My personal opinion is that electric (battery powered)·robots are the most efficient. When you add gasoline, diesel or bio fuels you end up with a lot of waste in the form of heat. Take a Honda generator, start it up and plug in your cell phone charger and you’ll see what I mean about efficiency. I ordered one of those hydrogen fuel cell experimenter kits, I don’t believe that it’s the answer either, but it should be a step in the right direction.
Also, all the nessasary computer equipment to run a robot is power by electricity.· So you have to have electric power on board anyway, it makes it simplier to have only electricity than gas and electricity.
Electricity is very nice stuff. We've got pretty good batteries, excellent motors, inexpensive servos, and the BS2.
The power system to run a gasoline or hydraulic powered robot tends to be a bit pricey. You usually need some electrical system in there to run the robot 'brain' anyway. And then, the amount of power with a gasoline powered robot is SO huge, a run-away robot can do serious damage to itself and people around it.
There's also the size issue. Even a small gasoline lawnmower motor weighs several pounds and wouldn't fit in a mini-sumo robot. Oh, and there's a noise issue, and a dirt issue, and that you shouldn't run a gasoline engine indoors without adequate ventilation.
Having said that, I believe some of the larger (3' x 3') battlebots are gasoline powered.
So, the short answer is, batteries and small electric motors and sensors are SO much simpler to use, and apply to many more situations than a gasoline engine would.
Oh, and note also the Parallax BS2 is a pretty limited processor.· It's great for learning, proving out prototypes, and for onesy-twosy projects.· It might be considered "limited" in terms of speed and memory for somebody willing to spend $3,000 or more on a gasoline robot.·
Post Edited (allanlane5) : 3/15/2007 1:43:39 PM GMT
Gas robots have potential to handle diverse terrain and travel long distances. They can get heavy pretty quickly, because you'll either still have motors or hydrostatic/transmission systems. But the power is really nice to have laying around. You have to prototype everything in your garage since the engine emissions are dangerous and dirty.
On the flip side, they're a lot of fun!
Ken Gracey
Parallax, Inc.
Post Edited (Ken Gracey (Parallax)) : 3/15/2007 4:32:25 PM GMT
Are those Goped tires on the 2nd one?, Nice Job on both of them, Very professional looking. ·
I asked, because that’s where my interests are. I own a small engine dyno that even Zenoah (Japan) is envious of. With the Air Force wanting "Heavy Fuel" (Diesel) drone engines, I thought there would be more people doing diesel engines in Bots similar to yours. Maybe someday I’ll build a diesel powered BOE-BOT or Sumu Bot, that would be way·cool. ·
In the past I’ve mentioned my model airplane project, (naturally I like drones too). Here is a picture of our Ashley powered·by a ·ZDZ 160 cc and Zenoah GT-80 powered Kelly F1-C and the Dyno (btw, that's not me in the pic)
Post Edited (Capt. Quirk) : 3/16/2007 1:43:42 AM GMT
Another reason I mentioned it was, with the model airplanes, electric powerplants were gaining in popularity 25 yrs ago. But back then motors were cheap, but by the mid 90's motors started costing more and especially the batteries and speed controls. To the point·where it was cheaper and lighter to run fuel.
I know they are messy and perhaps not as controlable for small bots, but it would just add to the challange and fun. Many larger engines are avaliable cheap and·easily less expensive than any electrical powerplants for the larger battle bots that allenlane5 was talking about. But they can certainly be made to produce long flat torque curves.
Ken, instead of that Honda, Look at the Zenoah G25 Geo engine. less weight, 100 miles to a gal., California smog legal and excellent low·rpm, torque·power band. (Much better than the Honda)
I've seen the Zenoah engines before. Maybe I'll give one of those a try on my next project. The Honda weedwacker engines have a narrow power band around 4-5K RPM, as you indicated.
My SX 28 &·52 projects are Engine Management Systems. Through·the years with our pylon racers we have tried many data loggers and·real time data aquisition systems.·Also since we manufacture very light weight giant scale composite airplanes, we hope our future will be in civil aviation use of drones.
·I have dyno runs of the GEO, I spent a lot of development time with that engine. And more runs on the G23lh, G230rc, G260rc, Fuji BT50 and GT74 & 80 engines.
