Control Flow Verification for Program Safety Update

In program update of control systems such as the function update, a span of update influence is not always clear in advance even if the number of LOC (lines of code) is small. We want to avoid unexpected behaviors; it is desirable to check rapidly whether the updated code does not affect the I/O processes which are not scheduled for update (non-updated I/O processes). Motivated by this, this paper proposes a program verification method for safety update of the embedded system. Especially, we consider a program safety update problem to check whether the control flow of the updated code does not include that of the non-updated I/O processes or not. The proposed method focuses on the periodic characteristic of I/O processes to extract control flow of I/O processes. We use periodic inputs of the controllable and observable subsystem. To verify the validity of the proposed method, this paper considers an autonomous mobile robot.