CN-117369273-B - Method for designing activity supervision controller of automatic manufacturing system

Abstract

The invention discloses an activity supervision controller design method of an automatic manufacturing system. Automated manufacturing systems are modeled by a class of Petri nets. For a controllable transition in the Petri network, the invention constructs a subset from an initial state set with an activity supervision control strategy, and the controllable transition is always enabled regardless of the emission of the uncontrollable transition in any state of the subset. And constructing a sub-controller according to the subset, wherein the sub-controller controls the enabling of the controllable transition. After all the sub-controllers of the controllable transitions are constructed, a coordinator is constructed to coordinate the sub-controllers, and the coordinator ensures that only one controllable transition is allowed to transmit in one state. The invention converts the original activity supervision control strategy into the Petri network model to form a unified closed-loop controlled system, thereby simulating and analyzing by means of analysis software of the Petri network.

Inventors

• CHEN CHEN
• HU HESUAN
• Lv Zhangyi

Assignees

• 西安电子科技大学

Dates

Publication Date

20260508

Application Date

20231108

Claims (5)

1. 1. A method of designing an active supervisory controller for an automated manufacturing system, comprising: abstracting the automatic manufacturing system into a Petri net model; for any one of the first controllable transitions in the Petri net model, from an initial state set of the Petri net model with an active supervisory control strategy In which a second subset is constructed At the second subset In any state, the first controllable transition is always control-enabled, no matter how the uncontrollable transition is emitted, the second subset is constructed Comprises a slave To construct a first subset At the first subset In either state, the first controllable transition is control-enabled from the first subset The second subset is constructed ; According to a second subset of all the first controllable transitions Construction of double-layer active supervision controller The bottom layer is respectively a sub-controller for controlling each first controllable transition enable The top layer is a coordinator for controlling the enabled first controllable transition emission, the coordinator only allows one first controllable transition emission in the same state, and the sub-controllers Comprising a first warehouse A second warehouse And with a second subset A second controllable transition set corresponding to the states in a one-to-one mode, a second library Comprising a Token in an initial state, using a second library A second set of controllable transitions and a first library The sub-controller controls the enabling of the first controllable transition The design method of (2) comprises the following steps: adding up Second controllable transitions Respectively with the second subset Is in one-to-one correspondence with the states of the (c), For the second subset State quantity in (a); Adding a first warehouse And a second warehouse At a second store A Token is put in; For each of And , Is a second subset Is used to determine the identity of the set of (c), From the slave To the point of Adding an arc with an arc weight value of And from To the point of Arc weight of (2) is ; Adding transitions from the second controllable state To a first store Adding a first library to the connection arcs of the first library A connection arc to the first controllable transition, wherein the arc weights are all 1; respectively add slave second stores To a second controllable transition Adding the first controllable transition to a second library The arc weights are all 1.
2. 2. The method for designing an active supervisory controller for an automated manufacturing system according to claim 1, wherein said sub-controllers A method of controlling a first controllable transition enable, comprising: Sub-controller Detecting an identity of greater than or equal to When a certain mark in the network is detected, the sub-controller Allowing the corresponding second controllable transition to emit, after the second controllable transition is emitted, the corresponding first controllable transition is controlled by the sub-controller Enabling.
3. 3. The method of designing an active supervisory controller for an automated manufacturing system according to claim 1, wherein said coordinator comprises a third library The third library Comprising a Token in an initial state, using a third library For the first controllable transition and the second controllable transition Forming a closed loop control.
4. 4. The method of designing an active supervisory controller for an automated manufacturing system according to claim 3, wherein said method of designing a coordinator comprises: Adding a third warehouse And put into a Token; for each sub-controller Any second controllable transition in (a) Adding a third library To a second controllable transition Is connected with the arc of the arc weight value Wherein , Z is the controllable transition number in the Petri net model; Adding, for each first controllable transition, transitions from the first controllable transition to a third library Is connected with the arc of the arc weight value 。
5. 5. The method of designing an active supervisory controller for an automated manufacturing system according to any one of claims 1 to 4, further comprising: The double-layer activity supervision controller Added to a Petri net model of the automated manufacturing system.

