SCYR 2010 - 10th Scientific Conference of Young Researchers – FEI TU of Košice
Model of Production Line with Multi-Motor Drive
Matúš HRIC
Dept. of Electrical, Mechatronic and Industrial Engineering, FEI TU of Košice, Slovak Republic
matus.hric@tuke.sk
Abstract— Production and finishing industrial lines occurs in
the industrial plants dealing with continuous production of
materials of various mature that are in form of a web, strip, fiber
etc. From control point of view they belong among complex
multivariable mechatronic systems where quality of output
products depends on quality of the control system. The main
variables to be controlled are usually the speed of the processed
material and of working machines. The contribution describes a
simplified physical model of a production line and its control
part. The model is used for teaching and debugging control
algorithms of complex systems that are presented by multi-motor
drive in this case.
Keywords—physical model, PLC, multi-motor drive
I. INTRODUCTION
Continuous production and finishing lines create essential
technological equipment in manufacturing production. They
are distinguished by mechanical coupling of individual
driving units in multi-motor drive through a moving web. For
teaching, explanation of mutual couplings and interactions in
the line, for practical realization of the control algorithms by
PLCs and for performing other laboratory experiments it is
advantageous to use physical models that enable to understand
easier principles of control strategy of such complex drive
systems [1].
II. PRODUCTION LINE WITH MULTI-MOTOR DRIVE IN PRAXIS
The term of multi-motor drive is used to describe all main
drives in the technological process used for transport of the
processed web which mechanically couples the drives [2].
One group of multi-motor drives is presented by drives of
continuous production and finishing lines. The lines are used
to perform various technological operations on a moving of a
metalic or non-metalic substance.
Typical arrangement of the production line is shown in
Fig.1. The mechanical energy of traction cylinders for moving
the web comes from electrical drives equipped by appropriate
control circuits (current-, speed- and position control). In the
most cases, the moving web makes elastic mechanical
couplings which leads to complexity of the system to be
controlled.
A generalized production/finishing line in Fig.1consists of:
a) The input section ensuring constant material flow – having
unwinder, drawing (tractive) cylinders, binding machine
(welder), input cartridge (to match with discontinuous
material inflow caused by coil exchange on the coiler spindle),
b) The technological section, with technological machines for
Fig. 1. Typical arrangement of a continuous production line and its parts
processing of the material and with combination of tractive Scylinders and working cylinders, material loops, etc.,
c) The output section, represented by output cartridge,
shearing machine to cut the material, and finally the winder.
The mechanical subsystem of the technological part is
driven by a multi-motor drive. Control system of the
electromechanical subsystem ensures a correct collaboration
of the drives satisfying technological requirements (constant
tension in the material independently from its speed, position
of the loop, etc.). It also contains some features of artificial
intelligence (automatic identification of material properties
and of other parameters, automatic tuning - adjusting the
controllers parameters to ensure quality of the final product,
etc.), [1]. As a supervisor here acts a superimposed control
system ensuring contact with a user: data input and collection
of technical and economical data from the technological
process. From system point of view one recognizes all basic
mechatronic subsystems here: the mechanical, electrical and
information ones (Fig. 2).
a)
b)
Fig. 2. Typical look-out of a production line (a) with multi-motor drive on
example of a hot strip mill and its generalized model block diagram (b)
SCYR 2010 - 10th Scientific Conference of Young Researchers – FEI TU of Košice
III. PHYSICAL MODEL OF A CONTINUOUS LINE
From the control point off view, the described system of the
continuous production line presents a complex MIMO (multi
(multiinput, multi-output)
output) system in which calculatio
calculation and setting
the controllers parameters for high control quality is enough
difficult and complex task. For teaching and expl
explanation of
phenomena occurring in the system, it is highly advantageous
to use eLearning instruments [2], [3] where phenomena can be
animated and slow down in order to analyze add understand
them.
Finally, verification of correct settingss of the controller
parameters causes a problem - they should be verified on a
real system. In industrial environment it is impossible to
perform any experiment from technical, safety and
economical reasons. Here, the simplified laboratory model of
a generalized industrial line (Fig. 3) presents a suitable
solution.
The mechanical part of the model consists of unwinder, 3
cylinders and winder: Altogether there are 5 drives to control.
The web consists of a film strip from celluloid material. In the
loops among
mong the machines there are placed swinging arms
that are tensioned by springs enabling to set up a tension in
the web. There are also position sensors sensing the ang
angle of the
arm. This arrangement enables the operator to check by sight
whether the web tension
nsion in sections among the neighboring
cylinders corresponds to the preset reference value. In the
bottom onn the left side there is a control panel with the
actuating buttons enabling to change modes of the line.
Fig. 4. Principal diagram of drive units control in the production line
During reconstruction of the model we replaced original
analogous speed sensors by incremental sensors and from this
reason also original analogous control was replaced by digital
control where the digital controller is programmed in the PLC.
Fig. 5 shows arrangement of the apparatus in the distribution
box (power converter, PLC, supply sources for IRC, auxiliary
switching relays and breaker apparatuses).
