Electric trackless rubber-tyred vehicle line control brake system

Abstract

The application provides a line control brake system of an electric trackless rubber-tyred vehicle, and relates to the field of vehicle brake control systems.The line control brake system comprises an electro-hydraulic proportional control brake valve which adjusts output brake pressure according to an input control current value; a set of electro-hydraulic proportional control brake valves is arranged for each hydraulic brake, and the outlet of the electro-hydraulic proportional control brake valve is connected to the inlet of the hydraulic brake; a pressure sensor is used to collect actual brake pressure of the corresponding hydraulic brake; a line control brake controller is in communication connection with the electro-hydraulic proportional control brake valve and the pressure sensor, and is configured to: according to brake power demand, decompose brake power into hydraulic brake power and motor brake power; send control current to each electro-hydraulic proportional control brake valve, and send brake torque information to a motor controller to control a driving motor to implement electric braking.The application avoids the problem that in the prior art, brake pressure of a foot pedal brake is only determined by mechanical stroke of the pedal, and improves brake control precision and stability.

Description

Technical Field

[0001] This invention relates to the field of vehicle braking control systems, specifically to a wire-controlled braking system for an electric trackless rubber-tired vehicle. Background Technology

[0002] The braking system is a very important core system for trackless rubber-tired vehicles. The existing braking systems of electric trackless rubber-tired vehicles are mainly divided into service braking systems and parking braking systems. The service braking system is the core actuator for decelerating and stopping the electric trackless rubber-tired vehicle during operation, while the parking braking system is used to reliably stop the vehicle after it has come to a standstill.

[0003] The vehicle braking system (such as the energy-saving hydraulic braking system of the explosion-proof electric rubber-wheeled vehicle with publication number CN106627545A) typically uses a foot pedal to push the valve core of a hydraulic valve, outputting brake fluid to the brake. The depth of foot pedal depressing adjusts the opening of the hydraulic valve, controlling the brake fluid pressure output by the hydraulic valve, thereby determining the braking force of the brake. This solution has the following problems:

[0004] 1. The hydraulic line from the foot valve to the wet brake is relatively long, resulting in a longer response time for the service brake and affecting the braking effect;

[0005] 2. When the foot pedal is fully depressed, the wheels may lock up, causing skidding.

[0006] 3. Braking pressure is determined solely by the mechanical travel of the foot pedal, and cannot achieve continuous and precise closed-loop adjustment of braking force like current control. Summary of the Invention

[0007] The present invention provides a line-controlled braking system for an electric trackless rubber-tired vehicle to solve at least one of the technical problems mentioned in the background art.

[0008] To solve the above-mentioned technical problems, the present invention discloses a wire-controlled braking system for an electric trackless rubber-tired vehicle, comprising:

[0009] Electro-hydraulic proportional control brake valve: configured to adjust the output braking pressure according to the input control current value;

[0010] Multiple hydraulic brakes: Each hydraulic brake is set up one-to-one with each wheel of the electric trackless rubber-tired vehicle, and each hydraulic brake is set up with a set of electro-hydraulic proportional control brake valves. The outlet of the electro-hydraulic proportional control brake valves is connected to the inlet of the hydraulic brake.

[0011] Pressure sensor: Installed on each electro-hydraulic proportional control brake valve, used to collect the actual braking pressure of the corresponding hydraulic brake;

[0012] The wire-controlled brake controller is communicatively connected to the electro-hydraulic proportional control brake valve and the pressure sensor, and is configured as follows:

[0013] Based on the braking power requirements, the braking force is decomposed into hydraulic braking force and electric braking force; control current is sent to each electro-hydraulic proportional control brake valve to control the braking pressure of each hydraulic brake, and braking torque information is sent to the motor controller to control the drive motor to implement electric braking;

[0014] It receives feedback from pressure sensors on the actual braking pressure of each wheel to achieve closed-loop control.

[0015] Preferably, the hydraulic brake is a wet brake.

[0016] Preferably, the brake-by-wire controller is connected to the vehicle controller via CAN.

[0017] Preferably, the outlet of the electro-hydraulic proportional control brake valve is connected to the inlet of the hydraulic brake via a pipeline, or is directly attached to the inlet of the hydraulic brake via a plate.

[0018] Preferably, the braking force requirement of the brake-by-wire controller comes from a foot potentiometer or a remote control signal.

[0019] Preferably, it also includes a hydraulic system, the hydraulic system comprising:

[0020] A hydraulic pump and an accumulator charging valve, wherein the outlet of the hydraulic pump is connected to the inlet of the accumulator charging valve;

[0021] Accumulator 1 and Accumulator 2: The inlets of Accumulator 1 and Accumulator 2 are connected to the outlets of the accumulator charging valves, respectively. The outlets of Accumulator 1 and Accumulator 2 are connected to the inlets of the mechanical hydraulic brake pedal valves via pipelines. Accumulator 1 supplies brake fluid to the electro-hydraulic proportional control brake valves of the left and right front wheels, respectively, and Accumulator 2 supplies brake fluid to the electro-hydraulic proportional control brake valves of the left and right rear wheels, respectively. The outlet of the mechanical hydraulic brake pedal valve is connected to the internal shuttle valve of the electro-hydraulic proportional control brake valve. The mechanical hydraulic brake pedal valve is activated by the driver.

[0022] Preferably, the brake-by-wire controller decomposes the braking force into hydraulic braking force and electric motor braking force based on the braking power demand, the current vehicle speed, and relevant parameters of the drive motor.

[0023] Preferably, it also includes a memory, which stores the standard drive characteristics of the motor corresponding to the current electric trackless rubber-wheeled vehicle; the standard drive characteristics of the motor are a calibration relationship of "drive motor current - standard wheel speed - standard vehicle speed - standard drive motor torque";

[0024] The brake-by-wire controller includes:

[0025] Receiver module: Used to receive vehicle speed and drive motor related parameters sent by the vehicle controller. The drive motor related parameters include: drive motor speed and drive motor torque.

[0026] Efficiency Analysis Module: Used to determine the motor torque coefficient before braking based on the current and torque of the drive motor before braking and the standard drive characteristics of the motor.

[0027] Transmission analysis module: Determines the "transmission-vehicle speed matching coefficient" before braking based on the current drive motor speed and vehicle speed before braking;

[0028] Current analysis module: used to determine the current margin coefficient before braking by combining the theoretical maximum allowable braking current corresponding to the drive motor;

[0029] Electric Braking Distribution Analysis Module: Used to determine the initial electric braking participation ratio for the current braking based on the motor torque coefficient before the current braking, the "transmission-vehicle speed matching coefficient" before the current braking, and the current margin coefficient before the current braking;

[0030] Braking Analysis Module: Used to determine the initial electric braking torque by combining braking power demand and the initial electric braking participation ratio of the current braking; and to determine the target electric braking torque and hydraulic braking torque by combining the initial electric braking torque, the motor torque coefficient before the current braking, the "transmission-vehicle speed matching coefficient" before the current braking, the standard drive characteristics of the motor, and the theoretical maximum allowable braking current corresponding to the drive motor.

[0031] Preferably, the memory also stores the thermal characteristics of the motor corresponding to the current electric trackless rubber-wheeled vehicle, and the motor thermal characteristics are a calibration relationship of "drive motor current - standard temperature rise rate of the key temperature zone of the drive motor"; the relevant parameters of the drive motor also include the temperature of the key temperature zone of the drive motor.

