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Hybrid MachineToolySimulation
이병흠 과장
㈜ 캐즈테크
Contents1. General Introduction to Machine Tool Simulation
2. MFBD Modeling of Machine Tool Parts
3. General Machine Tool Components
4. Cutting Force Implementation - Exampleg p p
5. Analysis Example
2
❶ Improved insight into the system mechanics / control Simulate displacement, velocity, acceleration of each body
Calculate reaction forces torque stresses everywhere in the struct
General Introduction to Machine Tool Simulation
Calculate reaction forces, torque, stresses everywhere in the structure
“Slow Motion” of system functionality
Parameter studies and optimization – “What if” studies
❷ Cost/Risk reduction through “Preventive Simulation” Traditionally the development of machine tools uses the try and error method
based on prototyping and engineering experience
General Introduction to Machine Tool Simulation
p yp g g g p
With the use of simulation the manufacturer has the possibility to make changes on his virtual prototype very fast and without the cost generating step of physical prototyping
Due to this new concept of product development the Machine Tool manufacture reduces the time to market and gets key benefits compared to its competitors
[SIEDL]
3
❸ Trouble shooting Understanding reasons of system performance failures
Upfront testing of different solution concepts
General Introduction to Machine Tool Simulation
Upfront testing of different solution concepts
Parameter studies / sensitivity studies
Example Chatter Vibrations -influenced by the dynamic machine tool behavior
❹ Special Requirements for Simulation Simulation requirements are very complex in nature
Physical description are often extremely difficult; FEA vs MBD
General Introduction to Machine Tool Simulation
Physical description are often extremely difficult; FEA vs. MBD
High precision of the simulation results necessary
In most cases a simulation department does not exist
The catalyst effect
Initial additional efforts have to be accepted
Uncertainties and risk management
Effort/Benefit without VP
Project Duration
Effo
rts
4
❺ Value generating by simulationOpportunities for machine tool manufactur
ers:
General Introduction to Machine Tool Simulation
Testing of new and innovative concepts with reduced risk of system level failure
High optimization potential due to parameter studies
Identification of machine tool structural weak points early in the design phase
Study interaction between machine structure and motion control engineering
[BÜRGEL]
Improve machine precision and cutting power
Product vision: Virtual commissioning of a machine tool
General Introduction to Machine Tool Simulation
Historical Machine Tool Simulation (FEM & MKS)
5
FEM only allows structural analysis o
Historical Machine Tool Simulation - Based on Finite Element Analysis (FEM)
General Introduction to Machine Tool Simulation
FEM only allows structural analysis of machine tool behavior at discrete locations
But machine tool behavior is much more than only structural behavior therefor critical quality aspects are neglected:
Dynamic influences Dynamic influences
Non linear behavior
Controller feedback
[ÖRTLI]
Historical Machine Tool Simulation - Based on Multi Body Simulation (MBS)
General Introduction to Machine Tool Simulation
Historicaly the multi body simulation of machine tool only builds up the rigid body movement forced by forces and constraints.
