Control of Industrial Manipulators With Bounded Uncertainties

1987 ◽  
Vol 109 (1) ◽  
pp. 53-59 ◽  
Author(s):  
R. Shoureshi ◽  
M. J. Corless ◽  
M. D. Roesler
Keyword(s):  
Time Estimation ◽  
Control Technique ◽  
Robust Tracking Control ◽  
Load Variations ◽  
Exact Model ◽  
Control Scheme ◽  
Control Schemes ◽  
Industrial Manipulators ◽  
On Line ◽  
Real Time Estimation

Present on-line control schemes for robotic manipulators require high computing power to perform real-time estimation and adaptation and/or an exact model of the manipulator. These requirements result in impractical control schemes for real industrial manipulators. This paper presents a new robust tracking control technique for industrial manipulators in the presence of various uncertainties. It does not require an exact model of the manipulator and it compensates for uncertainties in the system dynamics, such as friction, and uncertain inputs including load variations. The controller consists of two portions: one for the nominal part of the system, and the other portion for uncertainties compensation. This control scheme is simulated for a General Electric P50 robot and the results are presented.

The Optimization of Time-Frequency Control: Using Non-Autonomous Time-Delay Feedback Systems as Example

2016 ◽  
Author(s):  
Chi-Wei Kuo ◽  
C. Steve Suh
Keyword(s):  
Time Delay ◽  
Dynamic Instability ◽  
Frequency Control ◽  
Frequency Resolution ◽  
Control Technique ◽  
Time Step ◽  
Time Frequency ◽  
Control Scheme ◽  
Fxlms Algorithm ◽  
On Line

A novel time-frequency nonlinear scheme demonstrated to be feasible for the control of dynamic instability including bifurcation, non-autonomous time-delay feedback oscillators, and route-to-chaos in many nonlinear systems is applied to the control of a time-delayed system. The control scheme features wavelet adaptive filters for simultaneous time-frequency resolution. Specifically Discrete Wavelet transform (DWT) is used to address the nonstationary nature of a chaotic system. The concept of active noise control is also adopted. The scheme applied the filter-x least mean square (FXLMS) algorithm which promotes convergence speed and increases performance. In the time-frequency control scheme, the FXLMS algorithm is modified by adding an adaptive filter to identify the system in real-time in order to construct a wavelet-based time-frequency controller capable of parallel on-line modeling. The scheme of such a construct, which possesses joint time-frequency resolution and embodies on-line FXLMS, is able to control non-autonomous, nonstationary system responses. Although the controller design is shown to successfully moderate the dynamic instability of the time-delay feedback oscillator and unconditionally warrant a limit cycle, parameters are required to be optimized. In this paper, the setting of the control parameters such as control time step, sampling rate, wavelet filter vector, and step size are studied and optimized to control a time-delay feedback oscillators of a nonautonomous type. The time-delayed oscillators have been applied in a broad set of fields including sensor design, manufacturing, and machine dynamics, but they can be easily perturbed to exhibit complex dynamical responses even with a small perturbation from the time-delay feedback. These responses for the system have a very negative impact on the stability, and thus output quality. Through employingfrequency-time control technique, the time responses of the time-delay feedback system to external disturbances are properly mitigated and the frequency responses are also suppressed, thus rendering the controlled responses quasi-periodic.

scholarly journals Fuzzy Fractional-Order PID Controller for Fractional Model of Pneumatic Pressure System

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
M. Al-Dhaifallah ◽  
N. Kanagaraj ◽  
K. S. Nisar
Keyword(s):  
Fractional Order ◽  
Operating Conditions ◽  
Effective Control ◽  
External Disturbances ◽  
Pressure System ◽  
Pneumatic Pressure ◽  
Load Variations ◽  
Control Scheme ◽  
Control Schemes ◽  
Fractional Order Pid

This article presents a fuzzy fractional-order PID (FFOPID) controller scheme for a pneumatic pressure regulating system. The industrial pneumatic pressure systems are having strong dynamic and nonlinearity characteristics; further, these systems come across frequent load variations and external disturbances. Hence, for the smooth and trouble-free operation of the industrial pressure system, an effective control mechanism could be adopted. The objective of this work is to design an intelligent fuzzy-based fractional-order PID control scheme to ensure a robust performance with respect to load variation and external disturbances. A novel model of a pilot pressure regulating system is developed to validate the effectiveness of the proposed control scheme. Simulation studies are carried out in a delayed nonlinear pressure regulating system under different operating conditions using fractional-order PID (FOPID) controller with fuzzy online gain tuning mechanism. The results demonstrate the usefulness of the proposed strategy and confirm the performance improvement for the pneumatic pressure system. To highlight the advantages of the proposed scheme a comparative study with conventional PID and FOPID control schemes is made.

