Magnetic Fluid Control for Optimizing the Energy - HS-OWL

Transcription

Magnetic Fluid Control for Optimizing the
Energy Efficiency for MRF-Actuators
(Magnetische Fluidsteuerung zur Optimierung der Energieeffizienz von MRF-Aktoren)
Dirk Güth, Jürgen Maas
Workshop der Nachwuchswissenschaftler im Rahmen der
Fachausschusssitzung „Unkonventionelle Aktorik”
(23. Oktober 2014)
Prof. Dr.-Ing. Jürgen Maas
Ostwestfalen-Lippe University of Applied Sciences
Control Engineering and Mechatronic Systems
Liebigstraße 87, Lemgo, Germany
[email protected], www.motion-ctrl.de
Outline

Introduction and motivation

Introductions and methodology of MR-fluid control

Concept for MRF-Clutch System with fluid control

Conclusion
(C) Control Engineering and Mechatronic Systems - Prof. Dr.-Ing. Jürgen Maas, Dirk Güth
Magnetic Fluid Control for Optimizing the Energy Efficiency for MRF-Actuators
2
1. Introduction and motivation
Magnetorheological fluids are suspensions of micrometer-sized magnetic
particles (e.g. carbonyl iron powder) in a carrier fluid, usually a type of oil.
Carbonyl iron powder particles on a human hair:
3
Carbonyl iron powder particles are suspended in a carrier oil by using additives for
reducing e.g. the sedimentation processes.
By applying a magnetic field, these particles form chains in the direction of the
magnetic flux, which change the yield stress up to 100 kPa of the MRF within
milliseconds depending on the magnetic flux density.
Operating mode for
B=0
brakes and clutches
F
MRF
B
shear mode
B≠0
rotational actuators
4
Shear gap design of MRF actuators based on the shear mode
radial shear gap:
axial shear gap:
particle
concentration
due to
centrifugal forces
r

r

Axial shear gaps offer:
• Advantages considering particle centrifugation at high rotational speeds due to an
inherent mixing effect (Taylor vortex flow) and an
• optimized torque generation due to the outside placed shear gap.
Güth, D.; Wiehe, A.; Maas, J.: Modeling approach for the particle behavior in MR Fluids between moving surfaces. 12th International
Conference on Electrorheological (ER) Fluids and Magnetorheological (MR) Suspensions, World Scientific, 2010.
5
Brakes and clutches based on MRF offer an enormous potential for
high energy application with high rotational speeds:


Advanced dissipation of energy in MRF brakes and clutches:
•
the scalable volume based energy dissipation in MRF brakes and clutches
•
the advanced compensation of thermal load peaks due to a braking fluid volume
•
the better dissipation of energy due to an advanced heat conductance
Challenge opposing a commercial use:
•
high rotational speeds  can be solved by an adequate design of shear gaps
•
viscous torque at high rotational speeds in idle mode

disadvantageous from an energy point of view of an application e.g. HEV

needless reduction of lifetime of the MRF
6
MRF-Brake with axial shear gap for high rotational speeds up to 6.000 min-1
electromagnet
housing
shear gap

bearing
rotor
shaft
B
magnetic circuit
seal
Dimensions of shear gap:
mean radius r = 41mm, height h = 3mm, length l = 40mm, volume VMRF = 32ml.
Güth, D.; Wiebe, A.; Maas, J.: Design of Shear Gaps for High-Speed and High-Load MRF Brakes and Clutches. 13th International Conference
on Electrorheological (ER) Fluids and Magnetorheological (MR) Suspensions, Journal of Physics: Conference Series, 2013, 412, 012046.
7
MRF-Brake with an axial shear gap for high rotational speeds
Measurements showing control characteristic lines for different rotational speeds at 𝜗𝑀𝑅𝐹 = 50°𝐶
Discussion:
30
n=500 min-1
25
n=2000 min-1
•
MRF brakes for applications
with high rotational speeds
can be realized
•
reproducible braking torque
even at high rotational
speeds
•
high viscous torque at high
rotational speed n (without
excitation, (I = 0A)
•
temperature depending
torque behavior needs to be
considered
n=3000 min-1
torque T in Nm
n=5000 min-1
20
n=6000 min-1
15
10
5
0
0
1
2
3
current I in A
4
5
Necessary conclusion:
• approach for reducing the viscous idle torque of MRF brakes and clutches
Güth, D.; Erbis, V.; Schamoni, M.; Maas, J.: Design and characteristics of MRF-based actuators for torque transmission under influence of high
shear rates up to 34,000 1/s. SPIE Smart Structures/NDE, Volume 9057, 90572P, 2014.
8
2. Simple concepts of MR-fluid control induced by force fields
• Shear gap volume are not completely filled with MRF for enabling a movement of the fluid.
• Use of different force effects like gravitational (orientation), centrifugal (rotation) and magnetic
Engaged
modes
forces for moving the MRF to achieve an engaged or disengaged mode.

