=Paper=
{{Paper
|id=Vol-2281/paper-12
|storemode=property
|title=Net-Centric Internet of Things for Industrial Machinery Workshop
|pdfUrl=https://ceur-ws.org/Vol-2281/paper-12.pdf
|volume=Vol-2281
|authors=Vsevolod Kotlyarov,Igor Chernorutsky,Pavel Drobintsev,Alexey Tolstoles,Irina Khrustaleva,Lina Kotlyarova
}}
==Net-Centric Internet of Things for Industrial Machinery Workshop==
https://ceur-ws.org/Vol-2281/paper-12.pdf
Net-Centric Internet of Things for Industrial
Machinery Workshop
Pavel Drobintsev1 , Igor Chernorutsky1 , Vsevolod Kotlyarov1 , Lina
Kotlyarova1 , Alexey Tolstoles1 , and Irina Khrustaleva1
Peter the Great St.Petersburg Polytechnic University, Saint Petersburg, Russia
vpk@spbstu.ru
Abstract. The most promising way of the development of manufac-
turing automation systems of the future is usage of the network-based
control solutions as their basis. Ideally, these complex net-centric sys-
tems should use adaptive approach to planning of the manufacturing
scenarios and function with high reliability. There are several issues in
this field of work. The first one is that such systems operate on large
sets of parameters and are characterized by complex operability modes
controlled by a large number of criteria. The second one directed to the
small–scale manufacturing is labor intensity of preparation of operative
documentation for various technological processes. This paper describes
an approach to small-scale manufacturing workshop automation, which
can adapt to various technological processes on the fly and effectively
use the required resources.
Keywords: Network-centric control · Adaptive manufacturing · Indus-
trial Internet of Things · Multi-criteria manufacturing optimization ·
Reliable technological processes.
1 Introduction
Today the driving trend of the manufacturing of the future is Industry 4.0.
Its core principle is in organizing workshop automation basing on the network-
ing control which integrates information exchange among computer numerical
control (CNC) machines, robots and other terminal equipment with means of
smart operational and strategic control of technological processes through con-
trol nodes forming the so-called Industrial Internet of Things (IIoT). One of the
most demanded features of such automation systems is their ability to adapt
to various technological processes of the small-scale or single-part manufactur-
ing in the fields of machine building, processing of raw materials, assembly of
multicomponent products and so on [1].
Automation of small-scale net-centric manufacturing in machinery requires
solution of many tasks such as automated formalization of technological pro-
cesses (conversion of existing and new operative documentation into technologi-
cal paths of commands), distribution of workshop equipment, materials and tools
between technological paths, monitoring of concurrent processes of supply and
Net-Centric Internet of Things for Industrial Machinery Workshop 113
execution, analysis, network planning and manufacturing optimization consider-
ing miscellaneous criteria distributed among three levels of industrial network.
Reliability is achieved by applying proving methods in the processes of design for
identifying all behavioral scenarios of manufacturing workshop and monitoring
of automated technological processes.
2 Features of the Workshop with Network-Centric
Control
Fig. 1. Machinery workshop with three levels of network-centric control
The example of the machinery workshop with three levels of network-centric
control is given on the Fig. 1. The levels depicted are as follows:
1. The first level works as the base for controlling the technological macro-
operations of machines, robots and other terminal equipment;
2. The second level carries out technological processes (control of the execution
of sequences of technological macro-operations);
3. The third level manages multi-criteria hierarchical optimization and manu-
facturing planning of the technological processes (TPs).
The modern CNC machines are smart enough to automatically carry out the
complex action sequences if they have the required materials, tools and equip-
ment. Therefore, we can afford not to go in details of single action performed
by the machine and instead operate with sequences of single actions which form
114 P. Drobintsev et al.
the so-called macro-operations of, for example, making a surface of a workpiece.
Each macro-operation has a set of parameters defining its modes, constraints
and conditions.
Macro-operations are transmitted between objects on the first and second
control levels. The technologies of making of various details are described in
terms of optimized sequences of the macro-operations which satisfy multi-criteria
hierarchical optimization from the third control level. The network-centric work-
shop reliability is ensured in several following ways:
– Technological scenarios. The schedule of the workshop in the form of the
description of the set of concurrent behavioral scenarios consists of the con-
ditions of both the usual and alternative behaviors depending on the param-
eters and domains of the scenarios. With the means of symbolic verification
the fullness and resolvability of the behaviors derived from the optimized
schedule are proved operatively.
