Investigation of an Electrohydraulic Servovalve With Tuneable Return Pressure and Drain Orifice

1987 ◽  
Vol 109 (3) ◽  
pp. 276-285 ◽  
Author(s):  
S. LeQuoc ◽  
R. M. H. Cheng ◽  
A. Limaye
Keyword(s):  
Closed Loop ◽  
Design Procedure ◽  
High Gain ◽  
Velocity Versus ◽  
System Control ◽  
Closed Loop System ◽  
Test Rig ◽  
Step Method ◽  
Steady State Condition ◽  
Tuning Parameters

This paper describes a new concept of electrohydraulic servovalve where the novelty lies mainly in the fact that the return pressure and return orifice of the servovalve are tuneable and can be adjusted to satisfy the system control requirements. The actuator velocity characteristics of a hydraulic servomechanism operating under steady state condition is analysed through the use of dimensionless quantities. It is established that the proposed configuration exhibits a nonlinear actuator velocity versus servovalve opening relationship and at small servovalve opening, the system offers a higher actuator velocity. The closed loop system transient responses are also investigated by means of digital computer simulation. The results are experimentally verified on a test rig specifically designed for this purpose. It is observed that with the return pressure and return orifice properly tuned, one can achieve a high gain yet high damping servosystem. A design procedure is described which provides the designer with a step by step method for determining the tuning parameters in order to obtain a desired system performance.

scholarly journals Robust H∞ Loop Shaping Controller Synthesis for SISO Systems by Complex Modular Functions

2021 ◽  
Vol 26 (1) ◽  
pp. 21
Author(s):  
Ahmad Taher Azar ◽  
Fernando E. Serrano ◽  
Nashwa Ahmad Kamal
Keyword(s):  
Design Methodology ◽  
Closed Loop ◽  
Complex Analysis ◽  
Controller Design ◽  
Filter Design ◽  
Design Procedure ◽  
Elliptic Functions ◽  
Loop System ◽  
Closed Loop System ◽  
Loop Shaping

In this paper, a loop shaping controller design methodology for single input and a single output (SISO) system is proposed. The theoretical background for this approach is based on complex elliptic functions which allow a flexible design of a SISO controller considering that elliptic functions have a double periodicity. The gain and phase margins of the closed-loop system can be selected appropriately with this new loop shaping design procedure. The loop shaping design methodology consists of implementing suitable filters to obtain a desired frequency response of the closed-loop system by selecting appropriate poles and zeros by the Abel theorem that are fundamental in the theory of the elliptic functions. The elliptic function properties are implemented to facilitate the loop shaping controller design along with their fundamental background and contributions from the complex analysis that are very useful in the automatic control field. Finally, apart from the filter design, a PID controller loop shaping synthesis is proposed implementing a similar design procedure as the first part of this study.

Sliding Mode Control Laws Design by the ADAR Method with Subsequent Invariant Manifolds Aggregation

2019 ◽  
Vol 20 (8) ◽  
pp. 451-460 ◽  
Author(s):  
A. A. Kolesnikov ◽  
A. A. Kuz’menko
Keyword(s):  
Robust Control ◽  
Invariant Manifolds ◽  
Closed Loop ◽  
Sliding Mode ◽  
Design Procedure ◽  
Sliding Surface ◽  
Closed Loop System ◽  
External Disturbances ◽  
Control Laws ◽  
The Stability

Sliding mode control (SMC) laws are commonly used in engineering to make a system robust to parameters change, external disturbances and control object unmodeled dynamics. State-of-the-art capabilities of the theory of adaptive and robust control, the theory of fuzzy systems, artificial neural networks, etc., which are combined with SMC, couldn’t resolve current issues of SMC design: vector design and stability analysis of a closed-loop system with SMC are involved with considerable complexity. Generally the classical problem of SMC design consists in solving subtasks for transit an object from an arbitrary initial position onto the sliding surface while providing conditions for existence of a sliding mode at any point of the sliding surface as well as ensuring stable movement to the desired state. As a general rule these subtasks are solved separately. This article presents a methodology for SMC design based on successive aggregation of invariant manifolds by the procedure of method of Analytical Design of Aggregated Regulators (ADAR) from the synergetic control theory. The methodology allows design of robust control laws and simultaneous solution of classical subtasks of SMC design for nonlinear objects. It also simplifies the procedure for closed-loop system stability analyze: the stability conditions are made up of stability criterions for ADAR method functional equations and the stability criterions for the final decomposed system which dimension is substantially less than dimension of the initial system. Despite our paper presents only the scalar SMC design procedure in details, the ideas are also valid for vector design procedure: the main difference is in the number of invariant manifolds introduced at the first and following stages of the design procedure. The methodology is illustrated with design procedure examples for nonlinear engineering systems demonstrating the achievement of control goals: hitting to target invariants, insensitivity to emerging parametric and external disturbances.

