Analytical research on a single degree-of-freedom semi-active oscillator with time delay

The primary and subharmonic resonances of a nonlinear single-degree-of-freedom system under feedback control with a time delay are studied by means of an asymptotic perturbation technique. Both external (forcing) and parametric excitations are included. By means of the averaging method and multiple scales method, two slow-flow equations for the amplitude and phase of the primary and subharmonic resonances and all other parameters are obtained. The steady state (fixed points) corresponding to a periodic motion of the starting system is investigated and frequency-response curves are shown. The stability of the fixed points is examined using the variational method. The effect of the feedback gains, the time-delay, the coefficient of cubic term, and the coefficients of external and parametric excitations on the steady-state responses are investigated and the results are presented as plots of the steady-state response amplitude versus the detuning parameter. The results obtained by two methods are in excellent agreement

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Loop Shaping for Transparency and Stability Robustness in Time-Delayed Bilateral Telemanipulation

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.1790539 ◽

2004 ◽

Vol 126 (3) ◽

pp. 650-656 ◽

Cited By ~ 10

Author(s):

Kevin B. Fite and ◽

Michael Goldfarb ◽

Angel Rubio

Keyword(s):

Time Delay ◽

Communication Channels ◽

Smith Predictor ◽

Degree Of Freedom ◽

Single Degree Of Freedom ◽

Single Degree ◽

Stability Robustness ◽

Loop Shaping ◽

And Performance ◽

Control Methodology

This paper presents a control methodology that provides transparency and stability robustness in bilateral telemanipulation systems that include a significant time delay in the communication channels. The method utilizes an adaptive Smith predictor to compensate for the time delay, and incorporates a previously published loop shaping approach to design a compensator for transparency and stability robustness of the loop. The method is experimentally demonstrated on a single degree-of-freedom telemanipulation system, and is shown to effectively provide stability and performance robustness.

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Optimization of PID controller parameters for active control of single degree of freedom structures

Challenge Journal of Structural Mechanics ◽

10.20528/cjsmec.2019.04.002 ◽

2019 ◽

Vol 5 (4) ◽

pp. 130

Author(s):

Serdar Ulusoy ◽

Sinan Melih Niğdeli ◽

Gebrail Bekdaş

Keyword(s):

Time Delay ◽

Active Control ◽

Pid Controller ◽

Structural Model ◽

Degree Of Freedom ◽

Control Force ◽

Single Degree Of Freedom ◽

Single Degree ◽

Near Fault ◽

Optimum Parameters

In active control of structures, the parameters of controllers used application must be perfectly tuned. In that case, a good vibration reduction performance can be obtained without a stability problem. During the tuning process, the limit of control force and time delay of controller system must be considered for applicable design. In the study, the optimum parameters of Proportional-Derivative-Integral (PID) type controllers that are proportional gain (K), integral time (Ti) and derivative time (Td) were optimized by using teaching learning-based optimization (TLBO). TLBO is a metaheuristic algorithm imitating the teaching and learning phases of education in classroom. The optimization was done according to the responses of the structure under a directivity pulse of near fault ground motions. In the study, time delay was considered as 20 ms and the optimum parameters of PID controller for a single degree of freedom (SDOF) structural model was found for different control force limits. The performances and feasibility of the method were evaluated by using sets of near fault earthquake records.

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