Learn how electronic gadgets work with cainiao

I saw a video a few days ago. I think the four-axis flying machine is very good. I want to study it and prepare for a play. Everything has to begin with the basics. First, I learned the working principle of the next four axes, which is more convenient for future development. The following excerpt is a good article that combines graphics to make it easy to understand.

Let's take a look at a four-axis aerial chart.

In the form of quad-rotor aircraft structure, motor 1 and motor 3 rotate clockwise at the same time, motor 2 and motor 4, so when the aircraft balance flight, the gyro effect and Aerodynamic Torque effect are both offset. Compared with traditional helicopters, a quad-rotor aircraft has the following advantages: the anti-torque applied by each rotor to the fuselage is opposite to the rotation direction of the rotor, so when the motor 1 and 3 rotate counterclockwise, the clockwise rotation of motor 2 and motor 4 balances the anti-torque of the rotor to the fuselage. A quad-rotor aircraft has six degrees of freedom in space (moving and rotating along the three axes respectively). The control of these six degrees of freedom can be achieved by adjusting the rotation speed of different motors. The basic motion states are:

(1) vertical motion;

(2) pitch motion;

(3) Rolling;

(4) Yaw Motion;

(5) front and back movements;

(6) lateral motion.

In the figure, the motor 1 and 3 rotate clockwise, and the motor 2 and 4 rotate clockwise. The forward motion is called forward motion, the arrow above the motion plane of the rotor indicates that the motor speed is increased, and below it indicates that the motor speed is decreased.

 

(1) vertical motion: vertical motion is relatively easy. As shown in the figure, because two pairs of motors are opposite to each other, they can balance their anti-torque on the fuselage. When the output power of four motors is increased at the same time, the increase of rotor speed increases the overall tension, when the total tension is sufficient to overcome the weight of the whole machine, the quad-rotor aircraft rises vertically from the ground. On the contrary, the output power of the four motors is reduced at the same time, and the quad-rotor aircraft drops vertically until the balance is reached, vertical Motion along the Z axis is realized. When the external disturbance volume is zero, when the lift produced by the rotor is equal to the weight of the aircraft, the aircraft remains in the hovering state. It is critical to ensure the simultaneous increase or decrease of the four rotor speed.

(2) pitching motion: In Figure (B), the rotation speed of motor 1 increases, the rotation speed of motor 3 decreases, and the rotation speed of motor 2 and motor 4 remains unchanged. In order not to change the overall torque and total tension of a quad-rotor aircraft due to the change of the rotor speed, the variable of the rotation speed of rotor 1 and rotor 3 should be the same. Due to the increase of the lift of rotor 1, the lift of rotor 3 is decreased, and the unbalanced torque generated allows the fuselage to rotate around the Y axis (direction). Similarly, when the speed of motor 1 is decreased, when the rotation speed of motor 3 increases, the body rotates around the Y axis to the other direction to realize the aerial movement.

 

 

(3) rolling movement: the same principle as Figure B. In Figure C, the rotation speed of motor 2 and motor 4 is changed to keep the rotation speed of motor 1 and motor 3 unchanged, it allows the fuselage to rotate around the X axis (forward and backward) to achieve rolling of the aircraft.

(4) Yaw Motion: the Yaw Motion of a quad-rotor aircraft can be achieved through the anti-torque produced by the rotor. In the rotor rotation process, the opposite anti-torque will be formed due to the air resistance. In order to overcome the influence of the anti-torque, two of the four rotor can be turned forward and two reversed, in addition, each rotor rotates in the same direction in the next year on the diagonal line. The anti-torque is related to the rotor speed. When the four motors rotate at the same speed, the anti-torque generated by the four rotor is balanced with each other, and the four rotor aircraft do not rotate; when the speed of the four motors is not completely the same, the unbalanced anti-torque will cause the four-rotor aircraft to rotate. In Figure D, when the speed of motor 1 and motor 3 increases and the speed of motor 2 and motor 4 decreases, the anti-torque of rotor 1 and rotor 3 is greater than the anti-torque of rotor 2 and rotor 4, and the body rotates around the Z axis with the surplus anti-torque, achieve the yaw movement of the aircraft. The steering is opposite to the steering of motor 1 and motor 3.

