scholarly journals A Feedrate Planning Method for the NURBS Curve in CNC Machining Based on the Critical Constraint Curve

2021 ◽  
Vol 11 (11) ◽  
pp. 4959
Author(s):  
Peng Guo ◽  
Yijie Wu ◽  
Guang Yang ◽  
Zhebin Shen ◽  
Haorong Zhang ◽  
...  
Keyword(s):  
Planning Method ◽  
Cnc Machining ◽  
Arc Length ◽  
Kinematic Constraint ◽  
Nurbs Curve ◽  
Planning Strategy ◽  
Feedrate Planning ◽  
Curvature Constraint ◽  
Planning Methods ◽  
The Relationship

The curvature of the NURBS curve varies along its trajectory, therefore, the commonly used feedrate-planning method, which based on the acceleration/deceleration (Acc/Dec) model, is difficult to be directly applied in CNC machining of a NURBS curve. To address this problem, a feedrate-planning method based on the critical constraint curve of the feedrate (CCC) is proposed. Firstly, the problems of existing feedrate-planning methods and their causes are analyzed. Secondly, by considering both the curvature constraint and the kinematic constraint during the Acc/Dec process, the concept of CCC which represents the relationship between the critical feedrate-constraint value and the arc length is proposed. Then the CCC of a NURBS curve is constructed, and it has a concise expression conforming to the Acc/Dec model. Finally, a feedrate-planning method of a NURBS curve based on CCC and the Acc/Dec model is established. In the simulation, a comparison between the proposed method and the conventional feedrate-planning method is performed, and the results show that, the proposed method can reduce the Acc/Dec time by over 40%, while little computational burden being added. The machining experimental results validate the real-time performance and stability of the proposed method, and also the machining quality is verified. The proposed method offers an effective feedrate-planning strategy for a NURBS curve in CNC machining.

scholarly journals Morphological Aspects of Ciliary Motility

1967 ◽  
Vol 50 (6) ◽  
pp. 241-258 ◽  
Author(s):  
Peter Satir
Keyword(s):  
The Other ◽  
Radius Of Curvature ◽  
Arc Length ◽  
Apparent Displacement ◽  
Shaft Length ◽  
Ciliary Motility ◽  
Morphological Aspects ◽  
Circular Arcs ◽  
The Relationship

In Elliptio complanatus lateral cilia, two distinct patterns of filament termination can be discerned. In one case, all nine filaments are present and all are single; in the second, at least one filament is missing but doublets are still present. These probably represent different configurations within one cilium in different stroke positions; to get from one to the other, some peripheral filaments must move with respect to others. The data are consistent with the hypothesis that the filaments themselves do not change length, but rather slide past one another to accommodate increasing curvature. The bent regions of the cilium are in the form of circular arcs. In a few cases, apparent displacement of filaments at the tip (Δl) can be shown to be accounted for if we assume that all differences are generated within these arcs. The displacement per degree of bend is 35 A. Regions of bent arc are initially confined to the base of the cilium but move up the shaft as straight regions appear below them. From the relationship between arc length and radius of curvature, a shaft length that is the unit that initially bends and slides may be defined. Quantal displacements of the length of one 14S dynein may perhaps occur at sites between filaments at opposite sides of such a unit as sliding occurs.

Research and Application of the Power Network Planning Methods Oriented to the Clustered City Planning

2013 ◽  
Vol 448-453 ◽  
pp. 2636-2641
Author(s):  
Hai Long Bao ◽  
Chen Fang ◽  
Jian Lin Yang ◽  
Qiang Yin
Keyword(s):  
Transmission Lines ◽  
City Planning ◽  
Network Planning ◽  
Power Network ◽  
Metropolitan Regions ◽  
Planning Strategy ◽  
Planning Scheme ◽  
Planning Methods ◽  
Functional Orientation ◽  
Power Network Planning

As the urbanization of cities is rapidly developing in China, metropolitan regions establish the clustered power network planning scheme on the background of the clustered city planning of the adjacent areas. Base on the functional orientation and difference of clusters, as well as the theory of hierarchical clustered city planning, the article puts forward the power network planning thoughts and methods. As cluster becomes a planning unit, the load density method is applied in the differential load forecast and the location of substations as well as the path of transmission lines is selected with the thoughts of separation according to different layers and areas. And then, the results will be compared and verified with the planning scheme of the other clustered cities which have the similar function orientation and planning strategy. Finally, the planning methods will be standardized. The application in the power network of Cluster of Livable Education City in Zhengzhou has proved that the methods and steps of the power planning method proposed is able to meet the demand of the network development under the situation of the rapid growth of load.

