Hydraulic Control Research Articles

A novel hydraulic load-sensing control solution to working functions of mobile machine

The hydraulic load-sensing system is a more efficient system solution than constant pressure system in mobile machine. However, the overall system efficiency for multiple actuators is still low since this centralized hydraulic control system only adapts to the highest load pressure. Therefore, in this article, a distributed hydraulic control system where each function is powered by a hydraulic free piston engine is proposed. Compared with centralized solution, it is more efficient since the power of hydraulic free piston engine is tailored to each function. By integrating small inertia linear engine and pump piston in one unit, the hydraulic free piston engine is an efficient and fast response hydraulic power source. Since the hydraulic free piston engine is essentially a digital hydraulic power source, a digital load-sensing control is proposed in this study. The system architecture, modeling, controller design and performance of the digital hydraulic load-sensing control system are presented. A test bench is developed to verify the system feasibility and performance.

User-focused evaluation of National Ecological Observatory Network streamflow estimates

Accurately estimating stream discharge is crucial for many ecological, biogeochemical, and hydrologic analyses. As of September 2022, The National Ecological Observatory Network (NEON) provided up to 5 years of continuous discharge estimates at 28 streams across the United States. NEON created rating curves at each site in a Bayesian framework, parameterized using hydraulic controls and manual measurements of discharge. Here we evaluate the reliability of these discharge estimates with three approaches. We (1) compared predicted to observed discharge, (2) compared predicted to observed stage, and (3) calculated the proportion of discharge estimates extrapolated beyond field measurements. We considered 1,523 site-months of continuous streamflow predictions published by NEON. Of these, 39% met our highest quality criteria, 11% fell into an intermediate classification, and 50% of site-months were classified as unreliable. We provided diagnostic metrics and categorical evaluations of continuous discharge and stage estimates by month for each site, enabling users to rapidly query for suitable NEON data.

Research on PID Controller of Excavator Electro-Hydraulic System Based on Improved Differential Evolution

An electrical hydraulic control system (electro-hydraulic system) is thought to be a key component in excavator operation systems. Control methods with fixed parameters may not yield optimal system performances because a hydraulic system has various nonlinear uncertainties due to the leakage and compressibility of the fluid medium. Hence, a novel PID controller based on improved differential evolution (IDE) is introduced to excavator electro-hydraulic systems for interconnected hydraulic systems. The proposed algorithm not only adjusts the PID parameters of the different working conditions but also adjusts the scaling factor and crossover probability. Then, the proposed PID controller based on IDE and the excavator bucket control system are modeled and simulated on the MATLAB simulation platform. The simulation results demonstrate that the proposed controller has better performance in settling time, rise time, and convergence speed compared to the PID controller based on standard differential evolution and the Ziegler–Nichols (ZN) PID controller with a novel object function. Eventually, the IDE-PID controller is assessed on a 23-ton excavator, and good transient behavior and trajectory accuracy are obtained in comparison to the SDE-PID controller.

Plant hydraulic resistance controls transpiration of soybean in rotational paddy fields under humid climates

Efficient irrigation and drainage management are highly required for increasing crop productivity in paddy rice and upland crop rotation. However, conventional management does not sufficiently consider the water status of the plants and soil in the root zone. The aim of this study was to evaluate whether the hydraulic resistance of soil (Rs) or plant (Rp) principally controlled transpiration in rotational paddy fields (RPFs) located in humid regions. To achieve this, we conducted field measurements of soil water conditions, evapotranspiration rate, and leaf water potential in RPFs cropped with soybean after the flowering stage and calculated Rs and Rp based on the theory of root water uptake. After the flowering stage, the soil was sometimes saturated owing to intermittent precipitation, and thus Rs was maintained at a low value. By contrast, Rp gradually increased over time and ranged between 5.1 × 108 and 10.3 × 108 s, which was one to three orders of magnitude higher than Rs. The ratio of the actual to the potential transpiration rate decreased throughout the investigation period and hardly reached 1.0, even though the soil was sufficiently wet. These results indicate that Rp, which probably increases with continuous soil saturation, controls crop transpiration in RPFs under humid climates. Our results suggest that drainage systems are essential in RPFs to avoid a change in Rp and improve crop productivity.

