Electronic mechanical braking device of mining dump truck and braking torque distribution method

Abstract

The invention discloses a mining dump truck electronic mechanical braking device and a braking torque distribution method. The mining dump truck electronic mechanical braking device comprises a chassis controller, a power module, an electronic mechanical braking device body and a sensor module. The chassis controller, the electronic mechanical braking device and the sensor module are all electrically connected with the power module, and the electronic mechanical braking device and the sensor module are both electrically connected with the chassis controller. The sensor module collects dumper driving information and transmits the dumper driving information to the chassis controller, the chassis controller is used for judging a braking mode according to the information transmitted by the sensor module, distributing braking torque and transmitting the braking torque to the electronic mechanical braking device, and the electronic mechanical braking device completes the braking process according to a received instruction. Through closed-loop control over the electronic mechanical braking device, it is ensured that quick response can be achieved in different braking modes, and the braking action can be stably and reliably completed.

Description

An electromechanical braking device and braking torque distribution method for mining dump trucks Technical Field

[0001] This invention relates to an electromechanical braking device, specifically to an electromechanical braking device for a mining dump truck and a method for distributing braking torque. Background Technology

[0002] Traditional pneumatic and hydraulic braking systems suffer from drawbacks such as system complexity, high maintenance costs, susceptibility to temperature variations, and slow response. Electromechanical braking systems, on the other hand, utilize electrical signal control, resulting in faster response times, higher integration, and lower maintenance costs. Currently, some driverless mining trucks have achieved cockpitless operation and are in use; in the future, cockpitless driverless mining trucks will inevitably see large-scale deployment. Electromechanical braking systems align with this development trend.

[0003] With the development of related technologies, the cost of modules such as high-power motors, high-voltage battery packs, and commercial vehicle controllers suitable for electromechanical braking systems of heavy vehicles has decreased, providing conditions for the research of electromechanical braking systems for mining dump trucks. For the upcoming smart mines, the development of electromechanical braking systems for mining dump trucks has a very broad research prospect.

[0004] In recent years, significant progress has been made in the research of electromechanical braking devices and braking torque distribution strategies for mining dump trucks, resulting in substantial improvements in load-bearing capacity, response characteristics, and control coordination. However, significant shortcomings remain for the harsh working conditions of mines: In terms of electromechanical braking devices, to meet the demands of heavy-load, high-torque output, the system generally employs multi-stage reduction and force amplification mechanisms, leading to excessively long transmission chains, large transmission chain errors, and reduced braking force transmission accuracy and response speed. Simultaneously, multi-stage transmission results in a large number of parts, complex structural processes, high precision requirements for key transmission pairs, and difficulties in assembly and positioning.

[0005] Regarding braking torque distribution strategies, the current braking torque distribution strategies used in mining dump trucks mostly adopt fixed ratios or simple feedback adjustment methods, which have poor adaptability to extreme working conditions. At the same time, these strategies rely on a single control unit and braking circuit, have low fault tolerance, and are prone to loss of control of braking torque distribution or even braking failure when the braking device fails. They lack necessary safety redundancy, cannot guarantee braking performance and stability, and pose significant safety risks. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides an electromechanical braking device and braking torque distribution method for mining dump trucks. It can measure the driving status of dump trucks in real time under harsh mining operating conditions, and judge, switch, and enter specific braking modes accordingly, ultimately achieving stable and rapid braking in each braking mode.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an electromechanical braking device for a mining dump truck, comprising an electromechanical braking execution unit, the electromechanical braking execution unit including a brake motor, a brake motor controller, a disc brake, brake pads, and a transmission mechanism; the brake motor including a motor rotor and a motor stator; the transmission mechanism including planetary gears, a ball screw, and a lever mechanism; the planetary gears including a sun gear, a planet carrier, and planetary gears; the ball screw including a lead screw, rollers, and a roller nut; the lever mechanism including a lever and an outer brake caliper; the motor stator is disposed on the inner wall of the motor housing, and one end of the output shaft of the motor rotor is connected to the motor housing via a bearing. The other end is connected to the sun gear via a key. The external teeth of the sun gear mesh with several planet gears, and the planet gears mesh with the internal teeth of the gear ring. The gear ring is set on the inner wall of the motor housing. One end of the planet carrier is connected to the planet gears, and the other end is connected to one end of the lead screw. The outer wall of the lead screw is connected to the roller nut via rollers. The outer end of the roller nut passes through the motor housing and is connected to a brake pad. The circumferential outer wall of the roller nut is hinged to one end of the lever. The other end of the lever passes through the motor housing and is hinged to one end of the outer brake caliper. One end of the outer brake caliper is connected to another brake pad. The disc brake is set between the two brake pads. The brake motor controller is electrically connected to the brake motor.

[0008] Furthermore, a lever shaft is provided on the motor housing at the point where the lever protrudes, and the lever is hinged to the lever shaft.

[0009] Furthermore, two levers are symmetrically arranged on the outer circumferential wall of the roller nut.

