The digital revolution at the end of the last century gave a powerful impetus to rapid development in almost all segments of our life. Of course, robotics has become one of the main directions. But this process is always accompanied by a huge number of new terms and concepts. As a result, they often provoke confusion, the elimination of which requires at least a simplified classification.
Probably the term drone was one of the first in robotics. But it has several meanings. In particular, drone is a male bee, from an unfertilized egg or a fertile male ant (animals). In science, it was originally used to refer to any robot. Strictly speaking, a robot vacuum can also be classified as a drone. Of course, any UAV (unmanned aerial vehicle) is also a drone. Ultimately, the rapid growth in their popularity has made the drone synonymous with all UAVs.
In turn, all UAVs are subdivided into multicopters (multirotor) with up to 8 rotors on the platform, and rotorcraft with a single rotor system.
In addition, the UAVs list includes fixed wing devices.
But the multicopter certainly dominates.
Classification
The multicopter is technically complex and has a lot of specs that directly affect its capabilities and price. Therefore, the choice of the optimal model significantly depends on the area of its application. With a good imagination, the user can come up with a very long list of its uses. But more often, today it includes:
– shooting (hiking, sports, boat trips, etc);
– area reconnaissance;
– hunting;
– search;
– guard;
– delivery drone;
– entertainment;
– drone racing.
By size, quadcopters are divided into mini, mid and big. The diameter of mini drone varies from a few centimeters to 20 centimeters.
They are inexpensive, have good maneuverability and are great for training in an apartment. But outdoors its power is insufficient to overcome even weak winds.
Expensive big drones are designed for professional tasks like filming movies. The flight altitude of some models reaches several kilometers.
Mid drones are great for most purposes and are the most popular. Usually their diameter varies in the range of 12-20 inches (30-50 sm). In addition, some modern models have a foldable design.
Any UAV contains three main components, including:
– arms for placing components;
– propellers to provide lift;
– motors for rotating propellers.
In the most popular quadcopters, opposing propellers are paired rotate clockwise and counterclockwise. At the same time, all the propellers are fixed pitch, providing the thrust in the same direction.
Rotors and propellers
These are the main specs that directly affect the performance, power consumption, etc of the model.
By the rotors number, modern multicopters are subdivided into tricopters, quadcopter, pentacopters, etc. The modern market offers all types of drones in abundance.
But a stable camera position in windy conditions requires three or more propellers. Therefore, tricopters, quadcopters, hexacopters and octocopters are the most popular. Wherein, quadcopters with 4 propellers dominate due to the most optimal price / performance ratio for most tasks.
Moreover, the name of these drones has become a household name. However, this situation is quite common. For example, in the last century, many consumers in Europe and Canada have used the names Hoover and Frigidaire for all vacuums and refrigerators due to their absolute dominance in these markets. A similar confusion arises with multicopters. Sometimes a tricopter or hexacopter is mistakenly called a quadcopter. Of course, the correct name depends on the number of rotors. Therefore, all quadcopters are multicopters and drones, but not all drones and multicopters are quadcopters.
The cheapest tricopters have three motors at the ends of a Y-frame. Unfortunately, they provide a small payload weight and their flight is unstable. Failure of even one motor causes an instant fall to the ground. Some companies offer tricopters with six motors stacked two on top of each other.
This design increases lift but does not solve the stability problem.
Hexacopters and octocopters usually use an H-shaped or another symmetrical frame to accommodate six or eight motors.
They increase payload weight and fly even if one engine breaks down. But large size, high price and high power consumption are their main cons.
Motor and propeller shape
Modern UAVs use brushed DC motors or BLDC (Brushless Direct Current Motor) motors.
BLDC is also sometimes called PMSM (Permanent Magnet Synchronous Motor). Each of the types has pros & cons. In particular, BLDCs drones are more powerful, significantly more durable, do not require cleaning after each flight, but they are significantly more expensive. But in recent years, manufacturers have been able to significantly reduce their cost. Therefore, today their popularity is growing rapidly.
The motor type is easily identified by the number of wires. In particular, brushed DC motors only use two wires (ground and phase). BLDC has a third wire to connect to the electronic speed control (ESC) module.
The shape, size and propeller inclination directly affect the flight height. Of course, they are selected taking into account the specs of all components. For example, the optimal propeller size for a mid-sized quadcopter ranges from 8-11″.
