Frequency-Domain Vibration Control of Distributed Gyroscopic Systems

1991 ◽  
Vol 113 (1) ◽  
pp. 18-25 ◽  
Author(s):  
B. Yang ◽  
C. D. Mote
Keyword(s):  
Vibration Control ◽  
Closed Loop ◽  
Loop System ◽  
System Stability ◽  
Root Locus ◽  
Closed Loop System ◽  
Locus Method ◽  
Nyquist Criterion ◽  
Actuation Devices ◽  
Gyroscopic Systems

A new method is presented for vibration control of distributed gyroscopic systems. The control is formulated in the Laplace transform domain. The transfer function of a closed-loop system, consisting of the plant, a feedback control law and the dynamics of the sensing and actuation devices, is derived. Stability analyses of the closed-loop system use both the root locus method and the generalized Nyquist criterion. Two stability criteria are obtained. Design of stabilizing controllers is carried out for both colocation and noncolocation of the sensor and actuator. The effects of time-delay and noncolocation of the sensor and actuator on the system stability are analyzed. In addition, the relationship between the root locus method and the generalized Nyquist criterion is discussed.

PI Control of HSFDs for Active Control of Rotor-Bearing Systems

1997 ◽  
Vol 119 (3) ◽  
pp. 658-667 ◽  
Author(s):  
J. P. Hathout ◽  
A. El-Shafei
Keyword(s):  
Vibration Control ◽  
Active Control ◽  
Closed Loop ◽  
Rotating Machinery ◽  
Loop System ◽  
Pi Control ◽  
Closed Loop System ◽  
Transient Vibration ◽  
Critical Speeds ◽  
Rotor Bearing

This paper describes the proportional integral (PI) control of hybrid squeeze film dampers (HSFDS) for active control of rotor vibrations. Recently it was shown that the automatically controlled HSFD based on feedback of rotor speed can be a very efficient device for active control of rotor vibration when passing through critical speeds. Although considerable effort has been put into the study of steady-state vibration control, there are few methods in the literature applicable to transient vibration control of rotor-bearing systems. Rotating machinery may experience dangerously high dynamic loading due to the sudden mass unbalance that could be associated with blade loss. Transient run-up and coast down through critical speeds when starting up or shutting down rotating machinery induces excessive bearing loads at criticals. In this paper, PI control is proposed as a regulator for the HSFD system to attenuate transient vibration for both sudden unbalance and transient runup through critical speeds. A complete mathematical model of this closed-loop system is simulated on a digital computer. Results show an overall enhanced behavior for the closed-loop rotor system. Gain scheduling of both the integral gain and the reference input is incorporated into the closed-loop system with the PI regulator and results in an enhanced behavior of the controlled system.

scholarly journals Robust LFC Strategy for Wind Integrated Time-Delay Power System Using EID Compensation

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3223 ◽  
Author(s):  
Liu ◽  
Zhang ◽  
Zou
Keyword(s):  
Time Delay ◽  
Power System ◽  
Closed Loop ◽  
Frequency Control ◽  
Loop System ◽  
Load Frequency Control ◽  
System Stability ◽  
Linear Matrix ◽  
Closed Loop System ◽  
The Stability

This paper presents an active disturbance rejection control (ADRC) technique for load frequency control of a wind integrated power system when communication delays are considered. To improve the stability of frequency control, equivalent input disturbances (EID) compensation is used to eliminate the influence of the load variation. In wind integrated power systems, two area controllers are designed to guarantee the stability of the overall closed-loop system. First, a simplified frequency response model of the wind integrated time-delay power system was established. Then the state-space model of the closed-loop system was built by employing state observers. The system stability conditions and controller parameters can be solved by some linear matrix inequalities (LMIs) forms. Finally, the case studies were tested using MATLAB/SIMULINK software and the simulation results show its robustness and effectiveness to maintain power-system stability.

