A method for providing an assistive downhill braking function, vehicle and controller

Abstract

The present disclosure relates to a method of providing an assistive downhill braking function for a vehicle during drive off in a downhill condition. The method includes obtaining an angle of inclination of the slope in a direction of travel of the vehicle, obtaining an accelerator input value of a requested acceleration of the vehicle, obtaining a required braking force value to be requested in dependence of the obtained accelerator input value and the obtained angle of inclination of the slope, and increasing the requested braking force when determining that the accelerator input value decreases. This method enhances safety and control during downhill driving by automatically adjusting the braking force in response to changes in accelerator input and slope inclination.

Description

[0001] A method for providing an assistive downhill braking function, vehicle and controller

[0002] Field The technology relates to the field of automotive engineering related to vehicle control systems and braking assistance functions for improved safety, stability, and driving experience during downhill driving conditions and In particular when a vehicle drives off in a downhill condition. Background

[0003] Downhill driving, particularly in large vehicles such as trucks and buses, presents several challenges for drivers. One of the main challenges is controlling the vehicle's acceleration while driving downhill. This is especially important when the vehicle is required to stop and start frequently, such as in urban areas or during traffic congestion.

[0004] In conventional vehicles, the driver must manually control the acceleration and braking of the vehicle while driving downhill and especially when the vehicle starts from stationary. This typically involves simultaneously pressing the accelerator pedal and the brake pedal to maintain a desired speed and prevent the vehicle from rolling forward or accelerating too quickly. This method of controlling the vehicle's acceleration can be difficult and imprecise, leading to an increased risk of accidents and discomfort for the driver and passengers.

[0005] Various systems and methods have been proposed to assist drivers in controlling vehicle acceleration during downhill driving. For example, US 2019 / 0375411 discloses a method and system for controlling a vehicle during a downhill start, which provides for a smooth drive off. However, this prior art is primarily concerned with modifying the service brake pressure when starting in a downhill direction and does not address the challenges associated with controlling the vehicle’s acceleration at slow speeds or during manoeuvring.

[0006] Summary According to a first aspect of the disclosure, a method is provided for an assistive downhill braking function for a vehicle during drive off in a downhill condition. This method comprises obtaining an angle of inclination of a slope in a direction of travel of the vehicle, obtaining an accelerator input value of a requested acceleration of the vehicle, obtaining a required braking force value to be requested in dependence of the obtained accelerator input value and the obtained angle of inclination of the slope, and increasing the requested braking force when determining that the accelerator input value decreases. This method provides a saferand more controlled driving experience when descending a slope, as it automatically adjusts the braking force in response to changes in the accelerator input value and the slope's angle of inclination.

[0007] Optionally in some examples, the accelerator input value is obtained based on the obtained position of an accelerator pedal.

[0008] Optionally in some examples the accelerator input value is obtained based on a control signal received from an autonomous driving system and / or an assisted driving function.

[0009] Optionally in some examples, the required braking force value is obtained based on a first accelerator input threshold, and a second accelerator input threshold.

[0010] Optionally in some examples, when the requested acceleration of the vehicle is above the second accelerator input threshold, the assistive downhill braking function is deactivated.

[0011] Optionally in some examples, the required braking force value is obtained based on a third accelerator input threshold between the first accelerator input threshold, and the second accelerator input threshold wherein the third accelerator input threshold corresponds to a required braking force value that maintains a constant vehicle speed. This allows for maintaining the current speed of the vehicle without accelerating or decelerating at the third accelerator input threshold, providing a smoother and more comfortable driving experience. Optionally in some examples, when the requested acceleration of the vehicle is between the first accelerator input threshold and the third accelerator input threshold the vehicle undergoes deceleration. This ensures that the driver has precise control over the vehicle's acceleration at very low speeds, enhancing safety and stability during downhill driving.

[0012] Optionally in some examples, when the requested acceleration of the vehicle is between the third accelerator input threshold and the second accelerator input threshold the vehicle undergoes acceleration.

[0013] Optionally in some examples, a control instruction is sent to a braking system and / or a power train to request the required braking force value.

[0014] Optionally in some examples, the effect of the assistive downhill braking function is adjusted based on the obtained speed of the vehicle.

[0015] Optionally in some examples, the assistive downhill braking function has a full effect when the vehicle has a speed below a first speed threshold.

[0016] Optionally in some examples, the assistive downhill braking function has a reduced effect when the vehicle has a speed above the first speed threshold and below a second speed threshold. This allows for a gradual reduction in braking assistance as the vehicle's speed increases, providing a smoother and more natural driving experience.

[0017] Optionally in some examples, the assistive downhill braking function is deactivated when the vehicle has a speed above the second speed threshold. This prevents interference with natural acceleration at higher speeds, allowing for smooth and controlled driving experience.

[0018] Optionally in some examples, the required braking force value is adjusted based on the obtained weight of the vehicle. Optionally in same examples, if the vehicle is stationary, a brake hold is applied after the step of increasing the requested braking farce. Optionally, the brake hold is applied by at least one service brake.

[0019] Optionally in some examples, the step of increasing the requested braking farce occurs after a brake hold is disengaged. Optionally, the brake hold is disengaged by at least one service brake. This ensures a smooth transition from brake hold to downhill driving, enhancing the driving experience.

[0020] According to a second aspect of the disclosure, a vehicle is configured to perform the method of providing an assistive downhill braking function. The vehicle comprises a controller configured to obtain the angle of inclination of the slope, the accelerator input value, and a required braking force value to be requested, an accelerator input configured to provide information related to the accelerator input value to the controller, and a braking system and / or a powertrain configured to receive control instructions from the controller and adjust the braking force applied to the vehicle based on the received control instructions.

