通过对大型混合机液压系统原理的介绍,表明了该液压系统的优势;通过对其常见故障进行的分析,对减少和避免系统故障停机有重要意义,有助于系统更好、更稳定的运行。

Soft robot is a novel category of robotics made of soft materials, which has the characteristics of small stiffness and high flexibility. The movement performance and application range of soft robots are mainly affected by the driving modes. The driving modes are summarized as fluidic driving, tendon driving, shape memory alloy driving, electro-active polymer driving and hybrid mode. The fluid driving has been widely used because of its diverse forms, fast response speed and high carrying capacity. According to the different structure forms of fluid driving, the fluid driving in soft robotics can be divided into pneumatic driving, hydraulic driving and micro-fluid driving. At the same time, pneumatic actuation are divided into fiber braided type, spiral type, mesh type, origami type and special type by their structural forms. By reviewing and analyzing and analyze the fabricating method, the main problem and the following trends on the fluid driving of soft robots are proposed.

For the hydraulic system of the large-diameter mud-water shield machine, combined with the large-diameter mud-water shield machine used in the Wuhu Yangtze River Tunnel Project carried out by China Railway 14th Bureau Group Large Shield Engineering Co., Ltd., This paper focuses on the working principle and main structure of the shield machine, the working principle and main components of the shield machine hydraulic system, and summarizes the research progress of the shield machine hydraulic system fault types and fault diagnosis related technologies, and summarizes the current shield machine hydraulic system. The development status of related technologies of the system has pointed out the direction for related research in the field of shield tunneling machines. It is hoped that it can provide assistance to the technical personnel in related industries in my country to deeply study the composition structure and fault diagnosis of the hydraulic system of shield tunneling machines, and promote the technological progress of the industry.

Aiming at the problems of the existing isothermal discharge method, such as big measurement error and poor repeatability, a deep research on the measurement errors of the isothermal discharge method has been conduced. The influences of the pressure gradient, the temperture gradient and the measurement noise on the results of the isothermal discharge method have been discussed, the research products are helpful for improving the performance of the isothermal chamber and reduce the measurement error of the isothermal discharge method for testing the flowrate characteristics of the pneumatic components.

气动机械手是一个由机械、气动、电气、PLC 和触摸屏等元件构成的复杂的机电一体化工业装备,机械动作复杂且具有严格的先后逻辑关系。该文基于PLC 和触摸屏设计的气动机械手控制系统,既保证了机械手各种动作之间的严格先后逻辑关系,也实现了操作过程的可视化和系统的安全性。机械手在实际运行过程中,动作顺畅、性能稳定、可靠性高。

我国工程机械行业规模总量已跃居世界首位,成为国民经济发展的重要支柱产业之一。装载机和挖掘机产量均为世界第一,随着年产量和保有量的不断增加,工程机械已成为继汽车之后的又一燃油消耗主体,能量利用率已成为评价工程机械产品市场竞争力的重要指标。针对影响工程机械能量利用效率的主要因素,从提高元器件效率、降低液压系统能耗、动势能的回收再利用、动力匹配和混合动力技术方面,介绍了降低工程机械能耗的主要技术进展和新的研究成果。希望能对我国相关行业技术人员开发新的节能产品,探索、研究新的节能理论和方法,开发新型节能元件提供有益的启发,推动行业技术进步。

China is the largest energy consumer in the world. Environmental problems, crude oil import and shortage crisis have become a heavy burden for Chinas sustainable development. Construction machinery is one of the most important role in China. Improving the energy efficiency of construction machinery is an effective way to meet the energy demand of national economic development and to cope with environmental problems. In view of the fact that many work devices of construction machinery can feed back energy to the system, it is presented the main technical progress and new research results of energy saving and consumption reduction for high frequency operation mechanism with large mass and moment of inertia. It is hoped that the principle and method of energy recovery can promote the development of industry and technological progress, so as to improve the quality and level of construction machinery in China.

