Vehicle longitudinal deceleration control method, device and system and vehicle

Abstract

The invention relates to the technical field of vehicle control, and discloses a vehicle longitudinal deceleration control method, device and system and a vehicle. Under the working condition that the vehicle is located on a low-adhesion road surface and activates an anti-lock braking system for a long distance, if it is determined that main cylinder brake fluid in a hydraulic drive-by-wire braking system is insufficient, the vehicle longitudinal deceleration control method is started; if yes, the hydraulic brake-by-wire system is controlled to close a wheel side pressure release valve, and a main cylinder is controlled to supplement brake fluid; according to hydraulic braking information required by the hydraulic brake-by-wire system for achieving the expected braking effect under the current working condition, caliper braking information generated when a caliper of the electronic parking braking system is used for braking is generated; the caliper braking information comprises parameters when the electronic parking braking system is used for braking to achieve an expected braking effect; and based on the caliper brake information, brake control is performed through a caliper of the electronic parking brake system until the master cylinder reaches the completion condition of brake fluid supplement. The device has the beneficial effect that the braking efficiency of the liquid supplementing device is improved.

Description

Vehicle longitudinal deceleration control methods, devices, systems and vehicles Technical Field

[0001] This application relates to the field of vehicle control technology, and in particular to a vehicle longitudinal deceleration control method, device, system and vehicle. Background Technology

[0002] As intelligent driving technology advances to Level 3 and above, the requirements for braking system redundancy, reliability, and control precision are constantly increasing.

[0003] Currently, when ABS is activated over a long distance on low-adhesion roads, and the master cylinder brake fluid is insufficient, redundant braking can be achieved through solutions such as iBooster+ESC, IPB+RBU, and EMB to achieve longitudinal deceleration control with certain performance.

[0004] However, these solutions cannot effectively solve the problem of deceleration loss during fluid replenishment, resulting in poor braking efficiency. Summary of the Invention

[0005] This application provides a vehicle longitudinal deceleration control method, device, system, and vehicle, which solves the problem of deceleration loss during fluid replenishment and achieves the technical effect of improving the braking efficiency of the fluid replenishment device.

[0006] To achieve the above objectives, the main technical solution adopted in this application includes: Firstly, this application provides a vehicle longitudinal deceleration control method, applied to a vehicle longitudinal deceleration control system, wherein the hydraulic brake-by-wire system in the vehicle longitudinal deceleration control system integrates an electronic parking brake system; the method includes: when the vehicle is on a low-adhesion road surface and the anti-lock braking system is activated over a long distance, if it is determined that the master cylinder brake fluid in the hydraulic brake-by-wire system is insufficient, controlling the hydraulic brake-by-wire system to close the wheel-side pressure relief valve and controlling the master cylinder to replenish the brake fluid; generating caliper braking information when using the caliper of the electronic parking brake system for braking based on the hydraulic braking information required for the hydraulic brake-by-wire system to achieve the expected braking effect under preset conditions; the caliper braking information includes parameters for achieving the expected braking effect when using the electronic parking brake system for braking; and, based on the caliper braking information, controlling braking through the caliper of the electronic parking brake system until the master cylinder meets the condition for replenishing the brake fluid.

[0007] In this embodiment, when the master cylinder brake fluid is insufficient under preset operating conditions, the electronic parking brake system caliper braking is used to compensate for the inability of the hydraulic brake-by-wire system to brake, thereby maintaining the expected braking effect during fluid replenishment and ensuring vehicle braking safety.

[0008] Secondly, this application provides a vehicle longitudinal deceleration control device applied to a vehicle longitudinal deceleration control system. The hydraulic brake-by-wire system within the vehicle longitudinal deceleration control system integrates an electronic parking brake system. The device includes: a fluid replenishment module, which, when the vehicle is on a low-traction road surface and the anti-lock braking system is activated for a long distance, if it is determined that the master cylinder brake fluid in the hydraulic brake-by-wire system is insufficient, controls the hydraulic brake-by-wire system to close the wheel-side pressure relief valves and controls the master cylinder to replenish the brake fluid; and an auxiliary braking module, used to generate caliper braking information when using the electronic parking brake system's calipers for braking, based on the hydraulic braking information required for the hydraulic brake-by-wire system to achieve the expected braking effect under preset conditions. The caliper braking information includes parameters for achieving the expected braking effect when using the electronic parking brake system. Based on the caliper braking information, braking control is performed through the calipers of the electronic parking brake system until the master cylinder meets the conditions for replenishing the brake fluid.

[0009] Thirdly, this application provides a vehicle longitudinal deceleration control system, including: a vehicle stability control system, a hydraulic brake-by-wire system, and an electronic parking brake system; the electronic parking brake system is integrated within the hydraulic brake-by-wire system; and the vehicle stability control system stores a backup of the electronic parking brake system; the vehicle stability control system, the hydraulic brake-by-wire system, and the electronic parking brake system can execute the method described in any one of the above embodiments.

[0010] Fourthly, this application provides a vehicle in which the vehicle longitudinal deceleration control system described in the above embodiments is operated. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0012] Figure 1 is a structural diagram of a vehicle longitudinal deceleration control system provided in an embodiment of this application; Figure 2 is a flowchart of a vehicle longitudinal deceleration control method provided in an embodiment of this application; Figure 3 is a structural diagram of a brake booster provided in an embodiment of this application; Figure 4 is a block diagram of a vehicle longitudinal deceleration control device provided in an embodiment of this application; Figure 5 is a structural schematic diagram of a computer device provided in an embodiment of this application.

[0013] The reference numerals in the accompanying drawings are as follows: 300-Brake booster; 310-Controller; 311-Controller housing; 312-Printed circuit board; 320-Drive assembly; 321-Bearing; 322-Rotor; 323-Stator; 324-Worm gear; 325-Motor housing; 326-Shaft sleeve; 327-Motor; 330-Brake cylinder; 331-Piston; 332-Oil reservoir; 333-Master cylinder housing; 340-Bolt. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0015] As automotive intelligent driving technology advances towards Level 3 (conditional automated driving) and above, higher demands are placed on the redundancy, reliability, and control precision of braking systems. Currently, there are three main technical solutions for achieving Level 3 longitudinal deceleration control: One is braking control based on the iBooster electric braking assist system and the Electronic Stability Control (ESC) system. The iBooster and ESC systems are two independent controllers that communicate via a CAN bus. The advantages of using the iBooster and ESC systems for braking control are excellent performance and complete hydraulic braking redundancy. However, the disadvantages are also significant: excessive mutual backup between the iBooster and ESC systems can easily lead to increased costs.

[0016] The second approach uses an Integrated Power Brake (IPB) system and a Redundancy Brake Unit (RBU) for braking control. This approach, similar to the combination of the iBooster electric braking assist system and the ESC vehicle stability control system, also suffers from excessive redundancy and is relatively expensive.

[0017] The third is the Electronic Mechanical Brake (EMB) system. However, the cost of the EMB system is even higher than the previous two, and there are currently no mass production cases, making the risks uncontrollable.

[0018] Currently, Level 3 autonomous driving requires the braking system to retain redundant braking capability even in the event of a single component failure. The first and second solutions mentioned above are both Two-Box solutions that meet this requirement. Existing Two-Box solutions, such as iBooster+ESC and IPB+RUB, primarily rely on the iBooster or IPB to generate hydraulic pressure for main longitudinal control. In the event of iBooster or IPB failure, ESC or RBU takes over to maintain some performance. This strategy meets regulatory requirements.

[0019] However, both solutions suffer from redundancy and reliability but also high cost. The setup of these two independent control modules presents several issues, including overlapping valve functions, system complexity, communication delays affecting smoothness, the need for the IPB or iBooster to connect to the traditional brake pedal, inflexible layout space, and operating noise that can easily be transmitted to the cab, impacting NVH performance.

[0020] Furthermore, emerging EMB solutions not only lack cost advantages but also lack mass production validation in terms of reliability. In conclusion, there is an urgent need in this field for a new solution that can meet the functional safety requirements of Level 3 assisted driving while significantly reducing costs and improving control performance.

[0021] In vehicles, the Electronic Park Brake (EPB) system is typically used as a standalone unit, only when the vehicle is parked or as an emergency backup. In conventional longitudinal deceleration control, the potential of the EPB is not fully utilized. Furthermore, in conditions requiring extremely low and smooth deceleration, such as in congested traffic, the dynamic control potential of the EPB remains untapped due to the inherent control difficulties of traditional hydraulic brakes.

[0022] Based on this, this application proposes a low-cost, high-performance longitudinal deceleration control method for L3-level advanced driver assistance systems by deeply integrating a hydraulic brake-by-wire (BWA) system, an electronic parking brake (EPB) system, and an electronic stability control (ESC) system. Furthermore, this application fully leverages the advantage of EPB's rapid interaction within the controller. Through the strategy of fusing BWA and ESC with EPB, this application achieves L3-level longitudinal deceleration control. Moreover, during fluid replenishment, the combination of BWA, ESC, and EPB compensates for deceleration loss during this process.