[0021] According to a third aspect of the disclosure, a computer program product comprises computer-readable instructions that, when executed by a processor of a controller in a vehicle, cause the controller to perform the method of providing an assistive downhill braking function.

[0022] According to a third aspect of the disclosure, a controller is configured to perform the method of providing an assistive downhill braking function. The controller comprises a processor configured to obtain the angle of inclination of the slope, the accelerator input value, and the required braking force, a memory storing calibration parameters for the assistive downhill braking function, an interface for receiving information related to the accelerator input value from an accelerator input, and an interface for sending control instructions to a braking system and / or a powertrain to adjust the braking force applied to the vehicle based on the obtained required braking force.

[0023] Brief Description of the Drawings Examples are described in more detail below with reference to the appended drawings. Figure 1 shows a schematic drawing of a vehicle with a direction of travel downhill, illustrating the ECU, brake control unit, service brakes, accelerator pedal, and inclinometer sensor according to an example.

[0024] Figure 2 shows a schematic representation of the vehicle and its subcomponents according to an example.

[0025] Figure 3 shows a response curve of brake force versus accelerator input of the vehicle according to an example.

[0026] Figure 4 shows a graph of the amount of the assistive downhill braking function applied in dependence on the speed of the vehicle according to an example.

[0027] Figure 5 shows a flow diagram of a first example of a method of applying an assistive downhill braking function according to an example.

[0028] Figure 6 shows a flow diagram of another example of an assistive downhill braking function according to an example.

[0029] Detoiied Description

[0030] Figure 1 illustrates a schematic diagram of a vehicle 100 equipped with an assistive downhill braking function. The vehicle 100 includes various components that work together to provide the assistive downhill braking function. These components include a controller 102, a braking system 104, an accelerator input 106, a wheel rotation sensor 108, a vehicle weight sensor 110, an inclination sensor 112, a CANBUS 114, and a powertrain 116.

[0031] In one example, the vehicle 100 is a motor vehicle, such as a car, truck, bus, or any other type of vehicle that is capable of being driven on a road or other surface. The vehicle 100 is equipped with various systems and components that enable it to operate and perform various functions. These systems and components include, but are not limited to, a powertrain 116, a braking system 104, an accelerator input 106, a controller 102, and various sensors such as a wheel rotation sensor 108, a vehicle weight sensor 110, and an inclination sensor 112. The vehicle 100 is also equipped with a CANBUS 114, which is a communication system that allows the various components and systems of the vehicle 100 to communicate with each other. In some implementations, the controller 102 is an electronic control unit (ECU) that is responsible for controlling various functions of the vehicle 100. The controller 102 includes a processor 118 and a memory 120. The processor 118 is configured to execute various instructions and algorithms stored in the memory 120 to control the operation of the vehicle 100.

[0032] The controller 102 is configured to obtain an angle of inclination of the slope 144 in a direction of travel of the vehicle 100, an accelerator input value 132 of a requested acceleration of the vehicle 100, and a required braking force value to be requested from the braking system 104 in dependence of the obtained accelerator input value 132 and the obtained angle of inclination of the slope 144. The controller 102 is also configured to increase the requested braking force when it determines that the accelerator input value 132 decreases.

[0033] By accurately determining the required braking force based on the accelerator input and the slope inclination, the controller 102 ensures that the vehicle 100 maintains a controlled speed, preventing sudden acceleration or deceleration that could potentially lead to rapid changes in acceleration, also known as “jerk”. The assistive downhill braking function enhances the safety of the vehicle 100, providing a more secure and comfortable driving experience for the driver and passengers.

[0034] The functions of the controller 102 in relation to the method of providing the assistive downhill braking function will be discussed below in reference to e.g. Figures 5 and 6.

[0035] In some configurations, the controller 102 is connected to the various components of the vehicle 100 via an interface to a CANBUS 114. The CANBUS 114 is a communication system that allows the various components and systems of the vehicle 100 to communicate with each other. The CANBUS 114 facilitates the exchange of data and control signals between the controller 102 and the other components of the vehicle 100. This enables the controller 102 to receive data from these components, such as the accelerator input value 132 from the accelerator input 106, the angle of inclination of the slope 144 from the inclination sensor 112, and the weight of the vehicle 100 from the vehicle weight sensor 110. The CANBUS 114 also enables the controller 102 to send control instructions to these components, such as a braking force request to the braking system 104 and / or the powertrain 116. Use of the powertrain 116 to generate the requested braking force e.g. via regenerative braking is discussed below in more detail.

[0036] The CANBUS 114 is designed to handle real-time data exchange, which is for the coordinated operation of the vehicle 100. The CANBUS 114 ensures that the data and control signals are transmited quickly and accurately between the controller 102 and the other components of the vehicle 100, which is for the smooth and efficient operation of the assistive downhill braking function.

[0037] In some implementations, the braking system 104 of the vehicle 100 includes service brakes 122, a braking control unit 124, and a hill hold control module 126. The service brakes 122 are configured to apply brake pressure to exert a braking force on one or more axles of the vehicle 100. The braking control unit 124 is configured to receive control instructions from the controller 102 and adjust the braking force applied by the service brakes 122 based on these instructions. The braking control unit 124 can also provide braking force by sending control instructions for a required engine torque from the powertrain 116. In some examples the braking system 104 preferably comprises the service brakes 122 to provide the requested braking force. However, in other in other examples the braking system 104 is not limited to service brakes 122. Indeed, the braking system 104 can comprise any mechanism, component or system which is configured to generate a braking force on the vehicle 100. This can include, but is not limited to a parking brake (not shown), the powertrain 116, engine, electric motor, transmission etc.

