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-   -   [FTC]: New Tetrix Parts (http://www.chiefdelphi.com/forums/showthread.php?t=86960)

Andrew Remmers 26-09-2010 01:55

[FTC]: New Tetrix Parts
 
Thought I would share this if anyone wasn;t aware.

Today the new parts in the Tetrix kit were released.

New parts consist of:

Continuous Rotation Servo
Tread Rubber Inserts
Tread Conveyor
Tread Idler Wheels
Tread Sprocket
Tread Links
Tread Kits
4" Omni-Wheels
Tread Accessory Pack (which I am having trouble figuring out what is in this "pack")

The link is below

http://parts.ftcrobots.com/Default.aspx?bhcp=1

Hope this helps

Andrew

Tony Allen 26-09-2010 10:14

Re: [FTC]: New Tetrix Parts
 
The Tread Accessory pack will consist of paddel's for turning your tread system into a conveyor and rubber inserts for the treads. Also a new thermal protected DC Motor power cable will be an added as a new part.

iblis432 30-09-2010 09:32

Re: [FTC]: New Tetrix Parts
 
I noticed that the continuous rotation servo does not have position feedback. Am I correct in understanding this means that I can only tell the servo to go forward or backward and not to go to a specific point? Or am I misunderstanding what this means.

Aren Siekmeier 30-09-2010 10:12

Re: [FTC]: New Tetrix Parts
 
Quote:

Originally Posted by iblis432 (Post 975573)
I noticed that the continuous rotation servo does not have position feedback. Am I correct in understanding this means that I can only tell the servo to go forward or backward and not to go to a specific point? Or am I misunderstanding what this means.

Seems that it's not much of a servo without position feedback.... I don't know...

EricVanWyk 30-09-2010 10:19

Re: [FTC]: New Tetrix Parts
 
Quote:

Originally Posted by iblis432 (Post 975573)
I noticed that the continuous rotation servo does not have position feedback. Am I correct in understanding this means that I can only tell the servo to go forward or backward and not to go to a specific point? Or am I misunderstanding what this means.

Your understanding matches mine.

We did this to a couple position servos when I was in highschool. Basically, you break the internal feedback loop and remove the hard stops and it turns into something that approximates a normal motor.

I agree that it likely doesn't deserve the "servo" moniker at this point: It looks like a servo, talks like a servo, but doesn't quack like one. Not sure what I would call it. "Motor with integrated control electronics" doesn't sound as sexy as "continuous rotation servo"

biojae 30-09-2010 19:19

Re: [FTC]: New Tetrix Parts
 
Quote:

Originally Posted by EricVanWyk (Post 975580)
Your understanding matches mine.

We did this to a couple position servos when I was in highschool. Basically, you break the internal feedback loop and remove the hard stops and it turns into something that approximates a normal motor.

I agree that it likely doesn't deserve the "servo" moniker at this point: It looks like a servo, talks like a servo, but doesn't quack like one. Not sure what I would call it. "Motor with integrated control electronics" doesn't sound as sexy as "continuous rotation servo"

I tend to call them miniature speed controllable geared motors.
(At least the parallax ones are speed controllable, I have no idea about these ones)

PhilBot 01-10-2010 08:48

Re: [FTC]: New Tetrix Parts
 
Quote:

Originally Posted by biojae (Post 975692)
I tend to call them miniature speed controllable geared motors.

The speed control on a "hacked" servo is crude at best. Most really ARE just a gear reduced motor in an easilly mountable container.

It depends on whether they just removed the mechanical stops/feedback, or changed the drive circuit :)

What IS certain is that there is no position feedback.

Phil.

biojae 01-10-2010 14:20

Re: [FTC]: New Tetrix Parts
 
Quote:

Originally Posted by PhilBot (Post 975759)
The speed control on a "hacked" servo is crude at best. Most really ARE just a gear reduced motor in an easily mountable container.

It depends on whether they just removed the mechanical stops/feedback, or changed the drive circuit :)

What IS certain is that there is no position feedback.

Phil.

I have only dealt with the parallax continuous rotation servos, those are speed controllable.

It would be nice if these ones could be speed controlled.

Chris is me 01-10-2010 14:35

Re: [FTC]: New Tetrix Parts
 
This is not a facetious question; I know of an FTC team that's actually looking for the answer to this.