[0023] Compared with IPB+RBU, this application eliminates the complex structures and components such as simulators and solenoid valves in the existing structure. At the same time, it uses the industrially mature ESC module and incorporates EPB into the longitudinal deceleration under normal operating conditions, which can improve the deceleration response rate and increase the endurance.

[0024] Compared to iBooster+ESC, this system uses the same ESC module. BWA eliminates the simulator structure, simplifies the number of oil circuit switching valves, and involves EPB in longitudinal deceleration under normal operating conditions, which can improve deceleration response rate and increase endurance.

[0025] Compared to EMB's one main controller and four controller / wheel-end motors, this application only requires two controllers, BWA and ESC, resulting in lower cost and easier mass production.

[0026] According to an embodiment of this application, a vehicle longitudinal deceleration control method is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be implemented in a vehicle longitudinal deceleration control system. This vehicle longitudinal deceleration control system can be executed by a set of computer-executable instructions. Furthermore, although a logical sequence is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than that shown here.

[0027] The vehicle longitudinal deceleration control system can consist of a vehicle stability control system, a hydraulic brake-by-wire system, and an electronic parking brake system. This longitudinal deceleration control system can operate on one or more controllers within the vehicle. Optionally, the vehicle stability control system, hydraulic brake-by-wire system, and electronic parking brake system can be integrated into a single controller. Alternatively, the vehicle stability control system, hydraulic brake-by-wire system, and electronic parking brake system can be located in multiple controllers.

[0028] Figure 1 is a structural diagram of a vehicle longitudinal deceleration control system provided in an embodiment of this application. As shown in Figure 1, the vehicle longitudinal deceleration control system mainly includes a hydraulic brake-by-wire actuator (BWA) system and an electronic stability control (ESC) system. These two systems can operate on two separate controllers. The BWA can also integrate an electronic parking brake (EPB), and the ESC can also provide backup for the EPB.

[0029] The vehicle's Advanced Driver Assistance System (ADAS) can control both the BWA and ESC controllers after the intelligent driving system is activated.

[0030] The BWA controller can typically control the left front wheel (FL) and right front wheel (FR) directly. Additionally, when integrated with the EPB, the BWA can control the left rear wheel (RR) and right rear wheel (RL) via the EPB. The BWA can also communicate with the Vehicle Control Unit (VCU).

[0031] The ESC can store EPB backup information. The ESC can directly control the left front wheel (FL) and right front wheel (FR). Furthermore, the ESC can also control the left rear wheel (RR) and right rear wheel (RL) based on the EPB backup. The ESC can also communicate with the VCU.

[0032] Figure 2 is a flowchart of a vehicle longitudinal deceleration control method provided in an embodiment of this application. Based on the embodiment shown in Figure 1, as shown in Figure 2, it is applied to a vehicle longitudinal deceleration control system. The hydraulic brake-by-wire system in the vehicle longitudinal deceleration control system integrates an electronic parking brake system. Taking the vehicle as the execution subject, the process includes the following steps: S101, when the vehicle is on a low-adhesion road surface and the anti-lock braking system is activated for a long distance, if it is determined that the master cylinder brake fluid in the hydraulic brake-by-wire system is insufficient, the hydraulic brake-by-wire system is controlled to close the wheel-side pressure relief valve and the master cylinder is controlled to replenish brake fluid.

[0033] For example, when a vehicle is traveling on a low-traction surface and the anti-lock braking system (ABS) is activated for an extended period, the vehicle's controller continuously monitors the brake fluid level in the master cylinder of the hydraulic brake-by-wire system. When it is determined that the brake fluid in the master cylinder is insufficient, the vehicle controls the hydraulic brake-by-wire system to replenish the fluid.

[0034] In one implementation, the fluid replenishment process can involve closing all wheel-side pressure relief valves in the vehicle's control hydraulic drive-by-wire braking system. Subsequently, the vehicle will activate the master cylinder's fluid replenishment mechanism, drawing brake fluid from the reservoir and adding it to the master cylinder until a sufficient amount of brake fluid is reached.

[0035] Optionally, closing all wheel-side pressure relief valves is to prevent brake fluid from leaking from the wheel-sides during the replenishment process, ensuring that brake fluid can be effectively replenished into the master cylinder.

[0036] In one implementation, the hydraulic brake-by-wire system is a system in the vehicle that controls the hydraulic braking force through electronic signals, and has the characteristics of fast response and precise control.

[0037] In one implementation, the master cylinder is the core component of the hydraulic braking system, responsible for generating and transmitting braking hydraulic pressure.

[0038] In one implementation, the wheel-side pressure relief valve is a valve located near the wheel brake, used to release brake fluid when needed to prevent wheel lock-up.

[0039] In one implementation, the vehicle can monitor the brake fluid level using a level sensor installed in the master cylinder.

[0040] In one implementation, the vehicle can use multiple judgment strategies to determine if the master cylinder brake fluid is insufficient. For example, when the fluid level is lower than a set threshold, it is determined that the master cylinder brake fluid is insufficient.

[0041] Optionally, this threshold value can be a fixed value set by technicians based on experimental data or experience. For example, when the maximum brake fluid capacity in the master cylinder is 50, the threshold value can be set to 5.

[0042] Optionally, the threshold value can also be a value calculated based on the maximum capacity of the brake fluid in the master cylinder, according to a preset percentage. For example, when the preset percentage is 10% and the maximum capacity of the brake fluid in the master cylinder is 50, the threshold value can be 5.

[0043] In one implementation, closing the wheel-side pressure relief valve can be achieved by sending a signal to the corresponding solenoid valve via an electronic control unit (ECU).

[0044] In one implementation, master cylinder replenishment can be accomplished by an electric pump or a motor-driven pump integrated into a hydraulic brake-by-wire system.

[0045] In one example, when a vehicle activates its anti-lock braking system over a long distance on a low-traction surface, the vehicle will need to perform multiple intermittent braking maneuvers via the hydraulic brake-by-wire system to gradually reduce its speed, thereby ensuring a smooth reduction in speed and keeping it within a safe range to prevent skidding.

[0046] Optionally, because the master cylinder of the hydraulic brake-by-wire system needs to be used frequently and for extended periods during this process, there is a significant demand for brake fluid. If insufficient brake fluid occurs during this process, the hydraulic brake-by-wire system may require fluid replenishment, leading to brake interruption and potentially posing a safety risk.

[0047] S102. Based on the hydraulic braking information required for the hydraulic brake-by-wire system to achieve the expected braking effect under the current operating conditions, generate caliper braking information when using the electronic parking brake system. The caliper braking information includes parameters for achieving the expected braking effect when using the electronic parking brake system.

[0048] For example, once it is determined that the master cylinder brake fluid is insufficient and replenishment begins, the hydraulic brake-by-wire system will be unable to provide braking. In order to ensure normal braking of the vehicle, this application proposes integrating an electronic parking brake system into the hydraulic brake-by-wire system, thereby utilizing the electronic parking brake system to achieve braking during the replenishment process.

[0049] First, the vehicle can determine the expected braking effect under the current operating conditions. Furthermore, the vehicle can calculate the hydraulic braking information required for the hydraulic brake-by-wire system to achieve the expected braking effect when the anti-lock braking system is activated over a long distance on a low-traction road surface.

[0050] Furthermore, based on this hydraulic braking information, the vehicle can analyze and determine the caliper braking information required to achieve the desired braking effect under the current operating conditions when using the electronic parking brake system. The electronic parking brake system uses calipers for braking.

[0051] In one implementation, hydraulic braking information refers to parameters such as hydraulic braking force and braking time required by the hydraulic brake-by-wire system to achieve the expected braking effect under the current operating conditions.

[0052] In one implementation, the electronic parking brake system is a system that controls the parking brake via electronic signals. It is typically used for parking when the vehicle is stationary, but can also be used as an auxiliary brake under certain conditions. The electronic parking brake system usually achieves braking by clamping the wheels with calipers.

[0053] In one implementation, caliper braking information refers to the control parameters required when using EPB calipers for braking, such as clamping force, clamping time, and release timing. These parameters are designed to ensure that during fluid replenishment, braking by the EPB calipers can compensate for the reduced braking performance caused by insufficient brake fluid in the master cylinder.

[0054] In one implementation, the vehicle can use the ECU to calculate the required caliper braking information based on the hydraulic braking information and the characteristics of the EPB system.

[0055] In one implementation, the caliper braking information may include multiple parameters, which can be dynamically adjusted according to actual working conditions and braking requirements.

[0056] In one implementation, the vehicle can send caliper braking information to the control unit of the EPB system via CAN bus or other communication methods to achieve precise braking control.

