Abstract
This paper is concerned with the transfer characteristics of a pneumatic micrometer system with a positive feedback transducer. The system has two feedback paths. One of them is based on the transfer characteristics of the feedback transducer which is introduced to increase the transfer gain of the system, and the other is due to a repulsive pressure force inevitably brought about between the gauging nozzle and its counterface when the feedback transducer is added to the system. The static transfer characteristics are shown as the sum of the transfer characteristic of the above two feedback circuits and that of the basic pneumatic micrometer. Dynamically, the system is characterized as a first order system whose transfer gain and time constant vary as a function of the operating pressure.
Two kinds of applications can be considered for the system; 1) under the condition β<1/Ks*|pm, a high sensitive pneumatic comparator with an appropriate gain and response corresponding to the feedback gain can be constructed, 2) by designing the circuit so that β>1/Ks*|pm is held over an appreciable wide range of the operating pressure, pneumatic switching devices can be obtained, where Ks* is the transfer gain of the pneumatic micrometer circuit without feedback and pm is the operating pressure at which Ks* attains its maximum value.
