• Journal of Institute of Control, Robotics and Systems
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• v.6 no.6
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• pp.506-513
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• 2000

This paper proposes a path planning algorithm for dispensers to increase the productivity in printed circuit board assembly lines. We analyze the assembly sequence of the dispenser, and formulate it as an integer programming problem. The mathematical formulation can accomodate multiple heads and different types of heads through extended cost matrix. The TSP algorithms are then applied to the formulated problem to find the near-optimal solution. Simulation results are presented to verify the usefulness of the proposed scheme.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.3
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• pp.355-363
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• 2007

This paper presents a method of an automatic work time evaluation based on the verification of a disassemblability and assembly configuration. Even though a work time evaluation is an important field of concern for planning assembly lay-out, there are some limitations using cumbersome user query or approximated work time data without considering assembly condition. To overcome such restriction, this paper presents a method to mathematically verify assembly conditions based on the disassemblability, which is defined by the separability and stability cost. The separability cost represents a facility of the part disassembly operation, and the stability cost which represents a degree of the stability for the base assembly motion. Based upon the results, we propose a new approach of evaluating work time using neural networks. The proposed method provides an effective means of solving the work time evaluation problem and gives a design guidance of planning assembly lay-out in flexible manufacturing application. Example study is given to illustrate the concepts and procedure of the proposed schemes.

• Journal of Korean Institute of Industrial Engineers
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• v.31 no.3
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• pp.180-193
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• 2005

This paper deals with a multiobjective process planning problem of flexible assembly systems(FASs). The FAS planning problem addressed in this paper is an integrated one of the assignment of assembly tasks to stations and the determination of assembly routing, while satisfying precedence relations among the tasks and flexibility capacity for each station. In this research, we consider two objectives: minimizing transfer time of the products among stations and absolute deviation of workstation workload(ADWW). We place emphasis on finding a set of diverse near Pareto or true Pareto optimal solutions. To achieve this, we present a new multiobjective coevolutionary algorithm for the integrated problem here, named a multiobjective symbiotic evolutionary algorithm(MOSEA). The structure of the algorithm and the strategies of evolution are devised in this paper to enhance the search ability. Extensive computational experiments are carried out to demonstrate the performance of the proposed algorithm. The experimental results show that the proposed algorithm is a promising method for the integrated and multiobjective problem.

• Journal of Ocean Engineering and Technology
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• v.17 no.1
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• pp.67-71
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• 2003

This paper presents the use of an evert system to automate process planning of block assembly, a task that is usually completed manually. In order to determine the sequence of assembly operation, a search method guided by rules, such as merging of related operations, grouping of similar operations, and precedence rules based on know-hows and geometrical reasoning, is used. In this paper, the expert system developed is explained in detail regarding a global database, control strategies, and rule bases. For verification purposes, the evert system has been applied to simple examples. Since the rule bases are isolated from the inference engine in the developed system, it is easy to add more rules in the future.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.7
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• pp.656-662
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• 2008

A cost-function based on manipulability and compatibility is designed to determine assembly motions of two cooperating manipulators. Assembly motions are planned along the direction maximizing performance indices to improve control performance of the two manipulators. This paper proposes bimanual task compatibility by defining cost functions. The proposed cost functions are applied and compared to the bimanual assembly task. The problem is formulated as a constrained optimization considering assembly constraints, position of the workpieces, and kinematics and redundancy of the bimanual robot. The proposed approach is evaluated with simulation of a peg-in-hole assembly with an L-shaped peg and two 3-dof manipulators.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.4
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• pp.111-117
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• 1998

In order to increase productivity of an assembly system composed of multiple robots along a conveyer line, an efficient sequence planning is necessary because the assembly time is dependent upon the assembly sequence. In this paper, a two-robot assembly system is considered in which two robots operate simultaneously and transfer parts from the part feeders to the workpiece on the conveyer one by one. In this case, the distance from the feeder to the workpiece varies with time because the workpiece moves at a constant speed on the conveyer. Hence, the sequence programming is not a trivial problem. Also, the two robots may interfere with each other kinematically and dynamically due to the simultaneous operation, so the sequence should be programmed to avoid the interferences. In this paper, the task sequence optimization problem is formulated and is solved by employing the simulated annealing which has been shown to be effective for solving large combinatorial optimizations.

• IE interfaces
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• v.17 no.spc
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• pp.20-27
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• 2004

A flexible assembly system (FAS) is a production system that assembles various parts with many constraints and manufacturing flexibilities. This paper presents a new method for efficiently solving the integrated process planning and scheduling in FAS. The two problems of FAS process planning and scheduling are tightly related with each other. However, in almost all the existing researches on FAS, the two problems have been considered separately. In this research, an endosymbiotic evolutionary algorithm is adopted as methodology in order to solve the two problems simultaneously. This paper shows how to apply an endosymbiotic evolutionary algorithm to solving the integrated problem. Some evolutionary schemes are used in the algorithm to promote population diversity and search efficiency. The experimental results are reported.

• International Journal of Control, Automation, and Systems
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• v.4 no.1
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• pp.96-104
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• 2006

We propose a path planning method to improve the productivity of AOI (automated optical inspection) machines in PCB (printed circuit board) assembly lines. The path-planning problem is the optimization problem of finding inspection clusters and the visiting sequence of cameras to minimize the overall working time. A unified method is newly proposed to determine the inspection clusters and visiting sequence simultaneously. We apply a hybrid genetic algorithm to solve the highly complicated optimization problem. Comparative simulation results are presented to verify the usefulness of the proposed method.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.10
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• pp.972-976
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• 2015

The objective of this research is to verify the quantitative efficiency of a bimanual robotic task. Bimanual robots can realize dexterous and complicated motions using two cooperating arms. However, its motion planning and control method are not simple for implementing flexible tasks such as assembly. In this paper, the proposed motion planning method is used to find an optimal solution satisfying a designed cost function and constraints with regard to the kinematics and redundancy of the bimanual robot. The simulation results show that the lifetime of the manipulator can be changed by the proposed cost function consisting of angular velocity and angular acceleration of each joint in the same assembly task.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.637-638
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• 2009