Comparison of robust optimal QFT controller with TFC and MFC controller in a multi-input multi-output system

2020 ◽  
Vol 1 (1) ◽  
pp. 151-161
Author(s):  
Mohammad Reza Gharib ◽  
Keyword(s):  
Transfer Function ◽  
Degrees Of Freedom ◽  
System Stability ◽  
Optimization Process ◽  
Tracking Problem ◽  
Robust Controller ◽  
Robot Controller ◽  
Process System ◽  
Output System ◽  
Nonlinear Plant

This paper suggests a practical approach for the development of a stable robot controller using the Quantitative Feedback Principle (QFT). Robot manipulators have a multivariable nonlinear transfer function, the implementation of the QFT method includes, first the conversion of their nonlinear plant into a group of linear and uncertain plant set, and then an ideal robust controller for each set has been designed. To demonstrate the effectiveness of our algorithm, we show the implementation of the two degrees of freedom manipulator. In the approach provided, the controller has been designed directly by specifying and optimizing the transfer function coefficients using a genetic algorithm. The consistency and limitations of the method are considered to be the restrictions of the problem in the optimization process. System stability and tracking problem are perceived to be the limitations of the system in the optimization process. Non-linear simulations on the tracking problem are carried out and the results illustrate the performance of the controllers. Finally, the controller constructed based on the QFT approach is compared with the TFC and MFC (Fuzzy) controllers and it is shown that the QFT methodology indicates a controller that has increased control efficiency.

scholarly journals Doubly fed induction generators to enhance inter-area damping based on a Robust controller: $${{\varvec{H}}}_{2}/{{\varvec{H}}}_{\infty }$$ Control

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Ali Goodarzi ◽  
Ali Mohammad Ranjbar ◽  
Moslem Dehghani ◽  
Mina GhasemiGarpachi ◽  
Mohammad Ghiasi
Keyword(s):  
Working Conditions ◽  
Reactive Power ◽  
Wind Farms ◽  
System Stability ◽  
Pole Placement ◽  
Linear Matrix ◽  
Robust Controller ◽  
Induction Generators ◽  
Doubly Fed ◽  
Oscillation Damping

AbstractIn this study, an auxiliary damping controller based on a robust controller considering the active and reactive power control loops for a doubly-fed induction generator for wind farms is proposed. The presented controller is able to improve the inter-area oscillation damping. In addition, the proposed controller applies only one accessible local signal as the input; however, it can improve the inter-area oscillation damping and, consequently the system stability for the various working conditions and uncertainties. The oscillatory modes of the system are appointed using the linear analysis. Then, the controller’s parameters are determined using the robust control approaches ($${H}_{\infty }/{H}_{2})$$ H ∞ / H 2 ) with the pole placement and linear matrix inequality method. The results of the modal analysis and time-domain simulations confirm that the controller develops the inter-area oscillation damping under the various working conditions and uncertainties.

Stability of Ring-Type MEMS Gyroscopes Subjected to Stochastic Angular Speed Fluctuation

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Samuel F. Asokanthan ◽  
Soroush Arghavan ◽  
Mohamed Bognash
Keyword(s):  
Angular Velocity ◽  
Degrees Of Freedom ◽  
Microelectromechanical Systems ◽  
Damping Ratio ◽  
Operating Conditions ◽  
System Stability ◽  
System Response ◽  
Ring Type ◽  
Mems Gyroscopes ◽  
The Stability

Effect of stochastic fluctuations in angular velocity on the stability of two degrees-of-freedom ring-type microelectromechanical systems (MEMS) gyroscopes is investigated. The governing stochastic differential equations (SDEs) are discretized using the higher-order Milstein scheme in order to numerically predict the system response assuming the fluctuations to be white noise. Simulations via Euler scheme as well as a measure of largest Lyapunov exponents (LLEs) are employed for validation purposes due to lack of similar analytical or experimental data. The response of the gyroscope under different noise fluctuation magnitudes has been computed to ascertain the stability behavior of the system. External noise that affect the gyroscope dynamic behavior typically results from environment factors and the nature of the system operation can be exerted on the system at any frequency range depending on the source. Hence, a parametric study is performed to assess the noise intensity stability threshold for a number of damping ratio values. The stability investigation predicts the form of threshold fluctuation intensity dependence on damping ratio. Under typical gyroscope operating conditions, nominal input angular velocity magnitude and mass mismatch appear to have minimal influence on system stability.

