Abstract
An approach to intelligent process automation based on
distributed planning agents is presented in this paper.
According to this approach a higher-level agent-based
automation layer supervises an ordinary process
automation system. The purpose of the agent layer is to
monitor the operation of the lower-level automation system
and semi-autonomously reconfigure its control logic when
needed. The agent layer operates as a distributed planning
and plan execution system, which creates and runs
reconfiguration sequences on the ordinary automation
system in order to adapt it to various situations. In this way
the approach aims to increase the operational flexibility of
the whole automation system. The approach is
demonstrated with a laboratory test process where process
startup scenarios have been imitated. Experiences from the
initial test runs are also described.
1 Introduction
The research effort described in this paper is motivated by
two factors: the gradually increasing functional
requirements of process automation and the progress of
agent technology. Although the requirements of process
automation have traditionally focused on reliability,
efficiency and quality [14], recently operational flexibility
and easier system maintenance have been emphasized as
well [20]. Agent technology [24] has been studied as
possible means to reach such objectives as indicated by the
research in other application domains, e.g. communication
systems [7]. Our research objective is to specify a
reasonable way to utilize agent technology in order to build
a process automation system with the desired properties of
enhanced flexibility and easier system maintenance.
The purpose of this paper is to present an approach to
intelligent process automation based on distributed
planning agents. In this context the purpose of intelligence
in process automation is to gain increased flexibility in
process control operations and at the same time to enhance
the maintenance of process automation systems.
Our approach to intelligent process automation is based
on multi-agent systems (acronym: MAS) performing
distributed planning. We expect that the methods of the
planning type of MAS will help with the presented
objectives. The functional responsibility of the agents is to
plan and execute higher-level control sequences, e.g.
startup, shutdown, state change, batch process and
abnormal situation handling procedures. This study
complements our previous experiments with process
automation agents based on a reactive operation scheme
[16][17]. These experiments led us to a conclusion that
agents with purely reactive operation scheme are only
applicable to a limited set of process automation
operations. A suitable combination of planning and
reactive operation is needed for extended functionality.
The paper is outlined as follows. Chapter 2 will discuss
intelligent process automation, planning agents and their
applications to process automation. Our concept of an
agent-augmented process automation system containing
planning agents is presented in Chapter 3. The distributed
planning and plan execution processes of the system are
described in Chapter 4. The test environment and an
experiment with it are depicted in Chapter 5 followed by
conclusions in Chapter 6.
2 Planning Agents and Intelligent Process
Automation
Intelligent supervisory control has been a research topic in
process automation for already quite a time; see e.g. [22].
The basic idea of this concept is to extend process
controllers with reasoning capabilities of artificial
intelligence. The intelligence is in a supervisory controller
that guides the operation of an ordinary primary controller.
Experimented inference techniques include e.g. rule-based
reasoning, fuzzy logic and qualitative modeling. However,
regardless of the inference mechanism the model of
operation in these approaches has been centralized.
Distributed planning is one of the research topics of
distributed artificial intelligence [24]. Several methods for
planning in different situations with varying degree of
Distributed Planning Agents for Intelligent Process
Automation
Ilkka Seilonen
1
, Teppo Pirttioja
2
, Pekka Appelqvist
2
, Aarne Halme
2
, Kari Koskinen
1
Helsinki University of Technology
1
Information and Computer Systems in Automation,
2
Automation Technology Laboratory
Espoo, Finland
1
www.automationit.hut.fi,
2
www.automation.hut.fi
614
Proceedings 2003 IEEE International Symposium on
Computational Intelligence in Robotics and Automation
July 16-20, 2003, Kobe, Japan
0-7803-7866-0/03/$17.00 ©2003 IEEE