Robust attitude fault-tolerant control for unmanned autonomous helicopter with flapping dynamics and actuator faults

2018 ◽  
Vol 41 (5) ◽  
pp. 1266-1277 ◽  
Author(s):  
Kun Yan ◽  
Mou Chen ◽  
Qiangxian Wu ◽  
Ke Lu
Keyword(s):  
Closed Loop ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Loop System ◽  
System Stability ◽  
Actuator Faults ◽  
Closed Loop System ◽  
Attitude Tracking ◽  
Control Scheme ◽  
Autonomous Helicopter

In this paper, an adaptive robust fault-tolerant control scheme is developed for attitude tracking control of a medium-scale unmanned autonomous helicopter with rotor flapping dynamics, external unknown disturbances and actuator faults. For the convenience of control design, the actuator dynamics with respect to the tail rotor are introduced. The adaptive fault observer and robust item are employed to observe the actuator faults and eliminate the effect of external disturbances, respectively. A backstepping-based robust fault-tolerant control scheme is designed with the aim of obtaining satisfactory tracking performance and closed-loop system stability is proved via Lyapunov analysis, which guarantees the convergence of all closed-loop system signals. Simulation results are given to show the effectiveness of the proposed control method.

scholarly journals High Efficient Solar Integrated an Isolated Dc-Dc Full-Bridge Converter for Electric Vehicle Battery Charging Application

2020 ◽  
Vol 9 (4) ◽  
pp. 432-437
Keyword(s):  
Electric Vehicle ◽  
Closed Loop ◽  
Open Loop ◽  
Loop System ◽  
System Stability ◽  
Control Technique ◽  
Closed Loop System ◽  
Conductance Method ◽  
High Efficient ◽  
Electric Vehicle Battery

In this paper, the power from a solar PV panel 20VDC, 12.5ADC is used for charging an electric vehicle battery (12V, 7Ah) with the help of an isolated dc-dc converter in an efficient manner. The power rating maintained in the system is around (200-250) W. The parasitic circuit analysis is carried out theoretically. The zero voltage transition (ZVT) technique is implemented at the inverter stage and an isolation transformer (1:1) is used for source-load isolation purposes. In order to achieve ZVT, a proper design procedure is followed and a pulse triggering technique is carried out at the switching element. The designed values of the parasitic elements are used in the Simulink tool. The open loop and closed loop system of the proposed converter are simulated in MATLAB Simulink package. In the open loop system, an irradiation analysis carried out similarly closed loop has reference voltage variation analysis in order to verify the system stability at the various operating condition. The problem of transients in open loop output is rectified in the closed loop operation. The MPP and PI control technique is initiated in the closed loop system for better performance. The MPP technique used is incremental conductance method for tracking maximum power from the PV array.

Multi Observer-Based Sliding Mode Load Frequency Control With Input Delay Estimation

2021 ◽  
Vol 1 (4) ◽  
Author(s):  
Ark Dev ◽  
David Fernando Novella Rodríguez ◽  
Sumant Anand ◽  
Mrinal Kanti Sarkar
Keyword(s):  
Power Systems ◽  
Closed Loop ◽  
Sliding Mode ◽  
Time Delay Estimation ◽  
Loop System ◽  
Load Frequency Control ◽  
System Stability ◽  
Input Delay ◽  
Delay Estimation ◽  
Closed Loop System

Abstract The letter proposes frequency stability in power systems with input delay. A closed loop system can be oscillatory or even unstable without the exact knowledge of delay. Therefore, it is desirable to design a control scheme which is based on the estimation of unknown delay. The proposed design consists of an infinite dimensional observer with an adaptive time delay estimation and a sliding mode controller (SMC). The merit of the proposed concept lies in the fact that the unknown delay is valued by just estimating the smallest delay segment. The controller input is obtained from a set of sequential observers that predicts the system states and ensures asymptotic stability of the closed loop system with input delay estimation. The existence of sliding mode and the closed loop system stability is proved thanks to the Lyapunov and Lyapunov–Krasovskii candidate functionals, respectively. Simulation results confirm the effectiveness of the proposed design.

scholarly journals PI Control of HSFDs for Active Control of Rotor-Bearing Systems

