Browse Topic: Hydraulic drives

Items (39)

Redundancy Control of Anti-lock Braking System Based on Electro-hydraulic Braking System

09/13/2022

As the basic function of the active safety configuration of a vehicle, the anti-lock braking system will compromise the driving safety if it fails. Based on the self-designed electro-hydraulic braking system, this article proposes an anti-lock brake redundant control architecture. The electro-hydraulic braking system is mainly composed of four parts: a brake pedal unit, a hydraulic drive unit, a brake execution unit, and a control unit. The mechanical structure is compact and exquisite, and the system has the function of precise and adjustable hydraulic pressure. The control architecture adopts a hierarchical control design, which is mainly composed of an upper wheel slip rate controller and a lower hydraulic pressure controller. Both the upper and lower controllers use a sliding mode variable structure control to improve the robustness and accuracy of the control. The upper slip rate controller outputs the desired master cylinder hydraulic pressure with the optimum slip rate of the

Liu, Yiping, Pei, Xiaofei, Guo, Xuexun

Testing of Oxygen Equipment

ARP1398A (Current)

08/11/2021

This ARP delineates requirements for system cleanliness, test gas supply system, test stand design, environmental chamber definition, instrumentation, dynamic test equipment and testing procedures.

A-10 Aircraft Oxygen Equipment Committee

Design Approach and Dimensionless Analysis of a Differential Driving Hydraulic Free Piston Engine

2016-01-8091

09/27/2016

A new method for driving the hydraulic free piston engine is proposed. This method achieves the compression stroke automatically rather than special recovery system. Principle of hydraulic differential drive free-piston engine is analyzed and the control strategy of this novel hydraulic driving engine is also introduced. Then energy balance method is used to design the main parameters of the novel engine. High pressure and secondary high pressure of the hydraulic system are constrained by the combustion parameters and therefore parameters are analyzed. In order to verify the effectiveness of energy balance method, the mathematical model is established based on the piston force analysis and engine working principle. The transient results of dynamics are obtained through simulation. In addition, the effectiveness of the simulation is proofed by dimensionless analysis. It indicates that energy balance method realizes the basic performance of hydraulic free piston engine.

Zhang, Shuanlu, Zhao, ZhenFeng, Zhao, Changlu, Zhang, Fujun, Liu, Yuhang

Modeling and Analyzing for Hydraulic-Driven Cooling System of Heavy Duty Truck

2016-01-0222

04/05/2016

The heavy duty trucks have large engine power and drive continuously in mountainous area, so the heat dissipation of engine is very important. In the traditional cooling system with fixed transmission ratio fan, the cooling capacity is insufficient and the engine is easy to be over-heated when the engine is working in low speed and heavy load conditions. Owning to the bigger size of electric motor compared to the hydraulic motor, it is not suitably applied to the heavy duty trucks. Contrasted with the electric motor, the hydraulic drive cooling system is widely applied in heavy duty trucks due to smaller size, larger power, continuous speed modulation and flexible installation location. However, the low transmission efficiency of the pump-motor system results in high power consumption of the cooling system. In this paper, the mathematical and simulation model of hydraulic-driven fan cooling system is established for the specific engine. The study applies the digital PID controller of

Zhang, Xingyu, Yang, Bo, Tan, Gangfeng, Mei, Binyu, Li, Zhilei, Yang, Zhongjie, Wang, Can

The Study on Co-Simulation Based Tracked Vehicle Path Tracking Control

2015-01-1114

04/14/2015

The tracked vehicle with a fully hydraulic driving system, which has a strong traveling performance of passing and mobility ability in the complex terrain, is a typical system of mechanical-electrical-hydraulic integration. At the same time, for the good low-speed stability of the hydraulic system, this vehicle is widely applied in most engineering projects. However, for the complexity and unpredictability of the motion state in the complex environment and the power matching of the driving system, the driving path of the tracked vehicle with hydraulic driving is difficult to control. Moreover, for the complicated interaction between mechanics, the establishment of the mathematical model is much more complex, and the traditional mechanics-control and hydraulic-control co-simulation can not accurately simulate this physical phenomenon. The kinematic and dynamics characteristics of the tracked vehicle are studied firstly, and the dynamics model is built. Meanwhile, the hydraulic system is

