The design and application of a robotic vacuum cleaner

Transcription

1 The design and application of a robotic vacuum cleaner 1 Min-Chie Chiu Department of Automatic Control Engineering Chungchou Institute of Technology, Lane, Sec. 3, Shanchiao Rd. Yuanlin, Changhua 503 Taiwan, R.O.C. Long-Jyi Yeh Y. C. Lin Department of Mechanical Engineering Tatung University Taiwan, R.O.C Abstract Robots are widely used in modern industrial manufacturing, in households, in 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 and interactive robotic vacuum cleaner is developed. By using a wireless transport protocol (0.11b), the user can monitor the robot s path and remotely manipulate its movements with 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 pathsearching algorithms are developed one is the right-side edge-searching and obstacleavoiding algorithm, the other is the S-type sweeping and obstacle-avoiding algorithm. Additionally, a system program for plotting the robot s path is developed. By calculating data submitted from a micro controller and an error compensator, the immediate path of a robot is shown on a pc monitor. Therefore, further path correction commands can be sent to the robot by the remote-manipulating mode in the main server pc. Consequently, a prototype robot has been manufactured and tested in the laboratory. Keywords and phrases : Edge-searching, infrared rays, robotic vacuum cleaner. minchie.chiu@msa.hinet.net Journal of Information & Optimization Sciences Vol. ( ), No., pp. 1 c Taru Publications

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 generation of robots is eagerly awaited. In order to improve society in general, new types of robots are being introduced. As new trends in the modern world evolve, robots begin to make their presence felt. Robotic vacuum cleaners [1], ladder-climbing robots [], and robots for the blind [3], etc., have already been created. Currently, various robotic vacuum cleaners have been presented; however, they have focused on ground cleaning and lack an interactivity between the robot and the user. One such robot, roomba, created by irobot for ground cleaning, cleans by expanding the vacuuming area with a screw path, recodes the path coordinates, and then sweeps the non-cleaned area. Soon, though, the robots path is blocked and a new vacuuming area is required, hence an interactive user becomes crucial. In order to improve interactivity between robot and user, an intelligent robot in conjunction with a wireless internet has been developed. By using a wireless series transport model (0.11b), not only can the vacuuming function be performed automatically, but the path can also be recorded and shown on the monitoring system; additionally, by manipulating the moving command, the robot can efficiently clean up the entire area. To reach our proposed goal, the selection of an appropriate high sensitivity sensor is essential. Versatile sensors such as a camera catch device (CCD) [, 5] used for path-guiding in an unknown environment have been addressed. Moreover, a moveable ultrasonic detector [] used in avoiding obstacles is also discussed. Thus, a robotic vacuum cleaner equipped with an ultrasonic sensor and a wireless network is proposed.. System design.1 Structure of the system As indicated in Figure 1, two components in the system are recognized. 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 (Microchip PIC1F5) used for receiving a signal from a red ray instrument and controlling DC motor through a DB300 driver (3MEN) and an angular feedback module. In addition, the data can be transmitted by a wireless series transport module and monitoring computer system. The system s

3 DESIGN ROBOTIC VACUUM CLEANER 3 electric power is provided by sets of Pb-made batteries (1V 5Ah, YUASA) and one set of transformers. A pc-interface that is used to calculate and monitor data transmitted from a micro-controller can make maps and submit commands. Figure 1 System structure. Structure of robot 1 As indicated in Figure, the robot is 00 mm in diameter and 00 mm in height and weighs kg. Several components two sets of 1- voltage Pb-type batteries, two sets of DC motors and its drivers, one set of omni-rollers, one set of electric boards, and six sets of red radio sensor and aluminum boards are included. 1 Figure Photo of the intelligent robot

