【作者】 王永志；

【导师】 陈传海；

【作者基本信息】 吉林大学 ， 工程硕士（专业学位）， 2023， 硕士

【摘要】 工业机器人的研发水平和应用能力已成为衡量一个国家制造业发展水平的重要标志。目前我国已成为全球最大的工业机器人消费国,但是国产工业机器人的市场占有率低,尤其高端工业机器人的市场长期被国外产品垄断,其主要原因是国产工业机器人可靠性水平较低。开展可靠性评估是产品可靠性设计和运行维护的基础,对用户的使用具有重要指导意义。由于工业机器人属于高可靠性、长寿命产品,难以在短时间内获取足够量的用于可靠性评估的故障数据。因此,本文以工业机器人性能退化为切入点,基于加速退化试验和建模技术,对工业机器人可靠性评估方法进行研究。论文主要研究内容如下:(1)选取性能退化指标,并制定测试方案。分析工业机器人的结构原理和故障模式,明确其性能退化原因,进一步对工业机器人关键部件开展FMECA(故障模式、影响及危害性分析),在此基础上确定工业机器人的主要性能测试指标;采用MD-H参数建模方法,建立工业机器人的正运动学模型,并求解其工作空间,在此基础上制定工业机器人性能退化指标的测试方案。(2)试验方案设计及试验平台开发。针对工业机器人试验样本少的问题,设计基于步进应力的加速退化试验;针对试验需求,开发用于工业机器人载荷模拟与性能退化指标测试的软、硬件平台;开展工业机器人基于步进应力的加速退化试验,并对试验数据进行处理。(3)建立工业机器人的加速退化可靠性模型。针对工业机器性能退化数据呈现非线性、随机性和测试点差异的特点,建立考虑测试点差异的非线性Wiener过程加速退化模型;针对模型参数给出了基于分步极大似然和贝叶斯的求解方法;根据首达失效时间概念,推导额定负载和确定阈值下的可靠度模型;通过蒙特卡洛仿真,验证所建模型的合理性和参数求解的准确性。(4)对工业机器人进行可靠性评估。分别利用重复位置精度退化数据和振动特征退化数据,开展基于一元性能退化指标的工业机器人可靠性评估;在此基础上,利用Copula函数建立考虑两性能退化指标相关性的二元可靠度模型,在边缘推断法求的指导下,求解模型中的参数;开展基于二元性能退化指标的工业机器人可靠性评估,并与不考虑两性能退化指标相关性的可靠性评估进行对比分析。更多还原

【Abstract】 The technical level of industrial robots is an important symbol to measure the development level of a country’s manufacturing industry.At present,China has become the world’s largest industrial robot consumer,but the market share of domestic industrial robots is low,especially the market of high-end industrial robots has been monopolized by foreign products for a long time,and the main reason is the low level of reliability of domestic industrial robots.Reliability assessment is the basis of product reliability design and operation and maintenance,and also has guiding significance for users’ use.Since industrial robots are highly reliable and long-life products,it is difficult to obtain sufficient amount of failure data for reliability assessment in a short period of time.Therefore,this paper takes the performance degradation of industrial robots as the entry point and investigates the reliability assessment methods of industrial robots based on accelerated degradation tests and modeling techniques.The main study work of this paper includes:(1)Select performance degradation indexes and develop a performance degradation index testing scheme.Analyze the structural principles and failure modes of industrial robots,clarify the causes of their performance degradation,further carry out FMECA on key components of industrial robots,and determine the main performance test indexes of industrial robots on this basis;use the MD-H parameter modeling method to establish the positive kinematic model of industrial robots and solve their workspace,and develop the performance degradation indexes of industrial robots on this basis testing scheme.(2)Test program design and test platform development.In response to the problem of small test samples of industrial robots,we designed accelerated degradation tests based on step stress;developed software and hardware platforms for load simulation and performance degradation index testing of industrial robots in response to test demands;conducted accelerated degradation tests based on step stress of industrial robots and processed test data.(3)To establish an accelerated degradation reliability model for industrial robots.For the characteristics of industrial machine performance degradation data showing nonlinearity,randomness and test point differences,a nonlinear Wiener process accelerated degradation model considering test point differences is established based on the nonlinear Wiener process,and the unknown parameters in the model are solved by using the great likelihood and Bayesian methods;the reliability model under rated load and determined threshold is derived based on the concept of first reach failure time;the reliability model is validated by Monte Carlo simulation is performed to verify the rationality of the proposed model and the accuracy of the parameter solutions.(4)Reliability assessment of industrial robots.The reliability assessment of industrial robots based on one-dimensional performance degradation indexes was carried out by using repeated position accuracy degradation data and vibration characteristic degradation data respectively;on this basis,a binary reliability model considering the correlation of two performance degradation indexes was established by using Copula function,and the Copula correlation parameters in the model were solved by using edge extrapolation method;the reliability assessment of industrial robots based on binary performance degradation indexes was carried out and compared with the reliability assessment without considering the correlation of two performance degradation indexes.The reliability assessment based on the binary performance degradation index is carried out and compared with the reliability assessment without considering the correlation between the two performance degradation indexes.更多还原