A dynamic stiffness high-low switchable anti-sway damper and a control system thereof

Abstract

The application provides a dynamic stiffness high-low switchable anti-snaking shock absorber and a control system thereof. The shock absorber comprises three chambers, namely a compression chamber, a stretching chamber and an oil storage chamber. A first one-way valve (1), a first damping valve (1) and a first pressure relief valve (1) are arranged between the stretching chamber and the oil storage chamber. A second one-way valve (2), a second damping valve (2) and a second pressure relief valve (2) are arranged between the compression chamber and the oil storage chamber. The compression chamber and the stretching chamber are separated by a piston. The oil flow direction between the compression chamber and the stretching chamber is determined by a reversing valve and a third one-way valve (3). The application also designs a control system of the dynamic stiffness high-low switchable anti-snaking shock absorber. The system comprises a controller, a data collector and the dynamic stiffness high-low switchable anti-snaking shock absorber. The data collector comprises a frame lateral acceleration sensor and a vehicle body lateral acceleration sensor. The data collector is connected with the signal input end of the controller.

Description

Technical Field

[0001] This invention belongs to the field of vibration dampers for rail vehicles, and particularly relates to a dynamic stiffness-switching anti-hunting vibration damper and its control system. Background Technology

[0002] Anti-hunting dampers are installed between the car body and the bogies and are the most important suspension components for preventing high-speed trains from hunting and becoming unstable. Based on the different directions of internal oil flow, anti-hunting dampers can be divided into two types: unidirectional flow and bidirectional flow. These two types of anti-hunting dampers exhibit significantly different dynamic characteristics. Unidirectional flow anti-hunting dampers have a longer oil path and are characterized by "lower dynamic stiffness," while bidirectional flow anti-hunting dampers have a shorter oil path and are characterized by "higher dynamic stiffness."

[0003] Traditional anti-hunting vibration dampers are typically designed during the train dynamics design phase based on partially known wheel-rail matching relationships. The choice between unidirectional and bidirectional oil flow type dampers is usually determined by the effective taper range of the wheel-rail matching. The dynamic stiffness range of the selected damper is also applicable within the considered wheel-rail matching range. A higher effective wheel-rail taper requires greater dynamic stiffness from the anti-hunting damper, leading to the selection of a bidirectional oil flow type damper with higher dynamic stiffness. Conversely, a lower effective wheel-rail taper requires less dynamic stiffness, resulting in the selection of a unidirectional oil flow type damper with lower dynamic stiffness. However, regardless of the type of damper chosen, once the structure is determined, the oil flow direction cannot be changed, and the dynamic stiffness of the damper cannot be adjusted.

[0004] Because high-speed trains operate across a wide geographical area in my country, the actual wheel-rail matching relationship changes dynamically with time and space. The dispersion of rail grinding profiles on the same line and the abrupt changes in wheel-rail relationships during cross-line operation may exceed the applicable range of the original suspension parameter design. Therefore, anti-hunting dampers with fixed dynamic stiffness are difficult to meet the stability requirements of vehicles under various wheel-rail contact conditions. For example, when a train passes through a section with excessively ground rails, the excessively low wheel-rail matching equivalent cone under new wheel conditions may cause low-frequency lateral swaying of 0.5–2Hz (referred to as car body hunting). Using anti-hunting dampers with lower dynamic stiffness can significantly suppress car body hunting and improve passenger comfort. However, under worn wheel conditions, excessively high wheel-rail matching equivalent cone may cause high-frequency bogie hunting of 3–9Hz. Using anti-hunting dampers with higher dynamic stiffness can significantly suppress bogie hunting and improve vehicle operation safety. It is evident that the dynamic stiffness requirements for anti-hunting dampers differ between low-frequency car body hunting and high-frequency bogie hunting. While using unidirectional hydraulic anti-hunting dampers with low dynamic stiffness is beneficial for improving the car body's hunting stability under low wheel-rail equivalent cone conditions with new wheels, it is detrimental to the bogie's hunting stability under higher wheel-rail equivalent cone conditions with worn wheels. Conversely, using bidirectional hydraulic anti-hunting dampers with high dynamic stiffness is beneficial for improving the bogie's hunting stability under higher wheel-rail equivalent cone conditions with worn wheels, but it is detrimental to the car body's hunting stability under lower wheel-rail equivalent cone conditions with new wheels. Since my country's high-speed trains all use traditional anti-hunting dampers, current measures such as "shortening wheel refinishing cycles," "frequent rail grinding," or "reduced speed operation" are used to ensure dynamic performance. This seriously affects the operational efficiency of high-speed rail and increases the maintenance costs and difficulties of vehicles and lines.

