Journal of Robotics, Networking and Artificial Life, Vol. 3, No. 1 (June 2016), 65-68

Conquest Oriented Robot Knowing Its Own Availability
Sho Yamauchi

Future University Hakodate, 116-2, Kameda Nakanocho,
Hakodate-shi, Hokkaido, 041-0803, Japan,Keiji Suzuki

Future University Hakodate, 116-2, Kameda Nakanocho,
Hakodate-shi, Hokkaido, 041-0803, Japan,
E-mail: yamauchi@fun.ac.jp, kjsuzuki@fun.ac.jp
www.fun.ac.jp

Abstract
Robot is designed for achieving specific task. However, robot is able to do much more things than it is expected byits own hardware. In this paper, concept of conquest oriented robot is proposed to know its availability systematically and autonomously. Algorithm of conquest oriented robot and its experimental result in simulation field for the
first step is shown in this paper.
Keywords: autonomous, conquest, robot, availability

1. Introduction
Robot is designed for achieving specific task. Cleaner
robot is designed to collect dusts in room and industrial
robot is designed to assemble some kind of merchandisein factory. These tasks are designed by human and theonly thing robots do is complete the tasks. Previously,
robot is just a tool to achieve some tasks that are hardfor human or tool for automation. However, robot cando much more things by their body even though thething is not expected to do by human. For example,
Cleaner robot with two wheels can push something aswell as cleaning. This means that the cleaner robot
might bring something heavy and might communicate
with human by pushing their hands, for example. Robot
has lots of possibility by their given body and this possibility is not limited to the purpose expected by human.
From these points of view, concept of conquest oriented

robot is proposed in this paper. Base algorithm to findwhat they can do by its body is proposed for the firststep and experimental result using the algorithm isshown.
2. Concept of conquest oriented robot
The purpose of conquest oriented robot is finding, increasing and maintaining available things of the robot.
Robot has its own available event in its existing environment (Fig. 1). In other words, conquest oriented
robot tries to increase event that robot can execute withhigh probability, increase the probability and maintainits events and probability.
Comparison between previous robot design and conquest oriented robot is shown in Fig. 2. Robot is designed to reach only one event, it means “task”, previously. However, if the task is changed, robot must be re-Published by Atlantis Press
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Sho Yamauchi, Keiji Suzuki

designed to achieve new task. On the other hand, conquest oriented robot researches its own availability
previously and it can change its task easily if the newtask is within its availability.
What is an advantage of conquest oriented robot? Ifrobot knows its own availability, robot is able to do
maximum work even though it does not know the task
preliminarily. If the task is unavailable, robot is able toknow it is unavailable by its given hardware. In thiscase, human should prepare another robot that has suitable hardware.

Fig. 1. Conquest oriented robot concept. Event space means aset of all the events that might happen in current environment.
Conquest oriented robot tries to extend a set of event that isable to happen at any time.

Fig. 2. Previous robot design and conquest oriented design. In
previous robot design, the specific event is focused and robot
tries to achieve the specific task. However, conquest orientedrobot tries to find “what it can do” and maintain those things.

3. Action Fragment
GenerationandVariable

ActionAs a unit of robot’s available event, action fragment isintroduced. Action fragment is a part of time-series dataof robot’s action as shown in Fig. 3. Action fragment F
is defined as.

  
F = [ x1 , x2 , x3 ,..., xn ](1)

 ai(1)  ( 2)  ai (1) xi      (n )   xi( 2 )  ai a xi ==    bi(1)  ( m)   ( 2)  xi   bi   
bi( nb ) (2)(𝑘)where 𝑎𝑖(𝑘), 𝑏𝑖 are k-th actuator output and sensor input
at time i respectively .

Fig. 3. Action fragment of conquest oriented robot. Action
fragment is made of time series data of sensors and actuators.

