Dual motors running tracks

[Jonathon Gillham 4606]

How do people running tank tracks where they move independently so do the steering as well as fwd/rev? Is it easiest just to run a separate ESC and motor for each track or is there something clever you can do? I assume the dual motor ESC (like the HW 860) run the motors the same so couldn't do the steering?

[Lee76 638]

I just had a look out of idle curiosity at the manual downloads - https://www.tamiya.com/english/rc/manuals.htm

There's instructions for all the tamiya tanks, there’s tank specific speed controllers. 

There are instructions for this here:- http://www.tamiya.com/english/robocon/robo_parts/dmd_t03/dmd_t03.htm

Also loads of videos when you search for the DMD speed controller.

What are you making/modifying? Anything special?

[Backlash 481]

My Tamiya tank has a Tamiya DMD control unit that handles both the steering and throttle from a standard 2channel radio.. (Its like 2 x ESC's in a box) 

I suppose that you could do something similar with 2 individual ESC's and some programming on a computer radio..

[Jonathon Gillham 4606]

9 minutes ago, Lee76 said:

I just had a look out of idle curiosity at the manual downloads - https://www.tamiya.com/english/rc/manuals.htm

There's instructions for all the tamiya tanks, there’s tank specific speed controllers. 

There are instructions for this here:- http://www.tamiya.com/english/robocon/robo_parts/dmd_t03/dmd_t03.htm

Also loads of videos when you search for the DMD speed controller.

What are you making/modifying? Anything special?

 

Thanks I had never heard of these, it makes sense that they would exist though.

Just a cheap tank chassis which comes with dual motors that my son will make a body for so it should look a bit like a tank. Banggood have them for not much, like $20 - $35 depending on size. So it doesn'tneed anything flash, just so it drives.

7 minutes ago, Backlash said:

I suppose that you could do something similar with 2 individual ESC's and some programming on a computer radio..

I'm hoping this will work since I saw the price of that DMD controller! I will be getting a stick programmable controller soon so it should be possible to make it work, probably...maybe...

 

[Juggular 4964]

In that case, cheap 15A ESCs would work just fine. Most use 380 or smaller motors anyway.   

I once looked into 2ch stick transmitter to see if I can turn the steering one vertically (for a similar project).  There was a problem; like trim tab couldn't be turned or some such thing if I remember correctly.  With 4ch transmitter, this won't be a problem.  Oh, I did buy a 4ch radio, thinking that I'll need it for a tank (another forgotten project!).  I never got to use that, because Henglong tanks came with their own transmitters.  

 

[waterbok 1282]

Pfff, you could get that running, but you would need a remote with mixer function or  a 4channel and use left and right stick for tracks.

I think i have seen combined esc/receiver on banggood that could do two motors but not entirely sure.

If you any good with electronics and remotes, you should be able to get it running with a flysky GT3B with modded software and a 6ch receiver and have spare channels left for other things.

 

 

[Ray_ve 1043]

On my leopard tank, I used 2 ESCs, 1 per motor.

The ESCs were connected to the receiver via a model plane 'V tail' mixer. This type of mixer mixes up-down and left-right steering into the appropriate movements for plane with a V-shaped type tail, that has the rudder and elevation combined into 2 moving planes that need to move in a combined motion.

This  specific mix also matches the movement you want on tank tracks, so the transmitter can use a forward-backward stick and a left-right stick, just like a car. And no special settings are needed on the transmitter.

 

edit: The tamiya tank was modified so it runs 2 motors, instead of the 1 motor and clutch.

[Jonathon Gillham 4606]

Thid is sounding better and better. I was just thinking using sticks with both forward and rev, but that mixing function sounds really cool. I need to order the chassis today in the hope it arrives in time for xmas. If you get over the value for a tracking number it tends to be a bit quicker

[Juggular 4964]

5 hours ago, waterbok said:

If you any good with electronics and remotes, you should be able to get it running with a flysky GT3B with modded software and a 6ch receiver and have spare channels left for other things.

1

This is not the first time you mention the software mod. 

Me being a very impressionable youth (okay, I'm not that young), I got around to look at it.  I have to say I'm happy that I did (thank you).  But I don't think there is any channel mixing function (unless I missed that?).   

Just like Ray-ve said, for airplanes, channel mixing is often used.  Even the cheap Flysky FS-i6 has V-tail preset.  It would be nice if other channels can be mixed.  Like flapperons (ailerons on both side wings move in the opposite direction when banking, but come down together to function as flaps while still moving independently).  You can mix throttle and flaps; when in full throttle, flaps come down at 40 degrees, but when landing it at 40% throttle, the flaps would be 20 degrees so it wouldn't float up a light plane too steep.  If flaps make the nose go down, or up, elevator can be tied to flaps to change the attitude too.  Channel mixing was often available to RC Air folks.  