[0005] It is evident that optimizing the dynamic stiffness of traditional anti-hunting dampers requires taking into account both high and low equivalent tapers and the lateral stability of vehicles under different wheel-rail contact states. Therefore, traditional fixed-parameter anti-hunting dampers cannot achieve this goal well. Summary of the Invention

[0006] To address the aforementioned shortcomings in the prior art, the present invention provides a dynamic stiffness-switching anti-hunting vibration damper. The damper includes three chambers: a compression chamber, a tension chamber, and an oil storage chamber. A first check valve (1), a first damping valve (1), and a first pressure relief valve (1) are provided between the tension chamber and the oil storage chamber. A second check valve (2), a second damping valve (2), and a second pressure relief valve (2) are provided between the compression chamber and the oil storage chamber. The compression chamber and the tension chamber are separated by a piston. The direction of oil flow between the compression chamber and the tension chamber is determined by a reversing valve and a third check valve (3).

[0007] This invention also designs a control system for a dynamically stiffness-switching anti-hunting damper. The system includes a controller, a data acquisition unit, and the dynamically stiffness-switching anti-hunting damper as described above. The data acquisition unit includes a frame lateral acceleration sensor and a vehicle body lateral acceleration sensor, respectively installed at a frame acceleration measuring point above the axle box and a stability measuring point on the floor surface at the end of the vehicle body. The frame lateral acceleration sensor and the vehicle body lateral acceleration sensor are connected to the signal input terminal of the controller, and the signal output terminal of the controller is connected to the dynamically stiffness-switching anti-hunting damper.

[0008] The beneficial effects of this invention are:

[0009] This invention provides a dynamic stiffness-switching anti-hunting vibration damper that can switch between a lower dynamic stiffness unidirectional flow hydraulic anti-hunting vibration damper and a higher dynamic stiffness bidirectional flow hydraulic anti-hunting vibration damper under switch control. Utilizing its ability to switch dynamic stiffness, it achieves adaptive stability for high-speed trains under a wide range of wheel-rail contact conditions. Particularly under extreme wheel-rail contact conditions, it improves the train's lateral dynamic performance and enhances its adaptability to track operation. It can solve the problems of existing vehicles requiring advance wheel refinishing and frequent rail grinding, resulting in a large amount of maintenance work, thus improving high-speed rail operation efficiency and reducing high-speed rail maintenance costs. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of a dynamic stiffness-adjustable anti-hunting vibration damper.

[0011] Figure 2 This is a schematic diagram of the working mode A of the dynamic stiffness switchable anti-hunting vibration damper.

[0012] Figure 3 This is a schematic diagram of the working mode B of the dynamic stiffness switchable anti-hunting vibration damper.

[0013] Figure 4 This is the controller decision logic diagram for a dynamic stiffness-switching anti-hunting vibration damper.

[0014] Figure 5 The diagram shows the dynamic stiffness and dynamic damping characteristics of the vibration damper under two operating modes.

[0015] Figure 6 This is a schematic diagram of the hydraulic stiffness during the tension and compression strokes of the shock absorber under two working modes. Detailed Implementation

[0016] This invention designs a controllable anti-hunting vibration damper that can switch between a bidirectional oil flow structure and a unidirectional oil flow structure, thereby achieving high and low dynamic stiffness switching. Figure 1The structural principle of this dynamically stiffness-switching anti-hunting vibration damper is presented. It consists of three chambers: a compression chamber, a tension chamber, and an oil reservoir. The compression and tension chambers are separated by a piston, and the direction of oil flow between them is determined by a reversing valve and a third check valve 3. A first check valve 1, a first damping valve 1, and a first pressure relief valve 1 are installed between the tension chamber and the oil reservoir. A second check valve 2, a second damping valve 2, and a second pressure relief valve 2 are installed between the compression chamber and the oil reservoir. The purpose of these valve systems is to achieve the desired damping characteristics and prevent excessive oil pressure in the damper, thus limiting the maximum damping force of the damper.

