A dynamic joint braking algorithm for electro-hydraulic multi-systems of heavy-duty shuttle cars used in mines

Abstract

The present invention belongs to the field of travel control of heavy-duty shuttle vehicles for mining, and provides an electro-hydraulic multi-system dynamic joint braking algorithm for heavy-duty shuttle vehicles for mining, which solves the problem that the braking force is difficult to accurately control when the vehicle brake pedal is purely hydraulically controlled. The vehicle controller samples the travel motor speed, vehicle load, accelerator pedal signal, brake pedal signal, controller bus voltage, etc. in real time, and combines the road conditions and other fixed parameters of the vehicle to perform data calculation, and finally obtains the real-time electric braking torque required by each wheel when the vehicle brakes (the real-time reverse torque required to be output by each travel motor), sends the command to the travel motor controller, and cooperates with the hydraulic braking of the brake pedal to achieve electro-hydraulic multi-system dynamic joint braking.

Description

Technical Field

[0001] The invention belongs to the field of travel control of a heavy-duty shuttle car for mining, and in particular relates to an electro-hydraulic multi-system dynamic combined braking algorithm for a heavy-duty shuttle car for mining. Background Art

[0002] Heavy shuttle cars in coal mines are responsible for transporting coal during the mining process. In the past, the braking system of such vehicles was relatively simple, mostly using pure hydraulic braking, which achieved the braking and stopping of the entire vehicle by controlling the hydraulic brake pedal and increasing the braking force of the hydraulic circuit. For heavy vehicles, this braking method often has a hard characteristic, and the braking force is difficult to control accurately. If the brake pedal opening is small, the vehicle braking effect is not obvious, and a large opening will cause drastic changes in the braking force, and the vehicle's operability and driving comfort are poor. At the same time, as the vehicle ages, and the vehicle needs to frequently accelerate, decelerate, and brake under certain working conditions, the performance of the hydraulic brake components declines or even gets damaged, and the braking capacity gradually decreases. Summary of the invention

[0003] In order to solve at least one of the above technical problems existing in the prior art, the present invention provides an electro-hydraulic multi-system dynamic combined braking algorithm for a heavy-duty shuttle car for mining.

[0004] The present invention is implemented by the following technical solution: a dynamic combined braking algorithm of electro-hydraulic multi-system for heavy-duty shuttle vehicles for mining, comprising the following steps:

[0005] S1: Real-time synchronous acquisition of the opening signals of the accelerator pedal and the brake pedal, the pressure signal of the hydraulic brake circuit, the tire load pressure signal, the speed and direction signals of each travel motor, and the bus voltage signal of each travel motor controller;

[0006] S2: Generate a speed constraint coefficient, a voltage constraint coefficient and a hydraulic brake coefficient respectively according to the collected speed signals of each travel motor, the bus voltage signals of each travel motor controller and the pressure signals of the hydraulic brake circuit;

[0007] S3: Generates the electric braking force required for braking the front two wheels, the middle two wheels, and the rear two wheels based on the speed constraint coefficient, the hydraulic braking coefficient, the tire load pressure, and the road friction coefficient;

[0008] S4: Generate the electric braking torque required by each wheel according to the electric braking force required by each wheel, the speed constraint coefficient, the voltage constraint coefficient, the road friction coefficient, and the reduction ratio of the tire reducer;

[0009] S5: Based on the electric braking torque required for each wheel obtained in S4, within the travel range of the brake pedal of 0-L1, the vehicle controller controls each travel motor to output the corresponding counter-torque to realize electric braking of the vehicle; within the travel range of the brake pedal of L1-1, the vehicle controller controls each travel motor to continuously output the counter-torque, and combines it with the hydraulic braking of the brake pedal to realize the electric-hydraulic combined braking of the vehicle.

[0010] Preferably, in step S1, a pressure sensor is provided on the hydraulic circuit where the brake pedal is located to measure the pressure signal of the hydraulic brake circuit; the rotation speed of each travel motor is measured by a rotary transformer or an encoder, and the bus voltage of each travel motor controller is measured by a voltage meter.

[0011] Preferably, in step S2, the electric braking torque required for each wheel is constrained according to the collected rotation speed of each travel motor, and the speed constraint coefficient is calculated as follows:

[0012]

[0013] Among them, V is the real-time speed of the motor during vehicle driving, Vmax is the maximum speed of the motor under normal working conditions, Vmin is the minimum speed of the electric brake, and k v is the speed constraint coefficient.

