Abstract—This paper proposes the use of Electric Field
Sensors to implement “pretouch” for robotic grasping. Weakly
electric fish use this perceptual channel, but it has not received
much attention in robotics. This paper describes a series of
manipulators each of which incorporates Electric Field Sensors
in a different fashion. In each case, the paper presents
techniques for using the sensors, and experimental data
collected. First, a simple dynamic-object avoidance technique
is presented. Next, a 1-D alignment task for grasping is
described. Then linear and rotary electrode scanning
techniques are presented. It is shown that these techniques can
distinguish a small object at close range from a large object
farther away, a capability that may be important for grasping.
I. INTRODUCTION
ision is a long range sense with high spatial resolution.
Tactile sensing can also provide high resolution spatial
information, but at a range of zero. This paper explores the
use of Electric Fields to provide a sense of “pretouch,” with
range intermediate between vision and contact-based touch
sensing. Using pretouch, a robotic grasper could align itself
with a target object, and pre-shape appropriately to prepare
for a successful grasp. The difficulty with relying on
contact-based tactile sensing for these purposes is that
touching the object may change its pose.
Weakly electric fish such as Eigenmannia virescens are
able to sense their natural environment by generating
electric fields and measuring perturbations in the field
caused by nearby objects.[1] This perceptual channel has
received little attention in robotics, perhaps in part because
humans are unable to sense electric fields. Although
animals are not known to use this sense for grasping, it
appears
to be well-suited
to guiding grasping
in
incompletely known environments.
This paper describes initial experiments with electric field
sensors integrated into a manipulator. The sophistication of
the mechanical sy