Browse Topic: Electrohydraulics

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Nonlinear Iterative Optimization Process for Multichannel Remote Parameter Control10-03-03-001510/14/2019
In this article, compared with traditional Remote Parameter Control (RPC), the iterative process is improved based on linear transfer function (TF) estimation of the nonlinear dynamic system. In the improved RPC, the iteration coefficient is designed according to the convergence condition of the nonlinear iterative process, so that the convergence level, convergence speed, and iteration stability could be improved. The difference between the traditional and the improved RPC iterative process is discussed, the RPC iterative process of the nonlinear system is analyzed, and channel decoupling for Multi-Input Multi-Output (MIMO) system based on eigen-decomposition of the system TF and linear TF estimation is introduced. It assumes that the eigenvector matrix of the system TF remains the same, and the linear TF in the iterative process is estimated and updated, which is used for iterative calculation. The method for iteration coefficient is designed according to the nonlinear system convergence condition of the iterative process. The whole theory is verified on a two-channel electrohydraulic servo system and a lightweight motorcycle. The optimization strategy can be used not only for motorcycles but also for general dynamic systems with the same number of inputs and outputs. The experiment results show that the improved RPC is superior to the traditional RPC in the convergence level, convergence speed, and iteration stability. The improved algorithm makes the iterative process more effective, faster, and more stable. In the practical application of RPC, the results can be reproduced better, as well as the time and manpower can be saved.
Li, Meng, Zhang, Yong
A Steer-by-Wire System that Enables Remote and Autonomous Operation2014-01-24049/30/2014
Original equipment manufacturers and their customers are demanding more efficient, lighter, smaller, safer, and smarter systems across the entire product line. In the realm of automotive, agricultural, construction, and earth-moving equipment industries, an additional highly desired feature that has been steadily trending is the capability to offer remote and autonomous operation. With the previous requirements in mind, the authors have proposed and validated a new electrohydraulic steering technology that offers energy efficiency improvement, increased productivity, enhanced safety, and adaptability to operating conditions. In this paper, the authors investigate the new steering technology's capacity to support remote operation and demonstrate it on a compact wheel loader, which can be remotely controlled without an operator present behind the steering wheel. This result establishes the new steer-by-wire technology's capability to enable full autonomous operation as well.
Daher, Naseem A., Ivantysynova, Monika
SAE Off-Highway Engineering 2010-10-2810OFHD102810/28/2010
Making the leap from remanufacturing to new manufacturing Next-generation straddle carrier has intelligent controls, electrohydraulic braking.
Sauer-Danfoss - Managing tomorrow's big challenges with today's limited resources10OFHD0803_108/3/2010
Executive Viewpoints-Vehicle Development Insights from Industry: Driving Factors for Future Innovation. While dealing with the unpleasant results of the last year, engineering teams also undoubtedly looked toward the future-most specifically, at new regulations that are in place or on the near horizon. New EU functional safety standards, the advent of Tier 4 in the U.S. and Stage IV in Europe, and the continuing end-user demands of a better operator experience are all compelling events that must be addressed. On top of (or perhaps in spite of) these new regulations, customers demand these machines more quickly than ever, and OEM senior management teams require machines that differentiate themselves in the market. Even through these tough times, Sauer-Danfoss has been working as part of our customers' development teams to take on these big challenges. Despite the downturn, our test lab and research work has continued. We've taken a vehicle-by-vehicle approach to expand our applications and vehicle systems knowledge, tackling these new regulations while maintaining efficiency and total vehicle performance. Our goal is to deliver system solutions and flexible products that greatly reduce the engineering effort required by our customers to meet these challenges. We are doing this by designing products that simplify system integration, validating standard system design solutions in our test labs, and developing standardized control software solutions that allow engineers to improve both systems performance and operator experience.
Weston, Marc
My electronic crystal ball is full of hydraulic fluidOFHAUG09_068/1/2009
Executive Viewpoints-Vehicle Development Insights from Industry: Off-Highway 2020 and Beyond-My electronic crystal ball is full of hydraulic fluid. Being asked to look a decade into the future is really a daunting challenge. But being intimately associated with leading-edge hydraulic and electronic technologies as the President of Eaton's Hydraulics Group, I can tell you a couple of things right now with absolute certainty. One, I don't have a clue as to what to expect in 10 years.
VanArsdale, William
SAE Off-Highway Engineering 2009-02-01OFHFEB092/1/2009
Whistle down the wire Collaboration between OEMs and suppliers leads to new advances, and challenges, for electrohydraulic system control. Chipping away at drivetrain challenges Chips, sensors, controllers, software all combine to help engineers improve efficiency. Engineering disciplines unite Design tools help disparate groups provide input throughout the development process. Innovative thinking 101 West Virginia University professor Dr. James E. Smith issues a call for innovation as one of the central themes of his term as SAE's 2009 President.
SAE Off-Highway Engineering 2008-12-01OFHDEC0812/1/2008
Electrohydraulic engineers embrace integration Software improvements help both engineers and operators as architectures evolve. Indestructible from the start OEMs and suppliers are investing in testing equipment, facilities, and software to ensure proper performance of components prior to being placed in the field. To 2010 and beyond Engineers working on emissions-control systems for heavy-duty engines already are preparing for ever more stringent regulations later next decade. Top Technologies of 2008 The editors look back at some of the most significant technological innovations during the past year according to readers.
