Hydraulic excitation offset control method and excitation device

Abstract

The invention relates to the technical field of hydraulic pumps, and provides a hydraulic excitation offset control method, which comprises the following steps that: a controller obtains a feedback signal of a motor encoder of a rotary valve plate to determine a vibration period and a phase, obtains the displacement of a piston in a hydraulic cylinder through a displacement sensor, calculates an actual displacement center value signal, and obtains a deviation value of the actual displacement center value signal and a target displacement center value signal; and the controller outputs a deviation control signal according to the deviation value, the servo valve control current is adjusted, the opening degree of a valve port is changed, and deviation compensation is conducted on displacement and speed of the double-acting hydraulic cylinder. A servo valve is connected in series between an alternating flow distribution pump and a hydraulic cylinder, so that a pump-valve-cylinder cascade offset regulation and control system is constructed. The invention further discloses a vibration excitation device, the displacement center value of the alternating flow distribution pump control vibration excitation hydraulic cylinder can be accurately controlled through the method and device, the servo valve element can be kept in a large opening state in the operation process, and throttling losses are remarkably reduced. The efficient operation of the pump control excitation system is ensured, and the practical application performance of the system is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic pumps, and in particular to a hydraulic excitation offset control method and an excitation device. Background Art

[0002] With the rapid development of modern industry and infrastructure, the performance and reliability of various products and engineering structures under complex working conditions are becoming increasingly important. As core equipment for simulating vibration environments and implementing vibration loading, the importance of vibration excitation systems is becoming increasingly prominent. In the aerospace field, components of spacecraft such as rockets and satellites are subject to the intense vibrations experienced during launch. Using vibration excitation systems to simulate vibration environments for testing effectively ensures their stability and safety under extreme conditions. In construction and water conservancy projects, the seismic performance of reservoirs, dams, and high-rise buildings is crucial to the safety of life and property. Vibration excitation systems can simulate vibration conditions such as earthquakes, providing critical data for the seismic design and assessment of engineering structures. Furthermore, in civil construction, operations such as compaction, drilling, and piling rely on vibration excitation systems to improve efficiency and quality. Currently, electro-hydraulic vibration equipment has become a widely used type of vibration excitation equipment due to its high efficiency and precision. Rotary valve-controlled vibration equipment, with its unique operating principle and performance advantages, plays an irreplaceable role in many engineering scenarios. Its technological development has had a profound impact on improving testing and construction standards in related fields.

[0003] CN 104763604B discloses a hydraulic control pump, a control method for a hydraulic control pump, and an excitation system, comprising: a swash plate, a working surface of which is provided with an annular track coaxially arranged with the swash plate, a head end of a plunger connected to the swash plate is provided with a spherical slider hinged to the plunger; the spherical slider is located in the annular track; a plunger, one end of which extends into the plunger cavity of a cylinder body, and the other end of which can perform circular motion on the working surface of the swash plate around the axis of the swash plate; a cylinder drive shaft, which is rotatably connected to a support seat, is connected to a ball joint at the center of the working surface of the swash plate, and is coaxially and fixedly connected to the cylinder body, and is used to drive the plunger to rotate, so that the plunger performs reciprocating motion in the plunger cavity. The cam is provided with an oil suction / discharge port, and each of the oil suction / discharge ports is provided with a waist-shaped groove corresponding to the cam and arranged on the cylinder body; the waist-shaped grooves form an inner circle waist-shaped groove group and an outer circle waist-shaped groove group; the inner circle waist-shaped groove group and the outer circle waist-shaped groove group are distributed on two circular arcs of different radii on the right end face of the cylinder body and rotate with the cylinder body; the two circular arcs of different radii are respectively provided with an inner distribution channel and an outer distribution channel arranged on the support seat.

[0004] CN 116608184A discloses a hydraulic excitation bias adjustment device, method and hydraulic excitation system, comprising: a servo valve, which is arranged between a double-acting hydraulic cylinder and an alternating flow distribution pump to adjust the flow rate of the alternating fluid flow inputted into the double-acting hydraulic cylinder by the alternating flow distribution pump; a displacement sensor, which is used to detect the actual displacement signal of the double-acting hydraulic cylinder; and a controller, which is electrically connected to the displacement sensor and the servo valve, respectively, and is used to perform the following operations: obtaining the actual displacement signal and deriving the deviation between the target displacement signal and the actual displacement signal; and outputting a deviation control signal according to the deviation to adjust the valve opening of the servo valve and perform offset compensation on the displacement and speed of the double-acting hydraulic cylinder.

[0005] In the existing technology, the alternating flow distribution pump and the pump-controlled hydraulic cylinder have nonlinear factors such as leakage and friction, which lead to asymmetric bidirectional fluid flow and mismatched bidirectional speeds of the pump-controlled hydraulic cylinder, causing the median displacement of the hydraulic cylinder to shift during excitation; if the alternating flow distribution pump has natural asymmetric characteristics, it is impossible to effectively control the hydraulic cylinder offset by adjusting internal components alone; the existing system has problems such as complex control principles and poor control effects, which affects system performance and practicality. Summary of the Invention

[0006] Long-term practice has found that alternating flow distribution pumps and pump-controlled hydraulic cylinders have nonlinear factors such as leakage and friction, which cause bidirectional fluid flow asymmetry and bidirectional speed mismatch of pump-controlled hydraulic cylinders, ultimately causing the median displacement of the hydraulic cylinder to shift during the excitation process. When the alternating flow distribution pump has a natural asymmetric characteristic, it is impossible to effectively control the offset of the hydraulic cylinder by simply adjusting its internal components. For example, by measuring the state variables of the system in real time, such as the displacement, speed, and pressure of the hydraulic cylinder, a model is used to predict the system response at future times, and the optimal control input, such as the valve opening of the servo valve, is calculated based on the prediction results to achieve precise control of the excitation. The calculation process is complex due to the need for precise modeling and real-time complex calculations.

