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Darpa Shows Off Some Things You Can Do with Distributed Electric Propulsion
- TaylorAlexander 8y agoIf any of y’all like this, I am building an open source 3D printed off road robot with in wheel motors and transmissions, and I post regular updates on the project on YouTube. The transmission is currently an 11:1 two stage planetary gearbox that is almost entirely 3D printed (aside from some bearings, screws, and metal pins). I recently drove 2.2 kilometers with it but I’m shooting for 20km and hopefully 50+kms between gearbox services. Can be made on a $1k printer and it’s all CC0 open source. Code is python on Raspberry Pi. Please check it out if that sounds cool! https://youtu.be/cU_0M1_TvD0 https://youtu.be/cU_0M1_TvD0
- arketyp 8y agoI liked that part of the DARPA-demo the best for sure. It seems obvious that vehicle suspension should be dynamically controlled by software anticipating the terrain. (Maybe cars already have this technology to some extent? I'm not sure.) What's the soft tech in your robot?
- TheSpiceIsLife 8y agoThere’s been at least two attempts at active suspension I’m aware of. One is quite old. It came up in discussion on HN recently. Back shortly with a link. Update: link as promised https://news.ycombinator.com/item?id=17108828 https://news.ycombinator.com/item?id=17108828
- rasz 8y agothere are electric sway bars https://www.youtube.com/watch?v=zVNHkGq9fDc https://www.youtube.com/watch?v=zVNHkGq9fDc bose electromagnetic suspension: https://www.youtube.com/watch?v=WOR8eKBLwXQ https://www.youtube.com/watch?v=WOR8eKBLwXQ student project: https://www.youtube.com/watch?v=IQ1eKddstxM https://www.youtube.com/watch?v=IQ1eKddstxM
- Already__Taken 8y ago> Maybe cars already have this technology to some extent? It was banned in F1, that combined with the skirts for downforce meant for insane low ground clearances with grip off the scales. You could see cornering speeds going up seemingly without end. context: https://www.racefans.net/2007/05/17/banned-active-suspension/ https://www.racefans.net/2007/05/17/banned-active-suspension...
- intruder 8y agoEven non-computer aided active suspension was banned. Good readup: https://www.autosport.com/f1/news/127638/f1-latest-suspension-row-explained https://www.autosport.com/f1/news/127638/f1-latest-suspensio...
- gameswithgo 8y agosome F1 cars had it briefly in the 1970s and it was outlawed. Cars would lean into the turns, nose up when braking, nose down when acclerating. crazy stuff.
- TaylorAlexander 8y agoHello! I’m not sure I understand the phrase “soft tech”, but Rover uses some large springs for suspension and has big foam tires. I could build active suspension but it dramatically increases the cost and complexity of the robot, which goes counter to my goals. Some low cost active suspension would be helpful though! Right now I’m just focused on keeping the thing reliable. :)
- cornholio 8y agoI myself have some interest in the software side of this. I see the robot is remote controlled - but I think a large degree of autonomy would be required for a 50Km trip. The current self driving technology relies on a trunk full of Nvidia cards sucking data in from a few dozen cameras, lidars or radars all working to create a coherent world view, the whole system drawing hundreds of watts of power. I wonder if it's possible to capture 90% of the performance of that system with simple hardware that can fit such minimal hardware and other applications where failure is an option and has limited consequences. A thing I'm thinking about lately are lightweight, electric self driving bikes (or more exactly, trikes) running on existing, dedicated bike infrastructure, augmented with some embedded instrumentation. As long as the speed does not exceed 15Km/h and they are guaranteed to never run a red light or run over any object crossing the path, they could be as safe as a human driven bikes.
- TaylorAlexander 8y agoYes autonomy is super important for a robot like this! I build rover as a platform for autonomy research, as smaller robots I’ve built in the past didn’t have enough room for a high powered compute and an array of sensors. I’m particularly interested in camera only navigation, localization, and obstacle avoidance, and I hope to get an NVIDIA Xavier board and multiple cameras to use as the sensing system. I’m trying to get myself in a position where I finally have to learn machine learning, and Rover is the project for that!
- tomp 8y agoWhy would you want a self-driving bicycle? It’s not like you can relax and read a book during the ride, and it’s not very autonomous either (unless it can stand upright without moving).
