Subsynchronous Resonance Mitigation for Series-Compensated DFIG-Based Wind Farm by Using Two-Degree-of-Freedom Control Strategy

2015 ◽  
Vol 30 (3) ◽  
pp. 1442-1454 ◽  
Author(s):  
Po-Hsu Huang ◽  
Mohamed Shawky El Moursi ◽  
Weidong Xiao ◽  
James L Kirtley
Keyword(s):  
Control Strategy ◽  
Wind Farm ◽  
Degree Of Freedom ◽  
Subsynchronous Resonance ◽  
Two Degree Of Freedom

scholarly journals Control of Near-Grazing Dynamics in the Two-Degree-of-Freedom Vibroimpact System with Symmetrical Constraints

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zihan Wang ◽  
Jieqiong Xu ◽  
Shuai Wu ◽  
Quan Yuan
Keyword(s):  
Control Strategy ◽  
Stability Criterion ◽  
Control Method ◽  
Degree Of Freedom ◽  
Local Analysis ◽  
Grazing Bifurcation ◽  
Vibroimpact System ◽  
The Stability ◽  
Two Parameters ◽  
Two Degree Of Freedom

The stability of grazing bifurcation is lost in three ways through the local analysis of the near-grazing dynamics using the classical concept of discontinuity mappings in the two-degree-of-freedom vibroimpact system with symmetrical constraints. For this instability problem, a control strategy for the stability of grazing bifurcation is presented by controlling the persistence of local attractors near the grazing trajectory in this vibroimpact system with symmetrical constraints. Discrete-in-time feedback controllers designed on two Poincare sections are employed to retain the existence of an attractor near the grazing trajectory. The implementation relies on the stability criterion under which a local attractor persists near a grazing trajectory. Based on the stability criterion, the control region of the two parameters is obtained and the control strategy for the persistence of near-grazing attractors is designed accordingly. Especially, the chaos near codimension-two grazing bifurcation points was controlled by the control strategy. In the end, the results of numerical simulation are used to verify the feasibility of the control method.

Two degree-of-freedom design for a send-on-delta sampling PI control strategy

2014 ◽  
Vol 30 ◽  
pp. 55-66 ◽  
Author(s):  
M. Beschi ◽  
S. Dormido ◽  
J. Sánchez ◽  
A. Visioli
Keyword(s):  
Control Strategy ◽  
Degree Of Freedom ◽  
Pi Control ◽  
Two Degree Of Freedom

Endoscope Geometrical Analysis and Kinematic Control

2007 ◽  
Author(s):  
Harvey Lipkin ◽  
Jomkwun Munnae ◽  
Gary McMurray ◽  
Debao Zhou ◽  
Wayne Daley
Keyword(s):  
Minimally Invasive ◽  
Medical Practice ◽  
Control Strategy ◽  
Degree Of Freedom ◽  
Geometrical Analysis ◽  
Efficient Manner ◽  
Kinematic Control ◽  
Serial Robot ◽  
Invasive Diagnostics ◽  
Two Degree Of Freedom

Endoscopes are used in medical practice to effect minimally invasive diagnostics and treatments through a natural or surgical orifice. The endoscope is a snakelike device with a two degree-of-freedom articulated tip that bends in any direction using internal cables actuated by knobs. In this paper we use a serial robot model of the tip to show that the tip motions are not decoupled with respect to the knob inputs nor do they have constant gains. Further in a geometrical analysis it is shown that the articulated tip always lies along a circle. A tip kinematic control strategy is developed based on small motions that is able to decouple the output motions from the input motions and provide a constant gain functions. This allows the surgeon to control the endoscope in an intuitive and efficient manner.