[0007] In view of this, the present invention aims to propose a hydraulic excitation offset control method, including: step S1, the controller obtains the feedback signal of the rotary valve plate motor encoder in the alternating valve pump, and determines the vibration period and phase of the excitation system according to the feedback signal; the controller obtains the piston displacement y in the double-acting hydraulic cylinder through the displacement sensor i , thereby calculating the actual displacement center value signal y of the double-acting hydraulic cylinder center , and get the actual displacement center value signal y center The deviation value a=y from the target displacement center value signal y0 center -y0;

[0008] Step S2: The controller outputs a deviation control signal according to the deviation value a to adjust the control current of the servo valve to adjust the valve opening x of the servo valve. v , offset compensation is performed on the displacement and speed of the double-acting hydraulic cylinder.

[0009] Preferably, in step S2, during the process of the deviation control signal regulating the control current of the servo valve, the actual displacement center value signal y center The deviation value a is calculated from the target displacement center value signal y0. If the deviation value a is positive, the offset direction is positive; if the deviation value a is negative, the offset direction is negative.

[0010] If the offset direction is positive, the controller is used to control the valve opening x of the servo valve in the first stage. v In the second stage, the servo valve port is fully opened;

[0011] If the offset direction is negative, the valve port of the servo valve is fully opened in the first stage, and the valve port opening of the servo valve is controlled by the controller in the second stage. v .

[0012] Preferably, when the controller is used to control the valve opening of the servo valve, the piston movement speed v in the double-acting hydraulic cylinder satisfies v(y center -y0)≥0, then the valve opening X v =f(y center -y o ), where f is the closed-loop control function.

[0013] Preferably, the controller is used to control the valve opening x of the servo valve. v During the process, the phase θ of the rotating distribution plate in the alternating distribution pump satisfies (π-θ)(y center -y0)≥0, then the valve opening X v =f(y center -y0), where f is the closed-loop control function.

[0014] Preferably, the displacement sensor is used to obtain the piston displacement y in the double-acting hydraulic cylinder within one cycle. i , calculate the average value to get y center .

[0015] Preferably, the alternating fluid flow generated by the alternating flow distribution pump serves as the input of the servo valve, and is input into the double-acting hydraulic cylinder after being regulated by the servo valve.

[0016] The present invention also provides an excitation device for the hydraulic excitation offset control method as described above, wherein the excitation device includes the alternating flow distribution pump, the servo valve, the double-acting hydraulic cylinder, the displacement sensor, and the controller. The alternating flow distribution pump can be connected to the servo valve through a pipeline, and the servo valve and the double-acting hydraulic cylinder can be connected to each other through a pipeline. The displacement sensor is used to obtain the displacement of the piston in the double-acting hydraulic cylinder. The displacement sensor is connected to the controller, and the controller is connected to the servo valve.

[0017] Preferably, the P oil port and the T oil port of the servo valve are respectively connected to the two oil outlets of the alternating flow distribution pump, and the two oil outlets of the alternating flow distribution pump can form oil with alternating flow and direction.

[0018] Preferably, the servo valve has a valve opening x v An electro-hydraulic servo valve that is positively correlated with the control current.

[0019] Preferably, the oil port A and the oil port B of the servo valve are respectively connected to the two oil ports of the double-acting hydraulic cylinder.

[0020] The present invention discloses a hydraulic excitation offset control method, in which a controller obtains the feedback signal of the rotating distribution plate motor encoder to determine the vibration period and phase, obtains the piston displacement in the hydraulic cylinder through the displacement sensor, calculates the actual displacement center value signal, and obtains the deviation value between the actual displacement center value signal and the target displacement center value signal; the controller outputs a deviation control signal based on the deviation value, adjusts the servo valve control current, changes the valve opening, and compensates for the displacement and speed of the double-acting hydraulic cylinder. The present invention constructs a pump-valve-cylinder cascade offset control system by connecting a servo valve in series between the alternating distribution pump and the hydraulic cylinder, and proposes a half-cycle segmented correction control strategy based on the distribution plate phase. The present invention also discloses an excitation device, which can accurately control the displacement center value of the alternating distribution pump-controlled excitation hydraulic cylinder. During operation, the servo valve core can maintain a large opening state, significantly reducing throttling losses. It not only ensures the efficient operation of the pump-controlled excitation system, but also greatly improves the actual application performance of the system, effectively balancing system efficiency and practicality.

