Discussions

Scratch Built Quadcopter with Inertial Position Tracking

Posted by Phillip Schmidt on March 19, 2012 at 1:46pm

Hi all,

A couple of weeks ago I got bit by the bug to build a quadcopter from scratch. I am purchasing the motors, ESC, battery, propellors, ect..., but I am designing and building the frame from raw materials. I am programming the control system from a blank slate. One of the things that will make this quad different than many others is that I will be attempting to track it's position in relation to it's start point purely from the accelerometer and gyro. If that feature is successful, I plan to add the ability for it to fly autonomously by following pre-programmed way-points. If the inertial position tracking doesn't work out, I'll just reprogram is to use standard Quadcopter controls and have fun with it.

Here's a link to my Blog where I am writing about the process:

http://philstech.blogspot.com/2012/03/quadcopter-project-overview.html

Let me know what you think.

~Phillip

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accelerometer, ipt, inertial, position, quadcopter, tracking, gyro

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Replies

Phillip Schmidt June 26, 2012 at 2:14pm

My latest blog post discusses the final parts of the physical build for my Quadcopter.

http://philstech.blogspot.com/2012/06/quadcopter-build-status.html

~Phillip

Quadcopter Build Status

A blog about technology focusing on multicopters, my quaternion based IMU, and any thing else that catches my interest.
Phillip Schmidt June 21, 2012 at 1:50pm

My latest quadcopter post is up.

It discusses why inertial position tracking is not feasible with my current hardware. This article will come as no surprise to some of you. I have ideas I still want to try, but for now I will program my quad to use standard controls and have fun with it.

I have no regrets with about trying. It has been a fantastic learning experience.

http://philstech.blogspot.com/2012/06/quadcopter-inertial-position-...

Quadcopter: Inertial Position Tracking - RIP

A blog about technology focusing on multicopters, my quaternion based IMU, and any thing else that catches my interest.
Phillip Schmidt April 7, 2012 at 2:25pm

Latest post discussed accelerometer filtering.

http://philstech.blogspot.com/2012/04/quadcopter-accelerometer-data...

Quadcopter: Accelerometer Data Filtering

A blog about technology focusing on multicopters, my quaternion based IMU, and any thing else that catches my interest.
Allen Babb April 1, 2012 at 7:22pm

What's the power rating, Kv, and operating voltage for your motors?
Marko Kleine Berkenbusch April 1, 2012 at 7:14pm

Hi Phillip,

Good luck with your project, I always like to see other scratch-builders! I am sure if you stick with it you can get to something that flies nicely.

Regarding inertial navigation/dead reckoning:

I think your goals are ambitious, but will be very difficult to reach. I have tried something similar on a 32bit MCU and haven't gotten terribly promising results. One of the big problems is the accuracy of the attitude estimate. Even if the pitch or roll angle is off by only 0.1 degrees (which would be a spectacularly good result for hobbyist-class IMUs) you would accumulate a location error of 1/2 mile in 5mi - with everything else working perfectly...

I think you will find that you really need other sensors to aid in the localization problem.

Marko
Phillip Schmidt April 1, 2012 at 4:59pm

The latest post details assembling the frame:

http://philstech.blogspot.com/2012/04/quadcopter-frame-assembly.html

~Phillip

Quadcopter: Frame Assembly

A blog about technology focusing on multicopters, my quaternion based IMU, and any thing else that catches my interest.
Phillip Schmidt March 29, 2012 at 11:59am

Latest post talks about my progress with the Inertial Position tracking:

http://philstech.blogspot.com/2012/0...acking_29.html

Quadcopter: Inertial Position Tracking Tech Update #1

A blog about technology focusing on multicopters, my quaternion based IMU, and any thing else that catches my interest.
Phillip Schmidt March 27, 2012 at 11:47am

Latest update just went up.

Quadrotor Post #6: http://philstech.blogspot.com/2012/0...and-motor.html

Quadcopter: Parts Arrive and Motor Mounts

A blog about technology focusing on multicopters, my quaternion based IMU, and any thing else that catches my interest.
Allen Babb March 19, 2012 at 7:34pm

I looked at your blog, and was curious as to what you do during idle time, where the core's not scheduled to process anything and is just waiting for the next scheduled time?

Also, you have to be careful about frames of reference. Remember that your IMU is giving you data relative to the orientation of the craft.
Greg Fletcher March 19, 2012 at 2:40pm

Due to noise levels in the accel signals and reletively low resoloution, I don't think this is possible with the sensors. You will have to double integrate the accelerations to get distance data and errors wittl add up very quick.