Use Fourier series expansion to generate various typesof time-series action for robot. Equation is as follows.

a 0 nmaxf (ωt ) =+ ∑ (a n cos nωt + bn sin nωt ) (3)2 n =1

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Conquest Oriented Robot Knowing

If coefficients 𝑎𝑛 , 𝑏𝑛 are changed periodically, various
types of wave would be generated and this wave is used
as actuator output of robot for generating variousactions. To find new action fragment, robot has to detect
whether the action fragment is different from all otherexperienced action fragments. It means that criterion tomeasure the difference between two action fragments isneeded. For this purpose, criterion G is introduced asfollows.

G ( F A ,F B ) =AMSS (F A ,F B )
s max

(5)

Flong = arg max{len(F)}(6)

where 𝑭𝑨 , 𝑭𝑩 are compared action fragments. Function
len() returns length of action fragment’s time series data.
Function AMSS() is also returns the value of AMSS
between two action fragments. AMSS (Angular Metrics
for Shape Similarity) [Ref. 1] is method to compare twotime series data and calculate similarity. AMSS assume
time series data as vector and calculate similarity by cos
similarity and dynamic programing. It can be applied totime series data that are different length. In criterion G,similarity is normalized and all the results can becompared with each other. The value of criterion G iscalled similarity rate in this paper. Robot stores newaction fragment if new action fragment is different
enough comparing with all the action fragments stored
already as follows.
For all i, if similarity rate 𝑟𝑖 satisfies conditionri = G (F, Fi ) <c acc _ l

Confirm the process of “accumulate” in simple experiment. Consider a robot in 2D physics simulation field
shown in Fig. 4. In this simulation field, a differential
wheeled robot and two objects are placed. The robot can
detect object in front of it and obtain the distance fromdetected object. It means that this robot has 1 sensor and2 actuators.

(4)s max = AMSS (F long ,F long )F∈{FA ,FB }4. Experiment(7)

then store action fragment F
where cacc _ l (0 < cacc _ l ≤ 1) .
The process to store new action fragment is called“accumulate” in this paper. “Accumulate” is consideredas the first step of conquest oriented robot.

Fig. 4. 2D physics experimental field. Red line indicates thesensor of differential wheeled robot. Two objects are also
placed.

Friction between wheels of robot and floor, objects andfloor exists. Robot starts “accumulation” in this fieldand store action fragments. All the fragments have thesame fixed length in this time. In this experiment, twotypes of action generating methods are applied. Onechanges coefficients in equation (3) periodically.
Another does not change coefficients. If coefficients arechanged periodically, various types of action of robot
would be generated and number of action fragments is
supposed to increase. However, action of robot islimited, so the number of action fragment is expected tobe saturated eventually. On the other hand, if coefficientsin equation (3) are fixed, generated action of robot is far
more limited and number of stored action fragment isexpected to be smaller. Experimental result is shown inFig. 5. Horizontal axis denote time step and vertical axis
means number of action fragments. “Update” is a casethat coefficients in equation (3) are periodically updated.
“Fixed” means coefficients in equation (3) are fixed.

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Sho Yamauchi, Keiji Suzuki

As expected, number of action fragment saturated inboth case. Also, as we expected, the number of action
fragment in “Fixed” case is smaller than “Update”. This
result means that criterion G for similarity rate works
properly and “accumulation” phase algorithm works
properly.

5. Conclusion
The concept of conquest oriented robot that tries toknow its own availability is proposed in this paper. For
the first step, algorithm of “accumulate”, the first phaseof conquest oriented robot algorithm, is proposed.
AMSS based similarity criterion is also introduced.
“Accumulate” phase process is confirmed by experiment using differential wheeled robot in 2D physics
simulation experiment field. We develop second andthird phase of conquest oriented robot algorithm for thefuture work.

References
1. Tetsuya NAKAMURA, Keishi TAKI, Hiroki NOMIYA
and Kuniaki UEHARA, AMSS: A Similarity Measure fortime Series Data, IEICE TRANSACTIONS on Information and Systems, Vol.J91-D, No.11, pp.2579-2588,
2008.
Fig. 5. Experimental result. Horizontal axis denote time steps
and Vertical axis denote number of action fragments..

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