A Linear Time Varying Model for On-Off Valve Controlled Pneumatic Actuators

1990 ◽  
Vol 112 (4) ◽  
pp. 740-747 ◽  
Author(s):  
C. Kunt ◽  
R. Singh
Keyword(s):  
Linear Time ◽  
Digital Simulation ◽  
Control Valve ◽  
Open Loop ◽  
Rotary Valve ◽  
Pneumatic Actuators ◽  
Linear Time Invariant ◽  
Directional Control ◽  
Actuation Systems ◽  
Time Invariant

A new linear time varing (LTV) model has been developed for open loop, on-off valve controlled pneumatic actuation systems. This formulation is based on a periodic profile description for variable operating points and directional control valve flow variations. The dynamic behavior of the example case, a single acting cylinder controlled by a two way-two port rotary valve, under the cyclic pressure loading is obtained using the proposed LTV model. Experimental evidence and digital simulation predictions based on the nonlinear mathematical equations validate the analytical formulation. The proposed LTV model is found to be better and more applicable than linear time invariant (LTI) models used previously by many investigators.

scholarly journals A dynamic model and performance analysis of a stepped rotary flow control valve

2019 ◽  
Vol 233 (9) ◽  
pp. 1195-1208 ◽  
Author(s):  
Karem Abuowda ◽  
Siamak Noroozi ◽  
Mihai Dupac ◽  
Phil Godfry
Keyword(s):  
Linear Time ◽  
Control Valve ◽  
Flow Control Valve ◽  
Main Concept ◽  
Linear Time Invariant ◽  
Dynamic Representation ◽  
Advanced Control ◽  
And Performance ◽  
Time Invariant ◽  
Rotary Type

The hydraulic independent metering is an advanced actuator driving technique that allows the implementation of advanced control algorithms or methods. The main concept of independent metering is to control hydraulic actuators ports, which are the meter-in and meter-out, separately. In this article, a novel stepped rotary type valve has been developed for embedding in hydraulic independent metering systems, instead of conventional types such as poppet and spool. The insertion leads to developing different and novel control techniques, which require software-in-the-loop simulation and hardware-in-the-loop simulation of the proposed system. The paper explores the dynamic representation of this valve and defines its own performance limitations. This includes the development of a linear model comprising its two main subparts which are the stepper motor and the rotary orifice. Consequently, the linear time-invariant methods are used to explore the performance of the valve by considering the effect of different parameters namely the pressure drop, friction coefficient, damping coefficient, and bristle coefficient.

scholarly journals Disturbance Observer-Based Offset-Free Global Tracking Control for Input-Constrained LTI Systems with DC/DC Buck Converter Applications

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4079
Author(s):  
Kyunghwan Choi ◽  
Dong Soo Kim ◽  
Seok-Kyoon Kim
Keyword(s):  
Tracking Control ◽  
Disturbance Observer ◽  
Linear Time ◽  
Estimation Error ◽  
Open Loop ◽  
Buck Converter ◽  
Invariance Property ◽  
Linear Time Invariant ◽  
Global Tracking ◽  
Time Invariant

This paper presents an offset-free global tracking control algorithm for the input-constrained plants modeled as controllable and open-loop strictly stable linear time invariant (LTI) systems. The contribution of this study is two-fold: First, a global tracking control law is devised in such a way that it not only leads to offset-free reference tracking but also handles the input constraints using the invariance property of a projection operator embedded in the proposed disturbance observer (DOB). Second, the offset-free tracking property is guaranteed against uncertainties caused by plant-model mismatch using the DOB’s integral action for the state estimation error. Simulation results are given in order to demonstrate the effectiveness of the proposed method by applying it to a DC/DC buck converter.

scholarly journals Dynamic behaviour of pneumatic actuators in open-loop controlled by proportional valves

2020 ◽  
Vol 180 ◽  
pp. 04012
Author(s):  
Valentin Nicolae Cococi ◽  
Carmen-Anca Safta ◽  
Constantin Călinoiu
Keyword(s):  
Control Valve ◽  
Open Loop ◽  
Pneumatic Actuator ◽  
Control Technique ◽  
Hydraulic Control ◽  
Pneumatic Actuators ◽  
Pneumatic Control ◽  
Directional Control ◽  
New Generation ◽  
Directional Control Valve

The development of proportional and servo-mechanisms hydraulic control technique offered the premises of the development of pneumatic control, too. Despite the disadvantages of the nonlinearities appeared in the pneumatic systems (air compressibility being one of the causes), the new generation of proportional equipment made it possible to have a good quality pneumatic control system in our days. The goal of the paper is to demonstrate, by using numerical simulation technique, that the proportional valves used in pneumatic actuator drives occur at a good system dynamic at a reasonable cost as against to the directional control valve as it usually used in pneumatic actuator drives.

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