PROPOSAL FOR AN INTRODUCTORY COURSE OF INDUSTRIAL ROBOTICS WITH MULTIDISCIPLINARY SYLLABUS

Transcription

1 PROPOSAL FOR AN INTRODUCTORY COURSE OF INDUSTRIAL ROBOTICS WITH MULTIDISCIPLINARY SYLLABUS Maros Fonsea Mendes, Center of Engineering and Exat Sienes CECE, Paraná Western State University UNIOESTE Foz do Iguaçu, PR, Brazil Abstrat. All over the world the industry s and students interest by Robotis has inreased. In addition to the fasination involving the subjet, this is due to the fat that the robot manipulators an replae humans in dangerous, unhealthy and tedious tasks, in a viable eonomially and effiiently way. Thus, there is a need to expand and improve the eduation in this area, in aordane with the professional world. Several Universities are inluding a basi industrial Robotis ourse in their undergraduate and/or graduate urriula. However, most of these ourses are stritly tehnial and do not approah other important issues related to the subjet. The industrial Robotis has been evolving quikly and it is omplex and multidisiplinary. Besides Mehanial, Eletrial, Control and Computing, it also involves Prodution, Administration and Eonomy, among others. To elaborate a syllabus with all these topis with suitable depth is a hard task. Moreover, the limited time available for a semester ourse is an obstale. The paper presents a proposal of an introdutory ourse on industrial Robotis, multidisiplinary in nature, whih provides solid theoretial foundations. This is a way of trying to unify the introdution to industrial Robotis in the Universities. It desribes the prerequisites, the ourse ontent, the modalities of evaluation and the bibliographial referenes. Aording to the results of teahing it during four years for undergraduate students, the ourse has been proving to be effetive. It an be offered in the final years of undergraduate or at the beginning of graduate Engineering eduations. Keywords: Eduation, Teahing, Industrial Robotis, Roboti Manipulators. 1. INTRODUCTION With the advanes in mehanial, sensors, atuators, hardware and software tehnologies, robot manipulators have exploded in number and omplexity in the last two deades. Atually there are about one million industrial robots toiling around the world and the worldwide investments in 2007 was US$ (Guizzo, 2008). The inrease of robots in the industry has hanged the senario. Some authors onsider that the reation of flexible manufaturing systems using robots was a seond industrial revolution. Therefore, the robots have aquired great importane in Engineering eduation. It is important training the future engineers to attend the industry. Furthermore, several researhes are being developed in this area, therefore speialists are neessary. Robotis is a true multidisiplinary field that inorporates topis from many areas. Often the eduators have diffiult to over all the topis with suffiient depth. Inorporating all the topis into a single ourse is a omplex problem. The industrial Robotis ourse had began to be offered in graduation ourses. Now it is present in nearly all the undergraduation urriula in Mehanial, Eletrial and Automation Engineerings, as optional ourse. This is an ation to modernize the Engineering urriula. Moreover, the interest of students by Robotis has inreased. Thus, a way to unify the several approahes to teahing in this area should be found. The proposal presented in this artile is a ourse for the final year of undergraduation or for the first year of graduation in Engineering. Many Robotis ourses are direted for speifi appliations, so that the foundations are left out. As the ourse proposed here is an introdution, its emphasis is the theory. However a little bit of praties and appliations are introdued to inrease the students motivation. A seond ourse, more advaned, ould have more pratie. Besides, nowadays the industrial Robotis eduation fouses on Geometry, Mehanis, Eletrial, Eletronis and Computing. The ourse presented here also inludes Prodution, Administrative, Eonomial and Soial aspets. The inrease of themes provides a holisti view of the matter (Rafael, 2002). The ourse goal is to give a suffiient bakground of Robotis for the students to be used in some industrial appliations, in a relatively short amount of time. After ompleting the ourse, the students will be able to understand the origin, basi onepts and definitions of industrial robots and to understand and evaluate tehnial artiles and brohures of the area. Furthermore, they may ontinue learning and developing new knowledge. 2. COURSE The ourse presented here is taught into the Eletrial Engineering urriulum at the Paraná Western State University UNIOESTE by the Center of Engineering and Exat Sienes CECE. It was introdued in The ourse is presented in a standard format of letures. It is taught in one semester (16 weeks 64 hours / letures), with four hours per week divided into two meetings. This time is adequate to over the whole program and arry out evaluations (seminary and examination). The prerequisites are: matrix Algebra, integral and differential Calulus, lassial Physis, linear Control and some knowledge of programming.