Wang, Can, Yang, Bo, Tan, Gangfeng, Wang, YiRui, Zhou, Li

Simulation Study of Hydraulic Differential Drive Free-piston Engine

2015-01-1300

04/14/2015

The hydraulic free piston engine is a complex mechanical-electro-liquid system, in order to simplify the complex system of the single hydraulic free piston engine, a new method for the driving of hydraulic free piston engine is proposed. Hydraulic differential drive achieves the compression stroke automatically rather than special recovery system. The structure and principle of hydraulic differential drive free-piston engine are analyzed and the mathematical model is established based on the piston force analysis and the hydraulic system working principle. In addition, the control strategy of this novel hydraulic driving engine is also introduced. Finally, the transient results of dynamics are obtained through simulation. Then we compare our results to the ones from the hydraulic free piston engine made by the company Innas. The results show that: 1) the simplified engine can achieve the similar performance of the Innas BV concept. 2) The maximum frequency and the maximum power of the

Zhang, Shuanlu, Zhao, Changlu, Zhao, ZhenFeng, Yafei, Dong, Ma, Fukang

Bosch Rexroth

13OFHD0613_1306/13/2013

Manufacturing and logistical excellence Companies serving the off-highway industry face an array of challenges in the current global marketplace. While some regions are experiencing growth and demand for new equipment, other regions continue to face economic headwinds. In addition, technology challenges and regulatory events such as Tier 4 Final make it necessary for companies to be as flexible and responsive as they can to changing market needs. Manufacturers will often promote new technologies or product updates as the “right way” to solve these challenges. However, product innovation must go hand-in-hand with manufacturing and logistical excellence-because no matter how innovative a product is, it must be manufactured efficiently with the highest quality, and be delivered through flexible, efficient supply chains to achieve success. New product technology may help drive the industry, but manufacturing and logistical excellence make up the engine under the hood.

Bracht, Berend

Aerospace Pressurization System Design

AIR1168/7A (Current)07/25/2011

The pressurization system design considerations presented in this AIR deal with human physiological requirements, characteristics of pressurization air sources, methods of controlling cabin pressure, cabin leakage control, leakage calculation methods, and methods of emergency cabin pressure release.

AC-9 Aircraft Environmental Systems Committee

Regenerative hydraulics

OFHOCT06_0410/01/2006

The use of multiple hydraulic pumps can satisfy the needs of various circuits in off-highway equipment. With fuel prices continually on the rise, it is critical to maximize the operating efficiency of off-highway equipment. Southwest Research Institute (SwRI) continues to develop advanced electrohydraulic systems that improve vehicle efficiency. New efforts are focusing on improving the efficiency of the powertrain, the hydraulic systems, and the engine accessories that all consume significant energy during vehicle operation. Motive power is produced by powertrains to ascend grades, overcome rolling resistance, pull plows, push blades, or move harvesters through fields. Powertrain efficiency improvement is being pursued through continuously variable transmissions (CVTs), including hydraulic CVTs, to produce the maximum desired travel speed while minimizing the fuel consumed by the engine.

Stecklein, Gary

Teeth Clearance Effects Upon Pressure and Film Thickness in a Trochoidal Hydrostatic Gear Pump

21-218-G4-24708/01/2004

This paper describes the teeth clearance influence on the tooth number contact in a hydrostatic pump in which arc circular profiles are used. Both the teeth clearance and the teeth deformation in contact are considered. Because of the teeth clearance, a severe reduction in number point contact and diminution in wide surface contact of the pinion are predicted. A steep-by- steep procedure for determining the normal force contact between teeth is outlined. The pressure contact and the film thickness are then deduced. Comparisons with the result obtained for the pump without clearance are made. Despite the appearance, the benefit of the high geometrical conformity, which normally leads to low pressure and a thick film, is strongly altered.

Paffoni, B., Progri, R., Gras, R.

