Ferry Spiering helped me redesign my circuit, specifically the powersupply circuit. Stability has improved, but I still get similar symptoms: shutdowns or resets if current draw gets too high. The shutdown's seem to originate from the batteries themselves, as they stop outputting 7.4V, and deliver less than 1V instead.
We did manage to spin up all four rotors when drawing power from a PSU though. I will have to recharge the li-ions, and re-run some tests. Also, we observed less problems when pulling the reset line of the AtMega high.
I am now spreading the message. Thanks to auvsi.org for the materials. I've tested the new voltage regulator, but see no improvement: if the current draw gets too high, the electronics switch off. Maybe it's a switch in the battery, maybe a switch in the PWM motor driver? The engines have been fitted into the new airframe. Also, the four props have been mounted. Electronics problems prevent me from testing the combined thrust of four engines (shut down after spinning up the 2nd engine). This is what prototype number 2 currently looks like:
Created engine mounts from plexiglas, and created new styropor frame. The styropor frame is now suitable for 2xCCW and 2xCW setup from the jul2002 design. Also, the custom made props from Braun Modelltechnik have arrived. They look great. The standard voltage regulator has been replaced by a better one with a lower voltage drop.
A new design for the rotor configuration (jul 02).
A log about my propeller conversion.
My first prototype had a design flaw in it. I used four WES technik props that all four were rotating clockwise. This causes a strong counter rotation of the craft. Also, the engine driver shuts down when starting the 3rd or 4th motor. I think this is because the voltage drop on the voltage regulator maybe critical. My guess is that at high currents, the battery delivers slightly less voltage, which results in a shut down of the voltage regulator.
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| components click to enlarge | frame from styropor click to enlarge |
