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Pumpkin drop event

How manual is NAZA flightmode "Manual".

#1
Hi.

When the NAZA flight controller is placed into "Manual" flight mode, I have been wondering what flight control characteristics are still under ANY degree of automation by the flight controller.

My understanding is that NAZA will use its compass to maintain heading whilst in "Manual". However, roll, pitch and altitude are not assisted. In this respect, I have been of the understanding that the flight controller is behaving as a mixer with no pilot assistance (other than heading), translating transmitter stick-movements into various actions executed by the multi-rotor by changing the speed of the motors.

My questions are...
1) Am I blowing smoke out of the top of my head? ...If so, can someone correct me please.
2) How manual is manual?... In manual, is the flight controller doing any kind of other flight automation tasks other than being a glorified motor mixer?

Thanks in advance for your input.

Kind regards.
 
#2
1) My understanding is that manual mode means the copter is in rate mode and there is gyro stabilization only - the pitch/roll/yaw stick positions are proportional to the RATE of pitch/roll/yaw, as opposed to ANGLE. The gryos provide correction for deviation in rates - also known as flybarless stabilization. I don't think the compass is used, since the yaw gyro takes care of maintaining heading in this case. Throttle stick is directly proportional to throttle as opposed to altitude.

2) Manual mode is not totally manual - it is also known as rate/acro/agility modes. You can do this experiment: hold onto the copter with your hand and spin up the throttle (staying away from the spinning blades), leave the sticks in neutral position. While holding on to the copter physically roll/pitch/yaw it with your hand, you should be able to hear the motor changing speeds to compensate. That's because when the sticks are in neutral, the copter wants to maintain zero pitch/roll/yaw rate. Your shoved introduced a impulsive change in rates, the gyros sense that and tells motors to correct.

http://wiki.dji.com/en/index.php/Control_Mode
 
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#4
I ask this question because I have read the DJI NAZA manual. I am hoping to hear from someone with a very good technical understanding of flight controller functionality.

Many years ago (before the days of flight controllers and gyros) I used to fly helicopters, so learning to fly was done at the school of "hard knocks" aka lots of crashes. If you disregard maintaining heading and torque compensation, when flying with NAZA in manual mode, the multi-rotor behaves very much like an unassisted helicopter (it wants to trim your eyebrows). It requires constant control input to keep the aircraft stable, in one spot at a consistent altitude; and therefore hands-off flight doesn't really happen in manual (unless you want to crash). This is not to be confused with "attitude" ("atti.") mode, which in NAZA speak is assisted stable flight without GPS hold.

Even though constant input is required to maintain position of the multi-rotor's position in manual, I am curious to find out if the flight controller is still doing something to dampen the instability, or is accounting for other factors which make it behave more like a helicopter. Or, is the flight controller really doing nothing with the sensory input data.

Thanks and regards.
 
#5
Yes, in manual mode it requires constant input, but that does not mean it's completely manual. The flight controller is still compensating for the rate of roll/pitch/yaw, but not for angle. You can try the experiment I mentioned to see what I mean.

However, there is a key difference between the compensation in rate and angle mode. In rate mode, with neutral sticks, the compensation only happens while the copter is rotating - e.g. it wants to keep zero rate of rotation, compensation stops as soon as you stop rotating the copter. In angle mode, the copter will try to compensate as long as it is still "tilted" - it wants to keep zero pitch/roll/yaw.