KIKS 2012 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 is used to qualify as participation to the RoboCup 2012
small-size league (SSL) about team “KIKS”. 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 of the performance androbustness of wheels, dribbling device and electrical circuit. The overviews ofthem are described.
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 continuously
participated 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

adfa, p. 1, 2011.
© Springer-Verlag Berlin Heidelberg 2011

2. Hardware of the robot
The basic configuration of a 2012 model is common with the 2011 version. We
made the omnidirectional wheels ourselves. We also use the brushless motors (maxonEC45 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 isfor straight kick and the other two are for chip kick. The robot is able to shoot the ballat a speed of 10[m/s], however, it is down to 8[m/s] to keep to the regulations. The
height of the robot is 148[mm] and diameter is 178[mm].

WeightTable1. 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 power3.0m away from robot

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 1 shows
the bearing used in the wheel. Fig.1 (a) shows the normal one and (b) shows the broken one. More than 20 bearings were damaged in the game. 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 ofopposite team. Anyway, we need to solve quickly this problem.

(a)(b)Fig.1 Bearings used in wheel of 2011 version, (a) normal and (b) broken
Fig.2 (a) shows the 2011 version and (b) shows the 2012 version after improvement. In 2011 version, the external thrusting forces give the damage to flange of thebearing. Therefore, in 2012 version, we replace the bearing with the larger bearing
with no flange to counter the influence of external forces. Incidentally, the cost wasalso decreased. Now we're examining the many facets for the robustness of this newwheel. 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 ofthe side-face in wheel. We verified the practical effectiveness by evaluation of repeat
count until crash. As a result, it seems fairly good performance.

(a) 2011 version(b) 2012 version
Fig.2 Structure of the wheel (Cross-sectional view of 3D CAD)

Table2. Confirmation of the durability of new wheel
Repeat count until crash2011 version
42012 versionover 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, wetried 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. 3.

Fig.3 Experimental mechanism for dribbling device
Figure 4 shows the relationship between suction force to the ball and the roller'sheight in dribbling device. In Fig.4 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.5.
Summarizing the experimental results in limited condition, the diameter of the roller
does not significantly affect to the suction force, and it is found that the roller's heightfrom ground is more important factor.
Figure 6 shows the relationship between the variance of the electrical current andthe roller height. From Fig.6, 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.

Suction force to the ball (N)

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)37Fig.4 Dependence of suction force to the ball with the roller's height (the diameterof roller is fixed with 15mm)

Suction force to the ball (N)

1.2
1
0.8
0.6
0.40.20101520Diameter of the roller (mm)Fig.5 Dependence of suction force to the ball with the roller's diameter (theroller's height is fixed with 35mm from ground)Variance of electrical current

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
031323334
Height of the roller[mm]35Fig.6 Relationship between the variance of electrical current vs. roller's heightfrom ground as the parameters of roller's diameter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.7. 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. Themajor changes are motor driver and voltage booster circuit.

Fig.7 Construction of electrical circuit in the robot

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 ispossible 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 to boost up the voltage used for the solenoid is changed
from last year. To shorten the charging time, we optimize the inductance and switching frequency. In last year the time to charge up to 200V from 16V is five seconds,
but that time of this year is shortened 2.7 seconds.
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 ischarged in 4100μF capacitor.

4. Software design
Software design is mostly same with last year. The overall software architecture isshown in Fig 8. The software consists of three threads, i.e., the Game Thread, theSSL-Vision Receiver Thread and the Referee Box Receiver Thread. Moreover, theGame Thread includes some modules. They are described below.

Fig.8 Software architecture

4.1 Strategy system
Strategy system is improved from last year. The architecture of new strategy system is illustrated in Fig. 9. 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 command to kick a ball for the robot. Alternatively, the "Wall Defense
Action" means the robots move to the position defending the goal.

Fig.9 Construction of strategy system
4.2 Path Planning
Destination of each robot is determined by the Strategy system. Path Planning generates a route that avoids defense area and the other robots. The method of generatingroute is followings. First, it generates the linear route that connects the current position and destination. Next, it checks all of obstacle position. If there is obstacle on theroute already generated, it is changed the route using an arc formed with constantradius at around the obstacle. Then, if there is still other obstacle on the route, theradius is increased until that can be avoiding obstacle.

Fig.9 Route generation to avoid obstacle
4.3 Speed Controller
Speed Controller calculates the data related velocity to send the robot based on thegenerated route. Speed Controller has several types. Optimal type of the controller isselected corresponding to the role of robot.

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.