Three-chamber cylinder electrostatic hydraulic actuator system, control method and medium for engineering machinery

Abstract

The present invention provides a three-chamber electrostatic hydraulic actuator system, a control method and a medium for engineering machinery, and relates to the technical field of electrostatic hydraulic actuators. Among them, the three-chamber electrostatic hydraulic actuator system comprises a three-chamber cylinder (extending chamber, retracting chamber, energy storage chamber), a locking switch valve, a bidirectional hydraulic pump / motor, a bidirectional electric generator, an external accumulator, a first overflow valve, a first fixed pressure reducing valve and a plurality of pressure sensors. The maximum effective volume of the extending chamber is equal to that of the retracting chamber, and the external accumulator stores energy when the three-chamber cylinder is shortened and releases energy when it is extended. The control method includes: calculating a first pressure threshold according to the engineering machinery parameters and the external accumulator pressure model, adjusting the first overflow valve and the first fixed pressure reducing valve accordingly, thereby adjusting the pressure of the hydraulic oil in the energy storage chamber, so that the minimum supporting force of the three-chamber cylinder can be balanced with the boom of the engineering machinery, reducing the driving force of the actuator, and increasing the driving speed.

Description

Technical Field

[0001] The present invention relates to the technical field of electrostatic hydraulic actuators, and in particular to a three-chamber electrostatic hydraulic actuator system, a control method and a medium for engineering machinery. Background Art

[0002] In the field of engineering machinery and industrial production, hydraulic cylinders are widely used as linear drive actuators in hydraulic systems because of their advantages such as high power density, stepless speed regulation and self-lubrication. However, traditional open hydraulic systems have many problems, such as overflow loss, throttling loss and loss of hydraulic oil along the pipeline, which lead to low efficiency of hydraulic systems. The emergence of closed pump control systems, which drive the actuator hydraulic cylinder by volume through hydraulic pumps, significantly reduces throttling losses and reduces system energy consumption. However, in closed pump control systems with asymmetric hydraulic cylinders as actuators, it is difficult to balance the flow difference between the two chambers of the hydraulic cylinder during driving. The asymmetric flow circulates in the closed oil circuit, affecting the normal operation of the system. Although the closed system using symmetrical hydraulic cylinders as actuators does not need to consider flow compensation, it is difficult to realize its layout due to the compact structure and limited space of engineering machinery.

[0003] In addition, the existing electrostatic hydraulic actuators have low power and bulky structure, which makes it difficult to meet the needs of engineering machinery with high power and limited layout space. These problems have prompted the development of this patented technology, which aims to solve the above difficulties and improve the performance of the hydraulic system of engineering machinery. Summary of the invention

[0004] The present invention provides a three-chamber cylinder electrostatic hydraulic actuator system, a control method and a medium for engineering machinery to improve at least one of the above-mentioned technical problems.

[0005] In the first aspect, the present invention provides a control method for a three-chamber cylinder electrostatic hydraulic actuator system of an engineering machinery. The three-chamber cylinder electrostatic hydraulic actuator system comprises: a three-chamber cylinder provided with an extension chamber, a retraction chamber and an energy storage chamber, a first locking switch valve connected to the extension chamber by a pipeline, a second locking switch valve connected to the retraction chamber by a pipeline, a bidirectional hydraulic pump / motor with a first oil circuit interface connected to the first locking switch valve and a second oil circuit interface connected to the second locking switch valve, a bidirectional electric generator transmission-connected to the bidirectional hydraulic pump / motor, an external accumulator connected to the energy storage chamber by a pipeline, a first overflow valve and a first fixed-value pressure reducing valve connected to the external accumulator by a pipeline, a first pressure sensor connected to the first oil circuit interface, a second pressure sensor connected to the second oil circuit interface, and a third pressure sensor connected to the external accumulator.

[0006] The liquid inlet of the first overflow valve is connected to the external accumulator for pressure relief. The liquid outlet of the first fixed value pressure reducing valve is connected to the external accumulator for pressurization.

[0007] The maximum effective volumes of the extension chamber and the retraction chamber of the three-chamber cylinder are equal. The external accumulator is configured to store hydraulic energy when the three-chamber cylinder is shortened and release hydraulic energy when the three-chamber cylinder is extended.

[0008] In an optional embodiment, the three-chamber electrostatic hydraulic actuator system also includes: an internal accumulator, a second overflow valve for discharging the hydraulic oil in the extension chamber to the internal accumulator, a first one-way valve for discharging the hydraulic oil in the internal accumulator to the first oil circuit interface, a third overflow valve for discharging the hydraulic oil in the retraction chamber to the internal accumulator, and a second one-way valve for discharging the hydraulic oil in the internal accumulator to the second oil circuit interface.

[0009] In an optional embodiment, the three-chamber electrostatic hydraulic actuator system further includes a load-relief switch valve capable of connecting the extension chamber and the retraction chamber, and a fourth pressure sensor and an oil replenishment interface coupled to the internal accumulator.

[0010] In an optional embodiment, the three-chamber cylinder electrostatic hydraulic actuator includes a cylinder barrel and an extension rod telescopically engaged with the cylinder barrel.

