Piston type energy accumulator position detection mechanism and control method thereof

Abstract

The invention discloses a piston type energy accumulator position detection mechanism and a control method thereof. The detection mechanism comprises a cylinder body, an end cover, a piston, a sleeve rod, a displacement sensor, a magnetic rod, an extension rod and a magnetic ring. The extension rod moves along with the piston, and a magnetic rod fixed on the displacement sensor is accommodated in a hollow cavity in the extension rod; the magnetic ring is fixed to the end of the extension rod. The displacement sensor measures the position of the piston in a non-contact mode by detecting the magnetic field change of the magnetic ring based on the magnetostriction or Hall effect principle. The device is further provided with a swing detection unit, radial deviation of the magnetic ring is detected through a Hall sensor arranged in the circumferential direction, and safety valves on the two sides of the sleeve rod are controlled to conduct directional exhaust according to the radial deviation, so that measurement errors caused by swing are compensated. The mechanism solves the problems that a traditional stay wire type sensor is prone to fatigue damage and a laser sensor is prone to pollution and failure, has the advantages of being compact in structure, convenient to install, high in anti-interference performance, long in service life and high in precision, and is suitable for piston position real-time monitoring and anti-collision protection under the high-frequency reciprocating working condition.

Description

Technical Field

[0001] This invention relates to piston hydraulic technology, and more particularly to a piston accumulator position detection mechanism and its control method. Background Technology

[0002] Piston accumulators are used to store hydraulic energy, buffer pressure fluctuations, and supplement system flow. Their basic working principle involves a piston dividing the cylinder into an oil chamber and a gas chamber. When the oil pressure is higher than the gas pressure in the gas chamber, the pressurized oil pushes the piston to compress the gas, converting hydraulic energy into gas potential energy for storage. When the oil pressure drops, the gas expands, pushing the piston in the opposite direction, converting the stored potential energy back into hydraulic energy for output.

[0003] In practical applications, especially in hydraulic potential energy recovery systems, piston accumulators often require high-frequency (≥1 million times / year) full-stroke charging and discharging operations, resulting in frequent reciprocating motion of the piston within the cylinder. If the piston reaches the cylinder's limit position, it is highly susceptible to rigid collision with the end cap, causing structural damage or functional failure of the accumulator. Therefore, real-time and accurate detection of the piston position is crucial for preventing overshoot or undershoot accidents.

[0004] Currently, there are two main methods for detecting piston position: Wire-type displacement sensors: These sensors use a mechanical contact measurement principle, connecting to the piston via a wire. During high-speed reciprocating motion, the wire and return spring are prone to detachment or breakage due to metal fatigue, resulting in a short sensor lifespan and a gradual decrease in accuracy, making them unsuitable for long-term, high-frequency operation.

[0005] Laser displacement sensors, while possessing high precision, have extremely stringent requirements for the cleanliness of the working environment due to their optical measurement principle. Oil mist or particulate matter present in the accumulator's gas chamber can severely interfere with the laser beam, causing signal attenuation or frequent failures, resulting in insufficient reliability.

[0006] Furthermore, both methods suffer from problems such as complex installation, high maintenance costs, and significant impact on the original sealing performance of the accumulator structure. Therefore, improvements to the existing technologies are necessary. Summary of the Invention

[0007] To address the shortcomings of the existing technology, this invention proposes a piston-type accumulator position detection mechanism and its control method.

[0008] The technical solution of this invention is implemented as follows: A piston-type accumulator position detection mechanism includes a cylinder, a first end cover, a second end cover, a piston, an oil chamber, and an air chamber, characterized in that... The sleeve rod is fixedly connected to the second end cap; A displacement sensor is installed on the top of the sleeve rod; A magnetic rod is connected to the displacement sensor and extends through the inside of the sleeve. An extension rod is disposed at one end of the piston near the second end cap and reciprocates with the piston. The extension rod has a hollow cavity, and the magnetic rod is located inside the hollow cavity. A magnetic ring is fixed to the end of the extension rod; The displacement sensor detects the piston position by detecting changes in the magnetic field of the magnetic ring.

[0009] In this invention, the extension rod is connected to the piston via a thread, and the magnetic ring is mounted at the end of the extension rod via a washer.

[0010] This invention also includes: At least one Hall sensor is disposed on the inner wall of the sleeve rod for detecting changes in the radial magnetic field of the magnetic ring. The Hall sensors are four in number and are evenly arranged circumferentially on the inner wall of the sleeve, with angular positions of 0°, 90°, 180° and 270° respectively.

