Research On Ergonomic Indexes Of CNC Machine Tools Based On Simulation And Electromyography Experiment

The processing quality of domestic CNC machine tools has gradually reached the international advanced level,but it still has some deficiencies in human machine performance compared with some foreign machine tools.This paper starts with the ergonomics design,ergonomics evaluation and ergonomic index research methods of numerical control machine tools.Combining the man-machine-environment index system of numerical control machine tools,the indicators are classified according to the characteristics of the indicators and the corresponding index research methods and evaluation models are given.Among them,most of the indicators included in the safety and pleasantness of the man-machine indicators of CNC machine tools,as well as the machine-environment indicators,can be studied through questionnaire surveys,expert judgments,and theoretical analysis methods,and have already been studied in the project research report.A more complete and detailed explanation.Therefore,this article focuses on the study of ergonomic indicators such as visibility,accessibility,operating comfort,operating force,and fatigue damage protection of CNC machine tools using Jack simulation software and surface electromyography(sEMG)equipment.Provide technical support for ergonomic design,evaluation and optimization of CNC machine tools.Specific content includes:(1)Refer to the ergonomic index system of CNC machine tools at home and abroad and related ergonomic standards to classify the ergonomic indicators of CNC machine tools.Refer to the domestic and foreign literature on the research methods of ergonomic indicators,and summarize the index research methods into questionnaire survey,expert judgment,ergonomic analysis(theoretical analysis,simulation and experiment)and other methods.According to the specific content of the indicators and the requirements of the ergonomic indicators,the appropriate research methods are selected.Based on the above research,the evaluation models of the ergonomic indicators of CNC machine tools are given.(2)Combining with the three-dimensional model of CNC machine tools,ergonomic simulation software Jack is picked for simulation analysis.Learning about the simulation mechanism of simulation software,relevant algorithms,parameter settings,posture adjustment and other simulation points,the indicators related to the visibility,accessibility,and ease of operation of CNC machine tools were analyzed.Through the case analysis of the machine tool involved in the project to evaluate the indicators,and identify the causes of human factors caused by the lack of support for ergonomic optimization.(3)Acquire the surface electromyography(sEMG)signal that characterizes the functional status of the human nerve and muscle,and use experimental methods to study the operating force and cumulative fatigue injury indicators.According to the experimental specification and purpose,the muscle activity sEMG signals of human beings in partial postures were recorded when operating the machine,and the common time domain,frequency domain,and JASA data processing methods were used to extract and study the surface EMG signals.Taking the trapezius,biceps brachii,and erector spinae muscles as examples,the muscle activity status during operation was recorded,and the operating force and cumulative fatigue damage indicators were visually evaluated.This paper summarizes the research methods of ergonomic indicators for domestic CNC machine tools,and proposes a single indicator evaluation model according to the indicators research methods and ergonomic requirements,which will help improve the objectivity of ergonomic evaluation,thereby improving the human-machine performance of CNC machine tools,and enhancing their international competitiveness.It can also provide reference for ergonomic optimization of CNC machine tools.