I just took a second look at those·links again, I new the first one was the 30 or 35 cc 4 stroke. But the second one isn't, how big is it?
Ah good old dinosaur juice. One of the main things that (infernal) combustion could offer a robotic platform is range. I've built several machines using varios gasoline engines from 6.5 H.P to 13.5 HP for combat use. It is possible to have both electric drive and fossil fuel drive systems as well. We did that in Half Gassed. It was a semi hybrid design. It didn't recharge the batteries since we only had to run for 5 minutes during a match.
But it had·three modes of operation using straight electric drive or gasoline drive with electric steering or a combination of both power sources for maximum performance.
·It would be interesting to build a long range Diesel/Electric platform. That's probably a good way to build a Scout bot. You could chug along under diesel·fuel power for·say 50·miles·while charging the batteries and then switch to whisper mode·by using electric power for the last mile or so·to sneek up on whatever you wanted to observe without detection..
Of course· fossil fueled automobiles are also becoming more and more robotic and they may eventually not require a driver for everyday grocery getting and commuting. The last DARPA challange demonstrated that the systems required are possible.··But they still need a lot of refinement.
Big robotic vehicles are comming and many of them will still be slurping up those pesky Dinosaurs until a lot better long range·power source is developed and mass marketed.
Heres a heavy fueled autonomus bot for you to ponder.
That Dyno is a miniature of the dyno that ·http://www.huff-tech.com/· has been manufacturing since the early 90's. Darrel made it custom for me, I don’t know if he will ever build another small·one again, But check out his web site.
The HUFF Dynos are not as sophisticated as a Super Flow, But it is a fully automatic dyno. The Huff dyno has a real time weather station and a temperature controlled dyno room and dual monitors. Set the sweep rate, begin and end test parameters and hit a switch and let it go, Scans / Sec of the dyno's strain gauge and sensors depends on your·DAQ card and your operating system, mine is set for 100 scans / sec with 30 to 40% of those resources are dedicated to just the load cell.··
The Huff dyno is a "Hydraulic Brake" dyno and the best feature of this dyno is it's accuracy in both an up sweep and down sweep. The # are soo close that a Super Flow or a Land & Sea can't match it. The Huff dyno is arguably better than many "Eddy Current" dynamometers too.
The least expensive and least accurate dyno is an "Inertia Dyno", But it's is an easy project with any style·Stamp. The limiting factor with which processor you·choose will be RPM or actually RPS (revs per sec) and the amount of measurements you record per revolution, the simplest set up would be 1 per 360 deg of rotation. You determine the torque by measuring the acceleration of a known mass in radians/sec/sec. This style dyno could be done with a hall sensor or an optical encoder and a balanced piece of aluminum or steel and somewhat simulate what your testing (say a go-kart) by using F = M*A.
The real advantage of these dyno's isn't the measurement of Torque and Horsepower, but Acceleration (f=m*a again) The Torque (and HP) vs. TIME, not RPM is it's strength and used in conjunction with a "Brake" style dyno (for accuracy)·can lead to product that substantially out performs the competition.·
Post Edited (Capt. Quirk) : 3/20/2007 5:55:10 AM GMT
That treadmill motor would work and so will any motor that can be reversed into a generator. Measure the·Watts produced·by the test motor and multiply Kilowatts by 1.341 to get Horsepower. Then use a little algebra and you will get torque. The thing I don't like about using that style motor is losses do to friction and heat. You may be able to reduce the frictional losses by either measuring the friction with an Inch/lbs torque wrench and incorporate those losses within your control program, Or minimize those losses with a brushless motor like a "Stepper-motor" or any other type of brushless motor (Hell a computer fan motor would work) ·
The first picture I uploaded is a 2.5cc (.15 ci) RC Car engine using a RC airplane starter motor, setup as a generator. Has a simple encoder to keep track of rpm and I believe a multi-meter, but if he had used a voltage and an amperage transducers and log it to a EEPROM with a time stamp or packet or use the··http://www.parallax.com/html_pages/downloads/software/software_plxdaq.asp it would be much improved. ·
I think the RC Electric Model airplane guys have a lot of information on this subject, from dyno's like this to good simulation software (it's my opinion the RC modelers are ahead because it's been more popular for a longer period than BOTs) Do a search, Maybe check http://www.rcuniverse.com/ ·
Then there is a fine example of a Inertia Dyno and my all time favorite dyno picture. A liberty engine from an old Curtis Jenny biplane. ·
Post Edited (Capt. Quirk) : 3/21/2007 7:19:56 AM GMT
Capt. Quirk
Posts: 872
Comments
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Thank's Brian
www.truckwiz.com
·"Imagination is more important than knowledge..." ·· Albert Einstein
Post Edited (Brian Beckius) : 3/15/2007 11:23:46 AM GMT
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NerdMaster
For
Life
The power system to run a gasoline or hydraulic powered robot tends to be a bit pricey. You usually need some electrical system in there to run the robot 'brain' anyway. And then, the amount of power with a gasoline powered robot is SO huge, a run-away robot can do serious damage to itself and people around it.
