ArduPilot/Research

Discussion of academic and industry research using ArduPilot

Brian Amin

@BAmercury

https://github.com/ArduPilot/ardupilot/blob/master/libraries/AP_AHRS/AP_AHRS.h

Ghost

@ghost~5e690156d73408ce4fdc6621

hey all, im trying to find out if its possible to run Ardu pilot on Arduino Nano 33 BLE Sense, it has all the sensors, AI, and the multithreaded OS. my main consern are the boot loaders, im not really worried about time execution, as i intend to re-write some Ardu Nano 33 code. ive asked in other chats, there is no reply, so, maybe here someone can enlighten me. cheers!

Andrew Tridgell

@tridge

@ghost~5e690156d73408ce4fdc6621 porting to that MCU would be possible, but would be quite a lot of work

marcsay

@marcsay

Hi, does ArduCopter use a certain waypoint follower algorithm when using Auto?

Giorgio Rinolfi

@n1ente

Hi All, we invite you to send us your suggestions and requirements to enhance ArduBee even more, we hope it will be a usefull platform for research, swarm and educational initiative based on ArduPilot https://discuss.ardupilot.org/t/ardubee-a-ready-to-fly-micro-drone-for-education-and-swarming/54362

Akshath-Singhal

@Akshath-Singhal

Can someone point me to where Guided waypoints are handled in ArduPlane? I wish to log the received waypoints to assess the performance of navigation controller. I am experiencing some discrepancies in demanded height for ArduPlane.

Emre Saldıran

@esaldiran

Hi @Akshath-Singhal , an external waypoint location given in Guided mode using MISSION_ITEM_INT messege type (same as dronekit simple_goto function) parsed at libraries/GCS_MAVLink/GCS_Common.cpp#L686 and passed to vehicle code at this function ArduPlane/GCS_Mavlink.cpp#L651. I belive you can continue from here. However, the externally send waypoints are already logged under NTUN message with TLat, TLong, TAlt fields

Akshath-Singhal

@Akshath-Singhal

I have plotted the target altitude and height demanded curves in the above image. The results seem to have some discrepancies.

TunaLobster

@TunaLobster

@Akshath-Singhal Look into tuning the TECS. It is one of the last things to tune before getting to proper Auto missions.

Akshath-Singhal

@Akshath-Singhal

@TunaLobster I understand that tecs tuning will help in better tracking. But here the problem is with the desired trajectory. The desired trajectory should have linearly increasing altitude as depicted in NTUN.TAlt but what I am getting from TECS doesn't make sense.

Please correct me if I am wrong

TunaLobster

@TunaLobster

I'm assuming that the ramp is made by a series of waypoints being given. Does the craft do the proper action if 1 guided waypoint at a different altitude is given?

Akshath-Singhal

@Akshath-Singhal

@TunaLobster Sorry for the late reply. Yes, a series of wp was given for creating the ramp. Giving 1 guided wp works totally fine.

Akshath-Singhal

@Akshath-Singhal

https://drive.google.com/file/d/1Ly39gifuS6bT-UXGLtJzb_oWPW9GFVff/view?usp=sharing

The link contains the plot for NTUN.TAlt and TECS.hdem

TunaLobster

@TunaLobster

@Akshath-Singhal Curious. What if 1 waypoint per second is given?

Akshath-Singhal

@Akshath-Singhal

@TunaLobster The results have improved but I dont know why there is a change of slope

Its weird. But I can still work with this. Thanks.

TunaLobster

@TunaLobster

To me that looks like a bug with altitude.cpp. I'm not fully up to speed on that part of the code, but it is not intended behavior. Tridge and Peter Hall were the last ones to work around that area. What was your original waypoint rate?

Akshath-Singhal

@Akshath-Singhal

It was around 250Hz earlier.

I guess @tridge can help us understand this better

Pierre Kancir

@khancyr

Use the proper mavlink message for guided position request, the missing item thing is just an old hack that should die...

Emre Saldıran

@esaldiran

@khancyr Is there any other way to send position command to plane in guided mode without using Mission item thing. Dronekit goto function and Plane autotest script also send position commands this way.

Pierre Kancir

@khancyr

my bad, plane still doesn't implement support on set_position messages ... I will fix that ...

Emre Saldıran

@esaldiran

Plane already support set_position messages, but it only processes the altitude field. I can add this feature without changing functionality.

Although, I never needed anything higher than 1 Hz for plane, I still can not see how high frequency guided command would cause oscillation in tecs height demand.

Akshath-Singhal

@Akshath-Singhal

@esaldiran I need high-frequency input to access the performance of the controller. What causes the oscillations isn't clear to me as well. It would be great if you could add the feature. Thanks.

