Study on cooperative positioning system (basic principle and measurement experiment)

Several position identification methods have been used for mobile robots. Dead reckoning is a popular method, but is not reliable for long distances or uneven surfaces because of variations in wheel diameter and slippage. The landmark method, which estimates current position relative to landmarks, cannot be used in an uncharted environment. We have proposed a new method called 'Cooperative Positioning System (CPS).' For CPS, we divide the robots into two groups, A and B. One group, A, remains stationary and acts as a landmark while group B moves. Group B then stops and acts as a landmark for group A. This 'dance' is repeated until the target position is reached. By using the concept of 'portable landmarks', CPS has a far lower accumulation of positioning error than dead reckoning, and can work in three-dimensions which is not possible with dead reckoning. CPS, therefore, can work in uncharted environments. In this paper, we outline a second prototype CPS machine model (CPS-II) and report the results of position identification experiments. Experimental results using this model give a positioning accuracy of 0.4% for position and 1.0 degree for attitude.