[0010] A method for distributing electromechanical braking torque in a mining dump truck includes a chassis controller, a power module, an electromechanical braking device, and a sensor module. The chassis controller, electromechanical braking device, and sensor module are all electrically connected to the power module, and the electromechanical braking device and sensor module are also electrically connected to the chassis controller. The torque distribution to each wheel under normal braking mode is as follows: S1. The base braking torque is calculated as follows: The normal forces on the front and rear wheels of the dump truck on horizontal roads and sloping roads are as follows: Horizontal road: ; Sloping road: In the formula: For the normal force of the front left wheel, For the normal force of the front right wheel, For the normal force of the rear left wheel, The normal force is that of the rear right wheel; This is the distance from the center of gravity to the front axle. ρ is the distance from the center of mass to the rear axle, m is the total mass of the vehicle, and g is the acceleration due to gravity. The height of the center of mass above the ground. The slope of the ramp. The acceleration of the dump truck is given; further, the maximum ground adhesion and maximum braking torque of the wheels can be obtained: ; In the formula: This represents the maximum ground adhesion of the wheels. The maximum braking torque of the wheel, The coefficient of friction between the wheels and the road surface. This is the actual normal force on the wheel. Let the wheel rolling radius be denoted as ; considering both anti-lock braking and rapid braking scenarios, a safety factor is defined, and the braking torque of a single wheel is taken as : In the formula: This represents the actual braking torque of the wheels; ultimately, the reference braking torque of the dump truck is obtained: In the formula: S2 is the reference braking torque; S2, calculate the additional yaw moment: use a linear two-degree-of-freedom model to perform dynamic modeling of the dump truck, and the modeling results are as follows: In the formula: This is the yaw acceleration. The angular velocity of the center of mass deflection; The yaw rate is angular velocity. The sideslip angle is the angle of the center of mass. For front axle lateral stiffness, For rear axle lateral stiffness, Let v be the moment of inertia of the dump truck about the z-axis; v is the speed of the dump truck. The front wheel steering angle; the yaw rate of the dump truck under stable driving conditions. and centroid side slip angle All are constants, therefore the yaw acceleration and the angular velocity of the center of mass deflection All are 0, =0、 Substituting 0 into the dump truck dynamics model, we get: ; with yaw rate and centroid side slip angle Solving this system of equations for the unknowns yields: The two formulas above represent the ideal yaw rate for maintaining stable driving of a dump truck. And the ideal centroid side slip angle ,in For the wheelbase of the dump truck, then the complex constants in the formula are... Defined separately as the stability coefficient K of the dump truck, the ideal yaw rate can ultimately be obtained. And the ideal centroid side slip angle They are respectively: The upper-level controller uses stability as its control objective, and the two parameters describing stability are yaw rate. and centroid side slip angle Therefore, the control torque is first calculated for these two control objectives: yaw rate braking torque: ;in, , , In the formula: The braking torque is the yaw rate. For the ideal yaw acceleration, The front wheel angular acceleration, This represents the relative weighting coefficient between the yaw rate error and the change in error. To achieve a yaw rate gain, The yaw rate is the power coefficient, and sgn is the sign function; the braking torque at the center of mass sideslip angle is: ;in, , , In the formula: The braking torque is the sideslip angle of the center of gravity. For the ideal centroid sideslip angular velocity, The sideslip angular acceleration of the center of mass. This represents the relative weighting coefficient between the centroid sideslip angle error and the error variation. To achieve the gain as the centroid sideslip angle approaches, This represents the power coefficient of the sideslip angle; the actual yaw rate and the actual sideslip angle deviate from the ideal value in opposite directions, and the weighting formulas for their deviations are as follows: In the formula: These are the weighting coefficients; The threshold parameter is determined by the road surface adhesion coefficient. Decision; using weighting coefficients yaw rate braking torque and the braking torque of the center of gravity sideslip angle Combined into a total additional yaw moment : S3, Constraints on Reference Braking Torque and Additional Yaw Moment: To balance braking speed and stability, the reference braking torque and additional yaw moment need to be superimposed and distributed to each wheel. Therefore, the "braking torque constraint relationship" between the target braking torque, reference braking torque, and additional yaw moment of each wheel is as follows: In the formula: For the target braking torque of the front left wheel, The target braking torque for the front right wheel, For the target braking torque of the rear left wheel, The target braking torque for the rear right wheel; The distance between the front and rear wheels of the dump truck; under normal braking mode, the lower-level controller optimizes for smoothness: following the definition of variance in mathematics, the objective function is defined as follows: ;in, In the formula: The target braking torque for the wheels; objective function When the minimum value is taken, the difference in actual braking torque between each wheel is the smallest; the actual braking torque of each wheel calculated at this point is the target braking torque. Therefore, , Substitution By taking the partial derivative, the target braking torque can be obtained as: Then , Substituting the braking torque constraint relationship, we can obtain , Each brake motor controller achieves the above braking torque result by controlling its corresponding electromechanical brake actuator. If the clamping force is online, braking continues until the braking target is achieved; if the clamping force is offline, it enters the redundant braking mode.

[0011] A method for distributing electromechanical braking torque in a mining dump truck, wherein the torque distribution of each wheel under redundant braking mode is as follows: In redundant braking mode, the lower-level controller optimizes the road surface adhesion utilization rate as the objective; based on the "friction ellipse theory", the objective function is defined as follows: In the formula: The objective function is... This represents the actual longitudinal force on the wheel. The actual longitudinal force of the wheel; objective function The distributed torque at its minimum value is the target braking torque; as mentioned earlier. The following relationship exists between them: ;Will , Substitution By taking the partial derivative, the target braking torque can be obtained as: Then , Substituting the braking torque constraint relationship, we can obtain , Each brake motor controller achieves the above braking torque result by controlling its corresponding electromechanical brake actuator, and continues braking until the speed is reduced to 0.

[0012] Furthermore, when the dump truck has six wheels, the distance and working conditions of the two rear wheels on the same side are similar. Each of the two sets of rear wheels on the same side is equivalent to a single rear wheel, and the axis of symmetry of the two rear axles is taken as the equivalent rear axle. The equivalent six-wheel dump truck is simplified to a four-wheel dump truck. The normal force and longitudinal force of a single rear wheel are equal to the sum of the normal force and longitudinal force of the two rear wheels on the same side before the equivalent designation; Conventional braking mode: , It is the target braking torque for a single rear wheel, which is ultimately divided equally when applied to the two sets of rear wheels on the same side. The final result of the braking torque distribution to the six wheels is as follows: ; In the formula: For the target braking torque of the front left wheel, The target braking torque for the front right wheel, For the target braking torque of the left wheel, For the target braking torque of the right wheel, For the target braking torque of the rear left wheel, The target braking torque for the rear right wheel; As the reference braking torque, To add yaw moment, The radius of the wheel's rolling motion. This refers to the front and rear wheel track of the dump truck. Front wheel steering angle; Redundant braking mode: , It is the target braking torque for a single rear wheel, which is ultimately divided equally when applied to the two sets of rear wheels on the same side. The final result of the braking torque distribution to the six wheels is as follows: ; In the formula: For the target braking torque of the front left wheel, The target braking torque for the front right wheel, For the target braking torque of the left wheel, For the target braking torque of the right wheel, For the target braking torque of the rear left wheel, The target braking torque for the rear right wheel; For the front left wheel road adhesion coefficient, For the road surface adhesion coefficient of the front right wheel, For the rear left wheel road surface adhesion coefficient, The coefficient of friction for the rear right wheel; The actual normal force of the front left wheel, The actual normal force of the front right wheel, For the actual normal force of the rear left wheel, This represents the actual normal force on the rear right wheel; As the reference braking torque, To add yaw moment, The radius of the wheel's rolling motion. This refers to the front and rear wheel track of the dump truck. This refers to the steering angle of the front wheels.

[0013] Furthermore, the sensor module includes a wheel speed sensor, a steering angle sensor, a clamping force sensor, a camera, a lidar, a millimeter-wave radar, an inertial navigator, and an inclinometer; the wheel speed sensor and steering angle sensor are located at the wheels of the dump truck, the clamping force sensor is located at the disc brake, the camera, lidar, and millimeter-wave radar are located at the front of the dump truck, and the inertial navigator and inclinometer are located in the middle of the dump truck.

[0014] Furthermore, the power module includes a 24V low-voltage power supply and a 700V high-voltage power supply. The chassis controller, the brake motor controllers of each wheel, and the sensor module are electrically connected to the 24V low-voltage power supply; the brake motors of each wheel are electrically connected to the 700V high-voltage power supply.

