Drive systems

Hi,

I am relatively new to the forum, but thought its about time I introduced myself.

Im an electrical engineer for a living (degree in mechanical/chemical engineering) working on electrical systems for buildings.

Got a son who is mad on Robots and getting to the stage where weve bought the remote control, put together a few ant weights by modifying a few servos etc.

To be honest, Im a bit stuck at this point in time. Coming down from 11KV/400V/230V to this size is a little way out from what im used to.

I am currently looking at a reasonable drive system (Motors and speed controllers) which can be used as the base for a half decent featherweight.

Just wondering if you guys had any suggestions on which motors would work well with certain spped controllers. Also battery size and type.

Regards

Andy

Welcome to the forum Andy,

Drive motors - I would recommend drill motors as these come with a suitable gearbox and many ready made mounts and wheels are available via members of the forum. These attach directly to the drill motors and provide lightweight powerful drive units.

speed controllers - There are a number of options available,

- electronize (technobots.co.uk) - Very good controllers with very few problems that will easily handle drill motors (look to the 15A processor controlled units).

-Sabertooth 2x25 speed controller (gimsonrobotics.com) - No experience with these but the specs are very impressive

- robotpower scorpion XL (xbotz.com) - Again I have no experience with these and the specs arent as high as the sabertooth controllers but many robots have been successfully run with them.

With batteries you have a number of options available -

Sealed Lead Acids (around the 2.2 to 3Ah range) - heavy but reliable. Not used in many competitive bots anymore.

nicads - These are better for bursts of current. I use nicads in my spinning disc featherweight and they happily allow 50 to 60 amps draw bursts (they do get quick toasty)

nimh - Better for constant draws however many brands are heading towards being just as good as nicads in terms of burst currents.

lithium technology - I would stay away from this area completely for a new featherweight.

I hope that that helps!

Welcome to this very addictive hobby.

This question is asked a few gazillion times, but, Ill give my point of view.

The Hannibalito series of feathers use for drive the common Graupner Speed 900BB torque motor. With a mod1 Z12 gear on the motor, and a gearratio 4.5 to 1 (Z54 on the wheel). The wheels are custom made, and have different diameters, but were prefering around 80mm diameter.

Batteries, NiMH 10 cell stickpack with Sanyo 3600mAh or the GP 3700mAh . We also have a 4 cell A123 pack, but those arent approved yet for the use in feathers by the organisation.

Speedo, we used the expensive overkill speedo the Sidewinder.(we also use that in the heavies). But now the Scorpion XXL is taking that role.

But the easy way out, for acceptable money is to use batterydrill motors and gearboxs. A lot of succesfull machines use this.

It all depends on price and performance.

Best bang for your buck:

Drillmotors and Scorpion XL or Sabretooth, with the blue wheels (They are really good wheels for feathers), and 18V Nicads for the batteries. NiMh is also an option but more expensive and more maintenance prone.

Higher priced, more performance:

Speed 900 BB Torque motors, own made gearbox, Blue wheels, Scorpion XXL (They are also 2x25A Gary) or Sabretooth 2x25A or even Sidewinder, on 24V Nicad or NiMh.

Riduculous amount of torque and speed:

2 Astro Cobalt 90 motors, blue wheels, custom gear reduction, 24V NiCad, Sidewinder or small Vantec speed controller. Good luck keeping that on the floor. It is what I refer to as the obscene power drive for feathers. But it is not cheap.

im already having major trouble getting the power of the 2 Speed 900 (at 24v) in BonX on the ground.

Putting in Astros would just be a shamefull waste of money, theyll do fine as spinnermotors though.

spend your money on something more usefull, like a weapon...

Tim, the only reason why we use the heavy speed 900s is because they have good torque for a good rpm range.
The fact they are hugely overpowered in total for a feather is a sideline in that equation.
But yes, even on 7.2V they have enough power for a feather. (and still have a usefull RPM of 4000)

The Astros are a good motor to build a featherweight Storm II. (but so are the speed 900s)

Thanks for the responses guys. I suppose until I actually get them in front of me itll all be a bit unclear. I had been considering the electronize speed controllers anyway but had absolutely no experince on the at all.

On the speed controller, there are two types. One with a 5v output for the receiver and one without. Any opinions on these?

As far as the motors are concerned, there is a massive variety of motors and gear boxes available, many different gear box ratios and so on.

Maplins do a range of the combo drills motors. Any ideas what sort of speed (rpm) they should be doing?

Gary said that a range of wheels and ready made mounts were available from members of the forum. If anyone wants to stick their hands up and tell me who they are, we can sort it out.

Thanks again for the help so far

Regards

Andy

I do have several options of drives available. but non are as cheap as a batterydrilldrive. Rather expensive compared to those even.
I can be contacted in several ways. PM, MSN or Email.

But for rpm. That is dictaded by wheel diamter and wished for speed. And speed is dictated by your motorpower, in the end.
Aim between 12-15km/h (8-10mph) for a drill based drive (faster is possible, but will eat amperes)
25 mph is no sweat for the high torque Speed 900s I regulary use.

has anyone had any experiance of these motors?

http://www.maplin.co.uk/Module.aspx?ModuleNo=43368&&source=14&doy=12m10http://www.maplin.co.uk/Module.aspx?...e=14&doy=12m10

Those are the same motors and gearboxes used in the Zeobot class that Technobots sells.

http://technobots.co.uk/acatalog/info_7020_500.htmlhttp://technobots.co.uk/acatalog/info_7020_500.html

They are ok for the zeobot kits, but in a combat situation I wouldnt rely on them. The gearbox and axle are pretty weak.

Andy,

Get in contact with Grant or James cooper for wheels and mounts. The blue wheels they have are used in a large number of featherweights in the UK.

The 5v output electronize has what is known as a BEC (battery eliminating circuit). This is able to supply your receiver with power from your main set of batteries without the need for a seperate smaller set battery pack. Receivers typically work in the range 4 to 6v.

Adrian,

I have had limited experience with those motors in another project. They look similar to the motors used in the zeobots kits so perhaps you should find someone that had one of those kits or get in contact with technobots. You have to be careful which motors you use as there are a large number of variations (voltage etc).

when i first had my zeobot kit, i used these motors, at the time they did the job however i dont think unless you over volt them and vcreate some decent hubs, that they will be any good

but if you are looking for some with wheels drop me an email, have 2 used ones

Is there a better drive system for the weight than this Banebot gearmotor http://banebots.hostasaurus.com/pc/MP-36XXX-545/MP-36025-545http://banebots.hostasaurus.com/pc/M...5/MP-36025-545 ?

for the weight, sure

you wont like the price though. :)

I perfectly can imagine/build better drives.

It just depends on $$$.

What drives could you imagine or build for 354 grams? Do you have any links to these drives?

Thanks

Nope, Ill have to design and build them first before pictures or links will excist.

(Message edited by maddox on November 07, 2007)

you can think Astros, sensored brushless, etc..