[0032] The brake-by-wire controller also includes a thermal analysis module, which includes:

[0033] Analysis Unit 1: Determine the standard temperature rise rate of each key temperature zone corresponding to the current braking drive motor current based on the current braking drive motor current and motor thermal characteristics.

[0034] Calculation unit: used to calculate the actual temperature rise rate of each critical temperature zone before braking based on the current critical temperature zone temperature of the drive motor before braking; and to determine the temperature rise rate coefficient of each critical temperature zone by combining the standard temperature rise rate of the critical temperature zone corresponding to the current driving current before braking.

[0035] Analysis Unit 2: Used to determine the theoretical maximum allowable braking current of the drive motor based on the current critical temperature zone temperature and temperature rise rate coefficient of the drive motor before braking, and the target braking time;

[0036] When the temperature rise rate coefficient of any critical temperature zone exceeds the preset coefficient, the brake-by-wire controller generates a corresponding alarm message and sends it to the vehicle controller.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] This invention employs an electro-hydraulic proportional control brake valve, with each hydraulic brake corresponding to an independent electro-hydraulic proportional control valve. This valve is directly integrated into / located near the inlet of each hydraulic brake, significantly shortening the hydraulic line length and solving the problem of long hydraulic lines and response times in existing technologies, particularly the "long hydraulic lines from the foot pedal valve to the wet brake," thus significantly improving braking response speed. Simultaneously, by controlling the current to regulate the output pressure, continuous and precise closed-loop regulation of braking force is achieved, avoiding the limitation of existing technologies where "braking pressure is solely determined by the pedal's mechanical travel," resulting in a substantial improvement in control accuracy and stability.

[0039] Each hydraulic brake corresponds to a set of electro-hydraulic proportional control valves, which can control different braking torques for each tire according to actual needs, so as to achieve anti-lock braking and anti-skid functions.

[0040] The braking force requirement of the brake-by-wire controller comes from the foot potentiometer (local operation) or the remote control signal (remote drive-by operation), which can realize remote vehicle control and, in conjunction with the intelligent driver assistance system, realize assisted driving.

[0041] The brake-by-wire controller is connected to the vehicle controller via CAN to acquire data such as vehicle speed, motor speed, and torque in real time, and sends actual braking data to the vehicle controller to control the brake lights, warning lights, and voice alarms.

[0042] Each electro-hydraulic proportional control brake valve is equipped with a pressure sensor to collect the actual braking pressure of each tire in real time and feed it back to the brake-by-wire controller to achieve closed-loop control and more precise control. Attached Figure Description

[0043] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0044] Figure 1 This is a schematic diagram of the electric trackless rubber-tired vehicle line control braking system of the present invention;

[0045] Figure 2 This is a schematic diagram of one embodiment of the hydraulic system of the present invention.

[0046] In the diagram: 1. Hydraulic pump; 2. Accumulator charging valve; 3.1. Accumulator I; 3.2. Accumulator II; 4. Mechanical hydraulic brake foot valve; 5.1. Electro-hydraulic proportional control brake valve I; 5.2. Electro-hydraulic proportional control brake valve II; 5.3. Electro-hydraulic proportional control brake valve III; 5.4. Electro-hydraulic proportional control brake valve IV; 6.1. Pressure sensor I; 6.2. Pressure sensor II; 6.3. Pressure sensor III; 6.4. Pressure sensor IV; 6.5. Pressure sensor V; 6.6. Pressure sensor VI; 7.1. Wet brake I; 7.2. Wet brake II; 7.3. Wet brake III; 7.4. Wet brake IV; 8. Hydraulic pump motor. Detailed Implementation

[0047] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0048] Furthermore, in this invention, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the invention. They are merely used to distinguish components or operations described using the same technical terms and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions and features of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If a combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0049] The present invention provides the following embodiments:

[0050] Example 1: This embodiment of the invention provides a wire-controlled braking system for an electric trackless rubber-tired vehicle, such as... Figures 1-2 As shown, it includes:

[0051] Electro-hydraulic proportional control brake valve: configured to adjust the output braking pressure according to the input control current value;

[0052] Multiple hydraulic brakes: Each hydraulic brake is set up one-to-one with each wheel of the electric trackless rubber-tired vehicle. Each hydraulic brake is equipped with a set of electro-hydraulic proportional control brake valves. The outlet of the electro-hydraulic proportional control brake valves is connected to the inlet of the hydraulic brakes. Each electro-hydraulic proportional control brake valve is arranged near each hydraulic brake.

[0053] Pressure sensor: Installed on each electro-hydraulic proportional control brake valve, used to collect the actual braking pressure of the corresponding hydraulic brake;

[0054] The wire-controlled brake controller is communicatively connected to the electro-hydraulic proportional control brake valve and pressure sensor, and is configured as follows:

[0055] Based on the braking power requirements, the braking force is decomposed into hydraulic braking force and electric braking force (existing decomposition methods can be used); control current is sent to each electro-hydraulic proportional control brake valve to control the braking pressure of each hydraulic brake, and braking torque information is sent to the motor controller to control the drive motor to implement electric braking; the brake-by-wire controller can decompose the braking force into hydraulic braking force and electric braking force (and can realize energy recovery through electric braking as needed), and extend the service life of the brake pads;

[0056] The system receives feedback from pressure sensors on the actual braking pressure of each wheel to achieve closed-loop control. Each electro-hydraulic proportional control brake valve is equipped with a pressure sensor to collect the actual braking pressure of each tire in real time and feed it back to the brake-by-wire controller to achieve closed-loop control.

[0057] The hydraulic brakes are wet brakes. They employ multi-disc wet brakes, offering good braking performance, minimal heat fade, and a low failure rate. The brake-by-wire controller is connected to the vehicle controller via CAN.

[0058] The outlet of the electro-hydraulic proportional control brake valve is connected to the inlet of the hydraulic brake via a pipeline, or it is directly attached to the inlet of the hydraulic brake via a plate. Each electro-hydraulic proportional control brake valve is located near each hydraulic brake, and the brake pressure outlet is connected to the inlet of the hydraulic brake via a pipeline or directly attached to the plate, which greatly shortens the braking response time.

[0059] Among them, the braking force requirement of the brake-by-wire controller comes from the foot potentiometer or remote control signal, which can realize remote vehicle control and achieve assisted driving in combination with the intelligent driver assistance system.

[0060] Among them, the brake-by-wire controller, vehicle controller, electro-hydraulic proportional control brake valve, pressure sensor, and foot potentiometer are all explosion-proof or intrinsically safe, meeting the requirements of coal mine safety.

[0061] The beneficial effects of the above technical solution are as follows:

[0062] This invention employs an electro-hydraulic proportional control brake valve, with each hydraulic brake corresponding to an independent electro-hydraulic proportional control valve. This valve is directly integrated into / located near the inlet of each hydraulic brake, significantly shortening the hydraulic line length and solving the problem of long hydraulic lines and response times in existing technologies, particularly the "long hydraulic lines from the foot pedal valve to the wet brake," thus significantly improving braking response speed. Simultaneously, by controlling the current to regulate the output pressure, continuous and precise closed-loop regulation of braking force is achieved, avoiding the limitation of existing technologies where "braking pressure is solely determined by the pedal's mechanical travel," resulting in a substantial improvement in control accuracy and stability.

[0063] Each hydraulic brake corresponds to a set of electro-hydraulic proportional control valves, which can control different braking torques for each tire according to actual needs, so as to achieve anti-lock braking and anti-skid functions.