[0057] S103. Based on caliper braking information, brake control is performed through the calipers of the electronic parking brake system until the master cylinder reaches the condition for brake fluid replenishment.

[0058] For example, during fluid replenishment, the vehicle uses the electronic parking brake system to control the calipers based on generated caliper braking information. The EPB calipers clamp and release according to predetermined parameters based on the received braking information to simulate the braking effect of a hydraulic brake-by-wire system without fluid replenishment.

[0059] In one implementation, brake control based on caliper braking information refers to the process of precisely controlling the EPB caliper according to pre-generated caliper braking information.

[0060] In one implementation, the condition for completing brake fluid replenishment is that the amount of brake fluid in the master cylinder reaches a safe or design-required level.

[0061] In one implementation, once the master cylinder reaches the condition for brake fluid replenishment, the vehicle will stop using the EPB caliper for braking control and resume normal hydraulic braking system operation.

[0062] In one implementation, the vehicle can receive caliper braking information through the control unit of the EPB system and control the clamping and releasing of the calipers based on this information.

[0063] In one implementation, during the replenishment process, the vehicle can continuously monitor the brake fluid level in the master cylinder, and when the replenishment conditions are met, immediately stop using the EPB caliper for braking control.

[0064] In one implementation, the vehicle can also dynamically adjust the caliper braking information according to actual working conditions and braking requirements to achieve optimal braking performance.

[0065] In this embodiment, when the master cylinder brake fluid is insufficient due to long-distance activation of the anti-lock braking system on low-adhesion road surfaces, the electronic parking brake system caliper braking is used to compensate for the inability of the hydraulic brake-by-wire system to brake, thereby maintaining the expected braking effect during fluid replenishment and ensuring vehicle braking safety.

[0066] In one example, in step S102 above, caliper braking information is generated when the caliper of the electronic parking brake system brakes when braking, based on the hydraulic braking information required for the hydraulic brake-by-wire system to achieve the expected braking effect under the current operating conditions. This includes: S1021, determining the deceleration for each braking action and the execution time for each braking action based on the hydraulic braking information.

[0067] For example, in an ABS braking scenario, the hydraulic braking information may include braking information from multiple intermittent braking actions. Therefore, the vehicle can analyze this hydraulic braking information to obtain the deceleration of each braking action and the time interval between multiple braking actions. Based on this time interval, using the current moment as the initial moment, the computer device can calculate the execution time of each braking action during the expected braking process.

[0068] S1022. Calculate the target braking current for each clamping action of the caliper based on the deceleration of each braking action.

[0069] For example, in an electronic parking brake system, a vehicle can brake its wheels by clamping the brake discs of the wheels with calipers. Based on this deceleration, the vehicle can determine the clamping force required to achieve that deceleration, as well as the target braking current required to achieve that clamping force, according to a preset mapping off table.

[0070] In one implementation, the target braking current is the current corresponding to the moment of maximum deceleration. At this time, the clamping force of the electronic parking brake system is at its maximum, and the braking current reaches its maximum value for that braking action.

[0071] S1023. Generate caliper braking information based on the execution time of each braking action and the target braking current for each braking action.

[0072] For example, the braking execution time can specifically be the time when braking begins. The vehicle can determine the braking current corresponding to the midpoint between two braking execution times as the target braking current. Furthermore, the vehicle determines the minimum braking current corresponding to the execution time between the two target braking currents based on a safe rate of change.

[0073] In one implementation, the minimum braking current can be the moment when the clamping force of the caliper is at its minimum during the process of the caliper of the electronic parking brake system gradually loosening and then gradually clamping again between two target braking currents.

[0074] In one implementation, the minimum braking current can typically be 0.

[0075] In one implementation, when the target braking current is very high, the current may not be able to reach zero during the reduction process due to the safety rate of change limit of the current. In this case, the vehicle can use the minimum achievable braking current as the minimum braking current.

[0076] In this example, by determining the execution time, target braking current, and minimum braking current in the caliper braking information, the change curve of the braking current in the caliper braking information is plotted. This improves the electronic parking brake system's ability to control the clamping force of the caliper based on the change curve of the braking current, thereby simulating the hydraulic brake-by-wire system to achieve the expected braking requirements.

[0077] In another example, the vehicle can also dynamically determine whether the brake fluid in the current master cylinder is sufficient based on the current braking demand. In step S101 above, the process of dynamically determining whether there is insufficient brake fluid may include: S1011, determining the number of braking operations when the hydraulic brake-by-wire system performs intermittent braking based on the current operating conditions.

[0078] For example, during vehicle operation, the hydraulic brake-by-wire system determines the specific number of braking operations required when intermittent braking is needed, based on the current operating conditions.

[0079] In one implementation, the specific number of braking cycles can be determined based on information such as the road surface adhesion coefficient, vehicle speed range, and driver operating habits.

[0080] In one implementation, the current operating condition refers to a series of pre-set condition parameters based on the environment, road conditions, and driving needs before or during vehicle operation.

[0081] In one implementation, intermittent braking is a braking method. During intermittent braking, the vehicle can be braked quickly and repeatedly to smoothly decelerate and avoid the risk of loss of control caused by emergency braking.

[0082] In one implementation, the vehicle can use built-in sensors and algorithms to monitor parameters such as road surface adhesion coefficient and vehicle speed in real time, and calculate the optimal number of braking points based on preset operating conditions.

[0083] In one implementation, the vehicle can also predict and optimize the number of braking points under different operating conditions based on historical data and machine learning models, so as to improve the stability and reliability of braking performance.

[0084] S1012. Determine the brake fluid consumption based on the basic amount of brake fluid required for basic braking and the number of braking cycles based on the hydraulic brake-by-wire system.

[0085] For example, the vehicle can obtain the base amount of brake fluid required for the hydraulic brake-by-wire system to perform basic braking. After determining the number of braking operations performed by the hydraulic brake-by-wire system during intermittent braking, the vehicle can calculate the brake fluid consumption during the entire braking process based on the base amount of brake fluid required for each basic braking operation.

[0086] In one implementation, basic braking refers to a routine braking operation performed by the vehicle's hydraulic brake-by-wire system.

[0087] In one implementation, the brake fluid baseline quantity refers to the amount of brake fluid required to achieve one basic braking action. Optionally, this brake fluid baseline quantity can be based on laboratory measurement data. Alternatively, the brake fluid baseline quantity can be calculated based on the vehicle's historical information.

[0088] In one implementation, brake fluid consumption refers to the total amount of brake fluid that the hydraulic brake-by-wire system needs to consume during the currently planned braking process.

[0089] In one implementation, the vehicle can calculate the total brake fluid consumption by multiplying the base amount of brake fluid required for each basic braking action by the product of the number of braking actions.

[0090] In one implementation, the vehicle can also generate a calculated compensation amount based on historical information about brake fluid consumption during braking by the hydraulic brake-by-wire system. The vehicle can then optimize the brake fluid consumption based on this compensation amount. For example, the vehicle can calculate the sum of the brake fluid consumption and the compensation amount to obtain the optimized brake fluid consumption.

[0091] In another implementation, the vehicle can also have a preset float coefficient. The vehicle can calculate the optimized brake fluid consumption by multiplying the brake fluid consumption by this float coefficient. Optionally, this float coefficient can further ensure that sufficient brake fluid is maintained in the hydraulic brake-by-wire system.

[0092] S1013. If the remaining brake fluid in the master cylinder is less than the brake fluid consumption, then the brake fluid in the master cylinder of the hydraulic brake-by-wire system is insufficient.

[0093] For example, after calculating the brake fluid consumption, the vehicle compares the consumed brake fluid with the current remaining brake fluid in the master cylinder. If the remaining brake fluid in the master cylinder is less than the consumed brake fluid, it indicates that the brake fluid in the master cylinder of the vehicle's hydraulic brake-by-wire system is insufficient, and appropriate fluid replenishment measures need to be taken to ensure the normal operation of the braking system and driving safety.

[0094] In one implementation, the remaining brake fluid level refers to the amount of brake fluid currently remaining in the master cylinder.

[0095] In one implementation, insufficient brake fluid means that the remaining amount of brake fluid in the master cylinder is insufficient to support the hydraulic brake-by-wire system in completing the current braking task.

[0096] In this example, the number of intermittent braking operations is determined based on the current operating conditions, and the brake fluid consumption is calculated in conjunction with the basic amount of brake fluid required for basic braking. Then, the brake fluid consumption is compared with the remaining brake fluid in the master cylinder to determine whether the brake fluid is sufficient. This method achieves the effect of dynamically and accurately assessing whether the brake fluid level in the master cylinder of the hydraulic brake-by-wire system is sufficient based on the braking demand under the current operating conditions.

[0097] In one example, the caliper braking information includes braking current. In step S103 above, braking control is performed on the caliper of the electronic parking brake system based on the caliper braking information, including: S1031, adjusting the clamping force of the caliper based on the braking current so that the caliper brakes through alternating clamping and releasing.