[0015] Compared with the prior art, the present invention, in the field of electromechanical braking device for mining dump trucks, adopts a single-stage planetary gear reducer for speed reduction and torque amplification, and converts rotary motion into linear motion through a ball screw, which greatly simplifies the mechanical structure of the electromechanical braking device and avoids problems such as response error and assembly difficulties that may be caused by excessively long transmission chains to a certain extent; at the same time, it adopts double-sided synchronous braking of disc brakes to improve braking effect. Regarding the method of distributing braking torque for mining dump trucks, comprehensive data collection of dump truck driving information can be achieved through multi-sensor fusion. Two braking modes, conventional and redundant, are defined based on the dump truck's braking conditions. The conventional braking mode uses a comparison between the dump truck's position, speed, and the calculated expected deceleration and ideal deceleration as the entry criterion. The redundant braking mode uses the online status of the clamping force signal as the entry criterion, clarifying the braking mode entry standards and improving braking mode switching efficiency. A dual-layer controller is used to calculate and distribute braking torque. The upper-layer controller uniformly calculates the baseline braking torque and additional yaw torque, while the lower-layer controller calculates the torque distribution results according to the specific mode, balancing braking stability and speed, thereby improving braking efficiency. Attached Figure Description

[0016] Figure 1 is a structural block diagram of the present invention; Figure 2 is a schematic diagram of the overall structure of the present invention; Figure 3 is a schematic diagram of the electromechanical braking device of the present invention; Figure 4 is a cross-sectional view of the electromechanical braking device of the present invention; Figure 5 is a flowchart of the braking condition switching and braking torque distribution of the present invention; In the figures: 1, chassis controller; 101, main controller; 102, auxiliary controller; 2, power module; 201, 24V low-voltage power supply; 202, 700V high-voltage power supply; 3, electromechanical braking device; 301, brake motor; 3011, motor rotor; 3012, motor stator; 302, brake motor controller; 303, disc brake; 304, brake pad; 310, electronic mechanism. Mechanical braking actuator; 320, transmission mechanism; 321, planetary gear; 3211, sun gear; 3212, planetary carrier; 3213, planetary gear; 322, roller screw; 3221, screw; 3222, roller; 3223, roller nut; 323, lever mechanism; 3231, lever push shaft; 3232, lever; 3233, lever shaft; 3234, rotating pin; 3235, outer brake caliper; 4. Sensor module; 401, wheel speed sensor; 402, angle sensor; 403, clamping force sensor; 404, camera; 405, lidar; 406, millimeter-wave radar; 407, inertial navigator; 408, inclinometer. Detailed Implementation

[0017] The invention will now be further described with reference to the accompanying drawings.

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] As shown in Figures 2 to 4, the present invention provides an electromechanical braking device for a mining dump truck. The electromechanical braking device 3 includes an electromechanical braking execution unit 310, which includes a brake motor 301, a brake motor controller 302, a disc brake 303, a brake pad 304, and a transmission mechanism 320.

[0020] The brake motor 301 includes a motor rotor 3011 and a motor stator 3012; the transmission mechanism 320 includes a planetary gear 321, a roller screw 322, and a lever mechanism 323; the planetary gear 321 includes a sun gear 3211, a planet carrier 3212, and planet gears 3213; the roller screw 322 includes a screw 3221, rollers 3222, and roller nuts 3223; the lever mechanism 323 includes a lever push shaft 3231, a lever 3232, a lever shaft 3233, a rotating pin 3234, and an outer brake caliper 3235.

[0021] The motor stator 3012 is mounted on the inner wall of the motor housing. One end of the output shaft of the motor rotor 3011 is connected to the motor housing via a bearing, and the other end is connected to the sun gear 3211 via a key. The external teeth of the sun gear 3211 mesh with several planet gears 3213, which in turn mesh with the internal teeth of a gear ring mounted on the inner wall of the motor housing. One end of the planet carrier 3212 is connected to the planet gears 3213, and the other end is connected to one end of the lead screw 3221 via an interference fit. The outer wall of the lead screw 3221 is connected to a roller nut 3223 via rollers 3222. The roller nut 3223 is fixed to the motor housing via an transition fit. A cavity is cut in the housing at the fixing point, and a limit block is installed on the roller nut 3223. The outer end of the roller nut 3223 is... After the motor housing extends out, it is connected to a brake pad 304; two levers 3232 are symmetrically arranged on the outer circumferential wall of the roller nut 3223. The outer circumferential wall of the roller nut 3223 is hinged to one end of the two levers 3232 through a lever push shaft 3231. The other end of the two levers 3232 extends out of the motor housing and is hinged to one end of the outer brake caliper 3235 through a rotating pin 3234. A lever shaft 3233 is provided on the motor housing at the point where the levers 3232 extend out. The levers 3232 are hinged to the lever shaft 3233. One end of the outer brake caliper 3235 is connected to another brake pad 304. The disc brake 303 is arranged between the two brake pads 304; the brake motor controller 302 is electrically connected to the brake motor 301.

[0022] The brake motor controller 302 controls the motor rotor 3011 to start rotating. The motor rotor 3011 drives the sun gear 3211 to rotate via a key connection, which in turn drives the planet gears 3213 to rotate. The rotation of the planet gears 3213 around the sun gear 3211 is converted into the rotational motion of the planet carrier 3212 itself through the planet carrier 3212. The planet carrier 3212 drives the lead screw 3221 to rotate through the static friction generated by the interference fit with the lead screw 3221. This rotation is then transmitted to the roller nut 3223 through the rollers 3222 and converted into the linear motion of the roller nut 3223.

[0023] Simultaneously, the linear motion of the roller nut 3223 drives the lever push shaft 3231 connected to it to move linearly in the same direction as the roller nut 3223. Since the lever 3232 rotates around the lever shaft 3233, and the lever push shaft 3231 and the rotating pin 3234 are located on opposite sides of the rotation, the rotating pin 3234 oscillates in the opposite direction to the lever push shaft 3231. The rotating pin 3234 drives the outer brake caliper 3235 to oscillate in the same direction, thus ultimately achieving simultaneous braking of the brake pads 304 on both sides of the disc brake 303, thereby increasing the braking intensity.

[0024] As shown in Figures 1, 2 and 5, a method for distributing electromechanical braking torque in a mining dump truck includes a chassis controller 1, a power module 2, an electromechanical braking device 3 and a sensor module 4; the chassis controller 1, the electromechanical braking device 3 and the sensor module 4 are all electrically connected to the power module 2, and the electromechanical braking device 3 and the sensor module 4 are all electrically connected to the chassis controller 1.

[0025] Sensor module 4 includes a wheel speed sensor 401, a steering angle sensor 402, a clamping force sensor 403, a camera 404, a lidar 405, a millimeter-wave radar 406, an inertial navigator 407, and an inclinometer 408. The wheel speed sensor 401 and steering angle sensor 402 are located at the wheels of the dump truck; the clamping force sensor 403 is located at the disc brake 303; the camera 404, lidar 405, and millimeter-wave radar 406 are located at the front of the dump truck; and the inertial navigator 407 and inclinometer 408 are located at the front of the dump truck. 8 is located in the middle of the dump truck; among them, wheel speed sensor 401 collects dump truck speed information, steering angle sensor 402 collects front wheel steering angle information, clamping force sensor 403 collects clamping force signal during braking process, camera 404, lidar 405, and millimeter-wave radar 406 collect external environment information, inertial navigation system 407 collects dump truck position, speed, yaw rate, and center of gravity side slip angle information, and inclinometer 408 collects road slope. All information is transmitted to chassis controller 1 via CAN bus.