2 As almost all Engineering ourses, the general objetive is to develop the ability to understand, organize, interpret, reason, investigate, analyze, resolve, ritiize, synthesize, reate, omplete and express (written and verbally). Furthermore, the speifi objetive is to provide initial knowledge of Robotis, involving the origin and evolution, and to present the most ommon industrial robots, the manipulators, from a onstrutive, funtional and appliations points of view. It is expeted that after the ourse, the students will have the basi knowledge neessary for industrial robot manipulators mathematial modeling, analysis and programming. The topis of the ourse, from a maro point of view, are: introdution (history of Robotis and general onepts); omponents and struture of a roboti system and of a robot manipulator; lassifiations of robot manipulators; sensors and atuators applied to Robotis; manufaturing ells using robots (appliations, features and speifiations); kinemati modeling of robot manipulators: introdution to robot manipulators Dynamis; trajetories generation; programming robots theory; introdution to position ontrol of robot manipulators. The methodology of the ourse is based on dialogued letures using blakboard and halk and audiovisual resoures. The approah is onstrutivist (Salvador, 2006). The interpretation, analysis and disussion of texts and problems (by the teaher and students, individually and in groups, inside and outside of the lassroom) are explored. Usually at the beginning of the ourse the students have no idea of the load that manipulators an lift and the preision with whih they an move, for example. Thus, at the opening of the ourse a questionnaire an be applied. It will ask for eah student to talk about the knowledge of Robotis: what is a robot; what are the areas of appliation; what are the differenes between robots and other industrial mahines; what are the maximum preision and maximum load of an industrial robot; et. This allows an initial idea of the students subjet knowledge and it an be used at the end of the ourse by the students assessing their own progress. 3. LECTURES The letures of the ourse are presented below. The items desribe in a resumed way the issues and goals of eah leture and it also suggest how teahing. During the letures it is reommended to give exerises and problems for the students, to establish the knowledge and to develop their intelletual apaity. Leture 01 Presentation The first meeting is used to present the syllabus and the eduation plan. The program, the ourse s organization, the grading proess and the important dates should be disussed. The questionnaire evaluating the students knowledge about Robotis, ited above, an also be applied in this leture. Leture 02 Introdution The origin of the words "robot" and "Robotis" is important to introdue the ourse. From this introdution the students already an see that the siene Robotis sometimes is onfused with fition. In ontrast, an offiial definition of industrial robots, suh as those given by the Robot Institute of Ameria RIA or by the International Organization for Standardization ISO must be provided. While addressing the origin of Robotis, the two prior tehnologies must be presented: remote manipulation and numerial ontrol. Then, the three generations of robots an be disussed. Leture 03 History (Chronology) The Robotis history an be presented through a detailed timeline. This leture explores both the tehnial as fition aspets. The main events should be disussed, and an be ited, for example: 1921 The first referene to the zeh word "robot" in the play RUR (Russum's Universal Robots) written by Karel Capek, whih means fored, slave or subservient labor; 1962 General Motors (plant in Trenton, New Jersey) installed its first robot Unimation, et. The hronology should follow up to the present days. Leture 04 Fixed Flexible Automations The fixed and flexible automations are introdued in this leture, giving the definitions and appliations of eah one and their major differenes. The line of disussion is the fat that the rigid automation, from the deades of 50 to 80, whih use dediated mahines for high prodution apaity, is not applied nowadays due to the very short life yle of the produts. The advantages and disadvantages of eah one, addressing tehnial and eonomi issues should be presented. The three main advantages of using robots: the reation time, debugging and resistane to obsolesene, should be emphasized. Following this, the main goals of Robotis may be shown, exploring: ost redution, produtivity inrease, losses redution, energy savings, elimination of dangerous and unhealthy ativities, improvement of prodution quality, et. Additionally, it is important to note that the robots an be used in ativities that are impossible for humans (omplex and quikly movements, manipulation of small or fragile parts, et.). The leture an be losed onluding about the main justifiations for using robot manipulators in the industry. Leture 05 Roboti System Components In this leture the omponents of a roboti system: manipulator, atuators, sensors, ontroller, drive or power supply and end effetor should be presented. A hardware and software arhiteture for a roboti system should also be shown. The arhiteture inludes: hardware, operating system, ommuniation, exeutive subsystem (adaptation, trajetory

