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?
Here we will explain the drone’s mechanical design aspects along with its electronics controller, sensors, intelligent algorithms, and even satellite technology.
Let’s start with the two propellers’ drones. This is a possibility and a company called zero robotics has made a serious attempt to develop such a drone. the fewer the number of propellers the less energy the drone will consume and the longer it can stay in the air.
However, the main issue is that manipulating the drone to fly at high speed and take sharp quick turns requires a higher degree of control accuracy and stability. let’s hope with the advancements in control algorithms, two propeller drones will achieve good stability one day. the two-blade propeller designs rotate in the opposite direction. This way the motor’s reaction torque gets canceled and the undesirable body spin can be avoided.
three propeller designs are very rarely used because the main issue with these types of drones is the motor’s reaction torque and gyroscopic precision. these issues create unnecessary complications in the design and the algorithms.
The next variation of four propeller drones or quadcopters usually has an H shape or an X shape. the quadcopters do the maneuvers by understanding the interesting force dynamics of them to achieve hovering the operator has to just make sure that the weight of the drone is exactly balanced by the thrust produced by the propellers. The propeller utilizes to generate lift force to achieve forward motion the front propeller speed is slowed down while the rear propeller speeds up.
This will cause pitch motion. now let’s make all the force values the same by making the propeller speeds the same. Here suppose you have balanced the vertical components of the resultant propeller forces with the weight of the drone. even after this, there is an unbalanced horizontal force that will make the drone move forward.
A similar technique is used to enforce a drone’s roll movements put simply this movement is carried out by creating an imbalanced lift force in the left and the right pair of propellers.
A quadcopter’s yaw motion is achieved in a unique way.
Suppose a drone is hit by a sudden gust of wind the operator has to control and readjust each propeller’s speed and rotation direction in less than a second otherwise the drone may crash.
This situation is difficult for a person to control by hand. these kinds of scenarios are where the most important part of the drone comes to the rescue of the flight controller.
the flight controller can be thought of as a tiny intelligent pilot sitting inside and navigating the drone through any difficult situations. It enables the operator to use simple controls like up, forward, yaw, etc making the drone operation as simple as a video game.
To achieve this result the flight controller obviously needs a lot of input signals from various sensors. The modern drone sensor is comparable to an ant to fabricate such tiny super-accurate sensors mems technology comes into play. They are microscale machines with actual moving parts.
The most important sensors in this group are accelerometers, gyroscope sensors, and magnetometers. These three sensors are placed together in the imu (inertial measurement unit). imu is the king of drone sensors. it measures acceleration and rotation. in this accelerometer, the 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 the capacitance varies too. the variation in capacitance can easily be converted into electrical signals and fed to the controller for calculations. to achieve acceleration in all three directions we will require a three-axis accelerometer.
when we include gyroscopes also in the unit along with the force values we can measure the rotations in different planes. a mems-based barometer sensor is used to determine the drone’s altitude.
now the flight controller or processor should make the right use of all the signals these sensors collect to make correct decisions. however, before going into the processor piece how can we make sure the signals sensors produce are accurate enough noise for instance can affect a sensor’s accuracy.
Some reasons for noise are defects interference by the mechanical vibrations of the drone propellers and magnetic interference. morden drones use a technique called sensor fusion to overcome this issue for example a GPS sensor along with the imu can provide basic altitude information for this drone. however, we can make this measurement super accurate if we integrate radar technology also into this.
This sensor fusion different sensors working together to produce more accurate measurements. with these accurate signals, we can get into the decision-making part of the drone the control system part. Which includes the control logic the control logic is the algorithm that reduces the error further and makes decisions. One such algorithm is the Kalman filter.
The kf algorithm read the past and present data to know the state of the drone and utilize its logic for GPS navigation driving back home and any other such cases or in this case stabilizing the drone after the disastrous effect of winds eventually the same kf algorithm fed in the processor having logic gates and transistors etc make smart decision to control speeds of bldc motors.
Yes just controlling the speed of the four bldc motors in a smart way the quadcopter drone can face any challenging environment. currently, a company called DJI is one of the leading companies in the consumer drone market.
They use advanced flight control algorithms dual Imus for more reliability and a vibration dampening system to reduce error in sensor output. Sophisticated algorithms are one of their keys to success. on the other hand, compared to DJI companies like parrot autel and unique don’t have as much marketing for consumer UAV drones.
These drones lack the refinement and fitness you get with dji’s drone. we already talk about the bldc motors by Kalman filter algorithm ensures the drone a stable and happy flight power required by these bldc motors electronic circuits antennas and sensors are supplies by a lithium-ion battery. the drone receives the control signal from the user using the common radio frequency technology the range of communication can be between one to two kilometers for a consumer’s drone. if the drone is missed then to get back morden drone makes use of GPS and tower-based internet technology together. the operator has already set the home location when starting the drone with the help of GPS. this way the lost drone swiftly gets back to its home location.