Electric vehicle abrupt slope slow descent control method and device and medium

Abstract

The invention discloses an electric vehicle abrupt slope slow descent control method and device and a medium, and relates to the technical field of automobiles. The method comprises the steps that if the opening degree of an accelerator pedal and the opening degree of a brake pedal are zero and the pitch angle continuously exceeds a ramp threshold value, a vehicle enters a sliding mode; if the vehicle speed change rate is continuously positive and exceeds a preset slope threshold value, abrupt slope slow descent is triggered; the output torque of the driving motor is cut off, motor reverse dragging braking is started, and a pre-pressurization mechanism of mechanical braking is synchronously triggered; the vehicle speed at the activation moment is set as the initial vehicle speed, the motor rotating speed, the battery temperature and the vehicle pitch angle are collected in real time, and the corrected target vehicle speed is generated; a total recovery torque is calculated based on a difference between the current vehicle speed and the corrected target vehicle speed. According to the method, the vehicle speed can be automatically controlled when the vehicle goes down the long slope, the vehicle is kept sliding without acceleration, the braking thermal failure caused by frequently stepping on the brake pedal is solved, and the driving safety of the vehicle is improved.

Description

Technical Field

[0001] The present application relates to the field of automotive technology, and in particular to a method, device, and medium for controlling steep slope descent of an electric vehicle. Background Art

[0002] As people's environmental awareness grows, electric vehicles are increasingly gaining market share, and with them, more and more technologies related to electric vehicles are being developed, leading to increasingly stringent safety requirements for electric vehicles. When descending long slopes on mountain roads, frequent braking is required to prevent the vehicle from overspeeding. This can easily lead to brake failure and overheating, compromising the vehicle's braking safety.

[0003] Currently, electric vehicles' steep slope descent control mainly relies on a single motor energy recovery or independent intervention of mechanical braking. Traditional solutions have the following defects: the downhill operating condition is judged only by the vehicle speed change rate, resulting in delayed function activation, especially on continuously undulating roads, which can easily cause the vehicle speed to lose control. The motor recovery and mechanical braking work in a time-sharing manner, and the switching process can easily cause torque mutations, leading to wheel speed fluctuations and even the risk of locking; extreme operating conditions such as sudden changes in battery temperature and motor overheating are not taken into account, and there is a hidden danger of system failure caused by recharging overload.

[0004] Existing patents use slope sensors to predict downhill slopes, but do not solve the problem of mechanical brake overheating and failure on long slopes; some patents also propose motor-hydraulic collaborative braking, but do not establish a dynamic closed-loop control mechanism for the slip rate, and cannot guarantee braking safety when the battery is fully charged.

[0005] Through the above analysis, the problems and defects of the existing technology are as follows:

[0006] In the prior art, electric vehicles suffer from low speed control accuracy, overheating of the mechanical brakes, and loss of slip rate control due to failure of electromechanical brake coordination during long downhill conditions. Summary of the Invention

[0007] The embodiments of the present application provide a method, device and medium for controlling steep slope descent of an electric vehicle, which can solve the problems in the prior art of low speed control accuracy, mechanical brake overheating and slip rate loss caused by failure of electromechanical brake coordination in electric vehicles during long downhill conditions.

[0008] In a first aspect, an embodiment of the present application provides a steep slope descent control method for an electric vehicle, the method comprising: monitoring the pitch angle of the vehicle in real time through an inertial measurement unit, and detecting the opening of the accelerator pedal and the opening of the brake pedal in real time; if the opening of the accelerator pedal and the opening of the brake pedal are zero, the pitch angle continues to exceed the slope threshold, and the vehicle enters a coasting mode; in the coasting mode, if the vehicle speed change rate continues to be positive and exceeds a preset slope threshold, steep slope descent is triggered; the output torque of the drive motor is cut off, the motor reverse braking is started, and the pre-pressurization mechanism of the mechanical brake is triggered simultaneously; the vehicle speed at the activation moment is set as the initial vehicle speed, the motor speed, battery temperature and vehicle pitch angle are collected in real time, and a corrected target vehicle speed is generated; the total recovery torque is calculated based on the difference between the current vehicle speed and the corrected target vehicle speed.

