KIKS 2013 Extended Team Description
Ryu Goto, Takaya Asakura, Naomichi Fujii, Kosuke Matsuoka, Masataka Mizuno,
Tetsuya Sano, Yuya Onuma, Hiroshi Nagata, 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/~sugi/RoboCup.html

Abstract This paper presents a detailed description of KIKS in addition to theteam description paper of small size league in RoboCup 2013. Our robots and systems are designed under the SSL 2013 rules in order to participate in the RoboCupcompetition. The major improvements in this year are the enhancement of the performance and robustness of wheels, electrical circuit and automatic control system.
The overviews of them are described
Keywords: RoboCup, small-size league, engineering education, global vision

1. Introduction
In RoboCup world competition, our team has continuously participated since 2004.
We came in top 4 in Singapore, Istanbul and in top 3 in Mexico last year. Since weare aiming for higher place compared with last year, further improvements have been
done in this year.
One of the educations for creative minds of students is using the robot contest. We
have executed the robot contest in our college just like RoboCup junior every year. So,
main purpose of our participation to the RoboCup world competition is confirmationand evaluation of effect for creativity.
In last year, there was a problem that the travelling performance of robots was poor.
So, we redesigned a new wheel and improved the stability of the robots under travelling on the field. We also redesigned speed controller on the AI server. As the results,response performance was better than that of last year.
The main topics of robot’s hardware developed for 2013 model are following terms,
・Improvement of the wheels
・Improvement of the electric circuit
・Improvement of the speed controller on the AI systemadfa, p. 1, 2012.
© Springer-Verlag Berlin Heidelberg 2012

2. Hardware of the robot
In 2013 model, we redesigned focusing on the following points.
1. Lighter body
2. Lower center of gravity
3. Improvement of layout of wheels
4. Simpler mechanism and maintenance
The new robot is shown in Fig. 1 with previous robot. The specification of a robot
is summarized in Table 1.

Fig. 1 Comparison between New model (right side) and previous model
Table 1 Specification of a robot
weight2012version

2013version

2.4kg

1.9kg

Main material

Aluminum alloy

Driving motor

maxon EC45flat(30watt)

Gear ratio

3.6:1

4.0:1

Wheel diameter

56mm

50mm

Number of solenoids

Straight kick:1(round)
Chip kick:2(round)

Straight kick:1(flat)
Chip kick:1(flat)

Ball speed of 8m/s

Straight kick power
Chip kick power(max 10m/s)(max 9m/s)

3.0m away from robot with initial angle of 40°

adfa, p. 2, 2012.
© Springer-Verlag Berlin Heidelberg 2012

2.1. About the lighter body
For the reduction of weight, Aluminum thicknesses of each part are reduced asshown in Table 2. The method to fix the motor-block and the motor-shaft for 2013
model are shown in right side of Fig. 2 and Fig. 3, respectively.

Table 2 Thickness of each part2012 model2013 model

Chassis

5mm

3mm

Motor-block

10mm

3mm

2012 model2013 modelFig. 2 Improvement of method to fix motor-block on the body. Left one
shows the previous model.

2012 model2013 modelFig. 3 Improvement of method to fix motor-shaft on the block. Left one
shows the previous model.
adfa, p. 3, 2012.
© Springer-Verlag Berlin Heidelberg 2012

2.2. About the lower center of gravity
To decrease the center of gravity of robot, we improved by using the shorter diameter wheels and flatten solenoid.
2.2.1. Improvement of wheel
Since 2011 competition, we have used the same brushless motors as many teams
do. But, there was a problem in previous wheel for performance of straight-runningstability of the robot. That is, our robots were not able to run straight stably under thecondition of max speed of 2ms-1 and acceleration of 3ms-2. Figure 2(a) shows theprevious wheel. There were two reasons why straight-running stability was bad. One
was that the small tires on wheel do not rotate smoothly. There were frictions between
small tire and the tire’s house. Another one was that the characteristic of friction to
the playing field for rubber small tire is not so good. It is made to occur the slippingof robot in play, because of use of O-rings with cross-section of circle with smaller
ground contact area. Thus, we redesigned new wheel to solve these problems. It waschanged to new design for the small tire as shown in Fig. 4(b).