[0011] The cylinder comprises a first tube wall and a second tube wall sleeved on the first tube wall. A first cavity is formed in the first tube wall. A second cavity is formed between the first tube wall and the second tube wall.

[0012] At least part of the extension rod is constructed as a tubular geometric body and is embedded in the second cavity. The extension cavity is formed between the extension rod and the first cavity. The extension rod is constructed to be able to separate the second cavity into the retraction cavity and the energy storage cavity. The change in the cavity size of the retraction cavity is opposite to the change in the cavity size of the extension cavity. The change in the cavity size of the energy storage cavity is the same as the change in the cavity size of the extension cavity.

[0013] The control method comprises:

[0014] A first pressure threshold of the external accumulator is calculated according to the parameters of the engineering machinery and in combination with a pressure model of the external accumulator.

[0015] The thresholds of the first relief valve and the first fixed-value pressure reducing valve are adjusted according to the first pressure threshold.

[0016] Adjust the boom to its initial position.

[0017] A first pressure of the external accumulator is obtained, and it is determined whether the first pressure is lower than a first pressure threshold.

[0018] When it is determined that the first pressure is lower than the first pressure threshold, the first fixed value pressure reducing valve is pressurized to charge the external accumulator until the first pressure is not less than the first pressure threshold.

[0019] In an optional implementation, the pressure model of the external accumulator is:

[0020]

[0021]

[0022]

[0023] In the formula, The initial external accumulator adjustment pressure is the external accumulator pressure when the boom is lowered to the lowest position. is the total mass of the engineering machinery boom, is the acceleration due to gravity, is the area of ​​the energy storage chamber, It is the regulating pressure of the external accumulator when the three-chamber cylinder is not in the initial position, that is, when the boom is lowered to the lowest position. is the total volume of the external accumulator, is the initial position, i.e. the volume of oil in the external accumulator when the boom is lowered to the lowest position, is the elongation of the three-chamber cylinder compared to the initial position, Charge pressure for external accumulator, is the volume of the external accumulator, For the maximum working pressure, is the gas volume of the external accumulator at the highest pressure, For the minimum working pressure, is the volume of gas in the external accumulator at the lowest pressure, is the polytropic index. When the gas is under isothermal working conditions =1, is a constant.

[0024] In an optional implementation, the control method further comprises:

[0025] When the engineering machinery is in a positive load condition, that is, the load pressure during the lifting process of the engineering machinery boom hinders the lifting of the boom, or the load pressure during the lowering process of the engineering machinery boom hinders the lowering of the boom: obtain the pressure of each chamber of the three-chamber cylinder, and determine that the pressure of the extension chamber and the retraction chamber is less than the second pressure threshold.

[0026] When it is determined that the pressures of the extension chamber and the retraction chamber are less than a second pressure threshold, a manipulation action is performed according to a control signal, and the pressures of the various chambers are monitored in real time.

[0027] When it is determined that the pressures of the extension chamber and the retraction chamber are not less than the second pressure threshold, the driving is stopped until the pressure is reduced to less than the second pressure threshold through the relief valve.

[0028] In an optional implementation, the control method further comprises:

[0029] When the engineering machinery is in a negative load condition, that is, the load pressure during the lifting process of the engineering machinery boom promotes the lifting of the boom, or the load pressure during the lowering process of the engineering machinery boom promotes the lowering of the boom: obtain the first pressure of the external energy storage chamber, and determine whether the change rate of the first pressure is greater than the first change rate threshold.

[0030] When it is determined that the change speed of the first pressure is greater than a first change speed threshold, the bidirectional hydraulic pump / motor is switched to motor mode, and the bidirectional electric generator is switched to generator mode to perform electrical energy recovery.

[0031] In an optional implementation, the control method further comprises:

[0032] The pressure of each chamber of the three-chamber cylinder is obtained, and it is determined that the pressure of the extension chamber and the retraction chamber is less than a third pressure threshold.

[0033] When it is determined that the pressures in the extension chamber and the retraction chamber are not less than a third pressure threshold, the unloading switch valve is opened.

[0034] In a second aspect, the present invention provides a three-chamber cylinder electrostatic hydraulic actuator system for engineering machinery, comprising a processor, a memory, and a computer program stored in the memory. The computer program can be executed by the processor to implement a control method for a three-chamber cylinder electrostatic hydraulic actuator system for engineering machinery as described in any paragraph of the first aspect.

[0035] In a third aspect, the present invention provides a computer-readable storage medium. The computer-readable storage medium includes a stored computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located is controlled to execute a control method for a three-chamber electrostatic hydraulic actuator system of an engineering machinery as described in any paragraph of the first aspect.

[0036] By adopting the above technical solution, the present invention can achieve the following technical effects:

[0037] The control method of the three-chamber cylinder electrostatic hydraulic actuator system of an engineering machinery of the present invention can significantly improve the energy efficiency and operating efficiency of the engineering machinery. The system achieves flow symmetry of the asymmetric cylinder by accurately controlling the extension chamber, retraction chamber and energy storage chamber of the three-chamber cylinder, effectively solving the flow matching problem in the traditional closed system.

