Fuzzy feedback scheduling algorithm based on central processing unit utilization for a software-based computer numerical control system

Abstract

The tasks of a software-based computer numerical control (CNC) system are characterized by concurrency, hybridization, and correlation, which makes system implementation difficult. The uncertainty factors when running real-time tasks affect control performance by degrading manufacturing accuracy as a result of restrictions on system resources and processor use. To address the technical difficulty of embedded system implementation, a novel fuzzy feedback scheduling algorithm based on CPU utilization for a software-based CNC system is proposed herein. Time characteristics such as sampling jitter, input—output jitter, and non-schedulability are discussed, followed by quantification through simulations of the impact of time characteristics on manufacturing accuracy. On the basis of this research, fuzzy feedback scheduling based on the loop-up table method is designed for a software-based CNC system in order to reduce mismachining tolerance. The simulated results show that machining precision rises by an order of magnitude or more, proving that the presented algorithm is effective. Moreover, the algorithm is independent of task execution times and is easy to implement while incurring only a small overhead.

Keywords

software-based computer numerical control system CPU utilization time characteristic fuzzy feedback scheduling manufacturing accuracy

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