Stabilization of Nonlinear Systems by Switched Lyapunov Function

2015 ◽  
Author(s):  
Andy Zelenak ◽  
Mitch Pryor
Keyword(s):  
Lyapunov Function ◽  
Coordinated Control ◽  
Order System ◽  
General Applicability ◽  
Control Effort ◽  
New Approach ◽  
Software Packages ◽  
Switched Lyapunov Function ◽  
Software And Hardware ◽  
Robotic Application

If a Lyapunov function is known, a dynamic system can be stabilized. However, computing a Lyapunov function is often challenging. This paper takes a new approach; it assumes a basic Lyapunov-like function then seeks to numerically diminish the Lyapunov value. If the control effort would have no effect at any iteration, the Lyapunov-like function is switched in an attempt to regain control. The method is tested on four simulated systems to give some perspective on its usefulness and limitations. A highly coupled 3rd order system demonstrates the approach’s general applicability and finally the coordinated control of 7 motors for a robotic application is considered. Details on the publicly available software packages for application agnostic software and hardware environments are also presented.

Control of Nonlinear Systems in Normal Form by Complementary Lyapunov Functions

2017 ◽  
Author(s):  
Andy Zelenak ◽  
Benito Fernández ◽  
Mitch Pryor
Keyword(s):  
Lyapunov Function ◽  
Normal Form ◽  
Lyapunov Functions ◽  
General Type ◽  
Order System ◽  
Time Varying ◽  
Control Lyapunov Function ◽  
New Approach ◽  
Complementary Function ◽  
Siso Systems

If a Lyapunov function is known, a dynamic system can be stabilized. However, the search for a Lyapunov function is often challenging. This paper takes a new approach to avoid such a search; it assumes a basic Control Lyapunov Function [CLF] then seeks to numerically diminish the value of the Lyapunov function. If a singularity arises during calculations with the default CLF, a complementary function is used. The complementary function eliminates a common cause of singularities with the default CLF. While many other algorithms from the literature use switched or time-varying CLF’s, the presented method is unique in that the CLF’s do not require prior calculation and the technique applies globally. The method is proven and demonstrated for SISO systems in normal form and then demonstrated on a higher-order system of a more general type.

Many-Objective Optimal Design of Sliding Mode Controls

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Yousef Sardahi ◽  
Jian-Qiao Sun
Keyword(s):  
Optimal Design ◽  
Pareto Front ◽  
Sliding Mode ◽  
Design Method ◽  
Tracking Error ◽  
Control Design ◽  
Processing Algorithm ◽  
Order System ◽  
Post Processing ◽  
Control Effort

This paper presents a many-objective optimal (MOO) control design of an adaptive and robust sliding mode control (SMC). A second-order system is used as an example to demonstrate the design method. The robustness of the closed-loop system in terms of stability and disturbance rejection are explicitly considered in the optimal design, in addition to the typical time-domain performance specifications such as the rise time, tracking error, and control effort. The genetic algorithm is used to solve for the many-objective optimization problem (MOOP). The optimal solutions known as the Pareto set and the corresponding objective functions known as the Pareto front are presented. To assist the decision-maker to choose from the solution set, we present a post-processing algorithm that operates on the Pareto front. Numerical simulations show that the proposed many-objective optimal control design and the post-processing algorithm are promising.

scholarly journals BioExcel Building Blocks, a software library for interoperable biomolecular simulation workflows

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Pau Andrio ◽  
Adam Hospital ◽  
Javier Conejero ◽  
Luis Jordá ◽  
Marc Del Pino ◽  
...  
Keyword(s):  
Building Blocks ◽  
Biological Processes ◽  
Software Management ◽  
Software Library ◽  
Management Tools ◽  
Software Packages ◽  
Biomolecular Simulations ◽  
Software And Hardware ◽  
A Chain ◽  
Workflow Orchestration

Abstract In the recent years, the improvement of software and hardware performance has made biomolecular simulations a mature tool for the study of biological processes. Simulation length and the size and complexity of the analyzed systems make simulations both complementary and compatible with other bioinformatics disciplines. However, the characteristics of the software packages used for simulation have prevented the adoption of the technologies accepted in other bioinformatics fields like automated deployment systems, workflow orchestration, or the use of software containers. We present here a comprehensive exercise to bring biomolecular simulations to the “bioinformatics way of working”. The exercise has led to the development of the BioExcel Building Blocks (BioBB) library. BioBB’s are built as Python wrappers to provide an interoperable architecture. BioBB’s have been integrated in a chain of usual software management tools to generate data ontologies, documentation, installation packages, software containers and ways of integration with workflow managers, that make them usable in most computational environments.

