Change search
ReferencesLink to record
Permanent link

Direct link
Non-Linear Automatic Control of Autonomous Lawn Mower
Linköping University, Department of Electrical Engineering, Automatic Control.
2016 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

This master thesis contains modeling and nonlinear automatic control of an autonomous lawn mower. The vehicle shall be able to follow a magnetic field loop buried in the lawn on an arbitrary distance, including straddling. A unicycle model of the lawn mower has been derived based on previous work. The model holds for the assumption of non slip environment. Two diff erent control strategies have been implemented and evaluated in this thesis. One is based on feedback linearization  and with the feedback gain estimated using an LQ-controller. The other strategy is based on linearization at an equilibrium point  and also with the use of an LQ-controller. The only state that can be measured is the distance to the magnetic loop. In order to estimate the other states, an observer has been implemented using the linearized in an equilibrium point  model and a Kalman filter. The navigation of the autonomous lawn mower is performed using a magnetic loop buried in the lawn. The non-linearity of the magnetic field causes diffi culties when estimating the distance to the loop. One magnetic field strength corresponds to two distances to the magnetic loop. The nature of the magnetic field and the measurement noise causes the precision of the controller to be limited. The conclusion of this master thesis is that it is possible to navigate and follow the magnetic loop at a distance greater than 0.3 [m], but with overshoots during sharp turns. If the reference distance is smaller than that, the behavior of the robot will be oscillating when following the loop. The limitations of the controller performance is due to the lack of information which can be extracted from the measurements of the magnetic field.

Place, publisher, year, edition, pages
2016. , 48 p.
Keyword [en]
autonomous lawn mower, non-linear automatic control
National Category
Control Engineering Robotics Signal Processing
URN: urn:nbn:se:liu:diva-129116ISRN: LiTH-ISY-EX--16/4966--SEOAI: diva2:935778
Subject / course
Automatic Control
2016-06-01, Filtret, Linköpings universitet, Linköping, 14:00 (Swedish)
Available from: 2016-06-14 Created: 2016-06-12 Last updated: 2016-06-14Bibliographically approved

Open Access in DiVA

fulltext(2140 kB)55 downloads
File information
File name FULLTEXT01.pdfFile size 2140 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Dysenius, Hannah
By organisation
Automatic Control
Control EngineeringRoboticsSignal Processing

Search outside of DiVA

GoogleGoogle Scholar
Total: 55 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: 122 hits
ReferencesLink to record
Permanent link

Direct link