[0038] The hill hold control module 126 is configured to receive control instructions from the braking control unit 124 and control the service brakes 122 to adjust the braking force to increase braking pressure for hill hold. This is also known as a brake hold. This ensures that the vehicle 100 remains stationary when it is stopped on a slope 144, enhancing the safety and stability of the vehicle 100. However, in other examples, the braking force required for a hill hold can be provided by any suitable mechanism configured to generate a braking force. For example, alternatively or additionally a parking brake (not shown) can be used to provide a braking force for a hill hold. The braking system 104 plays a role in the operation of the assistive downhill braking function. When the controller 102 determines that the accelerator input value 132 decreases, it sends a control instruction to the braking system 104 to increase the requested braking force. This helps to maintain or decrease the speed of the vehicle 100 and prevent it from accelerating too quickly when it is driving downhill, if required.

[0039] In contrast, when the controller 102 determines that the accelerator input value 132 increases, it sends a control instruction to the braking system 104 to decrease the requested braking force. This feature is particularly beneficial in scenarios where the vehicle 100 is transitioning from a steep downhill slope to a less steep slope or a fiat surface, where full braking assistance may no longer be necessary. This will be discussed in more detail below in reference to e.g. Figures 5 and 6.

[0040] In addition, the controller 102 is also capable of determining a requested braking force from the braking system 104 to maintain the speed of the vehicle 100. This function is particularly useful since the vehicle 100 is more easily driven downhill at a constant speed. By maintaining the speed of the vehicle 100, the controller 102 can provide a smooth and controlled driving experience for the driver, reducing the need for the driver to constantly adjust the accelerator input or brake input. Again, this will be discussed in more detail below in reference to e.g. Figures 5 and 6.

[0041] In some configurations, the accelerator input 106 of the vehicle 100 includes an accelerator pedal 128 and a pedal position sensor 130. The accelerator pedal 128 is used by the driver to indicate how much acceleration is requested. The pedal position sensor 130 is configured to measure the physical position of the accelerator pedal 128 and send this information to the controller 102 via the CANBUS 114.

[0042] As mentioned below, whilst the examples with reference to Figures 1 to 6 discuss that the accelerator input value 132 is the position of the accelerator pedal 128, the accelerator input value 132 can be obtained from any suitable input source. For example, the controller 102 can obtain the accelerator input value 132 from a robotic controller (not shown) of the vehicle 100. For example, the accelerator input value 132 can be obtained from an autonomous driving system and / or an assisted driving function connected to the vehicle 100. Alternatively, the accelerator input value 132 can be received remotely by the controller 102 for example from a remote operator.

[0043] The controller 102 obtains the accelerator input value 132 based on the position information received from the pedal position sensor 130. The accelerator input value 132 indicates how much acceleration is requested by the driver. The controller 102 uses this information to determine the required braking force value to be requested from the braking system 104.

[0044] In some implementations, the vehicle 100 is equipped with a wheel rotation sensor 108. The wheel rotation sensor 108 is configured to measure the rotational speed of the wheels of the vehicle 100. The wheel rotation sensor 108 provides this data to the controller 102 via the CAN BUS 114. The controller 102 uses the data from the wheel rotation sensor 108 to determine the speed of the vehicle 100. In some other examples, the controller 102 can determine the speed of the vehicle 100 from one or more other sources e.g. a GPS system.

[0045] The speed of the vehicle 100 is a factor in the operation of the assistive downhill braking function. The controller 102 optionally adjusts the effect of the assistive downhill braking function based on the speed of the vehicle 100 as discussed in more detail below.

[0046] In some configurations, the vehicle 100 optionally includes a vehicle weight sensor 110. The vehicle weight sensor 110 is configured to measure the weight of the vehicle 100 and send this information to the controller 102 via the CAN BUS 114. The controller 102 uses the weight information from the vehicle weight sensor 110 to determine an additional required braking force value to be requested from the braking system 104 due to the weight of the vehicle 100 and the determined angle of inclination of the slope 144.

[0047] The weight of the vehicle 100 is a factor in the operation of the assistive downhill braking function. A heavier vehicle 100 may require a greater braking force to maintain a constant speed when driving downhill. By taking into account the weight of the vehicle 100, the controller 102 can request an appropriate braking force from the braking system 104 to ensure a smooth and controlled downhill drive. Alternatively, the controller 102 can obtain the weight information of the vehicle 100 via alternative sources, for example the weight of the vehicle 100 may be stored in memory 120. Alternatively, the braking control unit 124 may separately determine, calculate, or otherwise obtain the weight of the vehicle 100 separately and send this to the controller 102.

[0048] In some implementations, the vehicle 100 optionally includes an inclination sensor 112. The inclination sensor 112 is configured to determine an angle of inclination of the slope 144 in the direction of travel of the vehicle 100. The inclination sensor 112 sends this information to the controller 102 via the CANBUS 114. The controller 102 uses the angle of inclination information from the inclination sensor 112 to determine the required braking force value to be requested from the braking system 104.

[0049] The angle of inclination of the slope 144 is a factor in the operation of the assistive downhill braking function. A steeper slope 144 may require a greater braking force to maintain a constant speed when driving downhill. By taking into account the angle of inclination of the slope 144, the controller 102 can request an appropriate braking force from the braking system 104 to ensure a smooth and controlled downhill drive.

[0050] In some alternative examples, the inclination of the slope 144 is determined via alternative sources. For example, the angle of inclination of the slope 144 can be determined from a geographical database stored in the memory 120.

[0051] In some implementations, the powertrain 116 of the vehicle 100 includes an engine. The engine is a component of the powertrain 116 that provides the power needed to drive the vehicle 100. The engine can be any type of engine suitable for use in a vehicle 100, such as a gasoline engine, a diesel engine, a hybrid engine, or an electric motor.