[0011] In this invention, the Hall sensor calculates the swing center offset, total radial offset, and swing direction angle of the extension rod.

[0012] This invention also includes: At least two vent holes are provided on the side wall of the sleeve rod; The first safety valve and the second safety valve are respectively installed on one of the exhaust ports; wherein, the exhaust control unit controls the opening state and opening time of the safety valve based on the swing detection result.

[0013] In this invention, the exhaust control unit includes: When the swing direction angle is within the range of 0°±45° or 180°±45°, the first safety valve or the second safety valve is opened according to the sign of the offset. When the swing direction angle is within the range of 90°±45° or 270°±45°, the first safety valve and the second safety valve are opened simultaneously.

[0014] In this invention, when the swing direction angle is within the range of 0°±45° or 180°±45°, the opening time of the first safety valve and the second safety valve is calculated.

[0015] A control method for a position detection mechanism of a piston accumulator, characterized by comprising the following steps: S1: Set zero point and calibration; When the piston is in a fully discharged oil state and a fully filled oil state, the zero-point signal and full-scale signal of the displacement sensor are calibrated respectively. S2: Real-time piston position detection; The absolute position and position change of the piston are calculated by measuring the change in the magnetic field of the magnetic ring using a displacement sensor. S3: Swing detection and offset calculation; The radial magnetic field change of the magnetic ring is detected by a Hall sensor array, and the offset of the swing center, the total radial offset, and the swing direction angle are calculated. S4 safety valve control decision; Based on the swing direction angle and offset, the opening state and opening time of the first and second safety valves are controlled.

[0016] The piston-type accumulator position detection mechanism and control method of the present invention have the following beneficial effects: 1. Displacement detection is achieved through the interaction of the magnetic fields of the magnetic ring and the magnetic rod, completely avoiding the mechanical contact and friction of the pull-wire sensor. This solves the problems of wire breakage and jamming caused by metal fatigue, and achieves an ultra-long working life that matches the accumulator body, truly achieving maintenance-free operation. In particular, compared with installing a laser displacement sensor, it can avoid the serious interference of potential oil mist or particulate matter in the accumulator's gas cavity with the laser beam, which would lead to signal attenuation or even frequent failures and insufficient reliability.

[0017] 2. The displacement sensor is externally mounted on the top of the cylinder and extends into the hollow cavity inside the piston through the sleeve and magnetic rod. It does not occupy the space inside the cylinder, making it easy to install and maintain, and does not affect the original structural strength and sealing performance of the accumulator.

[0018] 3. The piston position is calculated based on the propagation time of the torsional stress wave in the waveguide wire, and the measurement is accurate and reliable. At the same time, the radial magnetic field change of the magnetic ring is detected in real time by the Hall sensor array arranged circumferentially on the inner wall of the sleeve, which can calculate the swing offset and direction of the extension rod, effectively identifying and compensating for alignment errors caused by gas fluctuations.

[0019] 4. Based on the swing detection results, selective venting is achieved through the safety valves on both sides of the sleeve, dynamically adjusting the internal air pressure of the sleeve to generate a reaction force to suppress the swing of the extension rod. The opening time and direction of the safety valves are optimized in real time based on the swing direction angle and offset ratio, ensuring accurate and efficient compensation and significantly improving the stability and reliability of displacement detection. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the position detection mechanism of the piston accumulator of the present invention; Figure 2 This is a schematic diagram of the position detection mechanism of the piston accumulator of the present invention; Figure 3 for Figure 1 Enlarged structural diagram at point A; Figure 4This is a schematic diagram of the position detection mechanism of the piston accumulator of the present invention; Figure 5 This is a graph of the position detection mechanism of the piston accumulator of the present invention. Figure 6 This is a flowchart of the control method for the position detection mechanism of the piston accumulator of the present invention.

[0021] The reference numerals in the attached drawings are as follows: cylinder 10, first end cover 20, oil inlet 21, second end cover 30, air inlet 31, piston 40, oil chamber 11, air chamber 12, sleeve 50, displacement sensor 51, magnetic rod 52, extension rod 41, air hole 41A, hollow cavity 42, magnetic ring 43, first safety valve 53, and second safety valve 54. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0023] Example 1 refer to Figures 1 to 5 As shown, this embodiment proposes a piston-type accumulator position detection mechanism including a cylinder 10. The upper and lower ends of the cylinder 10 are connected to a first end cover 20 and a second end cover 30 by vacuum electron beam welding or flange connection. The first end cover 20 is provided with an oil inlet 21, and the second end cover 30 is provided with an air inlet 31.

