**3.4. Other SMA-based actuation systems**

12 Will-be-set-by-IN-TECH

In [38] a robot inspired by the inchworm Ascotis Selenaria is presented. The robot, called Omegabot, is named after the omega (Ω) shape of the crawling motion of the inchworm. Figure 8 shows the Omegabot platform. Previous work about this robot can be also found in

Experimental results report the first step for establishing an inchworm-like robot that can crawl on various terrains where conventional robots cannot move. The Omegabot uses a SMA coil actuator that requires a current of 200*mA* for activation. The frequency of motion is about 1*Hz*, limited by the response time of the SMA wires. The inchworm robot is manually controlled by an IR remote operation, and it achieves a maximum linear velocity of 5*mm*/*s*.

**Figure 8.** Omegabot, a biomimetic inchworm robot, grasps the branch of a wood, raises its head, and

In [34] a bio-mimetic micro earthworm-like robot with wireless control is proposed. The actuation mechanism consists on a SMA spring that contract and extend the earthworm muscle respectively. The proposed mechanism is simple but effective when traveling in narrow and rough environments, such as human digestive organs, bended long pipeline and so on. Also, this micro robot incorporates both control and power supply onboard. The theoretical speed of the micro robot is approximately 3.4*mm*/*cycle*, where the total time per cycle is 8*s* (the contraction time of the SMA is 2*s*, whereas the recovery time is 6*s*). The fabricated micro robot can move with the velocity of 10*mm*/*min* during 8 minutes. The stroke

A concept similar to the one depicted in Figure 9 has been proposed in [48]. A SMA-spring has been used for changing the axial length of worm's modules, and consequently changing

*3.3.2. Omegabot: Crawling robot inspired by Ascotis Selenaria*

The robot travels a distance of 5*mm* per stroke.

turns right. Bottom right: Proleg of Omegabot [38].

per cycle is 2.0*mm*.

*3.3.4. Other peristaltic motion concepts*

*3.3.3. An earthworm-like micro robot using shape memory alloy actuator*

[37].

In this section we present two works that do not address the development a full robot, but rather studying and developing appendices to be added to future full robotic systems.