[0021] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0023] In the attached figure:

[0024] Figure 1Schematic diagram of a hydraulic excitation offset control system according to an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of a positive offset of the center value of a double-acting hydraulic cylinder according to an embodiment of the present invention;

[0026] Figure 3 A schematic diagram of a negative offset of the center value of a double-acting hydraulic cylinder according to an embodiment of the present invention;

[0027] Figure 4 Schematic diagram of a hydraulic excitation offset control method according to an embodiment of the present invention;

[0028] Figure 5 A displacement curve diagram of a double-acting hydraulic cylinder directly controlled by an alternating flow distribution pump and controlled by a hydraulic excitation offset control method according to an embodiment of the present invention;

[0029] Figure 6 A curve diagram showing the percentage of valve core displacement of a servo valve in a hydraulic excitation offset control method according to an embodiment of the present invention;

[0030] Figure 7 This is a schematic diagram of the working principle of an alternating flow distribution pump according to an embodiment of the present invention.

[0031] Description of reference numerals:

[0032] 1. Alternating flow distribution pump; 2. Servo valve; 3. Double-acting hydraulic cylinder; 4. Displacement sensor; 5. Controller. DETAILED DESCRIPTION

[0033] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0034] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first," "second," "third," etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate to facilitate the embodiments of the present invention described herein. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatuses.

[0036] In order to solve the problem in the prior art that the alternating flow distribution pump and the pump-controlled hydraulic cylinder have nonlinear factors such as leakage and friction, which cause asymmetric bidirectional fluid flow and mismatch of bidirectional speed of the pump-controlled hydraulic cylinder, and finally cause the median displacement of the hydraulic cylinder to shift during the excitation process. When the alternating flow distribution pump has a natural asymmetric characteristic, it is impossible to effectively control the offset of the hydraulic cylinder by adjusting its internal components. For example, by measuring the state variables of the system in real time, such as the displacement, speed and pressure of the hydraulic cylinder, the model is used to predict the system response at future times, and the optimal control input, such as the valve opening of the servo valve, is calculated based on the prediction results to achieve precise control of the excitation. Due to the need for precise modeling and real-time complex calculations, the calculation process is complicated and other technical problems. The present invention provides a hydraulic excitation offset control method, such as Figure 1-7 As shown, a schematic diagram of a hydraulic excitation offset control method according to an embodiment of the present invention is provided. The hydraulic excitation offset control method includes:

[0037] Step S1: The controller 5 obtains the feedback signal of the rotary valve plate motor encoder in the alternating valve pump 1, and determines the vibration period and phase of the excitation system according to the feedback signal; the controller 5 obtains the piston displacement y in the double-acting hydraulic cylinder 3 through the displacement sensor 4. i , thereby calculating the actual displacement center value signal y of the double-acting hydraulic cylinder 3 center , and get the actual displacement center value signal y center The deviation value a=y from the target displacement center value signal y0 center -y0;

[0038] Step S2: the controller 5 outputs a deviation control signal according to the deviation value a, and adjusts the control current of the servo valve 2 to adjust the valve opening x of the servo valve 2. v , the displacement and speed of the double-acting hydraulic cylinder 3 are offset compensated.

[0039] The present invention discloses a hydraulic excitation offset control method, in which the controller obtains the feedback signal of the rotating distribution plate motor encoder to determine the vibration period and phase, obtains the piston displacement in the hydraulic cylinder through the displacement sensor, calculates the actual displacement center value signal, and obtains the deviation value between the actual displacement center value signal and the target displacement center value signal; the controller outputs a deviation control signal based on the deviation value, adjusts the servo valve control current, changes the valve opening, and performs offset compensation on the displacement and speed of the double-acting hydraulic cylinder. The present invention constructs a pump-valve-cylinder cascade offset control system by connecting a servo valve in series between the alternating distribution pump and the hydraulic cylinder, and proposes a half-cycle segmented correction control strategy based on the distribution plate phase. This method can accurately control the displacement center value of the alternating distribution pump-controlled excitation hydraulic cylinder, and the servo valve core can maintain a large opening state during operation, significantly reducing throttling losses. It not only ensures the efficient operation of the pump-controlled excitation system, but also greatly improves the actual application performance of the system, effectively balancing system efficiency and practicality.

[0040] The controller 5 is used to obtain the feedback of the rotating distribution plate motor encoder to obtain the vibration period and phase of the excitation system; obtain the actual displacement signal of the piston in the hydraulic cylinder, and calculate the deviation value between the actual displacement center value signal and the target displacement center value signal; output the deviation control signal according to the deviation value to adjust the valve opening of the servo valve 2 and perform offset compensation on the displacement and speed of the double-acting hydraulic cylinder 3. In order to accurately identify the specific direction in which the displacement center of the double-acting hydraulic cylinder deviates from the target position, a clear direction guide is provided for the subsequent deviation correction control, so that the system's perception of the deviation situation is more accurate and sensitive. In a more preferred case of the present invention, in step S2, during the process of the deviation control signal adjusting the control current of the servo valve 2, the actual displacement center value signal yce nte The deviation value a is calculated from r and the target displacement center value signal y0. If the deviation value a is positive, the offset direction is positive; if the deviation value a is negative, the offset direction is negative.