[0009] In one implementation of the present application, the total recovery torque is calculated based on the difference between the current vehicle speed and the corrected target speed, specifically including: calculating the baseline recovery torque based on the difference between the current vehicle speed and the corrected target speed through a variable parameter PID algorithm, wherein the proportional coefficient of the variable parameter PID algorithm is positively correlated with the pitch angle, and the integral coefficient is negatively correlated with the battery recharge current; querying the vehicle speed and coasting recovery torque mapping table to obtain a first torque boundary; calculating the second torque boundary based on the maximum battery recharge current and the real-time voltage; obtaining the instantaneous maximum recovery torque fed back by the motor controller to obtain a third torque boundary; and obtaining the total recovery torque based on the intersection interval of the baseline recovery torque, the first torque boundary, the second torque boundary and the third torque boundary.

[0010] In one implementation of the present application, the instantaneous maximum recovery torque fed back by the motor controller is obtained to obtain the third torque boundary, specifically including: calculating the maximum recharge power of the battery based on the real-time voltage and the maximum recharge current; and converting the maximum recharge power into a torque value in combination with the motor speed.

[0011] In one implementation of the present application, the output torque of the drive motor is cut off, the motor reverse braking is started, and the pre-pressurization mechanism of the mechanical brake is triggered synchronously, specifically including: predicting the ramp length based on the rate of change of the pitch angle, if the predicted length exceeds the critical value, sending the highest priority braking request to the electronic hydraulic braking system; controlling the electronic hydraulic braking system to build up pressure between the brake disc and the brake caliper, so that the brake caliper eliminates the working gap.

[0012] In one implementation of the present application, after calculating the total recovery torque based on the difference between the current vehicle speed and the corrected target vehicle speed, the method also includes: receiving the wheel speed fluctuation signal of the anti-lock braking system in real time, and outputting a compensation instruction for the electronic hydraulic braking system when the wheel speed fluctuation signal exceeds a safety threshold; when requesting the compensation instruction of the electronic hydraulic braking system, allocating the ratio of the motor recovery torque to the hydraulic braking force; and exiting the control of steep slope descent when it is detected that the opening of the accelerator pedal and the opening of the brake pedal are not zero.

[0013] In one implementation of the present application, in coasting mode, if the vehicle speed change rate continues to be positive and exceeds a preset slope threshold, after triggering steep slope descent, the method also includes: calculating the slip rate based on the difference between the current vehicle speed and the revised target vehicle speed, adjusting the motor back-drag braking to make the slip rate within the target range, and monitoring the motor temperature and battery SOC at the same time; when the revised target vehicle speed drops to a safety threshold, the braking force is transferred from the motor back-drag braking to the mechanical braking according to a preset ratio, and the braking force is maintained for a predetermined period of time after the vehicle stops.

[0014] In one implementation of the present application, the slip rate is calculated based on the difference between the current vehicle speed and the corrected target vehicle speed, and the slip rate is kept within the target range by adjusting the motor's back-drag braking. At the same time, the motor temperature and battery SOC are monitored, specifically including: using the vehicle body acceleration data collected by the inertial measurement unit as a reference, and integrating the wheel speed signal to calculate the slip rate; when the motor temperature exceeds the safety limit or the battery SOC is higher than the recovery upper limit, the real-time slip rate is controlled by the electronic stability control system.

[0015] In one implementation of the present application, when the motor temperature exceeds the safety limit or the battery SOC is higher than the recovery upper limit, the real-time slip rate is controlled by the electronic stability control system, specifically including: if the slip rate is lower than the target range, the motor back-drag torque is increased in a step-by-step manner; if the slip rate is higher than the upper limit of the range, a compensation instruction of the electronic hydraulic braking system is requested.

[0016] In a second aspect, an embodiment of the present application further provides a steep slope descent control device for an electric vehicle, the device comprising at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so as to enable the at least one processor to: monitor the pitch angle of the vehicle in real time through an inertial measurement unit, and detect the opening of the accelerator pedal and the opening of the brake pedal in real time; if the opening of the accelerator pedal and the opening of the brake pedal are zero, the pitch angle continuously exceeds the ramp threshold, and the vehicle enters a gliding mode; in gliding mode, if the vehicle speed change rate continues to be positive and exceeds a preset slope threshold, steep slope descent is triggered; the output torque of the drive motor is cut off, the motor reverse braking is started, and the pre-pressurization mechanism of the mechanical brake is triggered simultaneously; the vehicle speed at the activation moment is set as the initial vehicle speed, the motor speed, battery temperature and vehicle pitch angle are collected in real time, and a corrected target vehicle speed is generated; the total recovery torque is calculated based on the difference between the current vehicle speed and the corrected target vehicle speed.

