scholarly journals Research on Improved Adaptive Control for Static Synchronous Compensator in Power System

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Chao Zhang ◽  
Aimin Zhang ◽  
Hang Zhang ◽  
Yingsan Geng ◽  
Yunfei Bai
Keyword(s):  
Adaptive Control ◽  
Transient Stability ◽  
Estimation Error ◽  
Adaptive Controller ◽  
Uncertain Parameter ◽  
Static Synchronous Compensator ◽  
Dynamic Surface ◽  
Pass Filter ◽  
Low Pass Filter ◽  
System States

This paper deals with the problems of “explosion of term,” uncertain parameter in static synchronous compensator (STATCOM) system with nonlinear time-delay. An improved adaptive controller is proposed to enhance the transient stability of system states and reduce computational complexity of STATCOM control system. In contrast to backstepping control scheme in high order systems, the problem of “explosion of term” is avoided by designing dynamic surface controller. The low pass filter is included to allow a design where the model is not differentiated and thus has prevented the mathematical complexities effectively. In addition, unlike the traditional adaptive control schemes, the certainty equivalence principle is not required for estimating the uncertain parameter by system immersion and manifold invariant (I&I) adaptive control. A smooth function is added to ensure that the estimation error converges to zero in finite time. The effectiveness of the proposed controller is verified by the simulations. Compared with adaptive backstepping and proportion integration differentiation (PID), the oscillation amplitudes of transient response are reduced by nearly half, and the time of reaching steady state is shortened by at least 11%.

scholarly journals Neural NetworkL1Adaptive Control of MIMO Systems with Nonlinear Uncertainty

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Hong-tao Zhen ◽  
Xiao-hui Qi ◽  
Jie Li ◽  
Qing-min Tian
Keyword(s):  
Mimo Systems ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Adaptive Controller ◽  
Rbf Neural Networks ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Input Multiple Output ◽  
Low Pass ◽  
Nonlinear Uncertainties

An indirect adaptive controller is developed for a class of multiple-input multiple-output (MIMO) nonlinear systems with unknown uncertainties. This control system is comprised of anL1adaptive controller and an auxiliary neural network (NN) compensation controller. TheL1adaptive controller has guaranteed transient response in addition to stable tracking. In this architecture, a low-pass filter is adopted to guarantee fast adaptive rate without generating high-frequency oscillations in control signals. The auxiliary compensation controller is designed to approximate the unknown nonlinear functions by MIMO RBF neural networks to suppress the influence of uncertainties. NN weights are tuned on-line with no prior training and the project operator ensures the weights bounded. The global stability of the closed-system is derived based on the Lyapunov function. Numerical simulations of an MIMO system coupled with nonlinear uncertainties are used to illustrate the practical potential of our theoretical results.

scholarly journals A fast L1 adaptive constrained back-stepping controller using barrier Lyapunov function for anuncertain submersible vehicle

2021 ◽  
Author(s):  
Hossein Ahmadian ◽  
Mehdi Arefi ◽  
Alireza Khayatian ◽  
Allahyar Montazeri
Keyword(s):  
Adaptive Control ◽  
Lyapunov Function ◽  
Trajectory Tracking ◽  
Tracking Error ◽  
Control Technique ◽  
Remotely Operated Vehicle ◽  
Pass Filter ◽  
Low Pass Filter ◽  
L1 Adaptive Control ◽  
Barrier Lyapunov Function

Abstract In this paper, a new L1 adaptive back-stepping controller based on the barrier Lyapunov function (BLF) is proposed to respect the position and velocity constraints usually imposed in designing Euler-Lagrange systems. The purpose of this investigation is to improve different aspects of a conventional L1 adaptive control. More specifically, the modified controller has a lower complexity by removing the low-pass filter from the design procedure. The performance of the controller is also enhanced by having a faster convergence speed and increased robustness against nonlinear uncertainties and disturbances arising in practical applications. The proposed scheme is evaluated on two different Euler-Lagrange systems, i.e. a 6-DOF remotely operated vehicle (ROV) and a single-link manipulator. The results for the new back-stepping design are assessed in both scenarios in terms of settling time, percentage of overshoot, and trajectory tracking error. The results confirm that both tracking and state estimation errors for position and velocity outputs outperform the standard L1 adaptive control technique. The results also demonstrate the high performance of the proposed approach in removing the matched nonlinear time-varying disturbances and dynamic uncertainties and a good trajectory tracking despite the uncertainty on the input gain of the system.

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 Dynamic Compensator-Based Output Feedback Controller Design for Uncertain Systems with Adjustable Robustness

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Jeang-Lin Chang ◽  
Tsui-Chou Wu
Keyword(s):  
Output Feedback ◽  
Controller Design ◽  
Mimo Systems ◽  
Input Saturation ◽  
Feedback Stabilization ◽  
Pass Filter ◽  
Low Pass Filter ◽  
System States ◽  
Filter Property ◽  
Uniformly Ultimate Boundedness

A low-order dynamics compensator-based output feedback stabilization method for a class of uncertain linear MIMO systems with mismatched disturbances is presented. Since all the system states are not measurable, the proposed controller inherently has low-pass filter property in which it can successfully replace the derivative terms of the system output and hence effectively estimate the input disturbance. The control scheme proposed here can simultaneously consider the input saturation problem and obtain the desired performance. Although the system has unknown uncertainties and disturbances, the uniformly ultimate boundedness of system states in the closed-loop system is analytically shown using the Lyapunov method. Finally, two numerical examples are presented to demonstrate the applicability of the proposed scheme.

scholarly journals Dynamic Surface Control and Its Application to Lateral Vehicle Control

