I’m reading through Oomlout’s Arduino Experimenter’s Guide. Here are a few interesting tidbits from Wikipedia in the domain of mechanical and materialengineering:
Servomechanism: An electromechanical system regulated by error-sensing feedback. Used for position-control in robotic design. In a servomotor, a variable resistor may sense current position. A microcontroller triggers a positional movement using pulse width modulation. When the variable resistor reaches the correct resistence, the servo shuts off.
Elastic modulus: a measure representing elastic deformation of, say, a piezoelectric sensor. It’s measured as the slope of the “stress-strain curve in the region of deformation”. Bonus: volumetric and tensile elasticity; modulus of rigidity.
Bone electricity: Does bone deliver (piezo)electric feedback? Researchers hypothesize a native electrical effect of bone deformation in bone remodelling. The linked article states that an experimental model does not yet exist to test bone electrical feedback in vivo. Nonetheless, researchers have measured dry bone, and the inferred bone shape maps closely to the measured bone topology. To see for yourself, track the dotted outline on the image here. Credit goes to Andrew Marino of LSU’s Department of Orthopaedic Surgery.