Urban rail vehicle pantograph air spring alarm system and control method thereof

Abstract

The present invention discloses an urban rail vehicle pantograph air spring alarm system and a control method thereof, the system comprises: a chassis, an air spring, a pantograph assembly, a sensor assembly, a control unit and an alarm device; the air spring is mounted on the chassis, the bottom of the pantograph assembly is connected to the chassis and the air spring respectively, as the air spring is inflated and exhausted, the pantograph assembly completes the corresponding pantograph raising and lowering actions; the sensor assembly is arranged on the air spring, for monitoring the internal gas pressure data of the air spring and the position change of the air spring during the inflating and exhausting process, and transmitting the data to the control unit, the alarm device is connected to the control unit, for receiving the control command sent by the control unit, and alarming. The present invention has the advantages of compact structure, high control accuracy, high intelligence, etc., can monitor the working state of the air spring in real time, improve the troubleshooting rate, and reduce the urban rail vehicle operation risk caused by the deterioration of the air spring performance.

Description

Technical Field

[0001] The invention belongs to the technical field of urban rail vehicles, and in particular relates to an urban rail vehicle pantograph air spring alarm system and a control method thereof. Background Art

[0002] Currently, most urban rail transit vehicles use airbag pantographs to obtain electrical energy, in which the pantograph's raising and lowering functions are mainly achieved by the inflation and exhaust of air springs. The excellent performance of the air spring has a direct correlation with the pantograph's raising and power-collecting process and the exhaust and lowering process.

[0003] Pantograph air springs are mostly multi-curved bladders, with the main structure made of rubber and curtains. Since pantograph air springs are often located on the roof pantograph chassis, they are greatly affected by the environment during use, and the pantograph air springs will show deterioration trends such as aging and fatigue. When the product deteriorates, the working stroke of the pantograph air spring will change during the pantograph raising process; in the original inflation control system, if the contact pressure between the pantograph and the net is to remain unchanged, the inflation pressure needs to be increased, which increases the inflation stroke of the pantograph air spring and causes the air spring to be in an overcharged state. During the pantograph lowering process, if the air spring product deteriorates, during the exhaust process, the air spring contraction movement cannot effectively reduce the pantograph to the design value, which directly affects the operational safety of the train. In the actual operation of urban rail vehicles, the deterioration process of the pantograph air spring is slow and difficult to track in real time. The existing treatment methods are mostly to find major faults such as rupture and leakage in the air spring, causing the vehicle to be delayed or stopped, and then carry out manual maintenance and replacement, resulting in large losses. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a pantograph air spring alarm system for urban rail vehicles with a compact structure, high control accuracy and high intelligence, and a control method thereof.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] An urban rail vehicle pantograph air spring alarm system comprises a chassis, an air spring, a pantograph assembly, a sensor assembly, a control unit and an alarm device; the air spring is mounted on the chassis, the bottom of the pantograph assembly is respectively connected to the chassis and the air spring, and as the air spring is inflated and exhausted, the pantograph assembly completes corresponding pantograph raising and lowering actions; the sensor assembly is connected to the air spring to monitor the internal gas pressure of the air spring, and the displacement change and tilt angle change of the air spring during the inflating and exhausting process, and transmits the monitoring data to the control unit; the alarm device is connected to the control unit to receive control instructions sent by the control unit and to give an alarm.

[0007] As a further improvement of the present invention, the sensor assembly includes an inclination sensor, and a connecting rod is provided at the moving end of the air spring; the inclination sensor is arranged at the center position of the connecting rod at the moving end of the air spring, and is used to monitor the change in the inclination angle of the air spring during the inflation and deflation process.

[0008] As a further improvement of the present invention, the sensor assembly further includes a displacement sensor, which is disposed on a connecting rod at a moving end of the air spring and is used to monitor displacement changes of the air spring during the inflation and deflation process.