Offline Programming for an Arc Welding Robot with Redundant DOF

2012 ◽  
Vol 184-185 ◽  
pp. 1623-1627 ◽  
Author(s):  
Huan Ming Chen ◽  
Zhou Ping Liu
Keyword(s):  
Arc Welding ◽  
Degrees Of Freedom ◽  
Motion Path ◽  
Welding Parameters ◽  
Programming System ◽  
Robot Controller ◽  
Offline Programming ◽  
Kinematics Simulation ◽  
Communication Module ◽  
Saddle Shape

To raise the programming efficiency of arc welding robots, the offline programming system was developed for a Motoman-UP20 robot with redundant degrees of freedom in VC++ integration environment. The system consists of kinematics analysis, motion simulation, welding trajectory plan, welding parameters plan and job file generating module. It can plan the motion path and posture of welding gun for saddle-shape seams, and display the workpiece on the interface synchronically. Job instructions can be made step by step, or generated automatically. Kinematics simulation module and communication module are integrated together, and job files can be exchanged between PC and robot controller via Ethernet to realize remote control.

Structural Modification Simulation: Sensitivity Analysis and the Reanalysis of Modified Structure

1991 ◽  
Author(s):  
Debao Li ◽  
Fangze Li ◽  
Peiming Xu
Keyword(s):  
Sensitivity Analysis ◽  
Transfer Function ◽  
Coordinate Transformation ◽  
Degrees Of Freedom ◽  
Structural Modification ◽  
Function Analysis ◽  
Dump Truck ◽  
Analysis Method ◽  
Transfer Function Analysis ◽  
Dynamic Modification

Abstract This paper deals with the dynamic modification simulation of the structure. The expressions of sensitivity analysis of the system with non-proportional damping and proportional damping are derived at first. As for the reanalysis of modified structure, here we deal with the system to which the modification do not cause any change of the degrees of freedom. Transfer function analysis method and the method of twice coordinate transformation are expounded. As a successful example, the modification simulation of the frame of a dump truck is explained.

A simulation study of nonideal mixing effect on the dynamic response of an exothermic CSTR with Cholette’s model

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chane-Yuan Yang ◽  
Yu-Shu Chien ◽  
Jun-Hong Chou
Keyword(s):  
Transfer Function ◽  
Dynamic Response ◽  
The Other ◽  
System Stability ◽  
Mixing Effect ◽  
Characteristic Roots ◽  
Mixing Parameter ◽  
Perfect Mixing ◽  
And Control ◽  
Inverse Response

Abstract The study of nonideal mixing effect on the dynamic behaviors of CSTRs has very rarely been published in the literature. In this work, Cholette’s model is employed to explore the nonideal mixing effect on the dynamic response of a nonisothermal CSTR. The analysis shows that the mixing parameter n (the fraction of the feed entering the zone of perfect mixing) and m (the fraction of the total volume of the reactor), indeed affect the characteristic roots of transfer function of a real CSTR, which determine the system stability. On the other hand, the inverse response and overshoot response are also affected by the nonideal mixing in a nonisothemal CSTR. These results are of much help for the design and control of a real CSTR.

scholarly journals Designing a GA-Based Robust Controller For Load Frequency Control (LFC)

2018 ◽  
Vol 8 (2) ◽  
pp. 2633-2639 ◽  
Author(s):  
K. Soleimani ◽  
J. Mazloum
Keyword(s):  
Power Systems ◽  
Power System ◽  
Power Plants ◽  
Frequency Control ◽  
Load Frequency Control ◽  
System Stability ◽  
Robust Controller ◽  
Power Flux ◽  
Pi Controllers ◽  
Multiple Units

Power systems include multiple units linked together to produce constantly moving electric power flux. Stability is very important in power systems, so controller systems should be implemented in power plants to ensure power system stability either in normal conditions or after the events of unwanted inputs and disorder. Frequency and active power control are more important regarding stability. Our effort focused on designing and implementing robust PID and PI controllers based on genetic algorithm by changing the reference of generating units for faster damping of frequency oscillations. Implementation results are examined on two-area power system in the ideally state and in the case of parameter deviation. According to the results, the proposed controllers are resistant to deviation of power system parameters and governor uncertainties.