Two Degree-of-Freedom Hysteresis Compensation for a Dynamic Mirror With Antagonistic Piezoelectric Stack Actuation

2013 ◽  
Author(s):  
James A. Mynderse ◽  
George T. C. Chiu
Keyword(s):  
Input Signal ◽  
Control Strategy ◽  
Closed Loop ◽  
Loop System ◽  
Degree Of Freedom ◽  
Closed Loop System ◽  
Loop Control ◽  
Hysteresis Compensation ◽  
Hysteresis Control ◽  
Two Degree Of Freedom

A methodology for designing a low-computation, high-bandwidth strategy for closed-loop control of a hysteretic system without a priori knowledge of the desired trajectory is presented. The resulting two degree-of-freedom hysteresis control strategy is applied to a dynamic mirror with antagonistic piezoelectric stack actuation. Hysteresis compensator is performed by a finite state machine switching polynomials for hysteresis inversion based on the input signal slope. Residual error after hysteresis compensation is corrected by an LQR feedback controller. Experimental results demonstrate effectiveness of the hysteresis compensator and closed-loop system under the proposed hysteresis control strategy. For the triangular input signal tested, the closed-loop system achieves a 91.5% reduction in hysteresis uncertainty with 60 kHz sample rate.

scholarly journals Fault-tolerant control strategy for actuator faults using LPV techniques: Application to a two degree of freedom helicopter

2012 ◽  
Vol 22 (1) ◽  
pp. 161-171 ◽  
Author(s):  
Saúl de Oca ◽  
Vicenç Puig ◽  
Marcin Witczak ◽  
Łukasz Dziekan
Keyword(s):  
Control Strategy ◽  
Fault Tolerant ◽  
Design Procedure ◽  
Fault Tolerant Control ◽  
Degree Of Freedom ◽  
Fault Identification ◽  
Linear Matrix ◽  
Actuator Faults ◽  
Control Schemes ◽  
Two Degree Of Freedom

Fault-tolerant control strategy for actuator faults using LPV techniques: Application to a two degree of freedom helicopter In this paper, a Fault Tolerant Control (FTC) strategy for Linear Parameter Varying (LPV) systems that can be used in the case of actuator faults is proposed. The idea of this FTC method is to adapt the faulty plant instead of adapting the controller to the faulty plant. This approach can be seen as a kind of virtual actuator. An integrated FTC design procedure for the fault identification and fault-tolerant control schemes using LPV techniques is provided as well. Fault identification is based on the use of an Unknown Input Observer (UIO). The FTC controller is implemented as a state feedback controller and designed using polytopic LPV techniques and Linear Matrix Inequality (LMI) regions in such a way as to guarantee the closed-loop behavior in terms of several LMI constraints. To assess the performance of the proposed approach, a two degree of freedom helicopter is used.

scholarly journals Modified two-degree-of-freedom Smith predictive control for processes with time-delay

2020 ◽  
Vol 53 (3-4) ◽  
pp. 691-697 ◽  
Author(s):  
Ziwei Li ◽  
Jianjun Bai ◽  
Hongbo Zou
Keyword(s):  
Time Delay ◽  
Predictive Control ◽  
Control Strategy ◽  
Disturbance Rejection ◽  
Control Method ◽  
Internal Model Control ◽  
Degree Of Freedom ◽  
Set Point ◽  
Point Tracking ◽  
Two Degree Of Freedom

This article proposes an improved two-degree-of-freedom Smith predictive control method for typical industrial control systems. Smith predictive control is a classic control strategy designed for systems with pure lag. As an extension of Smith predictive control, internal model control can solve the time-delay problem effectively and make the controller design simple. Based on the two control algorithms, an enhanced control method with modified control structure is developed in this paper. In the design scheme, the set-point tracking and the disturbance rejection characteristics are decoupled, such that the set-point tracking and disturbance rejection controllers can be designed independently to achieve better control performance. The obtained control strategy possesses simple and convenient parameter tuning procedures. The validity of the proposed scheme is verified through theoretical analysis and simulation comparison with other control methods, and the results indicate that the proposed strategy shows better performance on set-point tracking and disturbance rejection.

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