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Offline Chi-el

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TCB brake servo operation
« on: February 02, 2021, 12:59:30 PM »
Hi All,

I'm currently working my way through designing a high speed tracked vehicle, not so much weaponized, more like a Ripsaw toy version, approx. 1/6.
It will be powered by 2x 8s 56112 Rocket motors with ZTW beast pro sl 200A ESC's.

I know the braking function is included in the TCB by means of a motor break, but I was playing with the idea of doing the braking directly on the drive
shafts by means of 2 servo operated disc brakes.

Would the TCB be able to send the brake signal from reversing the throttle lever directly to the servo's and leave the motors untouched so to say?
Also, I'm eyeing 70 kg PWM servo's that require 500-2500us, would the TCB be able to generate that signal?

EDIT: could these servo's alternatively be operated directly from the receiver?

Thanks!
Michiel

« Last Edit: February 03, 2021, 04:41:21 AM by Chi-el »

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Offline jhamm

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Re: TCB brake servo operation
« Reply #1 on: February 03, 2021, 05:15:26 AM »
Hi,
why so complicated?
With a programmable radio, this can be done by using a mixer.

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Offline Chi-el

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Re: TCB brake servo operation
« Reply #2 on: February 04, 2021, 03:39:32 AM »
Hi,

Thanks, but I'm using a FlySky FS-GT5 with IA10B receiver, so not much to program there I guess.

Would the TCB be able to facilitate any form of controlled brake function?

Regards,
Michiel

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Offline jhamm

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Re: TCB brake servo operation
« Reply #3 on: February 04, 2021, 07:21:04 AM »
I do not think so.
To do this, Luke would have to adapt the programmed mixer and also implement the braking function.
It´s time to think about a Noble NB4.. ;-)

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Offline Chi-el

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Re: TCB brake servo operation
« Reply #4 on: February 04, 2021, 10:22:14 AM »
Or what if I stick two receivers in there, bind them both and one only connects to the TCB and the other one just feeds the braking servo? Or is this just too simple of an idea....

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Offline LukeZ

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Re: TCB brake servo operation
« Reply #5 on: February 04, 2021, 12:45:48 PM »
Hi Michiel, I think that right now this would not be possible. We do have a "Brakes Applied" trigger but it operates in a discrete manner (either yes or no, it is not a variable amount), so presently it can't be assigned directly to a servo output function. And anyway, by the time the "Brakes Applied" trigger occurs the TCB is already braking the motors, and it sounds like you want the brakes to be independent of the throttle.

If you don't mind your servo brakes being manually controlled, you can simply assign them to a free channel, and activate them manually by a switch or slider on your transmitter (I think a pistol grip transmitter is not going to be a good choice for this). In this scenario, yes you can attach the brake servo to the receiver directly, bypassing the TCB completely; or you can use one of the RC Output passthrough functions on the TCB (in the event your receiver doesn't have PWM outputs, only iBus or SBus or whatever).

But even manual control of brakes on a different channel is probably not what you want, you want them to be applied automatically when the throttle is reversed. That I am not sure how to accomplish even with a programmable radio (I guess it would be easy if you only want brakes applied when moving forward, and don't care about brakes in reverse).

Of course anything is possible in firmware but I don't think anyone else will use this feature so I am not motivated to make any changes. Even 1/6 scale Armortek models weighing hundreds of pounds don't use physical brakes (of course they don't move very fast either).
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Offline Chi-el

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Re: TCB brake servo operation
« Reply #6 on: February 04, 2021, 02:07:30 PM »
Hi guys,

Thanks! It is not part of the design at the moment, but there is room to put it in if needed.

It is mainly to ensure a better control when 18 kg is hurtling in the wrong direction at 100km/hr. The drive line is laid out for it though so will use that first.

Anyway, thanks for now. By the time it is up and running I'll simply test it by hooking  a servo up to the receiver and see what it does.

Kind regards,
Michiel