Rail transit mechanical, electrical and hydraulic combined braking control method and system

Abstract

The scheme relates to the field of rail transit locomotive braking, and discloses a rail transit mechanical, electrical and hydraulic three-stage combined braking control method and a control system. The control method steps are as follows: a power split motor train unit including two or more than two power sources of internal combustion and electricity is used, one or several brakes of mechanical braking, electrical braking and hydraulic braking are selected according to the opening degree of the brake handle on the motor train unit, and the selected brake is used for braking. The control system includes a hydraulic retarder, a traction motor, a traction inverter, a mechanical transmission box, a clutch, an axle gear box, mechanical brake shoes, an energy storage device and a controller. Through the mechanical, electrical and hydraulic three-stage combined braking mode, the risk of braking failure caused by mechanical braking wear is further reduced, and the reliability and comfort of the braking system are improved.

Description

Technical Field

[0001] This invention belongs to the field of rail transit braking, specifically relating to a three-level combined braking control method and system for rail transit involving mechanical, electrical, and hydraulic systems. Background Technology

[0002] Multi-power hybrid EMUs are increasingly being used in railway passenger transport due to their high cost-effectiveness, ability to cross different lines, and low-carbon and green attributes.

[0003] The "Railway Technical Management Regulations" stipulate the emergency braking distances for high-speed trains with different initial speeds on my country's high-speed railways. In other words, these emergency braking distance limits apply to all train types on all current high-speed railway lines in my country, for emergency braking (stopping) distances on both straight and curved sections. Taking the currently commonly used highest speed limits as an example: For high-speed trains with an initial speed of 200 km / h, the emergency braking distance limit is 2000 meters; for 250 km / h, it is 3200 meters; for 300 km / h, it is 3800 meters; and for 350 km / h, it is 6500 meters.

[0004] The braking system of multi-power hybrid electric vehicles, as the component with the highest safety level, prioritizes high reliability and braking comfort. Currently, the independent braking methods used in vehicles include mechanical braking, hydraulic braking, and electric braking.

[0005] Mechanical braking primarily utilizes compressed air to generate braking force, causing the vehicle to slow down or stop. During driving, when the driver presses the brake pedal, compressed air enters the brake system through the brake valve, causing the brake pads to contact the wheels and generate braking force. Long-term mechanical braking causes significant wear and tear on brake components, requiring regular maintenance and replacement, resulting in high maintenance costs.

[0006] Hydraulic braking: Utilizing hydraulic transmission, static fluid within a sealed container can transmit applied pressure equally. In a hydraulic braking system, when the brake pedal is depressed, it pushes the piston of the master cylinder forward, pressurizing the brake fluid within the master cylinder. This pressure is transmitted through the brake lines to the pistons of each brake wheel cylinder, pushing the pistons and brake shoes outward. This causes the brake shoes to make close contact with the brake drum, generating frictional torque, thereby decelerating or stopping the vehicle. Hydraulic braking has drawbacks: it requires more effort to operate, has limited braking torque, is unsuitable for vehicles with heavy loads, and the hydraulic fluid has poor fluidity at low temperatures and is prone to vapor lock at high temperatures. Furthermore, hydraulic braking alone cannot stop trains traveling at speeds below 5 km / h.

[0007] Electric braking: Primarily used on electric locomotives. When braking is required, the train's inertia drives the traction motor, which then functions as a generator, converting the train's kinetic energy into electrical energy and outputting braking current. The counter-torque generated on the traction motor axle acts on the wheelset, creating braking force to decelerate the train or limit its speed on downhill slopes. Electric braking is particularly effective at limiting the speed of high-speed electric locomotives, but it cannot bring electric vehicles to a quick stop, thus limiting its application environment.

[0008] Each of the three braking methods has certain drawbacks when used individually, especially when used in the braking process of hybrid electric vehicles with multiple power sources. How to reduce the risk of brake failure, improve the reliability and comfort of the braking system, and improve energy utilization is an important research direction for the braking of hybrid electric vehicles with multiple power sources. Summary of the Invention

[0009] The purpose of this application is to propose a three-level combined braking control method for rail transit systems, including mechanical, electrical, and hydraulic systems, and a corresponding control system, in order to improve the reliability and comfort of the braking system.

