Multicriteria Analysis of the Robotic Systems Autonomy Using Fuzzy
Calculations
Sergey Sokolov
a
and Vladimir Sudakov
b
Keldysh Institute of Applied Mathematics of Russian Academy of Sciences, Miusskaya sq. 4, Moscow, Russia
Keywords: Robotic Systems, Degree of Autonomy, Multicriteria Analysis, Fuzzy Areas, Preferences, Unification.
Abstract: Against the background of the ever-increasing needs for robotic systems (RS) with an increased degree of
autonomy and the emerging transition to their widespread use, the need for technologies for quality
assessment and multi-criteria analysis of the autonomy degree of such devices is becoming more urgent. The
article describes the current state of issues assessing and comparing the degree of autonomy of unmanned
systems using the vector criterion. Well-known estimates of the degree of autonomy are given. The existing
classification system distinguishes between informational and intellectual autonomy, which are considered in
close connection. Solutions are proposed that make it possible to formulate estimates of the autonomy degree
of robots in various areas of economics based on the theory of fuzzy sets. Based on the method of fuzzy areas
of preference, it becomes possible to obtain estimates of the degree of autonomy, taking into account the
judgments of the decision-maker. One of the positive consequences of this approach is the unification of
formulations and solutions in the tasks of information support in the RS, which, in turn, facilitates interaction
between users, customers and developers.
1 INTRODUCTION
The International Federation of Robotics (IFR)
defines a robot as a working mechanism that is
programmable along several axes with some degree
of autonomy and is capable of moving within a
defined environment to perform assigned tasks (IFR,
2015). From this definition, it follows that the
essential features of the concept of “robot” (i.e.,
criteria for the analysis of mechanisms created in
different historical periods) are: autonomy, which
means that “a robot is able to interpret the
environment in which it is located and adapt to the
assigned tasks "(Kaysner et al., 2016); and the ability
to program it in several directions. Another common
definition among scientists and practitioners is the
following: a robot is “any machine capable of
perceiving the environment and reacting to it based
on independently made decisions” (Nesmelov, 2022).
Thus, the key difference between robots and other
machines is considered to be “autonomy”: the robot
is able to interpret the environment in which it is
located and adapt to the assigned tasks. Robots are
a
https://orcid.org/0000-0001-6923-2510
b
https://orcid.org/0000-0002-1658-1941
evolving from programmed automation to semi-
autonomous and more autonomous complex systems.
Fully autonomous systems will be able to
independently make “decisions” in their intended
environment and perform tasks without human
assistance. In general, we can say that the trends in
modern robotics are increasing their autonomy and
the ability to solve various problems through the use
of artificial intelligence. Among the known types of
autonomy of technical devices such as logistical,
informational, and intellectual (Ermolov, 2012), it is
intellectual autonomy that stands out, closely related
to informational autonomy, and necessary for solving
problems in a previously unknown, changeable
environment.
What should RS have in order to be classified as
autonomous, and what should it be able to do execute
what algorithms? Experts predict that in development
work to create special-purpose robots, in accordance
with existing trends, the following should be
implemented (Murphy, 2020):
increased resource autonomy;
modularity of construction and reconfigurability;
Sokolov, S. and Sudakov, V.
Multicriteria Analysis of the Robotic Systems Autonomy Using Fuzzy Calculations.
DOI: 10.5220/0012418200003636
Paper published under CC license (CC BY-NC-ND 4.0)
In Proceedings of the 16th International Conference on Agents and Artificial Intelligence (ICAART 2024) - Volume 3, pages 915-919
ISBN: 978-989-758-680-4; ISSN: 2184-433X
Proceedings Copyright © 2024 by SCITEPRESS Science and Technology Publications, Lda.
915
constructive and technological unification of
samples and their key functional components;
noise-resistant multi-channel means and systems
of information and control interaction and
identification;
intelligent software and algorithmic tools that
allow for recognition of objects and the working
environment, reflexive forecasting of the
development of events, planning of rational (optimal)
behavior, and, as a consequence, adaptively
controlled functioning of special-purpose robots in
uncertain, dynamically changing heterogeneous
application conditions;
intelligent software and algorithmic tools that
allow for the integration of different types of special-
purpose robots into a single group with subsequent
control of their joint actions in similar,
heterogeneous, and mixed combat formations;
intelligent systems for human-machine interface
and decision support for operators controlling
special-purpose robots when solving combat (strike,
fire), support and special tasks.