SAE Off-Highway Engineering 2005-10-01OFHOCT0510/1/2005
Hybrids go heavy The payoff for hybrid technology is high for vehicles with hefty payloads. A new era for electrohydraulics More components are designed with electronics in mind. Heavy-duty testing gets SWIFT Wheel-force transducers are helping to provide data-measurement capability faster and more economically than ever before. Operators hail cab upgrades Improving efficiency is new design target.
Hydraulic mattersOFHAPR05_034/1/2005
There is much potential for gain for everyone if OEMs and suppliers work together early in terms of hydraulic system design. Modern off-highway equipment is some of the most powerful, most productive, most impressive machinery ever built. The key to that success is fluid power. It seems, in fact, that the primary function of equipment is to deliver fluid power to the site so that buckets and blades can do their work. As such, it is imperative that OEMs work closely with fluid-power-component manufacturers, no matter how big the OEM, or how vast its knowledge of fluid power.
Ries, Richard
SAE Off-Highway Engineering 2002-10-01OFHOCT0210/1/2002
Including electrohydraulics As electrohydraulics technologies mature and expand, the cost of incorporating them into equipment continues to decrease. Operating the machine As long as people need to be in a machine to run a machine, operator stations will continue to become more operator-friendly.
SAE Off-Highway Engineering 2001-10-01OFHOCT0110/1/2001
More with less through electronic components Off-highway engineers have had to walk a precarious path in recent years by developing engine technologies that offer customers better vehicle performance and regulators lower emissions. The promises and problems of electrohydraulics Engineers acknowledge that electrohydraulics are the way of the future for the off-highway industry, and that the field itself could use a good public-relations campaign to attract more engineering students. Deere goes all out for agriculture To some, it may seem odd that John Deere picked this particular economy to launch over 50 new products, the most in its 164-year history. To others it reeks of confidence. Switching control in hydraulic drives Researchers from Johannes Kepler University believe agricultural machinery can be improved by further advances in motion generation.
Simulation of an Electrohydraulic Hitch Control System on an Agricultural Tractor8708184/1/1987
The tremendous pressures on the agricultural economy are forcing the use of electronic controls on agricultural equipment for greater operational efficiency. One of the first significant electronic controls on an agricultural tractor is for automatic actuation of the three-point hitch. This paper discusses the use of simulation in the development of such an electronic hitch control system.
Olson, David J., Cornell, Charles R.
Intelligent Servo Control as Trade-Up Technology8611979/1/1986
While advanced electrohydraulic control devices have been used in aerospace, defense and the upper segment of commercial applications for many years, this technology has not been available for broader commercial applications. The result is that most industrial applications are limited to the use of on/off-type valves that severely restrict the degree of control and precision. Increasingly, commercial applications need greater modulation in their control functions and intelligent servo control, using microchip technology, can provide an option as a trade-up technology.
McCormick, Joseph F.
Constant Speed Electrohydraulic Drive Mechanism for a Green Pea Harvester8611969/1/1986
The threshing mechanism of a Green Pea harvester is described with the drives previously used compared to a constant speed drive consisting of a variable displacement pump with electrohydraulic controls driving a fixed displacement motor. The electrohydraulic controls include an electrical displacement control device with its signal provided by a closed loop feedback controller. The advantage of the constant speed drive is a higher quality product harvested and improved harvesting flexibility.
Sanderson, Douglas G.
New Possibilities with the Electronic Control of Proportional Valves8411529/1/1984
As electrical remote controlled proportional valves become more and more popular on the mobile market we will see an increase in the possibilities of performing functional tasks through electronic channels rather than with mechanical - hydraulic methods. Danfoss has taken an active share in this field by starting the development of a range of electronic “black boxes” for the mobile market. These are for use with the Danfoss electrohydraulic proportional valve. The following new products will be discussed (function, application and advantages for the end-user): - Electronic flow adjustment unit - Electronic memory function - Electronic speed control
Hansen, J. C.
Electrohydraulic System Response - Nonlinear vs Linear8313289/12/1983
The results from an investigation of some of the effects of using a linearized model for prediction of the behavior of a nonlinear system are presented. The system studied is a velocity system using an electrohydraulic servoactuator to drive an inertial load. Both nonlinear and linearized system models are defined. The result of defining optimal feedback values for an integral quadratic performance index is shown along with the effect of choice of nominal operating point on the linearized system transient response. Finally, linear and nonlinear transient responses are compared for a range of step amplitudes.
Lance, G. M., Kleaveland, A. T.
Variability Analysis of Precision Mechanical Devices6406171/1/1964
An analytical method has been developed for estimating variability in the performance of a precision mechanical device that arises from variability of its internal parameters. This parameter variability is due both to initial in-tolerance variations and to subsequent environmental and time-dependent effects. A mathematical model of the device is formulated to define the relationships between individual parameters and various performance characteristics. This model is then manipulated on either an analog or a digital computer to permit calculation of partial derivatives of performance characteristics with respect to internal parameters. These partials are used in evaluating the Propagation of Variance formula, a mathematical statement that relates performance variance (an index of variability) to parameter variances (which must be known) and to the partial derivatives. This analytical approach is called the Moment method because it makes use of the mean and variance, the first two moments of the parameter value frequency distributions. The output of this type of analysis is extremely useful to the designer, for it tells him directly which parameters are most critical in determining the performance of the device, and it guides him in making necessary design modifications to reduce variability in performance. The Moment method is illustrated by application to the variability analysis of a two-stage electrohydraulic servo valve.
Mesloh, R. E., Mark, D. G.
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