Biomedical Engineering Reference
In-Depth Information
technology has also been tested in humans (Swain 2008) and got positive results.
It is a promising solution for the propulsion of wireless capsule endoscopes if the
design of the device is further optimized, and the safety and controllability of the
mechanism are stringently assessed.
13.3.2 Mechatronic locomotion mechanisms
Engineers are seeking bio-inspired mechatronic solutions for the locomotion of the
wireless capsule endoscope. The research team of CRIM Lab developed a series
of active locomotion mechanisms based on bio-inspired legs (Menciassi
et al.
2004;
Quirini
et al.
2008; Valdastri
et al.
2009). The legs were made of superelastic shape
memory alloy (SMA) ending with 200 micron high hooks to provide friction. In
the initial version each leg was driven by a SMA actuator independently, and later
brushless micro DC motors were used to actuate several sets of legs. The number
of legs in the prototypes varied from four to twelve.
Fig. 13.6
shows the outward
appearance of a 12-legged robotic capsule. A human machine interface (HMI) was
responsible for control of the movement. In-vitro and in-vivo tests proved that the
mechanism could proceed and stop in the small intestine.
Glass
et al.
(2008) also studied on the legged feature for the actuation of capsule
endoscope. Yet they put particular emphasis on enhancing the friction between the
leg and the wall of the intestine. Micro-patterned adhesives inspired by gecko and
beetle foot hairs were applied to the robotic legs so as to anchor the device at a
fixed location. It was supposed to reduce the actuation force significantly by using
micro-pillars coated with a thin silicone oil layer.
Kim
et al.
(2005) developed a capsule prototype with two-way linear actuators
using four pairs of SMA springs. Biomimetic micro-hooks acted as clamping
Figure 13.6
The outward appearance of a 12-legged endoscopic capsular robot. (Repro-
duced from Valdastri
et al.
(2009)).