[0010] To achieve the above objectives, this application provides a three-level combined braking control method for rail transit, which calculates the braking force corresponding to the braking signal of the brake control device on the EMU through the controller, and matches one of the following braking methods according to the braking force: mechanical braking, electric braking, or hydraulic braking, or two combined braking or three simultaneous braking.

[0011] The brake actuator is a push rod with a maximum stroke. The push rod's lowest point is defined as 0% opening, and its maximum stroke is defined as 100% opening. During deceleration and braking, the driver typically pushes the push rod between 0% and 100% opening. Based on the driver's brake lever opening, the controller calculates the required braking force using the opening and current speed. It can choose from electric braking, hydraulic braking, and mechanical braking. If one braking method is insufficient, it selects any two methods to ensure complete braking force coverage. If neither method is sufficient, all three methods are applied simultaneously. This flexible braking method selection, with the controller distributing braking force, ensures effective braking.

[0012] The braking method satisfies the following steps:

[0013] S1. The controller acquires the braking signal and calculates the required braking force F under the current braking signal based on the braking force external characteristic curve corresponding to the current vehicle speed. brake ;

[0014] S2. If only one braking method is needed to meet the braking force requirements, the vehicle's braking force output should prioritize electric braking, followed by hydraulic braking, and lastly mechanical braking.

[0015] S3: After the braking signal is issued, the controller first detects and determines whether the energy storage system has a failure to charge; if the energy storage system has not a failure to charge, then proceed to step S4; if the energy storage system has a failure to charge, then proceed directly to step S5.

[0016] S4: The controller obtains the current depth of discharge (SOH) of the energy storage system via the communication cable. The value of SOH ranges from 0-100%, and the current voltage E of the energy storage system is... current The maximum current I of the energy storage system max Wheel speed n wheel And the wheel diameter D, to determine the required braking force F. brake Is it greater than the maximum braking force F that electric braking can provide at the current speed? elec If the braking force provided by the electric brake at the current speed is sufficient to reach the required speed within a specified time, the controller only outputs an electric brake signal, and the braking system only performs electric braking. The execution relationship satisfies: Otherwise, after the controller executes the maximum electric braking force, the excess braking force will be completed by hydraulic braking and / or mechanical braking. If hydraulic braking is required to participate in step S5, mechanical braking is required to participate in step S6.

[0017] S5: The controller calculates the maximum braking force F that the current hydraulic retarder can provide. Hydraulicmax and minimum braking force F Hydraulicmin The F Hydraulicmax =MAX(F Hydraulic )=κ*MAX(F Hydraulic ), where MAX(F) Hydraulic ) represents the maximum braking force of the hydraulic retarder at the current speed, and κ is the hydraulic braking coefficient, the expression for which is shown below:

[0018]

[0019] Among them, T real T represents the real-time temperature of the hydraulic retarder. rate The rated temperature at which the hydraulic retarder can exert its maximum braking force, T max The maximum operating temperature of the hydraulic retarder. If the maximum hydraulic braking force cannot cover the braking force required at the current speed, the excess braking force will be borne by the mechanical brake.

[0020] S6: When the excess braking force needs to be borne by mechanical braking during braking force distribution, the controller will distribute the mechanical braking force evenly to the non-moving shafts; the force applied to each non-moving shaft is F. mech_avg =F mechanical / n drag_axle F mech_avg For the mechanical braking force borne by each non-moving shaft, F mechanical For the mechanical braking force required by mechanical braking, n drag_axle This refers to the number of non-moving axles of the vehicle. Furthermore, the controller also needs to calculate the adhesion force F of the moving axles. adh Determine the electric braking force F elec +Hydraulic braking force F Hydraulic Is it greater than F? adh The judgment process is as follows:

[0021] If F elec +F Hydraulic >F adh Then the controller controls F Hydraulic or F elec weaken, until F elec +F Hydraulic ≤F adh The electric braking force at this time is F elecout The hydraulic braking force is F Hydraulicout The controller outputs electric braking force F elecout and hydraulic braking force F Hydraulicout Feed the moving shaft;

[0022] If F elec +F Hydraulic ≤F adh Then the controller directly outputs the electric braking force F. elecout =F elec and hydraulic braking force F Hydraulicout =F Hydraulic Give the moving shaft.

[0023] The adhesion F adh The calculation formula is: F adh =μ adh *W adh *9.8, where μ adh W is the adhesion coefficient. adh For adhesive weight.

