ACTA TECHNICA NAPOCENSIS

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1 69 TECHNICAL UNIVERSITY OF CLUJ-NAPOCA ACTA TECHNICA NAPOCENSIS Series: Appied Mathematics, Mechanics, and Engineering Vo. 60, Issue I, March, 07 CAD MODEL OF THE RTTRR MODULAR SMALL-SIZED SERIAL ROBOT Ovidiu-Aureian DETEŞAN Abstract: the paper presents the CAD mode of the RTTRR-type moduar sma-sized seria robot. After a short description of the rotation and transation modues from the mechanica structure of moduar smasized robots, the concept of moduarity is appied on the design of the RTTRR-type sma-sized robot, which can be used in a variety of technoogica processes, such as: manipuation, assemby, sorting, packaging, quaity contro and testing. Key words: moduar robot, CAD mode, sma-sized robot.. INTRODUCTION The speciaized industria sma-sized robots rise the probem of buiding a arge constructive range of robots, starting from the simpe robots, with ow fexibiity, to the smart robots, with controed mutipe interactions with the environment. One of the mechanica soutions to this probem is the robot moduarity approach []. This concept impies the production of a certain number of standard modues which combined differenty and efficienty, ead to a variety of modes, different in compexity and appication fieds. Fig. The structure of the rotation modue The buiding of industria sma-sized robots, regardess of their appicabiity domain, has to respond to functiona requirements of the technoogica process they are impemented in, ensuring a proper workspace to the operation they have to execute, in given kinematic and dynamic conditions and assuming a high reiabiity. These requirements impy achieving of transation and rotation modues which make use, instead of siding friction, the roing friction, ensuring, aong with friction forces consideraby ower, a better dynamic response of the robot mechanica structure [].. ASPECTS REGARDING THE BUILDING OF ROTATION MODULES The rotation modues from the mechanica structure of the sma-sized robots ensure the rotation motion about a fixed axis (joint axis), of certain robot s parts. The rotation modues have in their structure, generay, actuation eements (usuay eectric motors, DC or stepper), motion transmission eements (speed reducers, gears, bas or roer screws, bets, fexibe wires) and connection parts (fanges, screws, rods etc.) []. The direct drive modues are a specia case in the buiding of rotation modues. The essentia pecuiarity is their direct connection to the actuator axis, without the need of a speed reducer, gears or other motion transmission eements.

2 70 Fig. Panetary speed reducer 6 The rotation modue presented in fig. is the standard rotation modue from the structure of RTTRR sma-sized robot. The main component is the drive/speed reducer assemby, consisting in a DC motor () and a panetary speed reducer (). The panetary speed reducer from fig. has the input pinion () connected to the DC motor shaft, three identica sateite gears (), which are ocated between the pinion () and the inner toothed crown (). The sateite gears transmit the rotation motion to the soar arm (), connected to the output shaft () of the speed reducer.. ASPECTS REGARDING THE BUILDING OF TRANSLATION MODULES The transation modues from the sma-sized robots mechanica structure are required to ensure the reative inear motion of the robot s parts. Fig. presents the standard transation modue used in the structure of RTTRR smasized robot and this aso coud be used in the buiding of other sma-sized robots [], [], [6]. The basic principe of the transation modue operation is the conversion of the rotation motion given by the drive/speed reducer assemby () into inear motion, by means of a ba screw (), fixed with bearings to its ends. The screw rotation motion is transmitted to the sed () which contains the nut (6) and the roing guides (), which ead the sed on the two ongitudina coumns (). The CAD mode of a roing guide is presented in fig.. Fig. Transation modue structure. THE MECHANICAL STRUCTURE OF RTTRR SMALL-SIZED ROBOT Combining the above described rotation and transation modues in an adequate way, according to the requirements of the technoogica process to be impemented in, different particuar robot structures may resut. One of them is the RTTRR-type robot (fig. ), a moduar sma-size robot with five degrees of freedom. There are in its structure: the support () of the robot s base, the rotation modue () of the robot arm, having a vertica rotation axis and a generaized coordinate q. The transation vertica modue () is attached to it, having the generaized coordinate q. The sed of the modue () is attached to the sed of the next transation modue (), which makes a horizonta inear dispacement, with the generaized coordinate q, having the function Fig. Roing guide