Aerospace Pressurization System Design

AIR1168/7 (Historical)06/22/2004

AC-9 Aircraft Environmental Systems Committee

Hydraulics for economics

OFHOCT03_0210/01/2003

The design of a digitally controlled hydraulic fan drive from Denison Hydraulics is said to help diesel engines run leaner and cleaner. One of the keys to properly and efficiently controlling emissions from diesel powered on- and off-highway machinery is maintaining the engine's optimum operating temperature. That fact plus a very important secondary benefit, reducing fuel usage, can be achieved by using an infinitely variable hydraulic fan drive. A recent solution to reducing emissions, adapted by a majority of engine suppliers to both the on- and off-highway market, has been the introduction of an electronic gas-recirculation (EGR) system. While relatively effective at reducing emissions, the EGR solution also causes considerable parasitic power loss on the engine, resulting in higher fuel consumption. As an on-highway example, an EGR system adds $5000 to $7000 per Class-8 truck application. These costs include such items as variable geometry turbochargers, additional intercoolers

Travel Performance and Rating Procedure, Crawler Mounted Hydraulic Excavators, Material Handlers, Knuckle Boom Log Loaders, and Certain Forestry Equipment

J1309_200304 (Historical)

04/24/2003

This SAE Standard describes a uniform method to calculate and specify travel performance characteristics of hydraulic excavators, material handlers, knuckle boom log loaders, delimbers, feller bunchers, harvesters, processors, and other knuckle boom material handlers. It establishes definitions and specifies machine conditions for calculations and tests. This document applies to crawler mounted machines such as hydraulic excavators as defined in SAE J/ISO 6165 and ISO 7135, and knuckle boom log loaders as defined in SAE J1209 and SAE J2055. This document also applies to certain forestry equipment defined in SAE J1209 and ISO 6814 that have crawler mountings such as delimbers, feller bunchers, harvesters, and processors. Included in the definition of hydraulic excavators are also front shovel, clamshell, and telescoping boom excavators.

MTC C5, Excavators

Switching controls in hydraulic drives

OFHOCT01_0410/01/2001

Researchers from Johannes Kepler University believe agricultural machinery can be improved by further advances in motion generation. Proper adjustment of plow geometry is a challenging handling operation for the operator of plowing and hay-harvesting machines. The optimal values depend on the actual ground situation, which may vary. To adapt the parameters to the ground optimally, adjustment is necessary rather frequently, which realistically can be done only via remote control, or, even better, with automatic control. Current practice is to adjust manually by spindles and to use some complex kinematic mechanism to get an uncoupled relation between the position of the spindles and the relevant functional plow parameters. With full automatic control, easier operation and optimal results-both with respect to quality and performance-can be achieved. The mechanical performance characteristics of modern hay harvesters and tractors allow operation speeds of about 30 km/h (18.6 mph). At such

Switching Type Control of Hydraulic Drives - a Promising Perspective for Advanced Actuation in Agricultural Machinery

2000-01-255909/11/2000

Further advances in agricultural machinery require - amongst others - means for fast and precise positioning. Hydraulic drives fit very well to the environmental conditions of this machinery and can provide the required performance. State of the art methods of fluid power control by servo or proportional valve technology are not adequate for cost and maintenance reasons. Switching techniques are an alternative. Various concepts of switching exist. Some of these also show good efficiency. To put these techniques to practice requires very fast switching valves which currently are not available. One promising concept to realize such valves is outlined.

Scheidl, R., Garstenauer, M., Manhartsgruber, B.

Symbols for Hydrodynamic Drives

J640_200003 (Historical)

03/10/2000

The following system of symbols is recommended for use in technical papers and engineering reports dealing with hydrodynamic drives.

Automatic Transmission and Transaxle Committee

DESCRIPTION OF ACTUATION SYSTEMS FOR AIRCRAFT WITH FLY-BY-WIRE FLIGHT CONTROL SYSTEMS

AIR4253 (Historical)

05/01/1999

This AIR provides a description of representative state-of-the-art, fly-by-wire (FBW) actuation systems used in flight control systems of manned aircraft. It presents the basic characteristics, hardware descriptions, redundancy concepts, functional schematics, and discussions of the servo controls, failure monitoring, and fault tolerance. All existing FBW actuation systems are not described herein; however, those most representing the latest designs are included. While this AIR is intended as a reference source of information for future aircraft actuation system designs, the exclusion or omission of any other appropriate actuation system or subsystem should not limit consideration of their use on future aircraft.

