Method and system for implementing a vehicle function of turning around in place

Abstract

This invention discloses a method and system for implementing a vehicle's U-turn function, comprising: when the U-turn function is in the off state, the vehicle is powered on, the EHB (Electronic Hydraulic Brake) is fault-free and the function is activated, entering a standby state; when the EHB is fault-free, the driver is present, the vehicle is in Drive (D) gear, the vehicle speed is less than a first threshold, and the steering wheel angle is greater than a second threshold, the EHB function is activated; if the EHB hydraulic system is downgraded and the EPB (Electronic Power Supply) is fault-free, the EPB function is activated. In the EHB function activated state, if the vehicle is powered off or the function is deactivated, the vehicle enters the off state; if the driver is not present, the vehicle is not in Drive (D) gear, the vehicle speed is greater than a third threshold, or the steering wheel angle is less than a fourth threshold, the vehicle returns to the standby state. In the EPB function activated state, if the vehicle is powered off, the function is deactivated, or the EPB malfunctions, the vehicle enters the off state; if the driver is not present, the vehicle is not in Drive (D) gear, the vehicle speed is greater than a fifth threshold, the steering wheel angle is less than a sixth threshold, or the EPB switch is manually activated, the vehicle returns to the standby state.

Description

Technical Field

[0001] This invention relates to the field of vehicle braking electronic control technology, and more specifically, to a method and system for implementing the function of a vehicle making a U-turn on the spot. Background Technology

[0002] The current principle behind the U-turn function in civilian vehicles is as follows: after the driver activates the intelligent assisted U-turn function, they rotate the steering wheel and press the accelerator, triggering the EHB system. In four-wheel drive vehicles, the EHB system applies braking to the outer rear axle wheel while dynamically adjusting the front wheel braking intervention. During this process, the EHB system precisely controls the magnitude and distribution of braking force based on the vehicle's driving status and the driver's intentions, ensuring that the front axle does not lose power due to single-wheel slippage. Simultaneously, by coordinating the power torque output of the front and rear wheels, it effectively reduces the vehicle's turning radius, thereby completing the U-turn maneuver.

[0003] However, existing U-turn technology has significant drawbacks. This function is highly dependent on the EHB (Electronic Braking System). If the EHB system malfunctions, such as a faulty electronic control unit, hydraulic system leaks, or pressure sensor failure, the system cannot build pressure on a single wheel and achieve precise braking control. In this case, the U-turn function will be completely unusable, and the vehicle will be unable to complete the maneuver in narrow roads or complex road conditions, severely limiting the vehicle's handling performance in special scenarios. Due to the lack of redundancy, the EHB system operates continuously during vehicle operation, and the probability of failure due to complex operating conditions and component aging is not negligible. This not only reduces the vehicle's ease of use but also makes drivers hesitant in scenarios where a U-turn might be necessary, worrying about being unable to complete the maneuver due to braking system failure, thus affecting the driving experience. Summary of the Invention

[0004] This invention provides a method and system for implementing the function of turning a vehicle in place, in order to overcome at least one technical problem existing in the prior art.

[0005] According to a first aspect of the present invention, a method for implementing a vehicle U-turn function is provided, comprising:

[0006] When the vehicle's U-turn function is off, if the vehicle is powered on and the EHB hydraulic brake-by-wire system is detected to be fault-free and the U-turn function is activated, the vehicle will enter the U-turn function standby state.

[0007] In the standby state of the U-turn function, if the vehicle is detected to be powered down, the U-turn function is turned off, or the EHB system malfunctions, the U-turn function will enter the off state. If, when the EHB system is functioning correctly, the driver is in position, the vehicle is in drive (D), the vehicle speed is less than a preset first threshold, and the vehicle steering wheel angle is greater than a preset second threshold, the U-turn function will be activated through the EHB system, entering the EHB function activated state, and the EHB system will control the vehicle to perform a U-turn. If the hydraulic system in the EHB system is downgraded and the Electronic Parking Brake (EPB) system is functioning correctly, the EPB function will enter the EPB function activated state, and the EPB system will control the vehicle to perform a U-turn.

[0008] When the EHB function is activated, if the vehicle is detected to be powered down or the U-turn function is deactivated, the U-turn function will be deactivated. If the hydraulic system in the EHB system is detected to be downgraded and the EPB function is fault-free, the EPB function will be activated, and the EPB system will control the vehicle to perform a U-turn. If the driver is not in the correct position, the vehicle is not in D gear, the vehicle speed is greater than a preset third threshold, or the vehicle steering wheel angle is less than a preset fourth threshold, the U-turn function will be in standby mode.

[0009] When the EPB function is activated, if the vehicle is detected to be powered off, the U-turn function is turned off, or the EPB malfunction is detected, the U-turn function will be turned off. If the driver is not in the correct position, the vehicle is not in D gear, the vehicle speed is greater than the preset fifth threshold, the steering wheel angle is less than the preset sixth threshold, or the driver manually pulls the EPB switch, the U-turn function will be turned off.

[0010] In an optional embodiment, after the vehicle is powered on, the EHB system performs a self-test, which includes the electronic control unit, hydraulic system pressure, hydraulic pipeline integrity, and pressure sensor status. When all the above self-test items are fault-free and a signal to activate the U-turn function is received, the system enters the standby state of the U-turn function.

[0011] In an optional embodiment, the preset first threshold is less than the preset third threshold, and the preset second threshold is greater than the preset fourth threshold.

