Twin motor and twin steering servo set-up

[BlackSeaRC]

I have an application where I have two motors and two steering servos. I would like to use a pistol grip and wheel style transmitter to operate the vehicle as follows:

Mode 1: Trigger operates motor 1 only and wheel operates steering servo 1 only.

I want to flick a 2-position switch (or press a button) to change between Mode 1 and Mode 2.

Mode 2: Trigger operates motor 2 only and wheel operates steering servo 2 only. BUT, I also want motor 2 to rotate in the same direction for forward AND reverse.

I assume that I would need 2 ESC's connected to a receiver. Is it possible to set-up this functionality using a transmitter with mixing?

 

[ferp420]

you had me untill the part were you sead motor turning the same direction weather forward or reverse

must see pics to understand

 

[HumboldtEF]

Yeah that detail didnt make sense to me either. Why would you need reverse at all if you just want it to spin in the forward direction?

Mixing may be able to acheive most of what you mentioned aside from reverse not being reverse. The programming may be failry involved though. Its likely to be similar to setting up an MOA with 2 ESCs and motors.

 

[ferp420]

is this for a tracked vehicle ?

 

[BlackSeaRC]

The first motor and steering servo is to drive and steer a wheeled off-road vehicle. The second motor is for a water jet drive (the vehicle is amphibious). The second steering servo is to steer the jet nozzle. An additional servo will operate the waterjet reverse bucket.

 

[OSRC]

I'm not aware of any radio where you can alternate uses of the throttle (ch2). Possibly on an airplane radio, but not on a typical surface radio.

Most likely your second motor will have to be on separate channel so you can configure it to your liking.

 

[ferp420]

ooohh ok I C off the top of my head i would say you need a radio that can switch profiles and has channel mapping
say like 1 setting or on the radio link would be model 1 use that for on road and set model 2 to water use

on model 1 setting use sterring and throtle like normal channel 1 steering and channel 2 throtle for model 2 you would need to map out the channels tell the radio to use channels 3,4,5 for steering throtle and to activate the reverse
switching between models is pretty easy but not something i know how to set up for use on the fly it takes a few buttons and some scroling but not hard to do at all

there might be other ways but thats what poped in to my head right off the bat

 

[ferp420]

another thought would be set it up like a motor on axle rig
use 4 wheel steer modes thats pretty easy yo do and the motors could be on the dig settings
4 wheel steer usualy lets you control ether front steer or rear steer or both ether turning both sets of wheels yhe same way or in your case would be the opposite way
dig would alow for front dig that only turns the front motor or rear dig that turns the rear motor or jet pump in your case or both and usualy and thaing in between
that would be nice if you could turn the tires slower than the jet pump or faster lol

the only issue would be the jet pump turning in reverse but that could be locked out on the esc side and not on the radio programing side
you could aso then shift on the fly with 1 button for 4ws and 1 button for dig and a seperate channel for the reverse bucket

 

[ferp420]

but now we want some pics you cant come in here talking about a cool project like a amphibious off road vehicle and not provide pics of what you have going on
if your still in the planning stage thats cool but dont forget to give us the crack after you start building
cause you know with out pics its just a pipe dream

 

[Gula]

The first motor and steering servo is to drive and steer a wheeled off-road vehicle. The second motor is for a water jet drive (the vehicle is amphibious). The second steering servo is to steer the jet nozzle. An additional servo will operate the waterjet reverse bucket.

Haha, wouldnt be a schwimmwagen like this would it? I think ill be watching this thread to see how ill have to figure out a way to controll mine.

 

[Gula]

I may just do it this way:
Steering (ch1) on the "axles" is mixed with the(ch3) "rudder" Permanently. Throttle is standard (ch2) (ch4) will be a servo that disconnects power via micro switch, etc between each of the two motors. Like an old school clodbuster dig, where a switch is flipped to power either the "boat" or the "car" motor. Only one motor gets propulsion power.

 

[BlackSeaRC]

No, it's not a Schwimmwagen, it is a custom build project and I'm just in the early stages of establishing what is possible. I know what I want to achieve as the end result but there is a lot of equipment to fit in a small space. The challenge is that I really want four wheel drive and I thought to use an existing off-road chassis as a base, but I need independent double wishbone suspension at the front and something custom in the rear to allow the jet drive unit to fit. Nothing off the shelf springs to mind as being suitable. The undertray/lower hull section and body/upper hull section would be 3D printed. I also wanted a fully detailed interior. But it is the electronics and control system set-up which is the biggest challenge for me and figuring that out is going to be a critical aspect of the project.

I did consider that a much simpler way to achieve what I want could be to use a gearbox that allows selection of front wheel drive or rear wheel drive. In this scenario, for land use the motor would drive just the front wheels. Then for water use, switch to rear drive only and the output would be connected to the impeller of the jet drive unit. That would simplify things quite a lot but having just front wheel drive would seriously limit off-road performance.

 

[ferp420]

the biggest challenge for me and figuring that out is going to be a critical aspect of the project.

thats the easy part its all in the radio lots of radios have these features built in and there not that exspensive or that hard to program lots of tutorials on you tube
these settings are used in composition crawlers called MOAs or motor on axle crawler the almost all have 4 wheel steering and 1 motor for the front axle and one for the rear axle and you can control each motor or steering seperate from each other
the radios are already programmed to run this set up so its just telling the radio what you want the buttons to do
the better the radio the more settings you have to play with but even the cheap radios can do this as long as they have the channel mapping feature

 

[Gula]

As ferp420 sed, we need pictures! A sketch with crayons is better than what we have now. Custom scratch build off of something that's existing, or cradle to the grave 100% custom 3d printed build? Any cad renderings?

What scale are you looking at buildi g this in? More details of the vehicle, as the electronics seem a no brainer with todays radios.

On my build i had the same issue of figuring out how to put the 2 together jet drive and 4x4. Have you looked at some of the vintage kyosho belt drive 4x4 buggies? Or do trailing arms in the rear with the rear diff up foward like in a sandrail.