This neglects the structural deformations out of the eigenvalue movements charged of external forces
[WECK]
6
StaticsDynamicsSt t l A l i4
Historical Machine Tool Simulation - Changes
General Introduction to Machine Tool Simulation
Multi Rigid Body DynamicsSystem Level Design
Structural AnalysisLocal Stress Analysis,Linear FEAPart Level Design70
-84
85 -
991
Flexible Body DynamicsLinear, small deformationModal synthesis technique,Co-Simulation (Interface)
Structural DynamicsLarge Deformation Non-Linear FEA
System & Local Level SimulationIntegrated Multi Physics
System & Local Level SimulationIntegrated Multi Physics
MFBD(Multi-Flexible-Body Dynamics)
00 -
1 g ySimulation (MBD, Linear & Nonlinear FEA, CFD, Hydraulics, Control, Electro & circuit, Durability, etc.,)
Simulation (MBD, Linear & Nonlinear FEA, CFD, Hydraulics, Control, Electro & circuit, Durability, etc.,)
General Introduction to Machine Tool Simulation
Advantages of Multi Body Simulation in Machine Tool Development
7
General Introduction
Simulation task: Complete system simulation of mechatronic systems
RecurDyn Solution:
Advantages of integrated Multi Body Simulation in Machine Tool Development
Agenda
General Introduction
Software Setup
MFBD Modeling
General Components I
Integrated Graphical User Interface
RecurDyn FEMBD:
M d l d ti (RFLEX)
Integrated simulation environment for Multi-Body Dynamics, Finite - Element Analysis and Controls
Integrated Multi- DisciplineDynamics Solver (IMD)
Components I(Basic machine element)
Cutting Force
Driving Systems
Analysis IResponse Simulation
Actuation IExpression
Actuation IICoLink
Hybrid Modeling
Post Processing / Val Modal reduction (RFLEX)
Non - linear FEA (FFLEX)
RecurDyn Controls integration
Co - Simulation
Full integration with RD/Colink
Post Processing / Value Generating
Future Developments of FBG Machine Tool
Advantages of integrated Multi Body Simulation in Machine Tool Development
General Introduction to Machine Tool Simulation
FEM iMBD
Machine Tool Components:
Computerized Numerical Control
Programmable Logic Controller
Electrical Components
Mechanical Components
[SIDL]
FEM iMBDMBS
Process TechnologyMFBD
8
Applying flexibility to Multi Body Systems
Vision: Enhanced representation of machine behavior at the system level by consideration of component elasticity
General Introduction to Machine Tool Simulation
consideration of component elasticity
Increase the simulation accuracy by recording component deformations, mechanical resonances, …
Integrated stress analysis based on dynamic loads
Consideration of static and dynamic component deformations. Example: rocker arm
Abb. Positionsfehler Abb. GeschwindigkeitsfehlerAbb. Beschleunigungsfehler
Collection of machine resonances and natural oscillations due to periodic stimulation
Applying flexibility to Multi Body Systems
General Introduction to Machine Tool Simulation
f = 40 Hz
n140
160
180
N
200
0,8 0,9 1 1,2Zeit
Cuttin
g F
orc
e
1,1
stimulation
9
Mechatronical Simulation
Apart from structural effects the transient
General Introduction to Machine Tool Simulation
behavior of machine tool is highly affected by the numerical control systems.
Fore example: the Kv - Factor (speed/stroke gain)Indicates the speed in which a particular position error is set to zero. The higher the Kv the faster the system but this also makes the system ustable…
[BÜRGEL]
Mechatronical Simulation
… the simulation of the control system shows these effects easily. But only in
General Introduction to Machine Tool Simulation
… the simulation of the control system shows these effects easily. But only in combination with the structural/mechanical model the developer is able to see how this is affecting the machine tool behavior
10
Hybrid machine tool modelingThe efficiency of machine tools is highly affected by several aspects. Common simulations (MBS – FEM – Control) have to be combined to validate the transient
General Introduction to Machine Tool Simulation
( )behavior of machine tools correctly. Due to the cost in time, money and accuracy this combination requires greater focus on the system level each machine tool component has to be simulated in.
