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The design and application of a robotic vacuum cleaner

Min-Chie Chiu 2

Department of Automatic Control Engineering

Chungchou Institute of Technology4

6, Lane 2, Sec. 3, Shanchiao Rd.

Yuanlin, Changhua 510036

Taiwan, R.O.C.

Long-Jyi Yeh8

Y. C. Lin

Department of Mechanical Engineering10

Tatung University

Taiwan, R.O.C12

Abstract

Robots are widely used in modern industrial manufacturing, in households, in14

entertainment, and in the security sector. To facilitate targeted functions, interactivity in

conjunction with high quality sensors play essential roles. In this paper, an intelligent and16

interactive robotic vacuum cleaner is developed. By using a wireless transport protocol

(802.11b), theuser canmonitor the robots path andremotelymanipulate itsmovements with18

a pc interface. Research has developed two kinds of functions an auto-vacuum-cleaning

mode and a remote-manipulating mode. For the auto-vacuum-cleaning mode, two path-20

searching algorithms are developed one is the right-side edge-searching and obstacle-

avoiding algorithm, the other is the S-type sweeping and obstacle-avoiding algorithm.22

Additionally, a system program for plotting the robots path is developed. By calculating

data submitted from a micro controller and an error compensator, the immediate path of a24

robot is shown on a pc monitor. Therefore, further path correction commands can be sent to

the robot by theremote-manipulatingmode in the main serverpc. Consequently, a prototype26

robot has been manufactured and tested in the laboratory.

Keywords and phrases : Edge-searching, infrared rays, robotic vacuum cleaner.28

E-mail: [email protected]

Journal of Information & Optimization Sciences

Vol. ( ), No. , pp. 124

c Taru Publications

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2 M. C. CHIU, L. J. YEH AND Y. C. LIN

1. Introduction

Robots have been used all over the world. A role for a new generation2

of robots is eagerly awaited. In order to improve society in general, new

types of robots are being introduced.4

As new trends in the modern world evolve, robots begin to make

their presence felt. Robotic vacuum cleaners [1], ladder-climbing robots6

[2], and robots for the blind [3], etc., have already been created. Currently,

various robotic vacuum cleaners have been presented; however, they have8

focused on ground cleaning and lack an interactivity between the robot

and the user. One such robot, roomba, created by iRobot for ground10

cleaning, cleans by expanding the vacuuming area with a screw path,

recodes the path coordinates, and then sweeps the non-cleaned area.12

Soon, though, the robots path is blocked and a new vacuuming area is

required, hence an interactive user becomes crucial. In order to improve14

interactivity between robot and user, an intelligent robot in conjunction

with a wireless internet has been developed.16

By using a wireless series transport model (802.11b), not only can

the vacuuming function be performed automatically, but the path can18

also be recorded and shown on the monitoring system; additionally, by

manipulating the moving command, the robot can efficiently clean up the20

entire area.

To reach our proposed goal, the selection of an appropriate high22

sensitivity sensor is essential. Versatile sensors such as a camera catch device

(CCD) [4, 5] used for path-guiding in an unknown environment have been24

addressed. Moreover, a moveable ultrasonic detector [6] used in avoidingobstacles is also discussed. Thus, a robotic vacuum cleaner equipped with26

an ultrasonic sensor and a wireless network is proposed.

2. System design28

2.1 Structure of the system

As indicated in Figure 1, two components in the system are recog-30

nized. one is the robot carrier and the other is the interface between the

robot and the user. The heart of the robot is a micro controller (Microchip32

PIC18F452) used for receiving a signal from a red ray instrument and

controlling DC motor through a DB300 driver (3MEN) and an angular34

feedback module. In addition, the data can be transmitted by a wireless

series transport module and monitoring computer system. The systems36

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DESIGN ROBOTIC VACUUM CLEANER 3

electric power is provided by 2 sets of Pb-made batteries (12V 5Ah,

YUASA) and one set of transformers. A pc-interface that is used to2

calculate and monitor data transmitted from a micro-controller can make

maps and submit commands.4

Figure 1

System structure6

2.2 Structure of robot

As indicated in Figure 2, the robot is 400 mm in diameter and 200 mm8

in height and weighs 1 0.5 kg. Several components two sets of 12-

voltage Pb-type batteries, two sets of DC motors and its drivers, one set10

of omni-rollers, one set of electric boards, and six sets of red radio sensor

and aluminum boards are included.12

Figure 2

Photo of the intelligent robot14

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Table 1

Specification of PIC18F452

Features PIC18F452

Operating frequency DC-40MHzProgram memory (Bytes) 32K

Program memory (Instructions) 16384

Data memory (Bytes) 1536

Data EEPROM memory (Bytes) 256

Interrupt sources 18

I/O Ports Ports A, B, C, D, E

Timers 4

Capture/Compare/PWM Modules 2

Serial communications MSSP addressable USART

Parallel communications PSP

10-bit Analog-to-Digital module 8 input channelsRESETS (and Delays) POR, BOR, RESET instruction, Stack full,

Stack underflow (PWRT, OST)

