Hydraulic ebook (4)

Q18. A Study on a Full-electric Control System of a Hydro Static Transmission for Construction Machines

Hydro static transmission (HST) [1], [2] has been widely used for continuous variable transmission for construction machines. The HST consists of a pump and a motor. The pump is a variable displacement pump so that gear ratio of the HST can be controlled continuously. Conventional technique for changing the gear ratio is to actuate a swash plate of the pump by oil-hydraulic pressure. For flexible and accurate control, a full-electric control technique attracts much attention [3]-[5]. In this paper, a simulation model of a HST system was built using a simulation tool software AMESim [6], considering oil-hydraulic components. Especially, pump dynamics were verified by experiment. Control of motor speed was investigated in the case of feedback control and two degree of freedom control.

Q20. Active Vibration Control of Excavator Working Equipment with ADAMS

Nowadays, construction machinery manufacturers tend to develop products with low vibration, low noise and low exhaust air pollution. However, by the recent trend of high performances at bearing and efficiency, the boom structures of construction machinery tend to be larger and heavier than the current type. Such design policy causes instability in the entire body, and especially causes boom vibration in the low frequency below 10 Hz, which are very harmful to the operator. Hence, this vibration has had to be reduced substantially. Very troublesome it is to control this vibration by any passive techniques to cater for the design requirement of construction machinery, which demand products to be flexible, energy saving and long life. In such a situation, an active control system of boom vibration with the use of hydraulic servomechanism will certainly be a nice choice.
Hydraulic excavator is an entity coupling with mechanical and hydraulic systems, and the
vibration is related to working equipment’s attitude and environmental loads. In order to evaluate its vibration characteristic during design cycle, a visual prototype of hydraulic excavator should be built at first, which includes hydraulic system and mechanical system. However, the conventional simulation software cannot combine hydraulic system with mechanical system ideally.
Furthermore, it is difficult to evaluate the loads acted on the whole system by manual also.
Therefore, it is arduous to obtain a perfect analysis results erenow. However, ADAMS software product, which is used extensively for the dynamic simulation of complex mechanical system, can be utilized to generate such an excavator prototype easily.

Q21. Asenov_en

The study of kinematic and dynamic parameters of manipulator of hydraulic excavator is based. The mechanism of this manipulator is plane multilinkage, that consists of arms joined and hydraulic cylinders.
The aim of this paper is to create methodology for kinematic and dynamic parameters research of working mechanism of hydraulic excavator.
We consider the working mechanism as conjunction of jib, arm and bucket, that are joined by the cylindrical joints and hydraulic cylinders. The working process is based on rotation of arm to jib with hydraulic cylinder.

Q22. autogearbox_Renault_Imagine

This article presents the modelling and simulation of the electro-hydraulic circuit of an automatic gearbox. The work concerns each component of the system: the electro-valve using a Pulse width modulated control, and different pressure reducers. The influence of the PWM on the pressure evolutions is simulated: the simulation of the global behaviour of the system is presented in the form of a quasi-static evolution of the controlled pressures as a ftmction of the PWM control. Another aspect of the study concems the modelling methodology used based on basic elements. The advantages of this polymorphic approach are emphasised.

Dynamic simulation of an electrohydraulic open center gas exchange valve actuator system for camless internal

Camless engines require independent gas-valve actuators which can provide accurate control, sufficient force, and require only a small percentage of engine output power. A valve actuation system concept with apparent advantages in these areas oyer existing systems is proposed. A potential design of required system components is presented and dynamic simulation included which make feasibility conclusions from the standpoint of performance, packaging, and power efficiency.
Trends toward downsized gas and diesel engines with high fuel efficiency and high specific power output f11lly warrant this research.
Based on consideration of valve actuation cycles and hydraulic power efficiency, an open-center hydraulic system schematic with series valves is the baseline of this project. Compact valve actuation and hydraulic spool-valve components were designed which would be suitable for typical engine layouts. With this potential design, hydraulic system simulation models were developed to predict the dynamic performance, power consumption, and tolerance to the temperature range of the application. Operating conditions and performance specifications were determined from technical paper references and consultations with Motorola engineers.

Q24. FinalReport%20V3%20May2005

Because there is a large demand for better fuel economy on vehicles, researching different hybrid methods is necessary. The main goal of this project was to design, build, and test a complete hydraulic launch assist system on a Ford F350 diesel truck. The system described in the report shows how each of the functional requirements was implemented using different modeling techniques and solutions. These included Excel modeling, developing a
complex control system, using DFMEA, and gathering test data. As shown in the report, the team met each functional requirement successfully according to their allotted guidelines. Large strides where made in making the system safe and reliability. In conclusion, this system proved the concept that makes a hydraulic hybrid vehicle safer, lighter, and smoother for marketability