实验室建设是高校专业建设和课程建设的重要组成部分。该文就《流体传动与控制》实验室的建设,从流体传动与控制实践教学存在的问题、校企合作共建实验室的思路与原则、共建实验室的主要内容等方面进行了阐述。

The piston-cylinder interface, as a key friction pair in an axial piston pump, directly affects its reliability and service life. This paper establishes the Reynolds equation and force equation for the piston-cylinder interface, and solves them using discretization in MATLAB. A comparative analysis of the minimum film thickness, film pressure, friction, and leakage between the drum-shaped and conventional piston-cylinder interfaces under the same conditions is conducted. The results show that, compared to the conventional piston-cylinder interface, the drum-shaped piston-cylinder interface has a larger minimum film thickness, improving lubrication performance. It also exhibits distinct pressure peaks, with more significant squeezing effects on the film. The drum-shaped piston reduces axial and circumferential viscous friction, enhancing fluid flow efficiency, but increases leakage during motion, reducing sealing performance. These findings provide a theoretical basis for improving the lubrication performance of the piston-cylinder interface.

The air suspension system has the advantages of long service life, low self-vibration frequency, adjustable stiffness and height, and is widely used in field vehicles. However, the existing suspension system has problems such as single control mode, difficult parameter decoupling, nonlinearity and serious time delay, which directly limits the improvement of vehicle safety, comfort and passability. This paper analyzes the current research situation in vehicle air suspension system, suspension system parameter modeling and air suspension control technology at home and abroad, and points out the existing problems and future development trends in automobile air suspension system and precision control technology in China, which provides a reference for the development of high-precision control technology of air suspension in China.

Hydraulic simulation technology has become an important tool for the design and analysis of hydraulic system. As one of the hydraulic simulation softwares, the AMESim software with its own advantages has been accepted and applied in the construction machinery and the hydraulic industry. Combined with the actual cases, the applications of AMESim software in system optimization design, component series development, dynamic power flow simulation analysis, cosimulation and so on are exampled in this paper.

As a new type of bionic robot, soft robots have broad application prospects with outstanding advantages such as strong environmental adaptability, flexible mobility and soft body in the fields of space exploration, disaster rescue, medical health and so on. Soft robots are mainly composed of soft body materials and smart actuating/sensing materials. Focusing on the actuating technology of soft robots, firstly, the fluid actuating mode based on gas/liquid fluid elastomer material is introduced and summarized. Then, the mixed fluids actuating technology is introduced. Subsequently, the development and application of electro-hydraulic actuating technology in soft robot field has been highlighted. Finally, the electrical/magnetic/optical/thermal actuating technologies and corresponding typical applications are analyzed and discussed. Meanwhile, the difficulties and opportunities for the future development of soft robot are discusseed in detail.

With the continuous development of oil drilling, drilling construction is increasingly difficult, it is difficult to meet the needs of underground oil drilling intensity and efficiency. Based on the extensive research on the petroleum equipment data at home and abroad, the hydraulic system of drill, blowout preventer, oil drain and tubing tractor in the key equipment of oil drilling rig is introduced in detail. In order to promote the improvement of the technical level of the key equipments in the domestic oil drilling system, based on the analysis of the main features of the hydraulic system in the key equipment of underground oil drilling and its composition and function, The status of the application of the hydraulic system at home and abroad on the oil drilling rig is reviewed. Combined with the research progress at home and abroad, the author puts forward the suggestion that the hydraulic system in the key equipment of underground oil drilling should develop in the direction of high reliability, high labor intensity, high work efficiency and low failure rate.

Aiming at the current problems of the hydraulically actuated quadruped robot, such as chaotic structure, large energy loss and complex control strategy, the research status of quadruped robot is analyzed from the robot, hydraulic system and control strategy. Firstly, the robot of each team is introduced, and the technological gap between China and developed countries is pointed out. Then, the main two components of the hydraulic system are described from four aspects: power source, system types, hydraulic circuit and servo actuator, during which the energy saving system and highly integrated servo actuator are introduced in details. Then several mainstream control strategies are summarized, and their respective advantages and disadvantages are pointed out. Finally, the future trends of hydraulically actuated quadruped robot will concentrate on high speed, high pressure, lightweight, energy-saving system, noise reduction and advanced control algorithm, so as to realize the high dynamic performance and industrial application.