Sensitivity Reduction of Constraint Forces and Position Control for Mechanical Descriptor Systems

1997 ◽  
Vol 119 (2) ◽  
pp. 286-289
Author(s):  
Dan-chi Jiang ◽  
Wei-Yong Yan ◽  
K. L. Teo
Keyword(s):  
State Feedback ◽  
Closed Loop ◽  
Position Control ◽  
Design Procedure ◽  
Descriptor Systems ◽  
Algebraic Riccati Equation ◽  
Systematic Design ◽  
Closed Loop System ◽  
Constraint Forces ◽  
Constrained System

This paper deals with the position and force control for mechanical systems with holonomic constraints. Our concern is the design of a feedback controller such that the closed-loop system has a satisfactory transient response and is less sensitive to various types of disturbances. Using an appropriate transformation, the constrained system is converted into an unconstrained system of lower order. Then, an H∞, control problem involving the reduced system is formulated. In the case of state feedback, a systematic design procedure for solving the problem is presented, where the key step is the solution of an algebraic Riccati equation. An example is given to illustrate the effectiveness of the proposed method.

PMSM Servo System Control Based on Disturbance Observer

2010 ◽  
Vol 44-47 ◽  
pp. 1090-1094
Author(s):  
Hua Wei Chai ◽  
Jin Yu Zhou ◽  
Wei Ping Zhang ◽  
Zhi Gang Li
Keyword(s):  
Disturbance Observer ◽  
High Speed ◽  
Closed Loop ◽  
Servo System ◽  
System Control ◽  
Strong Impact ◽  
Closed Loop System ◽  
Ac Servo System ◽  
Ac Servo ◽  
Speed Tracking

In order to realize high speed control of some ac servo system, aimed at all kinds of uncertain factors such as greatly changing moment and torque, and strong impact torque. Therefore, for gaining good speed tracking characteristics, adaptive disturbance observer is adopted to observe load torque disturbance and speed variation. Stability of closed loop system is guaranteed by design of control tractics to satisfy track control requests of rocket launcher servo system. Simulation results indicate that this method can ideally observe disturbance and reduce output of controller, thus control performance of the system is improved and is greatly meaningful.

Output feedback boundary control of a flexible marine riser system

2017 ◽  
Vol 24 (16) ◽  
pp. 3617-3630 ◽  
Author(s):  
Yu Liu ◽  
Fang Guo
Keyword(s):  
Boundary Control ◽  
Closed Loop ◽  
Vibration Suppression ◽  
High Gain ◽  
Loop System ◽  
System State ◽  
Marine Riser ◽  
Closed Loop System ◽  
Observer Error ◽  
System States

This paper is concerned with the design of boundary control for globally stabilizing a flexible marine riser system. The dynamics of the riser system are represented in the form of hybrid partial–ordinary differential equations. Firstly, when the system state available for feedback is unmeasurable, an observer backstepping method is employed to reconstruct the system state and then design the boundary control for vibration suppression of the riser system. Subsequently, for the case that the system states in the designed control law cannot be accurately obtained, the high-gain observers are utilized to estimate those unmeasurable system states. With the proposed control, the uniformly ultimately bounded stability of the closed-loop system is demonstrated by the use of Lyapunov’s synthetic method and the state observer error is converged exponentially to zero as time approaches to infinity. In addition, the disturbance observer is introduced to track external environmental disturbance. Finally, the control performance of the closed-loop system is validated by carrying out numerical simulation.

scholarly journals Global Finite-Time Output Feedback Stabilization for a Class of Uncertain Nonholonomic Systems

