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"Hydraulic control"
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Tillage depth dynamic monitoring and precise control system
The tillage depth (TD) serves as a pivotal criterion for assessing the operational excellence of rotary tillers, yet the current TD control methods are plagued by a myriad of issues including subpar precision and sluggish responsiveness. The present study aimed to develop a high-precision TD monitoring model that incorporates the tilting attitude of the tractor, and investigate the impact of tractor attitude inclination and lifting hydraulic cylinder stroke on TD. The TD stability control system based on electro-hydraulic control was developed, and the model identification method was adopted to derive the accurate control function. The fuzzy adaptive PID (FAPID) method was adopted to effectively improve the response speed and resisting disturbance capacity of the electro-hydraulic system. Then the co-simulation model of the electro-hydraulic control system was constructed. Under the excitation of step and sine functions, the FAPID control algorithm can reduce the rise time by more than 50%, and the displacement tracking error is also effectively reduced. To verify its effectiveness, the experimental platform was constructed, and then field test trials of TD were conducted. The test results indicate that, under various operational conditions, the developed TD control device can effectively reduce the standard deviation of TD by 0.302–0.464 and decrease the variation coefficient of TD by 2.47%–2.92%. The online monitoring and precise control device of TD investigated in this paper can effectively improve the quality of tillage machinery.
Journal Article
Review of Recent Advances in the Drive Method of Hydraulic Control Valve
Hydraulic control valves are widely used in industrial production, agricultural equipment, construction machinery, and other large power equipment for controlling the pressure and flow of fluids in hydraulic systems. The driving method has a significant impact on the response and control accuracy of hydraulic valves. This paper reviews the driving methods of spools from five aspects: solenoid drive, material expansion drive, motor drive, hydraulic valve drive, and another drive. It summarizes the various schemes currently available for spool drive and analyzes each of them. After optimizing the driving method of the valve core, the control accuracy can reach 3%, and the minimum response time is 7 ms. According to the characteristics of the different drive methods, the differences between them are compared, the advantages and disadvantages of each drive method are analyzed, and the application scenarios for each drive method are identified. Solutions to the drawbacks of the existing drive methods are proposed, which provide directions for further optimization. We have found that solenoid drives are simple to control, low cost, and the most widely used. Material telescopic drives, motor drives, hydraulic valve drives, and other drives are costly, complex to control, and optional for use in special requirement situations. Based on the existing spool drive methods, an outlook on future drive methods is presented. This review facilitates a comprehensive understanding of the drive methods of hydraulic valve spools, points out the shortcomings of the existing drive methods, and is of great significance in improving the existing drive methods and proposing new drive methods. This paper has a positive effect on improving the control accuracy and responsiveness of hydraulic valves.
Journal Article
Design of Chaos Induced Aquila Optimizer for Parameter Estimation of Electro-Hydraulic Control System
Aquila Optimizer (AO) is a recently proposed population-based optimization technique inspired by Aquila’s behavior in catching prey. AO is applied in various applications and its numerous variants were proposed in the literature. However, chaos theory has not been extensively investigated in AO. Moreover, it is still not applied in the parameter estimation of electro-hydraulic systems. In this work, ten well-defined chaotic maps were integrated into a narrowed exploitation of AO for the development of a robust chaotic optimization technique. An extensive investigation of twenty-three mathematical benchmarks and ten IEEE Congress on Evolutionary Computation (CEC) functions shows that chaotic Aquila optimization techniques perform better than the baseline technique. The investigation is further conducted on parameter estimation of an electro-hydraulic control system, which is performed on various noise levels and shows that the proposed chaotic AO with Piecewise map (CAO6) achieves the best fitness values of 2.873E−05, 1.014E−04, and 8.728E−03 at noise levels 1.300E−03, 1.300E−02, and 1.300E−01, respectively. Friedman test for repeated measures, computational analysis, and Taguchi test reflect the superiority of CAO6 against the state of the arts, demonstrating its potential for addressing various engineering optimization problems. However, the sensitivity to parameter tuning may limit its direct application to complex optimization scenarios.
Journal Article
Review of the Progress of Energy Saving of Hydraulic Control Systems
In many different industrial domains, hydraulic control systems are extensively utilized. This paper examines the current state of research and the trajectory of energy-efficient hydraulic control system development. Initially, a quick introduction to the control principles of hydraulic control systems is given. Secondly, hydraulic control systems are classified, the factors affecting the energy consumption of hydraulic control systems are analyzed, and the method of reducing its influence on hydraulic control systems is given. Subsequently, research concerning energy conservation is compiled based on the classification of hydraulic control systems. In this paper, the circuit structure of two control modes of a hydraulic control system (valve control system and pump control system) and their related control algorithms (fuzzy PID control, adaptive robust control) for reducing system energy consumption are studied. In summary, the evolution of energy-efficient hydraulic control system approaches is forecasted and projected, offering some pointers for advancing hydraulic control system study and implementation in the industrial future.
