scholarly journals LPV Observer-Based Strategy for Rejection of Periodic Disturbances with Time-Varying Frequency

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
G. A. Ramos ◽  
Ramon Costa-Castelló ◽  
John Cortés-Romero
Keyword(s):  
Control Law ◽  
Periodic Signal ◽  
Test Bed ◽  
Linear Parameter Varying ◽  
Disturbance Estimation ◽  
Periodic Disturbances ◽  
Time Varying Frequency ◽  
Harmonic Decomposition ◽  
Disturbance Term ◽  
Resonant Control

Rejection of periodic disturbances is an important issue in control theory and engineering applications. Conventional strategies like repetitive control and resonant control can deal adequately with this problem but they fail when the frequency of the disturbance varies with time. This paper proposes a Linear Parameter Varying (LPV) resonant observer-based control for periodic signal rejection which is able to deal with the changes in frequency of the disturbance signal. The observer includes, in an embedded way, an internal model of the disturbance that is based on its harmonic decomposition. In this way, the frequency of the disturbance signal constitutes a parameter that can be adjusted according to the variations of the signal. The resulting disturbance estimation is then used by a control law that cancels the periodic disturbance term while controlling a specified tracking task. The proposed scheme lets the control designer address the disturbance estimation and tracking problems separately. Experimental results, on a mechatronic test bed, show that the proposed LPV resonant observer-based control successfully rejects periodic disturbances under varying frequency conditions.

scholarly journals Feedback Linearization Control of the Inertia Wheel Pendulum

2014 ◽  
Vol 14 (3) ◽  
pp. 96-109 ◽  
Author(s):  
Faculty of Automatics, Technical Un Enev
Keyword(s):  
Feedback Linearization ◽  
Wheel Speed ◽  
Control Law ◽  
Test Bed ◽  
Control Laws ◽  
Full State ◽  
Feedback Linearization Control ◽  
System Output ◽  
Inertia Wheel Pendulum ◽  
Definition Of

Abstract In this paper, two feedback linearizing control laws for the stabilization of the Inertia Wheel Pendulum are derived: a full-state linearizing controller, generalizing the existing results in literature, with friction ignored in the description and an inputoutput linearizing control law, based on a physically motivated definition of the system output. Experiments are carried out on a laboratory test bed with significant friction in order to test and verify the suggested performance and the results are presented and discussed. The main point to be made as a consequence of the experimental evaluation is the fact that actually the asymptotic stabilization was not achieved, but rather a limit cycling behavior was observed for the full-state linearizing controller. The input-output linearizing controller was able to drive the pendulum to the origin, with the wheel speed settling at a finite value

Robust Active Disturbance Rejection Control For Flexible Link Manipulator

Robotica ◽  
2019 ◽  
Vol 38 (1) ◽  
pp. 118-135 ◽  
Author(s):  
Raouf Fareh ◽  
Mohammad Al-Shabi ◽  
Maamar Bettayeb ◽  
Jawhar Ghommam
Keyword(s):  
Disturbance Rejection ◽  
Sliding Mode ◽  
Lyapunov Theory ◽  
Control Law ◽  
Active Disturbance Rejection Control ◽  
Flexible Link ◽  
Estimation Errors ◽  
Disturbance Estimation ◽  
Active Disturbance Rejection ◽  
Disturbance Rejection Control

SummaryThis paper presents an advanced robust active disturbance rejection control (ADRC) for flexible link manipulator (FLM) to track desired trajectories in the joint space and minimize the link’s vibrations. It has been shown that the ADRC technique has a very good disturbance rejection capability. Both the internal dynamics and the external disturbances can be estimated and compensated in real time. The proposed robust ADRC control law is developed to solve the problems existing in the original version of the ADRC related to the disturbance estimation errors and the variation of the parameters. Indeed, these parameters cannot be included in the existing disturbances and then be estimated by the extended state observer. The proposed control law is based on the sliding mode technique, which considers the uncertainties in the control gains and disturbance estimation errors. Lyapunov theory is used to prove the closed-loop stability of the system. The proposed control strategy is simulated and tested experimentally on one FLM. The effect of the observer bandwidth on the system performance is simulated and studied to select the best values of the bandwidth frequency. The simulation and experimental results show that the proposed robust ADRC has better performance than the traditional ADRC.

Output Feedback Linear Parameter Varying (LPV) L2-gain Control

2003 ◽  
Vol 125 (3) ◽  
pp. 485-489 ◽  
Author(s):  
Boe-S. Hong ◽  
Asok Ray ◽  
Vigor Yang
Keyword(s):  
Output Feedback ◽  
Gain Control ◽  
Control Law ◽  
Linear Parameter ◽  
Simulation Experiments ◽  
Linear Parameter Varying ◽  
Variation Rate ◽  
Parameter Varying ◽  
Mass Spring ◽  
L2 Gain

This brief paper synthesizes an output feedback L2-gain Control law for linear parameter varying (LPV) systems. The control law is embedded with an observer that does not require on-line measurements of the scheduling parameter variation rate. Results of simulation experiments are presented to evaluate the control law on a simulation experiments on a two-degree-of-freedom mass-spring-damper system.

