Ecobot III Project

EcoBot-III is shown inside an enclosed thermostatic arena (EcoWorld) and moves along a stainless steel track, between liquid food (wastewater - right-hand side wall) and water (tap water - left-hand side wall). The robot is powered by a stack of 48 Microbial Fuel Cells (terracotta coloured units half-way up the chassis), which receive fresh digested nutrients from the artificial stomach (conical structure underneath the yellow hat). Overflowing fluids from the MFCs are collected in a trough (bottom part of the chassis) and fed back into the artificial stomach for further utilisation. At the end of a complete cycle (approximately after 24 hours) a peristaltic pump evacuates the waste that has accumulated in the bottom of the conical artificial stomach.

• The movie begins with the robot pumping fluid onboard from the artificial stomach down into the MFCs (the visible from the front pipes get filled-up with dark-coloured fluid).
• Then the robot is moves towards the left side-wall where it makes contact with the arena water distribution mechanism and receives water into its collection tray (just below the MFCs). Once again, a demonstration of the onboard feeding takes place (dark fluid fills up the pipes).
• Following this, the robot makes its way towards the right-hand side wall, where it makes contact with the liquid-food distribution mechanism and dark wastewater is pumped into the yellow hat.
• After receiving its liquid food, the robot moves away from the feeding station and goes all the way towards the water distribution mechanism. Half-way between the middle and the left-hand side wall of the arena a liquid 'puddle' can be noticed on the floor inside the black tray, as a result of the daylight reflection. This is the semi-solid/liquid waste excreted by the robot as part of its sequence of actuations.
• The robot then reaches the water distribution mechanism, where it receives fresh water, and once again the onboard feeding is demonstrated before the movie ends.

This same experiment has been carried out with pasteurised (synthetic) wastewater, (i.e. deprived of any microbes) as well as with decomposed-in-sludge fly-juice, with equal success.The efficiency of the MFC stack onboard EcoBot (depending on the substrate) was calculated to be approximately 1% not taking into account the recycling process. As can be seen the time between actuations varies between 40-60 minutes, and the robot has operated continuously in this mode for 7 days. The reason it stopped working after the 7th day, was due to mechanical failures of pumps.

The EcoBot team that has developed this robot consists of Dr. Ioannis Ieropoulos, Prof. John Greenman, Prof. Chris Melhuish, and the technical support was provided by Mr. Ian Horsfield and Mr. Sam Coupland.

The scientific paper reporting on this work will appear in the proceedings of the Alife-XII conference, to take place between the 19-23 of August 2010.

Energy Autonomy The early stage work for the EcoBot-III project, was funded by EPSRC (Grant no. EP-D027403-1), which finished in 2007 and provided the foundation for the BREADbot development (EU FP-6 IST-027819). The main objective of this project was to develop a robot with onboard fluid circulation, capable of collecting its energy from the environment and getting rid of its own waste; all of these functions are powered by the MFCs. Due to the challenging nature of this project rapid prototype technology was fully utilised in order to produce a uniquely designed, lightweight and strong robot structure comprising multiple parts. Furthermore, because of the scarcity of onboard energy, the team was required to develop ultra low power electronic circuitry to operate the robot. The image at right shows the current ecobot team. Ingestion/Digestion/Egestion Vessel This is the upper most component of the robot which constists of the ingestion, artificial digestion and solid waste excretion mechanism. The image clearly shows sludge within the vessel and solid waste sedimented into the egester. Sludge and Water Distribution and MFCs This is the middle section of the robot which consists of the sludge distribution mechanism (white solid helical rings), and the MFCs (24 in total) which are shown just below the distribution mechanism. Underneath the MFCs there is an overflow collection tray which feeds back into the ingestion vessel above.
Video Gallery Note that the DivX software/codec is needed to play these files.
This movie is a sub-assembly test for the solid waste removal system, this is not powered by MFCs.	This movie is a sub-assembly test of the sludge distribution system, this is not powered by MFCs.
Links Ecobot Project & Team Ecobot I Ecobot II Artificial Gill Ecobot Home
For more information or any comments about the ecobot project please contact Dr. Ioannis Ieropoulos email:ioannis.ieropoulos@brl.ac.uk