[0064] The braking force requirement of the brake-by-wire controller comes from a foot potentiometer (local operation) or a remote control signal (remote drive-by operation), enabling remote vehicle control and assisted driving in conjunction with an intelligent driver assistance system. Specifically, when the driver presses the brake pedal, the foot potentiometer outputs a voltage / current signal proportional to the pedal travel. The brake-by-wire controller collects this signal in real time and, based on a preset "pedal travel - braking torque requirement" mapping relationship, converts the travel signal into a corresponding braking force requirement. This mapping relationship is determined through vehicle calibration to ensure that the pedal feel and braking intensity match driving habits. The remote control terminal (such as a dispatch center or remote control terminal) generates digital control commands containing the target deceleration or target braking torque based on the vehicle's operating status and operational requirements, and sends them to the brake-by-wire controller via an onboard communication module (such as a CAN bus). After parsing the commands, the brake-by-wire controller directly uses the target deceleration or target braking torque as the braking force requirement, achieving remote vehicle control.

[0065] The brake-by-wire controller is connected to the vehicle controller via CAN bus, acquiring real-time data such as vehicle speed, motor speed, and torque, and sending actual braking data to the vehicle controller to control brake lights, warning lights, and voice alarms. Each electro-hydraulic proportional brake valve is equipped with a pressure sensor to collect the actual braking pressure of each tire in real time and feed it back to the brake-by-wire controller, achieving closed-loop control for more precise control.

[0066] Example 2, based on Example 1, further includes a hydraulic system, which comprises:

[0067] Hydraulic pump 1, accumulator charging valve 2, with the outlet of hydraulic pump 1 connected to the inlet of accumulator charging valve 2;

[0068] Accumulator 1 (3.1) and Accumulator 2 (3.2): Their inlets are connected to the outlets of the accumulator charging valve 2, respectively. The outlets of Accumulator 1 (3.1) and Accumulator 2 (3.2) are connected to the inlets of the mechanical hydraulic brake pedal valve 4 via pipelines. Accumulator 1 (3.1) supplies brake fluid to the electro-hydraulic proportional control brake valves of the left and right front wheels, respectively, and Accumulator 2 (3.2) supplies brake fluid to the electro-hydraulic proportional control brake valves of the left and right rear wheels, respectively. The outlet of the mechanical hydraulic brake pedal valve 4 is connected to the internal shuttle valve of the electro-hydraulic proportional control brake valve. The mechanical hydraulic brake pedal valve 4 is activated by the driver.

[0069] The electric trackless rubber-wheeled vehicle has four wheels: front, rear, left, and right. The four wheels correspond to four electro-hydraulic proportional control brake valves, which are respectively denoted as electro-hydraulic proportional control brake valve one 5.1, electro-hydraulic proportional control brake valve two 5.2, electro-hydraulic proportional control brake valve three 5.3, and electro-hydraulic proportional control brake valve four 5.4.

[0070] The four wheels correspond to four pressure sensors, which are respectively labeled as Pressure Sensor 1 (6.1), Pressure Sensor 2 (6.2), Pressure Sensor 3 (6.3), and Pressure Sensor 4 (6.4).

[0071] The four wheels correspond to four wet brakes, which are designated as Wet Brake 1 (7.1), Wet Brake 2 (7.2), Wet Brake 3 (7.3), and Wet Brake 4 (7.4). The wet brakes are multi-disc wet brakes, which have good braking performance, low heat fade, and low failure rate.

[0072] The hydraulic pump 1 is driven by the hydraulic pump motor 8, which is a permanent magnet synchronous motor. The control method is speed control, which can adjust the motor speed according to the real-time needs of the braking system to achieve energy saving.

[0073] A wet brake is connected to the wheel and applies braking by the friction of multiple brake pads pushed by a piston.

[0074] Accumulator 1 (3.1) and Accumulator 2 (3.2) are connected to the mechanical-hydraulic brake pedal valve 4 via pipelines. During local driving, the driver depresses the valve core of this brake valve (mechanical-hydraulic brake pedal valve 4). The mechanical-hydraulic brake pedal valve 4 is then connected via pipelines to the shuttle valve inside the electro-hydraulic proportional control brake valve, jointly providing braking pressure to the brakes and improving safety redundancy. Specifically, during local driving, the driver depresses the brake valve core of the mechanical-hydraulic brake pedal valve 4, and the braking pressure is transmitted via pipelines to the first oil inlet of the shuttle valve inside the electro-hydraulic proportional control brake valve. Simultaneously, the hydraulic pressure output from the proportional solenoid valve inside the electro-hydraulic proportional control brake valve is transmitted to the second oil inlet of the shuttle valve. The shuttle valve, acting as a high-selectivity hydraulic logic valve, automatically compares the pressures of the two inlets and selects the one with the higher pressure as the braking power source, which is then transmitted to the wet brake through the outlet. This achieves redundant switching between local braking and electronic braking, improving safety redundancy.

[0075] Accumulator 1 (3.1) and accumulator 2 (3.2) are connected to the electro-hydraulic proportional control brake valve via pipelines. The electro-hydraulic proportional control brake valve controls the hydraulic output pressure through a proportional solenoid valve, thereby controlling the magnitude of the braking force.

[0076] Each electro-hydraulic proportional control brake valve integrates a proportional solenoid valve, shuttle valve, and pressure sensor into one unit. It adopts a cartridge valve, has a compact structure, and a high degree of modularity. Pressure sensor 6.5 and pressure sensor 6.6 are respectively installed on accumulator 1 3.1 and accumulator 2 3.2.

[0077] The beneficial effects of the above technical solution are as follows:

[0078] The electro-hydraulic proportional control brake valve is electrically connected to the brake-by-wire controller via a proportional solenoid valve. The opening degree of the proportional solenoid valve is controlled by the current output of the brake-by-wire controller. The electro-hydraulic proportional control brake valve integrates a proportional solenoid valve, shuttle valve, and pressure sensor into one unit. It uses a cartridge valve, resulting in a compact structure and high degree of modularity.

[0079] Hydraulic pump 1 is connected to accumulator charging valve 2 via pipeline. Accumulator charging valve 2 is responsible for charging accumulator 1 3.1 and accumulator 2 3.2 with fluid according to the pressure required by the braking system to maintain the operation of the braking hydraulic system and ensure that the wet brake can still operate more than 5 times when the power system fails and hydraulic pump 1 does not work, thus ensuring safety. The braking system is a dual-circuit system, with accumulator 1 3.1 and accumulator 2 3.2 supplying fluid to the front and rear braking circuits respectively. When one circuit fails, the system can still provide a certain braking force, improving braking redundancy.

[0080] The pressure sensor detects the real-time braking pressure at the braking terminal and feeds it back to the brake-by-wire controller. The brake-by-wire controller repeatedly adjusts the braking force based on the feedback value in real time to achieve closed-loop control.

[0081] Combined with traditional mechanical hydraulic brake foot valves, the shuttle valve on the brake valve is controlled by electro-hydraulic proportional control, and works simultaneously with the mechanical hydraulic brake foot valve to improve safety redundancy; the curve of the correspondence between foot depth and braking force can be customized.