[0017] Depending on the operating state of the directional valve, the shock absorber has two operating modes: Mode A – bidirectional oil flow mode and Mode B – unidirectional oil flow mode. The function of the directional valve is to control the flow direction of the hydraulic oil, thereby enabling the selection and switching of different operating modes. By controlling the energization state of the directional valve (energized or de-energized), the control system can switch between different modes, thereby adjusting the dynamic stiffness of the anti-hunting shock absorber.

[0018] By default, the reversing valve is de-energized, and the shock absorber operates in mode A, which is a bidirectional oil flow anti-hunting shock absorber structure. See [link / details]. Figure 2 During the extension stroke, the piston rod extends, increasing the pressure in the extension chamber and forcing hydraulic oil to flow from the extension chamber through the first damping valve 1 to the reservoir. Simultaneously, the volume of the compression chamber increases, causing a pressure drop, and the second check valve 2 opens, allowing hydraulic oil to flow from the reservoir to the compression chamber. During the compression stroke, the pressure in the compression chamber increases, and hydraulic oil flows from the compression chamber through the second damping valve 2 to the reservoir. Simultaneously, the volume of the extension chamber increases, causing a pressure drop, and the first check valve 1 opens, allowing hydraulic oil to flow from the reservoir to the extension chamber. The first damping valve 1 is connected in parallel with the first pressure relief valve 1, and the second damping valve 2 is connected in parallel with the second pressure relief valve 2, each limiting the maximum damping force of the shock absorber. The pressure relief valve has a preset maximum safe pressure value; once the oil pressure in the oil circuit exceeds the safe pressure value, the pressure relief valve immediately opens, and the oil in the main oil circuit of the shock absorber flows directly back to the reservoir.

[0019] When the reversing valve is energized, the oil circuit switches, and the shock absorber operates in mode B, which is a unidirectional oil flow anti-hunting shock absorber structure. See [link / description]. Figure 3 During the stretching stroke, the hydraulic circuit is the same as in mode A. The piston rod extends, forcing hydraulic oil from the stretching chamber through the first damping valve 1 to the reservoir. Simultaneously, the volume of the compression chamber increases, causing a pressure decrease, and the second check valve 2 opens, allowing hydraulic oil to flow from the reservoir to the compression chamber. During the compression stroke, the piston moves inward, increasing the pressure in the compression chamber, opening the third check valve 3 connected to the reversing valve, and allowing oil to flow from the compression chamber to the stretching chamber. Because the total volume of the stretching and compression chambers decreases, oil then flows from the stretching chamber back to the reservoir through the first damping valve 1.

[0020] As can be seen, in mode A, the hydraulic oil flows through different damping valves during the stretching and compression strokes, namely the first damping valve 1 and the second damping valve 2, and the oil flow directions are also different. Therefore, the shock absorber is a bidirectional flow structure. In mode B, the hydraulic oil always flows through the same damping valve, namely the first damping valve 1, during the stretching and compression strokes, and the oil flow directions are the same. Therefore, the shock absorber is a unidirectional flow structure.

[0021] This invention patent, through its designed hydraulic circuit, along with switching valves, check valves, damping valves, and pressure relief valves, enables the switching between single and bidirectional hydraulic circuits of the shock absorber. This allows for adjustable dynamic stiffness, meeting the requirements of different dynamic stiffnesses in anti-hunting shock absorbers for both low-frequency car body hunting stability and high-frequency bogie hunting stability. It overcomes the shortcomings of traditional anti-hunting shock absorbers, such as non-adjustable dynamic stiffness and inability to adapt to wide variations in wheel-rail matching equivalent taper. This increases the adaptability of train operation, helps extend wheel rewinding cycles, and reduces maintenance costs.

[0022] This invention also designs a control system for a dynamically stiffness-switching anti-hunting damper. The system includes a controller, a data acquisition unit, and the dynamically stiffness-switching anti-hunting damper as described above. The data acquisition unit includes a frame lateral acceleration sensor and a vehicle body lateral acceleration sensor, respectively installed at a frame acceleration measuring point above the axle box and a stability measuring point on the floor surface at the end of the vehicle body. The frame lateral acceleration sensor and the vehicle body lateral acceleration sensor are connected to the signal input terminal of the controller, and the signal output terminal of the controller is connected to the dynamically stiffness-switching anti-hunting damper.