For us the RC surface folks, I've been thinking how useful if we could have the "responsive steering" function.  If I can limit the steering angle as the speed goes up, there would be a less chance to flip a precious vintage car.  20% throttle could limit the steering 10%, and 100% throttle could limit the steering 50%, etc.  

Futaba 6L seems to have pre-set mixers with physical switches in the back.  In this radio, elevon mix might get you what you want?  Because aileron and elevators are controlled by the right stick in a mode 2 radio.  (obviously, you don't need to mix anything if you plan to use both sticks)  

 

 

[Jonathon Gillham 4606]

This is the chassis I have bought, its very much a toy one.

https://m.banggood.com/3V-9V-DIY-Shock-Absorbed-Smart-Robot-Tank-Chassis-Car-Kit-With-260-Motor-For-Arduino-SCM-p-1155264.html?rmmds=search

Hes only 5 and will make a most likely cardboard/paper mache body for it. 

It has little motors fitted already but no idea about controls. No problem though as cheaped brushec ESC are $7 each so it will be easy enough to work out.

Interesting stuff about the V tails.

@Juggular I think the Futaba 4PV has that function for exactly that purpose - slowing steering rate as the car speeds up.

[waterbok 1282]

13 hours ago, Juggular said:

Me being a very impressionable youth (okay, I'm not that young), I got around to look at it.  I have to say I'm happy that I did (thank you).  But I don't think there is any channel mixing function (unless I missed that?).   

Its called DIG funktion if i am correct.

https://overkillrc.reamaze.com/kb/flysky/01-introduction

13 hours ago, Juggular said:

For us the RC surface folks, I've been thinking how useful if we could have the "responsive steering" function.  If I can limit the steering angle as the speed goes up, there would be a less chance to flip a precious vintage car.  20% throttle could limit the steering 10%, and 100% throttle could limit the steering 50%, etc.  

And that would be the dual rate or exponential  function

borrowed this bit from overkillrc

Exponentials are a very useful parameter; their main goal is to provide better control of the channel where it is needed. Lets look at steering in a go fast rc vehicle for example. Generally, at high speeds only minor adjustments to the steering is needed to stay on course...but if the adjustment is too jerky or isn't precise enough the end result could be detrimental. This is where expo comes into play, what expo does is it turns the linear steering curve into an exponential steering curve. So the curve can be flatter towards the center of the channel and really steep towards the end of the channel. The outcome makes it so the minor steering adjustments towards the center are accurate and precise but it'll go to full lock much faster and not allow for very accurate sharp turning.

 

[Jonathon Gillham 4606]

Ok so all the bits are coming together nicely for this.  Except the crimpers, they are on their way, so fitting the plugs to the motor wires to plug the ESC in will be difficult.

So far I have the following:

Chassis with 2 little motors, 1 for each track.

Servo for the turret rotation (will either buy a stepper motor or try to convert the servo into a stepper motor for full rotation, 120deg is enough for now)

Servo for gun elevation (just cos I could).  Thats not actually here yet but should be very soon.

2 ESC, 1 for each motor.

Flysky FS-i6 and the 6 channel rx

I've plugged everything in (held the motor wires into the ESC plugs, it worked...) and everything works as expected.  The only thing I haven't done is "plugged in" both ESC at the same time as I don't know what I need to do about batteries.  So here are some questions

Do I make up a Y lead and plug 1 battery into both ESC or use a separate battery for each ESC?

If I use a separate battery for each, how does that affect the Rx since that means it will have 2 power sources?  Or do I use the battery slot on the Rx and then batteries for the ESC?

I have the option of those 4x AA battery holders which I seem to have a bunch of, or my rx pack from my bitro buggy.  I could buy a second rx pack as that would be useful as well, but since I have the AA battery holders I would prefer to use them as I don't have to worry about storage charge etc.  Will 4 AA's handle current draw from 2 little ESC and motors and servos or will there be brownouts?

 

I have a bunch of balsa wood leftover from the yacht build, I'm tempted to make a tank for me as well but this is really his project, at least the building part is, I'm just making it work.  Or not!

 

[Busdriver 6209]

Might be a bit late for this but try action electronics. https://action-electronics.co.uk/home.html Primarily a boat electronics (model) but they have loads of gizmos that would help. Boat builders are really into multiple motors and steering with them

[Jonathon Gillham 4606]

6 hours ago, Busdriver said:

Might be a bit late for this but try action electronics. https://action-electronics.co.uk/home.html Primarily a boat electronics (model) but they have loads of gizmos that would help. Boat builders are really into multiple motors and steering with them

Thanks, some interesting stuff available...especially the sound stuff

The tank works, it was surprisingly easy. It needs painting and an FPV setup is on its way too, just for fun