Theoretical research and maintenance of electro hydraulically controlled injectors

Introduction. Nowadays the part of the diesel engines for KamAZ-740 cars are operated with fuel equipment, in which the injectors have hydro mechanical control. Their main disadvantage is the low fuel pressure in front of the injector openings (less than 60 MPa) and the lack of fuel supply control.The use of injectors with electro hydraulic control (EHC) increases the pressure in the injector cavity up to 250 MPa and control the fuel injection process. The disadvantage of the injectors with EHC is a structural complexity of a control valve, the difficulty of its regulation and coding. The object of the study is the injectors of KamAZ-740 diesel engine with electro hydraulic control of the atomizer needle stroke.The purpose of this work is to carry out theoretical research and improve the methods of maintenance of injectors with electro hydraulic control (control valve regulation and coding), which will increase their reliability, durability and ensure a reduction in diesel fuel consumption.Research methods. The study of the nozzle control valve is theoretical and calculated. The paper proposes a calculation method and performs theoretical studies for the influence of pressure (50 – 250 MPa) on the value of the effective flow section and the diameter of the nozzle holes of the sprayer.For the injectors with EHC, the control valve regulation procedure has been clarified, which consists in the fact that at the beginning of regulation, the main force acting on the ball from the side of the maximum pressure in the control chamber (for example, 200 MPa) equal to 76 N is calculated (see Figure 4). Then the required spring force of 100 N is determined (20-40% more, see Figure 5). Next, the strength of the electromagnet is estimated at 140 N (20 – 40% more of the spring force, see Figure 6).The results of theoretical research. The results of computational (theoretical) studies for the effective flow section of the sprayer and the diameter of the nozzle holes, depending on the pressure P in front of the nozzle holes, are presented.The paper defines. 1. The forces acting on the ball (57 – 105 N) depending on the pressure in the control chamber (150 – 275 MPa). 2. Spring forces (40 – 140 N) with a stiffness of 40 N /mm, depending on its compression up to 3.5 mm. 3. The forces of the electromagnet (140 – 20 N) depending on the gap between the anchor and the core (0.2 – 0.5 mm).The method of restoring the required (rated) cyclic fuel supply when it changes as a result of replacing the control valve or adjusting is considered. The calculated values of fuel supply per cycle (mm3/cycle) from the activation time are given.Conclusion. The results of the study are intended for organizations and enterprises engaged in diagnostics, restoration, adjustment and coding of injectors with electro hydraulic control for the needle stroke of sprayers. The results of computational studies can be used to refine the methodology of maintenance of fuel systems with electronic control (Common Rail).

СОВЕРШЕНСТВОВАНИЕ НОРМАТИВНО-ПРАВОВОГО ОБЕСПЕЧЕНИЯ ПРИМЕНЕНИЯ ГИДРАВЛИЧЕСКИХ ПОДЪЕМНИКОВ НА ПОДКРОВЕЛЬНОМ (ПОДВЕСНОМ) МОНОРЕЛЬСОВОМ ТРАНСПОРТЕ