[0024] The braking characteristic curve of the mechanical braking performed in the above steps satisfies:

[0025] Among them, F max V is the maximum braking force of the vehicle's mechanical braking. real V is the current actual speed of the vehicle. InfP For the vehicle to exert maximum braking force Fmax The vehicle speed, V max That is the vehicle's maximum speed.

[0026] When the actual speed of the vehicle is less than the speed at which the maximum braking force is exerted, the vehicle can use full mechanical braking. When the actual speed of the vehicle is between the maximum speed (maximum speed limit) and the speed at which the maximum braking force is exerted, the vehicle selects the ratio of the speed at which the maximum braking force is exerted to the current speed and multiplies it by the maximum braking force of the mechanical brakes. In other words, once the current speed has exceeded the limit of the mechanical brakes, the mechanical brakes will play a partial role. To achieve full braking, it is necessary to combine other braking methods.

[0027] The braking characteristic curve of the electric braking performed by the above steps satisfies:

[0028] F elec_max V is the maximum electric braking force of the vehicle's electric braking system. real V is the current actual speed of the vehicle. InfP_elec The maximum braking force F that the vehicle's motor can exert elec_max The vehicle speed, V max That is the vehicle's maximum speed.

[0029] The braking characteristic curve of the hydraulic braking performed by the above steps satisfies:

[0030]

[0031] Among them, F Hydraulic_max V is the maximum electric braking force of the vehicle's hydraulic braking system. real V is the current actual speed of the vehicle. infP_Hydraulic V is the maximum vehicle speed at which the vehicle's hydraulic brakes can exert the maximum braking force. max V is the vehicle's maximum speed. off V is the minimum vehicle speed at which the minimum hydraulic braking force can be activated. min It is the minimum vehicle speed at which the vehicle's hydraulic brakes can exert maximum braking force.

[0032] Furthermore, when emergency braking is required, the controller determines whether the driver has pressed the emergency stop button; if the emergency stop button is pressed, the controller allocates F... elecout =0,F Hydraulicout =0,F mechanical =F brake F mech_avg =F mechanical / n axle n axle This refers to the total number of axles in the vehicle.

[0033] To achieve the aforementioned three-stage combined mechanical, electrical, and hydraulic braking method, this application provides a control system, including a brake lever, a hydraulic retarder, a traction motor, a traction inverter, a mechanical transmission box, a clutch, an axle gearbox, mechanical brake shoes, an energy storage device, and a controller; the brake lever is connected to the controller for input electrical signals, and the controller converts the brake lever's opening degree into the required braking force.

[0034] The traction motor and the mechanical transmission box are connected by a clutch. The mechanical transmission box is connected to the main drive shaft of the axle. The traction motor is used to implement electric braking force output. The hydraulic retarder is connected to the main drive shaft through gear meshing and is used to receive controller commands to implement hydraulic braking force output.

[0035] The energy storage device is connected to the DC output side of the traction inverter via a cable, and the AC input side of the traction inverter is connected to the traction motor via a cable. The traction inverter receives the electric braking command signal from the controller and controls the traction motor to output the required electric braking force. The controller receives the electric braking force, hydraulic braking force, and mechanical braking force feedback from the traction inverter, hydraulic retarder, and mechanical brake shoes via communication. The controller is used to collect vehicle speed and hydraulic retarder oil temperature, calculate braking deceleration, determine whether slippage occurs, and calculate and distribute braking force. The controller accumulates and calculates braking energy based on the electric braking and hydraulic braking time and the real-time braking force generated.

[0036] The real-time braking force F of the hydraulic braking Hydraulic_real The controller incorporates a preset relationship between pressure, rotational speed, and force. It collects the current rotational speed of the brake rotor and the pressure in the brake chamber, and calculates the current regenerative braking power. The expression for the current regenerative braking power is: P elec_real =E currnt *I current , where P elec_real I is the current regenerative braking power of electric braking. current The charging current of the energy storage device under the current electric braking condition is given by: C = ∫P elec_real dt+∫F Hydraulic_real·vdt .

[0037] The beneficial effects of this invention compared with the prior art are as follows: This method, in conjunction with the control system, adopts different braking strategies under different braking requirements. It employs a flexible multi-braking strategy, integrating mechanical braking, electric braking, and hydraulic braking methods, which greatly enhances the safety of rail vehicles, improves the comfort of the braking process, and also reduces the emergency braking distance of rail vehicles. Attached Figure Description

[0038] Figure 1A logic diagram of the steps involved in the combined mechanical, electrical, and hydraulic braking system for rail transit.

