=Paper=
{{Paper
|id=Vol-2556/paper14
|storemode=property
|title=Problems of Building the Intelligent Consistent Control Logic for Complex Technical Systems in Transport Industry (short paper)
|pdfUrl=https://ceur-ws.org/Vol-2556/paper14.pdf
|volume=Vol-2556
|authors=Andrey A. Tyugashev,Alexander P. Dolgintsev,Igor A. Molodkin,Sergey E. Adadurov
}}
==Problems of Building the Intelligent Consistent Control Logic for Complex Technical Systems in Transport Industry (short paper)==
https://ceur-ws.org/Vol-2556/paper14.pdf
Problems of Building the Intelligent Consistent Control Logic for
Complex Technical Systems in Transport Industry
Andrey A. Tyugashev Igor A. Molodkin
Samara State Transport Emperor Alexander I St. Petersburg State Transport
University University
Samara, Russia Saint Petersburg, Russia
a.tyugashev@samgups.ru ivs@pgups.ru
Alexander P. Dolgintsev Sergey E. Adadurov
Samara State Transport JSC “VNIIZHT”
University Moscow, Russia
Samara, Russia
dolgintsev@rambler.ru
lot of different devices. The next essential common
feature is a complex behavior in the external
environment with possible unpredictable events. The
very important problem related to the systems is
providing them with consistent control with the right
Abstract consideration of various kinds of complexity. The
paper is devoted to the attempts of analysis of the
We can review Railroad Transportation, various sides of this problem, and finding the ways of
Aerial manned and unmanned vehicles, and the possible solutions.
Spacecrafts as examples of a complex Each complex system is being built to perform a
technical system. Their subsystems contain particular role. We can suppose transport passengers
many devices, sensors, and other equipment. from one geographical location to another, generate
There is an important problem how to build electric power, manufacture the goods, etc. There are a
the intelligent real-time computer-based set of system goals to be achieved. For the systems in
control logic for such complex of the the Transport Industry, for example, trains, planes,
subsystems. The paper is devoted to this trucks these goals accompanied by the moments of
problem. We focus on mathematical modeling time (deadlines). Moreover, to achieve a goal at a
and finding the ways of synthesis and specific moment of time, it is necessary to execute
verification of consistent control logic. The some preparatory processes. Other processes should be
paper also presents some software tools executed after reaching the goal (for instance, cleaning
developed by the authors. of the cabin or the cargo body). So, the very important
aspect of complexity is a Real-Time mode [Tyu06]. In
1 Introduction many cases, the system should fulfil not just an abstract
‘tasks’, but the timed sequences of logically
There are many very complex technical systems in use coordinated and physically mutually dependent
nowadays in different areas. We can propose Railroad processes. Some of these processes have non-zero
Transportation, Automated Manufactories, Nuclear duration, so we must model them adequately. The
Power Plants, Spacecrafts [Koz98], etc. as good systems to be modeled have an active nature. It means
examples of such systems. Named systems have some the existence of the plan/schedule to be implemented.
significant common features related to the phenomenon In Aerospace Industry, such plan is being called as
of complexity. For example, one can note the complex ‘cyclogram’. Moreover, frequently there are physically
hierarchical structure; in fact, the system usually and logically founded restrictions not just for the
consists of the subsystems which, in turn, consist of a sequence of the processes to be executed, but for
synchronization of begins and ends of them. Some
Copyright c by the paper's authors. Use permitted under Creative
Commons License Attribution 4.0 International (CC BY 4.0). In: A. processes must have no overlaps in time, and the
Khomonenko, B. Sokolov, K. Ivanova (eds.): Selected Papers of the reasons for this issue could be very strong. These
Models and Methods of Information Systems Research Workshop, St. requirements could be formulated using the language
Petersburg, Russia, 4-5 Dec. 2019, published at http://ceur-ws.org of Real-Time Control Logic [Kav06].