[0023] The data acquisition unit collects the lateral acceleration of the vehicle frame (3-9Hz bandpass filter) and the lateral acceleration of the vehicle body (0.5-2Hz bandpass filter) in real time, and transmits the detected acceleration signals to the controller. The controller uses a built-in algorithm to determine the vehicle's operating status in real time. Based on the judgment logic, the controller issues power-on or power-off commands to control the working status of the aforementioned dynamic stiffness-switching anti-hunting damper in real time, ensuring that the vehicle operates in the optimal state.

[0024] The controller's decision logic process is as follows: Figure 4 As shown:

[0025] Step 1: Determine if the vehicle speed is less than 160 km / h. If yes, proceed to Step 2; otherwise, proceed to Step 3.

[0026] Step 2: Power on the shock absorber and open the reversing valve. The shock absorber operates in mode B, which is the unidirectional flow mode of the oil. The shock absorber provides lower dynamic stiffness to ensure the stability of the vehicle in the speed range where the vehicle body is prone to snake-like movements and to avoid the swaying phenomenon when the vehicle passes through the switch at low speed; return to step 1.

[0027] Step 3: With the shock absorber de-energized and the reversing valve closed, the shock absorber operates in Mode A, i.e., the bidirectional flow mode of the oil. The shock absorber provides higher dynamic stiffness to ensure the bogie's hunting stability and improve driving safety; proceed to Step 4.

[0028] Step 4: Determine whether the root mean square value of the ISO body's lateral weighted acceleration is greater than 0.2 m / s² for two consecutive times. 2 If so, it is determined to be a low-frequency vehicle body snaking motion state. The controller responds to the change in vehicle state, triggers the shock absorber to be energized, opens the reversing valve, and the shock absorber operates in mode B, i.e., the oil unidirectional flow mode. The shock absorber provides lower dynamic stiffness to ensure vehicle body snaking stability and improve passenger ride comfort; proceed to step five; if not, return to step one.

[0029] Step 5: Timing the energizing time of the shock absorber; proceed to step 6.

[0030] Step Six: Determine if the vibration damper has been energized for more than 10 minutes. If so, de-energize the vibration damper, close the reversing valve, and the vibration damper will operate in Mode A, i.e., the bidirectional flow mode of the oil. This will prevent the vibration damper from operating for an extended period after the train has left the low-taper section of the wheel-rail mismatch, thereby increasing the service life of the vibration damper. Return to Step One. If not, proceed to Step Seven.

[0031] Step 7: Determine if the lateral acceleration of the frame is greater than 0.4g for 6 consecutive times. If so, the shock absorber is not powered on, the reversing valve is closed, and the shock absorber operates in mode A, i.e., the bidirectional flow mode of the oil. The shock absorber provides higher dynamic stiffness to ensure the bogie's hunting stability and improve operational safety; return to step 1; if not, proceed to step 6.

[0032] Based on the above logic, the controller can determine the required dynamic stiffness parameters of the shock absorbers according to the current operating status of the vehicle, and apply energizing or de-energizing signals to the shock absorbers. This ensures that the shock absorbers can adjust their dynamic stiffness parameters in real time according to the vehicle's operating requirements, keeping the train suspension system in an optimal matching state. It also ensures compatibility with the operating needs of vehicles in different geographical environments and on different tracks, effectively extending vehicle maintenance cycles, increasing vehicle lifespan, and reducing operating costs.

[0033] By establishing a physical parameter model of the vibration damper, the variation laws of the dynamic stiffness and dynamic damping of the anti-hunting vibration damper with excitation frequency and amplitude under different operating modes were calculated. (See...) Figure 5 As can be seen, the dynamic stiffness switchable anti-hunting vibration damper proposed in this invention can provide two dynamic stiffness characteristics, high and low, with dynamic damping essentially unaffected. In contrast, traditional anti-hunting vibration dampers can only provide one type of dynamic stiffness characteristic curve.

[0034] The mechanism underlying the significant difference in dynamic stiffness of the anti-hunting damper under the two modes is as follows:

[0035] When the anti-hunting damper is subjected to small amplitude and high frequency dynamic excitation, the stiffness effect of the damper oil comes into play.

