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Mr-Olsson
03-11-2007, 12:34 PM
Hello! I'm planing on building a PC-based robot in the future and trossen is most likely to be the shop were I will buy the hardware. Anyway.. I need some help and I have written almost everything in my thread on the botmag forums: http://www.botmag.com/forum/showthread.php?p=1765#post1765

I'm sorry I don't have the power to rewrite it here right now. :o But I could copy It and paste if there are someone who don't mind reading a thread from another forum.;)

Very thankful for any help!

Alex
03-12-2007, 09:19 AM
Hi Mr-Olsson!

Welcome to the community. It's awesome to hear about yet another PC-based robot project!

We don't mind reading a thread from another forum. It's all about starting a robotics community: Congregation, not Segregation;)

You'd probably get better results with others helping you though if you copy and paste your thread from another forum. It's just that it makes it a lot easier for other members to find your thread.

Mr-Olsson
03-12-2007, 12:24 PM
Thank you Alex for the warm welcome!

I agree completely! Here it is:

"I have done a lot of thinking and reading on that trossen robotic shop and in my Robot magazines. But I'm not sure exactly what hardware I'm going to use. I thought about using the exact same motors and servos as the one used by Matt and Peter in the PC based Robots article in Robot issue 4 and 5, just to avoid eventually problems and.. they are kinda cheap too! So what do you think? Bet i can get a lot of help from the experienced roboteers here on the forums and I don't think i can manage without it! :D So.. this is going to be a big project for me and the robot are going to be pretty heavy i think (with all the hardware I want for it) so any comment on the hardware? I don't want to buy something that doesn't work in the long run. Any more help would be awesome!;)

The hardware that i might be using:

4-Servo Phidget USB Servo Controller -$67.50
http://www.trossenrobotics.com/store...ontroller.aspx (http://www.trossenrobotics.com/store/p/3188-Servo-4-Motor-Controller.aspx)

AC wall adapter 6V Power Supply - $14.40
http://www.trossenrobotics.com/store...upply-USA.aspx (http://www.trossenrobotics.com/store/p/3442-Power-Supply-USA.aspx)

BaneBots 45A Peak Motor Controller - $57.00$ x 2
http://www.trossenrobotics.com/store...45A-peak-.aspx (http://www.trossenrobotics.com/store/p/4267-BaneBots-Motor-Controller-45A-peak-.aspx)

25:1, 36mm Planetary Gearmotor, RS-545 Motor - $38.95 x4
No Load RPM: 624 rpm
http://www.trossenrobotics.com/store...545-Motor.aspx (http://www.trossenrobotics.com/store/p/4238-25-1-36mm-Planetary-Gearmotor-RS-545-Motor.aspx)

(Not sure about batteries.. In the first article the Gel Cell Zeus was used but with only 7.2AH. In the later article a Werker with 12 Ah was used, almost like the one below i think.)

Hoveround 12 volt 12 Ah SLA Battery - $35.95 x 3
http://www.lowcostbatteries.com/Scoo...2volt-12ah.htm (http://www.lowcostbatteries.com/Scooter-Batteries/Hoveround/12volt-12Ah_p/12volt-12ah.htm)

or..

Gel Cell (12V 7.2AH) Zeus - $18.00 x 3
http://www.trossenrobotics.com/store...-2AH-Zeus.aspx (http://www.trossenrobotics.com/store/p/3448-Gel-Cell-12V-7-2AH-Zeus.aspx)

More things will eventually be needed. But that's it for know.
Anyway.. I do have a couple of questions, so i list them so that they can be more easily answered. (It's mostly about the upper mentioned hardware.)

1. So i might use three batteries, one for the electronics, one for the PC and one more for lights and other accessories. What do you think? Any suggestion about some other lead-acid batteries that might be better to use?

2. The robot will weight, do you think four RS-545 Motor with 624 rpm no load will handle that in a good speed? I would love to use even better and faster motors as they don't seem to cost too much more really. :D And what about the sound, will they sound very loud?

3. For good steering in for example small places, would four or three wheels be better too choose? Like two wheels with motors and one behind in the middle so that the robot could spin instead of steering like a car. Not sure on this though.. Four wheels would of course handle more weight.

I think that will do for now.. Hope at least something can be answered. It's not that I'm compete new new to all this, but almost so it would be great if someone with experience could help a little bit. Thanks!"

Hope that made it easier! Now please feel free to comment anything. :)

Dave
03-12-2007, 03:43 PM
1. So i might use three batteries, one for the electronics, one for the PC and one more for lights and other accessories. What do you think? Any suggestion about some other lead-acid batteries that might be better to use?
You'll have to experiment a bit to find the right battery solution for your bot. My suggestion is to start out with two 12 Amp-hour batteries, because that would be enough to run the motors, computer, and other electronics for at least 2 or 3 hours.



2. The robot will weight, do you think four RS-545 Motor with 624 rpm no load will handle that in a good speed? I would love to use even better and faster motors as they don't seem to cost too much more really. http://www.botmag.com/forum/images/smilies/biggrin.gif And what about the sound, will they sound very loud?
That's a good gear motor, but if you're concerned about noise, you may want to go with a different choice. The one you picked is being discontinued, and this one is replacing it:
http://www.trossenrobotics.com/store/p/4928-25-1-36mm-Planetary-Gearmotor-RS-540-Motor.aspx
The gearboxes are constructed a little better now, which improves energy transmission and cuts down on the noise.