In this article, the authors consider some regulatory legal acts concerning monorail transport and the calculation of anchor support for underground monorail cargo trucks (lifting technical devices with hydraulic control from a diesel-hydraulic locomotive) with attachments used in mines. Evaluation of the effect of a regulatory legal act is an important stage, the essence of which is to obtain and analyze information concerning the impact of a regulatory legal act on social, industrial relations, which, in turn, allows improving the current legislation, as well as taking into account the role of legal practice in the development of new regulatory legal acts. A huge role is played by the prevention, detection and elimination of defects in regulatory legal acts. Identification of defects in regulatory legal acts is carried out after the entry into force of a regulatory legal act by evaluating the results of its action. Elimination of defects in a regulatory legal act is carried out within the framework of additional law-making, aimed at eliminating the identified defect of a regulatory legal act, is a unified system of actions and procedures that allow to establish the presence of a defect, the cause of its occurrence, and, taking into account the information received, make appropriate changes to the legislation. In regulatory legal acts, the term «hydraulic lift» is not used, lifting devices with hydraulic control from a diesel-hydraulic locomotive operating (moving) along a monorail beam in a mine. There is a need and the possibility of finalizing regulatory legal acts concerning the solution of tasks related to the organization of the technological scheme of hydraulic lifts with cargo, that is, slinging, lifting cargo and moving cargo by hydraulic lifts in the mine, in underground mining conditions. Understanding that the laws of slinging, mechanics and physics concerning the process of lifting and moving loads both on the surface, for all kinds of lifting devices, structures, and in underground conditions, work the same way, and in the legal field is not specifically defined.

PRECLASSIC MAYA FORTIFICATION AT MURALLA DE LEÓN, PETEN: DEDUCING ASSETS, MILITARY STRATEGIES, AND SPECIFIC THREATS THROUGH ANALYSIS OF DEFENSIVE SYSTEMS

AbstractIn the absence of historical records, ethnography, or artistic depictions, fortifications provide one of the best forms of evidence for insight into the nature of warfare within past societies. Excavations into the monumental stone perimeter wall, 1.5 km in circumference, at Muralla de León in the Peten Lakes Region have dated its initial construction to the first two centuries of the Late Preclassic period (400–200b.c.). Investigation into this apparent fortification offers new insight into Maya settlement and monumental construction in relation to warfare in this era, as sociopolitical complexity became increasingly widespread across the southern lowlands. Calculations of affordances of movement across the local landscape using geographic information systems and Circuitscape inform a spatial statistical analysis of fortification at Muralla de León, performed to test a hypothesis of defensive functionality for the encircling perimeter wall. A separate affordance of movement analysis at a regional scale locates the site within probable intersite paths of travel. The research indicates a significant, but not exclusive, defensive intent underpinning the Preclassic form of the main wall system. Thus, the system was built in part as a fortification, restricting movement toward the interior, while facilitating other uses such as hydraulic control and possibly trade.

Structure design and performance analysis of downhole hydraulic decoder

In order to reduce the number of hydraulic decoders and hydraulic control pipelines in hydraulically controlled intelligent wells, reduce production costs and improve oil recovery efficiency, the structural design of ICV control of two hydraulic control pipelines and a single hydraulic decoder for four production layers in the well was completed. By simulating the response law of downhole hydraulic signals and the stress analysis of each structure, the motion equation of the layer selection structure of the hydraulic decoder was established with 4 MPa as the unlocking pressure, and ADAMS was used to complete the dynamic simulation analysis. The variation results of displacement, angle, velocity and acceleration in the process of motion were obtained. Finally, the prototype of the hydraulic decoder was processed by stereo photo curing 3D printing equipment. Two hydraulic pumps were used to press alternately, and the selection of four layers of the hydraulic decoder was realized through two hydraulic control pipelines. The self-locking structure could realize the established function, and there was no interference and stuck between the components, which verifies the effectiveness of the design.

БИОЛОГИЧЕСКИЕ МЕТОДЫ ОЧИСТКИ ОКРУЖАЮЩЕЙ СРЕДЫ ОТ ТЯЖЕЛЫХ МЕТАЛЛОВ

The entry into the environment of various pollutants associated with anthropogenic activities adversely affects its condition. Heavy metals make a significant contribution to the deterioration of the environmental situation, which requires the adoption of certain measures to minimize it. The role of living objects (microorganisms, plants, fungi, algae) in the biotransformation of these xenobiotics into non-toxic forms is well studied and is a developing area of biotechnology. It offers efficient, cost-effective and environmentally friendly approaches to clean up soils and aquatic ecosystems contaminated with metals. This literature review analyzes phytoremediation mechanisms, including phytoextraction, rhizofiltration, phytostabilization, phytovolatilization, phytodegradation, rhizodegradation, and hydraulic control, as well as various strategies of bacteria, algae, fungi, such as bioaccumulation, biosorption, biotransformation, biomineralization. The advantages of using certain mechanisms, their limitations and prospects are compared.

