individual electro-hydraulic drives for off-road vehicles ...€¦ · gear pump interface to tandam...
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##1
Individual Electro-Hydraulic Drives
for Off-Road Vehicles
(a DOE supported project)
Maha Fluid Power Research Center
Purdue University, West Lafayette, IN (USA)
https://engineering.purdue.edu/Maha/
Andrea Vacca (PI)
Dr. Sudhoff (co-PI) Uwe Neumann, Enrique Busquets Gary Kassen, Roman Plaszewski
##2
Classical centralized
architecture
Hydraulic Individualization
Electrification
Basic idea
##3
Electric – Hydraulic Hybrid
architecture
Main features
✓ Self contained individual drives
✓ No fluid throttling
✓ Energy recuperation
✓ Reduced ICE size
✓ Enables smart actuators, operating
as modern “plug & play” elements
✓ Zero emission modes
DOE Objective: Lower power
consumption of the fluid power
system up to 70%
Basic idea
##4
P
Objective 1 (O1). 4-quadrant EH hydraulic unit
Objective 2 (O2). Individualized EH system
Objective 3 (O3). Technology demonstration
Key components
##5
reference vehicle
##6
Off-road construction vehicle: skid-steer loader Case TV 380
boombucket
• Two functions (boom, bucket) considered for the technology demonstration
• Machine instrumented for baseline measurements of hydraulic power consumption
• Tests representative of typical machine duty cycle
Machine Main Specification
Engine TypeDiesel, Turbo – Direct
Injection,4 cylinders
Max power 90 hp [67 kW]
Fuel Capacity 25.5 gal [96.5 L]
Max Standard flow 24.2 gpm [91.5 L/min]
Machine Weight 10,207 lb [4630 Kg]
Engine speed 1150-2500 rpm
Reference vehicle
##7
Pump 1
Self Level
MR
Line 2
Line 3
Line 4
P5
P1
P2
P3
P4
Unit 2
Unit 1
Unit 3
Unit 4
metering
D1
Lift Cylinders Tip Cylinders
Hydraulic Couplers
Auxiliary Quick
Disconnections
Secondary Auxiliary
Quick Disconnecions
Gear Pump interface
to Tandam Pump Line 1Hyd Oil Filter
wl 50psi Bypass
Oil Cooler
wl 75psi Bypass
PR1 PR2 PR3
D2
Bucket
Boom
Tip Cylinder
Lift Cylinder
7
Cylinders
Case TV380
Instrumentation:
• Pressure sensors
• Position sensors
• Flow metering
Pump
Open Center Valves
Reference vehicle
##8
Raise Lower Raise Lower
high load – low speed low load – high speed
𝐹𝑝1𝑝2
Boom test
##9
High pressure
Low pressure
Boom control ሶ𝑥 ሶ𝑥
Raise Lower
Open Center System
##10
Area function plot (lowering)
Ω𝐵𝑇
Ω𝑃𝐴
Ω𝑃𝑇
𝐹
ሶ𝑥
𝐹
ሶ𝑥
Ω𝑃𝐵
Ω𝐴𝑇Ω𝑃𝑇
Raising phase (resistive) Lowering phase (overrunning)
Open Center System
##11
Equivalent Load
Pump PowerFull command, 1000 pounds load
Essential for sizing the EHA
Power Demands
##12Power Demands
##13
proposed solution
##14
VALVES
ECU
VALVES
ECU
Boom control (EHA)
main control
unit
Operator interface
Energy StorageBattery
EngineGeneratorICE
External Grid
Bus
EHA Power Electronics
Bucket control (EHA)
DC Link Distribution
EHA Power Electronics
• EHA units are powered by a vehicle DC
power distribution network
• Power electronics convert DC voltage into
three-phase AC currents to regulate electric
machine torque, and thus pump output
Proposed Architecture
##15
MOT
Proposed Architecture
##16
MOT
