The learning curve quantifies the phenomenon of performance improvement in repetitive assembly,and is widely used in enterprise management as an effective management tool.However,in the long-term monotonous repeatition assembly,the operator is prone to negative emotions such as boredom and drowsiness,leading to mental fatigue and impairing production efficiency.In addition,in the current multi-variety and small-batch production,the increase in the complexity of the assembly line brings a large working memory burden to the operator,causing the increase of mental workload,which is not conducive to production.It is worth noting that the transfer effect based on similarity can promote learning process and reduce learning costs.Therefore,how to motivate the operator to maintain the learning effect in the long-term repeatition assembly and use the promotion effect of the migration effect to improve the production efficiency is an urgent problem to be solved.Since the learning and migration effects are essentially dependent on working memory,it is necessary to investigate the changes in mental workload of light assembly operators to find effective ways to alleviate the high mental load of operators and achieve sustainable high efficiency through the neural mechanism behind it.Based on the empirical research of the enterprise,this study investigated the operators’mental workload from the perspective of learning effect and migration effect,and simulated the light assembly operation in the laboratory environment,and adopted the research method of neuro-ergonomics-near-infrared optics.Brain imaging technology(NIRS)evaluated the operator’s mental load.32 unversity students participated in the experiment.According to the conceptual theory of learning and transfer effect,the single product repetitive task and the similar product mixed flow task were designed,and the Lego car model was selected as the assembly object.At the same time,the blood oxygen concentration of pre-frontal area was monitored by near-infrared optical brain imaging(NIRS).During the experiment,the concentration of oxygenated hemoglobin(O2Hb)and the concentration of deoxygenated hemoglobin(HHb)were collected to reflect the operators’mental workload changes during the assembly process.The experimental results show that due to the existence of learning effect,the operator’s behavioral performance is gradually improved in repetitive assembly task,but the mental workload increases with the improvement of performance during the whole operation process.Moreover,the high mental workload status has an impact on the product completion rate in the standard operation stage.In the mixed flow operation,the operators’experience has an impact on the mental workload.The higher the similarity between the products produced after the current production,the more helpful to reduce the mental load of the operator for the current task.Compared with repetitive tasks,mixed-flow tasks help to relieve the high mental workload level.On the basis of experimental research,this paper further studies the influence of learning rate and fatigue cumulative rate on production performance by constructing the learning curve model under fatigue.The fatigue recovery model is embedded into the learning curve through the maximum endurance time.Through the numerial analysis,it is found that the increase of the learning rate contributes to the improvement of production performance;the increase of fatigue will result in the decrease of production performance.This study applied advanced techniques of neuro-ergonomics to investigate light assembly operators’mental workload based on learning and transfer effect,and combined with the model to deeply investigate the impact of factors such as learning rate on production performance.Research conclusion can help to provide theoretical basis and scientific guidance for production organization activities such as employee training and job scheduling. |