[0041] If the offset direction is positive, the controller 5 is used to control the valve opening x of the servo valve 2 in the first stage. v In the second stage, the servo valve 2 is fully opened;

[0042] If the offset direction is negative, the valve port of the servo valve 2 is fully opened in the first stage, and the valve port opening x of the servo valve 2 is controlled by the controller 5 in the second stage. vAfter the offset direction is determined, the control current of the servo valve is adjusted based on the deviation control signal, thereby adjusting the valve opening of the servo valve. Targeted compensation control can be performed for different offset directions. This method adapts to the displacement offset that may occur in the hydraulic cylinder under different working conditions. Regardless of load changes, system parameter fluctuations, or other interference factors, the deviation value can be calculated in real time and the offset direction can be determined, allowing the servo valve to be adjusted in a timely manner. This ensures that the system can effectively control the displacement center value of the hydraulic cylinder under various complex conditions, enhancing the system's adaptability to different working environments and working conditions.

[0043] like Figure 1 As shown, during the excitation process, the alternating flow distribution pump 1 itself can only roughly control the excitation amplitude. For this reason, the hydraulic excitation offset control method adopted by the present invention sets a servo valve 2 between the alternating flow distribution pump 1 and the double-acting hydraulic cylinder 3. The servo valve 2 is preferably an electro-hydraulic servo valve, and the opening of its valve port is positively correlated with the control current of the servo valve 2. By adjusting the control current of the servo valve 2, the bidirectional fluid flow to the double-acting hydraulic cylinder 3, that is, the fluid flow of the A oil port and the B oil port, can be changed. The dynamic response of the servo valve 2 is fast and the control accuracy is high. Therefore, the actual displacement center value signal yce is transmitted through the controller 5. nte Compare r with the target displacement center value signal y0 to obtain the actual displacement center value signal yce nte The deviation between r and the target displacement center value signal y0 is calculated. The deviation control signal is then used to control the control current of the servo valve 2, thereby adjusting the valve opening of the servo valve 2. This causes the bidirectional flow of the alternating flow distribution pump 1 input to the double-acting hydraulic cylinder 3 through the servo valve 2 to decrease synchronously, thus achieving offset compensation for the displacement and speed of the double-acting hydraulic cylinder 3. The servo valve 2 is used to precisely control the excitation amplitude, ensuring that the displacement of the double-acting hydraulic cylinder 3 meets the set target and does not deviate. In addition, see Figure 1 The servo valve 2 is a three-position, four-way electromagnetic reversing valve. Since the alternating flow distribution pump 1 itself can generate alternating fluid flow, the servo valve 2 only needs to be adjusted at a larger opening in one direction when controlling the alternating fluid flow. The valve core of the servo valve 2 does not need to alternate between positive and negative movements near the zero position like a pure valve-controlled excitation system, that is, the servo valve 2 will not switch back and forth between the upper and lower positions, avoiding the servo valve 2 opening being too small during the switching process, resulting in excessive throttling losses. Since the servo valve 2 only needs to adjust the valve opening in one direction, the servo valve 2 can also use a two-position, four-way electromagnetic reversing valve. The servo valve 2 is diverse, as long as it has the function of adjusting the valve opening in one direction.

[0044] Figure 2 、 Figure 3The time-displacement motion characteristics of the double-acting hydraulic cylinder 3 controlled by the alternating flow pump 1 are shown in Figure 1. The dashed line represents the ideal displacement curve of the alternating flow pump 1, while the solid line represents the actual displacement curve of the hydraulic cylinder directly controlled by the alternating flow pump 1. The target displacement curve is the ideal displacement curve. If there is a deviation between the actual displacement curve and the target displacement curve at the same time, it is necessary to control the valve opening of the servo valve 2 to control the bidirectional flow to the double-acting hydraulic cylinder 3, thereby adjusting the displacement speed of the double-acting hydraulic cylinder 3. The displacement of the double-acting hydraulic cylinder 3 has positive and negative values, see [1]. Figure 2 , according to the positive and negative changes in the displacement direction, the target displacement curve is divided into the first stage and the second stage from left to right. When the vibration center value of the hydraulic cylinder shifts in the positive direction, such as Figure 2 As shown. In the first stage, the valve opening of the servo valve 2 needs to be controlled to become smaller to reduce the displacement variation of the double-acting hydraulic cylinder 3. The servo valve opening should be appropriately reduced to reduce the offset speed. In the second stage, the servo valve should be fully opened to increase the displacement variation of the double-acting hydraulic cylinder 3 and reduce the throttling loss. Correspondingly, when the vibration center value of the hydraulic cylinder shifts to the negative direction, as shown in Figure 3 As shown. In the first stage, the servo valve port should be fully opened to increase the displacement change amplitude of the double-acting hydraulic cylinder 3 and reduce throttling losses. In the second stage, it is necessary to control the valve port opening of the servo valve 2 to become smaller to reduce the displacement change amplitude of the double-acting hydraulic cylinder 3. The valve port opening of the servo valve 2 should be appropriately reduced to reduce the offset speed. Different control methods are used according to different offset directions to compensate for the deviation between the target displacement center value and the actual displacement center value, so that the actual displacement center value can match the target displacement center value. That is, different deviation control signals are output according to different offset directions, as follows:

[0045] The hydraulic cylinder offset direction is determined based on the actual displacement center value signal. If the actual displacement center value is greater than or equal to the target displacement center value, the deviation value is used as the deviation control signal. If the actual displacement center value is less than the target displacement center value, the deviation value is used as the deviation control signal. The control current of the servo valve 2 is adjusted based on the deviation control signal to adjust the valve opening of the servo valve 2 and compensate for the displacement and speed of the double-acting hydraulic cylinder 3.