(a) Previous model’s wheel(b) 2012 model’s wheel
Fig. 4 Previous wheel and new wheel
The new small tire is constructed with wider urethane material, metal pin andwashers as shown in Fig. 5(b). A previous wire shaft connected with all small one ischanged into each metal pin in new wheel. By using of two washers in small wheel’s
house the friction of small tire is decreased drastically. The urethane tire with crosssection of rectangular is effective to enhance the friction between wheel and playing
field. In addition, since that tire is able to buy easily without special treatment, wecould get the time to develop and manufacture other equipment.
As the results of wider width of small tire and more precise approximate circumference in new wheel, the robot can run smoothly and turn quickly. In addition, the resinmaterial as outside shell for wheel is easy for cutting work, and is effective for realization of high-speed rotation due to its light weight.

adfa, p. 4, 2012.
© Springer-Verlag Berlin Heidelberg 2012

urethane material
O-ringwashersmall pin(a)Previous small tire(b) Present small tire
Fig. 5 Component of small tire on wheel
Whole image of wheel is shown in Fig. 6. Because of an axle is only put on theback-board in new wheel, it was decreased the position gap of axle hole between thefront- and back-board. In addition, it is easy for assembling and maintenance by attaching the axle of every small tire on wheel independently.

wire-shaft(a)Previous model’s wheel

pin-shaft(b) 2012 model’s wheel
Fig. 6 Whole image of wheel

2.2.2. Shorter radius of wheel
In fact of RoboCup 2012, it was used the wheel as shown in Fig. 7. That is, thenumber of small tire is decreased to 20 from 24 and the front plate was changed fromresin to duralumin in order to enhance the strength of the wheel itself. In addition, thematerial of the small tire was changed to MC nylon from polycarbonate. The performance of 2012 model was better than that of previous one. But it remains some problems. One of the important points is wheel size. It is too long because it designed to fit
the shaft of previous wheel. Another one is too bad for the precision of the shaft itself.
adfa, p. 5, 2012.
© Springer-Verlag Berlin Heidelberg 2012

So, in 2013model, it is short for the diameter of wheel from 56mm to 50mm. It iseffective for lower center of gravity, lighter weight and decreasing of the wheel’smoment of inertia. Simultaneously, the number of small tires is decreased to 16 from20. The photo image of new wheel is compared with that of 2012 model as shown inFig. 8.

back side

20 teeth

24 teethFig. 7 Wheel actually used in RoboCup 2012 (right one). Left one with 24
small tires is for the test.

Fig. 8 New wheel with 16 small tires for 2013 model (right side)

2.2.3. Flattened solenoid

Fig. 9 Flattened solenoid

adfa, p. 6, 2012.
© Springer-Verlag Berlin Heidelberg 2012

We have used conventional round-shaped solenoids until 2012. In 2013, we developed flatten solenoids. Its performance is same as the previous one. The image of newsolenoid is shown in Fig. 9. We could use same parts for both solenoids of chip kickand straight kick. Moreover, the top of motor is mostly located above on the metalplate. As the results, the height of robot and position of battery, that is, the center ofgravity is lower than 2012 model as shown in Fig. 10.
(a)(b)

Fig. 10 (a)Lower height of new robot (right one; red circle shows the battery,left one is previous model) and (b)top of the motor for driving wheel.
2.3 Improvement of wheels-layout
We improved the configuration of four driving wheels as shown in Fig. 11 by decreasing of the diameter of wheel. By placing all the wheels 45 degrees, the runningspeed of robot for omni-direction was made mostly equal and the easy control wasachieved.