[0026] The power module 2 includes a 24V low-voltage power supply 201 and a 700V high-voltage power supply 202. The chassis controller 1, the brake motor controllers of each wheel 302, and the sensor module 4 are electrically connected to the 24V low-voltage power supply 201; the brake motors of each wheel 301 are electrically connected to the 700V high-voltage power supply 202.

[0027] The chassis controller 1, as the core component of the electromechanical braking torque distribution of the mining dump truck, includes a main controller 101 and an auxiliary controller 102. It receives various data provided by the sensor module 4. Based on this data, it determines the current braking demand and braking mode on the one hand, and calculates the braking torque of the specific braking mode and distributes it to the electromechanical braking execution unit 310 on the other hand.

[0028] Depending on the number of wheels on a dump truck, dump trucks typically have four or six wheels. The electromechanical braking module 3 is divided into four or six electromechanical braking execution units 310. The brake motor controller 302 of each electromechanical braking execution unit 310 receives the braking torque allocated by the chassis controller 1. The brake motor controller 302 controls the brake motor 301, and then controls the transmission mechanism 320 to ultimately achieve the braking target.

[0029] According to the braking sequence, the entire braking process is divided into two braking working modes defined based on the driving conditions of the mining dump truck, the identification and decision-making of the braking mode based on sensor signals, the calculation of braking torque based on sensor signals, and the output of braking torque through the braking actuator.

[0030] Based on the operating conditions of mining dump trucks, braking modes are defined into two categories: conventional braking mode and redundant braking mode. Conventional braking mode: The normal workflow of a mining dump truck is a cycle of "loading coal at the loading point—driving to the unloading point—unloading coal at the unloading point—driving to the loading point—loading coal at the loading point." The truck's route is a cycle of "loading / unloading point—loading / unloading area—mining branch road—mining main road—mining branch road—loading / unloading area—loading / unloading point." The main action of the dump truck from the loading / unloading point to the mining main road is driving, and the main action from the mining main road to the loading / unloading point is braking. Speed ​​limits are in place for each section: ≤40km / h on main roads, ≤35km / h on branch roads, and ≤20km / h in the loading / unloading area.

[0031] Based on the dump truck's driving route, its driving actions on each segment of the route, and the speed limits for each segment, a "conventional braking mode" is defined. This mode is designed for scenarios where "dump trucks need to reduce their speed to below a certain value when sequentially traveling through 'mining main road—mining branch road—loading and unloading area—loading and unloading point'." Three target deceleration rates are defined: 1 m / s² 2 2.5m / s 2 4m / s 2 .

[0032] When a dump truck travels from the main road to the branch road in the mining area, with "branch road in the mining area" as the target location and "1m / s", 2 "Decelerate to the target; when the dump truck travels from the mining area branch line to the loading and unloading area, take the 'loading and unloading area' as the target location, and '2.5m / s'..."2 "Decelerate to the target; when the dump truck travels from the loading and unloading area to the loading and unloading point, take the 'loading and unloading point' as the target location, and '4m / s' " 2 "Slow down the target."

[0033] Redundant Braking Mode: The conventional braking mode described above is an idealized one. In actual dump truck operation, unexpected situations may occur, such as motor explosion, bearing breakage, frame deformation, etc. These situations can lead to wheel failure, causing the vehicle to drift and affecting the braking process. In this case, it is necessary to redistribute the braking torque to ensure stable braking. Since many components of the electromechanical braking system can fail, it is not advisable to determine wheel failure by testing component damage. Therefore, the following method is adopted: Regardless of the type of damage, the conventional braking mode is first applied. A clamping force sensor 403 is installed on the disc brake 303. The presence or absence of the clamping force sensor 403 signal is used to determine whether the wheel has failed. After confirming failure, the specific braking torque is calculated and distributed.

[0034] In light of this unexpected situation beyond the conventional braking mode, a "redundant braking mode" is defined, which addresses the scenario where a dump truck experiences wheel failure in the "conventional braking mode".

[0035] Braking mode identification and decision-making are achieved based on sensor signals; Conventional braking mode: As shown in Figure 2, the wheel speed sensor 401 and the inertial navigation system 406 transmit the position and speed information of the dump truck to the main controller 101 through the CAN bus. After entering the section of "mining area trunk line - mining area branch line - loading and unloading operation area - loading and unloading point", the main controller 101 starts to calculate the "expected deceleration" required for the dump truck to travel to the next target location in real time, and compares the "expected deceleration" with the corresponding "target deceleration". When the "expected deceleration" and the "target deceleration" are close in value, the "conventional braking mode" is entered.

[0036] Redundant braking mode: When in "normal braking mode", as shown in Figure 2, the clamping force sensor 403 transmits the clamping force signal to the main controller 101 through the CAN bus. The main controller 101 determines whether the clamping force is online based on the transmitted signal. When it is not online, it enters "redundant braking mode".

[0037] Braking torque calculation is completed based on sensor signals. As shown in Figures 2 and 5, each sensor transmits relevant information about the dump truck to the main controller 101 via the CAN bus. Based on the various signals provided by the sensors, the dump truck is subjected to force analysis, dynamic modeling, and the upper layer of the controller uses sliding mode control to calculate the additional yaw moment. The lower layer of the controller allocates the braking torque with the optimization targets of ride comfort and road surface adhesion utilization. Finally, the braking torque allocation results under the two braking modes are obtained.

[0038] The braking torque distribution method for six-wheeled dump trucks and four-wheeled dump trucks is generally the same. The following example uses a six-wheeled dump truck.

