Design of a Radioactive Source Sampler Based on CPAC

Transcription

1 IJCSI International Journal of Coputer Science Issues, Vol. 0, Issue, No, March 03 ISSN (Print): ISSN (Online): Design of a Radioactive Source Sapler Based on CPAC Bin Yang, Zhenyu Wang Departent of Autoation Engineering, The Engineering and Technical College of Chen Du University of Technology, Leshan, Sichuan Province, 64007, China Departent of Autoation Engineering, The Engineering and Technical College of Chen Du University of Technology, Leshan, Sichuan Province, 64007, China Abstract This paper puts forward a design project of sapler for solving the difficult proble of radioactive source sapled by anual work because of radioactive source s radioactivity. The project includes echanical body s design, controller s design, and controller s realization. According to echanical body s otion characteristics, advances an iterative learning algorith of exponent variable-gain to design controller for the radioactive source sapler whose anipulator ar can follow the given tracks. The design can get satisfying track following control effect by coputer siulation, and can content control deands of sapling process. On the realization of controller, applies Coputer Prograable Autoation Controller (CPAC) ade in Googol Technology to sapler and gives its hardware s realization ethod. Now the prototype tested has already substituted for tester to finish autoatic sapling process in accordance with sapling progra set in advance. Keywords: CPAC, otion controller, iterative learning, radioactive source sapler. source sapler for realizing to autoatically take radioactive sources.. Working Principle of Mechanical Body There are nine sources stored in the radioactive source library. They are arrayed in three lines and three rows. To realize autoatic sapling, a echanical sapler designed ust have two active joints at least, and can freely do rotary otion. Two active joints and its rotary otion can easily adjust gripping device s position according to the position of source sapled. So a sapler of radioactive source can be design as follows.. Introduction The Southwestern Institute of Physics is the biggest controlled nuclear fusion experiental base in Asia. Its ain research directions are agnetic confineent of controlled nuclear fusion. During the controlled nuclear fusion experients, cannot be without use of radioactive eleents (Cobalt-60, Cesiu-37, and Iridiu-9 etc). The sources are stored in the radioactive source library in Le Shan base. When need the radioactive sources, they are sapled by anual work fro the underground to the workbench. It is dangerous that the sapling tester is placed in the radiation environent. In order to solve the proble, an autoatic sapler is designed to substitute for tester. With the developent of otion control technology, the universal otion controllers are widely and successfully used in robots, CNC achine tools, assebly lines, laser processing, and PCB drilling and illing euipents etc. The technology also provides reliable basis for solving autoatic sapling proble. In the design, applies the CPAC that is an universal otion controller ade in Googol Technology to the radioactive turbine reducer, drive otor, 3 chassis, 4 rotary syste, 5 auxiliary hoist syste, 6 operation panel, 7 hoist otor, 8 hueral otor, 9 hueral ar, 0 joint otor, gripping ar, gripping device Fig. Mechanical structure of sapler. The sapler of radioactive source is ade of turbine reducer, drive otor, chassis, rotary syste, auxiliary hoist syste, operation panel, hueral ar, gripping ar, and Copyright (c) 03 International Journal of Coputer Science Issues. All Rights Reserved.