Fig. 11 Configuration of four driving wheels (right one is for 2013 model)

adfa, p. 7, 2012.
© Springer-Verlag Berlin Heidelberg 2012

2.4 Simplification for mechanism and manufacturing
It is important to make robot easily because we have no enough members and time
to develop and manufacture. The rotation-bar of dribbling device of 2012 model was
movable for up- and down-ward, but in 2013 robots it was fixed as shown in Fig. 12.
Thus, we could realize easily making and decreasing of trouble. Furthermore, thenumber of parts is decreased, and a lot of ready-made parts are used.

Fig. 12 New dribbling device in 2013 model (right side)adfa, p. 8, 2012.
© Springer-Verlag Berlin Heidelberg 2012

3.

Electrical design

In this year, we have redesigned our electrical circuits. First, we introduced theFPGA board (Xilinx XC6SLX9). FPGA circuit controls all five motors mounted in arobot. That makes it possible to reduce the size of electronic circuit. Second, we replaced the previous discrete driver circuit with the IC (TI DRV8332) for motor-drivercircuit. This integrated motor-driver chip has three half bridges and gate drivers, anover-current protection and an over-temperature protection. It is expected that theelectric trouble will be decrease for the motor driver circuit. Figure13 shows the block
diagram of electronic circuit.

Fig. 13 Block diagram of electronic circuit

3.1 Motor Driver
Five motor-driver ICs (DRV8332) are mounted on the main board. Four of them
are for the travelling wheels and one is for the dribbling device. The current for eachfour travelling-wheels is monitored by two IC (TI INA213), and is used for current
restriction. Each motor has hall sensor, and each wheel's motor has an optical encoder(E4P). These signals connected all to the FPGA. The openMSP430 core of 16bit processor (running at 45MHz) calculates the control parameters based on above signals
by period with 2ms in FPGA board.

adfa, p. 9, 2012.
© Springer-Verlag Berlin Heidelberg 2012

3.2 Kicker
Our robots have two capacitors (each 250V 1500uF) connected at parallel. They arecharged up to 240V by boost converter of DC circuit. Two solenoids for straight-kickand chip-kick are operated by two IGBT devices. For charging to the battery and thecontrol of kicking device, they are performed by a micro-computer (AtmelATXMEGA32A4U). The UART is used for the communication between kicking- andmain-board with speed of 250kbaud.

3.3 Ball detector
The ball is detected by a photo interrupter. The driver (Hamamatsu PhotonicsS6809) output the signal whether a ball is in front of the robot by using IR LED.

3.4 Microcontroller
We chose an ATMEL AT32UC3B0512 microcontroller as main CPU. It controls thepower management of circuit, wireless communication, communication to the FPGA
and the kicker board etc., and runs at 60MHz. The firmware was developed to checkfor the circuit and to communicate to PC through by USB port.

adfa, p. 10, 2012.
© Springer-Verlag Berlin Heidelberg 2012

4.

Software design
4.1. Improvement of Speed Controller

In TDP of this year, we reported improvement of robot’s velocity controller. Thecontroller change the degree of decreasing velocity by using internal coefficient,however, it was not able to slow down with the speed taking into account maximum
acceleration. Now, we can do that by improving of the function for internal sliding
mode controller.
4.2. Previous Controller on TDP

Unit 1
Targetposition P*Sliding
modecontrol

Unit 2

1

Targetvelocity V*

PD


a* 𝑠

Present
position P
for robot

PID

Manipulated
 value

Present
velocity Vfor robot

Target velocity V*(mm/s)

Fig.14 New speed controller with two units
2000
18001600
140012001000
800600400
2000-200 0(H=2,amax=3700)(H=3,amax=3700)