[0017] On the third aspect, the embodiment of the present application also provides a non-volatile computer storage medium for steep slope descent control of an electric vehicle, which stores computer executable instructions, and the computer executable instructions are set to: monitor the pitch angle of the vehicle in real time through an inertial measurement unit, and detect the opening of the accelerator pedal and the opening of the brake pedal in real time; if the opening of the accelerator pedal and the opening of the brake pedal are zero, the pitch angle continues to exceed the slope threshold, and the vehicle enters the coasting mode; in the coasting mode, if the vehicle speed change rate continues to be positive and exceeds the preset slope threshold, steep slope descent is triggered; the output torque of the drive motor is cut off, the motor reverse braking is started, and the pre-pressurization mechanism of the mechanical brake is triggered simultaneously; the vehicle speed at the activation moment is set to the initial vehicle speed, and the motor speed, battery temperature and vehicle pitch angle are collected in real time to generate a corrected target vehicle speed; the total recovery torque is calculated based on the difference between the current vehicle speed and the corrected target vehicle speed.

[0018] The embodiments of the present application provide a method / device and medium for controlling steep slope descent of an electric vehicle, which integrates an inertial measurement unit and the motor back electromotive force to calculate the pitch angle in real time, thereby reducing the slope perception delay; a pre-pressurization mechanism eliminates the working clearance of the brake caliper in advance, thereby shortening the hydraulic braking response time; a slip ratio closed-loop controls the wheel speed fluctuation variance to avoid frequent ABS intervention; a four-dimensional torque boundary decision dynamically constrains the risks of battery overcharging and motor overload; a braking force proportional transfer mechanism prioritizes the use of motor reverse braking to reduce the frequency of mechanical braking; and a variable parameter PID algorithm adaptively adjusts according to the slope / battery status. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0020] Figure 1 A flowchart of a steep slope descent control method for an electric vehicle provided in an embodiment of the present application;

[0021] Figure 2 A steep slope descent activation control flow chart of a steep slope descent control method for an electric vehicle provided in an embodiment of the present application;

[0022] Figure 3 A steep slope descent target speed control flow chart of a steep slope descent control method for an electric vehicle provided in an embodiment of the present application;

[0023] Figure 4 A torque control flow chart of a steep slope descent control method for an electric vehicle provided in an embodiment of the present application;

[0024] Figure 5 A schematic diagram of the internal structure of a steep slope descent control device for an electric vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0026] The embodiments of the present application provide a method, device and medium for controlling steep slope descent of an electric vehicle, which solve the problems in the prior art of low speed control accuracy, mechanical brake overheating and slip rate loss caused by failure of electromechanical brake coordination in electric vehicles during long downhill conditions.

[0027] The technical solutions proposed in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0028] Figure 1 This is a flow chart of a method for controlling steep slope descent of an electric vehicle provided in an embodiment of the present application. Figure 1 As shown, the embodiment of the present application provides a method for controlling steep slope descent of an electric vehicle, which specifically includes the following steps:

[0029] Step 10: Use the inertial measurement unit to monitor the vehicle's pitch angle in real time, and detect the accelerator pedal opening and brake pedal opening in real time;

[0030] The control system of the embodiment of the present application includes a vehicle controller, an anti-lock braking system, a motor controller, a motor, an accelerator pedal, a brake pedal, and a battery system.

[0031] In this step, the vehicle controller detects the driver's driving demand based on the accelerator pedal; the vehicle controller detects the driver's braking demand based on the brake pedal;

[0032] Step 20: If the accelerator pedal opening and the brake pedal opening are zero and the pitch angle continues to exceed the slope threshold, the vehicle enters the coasting mode;

[0033] In this step, if Figure 2 As shown, when the vehicle controller determines that the driver has no driving demand and no braking demand, it enters the coasting mode.