[0038] In addition, the closed pump control design adopted by the system greatly reduces overflow loss and throttling loss, and improves energy efficiency to more than 70%, which is a significant energy saving advantage compared to the 35% energy efficiency of traditional systems. In terms of structural design, by making the extension cavity and the retraction cavity area equal, the system achieves a more compact layout without sacrificing performance, adapting to the challenge of limited space in construction machinery.

[0039] Overall, this patented technology, through its innovative design, not only improves the reliability and efficiency of operations, but also optimizes the overall performance of the system, bringing a new type of efficient and energy-saving electrostatic hydraulic actuator system solution to the field of construction machinery. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the specific implementation methods of the present invention. It should be understood that the following drawings only show certain specific implementation methods of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 It is an axonometric view of a three-chamber electrostatic hydraulic actuator system.

[0042] Figure 2 It is a half-section diagram of a three-chamber cylinder.

[0043] Markings in the figure: 1-extension chamber, 2-energy storage chamber, 3-fixed plate, 4-three-chamber cylinder, 5-first one-way valve, 6-retraction chamber, 7-integrated valve block, 8-internal accumulator, 9-third overflow valve, 10-second overflow valve, 11-second one-way valve, 12-second locking switch valve, 13-first locking switch valve, 14-unloading switch valve, 15-bidirectional hydraulic pump / motor, 16-bidirectional electric generator. DETAILED DESCRIPTION

[0044] The technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0045] Example 1, please refer to Figure 1 to Figure 2The first embodiment of the present invention provides a control method for a three-chamber cylinder electrostatic hydraulic actuator system of an engineering machinery. The three-chamber cylinder electrostatic hydraulic actuator system includes: a three-chamber cylinder 4 provided with an extension chamber 1, a retraction chamber 6 and an energy storage chamber 2, a first locking switch valve 13 connected to the extension chamber 1 by a pipeline, a second locking switch valve 12 connected to the retraction chamber 6 by a pipeline, a bidirectional hydraulic pump / motor 15 whose first oil circuit interface is connected to the first locking switch valve 13 and whose second oil circuit interface is connected to the second locking switch valve 12, a bidirectional electric generator 16 connected to the bidirectional hydraulic pump / motor 15 by transmission, an external accumulator connected to the energy storage chamber 2 by a pipeline, a first overflow valve and a first fixed pressure reducing valve connected to the external accumulator by a pipeline, a first pressure sensor connected to the first oil circuit interface, a second pressure sensor connected to the second oil circuit interface, and a third pressure sensor connected to the external accumulator.

[0046] The liquid inlet of the first overflow valve is connected to the external accumulator for pressure relief. The liquid outlet of the first fixed value pressure reducing valve is connected to the external accumulator for pressurization.

[0047] The maximum effective volumes of the extension chamber 1 and the retraction chamber 6 of the three-chamber cylinder 4 are equal. The external accumulator is configured to store hydraulic energy when the three-chamber cylinder 4 is shortened and release hydraulic energy when the three-chamber cylinder 4 is extended.

[0048] On the basis of the above embodiment, in an optional embodiment of the present invention, the three-chamber cylinder electrostatic hydraulic actuator system further includes: an internal accumulator 8, a second overflow valve 10 for discharging the hydraulic oil of the extension chamber 1 to the internal accumulator 8, a first one-way valve 5 for discharging the hydraulic oil of the internal accumulator 8 to the first oil circuit interface, a third overflow valve 9 for discharging the hydraulic oil of the retracting chamber 6 to the internal accumulator 8, and a second one-way valve 11 for discharging the hydraulic oil of the internal accumulator 8 to the second oil circuit interface. Preferably, the three-chamber cylinder electrostatic hydraulic actuator system further includes a load unloading switch valve 14 capable of connecting the extension chamber 1 and the retracting chamber 6, and a fourth pressure sensor and an oil replenishing interface connected to the internal accumulator 8.

[0049] like Figure 1 As shown, the specific scheme of the three-chamber cylinder electrostatic hydraulic actuator system is as follows: the bidirectional electric generator 16 is connected and matched with the bidirectional hydraulic pump / motor 15 through a bell-shaped cover, and the rotor of the bidirectional electric generator 16 is an internal spline that matches the external spline of the protruding shaft of the bidirectional hydraulic pump / motor 15. The bidirectional hydraulic pump / motor 15 is driven to work by the rotation of the bidirectional electric generator 16. The bidirectional electric generator 16 and the bell-shaped cover, and the bell-shaped cover and the bidirectional hydraulic pump / motor 15 are all connected by bolts. And the bidirectional hydraulic pump / motor 15 is directly fixed on the bell-shaped cover by bolts with the bell-shaped cover.

[0050] The integrated valve block 7 is equipped with an unloading switch valve 14, a first locking switch valve 13, a second locking switch valve 12, a first check valve 5, a second check valve 11, a second relief valve 10, a third relief valve 9, and an internal accumulator 8. The integrated valve block 7 is provided with corresponding cartridge valve slots for each cartridge valve, so that the integrated valve block 7 and the cartridge valves are closely matched. Compared with the traditional closed pump control system, the system integration is improved.