Commissioning and Operation of a Direct Digital Control Computer on a Cement Plant

1970 ◽  
Vol 3 (5) ◽  
pp. T77-T88 ◽  
Author(s):  
A. D. Barton ◽  
D. G. Jenkins ◽  
F. P. Lees ◽  
R. W. Murtagh
Keyword(s):  
Digital Control ◽  
Raw Materials ◽  
Automatic Calibration ◽  
Cement Plant ◽  
Process Characteristics ◽  
Control Scheme ◽  
Control Schemes ◽  
Control Computer ◽  
On Line ◽  
Direct Digital Control

The installation and commissioning of an on-line computer on a new cement plant is described. The computer carries out direct digital control, although conventional controllers are also provided. Part I of the paper gives an account of the background to the project, the process characteristics and the computer functions and an assessment of the value of the computer. The main functions performed are control of raw materials blending and of the kiln. A mathematical model has been used for the development of the kiln control scheme. The computer has assisted in learning about the process, in overcoming commissioning difficulties and in developing control schemes both with and without the use of models. Direct digital control has made possible finer adjustments to valves and set points, has allowed automatic calibration of an important feed flow meter and has made the implementation of alternative control loop configurations easier. Part II gives a detailed description of the computer system and an assessment of its reliability. The availability achieved over a three-year period is 99.1 per cent. Many of the faults which have occurred have been identified and could in future be eliminated in design. It is expected that the availability attainable after such improvements would be about 99.9 per cent.

Real-Time Estimation of Cutting Process Parameters in Turning

1984 ◽  
Vol 106 (3) ◽  
pp. 218-221 ◽  
Author(s):  
O. Masory
Keyword(s):  
Adaptive Control ◽  
Real Time ◽  
Process Parameters ◽  
Time Estimation ◽  
Cutting Process ◽  
Process Variables ◽  
Simple Method ◽  
Control Optimization ◽  
On Line ◽  
Real Time Estimation

A simple method for real-time estimation of the parameters which characterize the relation between cutting force and feed in turning is described. The method produces very accurate results which make it suitable for use in Adaptive Control Constrain (ACC) and Adaptive Control Optimization (ACO) systems. In both cases, models describing different cutting process variables are assumed in which constants are predetermined by off-line experiments. The described method will make it possible to determine these constants on-line.

Robust Passivity-based Control scheme for 1.26 KW PEM Fuel Cell under temperature and load variations

2021 ◽  
pp. 1-10
Author(s):  
Abdelaziz Zaidi ◽  
Asma Charaabi ◽  
Oscar Barambones ◽  
Nadia Zanzouri
Keyword(s):  
Closed Loop ◽  
Sliding Mode ◽  
Load Resistance ◽  
Current Sensor ◽  
Closed Loop System ◽  
Load Variations ◽  
Load Variation ◽  
Incremental Value ◽  
Control Scheme ◽  
Control Schemes

Abstract The Model Based System Engineering (MBSE) is based on simplified mathematical models that reflects the dynamic behavior of the systems. These latter are most of time nonlinear and need control schemes taking in consideration exogenous perturbations. The main contribution of this paper is the design of a robust passivity based sliding mode control scheme for a 1.26 KW PEMFC. The uncertainties considered in this paper are temperature and load variation. The FC reference current is adapted in a linear transformation by introducing a temperature sensor. This information is present in most of commercial PEMFC and not used in the closed-loop system. Moreover, the proposed approach cancels the errors caused by the average approach modeling and the observer (the part which replaces current sensor). Robustness against load variation is assured via a proportional integral compensation of the incremental value of load resistance. The performance of the controller and the effectiveness of our approach is shown through the simulation with MATLAB-SIMULINK software.