[0009] As a further improvement of the present invention, the sensor assembly also includes a pressure sensor, and the fixed end of the air spring is provided with an air inlet, which is connected to the air circuit system; the pressure sensor is arranged at the air inlet of the air spring to monitor the internal gas pressure of the air spring.

[0010] As a further improvement of the present invention, the pantograph assembly includes: a lower arm, a pull rod, an upper arm and a bow head, the bottom of the lower arm is connected to the moving end of the air spring, the bottom of the pull rod is connected to the end of the base frame, the top of the lower arm and the top of the pull rod are both connected to the bottom of the upper arm, and the top of the upper arm is connected to the bow head; as the air spring is inflated and exhausted, the lower arm moves with the moving end of the air spring to enable the upper arm to raise or lower the bow head.

[0011] As a further improvement of the present invention, it also includes a supporting insulating base, the bottom of the supporting insulating base is fixedly connected to the top of the urban rail vehicle, and the top of the supporting insulating base is fixedly connected to the bottom of the base frame.

[0012] As a general technical concept, the present invention also provides a control method for the above-mentioned urban rail vehicle pantograph air spring alarm system, comprising the following steps:

[0013] S1. Inflate or exhaust the air spring to achieve contact or disconnection between the pantograph assembly and the contact network, monitor the internal gas pressure of the air spring and the position change of the air spring during the inflation and exhaust process in real time through the sensor assembly, and transmit the monitoring data to the control unit;

[0014] S2. constructing a pressure-displacement correlation standard model when the air spring works normally and a pressure-displacement correlation fault diagnosis model when a fault occurs in the control unit, and determining a boundary value of the pressure-displacement correlation fault diagnosis model;

[0015] S3. The control unit constructs a pressure-displacement correlation model of the air spring in the actual working process based on the pressure signal and displacement signal angle signal of the air spring collected in real time by the sensor component, compares the pressure-displacement value with the value of the pressure-displacement correlation fault diagnosis model, and sends corresponding control instructions to the alarm device according to the comparison result.

[0016] As a further improvement of the present invention, in step S1, the sensor assembly includes a pressure sensor, a displacement sensor and an inclination sensor; the internal pressure value of the air spring is monitored in real time by the pressure sensor, and the data signal is transmitted to the control unit; the displacement transformation of the moving end of the air spring during the inflation or exhaust process is monitored in real time by the displacement sensor, and the data signal is transmitted to the control unit; the angle data of the moving end of the air spring during the inflation or exhaust process is monitored in real time by the inclination sensor, and the data signal is transmitted to the control unit.

[0017] As a further improvement of the present invention, the step S2 further comprises:

[0018] Step S2.1, combining the internal pressure (P)-load (W) test standard of the air spring when it leaves the factory and the effective action area Aq of the air spring, use formula (1) to calculate the relationship between the thrust function (F) and the internal pressure (P1);

[0019] F=(P1-P0)Aq (1)

[0020] Among them, F is the thrust function, P1 is the internal pressure of the air spring, and P0 is the standard atmospheric pressure;

[0021] Step S2.2, calculating the minimum kinetic energy (Emin) and maximum kinetic energy value (Emax) required for the air spring to overcome the relevant resistance during the pantograph raising process;

[0022] Emin≤E≤Emax (2)

[0023] E=f(F,S,t) (3)

[0024] Among them, E is the kinetic energy of the air spring, F is the thrust function, S is the displacement value, and t is the working time of the air spring;

[0025] Step S2.3, combining the pantograph raising time limit (T), and then calculating the internal pressure (P1) variation range and the corresponding displacement (S) variation relationship during the working process of the air spring, and constructing the pressure-displacement correlation standard model when the air spring is working normally, as shown in formula (4);

[0026] S=f(E,P1,t) (4)

[0027] Step S2.4, combining the correction and verification results of multiple sets of vehicle assembly data, construct a pressure-displacement correlation fault diagnosis model when the air spring fails, and design the boundary values ​​of the internal pressure and displacement changes under the corresponding fault state.

