IoT Techniques and Elements for Drone Package Delivery Networks
power approaching two kilowatts per motor ( although in level flight , they will only use a fraction of this ).
5.1.2 BATTERIES
Batteries are a critical component of the drone . Lithium polymer batteries are the standard , as they have the best mix of weight , total energy stored , and total power for drone applications of widely available battery chemistries . There is a constant tradeoff between the weight and size of the batteries , the cargo capacity of the drone , and its flight characteristics ( speed , range , maneuverability , etc .). Most of the battery energy goes through the motor speed controllers to the motors and propellers , but a small fraction is used to run other loads like processors , cameras , sensors , lights , and cargo management systems .
Typical cargo drones balance the energy to provide about 30 minutes of flight time with their maximum rated payload weight at a typical cruising speed of 40-80 km / h . This creates an operational round-trip range of 10-20 km without remote recharging . Of course , if some payload weight is sacrificed to carry larger capacity batteries , this range can be extended , to a point . Hydrogen fuel cells are a promising energy storage technology for longer-range drones .
5.1.3 FLIGHT CONTROL COMPUTER
The next important subsystem of a drone is the flight control computer . The primary task of the flight control computer is to accept pilot / autonomous control commands , read a collection of sensors , and provide digital command signals to the motor speed controllers for each rotor . Pilot commands can be direct inputs from live joysticks controlling pitch , yaw , roll speed , direction and altitude .
However , most modern cargo drones have some form of autopilot that accepts commands at a higher level . For example , “ take off from the current location , ascend to ZZZ meters , and fly to a waypoint at GPS coordinates ( XX , YY ).” By stringing together several waypoints , a flightpath can be assembled to move the drone to the desired destination , while avoiding terrain , obstacles or restricted flight zones . Then , after hovering at the last waypoint , precision landing systems can automatically bring the drone to a safe touchdown to load or unload its cargo .
A number of sophisticated IoT sensors feed flight related information into the flight control computer . Gyroscopes measure the pitch , yaw and roll angles and rates of change , accelerometers measure acceleration in three axes , and the algorithms in the flight control computer compare these readings to desired values and change the motor speed settings to correct errors between commanded and measured states . Magnetic compasses are sometimes employed to find headings , but their accuracy is often disturbed by metal or magnets in the cargo . Absolute position sensors typically use Global Navigation Satellite Systems ( GNSS ) like GPS ( USA ), GLONASS ( Russia ) or Galileo ( EU ) to fix their position with a typical accuracy of about five meters [ 17 ].
36 August 2023