Brushless drive ESC

[Eventorizon]

In my process for designing a machine for live events I was looking at these as a combination:

http://www.hobbyking.com/hobbyking/s...grammable.html

http://www.hobbyking.com/hobbyking/s...tor_730KV.html

Running on 4S, 73mm wheels with two 3:1 belt reductions (9:1 total) it would be able to do just over 10mph.
Looking at the PDF, the ESC is capable of Forwards/Brake/Reverse and Forward/Reverse:

http://www.hobbyking.com/hobbyking/s...7X53414X36.pdf

Unless the ESC can take the large back currents during braking/soft breaking it may have to be run in simple Forward/Reverse.

The alternative would be to get a large diameter outrunner with lots of torque to help compensate for the lower starting torque. But from the vids and other combinations people have done it may not be necessary.

Thoughts?

[knightrous]

I'll just post this link again. Maybe someone is interested in some.
http://vedder.se/2014/01/a-custom-bl...or-controller/

Getting a controller is not the issue, plenty of brushless controllers out there that are proven and reliable in combat robots (the Vedder controller is a big unknown). The big thing we need to do is develop software that will properly for robots and handle a variety of motors (If found some controllers don't like some pole designs in motors ie: H36 motors with a Trackstar controller). BotBitz is working towards hacking the TZ85A to work as a dual purposes controller in both it's current Brushed mode that we sell, but also a Brushless mode. The problem is we need a good amount of time to develop the code, test it with a large range of motors and conditions before we could even consider selling it. At the current moment, I find the Turnigy Trackstar 6S 150A V6 controllers to best off the shelf solution, they are fully programmable, zero delay, have a wide range of voltage (2-6S) which suits most robots and they also have sensor ports (Just need some good sensored outrunners ). So while this controller is readily available, it kind of makes the job of hacking the 85A into a dual mode controller a reinvention of the wheel and therefore a slow progressing project.

I still keep reading that sensorless outrunners won't work.

It's not a case of them not working, it's a case of the conditions they are applied to they don't always work correctly. We have plenty of videos (as posted previously) with robots driving around with outrunners with sensorless controllers, but if you put the robot in a standing start stall condition with full weight and traction, they don't work (Check my video where the weight is distributed level). If your robot gets pushed into a corner and the opponent pins you, the sensorless setups rarely startup and just sit their cogging (as seen in my video) until they can make the first commutation. This is where the sensored controllers really shine, even when stalled, they can begin commutation instantly. This is one reason why I'm trying the bigger NTM 42 series motors is to get better start up torque, not to get 500+ watts of power into the drive.

Charles Guan (e0Designs/etotheiplusone) has done some epic builds with electric scooters and go karts using big outrunner brushless motors and ended up shifting to external to get reliable standing start performance in go karts, where 300lbs of weight taking off from a stand still with wheel spin is the game...



EDIT: Forgot to comment against Nick's post.
I already have a set of those motors for testing, however this is what I dont like about them:
- Max of 4S means they are only suited to low voltage robots or you have to build split powered robots with two batteries.
- Weight, they are 300+g each, which is nearly double the weight of a comparative outrunner.
- Cooling, they are fully enclosed and rely purely on the small heat sink fins. You could add fans etc etc to them, but this is more weight, space, complexity and it's probably not as good as the cooling an outrunner provides to itself.
- Size, they are pretty long motors, much longer then the outrunners and even Dewalts.

[leorcc]

Beefy motor for that ESC. I use that ESC for my truggy and it performs well but it is designed for 1/8th scale applications. The settings are adjustable for your needs, the programmer can minimize the forward/reverse delay to as close to 0 as you can get it. The motor itself should have no problem starting up with your reduction ratio.

[Mouldy]

Nick what ratio banebots did you run this year? Id be Kinda tempted if i could find a motor to mate onto my banebot 16:1's to run my 98mm wheels with similar performance to what im currently getting

[overkill]

Nick what ratio banebots did you run this year? Id be Kinda tempted if i could find a motor to mate onto my banebot 16:1's to run my 98mm wheels with similar performance to what im currently getting

I am using 26:1 gearboxes and the pinion has a 1/8" bore. The set-up wouldn't have anywhere near the torque of your motors (775's, I guessing?).

For your 16:1 gearboxes, I would use a pinion with a 5mm bore and either one of the NTM outrunners like Aaron @ BotBitz is testing, or a larger sensored inrunner like this:



http://www.hobbyking.com/hobbyking/s...or_1900KV.html

If you want to wait a week or 3, I have a pair of those on the way for testing. You might want a bit different KV motor depending on your battery voltage and the speed you want - luckily there is quite a range to choose from. Will the 70mm can length be a problem for you?

[daveimi]

Yeah I meant brushless ESC lol. Was wondering if TZ85's are already brushless and there are loads of them kicking about to begin with someone could give them a go?

[overkill]

Yeah I meant brushless ESC lol. Was wondering if TZ85's are already brushless and there are loads of them kicking about to begin with someone could give them a go?

Unfortunately, the TZ85 in it's original form is not reversible - you need a car brushless ESC for that.

[typhoon_driver]

Well I'm going to watch this one from the sidelines with interest.

[Mouldy]

No that would be ok- look forward to seeing your results!

[overkill]

Hi Aaron,

Those HK motors seemed the closest to what I wanted and a logical step up from the 540 sized motors in Mr Mangle. I don't think they will get too hot if geared right - the 540 motors got pretty hot on the bench test but not so much in the arena. The other plus with the sealed inrunners is that the dirt stays on the outside.

Its obvious that both types of motors have their strong points; what we really need is for you and Steve to make an external sensor board for the NTM 35 or 42 series motors . That would tip the advantage solidly over to outrunners.