Page 70 - Handbook of Biomechatronics

Sensors and Transducers 65

The first thing you do with Jacob is to measure many of his body’s dimensions,
specifically the difference between the sound side of his body and side with the
amputation. A ruler is a convenient tool for such a task.

2.2 Protractor

Aprotractor (Fig. 4) is used to measure angles (https://en.oxforddictionaries.
com/definition/protractor, Accessed 21 August 2017). By aligning the center
point and the 0 axis of the protractor with the center of rotation and the
reference plane, an angle can be measured through visual inspection of the
angle indicators.
You measure the angle of alignment between Jacob’s prosthetic foot and
his prosthetic knee using a protractor. You align the central axis of the foot/
ankle system with the axis of the protractor and hold the edge of the pro-
tractor horizontal to the ground. Then, you read the angle off the protractor.

2.3 Goniometer

Agoniometer(Fig. 5) is a device used to measure angles, similar to a protrac-
tor, but more specifically designed for measuring body joint angles (https://
en.oxforddictionaries.com/definition/goniometer,Accessed21August2017).

Fig. 4 Example of a protractor.

Fig. 5 Example of a goniometer.