3 7 6 7 Fig. RTTRR sma-sized robot, zero-configuration of extending / withdrawa of the robot arm. At the end of the modue () there is the orientation modue of the gripper, having two degrees of freedom, consisting in the rotation modue (), which performs a rotation with respect to a vertica axis, with the ange q, and the rotation modue (6), executing the gripper (7) orientation, about its symmetry axis, with the ange q. Situated at the end of the open kinematic chain of the seria moduar smasized robot, the gripper (7), designed to perform simpe manipuation tasks, has two straight fingers which cose the gripper by a reciproca transation motion, ensuring the grasping of the manipuated object. According to the robot s task and to the necessary technoogica operation, the gripper can be repaced by another type of end-effecter, such as: muti-fingered gripper, painting pisto, weding head, rotary machine toos etc. Some particuar robot configurations are described as foow, each of them presenting the maximum strokes in the transation modues and some particuar robot positions obtained by the anguar dispacements in the rotation joints. Fig. presents the robot into the conventionay chosen zero-configuration, i.e. zero vaue of the generaized coordinates qi, i =,. Fig. 6 specifies the maximum dispacement in the vertica transation joint, qmax, ensuring the ifting of the robot arm into the upper position. Fig. 6 RTTRR sma-sized robot, q max dispacement Fig. 7 RTTRR sma-sized robot, q max dispacement Fig. 8 RTTRR sma-sized robot, q max dispacement, front view

4 7 Fig. 9 RTTRR sma-sized robot, q max, q max dispacement Fig. 7 and 8 present in two different views (trimetric view and front view) the maximum dispacement in the horizonta transation joint, obtaining the extreme (qmax) position from the ower horizonta pane of the gripper and the maximum operation radius (the reach) of the robot arm. Fig. 9 combines the maximum dispacement in the two transation joints, qmax and qmax, giving the extreme end-effecter position in the upper horizonta pane. In fig. 0 and fig., keeping the maximum strokes in the transation joints, the whoe robot assemby is rotated from the base rotation joint with q=90 and q=80. Fig. RTTRR sma-sized robot, q = 80, q max, q max dispacement From the ast configuration, the gripper is rotated with q=80 (fig. ), being therefore oriented towards the vertica transation axis. Fig. presents, eventuay, the horizonta orientation of the gripper by the anguar dispacement with q=90 of the ast rotation joint of the orientation mechanism. The equivaent kinematic diagram of the robot is presented in fig.. The constructive dimensions, as resuted from the CAD mode, are: 0 6 =.0 mm; = mm; =.0 mm; =8.60 mm. = 7 mm; = 0 mm; =0 mm; () Fig. 0 RTTRR sma-sized robot, q = 90, q max, q max dispacement Fig. RTTRR sma-sized robot, q = 80, q max, q max, q = 80 dispacement

5 7 The mass centers are characterized by the foowing position vectors, having the components in mm: r C = 0.00 ;.7 ; = = = 0.00 ; = (). CONCLUSIONS Fig. RTTRR sma-sized robot, q = 80, q max, q max, q = 80, q = 90 dispacement The masses of the modues, after setting the proper density of the component materias, are the foowing: M =.0707 kg; M =.99 kg M = 8.67 kg; M =.9 kg () M =.660 kg. The obtained CAD mode is usefu in the study of the possibe impementations of the RTTRR sma-sized robot. Using this mode, the shape and voume of the robot workspace can be anayzed, eading to the concusion that this robot can be used in certain technoogica processes. The obtained geometric dimensions, together with the mass distribution eements (masses, mass centers and moments of inertia), taken from the CAD mode properties, are usefu in the numeric simuation of the kinematic and dynamic behavior of the RTTRR sma-sized robot [7], [8], [9], [0]. Fig. The kinematic diagram of the RTTRR sma-sized robot