3 generation and ontrol of servomotors) and interpreter program. Finally, the mehanial omponents of manipulators: base, links and joints, should be presented. Leture 06 Definitions and Conepts To make learer the definition of robots, the "pseudo" robots must also be presented. They are devies, alled robots by mistake, similar to robots and use some Robotis features. Can be ited: prostheses, teleoperated equipment, exoskeleton, transport mehanisms, et. In this leture the basi onepts and definitions, suh as workspae, auray, resolution, repeatability, load, maximum aeleration and speed, should also be introdued. Leture 07 Classifiation by the Manipulator Struture In this leture the manipulators are lassified based on its first three joints. They fit into one of the following ategories: artesian, ylindrial, spherial (or polar), horizontal artiulation, SCARA, vertial artiulation and anthropomorphi. The workspae and harateristis of eah one should also be presented. The wrists used to orientate the end effetor should also be presented and lassified. Usually they have three joints with two possible onfigurations: pith-yaw-roll (yxz equal to the human wrist) or roll-pith-roll (zyz spherial wrist). The last one is more used due to be simpler, but it has singularities. In this leture, drawings, preferably in perspetive (three dimensions), should be used to failitate understanding. Leture 08 Atuators The main atuators responsible for the manipulators movements should be presented, inluding gears and oupling devies. Then, they an be lassified aording to the type of movement, plae of fore/torque appliation and type of drive (soure of energy: eletrial, hydrauli or pneumati). The appliations, advantages and disadvantages of the atuators should be disussed. Leture 09 Internal Sensors The robots must interat with more peripherals than the traditional industrial mahines, so the issues related to sensors are wider. It is suggested to divide it into two groups: internal sensors (propioeptives) and external sensors (exteroeptives), in two separated letures. At the first leture an introdution is done and the separation is made. Then, the main internal sensors are presented: enoders (relative and absolute), other position sensors, tahometers, sensors of fore/torque, et. They an be ategorized by the type of information provided and by the working priniple. Leture 10 External Sensors Similarly to the last leture, here the main external sensors used in roboti systems are presented: ameras, presene sensors, position sensors, et. Leture 11 End Effetors In this leture the end effetors are presented and lassified into two broad ategories: grip (for handling or manipulation) and tools (for general work or speifi appliation). Should be lear that, the robot does not ontrol only the position and orientation, but it an also ontrol the operation of the tool in the yle of work. These two ategories may be subdivided. The grips an be: fingered, magneti, vauum sution, hooks or adhesive. The main tools used with manipulators are: drills, spray pistols, welding point, ar welding torhes and utters by water jet and laser. The teaher should disuss the appliations of eah grip and toll and how to speify them. Leture 12 Types of Movements and Classifiation by Method of Control In this leture the robots are lassified aording to the method of ontrol used: servo-ontrolled or not. Firstly the point to point and ontinuous path movements must be presented. Then, the oordination of the joints movements (sequential, oordinated and unoordinated) and trajetory generation should be disussed. Finally, a brief introdution to the position ontrol of manipulators in open loop and losed loop should be provided. Leture 13 Appliations In this leture the main appliations of robot manipulators are presented, inluding: handling and transportation of materials, assembling and disassembling, spray painting, welding, soldering, utting, milling, drilling, lassifiation and inspetion of parts, et. The tehnial speifiations of the robots for eah task should be disussed. To illustrate, real robots atalogs (data sheets) of different models and from different manufaturers may be presented. Leture 14 Administrative and Eonomi Issues In this leture the automation should be disussed onsidering administrative and eonomi issues. The following topis may be presented: prodution volumes, osts (of materials, labor, robots and tools), investments, revenue, employment, et. Several types of industries an be analyzed, suh as: automotive, eletrial and eletronis, hemial, rubber and plastis, mahinery, metal produts, ommuniations, food, preision optis and others. A simplified analysis of osts omparing prodution lines with robots and without robots an be shown. The return on investment and benefits by using robots (produt quality, redution of aidents, labor osts, et.) should be disussed too.

