Toward Safe and Human Friendly Hydraulics: The Passive Valve

2000 ◽  
Vol 122 (3) ◽  
pp. 402-409 ◽  
Author(s):  
Perry Y. Li
Keyword(s):  
Control Valve ◽  
Second Order ◽  
Hydraulic Systems ◽  
Power Sources ◽  
Directional Control ◽  
Physical Environments ◽  
Active Feedback ◽  
Valve Dynamics ◽  
Spool Valve ◽  
Port Device

Hydraulic systems, as power sources and transmissions, offer many advantages over electromechanical or purely mechanical counterparts in terms of power density, flexibility, and portability. Many hydraulic systems require touching and contacting the physical environments; and many of these systems are directly controlled by humans. If hydraulic systems are passive, they would be both safer to interact with, and easier for humans to control. In this paper, it is shown that a critical hydraulic component, the directional control valve, is not passive. However, the directional valve, as a one-port or a two-port device can become passive if appropriate spool valve dynamics are imposed. Methods to passify the valve for both first-order and second-order spool dynamics are considered. In the case of second-order spool dynamics, a passive method that relies on hardware modification, and an active feedback method, are proposed. [S0022-0434(00)01803-7]

EASY5 Model of Two Position Solenoid Operated Cartridge Valve

2002 ◽  
Author(s):  
Song Liu ◽  
Gary Krutz ◽  
Bin Yao
Keyword(s):  
Control Valve ◽  
Mathematic Model ◽  
Nonlinear Flow ◽  
Damping Force ◽  
Precise Control ◽  
Directional Control ◽  
Spring Force ◽  
Programmable Valve ◽  
Valve Dynamics ◽  
Nonlinear Performance

The two position solenoid operated cartridge valve is widely used in the applications, such as process control systems, pavers, agricultural machinery, where response and installed costs are more important than precise control through electronic position feedback. In recent years, the combination of multiple cartridge valves, so called ‘smart valve’ or ‘programmable valve’, which is able to break the mechanical linkage between the meter-in and meter-out orifices and enables high precision control as well as optimal usage of energy, is gaining engineering interests. But the control of such combination is far from trivial. It demands good knowledge of the valve dynamics and nonlinear flow properties. Unlike servo valve or proportional directional control valve, a mathematic model of solenoid operated cartridge valve, or even a thorough understanding of the dynamics and nonlinear performance, are not available. This paper presents an EASY 5 model for the two position solenoid operated cartridge valve. The model, which includes the solenoid force, spring force, damping force, flow force and nonlinear mass flow rate, can be used to analyze cartridge valve as well as simulate system or controller performance. It is also able to connect with Matlab for more complicated simulation.

CFD Analysis of Energy Loss of Direction Control Valve in Electro-Hydraulic Systems with Inverter

2014 ◽  
Vol 607 ◽  
pp. 393-396
Author(s):  
Aphaiwong Junchangpood
Keyword(s):  
Energy Loss ◽  
Transient Flow ◽  
Pressure Coefficient ◽  
Control Valve ◽  
Hydraulic Systems ◽  
Control Approach ◽  
Directional Control ◽  
Direction Control ◽  
Flow Pressure ◽  
Directional Control Valve

This paper presents a new approach for reducing energy consumption coupled with force and position controls in the electro-hydraulic systems (EHS). The EHS inverter will be added for control to vary the speed of electric motor driven hydraulic pump. In addition, a single directional control valve is used to control the system parameters, which cause loss of energy. The main objective of this research is to numerically analyze the energy loss in the new control approach in the EHS with the inverter by using a simple directional control valve. The spool displacements of 4/3 hydraulic closed center directional control valve, transient flow-pressure coefficient and energy loss were simulated with computational fluid dynamics (CFD). In addition, this paper presents CFD results. The relationships of flow rate variables with time-dependent pressure drop and energy loss were addressed. The flow behaviors related with transient flow-pressure coefficients were also discussed. It is found that the loss of energy increases, depending on both the large opening spool displacement and the inlet flow variable.

