Spare ESC for use at the champs?

[Ellis]

Hi guys. I don't like having to do this, but it's worth finding out what our options are.

We're running an Electronize 30a on our lifter at the moment, and electrically it's fine, but the relay-based control is really screwy. It's almost impossible to get the forks to sit flat on the floor on first try. We had hoped to get the thing working like a servo before the time, but it looks unlikely - we have to leave here in 10 days.

My question is whether anyone has a suitable ESC going spare that we may be able to use at the champs. Preferably a tz85, as we know they're up to it and I imagine the breaking function will help this over-shooting issue with the forks. Open to suggestions, though. The motor is rated at around 65a at absolute stall, if that helps you judge.

Obviously we recognise it would be a risk on your part putting your ESC into combat, so we'd work out a deal (I don't expect this for nothing, if anyone even has something suitable) and if anything in the slightest goes wrong with the ESC whilst it's in our hands, we'll cover the costs.

Thanks. Again, just investigating our options.

[grant_ploughbot]

Are you using limit switches to stop at the top and bottom of the stroke? Or even just at the bottom?
I am trying to make up a small pic based limit stops for predator and my axe at the moment that can go straight inline with the RX/ESC so that you can use botbitz controller's etc without external relays and still get limit's. I might have one made up spare for the champs if you wanted to try it and see if it helps.

[Ellis]

I'm open to try any setup. The problem isn't the travel limits though, as the weapon works like Sewer Snake's, and it goes underneath the robot as well as lifts up like typical forks (a lá Panic Attack). The problem is that the fork tips flat on the floor isn't an end of travel point (so it can't be limit switched or we'll effectively lose half of our weapon), it's right in the middle of the weapon's stroke.

Hard to explain...

I need to be able to stop the weapon when it's flat on the floor more easily, without it going past the point and lifting our wheels up or staying up a bit so it can't get underneath stuff.

I had hoped to make it work like a servo, so that TDC is the forks with 0 clearence, and it automatically reverts to that position after I use it, but having it work like a massive servo in ten days is looking doubtful.

You can see the problem clearly in this video:

[Anttazz]

Is there some way that you can set that as a default position? As in, when you release the stick it returns to a preset place.

[Ellis]

Is there some way that you can set that as a default position? As in, when you release the stick it returns to a preset place.

Yes, servo control.

That would be the perfect situation, but even if someone has the right electrical side, it can't be plug-and-play, because you need to setup a potentiometer, which isn't all that straightforward in our machine unfortunately.

[typhoon_driver]

Well if you cover the cost I could reprogram a turnigy 85a for you and hand it to you at the champs.

[PJ-27]

Sewer Snake just uses it's and the forks weight to get them flat on the floor, he just slams them down and drives. No limit switches, no torque control.

I guess because of your lesser weight you aren't getting that?

What voltage are you running 5S?

[Ellis]

Yeah, the weight of his forks brings them down, but we're using a higher reduction and in proportion less weight in the forks than he is, so it has to be brought down under power.

And yes, 5s.

Gary we may well take you up on that, I'll PM you if we do. Thanks.

[Eventorizon]

We have 2 hacked TZ85A's that are spares for both Conker and Binky if you get desperate.

I also have two constant rotation potentiometers that I bought for my final year project but are now redundant. Designed for high stress applications it would be ideal for getting your forks working as a servo.

[Ellis]

We have 2 hacked TZ85A's that are spares for both Conker and Binky if you get desperate.

I also have two constant rotation potentiometers that I bought for my final year project but are now redundant. Designed for high stress applications it would be ideal for getting your forks working as a servo.

Interesting! How would that work in our setup? Does it go between the motor and ESC or the ESC and Rx?