discretization
Workshop@:
optimization
General Introduction to Machine Tool Simulation
Value generating by Machine Tool simulation - Examples
11
❶ Circularity Tests (ISO 230 T2) Standard acceptance certificate for general machine tools
General Introduction to Machine Tool Simulation
The NC-Control pretends an ideal circular orbit for the die holder
Circular movement by controller or spline
Variations of the pretended and measured circle are related to typical machinery failure
[WECK]
❶ Circularity tests (ISO 230 T2) (2) RecurDyn validation
General Introduction to Machine Tool Simulation
12
❷ Frequency response / impact analysis Through a targeted impact the structure will be stimulated to os
cillate in a broadband spectrum
General Introduction to Machine Tool Simulation
cillate in a broadband spectrum
Goal is to rebuild the characteristic function for the transfer behavior
RecurDyn validation
❸ Chatter vibration Effected by the interaction of dynamic machine- and the dynamic cutting-behavior
St bilit l l t d b N i t C it i
General Introduction to Machine Tool Simulation
Stability calculated by Nyquist Criteria
With
13
❸ Chatter vibration (2)
General Introduction to Machine Tool Simulation
[WLZ]
Challenges Solution
Machine tool simulation challenges
General Introduction to Machine Tool Simulation
CAE Technology :System level simulations of MT require multi-discipline analysis capabilities
RD/IMD Technologyprovides integrated MBD, FEA and Controls functionality in one single environment
Machine Tool Know – How :Compared to MT manufacturers, software companies typically don’t have
the same level of application know-how measurement equipments for model
validation
MT companies adapted software implementation :The above mentioned special situation of
Technology Consortium :between:
Technical University of Munich: Technology provider
FRAMAG (Austria): MT manufacturer FunctionBay GmbH: Software
implementation
MT specific toolbox:Predefined component library, analysis and post-processing capabilitiesThe above mentioned special situation of
MT companies require customization of standard software packages
and post processing capabilities
Technology – Partners:
14
General Multi Body Simulation(StartUp)
MFBD Modeling
MFBD Modeling of Machine Tool Parts
Goal: Get a short Introduction to the several body types in RecurDyn
When should I use which body formulation in machine toolWhen should I use which body formulation in machine tool simulation
Get sensitive for body limitations
Rigid Bodies
Body of infinite extent Inertia are determined by
MFBD Modeling
2nd order DE
0sin qgq
qu Reduce Order Equations
1st order explicit DE
qg
u
u
q
sin
y
1st order implicit DE
0sin
),,(
qgu
uqtyyF
1st order BDF
Body of infinite extent. Inertia are determined by geometry or user
❶ Geometry construction via:Primitive objects and Boolean operationsImport from common CAD systems
(E.g.: STEP, PARASOLID, IGES, …)
❷ Degrees of freedom : #6DoF
1 order BDF
h
yy
t
y nn
1y
Explicit solver
nnn
nnn
qghuu
huqq
sin1
1
Implicit solver
0sin
0
11
11
nnn
nnn
qghuu
huqq
Newton Raphson iterationIterative solution
❸ Connections to any desired coordinate
❹ Contacts on the topology geometry
15
RFlex Bodies
FE-Modell of the body is condensed to the stiffness betwe
MFBD Modeling
FE-Modell of the body is condensed to the stiffness between so-called interface nodes by the use of the Craig-Bampton method
❶ Meshing via Preprocessor(E.g.: RD-Mesher; NX 7.5 )
❷ Modal Condensation via FEM-Solver(E.g.: RD-Mesher; Nastran)
❸❸ Degrease of Freedom: #6DoF a Interface-Node
❹ Contact formulation not available
FFlex Bodies
Non-linear FE-model of the body serves all degrees of freedom on every
MFBD Modeling
Non linear FE model of the body serves all degrees of freedom on every node
❶ Meshing via Preprocessor(E.g.: RD-Mesher; NX 7.5 )
❷ Degrees of Freedom: #6DoF each Node
❸ contacts trough so-called patch setsavailable on every node
❹ Calculation via:“Relative Nodal Displacement Method“(BAE, CHOI, CHO)
16
Lesson1: MFBD Modeling
Build up a simple fixed bar with a applied load
MFBD Modeling
Build up a simple fixed bar with a applied load
import a FFlex model
Import a RFlex model
Analyzing the difference
Exploring RecurDyn
RFlex Bodies are linear Modal Reduction is linear and only valid for small deformat
ions
MFBD Modeling
No large rotations of the flexible body concerning the deformations (But the flexible body can lead large rotations in the MBS)
Abb. Modale Reduktion Abb. Nicht – lineare Lösung mit RecurDyn/FFLEX
17
General Multi Body Simulation(StartUp)
General Components I
Goal: Get a short Introduction of Constraints Forces and Expressions
When should I use which abstractionGet sensitive for solving times
Bearing and Clutch Simulation:
The simulation of rotational degrees of
General Components I
freedom could be set on different system level abstraction. Starts by fixing single DOFs to the flexible simulation of each bearing ball.The level of discretization had to be set on the values to be generated by the simulation
18
Bearing and Clutch Simulation:
Due to the fact that bearing and
General Components I
clutches are only components of machine tools the focus of the simulation has to be set on a low level discretization but with the maximum effects to see in the simulation
Lesson2: Modeling of General Components I
Editing a driving system with different
General Components I
Editing a driving system with different kinds of bearing models
Post processing the effects
Building up clutch models
Post processing the effects
Exploring RecurDyn
19
General Multi Body Simulation(StartUp)
Cutting Force Implementation
Goal: Showing two different ways of cutting force implementation in RecurDyn
Building up an MBS model of a cutting force
This theory is based on the division of the cutting force along the cutting edge by using the Thales circle This leads trough the shear stress along the cutting e
Cutting force Theory - Merchant
Cutting Force Implementation
y using the Thales circle. This leads trough the shear stress along the cutting edge and in this way trough the active force.