Various criteria for autonomy are found in
publications, for example, the Society of Automotive
Engineers (SAE). To help automotive engineers,
governments, and insurance companies better
understand this new technology, SAE has defined six
(including no autonomy) levels of automotive
autonomy (SAE, 2023):
Level 0: Not at all autonomous; the driver has sole
control of the vehicle.
Level 1: One function is automated, but does not
necessarily use information about driving conditions.
A vehicle operating with simple cruise control will
qualify as Level 1.
Level 2: Acceleration, deceleration, and steering
are automated and use sensory data from the
environment to make decisions. Modern cars with
cruise control automatic lane keeping, or collision
mitigation braking fall into this category. The driver
remains solely responsible for the safe operation of
the vehicle.
Level 3: At this level, all safety functions are
automated, but the driver must still take control in an
emergency that the car cannot handle. An example
would be Tesla cars with the Autopilot feature
enabled. This is the most controversial level because
it requires the human driver to remain alert and
focused on the driving task even though the car is
doing most of the work. People would naturally find
this situation more tedious than simply driving a car,
and many in the autonomous vehicle community
worry that the driver's attention could be diverted
from the task at hand, leading to disastrous results.
Some automakers choose to skip Level 3 and go
straight to Level 4.
Levels 4 and 5: These are fully autonomous levels
where the car makes all driving decisions without
human intervention. The difference is that Level 4
cars are limited to a specific set of driving scenarios,
such as city, suburban, and highway driving, while
Level 5 cars can handle any driving scenario,
including off-road driving.
A similar autonomy scale has been adopted
among drone developers (PROXIMA, 2023). There
are five levels of UAV autonomy, based on the
principles of self-driving vehicle autonomy.
Level 0: No autonomy.
Level 1: Some systems are automated, such as
altitude control, but a human controls the UAV.
Level 2: Multiple simultaneous systems are
automated, but a human still controls the UAV.
Level 3: The UAV operates autonomously under
certain conditions, but a person monitors its
movement.
Level 4: The drone is autonomous in most
situations; a person can take over control, but this is
not necessary.
Level 5: The drone is completely autonomous.
Currently, the development of UAV technology is
between levels 3 and 4, where the drone can make
some decisions autonomously, but a person still needs
to observe the operation process of the device. The
main challenge in reaching level 5 is solving technical
problems and overcoming laws, regulations, and even
social acceptance in different regions.
Through the efforts of this ALFUS group, a clear
diagram has been proposed of what constitutes an
idea of the autonomy of a system and by what
indicators the autonomy of a particular system can be
assessed (ALFUS, 2004).
Autonomy indicators (sets of metrics) for a
detailed model that determines the level of autonomy
are summarized in the “space” of autonomy.
Mission complexity can be measured using
indicators such as levels of subtask completion,
decision-making and collaboration, knowledge and
perception requirements, planning and execution
efficiency, etc.
The level of human dependency can be measured
using indicators such as interaction time and
frequency, operator workload, skill levels, robot
initiation, etc.
Environmental complexity can be measured by
the size of obstacles, density and traffic, terrain types,
urban traffic characteristics, ability to recognize
friends, enemies, bystanders, etc. The detailed model
of the ALFUS framework contains the following
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defining concepts:
Unmanned systems (UMS) autonomy touches
many technical areas. Task complexity and
adaptability to the environment are some of the key
aspects.
The nature of UMSs' collaboration with human
operators, such as levels of involvement and types of
interactions, is important to the possibility of
autonomy.
Performance factors such as mission success
probability, response time, accuracy, resolution, and
latency tolerance influence UMS autonomy levels
(Huang et al., 2003).
Work is currently underway to determine
measurement scales for the proposed metrics.
Decision-makers may be guided by some complex
algorithms, as opposed to simple weighted averages,
to determine the resulting levels of vehicle autonomy.
It is recognized that the level of autonomy is an
extremely complex issue. There are a number of
problems that require resolution. These include:
1. Clarification of quantitative indicators and
prioritization. Identification of coincidences and
conflicts between them along the three axes of the
proposed space.
2. Development of standard measuring scales for
metrics.
3. Create high-level definitions of levels of
autonomy for the summary or executive model.
4. Development of methods and plans for testing
and confirming the levels of autonomy of unmanned
vehicles.
5. Defining and installing a domain-specific
autonomy level model for selected programs.
In addition, it is necessary to note the following
disadvantages of the proposed scheme:
Assessments based on indicators (criteria) are
often assigned by experts, but the method does not
take into account the degree of confidence of the
expert in the assigned assessment.
