Study On Physiological Functions And Assessment Of Mental Workload During Simulated And Deep-sea Submersible Operation

Jiaolong submersible dived increasingly frequently due to the demand of deep-sea resources exploration recently,which requires accessment of workload of Jiaolong submersible pilots.These pilots need to operate the submersible in complicated deep-sea environment with a high level of cognitive activity,which could induce a significant mental workload during work.This thesis aims to research on the changes of physiological functions and then use pattern recognization algorithms to evaluate mental workload during simulated and deep-sea submersible operation.Firstly,EEG and ECG signals and subjective ratings of submersible pilots were recorded during an approximately 3 h submersible operation task and then analysed.The operation task resulted in an increased HR in association with mental stress,alterations in autonomic activity and EEG changes that indicated variations in mental workload.Brain arousal level declined during the later operation period.Secondly,the heart rate variability(HRV)indices of submersible pilots and technicians during actual deep-sea submersible operation was analysed and then compared.The results showed that the sympathetic nerve activity increased in pilots but not in technicians during diving and rising,which might be due to the high workload during these two phases.The significant increase of HR during diving seems to indicate there were stress reactions in all subjects.Thirdly,in order to provide realistic submersible operating experiences for pilots to increase their proficiency in submersible operation,and adapt them to deep-sea operation environment,a submersible operating simulater was designed using Unity3 D and 3dsMax.This simulater is based on real world design of Jiaolong submersible and could simulate operating task of different types and levels of difficulty.Finally,a simulated submersible operating experiment involved 8 subjects was conducted using the simulator.These subjects were also required to do congnitive training between each two simulated operation tasks.The operation task included subtasks of different types and difficulty levels.The results showed that cognitive training could induce changes in EEG indices and improve task performance during simulated submersible operation.Then mental workload in subtasks of different difficulty levels was predicted by a classification model based on SVM(support vector machine)with an average accuracy of 79.2%.