Research On Production Efficiency Based On Mental Load

Recent years, Industrial engineering (IE) gradually steps into the period of electronization and automation with the development of science. During the process of production optimization, engineers incrementally realize that people are the bottleneck which restricts the promotion of production efficiency. The information of people status and production status should be merged together for the optimization of production management. If we purely focus on the production process but ignore the mental load of people, it will significantly influence the employee’s behavior and be negative for the promotion of production efficiency. More importanly, it runs against the original design concept of production management, i.e.,"machine serves people" has turned into "people give service to the machine". Therefore, it is of great value to research the mental load in the improvement of production efficiency.In order to understand the issue of production efficiency more profoundly, our thesis focuse on three important topics.1) Whether the mental load such as emotion, mental fatigue could influence the production efficiency?2) What is the neural and physiological mechanism of this influence?3) How to put the factor of mental load into the practice of production management in order to promote the production efficiency? With the purpose to figure out these issues, our thesis carries out four studies step by step as research object.With the method of questionnaire, study1explored whether emotion could influence the production efficiency and demonstrated the emotion dimension which attributed to this influence. Study1makes up the insufficient of previous researches and provides a research foundation for the following studies.Based on study1, study2explored the neural mechanism of the emotional impact on the reaction efficiency with the method of event related potentials (ERP).Study2not only examined the production efficiency in the micro level but also penetrated the method to the neuroscience level.Study3is the extending of study1and study2. This study focused on how the mental fatigue influenced the production efficiency and the physiological mechanism behind this influence. Meanwhile, study3put forward an index of neuro-efficiency which was used as a reference to measure the production efficiency based on mental fatigue. In addition, study3adopted the method of filed study instead of laboratory study which could not adequately simulate the real environment.Study4is the case application of study1, study2and study3. Based on the mental load, study4put forward the dynamic optimization of Standard Operating Procedure (SOP) which could help to find the balance point between the improvement of production efficiency and the relief of mental load.There are seven important conclusions based on the results of the four studies in this thesis.1) Emotion demonstrated a significant impact on the procuction efficiency. Concretely, it was the negative dimension of emotion but not the positive deimension of emotion could influence the production efficiency.2) With induced emoions, there was a significant Simon Effect for the reaction efficiency, i.e., the reaction time in the incongruent condition was longer than that in the congruent condition.3) Emotion directly influenced the cognitive process of the reaction efficiency, reflected by N2and P300. Compared to the induced neutral emotion, the induced negative emotion led to larger N2latency, larger N2amplitude and smaller P300amplitude for the following tasks.4) Emotion indirectly influenced the cognitive process of the reaction efficiency by modulating the level of Simon effect. It was reflected by P300and LRP. Compared to the induced neutral emotion, the induced negative emotion resulted in a larger discrepancy between the congruent and incongruent condtions in P300latency and LRP latency. That is to say, the induced netative emotion enhanced the cognitive level of Simon Effect.5) Mental fatigue influenced the production efficiency. The group with lower production efficiency demonstrated a higher mental fatigue which was reflected by EEG (theta, SMR, beta and gamma). More importantly, the significant difference of mental fatigue was found in the right brain for the standardization workstation but in the left brain for the non-standardization workstation.6) In order to improve the production efficiency based on humanization, an index of neuro-efficiency was put forward in our study. The index was based on the value engineering (VE) and mental load. It contained two sub-indicators, i.e., theta and VSMR.7) Based on the mental load, we put forward the dynamic optimization of SOP which could help to examine the improvement of production efficiency based on humanization in the perspective of motion analysis. That is, during the process of SOP optimaization, the motion adjustment would take the timely mental load into account.With the methods of questionnaire, neuroscience and physiology, we examined the impact of mental load on the production efficiency. There are four innovations which could be listed as follows:1) Our study made up the insufficient of previous researches and explored the impact of mental load on the production efficiency. Although previous studies realized that the mental load could influence people’s performance, they did not examine it in the background of production management. However, the production process demonstrated some special characters such as simple, repeat and noisy. Thus, whether the mental load could influence the production efficiency is still an important issue to be investigate, and that is one of our contributions and innovations.2) With the method of ERP, our study found the neural mechanism of how the mental load influenced the reaction efficiency. It helped us to understand the influencing mechanism not only from the macro level deeply into the micro level but also from the behavior level into the neuroscience level. With the comprehensive results of ERP and behavioral experiment together, this thesis helps us understand the influencing mechanism of mental load on the production efficiency more profoundly. This thesis also provides an exploration for the neural research of production efficiency.3) With the method of physiography, we carried out a field study to examine how the mental fatigue influenced the production efficiency. Taking the results of EEG (theta, SMR, beta and gamma) and EMG, this thesis found the physiological mechanism behind this influence. More importantly, our study put forward a neuro-efficiency based on the mental fatigue which made up the insufficient of previous indexes of production efficiency.4) Our study put forward a dynamic optimization of SOP based on the mental load. It merged the motion analysis and physiology technology together that the motion adjustment should take the timely mental load into account. Our thesis makes up the shortage of previous static optimization of SOP, and it reveals its significance in the practice.