Programmable low voltage detect Yes

Programmable Brown-out reset Yes

2

As indicated in Figures 4 and 5, an AD inverter with six channels

(RA0RA3, RA5 and RE0), two PWN(RC1, RC2) outputs, two counters4

with pulse input (RA4, RC0), a motors start and stop, a clockwise/

counterclockwise rotation(RD0RD3), and a RS232 connector for receiv-6

ing and submitting purposes (RC6, RC7) are included in the controllers

circuit.8

Figure 4

Photo of micro-controller10

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Figure 5

The controllers circuit2

2.2.3 Power resource

As indicated in Figure 6, a DC motor (Japan servo-DME44S50G54A)4

with 12V 9.2 W66.6 rpm and a torque of 0.96 N.m is used. In conjunction

with the driver (3MEN-DB300) shown in Figure 7, the electronic brake6

with clockwise/counterclockwise and PWM speed control is used. Inorder to avoid the vibration effect during running, a spring shown in8

Figure 8 is added to the motors.

10

Figure 6

Photo of DC motor

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Figure 7

A view of the DC motors driver2

Figure 8

Vibration isolator4

2.2.4 Angle feedback module

As shown in Figure 9, the angular feedback module has been estab-6

lished by a photo interrupter and a 7414 Schmitt trigger inverter. A high

and low signal will feedback to adjust the speed and position of the motor8

while the photo splitter disk is running. A 60 pulse per cycle for the photo-

splitter disk is read. Resolution reaches 6 degrees per pulse.10

Figure 9

Angle feedback module12

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As shown in Figures 10 and 11, the 7414 inverter is used to depress

circuit noise.2

Figure 10

Photo of the photo interrupter4

Figure 11

Circuit diagram of the photo interrupter6

2.2.5 Infrared-ray-distance-detector

The appropriate selection of a distance detector regarded as the8

robots vision is an important issue. In our studies, the infrared-ray-

distance-detector (SHARP GP2D12) shown in Figure 12 is used.10

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Figure 12

Photo of GP2D122

The electric circuit diagram of GP2D12 is depicted in Figure 13.

4

Figure 13

Electric circuit diagram of GP2D12

In addition, the translation of analogue voltage to distance for GP2D126

is shown in Figure 14. As indicated in Figure 14, the available detecting

distance is 10cm80cm. The output is an analogue voltage. The charac-8

teristics of the infrared-ray-distance-detector include the following:

(1) Compact size.10

(2) Only 5 volts is required.

(3) Influence with respect to color reflection of the obstacle is low.12

(4) During precision detecting, there will be interference by outside

infrared rays.14

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Figure 14

The translation of analogue voltage to distance for GP2D122

2.2.6

Two kinds of MOXAs NPort W2150 wireless transport modules4

shown in Figure 15 are considered.

6

Figure 15

A NPort W2150

One is the infrastructure which can connect to the host by a wireless mode8

AP (access point). The other is the Ad-hoc mode shown in Figure 16.

The latter having a higher speed, is connected with two W2150s and is10

used here. By using IEEE802.11b transport protocol, the longest distance

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reached is 100 meters. Accordingly, the RS232 is composed of a one start

bit, 8 data bits, one end bit, and a baud rate of 9600 bps. At the beginning of2

the data record, one character will be added to ensure correctness during

data transmission; however, an error can occur. Therefore, the error will4

be detected by the software.

6

Figure 16

An ad-hoc mode

2.2.7 Interface between user and the robot8

This project is programmed by VISUALB ASIC(Version 6.0). By using

the pc interface, not only can the motion module be selected, but the path10

of the robot and related information can also be observed on the monitor

as shown in Figure 17. Moreover, the robot can be manipulated by the12

command submitted to the PC. The maximal allowable range of x and y

is 6m6m, where 15 twips represent one pixel.14

Figure 17

Interface of the PC16

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3. Path control and sketch and record for an automatic sweeping robot

3.1 Theoretical kinetic derivation2

The diameter of the robots wheel is 3 inches. The total pulse in a

photo splitter disk is 60. As shown in Figure 18, the distance between the4

wheels is 310 mm. The angle per pulse is small enough to be treated as an

isosceles triangle. Using an anti-triangular function, the angle can then6

be obtained as follows:

3 25.4 =239.39mm =240 mm (perimeter)8

L= 240 60 = 4 mm/pulse, where L is the moving distance per pulse

= 2 sin1(2/310) =0.74 , where is the angle per pulse10

Figure 18

Viewpoint of each pulse12

3.2 Right-side obstacle-avoiding during edge-searching

In an unknown environment, efficient edge-searching, obstacle-14

avoiding and vacuuming during the robotic operation is an essential issue.