0.51Time(s)1.5

Fig.15 H dependence of Target velocity V*adfa, p. 11, 2012.
© Springer-Verlag Berlin Heidelberg 20122New controller has 2 units as shown in Fig.14. The Unit 1 outputs the ideal motion
speed based on the robot’s position with considering of max acceleration andconvergence velocity V* to the target position P*. We applied tentatively sliding
mode control theory for speed of robot. As the result, it can easily control them. Theequation of sliding mode parameter σ and ideal acceleration 𝑎∗ are shown as follows,σ = H(𝑃∗ − 𝑃) + 𝑉 ∗(1a) ,1 (𝑥 > 0)𝑠𝑖𝑔𝑛(𝑥) = {(1b) ,−1 ( 𝑥 < 0)𝑎∗ = 𝑎𝑚𝑎𝑥 𝑠𝑖𝑔𝑛(𝜎)(1c) ,, where H is positive efficiency and used to decide convergence velocity.
The Unit 2 outputs the manipulated value to follow the robot’s velocity V to target
velocity V* getting from Unit 1. Since it has two-degree- of freedom control as shownin Fig.14, it is robust against the disturbance. Fig.15 shows the dependence of target
velocity for parameter H. It is shown that the target velocity V* is varied dependingon the coefficient H of eq.(1a). Especially in the case of H=3, it is shown that thetarget velocity V* is decreased linearly from the point of slow down. It means that theprecipitous change in velocity does not achieve actually. Thus, it is important tochoose appropriate parameter to get optimum performance under the condition of
stable control loop by applying.
3000
2500

Velocity(mm/s)

Robot's velocity V(mm/s)
2000
Target velocity V*(mm/s)
1500
1000
50000123time(s)Fig.16 Time dependence of velocity for robot

The time dependence of the velocity until arriving to the target position is shown in
Fig.16. It is shown that the agreement between robot's velocity and target velocity isfairly good. That is, it is found that the velocity of robot will be able to respond within
100msec.

adfa, p. 12, 2012.
© Springer-Verlag Berlin Heidelberg 2012

4.3. New Controller with changeable coefficient
As mentioned above, in new Controller, it is caused an overshoot for target velocity V* as increasing of parameter H, as shown in Fig. 17.
2500
Target velocity V*(mm/s)

2000(H=4,amax=3700)

1500(H=6,amax=3700)

1000
500
0-500

overshoot
-1000
00.5

1Time(s)1.52Fig. 17 Overshoot of target velocity depending on the parameter HThus, we try to use the following equation to solve this problem.
𝑠𝑖𝑔𝑛(𝑉 ∗ )(𝑃 ∗ − 𝑃 + 𝑠𝑖𝑔𝑛(𝑉 ∗ )𝑃𝑏𝑖𝑎𝑠 ) +(𝑉 ∗ )2 (𝐻𝑉 ∗ > 𝑎𝑚𝑎𝑥 )2𝑎𝑚𝑎𝑥
σ={(𝐻𝑉 ∗ < 𝑎𝑚𝑎𝑥 )𝐻(𝑃 ∗ − 𝑃) + 𝑉 ∗(2)This function performs the slowdown of target velocity with constant of acceleration amax and traces that appropriately on the sliding mode. Pbias is the constant andused to adjust the region for connecting two functions. As the results, we obtained theperformance shown in Fig. 18(a) and (b). In figures, it is same value for the parameter
H and amax in Fig. 17. It is found that even if H is big value, the robot can respond totarget velocity and the position without remarkable overshoot. Now, we can control
the velocity of robot properly if Unit2 in Fig.14 will be able to respond sufficiently.

adfa, p. 13, 2012.
© Springer-Verlag Berlin Heidelberg 2012

2000

Target velocity V*(mm/s)

(a)
1500
(H=4,amax=3700,Pbias=200)(H=6,amax=3700,Pbias=90)
1000

500

000.5-500

11.5

2Time(s)

1100
1000
900
800
700
600
500
400
300
200
100
0-100

Position error(mm)(b)(H=4,amax=3700,Pbias=200)(H=6,amax=3700,Pbias=90)

00.5

1Time(s)1.5

2Fig. 18 Time dependence of velocity (a) and position error (b) for robot

5. Conclusions
Our robots have been continuously improved in every year. As the results, thetravelling performance is getting better and robots are able to move more quickly thanlast year.
We hope that our robots will perform better in this coming competition.

adfa, p. 14, 2012.
© Springer-Verlag Berlin Heidelberg 2012