Hydraulic Power Supply Research Articles

Possible Alternatives for Deep-Water Gas Charged Accumulators

Gas Charged Accumulators are widely used in Drilling operations; however, the current Accumulator design methods are inadequate for Deepwater Drilling. Gas-Charged Accumulators are used in subsea drilling as well as production operations. One important application of accumulators is in blowout preventers (BOPs). BOP’s are designed to shut in a well under pressure so that the well control procedures could be implemented. Control Systems for the BOPs should be highly efficient hydraulic systems and operate in as short a time as possible. Supplying enough volume of pressured hydraulic fluid to operate those emergency functions is essential. To have the necessary quantity of control fluid under pressure requires storing this fluid in accumulators. Gas Charged Accumulators are the most commonly used accumulators in Drilling operations. These accumulators are not efficient at all in Deep waters, and there are not many alternatives for them. This paper looks into possible alternatives for Gas Charged Accumulators in Deep Waters. Supplying enough volume of pressurized hydraulic fluid to operate the BOPs for emergency situations is essential for Deep Water Drilling. This requires storing the pressurized hydraulic fluid in accumulators. A problem may arise when the wellhead is at water depth of more than 3500 ft. In deep water drilling, the accumulators should be placed on the subsea BOP stack to reduce hydraulic response times and provide a hydraulic power supply in case of interruption of surface communication. Hydraulic fluid capacity of an accumulator may drop to 15% of its capacity on the surface and even less, depending on the water depth. The reason for this is that the nitrogen gas does not behave like an ideal gas as we go to very deep water, due to high hydrostatic pressure at that water depth. We have to look for alternatives to Gas Charged Accumulators. It has to be something that is able to store energy, but unlike the nitrogen, its functionality should not be affected by the increasing hydrostatic pressure of water. The possibility of the use of springs and heavy weights as possible replacements for nitrogen in structure of accumulators will be discussed in this paper. High hydrostatic pressure of deepwater should not affect the functionality of these mechanical accumulators. Transferring bank of accumulators to the surface and connecting them to the BOP with properly sized and rigid pipes can decrease response time to an acceptable extent to satisfy regulations and standards. This idea can be considered as an alternative solution too. We have to include the hydrostatic pressure of water in the usable fluid calculation. A low pressure tank located on the sea-floor can dismiss the negative effect of high hydrostatic pressure of seawater. This alternative idea is also discussed. Efficient deep water accumulators would reduce the number of accumulators required in deepwater and cut the cost of the project. With the advent of such efficient accumulators, we can hope that one of the numerous problems of deepwater drilling has been solved and we can think of drilling in even deeper waters. Key words : Drilling operations; Deep-water gas charged accumulators; BOPs

Design and development of a novel redundant and fault-tolerant actuator unit for heavy-duty parallel manipulators

This paper proposes a novel dual-input/single-output actuator unit, called a redundant and fault-tolerant actuator (RFTA), designed for heavy-load parallel manipulators. After the definitions of redundant and fault tolerance are given, the principle of the proposed RFTA is described using its two working processes. According to the derived kinematics, 12 fault modes caused by two different input velocities are developed and classified, and the physical meanings are represented correspondingly. Mechanical transmitting properties of the proposed RFTA are analysed respectively. On the other hand, RFTA, as a dual-module hot spare architecture to achieve high reliability and safety, with its complete redundant structure can be called Multiple Births Structure (MBS) and is different form the traditional partial redundant structures – Siamesed Births Structure (SBS). The reliability models show that RFTA is more reliable than SBS. Three guidelines – the select guideline, the design guideline, and the operation guideline – are suggested. Those design guidelines are useful to designers and users. A prototype of RFTA and its control system are developed and the relevant experiments are carried out. The experimental results demonstrate that RFTA is able to not only supply double driving force but also tolerate some local faults caused by out-of-syncs. RFTA provides heavy-duty equipment, especially large-scale parallel manipulators, with a new probability in changing their drive mode, from the hydraulic power supply to the motor drive. Furthermore, this paper also demonstrates that RFTA has some potential applicable prospects under heavy-duty environments, such as a large-scale parallel earthquake simulator and an electric press with heavy duty cycles.

