Control of a Driveline with a Slipping Clutch
Andreas Myklebust, Lars Eriksson, Lars Nielsen (Vehicular Systems, LiU)Karl Redbrandt, Henrik Flemmer (SCANIA CV)
Integrated Powertrain ControlThe behavior of a vehicle is not only controlled by the engine. There
are several actuators available in a vehicles driveline (automatic clutch,
Automated Manual Transmission (AMT),. . . ) that can be used to affect
the vehicle drivebility. By using these different actuators in an integrated
manner with common control targets, performance and comfort benefits
can be achieved. Scania acts as industrial partner in this project and
supplies hardware and specific problem formulations.
Control of a Driveline with a Slipping ClutchThe use of an automatic actuator for the clutch gives new opportunities
for controlling the engine and driveline. Several applications would ben-
efit from advanced clutch control. For example start and stop strategies
for heavy trucks can be employed and in addition clutch control can be
utilized in AMTs to reduce the time for gear changes, which is a crucial
parameter for preventing stall in heavy trucks during hill climbing. Fur-
thermore it is possible to use clutch control to damp oscillations in the
driveline, e.g. through micro slip.
Oil Reservoir
Electric Motor
xm
x
x0
klinkagexcor
ICETransmission Shaft
Throwout Bearing
Diaphragm Spring
Piston
Torsional Spring
Push Plate
Friction Pads
Cushion Spring
Flywheel
Clutch Model
Original data
4 5 6 7 8 9 10 11 12
0
500
1000
1500
Piston Pos. [mm]
Clu
tch
To
rqu
e [
Nm
]
Time [s]
20
40
60
80
Temperature compensated
4 5 6 7 8 9 10 11 12
0
500
1000
1500
Double Exp. Corrected Pos. [mm]
Clu
tch
To
rqu
e [
Nm
]
Time [s]
20
40
60
80
Left graph shows data of the torque drift when energy is dissipated into
the clutch. Right graph shows the data after the position has been cor-
rected for temperature effects using the clutch model developed in this
project. The clutch model is a linear temperature model together with a
linear thermal expansion.
Observer
0 200 400 600 800 1000 1200 1400 1600
0
200
400
600
Clu
tch T
orq
ue [
Nm
]
Modeled
Measured
Observed
150 200 250 300
300
400
500
600
0 200 400 600 800 1000 1200 1400 160037
38
39
40
41
Ze
ro P
ositio
n [m
m]
Time [s]
Measuredwhen meas.EstimatedModelx4
0 200 400 600 800 1000 1200 1400 1600
50
100
150
Time [s]
Te
mpera
ture
[C
]
engine
mod. body
mod. hous.
mod. disc
obs. body
obs. hous.
obs. disc
An Extended Kalman Filter has been built in order to handle unknown
initial values and wear. The observer can start to converge before the
clutch is being slipped by using the available measurement of x0, see
figure to the left.
Driveline Model
Me
12Fdr
12Fdr
Measurement from a Scania truck compared with open-loop simulation
of the model. Driveline oscillations are modeled and capture both the
amplitude and frequency of those seen in experimental data.
Future WorkThe next step is to use the observer when developing a micro-slip con-
troller. Micro slip is when the clutch is controlled to be slipping all the
time, but with a very low slip in order to avoid over heating and unnec-
essary wear of the clutch.
PublicationsMyklebust, A. and Eriksson, L. (2012a). Road slope analysis and filtering
for driveline shuffle simulation. In 2012 IFAC Workshop on Engine
and Powertrain Control, Simulation and Modeling.
Myklebust, A. and Eriksson, L. (2012b). Torque model with fast and
slow temperature dynamics of a slipping dry clutch. In 2012 IEEE
Vehicle Power and Propulsion Conference.
Myklebust, A. and Eriksson, L. (2013a). The Effect of Thermal Expan-
sion in a Dry Clutch on Launch Control. In 7th IFAC Symposium
on Advances in Automotive Control.
Myklebust, A. and Eriksson, L. (2013b). Modeling and Estimation for
Dry Clutch Control. Licentiate Thesis.
Myklebust, A. and Eriksson, L. (2013c). Modeling, observability and es-
timation of thermal effects and aging on transmitted torque in a heavy
duty truck with a dry clutch. Submitted to IEEE/ASME Transac-
tions on Mechatronics.
http://www.linksic.isy.liu.se/LINK-SIC Linkoping Center for Sensor Informatics and Control — A Vinnova Industry Excellence Center