Development of the HIDEC Inlet Integration Mode

1990 ◽  
Vol 112 (4) ◽  
pp. 565-572 ◽  
Author(s):  
J. D. Chisholm ◽  
S. G. Nobbs ◽  
J. F. Stewart
Keyword(s):  
Real Time ◽  
Control Mode ◽  
Control Law ◽  
Electronic Control ◽  
Test Bed ◽  
Integration System ◽  
Aircraft Performance ◽  
Integration Mode ◽  
Propulsion Control ◽  
Integration Concept

An integrated flight propulsion control mode called Inlet Integration has been developed and will be flight demonstrated on an F-15 test aircraft in the Highly Integrated Digital Electronic Control (HIDEC) program. The HIDEC program is conducted by the NASA Ames/Dryden Flight Research Center. The development of the Inlet Integration mode is described in this paper, including the Inlet Integration concept, the control law, its implementation on the test bed aircraft, and the predicted performance benefits. The Inlet Integration system will increase excess thrust (thrustdrag) during supersonic operation. This improvement in aircraft performance is accomplished by utilizing a calculation of engine corrected airflow from the Digital Electronic Engine Control (DEEC) to improve the scheduling of the inlet ramp positions in real time. The improvement in scheduled ramp positions will result in increased inlet performance, hence aircraft performance, while maintaining stable inlet operation. Analyses have shown the Inlet Integration system can increase excess thrust by as much as 13 percent at Mach 2.3, 40,000 ft. This thrust increase will result in increased supersonic acceleration. Inlet integration has the additional feature of improving aircraft supportability by eliminating the need for replacing inlet controllers when higher thrust derivative engines are installed in the F-15.

Asymptotic Rejection of Periodic Disturbances With Fixed or Varying Period

2000 ◽  
Vol 123 (3) ◽  
pp. 324-329 ◽  
Author(s):  
Shiang-Hwua Yu ◽  
Jwu-Sheng Hu
Keyword(s):  
Design Method ◽  
Repetitive Control ◽  
Sampling Interval ◽  
Control Law ◽  
Integer Multiple ◽  
Tuning Method ◽  
Periodic Disturbances ◽  
Optimal Delay ◽  
Close Relationship ◽  
Tuning Methods

A constructive derivation of repetitive control is obtained, through attempting to derive a control law for asymptotic rejection of periodic disturbances. This derivation not only reveals a close relationship between iterative operator inversion and repetitive control, but also suggests a unified design method for a learning control algorithm. Also, based on the observation, digital repetitive control can be generalized to reject periodic disturbance whose period is not exactly an integer multiple of the sampling interval. This study introduces a delay filter in the digital repetitive control law, which optimally interpolates the signal between samples, thus effectively reconstructing the signal of the previous period and making the learning process of repetitive control successful. The proposed optimal delay filter can be updated easily according to different signal periods. Thus it is specifically suitable for on-line tuning when the signal period is changing. Compared with the available tuning methods, the proposed tuning method has excellent steady-state performance while maintaining fast transient and system robustness. The simulations on active noise cancellation within a duct confirm the superiority of this tuning method.

Control law design for eliminating periodic disturbances above Nyquist frequency

2000 ◽  
Author(s):  
Richard Longman ◽  
Raphael Akogyeram ◽  
Jer-Nan Juang ◽  
Andrew Hutton
Keyword(s):  
Control Law ◽  
Nyquist Frequency ◽  
Periodic Disturbances

Disturbance Observer Based Tracking Control

1997 ◽  
Vol 122 (2) ◽  
pp. 332-335 ◽  
Author(s):  
Chia-Shang Liu ◽  
Huei Peng
Keyword(s):  
Tracking Control ◽  
Disturbance Observer ◽  
Control Algorithm ◽  
Sliding Mode ◽  
Correction Term ◽  
Superior Performance ◽  
Robot Arm ◽  
Disturbance Estimation ◽  
Control Scheme ◽  
Disturbance Term

A disturbance observer based tracking control algorithm is presented in this paper. The key idea of the proposed method is that the plant nonlinearities and parameter variations can be lumped into a disturbance term. The lumped disturbance signal is estimated based on a plant dynamic observer. A state observer then corrects the disturbance estimation in a two-step design. First, a Lyapunov-based feedback estimation law is used. The estimation is then improved by using a feedforward correction term. The control of a telescopic robot arm is used as an example system for the proposed algorithm. Simulation results comparing the proposed algorithm against a standard adaptive control scheme and a sliding mode control algorithm show that the proposed scheme achieves superior performance, especially when large external disturbances are present. [S0022-0434(00)00802-9]

Adaptive Rejection of Unmatched General Periodic Disturbances by Dynamic Output Feedback

2013 ◽  
Vol 710 ◽  
pp. 491-495
Author(s):  
Peng Nian Chen
Keyword(s):  
Output Feedback ◽  
Closed Loop ◽  
Output Feedback Control ◽  
Control Law ◽  
Dynamic Output Feedback ◽  
Time Varying ◽  
Closed Loop System ◽  
Periodic Disturbances ◽  
Adaptive Output Feedback Control ◽  
Coefficient Vector

The paper considers rejection of unmatched general periodic disturbances with time-varying gains for a class of nonlinear systems. The period of the periodic disturbances is known, the gains of the disturbances depend on the output of the system, and the coefficient vector of the disturbance input channel is not assumed to be a Hurwitz vector. A novel filtered transformation is presented. Based on the filtered transformation, an adaptive output feedback control law is proposed, which guarantees that the output of the closed loop system converges to zero.

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