Laser guided vehicles : implementing and testing a GIMnet based software platform on the electric wheelchair MICA

This thesis presents hardware and software implemented on the electric wheelchair MICA (Mobile Internet Connected Assistant). The work done in this project involved the whole chain from mounting sensors on MICA, developing drivers and software for the sensors and the development of algorithms for autonomous driving. The drivers and software were developed with flexibility and reuseability in mind. The backbone part of this thesis was the implementation of GIMnet (Generic Intelligent Machine Network), a communication infrastructure for robot control. A socket server and a socket client was developed in order to receive data directly into MATLAB and control MICA from MATLAB. Different tests were made to evaluate the performance of GIMnet, with regard to time delay. These tests also served to evaluate how well all the developed software, drivers and algorithms worked together. The time delay tests were made locally on the MICA computer and showed that even under high load the time delay in GIMnet stayed within acceptable margins. Tests of how well all the instruments and software were able to preform together were made by implementing the Circle Sector Expansion (CSE) algorithm. The CSE algorithm focuses on finding the largest space instead of geometry of the obstacles. CSE was implemented using MATLAB and collected data from all the sensors and equipment before making the calculations. By using the CSE algorithm MICA was able to drive autonomously with fairly good ability to avoid dynamic obstacles. A dead reckoning algorithm to calculate traversed distance was also implemented. When the precision of this was tested during a 150 m test run it was found that the accumulated dead reckoning error was 0,3 m, which is quite good for such a distance.Validerat; 20101217 (root