SECURITY MODEL WITH THE "TIMING" MECHANISM OF THE INFORMATION SECURITY SYSTEM

2020 ◽  
pp. 97-102
Author(s):  
Yu.V. POLYANSKAYA ◽  
◽  
A.V. MOROZOV ◽  
S.G. KRASNOV ◽  
◽  
...  
Keyword(s):  
System Performance ◽  
Time Interval ◽  
Security Model ◽  
Acceptable Risk ◽  
New Approach ◽  
Control Subsystem ◽  
System Integrity ◽  
Security Models ◽  
Software And Hardware ◽  
Main Components

The main point of the new approach to security should be the development of effective security models that are adequate to the current level of development of software and hardware, as well as the possibility of flexible security management depending on the requirements, acceptable risk and resource consumption. The task of the kernel integrity control subsystem is to ensure the security of the system during its operation and detect incorrect interference of system subjects in its operation. The system integrity control subsystems are based on two main components: static and dynamic. The frequency of the kernel integrity control subsystem actuation determines the time that the system will be in the "information leak" state in the event of a violation of the system integrity. There are two approaches to determining the time interval T: the first approach is characterized by minimizing the loss of system performance due to the presence of the kernel integrity control subsystem in the system, the second approach is characterized by the fact that it provides a higher level of security in case of possible losses of system performance.

scholarly journals Telescoping method and congruences for double sums

2017 ◽  
Vol 14 (01) ◽  
pp. 143-165 ◽  
Author(s):  
Yan-Ping Mu ◽  
Zhi-Wei Sun
Keyword(s):  
Mathematical Software ◽  
New Approach ◽  
Software Packages ◽  
Finite Sums ◽  
Telescoping Method

In recent years, Sun proposed several sophisticated conjectures on congruences for finite sums with terms involving combinatorial sequences such as central trinomial coefficients, Domb numbers and Franel numbers. These sums are double summations of hypergeometric terms. Using the telescoping method and certain mathematical software packages, we transform such a double summation into a single sum. With this new approach, we confirm several open conjectures of Sun.

Fractional Order Universal Adaptive Stabilizer for Fractional Order Systems

2009 ◽  
Author(s):  
Yan Li ◽  
YangQuan Chen
Keyword(s):  
Fractional Order ◽  
Order System ◽  
Adaptive Stabilization ◽  
Space System ◽  
Control Effort ◽  
Finite Control ◽  
State Space System ◽  
Adaptive Stabilizer ◽  
Fractional Controller ◽  
Order State

In this paper, the fractional order universal adaptive stabilization of fractional order SISO system is discussed. The fractional universal adaptive stabilizer is u(t) = −k(t)sgn{CB}y(t), where 0Dtβk(t) = ‖y(t)‖p, which guarantees the asymptotic stability of the equilibrium point of fractional order state space system with finite control effort. Moreover, the fractional order system with order α ∈ (0, 1/(1+p)) can be stabilized by the fractional controller but not for the integer order controller. Simulation results are provided as the proof of concepts.

scholarly journals Improving the Performance of Automatic Speech Recognition Using Blind Source Separation

2019 ◽  
Vol 8 (6) ◽  
pp. 1411-1415
Keyword(s):  
Speech Recognition ◽  
Source Separation ◽  
Recognition System ◽  
Speech Recognition System ◽  
New Approach ◽  
Scattering Transform ◽  
Computing Performance ◽  
Original Speech ◽  
Robotic Application ◽  
Non Negative Matrix Factorization

In real world applications, Speech recognition system have grown due its significance in various online and offline applications such as security, robotic application, speech translator etc. These systems are widely used now-a-days where acquisition of signal is performed using various instruments which causes noise, source mixing and other impurities which affects the performance of speech recognition system. In this work, issue of source mixing in original speech signal is addressed which causes performance degradation. In order to overcome this we propose a new approach which utilizes non-negative matrix factorization modelling. This method utilizes scattering transform by applying wavelet filter bank and pyramid scattering to estimate the source and minimization of unwanted signals. After estimation the signals or sources, source separation algorithm is implemented using optimization process based on the training and testing method. Proposed approach is compared with other existing method by computing performance measurement matrices which shows the better performance

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