The document discusses the limitations of battery power for small autonomous robots and soldiers. While smaller robots are safer and more practical for defense applications, current battery technology only allows for an hour or two of operation, which is not enough. Batteries are also limited in their energy density and unlikely to improve much in the next 10-20 years. The document proposes potential alternative power solutions that could be explored, such as photovoltaic energy capture from flames, novel engine/generator combinations, or single-use power sources that last a day or two before recycling. It concludes that long-endurance power sources for smaller robots present an opportunity for defense applications if technical challenges can be addressed.
Introducing the problem – Robotic and Autonomous Systems (everyone but MOD uses that term, it means the same as Autonomy) seem tantalising close but for MOD robots are very expensive and so little used
Component prices have tumbled - batteries, motors, servos, sensors, telecoms,navigation, single chip computers
Complex autonomy increasingly mastered
Driverless cars
This is why we are especially interested in small robots. We can embed small robots in human teams and use them in an ad-hoc way in close proximity to people, with little hazard. Big machines are dangerous to be near, you have to separate people from heavy machinery.
In the case of RAS there is the extra problem that complex software is very hard to verify ie ‘prove’ it will always act in a safe and predictable way.
Unfortunately we need small-ish but long endurance robots. They have to ‘keep up’ with people who can operate for days without resupply. Recently the Samsung Galaxy phone has become infamous for bursting into flames, but actually this is a well established problem. The Boeing Dreamliner had similar battery problems and MOD is well accustomed to high energy batteries posing hazard.
Unfortunately we need small-ish but long endurance robots. They have to ‘keep up’ with people who can operate for days without resupply. Recently the Samsung Galaxy phone has become infamous for bursting into flames, but actually this is a well established problem. The Boeing Dreamliner had similar battery problems and MOD is well accustomed to high energy batteries posing hazard.
And the battery problem is persistent. If you look at future chemistries being mooted, they are all limited by the energy density of their ingredients which is very inferior to hydrocarbon energy storage. For bigger machines, we solved this problem years ago. We just use heat engines and electric generators, more recently big fuel cells are becoming competitive. But these solutions are not, for whatever reason, available in ‘shrunk’ form
So, can we solve the energy storage problem by using a fuel that mixes with something in the environment to produce power? In this case, electrical power? We know that better batteries start to look a bit like bombs and cannot ‘win’ this race anyway. So what can, in the ‘small and lightweight’ space? Nature has solved it using hydrocarbons. We have solved it, for big engines, using hydrocarbons. And we know they can be managed fairly safely.
Hydrocarbon power?
Favoured for bigger engines, and by living creatures
Stores high energy per unit weight
Do not have to carry oxidant (uses air)
Relatively safe compared with pre-mixed chemicals
Batteries
And bombs?
Any other lightweight energy ideas?
But we want to pose the problem – lightweight compact power- and ask you how to solve it. We are pretty sure it can be solved, these are the kind of things we read about in research papers and from hobby experimenters. On the last idea (Wankel generator), its an area we have funded in the past a
and while the result was a bit big it was well on the way.
Microturbines including Tesla (1911 patent)
Miniature conventional engines
Stirling engine based generators
Hydrogen storage plus generators
Miniature Wankel engine generator?
But we want to pose the problem – lightweight compact power- and ask you how to solve it. We are pretty sure it can be solved, these are the kind of things we read about in research papers and from hobby experimenters. On the last idea (Wankel generator), its an area we have funded in the past and while the result was a bit big it was well on the way.
Detectability -Naturally we want this to be silent, invisible and cost effective - but we also want it to exist!
Work around - For example a generator/battery hybrid could run silent on batteries then recharge using the generator
And here are two final pieces of the jigsaw. Digital Manufacturing is coming of age, not least with low cost 3D printers. Basically we can now make small and complex mechanical structures, in small volumes, cheaply. So long as you do not want them to last forever!
But we do not want them to last forever. If we have to change and recycle the power source in these little robots, that is fine. With the jobs we have in mind they are going to get lost and broken anyway, we are no more worried about replacing a power plant than a battery.
So long as it is low environmental hazard / recycleable. Yes, we do know you can make small atomic batteries.
And here are two final pieces of the jigsaw. Digital Manufacturing is coming of age, not least with low cost 3D printers. Basically we can now make small and complex mechanical structures, in small volumes, cheaply. So long as you do not want them to last forever!
But we do not want them to last forever. If we have to change and recycle the power source in these little robots, that is fine. With the jobs we have in mind they are going to get lost and broken anyway, we are no more worried about replacing a power plant than a battery.
So long as it is low environmental hazard / recycleable. Yes, we do know you can make small atomic batteries.