[0014] Preferably, in step S2, the electric braking torque required by each wheel is constrained according to the bus voltage collected from each motor controller, and the calculation formula of the bus voltage constraint coefficient is as follows:

[0015]

[0016] Among them, U is the bus voltage of each motor controller, U n is the rated working voltage of the motor controller, Umax is the limit working voltage of the motor controller, k u is the bus voltage constraint coefficient.

[0017] Preferably, in step S2, the electric braking torque required for each wheel is constrained according to the collected hydraulic brake circuit pressure, and the hydraulic brake coefficient calculation formula is as follows:

[0018]

[0019] Among them, F b is the measured hydraulic brake circuit pressure, F bmax is the maximum pressure of the hydraulic brake circuit, k b is the hydraulic braking coefficient.

[0020] Preferably, in steps S3 and S4, since the influence of the external load on the force of the front two wheels can be ignored, the electric braking torque required by the front two wheels can be considered to be only related to the vehicle speed and the driver's braking intention, and is not affected by the load. The calculation formula of the braking torque of the front two wheels is as follows:

[0021] T 12 =T max *k b *k v *k u

[0022] Among them, T 12 is the electric braking torque required for the front two wheels, T max is the maximum braking torque allowed by the motor, k v is the speed constraint coefficient, k b is the hydraulic braking coefficient, k u is the bus voltage constraint coefficient;

[0023] The external load is considered to be borne by the middle two wheels and the rear two wheels. The electric braking force required by the middle two wheels and the rear two wheels is calculated as follows:

[0024] F 34 =F3*f*k b *(1+1.07*f*k b )

[0025] F 56 =2*F3*f*k b -F 34

[0026] where F 34 is the electric braking force required for the middle two wheels, F 56 is the electric braking force required for the rear two wheels, f is the road friction coefficient, F3 is the bearing pressure of a single intermediate wheel or rear wheel, k b is the hydraulic braking coefficient;

[0027] It should be pointed out that the above formula is the electric braking torque required by the middle two wheels and the rear two wheels when the vehicle is moving forward. When moving backward, the two are opposite, that is,

[0028] F 34 =2*F3*f*k b -F 56

[0029] F 56 =F3*f*k b *[1+1.07*f*k b ]

[0030] Among them, F 34 is the electric braking force required for the middle two wheels, F 56is the electric braking force required for the rear two wheels, f is the road friction coefficient, F3 is the bearing pressure of a single intermediate wheel or rear wheel, k b is the hydraulic braking coefficient.

[0031] Preferably, in step S4, the calculation formula for the electric braking torque required by the middle two wheels and the rear two wheels is:

[0032]

[0033]

[0034] Among them, F 34 is the electric braking force required for the middle two wheels, F 56 is the electric braking force required for the rear two wheels, f is the road friction coefficient, i is the reduction ratio of the tire reducer, k v is the speed constraint coefficient, k u is the bus voltage constraint coefficient; T 34 is the electric braking torque required for the middle two wheels, T 56 The electric braking torque required for the rear two wheels.

[0035] Preferably, in step S5, within the brake pedal stroke interval 0-L1, the counter-torque output by each travel motor increases with the increase of the brake pedal stroke; within the brake pedal stroke interval L1-1, the counter-torque output by each travel motor reaches and remains maximum, and the hydraulic braking force gradually increases.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention samples the travel motor speed, vehicle load, accelerator pedal signal, brake pedal signal, controller bus voltage, etc. in real time through the vehicle controller, and performs data solution in combination with the road conditions and other fixed parameters of the vehicle, and finally obtains the real-time electric braking torque required by each wheel when the vehicle brakes (the real-time reverse torque required to be output by each travel motor), and sends the command to the travel motor controller, which cooperates with the hydraulic braking of the brake pedal to realize dynamic joint braking of multiple electro-hydraulic systems, making the braking process of the vehicle smoother, so as to improve the braking performance and driving comfort of the vehicle. It is a dynamic transformation and fusion process of multiple systems.