2 IJCSI International Journal of Coputer Science Issues, Vol. 0, Issue, No, March 03 ISSN (Print): ISSN (Online): gripping device etc. The sapler of radioactive source s working principle is as follows. Before sapling, a radioactive source gripped is placed in the lifting container, which is under the floor at 0.5 eters deep. When need saple, tester presses the buttons of nuber one to nuber nine on the operation panel or on the control desk in the control roo outside the source library. Then the sapler coputes each joint changed the angles accurately according to the position of the radioactive source gripped, and selects corresponding control progra of the position. The gripping device will precisely ove into the position of the radioactive source gripped and open its jaws. When a sensor detects a right depth s signal, the hoist syste stops dropping and its jaws begin to close up. At last, adjusts the two ar joints angle or auxiliary hoist syste for slowly hoisting gripping device and accurately placing the saple on the workbench. The whole course entirely realizes autoatic control. bearings and the thrust bearing. The guide screw whirls at given speed. At the sae tie, the lifting slide carriage whose otion stroke is 400 illieters oves along the guide post. 3. Two-joint Mechanical Ar Two active joints echanical ar can be adjusted to suitable angles by two AC servo otors. Two-joint echanical ar s otion trajectory is deterined by the control progra. Nine radioactive sources have nine independent control progras because of their different position. Mechanical ar s controller design will be deterined for its trajectory tracking in the back of the article. 3.3 Rotary Syste As in Figure 3, rotary syste consists of shaft end retaining ring, rotary disk, joint flange, bearing cover, bearing seat, bearing cover, and rotary axis. 3. Mechanical Structure 3. Auxiliary Hoist syste The otor drives a guide screw to whirl, the guide screw s rotation will convert into linear otion of hoist and drop of the gripping device. shaft end retaining ring, rotary disk, 3 joint flange, 4 bearing on the cover, 5 bearing seat, 6 bearing under the cover, 7 rotary axis Fig.3 Rotary syste. The bearing seat supports two tapered roller bearings. The rotary axis whirls in the bearing, which is fixed in the bearing seat, and is fixed with the shaft end retaining ring and the joint flange through a flat key. The joint flange is fixed with the rotary disk by screws. The otor drives the rotary axis to whirl and transits torue to the rotary disk, which drives the whole rotary hoist syste and gripping syste whirling. 3.4 Gripping Syste below the botto plane, lifting slide carriage, 3 guide sleeve, 4 guide post, 5 above the botto plane, 6 guide screw, 7 nut, 8 bearing seat Fig. Auxiliary hoist syste. The three guide posts are fixed reliably by the two botto planes. And the guide screw s radial and axial oveents can be located by the bearing seat, the pillow block Gripping syste ainly includes a peranent agnet low speed synchronous otor, fixed plate, screw, slider, positioning axis, T-frae, link, and gripper. Figure 4 shows the gripping syste s working principle. The peranent agnet low speed synchronous otor drives the screw to whirl. Then the slider can slide up and down, and slider can drive T-frae. The gripper turns around the positioning axis through the lever s effect. The Copyright (c) 03 International Journal of Coputer Science Issues. All Rights Reserved.

3 IJCSI International Journal of Coputer Science Issues, Vol. 0, Issue, No, March 03 ISSN (Print): ISSN (Online): gripper s rotary otion is liited by travel switch within the 0~5 range. peranent agnet low speed synchronous otor, fixed plate,3 screw, 4 slider,5 positioning axis, 6 T-frae, 7 lever, 8 gripper Fig.4 Gripping syste. 4. Matheatical Model In order to realize autoatic control of the sapler, a controller ust be designed for the two-joint echanical ar s trajectory tracking. However getting atheatical odel of the syste is only the first step. The radioactive resource sapler shown in Figure can be siplified to the odel as follows. Fig.5 The odel siplified. Assue that point A is the syste s the origin of coordinates, point D is the centroid of lever, and point E is the centroid of lever. The centroid D s coordinate is the ( x, y ), the active joint B s coordinate is the ( x, y ), the centroid E s coordinate is the ( x, y ), and gripping device C s coordinate is the ( x, y ). In Figure 5, there are soe ain physical variables shown in Table. Table : Sybol, Meanings and Units for Physical Variables Sybol Meaning Unit l length of the lever eter l length of the lever eter ass of the lever kilogra ass of the lever kilogra 3 ass of the active join B kilogra 4 ass of the gripping device kilogra angle between the lever and the x-axis radian angle between the lever and the lever radian s extension line According to the Figure 5, the syste s total kinetic energy T is that the lever s rotational kinetic energy T around the origin A couples with the lever s total kinetic energy T including rotational kinetic energy around the active join B and it s parallel oving kinetic energy, and couples with the active joint B s rotational kinetic energy T and gripping device s oving kinetic energyt. Considering above entioned the otion syste s kinetic energy T we have: T = T + T + T + T = l 6 + ( x + y ) + l ( + ) 6 + 3l + 4 ( x+ y ) () The syste s total potential energy can be expressed as follows: V = gy + gy + 3gy + 4 gy () In this paper, gets a atheatical odel of the echanical ar via Lagrange Euation. According to Lagrange Function L=T-V, euation () and euation () is substituted into the following Lagrange Euations. ì d L L ï ( )- = t dt ï (3) í d L L ï ( )- = t ïdt î Where t and t are generalized force. Thus, can get relational expressions (4) and (5) as follows: 7 [ llc+ l + 4ll C+ 4l + ( ) l ] + ( llc + l + 4ll C + 4l ) - ( ll S + 4ll S + ll S + 4llS ) + ( glc + glc + glc + gl C + gl C + gl C =t -t (4) ) d 7 ( llc + l + 4llC + 4l ) 7 + ( l + 4l ) + ( lls + 4 lls ) + ( glc + 4glC ) =t -t (5) d In expression (4) and expression (5), C is Cos ( ), C is Cos ( ), C is Cos ( + ), S is Sin ( ), generalized Copyright (c) 03 International Journal of Coputer Science Issues. All Rights Reserved.

