Hydraulic system, hydraulic system anti-interference control method and construction equipment

Abstract

The application discloses a hydraulic system, a hydraulic system anti-interference control method and construction equipment, and relates to the technical field of hydraulic systems. The hydraulic system comprises a power source, a variable pump, a multi-way valve, an execution power mechanism, a controller, a load-sensitive feedback oil circuit and a pressure dynamic correction mechanism; the execution power mechanism is connected with the output end of the multi-way valve, and the pressure dynamic correction mechanism is connected to the load-sensitive feedback oil circuit; the pressure dynamic correction mechanism comprises at least two throttle branches that are respectively connected with different pressure nodes, and the at least two throttle branches automatically distribute hydraulic oil flow according to the pressure difference formed at both ends. The application can realize real-time dynamic correction of feedback pressure without additional electrically-controlled execution elements. When the load suddenly changes, the pressure dynamic correction mechanism can quickly adjust the load-sensitive feedback pressure, so that the variable pump can timely correct the output pressure and flow, and effectively reduce the overshoot of the feedback pressure, pressure lag and flow fluctuation.

Description

Technical Field

[0001] This invention relates to the field of hydraulic system technology, and more specifically, to a hydraulic system. Furthermore, this invention also relates to a hydraulic system anti-interference control method applied to the aforementioned hydraulic system, and a construction device including the aforementioned hydraulic system. Background Technology

[0002] Hydraulic systems, due to their advantages such as high output power and fast response speed, are widely used in engineering machinery, mining machinery, and mobile crushing and screening equipment. They typically serve as the power source for actuators, driving the conveying mechanism through variable displacement pumps, multi-way valves, and hydraulic motors. Because the weight of the material carried by the conveying mechanism constantly changes, the load on the hydraulic system exhibits abrupt and random characteristics, placing high demands on the system's dynamic response speed, control accuracy, and anti-interference capabilities.

[0003] Currently, load-sensitive hydraulic systems adjust the displacement of variable pumps through load-sensitive feedback circuits. However, when the load suddenly increases or decreases, the feedback pressure is prone to problems such as lag, overshoot, and pressure pulsation, causing the variable pump displacement to be adjusted untimely. This leads to actuator speed fluctuations, system pressure shocks, and decreased operational stability. Furthermore, existing control methods mostly employ PID control or constant current control, which have limited adaptability to load disturbances and system parameter changes, making it difficult to balance control accuracy, response speed, and system stability.

[0004] In summary, how to provide a hydraulic system that avoids lag in feedback pressure regulation, insufficient anti-interference capability, low control accuracy, and poor system stability under sudden load changes is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a hydraulic system that can avoid the problems of delayed feedback pressure regulation, insufficient anti-interference ability, low control accuracy and poor system stability under sudden load conditions.

[0006] Another objective of this invention is to provide a hydraulic system anti-interference control method applied to the aforementioned hydraulic system, and a construction device including the aforementioned hydraulic system.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A hydraulic system, comprising: Power source; A variable displacement pump is connected to the power source; A multi-way valve is connected to the output end of the variable pump; An actuator is connected to the output end of the multi-way valve, and the actuator is used to drive the transmission mechanism to operate. A controller is used to control the operation of the multi-way valve according to the operating state of the actuator; A load-sensitive feedback oil circuit is connected between the multi-way valve and the variable pump; A pressure dynamic correction mechanism is connected to the load-sensitive feedback oil circuit. The pressure dynamic correction mechanism includes at least two throttling branches that are respectively connected to different pressure nodes. The at least two throttling branches automatically distribute the hydraulic oil flow based on the pressure difference formed at both ends, so as to change the feedback pressure in the load-sensitive feedback oil circuit and dynamically correct the pressure compensation signal of the variable pump.

[0008] Optionally, the pressure dynamic correction mechanism includes a first throttling branch and a second throttling branch. One end of the first throttling branch is connected to the load-sensitive feedback oil circuit, and the other end is connected to the oil tank. One end of the second throttling branch is connected to the variable pump, and the other end is connected to the load-sensitive feedback oil circuit. The first throttling branch and the second throttling branch form a bridge-type hydraulic resistance network, which is used to automatically adjust the hydraulic oil flow rate in each throttling branch according to the pressure difference formed between different pressure nodes.

[0009] Optionally, the bridge-type hydraulic resistance network is a C-type half-bridge, which includes a first throttle valve and a second throttle valve. The first throttle valve and the second throttle valve are respectively connected to different pressure nodes. When the pressure between each pressure node changes, the hydraulic oil automatically selects the flow path according to the pressure difference formed at both ends of each throttle valve, so as to dynamically correct the feedback pressure of the load-sensitive feedback oil circuit.

[0010] Optionally, the first throttle valve is an adjustable flow valve; When the load on the transmission mechanism decreases, the feedback pressure in the load-sensitive feedback oil circuit increases, and the pressure difference between the two ends of the first throttling branch increases; the hydraulic oil preferentially flows to the oil tank through the first throttling branch to reduce the feedback pressure. When the load on the transmission mechanism increases, the pressure difference between the two ends of the first throttling branch decreases, and the bridge-type liquid resistance network re-establishes pressure balance, thereby increasing the output pressure and flow rate of the variable pump.

[0011] A hydraulic system anti-interference control method, applied to any of the hydraulic systems described above, the hydraulic system anti-interference control method comprising: Obtain the actual speed v of the actuator and the target speed v of the transmission mechanism. ref ; Based on the actual speed v and the target speed v ref Calculate the speed error e, and based on the speed error e and the rate of change of the speed error... Establish the sliding surface s; Establish a control algorithm model, and calculate the control current u of the multi-way valve based on the control algorithm model; The control current u controls the multi-way valve to regulate the pressure and flow rate of the hydraulic oil output to the actuator. The system determines whether the target operating state has been reached based on the actual operating state of the actuator. If the target operating state has not been reached, the control current u is recalculated and the multi-way valve is adjusted. If the target operating state has been reached, the current control current u is maintained, and the actual operating state of the actuator is periodically detected to form a closed-loop control.