[0039] Torque distribution of each wheel under normal braking mode: S1, calculation of reference braking torque: Since the distance and working conditions of the two rear wheels on the same side of the six-wheel dump truck are similar, in order to improve calculation efficiency, each of the two sets of rear wheels on the same side is equivalent to a single rear wheel, and the axis of symmetry of the two rear axles is taken as the equivalent rear axle. After equivalence, the six-wheel dump truck is simplified to a four-wheel dump truck. The normal force and longitudinal force of a single rear wheel are equal to the sum of the normal force and longitudinal force of the two rear wheels on the same side before equivalence. Based on the equivalent four-wheel dump truck, the force analysis of the vehicle is performed, and the normal forces on the front and rear wheels on horizontal roads and sloping roads are respectively: Horizontal road: ; Sloping road: In the formula: For the normal force of the front left wheel, For the normal force of the front right wheel, For the normal force of the rear left wheel, The normal force is that of the rear right wheel; This is the distance from the center of gravity to the front axle. ρ is the distance from the center of mass to the rear axle, m is the total mass of the vehicle, and g is the acceleration due to gravity. The height of the center of mass above the ground. The slope of the ramp. The acceleration of the dump truck is given; further, the maximum ground adhesion and maximum braking torque of the wheels can be obtained: ; In the formula: This represents the maximum ground adhesion of the wheels. The maximum braking torque of the wheel, The coefficient of friction between the wheels and the road surface. This is the actual normal force on the wheel. For the maximum ground adhesion of the front left wheel, For the maximum ground adhesion of the front right wheel, For the maximum ground adhesion of the rear left wheel, This represents the maximum ground adhesion of the rear right wheel; The maximum braking torque of the front left wheel, The maximum braking torque of the front right wheel, For the maximum braking torque of the rear left wheel, This is the maximum braking torque of the rear right wheel; For the front left wheel road adhesion coefficient, For the road surface adhesion coefficient of the front right wheel, For the rear left wheel road surface adhesion coefficient, The coefficient of friction for the rear right wheel; The actual normal force of the front left wheel, The actual normal force of the front right wheel, For the actual normal force of the rear left wheel, This represents the actual normal force on the rear right wheel; Let be the wheel rolling radius. When the actual braking torque of the wheel exceeds the maximum braking torque, it will cause the wheel to lock up. Therefore, the actual braking torque of the wheel must be less than the maximum braking torque. However, in order to achieve the braking target quickly, the actual braking torque of the wheel should be as large as possible. Therefore, considering both anti-lock braking and rapid braking, a safety factor is defined. (Suggested range: 0.8~0.95, to be determined based on actual needs), the braking torque of a single wheel is taken as: In the formula: This is the actual braking torque of the wheel. The actual braking torque of the front left wheel, The actual braking torque of the front right wheel, The actual braking torque of the rear left wheel, This is the actual braking torque of the rear right wheel; For safety factor; The maximum braking torque of the front left wheel, The maximum braking torque of the front right wheel, For the maximum braking torque of the rear left wheel, The maximum braking torque of the rear right wheel is given; ultimately, the reference braking torque of the dump truck is obtained: In the formula: As the reference braking torque; The actual braking torque of the front left wheel, The actual braking torque of the front right wheel, The actual braking torque of the rear left wheel, This is the actual braking torque of the rear right wheel.

[0040] S2, Calculate the additional yaw moment: Dump truck dynamics modeling: The dynamics of the dump truck are modeled using a linear two-degree-of-freedom model. The modeling results are as follows: In the formula: This is the yaw acceleration. The angular velocity of the center of mass deflection; The yaw rate is angular velocity. The sideslip angle is the angle of the center of mass. This is the distance from the center of gravity to the front axle. This is the distance from the center of gravity to the rear axle. For front axle lateral stiffness, For rear axle lateral stiffness, Let v be the moment of inertia of the dump truck about the z-axis (the z-axis is a coordinate axis passing through the dump truck's center of mass and perpendicular to the ground); v is the speed of the dump truck; and m is the mass of the entire vehicle. The above dynamic model of the dump truck describes all driving conditions, while the yaw rate of the dump truck under stable driving conditions is... and centroid side slip angle All are constants, therefore the yaw acceleration and the angular velocity of the center of mass deflection All are 0, =0、 Substituting 0 into the dump truck dynamics model, we get: ; with yaw rate and centroid side slip angle Solving this system of equations for the unknowns yields: The parameters obtained by the above two formulas are the yaw rate under stable driving conditions. and centroid side slip angle yaw rate and centroid side slip angle Stable driving is achieved when the above two formulas are satisfied; that is, these two formulas represent the ideal yaw rate for maintaining stable driving of a dump truck. And the ideal centroid side slip angle ,in For the wheelbase of the dump truck, then the complex constants in the formula are... Defined separately as the stability coefficient K of the dump truck, the ideal yaw rate can ultimately be obtained. And the ideal centroid side slip angle They are respectively: In the formula: For the ideal yaw rate, The ideal centroid sideslip angle; This is the distance from the center of gravity to the front axle. This is the distance from the center of gravity to the rear axle. Where is the wheelbase of the dump truck, and K is the stability coefficient of the dump truck. denoted as , where v is the rear axle lateral stiffness, v is the dump truck's speed, and m is the vehicle's mass. The front wheel steering angle is used; the upper-level controller aims at stability and employs a simple, interference-resistant sliding mode control algorithm. The two main parameters describing stability are yaw rate and lateral velocity. and centroid side slip angle Therefore, the control torque is first calculated for each of the two control targets. After analysis, the following can be obtained: Yaw angular velocity braking torque: ;in, , , In the formula: The braking torque is the yaw rate. For the ideal yaw rate, For the ideal yaw acceleration, The yaw rate is angular velocity. This is the yaw acceleration. The sideslip angle is the angle of the center of mass. The angular velocity of the center of mass deflection. This is the distance from the center of gravity to the front axle. This is the distance from the center of gravity to the rear axle. For front axle lateral stiffness, For rear axle lateral stiffness, Let v be the moment of inertia of the vehicle about the z-axis (the z-axis is a coordinate axis passing through the center of mass of the dump truck and perpendicular to the ground), and v be the speed of the dump truck. For the front wheel steering angle, The front wheel angular acceleration, This represents the relative weighting coefficient between the yaw rate error and the change in error. To achieve a yaw rate gain, The yaw rate is the power coefficient, and sgn is the sign function; the braking torque at the center of mass sideslip angle is: ;in, , , In the formula: The braking torque is the sideslip angle of the center of gravity. The yaw rate is angular velocity. For the ideal centroid sideslip angle, For the ideal centroid sideslip angular velocity, The sideslip angular acceleration of the center of mass. The sideslip angle is the angle of the center of mass. The angular velocity of the center of mass deflection. This is the distance from the center of gravity to the front axle. This is the distance from the center of gravity to the rear axle. For front axle lateral stiffness, For rear axle lateral stiffness, Let m be the vehicle's moment of inertia about the z-axis (the z-axis is a coordinate axis passing through the dump truck's center of mass and perpendicular to the ground), m be the vehicle's mass, and v be the dump truck's speed. For the front wheel steering angle, The front wheel angular acceleration, This represents the relative weighting coefficient between the centroid sideslip angle error and the error variation. To achieve the gain as the centroid sideslip angle approaches, Let be the power coefficient of the sideslip angle, and sgn be the sign function. On the one hand, if the yaw rate and sideslip angle are controlled by two separate controllers, it will lead to control conflict, thereby reducing control performance. On the other hand, under different conditions, the degree to which the actual yaw rate and the actual sideslip angle deviate from the ideal value has an inverse relationship, that is, when the actual yaw rate deviates significantly from the ideal value, the actual sideslip angle deviates little from the ideal value, and vice versa. The weighting formula for the degree of deviation between the two is as follows: In the formula: These are the weighting coefficients; The sideslip angle is the angle of the center of mass. The angular velocity of the center of mass deflection; The threshold parameter is determined by the road surface adhesion coefficient. The decision was made to adjust the road surface adhesion coefficient. and threshold parameters The numerical relationships are created in a table and pre-entered into the auxiliary controller 102, which then calculates the road surface adhesion coefficient. At the same time, look up the corresponding threshold parameter in the table. Both are simultaneously transmitted to the main controller 101; considering both aspects, and taking into account the complementary relationship between the yaw rate and the deviation of the center of gravity from the sideslip angle, the weighting coefficients are used... yaw rate braking torque and the braking torque of the center of gravity sideslip angle Combined into a total additional yaw moment Ultimately, the additional yaw moment of the dump truck was obtained. : In the formula: To add yaw moment; These are the weighting coefficients. The braking torque is the yaw rate. The braking torque is the sideslip angle of the center of mass.

