Automatic inference on stable robotic assembly sequences based upon the evaluation of base assembly motion instability

Robotica ◽  
1993 ◽  
Vol 11 (4) ◽  
pp. 351-362 ◽  
Author(s):  
D.Y. Cho ◽  
C.K. Shinf ◽  
H.S. Chot
Keyword(s):  
Robotic Assembly ◽  
Fixture Design ◽  
Assembly Sequence ◽  
Inference Method ◽  
New Approach ◽  
Assembly Sequences ◽  
Crucial Information ◽  
Part Motion ◽  
Selection Of

SUMMARYThe consideration of part motion instability is crucial to the determination of assembly sequence since this affects the complexity of fixtures and dexterity of robots. This paper presents a new approach to the inference of robotic assembly sequences, taking into consideration the instability of base assembly motions. Based upon the evaluation of motion instability, the method generates stable assembly sequences by use of the precedence constraint inference method previously developed by the authors. An example assembly of a 10-part electrical relay is given to illustrate the concepts and procedure of the proposed scheme. The results show that the proposed method can be effectively utilized to generate stable assembly sequences, thus providing crucial information on the fixture design and selection of types of assembly robots.

scholarly journals Selection of Satellite Image Series for the Determination of Forest Pathology Dynamics Taking Into Account Cloud Coverage and Image Distortions Based on the Data Obtained from the Key Point Detector

2019 ◽  
Author(s):  
Евгений Трубаков ◽  
Evgeniy Trubakov ◽  
Андрей Трубаков ◽  
Andrey Trubakov ◽  
Дмитрий Коростелёв ◽  
...  
Keyword(s):  
Satellite Image ◽  
Forest Pathology ◽  
Acceptable Result ◽  
New Approach ◽  
Cloud Coverage ◽  
Point Detector ◽  
Automated Methods ◽  
Selection Of

Remote sensing of the earth and monitoring of various phenomena have been and still remain an important task for solving various problems. One of them is the forest pathology dynamics determining. Assuming its dependence on various factors forest pathology can be either short-term or long-term. Sometimes it is necessary to analyze satellite images within a period of several years in order to determine the dynamics of forest pathology. So it is connected with some special aspects and makes such analysis in manual mode impossible. At the same time automated methods face the problem of identifying a series of suitable images even though they are not covered by clouds, shadows, turbulence and other distortions. Classical methods of nebulosity determination based either on neural network or decision functions do not always give an acceptable result, because the cloud coverage by itself can be either of cirrus intortus type or insignificant within the image, but in case of cloudiness it can be the reason for wrong analysis of the area under examination. The article proposes a new approach for the analysis and selection of images based on key point detectors connected neither with cloudiness determination nor distorted area identification, but with the extraction of suitable images eliminating those that by their characteristics are unfit for forest pathology determination. Experiments have shown that the accuracy of this approach is higher than of currently used method in GIS, which is based on cloud detector.

scholarly journals A New Approach to Determine the Critical Path in Stochastic Activity Network

2014 ◽  
Vol 2014 ◽  
pp. 1-13
Author(s):  
Weng-Ming Chu ◽  
Koan-Yuh Chang ◽  
Chien-Yu Lu ◽  
Chang-Hung Hsu ◽  
Chien-Hung Liu ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Path Dependence ◽  
Critical Path ◽  
Stochastic Networks ◽  
Stochastic Network ◽  
New Approach ◽  
Path Index ◽  
Tracing Algorithm ◽  
Selection Of

The determination of the critical path (CP) in stochastic networks is difficult. It is partly due to the randomness of path durations and partly due to the probability issue of the selection of the critical path in the network. What we are confronted with is not only the complexity among random variables but also the problem of path dependence of the network. Besides, we found that CP is not necessarily the longest (or shortest) path in the network, which was a conventional assumption in use. The Program Evaluation and Review Technique (PERT) and Critical Path Index (CPI) approaches are not able to deal with this problem efficiently. In this study, we give a new definition on the CP in stochastic network and propose a modified label-correcting tracing algorithm (M-LCTA) to solve it. Based on the numerical results, compared with Monte Carlo simulation (MCS), the proposed approach can accurately determine the CP in stochastic networks.

