hybrid machinetool simulation · · 2012-04-244 value generating by simulation opportunities for...

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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

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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


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]

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❸ Trouble shooting Understanding reasons of system performance failures

Upfront testing of different solution concepts


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


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

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❺ Value generating by simulationOpportunities for machine tool manufactur

ers:


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


Historical Machine Tool Simulation (FEM & MKS)

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FEM only allows structural analysis o

Historical Machine Tool Simulation - Based on Finite Element Analysis (FEM)


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)


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]

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StaticsDynamicsSt t l A l i4

Historical Machine Tool Simulation - Changes


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.,)


Advantages of Multi Body Simulation in Machine Tool Development

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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


FEM iMBD

Machine Tool Components:

Computerized Numerical Control

Programmable Logic Controller

Electrical Components

Mechanical Components

[SIDL]

FEM iMBDMBS

Process TechnologyMFBD

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Applying flexibility to Multi Body Systems

Vision: Enhanced representation of machine behavior at the system level by consideration of component elasticity


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


f = 40 Hz

n140

160

180

N

200

0,8 0,9 1 1,2Zeit

Cuttin

g F

orc

e

1,1

stimulation

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Mechatronical Simulation

Apart from structural effects the transient


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


… 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

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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


( )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


Value generating by Machine Tool simulation - Examples

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❶ Circularity Tests (ISO 230 T2) Standard acceptance certificate for general machine tools


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


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❷ Frequency response / impact analysis Through a targeted impact the structure will be stimulated to os

cillate in a broadband spectrum


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


Stability calculated by Nyquist Criteria

With

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❸ Chatter vibration (2)


[WLZ]

Challenges Solution

Machine tool simulation challenges


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:

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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

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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)

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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

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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


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

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Bearing and Clutch Simulation:

Due to the fact that bearing and


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


Editing a driving system with different kinds of bearing models

Post processing the effects

Building up clutch models

Post processing the effects

Exploring RecurDyn

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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


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:

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For cutting processes with geometrically determined bits the reacting force could be set as three different orthogonal force vectors

Cutting force Theory – Viktor&Kienzle


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


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:

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Cutting force Practicaly – Viktor&Kienzle To calculate the Victor-Kienzle cutti

ng force in a multi body system it is


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


Building up a 3 component force with

cutting force characteristics in a lathe

model

Exploring RecurDyn

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Cutting force Evaluation

Evaluation Examples:


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

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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

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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

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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

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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.)

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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


Actuation Simulation

Goal:Modeling an alternating circular motion for a circularity test

Run a circularity analysis with the FBG.MachineTool

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Lesson7: Driving a Circularity Test via Expression

Generate driving motion


Generate driving motion

Generate a FBG.MachineTool circularity test

Evaluate simulation

Exploring RecurDyn



Goal: Getting Started With RecurDyn ColinkGenerate controller Communication

Design simple controllermodel

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Mechatronic Simulation Controller and Structural Machine

Use integrated controller design for optimization of control design and pa


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)


Generate interface (Plant In and Outputs)

Generate simple PID- Control

Generate controlled circularity motion

Evaluate simulation

Exploring RecurDyn

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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

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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

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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

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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)

hybrid machinetool simulation · · 2012-04-244 value generating by simulation opportunities for...

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