Engineering Design of Guidance System of 6R Telerobot based on DTMF

Transcription

1 Int J Advaned Design and Manufaturing Tehnolog Vol. 7/ No. 3/ September Engineering Design of Guidane Sstem of R Telerobot based on DTMF M. H. Koraem* Roboti Researh Laborator Center of Exellene in Experimental Solid Mehanis and Dnamis Shool of Mehanial Engineering Iran Universit of Siene and Tehnolog Tehran Iran hkoraem@iust.a.ir *Corresponding author S. R. Nekoo & A. H. Koraem Roboti Researh Laborator Center of Exellene in Experimental Solid Mehanis and Dnamis Shool of Mehanial Engineering Iran Universit of Siene and Tehnolog Tehran Iran rafee@iust.a.ir hkoraem@iust.a.ir Reeived: April 04 Revised: 4 Ma 04 Aepted: 3 June 04 Abstrat: In this artile the advantages of navigation based on dual tone multiple frequenies (DTMF) tehnique through teleouniation lines is studied. First the alulations of diret and inverse kinematis of the manipulator in omputer are transferred to the PIC miroproessors enter. Next eah PIC is required to ontrol and automate the relevant link separatel. The main purpose of this work is making it possible to ontrol the robot via a telephone line without a modem. In order to appl this idea omputer has analed the data reeived from the operator and inserts the neessar instrutions through the serial port using AVR miroontroller in the embedded hardware at the phone line and sending them to the robot hardware. Then the robot performed the proesses as a losed loop design and provided the neessar feedbak for the omputer. Real-time ontrol low volume of software and hardware omputations and the possibilit of using the phone lines with low and medium bandwidth in addition to ADSL lines simultaneousl are the speial features of this method. In the proposed method ontrol data and the orresponding feedbaks are transmitted as the remote losed loop ontrol whih an be ombined in the developing stages with other ontrol methods suh as neural networks whih results the maximum produtivit. At the end of this work examination of the time dela of tele-ontroller sstem and experimenting aording to the ISO983 standard speifi to the aura of the robot is arried out. Kewords: Dual Tone Multiple Frequenies ISO983 Teleportation Telerobot Time Dela Referene: Koraem M. H. Nekoo S. R. and Koraem A. H. Engineering Design of Guidane Sstem of R Tele-robot based on DTMF Int J of Advaned Design and Manufaturing Tehnolog Vol. 7/ No pp Biographial notes: M. Habibnejad Koraem reeived his BS and MS in Meh. Eng. from Amir kabir Univ. of Teh. in 98 and 987 respetivel. He obtained his PhD in Meh. Eng. from the Univ. of Wollongong Australia in 994. He is a Professor in Meh. Eng. at Iran Univ. of Siene and Teh. S. Rafee Nekoo reeived his BS in Meh. Eng. from the Aad Univ. south branh in 007 and MS in Meh. Eng. from Iran Univ. of Siene and Teh. in 00. He is presentl PhD student in Meh. Eng. in Iran Univ. of Siene and Teh. A. Habibnejad Koraem is presentl MS student in Meh. Eng. in Iran Univ. of Siene and Teh.

2 8 Int J Advaned Design and Manufaturing Tehnolog Vol. 7/ No. 3/ September 04 INTRODUCTION Reentl the ontrol and navigation of sstems via internet were inreased []; however the time dela is a hallenging issue in these sstems. The usages of remote ontrol sstems via internet in different areas suh as biomehanis automation vehiles and militar industries are highlighting the importane of this tehnique. The oenement of using teleportation sstem was frequen modulation in network where this method developed fast via internet. For the first time a six degree-of-freedom robot arm was ontrolled using internet []. In a similar work a robot arm was navigated via network onsidering the data transferring protool [] where the omputer was used as master and slave. The tele-garden robot for using in the field [3] a PUMA arm for painting [4] and tele-robot Max [] are some of the examples in this area. Karad et al. proposed the navigation of a mobile robot via teleportation based on DTMF []. Keber et al. presented the ontrol of a PUMA arm with internet network and simulated the problem with arm details [7]. Zhenuan et al. introdued a ombination of different tehniques based on image reonstrution for prediting the diretion of motion to improve the sstem performane [8] [9]. Tele-eho robot (TER) whih had two master and slave parts was presented in ref. [0]. In the sstem a Matrox Meteor board with a FFMPEG librar hanged an image 40*480 Pixel to an 8 bit ode for transferring. In the mentioned researh most of the alulation was done b omputer and generall the had massive hardware. The real time working of these works are depended on the network speed; on the other hand man of them were designed for loal network. These reasons are the main motivation of the present researh to propose an algorithm based on DTMF for ontrolling R robot via teleportation. omputer whih is angular position of links. R robot and the ontrol unit are presented in Fig.. First joint revolves around vertial axis. Seond third and the fourth joints have horiontal revolution axis and make vertial movements for the arm. The fifth and sixth joints make pith and roll rotations. The onfiguration of the robot is shown in Fig.. Fig. R robot and its ontrol unit STRUCTURE OF A TELE-ROBOT R artiulated robot is a manipulator with six degree of freedom inluding six DC motors with independent gearbox for eah. Like other tele-robots it onsists of master and slave elements. The main devies inlude a omputer in the master a main digital board whih six driver boards for motors in the slave and two teleontrol boards one in the master and one in the slave. In fat the struture of the ontroller is divided into two parts: ontroller and tele-ontroller. The ontrol unit onsists of different setions. The main ontroller is on the motherboard where it reeives the input oands from tele-board and sends bak the feedbak to Fig. R robot mehanial onfiguration In this work ontrol of the robot based on transferring data via telephone line is expressed. In this method the modulations are done in dual tone form for sending and reeiving data. Moreover the angle variations of the links are sent from the slave to the master in real time. This modulation has the following advantages: High preision in transferring digital data due to using two high and low frequenies for eah four bit data simultaneousl as presented in Table. Redution in hardware and software implementation.