[MÜLLER]
Based on the geometrical set of the cutting force is calculated:
20
For cutting processes with geometrically determined bits the reacting force could be set as three different orthogonal force vectors
Cutting force Theory – Viktor&Kienzle
Cutting Force Implementation
ld be set as three different orthogonal force vectors
Viktor-Kienzle formulates a correlation of the chip geometry and the specific
cutting force g
[FISCHER]
As shown on real cutting processes the specific cutting force is just constrained by the chip height – the with is not effecting the specific cutting force in a releva
Cutting force Theorie – Viktor&Kienzle
Cutting Force Implementation
by the chip height the with is not effecting the specific cutting force in a relevant way
[FISCHER]
with this information the principal value of the cutting force is calculated (chip geometry A= 1mm x 1mm) and available on tables. Thou the reacting forces can be calculated as:
21
Cutting force Practicaly – Viktor&Kienzle To calculate the Victor-Kienzle cutti
ng force in a multi body system it is
Cutting Force Implementation
ng force in a multi body system it is necessary to assign the correct value of the chip area
However you need to setup the model with three reference Markers
To get the natural deflection of the clamping a dummy body is necessarp g y yy. This dummy body gets the feed of the tool and the avoiding position of the work part
The force formulation is set as three Expressions
Lesson3: Cutting force implementation (Victor-Kienzle)
Building up a 3 component force with
Cutting Force Implementation
Building up a 3 component force with
cutting force characteristics in a lathe
model
Exploring RecurDyn
22
Cutting force Evaluation
Evaluation Examples:
Cutting Force Implementation
Design of cutting profile
Creating stability charts
Evaluation of cutting process
Evaluation of cutting limits
RecurDyn & FBG.MachineTool Specific Simulation
Driving Systems
Goal: Showing the main machine tool driving systems
Showing abstraction levels that could be simulatedIntroduction to the FBG.MachineTool
23
Ball Screw Stiffness model
Driving Systems
Iey
x y z
Ic
Nut
Spheres
Iex
x y z Ix
Iy
Shaft
Ball Screw (2) Automatic load / torque “hand-over” from
one beam element to the next
Driving Systems
one beam element to the next
Implementation as user-written subroutine
RecurDyn force element: matrix force
24
Lesson4: Driving a MachineTool via Ball Screw Systems
Implementing flexible driving system
Driving Systems
Possible System level abstraction
Joint coupler (RecurDyn Professional Functionality) Not recommended – caused on value generation
Timoshenko Beam (RecurDyn FBG MachineTool) R
Implementing flexible driving system
Exploring RecurDyn
Timoshenko Beam (RecurDyn FBG.MachineTool) Recommended
Linear guides Automatic parabolic load distribution to nodes with
automatic stiffness correction
Driving Systems
automatic stiffness correction
RD/MT automatically creates matrix forces elements according to user specified parameters (guide stiffness, geometric dimensions, …)
bodyposm
bodyposm
∆x/2
∆xn-2 n-1 n+1
yI
xI
yn
xn
xB
n
nodepos
An-2
An-1 An An+1
An+2
n+2
∆x/2
∆xn-2 n-1 n+1
yI
xI
yn
xn
xB
n
nodepos
An-2
An-1 An An+1
An+2
n+2
25
Linear guides (2) Examples and validation
Driving Systems
Lesson5: Driving a Machine Tool via Linear Guides
Getting started with driving large displacements on flexible bodies
Driving Systems
Possible System level abstraction
Joint (RecurDyn Professional Functionality) Not recommended – caused on value generation