[0098] For example, during the braking operation performed by the calipers of the electronic parking brake system, the clamping force of the calipers of the electronic parking brake system is adjusted based on the braking current in the caliper braking information.

[0099] In one implementation, the caliper braking information may include a series of timing-sequential braking currents. Based on this series of braking currents, the vehicle can precisely control the clamping force of the caliper, thereby causing the caliper to perform an alternating clamping and releasing process. This alternating clamping and releasing process replaces the intermittent braking process of a hydraulic brake-by-wire system.

[0100] In one implementation, the braking current refers to the current value that drives the caliper of the electronic parking brake system to clamp. The magnitude of this braking current directly reflects the magnitude of the braking force applied by the caliper.

[0101] In one implementation, the caliper is the core actuator of the electronic parking brake system. The electronic parking brake system can achieve the vehicle's parking brake or auxiliary braking function by clamping or releasing the brake disc.

[0102] In one implementation, the clamping force is the pressure applied by the caliper to the brake disc. The greater the clamping force, the stronger the braking effect.

[0103] In this example, by dynamically adjusting the caliper clamping force based on the braking current, the caliper alternately clamps and releases, achieving the braking effect of a hydraulic brake-by-wire system performing intermittent braking. This achieves the braking effect during fluid replenishment and improves vehicle safety.

[0104] In one example, in step S103 above, after the vehicle controls the wheels with calipers, the vehicle can further improve its safety by calculating the vehicle's slip ratio and optimizing braking based on that slip ratio. This process may include: S1032, monitoring the speed of each wheel and calculating the slip ratio based on that speed.

[0105] For example, during the braking process of the electronic parking brake system, the vehicle continuously monitors the wheel speed of each wheel. Based on the acquired wheel speed and other information such as the vehicle's own speed, the vehicle calculates the slip ratio of that wheel according to a specific slip ratio calculation formula.

[0106] In one implementation, single-wheel speed refers to the linear velocity corresponding to the number of revolutions a single wheel makes per unit time. Single-wheel speed reflects how fast the wheel rotates and is one of the important parameters of the vehicle's driving status.

[0107] In one implementation, the slip ratio describes the degree of relative sliding between the tire and the ground during braking or driving. The magnitude of the slip ratio indicates whether the tire is in a state of pure rolling, rolling and sliding at the same time, or pure sliding.

[0108] In one implementation, the vehicle can collect the wheel speed of a single wheel in real time using wheel speed sensors installed on the wheels.

[0109] S1033. If the slip ratio reaches the threshold value, release the caliper of the electronic parking brake system.

[0110] For example, after calculating the slip ratio, the vehicle compares the calculated slip ratio with a preset threshold. When the slip ratio of a wheel reaches this threshold, it means that the vehicle may be at risk of skidding. At this time, the vehicle will immediately send a command to the electronic parking brake system to release the calipers of the electronic parking brake system on the corresponding wheel, thereby preventing the wheel from losing traction due to excessive slippage, which could lead to loss of vehicle control and ensure the braking stability and driving safety of the vehicle.

[0111] In one implementation, the threshold value is a pre-set specific value used as a critical criterion to determine whether the slip ratio has reached a level requiring intervention. When the slip ratio reaches or exceeds this value, the vehicle triggers corresponding control actions. Optionally, this threshold value can be a laboratory measurement.

[0112] In one implementation, releasing the caliper of the electronic parking brake system means adjusting the braking current to change the clamping force of the caliper, thereby causing the caliper of the electronic parking brake system to loosen its clamping on the brake disc and stop applying braking force to the wheel.

[0113] In this example, by monitoring the wheel speed of a single wheel in real time and calculating the slip ratio, the electronic parking brake system caliper is released when the slip ratio reaches a threshold value, thereby preventing excessive wheel slip and ensuring braking stability.

[0114] In one example, the vehicle's longitudinal deceleration control system may include a vehicle stability control system, a hydraulic brake-by-wire system, and an electronic parking brake system. When the hydraulic brake-by-wire system is functioning correctly, the vehicle can brake using both the hydraulic brake-by-wire system and the electronic parking brake system. Conversely, when the hydraulic brake-by-wire system malfunctions, the vehicle can brake using both the vehicle stability control system and the electronic parking brake system. This configuration provides redundancy for the vehicle, ensuring its safety.

[0115] In both of the above scenarios, the vehicle stability control system and the hydraulic brake-by-wire system may require brake fluid replenishment during operation. Therefore, the vehicle can be pre-set with different conditions for brake fluid replenishment for these two systems. Specifically, one condition is that if the hydraulic brake-by-wire system is available, the brake fluid replenishment is completed when the brake fluid level in the master cylinder rises to a first threshold.

[0116] For example, when the hydraulic brake-by-wire system is available, the vehicle first invokes the hydraulic brake-by-wire system to brake when braking is required. If the master cylinder of the hydraulic brake-by-wire system needs to be replenished with brake fluid, the vehicle will determine whether the brake fluid has been replenished based on the completion conditions of the brake fluid replenishment in the hydraulic brake-by-wire system.

[0117] Specifically, the vehicle can determine whether brake fluid replenishment is complete by judging whether the brake fluid level in the master cylinder has risen to a preset first threshold. Once the brake fluid level in the master cylinder reaches this threshold, the vehicle considers brake fluid replenishment complete and will stop the replenishment operation. Furthermore, the vehicle can restart the hydraulic brake-by-wire system to brake after the brake fluid replenishment is complete.

[0118] In one implementation, the first threshold is a pre-set brake fluid level value based on the characteristics and normal operating requirements of the hydraulic brake-by-wire system. When the brake fluid level in the master cylinder reaches this value, it indicates that the brake fluid has been replenished to an appropriate level to meet the normal operating requirements of the hydraulic brake-by-wire system.

[0119] For example, the first threshold can be a fixed value set by technicians based on experimental data or experience. For example, when the maximum capacity of brake fluid in the master cylinder is 50, the first threshold can be set to 45.

[0120] For example, the threshold setting can also be a value calculated based on the maximum capacity of the brake fluid in the master cylinder, according to a preset percentage. For instance, when the preset percentage is 90% and the maximum capacity of the brake fluid in the master cylinder is 50, the threshold setting can be 45.

[0121] Another scenario: If the electronic stability system is available, the brake fluid replenishment is completed when the electronic stability system accumulator is drained.

[0122] For example, when the hydraulic brake-by-wire system is unavailable, the vehicle will determine whether the electronic stability control system (ESC) is available when braking is required. If the ESC is available, the vehicle will activate it for braking. During braking using the ESC, the vehicle needs to utilize the wheel cylinders for braking. If the brake fluid level in the wheel cylinders is insufficient, the ESC will also need to replenish the brake fluid in the wheel cylinders.

[0123] During the brake fluid replenishment process of the wheel cylinders by the electronic stability control system, the vehicle can monitor the accumulator's fluid discharge status through the hydraulic control unit. The vehicle can confirm that brake fluid replenishment is complete only after verifying that the brake fluid stored in the accumulator has been completely released into the wheel cylinders or returned to the reservoir. This judgment condition ensures the dynamic balance of hydraulic energy in the braking system, preventing insufficient or excessive brake fluid replenishment due to residual pressure in the accumulator, thereby guaranteeing the normal functioning of the electronic stability control system.

[0124] In one implementation, the electronic stability control system is an active safety system that monitors the vehicle's driving status (such as yaw rate and wheel speed) and automatically adjusts the braking force of one or more wheels to correct understeer or oversteer and maintain vehicle stability. This electronic stability control system is a redundant braking control system installed in the vehicle.

[0125] In one implementation, the accumulator is a high-pressure energy storage device in the vehicle's electronic stability system. It typically consists of a piston and a sealed cavity, used to store brake fluid and release hydraulic energy when the system needs rapid pressurization, thereby improving braking response speed.

[0126] In one implementation, complete drainage means that the brake fluid stored inside the accumulator is completely released into the wheel cylinder or returned to the reservoir through the hydraulic lines, and the system pressure drops to a safe range.

[0127] In one implementation, the vehicle monitors hydraulic pressure changes in real time during the draining process using a pressure sensor installed on the accumulator outlet pipeline. Draining is considered complete when the sensor detects that the pressure remains consistently below a preset threshold. Optionally, this preset threshold can be determined based on atmospheric pressure. For example, the preset threshold can be the value of atmospheric pressure. That is, the system determines that draining is complete when the sensor detects that the pressure remains consistently below atmospheric pressure.

[0128] Alternatively, a flow meter can be installed in the accumulator drain line to measure the volume of brake fluid drained per unit time and calculate the total drain volume. Drainage is considered complete when the cumulative drain volume reaches the accumulator's design capacity. Optionally, this design capacity can be an empirical value. For example, the design capacity could be 10 ml. For instance, drainage is considered complete when the cumulative drain volume reaches 10 ml.