[0028] As a further improvement of the present invention, the step S3 also includes: the control unit compares the real-time tilt angle with the preset tilt angle based on the tilt angle signal of the air spring collected in real time by the tilt sensor, and sends a corresponding control instruction to the alarm device according to the comparison result.

[0029] Compared with the prior art, the advantages of the present invention are:

[0030] The urban rail vehicle pantograph air spring alarm system and control method thereof of the present invention are designed with a displacement sensor and an inclination sensor that move with the air spring at the moving end of the air spring, and a pressure sensor is set at the inflation inlet of the fixed end of the air spring, and all sensor signals are summarized in the control unit. The control unit constructs a pressure-displacement correlation standard model during the normal operation of the air spring according to the collected pressure and displacement signals, and determines the air spring fault model through the correction and verification of multiple assembly data. Then, the correlation change between the pressure and the displacement of the air spring during the filling and exhaust process of the air spring is monitored in real time, and it is calculated and judged whether the structural performance of the air spring has been irreversibly damaged, and the command control alarm device (indicator light) is used to indicate; or, the control unit compares the real-time tilt angle with the preset tilt angle according to the collected real-time tilt angle signal, and according to the comparison result, the command control alarm device (indicator light) is used to indicate, and the maintenance personnel are accurately reminded to perform maintenance operations on the air spring. The safety risk of urban rail vehicle pantograph operation caused by the deterioration of air spring performance is reduced, and human labor and time costs are saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a schematic diagram of the structural principle of the pantograph air spring alarm system for urban rail vehicles.

[0032] Figure 2 It is a schematic diagram of the partial structural principle of the pantograph air spring alarm system for urban rail vehicles of the present invention.

[0033] Figure 3 This is a control principle diagram of the pantograph air spring alarm system for urban rail vehicles of the present invention.

[0034] Figure 4 It is a schematic diagram of the correlation between the internal pressure P1 and the displacement S of the air spring in the present invention.

[0035] Legend: 1. Support insulating seat; 2. Base frame; 3. Air spring; 4. Lower arm; 5. Pull rod; 6. Upper arm; 7. Bow head; 8. Sensor; 8a. Pressure sensor; 8b. Displacement sensor; 8c. Inclination sensor; 9. Control unit; 10. Alarm device; 11. Connecting rod. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0037] Example

[0038] like Figures 1 to 4 As shown, the pantograph air spring alarm system for urban rail vehicles of the present invention comprises: a chassis 2, an air spring 3, a pantograph assembly, a sensor assembly 8, a control unit 9 and an alarm device 10. The air spring 3 is mounted on the chassis 2, and the bottom of the pantograph assembly is respectively connected to the chassis 2 and the air spring 3, and the air spring 3 is connected to the air circuit system through a pipeline. As the air spring 3 is inflated and exhausted, the pantograph assembly completes the corresponding pantograph raising and lowering actions. The sensor assembly 8 is connected to the air spring 3 to monitor the internal gas pressure data of the air spring 3, as well as the displacement change and tilt angle change of the air spring 3 during the inflation and exhaust process, and transmit the data to the control unit 9. The alarm device 10 is connected to the control unit 9 to receive the control command sent by the control unit 9 and to alarm. Furthermore, in this embodiment, the alarm device 10 can adopt an indicator light display device, which is easy to install and has an obvious warning effect.

