在尺寸测量中,广泛地应用着各种不同结构的气动量仪。如果在气动系统中采用负反馈,则可显著地扩大仪器的测量范围。文献[1]中提出的尺寸测量装置,其结构原理如图1所示。整个装置包括:主体7;装在主体内的两个同轴波纹管8和6,其有效面积各不相同,并在它们之间形成一个空腔;一 In the size measurement, widely used in a variety of different structures of the pneumatic gauge. If negative feedback is used in the pneumatic system, the measuring range of the instrument can be significantly enlarged. The literature [1] proposed size measurement device, the structure of the principle shown in Figure 1. The whole device comprises: a main body 7; two coaxial bellows 8 and 6 housed in the main body of different effective area and forming a cavity therebetween;