- cornholio 8y agoThat's the idea, to relax for the bulk of the trip on dedicated infrastructure, then pedal the last mile to your final destination: https://www.coroflot.com/hadley/enclosed-bike https://www.coroflot.com/hadley/enclosed-bike With solar panels and the right weather, it barley needs to recharge.
- specialist 8y agoNicely done. If the wheels were bigger, it could be double-sided / flippable (no "this side up").
- oh_sigh 8y agoNice project! What kind of 3d printer are you using?
- TaylorAlexander 8y agoThanks! I use a modified Monoprice Maker Select V2 and a modified TEVO Black Widow (which I don’t recommend due to assembly effort). The CR-10 and especially the 400mm version is what I recommend for building Rover!
- cheeko1234 8y agoWow. Another awesome open source project that I will hopefully be replicating. What's the remote control that you're using? I see flutter support in your code and am unfamiliar with flutter. EDIT: Nvm. https://codeduino.com/news/hardware/flutter-the-wireless-arduino/ https://codeduino.com/news/hardware/flutter-the-wireless-ard... http://flutterwireless.com/index.php?route=product/manufacturer/info&manufacturer_id=8 http://flutterwireless.com/index.php?route=product/manufactu... All products out of stock.
- TaylorAlexander 8y agoThank you! Yeah, I’m using Flutter. I’m the person who made Flutter so I have a lot of them. I used to have bluetooth control from iPhone but I wanted a physical interface. Any remote is trivially easy to add though - the remote is a standalone python program that sends GRPC commands to the motors. I recently got a PS4 remote and may add support for that!
- baybal2 8y agoOne advantage of electric transmission for military vehicle is that you don't have a single driveshaft to fail on you rendering you immobile, nor clutches, nor a chance that a single broken wheel will jam the rest of powertrain. The last point is the biggest advantage of many wheels vehicles over tracks. A detracked tank is a sitting duck, but an 8x8 without a single wheel will happily run away after taking damage
- cm2187 8y agoHow easy is it to insulate the electric motors? My thinking is electric motors in the wheels while crossing a river, opportunity for short circuits.
- jasonjs 8y agoThese are probably brush-less motors, so in theory, they shouldn't pose any specific challenges in that scenario, as there are no exposed conductors, only sets of insulated coils/windings and permanent magnets that would end up being immersed in a river.
- justinclift 8y agoEMP sensitive?
- Nokinside 8y agoNot the motors. They are designed to withstand high currents.
- baybal2 8y ago>How easy is it to insulate the electric motors? Very easy. There are submerged electric motors for marine propulsion after all.
- cm2187 8y agoTrue. But they don't take hits and vibrations like a military 4x4 would.
- arketyp 8y agoTechnology is naturally more augmentation than automation. This is closer to the future of driving than the self-driving AI solutions. Our senses will be aided and some tasks out-sourced. This is already happening, has always been happening, e.g. anti-lock braking system or proximity detection with auditory feedback.
- pineaux 8y agoHow are self-driving vehicles NOT an augmentation? We are not talking about self-living bodies here. Self driving vehicles augment our ability to transport ourselves and our stuff without the use of a part of our mental system. It's like walking on the automatic pilot, like in your home, except faster.
- arketyp 8y agoYeah, it is certainly not a clear cut distinction. You know, I initially listed automatic transmission as an example of augmentation. So it goes both ways too. Anyway, they highlight different aspects and I find the notion elucifying.
- stealthcat 8y agoSince this is version 1.0, expect lots of failure in the field then lots of fixes for 2.0
- RugnirViking 8y agoHeck this isn't even version 1.0 - more like version 0.1 It's the first functioning prototype of what will later become version 1.0
- deleted 8y ago[deleted]
- antpls 8y agoWhat is so special? It looks like an advertisement for DARPA and military. Other firms around the world do that too : https://www.swincar.net/ https://www.swincar.net/ (oh! And not to kill people)
- karambahh 8y agoThe video states a 100kw motor per wheel. Wikipedia states the humvee has a 142kw motor. Not only the vehicle would probably be lighter (batteries vs motor, gearboxes, etc) but it would have 2.81 more power, so it would probably vastly overperform current vehicles?