[0024] A piston 40 is slidably connected inside the cylinder 10, dividing the cylinder 10 into an oil chamber 11 and a gas chamber 12. When the oil pressure in the cylinder 10 is higher than the gas pressure in the gas chamber, pressurized oil enters the oil chamber, pushing the piston 40 upward, compressing nitrogen gas, and converting hydraulic energy into gas potential energy for storage. When the oil pressure in the cylinder 10 drops and falls below the gas pressure in the gas chamber, the compressed nitrogen gas expands, pushing the piston 40 downward, squeezing out the hydraulic oil in the oil chamber 11, and converting the potential energy back into hydraulic energy. The upward or downward movement can be represented as follows: Figure 2 The indicated movement is upward or downward.

[0025] Because piston accumulators often require high-frequency (≥1 million times / year) full-stroke oil charging and discharging operations, the piston 40 reciprocates frequently within the cylinder 10. When the piston moves to its extreme position within the cylinder 10, i.e., the uppermost or lowermost end, it is prone to rigid collision with the end cover, causing accumulator failure. A piston position detector is installed to prevent the piston from impacting the end cover during high-speed movement. Traditional piston detection methods include: wire-type displacement sensors, due to their mechanical contact measurement principle, are prone to detachment or breakage of the wire and return spring due to metal fatigue during high-speed reciprocating motion. Their limited mechanical life and gradually decreasing accuracy cannot match the long-term high-frequency operating conditions. Another method is laser displacement sensors, although highly accurate, their optical principle requires extremely high environmental cleanliness. Potential oil mist or particulate matter within the accumulator's gas chamber can severely interfere with the laser beam, leading to signal attenuation or even frequent failures, resulting in insufficient reliability.

[0026] In this embodiment, refer again Figures 1 to 3 As shown, the top of the second end cap 30 is connected to a sleeve rod 50 via a flange. A displacement sensor 51 is mounted on the top of the sleeve rod 50. The displacement sensor 51 has a magnetic rod 52 that penetrates the interior of the sleeve rod 50.

[0027] An extension rod 41 is provided at one end of the piston 40 near the second end cap 30. The extension rod 41 is threadedly connected to the piston 40 and moves up and down together with the piston 40. The extension rod 41 has a hollow cavity 42, and the magnetic rod 52 is located inside the hollow cavity 42.

[0028] Furthermore, a magnetic ring 43 is provided at the end of the extension rod 41 away from the piston 40, and the magnetic ring 43 is installed at the end of the extension rod 41 by means of a gasket.

[0029] In this embodiment, displacement measurement is achieved through the interaction between the magnetic ring 43 and the magnetic rod 52. The magnetic ring 43 moves with the extension rod 41 of the piston 40, while the magnetic rod 52 is fixed to the displacement sensor 51 and located inside the hollow cavity 42 of the extension rod 41. The displacement sensor 51 detects the change in the magnetic field generated by the magnetic ring 43 and outputs a signal related to the piston position.

[0030] Preferably, the displacement sensor 51 is a Hall effect sensor or a magnetostrictive sensor.

[0031] Based on the piston-type accumulator position detection mechanism described in this embodiment, the piston position is detected using a non-contact magnetic induction principle. Specifically, the displacement sensor 51 cooperates with the magnetic rod 52, and the magnetic ring 43 is fixed at the end of the extension rod 41 and moves with the piston 40. When the magnetic ring 43 moves along the magnetic rod 52, its magnetic field interacts with the magnetic rod 52, generating a torsional wave. The real-time position of the piston is calculated by measuring the propagation time of the torsional wave.

[0032] Specifically, the time required for the stress wave to propagate from its point of origin to the pickup fixed at the end of the magnetic rod is measured. The displacement calculation formula is: .

[0033] L represents the piston displacement to be calculated, which is the straight-line distance between the magnetic ring 43 and the zero point position of the magnetic rod 52; V: the propagation speed of the torsional stress wave in the waveguide wire, a fixed value determined by the waveguide wire material; This represents the time interval from the start of the transmitted current pulse to the point when the pickup receives the stress wave signal.