Disengaged
modes

use of gravitational force for
disengagement and magnetic
forces for engagement
•
•
use of centrifugal force for
disengagement and magnetic
forces for engagement
US patent application, US 7,306,083, Magnetorheological fluid device, GM Global Technology Operations, 2005)
Patent application, “Magnetic Fluid Control”, 10 2011 119 919.9, Ostwestfalen-Lippe University of Applied Sciences, Germany, 2011.
9
2. Basic design concept of MR-fluid control
•
Advanced concept for complete disengagement during rotation and standstill.
•
Integration of a permanent magnet for achieving states like a current less braking torque.
•
Half section of the magnetically induced fluid control approach with a partially filled gap.
flange
electromagnet
housing
active
shearing gap
seal
inactive
shearing gap
magnetic circuit
permanent
magnet
shaft
ω
• MRF movement between an active and inactive shear gap.
• Energy input and idle losses can be reduced or at best completely avoided.
Güth, D.; Maas, J.: MRF actuators with reduced no-load losses. SPIE Smart Structures/NDE, Vol. 8341, S. 834121, 2012.
10
2. Basic design concept of MR-fluid control
•
Motion of the MRF is induced by a controlled leading of the magnetic flux resulting in
magnetic force acting on the MRF.
•
MRF can be switched between an active and inactive volume of the shear gap.
b)
braking/coupling
transition between
braking/coupling and
idle mode
idle mode
Güth, D.; Schamoni, M.; Maas, J.: Magnetic fluid control for viscous loss reduction of high-speed MRF brakes and clutches with welldefined fail-safe behavior. Smart Materials and Structures, Vol. 22, 094010, 2013.
11
2. Design methodology for MR-fluid control
•(Fig. 2/5)
•(Fig. 4)
•disengaged
 - current direction is moving into the page
 - current direction is moving up out of the page
i - inside EM
o - outside EM
•disengaged
•disengaged
torque transmission region
polarity of the PM
χr = 0
inactive region
electromagnet (EM)
χr >> 0
Güth, D.; Schamoni, M.; Maas, J.: Magnetic fluid control for viscous loss reduction of high-speed MRF brakes and clutches with welldefined fail-safe behavior. Smart Materials and Structures, Vol. 22, 094010, 2013.
12
3. Concept for MRF-clutch system with fluid control
Development of a new clutch systems for energy-efficient use:
•
Proof-of-Concept demonstrator as a clutch based on the fluid control for high rotational
speeds using magnetic forces of a permanent- and electro-magnet.
•
Integration of the fluid control in a sophisticated clutch design avoiding disadvantageous
slip rings for power supply.
1 Basic Concept:
driven shaft/inner rotor
stator/housing
electromagnet
active shearing gap
Performance Specification:
• Two permanent magnets are used
for a fail safe torque transmission
 No electrical control power for
torque transmission
permanent magnet
inactive shearing gap
2
•
•
• The electromagnet is used for the
idle mode
permanent magnet
 The idle losses can be
drive shaft/outer rotor
completely avoided
International patent application, PCT/DE2010/000230, WO2010/099788A1, „Apparatus for transmitting torque“ (Europe/USA/China), 2009.
Patent application, “Magnetic Fluid Control”, 10 2011 119 919.9, Ostwestfalen-Lippe University of Applied Sciences, Germany, 2011.
13
3. Concept for MRF-clutch system with fluid control
Development of a new clutch systems for energy-efficient use:
•
Proof-of-Concept demonstrator as a clutch based on the fluid control for high rotational
speeds using magnetic forces of a permanent- and electro-magnet.
Basic concept:
Engaged
modes
1
Magnification shown in
the simulation results
B
B
Engaged mode
Disengaged mode
2
14
3. Modeling of the magnetic field and the fluid movement
•
using an approach adapted from the theoretical model of ferrohydrodynamics
•
investigation of magnetic fields and their interaction with a magnetic fluid by magnetic
dipoles (fluid treated as a continuum with magnetic properties)
•
dipoles are accelerated in the magnetic field by Kelvin forces fK
f K   0  M   H   0  J TH  M
•
theory for the model based on Maxwells equations for the magnetic field and NavierStokes equations for the fluid flow
•
magnetic volume force from a calculated magnetic field coupled with a fluid-flow
problem
 v