[0051] The integrated valve block 7 is connected to the oil inlet and outlet of the bidirectional hydraulic pump / motor 15 through the oil pipe, and is connected to the oil port of the extension chamber 1 and the oil port of the retraction chamber 6 of the three-chamber cylinder 4. A closed loop system is formed, which effectively reduces overflow loss and throttling loss compared to the open loop system of the traditional hydraulic cylinder, and improves the energy efficiency of the system. The oil pipe uses a hydraulic hard pipe, which is more reliable and has a longer life than a hydraulic hose.

[0052] Meanwhile, three pressure measuring holes and one oil replenishing interface are provided on the integrated valve block 7. The three pressure measuring holes are used to install the first pressure sensor, the second pressure sensor and the fourth pressure sensor respectively, so as to collect and feedback the oil inlet and outlet pressures of the bidirectional hydraulic pump / motor 15, the two-chamber pressure of the three-chamber cylinder 4 and the internal pressure of the internal accumulator 8. Before using the three-chamber cylinder electrostatic hydraulic actuator for the first time, it is necessary to replenish the oil for the system through the reserved oil replenishing interface.

[0053] The above-mentioned bidirectional electric generator 16, bell housing, integrated valve block 7 are connected to the fixing plate 3 by bolts, and the fixing plate 3 is fixed to the connecting block designed for the outer shell of the three-chamber cylinder 4 by bolts. The bidirectional hydraulic pump / motor 15 is fixed to the bell housing after being connected to the bell housing by bolts, and is fixed to the fixing plate 3 by the bell housing, and the bidirectional hydraulic pump / motor 15 is no longer in contact with the fixing plate 3.

[0054] It is fixed in the system by connecting with the threaded oil ports of the bidirectional hydraulic pump / motor 15, the integrated valve block 7 and the three-chamber cylinder 4. Through the customized design of the size and configuration of the hard pipe, the length of the system oil pipe is shortened, the loss along the system is reduced, and the system integration is improved.

[0055] Based on the above embodiments, in an optional embodiment of the present invention, as Figure 2 As shown, the three-chamber cylinder electrostatic hydraulic actuator includes a cylinder barrel and an extension rod which is telescopically and movably connected to the cylinder barrel.

[0056] The cylinder comprises a first tube wall and a second tube wall sleeved on the first tube wall. A first cavity is formed in the first tube wall. A second cavity is formed between the first tube wall and the second tube wall.

[0057] At least part of the extension rod is constructed as a tubular geometric body and is embedded in the second cavity. The extension cavity 1 is formed between the extension rod and the first cavity. The extension rod is configured to separate the second cavity into the retraction cavity 6 and the energy storage cavity 2. The change in the cavity size of the retraction cavity 6 is opposite to the change in the cavity size of the extension cavity 1. The change in the cavity size of the energy storage cavity 2 is the same as the change in the cavity size of the extension cavity 1.

[0058] Preferably, the inner diameter of the second tube wall is 160 mm. The outer diameter of the extension rod is 125 mm. The inner diameter of the extension rod is 100 mm. The cross-sectional area of ​​the extension chamber 1 is 7854 square millimeters. The cross-sectional area of ​​the retracted chamber 6 is 7835 square millimeters.

[0059] Specifically, Figure 2 As shown, the interior of the three-chamber cylinder 4 is divided into three chambers, namely the extension chamber 1, the retraction chamber 6, and the energy storage chamber 2. Through size design, the maximum effective volume of the extension chamber 1 and the retraction chamber 6 is designed to be equal. It effectively solves the flow difference problem caused by the different volumes of the two chambers of the asymmetric hydraulic cylinder in the closed pump control system. Compared with the traditional hydraulic cylinder, the three-chamber cylinder 4 structure adds an energy storage chamber 2, which can be connected to the external accumulator through the oil port of the energy storage chamber 2, thereby assisting the extension of the three-chamber cylinder 4. By designing the external accumulator pressure to balance the boom gravity, the external fusion large load can be effectively recovered and reused.

[0060] The three-chamber electrostatic hydraulic actuator is mounted on construction machinery as a whole, replacing the traditional hydraulic cylinder. The cylinder bottom earrings and cylinder top earrings of the three-chamber electrostatic hydraulic actuator are hinged to the pin shaft of the construction machinery. The operation process of the construction machinery is realized by extending and retracting the three-chamber electrostatic hydraulic actuator.

[0061] Based on the above embodiment, in an optional embodiment of the present invention, the control method includes:

[0062] A1. Calculate the first pressure threshold of the external accumulator based on the parameters of the engineering machinery and the pressure model of the external accumulator. Preferably, the pressure model of the external accumulator is:

[0063]

[0064]

[0065]

[0066] In the formula, The initial external accumulator adjustment pressure is the external accumulator pressure when the boom is lowered to the lowest position. is the total mass of the engineering machinery boom, is the acceleration due to gravity, is the area of ​​the energy storage chamber, It is the regulating pressure of the external accumulator when the three-chamber cylinder is not in the initial position, that is, when the boom is lowered to the lowest position. is the total volume of the external accumulator, is the initial position, i.e. the volume of oil in the external accumulator when the boom is lowered to the lowest position, is the elongation of the three-chamber cylinder compared to the initial position, Charge pressure for external accumulator, is the volume of the external accumulator, For the maximum working pressure, is the gas volume of the external accumulator at the highest pressure, For the minimum working pressure, is the volume of gas in the external accumulator at the lowest pressure, is the polytropic index. When the gas is under isothermal working conditions =1, is a constant.