[0129] Alternatively, the vehicle can determine whether drainage is complete by combining both drainage time and pressure changes. For example, the system might set the drainage duration to 2 seconds, while simultaneously requiring the pressure to remain below a preset threshold for the last 0.5 seconds. If both conditions are met, drainage is considered complete; if the time requirement is met but the pressure requirement is not, the drainage time is extended until the conditions are met.

[0130] Alternatively, the vehicle monitors the effect of fluid draining on brake pressure using wheel cylinder pressure sensors. When the accumulator drains and causes the wheel cylinder pressure to reach the target value (such as 50 bar required to correct sideslip) and no longer rises, the system infers that the accumulator has been emptied, thus determining that the draining is complete.

[0131] In this example, by setting different completion conditions for brake fluid replenishment scenarios in the hydraulic brake-by-wire system and the electronic stability control system, the accurate judgment of brake fluid replenishment completion is achieved, thereby improving vehicle safety and braking effectiveness.

[0132] In one example, in Level 3 autonomous driving technology, to ensure the redundancy and reliability of the braking system, the vehicle can use the hydraulic brake-by-wire system for braking, and then activate the electronic stability control system when the hydraulic brake-by-wire system is detected as unavailable. Furthermore, if the electronic stability control system is also detected as unavailable, the vehicle can use the calipers of the electronic parking brake system to control braking and achieve the desired braking effect.

[0133] For example, when both the vehicle's hydraulic brake-by-wire system and electronic stability control system malfunction or are unable to operate normally under extreme conditions, the vehicle will automatically switch to emergency braking mode. The vehicle can apply braking force to the wheels through the calipers of the electronic parking brake system to achieve basic braking function, thereby ensuring the vehicle's braking needs and improving vehicle safety.

[0134] In one implementation, this process is divided into three key stages: First, the vehicle detects a failure in the hydraulic brake-by-wire system and the electronic stability control system via sensors, triggering the emergency intervention logic of the electronic parking brake system. Second, the electronic parking brake system's control unit (ECU) calculates the required braking force based on parameters such as vehicle speed and wheel speed, and drives the caliper motor to clamp the brake disc. Finally, the system continuously monitors the braking effect, dynamically adjusting the caliper clamping force or applying braking in stages to ensure the vehicle decelerates to a stop within a safe distance. This entire process is based on a mechanical-hydraulic redundancy design, achieving precise control of emergency braking through the electronic control system.

[0135] In this example, when the hydraulic brake-by-wire system and the vehicle's electronic stability system fail, the electronic parking brake system calipers are used to implement dynamic electronic braking, thereby achieving basic braking function in emergency conditions and achieving an effect close to the expected braking distance and vehicle stability.

[0136] Based on the above embodiments, a specific execution strategy for long-distance activation of the Anti-lock Braking System (ABS) on low-friction surfaces can be as follows: When a vehicle activates ABS over a long distance on a low-friction surface, there may be insufficient brake fluid in the master cylinder. In this case, the Brake Flow Actuation (BWA) and Electronic Stability Control (ESC) can close the wheel-side pressure relief valves to replenish the master cylinder fluid. Furthermore, during this process, the BWA and ESC control the EPB calipers to participate, thereby increasing wheel control effectiveness during fluid replenishment. The BWA and ESC in the vehicle can calculate the consumed brake fluid based on the basic braking fluid requirement plus the number of braking cycles. When the master cylinder brake fluid is about to run out, the EPB calipers are clamped using current control and judgment. The BWA and ESC can also monitor the clamping status. The vehicle can release the EPB only when the rear wheels are clamped by the EPB and approach a locked state, and the wheel speed of a single wheel reaches the slip ratio threshold. The vehicle can continue this process until the BWA master cylinder motor reverses to complete fluid replenishment and the ESC accumulator is drained.

[0137] In addition to this operating condition, the vehicle, based on the longitudinal deceleration control system shown in Figure 1, can also achieve the following four operating conditions: Condition 1: Deceleration input by ADAS, and the VCU can perform deceleration. Condition 2: Deceleration input by ADAS, but the VCU cannot perform deceleration. Condition 3: During normal driving, ADAS does not request deceleration. Condition 4: During normal driving, ADAS requests deceleration.

[0138] For the four operating conditions mentioned above, the specific execution strategy of the vehicle can include: For operating condition 1, after the ADAS inputs deceleration, it can first call the VCU to perform deceleration control. When the deceleration input by the ADAS is greater than the maximum deceleration that the VCU can achieve, the vehicle can control the VCU to execute the maximum deceleration. Furthermore, the vehicle can also compensate for the remaining acceleration through BWA. If BWA fails, it will compensate through ESC.

[0139] For example, when the maximum acceleration of the VCU is The deceleration input to ADAS is At this time, the vehicle can send control commands to the VCU, and the VCU will drive the motor to achieve maximum speed. The vehicle can compensate for the remaining deceleration through BWA boost. The deceleration. When BWA fails, the vehicle can compensate for the remaining deceleration through ESC boost. The deceleration.

[0140] For condition 2, if the VCU cannot achieve deceleration after the ADAS inputs a deceleration value, the vehicle can directly increase pressure by controlling the BWA to achieve vehicle deceleration. If the BWA malfunctions, vehicle deceleration will be achieved through ESC.

[0141] For condition 3, during normal driving, when ADAS does not request deceleration, the vehicle can also achieve zero rear wheel drag by controlling the EPB caliper to reverse via BWA. This zero drag indicates that the friction pads are completely separated from the brake disc, allowing the wheels to rotate freely without additional resistance.

[0142] Specifically, the EPB caliper reverse rotation can increase the distance between the friction pads and the brake disc, thereby providing sufficient clearance between the friction pads and the brake disc to prevent wheel drag caused by friction, thus achieving a zero drag effect.

[0143] For Condition 4, during normal driving, when ADAS is preparing to request deceleration, the vehicle can pre-boost when BWA receives the ADAS pre-request, thereby improving the deceleration response rate.

[0144] Based on the above embodiments, the computer program can control the above four operating conditions and the operating condition shown in Figure 2 where the vehicle activates the anti-lock braking system over a long distance on a low-friction surface through a main function. The operating condition where the vehicle activates the anti-lock braking system over a long distance on a low-friction surface can be designated as operating condition 5. Furthermore, this main function can implement the operation under the above five operating conditions through global variables and by calling other functions.

[0145] The vehicle can be controlled through the main function. Optionally, this main function can be denoted as `brake_control_main(void)`. The execution process inside this main function may include the following steps: S201, the vehicle can first obtain the current operating mode of the vehicle through the operating condition judgment function.

[0146] In one implementation, the operating condition determination function can be denoted as determine_operating_case().

[0147] In one implementation, the vehicle can have four preset operating modes. These four operating modes can be denoted as BRAKE_MODE_NORMAL, BRAKE_MODE_ADAS_ACTIVE, BRAKE_MODE_ABS_ACTIVE, and BRAKE_MODE_EMERGENCY, respectively.

[0148] Optionally, BRAKE_MODE_NORMAL is used to indicate whether it is normal driving mode. BRAKE_MODE_NORMAL=0 indicates normal driving mode. Otherwise, BRAKE_MODE_NORMAL=1 indicates abnormal driving mode.

[0149] Optionally, BRAKE_MODE_ADAS_ACTIVE is used to indicate whether ADAS is in active mode. ADAS is active when BRAKE_MODE_ADAS_ACTIVE=0. Otherwise, ADAS is not active when BRAKE_MODE_ADAS_ACTIVE=1.

[0150] Optionally, BRAKE_MODE_ABS_ACTIVE indicates whether the Anti-lock Braking System (ABS) is in active mode. ABS is active when BRAKE_MODE_ABS_ACTIVE=0. Otherwise, ABS is not active when BRAKE_MODE_ABS_ACTIVE=1.

[0151] Optionally, BRAKE_MODE_EMERGENCY is used to indicate whether it is in emergency braking mode. When BRAKE_MODE_EMERGENCY=0, it is in emergency braking mode. Otherwise, when BRAKE_MODE_EMERGENCY=1, it is in non-emergency braking mode.

[0152] Optionally, these four operating modes can be used by the vehicle longitudinal deceleration control system to determine the state of the above five operating conditions during the specific implementation process.

[0153] S202. The vehicle can enter the operation corresponding to each working mode based on the working mode returned by the working condition judgment function at the current moment, through the switch-case conditional branch control structure.

[0154] S203. When the operating mode is ADAS activated mode (BRAKE_MODE_ADAS_ACTIVE), the vehicle can call the first execution function of condition 1 when the VCU is available and the maximum deceleration of the VCU is greater than 0.1f. Otherwise, the vehicle can call the second execution function of condition 2 when the VCU is unavailable or the maximum deceleration of the VCU is less than or equal to 0.1f, and the vehicle can call the fourth execution function of condition 4 when requesting prefilling.

