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Help! If you have two FCs, please try this.

#1
I am doing project on two cooperative drones. In that I used arduino uno which I think is ok to learn but now I am facing a lot of issues. So I am thinking about switching arduino uno to ready to fly FCs. Before I buy FC , I need one confirmation and it is, to check that balancing bar stay in balance or not. Set-up for this experiment would be: connect 1st motor to the first FC's 1st or 2nd slote and 2nd motor to the second FC's 3rd or 4th slote. Must check torque balance. Any suggestions and thoughts are appreciated. Thanks.
 

makattack

Winter is coming
Moderator
Mentor
#3
I don't know what your experience with remote aerial vehicles, and flight controllers is, but as JasonK mentions, it sounds like you're starting to learn about them. Think about the problem you want to solve as similar to your use of computers. It's a very similar relationship to a single computer acting alone and a networked computer working with one other or more computers. If you have a single computer not connected to anything else, that's the same as a stand-alone UAS. If you want to network them, let's say for multiplayer computer games, or other such purposes, then you need to set the computers up to be able to communicate with each other or a central controller/server. Think peer to peer networks or a server based multiplayer video game. I use gaming / computers as an analogy because most people are familiar with those concepts, particularly when you are using a web browser to post to forums ;)

Of course, as with any technology, there are many ways to solve a problem. One could have UAS's be aware of each other without a direct connection to each other, by increasing the autonomy of them and having sensors that allow for them to "see" other UAS's and objects.
 
#4
that isn't how current FC software is written, so it won't work. if you have a rigid connection between the 2 sides, you would just use 1 FC to manage everything, if it isn't rigid, that won't work at all.

also, there are more answers to questions related to this in your thread here: https://forum.flitetest.com/index.php?threads/two-channel-for-pitch.67220/
WhatsApp Image 2021-08-02 at 9.45.12 PM (1).jpeg
WhatsApp Image 2021-08-02 at 9.45.12 PM.jpeg

i did small experiment with set up as shown in images. it has two motors, one arduino and one mpu6050 for each motor. the goal was balancing of bar and it works fine( better then i thought).
jasonk, you know well what i m trying to do. now,i am confuse what to do next as experiment. if you or anyone have any ideas,please tell me.
 
#5
I don't know what your experience with remote aerial vehicles, and flight controllers is, but as JasonK mentions, it sounds like you're starting to learn about them. Think about the problem you want to solve as similar to your use of computers. It's a very similar relationship to a single computer acting alone and a networked computer working with one other or more computers. If you have a single computer not connected to anything else, that's the same as a stand-alone UAS. If you want to network them, let's say for multiplayer computer games, or other such purposes, then you need to set the computers up to be able to communicate with each other or a central controller/server. Think peer to peer networks or a server based multiplayer video game. I use gaming / computers as an analogy because most people are familiar with those concepts, particularly when you are using a web browser to post to forums ;)

Of course, as with any technology, there are many ways to solve a problem. One could have UAS's be aware of each other without a direct connection to each other, by increasing the autonomy of them and having sensors that allow for them to "see" other UAS's and objects.
what you think makattack?
 

makattack

Winter is coming
Moderator
Mentor
#6
I guess I'm not sure why you would set this up in such a manner. Using a platform to mount the two sets of controllers, sensors, motors to simulate two independent "drones" doesn't really simulate what you're trying to setup up. The "communications" between the two systems, that I noted is effectively what that rigid balance bar implements, but you have not implemented that interface between the two arduinos if they were separate drones.

Definitely nice work getting this experiment working, though!
 
#7
View attachment 204614 View attachment 204615
i did small experiment with set up as shown in images. it has two motors, one arduino and one mpu6050 for each motor. the goal was balancing of bar and it works fine( better then i thought).
jasonk, you know well what i m trying to do. now,i am confuse what to do next as experiment. if you or anyone have any ideas,please tell me.
Looks like a Uni experiment I saw in Sheffield a few years ago
 

LitterBug

Troll Spammer
#8
Dunno... I have flown bicopters with a single FC which had a single MPU6000, two motors, and two servos. Looks like a lot of work for something that isn't hard to do.


LB
 
#9
I guess I'm not sure why you would set this up in such a manner. Using a platform to mount the two sets of controllers, sensors, motors to simulate two independent "drones" doesn't really simulate what you're trying to setup up. The "communications" between the two systems, that I noted is effectively what that rigid balance bar implements, but you have not implemented that interface between the two arduinos if they were separate drones.

Definitely nice work getting this experiment working, though!
thanks for the compliment makattack.

i had idea that if i want to replicate cooperative drones ,i need communication medium between two FCs.but i did that experiment because i was not 100% sure that will it work or not. but it works perfect.

now i am ready to go forward but i don't know which FC i use for next experiment(which include communication between two FCs).i am thinking to use betaflight or pixhawk because i don't think arduino can do that with good stability.

if anyone have idea which FC is more suitable in terms of communication between two FCs and modification of code or want to suggest other FC, please put some light on that.thank you guys.
 

clolsonus

Well-known member
#10
Small arduino boards are as stable as anything else. The reason to go to a more expensive flight controller would be a faster processor and more memory as well as integrated IMU and other sensors + easy to plug in even more sensors like gps, airdata, etc. (So if you have enough memory and speed on the boards you started with and are happy with the IMUs you have, there may be no necessary reason to upgrade to soemthing fancier.)

Arduino boards can communicate with each other just as well as any other boards. You just have to decide how you are going to setup the communication. Are you going to use i2c? serial/uart? Then match the speed and write code to read/write packets. It is a pretty common task in the embedded world. One thing to pay attention to when communicating between boards is your TTL voltage level. A lot of simpler arduino boards use 5v ttl for signals, whereas many of the newer flight controller boards use 3.3v. Often you can plug these signal lines together and it just works because the chips are tolerant enough of voltage variations, but it's worth paying attention to and knowing what's going on so you can debug or fix if there are problems. I've had to use level converters for some projects from time to time.

Another reason to look at higher end flight controller boards is that px4 and ardupilot both provide extensive functionality and support for just about any vehicle configuration you can imagine. So be clear with yourself if this is a project where you want to learn how to make all the basic building blocks of a flight controller yourself (which is a great thing I think) or if you want to do something higher level. A good flight controller ecosystem can help you leap frog all the low level stuff and jump straight to the higher level work. It really depends though on what you are hoping to accomplish. Some people just want to go straight to the flying part as quickly as possible and that's great too.

I agree with those that suggest that you can do this with a single board. I wasn't quite seeing your motivation for two boards and two IMUs ... but if you have an interesting idea you want to pursue, that's great ... this is the extremely valuable process of learning in action!

My advice is to be extra careful with props! Especially in any project where you are writing your own code to control the motor speed ... any little glitch or program crash or mistake could run your motor at an unexpected time (or leave your motor running full tilt after you program dies.) So please leave props off unless absolutely necessary in final testing or until you get to the flying field for real world testing! Make sure you know how to deal with a runaway motor. Don't ask me how I know about this, but my spouse was not happy with several large gashes in our leather couch in the basement ... thankfully it was the couch, not my arm ...

Good luck!