变量马达经常组成容积调速回路应用于液压系统的开式和闭式回路中。其主要优点是功率损失小(没有溢流损失和节流损失),且其工作压力随负载变化,所以效率高、油的温度低,特别适用于高速、大功率系统。该文介绍了几种轴向柱塞式液压马达的变量原理,目的是使从事液压专业的工程技术人员能够正确使用、调试和维护液压变量马达。

Electro-hydraulic servo system is widely used in aerospace, aviation, ships, weapons, metallurgy, machine tools, simulation test and other fields because of its distinct advantages such as strong load capacity, high power-to-weight ratios, quick response and high control precision. In this paper, in terms of electro-hydraulic servo valves, systems and practical application, the status and development of the electro-hydraulic servo techniques are generally elaborated.

阐述液压型风力发电机组主传动控制系统国内外发展现状。介绍液压型风力发电机组主传动系统的组成、功能与运行特性,阐述液压型风力发电机组主传动控制系统的工作原理。归纳液压型风力发电机组主传动控制系统关键技术。总结液压型风力发电机组主传动控制系统的优势。

Flow pulsation is an inherent property of the delivery oil of axial piston pumps. The pressure pulsation induced by flow pulsation affects the working quality and service life of axial piston pumps and even the entire hydraulic system. To clarify the causes and components of flow pulsation, a three-dimensional transient CFD model of an axial piston pump is established, a test platform for pressure pulsation at the outlet of an axial piston pump is built to verify the numerical model experimentally. In addition, the pressure pulsation components due to geometric pulsation, backflow pulsation, leakage pulsation and dead zone pulsation are obtained by adjusting the geometrical structure parameters of the simulation model. The verified simulation model is employed to analyze the amplitude contributions of each flow pulsation component under different operating conditions. The simulation results indicate that geometric pulsation and backflow pulsation have positive contributions to the flow pulsation, while leakage pulsation and dead zone pulsation have negative contributions to the flow pulsation. The geometric pulsation, backflow pulsation, dead zone pulsation,and leakage pulsation account for 9%, 214%, -35% and -88%, respectively, of the total delivery flow pulsation at a discharge pressure of 10 MPa and a rotational speed of 1000 r/min. The research results provide an important theoretical basis for the formation mechanism and suppression methods of the delivery flow pulsation in axial piston pumps.

Buoyancy adjustment system is an important part of deep-sea vehicles to compensatebuoyancy changes and adjust the attitude of the vehicles. Based on the buoyancy adjustment application of a new 6000-meter remotely operated vehicle, a deep-sea oil bladder type buoyancy adjustment system has been developed. The system components, working principle and key components design are introduced in detail. Strength analysis, stability check and the pressure testing under simulated deep-sea environment are conducted. The results show that the system can discharge 60 MPa high-pressure oil to the bladder and the oil tank can withstand 66 MPa pressure. The two trials show that the system can realize buoyancy adjustment in 6000 m deep-sea. In addition, the attitude adjusting experiment is conducted in water tank, which validates the effectiveness and feasibility of the system.

In coal mining, a pneumatic monorail crane is flexible and no explosion-proof problem, and it is widely used. The design of drive part of pneumatic monorail is studied, and the design of the main components and the design of pneumatic system are carried out. We use the software FluidSIM to model and simulate the pneumatic system, and the rotation speed curve of pneumatic motor and the piston displacement curve of brake cylinder are obtained, and the relation curve between trajectory slope and load is obtained by MATLAB software programming. According to operation principle of driving part, we analyze the curves obtained, and verify that the design can achieve the desired action, and the system responds quickly, and its pressure is stable during operation, and it meets the technical requirements of drive department.