[0039] like Figure 2As shown, in this embodiment, the sensor assembly 8 includes a pressure sensor 8a, a displacement sensor 8b and an inclination sensor 8c. The fixed end of the air spring 3 is provided with an air inlet, which is connected to the air circuit system for inflating the air spring 3. The pressure sensor 8a is arranged at the air inlet of the fixed end of the air spring 3, and can directly and accurately measure the internal pressure value of the air spring 3, so that the inflation and exhaust efficiency of the air circuit system is higher. The moving end of the air spring 3 is provided with a connecting rod 11, and the displacement sensor 8b is arranged on the connecting rod 11 and close to the end of the air spring 3, which is used to monitor the movement displacement of the air spring 3 during the inflation and exhaust process; the movement direction during inflation is positive forward, and the movement direction during exhaust is negative backward. The inclination sensor 8c is arranged at the center position of the connecting rod 11 at the moving end of the air spring 3, and is used to monitor the change of the tilt angle of the air spring 3 during the inflation and exhaust process. The air spring used for the pantograph often changes in the stretched length in the horizontal direction, and the displacement sensor 8b and the inclination sensor 8c will move accordingly, and the reliability requirements during installation and application are high. Since the air spring used in the pantograph has no auxiliary spring to provide auxiliary thrust function, the air spring is prone to tilt in the horizontal direction, which will seriously affect the effect of the horizontal thrust function. Setting an inclination sensor 8c can grasp the tilt of the air spring in the horizontal direction in real time.

[0040] It can be understood that under normal circumstances, when the air spring 3 is placed horizontally, it is fixed with fixed rods and ropes in the up and down directions and the horizontal direction, and the angle of the air spring 3 is also centered. Only when the structure of the air spring 3 changes, the connection structure becomes loose. The change in internal pressure at this time will cause the inclination sensor 8c to measure a change in the inclination angle. If the inclination angle change exceeds the set range value, it means that maintenance is required.

[0041] In this embodiment, a pressure sensor 8a is provided at the air inlet of the fixed end of the air spring 3, and a displacement sensor 8b and an inclination sensor 8c are provided at the moving end of the air spring 3. The original air spring fault inspection and repair method is replaced by the cooperation of multiple sensors and a control system, thereby realizing an intelligent fault alarm of the air spring and improving the efficiency of the pantograph height control.

[0042] like Figure 1As shown, in this embodiment, the pantograph assembly includes: a lower arm 4, a pull rod 5, an upper arm 6 and a bow head 7. The bottom of the lower arm 4 is connected to the connecting rod 11 of the moving end of the air spring 3, the bottom of the pull rod 5 is connected to the end of the base frame 2, and the pull rod 5 is away from the fixed end of the air spring 3. The top of the lower arm 4 and the top of the pull rod 5 are both connected to the bottom of the upper arm 6, and there is a certain distance between the top of the lower arm 4 and the top of the pull rod 5 to improve the support stability of the upper arm 6; the top of the upper arm 6 is connected to the bow head 7, and the bow head 7 is in contact with the contact network. As the air spring 3 is inflated and exhausted, the connecting rod 11 pushes the lower arm 4 to move, so that the upper arm 6 can raise or lower the bow head 7.

[0043] like Figure 1 As shown, in this embodiment, three supporting insulating bases 1 are also included, and the bottoms of the three supporting insulating bases 1 are all fixedly connected to the top of the urban rail vehicle (not shown in the figure), and the top of the supporting insulating base 1 is fixedly connected to the bottom of the base frame 2.

[0044] This embodiment also provides a control method based on the above-mentioned urban rail vehicle pantograph air spring alarm system, and its control principle is as follows: Figure 3 As shown, it mainly includes the following steps:

[0045] S1. Inflate or exhaust the air spring 3 to achieve contact or disconnection between the pantograph assembly and the contact network. The internal gas pressure of the air spring 3 and the position change of the air spring 3 during the inflation and exhaust process are monitored in real time by the sensor assembly 8, and the monitoring data is transmitted to the control unit 9.

[0046] Furthermore, the internal pressure value of the air spring 3 is monitored in real time by the pressure sensor 8a, and the data signal is transmitted to the control unit 9; the displacement transformation of the moving end of the air spring 3 during the inflation or exhaust process is monitored in real time by the displacement sensor 8b, and the data signal is transmitted to the control unit 9; the inclination angle data of the moving end of the air spring 3 during the inflation or exhaust process is monitored in real time by the inclination sensor 8c, and the data signal is transmitted to the control unit 9.

[0047] S2. Constructing in the control unit 9 a pressure-displacement correlation standard model when the air spring 3 works normally and a pressure-displacement correlation fault diagnosis model when a fault occurs, and determining a boundary value of the pressure-displacement correlation fault diagnosis model.

