Drone in Flight How They Work
Gyroscopes, Sensors and Computerized Positioning Systems are Behind the Magic
By Michael Lagapa
Whether they're capturing video from above or buzzing around an open field, there's no doubt that drones are becoming an increasingly popular gadget. After some practice, they're relatively easy to fly and maneuver and they can be somewhat inexpensive, not to mention entertaining to watch as they whiz around.
Quadcopter drones like those at the University of Pennsylvania's GRASP Lab form swarms like bustling bees and perform precise maneuvers that may look effortless, but the work going on beyond the controller is incredibly complicated.
The technology that drones are equipped with is a feat to be admired all on its own – gyroscopes, compact high-torque motors, motion sensors, batteries, and other bits of hardware are compressed into a package light enough to keep the drone hovering.
Once the drone is airborne, gyroscopes and sensors relay data to computers that use algorithms to make adjustments to the positioning of the drone. This keeps the drone balanced and hovering consistently and micromanages the varying rotor speeds that drones rely on in order to turn, roll, or move forward, backward, or vertically. Computer algorithms also assist the drone user in slowing the drone’s descent. This is in attempt to avoid the vortex ring state – an event where the drone's propellers descend too quickly and are caught up with irregular air circulation, causing the drone to lose lift and fall. While the drone pilot can control where and when the drone moves, the computer algorithms are doing a lot of heavy lifting in order to keep the drone stable.
A Closer Look at What's Under the Cover
So what exactly are all of those parts inside the drone? How do they work together to keep the drone flying?
A gyroscope measures the rate of rotation and helps keep the drone balanced. Gyroscopes are devices that consist of a mounted wheel that spins on an axis that is free to move in any direction. They're used to provide stability or maintain a reference direction.
A drone also has four high-torque motors powering each of the four propellers. These motors are usually brushless.
Motion sensors are an important piece of the drone puzzle. Altimeters communicate with the drone to let it know its altitude. These chips help the drone make necessary adjustments to keep it aloft.
A computer positioning system helps them maneuver. A programmer inputs the algorithms for positioning and the speed the rotors need to be moving; cameras track the drone by reflecting light off of its markers. This gives the computer an idea of where the drone is located. It's capable of pinpointing a drone's position to a millimeter.
As a result, the drone can flawlessly perform acrobatic movements and launch through tight spaces without error. If the positioning system is applied to several drones simultaneously, each drone can be set to a specific position and together, the drones can create a formation. The programmer must designate a center point for the drones to move around, so that individual drones move as a single unit and do not deviate from formation.
Drones typically use Lithium Polymer, or LiPo batteries. LiPo batteries are the power choice most favored by drone manufacturers since they are light weight and carry a maximized charge capacity and power.
Spinning In the Right Direction: Drone Movement
There are four primary movements that a drone employs and they're controlled by each of the four propellers. Propellers 1 and 4 move in clockwise, while propellers 2 and 3 move counterclockwise.
Yaw is the clockwise or counterclockwise spin of a drone. In order for the drone to employ yaw to rotate left, the number 1 and 4 propellers move at normal speed, while the number 2 and 3 propellers move at high speed. To rotate right, propellers 1 and 4 move at high speed and propellers 2 and 3 move at normal speed.
Pitch describes the forward and backward movement of a drone. To move forward, propellers 1 and 2 move at normal speed, while propeller 3 moves and 4 move at high speed. To move backward, propellers 1 and 2 run at high speed while propellers 3 and 4 run at normal speed.
Roll is the rotation of the drone to bend left or bend right. In order to roll to the left propellers 1 and 3 run at normal speed while propellers 2 and 4 run at high speed. To roll to the right, propellers 1 and 3 instead run at high speed and propellers 2 and 4 run at normal speed.
Uplift/downfall are the acts of moving the drone up and down, raising or declining elevation. To rise up, all propellers move at high speed and to descend, all propellers move at normal speed.
Not Just for Show: Drone Applications
While the acrobatics that drones perform may look like fun and games, developing drones should be able to perform a wide variety of tasks. Since they're agile and capable of maneuvering in tight places, they could greatly assist search and rescue operations, especially in dangerous situations. Being able to follow a set path would be perfect for providing personal security by setting them to patrol rooms and corridors. The United States Military is also interested in making use of this technology, as the drones (not to be confused with their hefty predator drone cousins already in service) would be excellent for surveillance and reconnaissance operations, especially when tasked to locate and warn soldiers of improvised explosive devices (IEDs). Drones could also be armed with an array of biological weapons that would help confine armed conflicts solely to those that are targeted. This in turn, would help reduce civilian casualties and structural damage in war, although this is quite a controversial application.
As impressive as they are now, it's hard to comprehend that drones are still getting increasingly advanced every day. Behind the ambition and diligence of robotic engineers, don't be surprised if fully conscious and autonomous drones are flying overhead in the near future. For drone technology, the sky is truly the limit.
Don't forget to check out Jameco's selection of drones. While you're at it, watch Jameco's RC quadcopter review video.
Have you flown a drone? Write to us and share your story at [email protected].
Michael Lagapa was a summer intern at Jameco Electronics. He is entering his sophomore year at UC Santa Cruz, and is pursuing a degree in Computer Science. His hobbies include biking, swimming, martial arts, and staying up to date with the latest technology.