A-6A3 Flight Control and Vehicle Management Systems Cmt

Swing Performance And Rating Procedure, Material Handlers, Knuckle Boom Log Loaders And Certain Forestry Equipment

J2393_199806 (Historical)

06/01/1998

This SAE Standard describes a uniform method to calculate and specify swing performance characteristics of material handlers, knuckle boom log loaders, delimbers, feller bunchers, harvesters, processors, and other knuckle boom material handlers. It establishes definitions and specifies machine conditions for calculations and tests. This document applies to knuckle boom log loaders as defined in SAE J1209 and SAE J2055 and to certain forestry equipment defined in SAE J1209 and ISO 6814 that have rotating upper-structures such as feller bunchers, harvesters, processors, and forwarders. Included in the definition of knuckle boom log loaders are behind the cab and rear-mounted log loaders not having their own power supply.

MTC4, Forestry and Logging Equipment

Hydraulic Drive Systems and Potential Use for Automobiles and Airplanes

97558110/01/1997

Utilization of hydrostatic drives for power transmission, along with hydropneumatic accumulator energy storage can provide significant opportunities for improvements in vehicle design. These advantages are particularly relevant when considering advanced concept vehicles such as flying automobiles. Research and development in this technology has primarily focused on the fuel economy improvements that can be achieved in automobiles using a hydrostatic transmission and hydropneumatic accumulator energy storage. The accumulator permits the engine power to be uncoupled from the road load, thus enabling the engine to be operated at a more efficient point. By using wheel drive units that can operate as either motors (when driving) or pumps (when braking), regenerative braking can also be achieved, with the energy stored in the accumulator. In addition to improved fuel economy, several other significant design opportunities can be exploited. The drivetrain concept that has been most

Fronczak, Frank J., Holmes, Bruce J., Beachley, Norman H.

Robust Control of Hydraulic Servos

96179508/01/1996

Developing controllers for hydraulic servos is difficult due to the inherent uncertainty and nonlinear characteristics of the system. Systems are classed as uncertain when they are subject to unknown parameter variations or disturbances, or when there is incomplete knowledge of the system model, all of which are common in hydraulic servo systems. However, unlike conventional control techniques, the use of modern control methods means that system uncertainty can be considered at the controller design stage, and consequently robust controllers can be developed. In this paper the robust control of hydraulic servo systems is considered, and sources of uncertainty typical in hydraulic drives are discussed. The effect of ignoring these uncertainties is demonstrated by simulation experiments of a hydraulic servo, comparing conventional control techniques to the modern approach of H∞ optimal control. The implementation of modern controllers is also discussed.

Hampson, S. P., Chawdhry, P. K., Burrows, C. R.

TRAVEL PERFORMANCE AND RATING PROCEDURE, CRAWLER MOUNTED HYDRAULIC EXCAVATORS, MATERIAL HANDLERS, KNUCKLE BOOM LOG LOADERS, AND CERTAIN FORESTRY EQUIPMENT

J1309_199606 (Historical)

06/01/1996

This SAE Standard describes a uniform method to calculate and specify travel performance characteristics of hydraulic excavators, material handlers, knuckle boom log loaders, delimbers, feller bunchers, harvesters, processors, and other knuckle boom material handlers. It establishes definitions and specifies machine conditions for calculations and tests. This document applies to crawler mounted machines such as hydraulic excavators as defined in SAE J1057 and ISO 7135, and knuckle boom log loaders as defined in SAE J1209 and SAE J2055. This document also applies to certain forestry equipment defined in SAE J1209 and ISO 6814 that have crawler mountings such as delimbers, feller bunchers, harvesters, and processors. Included in the definition of hydraulic excavators are also front shovel, clamshell, and telescoping boom excavators.

MTC C5, Excavators

Charles M. Manly: An Early American Innovator in Aircraft Engines

95050302/01/1995

During an exemplary engineering career Charles Matthews Manly (1876-1927), former president of the SAE and one of America's foremost aircraft engine pioneers, contributed greatly to the design and development of the radial piston engine, which came to dominate aircraft propulsion until the 1950s. He is best known for development and refinement of a world-class 52-hp, five-cylinder, water-cooled radial aircraft engine at the Smithsonian Institution. His early academic achievements led to his appointment as chief assistant to Professor S. P. Langley, secretary of the Smithsonian Institution, who was engaged in early aeronautic experiments and, in 1903, racing with the Wright brothers to demonstrate the first manned aeroplane. Easily the most advanced aeronautical engine in the world at the turn of the century, the so-called Manly-Balzer radial powerplant used in Langley's Aerodrome was almost 20 years ahead of its time in terms of specific-weight excellence. Manly risked his life twice

Rinek, Larry M.