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The additional aspect of the complexity of the control Usually, the control subsystem of the modern complex
logic is caused by the possibility of some unpredictable technical system uses computers running a special sort
events which might require change/adapt system’s of software – control software. In Aerospace Industry
plans to provide flexible reaction. The system must this software called ‘flight control software’. This
successfully complete the plan both in normal software issue commands to the onboard equipment
operations and in case of abnormal situations. In a coded as the sequence of electric impulses. Command
picture reflecting the cyclogram, the fact that this can means, for example, «Activate the device 2 of the
particular process has to be executed in a specific system 1 now» or «Switch the gyrodyne 2 off». The
situation only (for example, if some event happened) software name itself means this is a ‘soft’ entity having
can be shown by color [Tyu16]. Also, we can see the the appropriate level of flexibility to reconfigure the
duration specified for the processes continued in time. onboard apparatus to keep enough level of all kinds of
In Aerospace Industry this kind of plan/schedule is the required functionality during the whole mission
usually called a ‘cyclogram’, see Fig. 1. [Syg19].
Of course, the system works under the influence of the
environment. The required execution of the system’s
plans is being dependent on external factors. On the
other hand, the system’s outputs and activity change
the external environment due to physical engagements
(perhaps, with some time delay). We can state the
existence of the mutual influence between the system
and its environment. This specificity caused the
following requirement for the system. The control
means should provide control that can guarantee safety
during the completion of the pre-defined set of tasks
the complex technical system was built to execute.
The safety, in this case, means not only internal safety,
i.e. keeping the devices and subsystems in serviceable
Figure 1: Cyclogram/plan of real-time operations ‘healthy’ conditions, but also the external safety. We
mean that the system has its own influence on the
Of course, consistent control requires such features as external world, and we must keep various kinds of
dependability and flexibility. In case of some influence in defined borders. Moving objects should
emergencies caused by faults of the equipment, the not damage the humans or arbitrary external entity. The
system goals should be achieved anyway [Fi15]. This emissions of the enterprise must be within the specified
is possible due to the redundancy of the limits, and so on. The other side of this problem
equipment/apparatus. The designers of the complex connected with the accurate consumption of the
system provide structural and functional redundancy in available resources during the functioning. Each device
several ways. First, the duplication is widely used for requires particular resources, for instance, electric
critical mechanisms and aggregates. If some particular power. Numerous devices can be turned to various
device will be crashed, the control system should detect regimes with different levels of consumption of the
this abnormal situation and switch to backup one. In resources. The control rules of the named technical
other words, there is a very important ability of systems are being implemented by ‘control logic’.
intelligent cybernetic systems - reconfiguration. The very important issue is the necessity of presence in
Another successfully applied [Koz98] way to parry the control means of the complex technical system of some
device’s failures is to utilize functional redundancy to internal ‘reflection’ of the following aspects. First, we
use another subsystem in an abnormal situation. To do need a picture of the external environment and its
this, the control algorithms must ‘understand’ factors we should take into account when
functional abilities of the various kinds of installed implementing our plans. Second, we should have the
equipment and existence of the opportunities to use image of the current condition of the controlled system
another unit to execute some task instead of initially itself with the means to describe the level of
intended for this purpose. functionality/workability of our devices. And finally,
we must have the representation of the goals with the
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understandings which ones are already done and which restructuration. And finally, the set of goals to be
are waiting to be executed at which moments of time. achieved might be updated during the operations.
In this context, we can apply the well-known Ashby’s How we can describe the real-time control logic used
cybernetical Law of Requisite Variety: only a variety by these systems? When we are talking about the logic,
of control means can absorb a variety of controlled we suppose the usage of axioms and rules. Naturally,
complex system and its behavior. Or: the control we should utilize some reasoning based on the rules of
system’s complexity (both hardware and software) logic. What can we review as the ‘control logic’ of the
reflects the complexity of the controlled system itself. complex technical system? Rules can be formed as ‘IF
Hereby, we need to define the models for adequate {antecedents/assumptions} THEN {conclusions}. For
describing the presented complex systems with the complex technical systems working in real-time mode,
corresponding representation of the real-time control the best results could be provided by the timed versions
logic considering the requirements and restrictions of these rules, which can be specified in the following
stated above, and to find the methods for building this manner::
consistent control logic in practice.
