Application of the describing function technique in a single-loop feedback system with two nonlinearities

1968 ◽  
Vol 13 (2) ◽  
pp. 168-170 ◽  
Author(s):  
E. Davison
Keyword(s):  
Feedback System ◽  
Function Technique ◽  
Describing Function ◽  
Single Loop ◽  
Loop Feedback

THE INFLUENCE OF THE FEEDBACK STRUCTURE OF ADAPTIVE FRICTION INFLUENCE ON THE FORM OF CONTROL ACTION

2020 ◽  
Author(s):  
A.R. Lebedev ◽  
◽  
A.V. Ramzaev ◽  
Keyword(s):  
Frictional Contact ◽  
Feedback System ◽  
High Accuracy ◽  
Control Action ◽  
Friction Contact ◽  
Single Loop ◽  
Qualitative And Quantitative ◽  
Quantitative Estimates ◽  
Feedback Structure ◽  
Loop Feedback

It is shown that all three methods of achieving high accuracy of response are characterized by the corresponding feedback structure of adaptive friction contact. In a single-loop feedback system, the gain is variable, in double-circuit systems, its value is constant. The same type of feedback of adaptive frictional contact forms laws of change in the control action, independent of the type of gain, with similar qualitative and quantitative estimates.

Homeostatic capability of rate-sensitive feedback system: mathematical model

1984 ◽  
Vol 247 (5) ◽  
pp. R927-R931
Author(s):  
M. Okamoto ◽  
K. Hayashi
Keyword(s):  
Mathematical Model ◽  
Feedback Control ◽  
Feedback System ◽  
Control Element ◽  
External Perturbations ◽  
Large Loop ◽  
Key Enzyme ◽  
Loop Feedback ◽  
Control Capability ◽  
The Mathematical Model

We have predicted the mathematical model of rate-sensitive feedback control system and have investigated its homeostatic capability by using computer simulations. The results are summarized as follows. By installing a cyclic enzyme system as feedback control element, we could assume the rate-sensitive feedback system at molecular level. This type of feedback had realistic constant-value control capability for external perturbations. This feedback system was more effective for the exclusion of perturbation than was the concentration-sensitive feedback. A large-loop feedback was more stable for perturbation than was short-loop feedback. In sequential feedback system, every key enzyme sensitive to feedback control had to vary the activity at same time for the system to keep homeostasis.

Possible existence of a long-loop feedback system between FSH and inhibin in female rats

1981 ◽  
Vol 240 (5) ◽  
pp. E544-E549 ◽  
Author(s):  
L. V. DePaolo ◽  
L. D. Anderson ◽  
A. N. Hirshfield
Keyword(s):  
Follicle Stimulating Hormone ◽  
Feedback System ◽  
Female Rats ◽  
Time Interval ◽  
Ether Anesthesia ◽  
Peripheral Plasma ◽  
Loop Feedback ◽  
Ovarian Inhibin ◽  
Venous Plasma

Experiments were designed in which peripheral plasma inhibin levels were presumably altered in an attempt to investigate an interdependency between pituitary follicle-stimulating hormone (FSH) and ovarian inhibin secretion. In the first study, unilateral ovariectomy (ULO) was performed on 4-day cycling female rats under ether anesthesia at 0800 h on diestrous day 1 (D1). Inhibin-like activity [FSH-inhibiting activity(FSH-IA)] in untreated ovarian venous plasma (OVP) collected from the remaining ovary was assessed by an in vitro pituitary bioassay system. Both plasma FSH levels and FSH-IA significantly increased between 4 and 12 h after ULO. Thereafter, plasma FSH declined between 12 and 32 h after ULO, whereas FSH-IA remained elevated during this same time interval. Compared to sham-operated rats, plasma FSH was significantly elevated 4, 12, and 24 h after ULO, whereas FSH-IA was statistically higher only at 32 h after ULO. In a second experiment, rats were injected with charcoal-treated porcine follicular fluid (PFF) on proestrus and estrus. Control rats received saline. The data indicate that increased plasma FSH levels on D1 in PFF-treated rats (FSH rebound) may be a consequence of reduced endogenous inhibin secretion on estrus. As well, return of FSH to control levels on D2 in PFF-treated rats may have resulted from an FSH-associated increase in FSH-IA on D1 and D2.

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