In addition, its shape affects battery consumption. For example, the sharp edges of the normal (N) propeller reduce thrust and power consumption, and bullnose propeller provides maximum thrust, but increases energy consumption.
Usually modern mid-budget and premium models use propellers made of durable and wear-resistant composite materials. But propellers for budget models are often made of cheaper plastic.
Control
Quadrocopters are controlled using a radio remote control or via Wi-Fi with a phone or tablet. In the second case, devices are synchronized via Wi-Fi, and control is carried out using a simple interface and touchmove. The Wi-Fi pros:
– convenient control of the height and speed;
– broadcasting video from the camera in real time;
– instant photo up to several fps by pressing one button;
– display of all current specs.
The short range of Wi-Fi is its only but significant drawback.
The range of the radio remote control reaches several kilometers. Today companies offer a variety of models with nearly identical placement of controls. For example, the left stick of the popular PowerVision Standard Controller for PowerEgg adjusts the flight altitude, while the right stick provides horizontal turns.
Other buttons adjust speed, flight stabilization, etc. But, of course, any method of flight control requires at least minimal preliminary skills. However, they are quickly acquired after several training flights at minimum speed.
Many modern models support first-person view (FPV), also known as remote-person view (RPV), or simply video piloting. In 2008 FPV has revolutionized the radio control hobby. In fact, it completely mimics the flight control from the onboard, providing a keen sense of flight enjoyment. In this case, the UAV is controlled with an onboard camera, which transmits video from onboard VTX via antenna to FPV goggles or a display.
More expensive professional models can use a pan-and-tilt gimbaled camera, which is controlled by a gyroscope sensor in the pilot’s goggles and with dual onboard cameras, providing a stereoscopic view.
Quadcopter with FPV can shoot high quality video. Of course, screen displays with FPV systems greatly simplify flight control, increasing its safety.
Other
Companies offer models with or without a camera. As a rule, modern mid-budget quadcopters come with 10-14MP cameras, which provide shooting with a fairly high resolution and color rendering.
Main specs:
– Wi-Fi support;
– protective case;
– water resistance;
– resolution, viewing angle, contrast and runtime.
Mini models often come with a 2MP camera.
But many users prefer non-camera models. They self-install popular GoPro cameras or other action cameras on them.
But the camera weight reduces the payload weight of the drone.
The batteries of a modern middron provide approximately 15-25 minutes of flight. For example, the popular DJI Spark Alpine White and DJI Mavic Air Flame Red fly without wind for 16 minutes (2 km) and 21 minutes (10 km).
Modern drones sometimes have case protection. But propeller protection is more popular.
Many models support the flight path programming with flight points. The autopilot is activated at launch or during flight. In this mode, the drone automatically adjusts flight altitude and stability, controls vibration and scans the space in front of it.
Home switch activates the return of the quadcopter to the launch site in automatic mode. This feature is mandatory when flying long distances. The drones fly in this mode on the height of the mode activation. But increasing the altitude beforehand will make it easier to fly in the event of high obstacles on the return route. As a rule, the return error does not exceed one meter.
The package also has a nuance. In particular, RTF (ready to fly) on the packaging corresponds to the presence of all the necessary accessories for the flight. The absence of this emblem corresponds to the need to purchase some accessories.
Conclusion
As known, in 2016 FAA (Federal Aviation Administration) has allowed micro UAVs to fly over cities. As per new guidelines, drones weighing up to 250 grams can fly without restrictions. Drones from four to five pounds cannot descend below twenty feet above people. Of course, the new rules have significantly expanded the capabilities of drones.
In addition, company efforts and competition have transformed drones from an expensive hobby into great and affordable entertainment. Today the market already offers mid-budget models for several hundred dollars. At the same time, drones with digital FPV system provide the brightest emotions, allowing many to realize their dreams of flying in the sky.
Moreover, these devices open up tremendous additional possibilities, including shooting, area reconnaissance, search, guard, delivery, etc. As a result, quadcopters quickly became one of the fastest growing segments of consumer electronics.
Of course, the huge offer slightly complicates the selection of the optimal model. But today the Internet offers various top lists, simplifying this process. After spending a little time, the user can easily choose the best drone depending on their budget. In addition, the model functionality is highly dependent on supported intelligent flight modes.
This video introduces the new DJI Digital FPV System.