[0038] The algorithm in this application analyzes and calculates the electric braking torque of the vehicle. The main factors affecting the output of the electric braking torque are the depth of the brake pedal, the load of each electric wheel, the friction coefficient of the road surface, the driving direction, and the performance of the motor itself. At the same time, the range of the motor's braking torque is constrained, and the hydraulic braking coefficient, the motor speed constraint coefficient, and the controller bus voltage constraint coefficient are introduced. This not only completes the multi-factor dynamic adjustment of the motor's counter-torque output, but also realizes the protection of the motor and its controller, reduces mechanical brake wear, improves the life of the brake, and the safety and adaptability of the entire machine braking. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 It is a vehicle braking flow chart in the present invention;

[0041] Figure 2 The motor speed constraint coefficient diagram of the present invention (V min Take 300, V max Take 4500);

[0042] Figure 3 is the bus voltage constraint coefficient of the present invention (U n Take 240, U max Take 320);

[0043] Figure 4 This is the electric feedback braking and hydraulic braking control effect curve of the present invention (L1 in the figure is taken as 1 / 3). DETAILED DESCRIPTION

[0044] In conjunction with the drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings in this specification are only used to match the contents disclosed in the specification so that people familiar with this technology can understand and read them. They are not used to limit the conditions under which the present invention can be implemented, so they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention. It should be noted that in this specification, relational terms such as first and second are only used to distinguish one entity from other entities, and do not necessarily require or imply any actual relationship or order between these entities.

[0046] The present invention provides an embodiment:

[0047] A dynamic combined braking algorithm of electro-hydraulic multi-systems for heavy-duty shuttle cars for mining includes the following steps:

[0048] S1: Real-time synchronous acquisition of the opening signals of the accelerator pedal and the brake pedal, the pressure signal of the hydraulic brake circuit, the tire load pressure signal, the speed and direction signals of each travel motor, and the bus voltage signal of each travel motor controller;

[0049] S2: Generate a speed constraint coefficient, a voltage constraint coefficient and a hydraulic brake coefficient respectively according to the collected speed signals of each travel motor, the bus voltage signals of each travel motor controller and the pressure signals of the hydraulic brake circuit;

[0050] S3: Generates the electric braking force required for braking the front two wheels, the middle two wheels, and the rear two wheels based on the speed constraint coefficient, the hydraulic braking coefficient, the tire load pressure, and the road friction coefficient;

[0051] S4: Generate the electric braking torque required by each wheel according to the electric braking force required by each wheel, the speed constraint coefficient, the voltage constraint coefficient, the road friction coefficient, and the reduction ratio of the tire reducer;

[0052] S5: Based on the electric braking torque required for each wheel obtained in S4, within the travel range of the brake pedal of 0-L1, the vehicle controller controls each travel motor to output the corresponding counter-torque to realize electric braking of the vehicle; within the travel range of the brake pedal of L1-1, the vehicle controller controls each travel motor to continuously output the counter-torque, and combines it with the hydraulic braking of the brake pedal to realize the electric-hydraulic combined braking of the vehicle.

[0053] In step S1, the accelerator pedal and brake pedal openings usually form an angle range physically. The accelerator pedal opening usually generates a corresponding electrical signal, such as a voltage signal, a current signal or other communication signal. The accelerator pedal opening can be converted into a specific and easily identifiable numerical range through mathematical conversion or communication protocol conversion. The brake pedal is located in the hydraulic brake circuit, which can control the output braking force of the hydraulic brake system. A pressure sensor or other pressure measuring device is added to the hydraulic circuit to measure the brake pressure. The speed of each electric wheel can be measured by the motor's rotary transformer, encoder or other speed measuring device. Each motor controller can obtain its own bus voltage data, or it can be obtained through a voltage sensor or other measuring instrument.

[0054] It should be noted that in step S1, the hydraulic brake outputs the braking force through the brake pedal signal, and the brake pedal pressure is also one of the parameters used to calculate the magnitude of the motor output reverse torque. The accelerator pedal signal is only used to determine the driver's intention and whether the vehicle is in a driving state. All the above collected parameters are sent to the vehicle controller for data analysis, processing and calculation.

[0055] like Figure 2 As shown, the motor speed is positively correlated with the electric braking force, that is, the higher the current speed, the greater the required electric braking force, and vice versa. When the speed is lower than Vmin, the electric braking function can be withdrawn. In step S2, the electric braking torque required for each wheel is constrained according to the collected speed of each walking motor, and the calculation formula of the speed constraint coefficient is as follows:

[0056]

[0057] Among them, V is the real-time speed of the motor during vehicle driving, Vmax is the maximum speed of the motor under normal working conditions, Vmin is the minimum speed of the electric brake, and k v is the speed constraint coefficient.

