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of the leg diameter. On the assumption that the leg is circular in cross section and the swelling
develops uniformly, the magnitude of the swelling defined in this study is roughly estimated by the
calculation that the increase of diameter is multiplied by 3. Figure 3 shows the correlation between the
magnitude of the swelling estimated by the digital camera method and the one measured by SWELL.
There is a strong correlation between them.

5. CONCLUSION

A measuring device (SWELL) for lower leg swelling of the human was developed and the accuracy of
the device was checked. Experiments were carried out to measure the swelling of the lower leg in the
standing work tasks. The results are summarized as follows:

(1) SWELL consists of a flexible wire, a coil spring, and a flat spring with a strain gauge. The strain
that the flat spring produces is measured as the leg swelling develops.
(2) SWELL has the following characteristics: A linear relationship exists between the voltage outputs
of the strain amplifier and the expansion within 10mm of the coil spring. The strain gauge has no
drift in the course of time. As the temperature of the object to be measured rises, the output of
SWELL does not increase but decreases slightly. The amount of decreasing is sufficiently small
around the temperature of the lower leg.
(3) SWELL can continuously measure the leg swelling defined as the increase of the circumference
length of the leg. The magnitudes of the swelling increase linearly, and the measured average
magnitudes are 3.0mm after standing for 30 minutes.

6. REFERENCES

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