4

If you want to maximise efficiency, you go with two rotors: a main rotor, and a tail rotor. I.e. a traditional helicopter. With the common CCPM setup (Cyclic Collective Pitch Mixing), you have three servos controlling the main rotor. Together they can tilt it any direction and control the pitch on the blades. As you can imagine, this is mechanically ...


4

For a basic multicopter, in the absence of any other way to control yaw, orientation does matter. A quadrotor needs a balanced set of rotation directions so that it can easily control yaw direction, and at equilibrium, all propellers can rotate at the same speed. This is primarily because all rotors in a quadrotor are fixed (usually). The quadrotor can also ...


4

This has to do with the torque, or moment, the rotors induce on the body of the quadcopter/multirotor. If all of the rotors were to spin the same direction they would all induce a torque in the same direction causing the craft to yaw. Of course this is undesirable for many reasons. By spinning half of the rotors the opposite direction the torques are ...


4

A dualcopter, of the form you are talking about, can control all roll, pitch, yaw and it's altitude. To do so, it employs two rotors running in opposite directions to cancel any torque. This would give the copter the ability to control its altitude and yaw (by changing the relative speeds of both the rotors). For the rest, such a copter usually employs ...


4

Controlling a flying robot (or anything else) is a very complex subject (well, people are doing PhD on it..). I can recommend this free online course on the subject (I have taken it myself). It will give you a little taste of what it is.


3

The course suggested by @Eugene Sh is a good one to understand in depth the relevant details. If you have general idea about how an aircraft (fixed wing) operates it will be actually helpful to you. Refer Small Unmanned Aircraft:Theory and Practice by Randal Beard, one of the pioneers in aerial vehicle research and T.Mclain. This is about fixed wing aircraft,...


3

In process of selection of components for multirotor, one should start from motor as it is the driving component. Maximum current drawn by your motor is given by manufacture which is 15A. Now your ESC should have maximum current rating more than maximum current rating of motor. This is satisfied in your motor-ESC combination so your selection looks good. ...


3

First, you can look at Mikrokopter as an example of quad with centrally mounted ESCs. As for the various engineering reasons for ESC location, here is some rationale behind the two you mentioned 1) Interference/noise. Non-steady state current running through wire can induce current to flow in nearby conductors. Practically speaking, this means that if you ...


3

A quick google search yields this video of an RC dual copter that looks like it is able to control its pitch, roll and yaw: https://www.youtube.com/watch?v=_cwCHgmDbz0 Skip to 5:50 for the part where he actually flies it. As for quadcopters, there is a well known video circulating on the internet of a presentation given at a TED conference by Raffaello d'...


3

Ideally, when you raise the collective all the way up, all the ESCs put out their max power and the quadcopter goes straight up. Different ESCs will end up producing different maximum thrusts; and also will ramp up (and down) differently with sudden changes in control signal. As you probably already know, if one rotor of a multirotor vehicle has more (or ...


3

Wrapping your head around unit conversions in controllers is a pretty common problem, so don't think you're alone. If you're implementing your PID controller using floating point math, then you really don't have to worry: the gains that you assign for the proportional, integral, and derivative action will take care of the differing ranges for the inputs and ...


3

The best way to manage power redundancy for autonomous systems is a really interesting topic. There are two classes of power needed. Flight and processing. Often the power required for flight is much higher than what's needed for processing. Issue number 1 is that as soon as you introduce redundancy (2 batteries instead of 1) you incur a penalty of extra ...


3

practice In practice, every multicopter (including 6-propeller hexacopter and 4-propeller quadcopter) that I've seen so far has 4 degrees of freedom: pitch, roll, yaw, and climb. The minimum number of rigid rotors to get 4 degrees of freedom is 4 rotors. (Single-rotor helicopters have articulated blades and swashplates, which are more complicated than ...


2

I can say positively that 900Mhz china video transmitters can affect 2.4Ghz frequency range. I experienced this first hand and confirmed interference on my spectrum analyzer, it can cause harmonics on the 2.4Ghz but when the tx and rx are close it appears to have an affect on the noise floor too, using those low pass filter don't seem to help close range ...


2

Since your frame is about (220g + other parts' weight), you need to make sure that your 4 motors give you a combined thrust of atleast 100 g more than, just to get off the ground and maneuver. Anything greater than that is good. (Thurst Calculator). Just looking at the numbers, I think it should work out fine. You battery amps * burst C / constant C should ...


