Speed Controller Preference

[Steven Sigley]

Did your team prefer using Jaguars or Victors last year and why?

We used Victors because we wanted to maximize space for our ball hopper and putting the electronics in a box meant it was easier to fit 9 Victors than 9 Jaguars.

[Billfred]

1618 used four Jaguars. They came in the kit and they worked (our own electrical issues aside).

2815 used, as I remember, four Jaguars and two Victors, also largely driven by availability. Jaguars went on the belts and shooter drums, Victors on the two drive motors.

[ajlapp]

Team RUSH switched to all Jaguars on the competition bot last year in anticipation of being able to use the enhanced features in the near future.

I'm personally very excited about CAN and the opportunity to teach our students about it.

I currently work with CAN on a daily basis in automotive applications....and I'm positive that none of our students even know it exists or how it works inside their vehicles.

[ATannahill]

Team Krunch used four jaguars for drive and four victors for manipulation on our robot. In addition to availability we considered weight and ease of replacement/addition. We had spots made for up to 10 victors on our board.

[Steven Sigley]

Originally Posted by ajlapp

I currently work with CAN on a daily basis in automotive applications....and I'm positive that none of our students even know it exists or how it works inside their vehicles.

Yeah I can honestly say I hadn't the slightest clue it existed until hearing about it when they unveiled the new equipment at Atlanta in 2008.

[daltore]

The ausTIN CANs used 6 Jaguars and 2 Victors. The Jags went to our 3-wheel swerve drive, and the Victors were on our turret and shooter. We also had two Spikes on our lift (one feeding roller and one belt).

Personally, I'm very impressed with the Jaguars, more so than the Victors. We've been careful enough (in general) not to kill any motor controllers this year other than individuals' mistakes, but the Jaguars have kept cooler and provided more consistent and linear power than the Victors. I'm also very excited about using the CAN bus next year, it'll be great to teach serial communication protocols (none are really being taught from the ground up, even in FIRST, all of the networking is embedded deep in the magic boxes).

[biojae]

399 used 2 jaguars for the drive.
The only victor that we had was for the conveyor,
we only really ran it at full speed so the low speed capabilities of the jaguars weren't needed for it.

(We also had a spike for the dumper)

We only broke one jaguar, and it was a defective one.
Powered on and smoke blew everywhere.

[DonRotolo]

Jaguars. They're a little bit bigger, but their output is a Lot more controllable. Color-coded screws are a bit more fool-resistant.

We used 2 Jags and 4 Victors in 2009

[Jon Jack]

During competition season we used 4 Jaguars (2 drive, 1 pickup, 1 dump) and 1 Victor (for the second dump motor). We have to use the one victor simply because we ran out of room and needed a second motor for our dumper to work effectively.

We had no problems with the Jaguars all season...

Then when we started making enhancements for IRI we replaced the 4 Jaguars with 4 Victors. We made this switch because we needed the extra real-estate to make room for traction control hardware. We fit 5 Victors (with room for one more) in the same foot print the 4 Jaguars previously occupied.

We haven't made a determination on what we'll use for 2010 since we don't know what will be available and what our size constraints will be.

[EricVanWyk]

I'm really excited about CAN. I think that about 10% of teams will really dig into it this year, and that they will create some solutions with it that (although not game changing) will make us rethink a few common design memes. Hopefully the year after, newer teams will benefit from "how you CAN make your robot drive straight" tutorials.

I'm not saying that CAN will let you do things that are impossible now, I'm just hoping it lowers the ((entrance)) bar for some of the fundamentals.

[biojae]

Originally Posted by EricVanWyk

I'm not saying that CAN will let you do things that are impossible now, I'm just hoping it lowers the ((entrance)) bar for some of the fundamentals.

Most of the features that the CAN bus allows us to do are easily doable now.
The speed (Voltage) control mode, is the mode we are using through PWMs.
The Analog position input (Potentiometer)
has been done by almost everyone using an arm (PID control)
The Encoder position control
Can be done this year, use a PID controller and have your setpoint be a # of ticks
Limit switches - Digital input,
if(input && (abs(speed)/speed) == limitDirection) motor.set(0.0);
else motor.set(speed);


Though, the real advantage of using CAN is that the Jags handle the monitoring, and control internally.

Which can provide the fastest response possible in a closed loop.
(At least with the motors & controllers we can use)

And any faults can be read by the RIO,
ex: does that red slow blink mean the limit switch has been triggered or is the jaguar dead?
Conditions like: over-current, under voltage (ie 6v from battery), limit switch, or over temperature; can easily be read from like the driverstation LCD instead of guessing.

Also having access to all the motors variables (current, voltage, torque, speed) without having to put in a large coil of wire for a current sensor is nice.


http://www.luminarymicro.com/products/mdl_bdc.html
BD-BDC-DS-01 Datasheet for Brushed DC Motor Control Module

[sanddrag]

We used 8 Victors, simply because Jaguars would not fit, and were not aesthetically pleasing in our design.

EDIT: Also, we already had plenty of Victors from previous seasons, whereas we would have needed to purchase more Jaguars.

[jspatz1]

We used a mix of both. We found the Jags to definitely be smoother and more stable for low speed and position holding. A Victor on our turret drive would cause the turret to twitch with a tremor when trying to hold a position, and not be repeatable when homing to a position. The Jag in the same function would hold nice and steady, and repeat positions more accurately. We did however have a Jag fail on us at a critical time going into elims.

[Trent B]

2502 used 4 Jags, no failures. They did seem pretty responsive on the low end of the spectrum for our brushes, and they did also allow very slow movement from the drive train which were both nice.

[chris 545]

Victors for us. The Jaguars took up way too much space, and we didn't need the control for our dumper. Didn't need the hooks because we staple the wires down. The max current is 60 but our max breaker is 40. The limiter for keeping the motors from burning out isn't needed because we limit the arm with programming. It is also a bit heavier than victors, which can add up.