A novel concatenation method for generating optimal robotic assembly sequences

2015 ◽  
Vol 231 (10) ◽  
pp. 1966-1977 ◽  
Author(s):  
MVA Raju Bahubalendruni ◽  
Bibhuti Bhusan Biswal
Keyword(s):  
Computer Aided Design ◽  
Cost Effective ◽  
High Energy ◽  
Robotic Assembly ◽  
Computational Time ◽  
Assembly Sequence ◽  
Design Environment ◽  
Assembly Sequences ◽  
Computer Aided ◽  
Assembly Sequence Generation

Selection of optimized assembly sequence is significantly essential to achieve cost-effective manufacturing process. This paper presents a novel efficient methodology to generate cost-effective feasible robotic assembly sequences though concatenation of parts. Part concatenation process will be followed with liaison predicate test and feasibility predicate test. A unique method called bounding box method is described to test the feasibility predicate efficiently in the computer-aided design environment. Assembly indexing technique is proposed to filter the redundant assembly subsets with high energy in order to minimize the computational time. The cost of collision free assembling operation is considered by the weight and distance traveled by the part in the assembly environment to join with the mating part. The method is successful in finding feasible optimal assembly sequence without ignoring any possible assembly sequence and found to be efficient in solving computer-aided assembly sequence generation. The correctness of the methodology is illustrated with an example.

AUTOMATIC COLLISION DETECTION FOR ASSEMBLY SEQUENCE PLANNING USING A THREE-DIMENSIONAL SOLID MODEL

2011 ◽  
Vol 10 (02) ◽  
pp. 277-291 ◽  
Author(s):  
ALFADHLANI ◽  
T. M. A. ARI SAMADHI ◽  
ANAS MA'RUF ◽  
ISA SETIASYAH TOHA
Keyword(s):  
Free Path ◽  
Collision Detection ◽  
Three Dimensional ◽  
Assembly Sequence Planning ◽  
Detection Methods ◽  
Assembly Sequence ◽  
Sequence Planning ◽  
Assembly Sequences ◽  
Geometrical Data ◽  
Selection Of

Assembly sequence planning of a product involves several steps, including generation of precedence constraints, generation of assembly sequences, and selection of assembly sequences. Generation and selection of assembly sequences should be able to guarantee the feasibility of assembly. Assembly will be feasible if there is no collision between components when assembled. Detection of collision-free path of assembly can be done in an automated way. There are a number of collision detection methods that have been developed, but the method requires a complicated process of data geometry analysis. This paper proposes a method for detecting a collision-free path of the assembly component in a more simple way. Geometrical data required, taken from the three-dimensional (3D) solid drawing in the form of stacked drawing in computer-aided design (CAD) systems. Retrieval of geometrical data of components and detection of the collision-free path of an assembly were done in an automated way, directly from the CAD system.

Generation of Optimized Robotic Assembly Sequence Using Immune Based Technique

2012 ◽  
Author(s):  
Bibhuti Bhusan Biswal ◽  
Sujit Kumar Pattanayak ◽  
Rabindra Narayan Mohapatra ◽  
Pramod Kumar Parida ◽  
Panchanand Jha
Keyword(s):  
Cost Effective ◽  
Robotic Assembly ◽  
Assembly Sequence ◽  
Artificial Immune ◽  
Optimal Sequence ◽  
Assembly Sequences ◽  
Assembly Operations ◽  
Assembly Constraints ◽  
Alternative Solutions ◽  
Economical Process

