Biomedical Engineering Reference
In-Depth Information
IPMNC
Power supply
IPMNC
FIGURE 9.1
The IPMNC gripper concept (top) and a four-finger gripper (bottom).
and thus close or open the gripper fingers as desired. The hooks at the end of the
fingers represent the concept of nails and secure the gripped object that is encircled
by the fingers.
To date, multifinger grippers that consist of two, four, and eight fingers have
been produced, where the four-finger gripper shown in figure 9.1 was able to lift
10.3-g mass. This gripper prototype was mounted on a 5-mm diameter graph-
ite/epoxy composite rod to emulate a lightweight robotic arm. This gripper was
driven by a 5-V square wave signal at a frequency of 0.1 Hz to allow sufficient time
to perform a desirable demonstration of the capability of the gripper (opening the
gripper fingers, bringing the gripper near the collected object, closing the fingers,
and lifting an object with the arm). The demonstration of this gripper capability to
lift a rock was intended to pave the way for a future potential application of the
gripper to planetary sample collection tasks using ultradexterous and versatile end-
effectors or to handle soft biological objectives. Interestingly, the work at NASA/JPL
(Shahinpoor et al., 1998) reported that the actuation properties of IPMNCs' muscles
in a harsh space environment, such as 1 torr of pressure and -140
°
C temperature,
are noticeable for space applications.
9.2.2
T
-D
A
HREE
IMENSIONAL
CTUATOR
Figure 9.2 shows an illustrative view of a three-dimensional IPMNC actuator
C
packaged in three-dimensional form for use with a three-phase generator box
M
.
is a hollow triangular tube configuration consisting of three
independent membrane actuators,
IPMNC actuator
C
A
, attached and electrically insulated along the