[0052] The engine optionally is used in the operation of the assistive downhill braking function. In some configurations, the braking control unit 124 is configured to additionally or alternatively obtain a braking force from engine torque or other drive train forces. This can help to slow down the vehicle 100 when it is driving downhill, reducing the need for the service brakes 122 to apply brake pressure. For example, regeneration in an electric motor can be used additionally or alternatively to exert a braking force for the assistive downhill braking function. Indeed any suitable retardation arrangement can be used to exert a braking force for the assistive downhill braking function.

[0053] In some implementations, the powertrain 116 of the vehicle 100 includes a transmission. The transmission is a component of the powertrain 116 that transmits the power generated by the engine to the wheels of the vehicle 100. The transmission can be any type of transmission suitable for use in a vehicle 100, such as a manual transmission, an automatic transmission, or a continuously variable transmission (CVT).

[0054] The transmission optionally is used in the operation of the assistive downhill braking function. In some configurations, the braking control unit 124 is configured to additionally or alternatively provide braking force from engine torque by selecting a particular gear in the transmission.

[0055] In some configurations, the memory 120 stores calibration parameters for the assistive downhill braking function and the vehicle 100 speed response curve. These calibration parameters can include, for example, a first speed threshold (v_offramp) 140, and a second speed threshold (y_pff) 142. These calibration parameters are discussed in more detail with respect to Figures 3 and 4 below. Figure 3 shows a response curve of brake force versus accelerator input value 132 of the vehicle 100 according to an example. Figure 4 illustrates a graph of the amount of the assistive downhill braking function applied in dependence on the speed of the vehicle 100 according to an example.

[0056] The controller 102 uses these calibration parameters to determine the effect of the assistive downhill braking function based on the speed of the vehicle 100. For example, the assistive downhill braking function may have a full effect when the vehicle 100 has a speed below the first speed threshold 140, a reduced effect when the vehicle 100 has a speed above the first speed threshold 140 and below a second speed threshold 142, and may be deactivated when the vehicle 100 has a speed above the second speed threshold 142. When the vehicle 100 has a speed beiow the first speed threshold (v__offramp) 140, the assistive downhill braking function has a full effect. This means that the assistive downhill braking function is fully engaged and provides maximum assistance to the driver when the speed of the vehicle 100 is below this threshold. This feature is particularly beneficial in scenarios where the vehicle 100 is starting to descend a steep slope 144 from a stationary position, as it helps to control the speed of the vehicle 100 and prevent it from accelerating too quickly. By adjusting the effect of the assistive downhill braking function based on the speed of the vehicle 100, the controller 102 can provide a smooth and controlled driving experience for the driverand passengers. This will be discussed in mere detail below with respect to Figures 5 and 6. in some configurations, the memory 120 stores calibration parameters for the braking force and the accelerator input 106 response curve (e.g. as shown in Figure 3). These calibration parameters can include, for example, a first accelerator input threshold 134, a second accelerator input threshold 136, and a third accelerator input threshold 138.

[0057] The controller 102 uses these calibration parameters to determine the braking force (BFhold) to be requested from the braking system 104 based on the accelerator input value 132. For example, the controller 102 may request a braking force that is sufficient to stop and hold the vehicle 100 when the accelerator input value 132 is at the first accelerator input threshold 134. The controller 102 may alternatively request a braking force (BFequal) that is sufficient to maintain the current speed of the vehicle 100 without accelerating or decelerating when the accelerator input value 132 is at the third accelerator input threshold 138. The controller 102 may alternatively further request no braking force (BFOff) when the accelerator input value 132 is above the second accelerator input threshold 136.

[0058] In addition, the controller 102 is also configured to modify the assistive downhill braking function based on both the speed as discussed in reference to Figure 4 and the accelerator input value 132 as discussed in reference to Figure 3. This is discussed in detail with respect to Figure 6 below. in some examples, the controller 102 may be configured to modify the assistive downhill braking function based on the accelerator input value 132 as discussed in reference to Figure 3. in this case the modification of the assistive downhili braking function is not based on the speed of the vehicle 100. in some implementations, the braking system 104 of the vehicle 100 includes service brakes 122. The service brakes 122 are configured to apply brake pressure to exert a braking force on one or more axles of the vehicle 100. The service brakes 122 can be any type of brakes suitable for use in the vehicle 100, such as disc brakes, drum brakes, or regenerative brakes. In some examples, the service brakes 122 may solely provide the braking force for the assistive downhill braking function. In other examples, additionally or alternatively, the powertrain 116 can provide the braking force for the assistive downhill braking function.

[0059] In some configurations, the accelerator input 106 of the vehicle 100 includes an accelerator pedal 128. The accelerator pedal 128 is used by the driver to indicate how much acceleration is requested. The accelerator pedal 128 can be any type of accelerator pedal 128 suitable for use in the vehicle 100, such as a mechanical pedal, an electronic pedal, or a pedal with a position sensor.

[0060] When the driver presses the accelerator pedal 128, the pedal position sensor 130 measures the physical position of the accelerator pedal 128 and sends this information to the controller 102 via the CAN BUS 114. The controller 102 uses this information to determine the accelerator input value 132, which indicates how much acceleration is requested by the driver.

[0061] In some implementations, the accelerator input 106 of the vehicle 100 includes a pedal position sensor 130. The pedal position sensor 130 is configured to measure the physical position of the accelerator pedal 128 and send this information to the controller 102 via the CANBUS 114. The pedal position sensor 130 can be any type of sensor suitable for measuring the position of a pedal, such as a potentiometer, a Hall effect sensor, or an optical sensor.

