KIKS 2012 Extended Team Description
Kenji Inukai, Yasuyuki Iwauchi, Shoma Mizutani,
Takaya Asakura, Ryu Goto, Masato Watanabe and Toko Sugiura
Toyota National College of Technology,
Department of Electrical and Electronic engineering,
2-1 Eisei-cho, Toyota Aichi, 471-8525, Japansugi@toyota-ct.ac.jp
URL: http://www.ee.toyota-ct.ac.jp/~masa/2012/kiks2.htm
Abstract. This paper presents a detailed description of KIKS in addition to theteam description paper of small size league in RoboCup 2012. Our robots and systems are designed under the RoboCup 2012 rules in order to participate in the RoboCup competition. The major improvements in this year are the enhancement ofthe performance and robustness of wheels, dribbling device and electrical circuit.
Keywords: RoboCup, small-size league, engineering education, global vision

1. Introduction
Main purpose of our participation to the RoboCup world competition is confirmation and evaluation of the results of the PBL (Project Based Learning) experiments.
The creative minds of students are educated using the robot contest held in our department every year. In the RoboCup world competition, our team has continuouslyparticipated since 2004. We came in the top 4 in Singapore and Istanbul. Since we areaiming for the higher position in this year, further improvements has been done.
Robot's performance was improved by replacing to brushless DC (BLDC) motor atlast year. But, we found the durability problems related to wheels through the competition. The dribble device was also in poor condition. So, we redesigned whole mechanical parts, and especially tried to replace the parts of wheel and dribbling device.
The main topics of developed system in 2012 are following terms,・Improvement of the wheels
・Improvement of the dribbling device
・Improvement of the circuit for BLDC motors and high voltage charger

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2. Hardware of the robot

Fig. 1 Overview of 2012 model

WeightTable 1. Specification of the 2012 version
2012 version
2.3kg

Main material

Aluminum alloy

Driving motor

maxon EC45flat (30Watt)

Gear ratio

3.6 : 1

Wheel diameter

56mm

Number of solenoids

Straight kick: 1
Chip kick: 2

Straight kick power

Ball speed of 8[m/s]Chip kick power

3.0m away from robot

The Overview of 2012 model is shown in Fig. 1. The basic configuration of a 2012
model is common with the 2011 version. It has been made the improvement to thedribbling device, chip kick device and bearing of wheel in 2012 model.
We made the omnidirectional wheels ourselves. We also use the brushless motors(maxon EC45 flat) for the driving motor, as in many teams. For the dribbling device,
we also use the brushless motor (maxon EC-max22). Each robot has three solenoids.
One is for straight kick and the other two are for chip kick. The robot is able to shootthe ball at a speed of 10[m/s], however, it is down to 8[m/s] to keep to the regulations.
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The height of the robot is 148[mm] and diameter is 178[mm]. The specification of therobot is summarized in Table 1.
2.1 Robustness improvement of the wheel
In RoboCup2011, many problems were occurred by hard collision in play. Especially, the wheels were badly damaged to the flange of the bearing. Figure 2 shows
the bearing used in the wheel. (a) and (b) show the normal and broken one, respectively. More than 20 bearings were damaged in the game of last year. This fact may
be caused a serious problem in rule of 2012. Because the direct free-kick will award
to opposite team, in case the parts of our robots fall on the field and it results in a
disadvantage of opposite team. Anyway, we need to solve quickly this problem.

(a)(b)

Fig. 2 Bearings used in wheel of 2011 version, (a) normal and (b) broken
Figure 3 (a) and (b) show the 2011 and 2012 version, respectively. In 2011 version,
the external thrusting forces give the damage to flange of the bearing. Therefore, in2012 version, we replace the bearing with the larger bearing with no flange to counterthe influence of external forces. Incidentally, the cost was also decreased. Now we'reexamining the many facets for the robustness of this new wheel. A part of experimental results is shown in Table 2. An aluminum solid of 2.4kg is fallen down perpendicularly from the position of 50cm height to the center of the side-face in wheel.
We verified the practical effectiveness by evaluation of repeat count until crash. As aresult, it seems fairly good performance.

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(a) 2011 version(b) 2012 version
Fig. 3 Structure of the wheel (Cross-sectional view of 3D CAD)

Table 2. Confirmation of the durability of new wheel
Repeat count until crash2011 version
42012 version

over 10

2.2 Optimization of dribbling device
In 2011, we changed the dribbling brush motor into brushless one (maxon ECmax22) to give the powerful backspin to the ball. But, in current mechanism of dribbling device, it is occurred the vibrational oscillation from time to time when the ballis rotated at high speed. The failure that was not able to hold a ball resulted from thevibration. It means that it is not necessary with high speed of dribbling device. So, we
tried to optimize the parameters for the dribbling device by using the Solid Works
Motion as an aid to the analysis. We investigated about the suction force of the dribbling device. It is evaluated by the height of the roller and its diameter as the parameter. When the vibration is occurred, there is also vibrational oscillation in electricalcurrent of circuit. So, we fabricated the experimental device to find the optimum value mentioned above. Experimental device to obtain electrical current and suction
force is shown in Fig. 4.