[0012] In the optional embodiment, after the vehicle is powered on, the EHB system performs a self-test that includes at least the electronic control unit, hydraulic system pressure, hydraulic pipeline integrity, and pressure sensor status. When all of the above self-test items are fault-free, the EHB is determined to be fault-free.

[0013] In an optional embodiment, the criteria for determining whether the driver is in position include the vehicle seat pressure sensor detecting that the driver's seat pressure exceeds a predetermined threshold, and the seat belt interface sensor detecting that the seat belt is fastened.

[0014] In an optional embodiment, when the EHB system controls the vehicle to perform a U-turn, the EHB system performs hydraulic braking control on the outer rear axle wheel of the vehicle and adjusts the braking force and distribution in real time according to wheel speed signal, steering wheel angle signal, torque signal and vehicle acceleration signal.

[0015] In an optional embodiment, during the entire process of executing the U-turn function, the vehicle electronic control unit transmits the status information of the U-turn function, including whether the function is enabled, the current function status, the working status of the EHB system and the EPB system, and the stage information of the vehicle's U-turn process, to the instrument for display. The instrument feeds back the driver's operation instructions or other relevant vehicle information to the vehicle electronic control unit.

[0016] According to a second aspect of the present invention, a system for implementing a vehicle U-turn function is provided, which is used in the method for implementing the vehicle U-turn function described above. The system includes:

[0017] The input unit is used to obtain the information required for the U-turn function from the vehicle bus. The information includes the U-turn function activation signal, wheel speed signal, gear signal, torque signal, power status signal, steering wheel angle signal, and driver status signal. After obtaining the above signals, the input unit performs preprocessing operations including filtering and amplification on them and then transmits them to the functional logic unit.

[0018] The functional logic unit, connected to the input and output units, includes an instrument interaction subunit, a drive control subunit, and a brake control subunit. The instrument interaction subunit interacts with the instrument, transmitting the status information of the U-turn function to the instrument and receiving driver operation commands and other vehicle-related information from the instrument. The drive control subunit, based on signals from the input unit and a preset control strategy, controls the drive system to achieve forward rotation of the front wheels and reverse rotation of the rear wheels. During control, it dynamically adjusts the torque output of the front and rear wheels according to the real-time vehicle status and works in conjunction with the brake control subunit to ensure stability and safety during U-turns. When the EHB system is functioning correctly, the brake control subunit uses the EHB system for hydraulic braking control. It controls the hydraulic system to apply braking force to the outer rear axle wheel and adjust front wheel braking intervention based on wheel speed signals, steering wheel angle signals, torque signals, and vehicle acceleration signals. When the EHB system malfunctions, it switches to the EPB system for single-wheel caliper clamping braking control and, based on the vehicle status, controls the EPB system to clamp a single wheel to provide braking force.

[0019] The output unit is used to process and output information related to the U-turn function, including instrument display and interaction, torque control, and braking control of the outer rear wheel via hydraulic or EPB. The instrument display and interaction show the driver whether the U-turn function is activated, the current function status, the working status of the EHB and EPB systems, and information on the stage of the vehicle's U-turn. It also receives the driver's operation commands for the U-turn function via the instrument.

[0020] One embodiment of this specification can achieve at least the following beneficial effects:

[0021] This application presents a technical solution for a U-turn function based on redundant EPB (Electronic Power Braking System). It effectively solves the problem that existing U-turn functions rely on the EHB (Electronic Braking Boots) system, and the function becomes unusable when the EHB system malfunctions. This solution switches to the EPB system when the EHB system fails and cannot build pressure on a single wheel. The EPB provides braking force by clamping the single wheel calipers, ensuring the vehicle can still complete a U-turn in complex and narrow road conditions. This improves the availability of the U-turn function and prevents it from failing due to EHB system malfunction. Under normal circumstances, the EHB system functions. When the hydraulic system in the EHB system degrades, the EPB system seamlessly takes over. A state machine manages different operating states, allowing the system to flexibly switch states based on various conditions such as vehicle power on / off, EHB and EPB system status, driver status, vehicle gear, speed, and steering wheel angle. When making U-turns in narrow roads or adjusting direction in complex road conditions, the system can respond quickly, meeting driving needs under different conditions and improving vehicle handling flexibility and driving experience. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the state machine transitions in the method for implementing the vehicle U-turn function provided in the embodiments of this specification;

[0024] Figure 2 This is a schematic diagram of the structure of a system for implementing the vehicle U-turn function, as provided in the embodiments of this specification. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of one or more embodiments of this specification clearer, the technical solutions of one or more embodiments of this specification will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of them. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of one or more embodiments of this specification.

[0026] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another.

[0027] The braking system of civilian vehicles mainly consists of two parts: the service brake and the parking brake. The service brake is commonly implemented using an Electro-Hydraulic Brake (EHB) system. The EHB system uses electronic signals to precisely control the hydraulic system, thereby achieving precise control of the vehicle's braking and playing a crucial role in deceleration and stopping the vehicle during operation. The parking brake typically uses an Electronic Parking Brake (EPB) system, whose main function is to ensure the vehicle remains stationary when parked, preventing accidental movement due to road slopes, external forces, or other factors, thus ensuring parking safety.

[0028] The principle behind the U-turn function in existing civilian vehicles is as follows: When the driver activates the intelligent assisted U-turn function via a switch, they rotate the steering wheel and press the accelerator. The Brake-by-Hand (EHB) system then applies brakes to the outer rear axle wheel. This method is applicable to four-wheel drive vehicles. During the U-turn, the EHB system also dynamically adjusts the braking intervention of the front wheels. Its purpose is to prevent the front axle from losing power due to single-wheel slippage, and simultaneously, by coordinating the torque output of the front and rear wheels, it effectively reduces the vehicle's turning radius, ultimately completing the U-turn maneuver.

