Industrial Robot Programming Nilsson, Klas 1996 Document Version: Publisher's PDF, also known as Version of record Link to publication Citation for published version (APA): Nilsson, K. (1996). Industrial Robot Programming. Department of Automatic Control, Lund Institute of Technology (LTH). 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LUND UNIVERSITY PO Box 117 221 00 Lund +46 46-222 00 00 Preface Preface Machines that perform hard or boring work have interested me ever since I was a boy and had to help my parents on our farm. I was more interested in mathematics physics, and machines. During the end -70’s, I got acquainted with computers and control. That opened a new and very interesting world for me. When I finished my studies for a master’s degree in mechanical engineering, I was still very interested in helpful (intelligent) machines. It was therefore an easy choice where to apply for a job: ASEA Robotics. When I came to ASEA (later ABB) in 1982, Robotics was a new and progressive division which was managed more like a small company. At that time, the demands on profitability were not severe. The primary goal was to make good robot systems. Market share and company size therefore grew rapidly. For me it was six years of stimulating control engineering together with very good friends/colleagues. The control engineering work ranged from tuning of joint servos to overall system design. When more than thousand, instead of a few hundreds, of robots were manufactured, profitability and cost efficiency for present major applications were getting increasingly important. That was of course a correct policy, but customers with good but unforeseen ideas about how to use robots, too often could not accomplish the control. To start with I was most interested in feedback control theory, but later it became clear to me that the structure of the control system was of key importance for the development of intelligent machines. Published research results were, however, not quite useful because important industrial aspects were overlooked. To do research in this direction, we moved back to Lund where I got the opportunity to do a PhD at the Department of Automatic Control. Research within automatic control almost always treats well defined problems well suited for formal methods. It has therefore not been easy to tackle a problem that does not fit into this pattern. I hope control re- searchers do not get too disappointed when they do not find their favorite equations in this thesis. My work has been problem oriented. The subject and the developed solutions are closely related to computer science and production engineering, but the interplay between robot programming and feedback control is of key importance. It is now a great pleasure for me to complete this thesis, and I very much hope that ideas presented here will contribute to systems that better can perform work that is unfriendly to humans. vii Preface Acknowledgments This work was carried out in a friendly and inspiring atmosphere at the Department of Automatic Control in Lund, Sweden. Professor Karl Johan Åström has been a constant source of inspiration and information. It is mainly due to him that I have had the opportunity to work in a research environment where one can get support and advice when needed, but also freedom to continue along my own ideas (even at times when nothing seems to work). I am also grateful to all other people at the department. Without mentioning all names, this includes professors, technical staff, our charming and helpful secretaries, PhD student friends, and master thesis students that I have been guiding. During the first stage of my work (until my licentiate thesis was completed), Lars Nielsen was my closest supervisor. He helped me turn my ideas into problems definitions and solutions, and he encouraged me to pursue this direction of research. He and Ola Dahl were very helpful and it was a pleasure to work with them. Rolf Johansson has given me invaluable guidance during the final part of my work. We have also applied for funds and managed robot research projects together. I really appreciate his comments on this thesis, and I hope we can collaborate somehow also in the future. Thanks also to Björn Wittenmark and Karl-Erik Årzén for valuable comment on the manuscript. The hardware interfaces to our ABB Robots were built by Rolf Braun, who also made the detailed design according to my (coarse) descriptions. I do not know the number of weeks we put into this, but I am very grateful for all his help. Many thanks also to Anders Robertsson forhiseffortsintherobotlab. The financial support from NUTEK, which made this work and the development of the experimental platform possible, is gratefully acknowl- edged. I am also grateful for support and comments from my colleagues at ABB Robotics. The ABB/LTH robot interface could hardly have been developed without the access to information within ABB. Among others, Håkan Brantmark, Torgny Brogårdh, Peter Eriksson, Anders Holmer, Åke Madesäter, Mats Myhr, Einar Myklebust, Ulf-Göran Norefors, Ingemar Reyier, Lars Östlund, and all my friends within the Motion Control Group have helped me to keep in touch with the industrial reality. It has been nice to use our properly working computer system man- aged by Leif Andersson, who is always helpful and interested in arranging things for the user’s best. The real-time kernel and communication soft- ware I have been using is mainly due to Anders Blomdell. He has also been a great source of information concerning practical aspects of soft- ware design and hardware-related programming. He also convinced me viii Preface that his implementation of dynamically linked actions (Chapter 7) usually is more appropriate than the function-based solution that I made. Present and former members of the CACE project has also given valuable hints about software. This includes Dag Brück who often helped me to to use and misuse C++. Contributions from the guest researchers Albert-Jan Baerveldt and Marcel Schoppers have also been helpful. Due to the multidisciplinary topic of robot control and programming, interaction with other departments here in Lund has been of great value. At the Department of Production and Materials Engineering, Gunnar Bolmsjö, Krister Brink, Per Hedenborn, Hamid Nasri, Georgio Nicoleris, Magnus Olsson, and Björn Ågren have given valuable comments. Some of these persons also gave me access to the robot programming system IGRIP. At the Department of Computer Science, I have had the pleasure to interact with Elizabeth Bjarnason, Görel Hedin, Roger Henriksson, and Boris Magnusson. Their comments about object-oriented software, and their efforts put into the Applab system, have been valuable both for development of principles and for prototyping language aspects of robot programming. The always enthusiastic Gustaf Olsson, head of the Department of Industrial Electrical Engineering and Automation, has also been a source of information. At that department, an interesting development of ultra- sonic sensing for industrial robots is made by Gunnar Lindstedt, who also programmed the some of the circuits in the robot interface. Our aim to utilize his ultrasonic system for robot control appears to be promising. The computer vision group at the Department of Mathematics, cur- rently including the researchers Anders Heyden, Gunnar Sparr, and Kalle Åström, has contributed with some vision facilities within our laboratory. I look forward to connecting new vision algorithms to improve the abilities of our (currently blind) robots. Finally, with some bad conscience for all evenings and weekends that have been spent at work, I want to thank my beloved wife Rosel and our lovely children for their love, patience and support. About the thesis Chapter 1 of this thesis contains a short introduction in general terms. Chapter 2 is also introductory, but it gives a broader manufacturing sys- tems perspective as well as a more specific description of the authors view of the problems. Conclusions are given in Chapter 9, whereas Chapters 3 to 8 present the contributions which also have been published according to next page. ix Preface The software architecture proposed in Chapter 4 and two of the application examples presented in Chapter 8 have been presented in K. NILSSON AND L. NIELSEN. “An architecture for application ori- ented robot programming.” In IEEE International Conference on Robotics and Automation, Nice, France, 1992. Part of Chapter 5 treats software techniques for special purpose hardware. This was presented in K. NILSSON. “Object oriented DSP programming.” In Proceedings of The Fourth International Conference on Signal Processing Ap- plications & Technology, DSP Associates, Santa Clara, CA, 1993. which was judged as one of the best papers, and therefore also published in a condensed form in K. NILSSON. “DSPs moving up to object-oriented programs.” Elec- tronic Engineering Times, September, 1993. Real-time and control aspects of such hardware are also mentioned in Chapter 5 and presented in K.