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2 ESCs on one receiver.

J

JoeConti

Quarry Creeper
Joined
Jul 28, 2014
Messages
345
Location
Malta
I am in the process of modifying a recently purchased toy-grade forklift. The steering is BAD and so is the drive control. Another problem with the steering is that is it rear-wheel steer with front-wheel drive with a locked diff. Imagine the turning circle on that hahaha

So I am thinking a motor on each of the drive-wheels controlled separately. I am assuming I would need 2 ESCs (going for the cheap and well proven Hobbywing 1060) to control each motor.

I use a Spektrum DX8 radio which I had originally bought to fly quadcopters and when I moved over to crawlers, I continued using that same radio. For those knowledgable about the DX8, I use the rudder channel for steering and the elevator channel for forward and reverse while the radio is set in Mode 2.

I would want to continue using the same method for forward and reverse and steering, and will, later on, decide which channels to use for life and tilt.

I'm assuming that I will have to do some mixing to control 2 channels, one for each ESC, with my ELEVATOR channel and when I steer left, the left drive wheel will spin slower or the right drive wheel faster and the same idea for when I steer right.

Am I on the right track?

Here's a pic of my forklift.

202061012636.jpg
 
i think you would need a radio that has tank mode i dont know how you would steer the back wheels though cause the steering channel is used to mix the throtle and not run a servo maybe one of the gurus here will chime in with some actual knowladge on the subject

sounds like a realy cool project please do a build thread on it once you get it all figured out
 
ferp420 said:
i think you would need a radio that has tank mode i dont know how you would steer the back wheels though cause the steering channel is used to mix the throtle and not run a servo maybe one of the gurus here will chime in with some actual knowladge on the subject

sounds like a realy cool project please do a build thread on it once you get it all figured out
Click to expand...

Thanks for the info. Will do that :)
 
If you plan to run a motor to both the left and the right side... it means you're getting rid of the locked axle.
Maybe try it with 1 wheel drive?
I don't know where you're operating, but seems like anywhere this thing is being used, that should be fine. That's assuming that your steering issue is mostly the locked front axle and not lack of weight on the rear.

Seems like putting in a diff would be easier than running 2 esc and motors... but I don't know what the guts look like either.
 
chevy42083 said:
If you plan to run a motor to both the left and the right side... it means you're getting rid of the locked axle.
Maybe try it with 1 wheel drive?
I don't know where you're operating, but seems like anywhere this thing is being used, that should be fine. That's assuming that your steering issue is mostly the locked front axle and not lack of weight on the rear.

Seems like putting in a diff would be easier than running 2 ESC and motors... but I don't know what the guts look like either.
Click to expand...

Since I put up the first post, I took the thing apart and had a look at what makes it tick. The moment I saw the drive train I thought "FORGET TWO MOTORS HERE" and then thought of what you suggested "one wheel drive". It will only be driven on a flat painted wooden surface inside my scale garage and on the garage parking lot, another flat painted wooden surface. All I would have to do there is somehow disconnect only of the wheels and set it free :) That would give me the freedom of turning like an "open diff"

Steering, being a toy-grade is either full left or full right or off, straight. This will have to be changed for sure. I have done this on a 1/18th truck. The level of difficulty depends on how much space is left for a servo after removing the stock steering guts.

As for weight, yes it WILL need some added counterweight, but it looks like there is room at the rear under the body and also some scale accessory on the back on top of the body behind the driver. Stacks of room :)
 
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I know you already ruled out 2 motors, but incase you go back to it you would need a tank mixer like this:
https://www.amazon.com/Quickbuying-DasMikro-RC-Bidirectinal-Control/dp/B0754HVZ3B
It allows you to drive 2 ESCs from a throttle and steering input from the radio.

Normally these mixers will make a tank spin in place if you turn by running one motor forward and one backwards. This mixer has a feature I hadn't seen before and you would want for this project.
"Applying rudder at low throttle will NOT cause either output to cross over to the opposite direction." You would want this since you will still have steering and you don't want a full tank drive. The mix ratio would be like adjusting the diff. It is adjustable between 33-100%. It can't go this low but 0% would like having a solid axle. 100% would make it so that full steering would only make the outside motor spin.
 
robert@castle said:
I know you already ruled out 2 motors, but in case you go back to it you would need a tank mixer like this:
https://www.amazon.com/Quickbuying-DasMikro-RC-Bidirectinal-Control/dp/B0754HVZ3B
It allows you to drive 2 ESCs from a throttle and steering input from the radio.

Normally these mixers will make a tank spin in place if you turn by running one motor forward and one backwards. This mixer has a feature I hadn't seen before and you would want for this project.
"Applying rudder at low throttle will NOT cause either output to cross over to the opposite direction." You would want this since you will still have steering and you don't want a full tank drive. The mix ratio would be like adjusting the diff. It is adjustable between 33-100%. It can't go this low but 0% would like having a solid axle. 100% would make it so that full steering would only make the outside motor spin.
Click to expand...