scholarly journals THE GOVERNMENT'S INTERNAL AUDIT PLANNING STRATEGY IN PREVENTING CORRUPTION IN THE PROCUREMENT SECTOR IN THE ERA OF DISRUPTION

2020 ◽  
Vol 5 (1) ◽  
pp. 11
Author(s):  
Mustafa Kamal ◽  
Nasarudin Nasarudin
Keyword(s):  
Government Regulation ◽  
Swot Analysis ◽  
Internal Audit ◽  
Relationship Matrix ◽  
Planning Strategy ◽  
Task Forces ◽  
Audit Planning ◽  
The Relationship ◽  
Internal Supervision

This study aims to disclose not only the APIP's internal audit planning strategy in accordance with the mandate of the SAAIPI 2014, Law 30/2014, Law 23/2014, Government Regulation 60/2008, Presidential Regulation 16/2018, Presidential Regulation 54/2018, but also the synergy strategy among APIP, LKPP and APH in preventing corruption in the procurement sector. The research method used is a qualitative method with the literature studies, surveys, and retrospective studies. The results show that the mandate of internal supervision can be identified through the relationship matrix between SAAIPI 2014 and several regulations. The strategy in the synergy of supervision planning conducted by APIP, LKPP and APH can be determined through a SWOT analysis of the role of APIP. There are 4 choices of strategies for optimizing the role of APIP. APIP that has a capability score of 3 can use the SO and ST strategies. Whereas APIP that has capability scores of 1 and 2 can use the WO and WT strategies. Whole of Government can be built by APIP, APH and LKPP, either in the form of coordination between institutions, the formation of task forces, or social coalitions.

A Review of Path Planning Method for Mobile Robot

2014 ◽  
Vol 1030-1032 ◽  
pp. 1588-1591 ◽  
Author(s):  
Zong Sheng Wu ◽  
Wei Ping Fu
Keyword(s):  
Path Planning ◽  
Mobile Robot ◽  
Optimal Path ◽  
Grid Method ◽  
Field Method ◽  
Planning Method ◽  
Artificial Potential Field ◽  
Planning Methods ◽  
Basic Ideas ◽  
Artificial Potential Field Method

The ability of a mobile robot to plan its path is the key task in the field of robotics, which is to find a shortest, collision free, optimal path in the various scenes. In this paper, different existing path planning methods are presented, and classified as: geometric construction method, artificial intelligent path planning method, grid method, and artificial potential field method. This paper briefly introduces the basic ideas of the four methods and compares them. Some challenging topics are presented based on the reviewed papers.

A Multi-Agent Based Tool Path Planning Method for STEP-NC Compliant Milling

2010 ◽  
Vol 97-101 ◽  
pp. 3382-3386 ◽  
Author(s):  
Juan Du ◽  
Xian Guo Yan ◽  
Zhi Chen
Keyword(s):  
Path Planning ◽  
Tool Path ◽  
Data Transfer ◽  
Planning Method ◽  
Cnc Machining ◽  
Distributed Artificial Intelligence ◽  
Tool Path Planning ◽  
Machining Processes ◽  
Nc Program ◽  
Multi Agent

Today a new model of data transfer between CAD/CAM systems and CNC machines, called STEP-NC, is being developed by the ISO technical Committees. It overcomes the shortcomings of ISO 6983 by specifying machining processes rather than machine motion, using the object-oriented concept of working step. Although the STEP-NC contains abundant geometry information of part and associated process parameters, the tool path is general not included in the STEP-NC program. So before the beginning of the STEP-NC-compliant CNC machining, the tool path should be firstly designed. By analyzing the characteristic of STEP-NC data model for milling, a working step-oriented tool path planning method for milling was proposed in this paper, and the distributed artificial intelligence methods, namely collaborative multi-agent was employed to accomplish tool path planning. Firstly a multi-agent architecture was constructed to allow multiple agents to work cooperatively to realize automation of tool path planning, and then, the function of every kind of agent and the communication between the agents were all described in detail. At last, one test component was designed and simulated to demonstrate the capabilities of this research in the paper.

