One of the main problems of electrohydraulic drives is relatively low dynamic load stiffness due to compressibility of oil. Sudden load variations can cause significant deviations of the position of the drive and, consequently, a reduced precision of the controlled process. This has led to a partial substitution of electrohydraulic drives by electromechanical drives in a low power range recently.
One of the approaches to increase dynamic stiffness of a cylinder is to raise valve dynamics. Thus, the system can react to a control deviation and provide the cylinder with a compensating flow faster.
The objective of this paper is to show the development of a stiff cylinder drive using a new high-response servovalvethe hybrid valve. In contrast to a conventional servovalve with an unmovable sleeve, the idea of the hybrid valve is to actuate both the spool and the sleeve simultaneously in opposite directions. Using a piezo-actuator as sleeve drive provides the hybrid valve with very high dynamics in the range of small valve opening, which should be sufficient to increase the disturbance rejection of the cylinder. The performance of the valve prototype and of the cylinder will be shown, and application fields will be discussed in this work.

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This paper presents a new concept hydraulic valve that tries to overcome a well-known poser affecting the pilot operated proportional valves, the flow forces. Despite of the traditional compensated profile spool valves, the basic idea is to design a valve that has as few mobile surfaces as possible. This assumption modifies the traditional valve design method and opens to new possibilities for the proportional valves. The solution presented in this paper uses an axial fl ow valve, where the oil gets through the valve across its axis, with two rotating surfaces causing a rotational metering. The result of this new design approach shows several advantages with respect to the common spool valves, such as the extremely compact size and the device versatility. This particular valve can realize the majority of the functions achievable using a two-way two-position proportional valve piloted by two pressure signals (for example a pressure compensated valve); the axial flow and the “built-in” metering edges yield the possibility to produce this valve as a cartridge component, whit all the advantages incidental to this type of devices.
Some Computational Fluid Dynamics Analysis confirm the prediction of a low affection of this valve by flow forces, this attitude makes the axial Flow and Rotational Metering Valve particularly suitable for the local compensation in Flow Sharing Load Sensing distributors.

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The Stewart platform type parallel link mechanism with 6 degrees of freedom is a structure which has arranged six single rod hydraulic cylinders parallel between the base platform and the end effecter of the controlled object. The both ends of each link are connected with the base platform and the end effecter using free joints, respectively. The terminal can rotate freely. By controlling the length of each link by the hydraulic cylinder, the position and posture of the end effecter is controlled with 6 degrees of freedom in three-dimensional space.
In this report, the dynamic characteristics between the input and output of one link that comprises the parallel link mechanism is measured. The frequency response is measured for the various center position or attitude of the end effecter. The load mass and the amplitude are also changed.
The interference that each link receives from one link is examined by experiment. The frequency response of the interference that each link received is presented.

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A hydraulic lifting-moving-rail equipment test bench is designed, which can lift and move the rail for examining and repairing. The loading system is an electric-hydraulic servo control system. The original control strategy has some disadvantages, such as overshoot and slow response, which severely effect dynamic performance and test precision of system. According to the fuzzy control theory, the fuzzy-PID controller was designed by using ordinarily PID controller method. Experiments show that the performance of fuzzy-PID control system is obviously improved.

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Electro hydraulic actuator (EHA) system has inner and outer loops like a cascade system. The inner loop consists of an electric motor, a gear pump, and an angular velocity controller, and the outer loop consists of a hydro-actuator and a position controller. Especially, dead-band nonlinearity that exists between the electric motor and the gear pump and friction that occurs between the cylinder and the piston are considered. The tracking performance of EHA position control systems becomes unsatisfactory due to the dead-band and friction effects. Thus, in order to improve the position tracking performance of EHA systems with disturbance, backstepping control scheme for the desired position tracking is proposed, which is compared with the conventional PID scheme.

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An excavator consists of several hydraulic components which include pumps, a main control valve and cylinders etc. It operates by the linkage of the components. This paper is concerned with development of a hydraulic simulator for an excavator. The simulator has been developed using AMESim based on specifications of a 1.5 ton excavator. The excavator has been installed additional components to investigate an automated field robot; Electro proportional pressure reducing valve, electronic joysticks, angle sensors and a controller was installed at the excavator. The developed hydraulic simulator has the ability to represent with animation. The modeled MCV has been applied non-linear open area of spools.