[0048] Specifically, the construction process of each of the above models includes:

[0049] Step S2.1, combining the internal pressure (P)-load (W) test standard of the air spring 3 when it leaves the factory and the effective action area Aq of the air spring, use formula (1) to calculate the relationship between the thrust function (F) and the internal pressure (P1);

[0050] F=(P1-P0)Aq (1)

[0051] Among them, F is the thrust function, P1 is the internal pressure of the air spring, and P0 is the standard atmospheric pressure;

[0052] Step S2.2, calculating the minimum kinetic energy (Emin) and the maximum kinetic energy value (Emax) required for the air spring (3) to overcome relevant resistance (for example, the effect of the weight of the pantograph head and other forces) during the pantograph raising process;

[0053] Emin≤E≤Emax (2)

[0054] E=f(F,S,t) (3)

[0055] Among them, E is the kinetic energy of the air spring, F is the thrust function, S is the displacement value, and t is the working time of the air spring;

[0056] Step S2.3, combining the pantograph raising time limit (T), further calculating the internal pressure (P1) variation range and the corresponding displacement (S) variation relationship during the working process of the air spring 3, and constructing the pressure-displacement correlation standard model when the air spring 3 is working normally, as shown in formula (4);

[0057] S=f(E,P1,t) (4)

[0058] like Figure 4 As shown, the relationship curve between the internal pressure (P1) and displacement (s) of the pantograph air spring is nonlinear.

[0059] It can be understood that T is the time limit requirement for the pantograph to be raised, and the air spring working time t can be less than the pantograph raising time. Since there is also a buffer plus a controller to control the pantograph raising time, the two times may not be consistent.

[0060] Step S2.4, combining the correction and verification results of multiple groups of vehicle assembly data, construct a pressure-displacement correlation fault diagnosis model when the air spring 3 fails, and design the boundary values ​​of the internal pressure and displacement changes under the fault state according to the failure mode of the air spring 3.

[0061] S3, the control unit 9 compares the value of the pressure-displacement correlation model of the air spring 3 in the actual working process with the value of the pressure-displacement correlation fault diagnosis model, and sends a corresponding control instruction to the alarm device 10 according to the comparison result, so as to prompt the maintenance personnel to repair the air spring 3. Alternatively, the control unit 9 compares the real-time tilting angle with the preset tilting angle based on the tilting angle signal of the air spring 3 collected in real time by the tilt sensor 8c, and sends a corresponding control instruction to the alarm device 10 according to the comparison result.

[0062] In this embodiment, the relationship curve between the internal pressure and displacement of the air spring of the pantograph is nonlinear. By measuring the parameters of pressure and displacement during the filling and exhausting process of the air spring 3, an innovative pressure-displacement correlation model during the filling and exhausting process of the air spring 3 is constructed. The pressure-displacement correlation fault diagnosis model is determined by experiment, and the deterioration trend and fault form of the air spring 3 can be accurately diagnosed. By measuring the changes in pressure and displacement of the air spring 3 during the process of raising and lowering the pantograph, the constructed fault model is used to determine whether the air spring 3 has deteriorated, and an alarm instruction is issued through the control unit 9 to indicate that the color indicator light of the alarm device 10 is on; or, the control unit compares the real-time tilt angle with the preset tilt angle according to the collected real-time tilt angle signal, and according to the comparison result, the alarm device (indicator light) is controlled by the instruction to indicate, so as to prompt the maintenance personnel to perform maintenance operations, thereby improving the maintenance efficiency of the maintenance personnel and saving maintenance costs.

[0063] Specific working process:

[0064] S1. When the pantograph of a rail vehicle is working normally, after the pantograph raising operation is started, the compressed air in the air system enters the air spring 3 through the pipeline from the air inlet, and the inflation pressure causes the moving end of the air spring 3 to move forward, and the connecting rod 11 pushes the lower arm 4 to rotate. At the same time, through the cooperation of the pull rod 5, the upper arm 6 is raised upward, so that the bow head 7 is in contact with the contact network and a certain contact pressure is maintained to complete the current receiving process.

