of any preceding claim, wherein the active brake system comprises one or more actuating mechanisms configured to adjust a position of the one or more moveable vanes.
1 1. The controller of claim 10, wherein the at least one signal associated with a status of the one or more moveable vanes is received from the one or more actuating mechanisms and indicates a current position of the one or more moveable vanes.
12. The controller of claim 10 or claim 11, wherein the controller is configured to: control, in dependence on the one or more output signals, the one or more actuating mechanisms to adjust a position of the one or more moveable vanes and/or control, via one or more additional output signals generated in dependence on the one or more input signals, the one or more actuating mechanisms to adjust a position of the one or more moveable vanes.
13. The controller of any of claims 10 to 12, wherein the at least one signal associated with a status of the one or more moveable vanes comprises a status of the one or more actuating mechanisms, wherein the controller is configured to select the thermal brake model in dependence on the status of the one or more actuating mechanisms.
14. The controller of claim 13, wherein the status of the one or more actuating mechanisms comprises a temperature of the one or more actuating mechanisms, wherein the controller is configured to select the thermal brake model in dependence on the temperature satisfying a predetermined criterion.
15. The controller of any of claims 10 to 14, wherein the received one or more input signals comprise a signal indicative of a wading mode of operation of the vehicle, wherein the controller is configured to control, in dependence on the signal indicative of a wading mode, the one or more actuating mechanisms to adjust a position of the one or more moveable vanes from a closed position to an open position.
16. A controller for an active brake system of a vehicle, the active brake system comprising one or more moveable vanes and a vehicle brake system, the controller configured to: receive one or more input signals indicative of a wading mode of operation of the vehicle, the one or more input signals received from a wading sensor and, optionally, received in dependence on direct user input; and output, in dependence on the one or more input signals, one or more signals configured to control a position of the one or more moveable vanes, wherein when the received one or more input signals from the wading sensor indicate a depth of wading is such that the one or more moveable vanes are not at least partially submerged, the output signals configured to control the one or more movable vanes to be in an open position, optionally, wherein, when the received one or more input signals from the wading sensor indicate a depth of wading is such that the one or more moveable vanes are at least partially submerged, the output signals are configured to control the one or more moveable vanes to remain in their current position.
17. A vehicle comprising: the controller of any preceding claim; and an active brake system comprising: one or more moveable vanes, one or more actuating mechanisms configured to adjust a position of the one or more moveable vanes, and a vehicle brake system.
18. The vehicle of claim 17, wherein the vehicle brake system is a brake by wire io vehicle brake system.
19. A method of controlling an active brake system of a vehicle, the active brake system comprising one or more moveable vanes and a vehicle brake system, the method comprising: receiving one or more input signals, the one or more input signals comprising at least one signal associated with a status of the one or more moveable vanes; selecting a thermal brake model of the active brake system in dependence on the received one or more input signals; determining an estimated temperature of the vehicle brake system in 20 dependence on the selected thermal brake model; and outputting, in dependence on the estimated temperature of the vehicle brake system, one or more signals to control the active brake system.
20. The method of claim 19, the method further comprising: controlling, in dependence on the one or more output signals. a fade warning assist system of the active brake system to provide feedback to a user of the vehicle.
21. The method of claim 19 or claim 20, wherein selecting a thermal brake model comprises: switching between a first thermal brake model and a second thermal brake model, wherein the first model corresponds to a thermal model of the vehicle brake system when the one or more moveable vanes are in an open position, and wherein the second model corresponds to a thermal model of the vehicle brake 35 system when the one or more moveable vanes are in a closed position.
22. The method of any of claims 19 to 21, wherein the active brake system comprises one or more actuating mechanisms configured to adjust a position of the one or more moveable vanes, and wherein the method further comprises: receiving, from the one or more actuating mechanisms, the at least one signal associated with a status of the one or more moveable vanes, wherein the at least one signal indicates a current position of the one or more moveable vanes; and controlling, in dependence on the one or more output signals, the one or more actuating mechanisms to adjust a position of the one or more moveable vanes.
23. The method of claim 22, wherein the received one or more input signals comprise a signal indicative of a wading mode of operation of the vehicle, the method further comprising: controlling, in dependence on the signal indicative of a wading mode of operation, the one or more actuating mechanisms to adjust a position of the one or more moveable vanes from a closed position to an open position.
24. The method of any claim 22 or 23, wherein the received one or more input signals comprise a signal indicative of a temperature of the one or more actuating mechanisms, wherein selecting the thermal brake model comprises: selecting the thermal brake model in dependence on the temperature satisfying a predetermined criterion.
25. A computer program comprising instructions that when executed by one or more hardware processors cause it or them to perform the method of any of claims 19 to 24.