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 Pinning Control Strategy of Multicommunity Structure Networks

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Chao Ding ◽  
Hong Yao ◽  
Jun Du ◽  
Xing-zhao Peng ◽  
Zhe Wang
Keyword(s):  
Community Structure ◽  
Control Strategy ◽  
Coupling Strength ◽  
Lyapunov Stability Theory ◽  
Pinning Control ◽  
Control Law ◽  
Structure Information ◽  
The Stability ◽  
Intensive Control ◽  
Better Than

In order to investigate the effects of community structure on synchronization, a pinning control strategy is researched in a class of complex networks with community structure in this paper. A feedback control law is designed based on the network community structure information. The stability condition is given and proved by using Lyapunov stability theory. Our research shows that as to community structure networks, there being a threshold hT≈5, when coupling strength bellows this threshold, the stronger coupling strength corresponds to higher synchronizability; vice versa, the stronger coupling strength brings lower synchronizability. In addition the synchronizability of overlapping and nonoverlapping community structure networks was simulated and analyzed; while the nodes were controlled randomly and intensively, the results show that intensive control strategy is better than the random one. The network will reach synchronization easily when the node with largest betweenness was controlled. Furthermore, four difference networks’ synchronizability, such as Barabási-Albert network, Watts-Strogatz network, Erdös-Rényi network, and community structure network, are simulated; the research shows that the community structure network is more easily synchronized under the same control strength.

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.

Asymptotic Force Control of Hydraulic Actuators With Friction: Theory and Experiments

2004 ◽  
Author(s):  
P. Sekhavat ◽  
N. Sepehri ◽  
Q. Wu
Keyword(s):  
Theoretical Analysis ◽  
Asymptotic Convergence ◽  
Solution Theory ◽  
Hydraulic Actuators ◽  
Nonsmooth Systems ◽  
Control Scheme ◽  
Valve Dynamics ◽  
Discontinuous Model ◽  
Solid Foundation ◽  
Theory And Experiments

This paper documents the development, theoretical analysis and experimental evaluation of a Lyapunov-based nonlinear control scheme for asymptotic force regulation of hydraulic actuators with friction. The complete discontinuous model of actuator friction, servo-valve dynamics, and nonlinear hydraulic functions are all included in the theoretical solution and stability analyses of the resulting nonsmooth system. The frictionless contact force is modeled as a linear stiffness. Filippov’s solution theory and the extension of LaSalle’s invariance principle to nonsmooth systems are employed to prove the asymptotic convergence of the system trajectories towards equilibria. Experiments complement the theoretical analysis in providing a solid foundation for implementation of the proposed control scheme for asymptotic force regulation of the hydraulic actuators despite friction effects.

A Design Method of LS-SVM Based Stable Adaptive Controller for a Class of Nonlinear Systems

2011 ◽  
Vol 48-49 ◽  
pp. 17-20
Author(s):  
Chun Li Xie ◽  
Tao Zhang ◽  
Dan Dan Zhao ◽  
Cheng Shao
Keyword(s):  
Nonlinear Systems ◽  
Design Method ◽  
Nonlinear Function ◽  
Lyapunov Stability Theory ◽  
Adaptive Controller ◽  
Control Law ◽  
Continuous Systems ◽  
Control Schemes ◽  
Closed Systems ◽  
Simulation Results

A design method of LS-SVM based stable adaptive controller is proposed for a class of nonlinear continuous systems with unknown nonlinear function in this paper. Due to the fact that the control law is derived based on the Lyapunov stability theory, the scheme can not only solve the tracking problem of this class of nonlinear systems, but also it can guarantee the asymptotic stability of the closed systems, which is superior to many LS-SVM based control schemes. The effectiveness of the proposed scheme is demonstrated by simulation results.

scholarly journals Adaptive Projective Synchronization between Two Different Fractional-Order Chaotic Systems with Fully Unknown Parameters

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
Liping Chen ◽  
Shanbi Wei ◽  
Yi Chai ◽  
Ranchao Wu
Keyword(s):  
Fractional Order ◽  
Chaotic Systems ◽  
Projective Synchronization ◽  
Control Law ◽  
Unknown Parameters ◽  
Chen System ◽  
Fractional Order Differential Equations ◽  
Response Systems ◽  
The Stability ◽  
Adaptive Control Law

Projective synchronization between two different fractional-order chaotic systems with fully unknown parameters for drive and response systems is investigated. On the basis of the stability theory of fractional-order differential equations, a suitable and effective adaptive control law and a parameter update rule for unknown parameters are designed, such that projective synchronization between the fractional-order chaotic Chen system and the fractional-order chaotic Lü system with unknown parameters is achieved. Theoretical analysis and numerical simulations are presented to demonstrate the validity and feasibility of the proposed method.

The stability of the positive solution for a fractional SIR model

2016 ◽  
Vol 10 (01) ◽  
pp. 1750014 ◽  
Author(s):  
Yingjia Guo
Keyword(s):  
Differential Equation ◽  
Positive Solution ◽  
Stability Theory ◽  
Lyapunov Stability Theory ◽  
Sir Model ◽  
Differentiable Functions ◽  
Classical Calculus ◽  
Global Positive Solution ◽  
Fractional Differential ◽  
The Stability

In order to deal with non-differentiable functions, a modification of the Riemann–Liouville definition is recently proposed which appears to provide a framework for a fractional calculus which is quite parallel with classical calculus. Based on these new results, we study on the fractional SIR model in this paper. First, we give the general solution of the fractional differential equation. And then a unique global positive solution of the SIR model is obtained. Furthermore, we get the Lyapunov stability theory. By using this stability theory, the asymptotic stability of the positive solution is analyzed.

