Biomedical Engineering Reference
In-Depth Information
Figure 1.9
Shadow Dextrous Hand holding a light bulb [78] (© Shadow Robot Company 2008)
Sensing plays an important and prime role in robotic paradigms, the other two being
planning and control. Proprioceptive sensors sense the position, orientation and speed of
the humanoid's body and joints, and accelerometers measure velocity using integration;
tilt sensors measure inclination, force sensors affixed in the robot's hands and feet mea-
sure what contact forces have taken place with the environment; position sensors show the
actual position of the robot (from which the velocity can be calculated by derivation or
even speed sensors). Arrays of tactile sensors can be used to provide data on what has been
touched. Tactile sensors will provide information about those forces and torques that have
been transferred between the robot and other objects. As shown in Figure 1.9, Shadow
Dextrous Hand [78] reproduces all the movements of the human hand and provides com-
parable force output and sensitivity that makes it possible to manipulate delicate objects
such as fruit and eggs. For this same reason, and because it is much weaker than a person, it
is safe to use in the presence of human beings and is currently being used for telepresence
applications, rehabilitation, and assistive technology, as well as for ergonomic research.
The human body does, however, have much greater flexibility and freedom of
movement than can currently be transferred into a humanoid form and so can perform
a much greater range of tasks. Although these characteristics would be desirable in
humanoid robots, the logistics and complexities required are not presently considered
either feasible or viable.
