[FRC Blog] 2017 Motor (and Servo?) Controllers and MXP

[Greg Needel]

Originally Posted by bobbysq

The REV servo controller seems interesting, although I can't seem to find it on REV's site. If it's just a single thing for a servo, it might not be worth it, (and one could probably inject more power into the PWM wires by splicing) but if it has multiple ports, it could be cool to have if you had a lot of servos.

Sorry we were late making our product page public. You can learn more about it here http://www.revrobotics.com/rev-11-1144/

Originally Posted by Lil' Lavery

Curious to see what the 2017 Servo rules will look like. Could kill off the small niches in which the NeveRest 60 had some FRC applicability.

We don't know what the rules will end up being but this is designed to allow much larger servos on robots, so I would hope the rules are open enough to allow them. In addition to our Smart robot servo, there are plenty of large scale servos available in the open market.

The real added benefits of this come from cost per degree of freedom, since you don't need a separate motor controller for your servos you can save at-least $45 per actuation over a motor by just removing that requirement. We will all learn in January what FIRST will allow this year.

[pilleya]

Originally Posted by SRM Product Page

The Servo Power Module is a 6V 90W power injector that enables the use of high-power RC servos in applications where a robot controller cannot directly provide adequate power.

There are some really powerful Brushless Servos with steel/titanium gears out in the RC marketplace so this sounds like an awesome addition to the electrical components that FRC teams have available to them.

Some of the High-End Brushless Servo's can be more than $100 so it seems like there could be disparity between what the Servos teams have available to them. But we will have to wait until we see the specific rules.

[Andrew Schreiber]

Anyone know of any extra documentation on what the SD540C gives you?

[Rich Anderson]

Originally Posted by Greg Needel

Sorry we were late making our product page public. You can learn more about it here http://www.revrobotics.com/rev-11-1144/



We don't know what the rules will end up being but this is designed to allow much larger servos on robots, so I would hope the rules are open enough to allow them. In addition to our Smart robot servo, there are plenty of large scale servos available in the open market.

The real added benefits of this come from cost per degree of freedom, since you don't need a separate motor controller for your servos you can save at-least $45 per actuation over a motor by just removing that requirement. We will all learn in January what FIRST will allow this year.

I am working on a prototype turret driven by a pixy cam, and am worried about the servo load on the pixy. Would the motor controller be the answer for an arduino server output too? I am thinking of using a parallel 12v to 5v power supply similar to the LED light hookup on the RioDuino. The servo power supply sounds neat if the game calls for servos this year (I would like to use the Smart servos, which we already have in our inventory).

[EmileH]

How come Analog Devices' ADIS16448 isn't listed as an approved device on the MXP, even though it is available in FIRST Choice?

[Mark McLeod]

Originally Posted by EmileH

How come Analog Devices' ADIS16448 isn't listed as an approved device on the MXP, even though it is available in FIRST Choice?

FIRST gave us a list of legal MXP all-in-one active boards, not the individual devices we plug into the roboRIO expansion port or the 3rd party MXP all-in-one active boards.
What we plug into them is up to us.

[EmileH]

Originally Posted by Mark McLeod

FIRST gave us a list of legal MXP's, not the devices we plug into MXPs.
What we plug into them is up to us.

Ah, now I understand. Thank you.

[Bkeeneykid]

Another thing to consider is that this is only the approved list of active devices. Under R69 from last year, this is the definition of a active device:

An ACTIVE DEVICE is any device capable of dynamically controlling and/or converting a source of electrical energy by the application of external electrical stimulus.

The ADIS doesn't control and deliver a source of electrical energy, so it wouldn't need to be on this list.

[Poppeseed]

Originally Posted by EmileH

How come Analog Devices' ADIS16448 isn't listed as an approved device on the MXP, even though it is available in FIRST Choice?

This list is only for active devices. My understanding from the 2016 rules (R68/R69) is that it's only considered active if it generates motion from the output pins. Something like the ADIS16448 is a sensor, and therefore flals under their passive device label.

You can read more from their blog in 2014 if you like, but rules may have changed since then.

[Joe Ross]

Based on the SD540C Library documentation (http://www.mindsensors.com/reference/FRC/html/Java/) it looks like the SD540C is just a CAN enabled dumb speed controller, rather then a Talon SRX competitor.

[bobbysq]

It appears to have a few "smart" features, like getting the limit switch and changing brake/coast while driving. Overall, I think I'd still pick the SPARK over this at the moment, seeing how it offers the same limit switch stop feature (it's not hard to code in anyway) and costs $5 less with the option of buying through Amazon Prime.

However, something to note is that the manual mentions encoder inputs and currently says:

Closed loop Control feature is not available in firmware at this time.
However, you can upgrade firmware of your device to use those
features as soon as the firmware is available.

If they can add this feature soon (and before Kickoff soon, people won't design for features they don't have) and it works well, then the Talon SRX may be seeing its last season of being the dominant motor controller.

[marshall]

Originally Posted by bobbysq

If they can add this feature soon (and before Kickoff soon, people won't design for features they don't have) and it works well, then the Talon SRX may be seeing its last season of being the dominant motor controller.

If.

[bobbysq]

Originally Posted by Rich Anderson

I am working on a prototype turret driven by a pixy cam, and am worried about the servo load on the pixy. Would the motor controller be the answer for an arduino server output too? I am thinking of using a parallel 12v to 5v power supply similar to the LED light hookup on the RioDuino. The servo power supply sounds neat if the game calls for servos this year (I would like to use the Smart servos, which we already have in our inventory).

It should be able to act as an output for any device. If I were to guess, it outputs +6V on the center rail and GND and signal are simply passed through.

Also, remember that in competition servos need to be controlled by the RoboRIO.