Abstract
In this report, the mechanism of automatic level control system for product sliver is described. The variation of product sliver's thickness is measured by air-micrometer.
The appearance of this air-micro-nozzle is same as that of the conventional trumpet and this nozzle is set on the front side of the delivery roller. The transmitting loop of signal is as follows: air-micro nozzle (measuring the variation of thickness of product sliver)→bellows→Record pet→electric switch (with limit of adress)→relay→pilot motor→speed regulater→draft change gear train→feed roller (or delivery roller).
The conculusion of this analysis is as follows;
(1) Transfer function of this control loop G(s) is where, kn=2B√4a2-Δ2/πa2, Y0: average thickness of feed sliver, V1: surface speed of delivery roller, L=τ1+τ2, τ1: dead time in draft zone, τ2: dead time between front nip point and airmicro nozzle (trumpet), kn: transfer function of electric circuit which has the non-linear characteristics with limit of adress (range Δ), a sin ωt: input of electric circuit, k1: gain constant of air micro nozzle, km: gain constant of speed regulator and gear train of draft change, K; gain conctant of sensing device, B; voltage of pilot motor, Tm; time constant of speed regulater and gear train of draft change, T; time constant of sensing device.
(2) This control system meets with the stability criterion of NYQUIST in the conventional and so-called high speed of delivery roller.
(3) By using Toka's definition of residual variation of thickness of product sliver, the effect of automatic control is discussed.
Definition of residual variation of thickness of product sliver E % is as follows;
where, X0 is average thickness of product sliver., X(s) and Y(s) notation of laplace transformation for x(t) (variation of thickness of product sliver) and y(t) (variation of thickness of feed sliver). In this control system, E is caluculated by the following equation.
The theoretical conclusion of this analysis, shows close resemblance with actual data and good effect of control is expected for domain of long term variation (more than 3 meter) of product sliver's thickness.
(4) By the theoretical analysis of frequency response by Bode diagram, the effect of delivery roller's surface-speed is discussed, and author shows the close resemblance on frequency response betwen conventinal speed and so-called high speed of the delivery roller.
