Servers by jDrones

Can I use 'standard' ESCs for rover?

Hi

Sorry if this is a stupid question, but I couldn’t see an immediately obvious answer in the wiki or in this forum.

Can I build a Rover around a standard FC/ESC combo? Say for example, I have a Matek F405-Wing flight controller which I use for ArduCopter and ArduPlane, along with a Typhoon32 (Blheli32) 4in1 ESC. This ESC is nice and neat - it sits underneath the FC and has neat wiring integration including telemetry.

I have this mounted in a 3d-printed frame (Free Stuff! Need Help Testing devFrame). What I’d like to do now is to do learning and development into DL/ML/AI, and it’s a lot safer (and cheaper in terms of replacing shattered parts!) to do this on the ground. I’d like to convert this copter frame into a rover, either using front steer or skid steer - or anything else if more suitable. The idea is to create a development platform that you can use to safely develop on the ground, and then easily and quickly convert to copter to fly developed software.

So, is it possible to use the same FC/ESC/frame stack, and build a Rover around this? The rover doesn’t have to be anything sophisticated - a crude skid steering brick to start with is absolutely fine.
Hopefully someone here will be able to advise if this is doable, or a stupid idea :slight_smile:

ps - the arms of the devframe linked above are easily changed to H pattern with a single screw, so I was hoping to add wheels onto the end of the arms through new 3d printed mounts. Possibly with shorter arms.

Sure you can, no problem with that. Of course they have to be brushless motors with those ESC’s. Many Rovers, like mine, have brushed motors and I use ESC’s for RC trucks.

Thankyou for the quick and non-judgmental reply :slight_smile: (I was bracing for rtfm newbie…)

With normal ESCs do you have to use special low kv motors, or gears? Could you point to a couple of suitable motors as examples that are widely available?

Are encoders a must for non-gps these days?

You will have to gear a brushless motor way down for use in a Rover. Something like a very low kV gimbal motor may work directly I suppose. I had a Rover I built from a Basher type truck with a brushless motor and it used one of these with some tall gearing:

What size vehicle are you planning? That 4in1 ESC won’t get much cooling on a Rover so consider that. RC Car/Truck ESC’s have large heat sinks, some have fans.

Most standard ESCs will have problems driving a gimbal motor. I tried it with different ESCs and the only standard ESC I found that would achieve rotation without stuttering was an old simonk ESC. It work for a few minutes and then a mosfet smoked. The next simonk ESC did the same. I did not try one of my VESC after that and they would have been to big for the mini rover I wanted to build anyways.
Building a rover from scratch with brushless motors is not easy. The only way to do it without gears of some kind, are hubmotors used for hoverboards. But hubmotors will most certainly not work with blheli ESCs. I recently bought two metal gearboxes meant for RC tanks. They come with brushed motors, but small brushless inrunners for 1:18 rc cars also fit. That could be a way to use brushless motors in a rover, without building gearboxes yourself.

That’s good info on controlling the gimbal motors. I was thinking they would be a good choice for a Balance Bot but it sounds like not. Plus Balance Bots seem to be problem plagued so I decided not to bother :grinning:

Small - 300-450 size. Certainly no need to cool the ESCs in flight, maybe on the ground a bit different?

It sounds like the high torque/low kv is what will cause problems with the ESCs, and if gimbal motors aren’t a goer (shame, as a lot of them have encoders now) then it looks like gears will be needed.

Could you point me towards an example of what I’m looking for re: wheels, gears and motors suitable to be driven by ‘standard’ ESCs? I’ve tried doing a bit of research but got nowhere quickly…

I really think this kind of thing would be a great way to get more propellor people into rovers, and a much safer way to get people into learning how to vision/ML code :slight_smile:

Most cheap and even not so cheap rover/robot plattforms use geared brushed motors with wheels directly attached to the output shaft of the gearbox.
Brushless motors with gearboxes are rare. There are some used in gliders, they are expensive and I would not use them for a ground vehicle. I also found brushless motors with integrated ESC and a worm drive gearbox.
The ways I know to use a standard or blheli ESC to run a rover is.

  1. Use a RC car
  2. Build your own gearbox
  3. Use the Taigen 5to1 tank gearbox
  4. Build a prop driven rover

Using a RC car is the easiest option to get something ready to go. Best would be a crawler, but they often use brushed motors.

Building your own gearbox is not that hard, but you will need some tools, parts and research on how to do it.
You could use spurgears, belts, chains etc.

