scholarly journals L 1 Adaptive Fractional Control Optimized by Genetic Algorithms with Application to Polyarticulated Robotic Systems

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Boutheina Maalej ◽  
Rim Jallouli Khlif ◽  
Chokri Mhiri ◽  
Mohamed Habib Elleuch ◽  
Nabil Derbel
Keyword(s):  
Genetic Algorithms ◽  
Adaptive Control ◽  
Time Lag ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Control Approach ◽  
Low Pass ◽  
The Stability ◽  
Fractional Control ◽  
Model Reference Adaptive

Recently, an adaptive control approach has been proposed. This approach, named L 1 adaptive control, involves the insertion of a low-pass filter at the input of the Model Reference Adaptive Control (MRAC). This controller has been designed to overcome several limitations of classical adaptive controllers such as (i) the initialization of estimated parameters, (ii) the stability problems with high adaptation gains, and (iii) the appropriate parameter excitation. In this paper, a new design of the filter is presented, used for L 1 adaptive control, for which the desired performances are guaranteed (appropriate values of the control during start-up, a high filtering of noises, a reduced time lag, and a reduced energy consumption). Parameters of the new proposed filter have been optimised by genetic algorithms. The proposed L 1 adaptive fractional control is applied to a polyarticulated robotic system. Simulation results show the efficiency of the proposed control approach with respect to the classical L 1 adaptive control in the nominal case and in the presence of a multiplicative noise.

Application of Slipped-Window Integrator and Repetitive Predictor in APF

2014 ◽  
Vol 556-562 ◽  
pp. 3585-3589
Author(s):  
Meng Qiong Wang ◽  
Chun Yu Xu
Keyword(s):  
Tracking Control ◽  
Pulse Width Modulation ◽  
Time Lag ◽  
Active Power Filter ◽  
Active Power ◽  
Modulation Method ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Power Filter ◽  
Low Pass

In view of the shortages time lag existing in traditional digital low-pass filter in Active Power Filter (Active Power Filter, APF), this paper proposes to adopt slipped-window integrator to realize low-pass filter in harmonic current detection.The current tracking control uses Space Vector Pulse Width Modulation method. Meanwhile, the repetitive predictor is applied so as to improve the real-time performance of the compensation current tracking control. Built a three-phase shunt active power filter simulation model in Matlab/Simulink environment and take experiment under the low pressure condition. The results show that slipped-window integrator and deadbeat current mothod can acquire good dynamic response performance as well as high precision.

Disturbance Elimination of Buck-Converter with Resonant LPF via ILQ Servo-System

2014 ◽  
Vol 492 ◽  
pp. 493-498
Author(s):  
Shuhei Shiina ◽  
Sidshchadhaa Aumted ◽  
Hiroshi Takami
Keyword(s):  
Transfer Functions ◽  
Design Method ◽  
Servo System ◽  
State Equation ◽  
Buck Converter ◽  
Linear Quadratic ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
The Stability

The proposed optimal control on the basis of both current and voltage of the buck-converter is designed to be based on Inverse Linear Quadratic (ILQ) design method with the resonant low pass filter, which eliminates the disturbance by appended disturbance compensator. The designed scheme is composed of the state equation, an optimal ILQ solution, the ILQ servo-system with the disturbance elimination, the optimal basic gain, the optimal condition, the transfer functions and the disturbance compensator. Our results show the proposed strategy is the stability and robust control and has been made to improve ILQ control for the disturbance elimination of the output response, which guarantees the optimal gains on the basis of polynomial pole assignment.

ADAPTIVE CONTROL OF CHAOTIC n-SCROLL CHUA'S CIRCUIT

2006 ◽  
Vol 16 (04) ◽  
pp. 1089-1096 ◽  
Author(s):  
YAN-LI ZOU ◽  
JIE ZHU ◽  
GUANRONG CHEN
Keyword(s):  
Adaptive Control ◽  
Control Method ◽  
Control Methods ◽  
Chua’S Circuit ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Chua's Circuit ◽  
Low Pass ◽  
Attraction Basins ◽  
And Performance

In this paper, stabilization of fixed points of n-scroll Chua's circuit is investigated. Two adaptive control methods are proposed. One is based on an unstable low pass filter; the other is based on a stable and an unstable low pass filter. The simulation results verify the effectiveness of the two proposed control methods and performance comparisons show that the second control method is superior to the first one with regard to control speed and attraction basins.

scholarly journals Adaptive Differential Thrust Methodology for Lateral/Directional Stability of an Aircraft with a Completely Damaged Vertical Stabilizer

