针对制约众包模式健康发展过程中的人才抉择问题,以服装企业产品生产信息化的发展现状和趋势为依据,通过访谈50位服装版师,分析版师主要职责,总结企业绩效评价,建立服装版师人才多指标评价体系。该体系运用熵权法确定服装版师人才指标...针对制约众包模式健康发展过程中的人才抉择问题,以服装企业产品生产信息化的发展现状和趋势为依据,通过访谈50位服装版师,分析版师主要职责,总结企业绩效评价,建立服装版师人才多指标评价体系。该体系运用熵权法确定服装版师人才指标的权重,采用TOPSIS(technique for order preference by similarity to ideal solution)多指标决策算法对服装版师人才完成任务的能力进行评估并排序。展开更多
In this paper,two new interpolation algorithms for CNC machining along curved tool pathes are proposed:a time-optimal interpolation algorithm under chord error,feedrate,and tangential acceleration bounds,and a greedy ...In this paper,two new interpolation algorithms for CNC machining along curved tool pathes are proposed:a time-optimal interpolation algorithm under chord error,feedrate,and tangential acceleration bounds,and a greedy interpolation algorithm under the chord error and tangential jerk bounds.The key idea is to reduce the chord error bound to a centripetal acceleration bound which leads to a velocity limit curve,called the chord error velocity limit curve.Then,the velocity planning is to find the proper velocity curve governed by the acceleration or jerk bounds "under" the chord error velocity limit curve.For two types of simple tool pathes,explicit formulas for the velocity curve are given and the methods are implemented in commercial CNC controllers.展开更多
Tool path generation is a fundamental problem in 5-axis CNC machining, which consists of tool orientation planning and cutter-contact(CC) point planning. The planning strategy highly depends on the type of tool cutter...Tool path generation is a fundamental problem in 5-axis CNC machining, which consists of tool orientation planning and cutter-contact(CC) point planning. The planning strategy highly depends on the type of tool cutters. For ball-end cutters, the tool orientation and CC point location can be planned separately;while for flat end cutters, the two are highly dependent on each other. This paper generates a smooth tool path of workpiece surfaces for flat end mills from two stages: Computing smooth tool orientations on the surface without gouging and collisions and then designing the CC point path. By solving the tool posture optimization problem the authors achieve both the path smoothness and the machining efficiency. Experimental results are provided to show the effectiveness of the method.展开更多
Curve interpolation with B-spline is widely used in various areas. This problem is classic and recently raised in application scenario with new requirements such as path planning following the tangential vector field ...Curve interpolation with B-spline is widely used in various areas. This problem is classic and recently raised in application scenario with new requirements such as path planning following the tangential vector field under certified error in CNC machining. This paper proposes an algorithm framework to solve Hausdorff distance certified cubic B-spline interpolation problem with or without tangential direction constraints. The algorithm has two stages: The first stage is to find the initial cubic B-spine fitting curve which satisfies the Hausdorff distance constraint;the second stage is to set up and solve the optimization models with certain constraints. Especially, the sufficient conditions of the global Hausdorff distance control for any error bound are discussed, which can be expressed as a series of linear and quadratic constraints. A simple numerical algorithm to compute the Hausdorff distance between a polyline and its B-spline interpolation curve is proposed to reduce our computation.Experimental results are presented to show the advantages of the proposed algorithms.展开更多
文摘针对制约众包模式健康发展过程中的人才抉择问题,以服装企业产品生产信息化的发展现状和趋势为依据,通过访谈50位服装版师,分析版师主要职责,总结企业绩效评价,建立服装版师人才多指标评价体系。该体系运用熵权法确定服装版师人才指标的权重,采用TOPSIS(technique for order preference by similarity to ideal solution)多指标决策算法对服装版师人才完成任务的能力进行评估并排序。
基金supported by a National Key Basic Research Project of China under Grant No.2011CB302400the National Natural Science Foundation of China under Grant No.60821002
文摘In this paper,two new interpolation algorithms for CNC machining along curved tool pathes are proposed:a time-optimal interpolation algorithm under chord error,feedrate,and tangential acceleration bounds,and a greedy interpolation algorithm under the chord error and tangential jerk bounds.The key idea is to reduce the chord error bound to a centripetal acceleration bound which leads to a velocity limit curve,called the chord error velocity limit curve.Then,the velocity planning is to find the proper velocity curve governed by the acceleration or jerk bounds "under" the chord error velocity limit curve.For two types of simple tool pathes,explicit formulas for the velocity curve are given and the methods are implemented in commercial CNC controllers.
基金supported by the National Natural Science Foundation of China under Grant No.11688101,61872332Beijing National Natural Science Foundation under Grant No.Z190004+1 种基金National Center for Mathematics and Interdisciplinary SciencesYouth Innovation Promotion Association of the Chinese Academy of Sciences。
文摘Tool path generation is a fundamental problem in 5-axis CNC machining, which consists of tool orientation planning and cutter-contact(CC) point planning. The planning strategy highly depends on the type of tool cutters. For ball-end cutters, the tool orientation and CC point location can be planned separately;while for flat end cutters, the two are highly dependent on each other. This paper generates a smooth tool path of workpiece surfaces for flat end mills from two stages: Computing smooth tool orientations on the surface without gouging and collisions and then designing the CC point path. By solving the tool posture optimization problem the authors achieve both the path smoothness and the machining efficiency. Experimental results are provided to show the effectiveness of the method.
基金partially supported by the National Key Research and Development Program of China under Grant No. 2020YFA0713703the National Science Foundation of China under Grant Nos. 11688101, 12371384+1 种基金12271516the Fundamental Research Funds for the Central Universities。
文摘Curve interpolation with B-spline is widely used in various areas. This problem is classic and recently raised in application scenario with new requirements such as path planning following the tangential vector field under certified error in CNC machining. This paper proposes an algorithm framework to solve Hausdorff distance certified cubic B-spline interpolation problem with or without tangential direction constraints. The algorithm has two stages: The first stage is to find the initial cubic B-spine fitting curve which satisfies the Hausdorff distance constraint;the second stage is to set up and solve the optimization models with certain constraints. Especially, the sufficient conditions of the global Hausdorff distance control for any error bound are discussed, which can be expressed as a series of linear and quadratic constraints. A simple numerical algorithm to compute the Hausdorff distance between a polyline and its B-spline interpolation curve is proposed to reduce our computation.Experimental results are presented to show the advantages of the proposed algorithms.