[0155] The first execution function can be denoted as handle_case1(). The second execution function can be denoted as handle_case2(). The third execution function can be denoted as handle_case4().

[0156] S204. When the operating mode is ABS activated mode (BRAKE_MODE_ABS_ACTIVE), the vehicle can call the fifth execution function of operating condition 5.

[0157] The fifth execution function can be denoted as handle_case5().

[0158] S206. When the operating mode is normal driving mode (BRAKE_MODE_NORMAL), the vehicle does not call the operating condition function.

[0159] S207. In cases other than a switch, the vehicle may call the third execution function of condition 3.

[0160] The third execution function can be denoted as handle_case3().

[0161] In one implementation, the vehicle can define a data structure for system status parameters. This data structure can be named `system_status_t`. This data structure can be used to store system status parameters for use by the control logic in decision-making.

[0162] Optionally, the data structure may include a parameter indicating the ADAS deceleration request. This ADAS deceleration request parameter may be denoted as `adas_deceleration_request`. The data type of this ADAS deceleration request parameter may be float. The unit of this ADAS deceleration request parameter may be m / s².

[0163] Optionally, the data structure may include a parameter indicating the maximum deceleration of the VCU. This parameter for the maximum deceleration of the VCU may be denoted as vcu_max_deceleration. The data type of this parameter for the maximum deceleration of the VCU may be float.

[0164] Optionally, this data structure may include a parameter indicating whether the VCU is available. This parameter can be denoted as `vcu_available`. The data type of this parameter can be bool.

[0165] Optionally, this data structure may include a parameter indicating whether BWA is available. This parameter, indicating whether BWA is available, can be denoted as `bwa_available`. The data type of this parameter can be bool.

[0166] Optionally, this data structure may include a parameter indicating whether ESC is available. This parameter, indicating whether ESC is available, can be denoted as `esc_available`. The data type of this parameter can be bool.

[0167] Optionally, this data structure may include a parameter indicating whether the ABS is active. This parameter indicating whether the ABS is active can be denoted as `abs_active`. The data type of this parameter can be bool.

[0168] Optionally, the data structure may include a parameter indicating whether the road surface is low-adhesion. This parameter can be denoted as `low_mu_road`. The data type of this parameter can be `bool`. For example, a low-adhesion road surface can be a wet / slippery road surface.

[0169] Optionally, the data structure may include a parameter indicating the master cylinder brake fluid level. This master cylinder brake fluid level parameter can be denoted as `master_cylinder_fluid_level`. The data type of this master cylinder brake fluid level parameter can be float. This master cylinder brake fluid level parameter can be a percentage value.

[0170] Optionally, this data structure may include a parameter indicating vehicle speed. This vehicle speed parameter can be denoted as `vehicle_speed`. The data type of this vehicle speed parameter can be `float`. The unit of this vehicle speed parameter can be `km / h`.

[0171] In one implementation, the vehicle can define a data structure to record the contribution values ​​of each braking subsystem. This data structure can be named `brake_distribution_t`. This data structure can be used to record the contribution values ​​of each braking subsystem for monitoring and debugging.

[0172] Optionally, the data structure may include a parameter indicating the deceleration provided by the mechanical brake (hydraulic brake). This parameter, representing the deceleration provided by the mechanical brake (hydraulic brake), may be denoted as `mechanical_brake`. The data type of this parameter may be `float`.

[0173] Optionally, the data structure may include a parameter indicating the deceleration provided by regenerative braking (recovering energy through a motor). This parameter for deceleration provided by regenerative braking (recovering energy through a motor) may be denoted as `regenerative_brake`. The data type of this parameter for deceleration provided by regenerative braking (recovering energy through a motor) may be float.

[0174] Optionally, the data structure may include a parameter indicating the deceleration provided by the EPB (Electronic Parking Brake). This parameter representing the deceleration provided by the EPB can be denoted as epb_brake. The data type of this parameter can be float.

[0175] In one implementation, the vehicle can define multiple global variables. These global variables can be used to store global state, which can be shared by all functions.

[0176] Optionally, the vehicle can define a global variable of data structure with data type "system state parameter" to describe the current system state. This global variable can be denoted as g_sys_status = {0}.

[0177] Optionally, the vehicle can define a global variable of data type that records the contribution values ​​of each braking subsystem for front brake distribution. This global variable can be denoted as g_brake_dist = {0}.

[0178] Optionally, the vehicle can define a global variable of type bool to indicate whether ADAS requests prefill (preboost). This global variable can be denoted as g_adas_prefill_request = false. Optionally, the value of the false parameter indicates that the default value of this global variable is not to request prefill.

[0179] In one implementation, the vehicle may also provide multiple hardware control interfaces.

[0180] For example, the hardware control interface used to control the VCU to implement regenerative braking (such as energy recovery in electric vehicles) can be denoted as vcu_control_deceleration(float decel). This hardware interface is used to implement VCU regenerative braking control (such as sending commands via the CAN bus).

[0181] For example, the hardware control interface for controlling the pressure of a hydraulic braking system via BWA can be denoted as bwa_control_pressure(float pressure). This hardware interface is used to implement BWA pressure control (such as adjusting the hydraulic braking pressure).

[0182] For example, the hardware control interface of ESC, which is a redundant system and takes over hydraulic control in the event of a BWA failure, can be denoted as esc_control_pressure(float pressure). This hardware interface is used to implement ESC pressure control (such as through valve regulation).

[0183] For example, in situations with low liquid levels or low road adhesion, the hardware control interface for using EPB to assist ABS anti-lock braking can be denoted as epb_control_abs_assist(bool enable, float slip_threshold). This hardware interface is used to control the wheel slip ratio with the assistance of EPB when ABS is activated.

[0184] In one implementation, for the above-mentioned operating condition 1, the vehicle can achieve partial deceleration through the VCU. During this process, the vehicle can prioritize the use of regenerative braking, with the insufficient portion supplemented by hydraulic braking (BWA or ESC).

[0185] Specifically, the execution process of the first execution function handle_case1(void) in condition 1 can include: the vehicle first obtains the ADAS requested deceleration and the VCU maximum deceleration. If the ADAS requested deceleration is greater than or equal to the VCU maximum deceleration, it indicates that the VCU fully meets the requirements. At this time, the vehicle can control the VCU to achieve regenerative braking by calling the vcu_control_deceleration(adas_request) interface. Here, the parameter adas_request is the ADAS requested deceleration. Furthermore, the vehicle can set the deceleration provided by regenerative braking (recovering energy through the motor) to the ADAS requested deceleration. Simultaneously, the deceleration provided by the vehicle's mechanical braking (hydraulic braking) can be set to 0.0f.

[0186] Otherwise, if the ADAS-requested deceleration is less than the VCU's maximum deceleration, it indicates that the maximum capacity provided by the VCU cannot meet the demand. In this case, the vehicle can control the VCU to brake at its maximum capacity by calling the `vcu_control_deceleration(vcu_capable)` interface, where `vcu_capable` is the VCU's maximum deceleration. Simultaneously, the vehicle can calculate the difference between the ADAS-requested deceleration and the VCU's maximum deceleration to obtain the remaining power. Furthermore, the deceleration provided by the vehicle's regenerative braking (recovering energy through the motor) can be set to the VCU's maximum deceleration.

[0187] Furthermore, when the bwa_available parameter indicates that BWA is available, the vehicle can implement BWA pressure control (such as adjusting hydraulic braking pressure) by calling the bwa_control_pressure(remaining_decel) interface. remaining_decel represents the remaining power. Simultaneously, the deceleration provided by the vehicle's mechanical braking (hydraulic braking) can be set as the remaining power.

[0188] Alternatively, if the bwa_available parameter indicates that BWA is unavailable, the vehicle can check whether the esc_available parameter indicates that ESC is available. If ESC is available, the vehicle can implement ESC pressure control (e.g., through valve adjustment) by calling the esc_control_pressure(remaining_decel) interface. remaining_decel represents the remaining power. Simultaneously, the deceleration provided by the vehicle's mechanical braking (hydraulic braking) can be set as the remaining power.

[0189] Alternatively, the vehicle can execute a degraded strategy (such as triggering emergency braking) when the esc_available parameter indicates that ESC is unavailable.

[0190] In one implementation, for the above-mentioned working condition 2, the vehicle can determine that there is no regenerative braking when the VCU is unavailable, and directly achieve the requested deceleration through the hydraulic system.

[0191] Specifically, the execution process of the second execution function handle_case2(void) in case 2 can include: the vehicle can first obtain the ADAS-requested deceleration. When the bwa_available parameter indicates that BWA is available, the vehicle can implement BWA pressure control (such as adjusting hydraulic brake pressure) by calling the bwa_control_pressure(adas_request) interface. adas_request is the ADAS-requested deceleration. Simultaneously, the deceleration provided by the vehicle's mechanical braking (hydraulic braking) can be set as the ADAS-requested deceleration.

