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Off-line programming of industrial robots
116
ConferenceReports
Off-Line Programming of Industrial Robots The Proceedings of the IFIPWG 5.3/IFAC Working Conference on Off-Line Programming was held in Stuttgart, F.R.G. from 2-3 June 1986. In the preface to the published proceedings, J.P. Crestin, Chairman of IFIP WG 5.3, explained that IFIP Working Conferences aim at presenting the state of the art in a given domain and at discussing its future developments. With only invited participants they gather world known specialists. Working Group 5.3 "Discrete Manufacturing" covered all aspects of Computer Aided Manufacturing. It holds triennial meetings, the PROLAMAT conferences, which cover recent developments in the whole field of CAM. Robots are now increasingly used in industry for machining and assembly, in large firms (automotive, aerospace, naval industry...), but also recently more and more in small and medium size firms. Robots programming is now clearly the bottleneck of robots use in many industrial applications. Different approaches, teach-in methods, simulation, dedicated programming languages, use of expert systems and artificial intelligence methods, are being tried. Off-line programming, covering a large part of these methods, is certainly the key to a better efficiency of robots use. Crestin explained that now was the time to compare different methods and experiments in order to give guidelines for future developments and for industrial use. Stuttgart, with its world known research laboratories in CAM and robotics and its largely automatised automotive industry was certainly one of the best places in the world to organise such a conference. We present below a report on the lectures delivered at the conference.
Opening Lecture
tions are necessarily fixed by the programming methods. The motion and order of execution is, in general, described in the program in order to solve the problem. The different methods were explained and evaluated. A. Storr and 11. Schureacher (University of Stuttgart, Stuttgart, F.R.G.) explained that during this conference off-line programming will be in the foreground. They stated that the fundamental objective of a working conference is to present and discuss solutions, or partial solutions, as well as the trends of future development and presented the important development areas: the definition of interfaces; the analysis and consideration of the technical demands on manufacturing and assembly processes taking into account sensor data; programming aids, and the integration of robot programming in the field of CIM.
Off-line Programming - Where are we?
Off-Line Programming The development of industrial robots (m) in the Federal Republic of Germany was considered in the presentation by W. Pollman and H. Dzembritzki (Daimler-Benz Aktiengesellschaft Werk Sindelfingen, Verfahrensentwicklung, F.R.G.). They went on to describe the development phases of a specific IR application: the selection of a suitable industrial robot; the design of the handling device; the position sensing; the peripheral equipment, and the availability. On- and off-line programming were then considered with the decisive reasons for off-fine programming given as: time saving; exact planning; quality gain and humanisation. Off-fine programming was then analysed in more detail.
Programming Methods Comprehensive Modelling The installation of industrial robots in manufacturing and assembly has dramatically increased. The solutions to the problems of machining, joining and handling are distinctly different. In the case of small and medium batch sizes, the flexibility and productivity of the robot installa-
In order to achieve high flexibility and productivity using industrial robots, it is important to have a good off-line programming system. For ease of programming, it is vital to realise a comprehensive modelling capability for machine prod-
ConferenceRepor~ ucts to be manipulated and also working environments and robots. T. Sata, F. Kimura, H. Hiraoka, H. Suzuki and T. Fujita (University of Tokyo, Tokyo, Japan) proposed a powerful modelling framework which was originally developed for product modelling in CAD/CAM, and showed its application to fine motion generation in off-line robot programming for machine assembly. They explained that fine motion generation can be carried out automatically based on geometric reasoning about geometric constraints in machine assembly models. Some experimental results were also given.
Programming Strategies
117
adapt sensors and to generate technological data are to be created.
Assembly Application A Dedicated Language In the field of manufacturing planning linguistic means have been developed to allow models of assembly tasks to be developed descriptively. J. Loetzsch and J. v. Pistor (University of Dresden, Dresden, G.D.R.) described the SAT (Special Assembly Tasks) experimental system which enables the use of such problem-oriented linguistic means for automatic off-line programming of an assembly cell. It can be used directly by the manufacturing engineer.
An Interactive Model Task-Oriented Programming The current robot programming technology does not focus the demands for the next generation of intelligent sensor guided robots and flexible automation for small batch production. M. Weck, Th. Niehaus and M. Osterwinter (Technical University of Aachen, Aachen, F.R.G.) described that by moving towards an efficient integrated robot programming environment, an interactive off-line programming and simulation workstation has been developed at the Machine Tool Laboratory (WZL) at Aachen. They focused on the system concept, implementation and application aspects.
For programming a flexible assembly system for wiring harnesses the IPA-Stuttgart developed a task oriented off-line-programming system. H.-J. Warnecke, A. Altenhein, M. GShner and G. Schlaich (Fraunhofer Gesellschaft, Stuttgart, F.R.G.) described the problems of realising the whole system with the steps generating the task description, reducing it to a frame concept, compiling to an industrial robot program, transferring the program to a standard industrial robot and the problems of differences between the off-line-programmed positions and the real positions.
