Abstract:
A device for retrieving data from radio frequency identification (RFID) tags is disclosed. The device includes a mobile base, a robotic arm, and a data reading device. The robotic arm is attached to the mobile base. The data reading device employed to collect the data of electric tags is attached to the end of the robotic arm. A device for retrieving data from an RFID tag arrives at the position, where the electric tag is, by moving the mobile base and adjusting the height of the robotic arm. The movement is controlled according to the position and the height of the electric tag. Finally, the data reading device reads the data stored in the electric tag.

Description:
RELATED APPLICATIONS 
     This application claims priority to Taiwan Application Serial Number 96211789, filed Jul. 19, 2007, which is herein incorporated by reference. 
     BACKGROUND 
     1. Field of Invention 
     The present invention relates to a mobile device having a robotic arm. More particularly, the present invention relates to a device with a robotic arm to retrieve data from radio frequency identification (RFID) tags. 
     2. Description of Related Art 
     A radio frequency identification (RFID) system is an automatic identification system, which relies on radio waves to store and retrieve data remotely. Generally speaking, the RFID system contains an RFID tag (i.e. an electronic tag) and a reader. The RFID tag is an object that can be applied to or incorporated into a product, the body of an animal, or the body of a human for the purposes of identification using radio waves to communicate between the tag and the reader. 
     Most electronic tags contain at least two parts. One is an integrated circuit for storing and processing information, modulating and demodulating an (RF) signal, and can also be used for other specialized functions. The second is an antenna for receiving and transmitting the signal. 
     RFID tags are divided into two general varieties: passive or active. Passive tags require no internal power supply. They are worked or operated only when a reader is nearby to power them. Passive tags have an operational reading distance ranging from about 10 cm up to a few meters relative to the reader, depending on the chosen radio frequency and antenna design/size. 
     Active tags require a power source, usually a small battery. Many active tags today have an operational reading range of hundreds of meters. Active tags typically have much longer distance range (approximately 500 m) than passive tags. However, passive tags are extensively applied to a variety of occasions because of their lower cost. Moreover, a fixed reader could retrieve data of passive tags within the operational reading distances range. However, if many fixed readers are installed to cover the whole range the cost increases. 
     The operational reading distances of RFID tags are limited by surrounding metal interference and communicational direction limitation so the effective operational reading distance is smaller than the distance in theory, which increases the difficulty to retrieve data. 
     The purpose of the RFID system is to provide a periodical check of goods, for example to take inventory of goods in a warehouse. In addition to wasting time, manually retrieving RFID data also misses tags easily. Moreover, if the RFID tags are installed too high or too low, the difficulty of retrieving data is increased. The risk will be increased when some goods with RFID tags are placed in dangerous areas (such as high temperature, radiation and so on), 
     SUMMARY 
     An object of the present invention is to provide a device for retrieving data from RFID tags to overcome the problem of manually retrieving RFID data. 
     In accordance with the foregoing and other objectives, the present invention provides the device for retrieving data from RFID tags. The device includes a mobile base, a robotic arm and a data reading device. 
     The device moves to the position of the RFID tags automatically using a mobile base and adjusts to the height of RFID tags with a robotic arm according to where the RFID tags are. The movement depends on the position and the height of the RFID tags. Finally, the reading device retrieves the data stored in the RFID tags. 
     According to an embodiment of the present invention, the mobile base includes a rotating platform, which could rotate 360 degrees. The mobile base could be a programmable mobile device comprising a microcomputer device, an electrical energy storage device and a driving device. The microcomputer device controls the programmable mobile device, the rotating platform, the robotic arm and the data reading device to work. The electrical energy storage device is connected to the programmable mobile device, the robotic arm device and the data reading device electrically and provides them power. The driving device includes a first driving motor and a second driving motor, which outputs—power through a transmission mechanism. 
     The robotic arm includes a mounting base and an arm device. The mounting base is mounted on the mobile base. The arm device is engaged with the mounting base and is driven by a first rotating device to adjust the height of the robotic arm. The arm device also includes a second rotating device. 