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Bongsob Song ◽  
J. Karl Hedrick ◽  
Yeonsik Kang
Keyword(s):  
Nonlinear Systems ◽  
Dynamic Surface Control ◽  
Vehicle Control ◽  
Linear Matrix ◽  
Automated Driving ◽  
Dynamic Surface ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Surface Control ◽  
Highly Nonlinear

This paper extends the design and analysis methodology of dynamic surface control (DSC) in Song and Hedrick, 2011, for a more general class of nonlinear systems. When rotational mechanical systems such as lateral vehicle control and robot control are considered for applications, sinusoidal functions are easily included in the equation of motions. If such a sinusoidal function is used as a forcing term for DSC, the stability analysis faces the difficulty due to highly nonlinear functions resulting from the low-pass filter dynamics. With modification of input variables to the filter dynamics, the burden of mathematical analysis can be reduced and stability conditions in linear matrix inequality form to guarantee the quadratic stability via DSC are derived for the given class of nonlinear systems. Finally, the proposed design and analysis approach are applied to lateral vehicle control for forward automated driving and backward parallel parking at a low speed as well as an illustrative example.

A study of PID and L1 adaptive control for automatic balancing of a spacecraft three-axis simulator

2018 ◽  
Vol 11 (2) ◽  
pp. 269-284
Author(s):  
Bing Hua ◽  
Lin Chen ◽  
Yunhua Wu ◽  
Zhiming Chen
Keyword(s):  
Adaptive Control ◽  
Control Method ◽  
Large Angle ◽  
High Frequency Signal ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Content Type ◽  
L1 Adaptive Control ◽  
Automatic Balancing ◽  
Disturbance Torque

Purpose The three-axis simulator relies on the air film between the air bearing and the bearing seat to achieve weightlessness and the frictionless motion condition, which is essential for simulating the micro-disturbance torque of a satellite in outer space. However, at the beginning of the experiment, the disturbance torque caused by the misalignment between the center of gravity of the simulator and the center of rotation of the bearing is the most important factor restricting the use of the space three-axis simulator. In order to solve this problem, it is necessary to set the balance adjustment system on the simulator to compensate the disturbance torque caused by the eccentricity. The paper aims to discuss these issues. Design/methodology/approach In this paper, a study of L1 adaptive automatic balancing control method for micro satellite with motor without other actuators is proposed. L1 adaptive control algorithm adds the low-pass filter to the control law, which in a certain sense to reduce the high-frequency signal and speed up the response time of the controlled system. At the same time, by estimating the adaptive parameter uncertainty in object, the output error of the state predictor and the controlled object can be stabilized under Lyapunov condition, and the robustness of the system is also improved. The automatic balancing method of PID is also studied in this paper. Findings Through this automatic balancing mechanism, the gravity disturbance torque can be effectively reduced down to 10−6 Nm, and the automatic balancing time can be controlled within 7 s. Originality/value This paper introduces an automatic balancing mechanism. The experimental results show that the mechanism can greatly improve the convergence speed while guaranteeing the control accuracy, and ensuring the feasibility of the large angle maneuver of spacecraft three-axis simulator.

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.

scholarly journals Performance Evaluation of Stewart-Gough Flight Simulator Based on L1 Adaptive Control

2021 ◽  
Vol 11 (7) ◽  
pp. 3288
Author(s):  
Jiangwei Zhao ◽  
Dongsu Wu ◽  
Hongbin Gu
Keyword(s):  
Adaptive Controller ◽  
Simulation System ◽  
Flight Simulation ◽  
Flight Simulator ◽  
Transient Performance ◽  
Pass Filter ◽  
Low Pass Filter ◽  
L1 Adaptive Control ◽  
Highly Nonlinear ◽  
L1 Adaptive Controller

In the design of the six degrees of freedom (6-DOF) flight simulation system, the unmodeled dynamic, transient performance and steady-state performance of the system are generally concerned. Considering that the model of flight simulation system is highly nonlinear and requires high response speed and high stability, this paper applies L1 adaptive controller to the control of flight simulation platform. The controller has a low-pass filter in feedback loop to avoid high frequencies in the control signals, and the required transient performance can be enhanced by increasing the adaptive gain, which can improve the transient, stability, and smoothness of the flight simulator platform. The performance of the L1 adaptive controller is obtained by comparison with the traditional model reference adaptive controller (MRAC). In addition to maintaining the good transient response of MRAC, the L1 adaptive controller improves the stability of the system. The output amplitude of the actuator is reduced by 39.95%, which effectively reduces the performance requirements of the actuator. Some additional experimental evaluations are carried out to show the performance of the controller.

scholarly journals The Investigation on L 1 Adaptive Control of the Tilt-Rotor Aircraft

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Quanlong Chen ◽  
Shanyong Zhao ◽  
Ke Lu ◽  
Senkui Lu ◽  
Chunsheng Liu ◽  
...  
Keyword(s):  
Control System ◽  
Adaptive Design ◽  
Reference Signal ◽  
Engineering Application ◽  
Adaptive Controller ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Tilt Rotor ◽  
Conversion Mode ◽  
Flight Dynamics Model

Considering the uncertainty of the flight dynamics model of the tilt-rotor aircraft in different flight modes, an L 1 adaptive controller for full flight modes control system of tilt-rotor aircraft is designed. Taking advantage of the separation of robustness and adaptive design of the L 1 adaptive controller, adaptive gain, and low-pass filter are designed to achieve the desired control performance and meet the requirements of flight quality. The simulations of XV-15 tilt-rotor aircraft in helicopter mode and airplane mode are carried out. Then, the simulation of conversion mode is further carried out. The results show that the tilt-rotor aircraft can track the reference signal well under the L 1 control system. In addition, the changes of states as well as controls in conversion mode flight are quite smooth which is very meaningful for engineering application.

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