How Drones Work ?
How Drones Work – Drones have evolved over the years and become perfect flying machines
Why are drones designed the way they are today?
Why are they so efficient at moving so swiftly?
In this post, we’ll learn About the drone’s mechanical design aspects along with its electronics.
- And even Satellite Technology
So, let’s start with the most basic drone design and work our way up to the most advanced drone design.
A single propeller design
One propeller drones provide enough lift force to keep the drone hovering in the air, but there is no way to control it; it can only go vertical and come down. Another issue is that the drone’s body will continue to rotate in the opposite direction of the propeller due to Newton’s third law of motion. As you can see, the motor stator provides the appropriate torque to the rotor component, which implies that the rotor should return an equal amount of torque to the stator because the stator is fixed to the drone body. This reaction torque will cause the drone to spin in an unwanted manner.
Why not use two propellers instead? This is certainly a possibility, and a company called zero – zero robotics has made a serious effort to develop such a drone. The fewer propellers the drone has, the less energy it consumes and the longer it can stay in the air. However, manipulating the drone to fly at high speeds and take sharp quick turns requires a higher degree of control accuracy and stability.
Let’s hope that, with advances in control algorithms, two propeller drones can one day attain good stability.
Two and Three propeller designs
As you can see, the blades of two propeller types rotate in the opposite direction, cancelling the motor’s reaction torque and preventing unwanted body spin. The biggest problem with these types of drones is the motor’s reaction torque and gyroscopic precision; both concerns add unneeded complexity to the design and algorithms.
Four Propeller Drones
The four propeller drones or quadcopters in the next variation usually have a h shape or an x shape now let’s see how the quadcopters do the maneuvers by understanding the interesting force dynamics of them to achieve hovering the operator only has to make sure that the drone’s weight is exactly balanced by the thrust produced by the propellers.
The magnificent airfoil shape used by the propellers to generate lift force can be seen here. To achieve forward motion, the front propeller speed is lowered while the back propellers speed up, resulting in pitch motion.
Now, let’s make all of the force values the same by making the propeller speeds the same. Assume you’ve balanced the vertical component of the resultant propeller forces with the weight of the drone, but there’s still an unbalanced horizontal force causing the drone to move forward. A similar technique is used to enforce a drone’s roll movement. The yaw motion of a quadcopter is accomplished in a unique method.
To avoid such undesired spin in quadcopter drones, we learnt about the motor’s reaction torque and its effect on the drone at the beginning of this post. When one diagonal pair is spun in the opposite direction of the other pair, the response torque is fully cancelled.
If you want to yaw or spin the drone, all you have to do is make sure that these response torques don’t cancel out, which you can easily do by lowering the speed of one diagonal pair (reaction torque is proportional to propeller speed).
Eventually, a net response torque will occur, and the drone will be able to achieve the ah motion. Quadcopter drones are the most stable, with the capacity to go at high speeds and turn sharply. They are utilized in practically every industry.
Now let’s look at the drone’s brain. If a drone is hit by a strong gust of wind, the operator must regulate and modify each propeller’s speed and rotation direction in less than a second, or the drone would crash. This is a challenging circumstance for a person to operate by hand. In these situations, the drone’s most critical component, the flight controller, comes to the rescue.
The flight controller can be thought of as a tiny intelligent pilot sitting inside the drone, guiding it through any difficult situations. It allows the operator to operate the drone with simple controls such as up, forward, and yaw, making it as simple as playing a video game. To achieve this, the flight controller obviously requires a lot of input signals from various sensors.
Welcome to the interesting world of drone sensors
You might be astonished to learn that most of the sensors in a modern drone are around the size of an ant and that such tiny super-accurate sensors are made by ants. Microscale devices with genuine moving parts are used in mems technology. Accelerometers, gyroscope sensors, and magnetometers are the most essential sensors in this group. These three sensors are combined in the imu inertial measurement unit.
The IMU is the king of drone sensors, measuring acceleration and rotation in this accelerometer mems sensor as the drone experiences a forced movement occurs between the plates the two plates placed next to each other have a capacitance when the distance between the plates varies so does the capacitance the variation in capacitance can easily be converted into electrical signals and fed to the condenser
When we include gyroscopes in the unit along with force values, we’ll need a three-axis accelerometer to record rotations in different planes. The drone’s altitude is determined using a mems-based barometer sensor.
Now the flight controller or processor should make proper use of all the signals collected by these sensors in order to make correct judgments, but how can we ensure that the signals produced by these sensors are precise enough? Noise, for example, can impact a sensor’s accuracy. The mechanical vibrations of the drone propellers, as well as magnetic interference, are some of the causes of noise. To circumvent this problem, contemporary drones employ a method known as sensor fusion.
For example – A GPS sensor and an imu can provide basic altitude information for this drone, but we can improve the accuracy of this measurement by incorporating radar technology into it. This is sensor fusion, where different sensors work together to produce more accurate measurements. With these accurate signals, we can move on to the drone’s decision-making system, which includes the control system. Control logic is an algorithm that further lowers error and makes judgments. The Kalman filter is one such algorithm.
The KF algorithm reads past and present data to determine the state of the drone and employs its logic for GPS navigation, driving back home, and other similar cases, or in this case, stabilizing the drone after the disastrous effect of winds. Eventually, the same KF algorithm fed into the processor with logic gates and transistors, among other things, makes smart decisions to control the speeds of the BLDC motors.
Yes, the quadcopter drone can face any demanding environment simply by intelligently adjusting the speeds of the four BLDC motors.
DJI is currently one of the leading businesses in the consumer drone market, employing innovative flight control algorithms such as dual Imus for increased dependability and vibration dampening systems to reduce sensor output mistakes. In comparison to DJI, firms like Parrot, Autel, and Unique don’t have as much marketing consumer UAV drones. These drones lack refinement and fitness.
We already observed how the Kalman filter algorithm guarantees the drone has the stable and joyful flight power required by these BLDC motors when we looked at DJI’s drone. A lithium-ion battery powers the drone’s electronic circuits, antennae, and sensors. The drone receives the control signal from the operator via conventional radio frequency technology, with a range of one to two kilometers for a consumer drone.
Now an interesting question
What if the drone accidentally travels out of this communication range?
Modern drones employ GPS and tower-based internet technology to locate missing drones. The operator has already specified the home position when starting the drone with the help of GPS, so the lost drone may safely return home. We hope you enjoyed decoding the whole drone operating system. see you in the next post before you leave don’t forget to share this post with your friends, thank you.