[0034] Step 30: In the coasting mode, if the vehicle speed change rate is continuously positive and exceeds a preset slope threshold, a steep hill descent is triggered;

[0035] Step 40: Cut off the output torque of the drive motor, start the motor reverse braking, and simultaneously trigger the pre-pressurization mechanism of the mechanical brake;

[0036] In this step, the motor controller stops outputting current to the drive motor, causing the motor to switch from the driven state to the free state and no longer provide driving force. In other words, it is necessary to ensure that the torque is cut off in a timely manner to avoid power output in the early stage of braking, which may lead to a decrease in braking efficiency or system conflict. There is a certain delay in the response of the mechanical brake (which needs to overcome the gap between the brake pad and the brake disc and the idle travel of the hydraulic pipeline. The pre-pressurization mechanism applies low pressure to the brake pipeline in advance to eliminate the gap and make the brake pad slightly fit the brake disc, shortening the response time during formal braking. The anti-drag brake takes effect first to provide initial deceleration. After the pre-pressurization is completed, the mechanical brake can quickly intervene to provide sufficient braking force when strong braking is required.

[0037] As an optional embodiment, the output torque of the drive motor is cut off, the motor reverse braking is started, and the pre-pressurization mechanism of the mechanical brake is triggered synchronously. Specifically, it may include: Step 401: predicting the length of the ramp based on the rate of change of the pitch angle. If the predicted length exceeds the critical value, sending a highest priority braking request to the electronic hydraulic braking system; Step 402: controlling the electronic hydraulic braking system to build up pressure between the brake disc and the brake caliper to eliminate the working gap of the brake caliper.

[0038] In this step, when the predicted slope length exceeds the set critical value, the highest priority braking request is sent to the electronic hydraulic braking system. That is, the current slope situation requires immediate braking measures, and the braking request has the highest priority to ensure that the vehicle can brake in time to avoid potential danger.

[0039] Step 50: The vehicle speed at the activation moment is set as the initial vehicle speed, and the motor speed, battery temperature, and vehicle pitch angle are collected in real time to generate a corrected target vehicle speed;

[0040] In this step, the initial vehicle speed serves as a reference value for the target vehicle speed to ensure that subsequent corrections do not deviate from the vehicle's current driving state.

[0041] Furthermore, the embodiment of the present application may also include that after activating the steep slope descent control, the vehicle controller detects the current vehicle speed in real time, and when it is determined that the current vehicle speed is greater than the target vehicle speed, the target vehicle speed remains unchanged; when the current vehicle speed is less than the target speed, the current vehicle speed is used as the target vehicle speed of the steep slope descent control, and the target vehicle speed is updated in real time, such as Figure 3 shown.

[0042] Step 60: Calculate the total regenerative torque based on the difference between the current vehicle speed and the modified target vehicle speed.

[0043] As an optional embodiment, the total regeneration torque is calculated based on the difference between the current vehicle speed and the revised target speed, which may specifically include: Step 601: Based on the difference between the current vehicle speed and the revised target speed, the baseline regeneration torque is calculated using a variable parameter PID (Proportional, Integral, Derivative) algorithm, wherein the proportional coefficient of the variable parameter PID algorithm is positively correlated with the pitch angle, and the integral coefficient is negatively correlated with the battery recharge current; Step 602: Querying a vehicle speed and coasting regeneration torque mapping table to obtain a first torque boundary; Step 603: Calculating a second torque boundary based on the maximum battery recharge current and the real-time voltage; Step 604: Obtaining the instantaneous maximum regeneration torque fed back by the motor controller to obtain a third torque boundary; Step 605: Obtaining the total regeneration torque based on the intersection interval of the baseline regeneration torque, the first torque boundary, the second torque boundary, and the third torque boundary.