Description

Method for designing activity supervision controller of automatic manufacturing system Technical Field The invention relates to the field of automatic manufacturing, in particular to an active supervision controller design method of an automatic manufacturing system. Background Over the past decades, with the widespread use of information technology, automation technology and computing technology, conventional manufacturing systems have gradually shifted to automated manufacturing systems with the aim of greatly reducing manufacturing costs, improving product quality and ensuring production safety, and allowing quick response to market changes and customization requirements. Deadlock free in an automated manufacturing system can be analogous to stability in a continuous system, and a manufacturing system is not acceptable in spite of its excellent performance once deadlock occurs, as this means that the system may be at any time with production stalling, with serious or even catastrophic consequences. The problem of deadlock in automatic manufacturing systems is solved, and three mathematical tools, directed graph, automaton and Petri net, are mainly adopted by people. The Petri net can more properly simulate, analyze and control an automated manufacturing system. Because of the clear structural features and strict mathematical expression of the Petri net, researchers are easy to develop relevant analysis software for analyzing many characteristics of the Petri net, such as activity. Deadlock prevention in automated manufacturing systems based on Petri nets has achieved a number of research efforts. Most automated manufacturing systems are modeled using Petri networks of the S3PR or S4R type, and most solutions are largely divided into three types, namely, reachability graph-based analysis methods, structure-based analysis methods, and combinations of both. In the presence of a maximally licensed active supervisory controller, methods based on reachability graph analysis generally achieve maximum licensing. However, traversing the reachability graph faces the problem of state explosion, so that the method is suitable for the Petri network with smaller scale. The analysis method based on the structure fully utilizes the structural characteristics of the Petri net, and achieves the purpose of preventing deadlock by controlling the characteristic structure. However, the combination of features grows exponentially with the size of the Petri net, and this type of approach generally does not achieve maximum licensing behavior. There are also methods that combine structural analysis with reachability graph analysis, and although researchers have attempted to simplify controllers, the methods are more applicable to systems with less large Petri nets. For the selection of the free Petri net, paper "On the Existence of Supervisory Policies That Enforce Liveness in Partially Controlled Free-Choice Petri Nets" proposes a novel activity supervision control strategy. The selected free Petri network is FCPN for short, is a typical type of Petri network and is widely applied to modeling, analysis and control of automatic manufacturing systems, logistics systems, communication protocol systems, multiprocessor systems and concurrent systems. With respect to FCPN, the paper demonstrates that for any one FCPN, when an activity supervisory control strategy is present in the m state, the activity supervisory control strategy is present in any one of the m or more states. Thus, the set of all states for which an activity supervisory control strategy exists, denoted as Δ (N), is right-closed. The state set may be uniquely identified by its smallest element min (e.g., min (Δ (N))). On this basis, the paper proposes FCPN an activity supervision control strategy, given a Petri net with an initial state m 0, denoted N (m 0), assuming a controllable transition t c enabled in the m state, further assuming that m 'is the state reached after the emission t c, if m' is equal to or greater than one element in min (Δ (N)), the controllable transition t c allows emission, otherwise t c cannot be emitted. The activity supervisory control strategy of this type is characterized by 1) having maximum allowable behavior and 2) having a state increment feature. The method comprises the steps of (1) providing an activity supervision control strategy in an m state, and providing the same activity supervision control strategy in any m state or more, 3) not traversing a reachable graph of a system, not analyzing structural characteristics of a Petri network, only calculating min (delta (N)) through software, and 4) providing the activity supervision control strategy with universality and no relation with the initial state of the system. However, the controller model and the system model are not unified, which is a problem facing the controlled system. In other words, the system model is modeled by the Petri net, and the activity supervision controller i