[0082] Example 3, based on Example 1 or 2, further includes a memory, which stores the standard drive characteristics of the motor corresponding to the current electric trackless rubber-wheeled vehicle; the standard drive characteristics of the motor are a calibration relationship of "drive motor current - standard wheel speed - standard vehicle speed - standard drive motor torque";

[0083] The brake-by-wire controller includes:

[0084] Receiver module: Used to receive vehicle speed and drive motor related parameters sent by the vehicle controller. The drive motor related parameters include: drive motor speed and drive motor torque.

[0085] Efficiency Analysis Module: Used to determine the motor torque coefficient before braking based on the current and torque of the drive motor before braking and the standard drive characteristics of the motor.

[0086] Transmission analysis module: Determines the "transmission-vehicle speed matching coefficient" before braking based on the current drive motor speed and vehicle speed before braking;

[0087] Current analysis module: used to determine the current margin coefficient before braking by combining the theoretical maximum allowable braking current corresponding to the drive motor;

[0088] Electric Braking Distribution Analysis Module: Used to determine the initial electric braking participation ratio for the current braking based on the motor torque coefficient before the current braking, the "transmission-vehicle speed matching coefficient" before the current braking, and the current margin coefficient before the current braking;

[0089] Braking Analysis Module: Used to determine the initial electric braking torque by combining braking power demand and the initial electric braking participation ratio of the current braking; and to determine the target electric braking torque and hydraulic braking torque by combining the initial electric braking torque, the motor torque coefficient before the current braking, the "transmission-vehicle speed matching coefficient" before the current braking, the standard drive characteristics of the motor, and the theoretical maximum allowable braking current corresponding to the drive motor.

[0090] The motor torque coefficient reflects the difference between the actual output capability of the drive motor under current actual operating conditions (including load, temperature, aging, etc.) and the output capability under standard calibration conditions (rated load, ideal operating conditions).

[0091] The "transmission-vehicle speed matching coefficient" reflects the degree of matching between the actual vehicle speed-speed ratio and the standard calibrated vehicle speed-speed ratio. Essentially, it assesses the efficiency and condition of the transmission system. A coefficient close to 1 indicates a good transmission system condition and high transmission efficiency; a coefficient deviating from 1 indicates slippage, wear, or load variations in the transmission system, causing a change in the correspondence between vehicle speed and motor speed. This corrects for errors caused by changes in the transmission system's condition, making braking control more closely match the vehicle's actual driving state.

[0092] (1) The standard driving characteristics of the motor were obtained through actual vehicle calibration experiments: a site where the vehicle was operating normally was selected, and under stable driving conditions with rated load, the braking current was adjusted step by step within the range of the commonly used braking current of the drive motor. The wheel speed, vehicle speed and drive motor torque corresponding to each set of braking current were collected and recorded simultaneously to form a one-to-one discrete mapping relationship ("drive motor current - standard wheel speed - standard vehicle speed - standard drive motor torque" calibration relationship) and pre-stored in the controller as the direct query basis during braking control. In the above calibration relationship, the wheel speed, vehicle speed and drive motor torque are respectively referred to as standard wheel speed, standard vehicle speed and standard drive motor torque.

[0093] (2) Current braking motor torque coefficient = current braking drive motor torque ÷ current braking drive motor current in the standard drive motor torque corresponding to the standard drive characteristics of the motor;

[0094] (3) The current "transmission-vehicle speed matching coefficient" before braking is denoted as k; ;

[0095] k is the ratio of the actual vehicle speed-speed ratio to the standard vehicle speed-speed ratio;

[0096] (4) Current margin coefficient = (theoretical maximum allowable braking current corresponding to the drive motor - current of the drive motor before braking) ÷ theoretical maximum allowable braking current corresponding to the drive motor;

[0097] (5) The initial electric braking participation ratio is determined based on the motor torque coefficient before braking, the transmission-vehicle speed matching coefficient before braking, and the current margin coefficient before braking.

[0098] A matching rule is preset: "Motor torque coefficient before braking - Transmission-vehicle speed matching coefficient before braking - Current margin coefficient before braking - Initial electric braking participation ratio". Based on the current motor torque coefficient before braking, the current transmission-vehicle speed matching coefficient before braking, the current margin coefficient and the matching rule, the initial electric braking participation ratio of the current braking is determined.

[0099] The matching rule can be as follows: the standard initial electric braking participation ratio (typical value is 0.6) under the rated load and rated drive current of the current electric trackless rubber-tired vehicle is predetermined.

[0100] The standard initial electric braking participation ratio is determined as follows: Using a brand-new vehicle, braking tests are conducted under rated load and stable driving conditions; multiple preset electric braking participation ratios are tested on actual vehicles (each ratio uses a different common electric braking current); the electric braking participation ratio that meets the vehicle's design braking performance indicators (such as braking time and deceleration) and whose electric braking-related components (drive motor, battery, etc.) are in stable working condition is determined as the standard initial electric braking participation ratio.

[0101] The motor torque coefficient, transmission-vehicle speed matching coefficient, and current margin coefficient before braking are divided into high safety level, medium safety level, and low safety level, respectively.

[0102] Motor torque coefficient: High safety range > 0.9, 0.7 ≤ Medium safety range ≤ 0.9, Low safety range < 0.7;

[0103] Transmission-vehicle speed matching coefficient: High safety gear ≥ 0.9, 0.75 ≤ Medium safety gear < 0.9, Low safety gear < 0.75;

[0104] Current margin factor: High safety level ≥ 0.7, 0.2 ≤ Medium safety level < 0.7, Low safety level < 0.2.

[0105] When all three coefficients are at the high safety level, the standard initial electric braking participation ratio is adopted; when any coefficient is at the low safety level, the initial electric braking participation ratio is set to 0; for other operating conditions, 0.5 times the standard initial electric braking participation ratio is adopted (based on historical transportation or experimental calibration).

[0106] (6) Braking power requirement is the braking torque requirement;

[0107] Initial electric braking torque = braking demand torque × initial electric braking participation ratio of the current braking;

[0108] The target electric braking torque and hydraulic braking torque are determined by combining the initial electric braking torque, motor torque coefficient, current transmission-vehicle speed matching coefficient before braking, standard motor drive characteristics, and the theoretical maximum allowable braking current of the drive motor.

[0109] Calculate the first braking torque = initial electric braking torque ÷ (current braking motor torque coefficient × current braking "transmission-vehicle speed matching coefficient");

[0110] Find the first current corresponding to the first braking torque in the standard drive characteristics of the motor (if the first braking torque does not exist directly in the standard drive characteristics of the motor, the corresponding first current is calculated by linear interpolation of two adjacent sets of calibration data), and take the minimum value between the first current and the theoretical maximum allowable braking current corresponding to the drive motor (typically 0.8 to 0.95 times the preset safety factor) and denoted as the target current.

[0111] Target braking torque = standard drive motor torque corresponding to the target current in the standard drive characteristics of the motor × motor torque coefficient before current braking × "transmission-vehicle speed matching coefficient" before current braking;

[0112] Hydraulic braking torque = braking demand torque - target braking torque.

[0113] The beneficial effects of the above technical solution are as follows:

[0114] 1. This solution is the first to propose a collaborative evaluation of vehicle braking capability using three factors: motor torque coefficient, transmission-vehicle speed matching coefficient, and current margin coefficient. The motor torque coefficient reflects the difference between the current output capability of the drive motor and its calibrated state, eliminating performance deviations caused by motor aging and temperature changes. The transmission-vehicle speed matching coefficient corrects the impact of transmission system efficiency degradation on the vehicle speed-speed correspondence in real time. The current margin coefficient dynamically monitors the risk of motor overload. The combination of these three factors enables a precise and comprehensive evaluation of vehicle braking capability, significantly improving the robustness and adaptability of braking control—something not achieved in existing technologies.