[0041] S3, Constraints on Reference Braking Torque and Additional Yaw Moment: Through the above analysis, the values ​​of the reference braking torque and additional yaw moment were obtained. The reference braking torque is used to quickly achieve the braking target; the additional yaw moment is used to create a torque difference between the two wheels, allowing the dump truck to actively generate yaw moment to cancel out the torque generated by instability, thus maintaining the stability of the dump truck. Therefore, in order to balance the speed and stability of braking, the reference braking torque and additional yaw moment need to be superimposed and distributed to each wheel. Therefore, the "braking torque constraint relationship" between the target braking torque, reference braking torque, and additional yaw moment of each wheel is as follows: In the formula: For the target braking torque of the front left wheel, The target braking torque for the front right wheel, For the target braking torque of the rear left wheel, The target braking torque for the rear right wheel; As the reference braking torque, To add yaw moment, The radius of the wheel's rolling motion. This refers to the front and rear wheel track of the dump truck. The front wheel steering angle is defined by this formula. Through the constraint relationships between the target braking torque, reference braking torque, and additional yaw torque of each wheel, braking speed and stability are achieved. Next, under these constraints, the calculated reference braking torque and additional yaw torque will be distributed to each wheel according to different optimization objectives for different braking modes.

[0042] In normal braking mode, the lower-level controller optimizes for smoothness: to avoid shocks caused by differences in braking torque between different wheels, the baseline braking torque should ideally be evenly distributed across all wheels. However, to maintain stability, additional yaw moment and braking torque constraints, as mentioned earlier, are provided separately, making differences in braking torque between different wheels unavoidable. Under this premise, to ensure that the total braking torque ultimately distributed to each wheel is as close as possible, the objective function is defined, analogous to the mathematical definition of variance: ;in, In the formula: The objective function is... For the target braking torque of the wheels, For the target braking torque of the front left wheel, The target braking torque for the front right wheel, For the target braking torque of the rear left wheel, The target braking torque for the rear right wheel; objective function When the minimum value is taken, the difference in actual braking torque between each wheel is the smallest; the actual braking torque of each wheel calculated at this point is the target braking torque. Therefore, , Substitution By taking the partial derivative, the target braking torque can be obtained as: In the formula: For the target braking torque of the rear left wheel, The target braking torque for the rear right wheel; As the reference braking torque, To add yaw moment, The radius of the wheel's rolling motion. This refers to the front and rear wheel track of the dump truck. This refers to the steering angle of the front wheels.

[0043] Then , Substituting the braking torque constraint relationship, we can obtain , For ease of calculation, the two sets of rear wheels on the same side were each represented as a single rear wheel. , It is the target braking torque for a single rear wheel, which is ultimately divided equally when applied to the two sets of rear wheels on the same side. In the formula: For the target braking torque of the left wheel, For the target braking torque of the right wheel, For the target braking torque of the rear left wheel, The target braking torque for the rear right wheel; As the reference braking torque, To add yaw moment, The radius of the wheel's rolling motion. This refers to the front and rear wheel track of the dump truck. Front wheel steering angle; final braking torque distribution to the six wheels: ; In the formula: For the target braking torque of the front left wheel, The target braking torque for the front right wheel, For the target braking torque of the left wheel, For the target braking torque of the right wheel, For the target braking torque of the rear left wheel, The target braking torque for the rear right wheel; As the reference braking torque, To add yaw moment, The radius of the wheel's rolling motion. This refers to the front and rear wheel track of the dump truck. The front wheel steering angle is determined by the braking torque result achieved by each brake motor controller 302 through its corresponding electromechanical brake actuator 310. If the clamping force is online, braking continues until the braking target is achieved; if the clamping force is offline, redundant braking mode is entered.

[0044] In redundant braking mode, the base braking torque and additional yaw torque are calculated in the same way as in conventional braking mode, so they will not be repeated here. The difference lies in the optimization target of the lower-level controller.

[0045] In redundant braking mode, the lower-level controller optimizes road surface adhesion utilization. The previously calculated baseline braking torque is the sum of the braking torques of each wheel approaching maximum ground adhesion. This baseline braking torque ensures from the outset that the actual braking torque distributed to each wheel is not too small, thus improving braking speed. In this redundant braking mode, in addition to considering braking speed, braking safety also needs to be considered. Therefore, to prevent wheel lock-up, the lower-level controller needs to minimize the road surface adhesion utilization of each wheel when distributing torque, thereby keeping each wheel away from maximum ground adhesion and ensuring safety. Based on the "friction ellipse theory," the objective function is defined as follows: In the formula: The objective function is... This represents the actual longitudinal force on the wheel. The actual longitudinal force of the front left wheel The actual longitudinal force of the front right wheel, For the actual longitudinal force of the rear left wheel, This represents the actual longitudinal force on the rear right wheel; This represents the actual longitudinal force on the wheel. The actual lateral force of the front left wheel, The actual lateral force of the front right wheel, The actual lateral force of the rear left wheel, This represents the actual lateral force on the rear right wheel; For the front left wheel road adhesion coefficient, For the road surface adhesion coefficient of the front right wheel, For the rear left wheel road surface adhesion coefficient, The coefficient of friction for the rear right wheel; The actual normal force of the front left wheel, The actual normal force of the front right wheel, For the actual normal force of the rear left wheel, This represents the actual normal force on the rear right wheel; For the target braking torque of the front left wheel, The target braking torque for the front right wheel, For the target braking torque of the rear left wheel, The target braking torque for the rear right wheel; Let the wheel's rolling radius be ; objective function be . In the equation, the numerator is the vector sum of the longitudinal and lateral forces acting on the wheel, and the denominator is the maximum allowable ground adhesion force for the wheel. When the numerator is greater than the denominator, the wheel will lock up; when the numerator is smaller than and close to the denominator, the wheel is at high risk of locking up; when the numerator is much smaller than the denominator, the wheel will basically not lock up. Therefore, the objective function is... The smaller the value, the further the actual braking torque of the wheels is from the maximum braking torque, the less likely the wheels are to lock up, and the safer the dump truck. Therefore, the objective function... The distributed torque at its minimum value is the target braking torque; as mentioned earlier. The following relationship exists between them: In the formula: This is the actual braking torque of the front left wheel. This is the actual braking torque of the front right wheel. This refers to the actual braking torque of the rear left wheel. This is the actual braking torque of the rear right wheel; As the reference braking torque, To add yaw moment, The radius of the wheel's rolling motion. This refers to the front and rear wheel track of the dump truck. This refers to the steering angle of the front wheels.