a1(tu1)^ ¬ a2(t u2)^… aM(t uM) →A1(ta1)^A2(ta1)^… AN(taN) (1)
2 The Method
There are logical variables (with the values TRUE and
Let us outline the necessity of the following essential FALSE) on the left side of the formulae, and the
features for real-time intelligently and consistently actions on the right side. Some of the actions set or
controlled complex systems: clear the logical conditions, so after the application of
• Presence of internal reflection of the external some rule, the truth of particular conditions can be
environment, the image of the current condition of changed. The very important aspect of the complex
the system including information about the actual system interacting with the external environment by the
level of functional abilities of the installed devices physical processes is changing the conditions reflecting
– ‘image of itself’, and the knowledge about the the current situation, in time. As we presented above in
plan (schedule) including data about already (1), we have the conjunction of the conditions (some
completed tasks and goals to be achieved in future. with the logical negation) on the left side of the rule. It
• The ability of flexible self-reconfiguration based is possible to specify several rules with the same left
on an evaluation of the current situation and tasks part, so these rules can be used as connected by logical
to be executed OR (disjunction). Consequently, in accordance with the
• System’s control logic based on the real-time rules logical completeness of DNF/CNF form of logical
which might be flexibly updated and expanded. rules, we can declare the universalism of this approach
Druzhinin and Kntorov [Dru76] mentioned the levels for the description of any real-time control logic.
of complexity of cybernetical systems. The problem of the synthesis of the consistent control
• Deterministic S1 systems with the rigid logic requires performing the following transitions.
transformation rule input X into output Y Since we have the goals to be achieved by the system
• Stochastic S2 systems with the notable influence with the correspondent deadlines, we can then make
of random factors to results the transition to the required schedule (set of the
• S3 systems without well-defined rules of schedules for various scenarios depending on course of
transformation input into output events) of the actions (processes). Each action requires
• S4 systems implementing the plans and achieving some specific functionality. For instance, moving
the pre-settled goals objects need some abilities in navigation and some
• S0 systems with choosing its own goals and abilities in communications. Meanwhile, navigation
changing the structure and adaptive reaction for can be performed using GPS/GLONASS satellite’s
the inputs signals or using the inertial navigation system. A power
• Using this approach, the considered systems might supply is another kind of required functionality which
be classified as S0 systems. The reasons are the can be provided by different devices, for example by
following. First, we have the flexible control logic the batteries or by solar panels. So, we can realize the
taking into account the different situations transition from the process schedule to schedule of
implemented by control software. Second, we can necessary functionality. Then we should make a
state the presence of the possibility of self- transition from the functionality to the devices needed
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to provide it. At this moment, we have the schedule CL – control logic presented as a set of timed
(again, schedules for various scenarios) of the work of rules
the system’s’ devices. The next transition is the RS is the set of resources/emissions having
transition from this schedule to the set of rules of an impact on consistent functioning of the system with
control logic formulated as (1). And then we can the specified maximum allowed levels of
implement (by manual coding or by automated code consumption/emission
generation, see [Tyu162]) this logic implemented in the SC is the set of the constraints for right synchronization
control software. The reverse engineering problem is of the system’s processes in the above- presented form.
the problem of verification whether the logic Actually, the BA can be reviewed as the algebraic
implemented in control software corresponds to the system [Tyu06] with the relation of belonging the
goals and their deadlines. It supposes the transition device to a system, and there are relations between the
from the existing software modules back to control devices and their working modes, and between the
logic’s rules. We can use special procedures for the working modes, levels of provided functionality,
extraction of the control logic rules from the program resources and emissions. The restrictions for the
code by analyzing the software modules, then for the minimal required level of each kind of functionality
restoration of the aforementioned schedules, and then and maximal available levels of each kind of the
for checking if the required goals are being achieved in resources are the other essential constraint for the
time. consistent control logic along with the time restrictions
Consequently, the ‘consistency’ of the control logic To solve the problem we can use computer simulation
means: in a special software tool to calculate the consuming of
the resources and emissions for all mission time
• Correspondence to the set of the required duration. Another simulation mechanism can allow
conditions of synchronization, for example f1 << checking whether the levels of all kinds of required
f2, f3 CH f5, f1->f5->f7, prohibition of the functionality will be enough for achieving the system’s
intersection of particular processes f11 <> f8 (it goals even in case of arising of abnormal situations.