[0067] A2. Adjust the thresholds of the first relief valve and the first fixed value pressure reducing valve according to the first pressure threshold.

[0068] A3. Adjust the boom to an initial position. Preferably, the initial position is when the boom is at its lowest position.

[0069] A4. Obtain a first pressure of the external accumulator, and determine whether the first pressure is lower than a first pressure threshold.

[0070] A5. When it is determined that the first pressure is lower than the first pressure threshold, pressurize the first fixed value pressure reducing valve to charge the external accumulator until the first pressure is not less than the first pressure threshold.

[0071] In this embodiment, the first overflow valve and the first fixed-value pressure reducing valve are only used when adjusting the pressure of the external accumulator for the first time. During the subsequent operation of the engineering machinery, the hydraulic oil in the external accumulator is not adjusted, so that the external accumulator and the energy storage chamber 2 are equivalent to a spring to assist in supporting part of the force.

[0072] Specifically, when adjusting the pressure of the external accumulator for the first time, first put the engineering machinery in a no-load condition, that is, there is no working material on the boom of the engineering machinery, including in the bucket, and only the boom itself is lifted and lowered. Then, the first pressure is calculated according to the pressure model of the external accumulator. When the internal pressure of the external accumulator is higher than the pressure, the overflow valve is used to adjust the pressure, and the external accumulator is connected to the oil inlet of the overflow valve for overflow pressure adjustment. When the pressure of the external accumulator drops to the set pressure, the overflow valve is automatically closed; when the internal pressure of the external accumulator is lower than the pressure, a fixed-value pressure reducing valve is used for charging, and the external accumulator is connected to the outlet of the fixed-value pressure reducing valve, and the oil filling and pressure adjustment are performed through external oil supply. When the pressure of the external accumulator reaches the set pressure, the fixed-value pressure reducing valve is automatically closed. The force of the energy storage chamber 2 is matched with the gravity of the boom to achieve the effect of self-weight balance of the engineering machinery boom, that is, when the boom falls to the lowest position, the force of the energy storage chamber 2 of the three-chamber cylinder 4 is equal to the gravity of the boom.

[0073] In other embodiments, the first pressure can be adjusted in real time during the operation of the engineering machinery to always maintain it at the first pressure threshold, so that the driving of the bidirectional electric generator 16 is more labor-saving and fast, and the present invention does not make specific limitations on this.

[0074] The operator controls the motor to rotate forward or reverse, thereby driving the system hydraulic oil to transmit, driving the three-chamber cylinder 4 to drive the boom of the construction machinery to lift and lower. Thanks to the pressure of the external accumulator and the energy storage chamber 2 balancing most of the boom's gravity, the system energy efficiency during the operation is improved. In addition, the internal accumulator 8 provides real-time supplementary pressure inside the system to prevent air suction during the operation.

[0075] Based on the above embodiment, in an optional embodiment of the present invention, the control method further comprises:

[0076] B1. When the engineering machinery is in a positive load condition, that is, when the load pressure during the lifting process of the engineering machinery boom hinders the lifting of the boom, or when the load pressure during the lowering process of the engineering machinery boom hinders the lowering of the boom: obtain the pressure of each chamber of the three-chamber cylinder 4, and determine that the pressure of the extension chamber 1 and the retraction chamber 6 is less than the second pressure threshold.

[0077] B2. When it is determined that the pressures of the extension chamber 1 and the retraction chamber 6 are less than a second pressure threshold, a control action is performed according to a control signal, and the pressures of each chamber are monitored in real time.

[0078] Specifically, when the boom of the construction machinery is lifted, the gravity of the boom and the materials in the bucket prevent the three-chamber cylinder 4 from extending. Or when the boom of the construction machinery is lowered, there is work material under the bucket that needs to be compacted by the boom. At this time, the system performs energy-consuming operations, and the operation steps are as follows: 1. The system obtains the pressure of each chamber of the three-chamber cylinder 4. 2. When the pressure of the extension chamber 1 or the retraction chamber 6 is less than the second pressure threshold. 3. The system performs normal driving operations, and the driver drives the motor forward and reverse through the operating handle to lift or lower. 4. The energy storage chamber 2 performs auxiliary support in real time. After adjusting the pressure of the external accumulator in the front (i.e., steps A1 to A5), the force output by the energy storage chamber 2 of the boom at the lowest posture is approximately equal to the gravity of the boom itself, that is, the external accumulator and the energy storage chamber 2 work together to always provide an action to assist support and reduce the driving power. 5. When the boom is lifted to a suitable position or the extrusion of the work material is completed, the operating handle is released to complete the working condition operation.

[0079] B3. When it is determined that the pressures of the extension chamber 1 and the retraction chamber 6 are not less than the second pressure threshold, the driving is stopped until the pressure is reduced to less than the second pressure threshold through the overflow valve.