4 Leture 15 Soial Issues In this leture the soial issues, mainly related to employment and its onsequenes, are presented. The myth of unemployment aused by industrial automation, in partiular by the robots, and proposal of alternatives for solving the problem should be disussed. Leture 16 Robotis in Brazil This leture is used to provide an overview of Robotis in Brazil. It is important for the students to know a little of the labor market and to see the reality of the siene in the ountry. Statistial data, as the number of robots installed per year (and omparison with other ountries/regions), the main industrial users, major suppliers, perentage by appliation area, et. should be presented. The main researh being undertaken (or ompleted) in Universities and training for skilled labor (eduational institutions and manufaturers, ourses offered, et.) may also be presented. Finally, eonomi and soial questions related to Brazil an be disussed. Leture 17 On-Line Programming The robots an be programmed in several ways. It is suggested to divide the topi programming into two groups: online (learning) and off-line (languages), in two separated letures. The first leture should be used for an introdution to the theme and to do the separation proposed above. After the introdution, the on-line programming, also alled programming by learning, should be presented. Either the mehanized programming, using a portable ontrol box to ontrol the joints, suh as manual traking step by step should be explored. The advantages and disadvantages of eah kind of programming may be disussed. Leture 18 Off-Line Programming Unlike the previous leture, here the robot manipulator is not need to perform the programming. The programming an be done by textual languages, similar to omputer programming, or by graphis programming environments. The main languages should be mentioned, but is suggested to use a fititious teahing language with the basi ommands. Finally, the advantages and disadvantages may be disussed, inluding with respet to programming on-line. Leture 19 Cellular Manufaturing The basis of physial arrangement (layout) for flexible manufaturing ells using robots should be provided in this leture. This is a very important leture, beause several topis disussed in the previous letures as onepts, sensors, end effetors and programming, are grouped and used here. Leture 20 Pratie on Manufaturing Cell - I To fix the issue and enourage the reativity of students, in this leture is offered one exerise to projet a manufaturing ell with, at minimum, two robot manipulators. It is appropriate to do the exerise in groups or in pairs. The proposed problem may be the same for the entire lass or different for eah group, aording to the proposition. Leture 21 Pratie on Manufaturing Cell - II This leture is a ontinuation of the previous one. The final time of the leture is reserved to disuss the results. This leture loses the first part of the ourse. Thus, at this time the groups and themes for the seminars may be defined, whih shall inlude but not to be limited on the letures already done. Leture 22 Geometry The Kinematis is a fundamental tool in the design and ontrol of manipulators. For the kinemati modeling it is neessary a good knowledge of Geometry. However, the Geometry is taught in the first years of undergraduate programs. Therefore, a revision is neessary. It is important to fous the matter on the manipulators and to standardize the notation, as shown in Fig. 1, one it will be used from now to the end of the ourse. α i θ i θ i Figure 1 Position and Orientation of a Rigid Body Figure 2 Denavit-Hartenberg Notation The manipulator an be modeled as a system of rigid bodies (that are the links). Thus, in this leture the geometry and movement of rigid bodies, onsidering the position and orientation, are approahed. Transformations of oordinates and rotations of vetors are reviewed. As notation, a position vetor 3 1 d and a rotation matrix 3 3 R may be used. At the end of the leture the three different physial meanings of the rotation matrix R should be explored and disussed.