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The paper introduces a novel system design of fluid power systems which improves the control and energy use for multiple actuators systems with particular focus on mobile applications such excavators, loaders, tractors. The system hereinafter described is based on a new patented technology [1], the “Load Sensing with Active Regeneration System”. The main idea is to overcome one of the main drawbacks of multiple actuators conventional Load Sensing Systems: while the higher actuator load drives the pump delivery pressure the other active actuators are controlled by the local compensators in a dissipative mode. The goal of the novel architecture is to actively use pressure drops usually wasted in the local compensators and, in case of assistive or overrunning loads, dissipated over control valves.

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Valve-less control is a new trend of electro-hydraulic servomechanism. It is possible to position the servo-cylinder directly by controlling the fluid volume discharged from an AC-servomotor drive pump. This paper discusses performance of this system on the point of preciseness, responsibility and stability. It shows efficiency of the system at low power.

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In the hydraulic servo control applications, hydraulic valve-controlled systems, which have a problem of low energy efficiency, are used mostly because of the high response characteristics. Hydraulic pump-controlled servo systems have high energy-efficiency. However, the conventional pump-controlled systems, which are altered by displacement via variable displacement pumps, have lower response. This paper aims to investigate the servo performance of the high response and high energy efficiency electro-hydraulic pump-controlled system driven by a variable rotational speed AC servo motor in comparison with the conventional pump-controlled systems which are altered by displacement via variable displacement pumps. For that, the control strategy, adaptive fuzzy sliding-mode controller (AFSMC) is introduced. The AFSMC can not only simplify the fuzzy rule base but also estimate the equivalent control force and online self-tune the rule base through the adaptive strategy. The developed high response variable rotational speed electro-hydraulic pump-controlled system controlled by AFSMC and the conventional variable displacement pump-controlled system (VDPCS) are implemented and verified experimentally for velocity control with various velocity targets and external loading conditions. Furthermore, the energy efficiencies of different experiments are analyzed and compared precisely by the power quality recorder used to measure the electrical power consumed by the AC servo motor.

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This paper deals with unsteady-state friction characteristics of a hydraulic actuator. Using a single rod hydraulic cylinder, friction characteristics are experimentally investigated under various conditions of velocity variation at different supply pressures. The friction force of the hydraulic cylinder is measured based on the equation of motion using measured values of the pressures in the cylinder chambers and the acceleration of the hydraulic piston. A method to identify dynamic parameters included in the modified LuGre model, which has been proposed by Yanada and Sekikawa, is proposed. Comparison between measured unsteady-state friction characteristics and those simulated by the modified LuGre model is conducted. It is shown that the unsteady-state friction characteristics simulated using the parameters identified agree with those obtained by experiments with a relatively good accuracy and that the proposed method to identify the dynamic parameters is appropriate. The effect of the supply pressure on the friction characteristics and the dynamic parameters are shown.

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The main source of vibration and noise in hydraulic systems is the flow ripple at the pump output which interacts with the downstream components and generates pressure ripple in the current, structureborne noise in mechanical parts and airborne noise in the environment. The present research was suggested by the observation that some peaks in the airborne noise spectrum of a specific pump family were within a frequency range far from those typically related with the fl uidborne or structureborne noise; unfortunately, in that range the human ear does not filter the noise efficiently.
In general, the investigation of the interaction between fluidborne noise and structurebornenoise can be carried through both “macro-analysis” techniques (sound emission analysis, pressure ripple measurement, modal analysis, etc.) and “micro-analysis” techniques (contact mechanics of gears, performance of the bearing system, etc.). The present research started from a “macro” approach inclusive of the modal analysis of a gear pump, the measurement of its pressure ripple and its acoustic mapping though the sound intensity technique. Currently, the focus is on the “micro” approach and specially on the investigation of the elasto-hydrodynamic bearing performance in view of deriving the influence of the bearing geometry on the overall structureborne noise.

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Noise is a well-known challenge in hydraulic systems and hydrostatic pumps are one of the largest noise contributors in a hydraulic system. The existing noise reduction features, such as pressure relief groove and pre-compression filter volume, are more or less dependent on the working condition. It is essential to know the amount of free air when designing a quiet pump; however, it is not evident how much free air the oil contains. The free air content is different if the suction port is boost pressured or self-priming. The amount of free air in a well-designed system can be as low as 0.5% while in others up to 10%.
This paper uses the three-transducer method to measure the amount of free air in the oil. The oil's compressibility can be measured for different working conditions and the free air content can then be calculated. The pre-study is performed with an extensive simulation model. Various noise reduction features' sensitivity to free air content is considered.