[0080] Specifically, when the boom of the engineering machinery is lifted beyond the appropriate position under the B2 working condition, or the driver does not release the handle after the extrusion of the working material is completed, causing the boom of the engineering machinery to be lifted to a high position, or the boom is continuously squeezed downward to cause the front of the engineering machinery to tilt up, the step B3 is advanced. At this time, the system operation steps are as follows: 1. The system obtains the pressure of each chamber of the three-chamber cylinder 4. 2. At this time, the pressure of the three-chamber cylinder 4 will continue to rise, when the pressure of the extension chamber 1 or the retraction chamber 6 is greater than the second pressure threshold. 3. At this time, the second overflow valve 10 and the third of the system play an overload protection role. 4. At the same time, the extension chamber 1 or the retraction chamber 6 is no longer driven, and the energy storage chamber 2 plays a supporting role. At this time, because of the overload, the extension chamber 1 / retraction chamber 6 overflows, so only the energy storage chamber 2 supports, but the overflow is only carried out when overloaded, and the pressure is relatively high, so it can also be understood that the extension chamber 1 and the energy storage chamber 2 support together. In other words, the pressure of the extension chamber 1 is relatively high at this time, but it is overflowing to reduce pressure, while the energy storage chamber 2 maintains a constant pressure support. 5. When it is detected that the system pressure drops to a second pressure threshold, the extending chamber 1 or the retracting chamber 6 can continue to be driven.

[0081] Based on the above embodiment, in an optional embodiment of the present invention, the control method further comprises:

[0082] C1. When the engineering machinery is in a negative load condition, that is, when the load pressure during the lifting process of the engineering machinery boom promotes the lifting of the boom, or when the load pressure during the lowering process of the engineering machinery boom promotes the lowering of the boom: obtain the first pressure of the external energy storage chamber 2, and determine whether the change rate of the first pressure is greater than the first change rate threshold.

[0083] C2. When it is determined that the change speed of the first pressure is greater than a first change speed threshold, the bidirectional hydraulic pump / motor 15 switches to motor mode, and the bidirectional electric generator 16 switches to generator mode to perform electrical energy recovery.

[0084] Specifically, the negative load condition is: when the engineering machine boom supports the front body to lift up, the front body needs to be lowered after lifting, that is, the boom as a whole performs a lifting operation. The gravity of the front body promotes the extension of the three-chamber cylinder 4. Or when the engineering machine boom is lowered, the overall mass of the boom and the working materials in the bucket promote the retraction of the three-chamber cylinder 4.

[0085] At this time, the system performs energy recovery, and the driver drives the motor to rotate forward and reverse by operating the handle to lift or lower the boom. When the boom operating speed is too fast or the load impact is too large, the system operation steps are as follows: 1. The system detects that the pressure in the energy storage chamber 2 increases too fast, and the pressure change rate is greater than the first change rate threshold. 2. The external accumulator performs fusion large load potential energy recovery. 3. Combine the bidirectional hydraulic pump / motor 15 and the bidirectional electric generator 16 to perform electrical energy recovery for slowly changing long loads other than potential energy recovery. 4. The internal pressure in the extension chamber 1 or the retraction chamber 6 will drive the motor to perform electrical energy recovery, and the bidirectional hydraulic pump / motor 15 will adjust its own displacement according to the system flow rate to maximize the efficiency of electrical energy recovery. Combine the two energy recovery methods for coordinated energy recovery. Adjusting one's own displacement belongs to the prior art, and the present invention will not go into details.

[0086] Based on the above embodiment, in an optional embodiment of the present invention, the control method further comprises:

[0087] C1. Obtain the pressure of each chamber of the three-chamber cylinder 4, and determine whether the pressure of the extension chamber 1 and the retraction chamber 6 is less than a third pressure threshold.

[0088] C2. When it is determined that the pressures of the extension chamber 1 and the retraction chamber 6 are not less than a third pressure threshold, the unloading switch valve 14 is opened.

[0089] Specifically, when the engineering machinery is in a hovering condition, that is, the boom needs to be fixed at a certain position, at this time, the first locking switch valve 13 and the second locking switch valve 12 are in a closed state.

[0090] The system operation steps are as follows: 1. The system collects and obtains the pressure of each chamber of the three-chamber cylinder 4 in real time during the hovering process. 2. When the engineering machinery is subjected to a large external load, the pressure of the extension chamber 1 or the retraction chamber 6 of the three-chamber cylinder 4 is greater than the second pressure threshold. 3. The locking switch valve is opened, and the overload protection function is played through the second relief valve 10 and the third relief valve 9. 4. When the system pressure continues to increase, the pressure of the extension chamber 1 or the retraction chamber 6 is greater than the third pressure threshold. The unloading switch valve 14 is opened, connecting the extension chamber 1 or the retraction chamber 6 to enable the system to perform unloading protection.

[0091] It should be noted that the first pressure threshold, the second pressure threshold, the third pressure threshold and the first change speed threshold can be set by those skilled in the art according to the actual conditions of the engineering machinery, and the present invention does not make any specific limitation on this.

