03 August 2017

Unmanned Aerial Vehicle - An Introduction

In this blog post, our Hardware Engineer Tanmay Chakraborty writes about Unmanned Aerial Vehicles (UAV). It represents an enormous market segment that spans IoT, emergency response and many more with promising growth for near future.

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INTRODUCTION

UAV- Unmanned Aerial Vehicles which is commonly termed as drones, is an aircraft which has no human pilot on board, it can be remotely controlled via a remote from a ground base station or may have autonomous algorithms for auto pilot. Historically UAVs were mostly used for military applications for missions that were too dangerous for humans to perform. In today’s world UAVs find a number of use cases military, civil, scientific, creative, business survey, agriculture, recreational and the list goes on. In fact civilian UAVs now vastly outnumber military UAVs With over a million sold by 2017, they have emerged as an early commercial application of autonomous applications.


HISTORY
Innovation in the field of UAVs first started as early as 1900. In 1916 an attempt to develop a powered UAV was taken up by A.M. Low. He developed a model “Aerial Target”. The first remote controlled aircraft was developed by model-air plane enthusiast Reginald Denny in 1935. During the world war II UAV development got a boost. Nazi Germany manufactured and used various UAVs during the war. In 1959, the U.S. Air Force began using the UAVs to protect their pilots from flying into hostile territories. With the improvement in technology in 1980s and 1990s the advancement in UAVs were encountered.

UAVs evolved as a possibility of cheap and capable flying machines, deployable without risk to aircrews. Initial uses were surveillance but soon they emerged as a tool for aerial photography.


CLASSIFICATION
UAVs can be broadly classified into six categories.
  • Target and decoy – These UAVs provide ground and aerial gunnery a target to be shot at.
  • Aerial Reconnaissance – providing battlefield intelligence to the intelligence bureau.
  • Aerial Combat – These UAVs provide attack capability for missions that have high-risk factor.
  • Logistics – These types of UAVs are meant for delivering cargoes.
  • Scientific Research and Development – improve UAV technologies for the future of drones.
  • Civil and commercial UAVs – agriculture, aerial photography, data collection, construction, surveillance.

GENERAL COMPONENTS OF AN UAV
Generally, the UAVs consists of the following basic components.
  • Chassis – The body of the UAV. Initially the chassis were designed like the air crafts but with introduction to quad rotors, octo rotors chassis design changed too.
  • Sensors – To achieve autonomy a number of sensors have been placed in an UAV. Most basic and important sensors being gyroscope and accelerometer, barometer, telemetry, GPS, magnetometer, LIDAR etc.
  • Communication – For controlling an UAV remotely communication between the UAV and the base station is the most important thing. Radio Frequency is widely used for such purposes. Nevertheless, wireless technologies like Wi-Fi, LTE are also in testing phase.
  • Data Collection Unit – This unit consists of cameras. They are the eyes of the UAV. They can be used for aerial photography or to have a track of where the UAV is heading. With improvements in the field of computer vision they are now being used for obstacle avoidance systems for the UAV.
  • Power Supply unit – Most UAVs are powered by Li-Po cells.
  • Flight Controller Unit – This unit is the brain of the UAV. It consists of a system on chip board with a fast microprocessor. Capable enough to process the Inertial measurement and data processing in real time.
  • Actuators – The actuators involve a digital Electronic Speed Controller (ESC) connected to a brushed DC motor/engine. The propellers are connected to the motors. The specification of the motors and propellers change according to the job the UAV needs to function. For lifting a high payload high torque motors are used with longer propellers.


SWARMS
Improvement in technology had a great effect in almost every field. One of the most interesting technology in the field of aerial robotics is “Swarms of Drones”. Swarm as the name suggest, it consists of a number of drones, coordinated together to perform a given task. Each drone can sense its surroundings and react to its surroundings according to the stimulus. Swarms are a biological inspiration taken from swarms of bees. One of the best example is the World Record created by INTEL where they used around 500 quad copters to form patterns in the sky.


AUTONOMY
The autonomous features that are common among the present UAVs are listed below.
  • Self-level function – This is a feature that helps the UAV to maintain a particular altitude on the pitch and roll axis.
  • Altitude hold feature - The UAV maintains its altitude using barometric or ground sensors.
  • Hover - Keep the pitch and roll level, stable the yaw heading and altitude while maintaining position using GPS or inertial measurement unit.
  • Headless mode - Pitch is controlled relative to the position of the controller rather than relative to the vehicle's axes.
  • Care-free mode - Automatic control for roll and yaw while moving horizontally.
  • Failsafe for drones - Automatic landing or return-to-home upon loss of control signal from the base station.
  • Return-to-base - Fly back to the point from where the drone took off.
  • Follow-me function - Maintain relative position to a moving controller or other object using GPS, image recognition or homing beacon.
  • GPS waypoint navigation - Using GPS to navigate to an intermediate location on a travel path.

CONCLUSION
UAV is the area where the future belongs. Recent development has enabled UAVs to be a part of the common human life. UAVs as distributed sensor networks for IoT, pizza delivery units, postal delivery systems, aerial photography and videography units, surveillance units, construction reviewing units, agricultural units, disaster management units are already being used at large. The wide variety of use cases is the reason for such popularity of the UAVs. UAVs that could be used as public transport vehicles are still under test phase and will be in market sooner than we can imagine. Possibilities with UAVs are enormous and is only bounded by imagination.

REFERENCE

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