Journal Article
Optimized Pilot Hydraulic Valves for Urban Water Systems via Enhanced BP-Coati Algorithms
Hydraulic control valves, positioned at the terminus of pipe networks, are critical for regulating flow and pressure, thereby ensuring the operational safety and efficiency of pipeline systems. However, conventional valve designs often struggle to maintain effective regulation across a wide range of system pressures. To address this limitation, this study introduces a novel Pilot hydraulic valves specifically engineered for enhanced dynamic performance and precise regulation under variable pressure conditions. Building upon prior experimental findings, the proposed design integrates a high-fidelity simulation framework and a surrogate model-based optimization strategy. The study begins by formulating a comprehensive mathematical model of the pipeline system using electro-hydraulic simulation techniques, capturing the dynamic behavior of both the pilot valve and the broader urban water distribution network. A coupled simulation platform is then developed, leveraging both one-dimensional (1D) and three-dimensional (3D) software tools to accurately analyze the valve’s transient response and operational characteristics. To achieve optimal valve performance, a multi-objective optimization approach is proposed. This approach employs a Levy-based Improved Tuna-Inspired Wake-Up Optimization Algorithm (L-TIWOA) to refine a Backpropagation (BP) neural network, thereby constructing a highly accurate surrogate model. Compared to the conventional BP neural network, the improved model demonstrates significantly reduced mean absolute error (MAE) and mean squared error (MSE), underscoring its superior predictive capability. The surrogate model serves as the objective function within an Improved Multi-Objective Mother Lode Optimization Algorithm (IMOMLOA), which is then used to fine-tune the key design parameters of the control valve. Validation through experimental testing reveals that the optimized valve achieves a maximum flow deviation of just 1.11 t/h, corresponding to a control accuracy of 3.7%, at a target flow rate of 30 t/h. Moreover, substantial improvements in dynamic response are observed, confirming the effectiveness of the proposed design and optimization strategy.
Journal Article
An Improved Zero-Flowrate Switching Control Method to Reduce Switching Losses in a Hydraulic Actuator
Hydraulic switching actuators are high-efficiency, fast response, and low-cost solutions for hydraulic control systems. One of the challenging problems is throttling losses during valve transitions. Previously, the authors proposed a zero-flowrate switching method to reduce the throttling energy loss of the switching valve, where a hydraulic resonator is applied to make the flowrates through the lines approaching zero before the valves are switched off. The major challenge of this approach is fast switching valves whose transition times are less than 2 ms. In this paper, an improved zero-flowrate switching method is presented. It utilizes the capacity with independent inlet/outlet ports to regulate flowrates through the lines. Models of capacity applied in a simple line with different pressure signals are developed to explore characteristics of the capacity, based on which a complete actuation system is developed. In the complete model, resistance and inductance are optimized to achieve the desired flowrate response. The improved zero-flowrate switching method reduces throttling energy losses by 99.945% compared to a hard switching system. The simulation results demonstrated that the improved zero-flowrate switching method performs as expected in the design condition. A capacity with proper volume is able to regulate flowrates through all the lines to zero, with the help of appropriate resistance and inductance. Compared to the previous zero-flowrate switching method, the novel strategy allows slower switching valves applied in hydraulic actuation systems and achieves better efficiency performance. This research paves a new avenue for reducing throttling energy losses and improves system efficiency in hydraulic switching actuators, as well as most of the hydraulic switch-mode circuits.
Journal Article
Dynamic Characteristic Optimization of Main Valve in Eight-Speed Auto Transmission Hydraulic Control System
The hydraulic control system has a significant effect on the performance of an automotive transmission system. Conducting a full virtual design and dynamic characteristic optimization of the hydraulic control system parameters during the system development process has a highly significant effect on shortening the development cycle and improving the system performance. This article takes a specific eight-speed auto transmission (8AT) as the control object and, based on the control requirements, principle design of the main circuit, the shift function, and the cooling lubrication system is conducted. In the main pressure regulating circuit, the effect of each structural parameter on the system performance is analyzed by solving the dynamic equations. Further optimal structural parameters for the valve spool are acquired by using a genetic algorithm, and a fluid flow channel simulation the software is Ansys Student 2024 R2 is conducted. The results obtained show that after optimization, the overshoot of the main circuit response is reduced by 18% and the rise time is reduced by 0.08 s; use of the optimal structural parameters of the valve spool can improve the response characteristics significantly.
Journal Article
Study on the relevance between cavitation and cavitation erosion of pure water hydraulic control check valve under the impact of high pressure and large flow
The relationship between impact cavitation characteristics and cavitation damage of a pure water hydraulic control check valve under high pressure and high flow was investigated to prevent cavitation damage. The surface shape, phase, chemical state, and polarization curve of the hydraulic control check valve after pure water impact at high pressure and high flow were analyzed. The results indicate that the greater the impact pressure, the more pronounced the pressure drop at the throttle and the greater and more intense the cavitation range at the flow passage's rear end. Less impact pressure results in a quicker unloading process, and impact pressure has a significant effect on unloading time. With the improvement of impact characteristics, both the cavitation index and cavitation damage intensify. Cavitation collapse can rapidly transfer high temperatures to the surface of stainless steel, resulting in a martensitic structure through the rapid cooling of a pure water medium. After cavitation collapse, the passivation film of the stainless steel surface appears with early cracks and pores, which are more fragile than the surrounding area, resulting in a higher current density in the contained area, resulting in more H
+
in ionization, thus an acidic corrosive solution, and accelerating the destruction of the passivation film.
Journal Article