[0036] During the stretching stroke: In modes A and B, the oil always flows from the stretching chamber to the reservoir chamber through damping valve 1, thus accumulating high pressure in the stretching chamber, see... Figure 6 a and Figure 6 b. In this case, the stiffness effect generated by oil compression is determined by the tension chamber, and can be expressed by the following formula:

[0037]

[0038] During the compression stroke: In mode A, the oil flows from the compression chamber to the reservoir chamber through damping valve 2, thus accumulating a high pressure in the compression chamber, see... Figure 6 a. In this case, the stiffness effect generated by oil compression is determined by the compression chamber and can be expressed as:

[0039]

[0040] In mode B, the oil flows from the compression chamber to the tension chamber, and then through damping valve 1 to the reservoir. Therefore, the pressure in both the compression and tension chambers increases, see... Figure 6 (b) In this case, the stiffness effect generated by oil compression is determined by both the compression chamber and the tension chamber, and can be expressed as:

[0041]

[0042] In this invention patent, the piston area is twice the piston rod area, therefore the compression chamber volume is twice the tension chamber volume. According to formulas (1) to (3), it can be seen that the average stiffness of the oil during the tension and compression strokes in mode A is significantly greater than that in mode B. This is the fundamental reason for the significant difference in dynamic stiffness between the two modes.

[0043] The formula symbols are explained as follows:

[0044] The tensile stiffness and compressive stiffness of the oil under working mode A. The tensile stiffness and compressive stiffness of the oil under working mode B;

[0045] E oil The elastic modulus of the oil;

[0046] A pis A is the piston area; rod A is the piston rod area; ring It is the piston annular area, which is the piston area minus the piston rod area;

[0047] V oil,reb V is the volume of the stretching cavity. oil,com This represents the volume of the compression chamber.

Claims

1. A dynamic stiffness-switching anti-hunting vibration damper, characterized in that: The shock absorber includes three chambers: a compression chamber, a tension chamber, and an oil reservoir. A first check valve, a first damping valve, and a first pressure relief valve are installed between the tension chamber and the oil reservoir. The first damping valve and the first pressure relief valve are connected in parallel, each limiting the maximum damping force of the shock absorber. A second check valve, a second damping valve, and a second pressure relief valve are installed between the compression chamber and the oil reservoir. The second damping valve and the second pressure relief valve are connected in parallel. The first and second pressure relief valves are preset with maximum safe pressure values. Once the oil pressure in the oil circuit exceeds the safe pressure value, the pressure relief valve immediately opens, and the oil in the main oil circuit of the shock absorber flows directly back to the oil reservoir. The compression chamber and the tension chamber are separated by a piston, and the direction of oil flow between the compression chamber and the tension chamber is determined by a reversing valve and a third check valve. By default, the reversing valve is de-energized, and the damper operates in mode A, which is a bidirectional flow hydraulic anti-hunting damper structure. During the extension stroke, the piston rod extends, the pressure in the extension chamber increases, forcing hydraulic oil to flow from the extension chamber to the reservoir chamber through the first damping valve. At the same time, the volume of the compression chamber increases, resulting in a pressure decrease, and the second check valve opens, allowing hydraulic oil to flow from the reservoir chamber to the compression chamber. During the compression stroke, the pressure in the compression chamber increases, and hydraulic oil flows from the compression chamber to the reservoir chamber through the second damping valve. At the same time, the volume of the extension chamber increases, resulting in a pressure decrease, and the first check valve opens, allowing hydraulic oil to flow from the reservoir chamber to the extension chamber. When the reversing valve is energized, the oil circuit switches, and the damper operates in mode B, which is a one-way flow anti-hunting damper structure. During the extension stroke, the piston rod extends, the pressure in the extension chamber increases, and the hydraulic oil is forced to flow from the extension chamber to the reservoir chamber through the first damping valve. At the same time, the volume of the compression chamber increases, resulting in a decrease in pressure. The second check valve opens, and the hydraulic oil flows from the reservoir chamber to the compression chamber. During the compression stroke, the piston moves inward, the pressure in the compression chamber increases, and the third check valve connected to the reversing valve opens. The oil flows from the compression chamber to the extension chamber. Since the total volume of the extension chamber and the compression chamber decreases, the oil flows from the extension chamber back to the reservoir chamber through the first damping valve.

2. The dynamic stiffness switchable anti-hunting vibration damper according to claim 1, characterized in that: During the stretching stroke, the oil flows from the stretching chamber to the oil storage chamber through the first damping valve. The stiffness effect generated by the oil compression is determined by the stretching chamber, and the stretching stiffness is expressed by the following formula: ； In the formula, The tensile stiffness of the oil under operating mode A and operating mode B. E oil The elastic modulus of the oil. A ring For piston annular flow area, V oil,reb This represents the volume of the stretching cavity.

