scholarly journals Characterizing Sliding Surfaces of Cyber-Physical Systems

2020 ◽  
Vol 24 (3) ◽  
pp. 431-448
Author(s):  
Luc Jaulin ◽  
Fabrice Le Bars
Keyword(s):  
Control Algorithm ◽  
Closed Loop ◽  
Cyber Physical Systems ◽  
Cyber Physical System ◽  
Closed Loop System ◽  
Physical Systems ◽  
Set Membership ◽  
Different Types ◽  
Chattering Effect ◽  
Evolution Function

When implementing a non-continuous controller for a cyber-physical system, it may happen that the evolution function of the closed-loop system is not anymore piecewise continuous along the trajectory, mainly due to if statements inside the control algorithm. As a consequence, an unwanted chattering effect may occur. This behavior is often difficult to observe even in simulation. We propose here a set-membership method based on interval analysis to detect different types of discontinuities. One of them is the sliding surface where the state trajectory jumps indefinitely between two distinct behaviors. As an application, we consider the validation of a sailboat controller. We show that our approach is able to detect and explain some unwanted sliding effects that may be observed in rare and specific situations on our actual sailboat robots.

scholarly journals Categorical Semantics of Cyber-Physical Systems Theory

2021 ◽  
Vol 5 (3) ◽  
pp. 1-32
Author(s):  
Georgios Bakirtzis ◽  
Cody H. Fleming ◽  
Christina Vasilakopoulou
Keyword(s):  
System Architecture ◽  
Cyber Physical Systems ◽  
Cyber Physical System ◽  
System Behavior ◽  
Modeling And Analysis ◽  
Physical Systems ◽  
System Models ◽  
Computational Dynamics ◽  
Different Types ◽  
Categorical Semantics

Cyber-physical systems require the construction and management of various models to assure their correct, safe, and secure operation. These various models are necessary because of the coupled physical and computational dynamics present in cyber-physical systems. However, to date the different model views of cyber-physical systems are largely related informally, which raises issues with the degree of formal consistency between those various models of requirements, system behavior, and system architecture. We present a category-theoretic framework to make different types of composition explicit in the modeling and analysis of cyber-physical systems, which could assist in verifying the system as a whole. This compositional framework for cyber-physical systems gives rise to unified system models, where system behavior is hierarchically decomposed and related to a system architecture using the systems-as-algebras paradigm. As part of this paradigm, we show that an algebra of (safety) contracts generalizes over the state of the art, providing more uniform mathematical tools for constraining the behavior over a richer set of composite cyber-physical system models, which has the potential of minimizing or eliminating hazardous behavior.

Emerging Cyber-Physical Systems : An Overview

2018 ◽  
pp. 306-316
Author(s):  
Okolie S.O. ◽  
Kuyoro S.O. ◽  
Ohwo O. B
Keyword(s):  
Health Care ◽  
Economic Benefit ◽  
Physical World ◽  
Cyber Physical Systems ◽  
Cyber Physical System ◽  
Economic Sectors ◽  
Strategic Research ◽  
Physical Systems ◽  
Security Issues ◽  
Wide Range

Cyber-Physical Systems (CPS) will revolutionize how humans relate with the physical world around us. Many grand challenges await the economically vital domains of transportation, health-care, manufacturing, agriculture, energy, defence, aerospace and buildings. Exploration of these potentialities around space and time would create applications which would affect societal and economic benefit. This paper looks into the concept of emerging Cyber-Physical system, applications and security issues in sustaining development in various economic sectors; outlining a set of strategic Research and Development opportunities that should be accosted, so as to allow upgraded CPS to attain their potential and provide a wide range of societal advantages in the future.

A Digital Algorithm for Near-Minimum-Time Control of Robot Manipulators

1987 ◽  
Vol 109 (4) ◽  
pp. 320-327 ◽  
Author(s):  
C. K. Kao ◽  
A. Sinha ◽  
A. K. Mahalanabis
Keyword(s):  
Control Algorithm ◽  
State Feedback ◽  
Closed Loop ◽  
Robot Manipulator ◽  
Minimum Time ◽  
State Feedback Control ◽  
Final States ◽  
Closed Loop System ◽  
Time Control ◽  
Digital Algorithm

A digital state feedback control algorithm has been developed to obtain the near-minimum-time trajectory for the end-effector of a robot manipulator. In this algorithm, the poles of the linearized closed loop system are judiciously placed in the Z-plane to permit near-minimum-time response without violating the constraints on the actuator torques. The validity of this algorithm has been established using numerical simulations. A three-link manipulator is chosen for this purpose and the results are discussed for three different combinations of initial and final states.

scholarly journals OPEN-SCIENCE SPACE ISSUE: CALIBRATION OF MEASURING CHANNELS OF NON-DISMANTLING CYBER-PHYSICAL SYSTEMS

2021 ◽  
Vol 82 (3) ◽  
pp. 12-17
Author(s):  
Bohdan Stadnyk ◽  
◽  
Vasyl Yatsuk ◽  
Mykola Mykyjchuk ◽  
Svyatoslav Yatsyshyn ◽  
...  
Keyword(s):  
Physical System ◽  
Open Science ◽  
Cyber Physical Systems ◽  
Metrological Characteristics ◽  
Cyber Physical System ◽  
Cyberphysical Systems ◽  
Time Code ◽  
Efficient Operation ◽  
Physical Systems ◽  
Physical Quantities

The analysis of the concept of Open-Science Space is carried out. The existence of ways to achieve reproducibility and traceability of research results performed by a group of worldwide situated Cyber-physical system operators/supervisors is shown. Ways to ensure the efficient operation of Cyber-physical systems as complex technological nondemountable objects with high requirements for metrological characteristics have been studied. To develop the scattered cyberphysical systems, the portable stable-in-time code-controlled measures of physical quantities have been studied. They have to be metrologically confirmed in the laboratory before the delivery to the site of the measuring subsystem for its calibration.