4 M. C. CHIU, L. J. YEH AND Y. C. LIN..1 Design of the robot s base plate As indicated in Figure 3, the whole base plate is a circle. It has the advantage of uniform loading onto the rollers with a constant velocity. A mechanism designed for collecting the dust is created by a -degree collector and vacuum hole. Figure 3 The design drawing of the robot s base plate Electric circuit of the micro-controller As indicated in Table 1, PIC1F5, a micro-controller, has a working frequency of 0MHz. Two kinds of reset functions (power-on reset and brown-out reset), including a counter for power-up delay, a counter for oscil-power-up delay, and a dog-guard counter, are built in. The related memory with respect to the program, the data, and the EEPROM have 3000, 153, and 5 bytes. The program s memory is the Flash ROM, which can be written repeatedly. Its related module includes an 1 interrupter, a counter, a CCP modulus (capture, compare, and pulse width modulation), an AD (analog to digital) translator with ten bits and eight channels, and a 3 I/O-point. Additionally, it communicates with an USART and MSSP in a series port module as well as bits in a parallel port module.

5 DESIGN ROBOTIC VACUUM CLEANER 5 Table 1 Specification of PIC1F5 Features PIC1F5 Operating frequency DC-0MHz Program memory (Bytes) 3K Program memory (Instructions) 13 Data memory (Bytes) 153 Data EEPROM memory (Bytes) 5 Interrupt sources 1 I/O Ports Ports A, B, C, D, E Timers Capture/Compare/PWM Modules Serial communications MSSP addressable USART Parallel communications PSP -bit Analog-to-Digital module input channels RESETS (and Delays) POR, BOR, RESET instruction, Stack full, Stack underflow (PWRT, OST) Programmable low voltage detect Yes Programmable Brown-out reset Yes As indicated in Figures and 5, an AD inverter with six channels (RA0 RA3, RA5 and RE0), two PWN(RC1, RC) outputs, two counters with pulse input (RA, RC0), a motor s start and stop, a clockwise/ counterclockwise rotation(rd0 RD3), and a RS3 connector for receiving and submitting purposes (RC, RC7) are included in the controller s circuit. Figure Photo of micro-controller

6 M. C. CHIU, L. J. YEH AND Y. C. LIN..3 Power resource Figure 5 The controller s circuit As indicated in Figure, a DC motor (Japan servo-dmes50g5a) with 1V 9. W. rpm and a torque of 0.9 N.m is used. In conjunction with the driver (3MEN-DB300) shown in Figure 7, the electronic brake with clockwise/counterclockwise and PWM speed control is used. In order to avoid the vibration effect during running, a spring shown in Figure is added to the motors. Figure Photo of DC motor

7 DESIGN ROBOTIC VACUUM CLEANER 7 Figure 7 A view of the DC motor s driver Figure Vibration isolator.. Angle feedback module As shown in Figure 9, the angular feedback module has been established by a photo interrupter and a 71 Schmitt trigger inverter. A high and low signal will feedback to adjust the speed and position of the motor while the photo splitter disk is running. A 0 pulse per cycle for the photosplitter disk is read. Resolution reaches degrees per pulse. 1 Figure 9 Angle feedback module

8 M. C. CHIU, L. J. YEH AND Y. C. LIN As shown in Figures and 11, the 71 inverter is used to depress circuit noise. Figure Photo of the photo interrupter Figure 11 Circuit diagram of the photo interrupter..5 Infrared-ray-distance-detector The appropriate selection of a distance detector regarded as the robot s vision is an important issue. In our studies, the infrared-raydistance-detector (SHARP GPD1) shown in Figure 1 is used.

9 DESIGN ROBOTIC VACUUM CLEANER 9 Figure 1 Photo of GPD1 The electric circuit diagram of GPD1 is depicted in Figure Figure 13 Electric circuit diagram of GPD1 In addition, the translation of analogue voltage to distance for GPD1 is shown in Figure 1. As indicated in Figure 1, the available detecting distance is cm 0cm. The output is an analogue voltage. The characteristics of the infrared-ray-distance-detector include the following: (1) Compact size. () Only 5 volts is required. (3) Influence with respect to color reflection of the obstacle is low. () During precision detecting, there will be interference by outside infrared rays.

