A generalized control scheme for system uncertainty estimation and cancellation

2021 ◽  
pp. 014233122110105
Author(s):  
Qing-Guo Wang ◽  
Tao Liu ◽  
Zhuo-Yun Nie ◽  
Shoulin Hao ◽  
Xuhui Ren ◽  
...  
Keyword(s):  
External Disturbance ◽  
Parameter Tuning ◽  
System Uncertainty ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Control Scheme ◽  
Low Pass ◽  
Complete Set ◽  
Error Formulas ◽  
Necessary And Sufficient

This paper addresses the control of a continuous-time system with possibly large uncertainty of unknown internal dynamics or external disturbance. A novel control scheme is proposed to estimate and cancel the system uncertainty effectively so as to enhance disturbance rejection (DR) performance. Unlike asymptotic analysis with infinite gain in the literature, the estimation transient analysis is carried out for the proposed scheme with a finite estimator gain and the precise error formulas are derived, based on a classical low-order plant description. The control performance associated with a realizable gain is quantified by tight bounds with respect to the ideal case, which enables easy parameter tuning. The necessary and sufficient condition for the internal stability of the control system is established, along with a D-decomposition method for determining the complete set of the gain intervals that could internally stabilize the plant. In the presence of measurement noise, a low-pass filter is introduced to attenuate its adverse effect. Simulations and semi-realistic experiments are performed to demonstrate the effectiveness of the proposed scheme, which shows evident improvement on DR performance over the well-known active DR control.

Characterization of Low-pass Filters on Local Fields of Positive Characteristic

2016 ◽  
Vol 59 (3) ◽  
pp. 528-541 ◽  
Author(s):  
Qaiser Jahan
Keyword(s):  
Positive Characteristic ◽  
Sufficient Conditions ◽  
Local Fields ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Necessary And Sufficient ◽  
Low Pass Filters ◽  
The Scaling Function

AbstractIn this article, we give necessary and sufficient conditions on a function to be a low-pass filter on a local field K of positive characteristic associated with the scaling function for multiresolution analysis of L2(K). We use probability and martingale methods to provide such a characterization.

Fuzzy Logic Controller for Dynamic Positioning of an Offshore Supply Vessel

2017 ◽  
Author(s):  
Kunal N. Tiwari ◽  
Parameswaran Krishnankutty
Keyword(s):  
Fuzzy Logic Controller ◽  
Fuzzy Controller ◽  
Dynamic Positioning ◽  
Positioning System ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Dynamic Positioning System ◽  
Wave Disturbances ◽  
Control Scheme ◽  
Low Pass

The purpose of this paper is to examine the performance of fuzzy controller applied to a dynamic positioning system of ship by numerical simulation. By definition, dynamic positioning system is computer controlled system which uses the active thrusters to automatically maintain the position and heading of the ship. The proposed control scheme consist of low pass filter in cascade with three proportional derivative type fuzzy controller with Mamdani type inference scheme. Feed-forward compensation decoupling scheme is employed to reduce coupling between sway and yaw. Robustness of control scheme is assessed for Cybership II in presence of wave disturbances.

scholarly journals Adaptive anti-disturbance control for a class of unknown pure feedback switched nonlinear systems

2021 ◽  
Author(s):  
Longsheng Chen
Keyword(s):  
Nonlinear Systems ◽  
Design Method ◽  
Tracking Error ◽  
Average Dwell Time ◽  
Switched Nonlinear Systems ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Control Scheme ◽  
Low Pass ◽  
Set Up

Abstract In this study, an adaptive anti-disturbance control scheme is investigated for a class of unknown pure feedback switched nonlinear systems subjected to immeasurable states and external disturbances. Radial basis function neural networks (RBFNNs) are employed to identify the switched unknown nonlinearities, and a Butterworth low-pass filter is adopted to remove the algebraic loop problem. Subsequently, a novel switched neural state observer and a novel switched disturbance are presented via the coupled design method to estimate the immeasurable states and compounded disturbances. Then, an improved adaptive control strategy for the studied problem is designed with the help of a filtering method to eliminate the “explosion of complexity” problem, and certain compensating signals are set up to compensate for the filter errors, where switched updated laws are constructed to lessen the conservativeness caused by adoption of a common updated law for all subsystems. By utilizing the Lyapunov stability theorem, the developed control scheme can guarantee that all signals in the closed-loop system are bounded under a class of switching signals with the average dwell time (ADT), while the tracking error can converge to a small neighbourhood of origin. Finally, simulation results are provided to demonstrate the effectiveness of the presented approach.