Design and Simulation of Electro-hydrostatic Actuator with a Built-in Power Regulator

The electro-hydrostatic actuator (EHA) is a kind of power-by-wire (PBW) actuator that converts the electrical power into localized hydraulic power for flight control. By removing the central hydraulic power supply together with hydraulic pipes, an EHA's reliability and efficiency are greatly improved but its frequency width and stiffness decreased. To overcome the drawback, this article proposes a novel structure of EHA associated with a power regulator. Composed of a high-pressure accumulator and a proportional valve, it can store and harness the hydraulic power flexibly according to the changing control requirements. The concept of transferred volume is put forward to estimate the capability of the power regulator. The actuator output position can be kept fixed with a hydraulic lock. The compounded control is specially developed to ensure the actuator system to operate in a correct manner. The simulation results indicate that the new-brand actuator results in efficient expanding of the system frequency width with an optimal power supply.

Vehicle Suspension Measurements: Evaluation of the Benefits of Dynamic over Quasistatic Kinematics and Compliance Testing

Abstract Vehicle dynamics packages can be used to simulate handling or braking maneuvers that would otherwise need to be performed outdoors. Many of the parameters for these types of vehicle models are determined through kinematics and compliance (K&C) measurements. Machines that perform these measurements apply various forces or moments and measure the response of the vehicle. The rate that these forces or moments are applied can be quasistatic or dynamic. Machines that are capable of performing dynamic tests are more expensive due to the need for inertia compensation, sensors that can acquire data at higher rates, and larger actuators or hydraulic power supplies. However, it is possible that measurements of dynamic vehicle response may increase the fidelity of parameter identification, compared to the sole use of quasistatic tests. One reason that parameter identification may be more accurate is the rate of force and moment application in dynamic tests is more like those in the actual maneuvers that are desirable to simulate. A study was performed to determine where the advantages of performing dynamic K&C testing lie. Quasistatic K&C tests, along with dynamic tests performed at several frequencies up to 3.0 Hz, were performed on the front axle of a front-wheel drive compact sedan, using an MTS Systems High-Rate K&C Machine. Assessment of any advantages of dynamic K&C testing has been made through correlations of the vehicle response between dynamic and quasistatic tests.

Design and Control of a Ship Motion Simulation Platform from an Energy Efficiency Perspective

AbstractMost hydraulic servo systems are designed with little consideration for energy efficiency. Pumps are selected based upon required peak power demands, valves are chosen primarily for their rated flow, actuators for the maximum force. However, the design of a hydraulic servo system has great potential in terms of energy efficiency that has, for the most part, been ignored. This paper describes the design and control of a large-scale ship motion simulation platform that was designed and built at Oak Ridge National Laboratory for the Office of Naval Research. The primary reasons to incorporate energy-efficiency features into the design are cost and size reduction. A preliminary survey of proposed designs based on traditional motion simulation platform configurations (Stewart Platforms) required hydraulic power supplies approaching 1.22 MW. This manuscript describes the combined design and control effort that led to a system with the same performance requirements, however requiring a primary power supp...

Design of a P-wave seismic vibrator with advanced performance

ABSTRACT For optimal seismic imaging, the vibroseis method requires the vibrator to generate synchronous, repeatable sweeps over a broad frequency range and output the ground-force energy with minimum harmonic distortion. This requires re-evaluating each element of the vibrator system to ensure that it contributes to the success of the method. Key factors that cause the vibrator to suffer from severe harmonic distortion are fluctuations in the hydraulic power supply pressure, flexing of the baseplate, coupling or loading between the baseplate and the ground, nonlinear servo-valve flow-pressure characteristics, and servo-valve characteristics near null. This paper examines these factors and describes the design of a new P-wave vibrator by ION (previously I-O) to improve seismic resolution. Experimental results demonstrate that the newly designed vibrator dramatically reduces harmonic distortion in the ground-force signal under various coupling conditions, particularly on hard and uneven ground. With the high-frequency controller and Pelton DR valve, a broad-band sweep frequency is achieved. Cavitations in the supply pressure, a long-standing problem in vibrator mechanics, are almost completely eliminated.