[0115] 2. This scheme divides the three coefficients into high, medium, and low safety levels and designs clear matching rules:

[0116] When all three coefficients are simultaneously at the high safety level, the standard initial electric braking ratio is used; when any coefficient is at the low safety level, the electric braking is directly shut off, forcibly switching to hydraulic braking to fundamentally avoid the risk of brake failure; in other operating conditions, a torque ratio of 0.5 times the initial torque is used, achieving an optimal balance between safety and efficiency. This tiered active safety strategy represents a technological leap from "passive torque protection" to "active torque prediction," creatively resolving the contradiction between safety and efficiency.

[0117] 3. This solution establishes a discrete mapping relationship of "drive motor current - standard wheel speed - standard vehicle speed - standard drive motor torque" through real vehicle calibration, serving as the control benchmark; and achieves closed-loop control through bidirectional conversion: considering the electric braking demand of the vehicle state, the torque "first braking torque" under standard conditions is converted back, and then the "first current" is obtained by reverse lookup; combined with the maximum allowable braking current constraint of the motor, the "target current" is obtained, and then converted back to the "target electric braking torque" under the current state. This process not only eliminates the deviation between the theoretical model and the actual working conditions, but also ensures that the motor will not be overloaded, creatively solving the two common industry problems of "inaccurate model" and "limited capacity".

[0118] 4. This solution starts with the required braking torque, first determining the proportion that electric braking can handle through multi-coefficient evaluation, and then supplementing the difference with hydraulic braking: When capacity is sufficient, an appropriate proportion of electric braking is determined, prioritizing the use of the electric motor for braking to reduce mechanical wear and impact on hydraulic braking components, while avoiding overload operation of the motor; when capacity is limited, the proportion of electric braking is automatically reduced, with hydraulic braking making up the difference, ensuring that the total braking torque meets the requirements. This dynamic allocation strategy creatively achieves synergistic optimization of motor protection (and energy recovery) and braking performance, rather than a simple priority switching.

[0119] Example 4: Based on any one of Examples 1-3, the memory also stores the thermal characteristics of the motor corresponding to the current electric trackless rubber-wheeled vehicle. The motor thermal characteristics are a calibration relationship of "drive motor current - standard temperature rise rate of the key temperature zone of the drive motor"; the relevant parameters of the drive motor also include the temperature of the key temperature zone of the drive motor.

[0120] The brake-by-wire controller also includes a thermal analysis module, which includes:

[0121] Analysis Unit 1: Determine the standard temperature rise rate of each key temperature zone corresponding to the current braking drive motor current based on the current braking drive motor current and motor thermal characteristics.

[0122] Calculation unit: used to calculate the actual temperature rise rate of each critical temperature zone before braking based on the current critical temperature zone temperature of the drive motor before braking; and to determine the temperature rise rate coefficient of each critical temperature zone by combining the standard temperature rise rate of the critical temperature zone corresponding to the current driving current before braking.

[0123] Analysis Unit 2: Used to determine the theoretical maximum allowable braking current of the drive motor based on the current critical temperature zone temperature and temperature rise rate coefficient of the drive motor before braking, and the target braking time;

[0124] When the temperature rise rate coefficient of any critical temperature zone exceeds a preset coefficient (typically 1.2), the brake-by-wire controller generates a corresponding alarm message and sends it to the vehicle controller. The vehicle controller then takes tiered response measures based on the alarm level, such as recording fault codes, alerting the driver, limiting the electric braking ratio, or forcibly switching to hydraulic braking. For example: when the temperature rise rate coefficient is slightly greater than 1.2 (Level 1 alarm), the system records a fault code and alerts the driver, while appropriately limiting the electric braking participation ratio; when the temperature rise rate coefficient further increases (e.g., greater than 1.3) (Level 2 alarm), the system significantly reduces the electric braking output and increases hydraulic braking intervention; when the temperature rise rate coefficient exceeds a higher threshold (e.g., 1.5) (Level 3 alarm), the system immediately forces a switch to hydraulic braking, triggering an audible and visual alarm to alert the driver to stop and inspect the vehicle. This achieves a smooth transition from warning to protection, ensuring driving safety while avoiding unnecessary performance loss.

[0125] Current critical temperature zone temperature rise rate coefficient = Actual temperature rise rate of the current critical temperature zone within the preset historical time before braking ÷ Standard temperature rise rate of the current critical temperature zone corresponding to the driving current before braking.

[0126] The maximum permissible temperature rise rate for the current critical temperature zone during current braking = (the safe temperature of the current critical temperature zone - the temperature at the end of the preset historical duration before current braking in the current critical temperature zone) ÷ the target braking duration.

[0127] The first temperature rise rate is obtained by multiplying the current maximum allowable temperature rise rate of the current critical temperature zone by the temperature rise rate coefficient of the current critical temperature zone. The drive motor current corresponding to the first temperature rise rate, i.e. the maximum allowable braking current of the current critical temperature zone, is obtained from the motor thermal characteristics.

[0128] The minimum value of the maximum permissible braking current in all critical temperature zones is taken as the theoretical maximum permissible braking current corresponding to the current drive motor.

[0129] The system acquires temperature data of key temperature zones of the drive motor (such as stator windings, permanent magnets, and housing) in real time through temperature sensors within a preset historical time period before braking (e.g., 5 or 10 seconds before braking). For each key temperature zone, the actual temperature rise rate of that zone before braking is obtained by dividing the temperature change within that time period (temperature at the end of that time period - temperature at the beginning of that time period) by the time span.

[0130] The target braking time (typically 3 to 5 seconds) refers to the expected duration from when the driver issues a braking command (or the system triggers braking) to when the vehicle reaches the target deceleration / target speed under the current braking conditions.

[0131] Methods for obtaining motor thermal characteristics: These can be obtained through actual vehicle calibration tests. Under the rated load, rated cooling conditions, and standard ambient temperature of the vehicle in actual operation, different levels of current are applied to the drive motor, and the temperature changes of key temperature zones such as the stator winding, permanent magnet, and housing are collected in real time. The temperature rise rate under the corresponding current is calculated to form "current-temperature rise rate" test data. Then, a continuous mapping relationship is constructed through linear interpolation or polynomial fitting methods, or a calibration table is directly generated and stored in memory. If necessary, fine-tuning is performed in combination with actual vehicle operating data under different operating conditions to ensure that the relationship is highly consistent with the actual operating conditions of the vehicle.

[0132] The beneficial effects of the above technical solution are as follows:

[0133] This invention breaks away from the traditional technical paradigm where "motor thermal protection" and "braking control" are independent. For the first time, it constructs an integrated linear control dynamic thermal management closed loop that combines "thermal state assessment, braking constraint calculation, and safety early warning response." By identifying thermal risks in advance through the temperature rise rate coefficient, it calculates the maximum allowable braking current for key components such as stator windings, permanent magnets, and housing, and takes the minimum value as a global constraint. At the same time, it deeply binds the target braking time and temperature rise rate coefficient to the calculation of the maximum allowable braking current, ensuring intelligent coordination between the motor's all-dimensional thermal safety and braking performance.

