Design and implementation of IEC 61499 standard-based controllers in a distributed control environment

Abstract

The Fourth Industrial Revolution changed how people work, live, and interact with each other and technology with a shift towards automation and data exchange that requires software to be portable, interoperable, configurable, and reusable between multiple Original Equipment Manufacturers (OEMs). The interoperability challenge is overcome by the adherence to governing standards by the producers of the different software programming environments that are used to develop the control systems. PLCOpen function blocks, Codesys integrated development environment, the IEC 61499 Standard, and the EtherCAT network topology, are all examples of software aspects that are used to improve the integration between automation hardware from different vendors. In this thesis, the MATLAB/Simulink software engineering environment is used to develop a mathematical model of a DC motor control system that is used to control the azimuth and altitude positional movements of a radio antenna dish. A full-state feedback controller is designed to increase the response time of the positional movements to a set point change. Integral control is also added to the system to compensate for the steady-state error caused by using a full-state feedback controller. The developed simulation model is tested in the Simulink software environment by analysing the results of a step response input to the system. The response of the DC motor open-loop system, a DC motor system with a controller, and a DC motor control system with added integral control, is compared and analysed. The effects of the network-induced delays are also analysed before implementing the controller on the hardware. The effects show that an increase in network delays leads to an increase in system instability. The thesis findings contribute to detailing the transformation process for the developed controller from the Simulink simulation environment to the TwinCAT 3 programming environment to allow for the real-time implementation of an actual DC motor. The transformed simulation model interacts with the DC motor from a PLC, through an EtherCAT network, to a remote motor controller. The real-time hardware-in-the-loop implementation results are compared to the results acquired by the simulations done in Simulink. The results show that the effects of network delays are the same in real-time as in the simulation model. The addition of Beckhoff’s time compensation feature in TwinCAT 3 reduced the effects of time delays and resulted in a stable system. The control system is also stress-tested to record the limitations of the positional movements. The thesis findings and deliverables further contribute to the enlarging of the knowledge base in the field of IEC 61499 standard-based control systems and can be used for education to continue further research. The state-space method used in the mathematical model for the design of the controller can be implemented in other similar applications that require a change in angular position. The hardware-in-the-loop test rig can also be used in future research work by postgraduate students at universities or research institutions.