Your idea sounds interesting and challenging. I will not let it go just now but will keep it in mine and do some research on how I could possibly do this, even if it's just 2 motors attached to an ESC and this mixer you mentioned all set up on the workbench.

Sadly there is no room for 2 motors side by side instead of the axle, but then I was thinking 540 motors hahaha - smaller ones perhaps but it would be very challenging to install them correctly and keep them secured.

Unless when I do is a sure thing, I would not like to cut up the plastic underside only for it to fail and then I cannot reverse what I did. I'd be left with a pile of trash :(

I'll try the one wheel drive approach for starters and take it from there, but like I said, its a great idea you mentioned above. I will give it some serious thought, if not for this project, who knows what comes next? :)
 
It sounds like you might find what you're looking for in the Sabretooth ESC. It comes from the robotics industry and is commonly used in Kyosho Blizzard upgrading.
 
I second the Sabertooth ESC if running two motors, it has built in signal mixing between channels 1 and 2. I have one in my Blizzard and it works exceptionally well in a two motor tracked vehicle. Not sure how it would work in the forklift application though since it has a steering axle. I would think an open diff or one wheel and steering servo would be more effective in this application.
 
Last edited:
Inspector86 said:
I second the Sabertooth ESC if running two motors, it has built in signal mixing between channels 1 and 2. I have one in my Blizzard and it works exceptionally well in a two motor tracked vehicle. Not sure how it would work in the forklift application though since it has a steering axle. I would think an open diff or one wheel and steering servo would be more effective in this application.
Click to expand...

This allows you to run your Blizzard off of a pistol, radio, correct?

I use a stick radio for mine, it works, but no matter how much I tweak the settings, it is still a bit twitchy.

What size motors are you running in your Blizzard, and what flavor of Sabertooth are you running?
 
Last edited:
Inspector86 said:
I second the Sabertooth ESC if running two motors, it has built in signal mixing between channels 1 and 2. I have one in my Blizzard and it works exceptionally well in a two motor tracked vehicle. Not sure how it would work in the forklift application though since it has a steering axle. I would think an open diff or one wheel and steering servo would be more effective in this application.
Click to expand...

Agree with you there - but will first try the one-wheel drive and keep your suggestion for future projects :)
 
Greatscott said:
This allows you to run your Blizzard off of a pistol, radio, correct?
What size motors are you running in your Blizzard, and what flavor of Sabertooth are you running?
Click to expand...

Correct, I'm just running the stock motors (haven't got around to upgrading those as I only use my Blizzard 2-3x a year) and 2x12A Sabretooth. Love it. Best upgrade for the Blizzard there is! It uses dip[ switches to prgam which is kinda old school but it works prefectly and you don't need sepcial cable or card or anything to make adjustments.

https://www.robotshop.com/ca/en/sabertooth-dual-12a-regenerative-motor-driver.html

Sorry for the thread-jack! Now, back on track - FORKLIFT STUFF AND THINGS!
 
Progress so far.

One wheel drive sorted. Only driving it on a flat surface so I'm assuming it will be fine.

Steering micro servo sorted. Had to use tue dremel to remove some plastic from tue chassis. Didn't wish to do that but it was then only way to go forward. Works now. Might need some tuning from the radio. Will see later.

Installed Hobbywing 1060 ESC and a receiver and rewired the forklift. Original battery was 4.8v. Not enough for the 1060. Cut some plastic out to make room for a 2S 1500mah lipo. Perfect. Drives like a a Rolls đź‘Ť

My next question is: I can see no way out from using an additional 2 ESCs for the boom and lift. Is there a small sized dual ESC I can use?
 
Decided to go the way of 3 ESCs. Ordered some today and boxed the project until the parts arrive, which could be a few weeks.

Thanks for your comments guys :)
 
Honestly I think just unlocking the front diff and controlling it with one esc would make quite a bit of difference. If you have dual drive in the front and one esc it's really not much different then an open diff either. The outside tire will rotate faster because it has less load on it, but it won't get stuck with one wheel spinning like an open diff.

You can wire the dual motors in parallel on one esc. If you don't like that you can alwayse add a second esc later. No clue on how to power one side less when your turning though, at least with rc electronics. An arduino could do that no problem, provided you know how to write the code.

__________________________
Handy gearing spreadsheet
 
For a small light esc maybe a quad copter esc would work. But you probably need a drag brake. Holmes and castle both have micro crawler esc's with dragbrake. The micro sidewinder 2 I think from castle. Br mini from holmes.

I guess both of these comments were too late to the party. [emoji14]

__________________________
Handy gearing spreadsheet
 
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