Btw, the drawback of a drone/quadcopter is the legislation limiting where you can fly. And if you’re at a track meet…you can’t fly over people without a waiver which is relatively rare.
An RC car can also have a much better battery life as you can haul around much more weight.
This would only be used on an empty track with my roommates, so I’m not worried about that, but yeah the battery life would be much better on a car and it would be more durable.
I think I have enough knowledge now to try this myself, so to recap.
In order to replicate, dave’s track experiment I need:
A Redcat RC Truck 1:10 scale
( large enough to hold the extra equipment ) if there are better vehicles for driving fast, but gradual curves let me know
F7 Autopilot Controller: Link above
One of these GPS Systems, probably the better one if I can make the GPS work properly:
Here2 GPS GNSS Link above $95 - 2.5m Resolution
Here+ V2 GPS $275 - 2.5cm Resolution
A good battery for the Autopilot controller.
Solder Kit
Wires
Download Mission Planner
Am I missing anything?
If you want fast and stable in turns, crawlers aren’t the best. The slash with an LCG chassis i posted will be better for speed and turns. Both will likely work…but crawlers will be more speed limited and worse at cornering due to high center of gravity.
Edit: if you never care about offroading, a 4tec2.0 or similar road racing car would be great.
You can use an F7 or something like a pixhawk mini. Your autopilot choices are pretty broad, but a pixhawk variant is going to have much more documentation.
You need a GPS but you dont necessarily need a here2 unless you really want centimeter level arruracy which is the here2+. Something with a NEO M8N will work…the holybro pixhawk 4 gps is only $50ish and its good.
You can use the RC car battery for the autopilot if you want. Autopilots like the Pixhawk 4 mini come with a power management board that takes the on board battery and splits some power off to the autopilot with the rest going to the rc car. This requires soldering and the board is capable of supporting 4 ESCs. Your RC esc will power the servo rail of something like a pixhawk mini. I use a separate battery though because I wanted a modular setup.
You may want servo extensions to limit soldering and allow easy disconnects.
A telemetry system ($40ish I believe) is great because then you can just connect to the autopilot with your cell phone and use qgroundcontrol to plan missions. No need to lug around a computer.
I agree with Sean about the vehicle for your use case. You don’t need 4wd or slow speed crawling control so a 2wd vehicle would be a better choice.
I like the F7 AIO (All-In-One) boards for several reasons. They take battery power directly so you don’t need a power module (another piece of hardware to package), they have voltage and current sensing built in, they have a couple BEC’s to power external things and not that you need it it has OSD integrated also. And they are affordable at ~$50. I have Pixhawks, PixRacers and several of these other F4/F7 boards and they all have their place but the technical requirements for a Rover are light compared to a multirotor or Plane.
I would start with a M8N GPS. I have one of the HolyBro units and it’s good. This Rover has a Here GNSS but nothing special about them.
You will need an RC System. You can control the vehicle with a Ground Station but for setup and configuration you really need RC. I use a Radiomaster Transmitter and Frsky Receivers which puts all the telemetry you need right on the radio screen. It’s handy, I don’t use a ground station in the field anymore unless I need to change some parameters but even that is possible from the radio now.
Good reminder on the radio. I use a turnigy 9X…and while its low cost and works…theres a lot to be desired. I think I would go with something else…even better if its an RC car style remote.
Ouch, that would strip the spur gear in my truck if it had good traction.
I think you would be OK in that respect. The issue only occurs at/near zero velocity. I typically see it happen when starting a mission from stop - the vehicle starts in the wrong direction and reverses indefinitely, obviously never reaching the target WP. In these cases I would simply stop the vehicle and try again and once moving forward it would be fine. i now have the issue fixed in my version of the code but my pull request to fix this issue in master has not been accepted yet
What do think of the Slash 2wd for this application? Love the Ford Raptor version.
Sorry, replied to the wrong post.
I don’t know how I missed that. Nice looking vehicle and it would seem to be a good platform for Jason’s needs.
Thinking about it further if he has free Ntrip service available as I do that would be the most economical way to get RTK working. You wouldn’t need long range telemetry for a Track, any radio would do. That’s the problem with longer range needs to serve the correction data, the telemetry sysyem required get’s expensive on top of the expensive GPS module.
I have operated a rover on an athletics track using an on-board ESP32 running an ntrip client connected to a wifi hotspot on the phone in my pocket: RTK vs M8N Comparison - Rover
If you are on a budget and want a GNSS with built in multi frequency RTK then I have had good results with: http://navspark.mybigcommerce.com/ns-hp-gn2-px1122r-multi-band-quad-gnss-rtk-breakout-board/ for $125USD (+ antenna)
Nice project!
Following.
I’m using a matek f765, but as mentioned in this thread already… check for an f4 or f7 based fc.
If you plan to expand in the future I would go for f7 for the extra uarts.
I don’t think my rover can get to 20kph, but if weather permits I might take you up on that challange.
We have a grass race track here.
I think you are fine with a “normal” gps… but i’m curious if you want it to be a little more precise on the path it’s following… you might need something more accurate.
Great project!
What Ntrip application are you running on your phone? I have ESP8266 radios on most RC models inc this Rover. Range is limited though, I use them for setup/configuration not really telemetry. Maybe put the phone on the vehicle?
Nevermind I didn’t understand the phone is just a hotspot and the RTK application runs on the ESP32. The question about putting the phone on the vehicle came up when I asked the GQC dev if support for Ntrip could be added as it is in Mission Planner. Then an onboard iPhone (what I have) would work.
Yes, I wrote an NTRIP application for the ESP32. It would be nice if QGC had an integrated ntrip client but in the mean time if you have a USB port on your GNSS module, you could look at using an android NTRIP client connected via OTG (including a hub if you also have plans to use QGC concurrently). I have used the U-Droid Center to send corrections to a Ublox F9P in this way.
Parts List Version 2
In order to replicate, dave’s track experiment I need:
Traxxas Slasher 1:10 scale (I believe this is a 2WD) $240
( large enough to hold the extra equipment )
F7 Autopilot Controller Board: Link above $50
GNSS RTK GPS Board $125 (Antenna?)
Turnigy 9X Transmitter & Receiver (this is for telemetry?) $73
Run an Ntrip application on my phone (Android). Would this communicate over bluetooth?
Solder Kit
Wires
Download Mission Planner
You’ll want a telemetry set as well.
The back half of this video shows everything I used in more detail and covers the telemetry module.
What does it take to get spline waypoints for Rover?
I have a high-performance vehicle I would like to automate, but have been put off by lack of success with anything Rover besides low acceleration, low-speed vehicles. This seems ironic because high-po quadcopters, helicopters, and airplanes all seem to work fine with ArduPilot and those are much more complex control solutions.
Put in an enhancement request (PR). But perhaps the new navigation controller with S-curve will be an improvement anyway. It’s in Copter Master, not sure actually if it’s in Rover Master.