FLOW RATE CONTROL OF VARIABLE DISPLACEMENT PISTON PUMP WITH PRESSURE COMPENSATION USING NEURAL NETWORK

One of the most important components in hydraulic circuits is the pump that generates hydraulic power supply. The performance and the versatility of a variable displacement piston pump are, to a large extent, determined by its controller. Upgrading of existing controllers is considered one of the major means of improving the characteristics of the pump. The dynamic performance of hydraulic systems with a demand flow supply not only depends on the performance of the flow modulation valve, but also on the performance of the pump. In this study, the performance of soft computing methodology, trained Neural Network (NN) based on the conventional PID controller, is used for the control of a swash plate displacement while the compensation of the effect of the back up pressure is implemented by inverse NN model. The feasibility of system is simulated and issue of implementation such pumps control is established. It is seen that the use of the proposed methodology results in some desirable characteristics.

FBW 항공기의 DDV 구동장치에 대한 구동전류 고장 모니터 설계

This paper deals with a driving current fault monitor design methodology for a DDV actuation system which has a dual hydraulic power supply system, and triplex electric control capability. A fault existing among these redundant channels should be detected accurately and removed timely, and the remaining channels are to be reconfigured in order to compensate the role of a removed faulty channel. An integrated analysis on the aerodynamics, flight control laws, and DDV actuation system is essential for the design of an actuation system fault monitor. A method to define a fault transient boundary which specifies a maximum travel of an actuation system caused by the first faulty operation is proposed based on the top level requirement on the fault effect specified in MIL-F-8785C.

Simulation of the perceptible feed-forward and feed-back properties of hydraulic power-steering systems on the vehicle’s handling behavior using simple physical models

Today, often complex component-oriented simulation models are used to study the influences of hydraulic power-steering systems on the vehicle’s handling properties. In these simulation models, we have a detailed description of the vehicle suspension components (links, joints, springs, etc.) extended by complex component simulation models of tires, bushings, and of course also by power-steering models. These power-steering models contain a detailed physical description of the complex mechanical and hydraulics properties of the system, like friction in seals, aspects of hydraulic power supply, etc. On the other hand, there is a need for simple model approaches used for basic assessments and system development. These simple models should represent all the essential properties of the vehicle’s handling behavior, without the need for the large-scale parameter setup and compute-time requirements of the more complex models. For many applications in handling, we use the class of single-track two-wheel bicycle-type vehicle models. With some nonlinear extensions, these models can represent the complete operating conditions of the vehicle. The parameterization of these models can be achieved online while driving or offline by analysis and identification, on the basis of some standard test maneuvers. In these models, all properties of steering, suspension and tire are condensed to the cornering stiffness or side-force map, a separation e.g. of the steering system influence does not take place. This article shows how modeling of a hydraulic power-steering system can be done to represent the essential feed-forward and feed-back properties, and how this model can be integrated to the complete vehicle’s description. This new model approach gives a better insight into the four-pole properties of steering systems and introduces a separation between the steering system and the suspension even in simple model classes.

三井-MAN B&W 7S50ME-C : 電子制御エンジンの開発(FP5 レシプロエンジンの環境対応技術)

This paper describes the development of Electronically controlled marine two-stroke diesel engine 7S50ME-C for Tsuneishi Shipyard Sno.1262, and the abstract is made as follows : (1) Generally explained are newly introduced engine components such as Hydraulic Power Supply, Hydraulic Cylinder Unit, Cylinder lub. Oil System, Tacho System and Engine Control System(ECS). (2) Two operation modes are prepared in the operating system as standard. One is "Economy mode", which can comply with the present IMO Nox emission limits, and the other is "Emission mode", which can comply with more strict emission limits. It is possible to change the operation mode by the touch-panel on the Main Operating Panel(MOP). (3) Engine Control System has redundancy with two concepts, one is a complete backup operating system, and Controller called as "Multi Purpose Controller(MPC)", which is used for all control Units, is compatible. (4) ECS controls maximum cylinder pressures for different ambient conditions, such a ship sailing in tropical sea or in arctic sea, by monitoring the scavenging air pressure, in order not to increase the Nox emissions.

