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.

Transient Analysis of a High Pressure Seal Injection System Under Startup Conditions

2014 ◽  
Author(s):  
DeVon A. Washington ◽  
LeRoy N. Reiss
Keyword(s):  
Control Valve ◽  
Transient Behavior ◽  
Differential Pressure ◽  
Injection System ◽  
System Response ◽  
Primary Control ◽  
Fossil Plants ◽  
Actual System ◽  
Control Valves ◽  
In Series

This study examines the transient behavior of a seal injection system, for four boiler circulating water pumps, in an effort to optimize seal flush rates under startup conditions. During startup, seal injection supply water experiences a large increase in pressure, going from 1.8–26.2 MPa. This large increase in supply pressure presents a challenge in maintaining the desired differential pressure across the seals, and hence the optimum seal flush rate. Overshoot of the control valve position can result in starving the seals of seal water. Delayed responses expose the seals to excessively large differential pressures. The seal injection system was modeled using PIPENET™ Vision. The model consists of a detailed replica of the seal injection system pipe network. Initial and boundary conditions were obtained from plant DCS data and pump OEM specifications. A baseline model was developed and validated using actual system response data. Extended models considered two types of control systems, manual and differential pressure-control; as well as, control valves with various flow characteristics: linear and equal percentage. Additionally, a diffuser breakdown assembly and startup control valve were also introduced as control components into the model. Results show that the implantation of a diffuser breakdown assembly in series with the primary control valve (modified linear), in conjunction with automated controls produced a differential pressure of 436 kPa which was within the OEM specified range of differential pressures (345–690 kPa). A startup control valve used in series with the primary control valve also produced acceptable results (388 kPa). The proper design and operation of seal injection systems is vital to extending time between overhauls, thereby reducing maintenance costs. The use of the aforementioned control components in series with control valves is common for boiler feedwater regulation systems during startup; however, this is the first application known to the authors for pump seal injection systems in fossil plants. The results of the hydraulic simulation outlined in this study show this application is viable.

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.

Performance Analysis of Directional Control Valve: An Overview

2014 ◽  
Vol 592-594 ◽  
pp. 1983-1987
Author(s):  
Ramashankar Paswan ◽  
Jayanta Das ◽  
N. Kumar ◽  
Ajit Kumar ◽  
Santosh Kumar Mishra ◽  
...  
Keyword(s):  
Control Valve ◽  
Open Loop ◽  
Compressed Air ◽  
Hydraulic Control ◽  
Control Valves ◽  
Directional Control ◽  
Full State ◽  
Full State Feedback ◽  
High Bandwidth ◽  
Valve Control

Directional control valves start, stop or change the direction of flow in compressed air applications. To understand the different applications of compressed air and how valves are used, one must first have knowledge of the kinds and types of valves used by industries. This paper studies local valve control of the electro-hydraulic system. The slow response of hydraulic control valve usually becomes the hold-up of whole system performance. Although fast valves (e.g. high-bandwidth servo-valves) are available, they are far more expensive than slow valves (e.g. proportional directional control valves). To improve the performance of proportional directional control valves, three different types of controllers are synthesized. Firstly, based on the pole zero cancellation technique, an open loop compensator is designed which requires the accurate valve dynamic model information; Secondly, a full state feedback adaptive robust controller (ARC) is synthesized, which effectively takes into account the effect of parametric uncertainties and uncertain nonlinearities such as friction force and flow force. Finally, an output feedback ARC controller is synthesized to address the problem of un measurable states. Keywords: valve, hydraulic device, Simulink.

Pressure Control of the Proportional Directional Control Valve Test Rig Based on the Fuzzy Proportional-Integral-Double-Integral Controller

2017 ◽  
Author(s):  
Wenzhuo Shi ◽  
Jianhua Wei ◽  
Jinhui Fang ◽  
Mingjie Li ◽  
Qiang Zhang ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Performance Test ◽  
Control Valve ◽  
Pressure Control ◽  
Flow Control Valve ◽  
Test Rig ◽  
Double Integral ◽  
Relief Valve ◽  
Proportional Integral ◽  
Directional Control

The pressure drop needs to be kept constant in the flow rate/input signal performance test of proportional directional control (PDC) valve. In general, the control of valve pressure drop is implemented by regulating the relief valve or flow control valve that located between port A and port B of the PDC valve. But in this study, the load of the test valve is fixed and the stable pressure drop is obtained by changing the proportional relief valve which is placed in the inlet of the PDC valve. Then the mathematical model of the test rig and several controllers are established based on this idea. To be specific, proportional-integral (P-I) controller, proportional-integral-double-integral (P-I-II) controller, and fuzzy proportional-integral-double-integral (FP-I-II) controller are all applied to stabilize the pressure drop in this study. And the FP-I-II controller with compensation (FP-I-II-WC) is proved to be the best for this work both in the simulation and the actual experiment.

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]

Performance Improvement of Proportional Directional Control Valves: Methods and Experiments

2000 ◽  
Author(s):  
Fanping Bu ◽  
Bin Yao
Keyword(s):  
Control Valve ◽  
Open Loop ◽  
Parametric Uncertainties ◽  
Hydraulic Control ◽  
Tracking Accuracy ◽  
Control Valves ◽  
Output Tracking ◽  
Directional Control ◽  
Full State Feedback ◽  
High Bandwidth

Abstract This paper studies local valve control of the electro-hydraulic system. The sluggish response of hydraulic control valve usually becomes the bottleneck of whole system performance. Although fast valves (e.g. high-bandwidth servo-valves) are available, they are far more expensive than slow valves (e.g. proportional directional control valves). To improve the performance of proportional directional control valves, three different types of controllers are synthesized. Firstly, based on the pole zero cancellation technique, an open loop compensator is designed which requires the accurate valve dynamic model information; Secondly, a full state feedback adaptive robust controller (ARC) is synthesized, which effectively takes into account the effect of parametric uncertainties and uncertain nonlinearities such as friction force and flow force. Finally, an output feedback ARC controller is synthesized to address the problem of unmeasurable states. Theoretically, the proposed ARC controllers guarantee a prescribed output tracking transient performance and final tracking accuracy while achieving asymptotic output tracking in the presence of parametric uncertainties. Comparative experimental results are obtained to show the advantages and limitations of each method.