[0092] The control method of any of the above working conditions is characterized by closed-loop control of the operating handle, pressure sensor, motor, and hydraulic pump displacement in the system. The motor speed control adopts the PID closed-loop control inside the electronic control system. The control of the hydraulic pump displacement adopts fuzzy adaptive PID control according to the input signal of the electronic control handle.

[0093] The control method of the three-chamber cylinder 4 electrostatic hydraulic actuator system of the engineering machinery of the present invention can significantly improve the energy efficiency and working efficiency of the engineering machinery. The system realizes the flow symmetry of the asymmetric cylinder by accurately controlling the extension chamber 1, the retraction chamber 6 and the energy storage chamber 2 of the three-chamber cylinder 4, and effectively solves the flow matching problem in the traditional closed system.

[0094] In addition, the closed pump control design adopted by the system greatly reduces overflow loss and throttling loss, and improves energy efficiency to more than 70%, which is a significant energy saving advantage compared to the 35% energy efficiency of traditional systems. In terms of structural design, by making the extension chamber 1 and the retraction chamber 6 equal in area, the system achieves a more compact layout without sacrificing performance, adapting to the challenge of limited space in construction machinery.

[0095] Overall, this patented technology, through its innovative design, not only improves the reliability and efficiency of operations, but also optimizes the overall performance of the system, bringing a new type of efficient and energy-saving electrostatic hydraulic actuator system solution to the field of construction machinery.

[0096] Embodiment 2: The present invention provides a three-chamber cylinder four-electrostatic hydraulic actuator system for engineering machinery, which includes a processor, a memory, and a computer program stored in the memory. The computer program can be executed by the processor to implement a control method for a three-chamber cylinder four-electrostatic hydraulic actuator system for engineering machinery as described in any paragraph of Embodiment 1.

[0097] Embodiment 3: The present invention provides a computer-readable storage medium. The computer-readable storage medium includes a stored computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located is controlled to execute a control method for a three-chamber cylinder four-electrostatic hydraulic actuator system of an engineering machinery as described in any paragraph of Embodiment 1.

[0098] In several embodiments provided in the embodiments of the present invention, it should be understood that the disclosed apparatus and method can also be implemented in other ways. The apparatus and method embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the apparatus, method and computer program product according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, program segment or a part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0099] In addition, the functional modules in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0100] If the function is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions to enable a computer device (which can be a personal computer, an electronic device, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program code. It should be noted that in this article, the term "include", "include" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements that are not explicitly listed, or also includes elements inherent to such process, method, article or device. Without more constraints, an element defined by the phrase "comprising a..." does not exclude the existence of other identical elements in the process, method, article or apparatus comprising the element.

[0101] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0102] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0103] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0104] The "first\second" mentioned in the embodiments is only to distinguish similar objects, and does not represent a specific order for the objects. It is understandable that the "first\second" can be interchanged with the specific order or sequence where permitted. It should be understood that the objects distinguished by "first\second" can be interchanged where appropriate, so that the embodiments described herein can be implemented in an order other than those illustrated or described herein.

[0105] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A control method for a three-chamber electrostatic hydraulic actuator system of an engineering machinery, characterized in that: The three-chamber cylinder electrostatic hydraulic actuator system comprises: a three-chamber cylinder (4) provided with an extension chamber (1), a retraction chamber (6) and an energy storage chamber (2), a first locking switch valve (13) connected to the extension chamber (1) by a pipeline, a second locking switch valve (12) connected to the retraction chamber (6) by a pipeline, a bidirectional hydraulic pump / motor (15) having a first oil circuit interface connected to the first locking switch valve (13) and a second oil circuit interface connected to the second locking switch valve (12), a bidirectional electric generator (16) connected to the bidirectional hydraulic pump / motor (15) by transmission, an external accumulator connected to the energy storage chamber (2) by a pipeline, a first overflow valve and a first fixed pressure reducing valve connected to the external accumulator by a pipeline, a first pressure sensor connected to the first oil circuit interface, a second pressure sensor connected to the second oil circuit interface, and a third pressure sensor connected to the external accumulator; The liquid inlet of the first overflow valve is connected to the external accumulator for pressure relief; the liquid outlet of the first fixed value pressure reducing valve is connected to the external accumulator for pressurization; The maximum effective volumes of the extension chamber (1) and the retraction chamber (6) of the three-chamber cylinder (4) are equal; the external accumulator is configured to store energy when the three-chamber cylinder (4) is shortened and release hydraulic energy when the three-chamber cylinder (4) is extended; The control method comprises: A first pressure threshold of the external accumulator is calculated based on the parameters of the engineering machinery and the pressure model of the external accumulator; adjusting the thresholds of the first relief valve and the first fixed-value pressure reducing valve according to the first pressure threshold; Adjust the boom to its initial position; Obtaining a first pressure of the external accumulator, and determining whether the first pressure is lower than a first pressure threshold; When it is determined that the first pressure is lower than the first pressure threshold, the first fixed value pressure reducing valve is pressurized to charge the external accumulator until the first pressure is not less than the first pressure threshold.

