Software Fault Tolerance for Cyber-Physical Systems via Full System Restart

Abstract

The paper addresses the issue of reliability of complex embedded control systems in the safetycritical environment. In this paper, we propose a novel approach to design controller that (i) guarantees the safety of nonlinear physical systems, (ii) enables safe system restart during runtime, and (iii) allows the use of complex, unverified controllers (e.g., neural networks) that drive the physical systems towards complex specifications. We use abstraction-based controller synthesis approach to design formally verified controller that provides application and system-level fault tolerance along with safety guarantee. Moreover, our approach is implementable using commercial-off-the-shelf (COTS) processing unit. To demonstrate the efficacy of our solution and to verify the safety of the system under various types of faults injected in applications and in underlying real-time operating system (RTOS), we implemented the proposed controller for the inverted pendulum and three degree-of-freedom (3-DOF) helicopter.1 Such systems usually use the operating system (OS) primitives to perform I/O or to set up concurrent threads [Lee08], utilize vendor developed drivers and use open source libraries [SOAB + 14].2 In this paper, safety means not to violate the constraints of the physical components.