Safety Verification of Multiple Autonomous Systems by Formal Approach

Abstract

We have studied verification of a line tracing robot using model checking. In this paper, we extend the model to multiple autonomous systems, and describe the advantages of applying model checking and difficulties. The targeted line tracing robot usually has only one or two sensors to detect a line painted on white background, and it traces the line according to the read value of the sensors. It is easy to trace if the line is simple straight line. However, lines sometimes become complicated by existence of random sequential corners. Those robots are often used in robot competitions for university students in Japan. Driving time, accuracy and robustness are evaluated in such competitions. The robot is usually designed as a stand-alone. Here, we extend such line tracing robots to multiple autonomous robots by adding communication functions and proximity sensors. We consider multiple lines to be crossed where robots might hit each other. Although the introduced model is simple, it has enough power to provide a structure where we can discuss safety and robustness using model checking. Our proposed method can also treat time constraints of robot controls.