Zoran Kunica DOPRINOS GENERIRANJU PLANOVA AUTOMATSKE MONTA

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ISATP03 - THE 5th IEEE INTERNATIONAL SYMPOSIUM
ON ASSEMBLY AND TASK PLANNING Session F4B
Production System Design
Development of a Design Procedure for Automatic
Assembly System
Zoran KUNICA, Ph.D., Assistant
Professor Professor Božo VRANJEŠ, Ph.D.
Ivona TOMIC, B.Sc.
Faculty of Mechanical Engineering and Naval
Architecture
University of Zagreb
Croatia
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CONTENT

• I. INTRO
• II. ASSEMBLY PLANNING TOOLS
• III. PLANNING SOFTWARE CONTENT
• IV. ASSEMBLY SYSTEM DESIGN APPROACH
  ASSUMPTIONS
• V. ASSEMBLY SYSTEM DESIGN AN EXAMPLE
• VI. FURTHER WORK

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I. INTRO

• Despite the significant advance in integration of
  engineering activities and
• technical systems, concurrent engineering
  approaches in integration of product
• design, assembly system design and assembly
  execution are still of pretty rare
• occurrence.
• Especially, CAD/CAE support for assembly system
  design is still underdeveloped.
• The goals of the research
• upgrading the planning methodology of automated
  assembly systems,
• development of the CAE tools for planning.
• In this paper, we have tried to identify the
  procedure appropriate to assembly
• system design.

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II. ASSEMBLY PLANNING TOOLS
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III. PLANNING SOFTWARE CONTENT

• DFA ASSEMBLY TECHNIQUES
• ASSEMBLY SYSTEM/WORKCELL DESIGN (including
  catalogues, CAD translators importers)
• DEFINITION OF POSITIONS
• PROGRAMMING
• PROGRAM OFF-LINE SIMULATION (COLLISION CHECK)
• PROGRAM DOWNLOAD TO ROBOT/STATION CONTROLLER
• PROGRAM EXECUTION
• LAYOUT OPTIMISATION
• PRODUCTION CYCLE OPTIMISATION
• FINANCIAL METRICS
• DIGITAL I/O AND WIRING DIAGRAMS

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Development approaches
CAD-based
Programming-based
Assembly-based
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IV. ASSEMBLY SYSTEM DESIGN APPROACH
ASSUMPTIONS

• The basis for assembly system design is
  appropriate ASSEMBLY PLAN, which
• defines
• assembly sequence,
• assembly paths,
• parts' positions (before and after assembly),
• assembly operations.
• Assembly paths and operations imply principal
  technical solutions of particular
• assembly devices (device type, number, kinematics
  and dimensions) within
• assembly system.
• The equipment devices, for assembly system is
  defined in three ways
• choosing among existing equipment,
• modification of the existing equipment,
• design of entirely new equipment.
• Devices are modelled interactively and
  automatically during CAD session,
• and using CAD libraries and catalogues, which
  possess parameterised design
• base of devices. The manufacturers or third party
  companies (Part Solutions)

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A concept of the assembly system development
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• a product -- an assembly, exists as CAD model
• assembly and disassembly are inverse issues
• a product is a virtual mechanism, that should be
  recognized during planning stage
• an assembly system is a complementary mechanism

AAssembly process/system planning
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An assembly planning environment should combine
tools distributed in two levels 1. pretools
within activities prior to assembly
planning, 2. assembly planning CAE component
(posttool) that follows product design process.
Assembly planning and activities of product
design
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Discrepancy in orientation natural orientation
of the part (A), technological orientation (B),
orientation required in a product (C)
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Origins of orientation definition
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Planning procedure should be analysed as a
combination of automatically and interactively
generated elements.
Example of definition of plan generation
parameters
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• Variants/variations of products

TThompson's examples of variations of living
organisms (1917)
Duerer's (1471-1528) examples of variations
of living organisms
 Two solutions of the same mechanism (Blanding,
1999)
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• Variations of assembly process

• The assembly process can be represented and
  modelled using generic structures generic
  plans.
• The structures show the space and time
  possibility of the assembly process realisation.

