Change search
ReferencesLink to record
Permanent link

Direct link
Design and Implementation of a Glider Control System
KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory.
2015 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

ROBEX is a unique research project combining Airbus Defence and Space’s robotics expertise with deep-sea exploration technology to discover more about the most extreme environments environments known to man. As a part of this project, a deep-sea glider called MOTH, is under development with the objective to determine whether gliders can be used as a platform for bathymetric and electromagnetic soundings of the seafloor as well as for new water column research. This master’s thesis aims to design and implement the MOTH glider’s control system.

The glider will have an independent emergency system, a power unit, an on-board computer (OBC), actuators, navigation sensors and scientific measurement instruments which can be swopped between missions and are connected via remote terminal units. The selected OBC is a Linux embedded Axotec GX-6300 with RS232 and CAN bus interfaces, as selected in the electrical architecture, and the chosen operative system is Linux Debian. The glider communicates with GNS/Iridium antenna and also has an ethernet cable link for ground station operations and a future option of an acoustic transceiver.

To control actuation, the glider is equipped with a rudder, a left and a right wing flap, a moveable mass and a buoyancy tank. It travels in sawtooth patterns and is therefore always descending, ascending or transitioning during operation and at times ascending all the way to the surface to transmit and receive data via satellite communication. A model based feedback controller for longitudinal control has been programmed based on the equations of motion described in this report. The modelled longitudinal trajectory is as desired until a transition point is reached, the model is, presumable because of the uncertainty of the model parameters, unstable as the actuators are unable to correct the pitch angle.

An AHRS navigation sensor emulator and an OBC emulator have been programmed to simulate the communication between these two and the emulated system is well operating both as a continuous stream and for polling data. The emulator and the pitch controller, when updated parameter values are available, will be used for simulation and verification tests in the laboratory environment.

The ROBEX alliance will, if the objectives with the MOTH glider are met, continue to design gliders with the aim to increase the maximum duration time and speed in order to reach greater depths of the oceans.

Place, publisher, year, edition, pages
TRITA-MAT-E, 2015:16
Keyword [en]
ROBEX, MOTH, glider, buoyancy, OBC, actuators, pitch, deflection, AHRS
National Category
URN: urn:nbn:se:kth:diva-167355OAI: diva2:813229
Subject / course
Systems Engineering
Educational program
Master of Science - Aerospace Engineering
Available from: 2015-05-22 Created: 2015-05-22 Last updated: 2015-05-22Bibliographically approved

Open Access in DiVA

fulltext(2848 kB)367 downloads
File information
File name FULLTEXT01.pdfFile size 2848 kBChecksum SHA-512
Type fulltextMimetype application/pdf

By organisation
Optimization and Systems Theory

Search outside of DiVA

GoogleGoogle Scholar
Total: 367 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 225 hits
ReferencesLink to record
Permanent link

Direct link