Georgia Institute of Technology | Marquette University | Milwaukee School of Engineering | North Carolina A&T State University | Purdue University | University of California, Merced | University of Illinois, Urbana-Champaign | University of

Minnesota | Vanderbilt University

Fluid Power Innovation & Research Conference

Minneapolis, MN | October 10 - 12, 2016

STUDY OF AN ARTICULATED BOOM LIFT BY CO-SIMULATION OF BODIES’ FLEXIBILITY, VEHICLE DYNAMICS AND HYDRAULIC ACTUATION

Céline Cabana, Technical Account ManagerFD-GROUPS America, Inc.

www.fd-groups-america.com

Study by A. CHAIGNE, Haulotte GroupAnd G. JAUSSAUD, FLUIDESIGN Group

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Introduction

• Imagine.Lab Amesim study performed on hydraulic systems

• Observed gap between virtual model and actual machine

• Need for Co-Simulation in order to create a more reliable model

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Study performed in cooperation

withHaulotte Group is one of the

world leader in lifting technology. They design and manufacture a large range of products from aerial work platforms to articulated boom lifts.

FLUIDESIGN Group offers multi-domain 1D & 3D simulation services. We also designs and manufactures custom hydraulic components in small and medium series.

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NEW DESIGN -New Kinematics

Substantial risks:

Longer and higher-reaching boom

Backward stability of the machine

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Modeling StrategiesHydraulic model– Imagine.Lab Amesim

Objectives:• Confirm sizing of hydraulic components• Validate component choice• Verify hydraulic and mechanical stability

Content:• Kinematics• Hydraulic schematics• Hydraulic components• Controls• Contact wheels/ground

Mechanical model – Virtual.Lab Motion

Objectives:• Analyze kinematics• Confirm dynamic stability• Define movement control

• Calculate stresses in the connections

Content:• Kinematics • Rigid and deformable bodies• Fit in the connections• Ground contact

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Model Imagine.Lab Amesim

• Model « High Part »

– Unalterable Solids: (mass, inertia, CoG, Kinematic connections)

– Connections with contact forces

– Actuator 3D– Hydraulic actuation– Hydraulic circuit (feed)– Super components

CAD

Import from STEP files

Kinematics

3D Joints

Actuation

3D jacks, Hydraulic jacks

Solving

Robust, accurate

Post-processing

1D / 3D

Power

hydraulic systemand components

• Complete Model

– Parts

– Chassis

– Contact wheel/ground

– Behaviors on the road

– Oscillating axle

– Hydraulic transmission circuit

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Model Imagine.Lab Amesim -OUTPUTS

• Model « High Part »

Verification of the kinematic and dynamic of Boom Lift

- Compensation- Speed and

accelerations in the bucket

=> Validation of the hydraulic control

CAD

Import from STEP files

Kinematics

3D Joints

Actuation

3D jacks, Hydraulic jacks

Solving

Robust, accurate

Post-processing

1D / 3D

Power

hydraulic systemand components

• Complete Model

=> Verification of the vehicle stability (without tipping)

=> Validation of the transmission

=> Validation of the compensation by the oscillating axle

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Model Virtual.Lab Motion

Simple model:

– Simplified representation

– Perfect kinematics links

– Mass & Inertia from CAO

– Dynamic results

CAD

Create in VLOr import

Kinematics

JointsConstraints

Initial conditions

Dynamics

Forces (Gravity,Stiffness, Damping,

loads, ..)

Flexiblebodies

Craig-Bampton or test deformation

modes

Solving

Fast, Robust,Accurate

Post-processing

2D / 3D

Advanced model:

– Parts distortion

– Mode reduction (Craig Bampton)

– Recovery of the Ansys data

– Ansys solver control

– Contact wheels/ground

– Fit in connections

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Co-Simulation• Linkage between mechanical and hydraulic models• Validation that models in each of the tool are linked

Control Input

Control Output

Vir

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l.La

b M

oti

on

AM

ES

im

Control Nodes

Model AMESim mechanical + hydraulic : long calculation time due to the frequency difference between physicsModel paired AMESim+VLAB Motion : reduction in calculation time

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Co-Simulation

Virtual.Lab Motion• Kinematics• Angle sensor• Link wheels/ground• Flexibility parts

Profile % opening/angle sensor

Spool stroke PVG

Counterbalance Valve

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Boom Lifting ProfileCriteria:

– Normal: Vertical speed close to 0.4m/s

– Felt: Bucket speed felt to be as constant aspossible

– Safety: Low Speed in the final approach

Mechanical curve

Hydraulic curve

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PumpingDescription:

Risk not anticipated & not seen in the Imagine.Lab Amesim model

– At the end of the lifting, when the pistontouches the cap end, pressure is at itsmaximum

– The balancing valve « retains » this pressure

– In the descent movement, this pressure isreleased and destabilizes the system

– The phenomena is magnified during thedescent

Evaluation of different solutions:

– Increasing cylinder

– Modification ratio counterbalance valves

– Throttle of return

– Descent controlled in pressure

– Depressurization

Two possible solutions retained

Spools control before the release of the prototype

First trials consistent with model

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Conclusions• Results

– Enhance system safety– Time saving in fine-tuning– Time reduction in development– Guarantee in the reliability of the system– Help to make decisions– Powerful engine for on-going innovation

• Perspectives

– Systematize modeling• Components library• Integration to the development process

– Integration of the controllers (SiL / HiL) in the co-simulation process

=> Creation of a virtual prototype