4 IJCSI International Journal of Coputer Science Issues, Vol. 0, Issue, No, March 03 ISSN (Print): ISSN (Online): force t and t are the driving torue of the first and second joint, and t and d t are outside the disturbance. d Euation (4) and euation (5) are seeking the atheatical odel of the echanical ar. This is a typical nonlinear syste, whose control goal is that the end of the echanical ar s position and speed, etc. can track a given ideal trajectory via given the driving torue of each joint. The following will detail a controller design ethod for trajectory tracking. 5. The Exponent Variable Gain Iterative Learning Because iterative learning control algorith is siple, and is able to achieve high precision trajectory tracking control in the given tie, it is widely used in nonlinear syste s control objects. Its basic control principle is: to set the desired output and the each running initial state, repeats learning control algorith according to a certain calculation within a given tie so that akes the control input uk ud, and akes the syste s output yk yd. According to the control object s nonlinear feature, the paper uses closed loop variable gain exponential D-type iterative learning control algorith to realize the echanical ar s trajectory tracking control. Its basic control law is as follows. l t uk+ = uk + kde ( d - k+ ( t)) (6) Above iterative learning control law s control block diagra is shown in Figure 5. Its proof of convergence sees related references. u y k k yd Controlled Object u k uk Iterative Learning Law Controlled Object Iterative Learning Law Fig.5 Control block diagra. By the radioactive sources sapler s echanical design, can know the following paraeters: =. 447kg, = 4. 3kg, = kg, = kg, l = , l =. 55. In order to verify the effectiveness of the control law (6), applies MATLAB to siulate and to analyze under the specified conditions. If the position instruction of the two joints respectively is sin (3t) and cos (3t), disturbance ter is -t t d = [0.sint 0.( -e )], and the controlled object s zero initial state is x(0)=[0 3 0], builds odular SIMULINK siulation subroutine as follows: e k yk e k - - yd Fig.6 SIMULINK siulation subroutine. In Figure 6, S-Function is controlled object subroutine, S- Function is a given input trajectories subroutine, and S- Function is variable gain exponential D-type iterative learning controller. The syste s siulation result based on Matlab software is shown as Figure 7, Figure 8, and Figure 9. Copyright (c) 03 International Journal of Coputer Science Issues. All Rights Reserved.

5 IJCSI International Journal of Coputer Science Issues, Vol. 0, Issue, No, March 03 ISSN (Print): ISSN (Online): a good control effect for the two-joint echanical ar of the radioactive source sapler, so can consider the proble of realization of iterative learning controller. 6. Iterative Learning Controller s Realization Fig.7 0 iterations learning tracking process. Following an iterations learning controller will be realized by CPAC ade in Googol Technology to carry out realtie control and anageent for the sapler, so that the echanical ar s oveent can be in accordance with the anticipated trajectory and a predeterined paraeter of the otion. Full nae of CPAC is the coputer prograable autoation controller, which is the controller of an ebedded industrial PC, PLC, and otion controller with stability, anti-interference ability, high reliability, and high value for oney. The CPAC will becoe the core of the control of radioactive sources sapler, and the variable gain exponential D-type iterative learning control algorith is ipleented by CPAC via OtoStudio soft. Then control instructions will be issued by CPAC, and servo otors will be driven by servo drives in accordance with the given trajectory oveent. Figure 0 is the control structure principle realization diagra for the sapler s joints control. Fig.8 The twentieth iterative learning. Fig.0 Control structure principle realization diagra Fig.9 Error nor convergence process. As can be seen fro the above siulation results, iterative learning controller is able to effectively track a given signal and error nor can converge after 0 iterations learning. This also shows that the variable gain exponential D-type iterative learning control algorith has According to CPAC and terinal board interface definition, a dedicated 50PIN cable connects between CPAC controller s AXIS-4 interface and terinal board CN7 interface for reading switches signal on the terinal board interface and axes position signal. And calculates directly to obtain the k+ tie s error signal of the position, and sends the k+ tie s iterative learning control instruction to the two servo drives to drive the two servo otors for coordinated oveent in accordance with the given track. On the terinal board, CN9 and CN are soe general purpose digital I/O interfaces, which can be designed for two sets of buttons. One set is installed in the radioactive source sapler s operational panel; the other set is installed in the control roo outside the source library. This design helps to realize the control in two different places. The test ebers are able to coplete sapling operation in the control roo without entering the source library. In this paper, the iterative Copyright (c) 03 International Journal of Coputer Science Issues. All Rights Reserved.