[0044] In this step, if Figure 4 As shown, the baseline regenerative torque is a theoretical regenerative torque calculated based on the vehicle's current driving state (speed differential). The regenerative torque is dynamically adjusted based on the speed differential to bring the actual vehicle speed closer to the corrected target. The proportional coefficient is positively correlated with the pitch angle: the pitch angle reflects the road slope and directly affects the vehicle's inertial resistance. If the current speed exceeds the target speed, a stronger regenerative torque is required for effective deceleration. Therefore, the proportional coefficient increases with increasing pitch angle, improving the sensitivity of torque adjustment. When driving downhill, the vehicle is pushed by gravity, and a slight regenerative torque can decelerate. Therefore, the proportional coefficient can be appropriately reduced to avoid a sudden drop in speed due to excessive regenerative force. The integral coefficient is used to eliminate steady-state errors. When the vehicle speed is slightly above the target for a long period of time, torque is increased through integral accumulation, subject to battery status constraints. When the battery recharge current is large, further increasing the integral effect may cause the recharge current to exceed the limit. Therefore, the integral coefficient decreases with increasing recharge current, weakening the integral accumulation effect. When the battery recharge current is small, the integral coefficient can be increased to accelerate the elimination of steady-state errors and improve speed control accuracy. The first torque boundary is the basic regenerative torque constraint based on the vehicle's coasting state, determined by a pre-calibrated vehicle speed-coasting regenerative torque mapping table. The second torque boundary is a constraint based on battery safety, calculated from the maximum battery recharge current and real-time voltage. The core is to prevent battery damage due to overcharging current. The battery recharge power cannot exceed its maximum allowable value. Power is directly related to current and voltage. The relationship between regenerative torque and power is: power = regenerative torque × motor speed / 9550 (P = T × n / 9550, P is in kW, T is N·m, and n is the motor speed r / min); the third torque boundary is the physical limit constraint of the motor itself, determined by the instantaneous maximum regenerative torque fed back in real time by the motor controller.

[0045] Furthermore, excessive regeneration can lead to excessive mechanical stress due to the load-bearing capacity of the motor's mechanical structure, such as the rotor and bearings. The motor controller's current, when regenerating, operates as a generator, and the controller's reverse current output is capped to prevent damage to power components. When the motor is heated, its insulation performance degrades, requiring a reduction in the maximum regeneration torque to protect the windings. Limiting the regeneration torque at the motor hardware level prevents damage from overload.

[0046] As an optional embodiment, the instantaneous maximum recovery torque fed back by the motor controller is obtained to obtain the third torque boundary, which may specifically include: Step 6041: calculating the maximum recharge power of the battery based on the real-time voltage and the maximum recharge current; Step 6042: converting the maximum recharge power into a torque value in combination with the motor speed.

[0047] As an optional embodiment, after calculating the total recovery torque based on the difference between the current vehicle speed and the corrected target vehicle speed, the method may further include: receiving the wheel speed fluctuation signal of the anti-lock braking system in real time, and outputting a compensation instruction for the electronic hydraulic braking system when the wheel speed fluctuation signal exceeds a safety threshold; allocating the ratio of the motor recovery torque to the hydraulic braking force when requesting the compensation instruction for the electronic hydraulic braking system; and exiting the control of steep slope descent when it is detected that the opening of the accelerator pedal and the opening of the brake pedal are not zero.

[0048] During this step, when descending a steep slope, regenerative braking by the electric motor may cause wheel slip due to low road adhesion. At this point, the ABS (Anti-lock Braking System) monitors abnormal wheel speed fluctuations in real time. If the wheel speed fluctuation signal exceeds a safety threshold, the system determines that the wheel is at risk of locking and immediately sends a compensation command to the electronic hydraulic braking system. By precisely controlling the brake line pressure, the electric motor regenerative torque at the corresponding wheel is reduced to prevent further slip and ensure braking stability. When the electronic hydraulic braking system intervenes to compensate, it dynamically adjusts the proportion of the two braking forces based on road conditions, balancing energy recovery with braking safety. On high-adhesion, dry asphalt surfaces, the electric motor regenerative torque is prioritized, reducing the use of hydraulic braking to maximize energy recovery efficiency and reduce brake pad wear. On low-adhesion surfaces like ice, snow, and mud, the proportion of electric motor regenerative torque is reduced, and hydraulic braking force is increased, leveraging the instantaneous response of hydraulic braking to ensure reliable braking.

