A Unified Approach for Independent Manipulator Joint Acceleration Control and Observation

2003 ◽  
Author(s):  
ElSayed M. ElBeheiry ◽  
Ahmed S. Zaki ◽  
Waguih H. ElMaraghy
Keyword(s):  
Variable Structure ◽  
Small Time ◽  
Observer Design ◽  
Unified Approach ◽  
Variable Structure Systems ◽  
Procedural Approach ◽  
Structure State ◽  
Bounded Disturbances ◽  
The Stability ◽  
Joint Acceleration

The ultimate goal of a manipulator control design is to combine the design of both the controller and the observer into one procedural approach. Hence, the stability of the global system, namely, the manipulator dynamics, controller, and observer is guaranteed. This paper presents a new, unified approach in combining the control and observation problem for robotic manipulators. It links the design of an independent joint acceleration controller to the design of a variable structure state observer that is used to estimate the joint acceleration. Since both the joint acceleration controller and the observer introduced in this paper are likely to implement high gains to improve tracking, the effects of the time delay between the measurement of the output and the control loop response has been investigated. The observer design also considers the observation robustness against unknown but bounded disturbances using the theory of variable structure systems. A simulation study to investigate the performance of the joint acceleration controller and observer is conducted on a PUMA 560 robot. Simulation results showed that the proposed combination of observer and controller are robust to the change in the payload and small time delays.

scholarly journals A Method for Assessing the Stability of Digital Automatic Control Systems (ACS) with Discrete Elements. Hypothesis and Simulation Results

2020 ◽  
Author(s):  
Vladimir Kodkin ◽  
Alexander Baldenkov ◽  
Alexander Anikin
Keyword(s):  
Automatic Control ◽  
Control Systems ◽  
Variable Structure ◽  
Sampling Interval ◽  
Discrete Elements ◽  
Digital Controllers ◽  
Variable Structure Systems ◽  
New Approach ◽  
Automatic Control Systems ◽  
The Stability

The article presents a new approach to the analysis of the stability of automatic systems with discrete links.In almost all modern automatic control systems, there are links that break signals in time. These are power controlled switches - transistors or thyristors operating in a pulsed mode and digital links in regulators.Time discretization significantly affects the stability of processes in the automatic control system. The theoretical analysis of such systems is rather complicated and requires a significant change in engineering approaches to analysis. In connection with the improvement of digital controllers and a significant increase in their performance, in recent years this problem has practically not been remembered. However, its mathematical "content" has not changed since the 80s of the 20th century, when discreteness began to play a major role among the problems hindering progress in automatic control systems, in terms of the transition to digital systems.In this paper, a new approach is proposed, which consists in interpreting the sampling operation by a link with the proposed frequency characteristic, which determines the suppression of input high-frequency signals. This link greatly simplifies engineering calculations and demonstrates the new capabilities of sampling systems. These possibilities include the rational distribution of digitalization resources - the number of bits and the sampling interval between the regulator channels, depending on the frequency range of the efficiency of these channels. Theoretical statements have been verified and confirmed by simulation. It is shown how this approach makes it possible to formulate new principles of construction of seemingly well-known controllers - PID controllers and variable structure systems (VSS).

Self-Tuning Fuzzy Sliding Controller for the Ship Heading Problem

2010 ◽  
Author(s):  
Nassim Khaled ◽  
Nabil G. Chalhoub
Keyword(s):  
Fuzzy Logic Controller ◽  
Sliding Mode ◽  
Variable Structure ◽  
Guidance System ◽  
Tuning Parameter ◽  
Variable Structure Systems ◽  
Modeling Uncertainties ◽  
Self Tuning ◽  
The Stability ◽  
Yaw Angle

A self-tuning fuzzy-sliding mode controller is presented in the current work. It aims at combining the advantages of the variable structure systems (VSS) theory with the self-tuning fuzzy logic controller. Neither the development of an accurate dynamic model of the plant nor the construction of a rule-based expert system is required for designing the controller. The only requirement is that the upper bound of the modeling uncertainties has to be known. The stability of the controlled system is ensured by forcing the tuning parameter to satisfy the sliding condition. The controller is implemented to control the heading of an under-actuated ship. The simulation results demonstrate the robust performance of the controller in accurately tracking the desired yaw angle specified by the guidance system in the presence of considerable modeling imprecision and environmental disturbances.

Design of Variable Structure Control with Bounded Inputs

2010 ◽  
Vol 29-32 ◽  
pp. 1175-1180
Author(s):  
Qing Kun Zhou ◽  
Sheng Jian Bai ◽  
Zhi Yong Zhang
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
Sliding Mode ◽  
Variable Structure ◽  
Closed Loop System ◽  
Variable Structure Systems ◽  
Structure Control ◽  
Variable Structure System ◽  
Lti System ◽  
The Stability

The design of variable structure system inputs which are constrained by saturation is studied. For a LTI system which satisfies some conditions, it is shown that appropriate bounded controllers guarantee the system’s global stability and maximize the sliding mode domain on the switching surfaces. Stability conditions of variable structure systems with constrained inputs are relaxed, and the stability of the closed-loop system is guaranteed by using passivity theory of linear passive systems. Moreover, nonlinear sliding surfaces are discussed for variable structure controller design, and a novel nonlinear switching surface is proposed. Finally, the proposed methods are applied to a 2nd order LTI system to show their usefulness.

