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Electronically steerable antenna stand tracking UAV using GPS
2004 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

This project was performed at the Department of Electrical and Computer Systems Engineering (ECSE) at Monash University in Melbourne, Australia. There are several projects ongoing at this department regarding Unmanned Aerial Vehicles (UAV) or remote controlled planes. During the test flights of these UAV: s, data is often transmitted to a receiver on the ground. The goal with the project was to design and construct an electronically steerable antenna stand to track an UAV. The project included the design of the antenna stand, actuators and a control unit (consisting of an embedded system). The system receives GPS (Global Positioning System) position data from the UAV and from this, compute output signals to the motor drive electronics. Feedback is given to the system from sensors located on the antenna stand itself and at the outgoing motor shafts. The mechanic part was first designed in a CAD program and then manufactured at the university workshop. To track a plane, the antenna stand needed to have two degrees of freedom, horizontal (azimuth angle) and vertical (elevation angle) rotation. The actuators to drive each axis were designed to get proper speed and torque, using DC motors, planet gearboxes and belt drives. Each actuator has one drive circuit and the two pulse width modulated (PWM) outputs from the microcontroller were used for speed control. The feedback sensors used here were of Hall-effect type, which combined with magnets give square output pulses. The sensors located on the antenna stand give limit indications for the antenna position, while sensors on the motor shafts give motor speed and direction. The motors were modelled in OrCad as well as the dynamics of the mechanical system and then simulations could give an idea of the system behaviour and how to dimension the electronic components. The main objects of the control unit were to receive and process GPS position and sensor data, keep track of the plane as well as antenna position, speed and direction. It should also calculate and output proper control signals in terms of PWM pulses to the drive circuits. All tests have been made in experimental setups while no opportunities have been given for testing during flights out on the field. The major problems during the project have been belt slip at the elevation belt drive and the stability of the control unit when trying to make all functions work together at once. There is still work left to be done to get a stable, fully functioning stand-alone product.

Place, publisher, year, edition, pages
Keyword [en]
Technology, UAV, GPS, antenna stand, mechatronics, embedded systems
Keyword [sv]
URN: urn:nbn:se:ltu:diva-55723ISRN: LTU-EX--04/259--SELocal ID: c8d2888a-b2ea-446a-8e54-b7e2b9b97714OAI: diva2:1029107
Subject / course
Student thesis, at least 30 credits
Educational program
Electrical Engineering, master's level
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

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