– Transport protocols. The reliability is achieved by monitoring the history
of interactions in the technological processes, detection and processing of
incorrect incidents.
– Continuous monitoring of the system states.
3 The Approach to Formalization of Technological
Processes of the Machinery Workshop
In the single-part and small-scale manufacturing [2] with the decrease of the
scale of production follows the trend of reducing the cost of the technological
preparations [3].
For the traditional small-scale manufacturing the attempt to decrease the
lead time of an order by reducing the degree of detail of technological prepara-
tions leads to an increase in the production cycle, as well as to a decrease in the
quality of work performance. In addition, the situation with planning is compli-
cated by the fact that the work “under the order” is difficult to predict even for
a small perspective, so the volume-calendar plan is a certain forecast based on
the statistics of past orders. It is quite natural that such a forecast cannot serve
as a basis for the formation of a detailed production plan.
The basis of the methodology for creating such a plan is necessary and suf-
ficient information support with an unambiguous and complete description of
the design and technology of the product, as well as the planned loading of
each production process object. From the total amount of design information for
planning purposes, the product structure and the specification for the assembly
units are required, which, when using automated processing in engineering, is
made in accordance with GOST 2.053-2006 [4].
3.1 Features of Solving the Problems of Small-Scale Manufacturing
Organization
In the approach proposed in this paper, the described problems were solved due
to the following factors:
Net-Centric Internet of Things for Industrial Machinery Workshop 115
1. The operative solution of the problem of multi-criteria planning on a super-
computer and operative recalculation of the current schedule of the workshop
in accordance with the information on the state of all objects of network-
centric production.
2. Usage of features of formalization of technological processes, in which the
construction of a set of electronic documentation for technological prepara-
tions for the production of the whole product is replaced by the assembly of
documentation from the database of its components.
Traditionally, the stage of the technological preparations for production is com-
pleted by the development of the so-called operating card which describes the
technological sequence of operations (in our case, macro-operations), necessary
for manufacturing the product (Fig. 2). Figure 2 shows the layout of the prod-
uct (a), the fragments of the parameter space tables (b) and the part of the
operating card for one part of the detail (c).
The conditions of each technological macro-operation are recalculated based
on the exact data from the result of planning. As a result, we get a huge variety
of possible options.
Fig. 2. Informational basis of the operating card
The proposed approach is based on assembling the technological documen-
tation of the product, for example, the operating card, from the documentation
for its typical components. Such components typically are geometric shapes of
the surfaces of details: cylinders, cones, parallelepipeds and the like. To process
each component its parameters such as the type of workpiece, material, variants
116 P. Drobintsev et al.
of the cutting tools and gear, machining modes, etc. are fixed in the database.
The database also fixes the restrictions on the use of the processing modes for
each component.
The implementation of the technology fixed in the operating card in network-
centric production is the transfer of messages (transactions) from the controller
to the object of the operation - machine, robot, automated warehouse or equip-
ment adjuster. On completion of the current operation, the object sends a mes-
sage to the controller and the request for the next operation. Thus, the implemen-
tation of technology is reduced to the exchange of messages in network-centric
production. A convenient means of formalizing message exchange for concur-
rently interacting objects is the standardized MSC language [5]. To encode the
macro-operation sequence, it is sufficient to automatically convert the operating
card to MSC notation. An example of such a transformation is shown in Fig. 3.
3.2 Features of Planning of Technological Processes
In this paper the planning phase of the technological processes is directed to
working on the following tasks [6–10]:
1. The first one is selection of optimal (rational) scenario of TP implementation
in accordance with time criteria considering concurrent work of equipment
and downtime due to waiting for equipment vacancy after executing previous
operations.
2. The second one is determination of resource reserves while executing separate
non-critical operations.
3. The third task is to ensure the greatest possible savings of resources in the
production of the same product range.
To formalize the technological process and create its appropriate structure, you
need to specify a number of sets, such as the set of products of a certain number
and the set of resources required for implementation. At the same time, in the
general model it is necessary to take into account the possibility of using different
workpieces processed on different equipment to produce one finished product.
The whole TP eventually boils down to execution of specific set of standard
actions (ai ), from delivery of workpieces and tools from warehouse to machines
to transition of produced goods of specific nomenclature to warehouse. Time
for all operations is specified. Some operations can be executed simultaneously.
Obviously downtime of equipment is not desired. Description of TP and specifi-
cation of set of operations (ai ) allows setting existing consequence links between
separate operations. For example, producing a detail on the machine is impos-
sible without delivery of corresponding workpiece from warehouse. At the same
time the machine shall be free (this is also an operation), as well as all required
manipulators for delivering and placing of the detail.