6 IJCSI International Journal of Coputer Science Issues, Vol. 0, Issue, No, March 03 ISSN (Print): ISSN (Online): learning controller can be realized by CPAC, but the specific circuits will be oitted. In fact, prototype testing has begun, and achieved good effect. 7. Conclusions This paper focuses on a radioactive source sapler s echanical structure design and its controller design for solving the proble of autoation saple. The production of echanical body proves the effectiveness of the design of the echanical structure. On controller design, the closed-loop variable gain exponential D-type iterative learning control strategy is successfully used, and fully takes into account the disturbance of the syste. The siulation results show that the iterative learning controller has good control effect for the two-joint echanical ar. On this basis, puts forward to use CPAC for the syste s control core. Now the prototype has been ade and put into trial operation, whose results is satisfactory and fully realizes autoatic saple without huan intervention. Prototype testing proves that the echanical structure design and control schee is reasonable and feasible, and easy ipleent. Acknowledgents The help of Li Song, Senior Engineer of the Southwestern Institute of Physics in the preparation of this paper is gratefully acknowledged. We also acknowledge the financial support of youth research and developent fund by the engineering and technical college of Chen Du University of Technology. References [] Dong Jiai, Tokaak high confineent operation ode and controlled nuclear fusion through agnetic confineent, Physics, Vol. 39, No. 6, 00, pp [] Han B, Lin X G, Adapt steady state Kalan gain using the noralized autocorrelation of innovations, IEEE Signal Processing Letters, Vol., No., 005, pp [3] Jin Ho SUH, Jin Woo Lee, Young Jin Lee, Antisway control of an ATC using NN predictive PID control, Proceedings of the 30th annual conference of the IEEE industrial electronics society, Busan, Korea, 004, pp [4] Li Maoing, Controller design for -DOF under actuated echanical systes based on controlled Lagrangians and application to the Acrobot control, Frontiers of Electrical and Electronic Engineering in China, Vol. 4, No.4, 009, pp [5] Li Yizhong, Xia Tian, The AGV controller syste design based on CPAC, Mechanical and Electrical Engineering, Vol. 40, No., 0, pp [6] Park K.H, Bien Z. Hwang D.H, A Study on the Robustness of a PID-type Iterative Learning Controller against Initial State Error, International Journal of Systes Science, Vol. 30, No., 999, pp [7] Piao Fengxian, Zhang Qinling, Analysis of convergence rate for iterative learning control, Journal of Northeastern University(Natural Science), Vol. 7, No. 8, 006, pp [8] Xu Yuxing, Soe suggestions on the current application and anageent of radioactive sources, Sci-Tech Inforation Developent and Econoy, Vol. 7, No., 007, pp [9] Zhang Peng, Zhao Hui, Design of force/ position hybrid control based on googoltech industrial robot, Machinery Design and Manufacture, No. 4, 0, pp [0]EI Sayed M. Saad, Medhat H. Awadalla, Hosa Eldin I. Ali, Rasha F. A. Mostafa, Interactive learning for huanoid robot, International Journal of Coputer Science Issues, Vol. 9, No. 4, 0, pp First Author received the Master degree at Wuhan University of Science and technology in 007. Currently, he is eployed at the engineering and technical college of Chen Du University of Technology and engaged in teaching and research work of the autoatic control. His interests are in advanced control theory and applications and echanical and electrical integration technology. Second Author received the Master degree at Jilin University in 007. Currently, he is eployed at the engineering and technical college of Chen Du University of Technology and engaged in teaching and research work of echanical engineering. Copyright (c) 03 International Journal of Coputer Science Issues. All Rights Reserved.