Attitude Control for Ducted Fan UAV Based on Sliding Mode Adaptive Algorithm

2014 ◽  
Vol 513-517 ◽  
pp. 3915-3918
Author(s):  
Xiao Lu Ren ◽  
Chang Hong Wang ◽  
Guo Xing Yi
Keyword(s):  
Attitude Control ◽  
Control Method ◽  
Sliding Mode ◽  
Dynamic Performance ◽  
External Disturbance ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Ducted Fan ◽  
Multiple Input ◽  
Low Pass

According to the complicated condition and special dynamic performance of the Ducted Fan UAV, a nonlinear multiple input and multiple output control method is designed. This method is based on the sliding mode adaptive theory. Introducing the integral term, this method can work without the derivative value of the tracked signal; even the derivative doesnt exist or cannot be got. The adaptive control can identify the uncertain parameters and external disturbance, and adjust the controllers parameters real-time. Using a low-pass filter can effectively inhibit the chattering phenomenon in sliding mode control system. The Ducted Fan UAV attitude is controlled by this method. The simulation results show that this method has strong robustness and good tracking performance.

Discrete Sliding-Mode Tracking Control of High-Displacement Piezoelectric Actuator Systems

2004 ◽  
Vol 126 (4) ◽  
pp. 721-731 ◽  
Author(s):  
Chih-Lyang Hwang ◽  
Yung-Ming Chen
Keyword(s):  
Piezoelectric Actuator ◽  
Sliding Mode ◽  
External Disturbance ◽  
Recursive Least Squares ◽  
Tracking Accuracy ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Switching Surface ◽  
Low Pass ◽  
Band Limited

We consider the modeling and control of a high-displacement piezoelectric actuator system (HDPAS). An HDPAS includes a multilayer LVPZT bender actuator (MLBA) and a low-pass filter. The MLBA is subject to hysteresis, bending modes, measurement noise, and external disturbance. Because the spillover associated with a reduced-order model of the MLBA has been known to have the potential to cause the instability of the closed-loop system, a low-pass filter is applied to reduce its effect. To obtain an acceptable model for the HDPAS, a band-limited input and its corresponding output are fed into a recursive least-squares parameter estimation scheme. The resulting model is then used for a controller design, which includes three features. First, a dead-beat to its filtered switching surface is achieved. Second, the H∞ norm of the sensitivity function between the filtered switching surface and the output disturbance is simultaneously minimized to attenuate the effect of output disturbance. Third, a switching control based on Lyapunov redesign is used to further improve the tracking accuracy. To demonstrate the effectiveness of the proposed control, the experimental results of the HDPAS by using the proposed control are compared with those by a proportional integral differential (PID) control.

Design of Programmable Wideband Low Pass Filter with Continuous-Time/Discrete-Time Hybrid Architecture

2017 ◽  
Vol E100.C (10) ◽  
pp. 858-865 ◽  
Author(s):  
Yohei MORISHITA ◽  
Koichi MIZUNO ◽  
Junji SATO ◽  
Koji TAKINAMI ◽  
Kazuaki TAKAHASHI
Keyword(s):  
Discrete Time ◽  
Continuous Time ◽  
Hybrid Architecture ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass

ANALYSIS AND IMPROVEMENT TECHNIQUES FOR THE TRANSFER FUNCTION OF A PLANAR LOW - PASS FILTER

2016 ◽  
Vol 15 (12) ◽  
pp. 2579-2586
Author(s):  
Adina Racasan ◽  
Calin Munteanu ◽  
Vasile Topa ◽  
Claudia Pacurar ◽  
Claudia Hebedean
Keyword(s):  
Transfer Function ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass
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