[0046] The controller 5 includes a closed-loop controller, which converts the deviation control signal into a control quantity through linear combination according to proportion, integration and differentiation, and adjusts the proportional, integral and differential parameters in real time through fuzzy logic, thereby adjusting the control current of the servo valve 2 according to the control quantity to adjust the valve opening of the servo valve 2. For example, the closed-loop control algorithm can combine the reliability of traditional PID (proportional-integral-differential) control and the intelligent advantages of fuzzy control, and improve the adaptability to nonlinearity, uncertainty and disturbance by dynamically adjusting parameters, and show higher reliability under complex working conditions. In a more preferred embodiment of the present invention, when the controller 5 is used to control the valve opening of the servo valve 2, the piston movement speed v in the double-acting hydraulic cylinder 3 satisfies v(y center -y0)≥0, then the valve opening X v =f(y center -y0), where f is a closed-loop control function. The closed-loop control function f includes a closed-loop control algorithm function, such as the fuzzy PID algorithm. That is, fuzzy control does not rely on a precise mathematical model of the controlled object. It can use fuzzy rules to make inferences and decisions based on information such as the system error and error change rate, thereby flexibly controlling the system.

[0047] As a specific embodiment of the hydraulic excitation offset control method of the present invention, see Figure 4 The flow rate of the alternating fluid output by the alternating flow pump 1 is controlled by the rotating flow plate speed Ω, the cylinder speed ω and the swash plate angle β, and the flow rate q and pressure P of the alternating fluid output by the alternating flow pump 1 are adjusted by the servo valve 2 to be the flow rate q c and pressure P c Input double-acting hydraulic cylinder 3 to control the valve opening x of servo valve 2 v So as to be able to adjust the size of the two-way flow to the double-acting hydraulic cylinder 3. During the excitation process, the actual displacement of the double-acting hydraulic cylinder 3 is monitored by the displacement sensor 4 to form an actual displacement curve. If the actual displacement center value is greater than or equal to the target displacement center value, the deviation value between the actual displacement center value and the target displacement center value is directly used as the deviation control signal. If the actual displacement center value is less than the target displacement center value, the deviation value is inverted as the deviation control signal. The segmented closed-loop controller converts the deviation control signal into a control quantity through a linear combination of proportion, integration and differentiation, and thus adjusts the control current of the servo valve 2 according to the control quantity, so as to be able to adjust the valve opening of the servo valve 2, and adopts different segmented control schemes according to the offset direction of the actual displacement center value to achieve offset compensation of the displacement and speed of the double-acting hydraulic cylinder 3.

[0048] The hydraulic cylinder displacement signal collected by the displacement sensor 4 will be disturbed, and using this signal to calculate the hydraulic cylinder speed will cause the speed direction to be distorted. Considering that for an alternating flow pump, the piston speed is determined by the flow rate. In a more preferred embodiment of the present invention, the controller 5 is used to control the valve opening x of the servo valve 2. v During the process, the phase θ of the rotating distribution plate in the alternating distribution pump 1 satisfies (π-θ)(y center -y0)≥0, then the valve opening x v =f(y center -y0), where f is the closed-loop control function.

[0049] In order to dynamically monitor the displacement center value of the hydraulic cylinder and timely reflect the displacement change trend of the hydraulic cylinder during operation, whether the system is in steady state operation or is subject to external disturbances, it can be based on the real-time updated y center The value provides accurate feedback to the control link, so that the control system can quickly sense the offset and respond. In a more preferred embodiment of the present invention, the displacement sensor 4 is used to obtain the piston displacement y in the double-acting hydraulic cylinder 3 within one cycle. i , calculate the average value to get y center Comprehensively consider the displacement changes throughout the entire cycle, effectively eliminate the influence of transient interference and local fluctuations, and accurately characterize the center position of the double-acting hydraulic cylinder piston displacement.

[0050] In order to be able to quickly respond and adjust the liquid flow input to the hydraulic cylinder according to the actual operating conditions. Whether the hydraulic cylinder needs to start or stop quickly, or maintain stable operation under different loads, the servo valve can adjust the liquid flow in time, enhance the system's adaptability to complex working conditions and the flexibility of control, and effectively avoid abnormal operation of the hydraulic cylinder due to flow mismatch. In a more preferred embodiment of the present invention, the alternating liquid flow generated by the alternating flow distribution pump 1 is used as the input of the servo valve 2, and is input into the double-acting hydraulic cylinder 3 after adjustment by the servo valve 2. The servo valve's regulation of the liquid flow is used to compensate for the offset of the displacement and speed of the double-acting hydraulic cylinder 3. When it is detected that the actual displacement center value is offset, the servo valve 2 is adjusted to control the liquid flow, which can change the motion state of the double-acting hydraulic cylinder 3 and return it to the target position, thereby achieving effective control of the offset of the double-acting hydraulic cylinder 3 and improving the control accuracy and performance of the system.