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Remote control of hydraulic mobile machines is often used because of safety issues. In addition to safety, remote control can be used to improve working efficiency and usability of the machine. A prototype of a hand-held remote control is designed to be used as a user interface of a mobile machine with an excavator while the machine is controlled remotely over short-range.
Since the remote control is designed to be used over short-range it provides congruent visual and voice feedback with the ordinary onboard user interface. In order to improve the feel of control an assisting force feedback function is implemented. The load of the machine is measured with a pressure transmitter. When the load tends to certain level information is provided to the operator. The idea is to inform the operator about the high load and possible power limitations, not to provide proportional force feedback.
Implementation of the system is introduced in this paper. The system is tested under real circumstances by using the excavator. Behaviour of the system during an excavation cycle is represented.

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For a new kind of automatic transmissions using proportional pressure valves to control the clutches directly, a two-degree-of-freedom controller is designed for clutch slip control during the inertia phase of the shift process. The controller is designed based on a low order linear model which is derived from dynamics of the proportional pressure control valve and the vehicle drive line. The feedback gain is calculated by robust pole assignment methods while the feed-forward compensator aims to improve system response. Finally, the designed controller is tested on an AMESim powertrain simulation model. Simulation results show that the rotational speed difference of clutch can track the desired trajectory well, and shift shock can be reduced by designing suitable feed-forward compensator.

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In this paper, a typical architecture of Electro-Hydrostatic Actuator (EHA) is described and modeled by the block diagram based on mathematic equations, which is a nonlinear accuracy model. The single PID, cascade PID and state feedback controllers are respectively designed and applied to this model for comparison analysis that focused on system stability, stiffness and dynamic characteristics. It is proven that the state feedback controller along with dynamic pressure feedback strategy could efficiently improve both static and dynamic performance.

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The optimum design of parallel manipulators is an important and challenging problem. Currently, much of optimization work has been done over several criteria related to workspace, stiffness, dexterity and conditioning index. Relatively few papers have taken the control problem into consideration. In this paper, an optimal design method based on generalized natural frequency is proposed, which aims to expand the bandwidth for the control of large hydraulic Stewart platform. A Lagrangian formulation which considers the whole leg inertia is presented to obtain accurate equivalent inertia matrix, based on which, the influence of design parameters on generalized natural frequency is studied. Conclusion drawn from numerical examples, based on more accurate model, demonstrates that the leg inertia especially the piston part plays an important role on the dynamics, and five design parameters (diameters of the moving platform and the base, piston mass, effective driving area and fully retracted leg length) influence the frequency most.

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Environmental protection regulations are becoming increasingly strict. By using water instead of a hydraulic mineral oil in power-control hydraulic systems we can make a very positive step in complying with these regulations. In this paper we present some preliminary results on twin-type hydraulic experiments, employing equal parts containing water and oil. Our initial findings suggest the need for modifications to the test rig, and a comparison of the behaviour between two similar hydraulic test rigs is shown. The main parameters measured during the investigation were the pressures, the spool displacements and the responses of the piston in the double-acting hydraulic cylinder. However, transient phenomena in the water and oil hydraulic test rig were also analysed and compared. Experiments were performed on systems with and without an applied load. The results reveal very different behaviours for the oil and the water hydraulics.

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The load characteristics and control of water hydraulic system for water-assisted injection molding (WAIM) are investigated through modeling and simulation. WAIM is an innovative process to mold plastic parts with hollow sections, coming with big advantages: high production efficiency and quality at low cost. The load characteristic is complicated owing to physical properties of polymer, distribution of temperature, flow rate and water channel geometry etc. The load pressure and flow rate are investigated with CFD simulation. An accumulator and a supercharger are applied in the water hydraulic system which is modeled in MATLAB and developed in laboratory. A differential pressure control strategy is provided to regulate the water injection pressure by a proportional relief valve. PI control is used and the steady-state error of step response can be reduced close to zero with integral compensation in closed-loop control. Finally, slope control of injection pressure is studied based on the developed system in simulation. The aim of this study is to improve the control process of WAIM based on the new design and differential pressure control. In addition, this provides an application and practice of water hydraulic proportional control technology.