How to Use Information Technology Effectively to Achieve Business Objectives

2012 ◽  
pp. 19-35
Author(s):  
Antonio Goncalves ◽  
Natália Serra ◽  
José Serra ◽  
Pedro Sousa
Keyword(s):  
Information Technology ◽  
Software Development ◽  
Enterprise Architecture ◽  
Planning Strategy ◽  
The Business Cycle ◽  
High Level ◽  
Architecture Development ◽  
The Relationship ◽  
Dynamic Alignment

In this chapter the authors show, by using a case study, how it is possible to achieve the alignment between business and Information Technology (IT). It describes several phases of project development, from planning strategy, enterprise architecture, development of businesses supporting tools and keeping dynamic alignment between the business and the IT. The authors propose a framework, framed under an enterprise architecture that guarantees a high level of response to the applications development or configuration as improves its alignment to business by solving some limitations of traditional software development solutions namely: difficulty in gathering clients requirements, which should be supported by the applications; difficulty to connect the organisation processes used to answer the client, which must also be integrated in the applications and the difficulty to develop the applications that can follow the business cycle. To test the approach, this was applied to a real case study consisting in the configuration of an application that manages the relationship with the clients.

NURBS Curve Fitting Based on Arc Centripetal Parameterization for Tool Path Generation

2013 ◽  
Vol 274 ◽  
pp. 121-123 ◽  
Author(s):  
Cun Guang Yu
Keyword(s):  
Curve Fitting ◽  
Tool Path ◽  
Nc Machining ◽  
Tool Path Generation ◽  
Sculptured Surface ◽  
Arc Length ◽  
Tool Path Planning ◽  
Nurbs Curve ◽  
Location Data ◽  
Cutter Location Data

NURBS curve fitting is used for tool path planning for sculptured surface NC machining. The cutter location data is parameterized by equal chord arc length parameterization, and Centripetal Parameterization is improved. It is not only more approach to curves nature equation in theory, but also closer to the interpolated curves in actual fitting. It is directly to reflect the curvature of curves of cutter location in NC machining.

Region based Efficient CNC Machining using Point Cloud Data

2020 ◽  
pp. 1-35
Author(s):  
Mandeep Dhanda ◽  
Aman Kukreja ◽  
Sanjay Pande
Keyword(s):  
Path Planning ◽  
Surface Quality ◽  
Point Cloud ◽  
Tool Path ◽  
Cnc Machining ◽  
Real Surface ◽  
Tool Path Planning ◽  
Machining Time ◽  
Cloud Data ◽  
Planning Strategy

Abstract This paper presents an efficient tool path planning strategy for three-axis CNC machining using curvature based segmentation (CBS) of freeform surface from its representation in the form of a point cloud. Curvature parameters estimated over the point data are used to partition the surface into convex, concave, and saddle like regions. Grid based adaptive planar tool path planning strategy is developed to machine each region separately within its boundaries. In addition to the region by region machining, strategy to stitch the obtained regions is also developed to minimize the tool lifts and tool marks. The developed region based tool path planning strategy is compared with the point cloud based adaptive planar strategy, iso-scallop strategy and commercial software for parts with various complexities. The result shows significant improvement in terms of performance parameters viz. machining time, tool path length and code length while maintaining the desired part surface quality. The proposed method is also tested by machining a real surface and analyzing its surface quality.

Adaptive Tool Path Planning Strategy for 5-Axis CNC Machining of Free Form Surfaces

2019 ◽  
Author(s):  
Hrishikesh Mane ◽  
S. S. Pande
Keyword(s):  
Tool Path ◽  
Cnc Machining ◽  
Memory Storage ◽  
Free Form ◽  
Cnc Machine ◽  
Planning Strategy ◽  
Part Quality ◽  
Tool Paths ◽  
Path Topology ◽  
Free Form Surfaces

Abstract This paper presents a curvature based adaptive iso-parametric strategy for the efficient machining of free form surfaces on 5-axis CNC machine using the flat end mill tool. One iso-parametric boundary of the surface is selected as the initial tool path. Set of cutter contact (CC) points are chosen adaptively on the initial tool path considering desired profile tolerance. Adjacent iso-parametric tool paths are computed adaptively based on the scallop height constraint unlike the traditional iso-parametric approach. The path topology is post-processed to generate the part program for 5-axis CNC machine in ISO format. The system was rigorously tested for various case studies by comparing the results with the traditional 5-axis iso-parametric tool path strategy, iso-scallop strategy and iso-planar strategy of a commercial software. Our system was found to generate efficient tool paths in terms of part quality, productivity and memory storage compared to the conventional strategies.

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