[0012] Optionally, the step of basing the actual speed v and the target speed v ref The speed error e is calculated, including: Calculate the speed error e using the following formula. ; The speed error e and the rate of change of speed error are based on the speed error e. Establish the sliding surface s, including: Calculate the sliding surface s using the following formula. c is the correction constant.

[0013] Optionally, establishing a control algorithm model and calculating the control current u of the multi-way valve based on the control algorithm model includes: Calculate the rate of change of actual velocity using the following formula. , , Let J be the rate of change of the actual velocity v, J be the total moment of inertia of the actuator and the transmission mechanism, B be the viscous friction coefficient of the hydraulic system, K be the torque gain of the actuator, and T be the torque of the actuator. load The load torque of the transmission mechanism; according to Calculate the rate of change of the sliding surface s. For the sign function switching term, when s is greater than 0, The value is 1 when s is less than 0. -1, where k is the gain of the exponential approach term; According to the above as well as The calculated control current u is: .

[0014] Optionally, determining whether the target operating state has been reached based on the actual operating state of the actuator includes: according to Calculate the sliding surface s; Determine if the sliding surface s is 0. If so, maintain the current control current u and return to obtain the actual speed v of the actuator and the target speed v of the conveyor. ref If not, proceed to the next step; The actual speed v of the actuator is reacquired and the sliding surface s is recalculated based on the updated speed error e. The process then returns to the step of determining whether the sliding surface s meets the target operating state determination conditions.

[0015] Optionally, after each control cycle, the actual speed v and the target speed v of the actuator are recorded. ref Speed ​​error e, speed error change rate The control current u, the feedback pressure of the load-sensitive feedback oil circuit, and the output pressure of the variable pump.

[0016] A construction device comprising the hydraulic system described in any one of the preceding claims.

[0017] The hydraulic system provided by this invention includes a power source, a variable pump, a multi-way valve, an actuator, a controller, a load-sensitive feedback oil circuit, and a pressure dynamic correction mechanism. The variable pump is connected to the power source; the multi-way valve is connected to the output end of the variable pump; the actuator is connected to the output end of the multi-way valve and is used to drive the transmission mechanism; the controller controls the operation of the multi-way valve according to the operating state of the actuator; the load-sensitive feedback oil circuit is connected between the multi-way valve and the variable pump; the pressure dynamic correction mechanism is connected to the load-sensitive feedback oil circuit; the pressure dynamic correction mechanism includes at least two throttling branches respectively connected to different pressure nodes, and the at least two throttling branches automatically distribute the hydraulic oil flow based on the pressure difference formed at both ends to change the feedback pressure in the load-sensitive feedback oil circuit and dynamically correct the pressure compensation signal of the variable pump.

[0018] In actual construction, the power source drives the variable pump to establish hydraulic pressure. The variable pump continuously outputs hydraulic oil to the multi-way valve. The multi-way valve adjusts the valve core opening according to the control current output by the controller, and delivers hydraulic oil with corresponding pressure and flow to the actuator. The actuator drives the transmission mechanism to run at the target speed. The controller collects the operating status of the actuator in real time and continuously adjusts the control current of the multi-way valve according to the operating status to keep the actuator's output stable. When the load of the transmission mechanism changes, the load-sensitive feedback oil circuit transmits the feedback pressure to the variable pump. At the same time, the pressure dynamic correction mechanism automatically adjusts the hydraulic oil flow in each throttling branch according to the pressure difference formed between different pressure nodes, dynamically correcting the load-sensitive feedback pressure. When the load decreases, the feedback pressure increases, and the hydraulic oil preferentially flows to the oil tank through the corresponding throttling branch, causing the feedback pressure to decrease rapidly, and the variable pump reduces its displacement in time. When the load increases, the variable pump increases its output pressure and flow, thereby ensuring the continuous and stable operation of the actuator and improving the hydraulic system's adaptability to load changes.

[0019] This invention incorporates a dynamic pressure correction mechanism within the load-sensitive feedback oil circuit. This mechanism enables each throttling branch to automatically distribute hydraulic oil flow based on the pressure difference between different pressure nodes, achieving real-time dynamic correction of the feedback pressure without the need for additional electro-hydraulic actuators. When a sudden load change occurs, the dynamic pressure correction mechanism quickly adjusts the load-sensitive feedback pressure, allowing the variable pump to promptly correct its output pressure and flow, effectively reducing feedback pressure overshoot, pressure hysteresis, and flow fluctuations, thus improving the variable pump's response quality to load changes. Simultaneously, the dynamic pressure correction mechanism acts as a hydraulic filter for high-frequency pressure pulsations in the feedback oil circuit, reducing pressure oscillations and hydraulic shocks, and improving system operational stability. Furthermore, this dynamic pressure correction mechanism works in synergy with the controller, ensuring stable output speed of the actuator while enhancing the hydraulic system's anti-interference capability, control accuracy, and dynamic response performance under complex operating conditions. The overall structure is simple, requiring no additional complex electro-hydraulic control components, and offers advantages such as high reliability, strong adaptability, and ease of engineering application. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 This is a partial structural schematic diagram of the hydraulic system provided by the present invention.

[0022] Figure 2This is a schematic diagram of the trajectory of the actual velocity v versus the position.

[0023] Figure 3 This is a flowchart illustrating a specific embodiment of the anti-interference control method for hydraulic systems provided by the present invention.

[0024] Figures 1-3 middle: 1 is the power source, 2 is the variable pump, 3 is the multi-way valve, 4 is the load-sensitive feedback oil circuit, 5 is the pressure dynamic correction mechanism, 51 is the first throttle valve, and 52 is the second throttle valve. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The core of this invention is to provide a hydraulic system that avoids problems such as delayed feedback pressure regulation, insufficient anti-interference ability, low control accuracy, and poor system stability under sudden load changes.

