A nonlilear controller for ship autopilots

2012 ◽  
Vol 34 (3) ◽  
pp. 203-210
Author(s):  
Le Thanh Tung
Keyword(s):  
Lyapunov Stability Theory ◽  
Pole Placement ◽  
Model Parameters ◽  
Control Law ◽  
Closed Loop System ◽  
Ship Model ◽  
Optimal Theory ◽  
The Stability ◽  
Kinematical Parameters ◽  
Placement Technique

Conventional ship autopilots are designed based on a linear ship model using pole - placement technique or linear optimal theory.  However, in operation, the ship kinematical parameters can go out the linear  limits. In this paper, a nonlinear optimal control law based on aggregated  variables is presented. The criterion is chosen so that the dynamic  characteristics of object are included. The stability of the closed-loop  system is global according to the Lyapunov stability theory. The control law depends explicitly on ship model parameters, so that it is can be easily to  tune when the parameters change.

scholarly journals Damage Detection and Vibration Control of a Delaminated Smart Composite Plate

2000 ◽  
Vol 9 (1) ◽  
pp. 096369350000900 ◽  
Author(s):  
Aditi Chattopadhyay ◽  
Changho Nam ◽  
Youdan Kim
Keyword(s):  
Composite Plate ◽  
Closed Loop ◽  
Order Theory ◽  
Pole Placement ◽  
Transverse Shear Deformation ◽  
Mean Square ◽  
Smart Composite ◽  
Closed Loop System ◽  
Higher Order Theory ◽  
Placement Technique

In this paper, the effects of delamination on the dynamic characteristics of a composite plate are investigated. The refined higher order theory is used to model the smart composite plate in the presence of delaminations. The theory accurately captures the transverse shear deformation through the thickness, which is important in anisotropic composites, particularly in the presence of discrete actuators and sensors and delaminations. Next, the detection of delamination is investigated using the Root Mean Square (RMS) values of the response of the composite plate subject to disturbances. An active control system is designed to minimise the effect of delamination. The pole placement technique is applied to design the closed loop system by utilising piezoelectric actuators. Numerical results show that the RMS information can be used to estimate the location of the delamination. The controller designed makes the delaminated plate behave like a healthy plate model. The controller also reduces the magnitudes of RMS responses due to disturbance.

Impact Control in Hydraulic Actuators

2004 ◽  
Vol 127 (2) ◽  
pp. 197-205 ◽  
Author(s):  
P. Sekhavat ◽  
Q. Wu ◽  
N. Sepehri
Keyword(s):  
Lyapunov Stability Theory ◽  
Control Law ◽  
Asymptotic Convergence ◽  
Hydraulic Parameters ◽  
Hydraulic Actuators ◽  
Task Control ◽  
Nonsmooth Systems ◽  
Type Contact ◽  
The Stability ◽  
Short Transition

Every manipulator contact task that begins with a transition from free motion to constraint motion may exhibit impacts that could drive the system unstable. Stabilization of manipulators during this transition is, therefore, an important issue in contact task control design. This paper presents a discontinuous controller to regulate the transition mode in hydraulic actuators. The controller, upon sensing a nonzero force, positions the actuator at the location where the force was sensed, thus, exerting minimal force on a nonmoving environment. The scheme does not require force or velocity feedback as they are difficult to measure throughout the short transition phase. Also, no knowledge about the environment or hydraulic parameters is required for control action. Due to the discontinuity of the control law, the control system is nonsmooth. First, the existence, continuation and uniqueness of Filippov’s solution to the system are proven. Next, the extension of Lyapunov stability theory to nonsmooth systems is employed to guarantee the global asymptotic convergence of the entire system’s state towards the equilibrium point. Complete dynamic characteristics of hydraulic functions and Hertz-type contact model are included in the stability analysis. Experiments are conducted to verify the practicality and effectiveness of the proposed controller. They include actuator collisions with hard and soft environments and with various approach velocities.

scholarly journals Circular Formation Control of Multiagent Systems with Any Preset Phase Arrangement

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Lina Jin ◽  
Shuanghe Yu ◽  
Dongxu Ren
Keyword(s):  
Control Problem ◽  
Multiagent Systems ◽  
Formation Control ◽  
Closed Loop ◽  
Phase Distribution ◽  
The Other ◽  
Control Law ◽  
Closed Loop System ◽  
The Stability ◽  
Phase Arrangement