Technological table T (ai ) in the form of a matrix where number of rows
equals to number of macro operations (ai ) shall be created as a result. Each row
indicates what operations this operation is based on (for example, the machine
Net-Centric Internet of Things for Industrial Machinery Workshop 117
Fig. 3. MSC diagram corresponding to the sequence of macro-operations (the param-
eters of the messages are omitted)
is free, the workpiece and cutting tools are prepared and installed). Later op-
erations are based on other operations (for example, the machine has finished
processing of previous detail, adjuster arrived to set a workpiece, etc.)
Unlike standard approaches to modeling of TP and manufacturing [6–10],
network methods allow quite simple creation of the implementation chart of
technological process, analysis of the implementation, bottlenecks determination
and provision of the ways to optimize manufacturing cycle.
An important quality criterion of technological process implementation is the
time required for its complete execution. Network methods allow calculating this
time considering possibility of simultaneous execution of some operations and
create critical path. At the same time existing reserves of time and critical oper-
ations making impact on the overall time of technological process are evaluated.
At the same time if some operations do not belong to critical path and have
reserves of time, their requirements can be reduced which would save resources.
The most time consuming procedure at planning stage is the procedure of
technological table creation. A method of its creation based on principles of
dynamic programming is proposed. The idea of the method is the following.
Analysis of technological process is performed from its end, i.e. when all details
have been produced and placed in the warehouse for produced goods. A detail
should be delivered to the warehouse to place it there. This is only possible if
it has been processed, taken from the machine and placed on a pallet. For this
it has to be taken off by free manipulator and delivered on an empty pallet.
Manipulator can only be free if it has completed previous operation and so on.
So the process goes from its end to beginning which is required to create table
118 P. Drobintsev et al.
T (ai ) (Table 1). Each its operation can be started only after the end of the other
operations which it relies on (they are listed in the third column). This is the
only logical limitation to the process. And many operations can be performed
simultaneously. The dashes in the third column mean that these operations are
Table 1. Technological table T (ai )
№ Operation ai Operations which it relies on Execution times ti of operations ai
1 a1 - t1
2 a2 - t2
3 a3 ai , ..., ak t3
4 a4 aj , ..., am t4
. . . .
n an al , ..., ar tn
independent and can be started at any time. It is assumed that each of the
operations relies on operations with lower order numbers. This can always be
achieved by proper ordering of operations and their renumbering.
For the given technological process, the following direct optimization tasks
can be solved:
1. Determination of the total time for the implementation of the specific process
and a list of bottlenecks - its critical operations.
2. Determination of the time reserves for all non-critical operations in order to
further optimize the process.
3. Identification of the most “threatened” operations, the performance of which
is the most important.
The various goals of optimization are the essence of the planning and man-
agement of the workshop. For example, the task may be to minimize the total
time for the implementation of the TP by accelerating certain operations with
additional investments of necessary reserves. Optimization can be carried out
already at the design stage of a given TP. It is obvious that in the first place
critical operations are being accelerated. However, in mathematical models of
optimization it is necessary to take into account that when the TP is varied dur-
ing the optimization process, the operations that are not critical in the initial
version can become critical and vice versa. The following optimization tasks can
be formulated:
– Task 1. What amount of additional resources should be allocated so that the
total time for the implementation of the TP does not exceed the set value
of T0 and additional investments are minimal?
– Task 2. Another situation is tied to the redistribution of fixed resources
between individual operations in order to minimize the total time for the
implementation of the TP (optimal transfer of resources from non-critical
operations to critical ones).
Net-Centric Internet of Things for Industrial Machinery Workshop 119
– Task 3. It may happen that the calculated time T of the TP implementation
is less than the specified value of T0 . How to direct the available time reserve
T0 − T for saving of the resources and a corresponding improvement of the
technological process?
The result of the planning phase is formed as a schedule for work distribution
to the resources of the workshop (Fig. 4).
Fig. 4. A part of the schedule for the workshop
3.3 The Procedure for Automating the Creation of a Reliable
Behavioral Model of the IIoT System in the Process of
Symbolic Verification
The reliability of network-centric manufacturing in this approach is provided
through the systematic application of the following procedure in the process of
creating software for IIoT technological applications:
1. Creation of a multilevel formal model of technological scenarios for the ma-
chinery workshop production on the basis of an event-oriented approach.