[0034] Typically, when piston 40 is in the fully discharged state (i.e., piston against the first end cap 20), the gas chamber volume is at its minimum. The position of magnetic ring 43 at this time is set as the zero displacement point, i.e., L=0. The corresponding sensor output signal is also calibrated as the zero-point signal. When piston 40 is in the fully filled state (i.e., piston against the second end cap 30), the oil chamber volume is at its maximum. The position of magnetic ring 43 at this time is recorded as the maximum displacement L. max The sensor's output signal is now calibrated to be a full-scale signal.

[0035] In this embodiment, detecting the absolute position of the piston mainly focuses on its positional change relative to a reference point or the previous moment. Among them, the change in position This represents the change in piston displacement over a period of time or relative to an initial reference position. Essentially, it is the difference in absolute position between two different moments, and the calculation formula is: .

[0036] In the formula, when When, it indicates that the piston moves towards the gas chamber; when When t1 is the piston moving towards the oil chamber; Y2 represents the absolute position of the piston measured at time t2; Y1 represents the absolute position of the piston measured at time t1, or the set initial reference position. This represents the pulse propagation time measured at time point t2; This represents the pulse propagation time measured at time point t1, or the time corresponding to the initial reference position.

[0037] In this embodiment, the displacement sensor 51 is externally mounted on the top of the cylinder and extends into the piston via a sleeve and a magnetic rod. This design does not occupy cylinder space, facilitating installation and maintenance without affecting the original structural strength and sealing of the accumulator. There is no physical connection or friction between the magnetic ring and the magnetic rod. This solves the problems of wire breakage and jamming caused by mechanical fatigue in traditional wire-type sensors, achieving an ultra-long service life that matches the accumulator body and truly enabling maintenance-free operation.

[0038] Because the magnetic ring and magnetic rod are designed to be non-contact, the gas in the air chamber enters the sleeve through the gap, causing the extension rod to oscillate slightly, which affects the displacement detection accuracy.

[0039] Preferably, the extension rod 41 has multiple air holes 41A on both sides that communicate with the hollow cavity 42. When the extension rod 41 moves up and down, the gas that has entered the hollow cavity 42 is discharged through the multiple air holes 41A on both sides to ensure the stability of the extension rod 41 during movement and prevent it from swaying slightly.

[0040] Preferably, a flexible gasket is installed at the end of the hollow cavity 42, through which the hollow cavity 42 contacts the magnetic rod 52. The flexible gasket has a certain degree of elasticity and compressibility, which can absorb and compensate for minor radial, axial, and angular deviations. This ensures that the magnets or components connected to both ends of the magnetic rod maintain good contact even with certain errors, avoiding localized stress concentration caused by rigid contact.

[0041] Example 2 Based on the above embodiments, further improvements are made to the embodiments. A sensor is installed on the inner wall of the sleeve 50 to detect changes in the radial magnetic field of the magnetic ring 43. The Hall sensor is not in contact with the magnetic ring 43. When the extension rod 41 swings, the magnetic ring 43 undergoes radial displacement, and the Hall sensor outputs a voltage signal proportional to the displacement.

[0042] The sleeve 50 has at least one vent hole with a diameter of 3mm installed on both sides. A first safety valve 53 and a second safety valve 54 are provided on the vent hole. The first safety valve 53 and the second safety valve 54 are located on both sides of the sleeve 50. The working pressure of the first safety valve 53 and the second safety valve 54 can reach 35-45MPa.

[0043] Furthermore, four Hall sensors are evenly arranged circumferentially on the inner wall of the sleeve 50, installed at 0°, 90°, 180°, and 270° respectively, forming a complete radial displacement. A conical motion model of the extension rod 41 oscillating in three-dimensional space is constructed: The length of extension rod 41 is set to The swing angle is Then the radial offset for:

[0044] Axial projection error:

[0045] Four Hall sensors are evenly arranged circumferentially on the inner wall of the sleeve 50, with corresponding outputs S1, S2, S3, and S4, and corresponding angular positions. , , as well as .

[0046] The calculations for the swing center offset are as follows:

[0047]

[0048] Where A represents the Hall sensor sensitivity, and then the total radial offset is calculated based on the above. as follows:

[0049] The swing direction angle of extension rod 41 is:

[0050] In this embodiment, the first safety valve 53 and the second safety valve 54 on the control sleeve 50 are used to release air, thereby reducing or compensating for the impact of the extension rod's swing on the displacement detection accuracy. Swing direction angle This indicates the swing direction of the extension rod 41 in the plane. With the center of the sleeve as a reference, 0° corresponds to the positive x-axis direction, and 90° corresponds to the positive y-axis direction.