[0029] However, the current U-turn function is highly dependent on the EHB (Emergency Hydraulic Brake) system. If the EHB system malfunctions due to certain abnormalities or faults, such as a failure of the electronic control unit, hydraulic system leaks, or pressure sensor failure, the U-turn function will be unavailable. This limits the vehicle's maneuverability in special situations and causes inconvenience to the driver. In narrow streets, if the EHB system malfunctions when a vehicle needs to make a U-turn, the driver will find it difficult to complete the maneuver, potentially leading to traffic congestion and even affecting driving safety.

[0030] To address the aforementioned technical problems in the existing technology, this application provides a method for implementing a vehicle's on-the-spot U-turn function, which is a redundant on-the-spot U-turn scheme. The vehicle's electronic braking control system integrates the EHB and EPB systems. The input unit collects multiple types of signals, and the functional logic unit makes decisions based on these signals. Under normal conditions, the EHB is responsible for braking; if the EHB malfunctions, the system switches to the EPB. A state machine manages each working state, ensuring that the vehicle can perform on-the-spot U-turns under different operating conditions, thus improving availability and reliability.

[0031] The technical solution of this application will be described in detail below with reference to the accompanying drawings. Figure 1 This diagram illustrates the state machine transitions in the vehicle U-turn function implementation method provided in the embodiments of this specification. The executing entity can be the vehicle electronic control unit (ECU), which receives sensor data, analyzes and processes it according to the preset logic of the state machine, and controls the state switching of the U-turn function and the system operation. As shown in the diagram, when the vehicle's U-turn function is in the off state, if the vehicle is powered on and the EHB (Electronic Brake-by-Wire) system is detected to be fault-free and the U-turn function is activated, the vehicle enters the U-turn function standby state.

[0032] In the standby state of the U-turn function, if the vehicle is detected to be powered down, the U-turn function is turned off, or the EHB system malfunctions, the U-turn function will be turned off. If the EHB system is functioning correctly and the driver is in position, the vehicle is in drive (D), the vehicle speed is less than a preset first threshold, and the vehicle steering wheel angle is greater than a preset second threshold, the U-turn function will be activated through the EHB system, and the EHB system will control the vehicle to perform a U-turn. If the hydraulic system in the EHB system is downgraded and the Electronic Parking Brake (EPB) system is functioning correctly, the EPB system will be activated, and the EPB system will control the vehicle to perform a U-turn.

[0033] When the EHB function is activated, if the vehicle is detected to be powered down or the U-turn function is deactivated, the U-turn function will be deactivated. If the hydraulic system in the EHB system is detected to be downgraded and the EPB function is fault-free, the EPB function will be activated and the EPB system will control the vehicle to perform a U-turn. If the driver is not in the correct position, the vehicle is not in D gear, the vehicle speed is greater than the preset third threshold, or the vehicle steering wheel angle is less than the preset fourth threshold, the U-turn function will be in standby mode.

[0034] When the EPB function is activated, if the vehicle is detected to be powered off, the U-turn function is turned off, or the EPB malfunction is detected, the U-turn function will be turned off. If the driver is not in the correct position, the vehicle is not in D gear, the vehicle speed is greater than the preset fifth threshold, the steering wheel angle is less than the preset sixth threshold, or the driver manually pulls the EPB switch, the U-turn function will be in standby mode.

[0035] Figure 1 The state machine demonstrating the U-turn function precisely controls its operation through different states and transition conditions, ensuring the vehicle can safely and effectively perform U-turns under various circumstances. Figure 1 The state machine for the U-turn function includes OFF, Standby, Active by EHB, and Active by EPB states. By clearly defining the transition conditions between different states, such as the operating status of the EHB and EPB systems, the vehicle's power-on and power-off status, driver operations, and information such as vehicle gear position, speed, and steering wheel angle, the system achieves orderly control of the U-turn function, ensuring that the system responds correctly under various circumstances. Each state is described in detail below.

[0036] OFF State (U-turn Function Off): The OFF state is the initial state when the vehicle is not started or the U-turn function is not activated. At this time, all systems and modules related to U-turns are inactive, performing only basic system self-checks to prepare for possible function activation. The system will only transition from the OFF state to the Standby state when all three conditions are met simultaneously: the vehicle is successfully powered on, the EHB system self-check is fault-free, and the U-turn function is activated. For example, if the vehicle is parked in a parking lot, the power is off, the U-turn function is not activated, and the system is in the OFF state. When the driver gets in and starts the vehicle, the EHB system completes its self-check and finds no faults, and then the U-turn activation button is pressed, the system enters the Standby state.