[0039] Figure 2 External characteristic curves for mechanical braking and electric braking;

[0040] Figure 3 This is a curve showing the characteristics of hydraulic braking.

[0041] Figure 4 This is a schematic diagram of a three-level combined braking control system for rail transit, consisting of mechanical, electrical, and hydraulic components. Detailed Implementation

[0042] The reference numerals in the embodiments are listed below: 1. Traction motor, 2. Clutch, 3. Mechanical brake shoe, 4. Energy storage device, 5. Traction inverter, 6. Hydraulic retarder, 7. Axle gearbox, 8. Wheelset.

[0043] Example 1:

[0044] Applications include distributed power EMUs with electric power, with a maximum speed limit of 200 km / h, such as... Figure 1 , Figure 2 and Figure 3 As shown, the three-level combined braking control method of rail transit (mechanical, electrical, and hydraulic) calculates the braking force corresponding to the braking signal of the brake control device on the EMU through the controller, and matches one of the braking forces, namely mechanical braking, electric braking, or hydraulic braking, or two combined braking or three simultaneous braking, according to the braking force.

[0045] The brake actuator is a push rod with a maximum stroke. The push rod's lowest point is defined as 0% opening, and its maximum stroke is defined as 100% opening. During deceleration and braking, the driver typically pushes the push rod between 0% and 100% opening. Based on the driver's brake lever opening, the controller calculates the required braking force using the opening and current speed. It can choose from electric braking, hydraulic braking, and mechanical braking. If one braking method is insufficient, it selects any two methods to ensure complete braking force coverage. If neither method is sufficient, all three methods are applied simultaneously. This flexible braking method selection, with the controller distributing braking force, ensures effective braking.

[0046] like Figure 1 As shown, the braking method satisfies the following steps:

[0047] S1. The controller acquires the braking signal and calculates the required braking force F under the current braking signal based on the braking force external characteristic curve corresponding to the current vehicle speed. brake ;

[0048] S2. If only one braking method is needed to meet the braking force requirements, the vehicle's braking force output should prioritize electric braking, followed by hydraulic braking, and lastly mechanical braking.

[0049] S3: After the braking signal is issued, the controller first detects and determines whether the energy storage system has a failure to charge; if the energy storage system has not a failure to charge, then proceed to step S4; if the energy storage system has a failure to charge, then proceed directly to step S5.

[0050] S4: The controller obtains the current depth of discharge (SOH) of the energy storage system via the communication cable. The value of SOH ranges from 0-100%, and the current voltage E of the energy storage system is... current The maximum current I of the energy storage system max Wheel speed n wheel And the wheel diameter D, to determine the required braking force F. brake Is it greater than the maximum braking force F that electric braking can provide at the current speed? elec If the braking force provided by the electric brake at the current speed is sufficient to reach the required speed within a specified time, the controller only outputs an electric brake signal, and the braking system only performs electric braking. The execution relationship satisfies: Otherwise, after the controller executes the maximum electric braking force, the excess braking force will be completed by hydraulic braking and / or mechanical braking. If hydraulic braking is required to participate in step S5, mechanical braking is required to participate in step S6.

[0051] S5: The controller calculates the maximum braking force F that the current hydraulic retarder can provide. Hydraulicmax and minimum braking force F Hydraulicmin The F Hydraulicmax =MAX(F Hydraulic )=κ*MAX(F Hydraulic ), where MAX(F) Hydraulic ) represents the maximum braking force of the hydraulic retarder at the current speed, and κ is the hydraulic braking coefficient, the expression for which is shown below:

[0052]

[0053] Among them, T real T represents the real-time temperature of the hydraulic retarder. rate The rated temperature at which the hydraulic retarder can exert its maximum braking force, T max The maximum operating temperature of the hydraulic retarder; if the maximum hydraulic braking force cannot cover the braking required at the current speed.