There's also the size issue. Even a small gasoline lawnmower motor weighs several pounds and wouldn't fit in a mini-sumo robot. Oh, and there's a noise issue, and a dirt issue, and that you shouldn't run a gasoline engine indoors without adequate ventilation.
Having said that, I believe some of the larger (3' x 3') battlebots are gasoline powered.
So, the short answer is, batteries and small electric motors and sensors are SO much simpler to use, and apply to many more situations than a gasoline engine would.
Oh, and note also the Parallax BS2 is a pretty limited processor.· It's great for learning, proving out prototypes, and for onesy-twosy projects.· It might be considered "limited" in terms of speed and memory for somebody willing to spend $3,000 or more on a gasoline robot.·
Post Edited (allanlane5) : 3/15/2007 1:43:39 PM GMT
Here is one hybrid I made: http://forums.parallax.com/showthread.php?p=612409
Here is one under development: http://forums.parallax.com/showthread.php?p=632652
Gas robots have potential to handle diverse terrain and travel long distances. They can get heavy pretty quickly, because you'll either still have motors or hydrostatic/transmission systems. But the power is really nice to have laying around. You have to prototype everything in your garage since the engine emissions are dangerous and dirty.
On the flip side, they're a lot of fun!
Ken Gracey
Parallax, Inc.
Post Edited (Ken Gracey (Parallax)) : 3/15/2007 4:32:25 PM GMT
·
I asked, because that’s where my interests are. I own a small engine dyno that even Zenoah (Japan) is envious of. With the Air Force wanting "Heavy Fuel" (Diesel) drone engines, I thought there would be more people doing diesel engines in Bots similar to yours. Maybe someday I’ll build a diesel powered BOE-BOT or Sumu Bot, that would be way·cool.
·
In the past I’ve mentioned my model airplane project, (naturally I like drones too). Here is a picture of our Ashley powered·by a ·ZDZ 160 cc and Zenoah GT-80 powered Kelly F1-C and the Dyno (btw, that's not me in the pic)
Post Edited (Capt. Quirk) : 3/16/2007 1:43:42 AM GMT
I know they are messy and perhaps not as controlable for small bots, but it would just add to the challange and fun. Many larger engines are avaliable cheap and·easily less expensive than any electrical powerplants for the larger battle bots that allenlane5 was talking about. But they can certainly be made to produce long flat torque curves.
Ken, instead of that Honda, Look at the Zenoah G25 Geo engine. less weight, 100 miles to a gal., California smog legal and excellent low·rpm, torque·power band. (Much better than the Honda)
Good idea. I'm also interested in drone airplanes. You can see one of my GPS Datalogger applications in the Parallax video library. It's just a logger, but you could use it for autonomous flight with some adaptation. See the "Remote Control Project" video at http://www.parallax.com/html_pages/resources/videolibrary/resources_product_library.asp.
I've seen the Zenoah engines before. Maybe I'll give one of those a try on my next project. The Honda weedwacker engines have a narrow power band around 4-5K RPM, as you indicated.
Ken Gracey
Parallax, Inc.
·I have dyno runs of the GEO, I spent a lot of development time with that engine. And more runs on the G23lh, G230rc, G260rc, Fuji BT50 and GT74 & 80 engines.
I just took a second look at those·links again, I new the first one was the 30 or 35 cc 4 stroke. But the second one isn't, how big is it?