6 7. REFERENCES [] Angees, J., Fundamentas of Robotic Mechanica Systems - Theory, Methods, and Agorithms, Springer Internationa Pubishing, Switzerand, 89 p., 0, ISBN [] Deteşan, O.A., Cercetări privind modearea, simuarea şi construcţia miniroboţior, Ph.D. Thesis, Technica University of Cuj- Napoca, 007 [] Ispas, Vrg., Pop, I., Ispas, V., Deteşan, O., Osciating Rotation Mechanism for Industria Robots, Acta Technica Napocensis, Series: Appied Mathematics and Mechanics, No.6, vo., Cuj-Napoca, 00, ISSN -87, pp. 7- [] Deteşan, O., Ispas, Vrg., Marcu, L., Aspects Regarding the Mechanica Structure of Transation Modues from the Structure of Parae Robots, Acta Technica Napocensis, Sections: Construction Machines. Materias, No., Cuj-Napoca, 998, pp. - [] Marcu, I. L., Costin, I.O., Costin, I., Deteşan, O., La conception d'un systeme de guidage pour e depacement rapide d'un robot, Acta Technica Napocensis, Sections: Construction Machines. Materias, No., Cuj-Napoca, 998, pp. -8 [6] Marcu, I. L., Costin, I.O., Costin, I., Deteşan, O., Contributions a a reaisation d'un guidage pour e depacement axiae rapide d'un modue d'un robot, Acta Technica Napocensis, Sections: Construction Machines. Materias, No., Cuj-Napoca, 998, pp. 9- [7] Deteşan, O., The Definition of the Robot Mechanica Structure Using the Symboic Computation in Matab, Acta Technica Napocensis, vo., no., Cuj-Napoca, 008, ISSN -87 [8] Deteşan, O.A., The Geometric and Kinematic Mode of RTTRR Sma-Sized Moduar Robot, Acta Technica Napocensis, Series: Appied Mathematics, Mechanics and Enginering, vo. 8, nr., p. - 8, Cuj- Napoca, 0, ISSN -87 [9] Deteşan, O.A., Vahnovanu, A.D., The Dynamic Mode of RTTRR Seria Robot Iterations Outwards and Inwards the Robot s Mechanica Structure, Acta Technica Napocensis, Series: Appied Mathematics, Mechanics and Enginering, vo. 9, nr., pp. -, Cuj-Napoca, 06, ISSN -87 [0] Deteşan, O.A., The Dynamic Mode of RTTRR Seria Robot The Determination of the Generaized Driving Forces, Acta Technica Napocensis, Series: Appied Mathematics, Mechanics and Enginering, vo. 9, no., pp. - 8, Cuj-Napoca, 06, ISSN -87 Modeu CAD a minirobotuui seria moduar RTTRR Rezumat: Lucrarea prezintă modeu CAD a minirobotuui seria moduar de tip RTTRR. După o scurtă descriere a modueor de rotaţie şi transaţie din structura mecanică a miniroboţior moduari, în proiectarea minirobotuui RTTRR este apicat conceptu de moduaritate, robotu rezutat putând fi impementat într-o varietate de procese tehnoogice, cum ar fi: procese de manipuare, asambare, montaj, sortare, ambaare, testare şi contro a caităţii. Ovidiu-Aureian DETEŞAN, Ph.D. Eng., Associate Professor, Technica University of Cuj- Napoca, Department of Mechanica System Engineering, e-mai: Ovidiu.Detesan@mep.utcuj.ro, Office Phone: , B-du Muncii, no. 0-0, Cuj-Napoca, Romania.