Page 62 - Handbook of Biomechatronics

56 Reva E. Johnson and Jonathon W. Sensinger

4.2 Biological Function Augmentation
Another purpose of biomechatronic systems is to augment the human body
in some way. The goal may be to regain function diminished by motor dis-
orders (e.g., stroke or traumatic brain injury), or to amplify typical human
function for people in demanding environments.
Orthoses (also called exoskeletons) may be used as either stationary or
wearable devices. Stationary devices such as the Lokomat focus on rehabil-
itation. They are typically very large and stable, with traditional electric
motors as actuators. Wearable orthoses are used for a variety of applications
ranging from assistance for people with motor disorders, to support for sol-
diers traveling long distances with heavy loads. The actuators vary widely,
especially in research systems. Many use compliant or variable-impedance
actuators. For a review of actuators for orthoses, see Veale and Xie (2016).
There are many other applications of biological-function augmentation.
For example, surgical tools and medical devices augment the capabilities of
physicians, and haptic interfaces enable people to interact with virtual, small-
scale, remote, or dangerous environments.

5 CONCLUSION

The capabilities of biomechatronic actuators have been increasing rap-
idly due to a number of factors. Traditional actuator technologies such as
electric motors have been decreasing in size and weight (their power sup-
plies, typically batteries, have also been shrinking). Newer actuator technol-
ogies such as SMAs and dielectric elastomers are moving out of research labs
and into commercial applications. These improvements enable closer inte-
gration with humans across a broad range of applications. However, com-
municating intentions from the human to the machine remains a significant
challenge in many systems.
This chapter introduced the design goals, categories, and applications of
biomechatronic actuators. The applications of biomechatronic actuators
range widely, from microfluidic implantable devices to industrial robots that
interact with people. Because of the wide range of applications, we did not
provide specific quantitative guidelines for designing biomechatronic actu-
ators but recommended several important factors to consider. For further
information, we suggest reading the several excellent reviews on more spe-
cific types of biomechatronic actuators, referenced below.