[0192] Alternatively, if the `bwa_available` parameter indicates that BWA is unavailable, the vehicle can check if the `esc_available` parameter indicates that ESC is available. If ESC is available, the vehicle can implement ESC pressure control (e.g., through valve adjustment) by calling the `esc_control_pressure(adas_request)` interface. `adas_request` requests deceleration for ADAS. Furthermore, the deceleration provided by the vehicle's mechanical braking (hydraulic braking) can be set to the deceleration requested by ADAS. Simultaneously, the deceleration provided by the vehicle's regenerative braking (recovering energy via a motor) can be set to 0.0f.

[0193] Alternatively, the vehicle can use the EPB in an emergency when the esc_available parameter indicates that the ESC is unavailable (this needs to be implemented).

[0194] In one implementation, for the above-mentioned working condition 3, when the vehicle can be driven normally and there is no ADAS request, the braking force is released to reduce mechanical wear.

[0195] Specifically, the execution process of the third execution function handle_case3(void) in case 3 can include: the vehicle first determines whether BWA is available based on the bwa_available parameter. If bwa_available is available, then, by calling the epb_control_clamp_force(0.0f, true) interface, the wheel slip ratio is controlled by EPB auxiliary control when ABS is activated. The epb_control_clamp_force() interface is used to implement EPB clamping force control.

[0196] Furthermore, the vehicle can set the deceleration provided by mechanical braking (hydraulic braking) to 0.0f. Simultaneously, the vehicle can set the deceleration provided by regenerative braking (recovering energy via a motor) to 0.0f. Additionally, the vehicle can set the deceleration provided by EPB (electronic parking brake) to 0.0f.

[0197] In one implementation, for the above-mentioned working condition 4, the vehicle can pre-fill the hydraulic pressure before ABS assistance is activated, thereby establishing hydraulic pressure in advance and improving braking response speed.

[0198] Specifically, the execution process of the fourth execution function handle_case4(void) in condition 4 can include: when the vehicle is prompted by g_adas_prefill_request to request prefill and the bwa_available parameter indicates that BWA is available, it can call the bwa_control_pressure(0.5f) interface to perform small pressure prefill of BWA, thereby shortening the subsequent response time. Here, 0.5f is a preset small pressure value.

[0199] In one implementation, for the above-mentioned case 5, after the ABS is activated, the vehicle can use EPB for assistance when insufficient brake fluid occurs, thereby ensuring braking performance. Optionally, the function for case 5 can be denoted as handle_case5(void).

[0200] Specifically, when the abs_active parameter indicates ABS activation, the vehicle is on a low-traction road surface, and the master cylinder brake fluid level is less than 10.0f, the vehicle can use BWA and ESC to collaboratively control fluid replenishment and simultaneously activate EPB auxiliary braking. Optionally, this 10.0f can be a preset fluid level threshold.

[0201] Furthermore, when the `bwa_available` parameter indicates that BWA (Brake Welding) is available and the `esc_available` parameter indicates that ESC (Electronic Stability Control) is available, the vehicle can close the pressure relief valve, begin fluid replenishment, and implement pressure relief valve control. During this process, the vehicle can also invoke EPB (Electronic Brake Parameter) braking control. The vehicle can call the `epb_control_abs_assist(true, 0.2f)` interface to assist in controlling the wheel slip ratio via EPB when ABS is activated. Here, 0.2f can be a preset slip ratio threshold. That is, the vehicle can execute EPB auxiliary control when the wheel slip ratio is greater than 0.2f.

[0202] Otherwise, if the bwa_available parameter indicates that BWA is unavailable, or the esc_available parameter indicates that ESC is unavailable, the vehicle can disable the epb_control_abs_assist(false, 0.0f) interface by calling it.

[0203] In one implementation, the operating condition determination function `determine_operating_case(void)` is used to determine the main operating condition. The specific execution process of this function can include: the vehicle first determines whether the ADAS-requested deceleration is greater than 0.1f. If so, it indicates that the ADAS actively requests deceleration. At this time, if the VCU is available and the maximum deceleration of the VCU is greater than 0.1f, the vehicle can return to the operating mode `BRAKE_MODE_ADAS_ACTIVE`. This operating mode corresponds to operating condition 1. Otherwise, if the VCU is unavailable, or the maximum deceleration of the VCU is less than or equal to 0.1f, the vehicle can return to the operating mode `BRAKE_MODE_ADAS_ACTIVE`. This operating mode corresponds to operating condition 2.

[0204] When the ADAS requests a deceleration of less than or equal to 0.1f, the vehicle can further determine whether ABS is activated and the vehicle is on a low-traction surface. If ABS is activated and the vehicle is on a low-traction surface, the vehicle can return to the operating mode BRAKE_MODE_ABS_ACTIVE. This operating mode is used to indicate condition 5.

[0205] The vehicle can determine whether to request pre-fill when ABS is not activated or when the vehicle is not on a low-traction surface. If the vehicle requests pre-fill, it can return to the operating mode BRAKE_MODE_ADAS_ACTIVE. In this case, the operating mode is used to indicate condition 4.

[0206] The vehicle can return to the BRAKE_MODE_NORMAL operating mode if no prefilling is requested. This operating mode is used to indicate operating condition 3.

[0207] In one implementation, the vehicle can also include a system status update function. This function can be denoted as update_system_status(const system_status_t* new_status). The vehicle can use this function to update the global variable g_sys_status.

[0208] In one implementation, the vehicle can also include a function for setting the prefill request. This function can be denoted as `set_adas_prefill_request(bool enable)`, where `enable` is a parameter value indicating whether the prefill request is true or false.

[0209] In one implementation, the vehicle may also include a function for obtaining the current brake distribution state. This function can be denoted as get_brake_distribution(brake_distribution_t* dist).

[0210] In one implementation, an initialization function can also be set in the vehicle. This initialization function is used to initialize the parameter values ​​in the global variables g_sys_status and g_brake_dist.

[0211] Figure 3 is a structural diagram of a brake booster provided in an embodiment of this application. Based on the embodiments shown in Figures 1 and 2, as shown in Figure 3, the brake booster 300 can be a major component for braking in hydraulic brake-by-wire systems and vehicle electronic stability systems. The brake booster 300 includes a controller 310, a drive assembly 320, and a brake cylinder 330.

[0212] The controller 310 includes a controller housing 311 and a printed circuit board 312. Optionally, the printed circuit board 312 can specifically be a printed circuit board (PCB). The drive assembly 320 may include a bearing 321, a rotor 322, a stator 323, a worm gear 324, a motor housing 325, a bushing 326, and a motor 327. The brake cylinder 330 includes a piston 331, an oil reservoir 332, and a master cylinder housing 333. Optionally, the brake booster 300 may also include a bolt 340.

[0213] The brake booster 300 internally controls the motor 327 in the drive assembly 320 via components on the printed circuit board 312. The stator 323 in the drive assembly 320 is fixedly assembled with the motor housing 325. Bearings 321 and rotor 322 are connected to the worm gear 324. Bearings 321 and rotor 322 are mounted on one side of the worm gear 324. The other side of the worm gear 324 serves as the output end. After a signal is input from the controller 310, bearings 321 drive rotor 322 and worm gear 324 to rotate. A bushing 326 is mounted on the worm gear 324. When the worm gear 324 rotates with the rotor 322, the bushing 326 on the worm gear 324 reciprocates along the axis of the worm gear 324 towards the other output end. A piston 331 is installed inside the main cylinder housing 333 of the brake cylinder 330. The piston 331 is connected to the bushing 326. When the bushing 326 moves, it will drive the piston 331 in the main cylinder housing 333 to reciprocate, thereby achieving the purpose of pressure building.

[0214] Figure 4 is a block diagram of a vehicle longitudinal deceleration control device provided in an embodiment of this application. As shown in Figure 4, the vehicle longitudinal deceleration control device 400 is applied to a vehicle longitudinal deceleration control system, in which an electronic parking brake system is integrated within a hydraulic brake-by-wire system. The vehicle longitudinal deceleration control device 400 includes: a fluid replenishment module, used to control the hydraulic brake-by-wire system to close the wheel-side pressure relief valve and replenish the brake fluid in the master cylinder if it is determined that the brake fluid in the master cylinder of the hydraulic brake-by-wire system is insufficient when the anti-lock braking system is activated over a long distance on a low-adhesion road surface; an auxiliary braking module, used to generate caliper braking information when using the caliper of the electronic parking brake system to brake, based on the hydraulic braking information required by the hydraulic brake-by-wire system to achieve the expected braking effect under the current operating conditions; the caliper braking information includes parameters for achieving the expected braking effect when using the electronic parking brake system; and braking control is performed by the caliper of the electronic parking brake system based on the caliper braking information until the master cylinder reaches the condition for replenishing the brake fluid.