Contact Modeling (RecurDyn Professional Functionality) simulation of non-stiff guiding systems (E.g.: air bearing)
g g g p
Exploring RecurDyn
earing)
Timoshenko Beam (RecurDyn FBG.MachineTool) Driving large displacements on flexible systems, were the bending along the driving axis is dominant
FFlex (RecurDyn FBG.MachineTool) Get all detailed information from every node of the FFlex model
26
RecurDyn & FBG.MachineTool Specific
Simulation
Response Analysis
Goal: Showing a typical analyzing method in the Machine Tool simulation
Signal Handling Advantage of measurement comparison
Response Analysis Investigate the structural behavior of the machine tool by different vibrati
on excitation (Impact Hammer, Shaker etc.)
Response Analysis
on excitation (Impact Hammer, Shaker etc.)
27
Lesson6: Response Analyses with Impact Hammer
Generate Impact Force
Response Analysis
Generate Impact Force
Generate Impact Signal
Evaluate Signal
Evaluate Structural Machine Tool Behavior
Exploring RecurDyn
RecurDyn & FBG.MachineTool Specific Simulation
Actuation Simulation
Goal:Modeling an alternating circular motion for a circularity test
Run a circularity analysis with the FBG.MachineTool
28
Lesson7: Driving a Circularity Test via Expression
Generate driving motion
Actuation Simulation
Generate driving motion
Generate a FBG.MachineTool circularity test
Evaluate simulation
Exploring RecurDyn
RecurDyn & FBG.MachineTool Specific Simulation
Actuation Simulation
Goal: Getting Started With RecurDyn ColinkGenerate controller Communication
Design simple controllermodel
29
Mechatronic Simulation Controller and Structural Machine
Use integrated controller design for optimization of control design and pa
Actuation Simulation
Use integrated controller design for optimization of control design and parameters depending on structural behavior of machine tool
Include model of Electrical driving Engines to generate real feed torque
Lesson8: Driving a Circularity Test via CoLink
Generate interface (Plant In and Outputs)
Actuation Simulation
Generate interface (Plant In and Outputs)
Generate simple PID- Control
Generate controlled circularity motion
Evaluate simulation
Exploring RecurDyn
30
RecurDyn & FBG.MachineTool
Specific Simulation
Hybrid MachineTool Simulation
Goal: Building up a complete machine tool model in a row (practice the
last chapters)Driving first analysis
Lesson9: Combine Knowledge
Hybrid MachineTool Simulation
Build up a circularity test model in a row
The goal is to characterize the structural behavior of the ground and the middle structure
Exploring RecurDyn
31
RecurDyn & FBG.MachineTool Specific Simulation
PostProcessing
Goal: Post Process The Hybrid Model of the last chapter
Lesson10: PostProcessing
PostProcessing
Build up a circularity test model in a row
The goal is to characterize the structural behavior of the ground and the middle structure
Exploring RecurDyn
32
Future Developments of FBG MachineTool
Mechatronic Simulation optimization Providing standard control system library in RecurDyn CoLink as an “eas
y to change” library for the fast integration of different control systems int
Future MachineTool Developments
y to change library for the fast integration of different control systems into the multi body system
33
Real-Time Programmable Logic Controller (PLC) coupling Programmable Logic Controller (SERCOS III)
P iti t ll (S i L b)
Future MachineTool Developments
Position controller (ScicosLab)
Simulation (FunctionBay RecurDyn)