Fuzzy Control-Based Synchronization of Fractional-Order Chaotic Systems With Input Nonlinearities

2018 ◽  
pp. 261-288 ◽  
Author(s):  
Abdesselem Boulkroune ◽  
Amina Boubellouta
Keyword(s):  
Fractional Order ◽  
Chaotic Systems ◽  
Controller Design ◽  
Variable Structure ◽  
Adaptive Controller ◽  
Projective Synchronization ◽  
Fuzzy Logic Systems ◽  
Bounded Disturbances ◽  
The Stability ◽  
Fuzzy Adaptive

This chapter addresses the fuzzy adaptive controller design for the generalized projective synchronization (GPS) of incommensurate fractional-order chaotic systems with actuator nonlinearities. The considered master-slave systems are with different fractional-orders, uncertain models, unknown bounded disturbances, and non-identical form. The suggested controller includes two keys terms, namely a fuzzy adaptive control and a fractional-order variable structure control. The fuzzy logic systems are exploited for approximating the system uncertainties. A Lyapunov approach is employed for determining the parameter adaptation laws and proving the stability of the closed-loop system. At last, simulation results are given to demonstrate the validity of the proposed synchronization approach.

Power-Electronics Converters: A Field Rich in Discontinuities

2001 ◽  
Author(s):  
Ali H. Nayfeh ◽  
Sudip K. Mazumder
Keyword(s):  
Closed Loop ◽  
Nonlinear Dynamical System ◽  
Variable Structure ◽  
Buck Converter ◽  
Switching Converters ◽  
Discontinuous Systems ◽  
Variable Structure Systems ◽  
Nonlinear Dynamical ◽  
Power Electronics Converters ◽  
The Stability

Abstract We demonstrate the need for treating switching converters as discontinuous systems in order to properly analyze their dynamics and stability. We also outline some concepts related to the stability analysis of these variable-structure systems. Using these concepts, we investigate the stability and dynamics of a stand alone and an integrated DC-DC buck converter, which represents a nonlinear dynamical system under closed-loop operation. We compare the results with some of the existing ones, which are based on small-signal analyses, and demonstrate the shortcomings of the latter.

scholarly journals A Method for Assessing the Stability of Digital Automatic Control Systems (ACS) with Discrete Elements. Hypothesis and Simulation Results

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6561
Author(s):  
Vladimir Kodkin ◽  
Alexander Baldenkov ◽  
Alexander Anikin
Keyword(s):  
Automatic Control ◽  
Control Systems ◽  
Variable Structure ◽  
Time Discretization ◽  
Discrete Elements ◽  
Digital Controllers ◽  
Variable Structure Systems ◽  
New Approach ◽  
Automatic Control Systems ◽  
The Stability

The article presents a new approach to the analysis of the stability of automatic systems with discrete links. In almost all modern automatic control systems (ACS), there are links that break signals in time. These are power controlled switches—transistors or thyristors operating in a pulsed mode and digital links in regulators. Time discretization significantly affects the stability of processes in the automatic control system. The theoretical analysis of such systems is rather complicated and requires a significant change in engineering approaches to analysis. With the improvement of digital controllers and a significant increase in their performance, this problem has practically been forgotten. However, its mathematical “content” has not changed since the 1980s when discreteness began to play a major role in hindering the transition to digital automatic control systems. In this paper, we propose a new approach that consists of interpreting the sampling operation by a link with the proposed frequency characteristic, which determines the suppression of input high-frequency signals. This link greatly simplifies engineering calculations and demonstrates the new capabilities of sampling systems. These possibilities include the rational distribution of digitalization resources—the number of bits and the sampling interval between the regulator channels, depending on the frequency range of the efficiency of these channels. We verify and confirm our theoretical statements through simulations and show how this approach makes it possible to formulate new principles of construction of seemingly well-known controllers—PID (Proportional Integral Differential) controllers and variable structure systems (VSS).

scholarly journals Suboptimal Disturbance Observer Design Using All Stabilizing Q Filter for Precise Tracking Control

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1434 ◽  
Author(s):  
Wonhee Kim ◽  
Sangmin Suh
Keyword(s):  
Design Method ◽  
Industrial Applications ◽  
Point Of View ◽  
Observer Design ◽  
Linear Matrix ◽  
External Disturbances ◽  
Closed Loop Systems ◽  
Control Target ◽  
The Stability ◽  
Unified Index

For several decades, disturbance observers (DOs) have been widely utilized to enhance tracking performance by reducing external disturbances in different industrial applications. However, although a DO is a verified control structure, a conventional DO does not guarantee stability. This paper proposes a stability-guaranteed design method, while maintaining the DO structure. The proposed design method uses a linear matrix inequality (LMI)-based H∞ control because the LMI-based control guarantees the stability of closed loop systems. However, applying the DO design to the LMI framework is not trivial because there are two control targets, whereas the standard LMI stabilizes a single control target. In this study, the problem is first resolved by building a single fictitious model because the two models are serial and can be considered as a single model from the Q-filter point of view. Using the proposed design framework, all-stabilizing Q filters are calculated. In addition, for the stability and robustness of the DO, two metrics are proposed to quantify the stability and robustness and combined into a single unified index to satisfy both metrics. Based on an application example, it is verified that the proposed method is effective, with a performance improvement of 10.8%.

Sign in / Sign up

Export Citation Format

Share Document