[0051] The present invention also provides an excitation device for the above-mentioned hydraulic excitation offset control method, wherein the excitation device includes the alternating flow distribution pump 1, the servo valve 2, the double-acting hydraulic cylinder 3, the displacement sensor 4, and the controller 5. The alternating flow distribution pump 1 can be connected to the servo valve 2 through a pipeline, and the servo valve 2 and the double-acting hydraulic cylinder 3 can be connected through a pipeline. The displacement sensor 4 is used to obtain the piston displacement in the double-acting hydraulic cylinder 3. The displacement sensor 4 is connected to the controller 5, and the controller 5 is connected to the servo valve 2.

[0052] The present invention discloses an excitation device for the above-mentioned hydraulic excitation offset control method, which integrates an alternating flow distribution pump 1, a servo valve 2, a double-acting hydraulic cylinder 3, a displacement sensor 4 and a controller 5. Among them, the alternating flow distribution pump 1 and the servo valve 2, and the servo valve 2 and the double-acting hydraulic cylinder 3 are respectively connected in series through pipelines to construct a complete hydraulic transmission path. The displacement sensor 4 collects the piston displacement data in the double-acting hydraulic cylinder 3 in real time and transmits the signal to the controller 5. The controller 5 generates a control instruction based on the received displacement information, establishes an electrical connection with the servo valve 2, and realizes precise control of the valve opening. The device can accurately control the displacement center value of the alternating flow distribution pump-controlled excitation hydraulic cylinder. During operation, the servo valve core can maintain a relatively large opening state, significantly reducing throttling losses. It not only ensures the efficient operation of the pump-controlled excitation system, but also greatly improves the actual application performance of the system, effectively balancing the system efficiency and practicality.

[0053] like Figure 7As shown, the alternating flow pump 1 is a hydraulic control pump capable of outputting alternating fluid flow and controlling the frequency and output flow of the alternating fluid flow, thereby controlling the reciprocating frequency and excitation amplitude of the double-acting hydraulic cylinder 3. The alternating flow pump 1 has various structural forms. As a specific structural form of the alternating flow pump 1, it mainly includes a fixed valve plate, a rotating valve plate, a plunger cylinder, and a swash plate. The rear end surface of the rotating valve plate contacts the front end surface of the fixed valve plate, and the front end surface of the rotating valve plate contacts the plunger cylinder. The plunger cylinder has multiple circular holes distributed along the circumference, each of which has a plunger inserted into it. The multiple plungers are capable of moving axially along the plunger cylinder. A swash plate is disposed at the front ends of the multiple plungers, and the rotation axis of the swash plate forms an angle with the axis of the plunger cylinder. During operation, the plungers are pressed against the working surface of the swash plate by the hydraulic oil in the plunger cylinder, resulting in different lengths of each plunger extending from the end surface of the plunger cylinder. The working section of the fixed distribution disc forms two inner and outer annular grooves of different diameters. The two annular grooves extend axially inward. The inner annular groove is connected to one working chamber interface of the double-acting hydraulic cylinder 3, and the outer annular groove is connected to the other working chamber interface of the double-acting hydraulic cylinder 3. Two inner distribution channels I and outer distribution channels II with arc-shaped cross-sections are provided on the rotating distribution disc. When the alternating distribution pump 1 is working, by continuously rotating the plunger cylinder body, under the action of the inclined plate, the plunger is made to reciprocate in the plunger cylinder body, forming a phase-fixed oil suction area and oil discharge area. By driving the rotating distribution disc to rotate, the rotating distribution disc is rotated relative to the fixed distribution disc, and the rotating distribution disc is rotated relative to the plunger cylinder body, so that the contact area between the two distribution channels I and II of the rotating distribution disc and the oil suction area and oil discharge area of the plunger cylinder body changes. As shown Figure 7 As shown, the zero point of the rotation angle of the two distribution channels I and II of the rotating distribution plate is defined, that is, The contact area between the rotating valve plate's inner flow channel I and the plunger cylinder's oil suction and discharge areas is identical, while the contact area between the rotating valve plate's outer flow channel II and the plunger cylinder's oil suction and discharge areas is identical. This means the input flow rate through the fixed valve plate's inner annular groove B and the output flow rate through the outer annular groove A are both zero. As the rotating valve plate rotates, the input and output flows of the alternating flow pump change.

[0054] : As the contact area between the inner distribution channel I of the rotating distribution plate and the oil suction area of the plunger cylinder body and the contact area between the outer distribution channel II of the rotating distribution plate and the oil discharge area of the plunger cylinder body gradually increase, the input flow of the inner annular groove B of the fixed distribution plate and the output flow of the outer annular groove A increase at the same time.

[0055] : The input flow of the inner annular groove B of the fixed distribution plate and the output flow of the outer annular groove A reach the maximum.

[0056] : The contact area between the inner distribution channel I of the rotating distribution plate and the oil suction area of the plunger cylinder body, as well as the contact area between the outer distribution channel II of the rotating distribution plate and the oil discharge area of the plunger cylinder body gradually decreases, and the input flow of the inner annular groove B of the fixed distribution plate and the output flow of the outer annular groove A simultaneously decrease.

[0057] : The input flow of the inner annular groove B of the fixed distribution plate and the output flow of the outer annular groove A are reduced to zero.