10 M. C. CHIU, L. J. YEH AND Y. C. LIN Figure 1 The translation of analogue voltage to distance for GPD1.. Two kinds of MOXA s NPort W150 wireless transport modules shown in Figure 15 are considered. Figure 15 A NPort W150 One is the infrastructure which can connect to the host by a wireless mode AP (access point). The other is the Ad-hoc mode shown in Figure 1. The latter having a higher speed, is connected with two W150s and is used here. By using IEEE0.11b transport protocol, the longest distance

11 DESIGN ROBOTIC VACUUM CLEANER 11 reached is 0 meters. Accordingly, the RS3 is composed of a one start bit, data bits, one end bit, and a baud rate of 900 bps. At the beginning of the data record, one character will be added to ensure correctness during data transmission; however, an error can occur. Therefore, the error will be detected by the software. 1 1 Figure 1 An ad-hoc mode..7 Interface between user and the robot This project is programmed by VISUAL BASIC (Version.0). By using the pc interface, not only can the motion module be selected, but the path 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 the command submitted to the PC. The maximal allowable range of x and y is m m, where 15 twips represent one pixel. 1 Figure 17 Interface of the PC

12 1 M. C. CHIU, L. J. YEH AND Y. C. LIN 3. Path control and sketch and record for an automatic sweeping robot 3.1 Theoretical kinetic derivation The diameter of the robot s wheel is 3 inches. The total pulse in a photo splitter disk is 0. As shown in Figure 1, the distance between the wheels is 3 mm. The angle per pulse is small enough to be treated as an isosceles triangle. Using an anti-triangular function, the angle θ can then be obtained as follows: 3 5. π = mm = 0 mm (perimeter) L = 0 0 = mm/pulse, where L is the moving distance per pulse θ = sin 1 (/3) = 0.7, where θ is the angle per pulse 1 Figure 1 Viewpoint of each pulse 3. Right-side obstacle-avoiding during edge-searching 1 1 In an unknown environment, efficient edge-searching, obstacleavoiding and vacuuming during the robotic operation is an essential issue. A path-searching diagram is presented and shown in Figure Edge-searching principle 1 0 When the robot is moving along a wall as shown in Figure 0, a fixed 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 is (50 + (R R) 1.) %. By using the speed ratio of 1., edge-searching can be determined. 3. Obstacle-avoiding in front of the robot Two kinds of obstacle-avoiding modules are used. If the obstacle at the front of the robot, at RF or LF, is within cm as shown in Figure 1 and is detected, the robot will turn left 90 degrees and detect the distance R.

13 DESIGN ROBOTIC VACUUM CLEANER 13 Figure 19 Flow diagram of right-side obstacle avoiding Figure 0 Moving along the wall

14 1 M. C. CHIU, L. J. YEH AND Y. C. LIN Figure 1 Obstacle in front of the robot Figure Obstacle in front of the robot (case 1) If R is greater than 0 cm, the robot will move forward 0 cm and turn right as shown in Figure ; otherwise, the robot will keep edge-searching as shown in Figure 3. Figure 3 Obstacle in front of the robot (case )

15 DESIGN ROBOTIC VACUUM CLEANER Right side without obstacle During the side-searching process, if the distance R at right-side sensor is greater than 0 cm, the right-side obstacle-avoiding module will start up, move forward for 30 cm, turn right 90 degrees, move forward for 0 cm, and keep edge-searching as shown in Figure. 1 Figure Without an obstacle at the right side 3. Keeping aliment between carrier and wall By using the data difference between the two sensors, the small angle control for the right-side motor can be operated till the deviation is less than. In that case, the aliment between the carrier and wall as shown in Figure 5 is assumed to be reached. 1 Figure 5 Carrier Aligned with a Wall

16 1 M. C. CHIU, L. J. YEH AND Y. C. LIN 3.7 S-type vacuuming and obstacle avoidance The S-type vacuuming module in conjunction with obstacle avoiding is used during the robot s running process. When an obstacle is met, the x coordinates will be recorded and continue to move in a S-type pattern. The path-searching diagram is shown in Figure. Additionally, the path layout is shown in Figure 7. Figure Diagram of S-type vacuuming path