[0065] In the above process, the inflation process of the air spring 3 and the internal pressure value in the pressure holding state are monitored in real time through the pressure sensor 8a, and the data signal is transmitted to the control unit 9 in a time series. The displacement data of the moving end of the air spring 3 during the inflation process is monitored in real time through the displacement sensor 8b, and the monitoring data signal is transmitted to the control unit 9 in a time series. The inclination angle data of the moving end of the air spring 3 during the inflation process is monitored in real time through the inclination sensor 8c, and the monitoring data signal is transmitted to the control unit 9 in a time series.

[0066] S2. Constructing in the control unit 9 a pressure-displacement correlation standard model when the air spring 3 works normally and a pressure-displacement correlation fault diagnosis model when a fault occurs, and determining a boundary value of the pressure-displacement correlation fault diagnosis model.

[0067] Specifically, the construction process of each of the above models includes:

[0068] Step S2.1, combining the internal pressure (P)-load (W) test standard of the air spring 3 when it leaves the factory and the effective action area Aq of the air spring, use formula (1) to calculate the relationship between the thrust function (F) and the internal pressure (P1);

[0069] F=(P1-P0)Aq (1)

[0070] Among them, F is the thrust function, P1 is the internal pressure of the air spring, and P0 is the standard atmospheric pressure;

[0071] Step S2.2, calculating the minimum kinetic energy (Emin) and maximum kinetic energy (Emax) required for the air spring 3 to overcome relevant resistance (for example, the action of the bow head gravity and other forces) during the pantograph raising process;

[0072] Emin≤E≤Emax (2)

[0073] E=f(F,S,t) (3)

[0074] Among them, E is the kinetic energy of the air spring, F is the thrust function, S is the displacement value, and t is the working time of the air spring;

[0075] Step S2.3, combining the pantograph raising time limit (T), further calculating the internal pressure (P1) variation range and the corresponding displacement (S) variation relationship during the working process of the air spring 3, and constructing the pressure-displacement correlation standard model when the air spring 3 is working normally, as shown in formula (4);

[0076] S=f(E,P1,t) (4)

[0077] Step S2.4, combining the correction and verification results of multiple groups of vehicle assembly data, constructing a pressure-displacement correlation fault diagnosis model when the air spring 3 fails;

[0078] Step S2.5, for the failure mode of the air spring 3, such as air spring failure caused by temperature, acid, alkali, salt or environmental humidity, design the boundary values ​​of the internal pressure (P) and displacement (S) changes under the failure state.

[0079] S3, the control unit 9 constructs a pressure-displacement correlation model of the air spring 3 in the actual working process based on the pressure signal and displacement signal of the air spring 3 collected in real time by the sensor assembly 8, compares the numerical value of the pressure-displacement correlation model with the numerical value of the pressure-displacement correlation fault diagnosis model, and sends corresponding control instructions to the alarm device 10 according to the comparison result.

[0080] Specifically, when the air spring 3 shows a deterioration trend due to environmental factors such as temperature, acid, alkali, and salt, the pressure-displacement correlation model constructed by the control unit 9 based on the data signals collected by the pressure sensor 8a and the displacement sensor 8b will exceed the boundary value of the pressure-displacement correlation standard model, and the control unit 9 sends an alarm instruction to the alarm device 10 to prompt the maintenance personnel to repair the air spring 3. Alternatively, the control unit 9 compares the air spring tilt angle signal collected in real time by the tilt sensor 8c with the preset tilt angle value. If the range of the tilt angle exceeds the preset value, it can be determined that the air spring has a fault and it is necessary to remind the maintenance personnel to repair it.