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Fig. 4 Experimental mechanism for dribbling device

Suction force to the ball (N)Figure 5 shows the relationship between suction force to the ball and the roller'sheight in dribbling device. In Fig. 5 the suction force to the ball is increasing as increase of roller's height. On the other hand, the suction force is not changed muchunder the condition that the diameter of the roller increases doubly, as shown in Fig.
6. Summarizing the experimental results in limited condition, the diameter of theroller does not significantly affect to the suction force, and it is found that the roller'sheight from ground is more important factor.
Figure 7 shows the relationship between the variance of the electrical current andthe roller height. From Fig. 7, it is predicted that the variance of electrical current will
be getting worse if the diameter of the roller is over 18mm long. Therefore, we define
the roller's diameter and height from ground on the basis of these results.
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
034

35
36
Roller' height from ground (mm)37

Fig. 5 Dependence of suction force to the ball with the roller's height (the diameter of roller is fixed with 15mm)

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Suction force to the ball (N)

1.2
1
0.8
0.6
0.4
0.2
010

1520

Diameter of the roller (mm)Variance of electrical current

Fig. 6 Dependence of suction force to the ball with the roller's diameter (theroller's height is fixed with 35mm from ground)
0.018
0.016
0.014
0.012
0.01

12[mm] diameter

0.008

15[mm] diameter

0.006

18[mm] diameter

0.004
0.002
031

32
33
34
Height of the roller[mm]35Fig. 7 Relationship between the variance of electrical current vs. roller's heightfrom ground as the parameters of roller's diameter

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(b)

(a)

Fig. 8 Dribbling device, (a) 2012 and (b) 2010 version.
The dribbling devices are shown in Fig. 8. The 2012 model is developed based onthe 2010 version. The 2012 model in Fig. 8 (a) is different from surface material andthe diameter of roller compared with 2010 version in Fig. 8 (b). That is, silicone rubber was changed into polyurethane rubber, and the diameter of 10.5mm with A5056
material was changed into that of 4mm with SUS304 in 2012 model.

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3. Electrical design
The electronic circuit of KIKS is mostly same as last year. The new electronic circuits consist of two main boards shown in Fig. 9. They are main control unit and peripheral control unit. The main control unit includes the main CPU, power supply
circuit, wireless communication module, ball detecting circuit and dribbling motorcontroller. The peripheral control unit includes motor driver and voltage booster. The
major changes are motor driver and voltage booster circuit.

Fig. 9 Construction of electrical circuit in the robot

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3.1 Main Control unit
This unit includes the circuit for detecting a ball, power supply circuit and wirelesscommunication module. The SH7262 (SH-2A series of Renesas) is used for a main
CPU that communicate each PIC for the peripheral controllers, such as BLDC controller, voltage booster circuit etc. The CPU runs 144MHz (345MIPS) and has 1MB
RAM. Its performance is enough to achieve the precise control of the robot.

3.2 Wireless communication system
We have used the Digi’s XBee module for communication system between host
PC and each robot. The wireless communication's frequency is 2.4GHz band. TheXBee module is able to communicate faster than conventional wireless module. It is
possible to communicate up to 115200bps.

3.3 BLDC motor driver
An each robot has four BLDC motor driver circuits for omnidirectional moving.
The MCU of motor driver is dsPIC30F4011. This circuit is added electrical current
sensing system. So, it is possible to control torque of each motor. The motor speed of
the robot is controlled by PI speed control in MCU. This circuit is also used for dribbling motor controller.

3.4 Voltage booster circuit
The DC-DC converter is used for the solenoid to boost up the voltage. The input
voltage of 16V is converted to 200V output. This chopper circuit is controlled by PIC
in each robot. In the kicking device, the output voltage of 200V is charged in 4100μF
capacitor.
In last year the time to charge up to 200V from 16V is 5 seconds. To shorten thecharging time, we try to optimize the coil inductance and switching frequency. We
made experimental circuit to evaluate that parameter. The electrical circuit and result
are shown in Fig. 10 and Fig. 11, respectively. In Fig. 11, in the case of capacitor of4100μF and duty ratio of 80%, it found recharging time was decrease to 2.46 seconds.
Thus, we used the coil with 185μH and applied switching frequency of 6kHz.

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Fig. 10 Experimental circuit to evaluate the optimal inductance and switching frequency
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101μH

138μH

185μH

561μH

Rechaｒging time (s)

1210
8
64
205

10
15Switching frequency (kHz)2025Fig. 11 Relationship between recharging time and switching frequency withvarious coil inductances.

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4. Software design
The image of AI system is shown in Fig. 12. Software design is mostly same with lastyear, however, based on the modification of the rule, AI system was done minorchange. The overall software architecture is shown in Fig. 13. The software consistsof three threads, i.e., the Game Thread, the SSL-Vision Receiver Thread and the Referee Box Receiver Thread. Moreover, the Game Thread includes some modules. The
role of each module is described in detail below.