[0027] Another core aspect of this invention is to provide a hydraulic system anti-interference control method applied to the aforementioned hydraulic system, as well as a construction device including the aforementioned hydraulic system.

[0028] like Figure 1 As shown, this embodiment provides a hydraulic system including a power source 1, a variable displacement pump 2, a multi-way valve 3, an actuator, a controller, a load-sensitive feedback oil circuit 4, and a pressure dynamic correction mechanism 5. The power source 1 provides mechanical power to the entire hydraulic system and can be a diesel engine, an electric motor, or other power device capable of continuous power output. The power source 1 is connected to the variable displacement pump 2 to drive it to establish hydraulic pressure and continuously output hydraulic oil. The output end of the variable displacement pump 2 is connected to the multi-way valve 3, which adjusts the hydraulic oil output direction, output pressure, and output flow rate according to the control signal output by the controller, and provides hydraulic oil to the actuator to meet the operating conditions. The actuator is preferably a hydraulic motor, which is connected to a conveying mechanism to drive a conveyor belt, chain conveyor, or other conveying mechanism to operate stably, enabling continuous material conveying.

[0029] The controller is connected to both the actuator and the multi-way valve 3. It collects the real-time operating status of the actuator and controls the multi-way valve 3 based on the collected data, ensuring the actuator maintains a near-target operating state. The controller can acquire the actual speed, operating trend, and system feedback status of the actuator in real time, and continuously adjusts the control current of the multi-way valve 3 according to the control algorithm, thereby achieving closed-loop control of the hydraulic system. The load-sensitive feedback oil circuit 4 is connected between the multi-way valve 3 and the variable pump 2. It transmits the feedback pressure generated by the current load change of the actuator to the variable pump 2, enabling the variable pump 2 to automatically adjust its displacement and output pressure based on the feedback pressure, thus improving the energy efficiency of the hydraulic system.

[0030] The pressure dynamic correction mechanism 5 is connected to the load-sensitive feedback oil circuit 4. The pressure dynamic correction mechanism 5 includes at least two throttling branches that are respectively connected to different pressure nodes. Each throttling branch automatically distributes the hydraulic oil flow based on the pressure difference formed at both ends. When the feedback pressure in the load-sensitive feedback oil circuit 4 changes, each throttling branch can automatically change the flow distribution ratio according to the pressure difference to correct the feedback pressure in real time, so that the variable pump 2 receives a pressure compensation signal that is closer to the actual load state.

[0031] In practical use, power source 1 starts and continuously outputs power, driving variable pump 2 to establish initial hydraulic pressure. Variable pump 2 continuously outputs hydraulic oil with a certain pressure and flow rate to multi-way valve 3. The controller controls the operation of multi-way valve 3 according to the equipment's preset operating parameters. Multi-way valve 3 delivers hydraulic oil to the actuator, which drives the conveyor mechanism to start conveying materials. As the conveyor mechanism continues to operate, the controller continuously acquires the actual operating status of the actuator and continuously corrects the control quantity of multi-way valve 3 based on the operating status, ensuring stable output from the actuator. When the amount of material conveyed is small or the material suddenly leaves the conveyor mechanism, the load on the actuator decreases rapidly, and the feedback pressure in the load-sensitive feedback oil circuit 4 changes accordingly. The pressure dynamic correction mechanism 5 automatically adjusts the internal hydraulic oil flow rate based on the pressure difference between each pressure node, allowing the feedback pressure to quickly approach the actual load pressure. Variable pump 2 promptly reduces its displacement and output pressure based on the corrected feedback pressure to avoid maintaining a high output state. When a large amount of material enters the conveying mechanism or the external resistance suddenly increases, the load on the actuator increases rapidly. The feedback pressure in the load-sensitive feedback oil circuit 4 changes again, and the pressure dynamic correction mechanism 5 automatically redistributes the hydraulic oil flow, so that the variable pump 2 can increase the output pressure and flow in time, ensuring that the actuator continuously provides sufficient driving force and avoiding a significant decrease or even stagnation in the speed of the conveying mechanism.

[0032] This embodiment adds a dynamic pressure correction mechanism 5 to the load-sensitive feedback oil circuit 4, enabling the hydraulic system to retain the advantages of traditional load-sensitive control while further enhancing its dynamic pressure correction capability. When the actuator is subjected to external disturbances, the dynamic pressure correction mechanism 5 automatically distributes the hydraulic oil flow based on the pressure difference formed by different pressure nodes, allowing the feedback pressure to quickly approach the actual load pressure. This reduces the adverse effects of feedback pressure lag, pressure overshoot, and pressure fluctuations on the variable pump 2, thereby improving the accuracy of the variable pump 2's displacement adjustment and its response quality to load changes. Simultaneously, the dynamic pressure correction mechanism 5 reduces hydraulic shocks caused by sudden load changes, minimizes system pressure oscillations, stabilizes the output of the multi-way valve 3, significantly reduces speed fluctuations in the actuator, and ensures continuous and stable operation of the transmission mechanism. Since the entire pressure correction process is mainly completed automatically based on the internal pressure difference of the hydraulic network, no additional complex actuators or control units are required. Therefore, the overall structure is simple, highly reliable, and has a low failure rate, facilitating long-term continuous operation of engineering machinery.

[0033] Based on the above embodiments, such as Figure 1 As shown, the pressure dynamic correction mechanism 5 includes a first throttling branch and a second throttling branch. One end of the first throttling branch is connected to the load-sensitive feedback oil circuit 4, and the other end is connected to the oil tank, used to establish a pressure relief path when the feedback pressure is higher than the set range; one end of the second throttling branch is connected to the variable pump 2, and the other end is connected to the load-sensitive feedback oil circuit 4, used to establish a pressure transmission channel between the variable pump 2 and the load-sensitive feedback oil circuit 4. The first throttling branch and the second throttling branch together form a bridge-type hydraulic resistance network, which automatically adjusts the hydraulic oil flow in each throttling branch through the pressure difference formed between different pressure nodes, thereby changing the feedback pressure in the load-sensitive feedback oil circuit 4.

