go_away

Author Topic: Can the Axon work with radio control?  (Read 3731 times)

0 Members and 1 Guest are viewing this topic.

Offline Razor ConceptsTopic starter

  • Supreme Robot
  • *****
  • Posts: 1,856
  • Helpful? 53
Can the Axon work with radio control?
« on: August 28, 2008, 02:14:16 PM »
I'm interested in used the Axon as a little link between the RC reciever and the servos. The reciever's servo outputs would be connected to the Axon, and the Axon would output those signals through its own outputs. Could something be programmed for that to work?
The reason I want to know is because the Axon could be the brains of an RC UAV. GPS/accelerometers/gyros could be connected to the Axon, and the Axon would adjust accordingly to stabilize the UAV. The problem with most UAV controllers is that they require a single PPM stream from the receiver, however some receivers do not have a single location where that PPM signal could be extracted. I was hoping the Axon could read each of the servo outputs from the receiver, and interpret those signals.

Thanks!

Offline airman00

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 3,653
  • Helpful? 21
  • narobo.com
Re: Can the Axon work with radio control?
« Reply #1 on: August 28, 2008, 04:52:13 PM »
yea the axon can

what you would do is connect the output of the receiver to an analog channel ,read the signal and according to that the servos move. Its very simple and we can't walk you through it if you need it.
Check out the Roboduino, Arduino-compatible board!


Link: http://curiousinventor.com/kits/roboduino

www.Narobo.com

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,658
  • Helpful? 169
    • Society of Robots
Re: Can the Axon work with radio control?
« Reply #2 on: August 28, 2008, 08:06:42 PM »
Quote
Its very simple and we can't walk you through it if you need it

What airman00 meant to say is, we *can* walk you through it. ;D

Go here and scroll down halfway:
http://www.societyofrobots.com/remote_control_robot.shtml

And use this schematic:


You will not get good resolution however, so just use an opamp to boost the output signal if you need it higher.

Another method you can use is digital inputs with timer-based interrupts to measure the servo signal pulse width.

Offline airman00

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 3,653
  • Helpful? 21
  • narobo.com
Re: Can the Axon work with radio control?
« Reply #3 on: August 28, 2008, 09:50:15 PM »
Quote
Its very simple and we can't walk you through it if you need it
What airman00 meant to say is, we *can* walk you through it. ;D

whoops typo.   :P
Check out the Roboduino, Arduino-compatible board!


Link: http://curiousinventor.com/kits/roboduino

www.Narobo.com

Offline Razor ConceptsTopic starter

  • Supreme Robot
  • *****
  • Posts: 1,856
  • Helpful? 53
Re: Can the Axon work with radio control?
« Reply #4 on: September 04, 2008, 03:41:26 PM »
Thanks for the info  ;D
Still saving up for the Axon, not much left to go, but will the response speed be slow? It doesnt need to be blazing fast but if the latency is over 70ms it might be a little problem. I'm intending to use this for a helicopter UAV. For autonomous mode latency isnt an issue since the transmitter isnt controlling the heli, but in manual mode the latency should be 100ms at max, including the latency of the radio itself (about 30ms). Will this be an issue?

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,658
  • Helpful? 169
    • Society of Robots
Re: Can the Axon work with radio control?
« Reply #5 on: September 04, 2008, 03:49:47 PM »
Latency won't be more than 2-3 ms, worst case scenario.

Offline bldavis

  • Jr. Member
  • **
  • Posts: 22
  • Helpful? 0
Re: Can the Axon work with radio control?
« Reply #6 on: September 04, 2008, 05:28:15 PM »
I am attempting somthing similiar to this and wanted to know what you were planing to do about altitude adjustments and landing configuration, or were you attempting to do that portion of the flight manually!
sounds like another awesome project, let me know what you come up with, i working on a plane so i have a few other problems. have a good one. ;D
- Website under construction -
http://www.mysapce.com/davisbe98ta
check me out on face book!!!

Offline Razor ConceptsTopic starter

  • Supreme Robot
  • *****
  • Posts: 1,856
  • Helpful? 53
Re: Can the Axon work with radio control?
« Reply #7 on: September 04, 2008, 08:33:49 PM »
Most of this UAV stuff will be in the future (next few years) as I get used to the Axon and get funds for the $$$ gps and other gadgets. What I was planning was for hands off hover (i'm focusing on helicopters, if i wanted a plane autopilot i would just spend $400 on a picopilot), I could use a laser rangefinder. While in foward flight, the terrain could change a lot, so a barometric sensor (or something of that sorts) could be mounted above the rotors and out of turbulence.

Landing will probably consist of getting it into a hover over the landing position (through gps), and then manually land it. Of course all of this will once again be a long time from now, the basic UAV helicopter needs a 3 axis gyro and accelerometer along with the altitude holder and that might take a while to get funds.

I'm sure with the plane you can just get it to circle over you, and then manually take over for a landing. Auto landing is really hard, as you have to hit the right spot in the runway so that you dont run out of space, or you land before the runway. Also crosswinds are easy to overcome in manual landings, but an auto landing with crosswind is difficult (usually needing some windspeed indicator to determine which way the wind is blowing)

Offline Razor ConceptsTopic starter

  • Supreme Robot
  • *****
  • Posts: 1,856
  • Helpful? 53
Re: Can the Axon work with radio control?
« Reply #8 on: September 29, 2008, 06:51:44 PM »
Quote
Another method you can use is digital inputs with timer-based interrupts to measure the servo signal pulse width.

How mechanically complicated is that to build? The analog one you mentioned needs a resistor and capacitor for each channel, along with an opamp for each channel... and I will be using 7 channels. That might get a little crazy. I'm assuming connecting it to digital inputs would get rid of the resitors and capacitors, but will I still need to use opamps?

Also the Axon does have 7 digital inputs right - I can use part of the 16 ADC's?

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,658
  • Helpful? 169
    • Society of Robots
Re: Can the Axon work with radio control?
« Reply #9 on: September 29, 2008, 08:12:23 PM »
Quote
How mechanically complicated is that to build? The analog one you mentioned needs a resistor and capacitor for each channel, along with an opamp for each channel... and I will be using 7 channels. That might get a little crazy. I'm assuming connecting it to digital inputs would get rid of the resitors and capacitors, but will I still need to use opamps?
You won't need any additional hardware to do this. It'll tie up a timer and an interrupt, so it *might* cause debugging problems if you had any other interrupts running.

Quote
Also the Axon does have 7 digital inputs right - I can use part of the 16 ADC's?
Every I/O pin on the Axon can be used as a digital input, including the ADC, so thats 50+. However I believe you are specifically looking to use a hardware interrupt, right? If I remember right, there are like 18 or so of them. Just look at the datasheets.

 


Get Your Ad Here