风力发电是可再生能源领域中最成熟、最具规模开发条件和商业化发展前景的发电方式之一,具有广阔的应用前景。液压技术由于可以达到大功率输出、可靠的控制精度、所占空间少等要求,在风电行业中得到广泛的应用。该文从风电机组液压制动系统、定/变桨距功率液压控制系统以及液压主传动系统三个方面介绍了液压技术在风力发电中的应用,并通过理论分析和原理图进行详细的说明。分析表明,在风力发电中应用液压技术可以提高系统稳定性,减小风速波动对系统部件的冲击,提高风力发电的效率。

The 11th National Conference on Fluid Power Transmission and Control, sponsored by Fluid Power Transmission and Control Institution CMES and hosted by Shanghai Jiaotong University, was successfully held in Shanghai from October 31 to November 2, 2020. The theme of conference is “Fluid Power Transmission and Control+Artificial Intelligence”. A total of 133 papers covering six topics, including artificial intelligence and digitization, components and systems, sealing, friction and lubrication, were accepted by the conference, and 9 well-known experts, such as Yang Huayong, Jiao Zongxia, were invited to give reports on Fluid Power Transmission and Control. The conference theme, topics, reports and papers are summarized, and the relevant statistical data are analyzed and discussed, so as to provide reference for domestic scholars and engineers.

Taking a certain type of dual-chamber controlled hydraulic rock drill as the research object, this study aims to minimize the clearance energy losses between the impact piston and the cylinder. The lumped parameter modeling method is adopted to establish the mechanical models of the impact system, the damper system, the rock and the piston and cylinder clearance energy consumption model on the basis of considering the compressibility of the oil, the pipeline pressure losses and the leakage, and the corresponding AMESim graphical solving model is constructed. Under specified structural parameters, the motion curves of the piston and the spool valve, the transient process of the controlled chamber pressure and the characteristics of the clearance energy losses are calculated. The impact mechanism of size on clearance energy consumption is analyzed. The relationship of the piston-cylinder clearance and the working pressure are summarized when the energy loss of the gap is the smallest. It can provide a theoretical basis for the determination of the radial fit gap between the piston and the cylinder of a hydraulic rock drill.

Air springs have significant application prospects in quasi zero stiffness system, and their stiffness characteristics are the key to analyzing their performance. A single-convolution bellows type air spring is studied as the research object, and its static and dynamic characteristics are systematically investigated through a combination of theoretical analysis, numerical simulation, and experimental research. A stiffness calculation model for the single-convolution bellows type air spring is established based on gas dynamics theory, and expressions for vertical stiffness and natural frequency are derived. A finite element model of the G40/60 type air spring is constructed by ABAQUS software, and the influence of initial internal pressure on stiffness characteristics is analyzed. Static tests are conducted on a WDW-100 testing machine, where force-displacement characteristic curves under different air pressures are obtained. Load-bearing capacity and static stiffness expressions are derived through polynomial fitting. Dynamic tests are performed on an MTS 831 testing machine, and the effects of air pressure, frequency, and amplitude on stiffness and damping characteristics are studied. Theoretical foundations and design bases are provided for the application of air springs in quasi zero stiffness system.

The direct drive motor-pump has become one of research focuses in the hydraulic system research for its advantages of simple structure, small size, high efficiency, low noise etc. In this paper, we discuss the disadvantages and advantages of the valve regulation and pump-controlled hydraulic system, and introduce the fundamental of the direct drive motor-pump derived from the integration of an electric motor and a pump. Focusing on the basic structure, working principle and characteristics of the direct drive motor-pump, we discuss its key technology and development trend.

As one of the important means to ensure the quality and safety of the product, the air tightness of industrial equipment is required to be higher and higher. For the three aspects of leakage detection, leakage judgment, leak localization and leakage ratedetermination, this paper describes the history and development of domestic and international gas leak detection methods, and explains the technology of ultrasonic and infrared detections which rise in recent years in detail.