Fully hydraulic synchronous steering control of vehicle based on gain fuzzy sliding mode variable structure

Fully hydraulic synchronous steering control of vehicle based on gain fuzzy sliding mode variable structure

Waste heat recovery and reuse for ship hydraulic oil temperature control system

In order to solve the problems of high energy consumption and serious waste of heat energy in the traditional oil cooler of Marine hydraulic system, the waste heat recovery and reuse of Marine hydraulic oil temperature control system is proposed. The hydraulic system waste heat recovery test platform has been established, the influence of electrical load, oil flow rate and working medium flow rate on system operation and energy characteristics is studied. The experimental results show that under the same working condition, compared with the oil cooler of the same specification, the maximum thermal efficiency of the proposed organic Rankine cycle waste heat recovery system is increased to 2.56%. The expander pressure ratio and system thermal efficiency increase with the increase of electric load and oil flow. The experimental results analyzed the energy saving effect of waste heat recovery system on hydraulic system, and obtained the rule of system operation efficiency.

Fully hydraulic synchronous steering control of vehicle based on gain fuzzy sliding mode variable structure

Fully hydraulic synchronous steering control of vehicle based on gain fuzzy sliding mode variable structure

虚拟仿真技术在液压控制系统课程中的应用研究

虚拟仿真技术在液压控制系统课程中的应用研究

Sliding Mode Control of Digital Directional Valve Drive System Based on New Approach Rate

As an important development direction of hydraulic control components, static and dynamic properties of the spool drive mechanism determine the dynamic and static performance of the digital valve. For the study, permanent magnet synchronous motor and screw nut unit are used as the core drive mechanism for digital directional valve. To solve the practical problems that permanent magnet synchronous motor can not meet the performance requirements of digital directional valve in terms of spool position control accuracy and response speed, a sliding mode variable structure control algorithm with improved approach rate is registered, then the controller is devised and applied to position high-performance control of spool drive mechanism of digital directional valve. The simulation platform of digital directional valve drive system is built by MATLAB/Simulink software and compared with the control effect of traditional PI control algorithm. The emulation results show that can improved approach rate sliding-mode controller can be good for raise the speed of response and reinforce the trueness of the dynamic tracking accuracy of the system, has good dynamic response characteristics, and satisfies the performance requirements of digital directional valve.

Nonlinear Dynamics of Pilot-Operated Hydraulic Control Valves for Submersible Based on Improved Newmark- Integration Method

Nonlinear Dynamics of Pilot-Operated Hydraulic Control Valves for Submersible Based on Improved Newmark- Integration Method<i />

Design and implementation of a nonlinear robust controller based on the disturbance observer for the active spray boom suspension

