Basic knowledge of drones (structural)

Drone has become more familiar with the number of opportunities to see these days.In this series, we will explain the structure of the drone six times.The first one will focus on differences from helicopters.Helicopters and drones tend to be recognized as completely different.But that is not the case.The drone described in this paper refers to a so -called multicopter with multiple rotors (rotation wings).A wideified drone in aircraft refers to unmanned aircraft in any format.In this paper, we will use the term drone only for multicopters.

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1st: Difference between drone and helicopter

1.Helicopter structure

Helicopter controls the flight by controlling the inclination of the rota wings.A general helicopter will imagine something like Fig. 1.Typical structural portions include a large wings that stand out and the small feathers behind, and both rotate.The larger one is called the main rotor, and the smaller one is called a tail rotor.The main rotor has the role of rising and moving (promotion), and the tail rotor has a role in preventing the aircraft from being swung by the main rotor and the role of controlling the direction of the aircraft.

The reason why it is difficult to control the helicopter is the mechanical control structure.Figure 2 shows the rotor part that represents the mechanical complexity.This part controls the angle of the wings of the main rotor.The reason why it is so complicated is that the wings of the helicopter depend on the rotating position ...

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2.Drone structure

In the case of helicopters, the main rotor controls the movement by changing the inclination of the wings depending on the rotating position.Drone, on the other hand, is different from a helicopter, and controls the feathers.Figure 3 is a general drone.The type with four of these wings is called Quad Rotor -type multicopter.

Let's look at the structure of the rotor part, just like a helicopter.As shown in Fig. 4, it has a really simple structure.In the case of a drone, the structure is as simple as using multiple rotors to control by controlling the power of the direction you want to move or the rotor on the other side.The control of the force is performed only by controlling the motor speed.

however,...

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3.Comparison of helicopter and drone

Helicopters and drones fly using a rotor.Drones use multiple rotors to eliminate mechanical complexity.Rota provides lift and propulsion.Aircraft, such as helicopters and drones, are called rotating wings because they rotate their wings and fly.On the other hand, ordinary airplanes are called fixed wing machines.

The feature of a rotating wing is that it can be left in the spot by rotating the wings.By rotating, it creates a state where air is constantly hitting the wings, gaining the power to lift, that is, lift.In this regard, ...

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2nd: Drone components

Last time, I introduced the difference between drones and helicopters.This time, I will explain the components of the drone.As described last time, the structure of the drone is mechanically simpler than helicopters.On the other hand, drones can be said to be complicated about electrical and electronic structures because electronic control is frequently used.Therefore, we will explain the components of the basic four -rotor drone (quad copter) as an example.

1.Those that make up a drone

ドローンにはいくつか形状があります。図1に4枚ロータの構成要素を示します。1つのロータ（回転翼）は1つのモータで駆動され、モータはESC（スピードコントローラ）で駆動されます。仮に、これが6枚ロータのもの（ヘキサ・コプター）になった場合には、ESC +motor + ロータの組み合わせが6セット必要になります。

There is one important component that is not written in this figure.It is the aircraft itself, and in drones, it is often called a frame.The frame is equipped with all the components shown in the figure, and ...

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2.Outline of each element

Next, we will explain the six components of the drone: rotor, motor,Esc, various sensors, FC, and receiver.

・ロータ

Rota is a wing to gain lift and propulsion.Often connected to the motor.Depending on the aircraft, it may be connected via gear.The size of the rotor is determined by the weight of the drone and the required performance.In the past, radio controlled propellers were often diverted, but recently the number of drones exclusively has increased.

・モータ

The motor is the part that rotates the rotor, so to speak, the engine.DC (brush) motors, such as toiladicons, are sometimes used, while medium to large drones use a type of motor called brushless motor.This is a type of three -phase motor, an exchange motor, and is driven by a controlled signal.The motor must be applied to the rotor used.

・ESC

ESC (Electric Speed Controller) is an electronic circuit that drives the motor.It is used to control the power using a motor with an electric radio control and controls the rotation speed of the brushless motor.The drone controls the motor speed by the signal entered in theEsc to change the lift and thrust depending on the rotation speed.ESC controls a large current to drive the motor, the power of the drone.You need to selectEsc according to the motor request.The generalEsc uses the same type as the input signal used in the radio control.

・各種センサ

Various sensors are used to detect the posture, condition, position, etc. of the aircraft.A typical example is ...

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3rd: Drone frame

Last time, we introduced the components of the drone structure.This time, I will explain the drone frame.The frame is the aircraft consisting of a drone itself, which is equipped with various components.A frame means a frame in Japanese.The general drone has a shape with a motor or propeller on the frame.This section describes why drones have such a shape, and the shapes and characteristics of various frames.