[0034] The bridge-type hydraulic resistance network utilizes the pressure difference naturally formed between different pressure nodes of hydraulic oil as the driving force, achieving automatic flow distribution without the need for additional electronic control actuators. When the feedback pressure in the load-sensitive feedback oil circuit 4 changes, the internal hydraulic resistance relationship of the first and second throttling branches changes synchronously, allowing the hydraulic oil to automatically select the flow path with less resistance, thus achieving real-time adjustment of the feedback pressure. The bridge-type hydraulic resistance network not only establishes a rapid feedback pressure adjustment channel but also forms stable hydraulic damping, improving the continuity and smoothness of the feedback pressure transmission process, avoiding frequent large-scale displacement changes in the variable pump 2, and improving the overall dynamic performance of the hydraulic system. This embodiment mainly limits the composition and connection relationship of the bridge-type hydraulic resistance network, without further limiting the specific structural form of the throttling elements inside the bridge-type hydraulic resistance network, providing a basis for further limiting the specific structure in subsequent embodiments.

[0035] In practical use, when the conveying mechanism maintains stable conveying, the load-sensitive feedback oil circuit 4 continuously feeds back the load pressure to the variable pump 2. At this time, the throttling branches inside the bridge-type hydraulic resistance network are in a dynamic equilibrium state. The first and second throttling branches work together to maintain stable transmission of feedback pressure, ensuring that the variable pump 2 maintains an output pressure and output flow rate that matches the current load. When the conveyed material suddenly decreases, the feedback pressure tends to increase, the pressure difference between the two ends of the first throttling branch increases rapidly, and the hydraulic oil automatically flows to the oil tank through the first throttling branch. The bridge-type hydraulic resistance network redistributes the hydraulic oil flow, causing the feedback pressure in the load-sensitive feedback oil circuit 4 to drop rapidly, and the variable pump 2 reduces its displacement in time. When the load on the conveying mechanism increases again, the second throttling branch assumes the main pressure transmission role, and the hydraulic oil flows back to the load-sensitive feedback oil circuit 4. The bridge-type hydraulic resistance network re-establishes a new pressure equilibrium state, enabling the variable pump 2 to quickly increase its output pressure and output flow rate, ensuring that the actuator continuously and stably drives the conveying mechanism. Throughout the entire adjustment process, the bridge-type liquid resistance network automatically redistributes the flow based on the pressure difference formed by different pressure nodes, eliminating the need for a controller to directly control the throttling branch, thereby reducing control complexity and improving system reliability.

[0036] This embodiment upgrades the pressure dynamic correction mechanism 5 from a single pressure relief structure to a hydraulic balance network capable of automatic flow distribution by constructing the first and second throttling branches into a bridge-type hydraulic resistance network. When the load changes, each throttling branch can automatically establish the optimal hydraulic flow path based on the pressure difference, achieving continuous correction of the feedback pressure. This effectively reduces the pressure lag phenomenon of the traditional load-sensitive feedback oil circuit 4 and improves the timeliness of the displacement adjustment of the variable pump 2. At the same time, the bridge-type hydraulic resistance network has a certain hydraulic buffering and damping effect, which can effectively absorb high-frequency pressure pulsations in the feedback pressure, reduce the pressure shock caused by frequent adjustments of the variable pump 2, and improve the smoothness of the hydraulic system operation. In addition, since the bridge-type hydraulic resistance network relies on the pressure of the hydraulic circuit itself to complete the adjustment, it does not depend on a complex electronic control unit. Therefore, it has a simple structure, high reliability, and convenient maintenance, making it suitable for mobile crushing and screening equipment, mining machinery, and other hydraulic systems with frequently changing loads.

[0037] Based on the above embodiments, the bridge-type liquid resistance network is further implemented using a C-type half-bridge structure; such as Figure 1 As shown, the C-type half-bridge includes a first throttle valve 51 and a second throttle valve 52; the first throttle valve 51 and the second throttle valve 52 are respectively connected to different pressure nodes, wherein the first throttle valve 51 is preferably arranged between the load-sensitive feedback oil circuit 4 and the oil tank, and the second throttle valve 52 is preferably arranged between the variable pump 2 and the load-sensitive feedback oil circuit 4; the first throttle valve 51 and the second throttle valve 52 together form a C-type half-bridge hydraulic network with different hydraulic resistance characteristics.

[0038] When the pressure changes between different pressure nodes, different pressure differences are formed at the ends of the first throttle valve 51 and the second throttle valve 52. The hydraulic oil automatically selects the flow path according to the magnitude of the pressure difference and the change in hydraulic resistance, thereby changing the feedback pressure in the load-sensitive feedback oil circuit 4, so that the variable pump 2 receives a more accurate pressure compensation signal.

[0039] After the equipment enters normal operating mode, power source 1 drives variable pump 2 to continuously supply oil, and multi-way valve 3 controls the actuator to stably drive the conveying mechanism. When the weight of the material changes, the pressure in the load-sensitive feedback oil circuit 4 fluctuates accordingly, and the pressure difference between the first throttle valve 51 and the second throttle valve 52 changes synchronously. When the feedback pressure rises rapidly, the first throttle valve 51 forms a large leakage capacity, allowing some of the feedback oil to flow quickly to the oil tank, reducing the feedback pressure in the load-sensitive feedback oil circuit 4 and preventing variable pump 2 from continuing to maintain high displacement output. At the same time, the second throttle valve 52 maintains the necessary pressure transmission between variable pump 2 and load-sensitive feedback oil circuit 4, keeping the feedback signal continuous and stable. When the load increases again, the leakage flow of the first throttle valve 51 decreases, and the second throttle valve 52 assumes the main pressure transmission role, enabling variable pump 2 to quickly increase its output pressure and flow rate.