Q25. flyer_appli_suspension_Letter

AMESim allows you to design and optimize suspension systems early in the process. It offers an open architecture for different technologies:
Passive, Semi-active and Active suspensions.
Mechanical, Hydraulic, Pneumatic, Electric and Magneto-Rheological suspensions.
System or components analysis.
A new step in understanding vibrations and controlling suspension systems has been made using AMESim, the most efficient tool to answer typical concerns such as time response of your actuators, stability analysis of pressure components, noise and vibrations in the hydraulic and pneumatic circuits, optimization of drivability and comfort abilities, off-line tests of control strategies, optimization of your network architecture, real time applications using physical models involving semi-automatic model simplification, development of new concepts with new technologies, increase of performances, prediction of temperatures influence, reduction of energy consumption, increase of efficiency…

Q26. gpc_2003

Accelerating Model Development for Hardware In the Loop Testing using Physical Models
A review of General Motors Powertrain’s experience with Opal-RT
and Imagine Software
What are the advantages of using AMESim over “controls”
modeling languages?
Can AMESim be used in real-time to model a transmission?
What type of hardware platform is required?
What is the overall cost?
Is the Technology Ready for rollout to users?

Q27. Hydraulic Hybrid Vehicle Project

Because there is a large demand for better fuel economy on vehicles, researching different hybrid methods is necessary. The main goal of this project was to design, build, and test a complete hydraulic launch assist system on a Ford F350 diesel truck. The system described in the report shows how each of the functional requirements was implemented usingdifferent modeling techniques and solutions. These included Excel modeling, developing a complex control system, using DFMEA, and gathering test data. As shown in the report, the
team met each functional requirement successfully according to their allotted guidelines. Large strides where made in making the system safe and reliability. In conclusion, this system proved the concept that makes a hydraulic hybrid vehicle safer, lighter, and smoother for marketability.

Q28. power_steering

The power steering unit [3] shown in Figure 1 consists in a steering wheel, a rotary valve, a rack, a hydraulic jack and lines. When the driver inputs a steering
angle command, the steering valve opens. This allows oil to flow into the hydraulic jack, with a pressure proportional to the amount of valve opening. The
oil pressure acts on the jack piston to create an actuating force proportional to the pressure. This actuating force then assists the driver in moving the jack piston and the mechanism connected to it (rack, tires…). The motion of the jack
piston is then feedback to the valve by the rack and pinion. The pinion rotation tends to close the valve, completing the control loop.

Q29. Simulation of hydraulic components for passenger cars

Contents
1. Introduction
2. Modelling and mathematical description of hydraulic systems
3. Integration algorithm with mass conservation
4. Component export for multidomain models
5. Active Tire Tilt Control-chassis system

Q30. Vector Tensor and basic equations of Fluid Mechanics

Product Description
This introductory text is geared toward engineers, physicists, and applied mathematicians at the advanced undergraduate and graduate levels. It applies the mathematics of Cartesian and general tensors to physical field theories and demonstrates them chiefly in terms of the theory of fluid mechanics. Numerous exercises appear throughout the text. 1962 edition.
Product Details
• Paperback: 320 pages
• Publisher: Dover Publications (January 1, 1990)
• Language: English
• ISBN-10: 0486661105
• ISBN-13: 978-0486661100

Q31. the simulation for a design process of a hydraulic circuit for automation gear boxes

The use of theory in a last resort, to analyse situations precisely and thus help in understanding phenomena, and as an aid to the design of Fluid Power systems, constitutes an approach promoted by the scientific community. This is becoming more and more a part of the design process of products developed by industrial companies. We can observe that this approach has developed in parallel with the evolution of numerical calculation algorithms and simulation software. The stages of development of the latter are also interesting to observe. At the start, these were useful general tools, or home produced tools.
From this point of view, users develop their models using a language, which is more or less adapted to mathematical model writing (general languages, Fortran or C). Later languages better adapted to simulation C SSL, VHDL- AMS [1], or graphic languages such as block diagrams or bond graphs were used. The idea of capitalising on models developed appeared more recently, giving rise to “specialist” software, making available to the user a component library. In the Fluid Power field, the typical library is made-up of standard hydraulic or pneumatic components. This approach only partially responds to the needs of users. From our point of view, the idea of integrating simulation into a more general process of training and aid to design has led us to develop a library of elementary ftmctions. This library partly inspired by bond graphs [2] [3], results from the analysis of existing fluid power systems from, which emanate a certain number of elementary ftmctions, which bring together scientific considerations and technological constraints representing the State of the Art in Fluid Power. The elementary functions thus identified do not aspire to being exhaustive. They rather represent the concept of a library, which is enriched and expanded by the diversity of its applications. It is also this diversity of applications, which ensures an irreplaceable feedback experience, which reinforces the quality and robustness of the library, which thus takes on the aspect, and dimensions of an industrial product. From this point of view, the role of simulation in the design process takes on a real sense involving two classes of actors in the company:
0 design specialists (research management and advanced studies) whose task is to finely analyse the systems under study and test different solutions,
0 the non design specialists whose role is more orientated towards cost reduction by evaluating, for example, the systems’ sensitivity and manufacturing tolerance.

 

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