[0054] The force will be used to meet the excess braking force demand through mechanical braking;

[0055] S6: When the excess braking force needs to be borne by mechanical braking during braking force distribution, the controller will distribute the mechanical braking force evenly to the non-moving shafts; the force applied to each non-moving shaft is F. mech_avg =F mechanical / n drag_axle F mech_avg For the mechanical braking force borne by each non-moving shaft, F mechanical For the mechanical braking force required by mechanical braking, n drag_axle This refers to the number of non-moving axles of the vehicle. Furthermore, the controller also needs to calculate the adhesion force F of the moving axles. adh Determine the electric braking force F elec +Hydraulic braking force F Hydraulic Is it greater than F? adh The judgment process is as follows:

[0056] If F elec +F Hydraulic >F adh Then the controller controls F Hydraulic or F elec weaken, until F elec +F Hydraulic ≤F adh The electric braking force at this time is F elecout The hydraulic braking force is F Hydraulicout The controller outputs electric braking force F elecout and hydraulic braking force F Hydraulicout Feed the moving shaft;

[0057] If F elec +F Hydraulic ≤F adh Then the controller directly outputs the electric braking force F. elecout =F elec and hydraulic braking force

[0058] F Hydraulicout =F Hydraulic Give the moving shaft.

[0059] The adhesion F adh The calculation formula is: F adh =μ adh *W adh *9.8, where μ adh W is the adhesion coefficient. adh For adhesive weight.

[0060] like Figure 2 As shown, the braking characteristic curve MAX(F) of the mechanical braking performed in the above steps is... currentspeed )satisfy:

[0061] Among them, F maxV is the maximum braking force of the vehicle's mechanical braking. real V is the current actual speed of the vehicle. InfP For the vehicle to exert maximum braking force F max The vehicle speed, V max That is the vehicle's maximum speed.

[0062] When the actual speed of the vehicle is less than the speed at which the maximum braking force is exerted, the vehicle can use full mechanical braking. When the actual speed of the vehicle is between the maximum speed (maximum speed limit) and the speed at which the maximum braking force is exerted, the vehicle selects the ratio of the speed at which the maximum braking force is exerted to the current speed and multiplies it by the maximum braking force of the mechanical brakes. In other words, once the current speed has exceeded the limit of the mechanical brakes, the mechanical brakes will play a partial role. To achieve full braking, it is necessary to combine other braking methods.

[0063] like Figure 2 As shown, the curve MAX(F) elec The electric braking characteristic curve satisfies:

[0064] F elec_max V is the maximum electric braking force of the vehicle's electric braking system. real V is the current actual speed of the vehicle. InfP_elec The maximum braking force F that the vehicle's motor can exert elec_max The vehicle speed, V max That is the vehicle's maximum speed.

[0065] like Figure 3 As shown, the curve MAX(F) Hydraulic The curve represents the hydraulic braking characteristic curve, which satisfies the following:

[0066]

[0067] Among them, F Hydraulic_max V is the maximum electric braking force of the vehicle's hydraulic braking system. real V is the current actual speed of the vehicle. infP_Hydraulic V is the maximum vehicle speed at which the vehicle's hydraulic brakes can exert the maximum braking force. max V is the vehicle's maximum speed. off V is the minimum vehicle speed at which the minimum hydraulic braking force can be activated. min It is the minimum vehicle speed at which the vehicle's hydraulic brakes can exert maximum braking force.

[0068] If it is a single braking action, the braking threshold range in this embodiment is selected as: mechanical braking vehicle speed threshold of 0 to V. max The speed threshold for electric braking vehicles is 5 km / h. max The speed threshold for hydraulically braked vehicles is V.off -V max .

[0069] Braking threshold range for any combination of two braking methods: Vehicle speed threshold for combination of mechanical braking and electric braking 5 km / hV max The speed threshold V of a vehicle combining mechanical and hydraulic braking off -V max The speed threshold V of a vehicle combining electric braking and hydraulic braking off -V max Three simultaneous braking threshold ranges: V off -V max .

[0070] Based on the patterns under several braking curves, such as Figure 1 As shown, the three-stage combined braking method of rail transit (mechanical, electrical, and hydraulic) satisfies the following steps: S1: When a signal indicating a change in the driver's brake lever opening is received, the controller collects the driver's brake lever opening and calculates the required braking force F at the current lever opening based on the braking force external characteristic curve corresponding to the current vehicle speed. brake .

[0071] F brake =MAX(F currentspeed )*Brk norch In the formula, F brake MAX(F) is the braking force required at the current extreme position of the handle. currentspeed ) is the maximum braking force that satisfies the vehicle's braking curve at the current engine speed. norch This represents the current extreme position of the handle, with a value range of 0-100%. When the value is 100%, F... brake =MAX(F currentspeed ).

[0072] S2: The priority of vehicle braking force output is electric braking first, followed by hydraulic braking, and finally mechanical braking.