- goodcanadian 8y agoBatteries are heavy. It is not immediately clear to me that the overall vehicle would be lighter.
- karambahh 8y agoDid not realize how heavy modern batteries still were. Tesla Model 3 batteries weight 480kg for 80.5kWh, density of 167Wh/kg. The DARPA vehicle running for 1h at full power would require a whopping 2400kg of batteries! To give a comparison point, according to Wikipedia, 2400kg is the weight of an Humvee. I guess it'll still take a little while until the DARPA concept becomes an actual vehicle...
- vegardx 8y agoNothing that stops them from putting in a small turbine to generate electricity. If memory serves me right, this is what some modern tanks do, like the Abraham. Add in a somewhat small (compared to battery powered only) battery pack and you can use that to power the vehicle when idling.
- SigmundA 8y agoAbrahams use mechanical transmission from the turbines. Some ships and trains use diesel electric drivetrains or even turbine electric but its not for weight or efficiency but controllability. My understanding hybrid electric drivetrains are around 80% efficiency, while normal mechanical drivetrains are in the mid 90's. This is why nearly all hybrid cars switch over to normal mechnical drive typically at highway speeds as it more much efficient, while in the city in stop and go the electric drive train beats it due to regeneration and stop light idling.
- black_puppydog 8y ago1st thought: wow, cool stuff! 2nd thought: too bad it's gonna be military use first. I've often heard the argument being made that military applications (and even war itself) somehow drive innovation. While that may be true to an extent, it always rang hollow to me as an argument. Why should civil life always just get the "crumbs" of science and engineering? Why not turn it around, spend most of the research money and brain time on things that benefit everyone (in the US, and worldwide) and then see which of those technologies can be repurposed for the military, not the other way around? DARPA alone has a bigger budget than NASA, and I just googled "us military research budget" and the numbers for all the arms of the US military are quite staggering, really.
- cabalamat 8y ago> Why not turn it around, spend most of the research money and brain time on things that benefit everyone (in the US, and worldwide) http://slatestarcodex.com/2014/07/30/meditations-on-moloch/ http://slatestarcodex.com/2014/07/30/meditations-on-moloch/ is why not
- specialist 8y agoThank you. Mostly for the fish farming thought experiment.
- phs318u 8y agoWow! Thank you so much for that link.
- smaddox 8y agoInteresting read so far. The fish farming story is a nice example. For further analysis around the same topic, https://equilibriabook.com https://equilibriabook.com is a great read.
- swebs 8y ago>8. Arms races. Large countries can spend anywhere from 5% to 30% of their budget on defense. In the absence of war – a condition which has mostly held for the past fifty years – all this does is sap money away from infrastructure, health, education, or economic growth. But any country that fails to spend enough money on defense risks being invaded by a neighboring country that did. Therefore, almost all countries try to spend some money on defense. >From a god’s-eye-view, the best solution is world peace and no country having an army at all. From within the system, no country can unilaterally enforce that, so their best option is to keep on throwing their money into missiles that lie in silos unused. Funnily enough, we can come full circle and say that many developed nations can survive these days with very little military spending just because America's massive military is enough of a deterrent. https://en.wikipedia.org/wiki/Pax_Americana https://en.wikipedia.org/wiki/Pax_Americana
- Nokinside 8y agoDarpa should have open betting market for these concepts. Only thing I might moderately bet on is electric motors inside wheels. Electric motors can be more durable, require less maintenance and perform better. That shaping wheel concept is obvious no go. I would bet serious money against it. Tank tread is the weak point even in modern main battle tank. Their design is simpler but they have problems with mechanical complexity and short lifespan and reliability. Tracks getting jammed or thrown track is relatively common. Just take a that wheel to a drive across mud, sand and bushes with lots of sticks and stones and see how it goes. Low maintenance and reliability are high on military priorities.
- Retric 8y agoThe advantage over tracks is you can lock everything and use the wheel anyway over relatively short distances. So, you trade increased complexity for a vastly better failure mode. Yea it's bad for the car and passengers, but being able to move even 1 mile after failure is a huge advantage.