Emre Saldıran

@esaldiran

What kind of input signal do you send to access the performance? What is the wingspan of your aircraft? The TECS algorithm is set to run at no more than 50 Hz(10 Hz for the most part). There is also LP filter with fixed cutoff frequency and 2 points moving average filter in the handling of high reference in TECS. So if you are gonna apply high-frequency sine wave it will be damped by these filters.

In the past, we obtain the performance of roll and pitch controller in Arduplane by sampling at 150 Hz. I think you can lower the sampling frequency. You can check our paper for more detail. A Model Based Flight Control System Design Approach for Micro Aerial Vehicle Using Integrated Flight Testing and HIL Simulation

Ed Muthiah

@ed-muthiah

Hi all, what do people normally use as an IDE for windows/linux if I wish to use both C++ and Python (ROS) files. Eclipse or VS Code?

soldierofhell

@soldierofhell

VS Code. I like also QT Creator for C++ and PyCharm for Python

marselomeri

@marselomeri

Hello, I hope you are doing all well! I am trying to change the physical model of the QuadCopter and use it in a SITL. Can anyone give me some hints and guidance on how to change the default model and implement a custom one? Thanks

Andrew Tridgell

@tridge

@marselomeri it depends what changes you plan to make. For small changes (eg. when we select "quad-fast") it can happen inside SITL/SIM_Multicopter.cpp

for larger changes it may be better to create a new model, or use one of the many supported external simulators

if you describe what you're trying to do I can help some more

marselomeri

@marselomeri

@tridge I am trying to change the quad configurations such as mass(weight) of the copter (I have seen its default value is 1.5 kg) and its maximum velocity limit.

Andrew Tridgell

@tridge

@marselomeri ok, so very similar to quad-fast, have you seen this? https://github.com/ardupilot/ardupilot/blob/master/libraries/SITL/SIM_Multicopter.cpp#L39

marselomeri

@marselomeri

@tridge Yes, I have seen it, but I was not sure. Should I change also how the hover thrust is calculated at Frame, or I just change the mass here and it will be updated automatically?

Andrew Tridgell

@tridge

@marselomeri the 2nd argument in that call is the hover thrust, if you want it lower just set it to a lower number instead of 0.5

TunaLobster

@TunaLobster

Oklahoma State University thesis titled "Design and development of a controllable wing loading unmanned aerial system" https://shareok.org/handle/11244/323829

11degouwd

@11degouwd

Hello, I am currently doing my masters and I am using a pixhawk cube for my project. I am wanting to create a new flight-control algorithm that will completely replace the L1 flight controller in at least one flying mode. It would be ideal if I could get this working for the loiter mode. I have read through the entire dev wiki and I have had a good look through the git repository. Unfortunately, I have not been able to see exactly which parts of the code I would need to change.

Would someone please be able to point me in the right direction and possibly give me some tips or pointers?
Are all the raw or filtered sensor measurements easily accessible?
Also how easy would this be to do?

Any help would be greatly appreciated

Akshath-Singhal

@Akshath-Singhal

@11degouwd It would be best to study the L1 control library properly, create a copy of it and make the necessary changes. Once you are able to get your controller working, you might want to proceed further by creating a pull request and taking input from developers.

11degouwd

@11degouwd

@Akshath-Singhal Thankyou, I will give this a go

Andrew Tridgell

@tridge

We now also have a research channel on the new ArduPilot discord server here: https://ardupilot.org/discord

Abhay Saxena

@aby03

I am writing my guided mode variant and I want to use it in mission planner but when i click on Fly to Here, it auto switch to Guided. Anyway to make it change to my mode?

Muhammad Mamoon Khan

@ememkhan_twitter

@ememkhan_twitter
Hey there everyone! I really need a favor,
I m working on SITL for Quadcopter and i need to customize the equations of motion and values according to my experimental quadcopter. I have calculated the values including inertial moments, mass, hover thrust, terminal velocity, rotational terminal velocity and arm length.

Luis Vale Gonçalves

@lvale

Hi there, more and more discussion is moving to discord so you are all invited to join us over there! https://ardupilot.org/discord

AshhadRasheed

@AshhadRasheed

hello, I'm new to ardupilot development. I've made a small customization in arduplane codebase and I'm looking to record its difference via X-plane SITLS, for that I need to create an input that i can test on the master and then i will have to recreate the same input for my own branch, my question is how do replicate the input in xplane SITLS?

liamf555

@liamf555

Hi all, this isn't directly related to Ardupilot, but I know people here have experience with RealFlight. My research is the use of reinforcement learning tor aerobatic flight manoeuvres for UAVs. With flightaxis, I can connect realflight up to my RL system and get it to learn. However, I'm currently seriously limited by the physics speed of realflight, unable to go 1.5x real life. Does anyone know of any way of running the realflight physics faster than this?

Andrew Tridgell

@tridge

just a reminder that the primary interactive discussion channels for ArduPilot is now on discord https://ardupilot.org/discord

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