[0049] As an optional embodiment, in coasting mode, if the vehicle speed change rate remains positive and exceeds a preset slope threshold, triggering steep slope descent, the method may further include: calculating the slip ratio based on the difference between the current vehicle speed and the revised target speed, adjusting the motor back-drag braking to keep the slip ratio within the target range, and monitoring the motor temperature and battery SOC (State Of Charge); when the revised target speed drops to a safety threshold, transferring the braking force from the motor back-drag braking to the mechanical braking according to a preset ratio, and maintaining the braking force for a predetermined period of time after the vehicle comes to a stop.

[0050] In this step, when the corrected target vehicle speed drops to the safety threshold, the braking force is transferred from the motor back-drag braking to the mechanical braking according to a preset ratio. After the vehicle comes to a complete stop, the mechanical braking maintains the braking force for a predetermined period of time to prevent the vehicle from slipping.

[0051] As an optional embodiment, the slip ratio is calculated based on the difference between the current vehicle speed and the modified target speed. The slip ratio is brought into the target range by adjusting the motor's back-braking action. Meanwhile, the motor temperature and battery SOC are monitored. Specifically, the slip ratio is calculated based on the vehicle body acceleration data collected by the inertial measurement unit and integrated with the wheel speed signal. When the motor temperature exceeds the safety limit or the battery SOC is higher than the recovery upper limit, the real-time slip ratio is controlled by the electronic stability control system.

[0052] In this step, the vehicle body acceleration collected by the inertial measurement unit (IMU) is used as a reference, combined with the wheel speed sensor signal, to calculate the slip rate through algorithms such as Kalman filtering to improve calculation accuracy. The vehicle body speed is inferred by the IMU, and the wheel speed is the actual value measured by each wheel speed sensor. When the motor temperature exceeds the safety limit, the motor's anti-drag braking torque is reduced to prevent insulation aging or permanent magnet demagnetization. When the motor or battery is limited, such as due to overheating or overcharging, the slip rate control task is transferred to the electronic stability control system, which adjusts the wheel braking force through hydraulic braking to ensure that the slip rate remains within the target range.

[0053] As an optional embodiment, when the motor temperature exceeds the safety limit or the battery SOC is higher than the recovery upper limit, the real-time slip rate is controlled by the electronic stability control system, specifically including: if the slip rate is lower than the target range, the motor back-drag torque is increased in a step-by-step manner; if the slip rate is higher than the upper limit of the range, a compensation instruction is requested from the electronic hydraulic braking system.

[0054] In this step, the motor's reverse torque is increased in a step-by-step manner to enhance the braking strength. When the torque exceeds the upper limit of the range, the electronic hydraulic braking system is immediately requested to intervene to suppress wheel slippage by increasing the hydraulic braking force.

[0055] The above is an embodiment of the method proposed in this application. Based on the same inventive concept, this application embodiment also provides an electric vehicle steep slope descent control device, the structure of which is as follows: Figure 5shown.

[0056] Figure 5 This is a schematic diagram of the internal structure of an electric vehicle steep slope descent control device provided in an embodiment of the present application. Figure 5 As shown, the equipment includes:

[0057] at least one processor 501;

[0058] and, a memory 502 in communication with the at least one processor;

[0059] Among them, the memory 502 stores instructions that can be executed by at least one processor, and the instructions are executed by at least one processor 501 to enable the at least one processor 501 to: monitor the pitch angle of the vehicle in real time through the inertial measurement unit, and detect the opening of the accelerator pedal and the opening of the brake pedal in real time; if the opening of the accelerator pedal and the opening of the brake pedal are zero, the pitch angle continues to exceed the slope threshold, and the vehicle enters the coasting mode; in the coasting mode, if the vehicle speed change rate is continuously positive and exceeds the preset slope threshold, steep slope descent is triggered; the output torque of the drive motor is cut off, the motor reverse braking is started, and the pre-pressurization mechanism of the mechanical brake is triggered simultaneously; the vehicle speed at the activation moment is set as the initial vehicle speed, the motor speed, battery temperature and vehicle pitch angle are collected in real time, and a corrected target vehicle speed is generated; the total recovery torque is calculated based on the difference between the current vehicle speed and the corrected target vehicle speed.