3. The dynamic stiffness switchable anti-hunting vibration damper according to claim 1, characterized in that: During the compression stroke in working mode A, the oil flows from the compression chamber to the oil reservoir through the second damping valve. The stiffness effect generated by oil compression is determined by the compression chamber, and the compression stiffness is expressed by the following formula: ； In the formula, The compressive stiffness of the oil under operating mode A. E oil The elastic modulus of the oil. A pis For piston area, V oil,com This represents the volume of the compression chamber.

4. The dynamic stiffness-switching anti-hunting vibration damper according to claim 1, characterized in that: During the compression stroke in operating mode B, the oil flows from the compression chamber to the tension chamber, and then through the first damping valve to the oil reservoir. The pressure in both the compression and tension chambers increases. In this case, the stiffness effect generated by oil compression is jointly determined by the compression and tension chambers. The compression stiffness is expressed by the following formula: ； In the formula, This refers to the compressive stiffness of the oil in operating mode B. E oil The elastic modulus of the oil. A rod The piston rod area is... V oil,reb For the volume of the stretching cavity, V oil,com This represents the volume of the compression chamber.

5. A control system for a dynamic stiffness-switching anti-hunting vibration damper, characterized in that: The system includes a controller, a data acquisition unit, and a dynamic stiffness-switching anti-hunting damper as described in any one of claims 1-4. The data acquisition unit includes a frame lateral acceleration sensor and a vehicle body lateral acceleration sensor, which are respectively installed at the frame acceleration measurement point above the axle box and the stability measurement point on the floor surface at the end of the vehicle body. The frame lateral acceleration sensor and the vehicle body lateral acceleration sensor are respectively connected to the signal input terminal of the controller, and the signal output terminal of the controller is connected to the dynamic stiffness-switching anti-hunting damper. The data acquisition unit collects the frame lateral acceleration and the vehicle body lateral acceleration in real time, and transmits the detected acceleration signals to the controller after bandpass filtering. The controller judges the vehicle's operating status in real time through a built-in algorithm. Based on the judgment logic, the controller issues a power-on or power-off command to control the working mode of the dynamic stiffness-switching anti-hunting damper in real time, ensuring that the vehicle operates in the optimal state.

6. The control system according to claim 5, characterized in that: The controller's decision-making logic process is as follows: Step 1: Determine if the vehicle speed is less than 160km / h. If yes, proceed to Step 2; otherwise, proceed to Step 3. Step 2: Power on the shock absorber and open the reversing valve. The shock absorber operates in mode B, which is the unidirectional flow mode of the oil. The shock absorber provides lower dynamic stiffness to ensure the stability of the vehicle in the speed range where the vehicle body is prone to snake-like behavior and to avoid the swaying phenomenon when the vehicle passes through the switch at low speed. Return to step one; Step 3: With the shock absorber de-energized and the reversing valve closed, the shock absorber operates in Mode A, i.e., the bidirectional flow mode of the oil. The shock absorber provides higher dynamic stiffness to ensure the bogie's hunting stability and improve driving safety; proceed to Step 4. Step 4: Determine whether the root mean square value of the ISO body lateral weighted acceleration is greater than 0.2 m / s² for two consecutive times; If so, it is determined to be a low-frequency vehicle body snaking motion state. The controller responds to the change in vehicle state, triggers the shock absorber to be energized, opens the reversing valve, and the shock absorber operates in mode B, i.e., the oil unidirectional flow mode. The shock absorber provides lower dynamic stiffness to ensure vehicle body snaking stability and improve passenger ride comfort, and then executes step five; if not, return to step one. Step 5: Timing the energizing time of the shock absorber; proceed to step 6; Step Six: Determine if the vibration damper has been energized for more than 10 minutes. If so, de-energize the vibration damper, close the reversing valve, and the vibration damper will operate in Mode A, i.e., the bidirectional flow mode of the oil. This will prevent the vibration damper from operating for an extended period of time after the train has left the low-taper section of the wheel-rail mismatch, thereby increasing the service life of the vibration damper. Then return to Step One. If not, proceed to Step Seven. Step 7: Determine if the lateral acceleration of the frame is greater than 0.4g for 6 consecutive times. If so, the shock absorber is not powered on, the reversing valve is closed, and the shock absorber operates in mode A, i.e., the oil bidirectional flow mode. The shock absorber provides higher dynamic stiffness to ensure the bogie's hunting stability and improve operational safety. Then return to step 1. If not, proceed to step six.

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