Testing with a small footprint

A new series of single footprint hydraulic universal testing systems for metals, fasteners, composites and concrete has been launched by Instron. The SATEC series combine the frame, hydraulic power supply, electronics and control panel into a single machine, reducing floor space requirements by more than 60 per cent. The LX models range in capacity from 150 kN to 1000 kN, while the DX ranges from 300 kN to 3000 kN. The DX features two test spaces allowing tension and compression tests to be performed in separate areas. The systems are designed to support automatic extensometers. This is a short news story only. Visit www.metal-powder.net for the latest metallurgy industry news

Integrated design of structures

Abstract : It is shown that for highly sophisticated, naturally unstable airplanes flying supersonically a joint strategy to lay out the flight control system while minimizing design loads must be adopted. The selection of control surface geometry must be performed utilizing all possibilities from overall structural optimization including aeroelastic tailoring for primary carbon fibre structures. In the proposed design philosophy the behavior of the elastic airplane structure must be introduced and optimized in the very early design stage. It is shown in the paper that the required control surface hinge moments can be reduced by optimizing mass penalties and efficiencies. Minimizing installed hydraulic power supply has also a beneficial effect on engine performance at low speed, high altitudes.

A high‐power, low‐frequency hydroacoustic sound source

A low‐frequency sound source of high acoustic output (214 dB re 1 μPa at 1 m) has been developed by Hydroacoustics Inc. The projector has been configured to operate over two distinct frequency bands, with a bandwidth of approximately 40% of each band‐center frequency. The conversion between the two bands requires relatively simple hardware changes, principally in the radiating structure. The primary input power to the source is in the form of three‐phase electrical power to an electric motor driven hydraulic power supply which is an integral part of the projector structure. Conversion of the input power to acoustic energy is accomplished through a rugged hydroacoustic power amplifier which responds to a low level signal voltage and reproduces this waveform as acoustic pressure/flow acting in a centrally located fluid cavity. Two opposed, edge‐supported radiating flexural disks are center driven by drive pistons which communicate with this fluid cavity. The entire structure is very rugged and capable of operation to great depths. Analytical modeling of this projector has been developed by the Naval Ocean Systems Center in conjunction with Hydroacoustics. This model includes the radiation loading, the flexural modes of the radiating disks, the hydraulic power supply, and the two stage hydraulic amplifier—including those nonlinearities associated with large power transduction. In water calibration test results in both bands will be presented, as well as a comparison between these results and the modeling effort. [Work supported by the Naval Electronics System Command.]

Hydraulic Power Supplies and Control Circuits

Hydraulic Power Supplies and Control Circuits

A New Offshore Pile Aligning System

This paper describes the design and application of a pile aligning system that makes connecting add-on sections of piles in offshore platforms easier. Field operation of the system in the Gulf of Mexico is discussed. Design concepts, actual hardware used to implement these concepts, and successful operation of hardware on the job site also are discussed. Introduction Steel platforms are conventionally pinned to the ocean floor with large-diameter piling, which is driven through the legs of the platform and/or through guides around the base of the platform. When platforms are set in deep water, it is not feasible to handle the pipe in one section. It is necessary to add on additional sections as the pile meets and then is driven into the ocean floor. The platform itself is grounded to the sea bottom, whereas the derrick associated with a derrick barge for handling the add-on pile sections floats on the ocean surface. Consequently, there is relative motion between the section of piling to be added and the pile that already has been installed in the leg or guides around the platform. The amount of motion is, of course, a function of the wave action or sea state on the derrick barge. When the weather becomes a factor, it is common to wait for calm seas, even though the operation may cost as much as $50,000/day while waiting.The piling used today is either 48- or 54-in. diameter and some is more than 90 in. The add-on sections usually are joined to the pile by welding. Because welding must be performed in the field, it takes 3 to 12 hours or longer per connection, depending on wall thickness. Time is per connection, depending on wall thickness. Time is saved by using mechanical connectors that theoretically eliminate welding time and pay for themselves, even though they may never be recovered. On the other hand, experience to date has proven that with the motion, it is impossible to align the connectors and connect them successfully. Sometimes the operation takes longer than welding; therefore, these connectors are used reluctantlyWhen pile is driven through guides around the base of the platform (skirt piles), sometimes it must be cut off at the base of the platform to remove the upper section. Upper sections of pile are not necessary to improve jacket stiffness and, thus, considerable savings result. When the upper section of the driven pile must be removed, we need a disconnector at the appropriate level, which usually takes the form of the described mechanical connectors. During removal these upper pile sections must be held as well as disconnected. This study describes a way to speed up connecting time and make it more feasible to use mechanical connectors where possible. Design Solution The crux of the problem is the relative motion between the add-on pile and the pile already installed in the jacket. Eliminating this relative motion results in a satisfactory solution to the problem. Among secondary advantages of using mechanical connectors would be the ability to rotate the piling for connecting and disconnecting. Also, if the pile could be lowered or raised independently, several piles could be run simultaneously. This could result in piles could be run simultaneously. This could result in significant time savings for the over-all operation.The proposed solution to these problems is called the Pile Aligning System (PAS). PAS has four components: Pile Aligning System (PAS). PAS has four components:the aligning structure (Fig. 1),the self-powered hydraulic power supply (Fig. 2),the pickup elevator. andthe driving head (Fig. 3). JPT P. 1061