[0134] The temperature rise rate coefficient accurately quantifies the deviation of the heating intensity from the calibrated state by the relative ratio of "actual temperature rise rate / standard temperature rise rate", achieving accurate capture of thermal trends. It can not only identify high-risk conditions of "excessive temperature rise" when the temperature has not reached the limit, thus avoiding sudden overheating, but also eliminate interference from operating conditions such as current magnitude and load fluctuations. It can objectively reflect the health of the motor in different scenarios, greatly improving the reliability of thermal condition assessment.

[0135] By directly incorporating the temperature rise rate coefficient and target braking time into the calculation of the maximum allowable braking current, thermal protection becomes an intrinsic constraint of braking control, achieving the dual advantages of dynamic adaptation and precise constraint: allowing a larger current during short-term emergency braking to ensure braking performance, and automatically limiting the current to prevent overheating during long-term continuous braking. At the same time, through multi-temperature zone current minimum value constraints, it ensures that all critical parts are within the safe range, avoiding irreversible damage to the motor caused by local overheating, thus solving the problem of balancing braking performance and thermal safety.

[0136] Example 5, based on any one of Examples 1-4, further includes:

[0137] Temperature detection module: used to detect the temperature of the brake fluid in the electro-hydraulic proportional control brake valve to be input;

[0138] The control system's memory stores the current-pressure characteristics and temperature-oil viscosity relationship of the electro-hydraulic proportional control brake valve; the current-pressure characteristics of the electro-hydraulic proportional control brake valve are a calibration relationship of "oil viscosity - electro-hydraulic proportional control brake valve control current - standard output pressure - standard pressure stabilization time"; the memory also stores multiple viscosity zones for all oil viscosity divisions in the calibration relationship.

[0139] The brake-by-wire controller includes a hydraulic brake analysis module, which includes:

[0140] Historical analysis unit: used to combine the actual hydraulic braking data of the latest historical time window to determine the pressure hysteresis coefficient and pressure loss coefficient for each hydraulic braking action;

[0141] Temperature Influence Analysis Unit: Obtain the latest M (e.g., 2-5) brake sequence numbers from historical braking data that belong to the same viscosity zone as the current braking oil viscosity (all denoted as target brake sequence numbers), and determine the current viscosity-pressure hysteresis influence parameters and viscosity-pressure loss influence parameters based on the target viscosity corresponding to the target brake sequence number;

[0142] Prediction Unit: Used to determine the current predicted pressure hysteresis coefficient and the current predicted pressure loss coefficient by combining the current brake fluid temperature before hydraulic braking and the current-pressure characteristics of the electro-hydraulic proportional control brake valve, the viscous pressure hysteresis effect parameters and the viscous pressure loss effect parameters.

[0143] Current analysis unit: used to determine the target control current by combining the target hydraulic braking pressure, the current predicted pressure loss coefficient, and the current-pressure characteristics of the electro-hydraulic proportional control brake valve.

[0144] According to the braking power demand, the brake-by-wire controller decomposes the total braking force into hydraulic braking torque and motor braking torque; sends the target control current to each electro-hydraulic proportional control brake valve to adjust the braking pressure of each hydraulic brake, and at the same time sends the braking torque command to the motor controller to drive the motor to perform electric braking; The target hydraulic braking pressure is defined as: the theoretical output pressure of the hydraulic branch that matches the current hydraulic braking torque; it can be determined based on vehicle braking technology. Another method for obtaining the target hydraulic braking pressure is as follows: Based on the allocated hydraulic braking torque, the hydraulic braking torque-hydraulic pressure calibration mapping relationship pre-stored in the memory is retrieved, and the target hydraulic braking pressure is obtained by table lookup or linear interpolation. The hydraulic braking torque-hydraulic pressure calibration mapping relationship is an inherent mechanical characteristic of the hydraulic brake itself. The acquisition method is as follows: The hydraulic braking system assembly (including the hydraulic brake, which can be a wet brake in this invention) is installed on the braking test bench. The hydraulic source outputs a stepped steady-state oil pressure to the hydraulic brake in stages. After the oil pressure and output braking torque stabilize, multiple sets of paired discrete data of hydraulic pressure and hydraulic braking torque are collected simultaneously. After covering the entire working oil pressure range of the hydraulic brake, the discrete data are linearly fitted piecewise to generate a continuous calibration mapping relationship that can be interpolated and queried, and pre-stored in the memory of the linear control brake controller.

[0145] Early warning unit: An early warning is issued when the current predicted pressure hysteresis coefficient is greater than the preset pressure hysteresis coefficient (not reaching an abnormal state affecting braking), reminding the user that maintenance and adjustment are needed; the target control current is determined to correspond to the pressure stabilization time in the current-pressure characteristics, then multiplied by the current predicted pressure loss coefficient to obtain the compensation time, and then the compensation time is added to obtain the predicted pressure stabilization time (the pressure stabilization time corresponding to the current-pressure characteristics + the compensation time). An early warning is also issued when the ratio of the predicted pressure stabilization time to the target braking pressure stabilization time (target braking pressure stabilization time ÷ predicted pressure stabilization time) is less than a preset value (range 0.8–0.93); The pressure stabilization time is the total time consumed after applying a fixed control current to the electro-hydraulic proportional brake valve, from the initial rise of the hydraulic output pressure until the pressure fluctuation coefficient shrinks to an allowable range (e.g., within a continuous sampling window, the ratio of the difference between the maximum and minimum pressure values ​​within the window to the average value within the window is the pressure fluctuation coefficient under steady state, with an allowable range of 3%), and remains stable.

[0146] The pressure stabilization time corresponding to the target control current in the current pressure characteristic is determined, and then multiplied by the current predicted pressure loss coefficient to obtain the predicted pressure stabilization time. When the ratio of the predicted pressure stabilization time to the target braking pressure stabilization time is less than a preset value (the value range is 0.8 to 0.93), an early warning is also issued.

[0147] (1) Temperature-oil viscosity relationship acquisition: On the test bench, the brake fluid of the specified brand of the vehicle is heated or cooled to the vehicle's usual working oil temperature (such as -10℃ to 60℃). The kinematic viscosity or dynamic viscosity at each oil temperature is directly measured by a viscometer to form discrete data of "oil temperature-oil viscosity". Then, a continuous mapping relationship is obtained by fitting and solidified in the memory.

[0148] Acquisition of current-pressure characteristics of electro-hydraulic proportional control brake valve: On the test bench, the hydraulic circuit must be arranged strictly according to the routing, diameter, length, and valve installation position of the actual vehicle's brake lines to ensure that the oil flow resistance and heat dissipation conditions are consistent with the actual vehicle. Simultaneously, an oil temperature control unit consistent with the actual vehicle's heat dissipation / heating logic is installed in the circuit to precisely adjust and stabilize the brake fluid temperature within the vehicle's commonly used operating temperature range (such as -10℃, 0℃, 20℃, 40℃, 60℃, etc.). After the oil temperature stabilizes and becomes uniform throughout the circuit, the vehicle's commonly used control current is applied sequentially, and the output braking pressure and pressure stabilization time corresponding to each current are recorded. The test is repeated for different commonly used oil temperature conditions, ultimately forming a calibration table of "oil viscosity or oil viscosity range - commonly used control current - standard output pressure - standard pressure stabilization time" for the controller to use in real time. The relevant parameters determined by calibration are recorded as standard parameters.