This paper deals with the circular formation control problem of multiagent systems for achieving any preset phase distribution. The control problem is decomposed into two parts: the first is to drive all the agents to a circle which either needs a target or not and the other is to arrange them in positions distributed on the circle according to the preset relative phases. The first part is solved by designing a circular motion control law to push the agents to approach a rotating transformed trajectory, and the other is settled using a phase-distributed protocol to decide the agents’ positioning on the circle, where the ring topology is adopted such that each agent can only sense the relative positions of its neighboring two agents that are immediately in front of or behind it. The stability of the closed-loop system is analyzed, and the performance of the proposed controller is verified through simulations.

Single Phase Variable Sampling Phase Locked Loop using Composite Observer

2016 ◽  
Vol 2 (1) ◽  
pp. 49
Author(s):  
K Arun ◽  
K Selvajyothi
Keyword(s):  
Sampling Period ◽  
Phase Locked Loop ◽  
Pole Placement ◽  
Phase Variable ◽  
Variable Sampling ◽  
Drift Frequency ◽  
Wide Range ◽  
Periodic Input ◽  
The Stability ◽  
Placement Technique

<p>An observer based variable sampling period phase locked loop is introduced for grid connected systems. The composite observer acts as an efficient estimator of the fundamental components from a periodic input signal rich in DC and harmonics. The observer gains are designed using pole placement technique, which inherently ensures the stability of this estimator.  Even under drift frequency, a constant number of samples (512) per cycle are maintained with the help of the numerically controlled oscillator. This makes the oscillator gain elements in the observer a constant and eliminates the trigonometric computation. This phase locked loop is found to be working in a wide range of frequency 40 – 70Hz. The performance of the proposed scheme is studied with a synthetic harmonic rich signal as well as validated by implementing the PLL in Cyclone IV FPGA with a real time grid voltage.</p>

Stable Nonlinear Control Allocation for Aircraft with Multiple Control Effectors

2011 ◽  
Vol 138-139 ◽  
pp. 404-409 ◽  
Author(s):  
Heng Li ◽  
Jin Yong Yu ◽  
You An Zhang
Keyword(s):  
Closed Loop ◽  
Dynamic Control ◽  
Lyapunov Stability Theory ◽  
Invariant Set ◽  
Control Law ◽  
Control Allocation ◽  
Nonlinear Controller ◽  
Closed Loop System ◽  
Multiple Control ◽  
Simulation Results

With respect to aircraft with redundant multiple control effectors, a nonlinear controller, which is composed of a virtual control law and a dynamic control allocation with position constraints of each effector, is designed. Based on Lyapunov stability theory and LaSalle invariant set theorem, asymptotic stabilities of upper control subsystem, dynamic control allocation subsystem and overall closed-loop system are proved respectively. Simulation results show the effectiveness of the proposed method.

GENERALIZED SYNCHRONIZATION OF NONIDENTICAL FRACTIONAL-ORDER CHAOTIC SYSTEMS

2013 ◽  
Vol 27 (30) ◽  
pp. 1350195 ◽  
Author(s):  
XING-YUAN WANG ◽  
ZUN-WEN HU ◽  
CHAO LUO
Keyword(s):  
Fractional Order ◽  
Chaotic Systems ◽  
Lorenz System ◽  
Pole Placement ◽  
Generalized Synchronization ◽  
Chen System ◽  
Hyperchaotic Lorenz System ◽  
The Stability ◽  
Synchronization Scheme ◽  
Placement Technique

In this paper, a chaotic synchronization scheme is proposed to achieve the generalized synchronization between two different fractional-order chaotic systems. Based on the stability theory of fractional-order systems and the pole placement technique, a controller is designed and theoretical proof is given. Two groups of examples are shown to verify the effectiveness of the proposed scheme, the first one is to realize the generalized synchronization between the fractional-order Chen system and the fractional-order Rössler system, the second one is between the fractional-order Lü system and the fractional-order hyperchaotic Lorenz system. The corresponding numerical simulations verify the effectiveness of the proposed scheme.

scholarly journals Operational Space Control of a Lightweight Robotic Arm Actuated by Shape Memory Alloy (SMA) Wires