1.Conditions required for frames

The basic condition of the frame is light and durable.What can be said in all of the flying things, including airplanes, is justice.There is nothing light to lift something in the air and do something.The requirement required for flying is, above all, lighter.Heavy objects mounted on the drone include motors and batteries.These are not lighter to some extent because the performance is determined by physical size and weight.Therefore, it is necessary to make the frame as light as possible.

However, if you try to make a drone frame as lightly as possible, you may break during the flight and crash.You can see that the flying frame is surprisingly powerful.The same is true for actual airplanes and helicopters, and if you do an unreasonable maneuvering with a light aircraft, it will still break.The problem is that the lighter is lost, and the aircraft cannot withstand its movements.In addition to lightness, you must clear the durable conditions.This balance is difficult, and if you try to make a strong aircraft, it will be too heavy, so it is necessary to reduce the strength of the last minute that will not break and do not do unreasonable maneuvering.

・使用される素材

...

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2.Difference depending on the shape

The drone frame is the shape of the drone itself.There are several types depending on the shape.Due to the difference in the shape of the frame, the drone configuration is classified into five categories: Quad Plus, Quad X type, Quad Hich type, Triecopter, and Baicopter.The round part is a rotor, and the arrow in the circle refers to the rotation direction of the rotor.The upper side of the figure is the direction of the drone travel.

・クワッド・プラス型

The Quad Plus type is a multicopter with four rotors in a+type when viewed from the top of the drone from above (Fig. 1).It was often adopted in the early days of multicopter.This shape is relatively easy to control because the position of the control is matched.On the other hand, when shooting with a camera, it is a style that is not very preferred now because a part of the frame and rotor will be reflected.

・クワッド・エックス型

The Quad X type is a multicopter with four rotors in the X type when viewed from the top of the drone aircraft (Fig. 2).It is adopted as the most common style.The feature is that there is a rotor on the left and right of the direction of travel.But isn't the recent drone not attached to the rotor like this?You may feel that.

・クワッド・エイチ型

クワッド・エイチ型は、...

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4th: What is a rotor?

Last time, we introduced various shapes and characteristics about the drone frame.This time, I will explain the rotor, one of the main parts of the drone.At first glance, Rota is just like a propeller, but is actually a drone wing itself and plays an important role in flight.The rotor of the rotating wing is an important part of gaining propulsion in addition to lift.

1.What is a rotor?

The rotor is the rotating part of the rotating wing, and plays a role in creating propulsion.In addition, the rotor is often called propeller in drones, and in accurate representation, it is a wing that rotates wings.The rotating wing aircraft is so central to be called ROTOR CRAFT in English.

Generally, the propeller is called a propeller (Propeller).For this reason, the screw of the ship is also called a propeller.In the case of an airplane, a propeller is used to produce lift using a fixed wing (Fixed Wing) and gain propulsion to move it forward.

So why do drones often call rotation wings as propellers?It is probably because the plane for airplane was diverted in the early days when multicopters were created.In the early days when multicopters or drones appeared, there were no spinning wings, so the rotor had a plane for airplane and the rotation of the airplane was used.For this reason, the name of a propeller may have been established.Even now, I often use propellers for airplanes for my own drones.

ロータ（プロペラ）に対するイメージは、風を送るファンのようなものと思われがちです。しかし、...

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2.Difference between shape and type

Various elements are determined in the rotor depending on the shape, rotation direction, diameter and pitch.In the case of hobby applications, propellers for airplane radio control are often diverted.

・ロータの形状と回転方向

The most commonly used drones are two or three wings, and the most commonly used feather is two.I don't see much more than that.

The most important point in a drone is to need two types of rotors according to the rotation direction.The drone rotor is determined whether it is right or left rotation depending on the mounting position (3rd).For this reason, it is necessary to prepare a rotor according to the rotation direction.Fig. 2 is an example of a two -piece rotor, the left turns left and the bottom is a right turn.The right and left indicate the rotation direction when viewed from above.The sticker on the rotor in the figure is called a rotor balancer and is for adjusting the subtle weight difference of the wings.Even if the two rotors are the same, the weight may make a delicate difference, so use a rotor balancer to adjust it.

The rotor shown in Fig. 2 is a type called "5030", with a diameter of 5 inches (12)..7cm), pitch 3 inches (7).62cm).In the case of a radio control propeller, the numerical value is used in this way.

・ロータの直径とピッチ

ロータの形状を決めるには羽の枚数だけでなく、...

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3.How to select a rotor

The method of selecting the rotor is determined by the size of the aircraft and the characteristics of the motor in the case of a self -made machine.However, choosing a rotor on a self -made machine is one of the difficult problems.First, when the size of the frame is determined, the motor that is suitable for the required power is determined.Once the motor is determined, the diameter and pitch of the suitable rotor are determined.When making a self -made machine, it is basically to select a suitable rotor by referring to the motor specifications written in the manual when purchasing a frame.