3. For good steering in for example small places, would four or three wheels be better too choose? Like two wheels with motors and one behind in the middle so that the robot could spin instead of steering like a car. Not sure on this though.. Four wheels would of course handle more weight.

A three-wheel design would be nice and simple, but each of those batteries weighs almost 10 lbs, so you should probably go with 4 wheels so you can spread the weight out more.

Steering with 4 wheels isn't really a big deal. You can use a differential (tank-style) drive system so you still have a 0 degree turning radius.

Mr-Olsson
08-12-2007, 05:01 PM
First of all, thank you Dave for your great advices. Second - I'm sorry for the late answer..

I have thought a lot about this project and I've decided to do it. It will surely be something great with the hardware from Trossenrobotics and some help from the experienced people here on the forum. :)

So about the hardware again...

Do you still recommend this motor: http://www.trossenrobotics.com/store...540-Motor.aspx (http://www.trossenrobotics.com/store/p/4928-25-1-36mm-Planetary-Gearmotor-RS-540-Motor.aspx) or are there any newer better? Just curious.. I've seen a lot of robots wheeling around sounding like a toy RC car, really don't like that so those less noisy motors sounds fantastic.:)

Another thing that worries me is robot navigation with DC-motors. For example if the robot is suppose to calculate it's own x,y,z-coordination will a stepper motor be necessary or will it be possible with regular DC-motors like BaneBots?

And last.. In Robot mag issue 6 spring 2007 there was a note about a customizable robot chassis made in partnership with BaneBots, are there any left? I can only see the Extra Level Kit in the shop. It looks so very perfect for a PC-robot project. :D

Once again I'm very thankful for any help!

*Patiently waiting*

Dave
08-22-2007, 10:26 AM
Do you still recommend this motor: http://www.trossenrobotics.com/store...540-Motor.aspx (http://www.trossenrobotics.com/store/p/4928-25-1-36mm-Planetary-Gearmotor-RS-540-Motor.aspx) or are there any newer better? Just curious.. I've seen a lot of robots wheeling around sounding like a toy RC car, really don't like that so those less noisy motors sounds fantastic.:)


If you're concerned about noise, you could enclose the undercarriage of the robot. Just putting a box around the drive system can cut the noise down significantly. I'd say "use smaller motors" but it sounds like your bot will be heavy... It's always a trade-off.



Another thing that worries me is robot navigation with DC-motors. For example if the robot is suppose to calculate it's own x,y,z-coordination will a stepper motor be necessary or will it be possible with regular DC-motors like BaneBots?
Encoder:
http://www.trossenrobotics.com/store/p/5069-Encoder-36mm-Gearbox-Mount-Full-kit.aspx

Phidgets USB encoder interface:
http://www.trossenrobotics.com/store/p/3236-Phidget-Encoder-High-Speed.aspx

These two components will give you a precise measurement of how far each motor has turned, allowing you to track the robot's motion. You lose some accuracy when you're using a 4-wheel system though, because the wheels tend to skid a little bit.



And last.. In Robot mag issue 6 spring 2007 there was a note about a customizable robot chassis made in partnership with BaneBots, are there any left? I can only see the Extra Level Kit in the shop. It looks so very perfect for a PC-robot project. :D
I'm afraid that project has been placed on the back burner, for the time being. We may be clearing out some of our surplus prototype decks as "garage sale" items, though. So stay tuned.

Mr-Olsson
08-23-2007, 02:07 PM
You lose some accuracy when you're using a 4-wheel system though, because the wheels tend to skid a little bit.

Makes me worry.. Do you think it would be worth to have a 3 wheeled robot (with less weight on it) instead just for that reason? I'm curious about how much accuracy you might lose if you can tell.

If I would change to a 3-wheel system a new chassi would be necessary.. (haven't bought anything yet though) Maybe the Trossen1 would be something? Not 3-wheeled and it uses tank-driving though. I welcome any recommendations.

Dave
08-27-2007, 10:54 AM
Actually, the Trossen-1 would be pretty good for what you want to do. It has two drive wheels and casters at the front and rear, so you won't have the skidding problem I mentioned in my last post. It comes with wheel encoders installed, too.

Dave
09-14-2007, 03:47 PM
The Trossen1 base is on sale!

http://www.trossenrobotics.com/store/p/5377-Trossen-1-Chassis-and-Base.aspx

Here's what you get:
(1) Trossen1 chassis (3/16" aluminum deck & drive system)
(2) 12V DC motors
(2) US Digital optical encoders
(4) Noise suppression capacitors
(2) Extra decks (1/8" aluminum)
(16) 2" 8-32 hex standoffs
(16) 1" 8-32 hex standoffs
(8) 8-32 wing nuts
(8) lock washers
(8) 3/8" 8-32 button top hex bolts


This platform was designed way back in the dark days before we were even called "Trossen Robotics." We made about ten prototypes before we deemed the sheer bulk of custom-machined aluminum too costly for us to produce economically. Sadly, the design had to be shelved because of this. All in all, it's a very nice base, and well worth the cash. When you buy one of these, you're not only getting a rugged wheelbot base, you're also getting a piece of TR history!