[0073] S3: The controller detects and determines whether the energy storage system has experienced a charging failure. If the energy storage system has experienced a charging failure, step S4 is executed; if the energy storage system has not experienced a charging failure, step S5 is executed.

[0074] S4: The controller obtains the current depth of discharge (SOH) of the energy storage system via the communication cable. The value of SOH ranges from 0-100%, and the current voltage E of the energy storage system is... current The maximum current I of the energy storage system max Wheel speed n wheel And the wheel diameter D, to determine the required braking force F. brakeIs it greater than the maximum braking force F that electric braking can provide at the current speed? elec .in And F elec ≤MAX(F elec ).

[0075] If F elec Greater than F brake Then proceed to step S7; if the F elec Less than F brake Then proceed to step S5.

[0076] S5: The controller calculates the maximum braking force F that the current hydraulic retarder can provide. Hydraulicmax and minimum braking force F Hydraulicmin F Hydraulicmax =MAX(F Hydraulic )=κ*MAX(F Hydraulic ), where MAX(F) Hydraulic ) represents the maximum braking force of the hydraulic retarder at the current speed, and κ is the hydraulic braking coefficient, the expression for which is shown below: Among them, T real T represents the real-time temperature of the hydraulic retarder. rate The rated temperature at which the hydraulic retarder can exert its maximum braking force, T max This is the maximum operating temperature of the hydraulic retarder.

[0077] For example, the rated operating temperature T of a hydraulic brake rate The temperature is 120℃, T max The temperature is 130℃. Therefore, the current temperature is ≤120℃, κ=1, F Hydraulicmax =MAX(F Hydraulic If the current temperature is 125℃, F Hydraulicmax =0.5×MAX(F) Hydraulic If the current temperature is 131℃, F Hydraulicmax =0, hydraulic automatic failure.

[0078] If F Hydraulic >F brake -F elec The controller then controls the hydraulic retarder to provide F Hydraulic =F brake -F elec Braking force.

[0079] If F Hydraulicmax ≤F brake -F elec The controller then controls the hydraulic retarder to provide F Hydraulic =F Hydraulicmax Braking force.

[0080] If F Hydraulicmin >F brake -F elec The controller then controls the hydraulic retarder to provide F Hydraulic =0 braking force.

[0081] S6: The controller applies mechanical braking to cover braking forces that cannot be covered by electric and hydraulic braking. mechanical =F brake -F elec -F Hydraulic .

[0082] S7: The controller needs to calculate the adhesion force F of the vehicle's moving axle. adh =μ adh *W adh *9.8. Where μ adh W is the adhesion coefficient, which is determined by the relationship between the wheel and rail tread surfaces. adh The adhesive weight is the weight applied to the moving axle (the moving axle refers to the axle that can provide traction power).

[0083] S8: The controller determines the electric braking force F elec +Hydraulic braking force F Hydraulic Is it greater than F? adh ;

[0084] If F elec +F Hydraulic >F adh Then the controller controls F Hydraulic or F elec weaken, until F elec +F Hydraulic ≤F adh The electric braking force at this time is F elecout The hydraulic braking force is F Hydraulicout The controller outputs electric braking force F elecout and hydraulic braking force F Hydraulicout Feed the moving shaft;

[0085] If F elec +F Hydraulic ≤F adh Then the controller directly outputs the electric braking force F. elecout =F elec and hydraulic braking force F Hydraulicout =F Hydraulic Give the moving shaft.

[0086] S9: The controller distributes the mechanical braking force evenly to the non-moving shaft; F mechanical =F brake -F elecout -F HydraulicoutThe force applied to each non-moving shaft is F. mech_avg =F mechanical / n drag_axle n drag_axle This refers to the number of non-driving axles of the vehicle.

[0087] S10: The controller determines whether the driver has pressed the emergency stop button. If the emergency stop button is pressed, the controller assigns F... elecout =0,F Hydraulicout =0,F mechanical =F brake F mech_avg =F mechanical / n axle n axle This refers to the total number of axles in the vehicle.

[0088] Example 2:

[0089] like Figure 4 The illustrated rail transit three-level combined braking control system (mechanical, electrical, and hydraulic) includes a brake lever, a hydraulic retarder 6, a traction motor 1, a traction inverter 5, a mechanical transmission box, a clutch 2, an axle gearbox 7, mechanical brake shoes 3, an energy storage device 4, and a controller. The traction motor 1 and the mechanical transmission box are connected via a clutch 2, which is also connected to the main drive shaft of the axle for implementing electric braking force output. Alternatively, a coupling or gear connection can be used to replace the clutch.