[0060] Some embodiments of the present application provide corresponding Figure 1 A non-volatile computer storage medium for electric vehicle steep slope descent control stores computer-executable instructions, wherein the computer-executable instructions are configured to: monitor the vehicle's pitch angle in real time through an inertial measurement unit, and detect the accelerator pedal opening and the brake pedal opening in real time; if the accelerator pedal opening and the brake pedal opening are zero, and the pitch angle continuously exceeds the slope threshold, the vehicle enters a coasting mode; in the coasting mode, if the vehicle speed change rate is continuously positive and exceeds a preset slope threshold, the steep slope descent is triggered; the drive motor output torque is cut off, the motor reverse braking is started, and the pre-pressurization mechanism of the mechanical brake is triggered simultaneously; the vehicle speed at the activation moment is set as the initial vehicle speed, the motor speed, battery temperature and vehicle pitch angle are collected in real time, and a corrected target vehicle speed is generated; and the total recovery torque is calculated based on the difference between the current vehicle speed and the corrected target vehicle speed.

[0061] The various embodiments in this application are described in a progressive manner. Similar portions between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from the other embodiments. In particular, the IoT device and media embodiments are generally similar to the method embodiments, so their description is relatively simple. For relevant portions, refer to the description of the method embodiments.

[0062] The system and medium provided in the embodiments of the present application correspond one-to-one to the method. Therefore, the system and medium also have similar beneficial technical effects to their corresponding methods. Since the beneficial technical effects of the method have been described in detail above, the beneficial technical effects of the system and medium will not be repeated here.

[0063] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0064] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0065] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0066] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0067] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0068] Memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. Memory is an example of a computer-readable medium.

[0069] Computer-readable media includes permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0070] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0071] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A steep slope descent control method for an electric vehicle, characterized in that: The method comprises: The inertial measurement unit monitors the vehicle's pitch angle in real time, and detects the accelerator pedal and brake pedal opening degrees in real time; If the accelerator pedal opening and the brake pedal opening are zero and the pitch angle continues to exceed the slope threshold, the vehicle enters the coasting mode; In the coasting mode, if the vehicle speed change rate is continuously positive and exceeds a preset slope threshold, a steep hill descent is triggered; Cut off the output torque of the drive motor, start the motor reverse braking, and simultaneously trigger the pre-pressurization mechanism of the mechanical brake; The vehicle speed at the activation moment is set as the initial speed, and the motor speed, battery temperature, and vehicle pitch angle are collected in real time to generate a corrected target speed. The total regenerative torque is calculated based on the difference between the current vehicle speed and the revised target vehicle speed.

2. The method for controlling a steep slope descent of an electric vehicle according to claim 1, characterized in that: The total regenerative torque is calculated based on the difference between the current vehicle speed and the modified target vehicle speed, specifically including: Based on the difference between the current vehicle speed and the revised target vehicle speed, a reference regenerative torque is calculated using a variable parameter PID algorithm, wherein a proportional coefficient of the variable parameter PID algorithm is positively correlated with the pitch angle, and an integral coefficient is negatively correlated with the battery recharge current; Querying a vehicle speed and coasting recovery torque mapping table to obtain a first torque boundary; Calculating a second torque limit according to the maximum battery recharge current and the real-time voltage; Obtaining the instantaneous maximum recovery torque fed back by the motor controller to obtain a third torque boundary; A total regeneration torque is obtained according to an intersection interval of the base regeneration torque, the first torque boundary, the second torque boundary, and the third torque boundary.

3. The method for controlling a steep slope descent of an electric vehicle according to claim 2, characterized in that: The step of obtaining the instantaneous maximum recovery torque fed back by the motor controller to obtain the third torque boundary specifically includes: Calculate the maximum recharge power of the battery according to the real-time voltage and the maximum recharge current; Combined with the motor speed, the maximum recharge power is converted into a torque value.

4. The method for controlling a steep slope descent of an electric vehicle according to claim 1, wherein: Cut off the output torque of the drive motor, start the motor anti-drag braking, and simultaneously trigger the pre-pressurization mechanism of the mechanical brake, specifically including: predicting a ramp length based on a rate of change of the pitch angle, and sending a highest priority braking request to the electronic hydraulic braking system if the predicted length exceeds a critical value; The electronic hydraulic brake system is controlled to build up pressure between the brake disc and the brake caliper, so that the brake caliper eliminates the working gap.