- Nokinside 8y agoYou may not be able to lock it after you drive in dirt for some time or have any kind of failure where you lose the track. Having tires with adjustable air pressure, or just adding extra pair of wheels (you may lift them up) to the vehicle seems like simpler idea.
- Retric 8y agoLosing track on one wheel is not going to stop one of these things from moving in an emergency. Plenty of videos of people driving even normal cars on rims. ex: https://www.youtube.com/watch?v=-1BgwX3hHgo https://www.youtube.com/watch?v=-1BgwX3hHgo
- Nokinside 8y agoYou are focusing on very narrow concept and scenario. The overall maintainability, durability and cost is the issue. The ability of brigades to operate long time independently with minimal maintenance logistics is essential.
- readhn 8y agoi find it hilarious that this is a 118 year old technology! Ferdenand Porsche in 1900 presented a sportscar fitted with four electric wheel-hub motors, it was the first all-wheel drive passenger vehicle. Where is the progress? The cars should have been flying by now.
- wffurr 8y agoPhysical limitations of batteries vs air oxidized fuel. Dragging around your own oxidizer takes a lot of mass which severely limits power. The real breakthrough will be a battery that can use atmospheric oxygen, like a zinc-air battery. But it hasn't worked out in the last 100 years and it's not clear if it ever will.
- readhn 8y agoi agree a significant breakthrough in batteries (or other energy sources) is needed.
- Nasrudith 8y agoBatteries appear to be operating on a vastly slower Moore's law at least. They have been sinfully underfunded as a research field historically.
- MrEldritch 8y agoIt's not really a "Moore's law" thing at all - it's more that, like every single other technology in history that isn't specifically semiconductors, batteries don't follow an exponential improvement curve. They also evolve slower than many other technologies even on a more typical growth trajectory, because battery chemistry has way less room for easy improvement. There's only a few battery chemistries that could even theoretically offer much better density than lithium-ion, and we've been trying to make them work for a long time.
- pineaux 8y agoMy bet is on graphene capacitor batteries.
- DanielBMarkham 8y agoThat extreme suspension vehicle looks like something out of Batman. Bet it's a hoot to drive. I thought it was interesting that while they're doing a ton of research, it's all one-off stuff. In other words, they could have required all of the experiments to ter with one another using some standard framework. Then they could mix-and-match various experiments to see how well they work with one another. Instead, it looks like they're evaluating each one separately -- with some huge integration nightmare up head if any of them ever make it into the field. I wonder why they do it that way.
- solidr53 8y agoIm not sure that RD works that way. Innovate, time and compatibility, pick two.
- DanielBMarkham 8y agoI don't know. I know that some mention was made of the pieces fitting already-existing army wheel specs. So obviously for some groups integration was a consideration. And it's a mistake to think in all-or-nothing thinking here. I didn't say you needed to design a rock-solid integration system, only that it looked like integration was a minimal concern -- and that was an interesting choice. I come from the tech community. The longer we put off integration, the more expensive things become.
- dannypgh 8y agoPutting off integration is cheaper when it's not yet clear what you need to integrate with. Or to frame it differently: having requirements of "be everything for everyone" is a surefire way to fail.
- hedvig 8y agoThis sub-thread reminds me of the monolith vs microservices kernel discussion I see a lot here. Doesn't Linux benefit from specialized pieces being piped together at will?
- dugluak 8y agoThe sad part of building all this technology is they need a WAR to put it to use.
- deleted 8y ago[deleted]
- mrfusion 8y agoI hope cars will do this once we’ve gone electric. Imagine how long you could keep a car if you can swap out a motor with a jack and a socket wrench.
- dsfyu404ed 8y agoThe unsprung mass of hub motors makes them terrible for handling, especially at speed (military vehicles top out at "slow person in the right lane" speeds). When you've got a teardrop shaped turd (or economy car, whatever your preferred pronoun is) that's riding 2in off the ground (because how else are you going to be aerodynamic enough to deliver reasonable range) and nearly nil suspension travel (relative to anything expected to operate off road) drive-train and power transmission packaging isn't really an issue (whereas that was the primary issue solved here by going electric). You should expect to see centrally mounted motors driving the wheels via CV shafts as the dominant EV power-train for the foreseeable future.
- deepnotderp 8y agoDoesn't zoox use independent motors?