[0062] When the driver presses the accelerator pedal 128, the pedal position sensor 130 measures the physical position of the accelerator pedal 128 and sends this information to the controller 102 via the CAN BUS 114. The controller 102 uses this information to determine the accelerator input value 132, which indicates how much acceleration is requested by the driver.

[0063] Figure 2 illustrates a schematic diagram of the controller 102 of the vehicle 100 and the vehicle 100 will be discussed in more detail with respect to Figure 2.

[0064] As shown in Figure 2, in some implementations, the braking system 104 of the vehicle 100 includes a hill hold control module 126. The hill hold central module 126 is configured to receive control instructions from the braking control unit 124 and control the service brakes 122 to adjust the braking force (BFhold) to increase braking pressure for hill hold. This ensures that the vehicle 100 remains stationary when it is stopped on a slope 144, enhancing the safety and stability of the vehicle 100.

[0065] When the controller 102 determines that the vehicle 100 is stationary and the accelerator input value 132 is below a certain threshold, it sends a control instruction to the hill hold control module 126 to apply a brake hold. This prevents the vehicle 100 from rolling forward on the slope 144 (when the vehicle is facing downhill), providing greater control and convenience for the driver.

[0066] In some configurations, the braking system 104 of the vehicle 100 includes a braking control unit 124. The braking control unit 124 is configured to receive control instructions from the controller 102 and adjust the braking force applied by the service brakes 122 based on these instructions. The braking control unit 124 can also provide braking force from engine torque or other drive train forces. Alternatively, the controller 102 can perform the function of the braking control unit 124. In this way, in some examples, there is no separate braking control unit 124. In some examples, the braking control unit 124 can determine the required braking force based on a control instruction received from the controller 102. Alternatively, the braking control unit 124 can receive the required braking force from the controller 102 in the control instruction.

[0067] As mentioned above, figure 3 shows a response curve of brake force versus accelerator input value 132 of the vehicle 100 according to an example. The accelerator input value 132 indicates how much acceleration is requested by the driver. The controller 102 obtains the accelerator input value 132 based on the position information received from the pedal position sensor 130.

[0068] The controller 102 uses the accelerator input value 132 to determine the required braking force value to be requested from the braking system 104. If the accelerator input value 132 decreases, indicating that the driver is requesting less acceleration, the controller 102 increases the requested braking force to slow down the vehicle 100. This helps to maintain the speed of the vehicle 100 and prevent it from accelerating too quickly when it is driving downhill.

[0069] In some implementations, the accelerator input value 132 is a numerical value that represents the amount of acceleration requested by the driver. The accelerator input value 132 is determined based on the position of the accelerator pedal 128, which is measured by the pedal position sensor 130. The pedal position sensor 130 sends the position information of the accelerator pedal 128 to the controller 102 via the CAN BUS 114, and the controller 102 uses this information to determine the accelerator input value 132.

[0070] Whilst the examples with reference to Figures 1 to 6 discuss that the accelerator input value 132 is the position of the accelerator pedal 128, the accelerator input value 132 can be obtained from any suitable input source. For example, the controller 102 can obtain the accelerator input value 132 from a robotic controller (not shown) of the vehicle 100. For example, the accelerator input value 132 can be obtained from an autonomous driving system and / or an assisted driving function connected to the vehicle 100. Alternatively, the accelerator input value 132 can be received remotely by the controller 102 for example from a remote operator.

[0071] In some configurations, the controller 102 uses a first accelerator input threshold 134 to determine the braking force (BFhoSd) to be requested from the braking system 104. The first accelerator input threshold 134 is a predetermined value that represents a certain level of acceleration requested by the driver. The first accelerator input threshold 134 is stored in the memory 120 of the controller 102. When the accelerator input value 132 is at the first accelerator input threshold 134, the controller 102 determines that the braking force (BFhold) to be requested from the braking system 104 should be sufficient to stop and hold the vehicle 100. This ensures that the vehicle 100 remains stationary when the driver is not requesting any acceleration, enhancing the safety and stability of the vehicle 100.

[0072] In some examples, the first accelerator input threshold 134 can be set to different values within the specified range of 1 -5% of the maximum accelerator input value 132. For instance, in one example, the first accelerator input threshold 134 can be set to 1% of the maximum accelerator input value 132.

[0073] In another example, the first accelerator input threshold 134 can be set to e.g. 2%, 3%, 4% of any other suitable value of the maximum accelerator input value 132.

[0074] In some implementations, the controller 102 uses a second accelerator input threshold 136 to determine the braking force (BFOff) to be requested from the braking system 104. The second accelerator input threshold 136 is a predetermined value that represents a certain level of acceleration requested by the driver. The second accelerator input threshold 136 is stored in the memory 120 of the controller 102.

[0075] When the accelerator input value 132 is above the second accelerator input threshold 136, the controller 102 determines that no braking force needs to be requested from the braking system 104. This allows the vehicle 100 to accelerate without any interference from the assistive downhill braking function, providing a smooth and controlled driving experience for the driver. This is shown in Figure 6 in step S220.

[0076] In some examples, the second accelerator input threshold 136 can be set to different values within the specified range of 20 to 30% of the maximum accelerator input value 132. For instance, in one example, the second accelerator input threshold 136 can be set to 20% of the maximum accelerator input value 132.

[0077] In another example, the second accelerator input threshold 136 can be set to 30% of the maximum accelerator input value 132. This would provide a slightly slower response time for the deactivation of the assistive downhill braking function, which may be preferred in certain driving conditions or for certain driver preferences, in some configurations, the controller 102 uses a third accelerator input threshold 138 to determine the braking force (BFequal) to be requested from the braking system 104. The third accelerator input threshold 138 is a predetermined value that represents a certain level of acceleration requested by the driver. The third accelerator input threshold 138 is stored in the memory 120 of the controller 102.