Distributed Robust Tracking Control of Multiple Mobile Robots Formation

2011 ◽  
Vol 65 ◽  
pp. 208-213
Author(s):  
Tian Tian Yang ◽  
Zhi Bao Su ◽  
Jin Liu ◽  
Hong Meng
Keyword(s):  
Optimal Control ◽  
Mobile Robots ◽  
Tracking Control ◽  
Decision Variable ◽  
Robust Tracking Control ◽  
Initial State ◽  
Formation Tracking ◽  
Control Scheme ◽  
Distributed Optimal Control Problems ◽  
On Line

This paper presents a distributed robust formation tracking control scheme for a team of mobile robots with parametric uncertainties and input constraints. First for each interacting robot whose dynamics are uncoupled, distributed optimal control problems are introduced. Then a distributed robust moving horizon control scheme is consequently formulated as on-line solving each constrained optimal problem synchronously at each sampling time. The optimal control problem includes the initial state of the model employed in the problem as a decision variable. It is also shown that the proposed control scheme guarantees closed-loop stability. Simulation is performed to illustrate the proposed control law.

A machine for real-time estimation of the tribological characteristics of materials

2020 ◽  
Vol 86 (4) ◽  
pp. 61-65
Author(s):  
M. V. Abramchuk ◽  
R. V. Pechenko ◽  
K. A. Nuzhdin ◽  
V. M. Musalimov
Keyword(s):  
Real Time ◽  
Time Estimation ◽  
Tribological Characteristics ◽  
Continuous Processing ◽  
Friction Machine ◽  
Dynamic Friction Coefficient ◽  
Displacement Sensors ◽  
Frictional Interaction ◽  
Real Time Estimation ◽  
Automated Quality Control

A reciprocating friction machine Tribal-T intended for automated quality control of the rubbing surfaces of tribopairs is described. The distinctive feature of the machine consists in implementation of the forced relative motion due to the frictional interaction of the rubbing surfaces fixed on the drive and conjugate platforms. Continuous processing of the signals from displacement sensors is carried out under conditions of continuous recording of mutual displacements of loaded tribopairs using classical approaches of the theory of automatic control to identify the tribological characteristics. The machine provides consistent visual real time monitoring of the parameters. The MATLAB based computer technologies are actively used in data processing. The calculated tribological characteristics of materials, i.e., the dynamic friction coefficient, damping coefficient and measure of the surface roughness, are presented. The tests revealed that a Tribal-T reciprocating friction machine is effective for real-time study of the aforementioned tribological characteristics of materials and can be used for monitoring of the condition of tribo-nodes of machines and mechanisms.

Onboard Real-time Estimation of Mean Orbital Elements with Atmospheric Drag

2013 ◽  
Vol 39 (10) ◽  
pp. 1722
Author(s):  
Zhao-Wei SUN ◽  
Wei-Chao ZHONG ◽  
Shi-Jie ZHANG ◽  
Jian ZHANG
Keyword(s):  
Real Time ◽  
Time Estimation ◽  
Atmospheric Drag ◽  
Orbital Elements ◽  
Real Time Estimation

scholarly journals Nonlinear Current-Mode Control of SCIG Wind Turbines

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 55
Author(s):  
Nicholas Hawkins ◽  
Bhagyashri Bhagwat ◽  
Michael L. McIntyre
Keyword(s):  
Current Mode ◽  
Nonlinear Controller ◽  
Flux Observer ◽  
Current Mode Control ◽  
Mode Control ◽  
Squirrel Cage ◽  
Control Scheme ◽  
Control Schemes ◽  
Rotor Flux ◽  
Squirrel Cage Induction Generator

In this paper, a nonlinear controller is proposed to manage the rotational speed of a full-variable Squirrel Cage Induction Generator wind turbine. This control scheme improves upon tractional vector controllers by removing the need for a rotor flux observer. Additionally, the proposed controller manages the performance through turbulent wind conditions by accounting for unmeasurable wind torque dynamics. This model-based approach utilizes a current-based control in place of traditional voltage-mode control and is validated using a Lyapunov-based stability analysis. The proposed scheme is compared to a linear vector controller through simulation results. These results demonstrate that the proposed controller is far more robust to wind turbulence than traditional control schemes.

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