[0058] : As the contact area between the external distribution channel II of the rotating distribution plate and the oil suction area of the plunger cylinder body and the contact area between the internal distribution channel I of the rotating distribution plate and the oil discharge area of the plunger cylinder body gradually increase, the input flow of the outer annular groove A of the fixed distribution plate and the output flow of the inner annular groove B increase at the same time.

[0059] : The input flow of the outer annular groove A of the fixed distribution plate and the output flow of the inner annular groove B reach the maximum.

[0060] : The contact area between the external distribution channel II of the rotating distribution plate and the oil suction area of the plunger cylinder body, as well as the contact area between the internal distribution channel I of the rotating distribution plate and the oil discharge area of the plunger cylinder body gradually decreases, and the input flow of the outer annular groove A of the fixed distribution plate and the output flow of the inner annular groove B simultaneously decrease.

[0061] : The input flow of the outer annular groove A of the fixed distribution plate 5 and the output flow of the inner annular groove B are reduced to zero.

[0062] This cycle creates an alternating flow and direction of oil flowing through the two ports of the alternating flow pump 1, driving the double-acting hydraulic cylinder 3 to reciprocate. By varying the rotational speed of the rotating valve plate, the reciprocating frequency of the double-acting hydraulic cylinder 3 varies accordingly. By varying the cylinder speed (i.e., the plunger speed), the output flow of the plunger pump changes, thereby varying the excitation amplitude of the double-acting hydraulic cylinder 3. By changing the swash plate angle, the displacement of the plunger pump can also be varied, thereby varying the excitation amplitude of the double-acting hydraulic cylinder 3.

[0063] The P oil port and T oil port of the servo valve 2 are respectively connected to the two oil outlets of the alternating flow distribution pump, which can fully utilize the oil with alternating flow and direction generated by the alternating flow distribution pump 1 to provide alternating hydraulic power for the double-acting hydraulic cylinder 3. This connection method allows the double-acting hydraulic cylinder to achieve reciprocating motion under the action of the alternating fluid flow, meets the requirements of the excitation device for the motion form of the hydraulic cylinder, and provides basic conditions for achieving hydraulic excitation. In a more preferred embodiment of the present invention, the P oil port and T oil port of the servo valve 2 are respectively connected to the two oil outlets of the alternating flow distribution pump 1, and the two oil outlets of the alternating flow distribution pump 1 can form oil with alternating flow and direction.

[0064] This makes the electrical signal output by the controller form a linear mapping relationship with the hydraulic flow control. This linear correspondence facilitates precise control of the valve opening by accurately adjusting the control current, thereby stably controlling the oil flow input to the double-acting hydraulic cylinder, and ensuring precise control of parameters such as the hydraulic cylinder displacement and speed. In a more preferred embodiment of the present invention, the servo valve 2 is a valve opening x v An electro-hydraulic servo valve that is positively correlated with the control current. By precisely adjusting the valve opening with controlled current, the oil flow can be distributed on demand, avoiding the energy waste caused by traditional throttling and improving system energy efficiency.

[0065] The A and B ports of the servo valve are respectively connected to the two ports of the double-acting hydraulic cylinder, which can realize bidirectional drive of the hydraulic cylinder. By controlling the oil flow and pressure of the A and B ports, the extension and contraction action of the hydraulic cylinder can be accurately adjusted to meet the precise control requirements of the reciprocating motion of the piston in the hydraulic excitation system, and ensure the accuracy and stability of the excitation displacement, speed and other parameters. In a more preferred embodiment of the present invention, the A and B ports of the servo valve 2 are respectively connected to the two ports of the double-acting hydraulic cylinder 3. This enables the system to flexibly change the movement direction, speed and acceleration of the hydraulic cylinder. Under different excitation working conditions, the inlet and outlet oil states and flow rates of the A and B ports can be adjusted by the servo valve according to actual needs to achieve rapid start-up, smooth operation or precise stopping of the hydraulic cylinder, effectively improving the adaptability of the excitation device to complex working conditions. Combined with the piston displacement information of the double-acting hydraulic cylinder 3 fed back by the displacement sensor 4, the controller 5 can adjust the oil of the A and B ports in real time through the servo valve 2 according to the deviation. Whether compensating for the displacement center offset of the double-acting hydraulic cylinder 3 or correcting the speed difference, the oil in the A and B oil ports can be precisely controlled to achieve closed-loop control of the motion state of the double-acting hydraulic cylinder 3, ensuring the accuracy and reliability of the operation of the vibration device.