[0040] This embodiment employs a C-type half-bridge structure composed of a first throttle valve 51 and a second throttle valve 52, which offers superior dynamic pressure correction capabilities compared to a conventional bridge-type hydraulic resistance network. On one hand, the C-type half-bridge can automatically adjust the hydraulic resistance ratio based on the pressure difference between different pressure nodes, ensuring the feedback pressure remains close to the actual load pressure, reducing pressure overshoot and pressure hysteresis, and improving the displacement adjustment accuracy of the variable pump 2. On the other hand, the first throttle valve 51 and the second throttle valve 52 together form a hydraulic low-pass filter network, which can continuously weaken high-frequency pressure pulsations and hydraulic shocks, reducing mechanical wear caused by frequent adjustments of the variable pump 2 and extending the service life of hydraulic components.

[0041] Based on the above embodiments, such as Figure 1 As shown, the first throttle valve 51 adopts an adjustable flow valve structure, and its throttling area can automatically change according to the pressure difference between the two ends, thereby changing the hydraulic oil flow rate in the first throttling branch. The first throttle valve 51 can adopt a cone valve type throttling structure, a slide valve type throttling structure, or other hydraulic throttling elements with continuous adjustment capability.

[0042] When the load on the transmission mechanism decreases, the load torque on the actuator decreases synchronously. Since the variable pump 2 maintains its original output state, the feedback pressure in the load-sensitive feedback oil circuit 4 will be higher than the actual load pressure for a short period of time, resulting in a large pressure difference between the two ends of the first throttling branch. At this time, the first throttling valve 51 automatically increases the effective flow area, allowing more hydraulic oil to flow to the oil tank through the first throttling branch. The feedback pressure in the load-sensitive feedback oil circuit 4 decreases rapidly, causing the variable pump 2 to reduce its displacement and output flow in a timely manner. When the load on the transmission mechanism increases again, the pressure difference between the two ends of the first throttling branch decreases, the first throttling valve 51 automatically reduces the flow area, and the bridge hydraulic resistance network re-establishes a new pressure balance. The variable pump 2 increases its output pressure and output flow based on the re-established feedback pressure to meet the new power requirements of the actuator.

[0043] In actual use, when the conveying mechanism is operating at full load, the first throttle valve 51 maintains a small leakage state, and the feedback pressure in the load-sensitive feedback oil circuit 4 is stably transmitted to the variable pump 2, enabling the variable pump 2 to continuously output a large pressure and flow rate, ensuring that the actuator can overcome the large load resistance and operate stably. When the material on the conveying mechanism is suddenly unloaded or the heavy object leaves the conveying mechanism, the load on the actuator drops rapidly, but the feedback pressure in the load-sensitive feedback oil circuit 4 remains at a high level for a short period of time. After detecting a rapid increase in the pressure difference between the two ends of the first throttle branch, the first throttle valve 51 automatically expands the throttle channel, and the hydraulic oil flows quickly to the oil tank, causing the feedback pressure to drop rapidly. The variable pump 2 promptly reduces its displacement to avoid continuing to output excessive hydraulic power to the system. When new material re-enters the conveying mechanism, the load on the actuator increases again, the first throttle valve 51 gradually returns to a smaller opening, the bridge hydraulic resistance network re-establishes pressure balance, and the variable pump 2 increases its output pressure and flow rate, enabling the actuator to maintain stable output.

[0044] In this embodiment, by setting the first throttle valve 51 as an adjustable flow valve, the pressure dynamic correction mechanism 5 possesses continuously variable hydraulic resistance characteristics. Compared to a fixed throttle structure, it can more accurately match different load change conditions. When the load decreases, the first throttle valve 51 can quickly establish a pressure relief path, shorten the feedback pressure recovery time, and reduce the lag in the displacement adjustment of the variable pump 2. When the load increases, the first throttle valve 51 can promptly reduce the discharge flow, ensuring that the variable pump 2 quickly restores its oil supply capacity, thereby improving the overall response speed of the hydraulic system.

[0045] In addition to the aforementioned hydraulic system, this invention also provides a hydraulic system anti-interference control method applicable to the hydraulic system disclosed in the above embodiments, such as... Figure 3 As shown, the anti-interference control method for this hydraulic system includes: Step S1: Obtain the actual speed v of the actuator and the target speed v of the transmission mechanism. ref.

[0046] In step S1, the actual speed v can be acquired by a speed sensor installed on the output shaft of the actuator, or it can be obtained by an encoder, speed measuring device, or other speed detection device. Target speed v ref The construction tasks can be preset or adjusted in real time according to the control instructions from the host computer.

[0047] It should be noted that in step S1, the actuator is used to drive the conveyor mechanism to perform the conveying action. In this step, the actual speed v of the actuator and the target speed v of the conveyor mechanism are collected. ref The main purpose is to obtain the difference between the output speed of the actuator and the actual speed of the transmission mechanism. Both can be linear velocities, and the error needs to be calculated after converting them into the same speed quantity through transmission ratio, drum radius, etc.

[0048] Step S2, based on the actual speed v and the target speed v ref Calculate the speed error e, and based on the speed error e and the rate of change of the speed error... Create the sliding surface s.

[0049] In step S2, the sliding surface is used to comprehensively reflect the deviation between the current operating state of the system and the target state, providing a control basis for the subsequent control algorithm. When the sliding surface gradually approaches zero, it indicates that the operating state of the actuator is gradually approaching the target state.

[0050] Step S3: Establish a control algorithm model and calculate the control current u of the multi-way valve based on the control algorithm model.

[0051] Step S4: Control the multi-way valve to adjust the pressure and flow rate of the hydraulic oil output to the actuator according to the control current u.