[0037] Standby State (Standby mode for U-turn): After entering Standby state, the input unit continuously collects various signals, performs preliminary analysis and judgment, and prepares to receive and execute control commands at any time. In this state, the system continuously monitors key information such as driver status, vehicle gear, vehicle speed, and steering wheel angle. When the driver is in position (e.g., the driver is sitting in the driver's seat and fastening the seatbelt, and the vehicle system detects that the driver's relevant operations meet the driving preparation state), the vehicle gear is in D, the vehicle speed is less than the first threshold (e.g., 5 km / h, indicating that the vehicle is at a low speed suitable for U-turn), and the steering wheel angle is greater than the second threshold (e.g., 30 degrees, indicating that the driver intends to make a U-turn), and all four conditions are met, the system jumps from Standby state to Active by EHB state, and the EHB system officially initiates the U-turn operation. If, while in Standby mode, the vehicle loses power (the driver turns off the vehicle's power), the U-turn function is disabled (the driver presses the function disable button again), or an EHB malfunction occurs (a fault is detected through EHB system self-check or other monitoring methods), the system will switch from Standby mode back to OFF mode if any of these conditions are met. Furthermore, when the hydraulic system in the EHB is downgraded (the EHB system detects a problem with its own hydraulic components, such as insufficient hydraulic pressure or hydraulic line leaks) and the EPB is fault-free, the system will switch from Standby mode to Active by EPB mode, activating the EPB system to perform the U-turn function. For example, if the vehicle is started and in Standby mode, the driver prepares, shifts into Drive, and slowly drives while making significant steering wheel turns, the system determines that the conditions are met, and the EHB system begins operation, entering Active by EHB mode. If, at this time, a downgraded EHB hydraulic system is detected but the EPB is normal, the system will switch to Active by EPB mode.

[0038] Active by EHB mode (activated via EHB function): In this mode, the EHB system fully takes over the braking and some drive control functions for U-turns. Based on various signals from the input unit, the EHB system precisely controls the hydraulic system to apply appropriate braking force to the outer rear axle wheel, while dynamically adjusting the braking intervention of the front wheels to prevent slippage and loss of power. The drive system adjusts the torque output to the front and rear wheels according to the actual vehicle conditions and the driver's operational needs, enabling the vehicle to perform U-turns with a smaller turning radius. If any of the following conditions are met: the driver is not in the driver's seat (e.g., leaving the driver's seat), the vehicle is not in drive (D gear is switched to another gear, such as park or reverse, which are not suitable for U-turns), the vehicle speed exceeds the function activation threshold (e.g., 10 km / h, as excessive speed is unsuitable for U-turns and may lead to loss of control or inability to complete the U-turn), or the steering wheel angle is less than the function activation threshold (e.g., less than 10 degrees, indicating the driver may not intend to continue the U-turn or the operation does not meet the requirements), the system will switch from Active by EHB to Standby mode, suspending the U-turn operation and waiting for the driver to readjust the vehicle status or restart the U-turn function. When the hydraulic system in the EHB is downgraded and the EPB is fault-free, the system will switch from Active by EHB to Active by EPB mode, switching braking control to the EPB system, which will continue to perform the U-turn function, ensuring that the U-turn function is not interrupted in the event of a partial failure of the EHB system. If the vehicle is powered off or the U-turn function is disabled, the system will switch from Active by EHB state to Error state, indicating an error that may require fault diagnosis and repair. For example, if the driver suddenly leaves the driver's seat during a U-turn, the system will detect this and immediately switch from Active by EHB state to Standby state. If the EHB hydraulic system malfunctions during the U-turn while the EPB is functioning normally, the system will switch to Active by EPB state to complete the U-turn.

[0039] Active by EPB state (activated via EPB): In this state, the EPB system clamps a single wheel according to instructions, providing necessary braking force. The drive system continues to control the torque output of the front wheels (forward rotation) and rear wheels (reverse rotation) according to a preset control strategy, coordinating with the EPB system's braking force to complete a U-turn. If the driver is not in position, the vehicle is not in drive (D), the vehicle speed exceeds the function activation threshold, or the steering wheel angle is less than the function activation threshold, the system switches from Active by EPB state to Standby state. The EPB system stops clamping the calipers and providing braking force, and the U-turn operation is paused. If the vehicle is powered off, the U-turn function is disabled, or the EPB malfunctions, the system switches from Active by EPB state to OFF state. The EPB system stops working and may indicate an error requiring troubleshooting and repair. For example, if an EPB malfunction is detected during a U-turn, the system will immediately switch to OFF state, stop the U-turn operation, and prompt the driver for inspection.

[0040] Table 1 below summarizes the transition conditions for each state.

[0041] Table 1. State Machine Jump Conditions for U-Take Function

[0042]

[0043] In Table 1, "S-state transition" refers to the transition process between different states in the state machine of the U-turn function. Here, "S" stands for State, and state transition is used to describe the changes in the vehicle's U-turn function from one state to another under different operating conditions.

[0044] This application presents a technical solution for a U-turn function based on redundant EPB (Electronic Power Braking System). It effectively solves the problem that existing U-turn functions rely on the EHB (Electronic Braking Boots) system, and the function becomes unusable when the EHB system malfunctions. This solution switches to the EPB system when the EHB system fails and cannot build pressure on a single wheel. The EPB provides braking force by clamping the single wheel calipers, ensuring the vehicle can still complete a U-turn in complex and narrow road conditions. This improves the availability of the U-turn function and prevents it from failing due to EHB system malfunction. Under normal circumstances, the EHB system functions. When the hydraulic system in the EHB system degrades, the EPB system seamlessly takes over. A state machine manages different operating states, allowing the system to flexibly switch states based on various conditions such as vehicle power on / off, EHB and EPB system status, driver status, vehicle gear, speed, and steering wheel angle. When making U-turns in narrow roads or adjusting direction in complex road conditions, the system can respond quickly, meeting driving needs under different conditions and improving vehicle handling flexibility and driving experience.

[0045] Based on the technical solutions described above, some specific solutions are also provided below, which will be explained in detail.

[0046] In an optional embodiment, after the vehicle is powered on, the EHB system performs a self-test, which includes the electronic control unit, hydraulic system pressure, hydraulic pipeline integrity, and pressure sensor status. When all the above self-test items are fault-free and a signal to activate the U-turn function is received, the system enters the standby state of the U-turn function.

