When developing a design it can be an incredibly useful skill to analise how & why a part/design failed and learn from that.
I wanted to make an improvement to the quadcopter since the timber arms, although cheap to replace, tend to break too easily. The main problem is that on impact the force tends to split the timber where it mounts into the hub.
I came up with a quick printed arm design and then did some testing. This also gave me a chance to compare the real life results with the FEA simulation. Here are the results. Continue reading FEA Simulation & Real Life Testing
As can be seen from the photo above, the new mounts are solid around the screw holes and much stronger. Continue reading Stronger Motor Mounts
More success came with re-flashing all the ESCs with “kda_nfet” firmware. There is a nice little socket which fits over the AVR chip with pogo contacts but I did it the hard way to make sure it worked before spending any more money.
What’s the best way to test if a device is strong enough?
Use it until it breaks. make the broken part stronger, then repeat. Continue reading Quadcopter Success (Part-1)
The quadcopter has been frustrating me a little. The ESCs still shutdown with random faults and the motors stall on start-up. One of the solutions I found was to disarm the controller, arm the controller and then give the transmitter a big hit of throttle whilst holding the quadcopter down with one hand. This sometimes had enough torque to get all motors spinning but wouldn’t always work and was quite hazardous having four blades with ~650Watts of power behind them. The last occasion I tried this a propeller blade flexed, the motor wires on the boom moved a enough to catch and a broken prop was the result. The broken blade was later found several meters away. Continue reading Quadcopter Still a Work In Progress
Yesterday was much more successful with the quad-copter project.
There was still a few intermittent problems with motors not being able to spin up. I gave the battery a charge to make sure it wasn’t the LVC (low voltage cutout) causing the problem but that didn’t solve it.
Next I used the programming card to re-programme the settings in the ESCs (electronic speed controllers). The first time didn’t work and the limited instructions weren’t much help but a second attempt was successful. Tip – double check the jumpers are in the right position on the programming card and leave it long enough to properly program the settings.
The final result was a few successful hovers at around 1.5m altitude (this was just testing it in the common area in front of our house and there were hazards like cars and small children nearby to limit the flights). Initially it had a nasty oscillation in the roll axis but adjustments to the PI settings in the KK2.1.5 control board reduced this. Further tuning in a suitable area will have it flying well.
Above is the initial assortment of parts. I already had the transmitter and just added another receiver.
The original landing gear used “pop-sticks” as the sprung element in the gear. These weren’t strong enough in the initial tests and the landing-gear was redesigned.
The Anycopter build is great as a simple first time build to get started. I recommend watching the FliteTest video on the construction. I’ve learnt a lot and can already see areas I want to improve on to customise it for my planned usage.
Today I also had a successful lift off with the prototype quadcopter.
It’s based on the Anycopter design from Flitetest.com. With my custom designed 3D-printed motor mounts and landing gear. The gear uses fibre-glass rods salvaged from a kite that didn’t fly too well.
The landing gear works well but the ESCs (Electronic Speed Controllers) seem a bit delicate. Self-leveling was switched off on the KK2.1.5 control board and there were a few rough landings, now the front two props aren’t spinning.