Exponential Tracking Control of a Hydraulic Proportional Directional Valve and Cylinder via Integrator Backstepping

2002 ◽  
Author(s):  
J. Chen ◽  
W. E. Dixon ◽  
J. R. Wagner ◽  
D. M. Dawson
Keyword(s):  
Pressure Drop ◽  
Tracking Control ◽  
Mechanical Load ◽  
Control Valve ◽  
Transient Behavior ◽  
Transportation Systems ◽  
System Response ◽  
Hydraulic Systems ◽  
Control Valves ◽  
Directional Control

Hydraulic systems are widely used in manufacturing processes and transportation systems where energy intensive operations are performed and “machine” control is vital. A variety of flow control products exist including manual directional control valves, proportional directional control valves, and servo-valves. The selection of a control valve actuation strategy is dependent on the system response requirements, permissible pressure drop, and hardware cost. Although high bandwidth servo-valves offer fast response times, the higher expense, susceptibility to debris, and pressure drop may be prohibitive. Thus, the question exists whether the economical proportional directional control valve’s performance can be sufficiently enhanced using nonlinear control strategies to begin approaching that of servo-valves. In this paper, exponential tracking control of a hydraulic cylinder and proportional directional control valve, with spool position feedback, is achieved for precise positioning of a mechanical load. An analytical and empirical mathematical model is developed which describes the transient behavior of the integrated components. A nonlinear backstepping control algorithm is designed to accommodate inherent system nonlinearities.

Development of a New Generation of Independent Metering Valve Circuit for Hydraulic Boom Cylinder Control

2015 ◽  
Vol 9 (2) ◽  
pp. 143-152
Author(s):  
Mashruk Ahamad ◽  
◽  
Quang-Truong Dinh ◽  
Syed Abu Nahian ◽  
Kyoung-Kwan Ahn ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Control Valve ◽  
Hydraulic Systems ◽  
Large Power ◽  
Directional Control ◽  
Hydraulic Equipment ◽  
Pressure Compensation ◽  
Primary Focus ◽  
Spool Valves ◽  
New Generation

Recent research on hydraulic systems has mainly focused on energy saving. This is because the efficiency of hydraulic systems is very low even though they have large power-to-size ratios. In mobile hydraulic equipment, conventional hydraulic spool valves with pressure compensators have already been replaced by valve assemblies with four-valve independent metering with electronically controlled pressure compensation. The independent metering concept and microprocessor control have much more potential to save more energy than conventional proportional valve control because of the increased controllability of the system. The primary focus of this study is to reduce the number of Independent Metering Valves (IMV) by introducing one directional control valve. This new model offers two degrees of freedom, i.e., controlling velocity and pressure, just as in conventional IMVs. In the system described here, two of the three independent valves are active during metering. In this paper, the theory behind a new method of flow control based upon load feedback is presented for two of the five distinct metering modes, and its performance is investigated and compared to that of a conventional IMV configuration.

The Study of Temperature Control Hydraulic Sensor

2012 ◽  
Vol 468-471 ◽  
pp. 1266-1269
Author(s):  
Yan Jun Zhang ◽  
Zi Ming Kou ◽  
Gui Jun Gao ◽  
Jun Zhang
Keyword(s):  
Temperature Control ◽  
Hydraulic System ◽  
Control Valve ◽  
Elastic Force ◽  
Working Environment ◽  
Hydraulic Circuit ◽  
New Type ◽  
Spool Valve ◽  
Special Working

Abstract. To improve the automation degree in special working environment which contains explosive gas. We develop a new type of temperature control hydraulic sensor basically on theory and lots of experiments. As the temperature reaches about 85°C，the motion part of the inductor will stretch to a certain length, and then it will push the adjusting rod. Simultaneously，the adjusting rod will overcome the elastic force of the spring and compel the spool valve to deform, and finally the control valve port will be open, it allows the control oil of the hydraulic system to pass. At last it reaches our destination that we can make the control of hydraulic circuit be realized.

Electric Motors Coupled to Hydraulic Motors as Actuators for Hydraulic Hardware-in-the-Loop Simulation

2005 ◽  
Author(s):  
Scott Driscoll ◽  
James D. Huggins ◽  
Wayne J. Book
Keyword(s):  
Complete System ◽  
Control Valve ◽  
Operating Conditions ◽  
Flow Control Valve ◽  
Hardware In The Loop ◽  
Hydraulic Systems ◽  
Advantages And Disadvantages ◽  
Hydraulic Motors ◽  
Proportional Flow ◽  
Hil Simulation

Hardware-in-the-Loop (HIL) Simulation enables testing of an actual physical component of a system under a variety of conditions without the expense of full scale testing. In hydraulic systems, flows or pressures that interface with the component in question are controlled by a computer running a simulation designed to emulate a complete system under real operating conditions. Typically, servo valves are used as actuators to control the flows or pressures. This paper investigates the use of electric servo-motors coupled to hydraulic gear motors as alternative actuators, and discusses some of the advantages and disadvantages that motors have in comparison to valves. A demonstration HIL simulation involving a mobile proportional flow control valve attached to an emulated backhoe is described, and results are compared to data from a real backhoe.

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