2018 ◽  
Vol 2018 ◽  
pp. 1-18
Author(s):  
Long K. Lu ◽  
Kamran Turkoglu
Keyword(s):  
Adaptive Control ◽  
Commercial Aircraft ◽  
Control Approach ◽  
Directional Stability ◽  
Fatal Crash ◽  
And Performance ◽  
The Stability ◽  
And Control ◽  
Model Reference Adaptive ◽  
Differential Thrust

This paper investigates the utilization of differential thrust to help a commercial aircraft with a damaged vertical stabilizer in order to regain its lateral/directional stability. In the event of an aircraft losing its vertical stabilizer, the consequential loss of the lateral/directional stability and control is likely to cause a fatal crash. In this paper, an aircraft with a completely damaged vertical stabilizer is investigated, and a unique differential thrust-based adaptive control approach is proposed to achieve a stable flight envelope. The propulsion dynamics of the aircraft is modeled as a system of differential equations with engine time constant and time delay terms to study the engine response time with respect to a differential thrust input. The proposed differential thrust control module is then presented to map the rudder input to differential thrust input. Model reference adaptive control based on the Lyapunov stability approach is implemented to test the ability of the damaged aircraft to track the model aircraft’s (reference) response in an extreme scenario. Investigation results demonstrate successful application of such differential thrust approach to regain lateral/directional stability of a damaged aircraft with no vertical stabilizer. Finally, the conducted robustness and uncertainty analysis results conclude that the stability and performance of the damaged aircraft remain within desirable limits and demonstrate a safe flight mission through the proposed adaptive control methodology.

Motion Trajectory Tracking Method for Vehicle Steering Based on Dynamic Surface Control

2012 ◽  
Vol 220-223 ◽  
pp. 1023-1027
Author(s):  
Jun Gu ◽  
Jun Fan ◽  
Huan Shen
Keyword(s):  
Trajectory Tracking ◽  
Tracking System ◽  
Lateral Position ◽  
Dynamic Surface Control ◽  
Dynamic Surface ◽  
Pass Filter ◽  
High Order Derivative ◽  
Low Pass Filter ◽  
Low Pass ◽  
The Stability

Focus on the problem of steering trajectory tracking, a tracking control law based on dynamic surface is proposed. Other than existing methods, this paper considers combined lateral position and yaw synchronously control. The first order low pass filter is used to obtain the differential items of the lateral position and yaw, so as to eliminate the high order derivative from the final expression of the close loop law. This characteristic is very useful especially in real applications. The Lyapunov approach is employed to analysis the stability of the tracking system, and the convergence of the system is achieve. Simulation result validates the outstanding effectiveness of the proposed method for steering trajectory tracking.

Performance enhancement of model reference adaptive control through normalized Lyapunov design

2019 ◽  
Vol 233 (9) ◽  
pp. 1209-1220
Author(s):  
Mohammad-G Farajzadeh-D ◽  
S. K. Hosseini Sani ◽  
Alireza Akbarzadeh
Keyword(s):  
Adaptive Control ◽  
Tracking Error ◽  
Model Reference Adaptive Control ◽  
Fast Convergence ◽  
The Other ◽  
Model Reference ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Lyapunov Design ◽  
Model Reference Adaptive

Model reference adaptive control is one of the popular methods that simultaneously deals with uncertainties and reduces conservatism. However, it usually suffers from slow convergence and poor tracking at the beginning of the adaptation. On the other hand, attaining fast convergence by increasing the learning rate could cause oscillation in the control response, which results in system instability. Some of the solutions that have been presented so far use prediction error, low-pass filter, or normalizing the control signal. In this article, a novel robust normalized Lyapunov design is proposed for model reference adaptive control to achieve fast convergence and to avoid oscillatory response. In contrast to the other solutions, it uses a new Lyapunov function to guarantee the global asymptotic stability and to prove the robustness of the closed-loop system against bounded uncertainties. The performance of the proposed method is compared with two other model reference adaptive controls using simulations. In addition, an industrial selective compliance assembly robot arm is used for further verification. Results indicate that that the proposed normalized Lyapunov design reduces the tracking error by 62.4% on average; it also has faster convergence and shows robustness against uncertainties such as payload changes.