[0078] When the accelerator input value 132 is at the third accelerator input threshold 138, the controller 102 determines that the braking force (BFequal) to be requested from the braking system 104 should be sufficient to maintain the current speed of the vehicle 100 without accelerating or decelerating. This allows the vehicle 100 to maintain a constant speed when the driver is requesting a certain level of acceleration, providing a smooth and controlled driving experience for the driver.

[0079] In some examples, the third accelerator input threshold 138 can be set to different values within the specified range of 5% of the maximum accelerator input value 132. For instance, in one example, the third accelerator Input threshold 138 can be set to 5% of the maximum accelerator input value 132. This would mean that the assistive downhill braking function would maintain the current speed of the vehicle 100 when the accelerator input value 132 is at this threshold, providing a high level of control for the driver.

[0080] The values for the first accelerator input threshold 134, second accelerator input threshold 136, and the third accelerator input threshold 138 can be set to any suitable value. For example, these thresholds can be changed depending on the parameters of the vehicle 100, the road surface, weather, surface water or any other factor affecting the vehicle 100.

[0081] The method of providing the assistive downhill braking function will now be discussed in more detail with respect to Figures 5 and 6. Figure 5 illustrates a flowchart of a method for determining the effect of the assistive downhill braking function based on the speed of the vehicle 100.

[0082] The method includes several steps that are executed by the controller 102 of the vehicle 100. These steps include obtaining an inclination of the downhill slope 144 in the direction of travel of the vehicle 100 as shown in step S200. The controller 102 then obtains an accelerator input value 132 as shown in step S202. The controller 102 then obtains the required braking force value to be requested from the braking system 104 in dependence the obtained accelerator input value 132 as shown in step S204. The controller 102 then determines the effect of the assistive downhill braking function. As shown in step S206, the braking force is increased in dependence of determining that the accelerator input value 132 has decreased. This means that the driver can more easily control the vehicle 100 with only the accelerator pedal 128 when driving the vehicle 100 off in a downhill condition.

[0083] Figure 6 illustrates another flowchart of a method for determining the required braking force value to be requested from the braking system 104 based on the accelerator input value 132.

[0084] In some implementations, the controller 102 of the vehicle 100 is configured to obtain an angle of inclination of the slope 144 in a direction of travel of the vehicle 100 as shown in step S200. The controller 102 optionally obtains this information from the inclination sensor 112, which is configured to measure the angle of inclination of the slope 144. The inclination sensor 112 sends this information to the controller 102 via the CANBUS 114.

[0085] The controller 102 uses the angle of Inclination of the slope 144 to determine the required braking force value to be requested from the braking system 104.

[0086] The controller 102 is configured to optionally activate the assistive downhill braking function if the angle of Inclination of the slope 144 is above the threshold angle. This means that when the vehicle 100 is on a slope 144 that is steeper than the threshold angle as shown in step S208, the assistive downhill braking function is activated as shown in step S210. This feature enhances the safety and stability of the vehicle 100, especially when it is driving downhill on steep slopes 144. If the controller 102 determines that the angle of inclination of the slope 144 is below the threshold angle in step S208. the assistive downhill braking function remains deactivated and the controller 102 continues to monitor the angle of inclination of the slope 144 as shown in step S212.

[0087] The threshold angle is a predetermined value that represents a certain level of the slope 144. The threshold angle is stored in the memory 120 of the controller 102. In some examples, the threshold angle is 1 degree. In some other examples, the threshold value is 2 degrees, 3 degrees or any other suitable angle. The threshold angle can be determined based on the parameters of the vehicle 100.

[0088] In some examples, steps S208, S210, S212 can be optional, and the assistive downhill braking function can be always on.

[0089] In some implementations, the controller 102 of the vehicle 100 is configured to continuously monitor the angle of inclination of the slope 144 during operation of the assistive downhill braking function. The controller 102 obtains this inclination information and modifies the requested braking force.

[0090] The controller 102 is also configured to release a brake hold in step S214 in response to a determined accelerator input value 132 as shown in step S216. When the controller 102 determines that the accelerator input value 132 is above a certain threshold e.g. the first accelerator input threshold 134, the controller 102 sends a control instruction to the braking system 104 to release the brake hold. This allows the vehicle 100 to start moving.

[0091] In some implementations, the controller 102 of the vehicle 100 is configured to determine the accelerator input value 132 based on the position of the accelerator pedal 128 as shown in steps S202, S218. The accelerator pedal 128 is used by the driver to indicate how much acceleration is requested. The pedal position sensor 130 is configured to measure the physical position of the accelerator pedal 128 and send this information to the controller 102 via the CANBUS 114. The pedal position sensor 130 is configured to measure the physical position of the accelerator pedal 128 and send this information to the controller 102 via the CANBUS 114 as shown in step S218. The controller 102 uses this information to determine the accelerator input value 132, which indicates how much acceleration is requested by the driver.

[0092] The controller 102 uses the position information from the pedal position sensor 130 to determine the accelerator input value 132 as shown in steps S220. S230 and S226. The controller 102 uses the previously mentioned calibration parameters to determine the required braking force value to be requested from the braking system 104 based on the accelerator input value 132.

[0093] In step S220 the controller 102 determines that the accelerator input value 132 is above the second accelerator input threshold 136 and no braking force (BFOff) is required. This means that the vehicle 100 will accelerate normally since the assistive downhill braking function is deactivated as shown in step S244.