[0052] In step S4, after the control current u is output to the multi-way valve 3, the multi-way valve 3 adjusts the valve core opening to change the pressure and flow rate of the hydraulic oil entering the actuator, thereby adjusting the output torque and actual speed of the actuator.

[0053] Step S5: Determine whether the target operating state has been reached based on the actual operating state of the actuator. If the target operating state has not been reached, recalculate the control current u and continue to adjust the multi-way valve. If the target operating state has been reached, maintain the current control current u and periodically check the actual operating state of the actuator to form a closed-loop control.

[0054] In actual use, the controller first reads the target speed v set for the construction task. ref It also collects the current actual speed v of the actuator in real time. When the conveyor mechanism just starts running, due to inertia, the actual speed v and the target speed v are different.ref There is usually a certain deviation between the speed and the flow rate. The controller first calculates the speed error e, then establishes the sliding surface s based on the speed change trend, and quickly calculates the control current u according to the control algorithm. The multi-way valve 3 adjusts the valve core opening accordingly, so that the output of the variable pump 2 is more in line with the pressure and flow rate of the current working condition. As the actuator continues to operate, the controller repeatedly collects speed data, calculates the speed error e, calculates the control current, adjusts the multi-way valve, and checks again in this closed-loop process. When the weight of the material on the conveying mechanism changes continuously, the actuator is affected by external disturbances, and the actual speed may fluctuate for a short time. The controller immediately recalculates the new control current u, so that the multi-way valve 3 quickly adjusts the oil supply pressure and flow rate, prompting the actuator to restore the target speed. When the sliding surface s gradually approaches zero, it indicates that the system has entered a stable operating state. At this time, the controller maintains the current control current u output and only periodically checks the actual operating state. When load disturbances occur again, the system immediately enters the next round of dynamic adjustment to achieve continuous anti-interference control.

[0055] This embodiment employs a hydraulic system anti-interference control method based on sliding mode control. It collects real-time data on the operating status of the actuator and adjusts the control based on the speed error e and the rate of change of error. By establishing a sliding surface, the controller can accurately reflect the degree to which the system deviates from the target state, exhibiting faster convergence speed and stronger robustness compared to traditional PID control. When sudden changes in material weight, hydraulic load fluctuations, or external impacts occur during construction, the controller can quickly calculate the new control current u and drive the multi-way valve 3 to adjust the hydraulic oil pressure and flow in a timely manner, enabling the actuator to quickly return to the target operating state and effectively reducing speed overshoot and steady-state deviation. Simultaneously, this method, together with the pressure dynamic correction mechanism 5, forms a hardware-software collaborative control system. The software layer performs real-time correction of the control strategy, while the hardware layer dynamically optimizes the feedback pressure of the load-sensitive feedback oil circuit 4. Together, they improve the dynamic response capability, anti-interference capability, and control accuracy of the hydraulic system, ensuring that the construction equipment maintains stable, efficient, and continuous operation even under complex working conditions.

[0056] Based on the above embodiments, step S2 includes: Step S21, calculate the speed error e according to the following formula, .

[0057] Step S22, calculate the sliding surface s according to the following formula, c is the correction constant.

[0058] in, represents the rate of change of speed error, reflecting how quickly the speed error e changes with time; c represents the correction constant, used to adjust the relationship between error e and the rate of change of error. The weighting ratio between them. The correction constant c can be set according to the inertia of the actuator, the system response speed, and the construction conditions, so that the system can balance fast response and stable operation.

[0059] The controller continuously calculates the sliding surface s and uses it as an important evaluation parameter for the current operating state of the system. For example... Figure 2 As shown, when the sliding surface s gradually approaches zero, it indicates that the operating state of the actuator is continuously approaching the target operating state; when the sliding surface s deviates from zero, it indicates that the system is affected by external load disturbances or changes in internal parameters, requiring further control correction. This is achieved by comparing the speed error e with the error change rate. By constructing a sliding surface together, rather than controlling solely based on speed error, the system can predict speed change trends in advance, thereby improving the dynamic control performance of the hydraulic system.

[0060] As long as the system state, i.e. the current actual velocity v and error e, falls within the range of... Figure 2 On the track shown, the actual speed v smoothly slides towards the target value along the track, that is, the error e is 0, and the actual rotational speed v equals the target rotational speed v. ref .

[0061] The controller first reads the target velocity v ref The actual speed v of the actuator is collected in real time by a speed detection device. When the equipment starts under no-load, due to inertia, the actual speed gradually approaches the target speed. The controller continuously calculates the speed error e and further calculates the rate of change of the speed error. When the error is large, the sliding surface s increases synchronously, and the controller determines that the system is still in the adjustment phase; as the variable pump 2, multi-way valve 3, and actuator continuously adjust their outputs, the speed error e gradually decreases, and the error change rate... As the load decreases synchronously, the sliding surface s gradually converges towards zero. When the conveyor belt suddenly enters a heavy-load condition, the speed of the actuator drops briefly, and the speed error e immediately increases. The controller recalculates the new sliding surface s and initiates subsequent control algorithms based on the changing trend of the sliding surface s, enabling the system to quickly recover the target speed. Once the load stabilizes again, the speed error e gradually decreases, and the sliding surface s approaches zero again. The entire process is continuously cyclical, ensuring that the hydraulic system maintains a stable closed-loop operating state.

[0062] This embodiment uses the speed error e and the rate of change of speed error. By jointly establishing a sliding surface s, the controller can not only reflect the current error magnitude but also predict the changing trend of the error e. Compared to traditional methods that rely solely on the speed error e for control, this approach offers superior dynamic response capabilities. When the load changes rapidly during construction, the sliding surface s can promptly reflect the degree of system deviation from the target state, providing an accurate basis for subsequent control law calculations and improving the hydraulic system's resistance to disturbances. Simultaneously, the correction constant c can be adjusted according to different equipment parameters, making the control strategy applicable to various construction equipment specifications and enhancing the algorithm's versatility and engineering applicability.