Spray boom vibrations are one of the main causes of the uneven distribution of agrochemicals. Using active suspension to maintain the correct height of nozzles is critical for obtaining a uniform spray pattern and minimizing the possibility of spray drift. However, the electro-hydraulic active pendulum boom suspension has nonlinear uncertain factors such as parameter uncertainties, external disturbances, model error, etc., which complicate the design of the controller. Therefore, this paper proposes a nonlinear robust feedback control method with disturbances compensation, which integrates a robust controller and disturbance observers through the backstepping method. Initially, to verify the performance of the controller, the Lyapunov stability theory is used to prove that the proposed controller can guarantee the given transient performance and the final tracking accuracy. Furthermore, taking the active suspension of a 28 m wide boom driven by a single-rod hydraulic actuator as an implementation case, the proposed NRCDC controller was compared with a variety of control schemes through a rapid control prototype of a pendulum active suspension. Finally, the proposed control scheme is implemented on a self-propelled sprayer with a boom of 12 m in length. The field test results show that all the performance indicators of the NRCDC controller are better than the other three conventional controllers. Both laboratory and field tests have verified the effectiveness and high performance of the proposed controller. Keywords: robust control, sprayer boom, boom suspension, hydraulic control system, disturbance observer DOI: 10.25165/j.ijabe.20231601.7007 Citation: Cui L F, Xue X Y, Kong W, Ding S M, Gu W, Le F X. Design and implementation of a nonlinear robust controller based on the disturbance observer for the active spray boom suspension. Int J Agric & Biol Eng, 2023; 16(1): 153–161.

Simulation Analysis of Hydraulic Control System of Engineering Robot Arm Based on ADAMS

Simulation Analysis of Hydraulic Control System of Engineering Robot Arm Based on ADAMS

Investigation of thermal behavior and orifice flow characteristics of aeronautic hydraulic servo-proportional valve spool-sleeve structure with numerical simulations

In this study, the mechanical behavior under highest thermal conditions and flow characteristics of the hydraulic fluid of the servo-characterized proportional valve, which is one of the indispensable components of the aviation industry and used for hydraulic flow control, were investigated numerically. In the simulations, 50, 75 and 100 °C were selected as temperatures, and 0.2 mm, 0.6 mm and 1.2 mm spool stroke openings were used for hydrodynamic flow. Simulations were carried out for a pressure difference of 35 bar. As a result of the analysis, it was observed that there was no restriction in the movement of the spool-sleeve structure for a temperature of 75°C, excessive friction occurred in the spool-sleeve structure at 100°C and the movement was restricted. In addition, it can be said that hydraulic turbulences are effective in dispersing polluting particulate matter for all three spool strokes at a pressure difference of 35 bar.

小型多功能农用底盘液压驱动系统的设计与试验

In view of the problems of the output power and operation, when the multi-function machine in hilly and mountainous areas driving in the field, the hydraulic control drive system of small multi-function agricultural hydraulic chassis is designed. The key components of the hydraulic drive system were selected and matched. The hydraulic system simulation model was established in AMESim simulation analysis software, and the dynamic analysis of the hydraulic system operation under different conditions is carried out. The simulation analysis results show that the hydraulic system has a large impact and vibration when it is started instantaneously, and the hydraulic system has smaller impact and vibration when it is started stably. It is consistent with the actual working state of the hydraulic chassis. Under the two starting controls, the maximum flow of the hydraulic pump is 50L/min, the motor torque is about 440N • m, and the motor stable pressure is 6Mpa, the motor speed is 96 r/min, which is within the bearing range of the hydraulic components. The simulation output parameters are basically consistent with the theoretical calculation results, and meeting the design requirements. The chassis performance test results show that the maximum crossing height of the chassis is 200mm, the crossing width is 300mm, the maximum deviation of high-speed straight driving is 2.57m, it can stably pass 20° slope, and the operation is stable and the steering is flexible. All performance parameters can better meet the requirements of chassis operation in hilly and mountainous areas.

Modelling and Experimental Verification of the Interaction in a Hydraulic Directional Control Valve Spool Pair

This study examined the impact of mechanical oscillation on a hydraulic directional control valve. Particular attention was paid to the oscillating movement of the spool of the hydraulic directional control valve resulting from this impact. Different models of fluid and mixed friction were considered. The models analysed accounted for the relative movement of the directional control valve body and the fact that it is kinematically excited by external mechanical oscillations. It was observed that the mixed friction model, where the frictional force is considered to be the sum of molecular forces acting in micro-areas of contact and drag forces in the fluid, was the best for describing the movement of the spool for a specific spool oscillation frequency. This model yielded significantly more consistency between the simulated and experimental results than the classic fluid friction model.