[0149] The stabilization time refers to the time required from the application of the control current to the electro-hydraulic proportional control brake valve until the output brake pressure fluctuation is less than the preset range (typically ±2% to ±5%) corresponding to the control current and remains stable. Under ideal operating conditions, this is the ideal stabilization time to achieve the driver's desired target hydraulic brake pressure. "The preset pressure hysteresis coefficient can be calibrated on a real vehicle, taking the 90th percentile of the hysteresis coefficient distribution under normal operating conditions."

[0150] One rule for dividing the viscosity zone is as follows (the viscosity zone threshold can be flexibly adjusted based on the actual vehicle calibration results):

[0151]

[0152] (2) The latest historical time window refers to the shortest effective time interval for the brake-by-wire controller to analyze hydraulic braking data (usually 500ms to 2s (can be adjusted according to the actual vehicle calibration)).

[0153] The pressure hysteresis coefficient of the current hydraulic braking = (actual pressure stabilization time of the current hydraulic braking - standard pressure stabilization time corresponding to the current hydraulic braking) ÷ standard pressure stabilization time corresponding to the current hydraulic braking;

[0154] The standard pressure stabilization time corresponding to the current hydraulic braking is: the standard pressure stabilization time corresponding to the current of the current hydraulic braking in the current-pressure characteristic.

[0155] Pressure loss coefficient for the current hydraulic braking operation = (Standard output pressure for the current hydraulic braking operation - Actual output pressure for the current hydraulic braking operation) ÷ Standard output pressure for the current hydraulic braking operation

[0156] The standard output pressure corresponding to the current hydraulic braking is: the standard output pressure corresponding to the current of the current hydraulic braking in the current-pressure characteristic.

[0157] (3) The braking sequence number is ordered according to the braking time (the braking sequence number of the later braking time is greater than the braking sequence number of the earlier braking time); "The braking sequence number is a globally incrementing unique identifier";

[0158] Take the viscosity of the target braking sequence number (denoted as the target viscosity). The viscosity-pressure hysteresis effect parameter corresponding to the adjacent target viscosity is: the difference between the pressure hysteresis coefficient corresponding to the larger viscosity and the pressure hysteresis coefficient corresponding to the smaller viscosity of the adjacent target viscosity ÷ the difference between the larger viscosity and the smaller viscosity of the adjacent target viscosity.

[0159] The viscosity-pressure loss effect parameter corresponding to adjacent target viscosities is: the difference between the pressure loss coefficient corresponding to the higher viscosity and the pressure loss coefficient corresponding to the lower viscosity of adjacent target viscosities ÷ the difference between the higher viscosity and the lower viscosity of adjacent target viscosities;

[0160] The maximum value of the viscous-pressure hysteresis effect parameter of all adjacent viscosities is taken as the target viscous-pressure hysteresis effect parameter, and the maximum value of the viscous-pressure loss effect parameter of all adjacent viscosities is taken as the target viscous-pressure loss effect parameter.

[0161] Current predicted pressure hysteresis coefficient = latest target braking sequence pressure hysteresis coefficient + target viscosity difference × target viscosity-pressure hysteresis influence parameter;

[0162] Current predicted pressure loss coefficient = pressure loss coefficient of the latest target braking sequence number + target viscosity difference × target viscosity-pressure loss influence parameter;

[0163] The target viscosity difference is: the viscosity at the current hydraulic braking temperature in the "temperature-oil viscosity relationship" - the viscosity of the latest target braking sequence number;

[0164] Before system initialization or the first braking, a calibration can be performed manually within each viscosity range (or factory-stored calibration data can be read) to ensure that there is at least one historical braking data record for each viscosity range. Alternatively, historical braking data for each viscosity range can be calibrated periodically during vehicle use. (4) Used to determine the target control current by combining the target hydraulic braking pressure, the current predicted pressure loss coefficient, and the current-pressure characteristics of the electro-hydraulic proportional control brake valve, specifically: First, calculate the corrected target pressure based on the target hydraulic braking pressure and the current predicted pressure loss coefficient. Then, in the current-pressure characteristic of the electro-hydraulic proportional control brake valve (the calibration table for "oil viscosity or oil viscosity range - commonly used control current - standard output pressure - standard pressure stabilization time"), obtain the target control current by looking up the table or by linear interpolation based on the current pre-braking oil viscosity and the corrected target pressure.

[0165] Corrected target pressure = target hydraulic braking pressure ÷ (1 − current predicted pressure loss coefficient).

[0166] Specifically: The first step is to filter the range: In the calibration table of "oil viscosity or oil viscosity range - common control current - standard output pressure - standard pressure stabilization time", match the unique oil viscosity or oil viscosity range to which the current pre-braking oil viscosity belongs, and the corresponding set of sub-calibration data (correspondence between "common control current - standard output pressure - standard pressure stabilization time"). The second step is to retrieve the matching pressure: Within the viscosity range sub-calibration data obtained in the first step, the corrected target pressure is used as the retrieval benchmark value. If the corrected target pressure is exactly equal to a certain standard output pressure in the sub-calibration data, the common control current corresponding to that line is directly read as the initial target current. If the corrected target pressure falls between two adjacent standard output pressures, then perform linear interpolation on the common control currents corresponding to the two standard output pressures to calculate the interpolated preliminary target current. Finally, the initial target current is subjected to boundary limiting: the value is constrained within the upper and lower limits of the rated operating current of the electro-hydraulic proportional control brake valve, and the final output target control current is obtained after limiting.

[0167] The beneficial effects of the above technical solution are as follows:

[0168] By predicting the pressure loss coefficient during braking, the target hydraulic braking pressure is compensated and corrected. Then, the target control current is obtained by combining the current-pressure characteristics of the electro-hydraulic proportional control brake valve. This effectively offsets the pressure attenuation caused by factors such as brake fluid viscosity changes, pipeline resistance, and leakage, making the actual output braking force more accurately match the driver's intention and significantly improving the control accuracy and response consistency of the brake-by-wire system.

[0169] Based on historical braking data, viscosity-pressure influence parameters can accurately predict the pressure hysteresis coefficient at different viscosities. When the predicted value exceeds a preset threshold, the system issues an early warning, indicating a slight degradation in braking response performance. This allows users to perform maintenance before a fault affects braking safety, realizing a shift from "post-fault repair" to "performance degradation early warning," thus improving the safety and reliability of vehicle operation.

[0170] The solution calculates brake fluid viscosity in real time using the temperature-oil viscosity relationship and, combined with preset hysteresis coefficients and graded early warning strategies for multiple viscosity ranges, can dynamically adapt to operating conditions across the entire temperature range, from extremely cold to high temperatures. Even when viscosity increases significantly due to extreme low temperatures, the system maintains stable control performance and reasonable early warning logic. The solution employs a dual-dimensional early warning mechanism of "pressure hysteresis coefficient exceeding limits" and "predicted pressure stabilization time ratio being too small," focusing on both braking response speed and pressure build-up time, enabling more comprehensive and earlier identification of potential risks in the braking system.