[0046] Will , Substitution By taking the partial derivative, the target braking torque can be obtained as: Then , Substituting the braking torque constraint relationship, we can obtain , In the formula: For the target braking torque of the rear left wheel, The target braking torque for the rear right wheel; For the front left wheel road adhesion coefficient, For the road surface adhesion coefficient of the front right wheel, For the rear left wheel road surface adhesion coefficient, The coefficient of friction for the rear right wheel; The actual normal force of the front left wheel, The actual normal force of the front right wheel, For the actual normal force of the rear left wheel, This represents the actual normal force on the rear right wheel; As the reference braking torque, To add yaw moment, The radius of the wheel's rolling motion. This refers to the front and rear wheel track of the dump truck. The steering angle of the front wheels; , It is the target braking torque for a single rear wheel, which is ultimately divided equally when applied to the two sets of rear wheels on the same side. In the formula: For the target braking torque of the left wheel, For the target braking torque of the right wheel, For the target braking torque of the rear left wheel, The target braking torque for the rear right wheel; For the front left wheel road adhesion coefficient, For the road surface adhesion coefficient of the front right wheel, For the rear left wheel road surface adhesion coefficient, The coefficient of friction for the rear right wheel; The actual normal force of the front left wheel, The actual normal force of the front right wheel, For the actual normal force of the rear left wheel, This represents the actual normal force on the rear right wheel; As the reference braking torque, To add yaw moment, The radius of the wheel's rolling motion. This refers to the front and rear wheel track of the dump truck. This refers to the steering angle of the front wheels.

[0047] Final braking torque distribution results for the six wheels: ; In the formula: For the target braking torque of the front left wheel, The target braking torque for the front right wheel, For the target braking torque of the left wheel, For the target braking torque of the right wheel, For the target braking torque of the rear left wheel, The target braking torque for the rear right wheel; For the front left wheel road adhesion coefficient, For the road surface adhesion coefficient of the front right wheel, For the rear left wheel road surface adhesion coefficient, The coefficient of friction for the rear right wheel; The actual normal force of the front left wheel, The actual normal force of the front right wheel, For the actual normal force of the rear left wheel, This represents the actual normal force on the rear right wheel; As the reference braking torque, To add yaw moment, The radius of the wheel's rolling motion. This refers to the front and rear wheel track of the dump truck. The front wheel steering angle is given; each brake motor controller 302 controls its corresponding electromechanical brake actuator 310 to achieve the above braking torque result, and continues braking until the speed is reduced to 0.

[0048] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any minor modifications, equivalent substitutions, and improvements made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. An electromechanical braking device for a mining dump truck, characterized in that, The system includes an electromechanical braking actuator (310), which comprises a brake motor (301), a brake motor controller (302), a disc brake (303), brake pads (304), and a transmission mechanism (320). The brake motor (301) includes a motor rotor (3011) and a motor stator (3012). The transmission mechanism (320) includes a planetary gear (321), a ball screw (322), and a lever mechanism (323). The gear (321) includes a sun gear (3211), a planet carrier (3212), and planet gears (3213); the roller screw (322) includes a screw (3221), rollers (3222), and roller nuts (3223); the lever mechanism (323) includes a lever (3232) and an outer brake caliper (3235); the motor stator (3012) is mounted on the inner wall of the motor housing, and one end of the output shaft of the motor rotor (3011) is connected to the motor housing via a bearing, and the other end is connected via a key. The sun gear (3211) is connected to the sun gear (3211), whose external teeth mesh with several planet gears (3213). The planet gears (3213) mesh with the internal teeth of the gear ring, which is located on the inner wall of the motor housing. One end of the planet carrier (3212) is connected to the planet gears (3213), and the other end is connected to one end of the lead screw (3221). The outer wall of the lead screw (3221) is connected to the roller nut (3223) through rollers (3222). The outer end of the roller nut (3223) protrudes from the motor housing. It is then connected to a brake pad (304); the outer circumferential wall of the roller nut (3223) is hinged to one end of the lever (3232), the other end of the lever (3232) passes through the motor housing and is hinged to one end of the outer brake caliper (3235), one end of the outer brake caliper (3235) is connected to another brake pad (304), and the disc brake (303) is set between the two brake pads (304); the brake motor controller (302) is electrically connected to the brake motor (301).

2. The electromechanical braking device for a mining dump truck according to claim 1, characterized in that: A lever shaft (3233) is provided on the motor housing where the lever (3232) passes through, and the lever (3232) is hinged to the lever shaft (3233).

3. The electromechanical braking device for a mining dump truck according to claim 2, characterized in that: The roller nut (3223) has two levers (3232) symmetrically arranged on its outer circumferential wall.

