Systematic forecast of human reliability in manual assembly operations in serial production

装配在德国经济中起着主导作用，特别是在附加值方面。根据产品特性的不同，装配操作占总生产时间的70%。近年来，随着产品生命周期的缩短和客户对质量要求的提高，对手工装配作业的规划过程的需求也在不断增加。质量计划的一个主要目标是创建强大的生产过程并减少生产中的错误数量。转移到人工装配过程领域，这意味着，除了掌握技术复杂性之外，还可以减少员工的人为错误概率。因此，早期发现质量关键操作是产生稳定和高效生产过程的关键因素。对生产过程弱点的评价通常局限于技术和经济领域。目前，人工装配过程的规划过程主要集中在时间调度的优化上。为此目的，装配计划人员通常使用预定时间系统来计算执行手动装配操作所需的时间。尽管在之前的项目MTQM中开发了第一个科学方法，但到目前为止，在操作实践中忽略了对装配操作中人的可靠性的系统考虑。在本研究项目中，将开发一种方法，该方法有可能系统地预测人工装配操作中的人为错误概率。开发过程的起点是先前项目MTQM的结果，也是通过使用预定时间的系统创建的过程分析。除了计算预定时间外，这些过程分析还用于通过确定单个任务项的提示运动值来评估人工装配操作的单个动作序列的复杂性和错误率。随着所获得的知识，一个系统的程序评估人力的可靠性在手工装配操作将开发。上述程序将基于任务分类法的专家系统，由于这个原因，它特别适合于所考虑的应用领域的某些特征。由于人工装配操作的人类可靠性受到学习曲线效应的强烈影响，因此在开发新方法时，还将检查员工经验的影响及其对所产生的错误概率的影响。由于对人工装配操作中人类可靠性的预期确定，装配计划人员将能够在生产开始之前实施必要的调整。有了这种方法，就可以避免在正在进行的操作中进行昂贵的重新设计。

Assembly plays a leading role in the German economy, especially in terms of added value. Depending on product characteristics assembly operations take up to 70 % of the total production time. In recent years, shorter product life cycles and increasing quality requirements of customers led to increasing demands also for the planning process of manual assembly operations.A major goal of quality planning deals with creating strong production processes and reducing the number of errors in production. Transferred to the field of manual assembly processes, this means, besides mastering the technical complexity, also to reduce the human error probability of the employee. The early detection of quality-critical operations therefore is a key element for generating stable and efficient production processes.The evaluation of weaknesses of the production process is usually limited to technical and economical fields. Currently, the planning process of manual assembly processes is primarily focused on an optimization of time scheduling. For this purpose, assembly planners generally use systems of predetermined times for calculating the time that is required to perform a manual assembly operation. Despite of first scientific approaches developed in the previous project MTQM a systematic consideration of human reliability in assembly operations so far is neglected in the operational practice.In this research project, a method will be developed that has the potential to predict human error probabilities in manual assembly operations systematically. The starting point of the development process are the results of the previous project MTQM and also process analyses created by using systems of predetermined times. In addition to the calculation of predetermined times, these process analyses are used to assess the complexity and thus also the error rate of individual sequences of action of manual assembly operations by determining cue motion values for individual task items. With the gained knowledge a systematic procedure for evaluating human reliability in manual assembly operations will be developed. The above mentioned procedure will be based on an Expert System For Task Taxonomy, which for this reason is especially adapted to the certain characteristics of the considered application field. As the human reliability of manual assembly operations is strongly affected by learning curve effects, the influence of experience of the employees and its impact on the amount of resulting error probabilities will also be examined while developing the new method. Due to the prospective determination of human reliability in manual assembly operations the assembly planner will be able to implement necessary adjustments already before start of production. With this procedure costly redesigns during ongoing operations can be avoided.