[0094] In step S230 the controller 102 determines that the accelerator input value 132 is between the third accelerator input threshold 138 and the second accelerator input threshold 136. This means that the vehicle 100 will accelerate gradually.

[0095] In step S226 the controller 102 determines that the accelerator input value 132 is between the third accelerator input threshold 138 and the first accelerator input threshold 134. This means that the vehicle 100 will decelerate.

[0096] In step S222 the controller 102 determines that the accelerator input value 132 is at the third accelerator input threshold 138 which corresponds to a braking force (BFequal) that is sufficient to maintain the current speed of the vehicle 100 without accelerating or decelerating. When the accelerator input value 132 is equal to third accelerator input threshold 138, the current braking force is maintained, and the speed remains constant as shown in step S224.

[0097] In some implementations, the controller 102 of the vehicle 100 is configured to obtain a required braking force value to be requested from the braking system 104 in dependence of the obtained accelerator input value 132 and the obtained angle of inclination of the slope 144 discussed in reference to steps S22Q, S222, S226 and S230. The controller 102 uses the accelerator input value 132 and the angle of inclination of the slope 144 to determine the required braking force value to be requested from the braking system 104.

[0098] The controller 102 uses various algorithms and calibration parameters stored in the memory 120 to determine the braking force. These algorithms and calibration parameters take into account various factors, such as the speed of the vehicle 100, the weight of the vehicle 100, and the angle of inclination of the slope 144. By taking into account one or more of these factors, the controller 102 can accurately determine the required braking force value to be requested from the braking system 104 to ensure a smooth and controlled downhill drive.

[0099] In some configurations, the controller 102 of the vehicle 100 is configured to increase the requested braking force in step S206 when the controller 102 determines that the accelerator input value 132 decreases as shown in step S226. The controller 102 then sends a control instruction to the braking system 104 to increase the requested braking force as shown in step S232.

[0100] Increasing the requested braking force helps to slow down the vehicle 100 and prevent it from accelerating too quickly when the vehicle 100 is driving downhill. This enhances the safety and comfort of the driver and passengers, especially when the vehicle 100 is driving downhill.

[0101] In some configurations, the controller 102 of the vehicle 100 is configured to decrease the requested braking force as shown in step S228 when the controller 102 determines that the accelerator input value 132 increases in step S230. The controller then sends a control instruction to the braking system 104 to decrease the requested braking force as shown in step S232.

[0102] Decreasing the requested braking force allows the vehicle 100 to accelerate without any interference from the assistive downhill braking function. This provides a smooth and controlled driving experience for the driver, especially when the vehicle 100 is driving downhill.

[0103] The control instruction sent in step S232 includes information about the requested braking force, which is determined by the controller 102 based on the accelerator input value 132 and the angle of inclination of the slope 144. The control instruction may be a requested braking force, requested deceleration or a requested speed from the braking control unit 124. The braking system 104 receives the control instruction and adjusts the braking force applied to the vehicle 100 based on the requested braking force.

[0104] In some configurations, the controller 102 of the vehicle 100 is optionally configured to determine an additional required braking force value to be requested from the braking system 104 due to the weight of the vehicle 100 and the determined angle of inclination of the slope 144. The controller 102 optionally obtains the weight of the vehicle 100 from the vehicle weight sensor 110 or from parameters stored in the memory 120. The controller 102 also obtains the angle of inclination of the slope 144 from the inclination sensor 112 or from information received from the braking control unit 124. The controller 102 optionally uses the weight of the vehicle 100 and the angle of inclination of the slope 144 to determine the additional required braking force value to be requested from the braking system 104, The additional braking force helps to slow down the vehicle 100 and prevent it from accelerating too quickly when it is driving downhill, especially when the vehicle 100 is heavy or the slope 144 is steep.

[0105] In some implementations, the controller 102 of the vehicle 100 is configured to obtain the speed of the vehicle 100. The controller 102 obtains the speed of the vehicle 100 from the wheel rotation sensor 108, which is configured to measure the rotational speed of the wheels of the vehicle 100. The wheel rotation sensor 108 sends this information to the controller 102 via the CAN BUS 114.

[0106] In some implementations, the controller 102 of the vehicle 100 is configured to determine the speed of the vehicle 100 based on data received from the wheel rotation sensor 108. The controller 102 is configured to determine that when the vehicle 100 has a speed above a first speed threshold (vjcfframp) 140 and below a second speed threshold (v_pff) 142, the assistive downhill braking function has a reduced effect as shown in step S236. The percentage effect of the assistive downhill braking function decreases from 100% at the first speed threshold (v_pfframp) 140 to 0% at a second speed threshold (v_off) 142. As shown in Figure 4, the decrease in the effect of the assistive downhill braking function is linear, but the reduction in effect can be nonlinear between the first speed threshold (v offramp) 140 and a second speed threshold (v_pff) 142.

[0107] This means that as the vehicle 100 speed increases beyond the first speed threshold 140 but remains below the second speed threshold 142, the assistive downhill braking function gradually reduces its effect. This allows for a smooth transition from full braking assistance to reduced braking assistance, providing a more comfortable and controlled driving experience for the driver.

[0108] The controller 102 is also configured to determine that when the vehicle 100 has a speed below a first speed threshold (v_offramp) 140 the assistive downhill braking function has a full effect as shown in step S234. For example, below a first speed threshold (v_pfframp) 140 the assistive downhill braking function has 100% effect.

[0109] Furthermore, the controller 102 is configured to disable the assistive downhill braking function completely as shown in step S244 when the speed of the vehicle 100 exceeds the second speed threshold (v ..off) 142 as shown in steps S238. This means that when the speed of the vehicle 100 is above the second speed threshold 142, the assistive downhill braking function is turned off, allowing the vehicle 100 to accelerate without any interference from the assistive downhill braking function. As mentioned above, the controller 102 is configured to also disable the assistive downhill braking function completely when the accelerator input value 132 is above the second accelerator input threshold 136 as shown in step S220.