Design of Modified Repetitive Controller for T–S Fuzzy Systems

2019 ◽  
Vol 23 (3) ◽  
pp. 602-610 ◽  
Author(s):  
Manli Zhang ◽  
Min Wu ◽  
Luefeng Chen ◽  
Pan Yu ◽  
◽  
...  
Keyword(s):  
Stability Condition ◽  
Repetitive Control ◽  
Tracking Performance ◽  
Linear Matrix ◽  
Continuous Control ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Control Approach ◽  
The Stability ◽  
Repetitive Controller

A repetitive controller contains a pure-delay positive-feedback loop that makes it difficult to stabilize a strictly proper system. A low-pass filter is inserted in a repetitive controller to relax the stability condition of the modified repetitive-control system at the cost of degrading the tracking performance. In this study, a modified repetitive-control approach is developed, which reaches a balance between the stability and tracking performance for a class of affine nonlinear systems based on the Takagi–Sugeno fuzzy model. First, a 2D model is established to adjust continuous control and discrete learning actions preferentially induced by exploiting the 2D property in a repetitive-control process. Then, the Lyapunov stability theory and 2D system theory are used to derive a sufficient stability condition in the form of linear matrix inequalities to design parallel-distributed-compensation-based state-feedback controllers. Finally, an application-oriented example is used, and a comparison is performed to show that an extra variable is introduced such that the developed method has a better tracking performance.

Methods and Algorithms for Correcting Kinematic Equations in the Problem of Determining the Orientation of an Object

2021 ◽  
Vol 22 (9) ◽  
pp. 494-504
Author(s):  
V. V. Aleshkin ◽  
R. A. Zrazhevsky ◽  
P. N. Golovanov ◽  
V. O. Marusich
Keyword(s):  
Asymptotic Stability ◽  
Frequency Characteristics ◽  
Noise Power ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Orientation System ◽  
Low Pass ◽  
Angular Velocities ◽  
Compensation Of Errors ◽  
The Stability

Algorithms of a strapdown inertial orientation system with an inertial measurement module consisting of a three-component gyroscope, accelerometer, and magnetometer are considered. The aim of the work is to improve the algorithms for processing sensor information to ensure the asymptotic stability of the system, tuning for the Schuler period and the low-pass filter with a given bandwidth. The kinematic Poisson equations with positional and integral-positional correction based on the information of accelerometers and magnetometers are considered. The stability and frequency characteristics of the system in relation to the sensor output signals are analyzed. It is shown that the positional correction in each channel does not allow you to adjust the system for the Schuler period. The integral-positional correction allows this adjustment, but in relation to the gyroscope signals, the system is a bandpass filter and does not suppress noise in the bandwidth. The advantages of using positional correction with cross-links in the sense of tuning the frequency characteristics of the system to the Sharper frequency and the third-order low-pass filter are shown. The analysis of the influence of angular velocities confirmed the asymptotic stability of the system with their changes in a given range. The results of mathematical modeling confirmed the compensation of errors in the initial orientation system display, the reduction of noise power in the estimates of the orientation angles in relation to the noise in the sensor signals, and the ability to configure the system for the Schuler period.

A ZERO PHASE-LAG HOMODYNE DEMODULATION TECHNIQUE FOR SYNCHRONOUS MEASUREMENT APPLICATIONS AND ITS FPGA IMPLEMENTATION

2005 ◽  
Vol 14 (04) ◽  
pp. 771-791 ◽  
Author(s):  
B. DAM ◽  
K. BANERJEE ◽  
K. MAJUMDAR ◽  
R. BANERJEE ◽  
D. PATRANABIS
Keyword(s):  
A Priori ◽  
Phase Error ◽  
Time Lag ◽  
Fpga Implementation ◽  
Phase Lag ◽  
Processor Time ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Square Wave ◽  
Low Pass

A simple homodyne direct digital demodulation technique that is insensitive to sensor induced phase-error and its innovative FPGA implementation are presented here. This novel demodulation scheme does not need a low pass filter; thereby the inherent filter time lag is eliminated. A direct digital read-out of the demodulated signal, i.e., the measurand value, is obtained through analog-to-digital conversion of the modulated signal at an instant that coincides with its peak. This peak sampling eliminates the processor time required in quadrature demodulators to obtain the measurand from the in-phase and quadrature components. For this purpose a quadrature square wave is first generated from the reference carrier. Digital measures of carrier time period and sensor induced time lag/lead are used to ensure that the rising edges of this quadrature square wave coincide with the peak instants of the modulated signal. The required sampling instants for digitization of the modulated signal are generated in synchronism with its rising edges. The digital read-out of the measurand is directly obtained without taking recourse to the standard sequence of multiplication, low-pass filtering and the subsequent processing common in existing synchronous phase-sensitive demodulators. With an a priori knowledge of the sensor-type used, this innovative FPGA-based implementation accommodates sensors introducing lagging or leading phase-shift in the modulated carrier.

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