Flying controls

THE A300B employs fully powered flying controls, operated by hydraulic power, with no reversion to manual control. The hydraulic power supplies are ‘triplexed’ to the banks of three jacks at each primary control surface. Jack sizes are chosen so that full control over the flight envelope is available with only two hydraulic systems working. Should a further system have to be shut down for any reason, the one remaining set of jacks will still provide sufficient power for control of the aircraft, including landing.

An automated test facility for rock mechanics research

This paper describes the design, development and operation of a newly completed test facility in the Department of Mining Rock Mechanics Laboratory at The Pennsylvania State University. The facility contains an electronically programmed electro-hydraulic loading system capable of developing compressive and tensile loads of up to 200,000 and 120,000 lb respectively. Programming facilities available make it possible to carry out creep, stress relaxation and fatigue studies as well as experiments under controlled rates of loads strain and deformation. Two hydraulic power supplies are included for developing confining and pore (internal) pressures during triaxial loading experiments. Facilities are available for monitoring strains, loads, pressures and temperatures; these include a digital data acquisition system capable of monitoring up to 200 channels of experimental data at a rate of 20 channels/sec, and three dual-channel strip chart recorders and an X-Y plotter which allow continuous recording of selected variables. The overall facility has been developed for routine use by faculty and graduate students. Although considerable time and effort have been expended in designing the facility, it is expected that the convenience and reliability inherent in such a facility will accelerate rock mechanics research many fold. Research projects presently utilizing the new facilities include studies of incremental creep, and fatigue in geologic materials.

Hydraulic Control Systems

Hydraulic Fluids. Fluid Flow Fundamentals. Hydraulic Pumps and Motors. Hydraulic Control Valves. Hydraulic Power Elements. Electrohydraulic Servovalves. Electrohydraulic Servomechanisms. Hydromechanical Servomechanisms. Nonlinearities in Control Systems. Pressure and Flow Control Valves. Hydraulic Power Supplies. Index.

Research and Testing

Equipment, Programmes, Techniques and Projects. Variable‐pitch drop‐out ram air turbines which provide a stand‐by electrical or hydraulic power supply in an emergency on VC10 and Trident airliners, are being tested at Dowty Rotol Ltd.'s Gloucester plant by an ingenious technique using a stroboscope in conjunction with a closed‐circuit television system, both supplied by EMI Electronics Ltd.

Use of a Hydroacoustic Transducer in Continuous Seismic Profiling

The hydroacoustic transducer is an acoustic radiator actuated by an electrohydraulic positioning servo. It was used during April 1963 as a low-frequency, broad-band source in continuous geophysical profiling experiments aboard Hudson Laboratories research vessel J. W. GIBBS (T-AGOR-1). The transducer has a 2-ft diam acoustic piston driven by a 14-in.-sq. hydraulic ram, fed through 200 ft of hydraulic lines from a 35 GPM, 2000- to 3500-psi, shipborne hydraulic power supply. The transducer controller consisted essentially of a 10-W electronic servoamplifier fed by various audio signals. The experiment is similar to that described by Clay and Liang [Geophysics 27, 786–795 (1962)]. In this experiment, most of the data were obtained with either 1-sec 100-cps bandwidth chirps or noise pulses within the total range of 80–400 cps. Short 250-cps pings were also used. The signal returns were processed with a polarity correlator. In this system, one compresses the coded pulse of relatively long time duration and low amplitude into a short pulse of high amplitude. In the 200- to 300-cps range, the radiated pulse is estimated to be about 900 J energy and 500 J in the 100- to 200-cps frequency range. Seismic profiles were made in the Hatteras Abyssal Plain area in water depths of 3000 f and subbottom penetrations of 34- to 114-sec travel time were recorded. Two and three subbottom reflections were often observed. [Hudson Laboratories, Columbia University Informal Documentation No. 33. This work was supported by the Raytheon Company and the U. S. Office of Naval Research.]