Automated assembly using robots is being gainfully used to enhance the process capabilities in the manufacturing world because of the fact that it is faster, more efficient, precise and cost effective process than any conventional mechanized process. However in assembly operations it is essential to determine the assembly sequence that is feasible, stable and faster so that an economical process can be evolved. Since robotic system is a cost intensive one it is necessary to find out the correct and optimal sequence with the constraints of the process in mind while dealing with assembled products with large number of parts. One of the most critical situations is to detect the best assembly sequence for products having large number of different alternative solutions. In this paper, a new methodology has been developed to find out the best robotic assembly sequence among the feasible robotic sequences. The feasible robotic assembly sequences have been generated based on the assembly constraints and later, the Artificial Immune System (AIS) has been implemented to find out the best assembly sequence.

Joint Positions and Robot Stability of the Omnidirectional Crawling Quadruped Robot

1999 ◽  
Vol 11 (6) ◽  
pp. 510-517 ◽  
Author(s):  
Xuedong Chen ◽  
◽  
Keigo Watanabe ◽  
Kiyotaka Izumi ◽  
◽  
...  
Keyword(s):  
Kinematic Chain ◽  
Quadruped Robot ◽  
Robot Kinematics ◽  
Stable Range ◽  
New Approach ◽  
Foot Placement ◽  
Quadruped Robots ◽  
Selection Of ◽  
Stable Area

Determination of joint positions, judgment of robot stability, and selection of the consequential swing leg are keys to crawling control for quadruped robots. We derive an efficient way to obtain actuation variables of joint positions to satisfy the gait for quadruped robots. By defining the statically stable area for foot placement, a new approach on analysis of robot stability is presented. Unlike conventionally, we avoid solving complicated direct robot kinematics as an overall kinematic chain and simultaneously show information on robot stability and the stable range of foot placement. Effectiveness is shown in practical crawling experiments.

Inference on robotic assembly precedence constraints using a part contact level graph

Robotica ◽  
1993 ◽  
Vol 11 (2) ◽  
pp. 173-183 ◽  
Author(s):  
D. Y. Cho ◽  
H. S. Cho
Keyword(s):  
Automatic Generation ◽  
Precedence Constraints ◽  
Geometric Reasoning ◽  
Precedence Constraint ◽  
Robotic Assembly ◽  
Path Finding ◽  
New Approach ◽  
User Query ◽  
Assembly Sequences

SUMMARYThis paper describes a new approach to the automatic generation of assembly precedence constraints for robotic assembly, using a part contact level graph. Since inference of precedence constraints is a prerequisite to generate assembly sequences of a product, much work has been done in this field. However, most of it has some limitations in that they use a cumbersome user query or time-consuming geometric reasoning. To cope with these problems, this paper utilizes three directional part contact level graphs which, in three orthogonal directions, contain the information on directional connections for each pair of mating parts. By using these graphs, an assembly precedence constraint is inferred in two steps: The first step infers a precedence constraint for each directional connection by applying the path-finding algorithm. Utilizing the precedence constraints thus obtained, the next step infers the precedence constraint for each part to be assembled with its base assembly. Examples are given to illustrate the concepts and procedure of the proposed scheme.

scholarly journals Complexation processes in “PbCl2-N2H4CS” aqueous solutions during deposition of lead sulphide films

2021 ◽  
Vol 23 (4) ◽  
pp. 543-547
Author(s):  
Victor N. Semenov ◽  
Vitaly V. Volkov ◽  
Natalia V. Pereslytskikh
Keyword(s):  
Aqueous Solutions ◽  
Coordination Compounds ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Lead Chloride ◽  
Lead Sulphide ◽  
New Approach ◽  
Complex Forms ◽  
Selection Of