[0047] In this embodiment, the electronic control unit (ECU) performs a self-test after the vehicle is powered on because it is the core control component of the EHB system, acting as the system's "brain." It is responsible for receiving various sensor signals, executing control algorithms, and issuing commands. If the ECU fails, it will affect the system's precise control of the braking process, potentially leading to braking failure or abnormalities. During the self-test, both the hardware and software components can be inspected. For example, when checking the hardware, the system can examine the chips, capacitors, resistors, and other electronic components on the circuit board for short circuits, open circuits, or damage, ensuring the physical integrity and normal operating status of the hardware.

[0048] Meanwhile, since hydraulic system pressure is a key element in realizing braking function, insufficient or unstable hydraulic system pressure will seriously affect braking performance, leading to problems such as slow braking or insufficient braking force. When performing a self-check on the hydraulic system pressure, it can be detected whether the hydraulic pump can start normally and establish a stable pressure range according to design requirements.

[0049] Hydraulic lines are the channels for transmitting brake fluid, and their integrity directly affects the normal operation of the hydraulic system. Therefore, self-tests can be performed on hydraulic lines. Since pressure sensors are used to monitor the pressure status of the hydraulic system in real time and convert the pressure signal into an electrical signal for transmission to the electronic control unit, the electrical performance of the pressure sensors can also be tested during the self-test.

[0050] Therefore, in this embodiment, the system determines that the EHB system is fault-free only when all self-test items, such as the electronic control unit, hydraulic system pressure, hydraulic pipeline integrity, and pressure sensor status, are fault-free. Only then can the EHB system be put into normal use, providing reliable protection for vehicle braking and related functions such as U-turns.

[0051] In an optional embodiment, the preset first threshold is less than the preset third threshold, and the preset second threshold is greater than the preset fourth threshold.

[0052] In the technical solution of this embodiment, the first threshold and the third threshold play a key role in the system's judgment of vehicle status and control function switching during the implementation of the vehicle U-turn function.

[0053] To ensure safety when making a U-turn, the threshold interval between the first and third thresholds needs to be set appropriately. If the interval is too small, even a slight change in speed may trigger a function state switch, making the U-turn unstable and increasing the risk of loss of control. If the interval is too large, the vehicle may continue to make the U-turn at an unsafe speed, also threatening driving safety. For example, taking a common sedan as an example, the first threshold can be set to 5 km / h and the third threshold to 8 km / h. This interval can ensure stable low-speed U-turns while avoiding the dangers of excessive speed, thus ensuring safety. When setting the specific values ​​of the first and third thresholds, factors that can be considered include the vehicle's power performance, the response characteristics of the vehicle's steering system, and differences in driver operating habits. Taking vehicle power performance as an example, different vehicles have different power performance; for example, the engine power and torque output characteristics of high-performance cars and ordinary family cars are significantly different. Vehicles with strong power have larger speed changes in the same amount of time, so a larger margin needs to be reserved when setting the threshold interval to allow the system sufficient time to respond and adjust, ensuring proper coordination between power and braking. Vehicles with weak power have slower speed changes, so the threshold interval can be relatively smaller. For example, sports cars and small electric cars have different thresholds. Sports cars have a larger threshold interval than electric cars to match their respective power performance and achieve stable U-turns.

[0054] In an optional embodiment, the criteria for determining whether the driver is in position include the vehicle seat pressure sensor detecting that the driver's seat pressure exceeds a predetermined threshold, and the seat belt interface sensor detecting that the seat belt is fastened.

[0055] In this embodiment, the driver's presence is a prerequisite for the safe activation and execution of the U-turn function. In this embodiment, the driver's presence is determined by a combination of the detection results from the vehicle seat pressure sensor and the seatbelt interface sensor. The vehicle seat pressure sensor detects the pressure on the vehicle seat; when this pressure exceeds a preset threshold, it indicates that the driver is seated. The purpose of setting the preset threshold in this embodiment is to improve the accuracy of the driver's presence determination. The specific value of the preset threshold needs to consider various factors. On the one hand, it is necessary to eliminate false judgments caused by items placed on the seat; for example, the pressure from a regular backpack or handbag should not cause the system to mistakenly determine that the driver is seated. On the other hand, it is necessary to accommodate the weight differences of drivers of different body types. For example, after statistical analysis based on a large amount of human weight data, the preset threshold can be set at around 30 kg.

[0056] In this embodiment, detecting whether the seatbelt is fastened is an important supplementary basis for determining the driver's presence. Even if the seat pressure sensor detects sufficient pressure in the driver's seat, it cannot be completely determined that the driver is in a normal driving position if the seatbelt is not fastened. This is because fastening the seatbelt is a basic requirement for ensuring driver safety while the vehicle is in motion, and it also reflects, to some extent, whether the driver intends to drive normally. If the driver is not wearing a seatbelt, the vehicle may pose a safety hazard, and in this case, functions such as the U-turn function, which require the driver to be in a safe position to activate, should not be engaged.

[0057] In an optional embodiment, when the EHB system controls the vehicle to perform a U-turn, the EHB system performs hydraulic braking control on the outer rear axle wheel of the vehicle and adjusts the braking force and distribution in real time according to wheel speed signal, steering wheel angle signal, torque signal and vehicle acceleration signal.