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Baojian Du ◽  
Fangzheng Gao ◽  
Fushun Yuan
Keyword(s):  
Output Feedback ◽  
Finite Time ◽  
Closed Loop ◽  
Output Feedback Control ◽  
Design Procedure ◽  
Nonholonomic Systems ◽  
Feedback Stabilization ◽  
Closed Loop System ◽  
Output Feedback Stabilization ◽  
Switching Control Strategy

This paper investigates the problem of global finite-time stabilization by output feedback for a class of nonholonomic systems in chained form with uncertainties. By using backstepping recursive technique and the homogeneous domination approach, a constructive design procedure for output feedback control is given. Together with a novel switching control strategy, the designed controller renders that the states of closed-loop system are regulated to zero in a finite time. A simulation example is provided to illustrate the effectiveness of the proposed approach.

The Application of Fractional Order Calculus in Closed-Loop System Control

2012 ◽  
Vol 442 ◽  
pp. 315-320
Author(s):  
Yun Fang Feng
Keyword(s):  
Closed Loop ◽  
Design Method ◽  
Open Loop ◽  
Loop System ◽  
System Control ◽  
Closed Loop System ◽  
Open Loop System ◽  
System Robustness ◽  
Fractional Controller ◽  
Frequency Phase

A design method of fractional controller has been developed to meet the five different specifications, including for the closed-loop system robustness. The specifications of cross frequency, phase to get financing ϕ meters and robustness and complete performance curve based on level off the stage of open loop system, ensure damping is worse reaction time of model uncertainty gain change.

scholarly journals Decentralised PI controller design based on dynamic interaction decoupling in the closed-loop behaviour of a flotation process

2021 ◽  
Vol 11 (6) ◽  
pp. 4865
Author(s):  
Nomzamo Tshemese-Mvandaba ◽  
R. Tzoneva ◽  
M. E. S. Mnguni
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
Design Procedure ◽  
Loop System ◽  
Closed Loop System ◽  
Flotation Process ◽  
Loop Control ◽  
Decoupling Method ◽  
Pi Controllers ◽  
Interconnected Model

An enhanced method for design of decenralised proportional integral (PI) controllers to control various variables of flotation columns is proposed. These columns are multivariable processes characterised by multiple interacting manipulated and controlled variables. The control of more than one variable is not an easy problem to solve as a change in a specific manipulated variable affects more than one controlled variable. Paper proposes an improved method for design of decentralized PI controllers through the introduction of decoupling of the interconnected model of the process. Decoupling the system model has proven to be an effective strategy to reduce the influence of the interactions in the closed-loop control and consistently to keep the system stable. The mathematical derivations and the algorithm of the design procedure are described in detail. The behaviour and performance of the closed-loop systems without and with the application of the decoupling method was investigated and compared through simulations in MATLAB/Simulink. The results show that the decouplers - based closed-loop system has better performance than the closed-loop system without decouplers. The highest improvement (2 to 50 times) is in the steady-state error and 1.2 to 7 times in the settling and rising time. Controllers can easily be implemented.

scholarly journals Implementation of non-isolated three-port converter through augmented time response

2021 ◽  
Vol 12 (2) ◽  
pp. 913
Author(s):  
Ramya Devasahayam ◽  
Godwin Immanuel D
Keyword(s):  
Steady State ◽  
Time Domain ◽  
Closed Loop ◽  
High Gain ◽  
Pi Controller ◽  
Time Response ◽  
Voltage Gain ◽  
Closed Loop System ◽  
Time Domain Response ◽  
Fast Responses

<p><span lang="EN-US">The work is concerning a multi-port dc-dc converter with improved time response and steady state output. Here the converter carries bare amount of switches for managing the power with mono inductance. The inductance and along with that the switched capacitance are pre owned to bring large voltage gain. This paper put forwarded an appropriate controller for the closed loop monitored high-gain converter with three ports. Higher is that the conversion rate. This converter is also a good interface between DC-source and load that aims to progressing time response with FLC and PI controller in the closed loop system. The converter with the PI controller and FLC is look over and the fast responses are compared with time domain specifications. The simulation outcome indicates that the FLC based converter brings most excellent time domain response.</span></p>

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