A Robust Control Approach to AMSs by Using the Implementation of Strong and Weak Robustness
Xiaojun Wang, Hesuan Hu · IEEE Transactions on Systems Man and Cybernetics Systems · 2023
In automated manufacturing systems, the completion of all essential products must be guaranteed. Hence, each process of a system should have outputs. This outcome requires assurance that a system composed of a set of processes with shared and dedicated resources will operate smoothly. Shared resources can introduce deadlock problems through circular waits. In most methods to investigate the deadlock issues, shared and dedicated resources are assumed to never fail. However, the failure of one resource may cause the real crash of an entire system such that no finished products can output. Systems with unreliable resources are classified in this article into three types: 1) nonrobust systems; 2) weakly robust systems; and 3) strongly robust systems. A robust control method based on this classification is necessary for a system. Two approaches to robust control are developed. First, systems of sequential systems with shared and copied resources$(S^{4} C R\text{s}$), which is a new type of petri nets, is designed to strengthen the robustness of systems. It ensures that processes with unreliable resources complete their products. In addition, based on a deadlock-avoidance algorithm, a robustness algorithm is proposed. This ensures a system can operate without disruption under any situations.