[0081] S4. When the pantograph lowering operation is started, the air spring 3 is exhausted to reduce the internal pressure, so that the pantograph is lowered to disconnect the current; the pressure sensor 8a, the displacement sensor 8b and the inclination sensor 8c transmit the collected real-time pressure data signal, displacement data signal and tilt angle data signal to the control unit 9, and the control unit 9 compares the value of the pressure-displacement correlation model with the value of the pressure-displacement correlation fault diagnosis model, or compares the real-time tilt angle with the preset value, and sends corresponding control instructions to the alarm device 10 according to the comparison result.

[0082] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any technician familiar with the art can use the above disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present invention without departing from the spirit and technical solutions of the present invention, or modify them into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solutions of the present invention still fall within the scope of protection of the technical solutions of the present invention.

Claims

1. An urban rail vehicle pantograph air spring alarm system, characterized in that: include: A chassis (2), an air spring (3), a pantograph assembly, a sensor assembly (8), a control unit (9), and an alarm device (10); the air spring (3) is mounted on the chassis (2), the bottom of the pantograph assembly is connected to the chassis (2) and the air spring (3) respectively, and as the air spring (3) is inflated or deflated, the pantograph assembly performs corresponding pantograph raising and lowering actions; the sensor assembly (8) is connected to the air spring (3) and is used to monitor the internal gas pressure of the air spring (3), as well as the displacement change and tilt angle change of the air spring (3) during the inflating or deflation process, and transmit the monitoring data to the control unit (9); the alarm device (10) is connected to the control unit (9) and is used to receive a control instruction sent by the control unit (9) and to generate an alarm; The sensor assembly (8) comprises an inclination sensor (8c), and a connecting rod (11) is provided at the moving end of the air spring (3); the inclination sensor (8c) is arranged at the center position of the connecting rod (11) at the moving end of the air spring (3) and is used to monitor the change in the inclination angle of the air spring (3) during the process of charging and discharging. The sensor assembly (8) further comprises a displacement sensor (8b), wherein the displacement sensor (8b) is arranged on a connecting rod (11) at the moving end of the air spring (3) and is used to monitor the displacement change of the air spring (3) during the filling and exhausting process; The sensor assembly (8) further comprises a pressure sensor (8a); an air inlet is provided at the fixed end of the air spring (3), and the air inlet is connected to the air circuit system; the pressure sensor (8a) is arranged at the air inlet of the air spring (3) and is used to monitor the internal gas pressure of the air spring (3); Combined with the internal pressure (P)-load (W) test standard of the air spring (3) when it leaves the factory and the effective action area Aq of the air spring, the relationship between the thrust function (F) and the internal pressure (P1) is calculated using formula (1); F=(P1-P0)Aq(1) Among them, F is the thrust function, P1 is the internal pressure of the air spring, and P0 is the standard atmospheric pressure; Calculate the minimum kinetic energy (Emin) and maximum kinetic energy (Emax) required for the air spring (3) to overcome the relevant resistance during the pantograph raising process; Emin≤E≤Emax(2) E=f1(F,S,t)(3) Among them, E is the kinetic energy of the air spring, F is the thrust function, S is the displacement value, and t is the working time of the air spring; Combined with the pantograph raising time limit (T), the internal pressure (P1) variation range and the corresponding displacement (S) variation relationship of the air spring (3) during operation are calculated, and a pressure-displacement correlation standard model of the air spring (3) during normal operation is constructed, as shown in formula (4); S=f2(E,P1,t)(4) Combined with the correction and verification results of multiple sets of vehicle assembly data, a pressure-displacement correlation fault diagnosis model for the air spring (3) when a failure occurs is constructed, and the boundary values ​​of the internal pressure and displacement changes under the corresponding fault state are designed.

2. The urban rail vehicle pantograph air spring alarm system according to claim 1, characterized in that: The pantograph assembly comprises: a lower arm (4), a pull rod (5), an upper arm (6) and a bow head (7); the bottom of the lower arm (4) is connected to the moving end of the air spring (3); the bottom of the pull rod (5) is connected to the end of the base frame (2); the top of the lower arm (4) and the top of the pull rod (5) are both connected to the bottom of the upper arm (6); and the top of the upper arm (6) is connected to the bow head (7); as the air spring (3) is inflated or deflated, the moving end of the air spring (3) pushes the lower arm (4) to rotate, so that the upper arm (6) raises or lowers the bow head (7).