     The data reading device is set on the second rotating device of the arm device. The second rotating device adjusts the angle of the reading device to gain stronger signal strength when the reading device is retrieving data from RFID tags. 
     According to the aforementioned devices and embodiments, the present invention has advantages as follows. 
     1. Only one handheld reader is needed, and therefore prevents setting too many fixed readers. It could reduce the cost of building equipment and increase the read distance range especially for large-scale operational areas. 
     2. The device is set to work automatically so it could work after everyone has gone home after work and hence save the time and cost of retrieving data using manpower. 
     3. The device does not lose any RFID tags wherever the position and the height of RFID tags may be. When RFID tags cannot be retrieved data and show errors occur and the device could send messages to the management system. An administrator&#39;s responses will depend on the situation. 
     4. The device could work in dangerous areas such as high-temperature, explosion, radiation, collapse, high-altitude operation, fall and so on to prevent accidents. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where: 
         FIG. 1  is a schematic side view of an embodiment of a device for retrieving data from RFID tags in accordance with the present invention; 
         FIG. 2  is a perspective view of a mobile base in  FIG. 1 ; 
         FIG. 3  is a schematic side view of a robotic arm in  FIG. 1 ; 
         FIG. 4  is a sectional view of one of arm device in  FIG. 3 ; and 
         FIG. 5  is a schematic side view illustrating the movement of an embodiment of a device for retrieving data from RFID tags in accordance with the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
     Refer to  FIG. 1 . A device for retrieving data from radio frequency identification (RFID) tags  100  includes a mobile base  200 , a robotic arm  300  and a data-reading device  400 . The mobile base  200  includes a rotating platform  150  which could rotate 360 degrees. The robotic arm  300  is securely attached to the rotating platform  150  and is pivotally connected to the mobile base  200  through a shaft member. The data reading device  400  is attached to one end of the robotic arm  300  to retrieve data from RFID tags. 
     Refer to  FIG. 2 . In the present embodiment, a programmable mobile device is used to be an exemplary embodiment of the mobile base  200 , and is explained below. The programmable mobile device  20  includes an electrical energy storage device  201 , a microcomputer device  202  and a driving device  203 . 
     The electrical energy storage device  201  provides power for the device  100  and all electrical devices thereof. The microcomputer device  202  controls the various components comprising the mobile base  200  and the robotic arm  300 . The microcomputer device  202  functions depending on the written program. The driving device  203  includes a first driving motor  210  and a second driving motor  220  depending on the output signals from the microcomputer device  202  to work. 
     Refer to  FIG. 1  and  FIG. 2 . The programmable mobile device  20  could move on a track system or on a supporting surface. The programmable mobile is device  20  could be an automatic vehicle or an anthropomorphous machine (so-called robot). The device  100  is controlled by a program built in the programmable mobile device  20 , i.e. moving, rotation, height control and so on. A wired control or a remote control can also control the device  100 . The data reading device  400  is a reader which transmits power and signals to RFID tags by radiowave. 
     According to an embodiment of the present invention, the electrical energy storage device  201  includes a charge device and a battery. The charge device is connected to a power source (like AC 110V or 220V) and transfers the power source from alternating current into direct current. The charge device charges the battery or transmits the power source to the device  100  directly. The microcomputer device  202  is programmable with computer program language such as C language or C++ object-oriented programming language. The first driving motor  210  and the second driving motor  220  are DC servo motors, and drive wheels through transmission mechanisms  211 ,  221  separately. 
     After the driving device  203  receives the control signals from the microcomputer device  202 , the driving device  203  transforms the control signals into a driving signal through a driving circuit (not shown in the  FIG. 2 ). The first driving motor  210  and the second driving motor  220  are controlled by the driving signal separately so that the programmable mobile device  20  could move forward, back, right and left. 
     In an embodiment of the present invention, the programmable mobile device  20  moves forward on the supporting surface through the first driving motor  210  and the second driving motor  220  rotating forward at the same time. The programmable mobile device  20  moves back on the supporting surface through the first driving motor  210  and the second driving motor  220  rotating reverse at the same time. 