[0215] In one implementation, the fluid replenishment module is used to: determine the number of braking operations performed by the hydraulic brake-by-wire system during intermittent braking based on the current operating conditions; determine the brake fluid consumption based on the basic amount of brake fluid required for basic braking by the hydraulic brake-by-wire system and the number of braking operations; and determine that the brake fluid in the master cylinder is insufficient if the remaining brake fluid in the master cylinder is less than the brake fluid consumption.

[0216] In one implementation, the caliper braking information includes a braking current; an auxiliary braking module is used to: adjust the clamping force of the caliper based on the braking current, so that the caliper brakes by alternating clamping and releasing.

[0217] In one implementation, the auxiliary braking module is used to: monitor the wheel speed of a single wheel of the vehicle and calculate the slip ratio based on the wheel speed; if the slip ratio reaches a threshold value, release the caliper of the electronic parking brake system.

[0218] In one implementation, the auxiliary braking module is configured to: determine the braking deceleration and braking execution time based on the hydraulic braking information; calculate the target braking current for caliper clamping based on the braking deceleration; and generate caliper braking information based on the braking execution time and the target braking current.

[0219] In one implementation, the conditions for completing the brake fluid replenishment include: if the hydraulic brake-by-wire system is available, the condition for completing the brake fluid replenishment is that the brake fluid level in the master cylinder rises to a first threshold; if the electronic stability system is available, the condition for completing the brake fluid replenishment is that the accumulator of the electronic stability system is drained.

[0220] In one implementation, an auxiliary braking module is used to: if both the hydraulic brake-by-wire system and the vehicle electronic stability system are unavailable, perform braking control through the calipers of the electronic parking brake system to achieve the desired braking effect.

[0221] Further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0222] In this embodiment, the vehicle longitudinal deceleration control device is presented in the form of a functional unit. Here, a unit refers to an application-specific integrated circuit (ASIC), a processor and memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0223] Figure 5 is a structural diagram of a controller provided in an embodiment of this application. As shown in Figure 5, the hydraulic brake-by-wire system and the vehicle electronic stability system operate in different controllers within the vehicle. For each controller, the controller 500 includes: one or more processors 501, a memory 502, and interfaces for connecting the various components, including high-speed interfaces and low-speed interfaces. The various components communicate with each other using different buses and can be installed on a common motherboard or otherwise as needed. The processor can process instructions executed within the controller, including instructions stored in or on memory to display graphical information of a GUI on an external input / output device (such as a display device coupled to the interface). In some alternative embodiments, multiple processors and / or multiple buses can be used with multiple memories and multiple memory units, if desired. Similarly, multiple controllers can be connected, each device providing some of the necessary operations (e.g., as a server array, a set of blade servers, or a multiprocessor system). Figure 5 uses a single processor 501 as an example.

[0224] Processor 501 may be a central processing unit, a network processor, or a combination thereof. Processor 501 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0225] The memory 502 stores instructions executable by at least one processor 501 to cause the at least one processor 501 to perform the method shown in the above embodiments.

[0226] Memory 502 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the controller. Furthermore, memory 502 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, memory 502 may optionally include memory remotely located relative to processor 501, and this remote memory may be connected to the controller via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0227] Memory 502 may include volatile memory, such as random access memory; memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; memory 502 may also include combinations of the above types of memory.

[0228] The controller also includes a communication interface 503 for communicating with other devices or communication networks.

[0229] This application also provides a computer-readable storage medium. The methods described in this application can be implemented in hardware or firmware, or implemented as recordable on a storage medium, or implemented as computer code downloaded over a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and subsequently stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, the methods shown in the above embodiments are implemented.

[0230] This application provides a computer program product including computer instructions stored in a computer-readable storage medium. A controller's processor reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the controller to perform the method of any embodiment of this application.

[0231] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and all such modifications and variations fall within the scope defined by the appended claims.

[0232] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, a computer can be, for example, a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email device, game console, tablet computer, wearable device, or any combination of these devices.

[0233] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0234] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0235] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more blocks of the flowchart illustrations and / or one or more blocks of the block diagrams.

[0236] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0237] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more flowcharts and / or one or more block diagrams.

[0238] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0239] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0240] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

[0241] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for longitudinal deceleration control of a vehicle, characterized in that, An application to a vehicle longitudinal deceleration control system, wherein the hydraulic brake-by-wire system of the vehicle longitudinal deceleration control system integrates an electronic parking brake system; the method includes: when the vehicle is on a low-traction road surface and the anti-lock braking system is activated for a long distance, if it is determined that the master cylinder brake fluid in the hydraulic brake-by-wire system is insufficient, controlling the hydraulic brake-by-wire system to close the wheel-side pressure relief valves and controlling the master cylinder to replenish the brake fluid; generating caliper braking information when using the calipers of the electronic parking brake system for braking, based on the hydraulic braking information required by the hydraulic brake-by-wire system to achieve the expected braking effect under the current operating condition; the caliper braking information includes parameters for achieving the expected braking effect when using the electronic parking brake system; and controlling braking through the calipers of the electronic parking brake system based on the caliper braking information until the master cylinder reaches the condition for replenishing the brake fluid.

2. The method according to claim 1, characterized in that, Determining that the master cylinder brake fluid in the hydraulic brake-by-wire system is insufficient includes: determining the number of braking operations performed by the hydraulic brake-by-wire system during intermittent braking based on the current operating conditions; determining the brake fluid consumption based on the basic amount of brake fluid required for basic braking and the number of braking operations; and determining that the master cylinder brake fluid is insufficient if the remaining amount of brake fluid in the master cylinder is less than the brake fluid consumption.

3. The method according to claim 1, characterized in that, The caliper braking information includes braking current; based on the caliper braking information, braking control is performed through the caliper of the electronic parking brake system, including: adjusting the clamping force of the caliper based on the braking current, so that the caliper performs braking through alternating clamping and releasing.

4. The method according to claim 3, characterized in that, The method further includes: monitoring the wheel speed of a single wheel of the vehicle and calculating the slip ratio based on the wheel speed; if the slip ratio reaches a threshold value, releasing the caliper of the electronic parking brake system.

5. The method according to any one of claims 1-4, characterized in that, Based on the hydraulic braking information required for the hydraulic brake-by-wire system to achieve the expected braking effect under the current operating conditions, caliper braking information is generated when the caliper of the electronic parking brake system brakes. This includes: determining the braking deceleration and braking execution time based on the hydraulic braking information; calculating the target braking current for caliper clamping based on the braking deceleration; and generating caliper braking information based on the braking execution time and the target braking current.

6. The method according to any one of claims 1-4, characterized in that, The conditions for completing brake fluid replenishment include: if the hydraulic brake-by-wire system is available, the condition for completing brake fluid replenishment is that the brake fluid level in the master cylinder rises to a first threshold; if the electronic stability system is available, the condition for completing brake fluid replenishment is that the accumulator of the electronic stability system is drained.

7. The method according to any one of claims 1-4, characterized in that, The method further includes: if both the hydraulic brake-by-wire system and the electronic stability control system are unavailable, then there is no need to determine the brake fluid level, and braking control is directly performed through the calipers of the electronic parking brake system.

8. A vehicle longitudinal deceleration control device, characterized in that, An application is made in a vehicle longitudinal deceleration control system, wherein the hydraulic brake-by-wire system of the vehicle longitudinal deceleration control system integrates an electronic parking brake system. The device includes: a fluid replenishment module, used to, under preset operating conditions, if it is determined that the master cylinder of the hydraulic brake-by-wire system has insufficient brake fluid, control the hydraulic brake-by-wire system to close the wheel-side pressure relief valve and control the master cylinder to replenish the brake fluid; and an auxiliary braking module, used to generate caliper braking information when using the calipers of the electronic parking brake system for braking, based on the hydraulic braking information required by the hydraulic brake-by-wire system to achieve the expected braking effect under preset operating conditions; the caliper braking information includes parameters for achieving the expected braking effect when using the electronic parking brake system; and based on the caliper braking information, braking control is performed through the calipers of the electronic parking brake system until the master cylinder meets the conditions for completing the brake fluid replenishment.

9. A vehicle longitudinal deceleration control system, characterized in that, include: The vehicle stability control system, the hydraulic brake-by-wire system, and the electronic parking brake system; the electronic parking brake system is integrated within the hydraulic brake-by-wire system; and the vehicle stability control system stores a backup of the electronic parking brake system; the vehicle stability control system, the hydraulic brake-by-wire system, and the electronic parking brake system can perform the method of any one of claims 1 to 7.

10. A vehicle, characterized in that, The vehicle is equipped with a longitudinal deceleration control system as described in claim 9.

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