[0090] The brake lever is connected to the controller input electrical signal, and the controller converts the brake lever's opening degree into the required braking force.

[0091] The hydraulic retarder 6 is connected to the main drive shaft via the axle gearbox 7. It is used to receive controller commands and implement hydraulic braking force output, and is arranged in parallel with the traction motor. The mechanical brake shoes 3 are installed on the connecting shaft of the wheelset. The mechanical brake shoes play the roles of braking, speed regulation and protection, ensuring the safe operation of the equipment and the smooth operation of the work.

[0092] The energy storage device 4 is connected to the DC output side of the traction inverter 5 via a cable, and the AC input side of the traction inverter 5 is connected to the traction motor 1 via a cable. The traction inverter 5 receives the electric braking command signal from the controller and controls the traction motor 1 to output the required electric braking force. The controller receives the electric braking force, hydraulic braking force, and mechanical braking force feedback from the traction inverter 5, the hydraulic retarder 6, and the mechanical brake shoe 3 via communication. The controller can collect vehicle speed and hydraulic retarder 6 oil temperature, calculate braking deceleration, determine whether slippage occurs, and calculate and distribute braking force.

[0093] The controller can calculate the braking energy by accumulating the braking time and real-time braking force generated by electric braking and hydraulic braking. The real-time braking force F of the hydraulic braking is included.Hydraulic_real To pre-calibrate the relationship between pressure, speed, and force, the controller collects the current speed of the brake rotor and the pressure in the brake chamber for calculation; the relationship is shown as follows: P elec_real =E currnt *I current , where P elec_real I is the current regenerative braking power of electric braking. current The charging current of the energy storage device under the current electric braking condition; the total energy recovered by braking is C=∫P elec_real dt+∫F Hydraulic_real .vdt.

Claims

1. A three-level combined braking control method for rail transit, characterized by: Based on the braking signal from the brake control device on the EMU, the controller calculates the braking force corresponding to the corresponding braking signal and matches it with one of the following braking methods: mechanical braking, electric braking, or hydraulic braking, or a combination of two or three braking methods. The braking method satisfies the following steps: S1. The controller acquires the braking signal and calculates the required braking force under the current braking signal based on the braking force external characteristic curve corresponding to the current vehicle speed. ; S2. If only one braking method is needed to meet the braking force requirements, the vehicle's braking force output should prioritize electric braking, followed by hydraulic braking, and lastly mechanical braking. S3: After the braking signal is issued, the controller first detects and determines whether the energy storage system has a failure to charge; if the energy storage system has not a failure to charge, then proceed to step S4; if the energy storage system has a failure to charge, then proceed directly to step S5. S4: The controller obtains the current depth of discharge (SOH) of the energy storage system via the communication cable. The value of SOH ranges from 0-100%, and the current voltage of the energy storage system is... The maximum current of the energy storage system Wheel speed And the wheel diameter D, to determine the required braking force. Is it greater than the maximum braking force that electric braking can provide at the current speed? If the braking force provided by the electric brake at the current speed is sufficient to reach the required speed within a specified time, the controller only outputs an electric brake signal, and the braking system only performs electric braking. The execution relationship satisfies: Otherwise, after the controller executes the maximum electric braking force, the excess braking force will be completed by hydraulic braking and / or mechanical braking. If hydraulic braking is required to participate in step S5, mechanical braking is required to participate in step S6. S5: The controller calculates the maximum braking force that the current hydraulic retarder can provide. and minimum braking force The = ,in This represents the maximum braking force of the hydraulic retarder at the current rotational speed. The hydraulic braking coefficient is expressed as follows: , if , in, Real-time temperature of the hydraulic retarder. The rated temperature at which the hydraulic retarder can exert its maximum braking force. The maximum operating temperature of the hydraulic retarder. If the maximum hydraulic braking force cannot cover the braking force required at the current speed, the excess braking force will be borne by the mechanical brake. S6: When the excess braking force needs to be borne by mechanical braking during braking force distribution, the controller will distribute the mechanical braking force evenly to the non-moving shafts; the force applied to each non-moving shaft is... F mech_avg For the mechanical braking force borne by each non-moving shaft, F mechanical The mechanical braking force required for mechanical braking. This refers to the number of non-driving axles of the vehicle. The controller also needs to calculate the adhesion of the vehicle's driving axle. Determine the electric braking force +Hydraulic braking force Is it greater than The judgment process is as follows: like Then the controller controls or weaken, until The electric braking force at this time is The hydraulic braking force is The controller outputs electric braking force. and hydraulic braking force Feed the moving shaft; like The controller then directly outputs electric braking force. and hydraulic braking force Give the moving shaft.