[0058] In this embodiment, the steering wheel angle signal is acquired by a steering wheel angle sensor. This sensor reflects the angle and direction the driver turns the steering wheel, which is crucial for the EHB system to adjust the magnitude and distribution of braking force. Based on the steering wheel angle signal, the EHB system can accurately determine whether the driver intends to make a U-turn to the left or right, and the magnitude of the U-turn angle. When the driver turns the steering wheel, the system adjusts the braking force of the outer rear axle wheel accordingly to coordinate with the vehicle's steering maneuver. For example, when the steering wheel is turned sharply to the left, the system increases the braking force of the outer left rear axle wheel, making it easier for the vehicle to turn left.

[0059] In an optional embodiment, during the entire process of executing the U-turn function, the vehicle electronic control unit transmits the status information of the U-turn function, including whether the function is enabled, the current function status, the working status of the EHB system and the EPB system, and the stage information of the vehicle's U-turn process, to the instrument for display. The instrument feeds back the driver's operation instructions or other relevant vehicle information to the vehicle electronic control unit.

[0060] In this embodiment, the vehicle's electronic control unit transmits information about whether the U-turn function is activated to the instrument panel, allowing the driver to intuitively understand the function's status. When the driver presses the U-turn activation button, the vehicle's electronic control unit confirms that the activation conditions are met (such as no EHB system faults, the vehicle being powered on, etc.) and sends a "function activated" signal to the instrument panel. The corresponding indicator light on the instrument panel illuminates or displays a specific symbol, informing the driver that the function has been activated. If the function is not activated, the reason will also be clearly indicated, such as an EHB system fault, to facilitate the driver's troubleshooting.

[0061] When a vehicle makes a U-turn, it goes through different functional states, such as OFF, Standby, Active by EHB, and Active by EPB. The vehicle's electronic control unit can transmit the current functional state to the instrument panel in real time, allowing the driver to understand the vehicle's operating status. For example, in Active by EHB mode, the instrument panel can display that the vehicle is making a U-turn under the control of the EHB system. If it switches to Active by EPB mode, the instrument panel updates the display immediately, allowing the driver to clearly understand the switching status of the braking system and make appropriate adjustments.

[0062] Furthermore, considering that the U-turn process involves multiple stages, such as the preparation stage (adjusting wheel angles and checking system status), the execution stage (the vehicle begins to rotate and turn), and the completion stage (the vehicle completes the U-turn), the vehicle's electronic control unit transmits this stage information to the instrument panel, allowing the driver to monitor the U-turn's progress at any time. During the preparation stage, the instrument panel displays "Preparing for a U-turn, please wait"; during the execution stage, it displays "U-turn in progress" along with information such as the vehicle's rotation direction and speed; and during the completion stage, it displays "U-turn completed," facilitating the driver's understanding of the vehicle's status and improving operational controllability.

[0063] Furthermore, the instrument panel provides the driver with an interface to interact with the vehicle's electronic control unit (ECU). The driver can issue operating commands through the instrument panel, which then feeds these commands back to the ECU. For example, the driver can use a button on the instrument panel to control the activation or deactivation of the U-turn function. The instrument panel promptly feeds these operating commands back to the ECU, which then executes the corresponding actions based on the commands.

[0064] Figure 2 The interactive interface for the U-turn function is demonstrated. This is a complex system encompassing input, processing, and output, with each part working closely together to achieve the vehicle's U-turn capability. It involves multiple key units and signal flows to ensure the system responds accurately to driver intent and vehicle status, including input units, functional logic units, and output units. The input unit acquires various key information from the vehicle bus, such as function activation signals, wheel speed signals, and steering wheel angle signals, processes them, and transmits them to the functional logic unit. The functional logic unit performs logic processing for instrument interaction, drive control, and braking control. The output unit outputs the processed results, including instrument display and interaction, torque control, and braking control of the outer rear wheel via hydraulics or EPB, achieving comprehensive control and information feedback for the vehicle's U-turn function. A detailed introduction to each unit follows.

[0065] The input unit is the information acquisition source for the entire U-turn function. It obtains various key information from the vehicle bus, including the U-turn function activation signal, wheel speed signal, gear signal, torque signal, power status signal, steering wheel angle signal, and driver status signal. The U-turn function activation signal is generated by the driver pressing the U-turn activation button and is the key command to start the function. The wheel speed signal reflects the rotational speed of each wheel in real time and is crucial for the system to determine the vehicle's motion state, stability, and whether the speed conditions for a U-turn are met. The wheel speed signal can be acquired by wheel speed sensors. The power status signal is a set of information related to vehicle power, used to characterize the effectiveness of engine output torque and other power-related states. For example, the power status signal may include information on the effectiveness of the torque signal and other state information related to the vehicle's powertrain. The steering wheel angle signal reflects the driver's steering intention and steering range, providing a basis for the system to calculate the vehicle's steering path and braking force distribution. The gear position signal clearly indicates the vehicle's current gear. Different gears have different effects on U-turns; for example, U-turns are only permitted in a suitable gear, such as a forward gear (e.g., D). The torque signal can specifically include actual torque and driver-demanded torque. Actual torque reflects the engine's actual output torque, while demanded torque reflects the driver's desired vehicle power; it's a command signal sent by the driver to the vehicle control system through the accelerator pedal and other components. When the driver presses the accelerator pedal, the vehicle's electronic control system calculates the driver's desired engine torque output value, i.e., the demanded torque, based on factors such as pedal travel and depress speed. This information on actual torque and driver-demanded torque helps the system precisely control the vehicle's power distribution and braking intervention to achieve a smooth U-turn. After these signals are collected by the input unit, they undergo preprocessing operations such as filtering and amplification to remove noise interference, enhance signal stability and accuracy, and then are transmitted to the functional logic unit.

