Liveness-enforcing supervisors synthesis for a class of generalised Petri nets based on two-stage deadlock control and mathematical programming

2012 IEEE International Conference on Automation Science and Engineering (CASE)

Liu

Zhou

2012

Self Cite

This work presents an iterative liveness-enforcing method for a class of generalized Petri nets, which can model flexible manufacturing systems. The proposed method checks the liveness of net models using mixed integer programming and controls the token allocations of resource places instead of siphons using a liveness and resource usage ratio-enforcing supervisor. The enumeration of a kind of special structures, which is required in the previous work, is avoided and the number of iterations is bounded by the number of shared resource places in the net model. All strict minimal siphons in the controlled systems are minimally controlled. Several explanatory examples are used to illustrate this method.

Section: Mip and Lrsmentioning

confidence: 99%

Section: Mip and Lrsmentioning

confidence: 99%

See 1 more Smart Citation

On iterative liveness-enforcement for a class of generalized Petri nets

2012 IEEE International Conference on Automation Science and Engineering (CASE)

Liu

Zhou

2012

Self Cite

“…However, it does not lower the computational complexity because it still needs complete siphon enumeration. To avoid this disadvantage, our previous work in [10] proposed an iterative deadlock prevention policy for generalized Petri nets by using MIP-based deadlock detection technique, leading to better computational efficiency. However, the approaches based on either a complete or partial siphon enumeration are computationally expensive in theory.…”

Section: Introductionmentioning

confidence: 98%

A deadlock detection and prevention method for a class of generalized petri nets under proper resource allocation

Zhao

2013 IEEE International Conference of IEEE Region 10 (TENCON 2013)

2013

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This paper develops a computationally efficient deadlock control policy for a class of generalized Petri nets, called G-system that can well model machining, assembly and disassembly operations. The primary focus of this research is to design a liveness-enforcing supervisor in polynomially computational complexity. First, an extraction algorithm of liveness requirement constraints with polynomial time complexity is presented with respect to different resource allocation orders. In order to properly allocate the system resources for various processes requirements, monitors are added for the net model in terms of precise liveness requirement constraints. Accordingly, an iterative deadlock control algorithm is established based on mixed integer programming (MIP) such that the resulting net system has no deadlock state. The proposed method can lead to a liveness-enforcing supervisor with high computational efficiency.

“…However, the siphon-based control policies for G-systems are of exponential complexity due to a complete or partial siphon enumeration. 50,51 Furthermore, the behavioral permissiveness problem is referred to as the fact that permissive behavior is overly restricted by the siphon-based control policies, that is to say, the supervisor excludes some safe (admissible) states. This is so since the output arcs of a monitor are led to the source transitions of the net model, which limits the number of workpieces being released into and processed by the system.…”

Section: Motivation Of Deadlock Prevention Policy For G-systemsmentioning

confidence: 99%

Near-optimal supervisory control of flexible manufacturing systems using divide-and-conquer iterative method

Zhao

Uzam

Advances in Mechanical Engineering

2016

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This article proposes an iterative deadlock resolution method for flexible manufacturing systems modeled with G-systems. To design a non-blocking controlled system with maximally permissive behavior in a G-system (GS), a reachability graph-based analysis technology is utilized. Since the reachability graph of a large-scale GS easily becomes unmanageable, an optimal non-blocking supervisor becomes a challenging problem in a GS. To facilitate this problem, the Divide-andConquer approach is a good choice for complex G-systems. First, an uncontrolled GS resolves into a number of associated subnets. Then, every subnet suffering from deadlocks is utilized to design the liveness-enforcing supervisor for the original GS. Thus, additional monitors can be obtained if the liveness of all subnets is achieved. Subsequently, a partially controlled GS is derived by including all monitors within the GS, and its liveness can be ensured by designing a new set of monitors. Consequently, a non-blocking GS is derived. The major advantage of the proposed method is that a nonblocking supervisor with near-optimal behavioral permissiveness can be obtained in general. Finally, a typical GS example popularly studied in the literature is applied to demonstrate the validity and the availability of the method in this article.