[0066] In order to better reflect the displacement compensation effect of the hydraulic excitation offset control method of the present invention on the double-acting hydraulic cylinder 3 during the excitation process. Figure 5As shown in the figure, "no control y" represents the displacement curve of the hydraulic cylinder directly controlled by the alternating flow distribution pump 1, and "control y" represents the displacement curve of the hydraulic cylinder controlled by the hydraulic excitation offset control method of the present invention. It can be clearly seen that under the control of the hydraulic excitation offset control method of the present invention, the displacement curve of the hydraulic cylinder is more symmetrical than that directly controlled by the alternating flow distribution pump 1. Figure 5 The changing trends of the actual displacement center value of the hydraulic cylinder over time under the two control modes shown, compared with the direct control of the alternating flow distribution pump 1, the displacement center value of the hydraulic cylinder under the control of the center offset control method of the alternating flow distribution pump-controlled hydraulic excitation system of the present invention quickly reaches stability, so that the displacement of the hydraulic cylinder meets the set target, and can effectively suppress the drift phenomenon, that is, avoid the displacement of the hydraulic cylinder from being offset. At the same time, during the hydraulic excitation process, the hydraulic excitation offset control method of the present invention is to control the valve core movement of the servo valve 2 to perform offset adjustment. According to the throttle valve principle, the smaller the valve opening, the more obvious the throttling effect and the greater the throttling loss. During the offset compensation process, the servo valve 2 of the hydraulic excitation offset control method of the present invention has its valve core basically in a large unidirectional opening, and the alternating fluid flow is generated by the alternating flow distribution pump 1. Therefore, as Figure 6 As shown, the percentage of the valve core displacement of the servo valve 2 of the hydraulic excitation offset control method of the present invention to the full stroke is basically all above 50%. During the offset adjustment process, the throttling loss of the hydraulic excitation offset control method of the present invention is small.

[0067] It should be noted that for the aforementioned method embodiments, for simplicity of description, they are all expressed as a series of action combinations. However, those skilled in the art should be aware that the present invention is not limited by the order of the actions described, because according to the present invention, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in this specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0068] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0069] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0070] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A hydraulic excitation offset control method, characterized in that: The hydraulic excitation offset control method includes: Step S1: The controller (5) obtains the feedback signal of the rotary valve plate motor encoder in the alternating valve pump (1), and determines the vibration period and phase of the excitation system according to the feedback signal; the controller (5) obtains the piston displacement y in the double-acting hydraulic cylinder (3) through the displacement sensor (4). i , thereby calculating the actual displacement center value signal y of the double-acting hydraulic cylinder (3) center , and get the actual displacement center value signal y center The deviation value a=y from the target displacement center value signal y0 center -y0; Step S2, the controller (5) outputs a deviation control signal according to the deviation value a, and adjusts the control current of the servo valve (2) to adjust the valve opening x of the servo valve (2). v , offset compensation is performed on the displacement and speed of the double-acting hydraulic cylinder (3).

2. The hydraulic excitation offset control method according to claim 1, characterized in that: In step S2, during the process of adjusting the control current of the servo valve (2) by the deviation control signal, the actual displacement center value signal y center The deviation value a is calculated from the target displacement center value signal y0. If the deviation value a is positive, the offset direction is positive; if the deviation value a is negative, the offset direction is negative. If the offset direction is the positive direction, the controller (5) is used in the first stage to control the valve opening x of the servo valve (2). v In the second stage, the servo valve (2) is fully opened; If the offset direction is negative, the valve port of the servo valve (2) is fully opened in the first stage, and the valve port opening of the servo valve (2) is controlled by the controller (5) in the second stage. v .

3. The hydraulic excitation offset control method according to claim 2, characterized in that: When the controller (5) is used to control the valve opening of the servo valve (2), the piston movement speed v in the double-acting hydraulic cylinder (3) satisfies v(y center -y0)≥0, then the valve opening X v =f(y center -y0), where f is the closed-loop control function.

4. The hydraulic excitation offset control method according to claim 2, characterized in that: The controller (5) is used to control the valve opening x of the servo valve (2). v During the process, the phase θ of the rotating distribution plate in the alternating distribution pump (1) satisfies (π-θ)(y center -y0)≥0, then the valve opening X v =f(y center -y0), where f is the closed-loop control function.

5. The hydraulic excitation offset control method according to claim 1, characterized in that: The displacement amount y of the piston in the double-acting hydraulic cylinder (3) within one cycle is obtained by the displacement sensor (4). i , calculate the average value to get y center .

6. The hydraulic excitation offset control method according to any one of claims 1 to 5, characterized in that: The alternating fluid flow generated by the alternating flow distribution pump (1) serves as the input of the servo valve (2), and is input into the double-acting hydraulic cylinder (3) after being regulated by the servo valve (2).

7. A vibration excitation device for use in the hydraulic excitation offset control method according to any one of claims 1 to 6, characterized in that: The excitation device comprises the alternating flow distribution pump (1), the servo valve (2), the double-acting hydraulic cylinder (3), the displacement sensor (4), and the controller (5). The alternating flow distribution pump (1) can be connected to the servo valve (2) through a pipeline, the servo valve (2) and the double-acting hydraulic cylinder (3) can be connected through a pipeline, the displacement sensor (4) is used to obtain the displacement of the piston in the double-acting hydraulic cylinder (3), the displacement sensor (4) is connected to the controller (5), and the controller (5) is connected to the servo valve (2).

8. The vibration excitation device according to claim 7, characterized in that: The P oil port and the T oil port of the servo valve (2) are respectively connected to the two oil outlets of the alternating flow distribution pump (1), and the two oil outlets of the alternating flow distribution pump (1) can form oil with alternating flow and direction.

9. The vibration excitation device according to claim 7, characterized in that: The servo valve (2) is a valve opening x v An electro-hydraulic servo valve that is positively correlated with the control current.

10. The vibration excitation device according to any one of claims 7 to 9, characterized in that: The oil port A and the oil port B of the servo valve (2) are respectively connected to the two oil ports of the double-acting hydraulic cylinder (3).

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