 

(5) front-and-back motion: to realize the movement of an aircraft before, after, and left in the plane, a certain amount of force must be applied to the aircraft in the plane. In Figure E, increase the motor speed by 3 to increase the tension, reduce the motor speed by 1, and reduce the tension. At the same time, the rotation speed of the other two motors remains unchanged, and the anti-torque should still be balanced. According to the theory in Figure B, the aircraft first skews to a certain extent, so that the rotor tension generates a horizontal component. Therefore, the aircraft can be moved forward. Backward Flight is the opposite of forward flight. Of course, in Figure B C, the aircraft produces horizontal motion along the X and Y axes while generating the pitch and tumble motion.

(6) tendency motion: In Figure F, due to the symmetric structure, the tendency to flight works exactly the same as the movement before and after.

In general, the speed of the four motors is controlled. Then, the four axes can be moved by increasing the speed and slowing down accordingly.

 

 

There are various combinations of motor, battery and slurry below:

Battery:

What is a 1 s battery, 2 S battery, and 3 s battery?

1 s: lithium battery 1 block 3.7 v full is 4.2 V

2 S: Two lithium batteries are connected in series to 7.4 V

3 S: three lithium batteries are connected in series with 11.1 v

S stands for concatenation, and P stands for concatenation. 3 S represents three batteries connected in series, 3 P represents three batteries connected.

Battery discharge capacity. The maximum continuous current is: Capacity x discharge C

For example: 1500ma, 10C, the maximum continuous current is = 1.5x10 = 15

If the battery has been operating for more than 15 hours, the battery life will be shorter, and the battery voltage may be 4.15-4.20, the minimum voltage after use is over 3.7 for a single chip (remember not to put it over), and the retention voltage for long-term use is preferably 3.9.

 

Motor:

KV value of the motor: motor speed (no-load) = kV value x voltage;

For example, the speed (no-load) of a kv1000 motor at 10 V is 10000 RPM.

 

The higher the kV value of the motor, the smaller the torque provided. Therefore, the kV value is closely related to the slurry size. The following describes the slurry configuration experience:

Pulp:

1060 slurry, 10 indicates that the length of the diameter is 10 inch, 60 indicates the slurry angle (pitch ).

The first two digits indicate the diameter, and the last two digits indicate the pitch.

 

Combination:

The General Motor and slurry are configured as follows:

3 S battery; KV900-1000 motor with 1060 or 1047 pulp, 9-inch pulp can also

KV1200-1400 with 9050 (9-inch pulp) to 8*6 Pulp

About 7-6-inch KV1600-1800 Pulp

5-inch pulp around KV2200-2800

About 4530 of KV3000-3500 Pulp

 

2 S battery; about 9050 slurry for KV1300-1500

About 7060 slurry for kv1800

5x3 slurry for KV2500-3000

About 4530 slurry for KV3200-4000

 

The relationship between slurry size and current: the higher the slurry is, the higher the efficiency of generating thrust.

For example, with a 3 s battery, the current is also 10 Security (hypothesis)

The thrust produced by kv1000 with 1060 slurry and kv3000 with 4530 slurry is twice that of the latter.

 

Relationship between models and motors and pulp:

Generally speaking, the larger the slurry size, the greater the anti-torque produced by the aircraft. Therefore, the slurry size has a certain relationship with the wingspan size of the machine, but the slurry and motor also have the relationship described above.

For example, if 1060 slurry is used, the wingspan of the machine must be more than 80CM. Otherwise, the phone may easily cause reverse torsion; for example, if you use an 8*6 slurry wing, it will be more than 60.

For another example, if you want to use 4530 slurry for a wingspan of more than 1 meters, is it true? Yes, but the plane will consume a lot of power when it is flying. Because of the great resistance of the wingspan flight, the thrust produced by 4530 slurry is relatively small (the relationship between the above slurry size and current is described ).