3 Int J Advaned Design and Manufaturing Tehnolog Vol. 7/ No. 3/ September Being dnami for having different length of frames for transferring data. Capabilit of using all lines of telephone sstems. No need to modems in master and slaves. In the proposed idea both main proessors are independent and apable of sending and reeiving different frames in phone lines. The data transferring speed is inreased due to omitting loal filters. Table The values of frequenies in high and low modulation ACTIVE INPUT OUTPUT FREQUENCY (H) %ERROR SPECIFIED ACTUAL L L L L H H H H MODEL OF THE ROBOT In order to obtain the equations of diret kinematis the Denavit-Hartenberg parameters of the arm are needed to be presented (Fig. 3). The parameters of the arms are presented in Table. Fig. 3 Shemati of R robot manipulator Using Denavit-Hartenberg parameters and transformation matries as: T T T T3 T4 T T () nx ox ax px n o a p T () n o a p Where n o a vetors are elements of rotation matrix and p vetor is end-effetor position of the robot. The details of the matrix is presented as: n x CSS CC 34CC S34 S (3) C C S C S S S n C 34 34S (4) n o x C CS34 C34 S () SSS CC S34 C34 C34CS () C C S C S S o C SS (7) o C34C CS34 S (8) a x CS CC 34S (9) a CC C34SS (0) a S S 34 () a C a p x C () Sd C C3a3 C34 4 a S d a C a p C C d (3) p S C3a3 C34 4 Sa S3a a S d. 4 3 d S 34 a S d Table Denavit-Hartenberg parameters of the arm (4) Join a i d i a i( ) θ i motion number (i) 0 d= θ Link a =. 0 0 θ Link 3 a 3= 0 0 θ 3 Link3 4 a 4= θ 4 Link4(Yaw) θ (Pith) 0 d=.8 0 θ (Roll) The inverse kinematis for manipulators with less than three degree of freedom ould be found analtiall but for ompliated arms the inverse kinematis equations are not eas to find. The inverse kinematis equations of this manipulator are presented as follows: p da tan () px dax ()

4 0 Int J Advaned Design and Manufaturing Tehnolog Vol. 7/ No. 3/ September 04 ( ) tan d a C axs (7) p C pxs a tan axc a S (8) for 0 (9) o xs oc tan for nc nxs (0) () ( ) w tan q u tan () w t q u as 3 tan t ac (3) (4) t C px S p dsc34 a4c34 () u p d a4s34 dss34 () a3 t u a w (7) a q ( t u ) /. (8) 4 HARDWARE STRUCTURE The ontrol unit of this tele-robot has three main parts: a) Motherboard: The motherboard is designed for providing and distributing motors power. Additionall it should provide the ouniation between the ontrol setion and the robot arm. The drivers of the motors are also set on the motherboard as presented on Fig. 4. Based on the program the output data of kinematis equations in omputer are sent to the motherboard via RS3 port after hanging the voltage level to TTL with Max3. This data is sent to the miroproessors PIC F87A whih have the ontrol algorithm of the method. The responsibilit of the miroproessors also inludes the motors snhroniation feedbak omputation and alulation of PWM (Fig. ). Coands are sent to transistors LMD800 where the provide the motors power. Optial ounters at the top of the shafts of motors suppl the feedbaks. Fig. 4 Motherboard of R robot manipulator Fig. PIC F87A board b) The hardware of tele-ontroller: The AVR miroontroller is hosen as the main proessor of this part due to having suitable omputation speed to prevent time dela in transferring and operating. ATMega4 proessor is the link between the master and slave whih transfers the data of kinematis equations. Figure shows the teleontroller diagram. MT8888CE is a hip whih has the responsibilit of sending and reeiving data onsists of filters and digital oding funtions. In its filtering part swithing tehniques for high and low frequenies and digital oding for generating signals are used. The outer devies of hip are small in sie where it is simpl a differene operational amplifier and a rstal lok. Low power onsumption apabilit of variation of internal gain and guard time are the advantages of this devie [8]. HIN3 has RS3 output port and hanges the voltage level to TTL. CH87D plas the buffer role in the board and prevents interferene of sending and reeiving signals. ATMega4 is the proessor of tele-ontroller board and it is the link between different modes of MT8888CE with input ontrols and output to RS3. Framing in software prograing is also its dut. This board has the pad for entering a phone

