FöRFATTARE
Uthaicharoenpong, Tawon

INSTITUTION
Rymdvetenskap, Kiruna /

SAMMANFATTNING
Future planetary exploration missions will require mobile robots to excess challenging terrain such as rocky areas, steep slopes or loose soil types which make robots susceptible to losing stability leading to rollover or entrapment. So far this problem have been proposed to be solved by the use of reconfigurable robots, robots that can reconfigure themselves, these robots have an advantageous ability to reconfigure themselves to optimize their performance according to the surrounding area, i.e. to adjust wheel diameter according to soil conditions to optimize wheel-ground traction, to adjust shoulder joint angles to keep the center of gravity within a suitable area thus increasing tip over stability. To define and give a measure of stability, which has no official unit and theory yet, various kinds of stability measures have been studied and discuss about the drawback and generality of each measure. The most suitable measure selected to be implemented in this thesis work is the force-angle stability measure. The conceptual design of the robot prototype built with the help of a 3D mechanical design program, which later was used to find many important parameters of the robot, afterward it was then manufactured within the TKK Automation laboratory facility. It is a four wheeled skid-steer robot platform with an inverted pendulum mounted on top.

Control software has been developed both for the local controller (AT90CAN128 from Atmel), where the manipulator position control method is run, as well as on the PC where the implementation and development of force- angle stability measures take place using MATLAB. The robot prototype was then tested to measure the performance of the robot and to investigate how the system reacts to various test method. The test data was collected and analyzed and was proven to significantly enhance the stability of the robot.

ISSN 1653-0187 / ISRN LTU-PB-EX--08/115--SE / NR 2008:115