Fig. 12 Image of AI system

Fig. 13 Software architectureadfa, p. 12, 2012.
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4.1 Strategy system
Strategy system is improved from last year. The architecture of new strategy system is illustrated in Fig. 14. The strategy system consists of four modules called "Situation Analysis", "Strategy", "Formation" and "Action". They are defined as following.
4.1.1 Situation Analysis moduleThis module is located at top level in strategy system. This module plays the roleof analysis about the game situation from both position of the ball and robots on thefield and generation of the trial instruction command.
4.1.2 Strategy moduleThis module is located at below level of Situation Analysis module. The role ofthis module is to select the optimal next Formation module from result of analyzing.
For example, when the result of analysis is “Indirect Free Kick of Own team”, theStrategy module will select the "Indirect Kick Formation module". On the other hand,when the result of analysis is “Need to Defense”, the Strategy module will select the"Defense Formation module". Since the Strategy module has many strategy patterns,
it will be able to select the optimal Strategy module corresponding to the game situation.
4.1.3 Formation moduleThis module is located at below level of Strategy module. This module plays therole to decide Action module which should be performed by each robot in next.
4.1.4 Action moduleThis module is located at the bottom level in strategy system. The role of this module is to command the specific operations to each robot. The "Direct Shoot Action"for instance, is commanded to the robot for kicking a ball. Alternatively, the "WallDefense Action" means the robots move to the position defending the goal.

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Fig. 14 Construction of Strategy system

4.2 Path Planner
Destination of each robot is determined by the Strategy system. Path Planner is themodule to generate a route that avoids defense area and the other robots. The methodof generating route is followings. First, it generates the linear route that connects thecurrent position and destination. Next, it checks all of obstacle position. If there isobstacle on the route already generated, it is changed the route using an arc formed
with constant radius at around the obstacle as shown in Fig. 15. Then, if there is stillother obstacle on the route, the radius is increased until that can be avoiding obstacle.

Fig. 15 Route generation to avoid obstacleadfa, p. 14, 2012.
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In previous one, it was not able to generate a path on the condition that goes throughmiddle-point between current position and destination. So, we improved that to beable to go through for the arbitral point. In present one, it can make a path taking account of pass-points as shown in Fig. 16.
Destination
pass-pointpass-pointpass-point
Current Position of robot

Fig. 16 Image of path in present Path Planner

4.3 Speed Controller
Speed Controller calculates the data related velocity to send the robot based on current speed of the robot and the generated route. Speed Controller has several types.
Optimal type of the controller is selected corresponding to the role of robot.
Speed Controller was also improved with modification of Path Planner. In present
one, the coordination of pass-points is used as the information for generation of robot's velocity, angle and position etc.

4.4 Sender to robot
This module is used for sending the data to robot. In this year, we improved theprotocol to send the data. Figure 17 show the sender's protocol of AI system. While
the same command informations are sent to 5 robots simultaneosuly and each robot
recognized the necessary information from sent data by themselves in previous
system in Fig. 17(a), in present protocol in Fig. 17(b), the command information withunique ID number for each robot is sent. Thus, the information for one robot is sent atonce using their own inherent ID number. If there is accident for the robot in game,we can change quickly and simply the robot with unique ID number added tocommand information in present protocol. As the results, there is no need to worry,for example, about working doubly as keeper's robot by using incorrect robot'sadfa, p. 15, 2012.
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number. Moreover, There is no limitation for number of the robots in present
protocol.

(a) Previous protocol(b) Present protocol

AI SystemAI System

Fig. 17 Sender protocol of AI system. (a) previous and (b) present version

4.5 Control of kicking power
According to the 2012 rule, there is limitation of 8m/s for a ball's speed. In previous
AI system, it was not able to control the kicking power with precise adjustment. It
was only four steps. If there was necessary to make drastic revision of kicking power,
we had to rewriting the PIC inside the robot. Thus, it became possible to change thekicking power in 255 steps on AI system. As the results, it became possible to kickthe ball with accuracy and there is also no need to rewrite the PIC inside the robot.

4.6 Simulation SystemIn recent year, there is little difference amang the hardware in SSL teams. Therefore,
it is very important the performance of software. We have to construct more excellent
AI system in short period and effectively. Up to now, we have used the simulator that
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was given the minimum required function to debug AI system. Thus, we improvedthat to develop the AI system efficiently in addition of many function as shown in
Fig. 18. Especially, we introduce the recording system of game, referee system
instead of RefereeBox, and AI system for Enemy. This system give real gamesituation to AI system. As a results, we don’t have to use real robot in many times,
and can construct and evaluate the strategy in short time.

Fig. 18 Screenshot of Simulator

5. Conclusions
Our robots have been continuously improving in every year. As the results, the durability and the performance of robots are getting better than previous year. Especially, the improvements of dribbling device are effective for construction of numerous
strategies and pass plays.
We hope that our robots will perform better in this coming competition.

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