3. The urban rail vehicle pantograph air spring alarm system according to claim 1, characterized in that: It also comprises a supporting insulating base (1), the bottom of the supporting insulating base (1) being fixedly connected to the top of the urban rail vehicle, and the top of the supporting insulating base (1) being fixedly connected to the bottom of the base frame (2).

4. A control method for the pantograph air spring alarm system of a rail vehicle based on any one of claims 1 to 3, characterized in that: The following steps are involved: S1, inflating or exhausting the air spring (3) to achieve contact or disconnection between the pantograph assembly and the contact network, monitoring the internal gas pressure of the air spring (3) and the position change of the air spring (3) during the inflation and exhaust process in real time through the sensor assembly (8), and transmitting the monitoring data to the control unit (9); S2, constructing in the control unit (9) a pressure-displacement correlation standard model when the air spring (3) works normally and a pressure-displacement correlation fault diagnosis model when a fault occurs, and determining a boundary value of the pressure-displacement correlation fault diagnosis model; S3, the control unit (9) constructs a pressure-displacement correlation model of the air spring (3) in the actual working process based on the pressure signal and displacement signal of the air spring (3) collected in real time by the sensor assembly (8), compares the value of the pressure-displacement correlation model with the value of the pressure-displacement correlation fault diagnosis model, and sends a corresponding control instruction to the alarm device (10) according to the comparison result; The step S2 further comprises: Step S2.1, combining the internal pressure (P)-load (W) test standard of the air spring (3) when it leaves the factory and the effective action area Aq of the air spring, use formula (1) to calculate the relationship between the thrust function (F) and the internal pressure (P1); F=(P1-P0)Aq(1) Among them, F is the thrust function, P1 is the internal pressure of the air spring, and P0 is the standard atmospheric pressure; Step S2.2, calculating the minimum kinetic energy (Emin) and the maximum kinetic energy value (Emax) required for the air spring (3) to overcome the relevant resistance during the pantograph raising process; Emin≤E≤Emax(2) E=f1(F,S,t)(3) Among them, E is the kinetic energy of the air spring, F is the thrust function, S is the displacement value, and t is the working time of the air spring; Step S2.3, combining the pantograph raising time limit (T), further calculating the internal pressure (P1) variation range and the corresponding displacement (S) variation relationship during the working process of the air spring (3), and constructing the pressure-displacement correlation standard model of the air spring (3) during normal working, as shown in formula (4); S=f2(E,P1,t)(4) Step S2.4, combining the correction and verification results of multiple sets of vehicle assembly data, construct a pressure-displacement correlation fault diagnosis model when the air spring (3) fails, and design the boundary values ​​of the internal pressure and displacement changes under the corresponding fault state.

5. The control method according to claim 4, characterized in that: In step S1, the sensor assembly (8) comprises a pressure sensor (8a), a displacement sensor (8b) and an inclination sensor (8c); the internal pressure value of the air spring (3) is monitored in real time by the pressure sensor (8a), and a data signal is transmitted to the control unit (9); the displacement transformation of the moving end of the air spring (3) during the inflation or deflation process is monitored in real time by the displacement sensor (8b), and a data signal is transmitted to the control unit (9); and the tilt angle data of the moving end of the air spring (3) during the inflation or deflation process is monitored in real time by the inclination sensor (8c), and a data signal is transmitted to the control unit (9).

6. The control method according to claim 5, characterized in that: The step S3 also includes: the control unit (9) compares the real-time tilting angle with the preset tilting angle based on the tilting angle signal of the air spring (3) collected in real time by the tilt sensor (8c), and sends a corresponding control instruction to the alarm device (10) according to the comparison result.

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