5. The method for controlling a steep slope descent of an electric vehicle according to claim 1, characterized in that: After calculating the total regenerative torque based on the difference between the current vehicle speed and the modified target vehicle speed, the method further includes: receiving a wheel speed fluctuation signal of an anti-lock braking system in real time, and outputting a compensation instruction for an electronic hydraulic braking system when the wheel speed fluctuation signal exceeds a safety threshold; When requesting a compensation instruction for the electronic hydraulic brake system, allocating a ratio between the motor recovery torque and the hydraulic braking force; When it is detected that the opening of the accelerator pedal and the opening of the brake pedal are not zero, the steep slope descent control is exited.

6. The method for controlling a steep slope descent of an electric vehicle according to claim 1, characterized in that: In the coasting mode, if the vehicle speed change rate is continuously positive and exceeds a preset slope threshold, triggering a steep hill descent, the method further includes: Calculating a slip ratio based on a difference between a current vehicle speed and a modified target vehicle speed, adjusting the motor's back-braking to keep the slip ratio within a target range, and simultaneously monitoring the motor's temperature and the battery's state of charge (SOC); When the modified target vehicle speed drops to a safety threshold, the braking force is transferred from the motor back-drag braking to the mechanical braking according to a preset ratio, and the braking force is maintained for a predetermined time after the vehicle stops.

7. The method for controlling a steep slope descent of an electric vehicle according to claim 6, characterized in that: The method of calculating the slip ratio based on the difference between the current vehicle speed and the modified target vehicle speed, adjusting the motor back-braking to keep the slip ratio within the target range, and monitoring the motor temperature and battery SOC at the same time specifically includes: The slip ratio is calculated by fusing the wheel speed signal with the vehicle body acceleration data collected by the inertial measurement unit as a reference; When the motor temperature exceeds a safety limit or the battery SOC is higher than a recovery upper limit, the real-time slip rate is controlled by an electronic stability control system.

8. The method for controlling a steep slope descent of an electric vehicle according to claim 7, characterized in that: When the motor temperature exceeds a safety limit or the battery SOC is higher than a recovery upper limit, the real-time slip rate is controlled by an electronic stability control system, specifically including: If the slip ratio is lower than the target range, increasing the motor anti-drag torque in a step-by-step manner; If the slip ratio is higher than an upper limit of the range, a compensation instruction of the electronic hydraulic brake system is requested.

9. A steep slope descent control device for an electric vehicle, characterized in that: The device comprises: at least one processor; and, a memory communicatively coupled to the at least one processor; The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to: The inertial measurement unit monitors the vehicle's pitch angle in real time, and detects the accelerator pedal and brake pedal opening degrees in real time; If the accelerator pedal opening and the brake pedal opening are zero and the pitch angle continues to exceed the slope threshold, the vehicle enters the coasting mode; In the coasting mode, if the vehicle speed change rate is continuously positive and exceeds a preset slope threshold, a steep hill descent is triggered; Cut off the output torque of the drive motor, start the motor reverse braking, and simultaneously trigger the pre-pressurization mechanism of the mechanical brake; The vehicle speed at the activation moment is set as the initial speed, and the motor speed, battery temperature, and vehicle pitch angle are collected in real time to generate a corrected target speed. The total regenerative torque is calculated based on the difference between the current vehicle speed and the revised target vehicle speed.

10. A non-volatile computer storage medium for controlling steep slope descent of an electric vehicle, storing computer executable instructions, characterized in that: The computer executable instructions are configured to: The inertial measurement unit monitors the vehicle's pitch angle in real time, and detects the accelerator pedal and brake pedal opening degrees in real time; If the accelerator pedal opening and the brake pedal opening are zero and the pitch angle continues to exceed the slope threshold, the vehicle enters the coasting mode; In the coasting mode, if the vehicle speed change rate is continuously positive and exceeds a preset slope threshold, a steep hill descent is triggered; Cut off the output torque of the drive motor, start the motor reverse braking, and simultaneously trigger the pre-pressurization mechanism of the mechanical brake; The vehicle speed at the activation moment is set as the initial speed, and the motor speed, battery temperature, and vehicle pitch angle are collected in real time to generate a corrected target speed. The total regenerative torque is calculated based on the difference between the current vehicle speed and the revised target vehicle speed.

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