EcoBot

Abstract: Artificial muscles based on the dielectric elastomer actuator (DEA) are an attractive technology for autonomous robotic systems. We are currently exploring their use on EcoBot (Ecological roBot), an autonomous robot being developed by Bristol Robotics Lab that uses microbial fuel cells (MFCs). DEA will provide actuators for fuel cell maintenance and other goals and will increase active mission time through greater mechanical efficiency and reduced mass. Artificial muscles use high voltages and running them normally requires voltage converters to boost the voltage on delivered charge several hundred times. A dielectric elastomer generator (DEG) when used with a recently developed self-priming circuit (SPC) can supply the high-voltage power directly to artificial muscle systems. The SPC can also be started using an initial low-voltage charge from another energy harvester such as a bank of MFCs or a solar cell array. This combination could lead to a completely autonomous power source for robotic artificial muscles. We demonstrate a proof-of-concept portable self-primed DEG for harvesting wind energy from moving tree branches.

Abstract: This paper reports on the proof-of-concept work to produce an energetically autonomous robot employing an artificial metabolic system using Microbial Fuel Cells. The present study compared the effects of changing a number of critical parameters, which control the fuel cell system, as a means to improve its overall performance. We demonstrate that the development of a fuel cell as an artificial metabolic system is feasible and it can provide sufficient power for a mobile robot platform to execute photo tactic ‘pulsed’ behaviour. The robot is code-named EcoBot I and it is the first robot in the world to be directly and entirely powered from bacterial reducing power.

Abstract: This paper describes the work carried out to develop EcoBot- III, which is a robot with an artificial digestion system. The robot is powered by Microbial Fuel Cells (MFCs) and it is designed to collect food and water from the environment, digest the collected food and at the end of the digestion cycle, egest the waste. EcoBot-III operated successfully for 7 days when fed with anaerobic or pasteurized sludge, before mechanical failure required human intervention. Work is ongoing to improve the mechanics and thus extend the artificial agent’s operational lifetime.

Abstract: We consider the embodiment of a microbial fuel cell using artificial muscle actuators. The microbial fuel cell digests organic matter and generates electricity. This energy is stored in a capacitor bank until it is discharged to power one of two complimentary artificial muscle technologies: the dielectric elastomer actuator and the ionic-polymer metal composite. We study the ability of the fuel cell to generate useful actuation and consider appropriate configurations to maximally exploit both of these artificial muscle technologies. A prototype artificial sphincter is implemented using a dielectric elastomer actuator. Stirrer and cilia mechanisms motivate experimentation using ionic polymer metal composite actuators. The ability of the fuel cell to drive both of these technologies opens up new possibilities for truly biomimetic soft artificial robotic organisms.