2016 ◽  
Author(s):  
Serket Quintanar-Guzmán ◽  
Somasundar Kannan ◽  
Miguel A. Olivares-Mendez ◽  
Holger Voos
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Closed Loop ◽  
Loop System ◽  
Robotic Arm ◽  
Control Law ◽  
Closed Loop System ◽  
End Effector ◽  
Position Regulation ◽  
The Stability

This paper presents the design and control of a two link lightweight robotic arm using a couple of antagonistic Shape Memory Alloy (SMA) wires as actuators. A nonlinear robust control law for accurate positioning of the end effector of the two-link SMA based robotic arm is developed to handle the hysteresis behavior present in the system. The model presented consists of two subsystems: firstly the SMA wires model and secondly the dynamics of the robotic arm itself. The control objective is to position the robotic arm’s end effector in a given operational plane position. For this regulation problem a sliding mode control law is applied to the hysteretic system. Finally a Lyapunov analysis is applied to the closed-loop system demonstrating the stability of the system under given conditions. The simulation results demonstrate the accurate and fast response of the control law for position regulation. In addition, the stability of the closed-loop system can be corroborated.

Adaptive Control of Uncertain Gun Control System of Tank

2011 ◽  
Vol 88-89 ◽  
pp. 88-92 ◽  
Author(s):  
Lu Juan Shen ◽  
Ye Bao ◽  
Jian Ping Cai
Keyword(s):  
Adaptive Control ◽  
Control System ◽  
Gun Control ◽  
Control Law ◽  
Uncertain Parameters ◽  
Simulation Studies ◽  
Closed Loop System ◽  
Control Scheme ◽  
The Stability ◽  
Adaptive Control Law

In this paper, a class of gun control system of tank is considered with uncertain parameters and the backlash-like hysteresis which modeled by a differential equation. An adaptive control law is designed with backstepping technique. Compared to exist results on tank gun control problem , in our control scheme, the effect of backlash hysteresis is considered completely than to be linearized simply and no knowledge is assumed on the uncertain parameters. the stability of closed loop system and the tracking performance can be guaranteed by this control law. Simulation studies show that this controller is effective.

scholarly journals Robust adaptive controller design for excavator arm

2019 ◽  
Vol 8 (4) ◽  
pp. 293
Author(s):  
Nga Thi-Thuy Vu
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
Lyapunov Stability Theory ◽  
Adaptive Controller ◽  
Closed Loop System ◽  
Model Free ◽  
Lagrange Form ◽  
Robust Adaptive ◽  
The Stability ◽  
Robust Adaptive Controller

This paper presents a robust adaptive controller that does not depend on the system parameters for an excavator arm. Firstly, the model of the excavator arm is demonstrated in the Euler-Lagrange form considering with overall excavator system. Next, a robust adaptive controller has been constructed from information of state error. In this paper, the stability of overall system is mathematically proven by using Lyapunov stability theory. Also, the proposed controller is model free then the closed loop system is not affected by disturbances and uncertainties. Finally, the simulation is executed in Matlab/Simulink for both presented scheme and the PD controller under some conditions to ensure that the proposed algorithm given the good performances for all cases.

PROJECTIVE SYNCHRONIZATION OF FRACTIONAL ORDER CHAOTIC SYSTEMS BASED ON STATE OBSERVER

2012 ◽  
Vol 26 (30) ◽  
pp. 1250176 ◽  
Author(s):  
XING-YUAN WANG ◽  
ZUN-WEN HU
Keyword(s):  
Fractional Order ◽  
Chaotic Systems ◽  
State Observer ◽  
Projective Synchronization ◽  
Pole Placement ◽  
Fractional Order Systems ◽  
Chen System ◽  
The Stability ◽  
Synchronization Scheme ◽  
Placement Technique

Based on the stability theory of fractional order systems and the pole placement technique, this paper designs a synchronization scheme with the state observer method and achieves the projective synchronization of a class of fractional order chaotic systems. Taking an example for the fractional order unified system by using this observer controller, and numerical simulations of fractional order Lorenz-like system, fractional order Lü system and fractional order Chen system are provided to demonstrate the effectiveness of the proposed scheme.

Sign in / Sign up

Export Citation Format

Share Document