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The goal of this paper is to detect internal leakages created by seal faults and also identify which seal is damaged from water hydraulic proportional valve using vibration and pressure signals which are analyzed using different data analysis methods. In this study water hydraulic spool valve is studied in a test system during extending and retracting strokes of cylinder while vibration and pressure signals from the valve are measured in normal and different fault situations. Feature extraction is performed using descriptive statistics and wavelet analysis to identify the most influential variables from the measured signals which are then used to classify the state of the system using Self-Organizing Maps (SOM).

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This study deals with a computer system for measuring flow rate of tap water flowing in a rigid pipeline in a non-contact method by using an acoustic emission (AE) sensor placed on a surface of a pipeline. The acoustic emission generated by tap water flowing at a constant flow rate in a pipeline is caught by the AE sensor experimentally, and the corresponding output of the AE sensor is converted to a root mean square (RMS) value. It became clear that the relation between flow rate and the corresponding RMS value can be expressed as a quadratic curve with good approximation. This quadratic curve is used as the calibration date for measurement of flow rate. A prototype of a flow rate measuring system based on a computer was constructed by taking account of the calibration data. It is shown in the experiment that the flow rate more than 3.21/min can be measured by using the measuring system proposed in this study.

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The objective of work described in this paper is to propose a new method of measuring gas leakage for pneumatic industry. The measurement is enabled by employing standard flow. Standard flow is used to determine the internal volume of the measured equipment. An algorithm is formulated to describe, to the extent possible, the relationship between gas leakage and standard flow. This measurement method deviates from the theoretical leakage values by less than 5%, and shows a good precision and scope compared with the traditional flow measurements. In addition, the proposed parallel connection based on standard flow makes easy operation and fast measuring possible, thus promising new area of application for pneumatic equipments.

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In industry, an unsteady flow rate measurement of gases is becoming important increasingly. Our group has been developed an unsteady flow generator with an isothermal chamber for gases and showed that the calibration of the dynamic characteristics for the tested flow meter was effective. However, not only the measurement of the instantaneous flow rate value but also the evaluation of the time mean value in the unsteady flow becomes important in industry. And it was difficult to control precisely the time mean value of the generated flow rate using the former unsteady flow generator which we developed. In this research, to improve the precision of the generated flow rate with the unsteady flow generator, we suggest the inlet flow rate control method with the sonic nozzle and the high precise pressure control system and apply this method to the developed generator. Moreover, we perform the experiments and uncertainty analysis and confirm the effective of the suggested method.

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The process that the low pressure gas in two gas tanks were reclaimed through air driven gas booster to one empty high pressure tank has been studied in this paper. Calculation formulae of performance parameters of the gas booster such as the inlet pressure, outlet pressure, volume of discharge and intake, air consumption in per cycle were obtained, and the change tendency of these performance parameters during its isothermal quasi-static processes was analyzed and several static characteristics and structural parameters that influences the booster's working performance were found out. The importance of dead volume and the way to raise the booster's efficiency was stated. The results are helpful for model selection, design and application of gas boosters.

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Information concerning the flow characteristics of pneumatic components is essential not only for selecting the right component at the design stage, but also for the simulation and the validation of different performances of a circuit. Recently, some works concerning the revision of the ISO 6358: 1989 standard [1] have concerned both the mathematical approximation of the mass flow rate characteristic [2] and the experimental way to obtain the characteristics [3, 4, 5]. This paper proposes to discuss the importance of the upstream and downstream pressures taken as references. Using experimental results, the flow behaviour of two real components is discussed pointing out two different cases, the first being close to a convergent nozzle, the second to a convergent-divergent nozzle.

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Recently, due to the ageing in Japanese society and the decreasing birthrate, an important problem of providing nursing care for the elderly has occurred. As a result, it is necessary to develop wearable systems to aid in nursing care. To realize the system, we require not only wearable soft actuators, but also compact and flexible control valve that can drive the soft actuator such as a pneumatic artificial muscle. The purpose of our study is to develop a flexible, lightweight and compact control valve which can be safe enough to be attached to the human body.
In this study, we proposed and tested a new type of control valve. The valve consists of a vibration motor and a check valve that made of a steel ball and an orifice in flexible tube. The operating principle of the valve is as follows. The valve is normally closed as a function of check valve. When the vibration is applied, the inner ball in the check valve moves and the valve opens. By giving continuous vibration, the valve can keep open. As a result, we find that the valve can control the relatively larger flow rate compared to their weight and size.