4. A method for distributing electromechanical braking torque in a mining dump truck, characterized in that, Includes a chassis controller (1), a power module (2), an electromechanical braking device (3) as described in any of claims 1-3, and a sensor module (4); the chassis controller (1), the electromechanical braking device (3), and the sensor module (4) are all electrically connected to the power module (2), and the electromechanical braking device (3) and the sensor module (4) are all electrically connected to the chassis controller (1); the torque distribution of each wheel under normal braking mode: S1, calculating the reference braking torque: the normal forces on the front and rear wheels of the dump truck on horizontal roads and sloping roads are respectively: horizontal roads: ; Sloping road: In the formula: For the normal force of the front left wheel, For the normal force of the front right wheel, For the normal force of the rear left wheel, The normal force is that of the rear right wheel; This is the distance from the center of gravity to the front axle. ρ is the distance from the center of mass to the rear axle, m is the total mass of the vehicle, and g is the acceleration due to gravity. The height of the center of mass above the ground. The slope of the ramp. The acceleration of the dump truck is given; further, the maximum ground adhesion and maximum braking torque of the wheels can be obtained: ； In the formula: This represents the maximum ground adhesion of the wheels. The maximum braking torque of the wheel, The coefficient of friction between the wheels and the road surface. This is the actual normal force on the wheel. Let the wheel rolling radius be denoted as ; considering both anti-lock braking and rapid braking scenarios, a safety factor is defined, and the braking torque of a single wheel is taken as : In the formula: This represents the actual braking torque of the wheels; ultimately, the reference braking torque of the dump truck is obtained: In the formula: S2 is the reference braking torque; S2, calculate the additional yaw moment: use a linear two-degree-of-freedom model to perform dynamic modeling of the dump truck, and the modeling results are as follows: In the formula: This is the yaw acceleration. The angular velocity of the center of mass deflection; The yaw rate is angular velocity. The sideslip angle is the angle of the centroid. For front axle lateral stiffness, For rear axle lateral stiffness, Let v be the moment of inertia of the dump truck about the z-axis; v is the speed of the dump truck. The front wheel steering angle; the yaw rate of the dump truck under stable driving conditions. and centroid side slip angle All are constants, therefore the yaw acceleration and the angular velocity of the center of mass deflection All are 0, =0、 Substituting 0 into the dump truck dynamics model, we get: ; with yaw rate and centroid side slip angle Solving this system of equations for the unknowns yields: The two formulas above represent the ideal yaw rate for maintaining stable driving of a dump truck. And the ideal centroid side slip angle ,in For the wheelbase of the dump truck, then the complex constants in the formula are... Defined separately as the stability coefficient K of the dump truck, the ideal yaw rate can ultimately be obtained. And the ideal centroid side slip angle They are respectively: The upper-level controller uses stability as its control objective, and the two parameters describing stability are yaw rate. and centroid side slip angle Therefore, the control torque is first calculated for these two control objectives: yaw rate braking torque: ;in, ， ， In the formula: The braking torque is the yaw rate. For the ideal yaw acceleration, The front wheel angular acceleration, This represents the relative weighting coefficient between the yaw rate error and the change in error. To achieve a yaw rate gain, The yaw rate is the power coefficient, and sgn is the sign function; the braking torque at the center of mass sideslip angle is: ;in, ， ， In the formula: The braking torque is the sideslip angle of the center of gravity. For the ideal centroid sideslip angular velocity, The sideslip angular acceleration of the center of mass. This represents the relative weighting coefficient between the centroid sideslip angle error and the error variation. To achieve the gain as the centroid sideslip angle approaches, This represents the power coefficient of the sideslip angle; the actual yaw rate and the actual sideslip angle deviate from the ideal value in opposite directions, and the weighting formulas for their deviations are as follows: In the formula: These are the weighting coefficients; The threshold parameter is determined by the road surface adhesion coefficient. Decision; using weighting coefficients yaw rate braking torque and the braking torque of the center of gravity sideslip angle Combined into a total additional yaw moment ： S3, Constraints on Reference Braking Torque and Additional Yaw Moment: To balance braking speed and stability, the reference braking torque and additional yaw moment need to be superimposed and distributed to each wheel. Therefore, the "braking torque constraint relationship" between the target braking torque, reference braking torque, and additional yaw moment of each wheel is as follows: In the formula: For the target braking torque of the front left wheel, The target braking torque for the front right wheel, For the target braking torque of the rear left wheel, The target braking torque for the rear right wheel; The distance between the front and rear wheels of the dump truck; under normal braking mode, the lower-level controller optimizes for smoothness: following the definition of variance in mathematics, the objective function is defined as: ;in, In the formula: The target braking torque for the wheels; objective function When the minimum value is taken, the difference in actual braking torque between each wheel is the smallest; the actual braking torque of each wheel calculated at this point is the target braking torque. Therefore, 、 Substitution By taking the partial derivative, the target braking torque can be obtained as: Then 、 Substituting the braking torque constraint relationship, we can obtain 、 Each brake motor controller (302) achieves the above braking torque result by controlling its corresponding electromechanical brake actuator (310). If the clamping force is online, the braking continues until the braking target is achieved; if the clamping force is offline, the redundant braking mode is entered.

5. The electromechanical braking torque distribution method for a mining dump truck according to claim 4, characterized in that: The torque distribution of each wheel in the redundant braking mode: In the redundant braking mode, the lower-level controller optimizes the road surface adhesion utilization rate: Based on the "friction ellipse theory", the objective function is defined as follows: In the formula: The objective function is... This represents the actual longitudinal force on the wheel. The actual longitudinal force of the wheel; objective function The distributed torque at its minimum value is the target braking torque; as mentioned earlier. The following relationship exists between them: ;Will 、 Substitution By taking the partial derivative, the target braking torque can be obtained as: Then 、 Substituting the braking torque constraint relationship, we can obtain 、 Each brake motor controller (302) achieves the above-mentioned braking torque result by controlling its corresponding electromechanical brake actuator (310), and continues braking until the speed is reduced to 0.

6. A method for distributing electromechanical braking torque in a mining dump truck according to claim 4 or 5, characterized in that: When the dump truck has six wheels, the distance and working conditions of the two rear wheels on the same side are similar. Each of the two sets of rear wheels on the same side is equivalent to a single rear wheel, and the axis of symmetry of the two rear axles is taken as the equivalent rear axle. The equivalent six-wheel dump truck is simplified to a four-wheel dump truck. The normal force and longitudinal force of a single rear wheel are equal to the sum of the normal force and longitudinal force of the two rear wheels on the same side before the equivalent designation. Conventional braking mode: 、 It is the target braking torque for a single rear wheel, which is ultimately divided equally when applied to the two sets of rear wheels on the same side. The final result of the braking torque distribution to the six wheels is as follows: ； In the formula: For the target braking torque of the front left wheel, The target braking torque for the front right wheel, For the target braking torque of the left wheel, For the target braking torque of the right wheel, For the target braking torque of the rear left wheel, The target braking torque for the rear right wheel; As the reference braking torque, To add yaw moment, The radius of the wheel's rolling motion. This refers to the front and rear wheel track of the dump truck. Front wheel steering angle; Redundant braking mode: 、 It is the target braking torque for a single rear wheel, which is ultimately divided equally when applied to the two sets of rear wheels on the same side. ； Final braking torque distribution results for the six wheels: ； In the formula: For the target braking torque of the front left wheel, The target braking torque for the front right wheel, For the target braking torque of the left wheel, For the target braking torque of the right wheel, For the target braking torque of the rear left wheel, The target braking torque for the rear right wheel; For the front left wheel road adhesion coefficient, For the road surface adhesion coefficient of the front right wheel, For the rear left wheel road surface adhesion coefficient, The coefficient of friction for the rear right wheel; The actual normal force of the front left wheel, The actual normal force of the front right wheel, For the actual normal force of the rear left wheel, This represents the actual normal force on the rear right wheel; As the reference braking torque, To add yaw moment, The radius of the wheel's rolling motion. This refers to the front and rear wheel track of the dump truck. This refers to the steering angle of the front wheels.

7. The electromechanical braking torque distribution method for a mining dump truck according to claim 5, characterized in that: The sensor module (4) includes a wheel speed sensor (401), a turning angle sensor (402), a clamping force sensor (403), a camera (404), a lidar (405), a millimeter-wave radar (406), an inertial navigator (407), and an inclinometer (408). The wheel speed sensor (401) and the turning angle sensor (402) are located at the wheels of the dump truck, the clamping force sensor (403) is located at the disc brake (303), the camera (404), the lidar (405), and the millimeter-wave radar (406) are located at the front of the dump truck, and the inertial navigator (407) and the inclinometer (408) are located in the middle of the dump truck.

8. The electromechanical braking torque distribution method for a mining dump truck according to claim 7, characterized in that: The power module (2) includes a 24V low-voltage power supply (201) and a 700V high-voltage power supply (202). The chassis controller (1), the brake motor controller (302) of each wheel, and the sensor module (4) are electrically connected to the 24V low-voltage power supply (201); the brake motor (301) of each wheel is electrically connected to the 700V high-voltage power supply (202).

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