In the case of a manufacturer -made drone, the rotor uses parts from the same manufacturer to replace the rotor.There is no problem if a rotor is prepared as a genuine option.

ロータは、非常に壊れやすく、...

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5th: Driving system

Last time, I explained the rotor, the main part of the drone.This time, I will explain the drive system, which is an important part of the drone emerging and flying.The drive system is a system that conveys the output of the engine, basically consists of a motor and a part calledEsc that controls it.In drones, these two are the main components of the drive system.

1.motor

A motor is a general term for devices that convert electric energy into mechanical energy.Motors are classified as brushimoters and brushless motors (Fig. 1).For general drones, brushless motors are used.Brushless motor requires a driving circuit.

・ブラシモータ

The brushimotor is a motor with two lines and is used for models and small toy drones.An electrode called a brush and a rectifier called a community are provided inside the motor, and the two are mechanically switched to rotate the motor.The speed change is performed in a way called PWM (Pulse Width Modulation).

・ブラシレスモータ

ブラシレスモータは線が3本出ているモータで、専用の駆動回路を用いて回転させます。ブラシモータで必要なブラシと整流子などの機械的な接触部分を取り除いて整流回路を備えているため、エネルギー効率上優れています。信号によって回転方向を変えることも可能です。しかし、ドローンでは...

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2.Esc

ESC (Electronic Speed Controller) is a controller to rotate the motor and is used for brushless motor speed control on a radio control.OneEsc is used for one motor, and as shown in FIG. 4, a circuit to be controlled and a circuit that drive the motor is incorporated.The part where the three lines on the left are connected to the motor, and the rotation direction is determined in the order of this line.The one with three thin lines on the right is for control by connecting to the controller and the power (battery).The surface seen in the figure is a control circuit, and the back side is equipped with a power semiconductor that controls power.

一般的に制御信号はラジコン式で、ラジコンのサーボモータと同じ信号を用います。ドローンや飛行機ではモータの回転方向が通常1方向なので、入力された制御信号に応じて回転数が変わるESCが用いられます。一方、自動車ラジコンの場合にはモータを逆回転させる(バックする)必要があるため、...

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6th: Control system

Last time, I explained about the drone type.This is the last round.I will explain the control system that can be said to be the reason why drones are drones.With the development of the control system, the drone has become much easier to fly than at the beginning of the appearance, and it is also possible to automatically navigate with autonomous control.By improving the performance of the computer installed, more complicated processing can be performed on the aircraft.Introduces control systems that support the stable flight of drones, their key flight controllers, and various sensors.

1.Flight controller

Flight controllers (FC) are computers that perform various processes on the plane.This is the most important part of the internal structure of the drone (Fig. 1).In particular, the aircraft stabilization and autonomous navigation are automatically controlled.The flight controller at the beginning was focused on stabilizing the aircraft.This is because if you just fly, multi -copters only control the motor, so you can control the control compared to a physically complex helicopter.However, when trying to fly a stable flight, the control was difficult in human power.For this reason, some stable mechanism was needed.Even a helicopter, which is not easy to maneuver, could manage to control it by practicing.However, the control of the multicopter was even more difficult.

In order to realize stabilization, the gyro was initially installed.The gyro detects the angle speed (the angle rotated in one second).This is the most basic idea of stabilization.

現在のドローンでは、...

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2.Used sensor

Various sensors are used for flight controllers.Recently, image recognition using cameras is increasing.It can be said that the higher the type and number of the sensor, the more advanced control.Below are a typical sensor.

・ジャイロ、加速度センサ

Gyro detects angular speed, and acceleration sensor detects acceleration.These two are the main focus of the aircraft stabilization.It is sometimes called a 6 -axis sensor with a 3 -axis gyro+3 axis acceleration.

・距離センサ

The distance sensor is used to detect the distance from the ground when taking off and land, or to detect the height when hovering (stopped in the air).There are several methods for the distance sensor, and the optical formula (PSD: Position Sensitive Detector) and ultrasonic type (Fig. 2) are typical.In each case, the measurement distance is not so long, so it is used for distance measurement near the ground.

・高度センサ

Advanced sensors are used to measure the height of the aircraft flying.Generally, a pressure sensor that uses the lower height as the height rises is used.Since it can be used up to a relatively high altitude, it is also used to stabilize the top and bottom position at a high position.GPS can be used for altitude estimation, but not very accurate.For this reason, the pressure sensor and GPS may be used together.

・磁石（コンパス）

ここでいう磁石は、いわゆる方位磁石のことです。半導体式の磁気センサを用いることで、...

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