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ISO 6953: 2000 prescribes that forward flow-rate and outlet pressure until maximum flow-rate shall be measured with a constant inlet pressure and two or more outlet set pressures, and their relations shall be indicated by curves on a graph [1][2]. Since this test requires not only a huge air compressor, but also keeping continuous large flow-rate for a long time, enormous energy is consumed. Thus, this paper proposes a method to obtain flow-rate characteristics from pressure response on charging/ discharging compressed air into/from an air tank as an alternative test. This test method requires none of a huge air source, a long testing time, and enormous energy consumption.
In this paper, the above-mentioned alternative test was performed to some pressure regulators which had differentconstructions and sizes from one another, and it was verified that the results of the alternative test successfully corresponded to the one by ISO 6953 using a flow meter. Examination to optimize the test method was also discussed. The running cost to operate the test, which consists of labor costs based on the test time and energy consumption, was reduced to approximately one-fifth.

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This study is aimed at developing a small-sized air pump using an originally contrived balloon vibrator for wearable devices. The developed pump can compress air by vibrating a balloon vibrator which is composed of a doughnut-shaped balloon diaphragm fitted with a circular stainless steel plate. The balloon diaphragm is filled with air. This pump has characteristics as an oil-free, doesn't leak air at all, and has a longer stroke than existed diaphragm pumps. Therefore, this pump is expected to have higher discharge performance than existed diaphragm pumps. In addition, it is also expected to develop an output variable air pump by controlling the inner pressure of balloon. In this paper, the structure of the developed pump is described, and then the fundamental characteristics of this pump are evaluated.

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Shock absorbers are vital devices for high speed driving with pneumatic cylinders and it is important to select the suitable shock absorbers to use pneumatic systems without trouble. It is commonly believed that the absorbed energy by the shock absorber is the sum of kinetic energy and thrust energy, which are important parameters to set up the pneumatic system. In a typical selecting method of the shock absorber, the value of thrust energy is estimated from the value of only supply pressure. However, the selecting method has been regulated for hydraulic systems and the estimated value of thrust energy in the pneumatic systems is not approximate, because inner pressures in the pneumatic cylinder is not stable and quite different from the supply pressure. Finally there are many bad combinations of the cylinder and shock absorber in the pneumatic system.
In the research, we experimentally investigate the formula for estimation of the thrust energy, which is defined in the selecting method of shock absorbers. Experimental results show that accuracy of the formula to select the shock absorber is inefficient. Additionally we examine on parameters that affect the thrust energy and compensate the formula.

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This paper deals with the simulation of the dynamic characteristics of an air gripper by a new bond-graph method. Recently, pneumatic systems are widely used with food equipments and wrapping ones, etc. However, the design and the improvement of those pneumatic systems take much time because they depend largely on the experience of designers. In order to make them more effective and systematic, it is necessary and important to predict the dynamic behavior of the system beforehand by computer simulation. An air gripper is often used as an actuator in a pneumatic system. However, there are few reports focused on its dynamic characteristic as authors know. In this paper, to obtain asuitable mathematical model for an air gripper and to show the usefulness of the proposed bond-graph method, both experimental and simulation studies are performed. In modeling for pneumatic field, the new bond-graph method is employed, which had been proposed by some of authors. In the bond-graph method, a pneumatic system can be represented by using conventional 1-port C and 1-port R elements.

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A simple way to increase the extinguishing water surface area is to atomize water into fine drops. The smaller drops are developed, the better use of water properties can be implemented and less water is consumed in fire fighting. The automatic impulse extinguishing is created. The main aim of the investigation is to develop the approach to investigate the dynamic and hydrodynamic processes in the extinguishing device. The mathematical model of the extinguishing device is presented, where the flow of liquid and gas and the interaction of liquid with the gas are taken into account. The flow of fluid in a hydraulic system is described by a system of equations of a hyperbolic type, which is solved by a characteristics method. An instance of the mathematical simulation of the activity extinguishing device is shown.