2. The three-level combined braking control method for rail transit (mechanical, electrical, and hydraulic) according to claim 1, characterized in that: The adhesion The calculation formula is: ,in The viscosity coefficient is 1. For adhesive weight.

3. The three-level combined braking control method for rail transit (mechanical, electrical, and hydraulic) according to claim 2, characterized in that: The mechanical braking characteristic curve satisfies: ,in, This is the maximum braking force of the vehicle's mechanical braking system. This is the current actual speed of the vehicle. To maximize the braking force of the vehicle vehicle speed, That is the vehicle's maximum speed.

4. The three-level combined braking control method for rail transit (mechanical, electrical, and hydraulic) according to claim 3, characterized in that: The electric braking characteristic curve satisfies: , This is the maximum electric braking force of the vehicle's electric braking system. This is the current actual speed of the vehicle. To maximize the braking force that the vehicle's motor can exert vehicle speed, That is the vehicle's maximum speed.

5. The three-level combined braking control method for rail transit (mechanical, electrical, and hydraulic) according to claim 4, characterized in that: The hydraulic braking characteristic curve satisfies: ， in, This is the maximum electric braking force of the vehicle's hydraulic braking system. This is the current actual speed of the vehicle. The maximum vehicle speed at which the vehicle's hydraulic brakes can exert the maximum braking force. It is the vehicle's maximum speed. The vehicle is capable of engaging the minimum hydraulic braking force. Minimum vehicle speed, It is the minimum vehicle speed at which the vehicle's hydraulic brakes can exert maximum braking force; the vehicle speed is below... The hydraulic brake is then deactivated.

6. The three-level combined braking control method for rail transit (mechanical, electrical, and hydraulic) according to claim 5, characterized in that: When emergency braking is required, the controller determines whether the driver has pressed the emergency stop button; if the emergency stop button is pressed, the controller allocates... =0, =0, = , , This refers to the total number of axles in the vehicle.

7. A control system for combined mechanical, electrical, and hydraulic braking of rail transit systems, used to execute the control method as described in any one of claims 1 to 6, characterized in that, The control system includes a brake lever, a hydraulic retarder, a traction motor, a traction inverter, a mechanical transmission box, a clutch, an axle gearbox, mechanical brake shoes, an energy storage device, and a controller; the brake lever is connected to the controller for input electrical signals, and the controller converts the brake lever's opening degree into the required braking force. The traction motor and the mechanical transmission box are connected via a clutch. The mechanical transmission box is connected to the main drive shaft of the axle. The traction motor is used to implement electric braking force output. The hydraulic retarder is connected to the main drive shaft via gear meshing and is used to receive controller commands to implement hydraulic braking force output. The energy storage device is connected to the DC output side of the traction inverter via a cable, and the AC input side of the traction inverter is connected to the traction motor via a cable. The traction inverter receives electric braking command signals from the controller and controls the traction motor to output the required electric braking force. The controller receives electric braking force, hydraulic braking force, and mechanical braking force signals from the traction inverter, hydraulic retarder, and mechanical brake shoes via communication. The controller is used to collect vehicle speed and hydraulic retarder oil temperature, calculate braking deceleration, determine whether slippage occurs, and calculate and distribute braking force. The controller adjusts the braking strategy in real time based on the electric braking and hydraulic braking time and the generation of real-time braking force.

8. The control system for the combined mechanical, electrical, and hydraulic braking of rail transit according to claim 7, characterized in that: The real-time braking force of the hydraulic brake The controller incorporates a preset relationship between pressure, rotational speed, and force. It acquires the current rotational speed of the brake rotor and the pressure in the brake chamber, and calculates the current regenerative braking power. The expression for the current regenerative braking power is: ,in This represents the current regenerative braking power of the electric braking system. The charging current of the energy storage device under the current electric braking condition, and the total energy recovered by braking: .

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