Criteria weights may also have a fuzzy (blurry)
character.
The use of weighted summation leads to implicit
mutual compensation of criteria, which means that
unsatisfactory scores for one criterion will be offset
by good scores for others.
Suggestions for overcoming some of these
problems will be discussed below.
2 METHOD
Based on experience in the development of robotic
systems (Sokolov, 2022) and analysis of methods of
applied mathematics in various fields (Sudakov and
Zhukov, 2023), methods for developing a generally
very productive and promising scheme of the ALFUS
group based on replacing the weighted summation of
point estimates with fuzzy judgments are proposed.
Let a vector of fuzzy values for autonomy
assessment criteria be given:
𝑋=
(
𝑥
,𝑥
,𝑥
…𝑥
)
,
(1)
where 𝑥
- the value of the fuzzy j-th criterion is
characterized by the membership function:
𝜇
𝑥
, 𝑥
∈𝐷
,
(2)
where 𝐷
is the domain (set of possible values) of the
j-th criterion.
If the value of the criterion cannot be determined,
this is complete uncertainty:
∀𝑥
∈𝐷
,𝜇
𝑥
=0.5
(3)
If the criterion is “not fuzzy”, then 𝜇
𝑥
=1, for
some 𝑥
=𝑥
and ∀𝑥
𝑥
𝜇
𝑥
=0.
Any other 𝜇
𝑥
specified on the coordinate grid
with the required degree of detail are acceptable.
Let the permissible levels of autonomy for objects 𝑂
,
𝑖=1,𝑛
be given. The solution to the problem of
determining the level of autonomy is based on the
construction of expert rules for the product type:
If some subset 𝑥
,𝑥
,𝑥
…𝑥
takes certain fuzzy
values, then 𝑋∈𝑂
.
This rule does not clearly assign an object to one
level of autonomy. It only redistributes the object’s
membership function to the set of all numbers of
autonomy levels. In fuzzy form, this implication
looks like this:
𝑝
(
𝑖,𝑥
,𝑥
,𝑥
…𝑥
)
=min
in
f
𝜆

(
𝑥
)
,𝜇
(
𝑥
)〉
,
(4)
where 𝜆

(
𝑥
)
belongs the value x to level 𝑂
for
variable j.
Next, we can move to a “not fuzzy” statement by
choosing the most possible level of autonomy:
𝑖
=argmax
𝑝
(
𝑖,𝑥
,𝑥
,𝑥
…𝑥
)
(5)
If the values of the characteristics are listed in
products through a fuzzy disjunction, then formula
(4) will take the form:
𝑝
(
𝑖,𝑥
,𝑥
,𝑥
…𝑥
)
=max
in
f
𝜆

(
𝑥
)
,𝜇
(𝑥)
(6)
Multicriteria Analysis of the Robotic Systems Autonomy Using Fuzzy Calculations
917
This method of specifying fuzzy membership
requires specifying expert judgments at the time of
estimating RS.
In addition to fuzzy class affiliation, it is
necessary to determine the degree of interest in the
corresponding levels of autonomy. This assessment
depends on the current environment in which the RS
operates, as well as on the priorities of the decision-
maker.
If the criteria are independent in preference, then
the standard fuzzy weighted summation procedure is
applied.
The level of autonomy is calculated using the
standard weighted sum formula:
𝑃
=𝑊
𝑋


,
(7)
where 𝑋
is the fuzzy estimate of the i-th RS
according to criterion k, and 𝑊
is the fuzzy
importance of criterion k, 𝑃
is the final interest in
objects of class i.
The rules for summing and multiplying fuzzy
numbers are carried out based on the principle of
communication. Membership function corresponding
to the operation:
𝜇
(
𝑦
)
=sup
,
,…
:
(
,
,…
)
Θ
𝜇
(𝑦
)
,
(8)
where η is the operation that needs to be applied (in
the case of calculating 𝑊
𝑋

is the product, and for
calculating
𝑊
𝑋


is the sum), 𝑦
are the values
to which the required operation is applied, 𝜇
(𝑦
) is
the membership function of fuzzy values, 𝜇
(
𝑦
)
is
the membership function for the result of applying the
operation η. Θ is the intersection operation for
membership functions. In this work, this is min, but
there are other varieties of this operation. Let us
denote the membership function of the resulting fuzzy
weighted sum as 𝜑
(𝑦).
