Quadrocopter Drive

Instead of usually one drive in a plane you have four drives in a Quadrocopter. Simple statement, but it means four times the cost and synchronism is important.

In order to allow good control, the total maximum thrust value should have a factor of 2 to the total weight.

In order to have best price/performance ratio, I like to describe 3 sets of low cost drives.

Because reliability is most important in the case of a Quadrocopter, I like to say a few words about it.

Motor

The brush less motor should have a low kv (turns per minute per Volt) value, in order to reach a good efficiency. Because the air flow speed must not be high, because of limited vertical speed, a low kv value allow larger diameter propeller and therefore better efficiency. Click on the picture to show it in full size.

attachment:DC_DT750_GWS10x6HD_10-5V.png

attachment:DC_AX2213N_GWS9x5HD_10-5V.png

attachment:DC_AX2213N_GWS9x5HD_10-5V.png

At least from the measurement and calculation the 2213N shows the best efficiency.

ESC, Electronic Speed Controller

Propeller

All those mentioned propellers are from company GWS (HD type), or similar ones. I found that they have the best efficiency, when you look in the program Drivecalc.

Balance of the propeller is very important in this application. I cut off the heavier side some thin chips (upper side) with the help of a thin sharp steel plate.

Power Distribution

I like to have MPX plugs in the battery power distribution, see link, then it is easier to exchange an ESC. For the battery with high capacity now the XT60 plug is used, see link.

You should take care about a low voltage signaling, either with a buzzer on the MultiWii control, or external Voltage Detector, see link.

An other option is to have a currents sensor, which is supported by the MultiWii control. I am using a ACS715 break out board, see link. The output is an analog voltage (133 mV/A) that reads 500 mV for no input current and has a typical error of less than 1.5%. The sensor operates at 5 V, 10 mA.

Setup in config.h of MultiWii

/* PLEVELDIV ACS715 = 133 / 4.9 * 10e6 / 19977  * 3600 / 1000  = 4891L */
#define PLEVELDIV 4891L // to convert the sum into mAh divide by this value, ACS715
#define PSENSORNULL 102 // for I=0 A my sensor gives 102 * 4.9 mV = 0.5 V for ACS715
#define PINT2mA 37 // for telemetry display: one integer step on arduino analog translates to mA, ACS715 1000 / 133 * 4.9

Reliability

List of pages in this category:

-- RudolfReuter 2011-10-14 04:11:24


Go back to CategoryQuadrocopter or FrontPage ; KontaktEmail (ContactEmail)

QuadrocopterDrive (last edited 2014-12-03 18:22:51 by RudolfReuter)