An experiment in distributed objects for real-time process control

Control systems for process plants are complex applications running in several interacting computers with varying degrees of integration. The construction, deployment and maintenance of the software system is a difficult problem and distributed object oriented technology offers a good way to deal with it. The open standard CORBA provides flexible middleware capable of integrating complex applications in heterogeneous environments, but was originally designed with large business applications in mind and is not perfectly suited for the construction of control systems. Even with recent advances in the real-time specification for CORBA, it is only suitable for soft real-time applications and does not deal with the tight requirements of closed control loops. This paper describes the HRTC project, an experiment of CORBA-based control systems. This project addresses the analysis of the technology and the implementation of two testbeds, one in process control and another one in robot control. The benefits of such technology are discussed.