Are the new tank treads close enough to the Vex tank treads in size, shape, etc. that they can use the Vex tank tread links in their place? I think the rules permit "duplicates" like that. They're looking to save a little bit of cash for a particular feature and want to only buy the sprockets, and they look similar enough that I figure it's worth asking, but since I / they don't have any new tread material in hand they can't really compare the two.

Andrew Remmers 01-10-2010 15:13

Re: [FTC]: New Tetrix Parts
 
Sadly the rule with using VEX parts in FTC was removed last year. Using VEX tread would be illegal even if they had the same size link.

"g. Vex parts of any type are not allowed."

Sorry for the bad news on that aspect.

But what they could do is look for a sponsor or something to donate some money. We got $1800 donated from things that were in our build space for FRC.
I agree that FTC parts are a little on the expensive side, which is why our team tries to avoid modifying them at all cost.

Andrew

Chris is me 01-10-2010 15:20

Re: [FTC]: New Tetrix Parts
 
That's a bit disappointing. I thought I read a rule about "identical replacement parts" or something, but after a second read through I can't find it. There goes $70...

gblake 01-10-2010 15:23

Re: [FTC]: New Tetrix Parts
 
Quote:

Originally Posted by PhilBot (Post 975759)
...What IS certain is that there is no position feedback.

OK - I'll ask... Can anyone tell me why they would call this gizmo a "Servo" instead of calling it a motor? Maybe to pander to some RC enthusiasts that call any motor (except the main drive motor for a vehicle) a Servo? I'm confused.

Quote:

Originally Posted by Joyride_67_1902 (Post 975808)
Sadly the rule with using VEX parts in FTC was removed last year. Using VEX tread would be illegal even if they had the same size link....

Do the currrent rules allow replacement parts of any sort?

Blake

biojae 01-10-2010 15:29

Re: [FTC]: New Tetrix Parts
 
Quote:

Originally Posted by TETRIX® Continuous Rotation Servo
Featuring fully proportional forward and reverse speed control

http://parts.ftcrobots.com/store/det...01&c=0&t=0&l=0

It appears that the FTC continuous rotation "Servos" are speed controllable.

Andrew Remmers 01-10-2010 17:04

Re: [FTC]: New Tetrix Parts
 
Quote:

Originally Posted by Chris is me (Post 975809)
That's a bit disappointing. I thought I read a rule about "identical replacement parts" or something, but after a second read through I can't find it. There goes $70...

If we could use identical parts I'd think we would just buy gear stock instead of gears from Tetrix. We however can use identical hardware from anywhere in any length which will come in handy im sure.

Andrew Remmers 01-10-2010 17:08

Re: [FTC]: New Tetrix Parts
 
Quote:

Originally Posted by gblake (Post 975811)

Do the currrent rules allow replacement parts of any sort?

I'm guess I'm having a hard time interpreting what you mean by replacement.

Do you mean like a spare part in tetrix kit, or something that does the same thing even looks the same from out of kit?

gblake 01-10-2010 18:02

Re: [FTC]: New Tetrix Parts
 
Quote:

Originally Posted by Joyride_67_1902 (Post 975828)
I'm guess I'm having a hard time interpreting what you mean by replacement.

Do you mean like a spare part in tetrix kit, or something that does the same thing even looks the same from out of kit?

Same size, shape, mass, surface finish, function, etc. parts gotten from a retailer/OEM other than Pitsco/Tetrix (I'm not sure if either Pisco or Terix are OEMs, but let's give them the benfit of the doubt in this conversation). The classic example is substitute screws bought from a local hardware store.

"Substitute" would have been a better choice of words on my part.

Blake

Andrew Remmers 01-10-2010 18:23

Re: [FTC]: New Tetrix Parts
 
Quote:

Originally Posted by gblake (Post 975835)
Same size, shape, mass, surface finish, function, etc. parts gotten from a retailer/OEM other than Pitsco/Tetrix (I'm not sure if either Pisco or Terix are OEMs, but let's give them the benfit of the doubt in this conversation). The classic example is substitute screws bought from a local hardware store.

"Substitute" would have been a better choice of words on my part.

Blake

Generally the rules has been No you can't. You have to use tetrix parts or anything that they specify that can be used. Otherwise there isnt much straying from the kit sadly...


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