Playing With Fusion 2020 FRC New Product Release - Venom Motor, CAN

Playing With Fusion is excited to announce our 2020 FRC new product linup! We have begun manufacturing processes and expect to begin shipping motors in the first week of December.

Venom Release Video

The CIM is dead… Long live Venom!

It’s hard to kill a CIM, so instead, we’ve given it some long-needed upgrades! This include front and rear ball bearings for increased efficiency and an integrated smart controller and on-board encoder. No more external controllers and complicated wiring to get the best controllability for your drivetrain! All of this makes motor wiring, programming, and sensing easier than ever. The feature set is far too extensive to describe in a short announcement, so head over to the Venom product page for all of the details.

You CAN do it!

CANdaisy 5-Link Traditional daisy-chain connector board

We know that a single twisted-pair CAN connection is going to blow some minds, so we’re also releasing a number of CAN interface boards to make your wiring life easier.

CANstar 2-Drop short drop network board

CANstar 4-Drop short drop network board

CANterm 120ohm W2B CAN terminator board

While it’s not technically NEW, we introduced our 4m ToF CAN module a little late last year, so we’re going to count it!

Thanks, and have a great day!
-Justin
Owner, Playing With Fusion, Inc

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Can we place pre-orders? If yes, when can we do that? It looks like a real saver for wiring!

Pre-orders are live now, we’re expecting to begin shipping the first week of December.

Here’s the link to all of the products just announced: https://www.playingwithfusion.com/static/frc.php

Thanks!
-Justin

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Have you done any tests to see the impact of the changes you’ve made from the original CIM on the motor’s performance? I’d be interested in seeing if using bearings instead of bushings and better cooling properties makes the motor’s max. power decrease less over time. That would be the main reason I see to use the Venom over a traditional CIM.

Also, can you explain a bit more about the thermal protection.

Onboard thermal management protects the CIM and integrated controller from excessive duty cycles at high load.

What exactly are the criteria that enable the protection? What does protection entail? What are the criteria for protection to end? The last thing I want at the end of a hard-fought match as I’m trying to score my last game piece to win the match is for my motors to unexpectedly shut themselves off.

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This seems promising, especially for modern FRC applications that need High low-end torque. I don’t know if you are allowed to answer, but have you worked with FIRST to ensure that this will be a legal motor and motor controller for the 2020 season? Also, are you able to provide any empirical testing data?

https://www.chiefdelphi.com/t/frc-blog-2020-motors-controllers-and-some-other-robot-rules/365126/13

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*Facepalm* should have checked that before asking lmao. Welp, MAR teams always have eachother’s backs. Thanks!

Running at lower temperatures is the only way to avoid killing bushings, bearings, and magnets, so at a high level, everything about this design works to improve CIMs longevity.

With regards to thermal protection strategy, Venom monitors motor current and back plate temperature. If the average motor current exceeds 40A the control will slowly limit its max output. The motor will not suddenly stop due to excessive current. Similarly, the motor will begin to limit max power output if the end plate temperature exceeds 90C, with a linear ramp to 0% at 110C. The motor automatically restores power as cooler temperatures are realized. So, there’s the theory and control strategy - which we’ve fully tested to protect the electronics package. In practice, the only way you will hit 90C is if you run 30A continuously for several minutes - not something you’d likely see in a match, but plausible in some practice situations (heavy arm controls with back-to-back battery runs, for example).

Thanks!
Justin

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Welcome to the FRC motors and controllers market!

I presume you’re participating in the beta program. For the mere mortals among us though, do you have API docs and/or libraries compatible with the 2019 roboRIO image to play around with?

Does the thermal protection kick in if the motor is drawing over 40A average but still cool? Or if the motor backplate is above 90C but drawing little current? In other words, does the thermal protection need either or both cases to be true to enable?

If I only need my motor to have a 5 hour lifespan but I want to push its power limits, can I disable this thermal protection? CIM motors can get pretty hot in the drivetrain, holding an un-counterbalanced arm, or many other applications where it draws large currents for long times. Obviously good designs should strive to keep the motors cool, but this is FRC and sometimes stalling your motor all match is easier than designing properly.

Also, what does the spec “Iout Max (A): 60” mean? Is that saying that the controller imposes an artificial 60A current limit on the motor?

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In other words, does the protection scheme consist of:

  1. thermal limiting
  2. current limitng
  3. both thermal limiting and current limiting

#3 - Both

The over current and over temperature derate power limits are calculated separately, then multiplied together. We keep saying power limits, but internally is just a duty cycle limit to the H-bridge driving the motor. So our true duty cycle becomes:
DutyCycle = DutyCycleFromUser * CurrentLimitMaxDutyCycle * TemperatureLimitMaxDutyCycle

where CurrentLimitMaxDutyCycle and TemperatureLimitMaxDutyCycle are normally 100% when the motor is cool and the current is less than 40 A.

The thermal and current limits are separate. If either are exceeded the motor will begin to derate.

Venom will certainly tolerate stalling the CIM at full load, but how long it can stay there is a function of temperature. If we allowed heat to build up in the CIM unchecked we would risk damaging the electronics in the controller. 90C is plenty hot. At that temperature you’d start to see the bar code label on the CIM start to blister off. If you’re not used to seeing that I’d expect Venom do do just fine in your application.

The 60A Iout Max spec on our website refers to the limit in the controller software. Venom begins to limit max dutycycle at 40A average current. The maximum duty cycle decreases to 0% and 60A average load. Since we’re looking at average current, Venom will tolerate current spikes above 60A for a short period. The higher the current the faster the motor will start to derate.

One of out design goals was to never cut power suddenly. The last thing we want is for Venom to cut out in the last 10 seconds of a match. The proportional derates allow the motor to continue operating - although at reduced capacity.

As Justin said earlier, matches don’t run long enough for thermal limits to be an issue. This protection is there for practice when you swapping batteries faster than thing can cool back down.

We will expect to release the API November 11th. I’ll see what it takes to get a 2019 library released in time for the December ship date

Argos 1756 has been using the Venom motor all summer during are driver practice. We would usually run them for 2 hours straight with only stopping for battery changes and had no heat issues or performance decrease. We have put around 20 hours of hard driving on are 4 motors. When I say hard I really mean it. We told are students they could do what ever they wanted with the robot and wow did they do that. I do not think I have seen a robot hit another robot so hard or push into a wall for so long. We have a nice bent frame rail and some burn marks on are field to show from it but man did they have fun. Through out the testing we had 0 software issues, heat, or performance decrease problems. Over all they have been just what you would expect from a cim but way smarter and much easier to install.

I think are favorite part about this motor is that it is built of the reliability of the cim and we know with the extra smarts we can just bolt it in and forget about it. Also we do not have to worry about burning it out and having to drop another $120 on a new system.

If you have any question about them fell free to send me a message

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What current limits did you set in your software whilst running the robots?

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I am not are lead programmer however i do not believe we used any current limit.

Is there a cad model of the venom available?

We intentionally did not set any current limits on the robot using Venoms. The motors got toasty after a couple hours of run time, but we never noticed any performance degradation.

Other than an integrated motor drive, does the Venom make any improvement to the CIM? In particular the same no load current and no load speed apply?