Unmanned System

Unmanned Systems Technology (UST) is the software and hardware systems that operate semi- and fully-autonomous vehicles. The UST used in an autonomous vehicle determines its capabilities and reliability, especially those possible without human input or correction, which is the definition of autonomy.

An unmanned aerial vehicle (UAV) (or uncrewed aerial vehicle, commonly known as a drone and rarely as an uninhabited aerial vehicle or unoccupied aerial vehicle) is an aircraft without a human pilot onboard and a type of unmanned vehicle. UAVs are a component of an unmanned aircraft system (UAS); which include a UAV, a ground-based controller, and a system of communications between the two. The flight of UAVs may operate with various degrees of autonomy: either under remote control by a human operator, autonomously by onboard computers or piloted by an autonomous robot.

Classification

UAVs typically fall into one of six functional categories (although multi-role airframe platforms are becoming more prevalent):

  • Target and decoy – providing ground and aerial gunnery a target that simulates an enemy aircraft or missile

  • Reconnaissance – providing battlefield intelligence

  • Combat – providing attack capability for high-risk missions

  • Logistics – delivering cargo

  • Research and development – improve UAV technologies

  • Civil and commercial UAVs – agriculture, aerial photography, data collection

UAV components

Crewed and uncrewed aircraft of the same type generally have recognizably similar physical components. The main exceptions are the cockpit and environmental control system or life support systems. Some UAVs carry payloads (such as a camera) that weigh considerably less than an adult human, and as a result, can be considerably smaller. Though they carry heavy payloads, weaponized military UAVs are lighter than their crewed counterparts with comparable armaments.

  • Body

  • Power supply and platform

  • Computing

  • Sensors

  • Actuators

  • Software

Loop principles

UAVs employ open-loop, closed-loop or hybrid control architectures.

  • Open-loop – This type provides a positive control signal (faster, slower, left, right, up, down) without incorporating feedback from sensor data.

  • Closed loop – This type incorporates sensor feedback to adjust behavior (reduce speed to reflect tailwind, move to altitude 300 feet). The PID controller is common. Sometimes, feedforward is employed, transferring the need to close the loop further.

  • Flight controls

  • Communications

Basic principles

One way to achieve autonomous control employs multiple control-loop layers, as in hierarchical control systems. As of 2016 the low-layer loops (i.e. for flight control) tick as fast as 32,000 times per second, while higher-level loops may cycle once per second. The principle is to decompose the aircraft's behavior into manageable "chunks", or states, with known transitions. Hierarchical control system types range from simple scripts to finite state machines, behavior trees and hierarchical task planners. The most common control mechanism used in these layers is the PID controller which can be used to achieve hover for a quadcopter by using data from the IMU to calculate precise inputs for the electronic speed controllers and motors.

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