負荷絞りをもつ空気圧伝送管路のステップ応答

抄録

This paper deals with the step response of throat-terminated pneumatic transmission lines. Analytical and experimental results are presented to show the reflection behaviour from a throat at the end of a line, and also to prove the dynamic matching technique.
The analysis is performed in the following steps;
(1) The transfer function of throat-terminated transmission lines is expanded in an infinite series in which the terms consist of the product of the reflection coefficient and the transfer function of semi-infinite line.
(2) With the assumption that the reflection coefficient (m) is constant, the step responses of throat-terminated lines based on the three analytical models of pneumatic transmission line, (i.e. lossless line model, linear friction model and Brown's model), are obtained. Then the model comparison is made on the basis of the calculated pressure waveforms for m=±1, ±0.5, 0.
(3) The pressure responses to a step input are calculated by using the Brown's model and the approximate reflection coefficients ma, ma =(RL-Rc)/(Rc+RL), Rc is the characteristic resistance of a line and RL the linearized load resistance due to the static characteristic of pressure-flowrate of a throat.
The experimental results with a positive pressure input are compared with the analytical results based on the Brown's model and ma. The agreement between experiment and calculated results is good. Therefore, it may be concluded that the response waveform of throatterminated lines to a step input can be forecated in the procedure described above and the practical matching condition is RL=Rc.