Fig. 5. A view into reconstructed distributing
distribut box of the physical model
The superimposed speed controller was realized by the PLC
Siemens S7- 400 with the technological card FM 458 that in
the programming environment S7 CFC (Continuous
(Continuo Function
Chart) from Siemens gives a possibility to interconnect and
set up common, or user’ss function blocks - similarly like it is
done in the Matlab-Simulink program.
program It should be noted that
the technological card FM-458
458 is used frequently in many
technological solutions in industry.
industry
Fig. 3. Physical model of a continuous production line
The driving cylinders in the line are driven by DC motor
drives that are supplied by the analogous Allan Bradley
converter. For the outer speed controller originally there was
used a microprocessor system MS-80
80 with A/D D/A
transducers
sducers and network of transputers, where several modern
control algorithms were debugged, [4].. Gradually, in line with
development of the IT and automation technologies
technologies, the
systems and its control part have been changed gradually.
After modernization only analogous AC/DC
DC converter and the
mechanical part remained.
IV. INNOVATED CONTROL OF A PHYSICAL MODEL
Control of electrical drives of a line requires using an
underimposed current controller for each drive implemented
in each converter module that are connected with an
overimposed speed controller.
Fig. 6. Output of controlling signals through limiters and D/A transducers
and their following addressing and input into a superimposed circuit
Fig. 7 shows scheme of a part
art of logical commanding that
was developed in PLC in the programming language
la
LAD.
SCYR 2010 - 10th Scientific Conference of Young Researchers – FEI TU of Košice
Fig. 9. Speed response and its simulated time course in the linear region at the
reference signal step corresponding to 5% of nominal value
Fig. 7. A Part of logical commanding of drives in the program STEP 7
and programming language LAD
ATION
V. PRACTICAL UTILIZATION
The physical model is used for laboratory experimentation
in several subjects of study, like:: Model
Models of Dynamical
Systems, Controlled Drives, Mechatronic Production Systems
Systems,
Control of Assembling Lines by PLCs,, Controlling and
Visualisating Systems, and Control of Mechatronic
Production Systems that are taught at the author’s department
at Technical University of Kosice.
The students practicallyy verify theoretical knowledge from
system dynamics fundamentals, control of electrical drives
drives,
design methods for drive controllers and their realization by
programming the PLC. They learn deeply the case studies
from field of multi/motor drives control and compare obtained
time responses from simulation with those go
got from the
laboratory model. Moreover, they have a chance to tune the
controllers and follow behavior of the systems at changed
system parameters.
A common example of the physical model utilization is in
case of teaching subject
ct of Controlled Drives. Fig. 8 shows
the speed response to a small reference value step. It shows
that the speed controller is tuned properly and its time
response corresponds to the simulated time course (on the
right side). Fig. 9 shows the speed response
se and large value of
the reference signal without using ARW connection. The
students have chance to modify the control program, to
change the controller parameters and to observe the system
behavior and responses to the changes.
Fig. 8. Speed response and its simulated time course in the linear region at the
reference signal step corresponding to 5% of nominal value
VI. CONCLUSION
The presented physical model of a continuous production
line containss all features of mechatronic systems and it offers
a unique chance for students to understand control principles
of complex drive systems with multi-motor
multi
drives. Moreover
it offers a safe experimentation on modern control systems
presented by PLCs, [5]. At their programming the students
performs experiments on the most modern automatic
equipments that causes a secondary effect for the graduates
from the concerned study program – increasing of their value
and competiveness on the labor market.
The originall model was recently substantially renovated
and we continue in this renovation by exchanging of the gears
among the motors and driving cylinders. The previous gears
having large backlash will be exchanged for planed gear with
the backlash of 2’ which will give chance to employ a more
precise control and thus to implement more complex
algorithms .The physical model also suitable for research at
design and verification of new control structures and
algorithms for HIL (Hardware-In-the-Loop)
(Hardware
simulation that
have recently become a standard at verification of
mechatronic systems control
REFERENCES
[1] BRANDENBURG, G. – WOLFERMANN, W.: State observers for multimulti
motor drives in processing machines with continuous moving webs,” in
Proc. Power Electronics and Applications Conf. (EPE’85), Brussels,
Belgium, 1985, pp. 3.203–3.210.
[2] JEFTENIC, Borislav – BEBIC, Milan – STATKIC, Sasa: Controlled
Multi-Motor
Motor Drives. In: International Symposium on Power Electronics,
Electrical Drives, Automation and Motion, SPEEDAM 2006.
20
23. 26.5.2006, pp. 1392 – 1398.
[3] FEDÁK, Viliam – FETYKO, Ján – REPIŠČÁK, Martin: Computer
Supported Education for Industrial Mechatronics Systems, In: Proc. of
Computer Based Learning in Science Int. Conf., CBLIS 2005, Zilina, 2.
- 6.7.2005. ISBN 9963-607-63-2,
2, pp. 19-27.
19
[4] FEDOR, Pavol – Perduková, Daniela – Timko, Jaroslav: Study of
Controlled Structure Properties with Reference Model. Acta Technica,
ČSAV 46, 2001, pp.167-179.
179. ISSN 0001-7043.
0001
[5] Virtual
Laboratory
of
Mechatronic
Systems
Control:
Control
http://andromeda.fei.t uke.sk/, (in Slovak).