Cooperative Tracking Control for Formation Keeping of Fractionated Spacecraft Based on Error Exchanging

2014 ◽  
Vol 1016 ◽  
pp. 649-654
Author(s):  
Ya Feng Niu ◽  
Yong Ming Gao
Keyword(s):  
Tracking Control ◽  
Cooperative Control ◽  
Sliding Mode ◽  
Control Law ◽  
Velocity Information ◽  
The Stability ◽  
Cooperative Tracking ◽  
Fractionated Spacecraft ◽  
High Degree ◽  
Formation Keeping

This paper discusses the cooperative control for formation keeping of fractionated spacecraft, which is a new concept in recent years. For system of second-order differential equations of formation flying dynamics, knowledge of graph and consensus theory is introduced in study. By means of the idea of sliding mode control, we design a tracking control law for time-varying desired signal. Via exchanging error information among modules, the control law can make errors synchronized up to zero to achieve tracking. Relative velocity information between modules is not needed in this control law, which will efficiently reduce the requirements for relative navigation between modules. Then we prove the stability of the control system. Finally numerical simulation results show the effectiveness of the control law. By configuring the control parameters reasonably, we can achieve high degree of control accuracy.

scholarly journals Hybrid Passivity Based and Fuzzy Type-2 Controller for Chaotic and Hyper-Chaotic Systems

2017 ◽  
Vol 11 (2) ◽  
pp. 96-103 ◽  
Author(s):  
Fernando Serrano ◽  
Josep M. Rossell
Keyword(s):  
Lyapunov Exponents ◽  
Chaotic System ◽  
Control Strategy ◽  
Chaotic Systems ◽  
Control Law ◽  
Four Dimensions ◽  
Design Requirements ◽  
The Stability ◽  
Theoretical Results

AbstractIn this paper a hybrid passivity based and fuzzy type-2 controller for chaotic and hyper-chaotic systems is presented. The proposed control strategy is an appropriate choice to be implemented for the stabilization of chaotic and hyper-chaotic systems due to the energy considerations of the passivity based controller and the flexibility and capability of the fuzzy type-2 controller to deal with uncertainties. As it is known, chaotic systems are those kinds of systems in which one of their Lyapunov exponents is real positive, and hyper-chaotic systems are those kinds of systems in which more than one Lyapunov exponents are real positive. In this article one chaotic Lorentz attractor and one four dimensions hyper-chaotic system are considered to be stabilized with the proposed control strategy. It is proved that both systems are stabilized by the passivity based and fuzzy type-2 controller, in which a control law is designed according to the energy considerations selecting an appropriate storage function to meet the passivity conditions. The fuzzy type-2 controller part is designed in order to behave as a state feedback controller, exploiting the flexibility and the capability to deal with uncertainties. This work begins with the stability analysis of the chaotic Lorentz attractor and a four dimensions hyper-chaotic system. The rest of the paper deals with the design of the proposed control strategy for both systems in order to design an appropriate controller that meets the design requirements. Finally, numerical simulations are done to corroborate the obtained theoretical results.

Robust Synchronization of Fractional-Order Arneodo Chaotic Systems Using a Fractional Sliding Mode Control Strategy

2018 ◽  
pp. 1-22
Author(s):  
Samir Ladaci ◽  
Karima Rabah ◽  
Mohamed Lashab
Keyword(s):  
Sliding Mode Control ◽  
Fractional Order ◽  
Chaotic Systems ◽  
Sliding Mode ◽  
Chaotic Behavior ◽  
Control Design ◽  
Lyapunov Stability Theory ◽  
Mode Control ◽  
Control Configuration ◽  
The Stability

This chapter investigates a new control design methodology for the synchronization of fractional-order Arneodo chaotic systems using a fractional-order sliding mode control configuration. This class of nonlinear fractional-order systems shows a chaotic behavior for a set of model parameters. The stability analysis of the proposed fractional-order sliding mode control law is performed by means of the Lyapunov stability theory. Simulation examples on fractional-order Arneodo chaotic systems synchronization are provided in presence of disturbances and noises. These results illustrate the effectiveness and robustness of this control design approach.

Function Projective Dual Synchronization with Uncertain Parameters of Hyperchaotic Systems

2017 ◽  
Vol 6 (4) ◽  
pp. 1-16 ◽  
Author(s):  
A. Almatroud Othman ◽  
M.S.M. Noorani ◽  
M. Mossa Al-sawalha
Keyword(s):  
Adaptive Control ◽  
Lyapunov Stability Theory ◽  
Control Law ◽  
Uncertain Parameters ◽  
Unknown Parameters ◽  
Chen System ◽  
Response Systems ◽  
Hyperchaotic Lu System ◽  
Hyperchaotic Systems ◽  
Adaptive Control Law

Function projective dual synchronization between two pairs of hyperchaotic systems with fully unknown parameters for drive and response systems is investigated. On the basis of the Lyapunov stability theory, a suitable and effective adaptive control law and parameters update rule for unknown parameters are designed, such that function projective dual synchronization between the hyperchaotic Chen system and the hyperchaotic Lü system with unknown parameters is achieved. Theoretical analysis and numerical simulations are presented to demonstrate the validity and feasibility of the proposed method.

Sign in / Sign up

Export Citation Format

Share Document