In this study, we proposed a new approach to assessing the processes of complexation in aqueous solutions using the example of the interaction of lead chloride with thiourea. The goal of this study was the investigation of processes of complexation in “PbCl2-N2H4CS” aqueous solutions and determination of the regions of dominance of thiourea coordination compounds, which are precursors during the deposition of lead sulphide films.Based on the diagrams and cross section lines of equal fractions constructed in three-dimensional space, the regions of dominance of all complex forms existing in the studied solution were found. Such a graphic image is the most informative, since it allows selection of the concentration ranges of the predominance of certain coordination compounds, especially thiourea complexes, which are precursors during the deposition of lead sulphide films. It was shown that an increase in the concentration of N2H4CS led to an increase in the total fraction of thiourea complexes: for a twofold excess of N2H4CS its fraction was 0.25, for a threefold excess it was 0.35, for a fourfold excess it was 0.5, for a fivefold excess it was 0.7.

Generation of robotic assembly sequences with consideration of line balancing using simulated annealing

Robotica ◽  
1997 ◽  
Vol 15 (6) ◽  
pp. 663-673 ◽  
Author(s):  
D.S. Hong ◽  
H.S. Cho
Keyword(s):  
Simulated Annealing ◽  
Energy Function ◽  
Idle Time ◽  
Robotic Assembly ◽  
Line Balancing ◽  
Assembly Sequence ◽  
Assembly Cost ◽  
Assembly Sequences ◽  
Minimum Number ◽  
Assembly Constraints

An assembly sequence is considered to be optimal when the sequence satisfies assembly constraints and yields the minimum assembly cost. While, a line balancing solution is considered to be optimal when the solution has the minimum idle time of the line, i.e. the minimum number of workstations for a given cycle time. Although optimal assembly sequences are generated without considering line balancing, they may not guarantee the minimum number of workstations. In such case, additional cost should be required to accommodate the increased number of workstations. Therefore, it is essential to consider line balancing in the generation of cost-effective assembly sequences. To generate such line-balanced assembly sequences for robotic assembly, this paper treats a single-model and deterministic (SMD) assembly line balancing (ALB) problem, and proposes a new method using a simulated annealing. In this method, an energy function is derived in consideration of the satisfaction of assembly constraints, and the minimization of assembly cost and the idle time. Then, the energy function is iteratively minimized and occasionally perturbed by a simulated annealing. When no further change in energy occurs, a solution of assembly sequence with consideration of line balancing is finally obtained. To show the effectiveness of the proposed scheme, case studies are presented for industrial products such as an electrical relay and an automobile alternator.

Optimal robotic assembly sequence planning using stability graph through stable assembly subset identification

2019 ◽  
Vol 233 (15) ◽  
pp. 5410-5430 ◽  
Author(s):  
G Bala Murali ◽  
BBVL Deepak ◽  
MVA Raju ◽  
BB Biswal
Keyword(s):  
Research Work ◽  
Search Space ◽  
Assembly Sequence Planning ◽  
Robotic Assembly ◽  
Planning Problem ◽  
Assembly Sequence ◽  
Sequence Planning ◽  
Fitness Value ◽  
Assembly Sequences ◽  
Stability Graph

Assembly sequence planning is one of the multi-model optimization problems, in which more than one objective function has to be optimized at a time to obtain the quality assembly sequence. Moreover obtaining the feasible sequences from the possible finite set of sequences is a difficult task as the assembly sequence planning problem is N-P hard combinatorial problem. To solve the assembly sequence planning problem, researchers have developed various techniques to obtain the optimum solution. The developed methodologies have many drawbacks like struck at local optima, poor performance, huge search space and many more. To overcome these difficulties, the current research work aims to use stability graph to generate stable assembly subsets for obtaining the optimum assembly sequences. In the proposed methodology, to reduce the search space and to obtain the quality assembly sequences, stability graph is considered. Moreover, the fitness of assembly subsets is evaluated according to the user weights at each level before proceeding to the higher levels. Due to this, the higher fitness value subsets are eliminated at each stage by which time of execution will reduce enormously. The proposed methodology has implemented on various industrial products and compared the results with the various well-known algorithms.

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