A timing charging and discharging system of pneumatic or hydraulic pressure device based on STM32 is designed, which mainly opens or closes the solenoid valve in the pipeline. FATFS file system, UCOSIII OS and emWin graphic design system are transplanted into STM32. The data of system settings are saved in W25Q64. The interface operation and display are carried out by resistive touch screen and LCD. Six interfaces including system desktop, screen calibration, monitor, system setting, manual operation and about the system are designed and manufactured. Two kinds of timing logic are designed by timing function and global variable of timing count, which can select two timing modes of high pressure and low pressure. In manual operation mode, the system closes the charging valve and performs exhaust timing only. The results show that the device can be used accurately in many kinds of pneumatic or hydraulic pressure charging and discharging tasks.

Electro-hydraulic servo system is widely used in aerospace, aviation, ships, weapons, metallurgy, machine tools, simulation test and other fields because of its distinct advantages such as strong load capacity, high power-to-weight ratios, quick response and high control precision. In this paper, in terms of electro-hydraulic servo valves, systems and practical application, the status and development of the electro-hydraulic servo techniques are generally elaborated.

Porous graphite materials significantly influence the performance of porous restrictors, which are key components of aerostatic guideways. This study employs the compressible Darcy-Forchheimer equation to fit experimental data and determine the permeability and inertia coefficients of porous graphite with five different porosities (18%, 17%, 13%, 12%, 11%). A CFD model incorporating these coefficients is established, accurately predicting the flow velocity and pressure drop within the porous medium, with an error margin within 5%. Further analysis under various supply pressures and loading conditions reveals that restrictors made from low-permeability graphite materials exhibit superior load-bearing capacity and gas film stiffness. Specifically, under a supply pressure of 0.45 MPa, the stability of the aerostatic block is significantly enhanced. Based on this research, an experimental platform for an aerostatic guideway with an adjustable gas film thickness is constructed using low-permeability restrictors. The guideway surface straightness is verified using a Keyence laser sensor, achieving better than 2.5 μm/600 mm.

Researches on the principles, performances and efficiency of the fresh water collector have a very significant meaning for outdoor activities and field work. Energy exchange and utilization must be considered while designing a water-from-air system because of the phase changing processes during converting the water vapor into drinkable liquid water. We design a portable microfluidic atmospheric water-generator by utilizing the microfluidic technology and adsorption-desorption principle to reduce the volume and energy consumption of the microfluidic atmospheric water-generator, improve the efficiency of fresh water collection.

工程机械多路阀是工程机械液压系统中的重要控制元件,决定了工程机械的操控性能。该研究对工程机械最新发展现状进行了分析概述。重点分析了负载敏感技术、负载独立流量分配技术和双负载口独立控制技术等在多路阀中的应用,并对多路阀的发展趋势进行展望。

Ideological and political theory course is the key course to implement the fundamental task of building morality and cultivating people. The teaching of traditional prior knowledge has become a constraint on the development of new technology and thought to a certain extent. Fluid transmission and control technology is the core basic course of mechanical specialty. Multiple backgrounds such as world science and technology competition and the construction of China's scientific and technological power provide new opportunities and missions for the teaching of fluid transmission and control technology. This paper puts forward a new teaching model of “whole chain” of curriculum thought and politics with the teaching goal of building a powerful country in science and technology; Using the combination of explicit and implicit education methods; With the education system of full staff, whole process and all-round participation, the teaching concept of truth, goodness and beauty, knowledge, emotion, point, line and surface, competition, innovation and research is integrated; Excavate the ideological and political elements with accurate background, professional courses, charts, formulas and applications, which are closely combined, linked and driven forward like a wheel chain. Help cultivate high-tech professionals with “scientific and technological literacy, patriotism and professional knowledge”, and provide intellectual support for building a scientific and technological power.

In some engineering applications, accumulators are used for supplying oil for electro-hydraulic position control systems. Different from the traditional electro-hydraulic control systems, the supply pressure of the accumulators will decline over time, and the variable supply pressure will influence the control performance of systems. Aimed at the control problem of electro-hydraulic position systems based on the variable pressure oil source, an experiment platform is set up, and the mathematical model of the system is also built. In order to implement the dynamic compensation of this kind of electro-hydraulic position control system, the relationship between the supply pressure and the output flow rate of the accumulator, and the friction model based on the LuGre model are obtained by experimental methods. A compound compensation controller, which consists of one conventional PID controller, one feed-forward compensator (FFC), and one fuzzy controller (FC), is developed in this paper, and the trajectory tracking performance of the controller in the period intermittently operating electro-hydraulic systems is validated via comparative experimental results.