[0110] In some examples, the first speed threshold (v...offramp) 140 is typically set to a value in a range between less than 5 kph and greater than 0 kph. For instance, the first speed threshold (v_offramp) 140 could be set to 4 kph. In some configurations, the second speed threshold (v_pff) 142 is typically sei to a value greater than the first speed threshold (vjrfframp) 140 and less than 10 kph. For example, the second speed threshold (v__pff) 142 could be set to 7 kph.

[0111] The values for the first speed threshold 140, and the second speed threshold 142 can be set to any suitable value. For example, these thresholds can be changed depending on the parameters of the vehicle 100, the road surface, weather, surface water or any other factor affecting the vehicle 100.

[0112] In some implementations, the controller 102 of the vehicle 100 is configured to determine if the vehicle 100 is stationary as shown in step S240 and apply a brake hold by at least one service brake 122 as shown in step S242. Once the vehicle 100 is back in a brake hold, the controller 102 can perform the assistive downhill braking function again by returning to step S216 when the driver next uses the accelerator pedal 128.

[0113] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and ’’the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and / or ’’including" when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and / or groups thereof. it will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure. Relative terms such as "below" or "above” or "upper" or "tower" or "horizontal" or "vertical” may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0114] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealised or overly formal sense unless expressly so defined herein.

[0115] It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims, in the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the disclosure being set forth in the following claims.

Claims

Claims1. A method of providing an assistive downhill braking function for a vehicle (100) during drive off in a downhill condition, the method comprising: obtaining an angle of inclination of a slope (144) in a direction of travel of the vehicle (100) [S200]: obtaining an accelerator input value (132) of a requested acceleration of the vehicle (100) [S202]; obtaining a required braking force value to be requested in dependence of the obtained accelerator input value (132) and the obtained angle of inclination of the slope (144) [S204]; and increasing the requested braking force when determining that the accelerator input value (132) decreases [S206].

2. The method according to claim 1 , further obtaining the accelerator input value (132) based on the obtained position of an accelerator pedal (128).

3. The method according to claims 1 or 2, further obtaining the accelerator input value (132) based on a control signal received from an autonomous driving system and / or an assisted driving function.

4. The method according to any of the preceding claims, further comprising obtaining the required braking force value based on a first accelerator input threshold (134), and a second accelerator input threshold (136).

5. The method according to claim 4 wherein when the requested acceleration of the vehicle (100) is above the second accelerator input threshold (136), the assistive downhill braking function is deactivated.

6. The method of claims 4 or 5 wherein further comprising obtaining the required braking force value based on a third accelerator input threshold (138) between the first accelerator input threshold (134), and the second accelerator input threshold (136) wherein the third accelerator input threshold (138) corresponds to a required braking force value that maintains a constant vehicle speed.

7. The method of claims 6 wherein when the requested acceleration of the vehicle (100) is between the first accelerator input threshold (134) and the third accelerator input threshold (138) the vehicle (100) undergoes deceleration.

8. The method of claims 6 or 7 wherein when the requested acceleration of the vehicle (100) is between the third accelerator input threshold (138) and the second accelerator input threshold (136) the vehicle (100) undergoes acceleration.

9. The method according to any of the preceding claims, further comprising sending a control instruction to a braking system (104) and / or a powertrain (116) to request the required braking force value.

10. The method according to any of the preceding claims, further comprising obtaining a speed of the vehicle (100) and adjusting the effect of the assistive downhill braking function based an the obtained speed.

11. The method according to claim 10. wherein the assistive downhill braking function has a full effect when the vehicle (100) has a speed below a first speed threshold (140).

12. The method according to claims 10 or 11 , wherein the assistive downhill braking function has a reduced effect when the vehicle (100) has a speed above the first speed threshold (140) and below a second speed threshold (142).

13. The method according to any of claims 10 to 12, wherein the assistive downhill braking function is deactivated when the vehicle (100) has a speed above the second speed threshold (142).

14. The method according to any of the preceding claims, further comprising obtaining a weight of the vehicle (100) and adjusting the required braking force value based on the obtained weight.

15. The method according to any of the preceding claims, further comprising determining if the vehicle (100) is stationary and applying a brake hold after the step of increasing the requested braking force16. The method according to any of the preceding claims wherein the step of increasing the requested braking force occurs after a brake hold is disengaged.

17. A vehicle (100) configured to perform the method according to any of claims 1 to 16, the vehicle (100) comprising: a controller (102) configured to obtain the angle of inclination of the slope (144), the accelerator input value (132), and a required braking force value to be requested; an accelerator input (106) configured to provide information related to the accelerator input value (132) to the controller (102); and a braking system (104) and / or a powertrain (116) configured to receive control instructions from the controller (102) and adjust the braking force applied to the vehicle (100) based on the received control instructions.

18. A computer program product comprising computer-readable instructions that, when executed by a processor (118) of a controller (102) in a vehicle (100), cause the controller (102) to perform the method according to any of claims 1 to 16.

19. A controller (102) configured to perform the method according to any of claims 1 to 16 comprising: a processor (118) configured to obtain the angle of inclination of the slope (144), the accelerator input value (132), and the required braking force value: a memory (120) storing calibration parameters for the assistive downhill braking function; an interface for receiving information related to the accelerator input value (132) from an accelerator input (106); and an interface for sending control instructions to a braking system (104) and / or a powertrain (116) to adjust the braking force applied to the vehicle (100) based on the obtained required braking force value,