can be caused by the physical reasons, for The problem of verification of the control logic is
instance, if the spacecraft’s solar panel can shade checking whether 1) the specified set of rules
the lens of Earth Remote Sensing instrument) implements the schedule which guarantees to achieve
• Functioning without violation of the limits of the goals with compliance of their deadlines; 2)
available resources and allowed emissions available/allowed levels of resources and emissions are
• Dependability, i.e. the completion of the set of not violated, and 3) existing restrictions SC are not
required tasks should be guaranteed regardless of violated. In case of the abnormal situation caused by
device failures and happening of the unforeseen the fault of a particular device, the control subsystem
situations. should check the level of degradation of the
Whenever we have the schedule built starting from the corresponding functionality, and then issue a special
system’s goals or extracted from the control programs, command to activate the appropriate substitution.
its compliance with synchronization requirements can These rules must be a significant subset of the real-time
be verified using the physical sense of the operators << control logic rules.
(precedence in time), <> (prohibition of the
overlapping), СН (begin-begin link), СК (end-end
link), → (direct following), see the publications Conclusion and Future Work
[Kav06] and [Tyu16].
Further, we can define the complex technical system as The model for the description of the real-time control
the following tuple: logic for a complex technical system in the Transport
{BA, G, CL, RS, CA, CS} (2) Industry has been defined in the article. We have
Where BA is the set of the devices with the considered fundamental problems connected with the
correspondent set of their working modes; consistent control logic. The first problem is a problem
G is a set of goals to be implemented of verification, and the second problem is a synthesis
accompanied by the deadline for each goal of consistent real-time control.
FS is a set of the kinds of functionality When we consider the future work, we can underline
that the authors lead the development of special
83
software tools which allow verifying the control logic Journal of Computer and Systems Sciences
implemented in the source code of the control International. 45(2): 287–300, August 2006.
programs. To solve the problem of synthesis the logic
[Kav06] A. Kalentyev CALS technology in lifecycle
with compliance to conditions of consistency, we are
trying to utilize the power of modern Satisfiability of complex control programs / A.A Kalentyev,
Model Theories Solvers, see [Tyu18]. The screenshot A.A. Tyugashev Samara: Scientific Center of
of the one of the developed software prototypes is Russian Academy of Sciences, 2006. 266 p.
shown in Fig. 2. (in Russian).
Another perspective approach connected with the use [Tyu16] A Tyugashev Language and Toolset for
of constraint programming. In the past, we had a Visual Construction of Programs for
successful experience in the application of logic Intelligent Autonomous Spacecraft Control
programming the real-time control algorithms IFAC - PapersOnLine 49 (5), 120-125, May
[Tyu162]. 2016.
[Fil15] A. Filatov Structure and algorithms of motion
control system's software of the small
spacecraft / A.V. Filatov, I.S. Tkachenko,
A.A Tyugashev., E.V. Sopchenko CEUR
Workshop Proc. Proceedings of International
Conference Information Technology and
Nanotechnology ITNT 2015, Pp. 246-
251.2015.
[Syg19] Yu. Sygurov Method for modeling of
Spacecraft onboard apparatus and building of
consistent control logic with limited onboard
resources / A. Tyugashev, Yu. Sygurov,
Journal of Physics Conference Series
Figure 2:. Screenshot of the software prototype 1368:042032 November 2019.
The logic programs written in Prolog language allow [Dru76] V.B. Druzhinin. The problems of the
finding the appropriate parameters of the algorithm. systemology (the problems of the theory of
complex systems ) / V.B. Druginin,, D.S.
Acknowledgments Kontorov Moscow: Sovetskoye Radio, 1976.
296 p. (In Russian).
We acknowledge the colleagues from Samara Space [Tyu18] A. Tyugashev, Application of SMT solvers for
Centre and JSC Information Satellite Systems for the evaluation of Real-Time control logic of
many-years collaboration in the area of spacecraft fight spacecraft. / Journal of Physics: Conference
control software engineering, and the founder of this Series 1096 (1) January 2018
direction of researches, Anatoly Kalentyev.
[Tyu162] A. Tyugashev Visual Builder of Rules for
Spacecraft Onboard Real-Time Knowledge
References Base / 8th KES International Conference on
[Koz98] D. Kozlov. Control of Earth observation Intelligent Decision Technologies (KES-IDT
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