ASSEMBLY AND DISASSEMBLY AN OVERVIEW AND FRAMEWORK FOR

ASSEMBLY AND DISASSEMBLY: AN OVERVIEW AND FRAMEWORK FOR COOPERATION REQUIREMENT PLANNING WITH CONFLICT RESOLUTION in Journal of Intelligent and Robotic Systems Vol: 37, 2003. S. Y. NOF and J. CHEN Presented By – Ajit Vaze

Assembly Example

Assembly Building together certain individual parts , subassemblies and substances in a given quantity and within a given time period. Disassembly All processes that break down the structure of geometrically defined bodies within a given time period.

Design for Assembly and Disassembly (DFAD) Considers issues that will affect assembly during the design procedure and the assembly’s lifecycles. Integrates the specific domain knowledge of manufacturing, design and decision-making Aims to reduce the cost of assembly and improve its quality.

DFAD Product simplification which leads to part’s cost reduction. Reduction in inventory Reduction in record keeping Improvement in material and production flow

Integration of AI in DFAD Need: Complexity of assembly and product design. Benefits: n Improved design quality with fewer errors. n Less training and expertise necessary for designers for utilizing CAD tools. n On-line advice on how to improve design work. n AI can reduce the cycle time of the design procedure.

Ways to introduce AI in DFAD Rule based knowledge systems KBS for interface with assembly CAD KBS for interface with facility design KBS for assembly and manufacturing design Constraint net knowledge systems. AI in assembly planning

AI in Assembly Planning Assembly knowledge representation Assembly sequence generation and planning Integrated assembly and task planning

Cooperation Requirement Planning (CRP)

Cooperation Requirement Planning (CRP) CRP- I : Applies assembly planning techniques to generate the cooperation measures for assembly tasks. CRP – II : Generates global assembly plan by applying best first search method.

Cooperation Requirement Planning (CRP) Interaction conflicts resolved by time delays, communication methods, or path modifications. Cooperation considered throughout the planning Minimal constraints on the plan for maximum flexibility. Generate plans that can be completed most effectively with the available equipments. Integrates assembly sequence planning with execution task planning.

Extended Framework for CRP (ECRP)

Extended Framework for CRP (ECRP) Introduction of following modules along with cooperation requirement planning : Conflict Resolution Module : Detects conflicts inside the CRP and solves the identified conflicts. Error Recovery Module : Checks the received error information and recovers from the error automatically.

Extended Framework for CRP (ECRP) ERROR RECOVERY n NEFUSER : Neural Fuzzy System for Error Recovery. n Recognition and recovery from different types of errors n Data supplied from touch or optical sensors n Data processed as on-line learning source.

NEFUSER

Extended Framework for CRP (ECRP) Conflict Resolution Possible types of conflicts: n Interference among machines n interference among material flow Effects of conflicts n Redesign of the facility and/or product n Regeneration of assembly execution plan

Mcr System Objectives n Automatic detection of potential conflicts n Automatic resolution of conflict n Prevention of future conflicts This system is incorporated in Facility Description Language (FDL). The resulting version is FDL-CR (Lara and Nof, 2001)

Mcr System

Mcr System Four typical conflict situations Conflict situation during layout design. Conflict during determination of product routing Conflict during selection and programming of robotic equipment Conflict during selection of visual sensors

Mcr System Five stages of conflict resolution Direct negotiation Incorporation of additional parties Third party mediation Persuasion Arbitration

Results Improved performance of method Computer based learning increased usefulness of the method Increased effectiveness of the facility design process Significant reduced cost

Results Expected Cost without Mcr (Unbounded Cost)

Results Expected Cost with Mcr (Bounded Cost)

Future Challenges Web-Enabled Assembly and Disassembly n n n Synchronous communication and manipulation of 3 -D part models on the Web Full integration of devices for assembly Web-based systems for decision making activities and conflict resolution

Future Challenges Micro assembly n n n Preparation of parts to be assembled Transportation of parts Positioning and fixing the finished system Connecting the parts Testing and measuring the finished system Integration of micro assembly with microproduct design and micro-robot design.

Questions? ? ? Thank You