Speed Controllers: Which is best?

[mcarobotics]

Our team's robot uses Victors exclusively as our speed controllers because they are smallest and cheaper than Jaguars and Talons.
However, I have seen many teams using Jaguars and Talons a lot instead of Victors. I have seen some people use Spikes a lot as well.
Which type of speed controller works best and why? Which is the best quality/most durable? Which one does your team use the most?
I'm trying to decide if our team should switch next year or stick with Victors.
Thanks!

[CalTran]

For the record, spikes are not "motor controllers" per say...they're relays, and generally used as on/off switches for certain motors (R52 for more information)

Our team used Talons this year, and we are immensely satisfied with the result. The linear response and small footprint is incredible, not to mention how it is an enclosed motor controller so we don't have to worry too much about shavings and dust and whatnot.
As far as using Jaguars, the only reason to continue using them right now would be an inventory of them or if your team is particularly fond of CAN/2CAN.

[midway78224]

For my team we use jags on our practice bot and talons on our competition bot. The first thing we notice was the big difference in the speed of the drivetrain. Then we notice the difference in the flywheel. We ran the same set up on both drivetrain and flywheel just with different speed controllers. On our flywheel with talons we would hit dead center in the 3 pointers but with jags we notice a ft drop in height of shot.

So.... for us we will stick with the talons from now on.

[Ether]

Originally Posted by midway78224

For my team we use jags on our practice bot and talons on our competition bot. The first thing we notice was the big difference in the speed of the drivetrain.

Anyone care to comment on what might be the cause of this?

[Chris is me]

All I can really speak to are Victors - the Victor 888 is everything the Victor 884 was, with linearity. It is just as reliable under extreme conditions. We used 888s on our drive this year and enjoyed the greater low speed controllability and general "smoothness", moreso than other years with the 884. If you're using PWM, they are certainly a worthy choice.

[Racer26]

If I had to guess, my money would be on differences in calibration between the controllers used.

[Alan Anderson]

Originally Posted by midway78224

For my team we use jags on our practice bot and talons on our competition bot. The first thing we notice was the big difference in the speed of the drivetrain.

Originally Posted by Ether

Anyone care to comment on what might be the cause of this?

The cause is almost certainly the fact that Jaguars and Talons use different ranges of control. With the same PWM signal, a motor connected to a Jaguar will run slower than one connected to a Talon. If the same program is used, then either the Talon will reach full output before full power is commanded, or the Jaguar will never reach full output.

The software needs to respect the different speed controller hardware requirements.

[Ether]

Originally Posted by midway78224

For my team we use jags on our practice bot and talons on our competition bot. The first thing we notice was the big difference in the speed of the drivetrain.

Assuming (as I did, perhaps incorrectly) that Team 3997 changed the code to use the proper WPILib driver for each motor controller, and calibrated the motor controllers appropriately, is there any other reason to expect "the big difference in the speed of the drivetrain" they noticed? For example, is there any reason to think that the difference between the Jag and Talon switching designs might interact with a CIM to produce such an effect? Have any other teams noticed a difference (or no difference) in top-end motor speed with Jag vs Talon?

[MrRoboSteve]

Regarding cable retention, Jaguars have a tab below the PWM connector that you should run the cable through. I'd recommend having a tie down nearby for controllers that are purely friction fit for PWM connections, to lower the chance that things wiggle loose. A bit of black electrical tape doesn't hurt either.

There's per-controller tuning in WPILib; don't know whether the same tuning is present for LabVIEW. This means that, for the most accurate response, you want to create speed controller instances that match the controller in use. Having a different controller will function, but with a curve that will seem nonlinear.

Pro tip for WPILib users: declare your speed controllers as SpeedControllers in your header:

	SpeedController *leftMotor;
	SpeedController *rightMotor;

but create instances that match your controllers in use:

	this->leftMotor = new Talon(PWM_SLOT, DRIVE_MOTOR_L_1);
	this->rightMotor = new Talon(PWM_SLOT, DRIVE_MOTOR_R_1);

This makes it easier to switch controllers by making changes only where you construct the instances.

[Jon Stratis]

This is a very difficult question to answer, and there really is no "right" answer. Some pro's and cons of each way we have to control a motor:

- Spike: Good for low-current (less than 20A) motors that just need on/off control. Small footprint and the fact that many teams have a dozen of them laying around from previous year's kit of parts make them popular.

- Victor 884: These have been around forever, and many teams have a ton of them as a result. While they provide variable speed control, the result is the least-linear option available. This has caused many teams to move away from using them for the drive train, or situations that require precise, varied speed control. They've seen a lot of abuse, and have held up well over many years.

- Victor 888: This is brand new this year, has the same footprint as the 884, and provides a much more linear response. Due to their newness, we don't have much experience with them.

- Jaguar: These have been around for a few years. They offer some enhanced features with the use of CAN (encoder/potentiometer inputs, limit switch inputs, feedback from the controller concerning the amount of current draw, etc) that teams have made great use of, although these features can all be had with some extra programming or sensor effort if you're using other controllers. They have the biggest footprint, which isn't the best. Some teams (like mine) haven't had any reliability issues with them over 4 years, while others have complained about them and sworn them off.

- Talon: Also brand new this year, they don't have much run time. They offer a completely enclosed controller, which should help prevent damage from metal shavings. The heat sink on them allows you to run them without fans, although fan use is recommended for high-current situations (like the drive train). They have a footprint similar to the Victors.

We used all Talons this year, and absolutely love them. We only had 1 burn out, and that was due to someone accidentally powering it backwards (fed 12V from a battery into the output terminals), which would kill any of the speed controllers. We have fans on all of them as a precaution against burning any out, although we probably only need them on the drive train. The small footprint allowed us to fit twice as many on our board as we could have with Jaguars, which was a necessity due to space constraints in our design.

[coalhot]

Originally Posted by Jon Stratis

- Talon: Also brand new this year, they don't have much run time. They offer a completely enclosed controller, which should help prevent damage from metal shavings. The heat sink on them allows you to run them without fans, although fan use is recommended for high-current situations (like the drive train). They have a footprint similar to the Victors.

We are using talons for the drivetrain of our robot, and haven't had any issues yet (fingers crossed). We've vacuumed a lot of metal shavings and haven't had any problems at all. No fans either.

[Teamcodeorange]

Originally Posted by mcarobotics

Our team's robot uses Victors exclusively as our speed controllers because they are smallest and cheaper than Jaguars and Talons.
However, I have seen many teams using Jaguars and Talons a lot instead of Victors. I have seen some people use Spikes a lot as well.
Which type of speed controller works best and why? Which is the best quality/most durable? Which one does your team use the most?
I'm trying to decide if our team should switch next year or stick with Victors.
Thanks!

We use Talons and love them. No problems whatsoever. Believe it or not the Talons are even smaller than the Victors.

[mhos1997]

My team uses jaguars for our drive train we vary the other speed controls depending on the motor that we use. We also use the spike specifically for our compressor to control our pneumatics.

[kuraikou]

I know that my team uses talons for our drive train because they are linear and the drive train usually is what other things are getting attached to and so it helps that they are closed instead of susceptible to things getting in them.

[Trent B]

Neutrino used Victor 888's this year, pretty similar to your standard old 884, reliable as long as you don't get metal shavings near them.

Unfortunately we blew a MOSFET on one during the finals at Greater Kansas City (not sure if it was metal shavings or something else), resulting in us calling in a backup to avoid getting DQed.