[0063] Based on the above embodiments, step S3 includes: Step S31: Calculate the rate of change of the actual velocity according to the following formula. , , Let J be the rate of change of the actual velocity v, J be the total moment of inertia of the actuator and the transmission mechanism, B be the viscous friction coefficient of the hydraulic system, K be the torque gain of the actuator, and T be the torque of the actuator. load The load torque of the transmission mechanism is given.

[0064] , The driving torque of the actuator; Step S32, according to Calculate the rate of change of the sliding surface s. For the sign function switching term, when s is greater than 0, The expression is 1; when s equals 0, sgn(s) is 0; when s is less than 0, =-1; k is the gain of the exponential approach term, and k is greater than zero; ε is the switching gain that is greater than zero.

[0065] Step S33, according to the above as well as The calculated control current u is: .

[0066] The controller establishes a sliding mode reaching law based on the hydraulic system dynamics model, and constructs the control law through a sign function switching term and an exponential reaching term. The sign function is used to quickly resist external disturbances; it outputs positive control when the sliding surface s is greater than zero and reverse control when s is less than zero, ensuring the system always converges towards the sliding surface. The exponential reaching term is used to improve the sliding surface convergence speed and reduce the system's steady-state deviation. Finally, the controller calculates the control current u based on the dynamics model, the sliding mode reaching law, and system parameters, and outputs it to the multi-way valve 3. This causes the multi-way valve 3 to adjust the valve core opening, further regulating the pressure and flow rate output from the variable pump 2 to the actuator.

[0067] This embodiment establishes a complete hydraulic system dynamic model, incorporating factors such as the inertia of the actuator, system friction, and load torque into the control model. This enables the controller to accurately reflect the actual operating state of the hydraulic system and improves the accuracy of control current calculation. Simultaneously, the system can quickly establish reverse compensation control when external loads change abruptly, effectively improving anti-interference capabilities and shortening system recovery time. The exponential approach term further reduces sliding mode chattering, improves control smoothness, makes the action of the multi-way valve 3 smoother, reduces hydraulic shock and mechanical wear, improves the long-term reliability of the hydraulic system, and further leverages the dynamic optimization effect of the pressure dynamic correction mechanism 5 on the load-sensitive feedback oil circuit 4, achieving coordinated control between the software algorithm and the hydraulic structure.

[0068] Based on the above embodiments, step S5 includes: Step S51, according to Calculate the sliding surface s.

[0069] Step S52: Determine whether the sliding surface s is 0. If so, maintain the current control current u and return to obtain the actual speed v of the actuator and the target speed v of the transmission mechanism. ref If not, proceed to step S53.

[0070] Step S53: Reacquire the actual speed v of the actuator and recalculate the sliding surface s based on the updated speed error e, and return to step S52.

[0071] The controller continuously performs detection, calculation, and control according to a preset sampling cycle. When the actuator reaches the target speed, the sliding surface s gradually approaches zero, and the controller maintains the current control current u output to keep the hydraulic system in a stable operating state. If, during construction, a large piece of material suddenly enters the conveyor belt, the equipment climbs an incline, or other external disturbances occur, the speed of the actuator immediately changes, and the sliding surface s synchronously deviates from zero. The controller quickly identifies that the system has deviated from a stable state and immediately reacquires the latest speed information, recalculates the control current u, and the multi-way valve 3 adjusts the oil supply pressure and flow rate to restore the actuator to the target speed. When the system stabilizes again, the sliding surface s approaches zero again, and the controller continues to maintain the current control state. This process is continuously repeated, enabling the hydraulic system to continuously adapt to complex construction environments.

[0072] This embodiment uses the sliding surface s as the criterion for whether the system has reached the target state, enabling the controller to judge the stability of the hydraulic system in real time and automatically switch between maintaining control and readjusting control based on the judgment result. This is more intelligent and efficient than fixed-time control. When the system is disturbed, it can re-enter the control process without waiting for a long time, significantly shortening the response time and improving the speed stability of the actuator. At the same time, the system only recalculates the control current u when adjustment is needed, maintaining the current output during the stable phase. This reduces the computational burden on the controller and the frequent operation of the multi-way valve 3, improves the service life of hydraulic components, and further enhances the control accuracy, dynamic response performance, and anti-interference capability of the entire hydraulic system.

[0073] Based on the above embodiments, the hydraulic system anti-interference control method further includes recording the actual speed v and target speed v of the actuator after each control cycle. ref Speed ​​error e, speed error change rate The control current u, the feedback pressure of the load-sensitive feedback oil circuit 4, and the output pressure of the variable pump 2.

[0074] At the end of a control cycle, the controller immediately records all key operating parameters for that cycle and stores them in the storage module. As construction continues, data from each control cycle accumulates to form a complete operating curve. When the equipment experiences sudden load changes, speed fluctuations, or pressure anomalies, the controller can immediately retrieve data from multiple adjacent control cycles for analysis, determine the cause of the anomaly, and adjust the control strategy based on historical operating patterns. After the equipment completes its construction task, personnel can also read historical operating data to analyze the overall operating status of the hydraulic system, further optimizing sliding form control parameters, dynamic pressure correction parameters, and variable pump control parameters to achieve more stable control results in the next construction operation.

[0075] This embodiment establishes a complete operational data recording mechanism, enabling the hydraulic system to not only possess real-time control capabilities but also operational status traceability, control effect evaluation, and continuous parameter optimization capabilities. By accumulating actual operational data over a long period, the controller can continuously refine the control model, improving the sliding mode control algorithm's adaptability to different construction conditions. Simultaneously, by recording the feedback pressure of the load-sensitive feedback oil circuit 4 and the output pressure of the variable pump 2, it can promptly detect potential faults such as abnormal pressure, hydraulic leakage, or component performance degradation, thereby improving the reliability of the hydraulic system.

