Assistance with Cube Orange and transmitter issues

Hardware Other Hardware
1

Hello everyone!

This is my first post and hope that I will not get bashed for posting in the wrong category :).

First and foremost, I am live in Ukraine and parts are very hard to come by here which is the reason I have some cheaper hardware.

That said, my step-son and I are building a rover tank. Yes, ironic due to the current war here but we must do something to keep our mind off of the situation or worry when the next missisle will strike.

We have printed a 3D rover tank and built. Now we are assembling it and running into issues with control.

We currently have the following hardware:

Cube Orange
Here 3 GPS module
Fly Sky GS-GT5
Fly Sky BS6 Receiver
2 Leopard Brushless 13.0R 3000KV
2 Leopard Burshless ESC

Our goal is to build a tank skid steer rover that we can control both with the fly sky GT5 controller as well as mission planner, which I will connect to a raspberry pi and cellular USB modem when I can find the hardware.

One thing is becoming very obvious, it seems GT5 controller is not capable of controlling a skid steer model due to its inability to reassign or mix channels, unless I am missing something. I thought about connecting the receiver to the cube orange and controlling each motor but now it seems I am not able to connect this receive to the cube orange.

I do have access to purchasing a new receive that seems to be compatiable with Ardupilot, which is the FlySky FS-IA6B as it supports PPM, but from my little knowledge it seems that this controller does not support PPM, which I do not think it would work.

I do not know what to do at this point. As I said before, parts are very hard to find due to the war.

One company that I am able to buy a few parts from is: modelistam.com.ua, which they are quickly running out.

Can anyone shed some light on what we can do to control our model?

I hope I have provided enough details for you to assist.

Thank you in advance.

2

Hi,

as you already noticed, you will need a receiver with PPM or better a receiver that supports Sbus or another supported serial protocol. There is also the possibility to use a PPM encoder, but only if the integrated gyro in the receiver can be deactivated.
A pistol grip transmitter is not ideal, but the transmitter does not need any mixing capabilities. Skidsteer mixing is done by the flightcontroller.
I do not know the design of your rover, but those motors will need a reduction gear, at least 10:1, better more. Direct drive will not work with a 3000kV inrunner.

3

That Reciever is individual PWM output , Cube Orange requires PPM, Sbus, Ibus, couple others. You could use a PWM to Sbus converter. PPM is fine so that other Flysky RC system will work. You will find plenty of posts about use of that Tx/Rx on Ardupilot platforms.

You would be better off with brushed gearmotors.

4

Thank you for the reply, Sebastian.

I agree that a pistol grip is not ideal, but unfortuntaly it is all we can come by for now. We are actively looking for other transmitters but none are available and we are not able to import any at this time.

We are using a 4:1 gear reduction.

If I was to purchase a new receiver that supports PPM such as the FlySky FS-IA6B, I am concerned that my transmitter would not work with the receiver as it does not have PPM options to enable on the menu.

Thoughts?

5

Thank you, Dave.

Do you have a reccomendation on a decent PWM to Sbus converter?

And I agree on the motors, we just bought the last ones we could find. Hopefully we will have more options, soon.

6

I did find this PWM to Sbus converter, seems to be the only one I can find in the country.

Screenshot 2022-06-12 at 23.02.02
Screenshot 2022-06-12 at 23.02.021022×700 46.5 KB

This this would be a good option?

7

I would not assume that any other Rx, even a Flysky one, would work with that Tx and even if it does you are still stuck with PWM because that protocol is configured on the Tx and sent to the Rx on bind. The FlySky FS-IA6 might work as it’s the same protocol or it might not.

But yes that converter and others like it could work.

8

A 4:1 reduction still results in 750kV at the wheel. With a 2S lipo you will get around 6000rpm at the wheel unloaded. While a high topspeed is not a problem in itself, because you can always drive slower, the problem will be to get the rover to start smoothly. Sensorless brushless motors have a big problem starting to turn when under load. With a fast RC car, the ESC uses a “jump start” to get the motor turning. But even a fast RC car will have a much higher gear reduction “motor to wheel”, than 4:1. A rover should be able to start smoothly and drive at a very slow speed.
If your 4:1 reduction is 3d printed, try to add another reduction stage or two.