[0066] The functional logic unit (FLU) is the core processing unit for the U-turn function, responsible for analyzing, calculating, and making decisions on input signals to control vehicle movement. The instrument cluster interaction subunit is responsible for bidirectional information exchange with the vehicle's instrument cluster. On one hand, it transmits the status information of the U-turn function, such as whether the function is activated, whether it is in standby or active mode, and whether it is using the EHB or EPB braking system, to the instrument cluster, allowing the driver to intuitively understand the vehicle's operating status. On the other hand, the instrument cluster also feeds back driver commands, such as adjustments to U-turn function settings or fault warnings from other vehicle systems, to the FLU, influencing its control decisions. The drive control subunit precisely controls the drive system based on signals from the input unit and preset control strategies. During a U-turn, it primarily controls the forward rotation of the front wheels and the reverse rotation of the rear wheels, dynamically adjusting the torque output of the front and rear wheels according to actual vehicle conditions, such as vehicle speed, steering wheel angle, vehicle posture, and driver input requirements. When the vehicle begins a U-turn, the drive system outputs a small amount of torque to slowly initiate rotation based on the current state. As the U-turn progresses, the system adjusts the torque magnitude and distribution in real time based on the vehicle's status, such as wheel slippage and steering smoothness, to ensure stability and controllability during the turn. The braking control subunit is responsible for selecting the appropriate braking control mode based on the EHB system's status. When the EHB system is functioning normally, the braking control subunit uses hydraulic control, following instructions from the functional logic unit, to precisely control the hydraulic system to apply appropriate braking force to the outer rear axle wheel. Simultaneously, it dynamically adjusts the front wheel braking intervention based on vehicle dynamics, such as changes in wheel speed and steering wheel angle, to prevent the front axle from losing power due to single-wheel slippage, ensuring the vehicle can achieve a U-turn with a small turning radius. However, when the EHB system malfunctions, especially when the hydraulic system degrades and cannot build pressure on a single wheel, the braking control subunit automatically switches to EPB control mode. At this point, it directs the EPB system to clamp the calipers on a single wheel. Based on factors such as vehicle speed, gear position, and driver operation, it adjusts the motor output to precisely control the clamping force of the calipers, providing appropriate braking force to achieve the U-turn function. Simultaneously, the brake control subunit monitors the operating status of the EHB and EPB systems in real time. If the EHB system returns to normal or the EPB system malfunctions, it can promptly switch control accordingly, ensuring the reliability and redundancy of the braking system.

[0067] The output unit outputs the results processed by the functional logic unit to achieve actual vehicle control and information display, ensuring effective interaction between the driver and the vehicle. The instrument display and interaction system processes information related to the U-turn and displays it intuitively on the instrument panel. It shows the driver whether the U-turn function has been successfully activated and what stage the vehicle is currently in during the U-turn, such as adjusting wheel angles, rotating the vehicle body, or having already completed the turn. It also displays the operating status of the EHB and EPB systems, such as normal operation, fault status, or switching status. Furthermore, the instrument panel provides interactive functions, allowing the driver to adjust settings for the U-turn function via buttons or menus, such as adjusting the speed mode (fast U-turn or smooth U-turn). These setting adjustments are fed back to the functional logic unit through the output unit, affecting the execution of the U-turn function. Torque control, based on instructions from the functional logic unit, transmits precise torque control signals to the drive system to achieve forward rotation of the front wheels and reverse rotation of the rear wheels. During the U-turn, torque control needs to be continuously adjusted according to the actual vehicle conditions and the driver's actions. When a vehicle begins a U-turn, the torque output may be relatively low. As the vehicle's rotation angle increases, the torque output gradually adjusts to ensure a smooth and accurate U-turn. Simultaneously, torque control needs to coordinate with braking control to prevent excessive wheel slippage or loss of power, ensuring stability and safety during the U-turn. Under normal operating conditions, the output unit transmits the hydraulic control signal from the EHB system to the braking system for precise braking of the outer rear wheel. When the EHB system malfunctions and switches to EPB control, the output unit transmits the EPB system's control signal to the corresponding actuator, causing the EPB system to clamp and control the braking force of a single wheel. Whether using hydraulic or EPB control, the output unit must ensure accurate transmission and execution of the braking control signal and monitor the braking system's operating status in real time, such as braking force and braking effect, feeding this information back to the functional logic unit for further adjustments and optimizations.

[0068] Therefore, in this Figure 2 The demonstration shows the interactive interface of the U-turn function. These units constitute the basic architecture of the U-turn function and are the hardware and logical foundation for the system's operation. Figure 1 The system's operation and state transitions in each state (OFF state, Standby state, Activeby EHB state, Active by EPB state) all depend on Figure 2The information and functional support provided by each unit. For example, in Active by EHB mode, the EHB system, based on wheel speed signals and steering wheel angle signals from the input units, uses the braking control subunit of the functional logic unit to perform hydraulic braking control on the outer rear axle wheels. The signal transmission and function execution involved in this process are all based on... Figure 2 An interactive interface framework.

[0069] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention.