分析了工程机械,尤其是挖掘机液压系统中典型的变量柱塞泵、多路阀及变量液压系统的结构特点和工作原理,总结了近年来国内外工程机械关键液压元件及系统研发中的主要进展。结构简单化、高可靠性、节能、操作舒适是工程机械液压元件及其系统发展的主旋律,增强变量泵中控制阀的抗污染能力是提高变量泵工作可靠性的关键,复杂阀体铸造问题将促使整体式多路阀向分离式结构回归。

The stateoftheart of pneumatic vacuum technology in material handling is introduced in this paper. First, research on the performance improving and energy saving of the vacuum ejector is presented. Then, the research and developing advance on vacuum pads and the novel integrated vacuum pads such as coanda ejector, cyclone pad and Bernoulli pad are introduced. Moreover, the new advance on the vacuum confirming and isolating technology is also described. Thus, some trends on the development of the pneumatic vacuum technology in material handling are summarized.

This paper introduces the basic principle of high-pressure water jet technology, analysis the principle and characteristics of continuous jet and pulse jet, and summarizes the high pressure pure water jet and abrasive water jet with different characteristics, summarizes the principle and characteristics of two kinds of mixed mode of abrasive, and the high pressure water jet cutting technology as emerging applications in the field of rust and the.

The Chinese and foreign research on torque converter are summarized from three aspects including design, analysis of flow field and optimization. The development trend in future is also investigated primarily including flat design, design platform development and details research of flow field characteristics. Based on the current research achievements, it is noted that design, analysis and optimization are always researched synthetically. Finally, the new development trend on the integration of the three aspects is put forward and the key technologies are discussed.

In order to cope with the traditional hydraulic solenoid reversing valve can not supply power for a long time and oil is sensitive to temperature rise, a new three-steady solenoid reversing mechanism is designed with three-position four-way hydraulic reversing valve as the carrier. The rapid reversing property of the mechanism makes the valve port close quickly, resulting in hydraulic shock in the pipeline. Therefore, the magnetorheological damping technology was introduced, and the “shear-valve” magnetorheological damping device was connected in series along the axis of the spool to control the closing rate of the valve port to alleviate the adverse effects of hydraulic shock on the system. The simulation results of AMESim show that the reversing process of active control damping slows down with the increase of damping force, the peak value of pipeline hydraulic shock decreases and the oscillation time decreases. However, due to the short commutation time and limited response capacity of variable damping device, closed-loop control is not recommended.

We use ABAQUS fluid pressure penetration loading method to simulate the aircraft actuator VL seal ring, and not only can this method get convergent solution under high pressure (35 MPa) but can find the critical point of contact and separation automatically. The process of the simulation can be divided into two steps analysis that is interference assembly and fluid pressure loading. We obtained the stress and strain nephogram and lip contact area pressure distribution of the seal in different fluid pressure load respectively. Simulation results can provide related parameters for the theoretical calculation of the highpressure aircraft actuator seal,and provide related basis for practical application.

Selective Laser Melting (SLM), as one type of additive manufacturing technology, uses a laser to selectively melt metal powders in a layer-by-layer manner. The technique is able to process very complex structures and lightweight parts. On the basis of conventional manufacturing process, hydraulic passageways are suffered from excessive pressure loss, high weight, and large size. We design a servo valve manifold block with weight reduction of 37% based on the SLM technology. The simulation results show that pressure loss is reduced by 50%. Finally, we propose a SLM-based lightweight design of complex hydraulic passageways based on constraint analysis, model design, and simulation. The research shows the potential of applying additive manufacturing to manufacture hydraulic manifold blocks, which can achieve lightweight and improve flow characteristics.