Research on Real-Time Scheduling Strategy for Transient Fault Tolerance in NC System

Numerical control (NC) system is a hybrid-tasks system (HTS), which is made up of periodic real-time tasks, aperiodic real-time tasks and non-real-time tasks. To guarantee the time determinability and reliability of NC system, a HTS model describing all three kinks of task with temporal parameters tuple was established and the heuristic best-first search (BFS) algorithm was introduced to schedule tasks of this model. Then a fault-tolerance scheduling strategy based on rollback recovery and BFS algorithm was proposed to remove transient faults of system. Comparing to traditional fault-tolerance scheduling algorithm, the strategy presented in this paper is applied to schedule mixed and dependent tasks of NC system, and raises the level of resources utilization by reducing the cost of fault disposal. The validity of this proposed approach applied to NC system is verified in case study and algorithm simulation