[0076] In addition to the hydraulic system described above, the present invention also provides a construction device that includes the hydraulic system disclosed in the above embodiments.

[0077] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Any combination of all embodiments provided by this invention is within the scope of protection of this invention and will not be elaborated upon here.

[0078] The present invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A hydraulic system, characterized in that, include: Power source (1); A variable pump (2) is connected to the power source (1); A multi-way valve (3) is connected to the output end of the variable pump (2); An actuating power mechanism is connected to the output end of the multi-way valve (3), and the actuating power mechanism is used to drive the transmission mechanism to operate; The controller is used to control the operation of the multi-way valve (3) according to the operating status of the actuator; The load-sensitive feedback oil circuit (4) is connected between the multi-way valve (3) and the variable pump (2); The pressure dynamic correction mechanism (5) is connected to the load-sensitive feedback oil circuit (4); the pressure dynamic correction mechanism (5) includes at least two throttling branches that are respectively connected to different pressure nodes. The at least two throttling branches automatically distribute hydraulic oil flow based on the pressure difference formed at both ends, so as to change the feedback pressure in the load-sensitive feedback oil circuit (4) and dynamically correct the pressure compensation signal of the variable pump (2). The pressure dynamic correction mechanism (5) includes a first throttling branch and a second throttling branch. One end of the first throttling branch is connected to the load-sensitive feedback oil circuit (4), and the other end is connected to the oil tank. One end of the second throttling branch is connected to the variable pump (2), and the other end is connected to the load-sensitive feedback oil circuit (4). The first throttling branch and the second throttling branch form a bridge-type hydraulic resistance network, which is used to automatically adjust the hydraulic oil flow rate in each throttling branch according to the pressure difference formed between different pressure nodes; The bridge-type hydraulic resistance network is a C-type half-bridge. The C-type half-bridge includes a first throttle valve (51) and a second throttle valve (52). The first throttle valve (51) and the second throttle valve (52) are respectively connected to different pressure nodes. When the pressure between each pressure node changes, the hydraulic oil automatically selects the flow path according to the pressure difference formed at both ends of each throttle valve, so as to dynamically correct the feedback pressure of the load-sensitive feedback oil circuit (4). The first throttle valve (51) is located between the load-sensitive feedback oil circuit (4) and the oil tank, and the second throttle valve (52) is located between the load-sensitive feedback oil circuit (4) and the variable pump (2).

2. The hydraulic system according to claim 1, characterized in that, The first throttle valve (51) is an adjustable flow valve; When the load on the transmission mechanism decreases, the feedback pressure in the load-sensitive feedback oil circuit (4) increases, and the pressure difference between the two ends of the first throttling branch increases; the hydraulic oil preferentially flows to the oil tank through the first throttling branch to reduce the feedback pressure; When the load on the transmission mechanism increases, the pressure difference between the two ends of the first throttling branch decreases, and the bridge-type liquid resistance network re-establishes pressure balance, thereby increasing the output pressure and flow of the variable pump (2).

3. A method for anti-interference control of a hydraulic system, characterized in that, The hydraulic system anti-interference control method, applied to the hydraulic system according to claim 1 or 2, includes: Obtain the actual speed v of the actuator and the target speed v of the transmission mechanism. ref ; Based on the actual speed v and the target speed v ref Calculate the speed error e, and based on the speed error e and the rate of change of the speed error... Establish the sliding surface s; Establish a control algorithm model, and calculate the control current u of the multi-way valve (3) based on the control algorithm model; The control current u controls the multi-way valve (3) to regulate the pressure and flow rate of the hydraulic oil output to the actuator; The target operating state is determined based on the actual operating state of the actuator. If the target operating state is not reached, the control current u is recalculated and the multi-way valve (3) is adjusted. If the target operating state is reached, the current control current u is maintained and the actual operating state of the actuator is periodically detected to form a closed-loop control.

4. The anti-interference control method for a hydraulic system according to claim 3, characterized in that, The actual speed v and the target speed v are used as the basis ref The speed error e is calculated, including: Calculate the speed error e using the following formula. ; The speed error e and the rate of change of speed error are based on the speed error e. Establish the sliding surface s, including: Calculate the sliding surface s using the following formula. c is the correction constant.

5. The anti-interference control method for a hydraulic system according to claim 4, characterized in that, The establishment of the control algorithm model and the calculation of the control current u of the multi-way valve (3) based on the control algorithm model include: Calculate the rate of change of actual velocity using the following formula. , , Let J be the rate of change of the actual velocity v, J be the total moment of inertia of the actuator and the transmission mechanism, B be the viscous friction coefficient of the hydraulic system, K be the torque gain of the actuator, and T be the torque of the actuator. load The load torque of the transmission mechanism; according to Calculate the rate of change of the sliding surface s. For the sign function switching term, when s is greater than 0, The value is 1 when s is less than 0. -1, where k is the gain of the exponential approach term; According to the above as well as The calculated control current u is: 。 6. The anti-interference control method for a hydraulic system according to claim 5, characterized in that, The step of determining whether the target operating state has been reached based on the actual operating state of the actuator includes: according to Calculate the sliding surface s; Determine if the sliding surface s is 0. If so, maintain the current control current u and return to obtain the actual speed v of the actuator and the target speed v of the conveyor. ref If not, proceed to the next step; The actual speed v of the actuator is reacquired and the sliding surface s is recalculated based on the updated speed error e. The process then returns to the step of determining whether the sliding surface s meets the target operating state determination conditions.

7. The anti-interference control method for a hydraulic system according to claim 6, characterized in that, After each control cycle, record the actual speed v and the target speed v of the actuator. ref Speed ​​error e, speed error change rate The control current u, the feedback pressure of the load-sensitive feedback oil circuit (4), and the output pressure of the variable pump (2) are all measured.

8. A construction equipment, characterized in that, Includes the hydraulic system as described in claim 1 or 2.

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