5 Leture 23 Euler Angles In this leture are present and define the three angles φ, θ and ψ, alled Euler angles, that uniquely determine the orientation of a oordinated system. Should be shown how to set up the rotation matrix R, that represents the three onseutive rotations assoiated with the Euler angles. The notation R ), whih means a rotation of an angle θ around the axis e onsidering the right hand rule, may be used. Leture 24 Homogeneous Transformations and Diret Kinematis Equation At the beginning of this leture the homogeneous transformation is presented. Using the position vetors, as shown at left of Eq. (1), and de rotation matrix R, the matrix form of the homogeneous transformation is obtained. e(θ x p y P = = 1 z 1 p = x y = z 1 P P = AP 1 x y = z 1 R 0 x d y z 1 1 (1) i 1 It is important to larify that this equation an be used for onseutive transformations. Using matries A i that transform from the system i to the system i 1, the position vetor P n in the system n an be transformed to P 0 in the system 0 by: P n 1 n = A1 A2L A n P. At the end, should be shown how the homogeneous transformations an be used to desribe the position and orientation of eah link of an open kinemati hain (manipulator). Denoting the displaement of the joints by q i, where: qi = θi for rotation joint and q i = di for prismati joint, the diret kinemati matrix is obtained. As example, a planar manipulator of two degrees of freedom may be modeled. Leture 25 Convention for Representation In this leture the Denavit-Hartenberg notation, based on 4 4 matrix representation of position and orientation of rigid bodies, should be introdued. The benefits, how to identify the parameters and the exeptions should be presented. Using a piture as shown in Fig. 2, it is easier to identify the parameters: - d i and α i, orresponding to the translation and the rotation of the joint i on the z axis of the joint i-1, respetively; - a i and θ i, orresponding to the translation and the rotation of the joint i+1 on the x axis of the joint i, respetively. To express the transformation of oordinates between the systems i and i-1 is advised to use an auxiliary system. It is important to disuss the results from the mathematial point of view, for example, notiing that the transformation of the system i to the system i-1 is a funtion only of the variable of the joint i. Leture 26 Examples of Kinemati Modeling In this leture examples of kinemati modeling are made. It is suggested to model, at minimum, a planar manipulator of two degrees of freedom, a spherial manipulator and a wrist. Leture 27 Inverse Kinematis This leture introdues the inverse Kinematis. The goal is to find the displaements of the joints whih drive the end effetor to a speified position and orientation. Firstly, an analytial solution should be used. To alulate the inverse position the geometri approah is used. To alulate the orientation should be explored the kinemati deoupling of the spherial wrist. The planar manipulator also may be used as example. The higher omplexity of the inverse Kinematis problem, ompared to the diret Kinematis, and the possibility of multiple solutions or no solution should be disussed. The Engineering onsiderations for the existene of solution should be presented too. An alternative to the analytial solution, the numerial, may be proposed. Leture 28 Differential Inverse Kinematis In many appliations beyond the position of the end effetor its speed is also important. This involves oordinating the joints movements. In this leture the relationship of the end effetor s speed and joints speed will be onsidered using the differential or instantaneous inverse Kinematis. The manipulator s Jaobian matrix should be introdued, showing its harateristis and desribing how it may be used. It is important to larify that the Jaobian matrix is given in terms of the joints displaements and, therefore, varies with the onfiguration of the manipulator. Leture 29 Introdution to Dynami Modeling In this leture a brief introdution to dynami modeling of robot manipulators is provided. The Newton-Euler and Lagrange approahes should be presented, in a superfiial way. It is important to make lear that the dynami behavior of the robot manipulator is omplex, sine there are several inputs and it is highly oupled and nonlinear.

