Create Driving

10 replies [Last post]
Harrison Cassar
Title: NooBot
Joined: 10/16/2013
Posts:
BotPoints: 197
User offline. Last seen 2 years 43 weeks ago.

Hi everybody of the Botball Community, this is Harrison again. I was wondering if any of you know if there is any relation between the speed of which the Create is going to rotations per minute of its wheels. If somebody can reply there thoughts or what they heard in rumors, that would be great.

Also, if anybody has done any experiments on this already, may you please post about them? I would love to hear about them.

Thanks!

Jesus Arzapalo
Title: NooBot
Joined: 10/23/2013
Posts:
BotPoints: 82
User offline. Last seen 1 year 22 weeks ago.

Of course there is a relation, you just have to find the circumference of the wheels, how fast the create is going, and the rotations. It depends what the speed is measured in. If you measure the circumference in centimenters you have to find the speed in meters per minute. I don't know if I'm right but this seems interesting, we should research this. I will look into it later.

Harrison Cassar
Title: NooBot
Joined: 10/16/2013
Posts:
BotPoints: 197
User offline. Last seen 2 years 43 weeks ago.

@Jesus Arzapalo: Yeah, I was planning on this week testing out this relation. However what I was meaning by "does anyone know if there is a relation" is that have anybody done experiments already and if so, is the speed proportional to the rotations per minute?

Thank you for the feedback though; it will still help the progress of this large experiment.

Thanks!

ruler501
ruler501's picture
Title: NooBot
Joined: 01/29/2012
Posts:
BotPoints: 367
User offline. Last seen 2 years 30 weeks ago.

There will definitely be a relation(my guess would be linear unless you are on a really slick surface where there is slipping). That is just basic physics. Don't you control the create with mm/s speed though? Are you trying to work back from this to rotations per minute? I'd also like to see what you plan on doing with that since I cannot see any obvious way it is needed.

YuSheng.Chen
Title: NooBot
Joined: 10/28/2013
Posts:
BotPoints: 286
User offline. Last seen 3 years 43 weeks ago.

Actually, it will not be linear because of the frequency of voltage spikes as you increase the power exerted on the wheels. It would be more parabolic if my guesses are correct. And, neither have I actually tested this.

ruler501
ruler501's picture
Title: NooBot
Joined: 01/29/2012
Posts:
BotPoints: 367
User offline. Last seen 2 years 30 weeks ago.

That would be a comparison between voltage/power and speed though. It is simple to show with physics that the relation will be linear if the friction(traction) is high enough.

YuSheng.Chen
Title: NooBot
Joined: 10/28/2013
Posts:
BotPoints: 286
User offline. Last seen 3 years 43 weeks ago.

Yes, in physics, it would be linear, but, you cannot ignore power in robotics. Even though we are only talking about so and so doesn't mean other factors don't come into play.

ruler501
ruler501's picture
Title: NooBot
Joined: 01/29/2012
Posts:
BotPoints: 367
User offline. Last seen 2 years 30 weeks ago.

the relation between power being applied may not be linear and is probably not considering power wasted is I^2R and power used(probably not at 100% efficiency) is IV. My guess is there is a leveling off of power output as you apply more power that is less than linear. They were asking relation between wheel rotations and speed and that is what I was commenting on. If you want to look at how the power works that is a lot more technical and would require looking at the circuits and specifications that go along with them.

YuSheng.Chen
Title: NooBot
Joined: 10/28/2013
Posts:
BotPoints: 286
User offline. Last seen 3 years 43 weeks ago.

I am fully aware of that. I am just pointing out a fact that should not be ignored. I am not saying that you commented wrong or anything. Yes, I know, I am at wrong. I shouldn't have pointed out power but, it cannot be ignored in practical applications.

zoha3492
Title: NooBot
Joined: 10/23/2014
Posts:
BotPoints: 2
User offline. Last seen 3 years 7 weeks ago.

Hello, It's Amanda from PDCMS. How are you guys liking the new Botball game? I personally think it's a challenge in its own way, like the hangers. Another question, if bot guy wants to get in shape, why hangers?

zoha

bonnienichols
Title: NooBot
Joined: 03/07/2014
Posts:
BotPoints: 52
User offline. Last seen 1 year 36 weeks ago.

we can find rotational speed by a relation ω = v / 2πr. Second law of motion tells us F=ma. Is this is not useful for finding the speed proportional to rotation. Later if you can find by any experiment please tell me also.

free pokies