[0058] It is also important to note that different motors and motor controllers have different speed ranges, so V min and V max Parameters need to be adjusted according to the actual device.

[0059] like Figure 3As shown, most motor controllers can directly measure their own bus voltage data, and the upper limit of the controller's operating voltage is usually 1.2 to 1.5 times its rated operating voltage. When the motor is reversely braked, braking feedback is generated, which will cause the bus voltage to rise instantly, which is very likely to be higher than the upper limit of the controller's operating voltage, causing irreversible damage to the controller. Therefore, in order to protect the normal operation of the controller, it is necessary to set a voltage coefficient to constrain the motor's reverse torque output. In step S2, the electric braking torque required for each wheel is constrained according to the bus voltage collected from each motor controller. The calculation formula of the bus voltage constraint coefficient is as follows:

[0060]

[0061] Among them, U is the bus voltage of each motor controller, U n is the rated working voltage of the motor controller, Umax is the limit working voltage of the motor controller, k u is the bus voltage constraint coefficient.

[0062] Normally, the pressure of the hydraulic brake circuit is inversely correlated with the hydraulic braking force, that is, as the hydraulic brake pedal gradually decreases from the maximum angle in the initial state, the pressure of the hydraulic brake circuit also gradually decreases, and the hydraulic braking force gradually increases. The depth of the brake pedal reflects the driver's braking intention. The smaller the driver controls the brake pedal opening, the greater the braking force he hopes to obtain, and the braking process will be completed as soon as possible. The brake pedal is located in the hydraulic brake circuit and controls the output braking force of the hydraulic brake system. By adding a pressure sensor or other pressure measurement device to the hydraulic circuit, the pressure of the hydraulic brake circuit can be measured. The reverse torque output by the motor increases as the depth of the driver's control of the brake pedal increases. Therefore, a simple equation can be constructed to obtain the mapping relationship between the hydraulic brake coefficient and the pressure of the hydraulic brake circuit.

[0063] In step S2, the electric braking torque required by each wheel is constrained according to the collected hydraulic brake circuit pressure, and the hydraulic brake coefficient calculation formula is as follows:

[0064]

[0065] Among them, F b is the measured hydraulic brake circuit pressure, F bmax is the maximum pressure of the hydraulic brake circuit, k b is the hydraulic braking coefficient.

[0066] By analyzing the mechanical structure of the shuttle vehicle to which this application applies, the entire vehicle can be divided into three groups, namely the front two wheels, the middle two wheels and the rear two wheels, for braking force analysis. Analyzing the structure of this type of vehicle, it can be seen that the front two wheels are located on the front frame, and the main load is the fixed weight of the front frame. The rear four wheels are located on the rear frame, and the external load is mainly borne by the rear four wheels, while the impact on the force of the front two wheels is small and can be ignored.

[0067] Since the influence of external load on the force of the front two wheels can be ignored, the electric braking torque required by the front two wheels can be considered to be only related to the vehicle speed and the driver's braking intention, and is not affected by the load. The calculation formula of the braking torque of the front two wheels is as follows:

[0068] T 12 =T max *k b *k v *k u

[0069] Among them, T 12 is the electric braking torque required for the front two wheels, T max is the maximum braking torque allowed by the motor, k v is the speed constraint coefficient, k b is the hydraulic braking coefficient, k u is the bus voltage constraint coefficient;

[0070] The external load is considered to be borne by the middle two wheels and the rear two wheels. The electric braking force required by the middle two wheels and the rear two wheels is calculated as follows:

[0071] F 34 =F3*f*k b *(1+1.07*f*k b )

[0072] F 56 =2*F3*f*k b -F 34

[0073] where F 34 is the electric braking force required for the middle two wheels, F 56 is the electric braking force required for the rear two wheels, f is the road friction coefficient, F3 is the bearing pressure of a single intermediate wheel or rear wheel, k b is the hydraulic braking coefficient;

[0074] It should be pointed out that the above formula is the electric braking torque required by the middle two wheels and the rear two wheels when the vehicle is moving forward. When moving backward, the two are opposite, that is,

[0075] F 34 =2*F3*f*k b -F 56

[0076] F 56 =F3*f*k b *[1+1.07*f*k b ]

[0077] Among them, F 34 is the electric braking force required for the middle two wheels, F 56 is the electric braking force required for the rear two wheels, f is the road friction coefficient, F3 is the bearing pressure of a single intermediate wheel or rear wheel, k b is the hydraulic braking coefficient.

