until zero output voltage drift was seen. Under such a

tion, tbe bias current would equal the external current supplied. We then replaced the 100-pF capacitance with a 100- nF capacitancc, in order to increase the saturation time 10IXi- fold. This circuit thus minimized the drift due to bias current.

that thevariaaons. This would be true only if input were almost zero. However, the algorithm

would not work when force variations are present during this

time of 40 gs. which is the normal case.

APPLICATION

Sensation in the feet may be lost bed:ause of diabetic polyneuropathy [5]. Dial:etics tend to abuse their feet while

to the ampuation of the foot.

A portable data-acquisition system has been developed to imasure the pressure patterns under seven different l‹x:ations in the fooc The jx›rtable system consists of seven sensors imbedded in the insoles of each P.W. Minor Super X extra- depth share, a portable device that includes the amplification and data-collecéon electronics, and flat cables running from the shoes to the device that is mounted at the waist. The system can continuously collect pressure data for 7 min at a

35-Hz saixipling frequency from each of the 14 channcls. The stored dam are dumped thin the micropixx:essor to the IBM PC for data analysis and display (73.

DIS CUS SION

The piezoelcctric sensor is tkin, rugged and low cost. It operates with simple, and power-efficient elecaonics. The sensor has good linearity. Since the sensor is insulated with Mylar film, it is free from moisture and dust. However, the fact that it does not resJxind to steady pressures must be

ACKNOWLEDGMENT

This investigation was supported by Contract Number V695-P29O6 from the Rehabilitation Medicine Service, Veterans Administration Medical Center, Milwaukce,  WI.

REFERENCES

[1]. M. Hennig, P.R. Kavanagh, H.T. Albert, and N.H. Macmillan, “A piezoelectric method of measuring the vertical conflict stress beneath the human food” J. Biomed. Eng.. jo(   4,  pp.  213—222,  1982.

[2]. S.G. Karr, T. Karwoski, J.E. Jacobs, and L.F. Mockros, "Transducer system for the noninvasive recording of arterial pressure contours," Ann. Binned. Eng., jot.   13,  pp.  425--442,   1985.

F. Basta, B. Carbons, P. Dario, D. Oe   Rossi,

Perfetti, "A computerized platform for the

analysis of spatio-temporal foot-ground pressure patterns,"

 Biol. Eng., Espoo, Finland,  pp.

420-421, 1985.

[4]. P. Dazio, and G. Buttazzo, "An anthropomorphic robot finger for investigating artificial tactile perception," Robo(icz  Yes., Vol. 6, no. 3, pp. 25--48, 1987.

摘要：我们已经设计和建造的压电传感器，从市售的Kynar压电膜（PENNWALT公司），它可以用于各种压力测量应用。 传感器为42 x 19 x 2 mm，压电膜厚度仅为52 pm。 我们测试了传感器，发现线性很好。 我们计划使用这些传感器在脚的骨骼突出处进行压力测量。 我们讨论这些测量中涉及的电路和问题，并提出解决这些问题的方法。论文网

介绍

几位研究人员使用了压电传感器。 Hennig等人 [1]开发了鞋垫（用于测量脚部接触应力），由499个锆钛酸铅传感器阵列组成，每个传感器为4.78 x 4.78 x 1.2 mm。然后将它们嵌入3 4 mm高弹性硅胶层 橡胶。 所有传感器都布置在薄的铜布片上。 薄铜线连接到上电极，并运行到包含电子单元的小背包。

卡尔等人[2]开发了用于测量动脉压波形的传感器系统。 Starita等人[3]开发了一个由128个10mm直径的圆形传感器组成的感测位置矩阵，用于测量裸脚和地板之间的压力。