But it had·three modes of operation using straight electric drive or gasoline drive with electric steering or a combination of both power sources for maximum performance.
·It would be interesting to build a long range Diesel/Electric platform. That's probably a good way to build a Scout bot. You could chug along under diesel·fuel power for·say 50·miles·while charging the batteries and then switch to whisper mode·by using electric power for the last mile or so·to sneek up on whatever you wanted to observe without detection..
Of course· fossil fueled automobiles are also becoming more and more robotic and they may eventually not require a driver for everyday grocery getting and commuting. The last DARPA challange demonstrated that the systems required are possible.··But they still need a lot of refinement.
Big robotic vehicles are comming and many of them will still be slurping up those pesky Dinosaurs until a lot better long range·power source is developed and mass marketed.
Heres a heavy fueled autonomus bot for you to ponder.
http://linuxdevices.com/news/NS5782785656.html
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Team K.I.S.S
Build Safe, Build Mean, Build Strong!
Post Edited (slamer) : 3/16/2007 2:25:14 AM GMT
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Thank's Brian
www.truckwiz.com
·"Imagination is more important than knowledge..." ·· Albert Einstein
Post Edited (Brian Beckius) : 3/16/2007 12:32:29 PM GMT
I'm thinking about building a dyno , what are you using to load the motor ?
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Thank's Brian
www.truckwiz.com
·"Imagination is more important than knowledge..." ·· Albert Einstein
The HUFF Dynos are not as sophisticated as a Super Flow, But it is a fully automatic dyno. The Huff dyno has a real time weather station and a temperature controlled dyno room and dual monitors. Set the sweep rate, begin and end test parameters and hit a switch and let it go, Scans / Sec of the dyno's strain gauge and sensors depends on your·DAQ card and your operating system, mine is set for 100 scans / sec with 30 to 40% of those resources are dedicated to just the load cell.··
The Huff dyno is a "Hydraulic Brake" dyno and the best feature of this dyno is it's accuracy in both an up sweep and down sweep. The # are soo close that a Super Flow or a Land & Sea can't match it. The Huff dyno is arguably better than many "Eddy Current" dynamometers too.
The least expensive and least accurate dyno is an "Inertia Dyno", But it's is an easy project with any style·Stamp. The limiting factor with which processor you·choose will be RPM or actually RPS (revs per sec) and the amount of measurements you record per revolution, the simplest set up would be 1 per 360 deg of rotation. You determine the torque by measuring the acceleration of a known mass in radians/sec/sec. This style dyno could be done with a hall sensor or an optical encoder and a balanced piece of aluminum or steel and somewhat simulate what your testing (say a go-kart) by using F = M*A.
The real advantage of these dyno's isn't the measurement of Torque and Horsepower, but Acceleration (f=m*a again) The Torque (and HP) vs. TIME, not RPM is it's strength and used in conjunction with a "Brake" style dyno (for accuracy)·can lead to product that substantially out performs the competition.·
Post Edited (Capt. Quirk) : 3/20/2007 5:55:10 AM GMT
http://www.surpluscenter.com/item.asp?Item==10-2345&UID=2007032021505743
PS. ·2 months ago nuts and volts had a awsome article on testing dc motors (dyno).
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Thank's Brian
www.truckwiz.com
·"Imagination is more important than knowledge..." ·· Albert Einstein
Post Edited (Brian Beckius) : 3/21/2007 3:45:51 AM GMT
·
The first picture I uploaded is a 2.5cc (.15 ci) RC Car engine using a RC airplane starter motor, setup as a generator. Has a simple encoder to keep track of rpm and I believe a multi-meter, but if he had used a voltage and an amperage transducers and log it to a EEPROM with a time stamp or packet or use the··http://www.parallax.com/html_pages/downloads/software/software_plxdaq.asp it would be much improved.
·
I think the RC Electric Model airplane guys have a lot of information on this subject, from dyno's like this to good simulation software (it's my opinion the RC modelers are ahead because it's been more popular for a longer period than BOTs) Do a search, Maybe check http://www.rcuniverse.com/
·
Then there is a fine example of a Inertia Dyno and my all time favorite dyno picture. A liberty engine from an old Curtis Jenny biplane.
·
Post Edited (Capt. Quirk) : 3/21/2007 7:19:56 AM GMT