[0051] Since the first safety valve 53 and the second safety valve 54 are located on both sides of the sleeve 20, assuming the first safety valve 53 is located at 0° and the second safety valve 54 is located at 180°, the swing direction angle can be used as a reference. The value selectively opens either the first safety valve 53 or the second safety valve 54. If the swing direction angle... If the swing is within the range of 0°±45° or 180°±45°, meaning the swing is mainly along the x-axis, then the safety valve opens in the opposite direction of the swing. For example: when When the pressure is greater than 0, and the swing is in the positive x-axis direction, the second safety valve 54 opens to release gas and reduce the positive pressure; when... When the pressure is less than 0, and the swing is in the negative x-axis direction, the first safety valve 53 is opened to release gas and reduce the pressure in the positive direction.

[0052] If the swing direction angle Within the range of 90°±45° or 270°±45°, the swing is mainly along the y-axis. However, since the safety valves are only installed on both sides of the sleeve rod 50, two safety valves can be opened simultaneously to uniformly exhaust air and balance the influence of the y-axis.

[0053] Furthermore, based on the total radial offset and combination and The opening times of the first safety valve 53 and the second safety valve 54 are calculated based on the ratio.

[0054] The opening time FT1 of the first safety valve 53 is:

[0055] The opening time FT2 of the second safety valve 54 is:

[0056] In this embodiment, 3mm diameter vent holes are located on both sides of the sleeve rod 50 to release gas accumulated inside the sleeve rod, which may cause slight oscillation of the extension rod 41. By controlling the venting of the safety valves, the internal gas pressure of the sleeve rod can be adjusted, reducing the lateral force of the gas on the extension rod, thereby stabilizing the movement of the extension rod. Specifically, the first safety valve 53 and the second safety valve 54 are respectively installed on the vent holes on both sides of the sleeve rod 50. Based on the oscillation detection results, it is determined which safety valve to open and for how long.

[0057] Example 3 Based on one or more of the above embodiments, refer to Figure 6 As shown in the figure, this embodiment proposes a control method for a piston-type accumulator position detection mechanism, including the following steps: S1: Set zero point and calibration; When piston 40 is in the fully discharged state, piston 40 is against the first end cover 20, and the volume of oil chamber 11 is at its minimum, the position of magnetic ring is set as the zero point of displacement, and the output signal of displacement sensor is calibrated as the zero point signal. When piston 40 is fully filled with oil and presses against the second end cap 30, and the oil chamber 11 is at its maximum volume, the position of magnetic ring 43 is recorded as the maximum displacement L. max The output signal of displacement sensor 51 is marked as a full-scale signal. Input the propagation velocity V of the torsional stress wave in the waveguide wire, and set parameters such as the sensitivity A of the Hall sensor.

[0058] S2: Real-time piston position detection; Displacement signal acquisition: A displacement sensor (such as a magnetostrictive sensor) continuously monitors changes in the magnetic field generated by the magnetic ring and outputs a signal related to the piston position. This is achieved by measuring the time interval between the current pulse emission and the stress wave reception by the pickup. ; calculate the absolute position of the piston. ; Position change calculation: As needed, calculate the position change of the piston over a period of time as follows:

[0059] Where Y1 and Y2 are the absolute positions at time points t1 and t2, respectively. When, it indicates that the piston moves towards the gas chamber; when When , it indicates that the piston is moving towards the oil chamber.

[0060] S3: Swing detection and offset calculation; Four Hall sensors are evenly arranged circumferentially on the inner wall of the sleeve, with angular positions of 0°, 90°, 180° and 270° respectively. They detect the radial magnetic field changes of the magnetic ring in real time, output signals S1, S2, S3 and S4, and calculate the offset of the swing center, the total radial offset and the swing direction angle.

[0061] S4: Safety valve control decision; If the swing direction angle Within the range of 0°±45° or 180°±45°, when When the pressure is greater than 0, and the swing is in the positive x-axis direction, the second safety valve 54 opens to release gas and reduce the positive pressure; when... When the pressure is less than 0, when the swing is in the negative x-axis direction, the first safety valve 53 is opened to release gas and reduce the pressure in the positive direction. If the swing direction angle Within the range of 90°±45° or 270°±45°, i.e., the swing is mainly along the y-axis, while the first safety valve 53 and the second safety valve 54 are opened to uniformly exhaust gas.