2

Tim Wescot is one of the most experienced experts ever in this forum especially in the PID controllers field. I recommend you to read his brilliant article here. We used discrete PID for our quadrotor control system. We are building a quadrotor right now and tested both continuous PID controller(What you are usually find in wikipedia or web searches) and ...


2

You can run a brushless DC motors backwards using a H-bridge. Basically you'll need to program your microcontroller/microprocessor onboard to flip the polarity of 2 of the wires of the bldc (a bldc has 3 wires, switching any 2 wires will reverse the spin)


2

Two approaches are possible: Combine the altitude (GPS or pressure) and vertical acceleration sensors' data to calculate a better geometric altitude, and tune your vertical controller using this feedback in your loop. Employ a stability augmentation loop for the z-acceleration (in body frame). In this case, if your vehicle swings, as shown on Jon's answer, ...


2

Seeking proficiency in C++ or in OOP in general would either have to be a result of obtaining the necessary knowledge in order to browse through the code-base of the flight controllers that you mentioned, or with the eventual goal that this is what you would use when implementing your own flight controller. The first thing is familiarizing yourself with the ...


2

You seem to be controlling the quadrotor's attitude (roll, pitch) to (0, 0) and not its position. What you are seeing is drift in position, which is inevitable if you do not control the quadrotor's position. You might still be able to reduce the amount of drift a little: Make sure that the center of gravity of your quadrotor is actually in the center. If ...


2

There are quite a few possible explanations for the instability, I'll try to list 'em: PID settings are off the mark. I'm not familiar with KK2.1.5 Multi-Rotor controller, but I'm sure there will be something to adjust the roll/pitch PIDs. Try tweaking them. Under-compensated integral error may be a possible culprit. Some issue with ESC calibration. Try ...


2

There's a lot of things that this could be. The transmitter could be faulty, and transmitting considerable power close enough to 2.4GHz to be directly interfering with the receiver. Yes, the receiver is spread-spectrum, but interference to such a receiver will generally raise its noise floor, which will reduce its range. The receiver could be faulty; it's ...


2

If I'm understanding you correctly, you are saying that the motors spin, but they don't spin fast enough to generate enough thrust to get the drone off the ground. It sounds to me, if this is the case, that you maybe haven't done the speed calibration for the electronic speed controllers (ESCs). Here is the Hobbywing page on calibration, if you are using ...


2

Firstly, you may be confusing ArduPilot/ArduCopter software with the ArduPilot Mega (APM) hardware platform. ArduPilot/ArduCopter is indeed a great piece of software and is still maintained. The ArduPilot Mega (APM) has been discontinued, and as such, has very limited support and development. Regardless of that, I looked into this whole issue, of which ...


2

Your own equations make a lot of assumptions about the problem you are trying to solve. They are sufficient to solve your problem, but will not work for certain conditions (z = 0 for instance). Euler angles are similar. A way describe orientation (we typically use orientation to mean all angles, not just pitch and roll as you are using here). Euler angles ...


2

I came across one paper that had a good description of this issue from Kristina Lerman and Aram Galstyan at University of Southern California entitled "Mathematical Model of Foraging in a Group of Robots: Effect of Interference"


1

The website that you have used seems to be down, however looking at the specs announced on banggood, it looks compatible. You would need some 8*4 props and a 3S battery, I'd advise getting a 3000mAh one that can handle full power (200W per motor so 800W total for a 12V*3Ah battery=>36Wh so that's 800/36=22C) so a 3S 3000mAh 25C constant LiPo would be perfect ...


1

Operating an ESC is practically the same as operating a servo. The main difference is that instead of the pulse width translating to a position on the servo, it translates to an output speed. The range of widths is identical with ~1000µs representing the lowest setting and ~2000µs representing full on. These values can sometimes go beyond (as overshoot), ...


1

Which piece is the robot? This is not a robotics question. I have to assume since you are asking a question that shows a lack of fundamental mechanical understanding, that for its intended use, precision is not a requirement. In that case, wrap the motor shaft with some tape until you have the tightness you are looking for. A more appropriate fix would ...


1

This would be a hack, but you could add a small amount of weight to it so the tick that makes the quad ascend slightly would now be the hover tick.


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