[0078] The calculation formula for the electric braking torque required for the middle two wheels and the rear two wheels is:

[0079]

[0080]

[0081] Among them, F 34 is the electric braking force required for the middle two wheels, F 56 is the electric braking force required for the rear two wheels, f is the road friction coefficient, i is the reduction ratio of the tire reducer, k v is the speed constraint coefficient, k u is the bus voltage constraint coefficient; T 34 is the electric braking torque required for the middle two wheels, T 56 The electric braking torque required for the rear two wheels.

[0082] The electric feedback braking is integrated with the hydraulic braking. Due to the limitation of hydraulic characteristics, the braking force in the first part of the hydraulic brake pedal stroke [0, L1] is often very small, and the braking effect is not obvious; while the braking force in the last part of the stroke [L2, 1] is very large, and the tire can often be locked mechanically. Therefore, hydraulic braking plays a greater role in the [L1, 1] interval. In order to make up for the disadvantage of weak hydraulic braking force in the [0, L1] interval, the electric braking force needs to play a role in this interval. In the [0, L1] interval, without considering the influence of bus voltage and vehicle speed, the electric braking force increases with the increase of the brake pedal stroke, and reaches and maintains the maximum value at [L1, 1]. In step S5, in the 0-L1 interval of the brake pedal stroke, the reverse torque output by each travel motor increases with the increase of the brake pedal stroke; in the L1-1 interval of the brake pedal stroke, the reverse torque output by each travel motor reaches and maintains the maximum, and the hydraulic braking force gradually increases.

[0083] In summary, the present application provides an electro-hydraulic multi-system dynamic joint braking system and algorithm for a mining heavy shuttle vehicle. The vehicle controller samples the travel motor speed, vehicle load, accelerator pedal signal, brake pedal signal, controller bus voltage, etc. in real time, and combines the road conditions and other fixed parameters of the vehicle to perform data analysis to obtain the real-time reverse torque required for vehicle braking, which is sent to the travel motor controller to achieve electro-hydraulic multi-system dynamic joint braking. Figure 1 It is a vehicle braking flow chart of the present invention.

[0084] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. An electro-hydraulic multi-system dynamic combined braking algorithm for a heavy-duty shuttle car for mining, characterized by: The following steps are included: S1: Real-time synchronous acquisition of the opening signals of the accelerator pedal and the brake pedal, the pressure signal of the hydraulic brake circuit, the tire load pressure signal, the speed and direction signals of each travel motor, and the bus voltage signal of each travel motor controller; S2: Generate a speed constraint coefficient, a voltage constraint coefficient and a hydraulic brake coefficient respectively according to the collected speed signals of each travel motor, the bus voltage signals of each travel motor controller and the pressure signals of the hydraulic brake circuit; S3: Generates the electric braking force required for braking the front two wheels, the middle two wheels, and the rear two wheels based on the speed constraint coefficient, the hydraulic braking coefficient, the tire load pressure, and the road friction coefficient; S4: Generate the electric braking torque required by each wheel according to the electric braking force required by each wheel, the speed constraint coefficient, the voltage constraint coefficient, the road friction coefficient, and the reduction ratio of the tire reducer; S5: Based on the electric braking torque required for each wheel obtained in S4, within the travel range of the brake pedal of 0-L1, the vehicle controller controls each travel motor to output the corresponding counter-torque to realize electric braking of the vehicle; within the travel range of the brake pedal of L1-1, the vehicle controller controls each travel motor to continuously output the counter-torque, and combines it with the hydraulic braking of the brake pedal to realize the electric-hydraulic combined braking of the vehicle.

2. According to claim 1, a dynamic combined braking algorithm of electro-hydraulic multi-systems for heavy-duty shuttle vehicles for mining, characterized in that: In step S1, a pressure sensor is provided on the hydraulic circuit where the brake pedal is located to measure the pressure signal of the hydraulic brake circuit; the rotation speed of each travel motor is measured by a rotary transformer or an encoder, and the bus voltage of each travel motor controller is measured by a voltage meter.

3. The electro-hydraulic multi-system dynamic combined braking algorithm for a heavy-duty shuttle car for mining according to claim 1 is characterized by: In step S2, the electric braking torque required by each wheel is constrained according to the collected rotation speed of each travel motor, and the speed constraint coefficient is calculated as follows: Among them, V is the real-time speed of the motor during vehicle driving, Vmax is the maximum speed of the motor under normal working conditions, Vmin is the minimum speed of the electric brake, and k v is the speed constraint coefficient.

