Agent oriented software-development for networked embedded systems with real time and dependability requirements in the domain of automation

Abstract

A method for integrated development of multi agent PLC based control systems using IEC 61131-3 will be introduced. Dependability of technical plants will increase if control behaviour can be adapted during runtime. This is achieved by dynamic reconfiguration of faulty devices, e.g. sensors, at run-time. The replacement is based on analytical redundancy that is represented by a network of sensors and their interdependencies. This method supports the developer to sketch a suitable modular softwarearchitecture in regards to the hardware-architecture and the specific requirements of real-time and dependability. The integration of classical methods like fault-tree-analysis and graph-theory enables the developer to build a knowledge-based system so that the agents would have the ability to recognize faults, seize the needed actions within their scope and fulfil their goal. Recent investigations using a model-plant showed the feasibilities of this approach.

Agents enabling cyber-physical production systems

“…In [42,43] a multi-agent system following this definition is presented which enables dependable production in presence of sensor failures. Agents are dedicated to physical equipment, e.g.…”

“…assure communication between agents which fulfills real-time requirements and avoid agents' actions with unknown results. The agent paradigm with negotiations in between agents as well as learning and acting on the agent's knowledge is restricted to safe actions [17,42]. The implementation on Programmable Logic Controllers (PLCs) is also discussed in Section 3.…”

Usability challenges in the design workflow of reusable PLC software for machine and plant automation

“…This interface allows the user to map a sensor signal to more than one module. In addition virtual sensors [18] can be added to modules. These virtual sensors are registered and can be accessed as ports in the IO table, Figure 4).…”

Real-time capable software agents on IEC 61131 systems – Developing a tool supported method

“…An approach to enhance the reliability of plants in production automation as well as in process automation using software agents was developed and presented in (Wannagat et al, 2008a). This approach integrates the concept of virtual sensor redundancy within software agents.…”