 v   v   p    v    (g   2  r )   0  J TH  M
 t

 
Navier-Stokes equations
•
Kelvin force
two fluid domains (MRF and air) need to be considered due to the only partly filled
shear gaps
•
the interface between MRF and air is modeled by the level set method
15
3. Simulation of MRF-clutch system with fluid control
Simulation of fluid flow induced by magnetic fields for a clutch system
•
Results showing the transition from coupling to idle mode in standstill
(rotational speed n = 0 min-1).
t=0ms
t=10ms
volume fraction of MRF
100%
t=95ms
50%
1.6T
1.4T
1.2T
1.0T
0.8T
0.6T
0.4T
0.2T
0T
flux density
Magnetic
0%
16
3. Realization of MRF-Clutch System with Fluid Control
Concept finalized for realization with two magnetic cascades for increasing the maximum coupling torque.
1
sectional model
3D sectional
driven shaft
stator/housing
model of realized
clutch system
permanent magnet
winding
shear gap
drive shaft
driven shaft
permanent magnet
Design figures
shear gap radius:
2
MRF
magnification
of shear gap
63 mm
main length:
71,5 mm
outer diameter
140 mm
drive shaft
17
3. Measurements of MRF-clutch system with fluid control
•
Measurement of the steady state characteristic of torque behavior.
•
Measurement of the transient behavior for the transition from engaged in disengaged mode.
steady state characteristic
8
transient behavior
7
n=2000min-1
n=1000min
6
-1
n=500min-1
n=250min-1
5
8
n=500min-1
6
4
2
0
-50
n=100min-1
-40
-30
-20
-10
0
10
20
30
40
50
4
2
3
current I in A
torque T in Nm
torque T in Nm
n=3000min-1
2
1
0
-5
-4
-3
-2
current i in A
-1
0
desired current
measured current
0
-2
-4
-6
-50
-40
-30
-20
-10
0
10
time t in ms
20
30
40
50
Discussion:
•
High torque capability and idle mode with complete drag torque free operation.
•
Fast response times by switching from the engaged in disengaged mode within 15ms.
18
Integration in the power train of hybrid electrical cars (HEV):
•
A fast response time, an excellent controllability and no idle losses of the presented clutch systems
can provide significant benefits in terms of safety and efficiency for application in HEV.
•
Investigations utilizing a HIL test system, shows a good performance for application as switching
elements in power trains of HEV, e.g. as disengagement clutch in axle-split-hybrids.
Acceleration
E
MRF clutch
axle / street
electrical drive)
2000
0
0
5
transmitted torque
T in Nm
10
15
Disengagement
20
25
30
Engagement
0
-5
-10
0
(combustion engine )
electrical drive)
5
HIL test rig
(combustion engine and
driven shaft
drive shaft
current I in A
electrical
drive
rotational speed
in min-1
P
4000
Deceleration
Acceleration
(combustion engine and
5
10
5
10
15
20
25
30
20
25
30
10
5
0
-5
0
15
time t in s
19
Presenting the demonstrator on an “Island of Excellence” at FISITA 2012 in Bejing:
•
Using the great opportunity of
presenting the work on MRFclutches and brakes
Realized
Demonstrator
Güth, D.; Schamoni, M.; Cording, D.; Maas, J.: New technology for a high dynamical MRF-clutch for safe and energy-efficient
use in powertrains. Student Journal of FISITA, FISITA 2012 World Automotive Congress, Peking, 2013.
Starting new research work on MRF-clutches for application in transmissions:
•
For application in transmission for HEV, the torqueto-volume density needs to be increased.
•
Initiation of a new research project “PHEVplus”
beginning 2014 (partner GKN Driveline International,
financially funded by BMWi.
20
5. Conclusion
• Necessity of reducing the viscous losses of MRF actuators was shown by
measurements of an actuator with maximum rotational speeds.
• Idea of moving MRF within the shear gap for reducing the viscous drag losses in
the disengaged mode was introduced.
• Approach for a novel actuator design was presented.
• The functionality of the basic concepts is proven by measurement with a first
design.
• Development, modeling and simulation of an enhanced clutch design were shown
and a realized proof-of-concept clutch actuator was introduced.
• Measurements with the proof-of-concept clutch actuator were performed that show
the feasibility and the high potential of MRF clutches without idle losses e.g. for the
use in drive trains of vehicles.
• Improved concepts with higher torque exploitation are introduced.
• Considering the application in hybrid electrical cars (e.g. axle-split-parallelhybrids), a fast response time, an excellent controllability and no idle losses of the
presented clutch systems provide significant benefits in terms of safety and efficiency.
21
Thanks for your attention!
Dirk Güth M.Sc
[email protected]
Phone: +49 (0)5261 702-489
Prof. Dr. Jürgen Maas
Ostwestfalen-Lippe University of Applied Sciences
Department of Electrical Engineering and Computer Science
Control Engineering and Mechatronic Systems
[email protected]
Phone: +49 (0)5261 702-192
Research project PHEVplus, funded by the Federal
Ministry for Economic Affairs and Energy (BMWi) of
Germany under grant number 01MY13004B.

Magnetic Fluid Control for Optimizing the Energy - HS-OWL

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