A Human Arm’s Mechanical Impedance Tuning Method for Improving the Stability of Haptic Rendering

Robotica ◽  
2020 ◽  
pp. 1-13
Author(s):  
Xiong Lu ◽  
Beibei Qi ◽  
Hao Zhao ◽  
Junbin Sun
Keyword(s):  
Degrees Of Freedom ◽  
External Disturbance ◽  
Mechanical Impedance ◽  
System Stability ◽  
Tuning Method ◽  
Rigid Objects ◽  
Human Arm ◽  
Human Operators ◽  
And Performance ◽  
The Stability

SUMMARY Rendering of rigid objects with high stiffness while guaranteeing system stability remains a major and challenging issue in haptics. Being a part of the haptic system, the behavior of human operators, represented as the mechanical impedance of arm, has an inevitable influence on system performance. This paper first verified that the human arm impedance can unconsciously be modified through imposing background forces and resist unstable motions arising from external disturbance forces. Then, a reliable impedance tuning (IT) method for improving the stability and performance of haptic systems is proposed, which tunes human arm impedance by superimposing a position-based background force over the traditional haptic workspace. Moreover, an adaptive IT algorithm, adjusting the maximum background force based on the velocity of the human arm, is proposed to achieve a reasonable trade-off between system stability and transparency. Based on a three-degrees-of-freedom haptic device, maximum achievable stiffness and transparency grading experiments are carried out with 12 subjects, which verify the efficacy and advantage of the proposed method.

Rotor Dynamics of Flywheel Energy Storage Systems

1991 ◽  
Vol 113 (1) ◽  
pp. 11-18 ◽  
Author(s):  
C. P. Jayaraman ◽  
J. A. Kirk ◽  
D. K. Anand ◽  
M. Anjanappa
Keyword(s):  
Control Systems ◽  
Degrees Of Freedom ◽  
Magnetic Bearing ◽  
System Stability ◽  
Dynamic Equations ◽  
Dynamic Coupling ◽  
First Order ◽  
Torque Response ◽  
Resonance Frequencies ◽  
Computer Simulation Program

This paper deals with the dynamic analysis of the magnetic bearing stack system. The stack consists of a single flywheel supported by two magnetic bearings. To model the system, the dynamic equations of a magnetically suspended flywheel are derived. Next, the four control systems controlling the four degrees-of-freedom of the stack are incorporated into the model. The resulting dynamic equations are represented as first-order differential equations in a matrix form. A computer simulation program was then used to simulate the working of the magnetic bearing stack. Real time plots from the simulation are used to show the effect of dynamic coupling on torque response. Frequency response is used to determine the resonance frequencies of the stack system. It is found that system stability depends on flywheel speed. On the basis of the above results suggestions are made to improve stability and allow the stack to be spun beyond 60,000 rpm.

Sequential Time-Optimal Algorithm for Extended Path Tracking Problem

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Gábor Csorvási ◽  
István Vajk
Keyword(s):  
Degrees Of Freedom ◽  
Optimal Algorithm ◽  
Real Life ◽  
Path Tracking ◽  
Robotic Arm ◽  
Tracking Problem ◽  
Six Degrees Of Freedom ◽  
Time Optimal ◽  
Path Tracking Algorithm ◽  
Extended Path

Abstract This paper presents a fast and easily implementable path tracking algorithm for robots. Usually, for a path tracking problem, the goal is to move the robot on a predefined path, while the joint velocities and accelerations are kept within their limits. This paper deals with the extended case, constraining the forces applied to the objects at the manipulator. First, a problem with a special set of constraints is presented, and a sequential solver method is formulated. The presented sequential solver algorithm has significant computational benefits compared to the direct transcription approach. Then, a practical example is introduced where the proposed algorithm can be applied. At last, the algorithm is validated by real-life experimental results with a six degrees-of-freedom robotic arm.

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