my 4 rotor autonomous vehicle, found same project online...please read!
J.T.
Posts: 31
Hi all,
Thanks for all your help.· I just recently saw that someone has completed the exact project I am trying to take on as a newbie.
The project is using the frame of a Draganflyer 4-rotor remote controlled helicopter and converting it to an autonomous flying vehicle.· Here is the link, please take a look at this...
http://www.seattlerobotics.org/encoder/200311/weimer/bxflyer.html
I have considered the propeller chip because it has multi-tasking, but for now I am going to try to build in a loop in PBASIC that will go through and check the sensors (this guy used a tilt sensor, but I'm leaning towards gyros) then will go set each motor speed for stability using motor speed controllers.
I'm looking for the right motor speed controller, but this guy apparently used something like a PWMPAL to drive 4 MOSFET's.· I'm trying to get a better understanding of MOSFET's to see if this is the way to go?· The HB-25 would be great, but I think it's too bulky for flight.
From the link, here is his solution to the electronics part that I am struggling with.
"I used a BX24 microcontroller because I'm familiar with it, it's programmable in Basic, it's (relatively) fast, it features floating point math and it has multi-tasking. I also used a serial connection from the BX24 to a PAK pwm co-processor. I then used the PAK to drive 4 MOSFETs. And, as I've already said, I reused the DraganFlyer motors and rotors. All this powered off the DraganFlyer's 9.6V rechargeable battery pack. Then the problems started. The motors generate a LOT of EMI - enough that they kept resetting the BX24 and the PAK. I could run one motor at a time - no problem. Two sometimes. But all four at once - forget about it! It took me over a year of playing around with various combinations of PCB boards, flyback diodes and noise suppression capacitors to finally get the thing to work!
My solution eventually involved putting flyback diodes and capacitors across the motor terminals and 0.1uF capacitors across the MOSFETs while running the PAK in "equal" pwm mode."
thoughts?· how would you go about this?
Thanks for all your help.· I just recently saw that someone has completed the exact project I am trying to take on as a newbie.
The project is using the frame of a Draganflyer 4-rotor remote controlled helicopter and converting it to an autonomous flying vehicle.· Here is the link, please take a look at this...
http://www.seattlerobotics.org/encoder/200311/weimer/bxflyer.html
I have considered the propeller chip because it has multi-tasking, but for now I am going to try to build in a loop in PBASIC that will go through and check the sensors (this guy used a tilt sensor, but I'm leaning towards gyros) then will go set each motor speed for stability using motor speed controllers.
I'm looking for the right motor speed controller, but this guy apparently used something like a PWMPAL to drive 4 MOSFET's.· I'm trying to get a better understanding of MOSFET's to see if this is the way to go?· The HB-25 would be great, but I think it's too bulky for flight.
From the link, here is his solution to the electronics part that I am struggling with.
"I used a BX24 microcontroller because I'm familiar with it, it's programmable in Basic, it's (relatively) fast, it features floating point math and it has multi-tasking. I also used a serial connection from the BX24 to a PAK pwm co-processor. I then used the PAK to drive 4 MOSFETs. And, as I've already said, I reused the DraganFlyer motors and rotors. All this powered off the DraganFlyer's 9.6V rechargeable battery pack. Then the problems started. The motors generate a LOT of EMI - enough that they kept resetting the BX24 and the PAK. I could run one motor at a time - no problem. Two sometimes. But all four at once - forget about it! It took me over a year of playing around with various combinations of PCB boards, flyback diodes and noise suppression capacitors to finally get the thing to work!
My solution eventually involved putting flyback diodes and capacitors across the motor terminals and 0.1uF capacitors across the MOSFETs while running the PAK in "equal" pwm mode."
thoughts?· how would you go about this?