4. The electro-hydraulic multi-system dynamic combined braking algorithm for a heavy-duty shuttle car for mining according to claim 3 is characterized by: In step S2, the electric braking torque required by each wheel is constrained according to the bus voltage collected from each motor controller, and the calculation formula of the bus voltage constraint coefficient is as follows: Among them, U is the bus voltage of each motor controller, U n is the rated working voltage of the motor controller, Umax is the limit working voltage of the motor controller, k u is the bus voltage constraint coefficient.

5. The electro-hydraulic multi-system dynamic combined braking algorithm for a heavy-duty shuttle car for mining according to claim 4 is characterized by: In step S2, the electric braking torque required by each wheel is constrained according to the collected hydraulic brake circuit pressure, and the hydraulic brake coefficient calculation formula is as follows: Among them, F b is the measured hydraulic brake circuit pressure, F bmax is the maximum pressure of the hydraulic brake circuit, k b is the hydraulic braking coefficient.

6. The electro-hydraulic multi-system dynamic combined braking algorithm for a heavy-duty shuttle car for mining according to claim 5 is characterized by: In the steps S3 and S4, since the influence of the external load on the force of the front two wheels can be ignored, the electric braking torque required by the front two wheels can be considered to be only related to the vehicle speed and the driver's braking intention, and is not affected by the load. The calculation formula of the braking torque of the front two wheels is as follows: T 12 =T max *k b *k v *k u Among them, T 12 is the electric braking torque required for the front two wheels, T max is the maximum braking torque allowed by the motor, k v is the speed constraint coefficient, k b is the hydraulic braking coefficient, k u is the bus voltage constraint coefficient; The external load is considered to be borne by the middle two wheels and the rear two wheels. The electric braking force required by the middle two wheels and the rear two wheels is calculated as follows: F 34 =F3*f*k b *(1+1.07*f*k b ) <h2 style=";text-align:left;direction:ltr">F<h2 style=";text-align:left;direction:ltr"> 56 <h2 style=";text-align:left;direction:ltr"> =2*F3*f*k<h2 style=";text-align:left;direction:ltr"> b <h2 style=";text-align:left;direction:ltr"> -F<h2 style=";text-align:left;direction:ltr"> 34 where F 34 is the electric braking force required for the middle two wheels, F 56 is the electric braking force required for the rear two wheels, f is the road friction coefficient, F3 is the bearing pressure of a single intermediate wheel or rear wheel, k b is the hydraulic braking coefficient; It should be pointed out that the above formula is the electric braking torque required by the middle two wheels and the rear two wheels when the vehicle is moving forward. When moving backward, the two are opposite, that is, <h2 style=";text-align:left;direction:ltr">F<h2 style=";text-align:left;direction:ltr"> 34 <h2 style=";text-align:left;direction:ltr"> =2*F3*f*k<h2 style=";text-align:left;direction:ltr"> b <h2 style=";text-align:left;direction:ltr"> -F<h2 style=";text-align:left;direction:ltr"> 56 F 56 =F3*f*k b *[1+1.07*f*k b ] Among them, F 34 is the electric braking force required for the middle two wheels, F 56 is the electric braking force required for the rear two wheels, f is the road friction coefficient, F3 is the bearing pressure of a single intermediate wheel or rear wheel, k b is the hydraulic braking coefficient.

7. The electro-hydraulic multi-system dynamic combined braking algorithm for a heavy-duty shuttle car for mining according to claim 6 is characterized by: In step S4, the calculation formula for the electric braking torque required by the middle two wheels and the rear two wheels is: Among them, F 34 is the electric braking force required for the middle two wheels, F 56 is the electric braking force required for the rear two wheels, f is the road friction coefficient, i is the reduction ratio of the tire reducer, k v is the speed constraint coefficient, k u is the bus voltage constraint coefficient; T 34 is the electric braking torque required for the middle two wheels, T 56 The electric braking torque required for the rear two wheels.

8. The electro-hydraulic multi-system dynamic combined braking algorithm for a heavy-duty shuttle car for mining according to claim 1 is characterized by: In step S5, within the brake pedal stroke range 0-L1, the counter torque output by each travel motor increases as the brake pedal stroke increases; within the brake pedal stroke range L1-1, the counter torque output by each travel motor reaches and remains maximum, and the hydraulic braking force gradually increases.

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