1996 ◽  
Author(s):  
J. P. Hathout ◽  
A. El-Shafei
Keyword(s):  
Vibration Control ◽  
Active Control ◽  
Closed Loop ◽  
Rotating Machinery ◽  
Loop System ◽  
Pi Control ◽  
Closed Loop System ◽  
Transient Vibration ◽  
Critical Speeds ◽  
Run Up

This paper describes the proportional integral (PI) control of hybrid squeeze film dampers (HSFDs) for active control of vibrations of rotors. Recently it was shown that the automatically controlled HSFD based on feedback of rotor speed can be a very efficient device for active control of rotor vibration when passing through critical speeds. Although considerable effort has been put into the study of steady state vibration control, there are few methods in the literature applicable to transient vibration control of rotor-bearing systems. Rotating machinery may experience dangerously high dynamic loading due to the sudden mass unbalance that could be associated with blade loss. Transient run-up and coast down through critical speeds when starting up or shutting down rotating machinery induces excessive bearing loads at criticals. In this paper, PI control is proposed as a regulator for the HSFD system to attenuate transient vibration for both sudden unbalance and transient run-up through critical speeds. A complete mathematical model of this closed-loop system is simulated on a digital computer. Results show an overall enhanced behavior for the closed-loop rotor system. Gain scheduling of both the integral gain and the reference input is incorporated to the closed-loop system with the PI regulator and results in an enhanced behavior of the controlled system.

Sensitivity Comparison to Loop Latencies Between Damping Versus Stiffness Feedback Control Action in Distributed Controllers

2014 ◽  
Author(s):  
Ye Zhao ◽  
Nicholas Paine ◽  
Luis Sentis
Keyword(s):  
Closed Loop ◽  
Impedance Control ◽  
Tracking Error ◽  
Loop System ◽  
Tracking Performance ◽  
System Stability ◽  
Step Response ◽  
Tracking Accuracy ◽  
Closed Loop System ◽  
And Performance

This paper studies the effects of damping and stiffness feedback loop latencies on closed-loop system stability and performance. Phase margin stability analysis, step response performance and tracking accuracy are respectively simulated for a rigid actuator with impedance control. Both system stability and tracking performance are more sensitive to damping feedback than stiffness feedback latencies. Several comparative tests are simulated and experimentally implemented on a real-world actuator to verify our conclusion. This discrepancy in sensitivity motivates the necessity of implementing embedded damping, in which damping feedback is implemented locally at the low level joint controller. A direct benefit of this distributed impedance control strategy is the enhancement of closed-loop system stability. Using this strategy, feedback effort and thus closed-loop actuator impedance may be increased beyond the levels possible for a monolithic impedance controller. High impedance is desirable to minimize tracking error in the presence of disturbances. Specially, trajectory tracking accuracy is tested by a fast swing and a slow stance motion of a knee joint emulating NASA-JSC’s Valkyrie legged robot. When damping latencies are lowered beyond stiffness latencies, gravitational disturbance is rejected, thus demonstrating the accurate tracking performance enabled by a distributed impedance controller.

scholarly journals Active Vibration Control of PID Based on Receptance Method

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Lijuan Peng ◽  
Jian Wang ◽  
Guicheng Yu ◽  
Zuoxue Wang ◽  
Aijun Yin ◽  
...  
Keyword(s):  
Vibration Control ◽  
Closed Loop ◽  
Damping Ratio ◽  
Active Vibration Control ◽  
Loop System ◽  
Closed Loop System ◽  
Integral Control ◽  
Active Vibration ◽  
Receptance Method ◽  
Poles And Zeros

Active vibration control approaches have been widely applied on improving reliability of robotic systems. For linear vibratory systems, the vibration features can be altered by modifying poles and zeros. To realize the arbitrary assignment of the closed-loop system poles and zeros of a linear vibratory system, in this paper, an active PID input feedback vibration control method is proposed based on the receptance method. The establishment and verification of the proposed method are demonstrated. The assignable poles during feedback control are calculated and attached with importance to expand the application of the integral control. Numerical simulations are conducted to verify the validity of the proposed method in terms of the assignment of closed-loop poles, zeros, and both. The results indicate that the proposed method can be used to realize the active vibration control of closed-loop system and obtain the desired damping ratio, modal frequency, and dynamic response.

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