Team Update - 4/2/2013

[Hallry]

Taken from the FRC Manual, 4/2/2013: http://frc-manual.usfirst.org/Updates/0#term 103

Game Manual - Team UPDATE - 2013-04-02
The ARENA
The FIELD

The FIELD for ULTIMATE ASCENT is a 27 by 54 ft. carpeted area, bounded by ALLIANCE WALLS, FEEDER STATIONS, LOW GOALS, and GUARDRAILS. The FIELD floor is covered with carpet (Shaw Floors, Philadelphia Commercial, Neyland II, 20, 30550 (NOT 30753), “Ground Pepper”). Three (3) GOALS are located at each end of the FIELD above each ALLIANCE WALL. A fourth GOAL and three (3) FEEDER STATIONS are located in the corners next to each ALLIANCE WALL. A PYRAMID is adjacent to each ALLIANCE’S AUTO LINE. At the top of each PYRAMID sits a PYRAMID GOAL. Each LOADING ZONE is a trapezoidal area bounded by two (2) FEEDER STATIONS, an ALLIANCE WALL, a GUARDRAIL, and Red or Blue tape.

Power Distribution
R51

While the two versions of the Talon have similar functionality, there are some differences teams should be aware of. Please see http://www.crosstheroadelectronics.com (http://www.crosstheroadelectronics.com/) for more information.

The only power regulating devices for actuators permitted on the ROBOT include:

Jaguar motor controller (P/N: MDL-BDC, MDL-BDC24, and 217-3367),
Victor 884 motor controller (P/N: VICTOR-884-12/12),
Victor 888 motor controller (P/N: 217-2769),
Talon motor controller (P/N: CTRE_Talon, CTRE_Talon_SR, am-2505 and am-2195),
VEX motor controller (P/N: 276-2193) for controlling VEX 2-wire Motor 393 (P/N: 276-2177) only, and
Spike H-Bridge Relay (P/N: 217-0220 and SPIKE-RELAY-H).

[joelg236]

Synchronous sign magnitude rectification

What does this mean in practicality?

[sanddrag]

What does this mean in practicality?It seems to me that it would not only provide inverse reactive current for use in unilateral phase detractors, but would also be capable of automatically synchronizing cardinal grammeters.

[ablatner]

It seems to me that it would not only provide inverse reactive current for use in unilateral phase detractors, but would also be capable of automatically synchronizing cardinal grammeters.

Do you think it also has a base-plate of prefabulated amulite, surmounted by a malleable logarithmic casing in such a way that the two spurving bearings were in a direct line with the pentametric fan?

[Steven Sigley]

http://www.youtube.com/watch?v=lBp5ag6SJH4

this thread...

[lorem3k]

What does this mean in practicality?
According to AndyMark:
Major change due to sign-magnitude synchronous rectification is the improved efficiency at stall, resulting in a lower need for a heat sink.

[RufflesRidge]

According to AndyMark:

I believe it should also behave much better in a Bang-Bang control scheme.

[Bill_B]

What does this mean in practicality?

You're not inspired to investigate how an H-bridge works? Drat! We've failed FIRST's mission once again! :) ;)

[dtengineering]

What does this mean in practicality?

Ooh! Ooh! Ask me! Ask me! (http://modularcircuits.tantosonline.com/blog/articles/h-bridge-secrets/) (edit: this is, honestly, a link to a blog post that explains the whole thing at a reasonably technical level)

Actually I had to re-read that article a few times before I "got it" and would still have a hard time summarizing it any better than some of the previous posts, but if you don't have anything better to do (like, say, getting ready for the first regional to be held within 1,000km of your home town) it is a good read and pretty well explained.

Jason

[David Brinza]

I really can't tell you how many times we've been bitten by sinusoidal depleneration until we learned about the Allen-Bradley Retro Entabulator.

Rockwell Automation provided a timely solution to a previously unknown and un-encountered problem.

[Grim Tuesday]

Let me just whip up a GUI in visual basic! (http://www.youtube.com/watch?v=hkDD03yeLnU)

[Mike Copioli]

In a nut shell;

The Talon reverses the output polarity to the motor every off period of the duty cycle.

The Talon SR simply "Brakes" during the off period of the duty cycle. This is type of rectification that the Jaguar uses.

This type of rectification produces less heat at the Talons input capacitor during stall.

It does not change the linearity or maximum output power. It does however produce significantly less heat during motor stall.

[Racer26]

In a nut shell;

The Talon reverses the output polarity to the motor every off period of the duty cycle.

The Talon SR simply "Brakes" during the off period of the duty cycle. This is type of rectification that the Jaguar uses.

This type of rectification produces less heat at the Talons input capacitor during stall.

It does not change the linearity or maximum output power. It does however produce significantly less heat during motor stall.

Correct me if I'm wrong Mike, but will the SR not behave differently on a non-level surface (like the 2012 bridges) in terms of controlled descent?

[Mike Copioli]

Correct me if I'm wrong Mike, but will the SR not behave differently on a non-level surface (like the 2012 bridges) in terms of controlled descent?

The behavior during the off period is to decay the fly-back/freewheeling current from the motor. Instead of redirecting the current back into the system like the Talon, the Talon SR simply connects the motor leads together. The observed mechanical behavior for both open and closed loop control among both devices is almost identical.

Both methods result in a very rapid decay of flyback current.

[Racer26]

TL;DR version: yes, technically they're different, but in practice it has little tangible effect. Cool