2. Proof of the correctness of the formal model and fixation of the acceptable
ranges of parameters and attributes of scenarios corresponding to their cor-
rect behavior [11].
3. Proof of completeness of behavioral technological scenarios in the process of
symbolic verification [11, 12].
4. Generation of a set of behavioral scenarios covering all the requirements for
the technology description basing on a detailed formal model.
5. Generation of a set of control tests for a set of specified scenarios and pro-
vision of testing of the technological process with a mapping of the causes
and consequences of errors on the original model [13].
6. Analysis of the behavior of all operational modes determined by technolog-
ical scenarios, the calculation of acceptable ranges of parameters used in
120 P. Drobintsev et al.
behavioral scenarios, and the generation of protective rules that control and
prevent all oversteppings of behavioral scenarios beyond acceptable bound-
aries that appear due to incorrect input information, failures and defects
[14].
The generation of a technological application basing of a correct detailed model
guarantees that there are no unauthorized codes in the application, which con-
tradict the conditions of the correct behavior of the technological scenario when
it is implemented in a network-centric workshop.
4 Usage of the High Performance Computing for
Effective Solution of the Automation Tasks
As noted above, the problems of automated planning and management of dis-
tributed processes of network-centric manufacturing require significant comput-
ing power that can be realized on a high-performance computer. The most ob-
vious possibility to accelerate all the processes of preparation and management
of manufacturing is to realize them as parallel. For this, each step in the work
of the planning and reliability instruments should be presented in the form of
a distributed network of interacting processes. To implement the processes of
searching for optimal solutions in a vast space of possible options, verification,
generation, analysis and testing, the multi-core cluster of distributed architecture
is most suitable.
A rough estimate of the required computational resources is determined by
the following:
– The need to select the necessary parameters for cutting tools, workpieces and
processing modes. For example, information about the cutting tools and the
modes of their use are contained in reference books with thousands of pages,
and hundreds of alternatives for a particular option are available.
– Formalization of the technology of processing a workpiece in the form of
work on the set of its components requires the ordering and distribution
of technological operations into groups that do not require readjustment of
the CNC machine. In the process of automated formation of manufacturing
technology from stated groups, processing command lists are created with
regards to the type of equipment used. As a result, a technology model
is prepared for implementation on the unlimited resources of the modeled
workshop.
– Planning of real work is executed within the limitations of the workshop re-
sources - machines, automated delivery mechanisms and robots. Moreover,
this process takes into account many hierarchically ordered optimality cri-
teria, providing a balance between time and cost of production, equipment
loading, stock availability, etc.
– Execution of the created work plan requires continuous monitoring of the
states of all workshop equipment and immediate responses (in the form of
re-planning of work) to all events related to the violation of the plan.
Net-Centric Internet of Things for Industrial Machinery Workshop 121
Since we describe the approach to the implementation of small-scale manufac-
turing, the tasks of preparation, planning and execution of production work must
be solved quickly, ensuring changes in the workshop operations within minutes.
This requires organization of joint work for the workshop of 10-15 processing
facilities (machines, robots, storage) and about a thousand parallel computing
processes.
Theoretically, parallel launching will give linear scalability. However, there
are still limits on executing on CPU/server, because machine has limited number
of cores/threads. Therefore, you will only have some work running, while the rest
of it will wait for its turn. Model of Toolset for planning, Control and Monitoring
technology processes was deployed on the Supercomputer of Saint Petersburg
State Polytechnic University on Tornado cluster. It has 800+ TFLOPS of peak
performance, 656 nodes, each with 2 CPU Xeon E5-2697 v3 and 64 GB of DDR4
RAM. Installed OS is modified CentOS, scheduling engine is SLURM.
5 Conclusion
The proposed approach is developed and tested in the boundaries of the grant
on the topic ”Theory and technology of design and development of reliable and
efficient network-centric management of production processes of the Industrial
Internet of Things”. As a result, a working prototype of the software complex
was created, which is a model of a small-scale workshop. The main solutions
and features of the small-scale production workshop in the field of ship repair
were verified on the model. The obtained results confirmed the achievement of
the main goals formulated in the project. In 2019, it is planned to integrate a
software package in the workshop of a shipbuilding enterprise.
Acknowledgments. The work was financially supported by the Ministry of
Education and Science of the Russian Federation in the framework of the Fed-
eral Targeted Program for Research and Development in Priority Areas of Ad-
vancement of the Russian Scientific and Technological Complex for 2014-2020
(№14.584.21.0022, ID RFMEFI58417X0022).
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