     The programmable mobile device  20  turns right on the supporting surface through the first driving motor  210  rotating forward and the second driving motor  220  rotating reverse at the same time. The programmable mobile device  20  turns left on the supporting surface through the first driving motor  210  rotating reverse and the second driving motor  220  rotating forward at the same time. 
     In  FIG. 3 , the robotic arm  300  includes a mounting base  310  and an arm device  320 . The arm device  320  is pivotally mounted on the mounting base  310  and has a plurality of telescopic devices  321 ,  322 ,  323 . In an embodiment of the present invention, the arm device  320  uses three telescopic devices explained below. The arm device  320  includes a first telescopic device  321 , a second telescopic device  322  and a third telescopic device  323 . 
     One end of the first telescopic device  321  is pivotally mounted to the mounting base  310  at a first joint portion  311 . A first rotating device  312  rotates the first telescopic device  321  relative the first joint portion  311 . Through the pivotal connection to the first joint portion  311 , the first telescopic device  321  selectively rotates within a range of 0 degrees to 180 degrees relative the horizontal axis as denoted by the arrow  301  shown in  FIG. 3 . 
     One end of the second telescopic device  322  is pivotally connected to the end of the first telescopic device  321  at a second joint portion  313 . A second rotating device  314  rotates the second telescopic device  322  relative to the second joint portion  313 . Through the pivotal connection to the second joint portion  313 , the second telescopic device  322  selectively rotates within a range of 0 degrees to 270 degrees as denoted by the arrow  302  shown in  FIG. 3 . 
     One end of the third telescopic device  323  is pivotally connected to the second telescopic device  322  through a third joint portion  315 . A third rotating device  316  rotates the third telescopic device  323  relative to the third joint portion  315 . Through the pivotal connection to the third joint portion  315 , the third telescopic device  323  selectively rotates within a range of 0 degrees to 270 degrees as denoted by the arrow  303  shown in  FIG. 3 . 
     The data reading device  400  is pivotally attached to the other end of the third telescopic device  323  at a fourth joint portion  317 . A fourth rotating device  318  rotates the data reading device  400  relative to the fourth joint portion  317  so that the data reading device  400  could change the angle while retrieving data. The data reading device  400  adjusts the reading angle through the fourth rotating device  318  and hence the angle of retrieving data is variable in order to get a better signal strength between the data reading device  400  and RFID tags when both are vertical. 
     Each rotating device  312 ,  314 ,  316 ,  318  has a driving motor and a transmission mechanism. The driving motors are a motive force source, which drive components coupled with each rotating device through transmission mechanisms. An included angle  340  between two telescopic devices is variable through controlled driving motors to drive the joint portion of coupled portion for rotation. In an embodiment of the present invention, the driving motors could be DC servo motors or AC servo motors, and the transmission mechanisms are speed reduction devices. 
     In  FIG. 4 , each telescopic device  321 ,  322 ,  323  has an upper arm  401  and a lower arm  402 . The lower arm  402  comprises a screw rod  410 , a sliding block  420 , a driving motor  430  and a transmission device  440 . The driving motor  430  is coupled with the transmission device  440 , and rotates the screw rod  410  through the transmission device  440 , which enables the sliding block  420  to move along the screw rod  410 . The sliding block  420  moves in the direction denoted by the arrow  450  shown in  FIG. 4  so that the telescopic device could adjust its length. 
     The upper arm  401  is connected to the sliding block  420  so the length of the upper arm  401  and the lower arm  402  is adjustable to be long or short depending on the sliding block  420  moving. In an embodiment of the present invention, the driving motor  430  could be a DC servo motor or a AC servo motors, and the transmission device are speed reduction devices. 
     In  FIG. 5 , each rotating device  312 ,  314 ,  316 ,  318  and each telescopic device  321 ,  322 ,  323  is controlled by the microcomputer device  202  so the height of the robotic arm device  300  is changed to get a better signal strength according to the position of RFID tags. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.