[0171] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A wire-controlled braking system for an electric trackless rubber-tired vehicle, characterized in that: include: Electro-hydraulic proportional control brake valve: configured to adjust the output braking pressure according to the input control current value; Multiple hydraulic brakes: Each hydraulic brake is set up one-to-one with each wheel of the electric trackless rubber-tired vehicle, and each hydraulic brake is set up with a set of electro-hydraulic proportional control brake valves. The outlet of the electro-hydraulic proportional control brake valves is connected to the inlet of the hydraulic brake. Pressure sensor: Installed on each electro-hydraulic proportional control brake valve, used to collect the actual braking pressure of the corresponding hydraulic brake; The wire-controlled brake controller is communicatively connected to the electro-hydraulic proportional control brake valve and the pressure sensor, and is configured as follows: Based on the braking power requirements, the braking force is decomposed into hydraulic braking force and electric braking force; control current is sent to each electro-hydraulic proportional control brake valve to control the braking pressure of each hydraulic brake, and braking torque information is sent to the motor controller to control the drive motor to implement electric braking; It receives the actual braking pressure of each wheel from the pressure sensor to achieve closed-loop control. The electric trackless rubber-tired vehicle's line-controlled braking system also includes: Temperature detection module: used to detect the temperature of the brake fluid in the electro-hydraulic proportional control brake valve to be input; The control system's memory stores the current-pressure characteristics and temperature-oil viscosity relationship of the electro-hydraulic proportional control brake valve; the current-pressure characteristics of the electro-hydraulic proportional control brake valve are a calibration relationship of "oil viscosity - electro-hydraulic proportional control brake valve control current - standard output pressure - standard pressure stabilization time"; the memory also stores multiple viscosity zones for all oil viscosity divisions in the calibration relationship. The brake-by-wire controller includes a hydraulic brake analysis module, which includes: Historical analysis unit: used to combine the actual hydraulic braking data of the latest historical time window to determine the pressure hysteresis coefficient and pressure loss coefficient for each hydraulic braking action; Temperature Influence Analysis Unit: Obtain the latest M brake numbers from historical braking data that belong to the same viscosity zone as the current pre-braking oil viscosity, and determine the current viscosity-pressure hysteresis influence parameters and viscosity-pressure loss influence parameters based on the target viscosity corresponding to the target brake number; Prediction Unit: Used to determine the current predicted pressure hysteresis coefficient and the current predicted pressure loss coefficient by combining the current brake fluid temperature before hydraulic braking and the current-pressure characteristics of the electro-hydraulic proportional control brake valve, the viscous pressure hysteresis effect parameters and the viscous pressure loss effect parameters. Current analysis unit: used to determine the target control current by combining the target hydraulic braking pressure, the current predicted pressure loss coefficient, and the current-pressure characteristics of the electro-hydraulic proportional control brake valve.

2. The electric trackless rubber-tired vehicle line control braking system according to claim 1, characterized in that: The hydraulic brake is a wet brake.

3. The electric trackless rubber-tired vehicle line control braking system according to claim 1, characterized in that: The brake-by-wire controller is connected to the vehicle controller via CAN.

4. The electric trackless rubber-tired vehicle line control braking system according to claim 1, characterized in that: The outlet of the electro-hydraulic proportional control brake valve is connected to the inlet of the hydraulic brake via a pipeline, or it can be directly attached to the inlet of the hydraulic brake via a plate.

5. The electric trackless rubber-tired vehicle line control braking system according to claim 1, characterized in that: The braking force requirement of the brake-by-wire controller comes from a foot potentiometer or a remote control signal.

6. The electric trackless rubber-tired vehicle line control braking system according to claim 1, characterized in that: It also includes a hydraulic system, which comprises: Hydraulic pump (1) and accumulator charging valve (2), wherein the outlet of the hydraulic pump (1) is connected to the inlet of the accumulator charging valve (2); Accumulator 1 (3.1) and Accumulator 2 (3.2): The inlets of Accumulator 1 (3.1) and Accumulator 2 (3.2) are connected to the outlets of the accumulator filling valve (2), respectively. The outlets of Accumulator 1 (3.1) and Accumulator 2 (3.2) are connected to the inlets of the mechanical hydraulic brake pedal valve (4) through pipelines. Accumulator 1 (3.1) provides brake fluid to the electro-hydraulic proportional control brake valves of the left front wheel and the right front wheel, respectively. Accumulator 2 (3.2) provides brake fluid to the electro-hydraulic proportional control brake valves of the left rear wheel and the right rear wheel, respectively. The outlet of the mechanical hydraulic brake pedal valve (4) is connected to the internal shuttle valve of the electro-hydraulic proportional control brake valve. The mechanical hydraulic brake pedal valve (4) is started by the driver.

7. The electric trackless rubber-tired vehicle line control braking system according to claim 1, characterized in that: Based on the braking power requirements and combined with the current vehicle speed and relevant parameters of the drive motor, the brake-by-wire controller decomposes the braking force into hydraulic braking force and electric motor braking force.

8. The electric trackless rubber-tired vehicle line control braking system according to claim 7, characterized in that: It also includes a memory that stores the standard drive characteristics of the motor corresponding to the current electric trackless rubber-wheeled vehicle; the standard drive characteristics of the motor are a calibration relationship of "drive motor current - standard wheel speed - standard vehicle speed - standard drive motor torque"; The brake-by-wire controller includes: Receiver module: Used to receive vehicle speed and drive motor related parameters sent by the vehicle controller. The drive motor related parameters include: drive motor speed and drive motor torque. Efficiency Analysis Module: Used to determine the motor torque coefficient before braking based on the current current and torque of the drive motor before braking and the standard drive characteristics of the motor. Transmission analysis module: Determines the "transmission-vehicle speed matching coefficient" before braking based on the current drive motor speed and vehicle speed before braking; Current analysis module: used to determine the current margin coefficient before braking by combining the theoretical maximum allowable braking current corresponding to the drive motor; Electric Braking Distribution Analysis Module: Used to determine the initial electric braking participation ratio of the current braking based on the motor torque coefficient before the current braking, the "transmission-vehicle speed matching coefficient" before the current braking, and the current margin coefficient before the current braking; Braking Analysis Module: Used to determine the initial electric braking torque by combining braking power demand and the initial electric braking participation ratio of the current braking; and to determine the target electric braking torque and hydraulic braking torque by combining the initial electric braking torque, the motor torque coefficient before the current braking, the "transmission-vehicle speed matching coefficient" before the current braking, the standard drive characteristics of the motor, and the theoretical maximum allowable braking current corresponding to the drive motor.

9. A wire-controlled braking system for an electric trackless rubber-tired vehicle according to claim 1 or 8, characterized in that: The braking system's memory also stores the thermal characteristics of the motor corresponding to the current electric trackless rubber-wheeled vehicle. The motor's thermal characteristics are a calibration relationship of "drive motor current - standard temperature rise rate of the key temperature zone of the drive motor". The relevant parameters of the drive motor also include the temperature of the key temperature zone of the drive motor; The brake-by-wire controller also includes a thermal analysis module, which includes: Analysis Unit 1: Determine the standard temperature rise rate of each key temperature zone corresponding to the current braking drive motor current based on the current braking drive motor current and motor thermal characteristics. Calculation unit: used to calculate the actual temperature rise rate of each critical temperature zone before braking based on the current critical temperature zone temperature of the drive motor before braking; and to determine the temperature rise rate coefficient of each critical temperature zone by combining the standard temperature rise rate of the critical temperature zone corresponding to the current driving current before braking. Analysis Unit 2: Used to determine the theoretical maximum allowable braking current of the drive motor based on the current critical temperature zone temperature and temperature rise rate coefficient of the drive motor before braking, and the target braking time; When the temperature rise rate coefficient of any critical temperature zone exceeds the preset coefficient, the brake-by-wire controller generates a corresponding alarm message and sends it to the vehicle controller.

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