Replies to This Discussion

DeveloperPermalink Reply by Doug Weibel on April 7, 2010 at 11:12am

DIY Helicopter IMU's are still pretty cutting edge. Sounds like you have a lot of research to do. You don't provide enough info about your goals to suggest any components.

• ▶ Reply

Permalink Reply by Ravi Gaddipati on April 7, 2010 at 12:28pm

Sorry about that.

This is for a quadrotor. My main goal is to get a neural network based flight control, and then later implement surface vehicle/air vehicle co-operation.

Here was my original plan: http://rp181.fortscribe.com/?p=447

• ▶ Reply

Permalink Reply by Roy Brewer on April 8, 2010 at 8:34am

Ravi,

I am also interested in the answers you seek (I'm working on an autonomous quadrotor project). If I find anything out I will let you know.

The deg/sec tells you the nominal maximum values of the sensor. Since the output has limited resolution (its either read by A/D converters, or sent digitally) the max value also effectively sets the sensitivity (deg/s/bit)

Also, have you seen this: http://mbed.org/? Looks like it might be more powerful and cheaper than the sparkfun board (note: I am not an expert in these ARM chips - I just happened to notice this)

- Roy

• ▶ Reply

Permalink Reply by Ravi Gaddipati on April 8, 2010 at 5:35pm

I took a look at the mbed board (never looked into it). Its not more powerful, but powerful enough depending on the application.

I think I may start with that, as I dont need a programmer, and it cuts cost and weight.

• ▶ Reply

Permalink Reply by Don LeRoi on April 8, 2010 at 9:34am

Ravi and Roy,

May I suggest you look at the MikroKopter and UAVX flight controllers for ideas on what sensors to use? These are arguably the most advanced open source quadrocopter platforms. I have both. If you need links, let me know.

- Don

• ▶ Reply

Permalink Reply by Ravi Gaddipati on April 8, 2010 at 3:41pm

Thanks! I looked at those quite a bit, and another one I found. From what I read and Roy told me, I narrowed it down to these:
http://www.sparkfun.com/commerce/product_info.php?products_id=9269
3x http://www.sparkfun.com/commerce/product_info.php?products_id=9058

These are ADXL335 (accel) and ADXRS610(gyro) sensors.
Can someone confirm this?

I have another question. I looked around, but can't find how brushless motor controllers (TURNIGY ones from hobbyking) take input. Is it PWM?

• ▶ Reply

3D RoboticsPermalink Reply by Chris Anderson on April 8, 2010 at 3:48pm

Yes, it is PWM.

There are tons of quad projects already out there, including loads of IMUs that you can buy already made. It makes no sense for a beginner to start one from scratch at this point. Keep reading and you'll save yourself a lot of time and trouble.

• ▶ Reply

Permalink Reply by Ravi Gaddipati on April 8, 2010 at 5:28pm

I prefer making everything my self, it helps me learn much better. I don't just wan't a quadrocopter, that would get boring for me, I like actually making it (like my railgun project). I already designed a frame:
http://rp181.fortscribe.com/?p=458

I have been thinking about micro controllers (first time to MCU's, not programming though). What do you guys think of the mbed (http://mbed.org/nxp/lpc1768/) as a central processor? It has decent program space, enough PWM, ADC's for the sensors, UART (LCD display, GPS) and a Ethernet port (I may experiment with Ethernet bridges for a ground master and Arial slave).

I researched, but would like input from people experienced with quadrotors.

• ▶ Reply

Permalink Reply by Earl on April 8, 2010 at 6:14pm

Have you looked at this?
http://www.diydrones.com/profiles/blogs/arduimu-quadcopter-part-ii
Earl

• ▶ Reply

Permalink Reply by Ravi Gaddipati on April 8, 2010 at 6:22pm

I have seen that. It is not quite as powerful as I want, as I plan on working on kalman filter's (know someone who specializes in kalman filters and ferroelectrics, so thats a huge benefit) and implementing a Scale-invariant feature transform for basic recognition from the camera. This is a testbed, i expect to grow out of the mbed, but its a starting point.

• ▶ Reply

Permalink Reply by Jack Crossfire on April 8, 2010 at 6:44pm

If you know what you're doing, you can make them out of any gyros. The key is knowing what you're doing.

• ▶ Reply

ModeratorPermalink Reply by Roberto Navoni on April 10, 2010 at 5:45am

Hi Ravi,
see my project and repository I think that you can found some thinks interesting for your project : http://code.google.com/p/lnmultipilot10/
Regards
Roberto

• ▶ Reply

• ‹ Previous
• 1
• 2
• Next ›
• Page