[0070] Those skilled in the art will understand that the modules in the apparatus of the embodiments can be distributed in the apparatus of the embodiments as described in the embodiments, or they can be located in one or more devices different from this embodiment with corresponding changes. The modules of the above embodiments can be combined into one module, or they can be further divided into multiple sub-modules.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for implementing a vehicle's on-the-spot U-turn function, applied to a vehicle electronic control unit, characterized in that, The method includes: When the vehicle's U-turn function is off, if the vehicle is powered on and the EHB hydraulic brake-by-wire system is detected to be fault-free and the U-turn function is activated, the vehicle will enter the U-turn function standby state. In the standby state of the U-turn function, if the vehicle is detected to be powered down, the U-turn function is turned off, or the EHB system malfunctions, the U-turn function will enter the off state. If, when the EHB system is functioning correctly, the driver is in position, the vehicle is in drive (D), the vehicle speed is less than a preset first threshold, and the vehicle steering wheel angle is greater than a preset second threshold, the U-turn function will be activated through the EHB system, entering the EHB function activated state, and the EHB system will control the vehicle to perform a U-turn. If the hydraulic system in the EHB system is downgraded and the Electronic Parking Brake (EPB) system is functioning correctly, the EPB function will enter the EPB function activated state, and the EPB system will control the vehicle to perform a U-turn. When the EHB function is activated, if the vehicle is detected to be powered down or the U-turn function is deactivated, the U-turn function will be deactivated. If the hydraulic system in the EHB system is detected to be downgraded and the EPB function is fault-free, the EPB function will be activated, and the EPB system will control the vehicle to perform a U-turn. If the driver is not in the correct position, the vehicle is not in D gear, the vehicle speed is greater than a preset third threshold, or the vehicle steering wheel angle is less than a preset fourth threshold, the U-turn function will be in standby mode. When the EPB function is activated, if the vehicle is detected to be powered off, the U-turn function is turned off, or the EPB malfunction is detected, the U-turn function will be turned off. If the driver is not in the correct position, the vehicle is not in D gear, the vehicle speed is greater than the preset fifth threshold, the steering wheel angle is less than the preset sixth threshold, or the driver manually pulls the EPB switch, the U-turn function will be turned off.

2. The method for implementing the vehicle U-turn function according to claim 1, characterized in that, After the vehicle is powered on, the EHB system performs a self-test, which includes the electronic control unit, hydraulic system pressure, hydraulic pipeline integrity, and pressure sensor status. When all the above self-test items are fault-free and a signal to activate the U-turn function is received, the system enters the standby state of the U-turn function.

3. The method for implementing the vehicle U-turn function according to claim 1, characterized in that, The preset first threshold is less than the preset third threshold, and the preset second threshold is greater than the preset fourth threshold.

4. The method for implementing the vehicle U-turn function according to claim 1, characterized in that, After the vehicle is powered on, the EHB system performs a self-test that includes at least the electronic control unit, hydraulic system pressure, hydraulic pipeline integrity, and pressure sensor status. If none of the above self-test items are faulty, the EHB is considered fault-free.

5. The method for implementing the vehicle U-turn function according to claim 1, characterized in that, The criteria for determining whether the driver is in position include the vehicle seat pressure sensor detecting that the driver's seat pressure exceeds a predetermined threshold, and the seat belt interface sensor detecting that the seat belt is fastened.

6. The method for implementing the vehicle U-turn function according to claim 1, characterized in that, When the vehicle is controlled by the EHB system to perform a U-turn, the EHB system performs hydraulic braking control on the outer rear axle wheel of the vehicle, and adjusts the braking force and distribution in real time according to wheel speed signal, steering wheel angle signal, torque signal and vehicle acceleration signal.

7. The method for implementing the vehicle U-turn function according to claim 1, characterized in that, During the entire process of performing the U-turn function, the vehicle electronic control unit transmits the status information of the U-turn function, including whether the function is enabled, the current function status, the working status of the EHB system and the EPB system, and the stage information of the vehicle's U-turn process, to the instrument panel for display. The instrument panel feeds back the driver's operation commands or other relevant vehicle information to the vehicle electronic control unit.

8. A system for implementing a vehicle U-turn function, used to implement the method for implementing the vehicle U-turn function as described in claim 1, characterized in that, The system includes: The input unit is used to obtain the information required for the U-turn function from the vehicle bus. The information includes the U-turn function activation signal, wheel speed signal, gear signal, torque signal, power status signal, steering wheel angle signal, and driver status signal. After obtaining the above signals, the input unit performs preprocessing operations including filtering and amplification on them and then transmits them to the functional logic unit. The functional logic unit, connected to the input and output units, includes an instrument interaction subunit, a drive control subunit, and a brake control subunit. The instrument interaction subunit interacts with the instrument, transmitting the status information of the U-turn function to the instrument and receiving driver operation commands and other vehicle-related information from the instrument. The drive control subunit, based on signals from the input unit and a preset control strategy, controls the drive system to achieve forward rotation of the front wheels and reverse rotation of the rear wheels. During control, it dynamically adjusts the torque output of the front and rear wheels according to the real-time vehicle status and works in conjunction with the brake control subunit to ensure stability and safety during U-turns. When the EHB system is functioning correctly, the brake control subunit uses the EHB system for hydraulic braking control. It controls the hydraulic system to apply braking force to the outer rear axle wheel and adjust front wheel braking intervention based on wheel speed signals, steering wheel angle signals, torque signals, and vehicle acceleration signals. When the EHB system malfunctions, it switches to the EPB system for single-wheel caliper clamping braking control and, based on the vehicle status, controls the EPB system to clamp a single wheel to provide braking force. The output unit is used to process and output information related to the U-turn function, including instrument display and interaction, torque control, and braking control of the outer rear wheel via hydraulic or EPB. The instrument display and interaction show the driver whether the U-turn function is activated, the current function status, the working status of the EHB and EPB systems, and information on the stage of the vehicle's U-turn. It also receives the driver's operation commands for the U-turn function via the instrument.

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