AUXILIARY POWER SYSTEM CONSIDERATIONS FOR ADVANCED MILITARY AIRCRAFT

AIR1603 (Current)

06/01/1993

This document provides a brief description of the auxiliary power equipment that is available with enough description and pertinent comments to enable an engineer to make logical preliminary selection of the appropriate equipment for advanced military aircraft programs. The information has been kept as brief as possible to include the maximum amount of equipment in a relatively short document. It is not intended to replace textbook design analysis or detailed information available from the equipment suppliers. The document describes auxiliary power equipment. Auxiliary power is defined as follows: "Those elements of secondary power [defined as all aircraft nonpropulsive power generation and transmission] related to main engine bleed air and shaft power extraction or power generation separate from the main engines. Included are engine bleed air systems, remote engine driven gearboxes, engine starting systems, auxiliary power units, and emergency power systems." Additional definitions

AE-6 Starting Systems and Auxiliary Power Committee

Electrohydraulic Loadsensing

91181409/01/1991

Valve-controlled hydraulic drives are frequently used when high dynamics, high reliability and a compact structural form are required. A disadvantage which is frequently attributed to a valve-controlled drive is its poor running efficiency. It not only leads to higher energy consumption but - amongst other things - to the necessity of installing larger pumps and more elaborate cooling equipment. Both these factors cause an increase in the costs of hydraulic drives. Load sensing is known from the field of mobile hydraulics as a driving concept with high running efficiency. In load sensing the supply pressure is adjusted to suit the actuator's highest point of load pressure. The dynamics of this system is worse than that of systems with a constant supply pressure. Electrohydraulic load sensing offers possibilities to improve the dynamics of valve-controlled drives in load sensing by using control engineering measures.

Backé, W., Zãhe, B.

Crawler Mounted Hydraulic Excavator Travel Performance

J1309_199105 (Historical)

05/01/1991

This SAE Standard provides a uniform method for calculating and specifying travel performance characteristics of hydrostatically driven crawler mounted hydraulic excavators as defined in SAE J1057.

MTC C5, Excavators

Sealing of Pressurised Media in Automotive Applications for Rotating Shafts

86049002/01/1986

The rubber industry provides special oil seals from elastomeric materials to seal pressurised shaft applications. Normally these are small and simple looking devices, which can tolerate quite complex conditions. The design of the seal has a tremendous impact on good performance. Basic parameters for pressure oil seals made from elastomeric materials will presented. Application conditions must be balanced to the degree of seal stress. For example the right compromise has to be chosen for flexibility and stability of the lip section. The heat which is generated by friction must be dissipated through the shaft and the medium to be sealed. Medium and elastomeric material must not be overloaded thermally. The product of pressure and surface speed (p · v) is an important characteristic for the evaluation of how much a seal is stressed. A graph of achievable ‘p · v’-figures will be presented. In general pressure applications require closer attention to material selection than general purpose

Rapp, Hermann, Forch, Hans

Opportunities and Challenges for Electric-Drive Systems on Aircraft

84162710/01/1984

Traditionally, aircraft systems have relied upon bleed air from the main engine as the primary energy source for environmental control systems (ECS) and anti-icing systems. With the next generation of engines, bleed air may not be available to the extent utilized in the past. Electric drive systems are now being considered as viable alternatives for ECS. Electric drives are also being considered for traditional hydraulic drives in applications such as engine fuel pumps, and flap actuators. Several aspects of electric drive systems consisting of permanent-magnet motors (PMM's) and solid-state power electronics for the primary generation or secondary control of electric drives on aircraft are discussed in this paper. For power distribution, conventional 120/208-v, 3-phase, 400-Hz; 270-vdc, variable frequency/constant voltage, and variable frequency/variable voltage systems are the primary candidates. Specific examples on 270-vdc power generation, variable speed drives for an ECS

Beauchamp, Edward D.

CRAWLER MOUNTED HYDRAULIC EXCAVATOR TRAVEL PERFORMANCE

J1309_198303 (Historical)

03/01/1983

This recommended practice applies to hydraulic excavators as defined in SAE Standard J1057, which are crawler mounted. It describes the methods for calculating and specifying travel performance characteristics. It does not apply to wheel mounted excavators.

MTC C5, Excavators