A path-searching diagram is presented and shown in Figure 19.16

3.3 Edge-searching principle

When the robot is moving along a wall as shown in Figure 20, a fixed18

distance of R between the wall and the infrared rays is set. At that moment,

the speed of the left wheel is 50% and the speed of the right wheel is20

(50+ (R R) 1.2) %. By using the speed ratio of 1.2, edge-searching

can be determined.22

3.4 Obstacle-avoiding in front of the robot

Two kinds of obstacle-avoiding modules are used. If the obstacle at24

the front of the robot, at RF or LF, is within 10 cm as shown in Figure21 and

is detected, the robot will turn left 90 degrees and detect the distance R .26

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Figure 19

Flow diagram of right-side obstacle avoiding2

Figure 20

Moving along the wall4

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Figure 21

Obstacle in front of the robot2

Figure 22

Obstacle in front of the robot (case 1)4

If R is greater than 40 cm, the robot will move forward 20 cm and turn

right as shown in Figure 22; otherwise, the robot will keep edge-searching6

as shown in Figure 23.

8

Figure 23

Obstacle in front of the robot (case 2)

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3.7 S-type vacuuming and obstacle avoidance

The S-type vacuuming module in conjunction with obstacle avoiding2

is used during the robots running process. When an obstacle is met, the

x coordinates will be recorded and continue to move in a S-type pattern.4

The path-searching diagram is shown in Figure 26. Additionally, the path

layout is shown in Figure 27.6

Figure 26

Diagram of S-type vacuuming path8

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Figure 27

S-type vacuuming path2

4. Experiment

4.1 Experiment of automatic vacuuming for a robot4

In the experimental process, the obstacles are located at both the right

side and the middle region. As indicated in Figure 28, the robot started the6

ground vacuuming work along a S-type path.

8

(Contd. Figure 28)

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2

4

(Contd. Figure 28)

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2

4

(Contd. Figure 28)

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Figure 28

Photos of the vacuuming process of the automatic robot along a

S-type path (S1 to S22)

2

4.2 Path recording for a vacuuming robot

In our experiment, the PC server is 10 meters away from the robot. By4

using the wireless transmission between the user and the robot, not onlycan the location of robot be calculated, but a command can also be sent to6the robot. The path of the robot is therefore recorded and plotted in thePC server. As indicated in Figure 29, the robots path is plotted during the8vacuuming process.

10

(Contd. Figure 29)

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2

4

(Contd. Figure 29)

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2

4

(Contd. Figure 29)

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Figure 29

Photos of the path record for a ground vacuuming robot2

5. Results and discussions

By using the wireless transmission module in a series port (802.11b),4

the user can monitor the robots path and remotely manipulate the

movements of the robot with a pc interface.6

In order to move forward in an unknown environment during the

robots operation, signals submitted from three kinds of infrared-ray-8

distance-detectors at the right, the left, and the front sides are essential. By

calculating the data with a PIC18F452 micro controller, two DC motors10

can be controlled during edge-searching, obstacle-avoiding, and path-

searching. For the auto-vacuuming mode, two kinds of algorithms in12

path-searching are developed in this paper one is the right-side edge-

searching and obstacle-avoiding, the other is the S-type vacuuming and14obstacle-avoiding. A prototype robot has been manufactured and tested.

In addition, the system program for plotting the robots path has been16

developed. By calculating data submitted from a micro controller and an

error compensator, the immediate path of a running robot is shown on a18

pc monitor.

6. Conclusion20

In this paper, an interactive robot has been presented. The prelimi-

nary goals of our research (a vacuuming function, plotting and monitoring22

a path, and manipulation and control from a pc server) have been

achieved. Some aspects of our research which can be improved for an24

interactive robot are proposed below:

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(1) If there is an infrared light already in the environment, the infrared-

ray-distance-detector can be interfered with and errors might occur.2

To deal with this problem, an image guiding system in the robot is

suggested.4

(2) A rotating angle calculated by the angle feedback system is used in

this research. To increase its accuracy, an electrical compass with a6

feedback system is recommended.

As suggested in the first item (image guiding system), although the8

robot is sometimes not in the vacuuming mode, the image guiding system

can be used as a monitoring system which will provide a security function.10

References

[1] J. W. Lee, S. U. Choi, C. H. Lee, Y. J. Lee and K. S. Lee, A study12for AGV steering control and identification using vision system,Industrial Electronics, Vol. 3 (2001), pp. 12-16; pp. 15751578.14

[2] M. D. Mohsen and M. M. Majid, Stair Climber Smart Mobile Robot(MSRox), Tarbiat Modares, University of Iran, Iran Autonomous16Robots, Vol. 20 (2006), pp. 314.

[3] H. Mori, S. Kotani and N. Kiyohiro, A robotic travel aid HITOMI,18Proceedings of the IEEE/RJS/GI, International Conference on IntelligentRobot and Systems, Vol. 13 (1999), pp. 17161723.20

[4] Y. X. Chen,Design and Implementation of Car-Like Mobile Robot withIntelligent Parking Capability, Department of Electrical Engineering,22NCKU, ROC, 2002.

[5] Y. Ando and S. Yuta, Following a wall by an autonomous mobile24robot with a sonar-ring,IEEE International Conference on Robotics andAutomation, Vol. 4 (1995), pp. 25992606.26

[6] A. Louchene and N. E. Bouguechal, Indoor mobile robot local pathplanner with trajectory tracking, Journal of Intelligent and Robotic28Systems, Vol. 37 (2003), pp. 163175.

Received December, 2007; Revised April, 200830

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