To calculate the final level of autonomy, the clip
function is calculated for all possible levels, taking
into account their priorities, and their further fuzzy
combination:
𝜌
(
𝑦
)
=max
min
𝑝
(
𝑖,𝑥
,𝑥
,𝑥
…𝑥
)
,𝜑
(𝑦)
(9)
If fuzzy estimates of autonomy levels are obtained
for several RSs that need to be compared, then a fuzzy
comparison procedure is constructed or
defuzzification is performed:
𝑦
=
𝑦𝜌
(
𝑦
)
𝑑𝑦
𝜌
(
𝑦
)
𝑑𝑦
(10)
This approach will allow:
provide decision makers with tools for
formalizing qualitative judgments about the degree of
autonomy in tasks with a high dimension of the
criterion;
allows further assessment of the degree of
autonomy in automatic mode, i.e., the RS ranking
process will occur quickly and, possibly, without the
involvement of the decision maker, but taking into
account his preferences;
take into account preference dependencies
between the components of the vector criterion. As a
result, it is possible to identify and eliminate
situations where RS with an unacceptable level
according to one criterion receives a high integral
assessment at the expense of other criteria;
ensure the distinguishability of RS in the case
when criterion scales are subjected to artificial
discretization in order to replace continuous scales
with point scores.
To the complex “autonomy space” proposed by
the ALFUS group, we add scalar indicators:
qualification (mandatory program - admission to
evaluation, comparison or competition) of a robot:
what does a qualified device have?
statement of the problem: division into classes:
which class of problems can be solved (with what
amount of a priori information);
quality of problem solution (consumed computing
resources, time, accuracy, reliability (response to an
unforeseen situation)).
In terms of developing methods and plans for
testing and confirming the levels of autonomy of
unmanned vehicles, we are preparing an approximate
program and methodology for testing technical vision
systems in the task of providing information support
for targeted movements of autonomous vehicles.
To set the mission of an unmanned vehicle with
subsequent decomposition and automatic translation
into functional tasks, we create lists of tasks - basic,
typical scenarios, or precedents for the use of
unmanned vehicles. In our work, we focus on ground
mobile robots (Sokolov, 2022). An example of use
cases for an autonomous mobile robot:
- surveillance of the area or object;
- reconnaissance of a given area;
- search for specific objects of interest, their
identification and precise localization;
- work with detected objects of interest.
The basic list of technological operations (TO) of
a robot is determined by the above precedents. TO
include:
- TO robot safety systems (preventing collisions
with obstacles and robot overturning);
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918
- calculated TO (construction of trajectories,
localization of objects of interest, construction and
correction of the map);
- TO practice commands or information-motor
actions (ensuring the fulfillment of specified modes
of operation of the robot).
One of the most challenging issues in assessing
and making comparisons of unmanned vehicle
autonomy is defining or establishing a domain-
specific level of autonomy model for selected
programs. An equally complex problem is the
problem of a weighted assessment of the totality of
quantitative assessments in the space of “autonomy”.
Assessing the combination of mission complexity
and environmental complexity is subject to a high
degree of uncertainty and complexity, which
significantly limits the application of quantitative
methods for comparative analysis. Therefore, in this
part of autonomy assessments, the use of a well-
developed cognitive modeling apparatus is proposed.
Fuzzy cognitive maps are a way of representing real
dynamic systems in a form that corresponds to the
human perception of such processes.
3 CONCLUSIONS
The degree of autonomy depends on the tasks that ned
to be performed. Qualitatively, the scope defined by
a set of parameters within which the system can make
decisions and act independently to achieve its goals
can be called the degree of autonomy. Robots with
full autonomy are preferred in many applications,
such as space exploration, logistics, and others. As the
analysis shows, an objective and constructive
assessment of the degree of autonomy of RS requires
the serious collective efforts of the entire robotics
community.
The use of fuzzy logic, methods of multicriteria
analysis of alternatives, and decision-making theory
will allow us to take into account the vagueness of the
judgments of experts and decision-makers in
problems of comparing different RSs in terms of the
degree of autonomy and other criteria, including
economic and technical indicators. On this path, in
particular, lies the construction of ontologies for
subject areas - areas of application of RS. The use of
ontologies will allow customers and users to unify
coordinate units along the axes of the “autonomy
space”, objectively and quantitatively compare the
degrees of intellectual and information autonomy of
RS and RS designers to quickly assemble successful
solutions among themselves.
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