6 Leture 30 Seminar - I In this meeting the seminars are presented. The presentation should be preferably publi, inviting students from other years and lasses. Thus, the work of the students is valued and the interest of other students by the Robotis may be attrated. The time for eah group may be 30 minutes (20 for presentation and 10 for disussion). Leture 31 Seminar - II This meeting is used for the presentations of seminars too. Leture 32 Final Examination In the last leture of the ourse a written test is applied. The subjet is the seond part of the ourse. 4. BIBLIOGRAPHY OF THE COURSE Considering the proposal of this artile, there is not a single book that overs the entire ontent of the ourse. Therefore, a basi book that has most of the subjet is hosen as textbook and other books, artiles and texts are used as supplements. Currently the textbook of the ourse is (Romano, 2002). As supplementary literature, espeially for the seond part of the ourse, may be adopted one of the following books: (Asada and Slotine, 1986), (Craig, 2004), (Siavio, 1995), (Spong and Vidyasagar, 1989) or (Yoshikawa, 1990). Eah one overs all the neessary material. To aid in the ontrol subjet the book (Ogata, 2003) is used. 5. GRADING The grading is done through one seminar, one test and exerises (homework). The purpose of the seminar is to make the students explore the topis presented in the letures of the first part of the ourse and to be aware of newly developing tehnologies in Robotis. Besides, after the seminar the students will be able to searh, read, understand and evaluate new literature about Robotis. It will improve the students abilities for lifelong learning and professional refletion. The grade of the seminar is 40%. The final exam is written, individually and without onsultation (losed book), onerning mainly the seond part of the ourse. The grade is 40%. During the ourse individual exerises are done, to be given to the teaher. The grade is 20%. 6. CONCLUSION This paper desribes a multidisiplinary introdutory ourse on industrial Robotis. In the first part of the ourse, history, onepts, lassifiations, programming and Prodution, Administrative, Eonomis and Soial issues are taught. In the seond part, the fous is the modeling of manipulators. During the ourse the students are required to pratie. The ourse is omplemented with elaboration of seminars, whih also greatly ontributes to the good results. The ourse provides solid theoretial foundations to analysis of industrial roboti systems. After ompleting this ourse, the students are able to start working with industrial manipulators, understanding their funtions and limitations. The proposed topis and methodology have proven to be useful. However, the proposal presented here is a base line, therefore, hanges aording to the teaher s assessment an be made. Besides, some topis ould be inluded, exluded or improved. 7. REFERENCES Asada, H. and Slotine, J.-J., Robot Analysis and Control, Ed. John Wiley Professional, New York, USA, 288 p. Craig, J.J., Introdution to Robotis, Ed. Pearson Prentie Hall, New York, USA, 408 p. Guizzo, E., deember The Rise of the Mahines, IEEE SPECTRUM Magazine, pp. 60, USA. Ogata, K., Engenharia de Controle Moderno, Ed. Pearson Eduation, São Paulo, Brazil, 800 p. Rafael, Y.R., Eduação Integral: Uma Eduação Holístia para o Séulo XXI, Ed. Artmed, São Paulo, Brasil, 270 p. Romano, V.F., Robótia Industrial: Apliação na Indústria de Manufatura e de Proessos, Ed. Edgard Blüher, São Paulo, Brasil, 280 p. Salvador, C.C., Construtivismo na Sala de Aula, Ed. Átia, São Paulo, Brazil, 224 p. Siavio, L., Modeling and Control of Robot Manipulators, Ed. MGraw Hill, New York, USA, 377 p. Spong, M.W. and Vidyasagar, M., Robot Dynamis and Control, Ed. John Willey, New York, USA, 352 p. Yoshikawa, T., 1990, Foundations of Robotis Analysis and Control, Ed. MIT Press, New York, USA, 297 p. 8. RESPONSIBILITY NOTICE The author is the only responsible for the printed material inluded in this paper.