Using the Taigen gearboxes is the easiest way I know to get a 4WD skidsteering rover with brushless motors.


A pair cost 60€ with brushed motors and a brushless motor from hobbyking that should fit costs around 10€. The output shaft is an 8mm D-shaft, but it steps down to 5 or 6mm inside the gearbox. And you can switch the position of the last gear to get two different ratios.

I have built a few prop driven land vehicles. It is mechanically the easiest way to build something that drives around, but not in rough terrain. You could use all copter parts you already have. The last prop driven rover I have built used a quad frame with square arms to mount the motors horizontal and a plattform for the wheels under it. It used the omni-x rover mixer and a blheli 4in1 ESC in 3D/bidirectional mode.

Please, tell us more :). Do you have any pics of previous builds?

The idea around the devframe project is to provide a flexible frame that you can hang lots of sensors/computers from, that anyone in the world can 3d print from opensource parts and put together with easy to find off the shelf parts. It’s really aimed at developers rather than racers/rock climbers, so as long as it can drive around a garage or driveway or flat garden, that would be a great start. I was hoping to reuse as much of my simple 330-ish size quad build as possible, but if it’s too difficult/expensive to reuse the ESC then maybe it’s just easier to move to a fresh set of ESCs and rushed motors. The beauty of the 4in1 esc of course is that provides PDB, ESC and easy to use connections to the FC.

Hi @fnoop,

I have the same idea to have the possibility to reuse the common components for quad and rover. Currently I have built a rover on top of Traxxas Stampede platform and use carbon tubes and fiberglass plate for electronics (together with 3d printed mounts). Next step would be to model the common mounts for devFrame and rover to quickly interchange electronic parts between them and to add a Jetson Nano for object avoidance / object recognition.


Anton

Hey @Jh_Dev - great! Any ideas you have would be great to see. The more I think about it, the more I think this is a crucial step for autonomous development - to be able to experiment and develop in the safety of ground vehicles before trying to fly!

Can anyone advise on a cheaper option to the Traxxas Stampede? It’s way too expensive to be a good starting point just as a dev platform, but it’s a really good idea (mounting a devframe ontop of an existing rover).

I think @ppoirier had sourced some cheap gear motors, speed control and caster wheel for some of his early experiments. There are cheaper rc cars out there but they will come with a cheap little radio and you will have hours trying to hack out the cheap stuff to make it work. And they are all made to run fast. You also pay for suspension which is not really needed for basic testing.

I would look at a Crawler. You don’t want a high speed vehicle (tried that). It’s not cheaper but my 2nd Rover is a Redcat Everest Gen7. Great platform for a Rover. But even at 5m/s I still run into things on Auto Missions. I don’t have RTK although its the plan as I have free Ntrip service here

Yes, there is cheap and crap… unfortunately it’s hard to differentiate between both :slight_smile:

I would go with POLOLU that offer good products at a reasonable price.

Hello gentlemen, I just read this post and have idea about using 3D ESC 40A from Hobbywing for rover. Using 3D ESC, the throttle stick is in the middle at neutral/zero rpm (but we can calibrate to adjust this condition). So we can move forward or backward from this neutral position. Other alternative is to use VEST ESC with brake regerating function. What do you think guys?

Hi @ton999 a lot (most?) of blheli ESCs will support bidirectional (3d) mode - even my 4in1 typhoon32 supports bidirectional. I think the real problem is how to get the ESCs hooked up to motors/gears/wheels that support brushless ESCs (which is what pretty much all flight ESCs are). I’m still not really any wiser on that so far :slight_smile:

I think most any ESC can be set for neutral at mid stick. Every Brushed ESC for cars and trucks works that way.

https://www.thinkrc.com/faq/brushless-motors.php

at the end of the day it’s easier and cheaper to build with and control brushed motors for ground rover at our price point.

to build a three wheel rover with caster you will very likely need a brushed ESC (with two motor outputs), two brushed motors and a caster to pivot.

would really like for someone to prove me wrong but that’s the current state of the art for cheap and easy ground rovers as far as I know.

you can reuse the devFrame main frame, flight control, RC and sensors. so there is a bunch of overlap, but not as much as what i think you are hoping to achieve.

Yea, brushed motors are easy to implement and make a lot of sense for a rover. They are relatively inexpensive, provide low RPM power and will run wet, or underwater for that matter. Pair them with a RC Truck ESC, which are typically waterproof also, and you have simple power for your build.

Servers by jDrones