The Complexity Measurement Research Of Human Machine Interaction In Digital Control System

The complexity of the human machine interaction brings a huge challenge to theoperator. It not only can reduce operator’s situational awareness, increase thecognitive load, but also can cause human error, and even die in the accident. Today,especially with the constant development of information technology, the applicationof the digital control system in industrial enterprise is more and more widely, and thecomplexity of the human machine interaction may affect the safety and reliability ofthe whole system. Therefore, researching the complexity of human machineinteraction in the digital control system has an important significance. So howcomplex the human machine interaction is and how to clearly express the complexity?Based on these problems, the complexity metrics is studied.Under the background of digital control system, and based on the analysis of thetheoretical study of digital control system, human machine interaction and complexity,the complexity measurement process based on entropy is established, which analyzeshuman machine interaction complexity of emergency operating procedures of steamgenerator tube rupture in a certain digital plant. The results show that the proposedmethod is reasonable and feasible. At last, some reasonable suggestions are putforward in order to prevent and reduce the complexity of human machine interactionbased on the analysis of the research results. Through the study, this thesis gets thefollowing conclusions:(1) The complexity of the human machine interaction influence mechanismmodel is put forward based on the theoretical study of the complexity of humanmachine interaction, four key factors and metrics of which can effectively quantify thecomplexity of human machine interaction in digital control system.(2)The information entropy theory can quantitatively describe the complexity ofthe human machine interaction in digital control system. By the information entropytheory, it can represent the complexity. Then the method combining with the expert investigation method and the entropy is considered to be more reasonable to evaluateindex by comparing complexity metrics method. And the entropy of each index iscalculated by using the first order entropy and the second order entropy of theinformation entropy.(3)From the step18and step19of SGTR procedures in a certain nuclear powerplant, the results showed that the complexity of the step18is much larger than step19and so does the complexity of each index. It can be applied to choose optimizationscheme by calculating complexity. At the same time, according to the comparison ofeach index of step18and step19respectively，some measures can be takenpertinently to reduce the complexity of the index. This study has a certain role inguiding for selecting human machine interaction scheme, distributing the operationtime, designing and optimizing procedures and human interface design in industrialsystem.