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Jet vacuum ejectors currently used have a defect of large air consumption due to the need of continuous and constant air supply. To solve this problem, a novel technical structure of the jet vacuum ejector with flow self-regulation by an adjustable cone has been investigated. In this paper, the structure, key technologies and experiment of this new jet vacuum ejector are introduced. In the new ejector, by means of the adjustable cone, the effective cross section at the jet nozzle throat could be adjusted so as to realize the reduction of air supply and achieve energy saving. For this, a key technology for the new structure called chamber-separating pneumatic-magnetic driving is studied, . in which a vacuum detecting-differential pressure actuating and non-contacting pneumatic-magnetic driving with a coaxial magnetic ringaxial structure are implemented. Experimental results for the flow self-regulated vacuum ejector have shown that the vacuum response time and maximum vacuum of new ejector are almost equivalent to the constant-area vacuum ejectors with the relative parameters, but the air consumption could save about 14.8%.

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Air cylinders have been used with meter out control. In these cases, the outlet pressure of air compressors are set at 0.5-0.7 [MPa] for consumption air saving, and so downstream pressure of the actuator is low level, such as nearly atmospheric pressure. For pneumatic energy conservation, it is most important that supplying air use effectively. A lot of small cylinders are worked in automatic factory product systems, and air supply lines are longer between compressor and these cylinders. So, in a plant, energy consumption of pneumatic system is bigger and gets big losses. In this paper, the authors propose that the exhaust pressure of the cylinder hold middle level (0.2-0.5 [MPa]), and so the downstream available for running air blow guns etc. This paper shows the air cylinder dynamics at start and stop, then the parameter are exhaust pressures, cylinder load, supply piping length. Assuming that exhaust flow is used effectively, the proposal method available to prove energy conservation of pneumatic systems. For example, the exhaust pressure setting 0.2 [MPa] reduce 15% of pneumatic energy consumption.

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In previous researches, a novel portable pneumatic power source, called a Dry Ice Power Cell, and a novel pneumatic power assisted lower limb for outdoor walking powered by Dry Ice Power Cell, called a DPAL were developed. In this paper, an improvement in design of the DPAL is presented. For those people whose muscle and balance remains in good condition but who have joint pain (hip or knee joint) in their leg and are unable to walk outdoors for long, the developed device can partially lift the patient in a comfortable way by pneumatic cylinder when the affected leg touches the floor, reducing the load to which it is subject as well as the pain joint forces, thus relieving pain during walking. The developed device has the characteristics of a simple structure, low weight, easy to don and doff, and with sufficient capability to bear about 40% of the body weight. In this paper, the structure, function and experiments are described.

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This paper discusses an Internet-based tele-rehabilitation system with Single-Master and Multi-Slaves, which aims to achieve the situation where multiple stay-home patients in scattered places can share rehabilitation instruction from one physical therapist. After the introduction of whole system's concept, ‘ Passive-Active Shift’ rehabilitation is proposed considering the varied symptom of different patients. Then after introduction of master slave system's designing, for passive rehabilitation which is carried through internet-based bilateral teleoperation system by therapist who is necessary, novel control architecture to ensure the stability of tele-rehabilitation system with time delay is proposed. For active rehabilitation, game-based active rehabilitation is proposed to draw the patients' mind into rehabilitation which is important to reestablish neuromuscular control.

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Among the elderly person, most of their injuries are reported to be caused by falling down with stumbling. It is due to their shuffling walking style resulted from deterioration of their dorsiflexion muscle force along with aging. Walking plays an important role in their independent day life. In this study we aim at developing a wearable walking support equipment embedded into shoes for a purpose of fall prevention of elderly person. A commercial product of Ankle Foot Orthosis is introduced and newly developed wire type pneumatic actuator is equipped on to support dorsifl exion motion during swing period at walking motion actively. In generally, these kind of active supporting systems require power source. We propose a driving scheme with no use of electric power, but with only potential energy of the wearer. Required specifications for the equipment are derived and the validity of proposed walking support shoes is verified through some experiments.

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Along with declining birthrate and a growing proportion of elderly, to increase the number of people who requires nursing is anticipated. As a result, the shortage of the workers in medical welfare field is serious concerns in Japan. Then, if the wearable power assist device can be developed, many people can live independent life with a slight degree of assist. The purpose of this study is to develop a power assist wear to assist an activity of daily living of aged or disabled person. For the actuator, it is required to have a compact, light-weight and flexibility. Developed sheet-like curved type pneumatic rubber muscle is made of rubber band and has a high affinity for human skin. In this paper, the characteristics of the sheet-like curved type pneumatic rubber muscle and the power assist wear are described.