Model-Based Control of a Pressure-Compensated Directional Valve With Significant Dead-Zone

2019 ◽  
Author(s):  
Santeri Lampinen ◽  
Janne Koivumäki ◽  
Jouni Mattila ◽  
Jouni Niemi
Keyword(s):  
Control Method ◽  
Dead Zone ◽  
Open Loop ◽  
Mobile Manipulators ◽  
Hydraulic Systems ◽  
Loop Control ◽  
Model Based Control ◽  
Control Valves ◽  
Model Based ◽  
Directional Control

Abstract Hydraulic systems on mobile manipulators and industrial systems often come equipped with pressure-compensated proportional directional control valves with significant dead-zone. These kind of hydraulic valves are well suited for open-loop applications with an operator in control. However, designing closed-loop control for such systems is a challenging task. In this study, we propose a model-based control method for such valves to increase the performance of the current state-of-the-art in industrial robotic manipulator control. The proposed control method rigorously addresses the dynamics of a hydraulic manipulator system with dead-zone compensation for pressure-compensated directional control valves. The proposed method is evaluated with experiments on a commercial heavy-duty breaker boom with Sauer-Danfoss PVG 120 valves. The experimental results show accurate control of the manipulator despite the used slow-response load sensing valves.

scholarly journals CFD Simulation of a Post-Compensated Load Sensing Directional Control Valve

2021 ◽  
Vol 312 ◽  
pp. 05002
Author(s):  
Paola Fresia ◽  
Massimo Rundo
Keyword(s):  
Pressure Drop ◽  
Cfd Simulation ◽  
Control Valve ◽  
Design Tool ◽  
Lumped Parameter Model ◽  
Cfd Model ◽  
Load Sensing ◽  
Directional Control ◽  
Lumped Parameter ◽  
Directional Control Valve

The paper presents the CFD model of a load sensing directional control valve. The model was validated experimentally in terms of pressure drop and flow force at different positions of the spool. The spool position was imposed manually by means of a micrometric screw and a load cell was used for measuring the flow force. The CFD model was developed with the CAD-embedded tool FloEFD®. The model has been proved to be very reliable in estimating the pressure drop, moreover quite good results were obtained also in the evaluation of the flow force. The CFD simulations were used to tune the coefficients of a lumped parameter model of the valve, so that such a model can be efficiently used for the simulation of an entire hydraulic circuit. Moreover, the CFD model has been used as design tool for attenuating the detrimental effect of the flow force. In particular, the width of the land upstream of the metering edge has an influence on the resultant force on the spool. If was found that it is possible to significantly reduce the flow force at maximum opening with a relatively small increment of the pressure drop across the valve.

scholarly journals Research of stability of Load-sensing hydraulic drive operation, on the base of multimode directional control valve

2021 ◽  
Vol 12 (2) ◽  
pp. 93-99
Author(s):  
Oleksandr Petrov ◽  
◽  
Leonid Kozlov ◽  
Natalia Semichastnova ◽  
Olha Zavalniuk ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Energy Efficient ◽  
Hydraulic Drive ◽  
Control Valve ◽  
Design Parameters ◽  
Hydraulic Motor ◽  
Load Sensing ◽  
Directional Control ◽  
The Stability ◽  
Directional Control Valve

The article describes a new scheme of a hydraulic drive, which, thanks to the original design of a multimode directional control valve, has energy-efficient properties that are characteristic of load-sensing hydraulic drives. The proposed design of the multimode directional control valve ensures the operation of the hydraulic drive in four modes – unloading the hydraulic pump, regulating the flow of the hydraulic motor, the maximum flow of the hydraulic motor and protection against overload. In each of these modes, the hydraulic drive operates with low power losses due to the presence of a constant balancing pressure drop. This value is formed by a combination of design parameters of the directional control valve. The proposed value of the value of the balancing pressure drop of 0,7-0,8 MPa provides high energy efficiency of the hydraulic drive in the most critical operating mode – regulation of the hydraulic motor flow. In order to ensure the stability of the energy-efficient operation of the hydraulic drive in this mode, a research was made of the stability of transient processes with various combinations of design parameters of the overflow valve of the hydraulic control valve, as well as changes in the operating conditions of the hydraulic drive. As a result of theoretical researches, on the basis of mathematical modeling of working processes, combinations of design parameters of the hydraulic lock and the spool of the overflow valve were identified, which ensure the stability of the hydraulic drive in the mode of regulating the flow of the hydraulic motor. In particular, these are such parameters as the stiffness of the springs of the hydraulic lock and the overflow valve, the diameter and angle of inclination of the edge of the overflow valve spool, the area of the radial holes and the auxiliary choke of the overflow valve. It was also determined that in this mode, the stability of the hydraulic drive will be ensured under conditions of a load pressure of up to 20 MPa, a hydraulic motor flow rate of 100 l / min and a working fluid temperature of 80 °C.

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.

Sign in / Sign up

Export Citation Format

Share Document