Some of the structures for a product with six
parts (Beneath the graphical presentation of each
structure the structures numerical code is
given.)
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• Variants of products initial orientation

xz horizontal plane
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Variants of parts layout
Line assembly (L 8639,487 mm)
.
Hi5
Rotary-table (D 1234,212 mm)
Hi4
z distance Hi5-Hi6 5924,22 mm
Hi2
Hi3
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Hi6
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Treatment of identical parts in a product
Disassembled product...
Without taking into account identical parts...
Taking into account identical (yellow) parts...
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Variants of equipments manufacturer
FANUC LR Mate 100i
AdeptSix 300
ABB IRB 140

• Variants... variants... etc. ...

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VI. ASSEMBLY SYSTEM DESIGN AN EXAMPLE

• A product assembly

Hi5
100 mm
Hi3
75 mm
Hi2
Hi7
75 mm
xz horizontal plane
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Disassembly simulation (sequence and paths,
and positions of parts before assembly)
Top view
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Variant I
There are four identical pneumatic cylinders. The
cylinders push parts from their positions before
assembly, towards required final positions, to
make the assembly. The cylinders are pretty
long, implying a larger necessary space. The
parts come in the assembly process in ordered
state -- magazines. Assembled product is removed
from the assembly spot by a murder hole.
Double acting cylinder DSNU-25-400P-A
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Variant II
Almost the same as the variant I. There are also
four identical cylinders, but of another type
with shorter strokes. In that way it was possible
to place parts closer to the assembly spot
(correction of position values obtained by
assembly plan). The cylinders in both variants
(I II) are chosen among many available, and
applicable to this specific situation.
Double acting cylinder DSW-32-P-B
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Variant III
The assembly system consists of four identical
manipulators, each containing two linear modules,
and having identical grippers. Additionally,
there is also a pneumatic cylinder for the part
Hi7. Three manipulators with their grippers
carry the parts to the required final positions.
The fourth manipulator takes the part Hi7 and
delivers it at the pneumatic cylinder, which
pushes the part in its final position within the
product. Since the manipulators have only two
DOFs, included pallets should be movable (two
DOFs).
Linear module HMP-20-400
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Parallel gripper HGP-35-10
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Variant IV
Vacuum gripper VAS-30-1/8-PUR
The variant IV is similar to the variant III,
except a robot equipped with a vacuum gripper is
added to the part Hi7, so the cylinder from the
variant III is obsolete.
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Variant V
The variant V is the enhancement of the variants
III and IV. The main difference -- three robots
(with four DOFs each) are used in the variant V,
instead of manipulators in the variants III and
IV. Consequently, movable pallets are no longer
needed.
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Variant VI
Three identical robots from the variant V are
replaced with one single robot. The savings in
equipment cost and space are obvious, but
assembly cycle will be longer.
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Variant VII
Only one single robot with four DOFs, will
assemble the whole product. Since the part Hi7
requires different gripper than the rest of the
parts, the assembly system should involve a
possibility of gripper change. Neglecting the
gripper change subsystem, the variant VII carries
further cutting of equipment and space costs.
However, the assembly cycle becomes longer.
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Variant Equipment Ranking criterion Ranking criterion Ranking criterion Ranking criterion ?
Variant Equipment Productivity, 60 Price, 25 Flexibility, 10 Space, 5 ?
I 4 pneumatic cylinders DSNU-25-400P-A, magazines, murder hole 4 5 3 4 4,15
II 4 pneumatic cylinders DSW-32-P-B, magazines, murder hole 5 5 3 5 4,8
III 4 manipulatorsgrippers, pneumatic cylinder, movable pallets, murder hole 3 3 4 1 3
IV 3 manipulatorsgrippers, robotvacuum gripper, 3 movable pallets, fixed pallet, fixed pallet for assembled products 3 2 5 3 2,95
V 4 robotsgrippers, 5 fixed pallets 3 1 5 2 2,65
VI 2 robotsgrippers, 5 fixed pallets 2 3 5 4 2,65
VII single robot, 2 grippers, five fixed pallets 1 4 5 5 2,35
Comparison of the assembly system variants
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VII. FURTHER WORK

• Detailed variant design of devices, including
• analysis and optimization of (dis)assembling
  paths (directions and lengths),
• simulation of assembly operations and assembly
  techniques (forces, deformable joints - snap
  fitting, ...).
• Implementation of assessment criteria.
• Automation of the design procedure.
• Experiments with concurrent generation of
  assembly plans and systems.
• Modelling of CE planning situations and roles
  (procedures, protocols and data sharing).
• Human planner's mental activities and behavior --
  conscience and non-conscience (intuitive) aspects
  of the planning.

Eric Bernes transactional analysis
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