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Due to the development of the larger size of FPD, the conveyor system, especially the lifting system, become a significant topic. This paper aims to develop novel lifting system with the AC servo driving and the pneumatic-balanced system for the new generation of LCD glass substrates. Owing to the large variation range of the loading in the new generation lifting system, the pneumatic-balanced system is developed for counterbalanced the weight of the loading for reducing the loading power of the AC servo motor. A PC-Based control system is developed for achieving better response and position accuracy. Adaptive sliding mode control with function approaching technique is used in this paper as the control strategy. In order to improve the jerk problem during the motion process, path control is used. The proposed new lifting system with pneumatic-balanced technique is implemented and verified through simulation and experiment.

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Pressure reducing valves are widely used to maintain the pressure of gas reservoirs to specific values. When highly pressurized air passes through the orifice structure, considerable noise occurs at the downstream side. To solve this problem, we have developed a radial slit structure. The radial slit structure reduces the noise by suppressing the generation of turbulence and shock wave at the downstream. In this paper, we newly develop a pressure reducing valve applied the concept of the slit structure. At the former slit structure, the height of the radial slit was fixed. In the new valve, we proposed an improved slit structure that the height of it is variable. Coned disk springs are installed between the disks and the height of it is controlled from 0 to 50m with a pneumatic cylinder. As a result, the new structure can successfully control the flow rate and control the pressure in a reservoir. The performance of the valve is investigated experimentally and confirmed that noise can be reduced with the radial slit structure.

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Air-powered engine is a promising one of the low emission engines, for the advantages of its simple structure and complete zero-pollution. In this paper, the two-stage expansion Air-powered engine (TSEAPE) was studied in theory fi rstly and then experiments. Based on the model of TSEAPE that has been developed on the thermodynamics and mechanics analysis, the effects of bores ratio on the performance of TSEAPE are investigated by simulation. The results of simulation indicate that the TSEAPE will performance well when its bore ratio is about 1.4, which is a good balance between the power output and the efficiency. Guided by the results of theory analysis, a TSEAPE was developed based on an existing internal-combustion engine. The experiment results of this prototype engine on a test bench show that TSEAPE runs stably on bore ratio 1.4 and has better performance at a low speed

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Plant cutting is a technique for propagating plants in which a piece of the source plant, called the cutting, is placed in the soil to grow as an indipendent plant. The cutting produces new roots and stems, and thus becomes a new plant. This technique is used in workshops to reproduce plants for selling. In this paper we are presenting a system to automate the plant cutting process of ornamental plants. The process starts with a single stem of the parent plant, with no branches. The system is able to cut the stem for producing the cutting, to remove the leaves from its basal part, and to manipulate it for the hormone subministration and for the insertion in the substrate. The design and the prototype of the automation machine, based on the pneumatic technology, is presented in this paper.

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This paper presents a hose type rescue robot with new movement abilities, for passing through narrow spaces and searching for victims under debris. At the disaster site, the fiber scope and the pole equipped with a camera on its head were previously used to search for victims. However, there are problems with going into complex curved and rugged spaces due to the friction between the robot body and surface of debris. So in this study, the hose type robot named Grow-hose-I, growing with a rapid motion type hose, is proposed which can move smoothly with no friction between the hose and the ground surface. The hose is composed of flat tubes driven by pneumatics, and it can be actively curved to enable steering.

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In the teleoperated minimally invasive surgery systems, measurement and display of sense of force to the operator is aproblem In this paper, we have developed a master-slave system having 7-DOFs for laparoscopic surgery, which can provide force feedback to the surgeon without using force sensors at the slave manipulator. Pneumatic actuators are used for the slave manipulation because they are effective for haptic devices due to the facility in measurement and control of their driving force. A control method to compensate the effect of the pipeline between the control valves and the actuators is proposed and applied. Then, an impedance control is applied to the slave manipulator and an admittance control is applied for the master manipulator. Finally, a bilateral control is achieved by combining the controllers. Experimental results show that the developed system successfully display the contact force on the slave side to the operator on the master side.

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Abstract-In general, it tends to become a complex and expensive structure in the controlling of flow rate. In this paper, a simple structure and compact flow rate servo system is shown. It is easy to carry by integrating needed element, that is, the solenoid valve, the isothermal pressure vessel, the pressure sensor and oneboard controller of on-off method, although, the external compressor is needed. The signal measured with the pressure sensor is sent to the controller, and the proper control signal is feedback to the switching transistor according to on-off timing of the solenoid valve. In this method, the small pressure fluctuation caused by switching action of solenoid valve can not be avoided, however, this pressure fluctuation enables to examine the actual output flow rate by on-line sampling the pressure and calculation using micro processor on controller. So we execute continuous flow rate controlby this compact system alone, and are able to change the output flow rate freely according to manual set up or external control signal. For the evaluation of this system, the blowing up device is adopted to confirm the accuracy of flow rate that is constantly controlled ball height apart from seat.