17 DESIGN ROBOTIC VACUUM CLEANER 17 Figure 7 S-type vacuuming path. Experiment.1 Experiment of automatic vacuuming for a robot In the experimental process, the obstacles are located at both the right side and the middle region. As indicated in Figure, the robot started the ground vacuuming work along a S-type path. (Contd. Figure )

18 1 M. C. CHIU, L. J. YEH AND Y. C. LIN (Contd. Figure )

19 DESIGN ROBOTIC VACUUM CLEANER 19 (Contd. Figure )

20 0 M. C. CHIU, L. J. YEH AND Y. C. LIN Figure Photos of the vacuuming process of the automatic robot along a S-type path (S1 to S). Path recording for a vacuuming robot In our experiment, the PC server is meters away from the robot. By using the wireless transmission between the user and the robot, not only can the location of robot be calculated, but a command can also be sent to the robot. The path of the robot is therefore recorded and plotted in the PC server. As indicated in Figure 9, the robot s path is plotted during the vacuuming process. (Contd. Figure 9)

21 DESIGN ROBOTIC VACUUM CLEANER 1 (Contd. Figure 9)

22 M. C. CHIU, L. J. YEH AND Y. C. LIN (Contd. Figure 9)

23 DESIGN ROBOTIC VACUUM CLEANER 3 Figure 9 Photos of the path record for a ground vacuuming robot 5. Results and discussions By using the wireless transmission module in a series port (0.11b), the user can monitor the robot s path and remotely manipulate the movements of the robot with a pc interface. In order to move forward in an unknown environment during the robot s operation, signals submitted from three kinds of infrared-raydistance-detectors at the right, the left, and the front sides are essential. By calculating the data with a PIC1F5 micro controller, two DC motors can be controlled during edge-searching, obstacle-avoiding, and pathsearching. For the auto-vacuuming mode, two kinds of algorithms in path-searching are developed in this paper one is the right-side edgesearching and obstacle-avoiding, the other is the S-type vacuuming and obstacle-avoiding. A prototype robot has been manufactured and tested. In addition, the system program for plotting the robot s path has been developed. By calculating data submitted from a micro controller and an error compensator, the immediate path of a running robot is shown on a pc monitor.. Conclusion In this paper, an interactive robot has been presented. The preliminary goals of our research (a vacuuming function, plotting and monitoring a path, and manipulation and control from a pc server) have been achieved. Some aspects of our research which can be improved for an interactive robot are proposed below:

24 M. C. CHIU, L. J. YEH AND Y. C. LIN (1) If there is an infrared light already in the environment, the infraredray-distance-detector can be interfered with and errors might occur. To deal with this problem, an image guiding system in the robot is suggested. () A rotating angle calculated by the angle feedback system is used in this research. To increase its accuracy, an electrical compass with a feedback system is recommended. As suggested in the first item (image guiding system), although the 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. References [1] J. W. Lee, S. U. Choi, C. H. Lee, Y. J. Lee and K. S. Lee, A study for AGV steering control and identification using vision system, Industrial Electronics, Vol. 3 (001), pp. 1-1; pp [] M. D. Mohsen and M. M. Majid, Stair Climber Smart Mobile Robot (MSRox), Tarbiat Modares, University of Iran, Iran Autonomous Robots, Vol. 0 (00), pp [3] H. Mori, S. Kotani and N. Kiyohiro, A robotic travel aid HITOMI, Proceedings of the IEEE/RJS/GI, International Conference on Intelligent Robot and Systems, Vol. 13 (1999), pp [] Y. X. Chen, Design and Implementation of Car-Like Mobile Robot with Intelligent Parking Capability, Department of Electrical Engineering, NCKU, ROC, 00. [5] Y. Ando and S. Yuta, Following a wall by an autonomous mobile robot with a sonar-ring, IEEE International Conference on Robotics and Automation, Vol. (1995), pp [] A. Louchene and N. E. Bouguechal, Indoor mobile robot local path planner with trajectory tracking, Journal of Intelligent and Robotic Systems, Vol. 37 (003), pp Received December, 007; Revised April, 00