Sensor and Actuator Intrusion Detection for Cyber-Physical Systems via Adaptive Estimation Algorithm

2020 ◽  
Author(s):  
Jiayi Su ◽  
Yuqin Weng ◽  
Susan C. Schneider ◽  
Edwin E. Yaz
Keyword(s):  
Kalman Filters ◽  
Adaptive Estimation ◽  
Estimation Algorithm ◽  
Cyber Physical Systems ◽  
Motor Speed ◽  
New Approach ◽  
Physical Systems ◽  
Unknown Type ◽  
Different Types ◽  
Conditional State

Abstract In this work, a new approach to detect sensor and actuator intrusion for Cyber-Physical Systems using a bank of Kalman filters is presented. The case where the unknown type of the intrusion signal is considered first, using two Kalman filters in a bank to provide the conditional state estimates, then the unknown type of intrusion signal can be detected properly via the adaptive estimation algorithm. The case where the target (either sensor or actuator) of the intrusion signal is unknown is also considered, using four Kalman filters in a bank designed to detect if the intrusion signal is about to affect healthy sensor or actuator signal. To test these methods, a DC motor speed control system subject to attack by different types of sensor and actuator signals is simulated. Simulations show that different types of sensor and actuator intrusion signals can be detected properly without the knowledge of the nature and the type of these signals.

Bayesian Model for Evaluating Real-World Adaptation Progress of a Cyber-Physical System

2021 ◽  
pp. 324-343
Author(s):  
Arif Sari ◽  
Joshua Chibuike Sopuru
Keyword(s):  
Work Environment ◽  
Real World ◽  
Environmental Conditions ◽  
Physical System ◽  
Bayesian Model ◽  
Cyber Physical Systems ◽  
Cyber Physical System ◽  
Industrial Activities ◽  
Physical Systems

Cyber-physical systems, also known as CPS, have come to stay. There is no doubt, CPS would one day outnumber humans in industries. How do we evaluate the adaptation progress of these systems considering changing environmental conditions? A failed implementation of a CPS can result to a loss. Since CPSs are designed to automate industrial activities, which are centred on the use of several technologies, collaboration with humans may sometimes be inevitable. CPSs are needed to automate several processes and thus help firms compete favourably within an industry. This chapter focuses on the adaptation of CPS in diverse work environment. Considering the ecosystem of the CPS, the authors present a Bayesian model evaluating the progress of adaptation of a CPS given some known conditions.

scholarly journals Reliability Analysis of Cyber–Physical Systems: Case of the Substation Based on the IEC 61850 Standard in China

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2589 ◽  
Author(s):  
Ye Cai ◽  
Yu Chen ◽  
Yong Li ◽  
Yijia Cao ◽  
Xiangjun Zeng
Keyword(s):  
Reliability Analysis ◽  
Power Loss ◽  
Cyber Physical Systems ◽  
Cascading Failure ◽  
Cyber Physical System ◽  
Analysis Method ◽  
Iec 61850 ◽  
Physical Systems ◽  
Communication Devices ◽  
Two Indices

With the increasing interaction between physical devices and communication components, the substation based on the IEC 61850 standard is a type of cyber–physical system. This paper proposes a reliability analysis method for substations with a cyber–physical interface matrix (CPIM). This method calculates the influences from both the physical device failures and the communication devices failures. Two indices, Probability of Load Curtailments and Expected Demand Not Supplied, are used in the reliability analysis. Given the simplified model of the practical substation based on the Chinese IEC 61850 standard, the results show that the substation system had a potential risk of cascading failure under the cyber–physical fusion trend, as the failure in cyber layer would increase the power loss of the whole system. The changing magnitude of Expected Demand Not Supplied increased significantly with increasing transmission delay rate of the process bus.

Sliding Mode Output Feedback Control of Vibration in a Flexible Structure

2007 ◽  
Vol 129 (6) ◽  
pp. 851-855 ◽  
Author(s):  
M. C. Pai ◽  
A. Sinha
Keyword(s):  
Output Feedback ◽  
Control Algorithm ◽  
Closed Loop ◽  
Sliding Mode ◽  
Output Feedback Control ◽  
Flexible Structure ◽  
Numerical Verification ◽  
Closed Loop System ◽  
New Approach ◽  
Small Gain

This paper presents a new approach for the robust control of vibration in a flexible structure in the presence of uncertain parameters and residual modes. The technique is based on the sliding mode control algorithm using direct output feedback and assumes that actuators and sensors are not collocated. The uncertainty matrix need not satisfy the invariance or matching conditions. The small gain theorem/μ analysis is applied to analyze the asymptotic behavior of the closed-loop system with parametric uncertainties inside boundary layers. The model of a flexible tetrahedral truss structure is used to conduct numerical verification of the theoretical analysis.

Sign in / Sign up

Export Citation Format

Share Document