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The pressure depression is usually observed just after the gas supply hole. In order to improve the pressure distribution, a new type of aerostatic bearing (NT) is designed, which has a tapered chamber at the outlet of the gas supply hole. The Fluent software is used to simulate the working conditions of aerostatic bearings. The simulation results show the simulation method can effectively estimate the pressure depression and the pressure distribution of the NT is remarkably improved compared with the traditional annular orifice type (TT). It's found that the characteristics of the Mach Number (MN) distribution of the NT are different from those of the TT and the tapered chamber can effectively reduce the velocity at the bearing clearance entrance. A test rig is built. Thepressure distributions are tested and the simulation results of the NT agree well with the experimental results. The simulation method provides a good theoretical method to study the aerostatic bearings and the new design will be helpful to the development of high load capacity aerostatic bearings.

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It is well-known from our previous study that LC (liquid crystal) circumrotates in a mini cylinder by a rotating electrical fi eld. The possibility of the development for a motor based on the above idea is investigated in this study. In the experiments, electrodes are located both at the bottom and on the side wall of the cylinder, in which the LC and the rotor are placed. The influence of the viscosity on rotation speed of the rotor is investigated. Moreover, the theoretical study on torque generation is expected too.

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In this study, we investigated the mechanism of polishing the inner wall of a tube utilizing a magnetic compound fluid (MCF) from a hydrodynamic viewpoint. We conducted polishing experiments by filling a tube with a MCF consisting of abrasive grains and applying a rotating magnetic field perpendicular to the tube axis. In addition, in order to clarify the polishing mechanism, we performed visualization experiments by observing the behavior of the abrasive grains and measuring the pressure distribution on the inside surface of the tube using a hydrodynamic technique. This study demonstrated that a magnetic field distribution for effective polishing should exist in the region furthest from the centerline between the magnetic poles in the tube. At this position, the abrasive grains are located on the sides of the walls of the inner tube of the clusters formed along the line of magnetic force and the pressure generated is effective for polishing. The pressure distribution has a flat valley profile. Therefore, the radial force of clusters formed near these locations is considered to impart a processing force to the abrasive grains

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In this study we aim to realize an actuator that is comparable with a natural muscle from a viewpoint of flexibility, the output force and the responses. We constructed the Shape Memory Alloy (SMA) coil actuator protected by “a rolled film tube” with the high heat resistance and the high flexibility, and it is named “the unit cell”. The SMA coil in the unit cell is cooled down by inert liquid flowing through the rolled film tube. Then we constructed an actuator named “a motor unit” with the larger output force by bunching up seven unit cells, and the characteristics of the motor unit are investigated by the experiments in which the motor unit is driven in Pulse Frequency Modulation (PFM) found in the bio-motion. The result of the experiments shows that the static characteristics of the output force and the displacement to the input pulse frequency in the motor unit near proportion relations in comparison with the unit cell still more and the output force increases almost seven times as large as the unit cell. Consequently, it is found that these actuators proposed can be employed as applications to a flow control valve and an artificial arm.

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Immersion lithography has been proposed as a method for improving optical lithography resolution to 32nm. The premise behind the concept is to increase the refraction index in the space between the lens and wafer by insertion of a high refractive index liquid in place of the low refractive index air that currently fills the gap. During the scanning and exposure process, immersion liquid is injected into the space between wafer and lens with certain inlet pressure and angle. Because the liquid will act as a lens component during the lithographic process, it must maintain high uniform optical quality. One source of optical degradation may be due to lens distortion caused by the pressure distribution nonuniformity in the fluid flow field. Consequently, any deviations of pressure distribution on flow field boundary in direct contact with lens may damage the uniform optical path.
Three-dimensional computational fluid dynamics models were created to assess the pressure distribution characteristics relevant to flow rates and injecting angles of immersion liquid. Flow field stream patterns were discussed corresponding to dispense port numbers. The numerical simulation results were presented, featuring lens normal and shear pressure and injection flow, considering fluid injecting velocity, dispense ports quantity, and direction angles.

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