MOT
MOT
MOT
Δ𝑝
ሶ𝑥
𝐹 > 0𝐹 < 0
𝐹 = 𝑝1𝐴 − 𝑝2𝑎
𝑄𝑎𝑐𝑐 = 𝑄𝑎 𝜑 − 1
𝑄𝐴
𝑄𝑎𝑐𝑐
𝑄𝑎
𝑄𝐴
𝑄𝐴
𝑄𝑎𝑄𝐴
ሶ𝑥𝐹
𝑄𝑎𝑐𝑐 = 𝑄𝑎 𝜑 − 1
𝑄𝐴
𝑄𝑎𝑐𝑐
𝑄𝑎
𝑄𝑎𝑄𝐴
ሶ𝑥𝐹
𝑄𝐴
𝑄𝐴𝑄𝑎𝑐𝑐 = 𝑄𝑎 𝜑 − 1
𝑄𝐴𝑄𝑎𝑐𝑐
𝑄𝑎
𝑄𝑎𝑄𝐴
ሶ𝑥𝐹
𝑄𝑎
𝑄𝑎
𝑄𝑎𝑐𝑐 = 𝑄𝑎 𝜑 − 1
𝑄𝐴𝑄𝑎𝑐𝑐
𝑄𝑎
𝑄𝑎𝑄𝐴
ሶ𝑥 𝐹
𝑄𝑎
𝑄𝑎
High pressure
Low pressure
𝐴 > 𝑎
Working Modes
##17
Δ𝑝
ሶ𝑥
𝐹 > 0𝐹 < 0
Working Modes
##18
Model of the hydraulic system
Model of the mechanism
Bucket
Boom
Tip Cylinder
Lift Cylinder
Simulation
##19Simulation
##20
Load data
from tests
Displacement tracking
𝜂𝑣𝑜𝑙 𝜂ℎ𝑚
Simulation
##21Simulation
##22
Raise LowerFor the proposed system:
• results based on simulation
• regenerates energy when
lowering
Results: boom cycle
##23
Remarks
✓ Closed vs open
circuit architecture
✓ Independence on load
𝜂 =𝐸𝑟𝑒𝑓
𝐸𝐸𝐻𝐴× 100%
Results: boom cycle
##24
Raise boom Lower boomBucket
downBuc
up
Results: boom/bucket cycle
##25
EH unit
##26
Fluid-Dynamic Module
-Analysis of Main Flow
-Effect of Porting grooves
-Aeration and Cavitation
Lateral Gap Module
Fluid Structure and
Thermal Interaction
Loading Module
Evaluation of
Instantaneous Radial
Forces and Torque
Journal Bearing
Module
Fluid Structure
Interaction
Micro-Motion Module
Evaluation of Gears’
Micro-Motion
Noise FEM/BEM Module
-Fluid-Borne Noise
-Structure-Borne Noise
-Air-Borne Noise
CAD Drawings
Geometrical Module
-Flexible geometry from CAD
-Asymmetric teeth
-Cycloidal-involute Profile
-Helical Gears
HYGESim (HYdraulic GEar machines Simulator)
Model Integration
##27
Set of optimal design
solutions
Electric drive
performance
Mechanical output
Operating Conditions
Magnetic
Material Characterization
Winding Configuration
Vehicle power
requirements;
EHA requirements;
manufacturability constraints; …
Geometry
Candidate Create
feasible
geometry
Hydraulic
s
Mass,
volume, ...
Electric
Analysis
Magnetic
Analysis
Control
Leakage and
magnetizing
inductances,
Ohmic resistance,
proximity effect,…
Select current
commands,
winding and
semiconductor
losses, …
Core
losses,
torque, …
Electric Drive Optimization
Model Integration
##28
Objective functions
1. Minimize Cycle Power
2. Minimize EH Volume
3. Minimize Flow Ripple
4. Minimize Torque Ripple
Optimization
Design GoalsParametrize
Problem
Generate
Design
Calculate
Performance
Adjust
Parameters
Problem Definition
Optimize for Problem
𝑥𝑐𝑦𝑙
𝑡
𝑡𝑟𝑎𝑖𝑠𝑒 𝑡𝑙𝑜𝑤𝑒𝑟
2 3
##29
Nominal
Peak
𝜃1𝑋1
𝜃𝑃
𝑋3
HP
LP
𝜃3
𝜃𝑐
Optimization
##30Arrangement
##31Arrangement
##32Arrangement
##33
Conclusion
##34
O1. EH unit
• Design integration including alternative cooling solutions
• Performance evaluation internal gear vs external gear design
• Identification of tolerances and fabrication process
• EH Testing and verification of performance
O2. EH module
• Space limitation on the demo vehicle for applications
• Simultaneous actuation of multiple actuators
• Prototype implementation and testing
O3. Technology Demonstration
• Supervisory controller for energy management
• Zero emission mode of operation
• Integration of energy generator and power electronics
• Performance measurements
Remaining challenges
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