2. The control method of a three-chamber electrostatic hydraulic actuator system of an engineering machinery according to claim 1, characterized in that: The pressure model of the external accumulator is: In the formula, The initial external accumulator adjustment pressure is the external accumulator pressure when the boom is lowered to the lowest position. is the total mass of the engineering machinery boom, is the acceleration due to gravity, is the area of ​​the energy storage chamber, It is the regulating pressure of the external accumulator when the three-chamber cylinder is not in the initial position, that is, when the boom is lowered to the lowest position. is the total volume of the external accumulator, is the initial position, i.e. the volume of oil in the external accumulator when the boom is lowered to the lowest position, is the elongation of the three-chamber cylinder compared to the initial position, Charge pressure for external accumulator, is the volume of the external accumulator, For the maximum working pressure, is the gas volume of the external accumulator at the highest pressure, For the minimum working pressure, is the volume of gas in the external accumulator at the lowest pressure, is the polytropic index. When the gas is under isothermal working conditions =1, is a constant.

3. The control method of a three-chamber electrostatic hydraulic actuator system for engineering machinery according to claim 1, characterized in that: The control method further comprises: When the engineering machinery is in a positive load condition, that is, when the load pressure of the engineering machinery boom is raised, the boom is hindered from being raised, or when the load pressure of the engineering machinery boom is hindered from being lowered, the pressure of each chamber of the three-chamber cylinder (4) is obtained, and it is determined that the pressure of the extension chamber (1) and the retraction chamber (6) is less than a second pressure threshold; When it is determined that the pressure of the extension chamber (1) and the retraction chamber (6) is less than a second pressure threshold, a control action is performed according to a control signal, and the pressure of each chamber is monitored in real time; When it is determined that the pressures in the extension chamber (1) and the retraction chamber (6) are not less than a second pressure threshold, driving is stopped until the pressure is reduced to less than the second pressure threshold through the overflow valve.

4. The control method of a three-chamber electrostatic hydraulic actuator system for engineering machinery according to claim 1, characterized in that: The control method further comprises: When the engineering machinery is in a negative load condition, that is, during the lifting process of the engineering machinery boom, the load pressure promotes the lifting of the boom, or during the lowering process of the engineering machinery boom, the load pressure promotes the lowering of the boom: obtaining a first pressure of the external energy storage chamber (2), and determining whether a change rate of the first pressure is greater than a first change rate threshold; When it is determined that the change speed of the first pressure is greater than a first change speed threshold, the bidirectional hydraulic pump / motor (15) switches to a motor mode, and the bidirectional electric generator (16) switches to a generator mode to perform electrical energy recovery.

5. The control method of a three-chamber electrostatic hydraulic actuator system for engineering machinery according to claim 1, characterized in that: The three-chamber cylinder electrostatic hydraulic actuator system also includes: an internal accumulator (8), a second overflow valve (10) for discharging the hydraulic oil of the extension chamber (1) to the internal accumulator (8), a first one-way valve (5) for discharging the hydraulic oil of the internal accumulator (8) to the first oil circuit interface, a third overflow valve (9) for discharging the hydraulic oil of the retraction chamber (6) to the internal accumulator (8), and a second one-way valve (11) for discharging the hydraulic oil of the internal accumulator (8) to the second oil circuit interface.

6. The control method of a three-chamber electrostatic hydraulic actuator system for engineering machinery according to claim 5, characterized in that: The three-chamber cylinder electrostatic hydraulic actuator system further comprises a load-relief switch valve (14) capable of connecting the extension chamber (1) and the retraction chamber (6), and a fourth pressure sensor and an oil replenishment interface connected to the internal accumulator (8); The control method further comprises: Acquiring the pressure of each chamber of the three-chamber cylinder (4), and determining that the pressure of the extension chamber (1) and the retraction chamber (6) is less than a third pressure threshold; When it is determined that the pressures of the extension chamber (1) and the retraction chamber (6) are not less than a third pressure threshold, the unloading switch valve (14) is opened.

7. The control method of a three-chamber electrostatic hydraulic actuator system for engineering machinery according to claim 1, characterized in that: The three-chamber cylinder electrostatic hydraulic actuator comprises a cylinder barrel and an extension rod which is telescopically and movably connected to the cylinder barrel; The cylinder comprises a first tube wall and a second tube wall sleeved on the first tube wall; a first cavity is formed in the first tube wall; A second cavity is formed between the first tube wall and the second tube wall; At least part of the extension rod is constructed as a tubular geometric body and is embedded in the second cavity; the extension cavity (1) is formed between the extension rod and the first cavity; the extension rod is constructed to be able to divide the second cavity into the retraction cavity (6) and the energy storage cavity (2); wherein the change in cavity size of the retraction cavity (6) is opposite to the change in cavity size of the extension cavity (1); and the change in cavity size of the energy storage cavity (2) is the same as the change in cavity size of the extension cavity (1).

8. A three-chamber electrostatic hydraulic actuator system for engineering machinery, characterized in that: It comprises a processor, a memory, and a computer program stored in the memory; the computer program can be executed by the processor to implement a control method for a three-chamber electrostatic hydraulic actuator system of an engineering machinery as described in any one of claims 1 to 7.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute a control method for a three-chamber electrostatic hydraulic actuator system of an engineering machinery as described in any one of claims 1 to 7.

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