[0062] In this embodiment, the displacement sensor measures the piston position based on the propagation time of the torsional stress wave in the waveguide wire. The magnetic ring moves with the piston, generating a change in the magnetic field. The sensor calculates the time interval between the transmission and reception of the stress wave. ; using formula The absolute position of the piston is obtained. No physical contact is required, avoiding the mechanical fatigue problem of traditional wire-type sensors.

[0063] Because the extension rod may experience slight oscillations within the air chamber, affecting the alignment accuracy between the magnetic ring and the magnetic rod, a Hall sensor array arranged on the inner wall of the sleeve is used to detect changes in the radial magnetic field of the magnetic ring. The calculated offset... and This reflects the magnitude and direction of the swing. Subsequently, by venting air through the safety valves on both sides of the control rod, the internal air pressure of the control rod is adjusted, generating a reaction force to counteract the swing. The opening time and direction of the safety valves are dynamically adjusted based on the swing direction angle φ and the offset ratio to ensure the accuracy and efficiency of the compensation.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A piston-type accumulator position detection mechanism, comprising a cylinder (10), a first end cap (20), a second end cap (30), a piston (40), an oil chamber (11), and an air chamber (12), characterized in that, The sleeve (50) is fixedly connected to the second end cap (30); A displacement sensor (51) is mounted on the top of the sleeve (50); The magnetic rod (52) is connected to the displacement sensor (51) and passes through the inside of the sleeve rod (50); An extension rod (41) is disposed at one end of the piston (40) near the second end cap (30) and reciprocates with the piston (40). The extension rod (41) has a hollow cavity (42), and the magnetic rod (52) is located inside the hollow cavity (42). A magnetic ring (43) is fixed to the end of the extension rod (41); The displacement sensor (51) detects the piston position by detecting the change in the magnetic field of the magnetic ring (43).

2. The piston-type accumulator position detection mechanism according to claim 1, characterized in that, The extension rod (41) is connected to the piston (40) by a thread, and the magnetic ring (43) is installed at the end of the extension rod (41) by a gasket.

3. The piston-type accumulator position detection mechanism according to claim 1, characterized in that, Also includes: At least one Hall sensor is disposed on the inner wall of the sleeve (50) for detecting changes in the radial magnetic field of the magnetic ring (43). The Hall sensors are four in number and are evenly arranged circumferentially on the inner wall of the sleeve (50), with angular positions of 0°, 90°, 180° and 270° respectively.

4. The piston-type accumulator position detection mechanism according to claim 3, characterized in that, The Hall sensor calculates the swing center offset, total radial offset, and swing direction angle of the extension rod (41).

5. The piston-type accumulator position detection mechanism according to claim 1, characterized in that, Also includes: At least two vent holes are provided on the side wall of the sleeve (50); The first safety valve (53) and the second safety valve (54) are respectively installed on one of the exhaust ports; The exhaust control unit controls the opening state and opening time of the safety valve based on the swing detection results.

6. The piston-type accumulator position detection mechanism according to claim 5, characterized in that, The exhaust control unit includes: When the swing direction angle is within the range of 0°±45° or 180°±45°, the first safety valve (53) or the second safety valve (54) is opened according to the sign of the offset. When the swing direction angle is within the range of 90°±45° or 270°±45°, the first safety valve (53) and the second safety valve (54) are opened simultaneously.

7. The piston-type accumulator position detection mechanism according to claim 6, characterized in that, When the swing direction angle is within the range of 0°±45° or 180°±45°, calculate the opening time of the first safety valve (53) and the second safety valve (54).

8. A control method for a piston accumulator position detection mechanism, comprising the piston accumulator position detection mechanism as described in claim 1, characterized in that, Includes the following steps: S1: Set zero point and calibration; When the piston (40) is in a fully discharged state and a fully filled state, the zero point signal and full scale signal of the displacement sensor (51) are calibrated respectively. S2: Real-time piston position detection; The absolute position and position change of the piston are calculated by measuring the magnetic field change of the magnetic ring (43) using the displacement sensor (51); S3: Swing detection and offset calculation; The radial magnetic field change of the magnetic ring (43) is detected by the Hall sensor array, and the offset of the swing center, the total radial offset and the swing direction angle are calculated. S4 safety valve control decision; Based on the swing direction angle and offset, the opening state and opening time of the first safety valve (53) and the second safety valve (54) are controlled.

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