Apparatus and method for measuring position of mobile robot

#This application claims the benefit of Korean Application No. 2002-19039, filed Apr. 8, 2002, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.

#1. Field of the Invention

#The present invention relates generally to measurement of a position of a robot, and more particularly, to an apparatus and method to measure a position of a mobile robot working while moving on a plane.

#The above and other objects and advantages of the invention will become apparent and more appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which:

#FIG. 1 is a view showing a conventional system to measure a position of a mobile robot using image information of a work area and traveling information of the mobile robot;

#FIGS. 2A and 2B are side and plan views of a conventional system to measure a position of a mobile robot using pseudo satellites and a GPS receiver;

#Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

#FIG. 3A is a block diagram of an apparatus to measure a position of a mobile robot according to an embodiment of the present invention. As shown in FIG. 3A, a mobile robot 302 includes a control unit 306 and an RF reader 308. The control unit 306 controls all operations of the mobile robot 302. The RF reader 308 generates an RF signal, and receives and demodulates an RF signal generated by the RF tag 304. The RF tag 304, which is a sensor cell, is assigned and stores a unique number. When the RF reader 308 generates an RF signal, the RF tag 304 uses the generated RF signal as power, and provides the stored unique number to the RF reader 308.

#FIG. 3B is a circuit diagram showing the construction of the RF tag 304 of the mobile robot position measurement apparatus shown in FIG. 3A. As shown in FIG. 3B, the RF tag 304 is realized in a passive manner which does not require additional power, and uses the RF signal generated by the RF reader 308 as power. The RF tag 304 includes a resonance circuit having an inductor L1, a capacitor C1, a resistor R1, and a microchip 354. The microchip 354 has a rectifying device, a fundamental RF modulating device and a non-volatile memory formed therein (internal construction of the microchip 354 is not shown). The inductor L1 operates as an antenna to transmit/receive an RF signal. When the RF signal generated by the RF reader 308 of the mobile robot 302 is received, an alternating current (AC) voltage is induced in the inductor L1. This AC voltage is converted into a direct current (DC) voltage by the rectifying device of the microchip 354, thus enabling the capacitor C1 to be charged by the DC voltage. The RF tag 304 uses a charged voltage of the capacitor C1 as power. The non-volatile memory within the microchip 354 is used to store position information on an installation position of the RF tag 304. In this case, an electrical erasable and programmable read only memory (EEPROM) enabling both reading and writing of data, or an electrical programmable read only memory (EPROM) enabling only reading of data is employed as the non-volatile memory. The EEPROM enables both writing and reading of data, so the position information of the RF tag 304 may be freely changed if necessary. Therefore, the EEPROM provides great flexibility in utilizing the position measurement apparatus of the present invention. On the other hand, while the EPROM enables only reading of a previously stored unique number, it is inexpensive relative to the EEPROM, thereby reducing installation cost and maintenance cost of the mobile robot position measurement apparatus.