5 Int J Advaned Design and Manufaturing Tehnolog Vol. 7/ No. 3/ September - 04 number and a LCD for presenting the neessar data (Fig. 7). Fig. Tele-ontroller diagrams SOFTWARE STRUCTURE a) Software of ontrol unit: The ontrol unit software has three setions. The first setion is the program in PC where this program is written in Delphi prograing language inluding the omputation of the kinematis equations. The seond setion is the program in motherboard whih reeives the data of PC via serial port and applies them to motor derivers. The third setion is the program of the ontrol board where the PWM perentages of motors are omputed in this part. The orretion of mehanial errors are onsidered in this program too. b) Software of tele-ontroller unit: The interfae of this program has the following responsibilities: Defining the mode of master or slave. The waiting mode of slave for reeiving master s oands. Automati dialing using the tele-ontroller board in master mode. Displaing different states to operator. Identifiation of slave b master. Fig. 7 Tele-ontroller hardware iruits In order to detet the master b slave a four-bit random data is sent to master and the response is another bitmath for the ode whih slave reeives. The orret sending and reeiving of this ation onfirms the true onnetion. The framing of the data after detetion is sent as a hex ode to delare the oenement of the proess. Then the first four-bits present the number of motors and its diretion and the value of links angles (Fig. 8). Fig. 8 Framing struture

6 Int J Advaned Design and Manufaturing Tehnolog Vol. 7/ No. 3/ September 04 EXPERIMENTS In order to test a robot different parameters must be taken into onsideration: the aura of the assembl manufaturing toleranes external fores frition and the robot ontroller. The following tests are based on ISO983standard. Table 3 Results for 0 experiments The errors are alulated based on Eq. (9) where AP p is the position error and AP x AP AP are the errors in X Y Z axes. The results of the tests are shown in Table 3 and the average of the motion in Table 4.The test result is presented in Fig. 9. b) Position repeatabilit test This test was run for a path and the result is presented in Fig. 0. No. x j j j Table 4 Average position of motion in axis Fig. 0 Result of repeatabilit test ) Dela test In order to run this test two different phone lines were used. This set of test examined the tele-ontroller board. The result of the dela test is presented in Table. Table Dela test result Repetition Send Time of Master Reeive Time in Slave Dela Time Fig. 9 Result of position error a) Positioning aura test: In this test a set point is defined for the arm where this point is heked n times as target. The position of the desired point is defined in the X Y Z axis. X j Y j Z j are the experimental measurement of displaement. AP p AP x x x x x AP AP (9) :4 : 0:4 :3 00:00 : :0 :0 :0 :07 00:00 : : : : :4 00:00 : 7:4 :0 7:4 : 00:00 : :0 :08 :0 :09 00:00 : 4:3 :3 4:3 :4 00:00 : 7:4 :4 7:4 : 00:00 : :0 :08 :0 :09 00:00 : 8:3 :3 8:3 :4 00:00 : 8: :3 8: :4 00:00 :

7 Int J Advaned Design and Manufaturing Tehnolog Vol. 7/ No. 3/ September CONCLUSION In this artile a tele-ontroller for navigation of R manipulator was proposed based on DTMF tehnique. Redution in hardware devies ompatibilit with phone lines and improving the ouniation speed are the advantages of this method. This method also does not need modem and internet and as a result it works without loal filters. The result of this method was satisfator based on ISO standard. REFERENCES [] Goldberg K. Masha M. Gentner S. Rothenberg N. Sutter C. and Wrigle J. Desktop teleportation via the World Wide Web Pro. IEEE Int. Conferene on Robotis and Automation 99 pp [] Lu S. J. Chen B. M. KO C. C. Kee Sh. T. and Poon M. Web-based Robot for Remote Experiments The Fourth International Conferene on Control and Automation (ICCA'03) Montreal Canada June 003. [3] Goldberg K. Santarromana J. Beke G. Gentner S. Morris R. Wiegle J. and Berger E. The Telegarden Proeedings of ACM SIGGRAPH 99 pp [4] Stein M. Painting on the World Wide Web: The Puma Paint Projet IEEERSJ International Conferene on Intelligent Robots and Sstems 998 pp [] Ferworn A. Roque R. and Vehia I. MAX Wireless teleoperation via the World Wide: Web Pro. IASTED Conf. on Robotis and Appliations Santa Barbara 8-30 Ot. 999 pp. 8-. [] [7] arh_projets/interfae_development/telerobot_interf ae.htm [8] Deng Zh. Jagersand M. Preditive displa sstem for tele-manipulation using image-based modeling and Rendering Intelligent. Pro. Robots and sstems IROS 003 Vol. Las Vegas USA 003. [9] Charles C. Nguen C. Zhou Z. L. and Mosier G. E. Joint-spae adaptive ontrol of a redundant telerobot manipulator Pro. 4th IEEE International Smposium on Intelligent Controls Alban New York September 989 pp. 9-. [0] Vilhis A. Troa J. Cinquin P. Masuda K. and Pellissier F. A new robot arhiteture for teleehograph IEEE Transation on Robotis and Automation Vol. 9 No. Ot []