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Model Based Control for a Pressure Control Type CVT. Wansik Ryu, Juhyun Nam, Hyunsoo Kim, Sungkyunkwan University Yongjoon Lee, Hyundai Motor Company. Dynamic System Design & Control Lab. Sungkyunkwan University. Introduction. Flow Control Type. Pressure Control Type. - PowerPoint PPT Presentation
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Model Based Control for a Pressure Control Type CVT
Wansik Ryu, Juhyun Nam, Hyunsoo Kim, Sungkyunkwan University
Yongjoon Lee,Hyundai Motor Company
Dynamic System Design & Control Lab.Sungkyunkwan University
2
Introduction
Pressure Control TypeFlow Control Type
Pressure control is easier than the flow control in maintaining the desired CVT speed ratio.
Pressure control system has an advantage of preventing the belt from slippage in active manner.
3
Design a ratio controller for pressure control type CVT
Design a model based controller
Investigate model based controlled CVT shift performance
Purpose of Study
4
Pressure Control Type Ratio Control Valve
Solenoid presusre Feed back pressureSpring force
5
CVT System Dynamics
FrM
PBXXKPAPAP
PS
PSPSPSPSPSsolPS )( 0331
dt
dXAQ
dt
dPXAV ppp
pppP dt
di
di
dX
dt
dX pp
Force equilibrium of the spool motion
State equation of the primary pressure
CVT shift dynamics by Ide (1995)
Pi
PPidt
di
P
ppP
)(
)()( *
where
6
Pressure Characteristics at a Steady State
Pri
mar
y p
ress
ure
, bar
Secondary pressure, bar
0
Psol=6bar
Psol=6.3bar
Psol=2bar
Psol=4bar
40
30
20
10
10 20 30 400 50
7
0 10 20 30 40
Secondary pressure,bar
20
10
0Pri
mar
y p
ress
ure
, bar
40
30 i = 0.5
i = 1.0
i = 2.5
P-line
springScentss
PcentppSP FFPA
FPAFF
*
*
/
SSP
SPP PAA
FFPlineP /
1/
0.6
0.7
0.8 1
1.3
1.6 2
2.4
84 0
0.3
0.6
0.9
0
0.5
1
1.5
2
2.5
Thrust ratio
Speed ratio
Torque ratio
2.5
2
1.5
1
0.5
0
0.90.6
0.300.
6
2.51
Speed ratio
Torqueratio
Thrustratio
SP FF /
8
Prediction of Shift Performance by P-line
10 20 30 400
Pri
mar
y p
ress
ure
, bar
Secondary pressure, bar
0
Psol=6.3bar
Psol=2bar
40
30
20
10
50
Pup
Pup
Pdown
-Pup
Pdown
Pdown
A
B
CShift speed at B is the
fastest among the
three points, A, B
and C
9
Prediction of Shift Performance by P-line
Time, sec
2
1.5
1
0.5
0
Sp
ee
d r
ati
o
2.5
3
1.0 2.0 3.00
A
BC
2
1.5
1
0.5
0
2.5
3
A
BC
Simulation
Experiment
10
Experiments for Ratio Control Performance
CVT Test rig
11
Block Diagram of Ratio Control with PID Control
dutyRCSV
RCV
PID controller
Pp
id
CVTi
Psol
+
-
12
Control Performance
0
0.5
2
1.5
1
2.5
Sp
eed
rat
io
3T=5sec
0
0.5
2
1.5
1
2.5
Sp
eed
rat
io
3
Time, sec
0 5 10 15
T=8sec
idi
id i
There exist small response lag in the CVT ratio response
13
0 Ro
tati
on
al s
pee
d,
rpm
0
0.5
2
1.5
1
2.5
Sp
eed
rat
io
3 1200
1000
800
600
400
200
00 1 32 4 5
10
40
30
20
Time, sec
Pre
ssu
re, b
ar
6 7
50
Pp
Ps
Psd
i
id
s
p p
s
id
i
Psd
Ps
Pp
(a)
(b)0.6sec
Ratio Response for Stepwise Input of Ps
14
Steady State Pressure Characteristics with P-line
10 20 30 400
Pri
mar
y p
ress
ure
, bar
Secondary pressure, bar
0
Psol=6.3bar
Psol=2bar
40
30
20
10
50
Psol=2.5bar
Psol=3.5bar
15
Model Based Control
duty_conRCSV
RCV
PID controllerwith anti-windup
Pp
id
CVTi
Psol
+
-
P-linePs
+
+
Steady state RCV model
Pp*
duty_FF
16
Model Based Control
0 10 20 30 40 Secondary pressure,bar
40
30
20
10
0Pri
mar
y p
ress
ure
, bar
(a)
0 10 20 30 40 Secondary pressure,bar
40
30
20
10
0Pri
mar
y p
ress
ure
, bar
(a)
00 20 6040 80 100
10
40
30
20
50
RCSV duty, %P
rim
ary
pres
sure
, bar
Ps=10bar
Ps=20bar
Ps=40bar
Ps=30bar
(b)
00 20 6040 80 100
10
40
30
20
50
RCSV duty, %P
rim
ary
pres
sure
, bar
Ps=10bar
Ps=20bar
Ps=40bar
Ps=30bar
(b)
17
Model Based Control
0 Ro
tati
on
al s
pe
ed
, rp
m
0
0.5
2
1.5
1
2.5
Sp
ee
d r
ati
o
3 1800
1500
1200
900
600
300
00 1 32 4 5
10
40
30
20
Time, sec
Pre
ss
ure
, b
ar
6 7
50
0
20
80
60
40 Du
ty,
%
100
Pp
Ps
Psd
i
DutyFF
s
p
(b) Model based controller
id
(a)
0 Ro
tati
on
al s
pe
ed
, rp
m
0
0.5
2
1.5
1
2.5
Sp
ee
d r
ati
o
3 1800
1500
1200
900
600
300
00 1 32 4 5
10
40
30
20
Time, sec
Pre
ss
ure
, b
ar
6 7
50
0
20
80
60
40 Du
ty,
%
100
Pp
Ps
Psd
i
DutyFF
s
p
(b) Model based controller
id
(a)
p
ss
i
id
PsdPs
Duty_FF
Pp
0 Ro
tati
on
al
sp
ee
d,
rpm
0
0.5
2
1.5
1
2.5
Sp
ee
d r
ati
o
3 1800
1500
1200
900
600
300
00 1 32 4 5
10
40
30
20
Time, sec
Pre
ss
ure
, b
ar
6 7
50
Pp
Ps
Psd
i
id
s
p
(a) PID controller(b)
0 Ro
tati
on
al
sp
ee
d,
rpm
0
0.5
2
1.5
1
2.5
Sp
ee
d r
ati
o
3 1800
1500
1200
900
600
300
00 1 32 4 5
10
40
30
20
Time, sec
Pre
ss
ure
, b
ar
6 7
50
Pp
Ps
Psd
i
id
s
p
(a) PID controller(b)
p
s
i
id
PsdPs
Pp
18
Conclusion
A P-line is proposed from the steady state relationship
between the primary pressure and secondary pressure
CVT shift performance is predicted using the P-line
Linear control algorithm such as PID type controller can be
used for the pressure control type CVT
A model based control algorithm is proposed
The model based control is able to provide improved tracking
performance and robustness