Geometrical Data Recording
Complex Compliant Modes
G. Pritschow, A. Storr, G. Gruhler and H. Schumacher (University of Stuttgart, Stuttgart, F.R.G.) described the problems impeding the implementation of off-line programming and explained how to avoid some of them. They presented a programming system that allows explicit programming of industrial robots using the problem-orientated robot programming language BAPS. This programming system can be run both as part of the robot control and on an external programming computer. It uses the IgDAa'Ainterface, being standardised at present, for the transfer of control data between the programming system and robot control. They explained that further developments of the language Bxps are aimed at creating a homogeneous programming language for the complete robot cell. In addition, language elements to
The use of a manipulator-gripper to achieve complex assembly tasks was described by P. Bidaua~ J.C. Guinot, F. Boudin, A. Bernardy and D. Fontaine (University of P. and M. Curie, Paris, France). They explained that for future experiments, different situations are now under investigation to correct small variations in relative position or orientation of assembly parts. They described how they must be expressed as control problems.
Simulation Collision Detection Collision detection techniques are necessary if efficient off-line programming of robots is to be
118
ConferenceRepor~
achieved. R.K. Stobart (Cambridge Consultants Ltd, Cambridge, U.K.) described techniques developed for use with the BUILt) solid modeller. He reported that basic collision detection facilities have been improved to give increased accuracy and an efficient means of monitoring minimum distance trends. A Graphic Simulator S.A. Langrudi (Graham Architectural Products, York, PA, U.S.A.) and J.B. Ochs (Lehigh University, Bethlehem, PA, U.S.A.) described VALSIM.LU, a Graphic Simulator of the Off-line Programming Language VAL-IL They explained that in addition to its fundamental programming and control features VAL-H also includes a network communication capability which enables a remote computer to totally supervise the operation of robot systems, computational facilities like those found in highlevel computer languages, a general interface for sensory information, real-time path control and concurrent process control. VALSIM.LUwas designed in order to aid students in learning the fundamentals of robot motion and off-line programming,
Programming Aids Colour Graphics Technique
The complex/model presented by A. Klein (Hungarian Aca~lemy of Sciences, Budapest, Hungary) consisted of three main parts: tools for building and drawing workpieces to be painted; the model of the robot; the mathematical model of the spatial distribution of the paint particles. LOLA
A research project was presented by L. oan Aken, H. van Brussel, J. De Schutter, P. Simkens and F. De Meester (The Catholic University of Leuven, Leuven, Belgium) dealing with the design of an explicit off-line programming system, as an
intermediate step to a more abstract implicit programming system. Frames are used as manipulation variables. However, the system is supported by a world model, the structuring capabilities of which enable the user to reason in terms of the manipulation of objects. They explained that the task-level system will derive this database from a more comprehensive geometrical caD-database. A general compliant motion strategy, based on force sensor inputs, is incorporated into the programming system. A generalisation to other sensor types is also provided. Finally they described how graphical simulation of programmed tasks is provided as a means of verification.
Programming Towards the CIM Environment The Grasp Robot Simulation System M . C Bonney, R.J. Marshall and J.L. Green (BYG Systems Ltd, Nottingham, U.K.) described the advantages of off-line programming which indudes the generation of positional coordinate data. They went on to describe GRASP, a graphical robot simulation system containing a 3D solid geometric modeller and a generalised kinematic robot modeller. They explained how to create the robot program and gave an example to illustrate the programming techniques used in ~RAsP.
An Integrated Approach
Optimal solutions for task programming problems of industrial robots can be achieved using integrated off-line programming system architecture. The main aspects of this architecture such as interfaces, integration of different models and simulation were discussed by G. Spur, G. Duelen and F.-L. Krause (Fraunhofer Institute, Berlin, F.R.G.) using concrete examples. The proceedings of the conference will be published by North Holland, P.O. Box 1991, 1000 BZ Amsterdam, The Netherlands.
ConferenceReports
Off-Line Programming of Industrial Robots The Proceedings of the IFIPWG 5.3/IFAC Working Conference on Off-Line Programming was held in Stuttgart, F.R.G. from 2-3 June 1986. In the preface to the published proceedings, J.P. Crestin, Chairman of IFIP WG 5.3, explained that IFIP Working Conferences aim at presenting the state of the art in a given domain and at discussing its future developments. With only invited participants they gather world known specialists. Working Group 5.3 "Discrete Manufacturing" covered all aspects of Computer Aided Manufacturing. It holds triennial meetings, the PROLAMAT conferences, which cover recent developments in the whole field of CAM. Robots are now increasingly used in industry for machining and assembly, in large firms (automotive, aerospace, naval industry...), but also recently more and more in small and medium size firms. Robots programming is now clearly the bottleneck of robots use in many industrial applications. Different approaches, teach-in methods, simulation, dedicated programming languages, use of expert systems and artificial intelligence methods, are being tried. Off-line programming, covering a large part of these methods, is certainly the key to a better efficiency of robots use. Crestin explained that now was the time to compare different methods and experiments in order to give guidelines for future developments and for industrial use. Stuttgart, with its world known research laboratories in CAM and robotics and its largely automatised automotive industry was certainly one of the best places in the world to organise such a conference. We present below a report on the lectures delivered at the conference.
Opening Lecture
tions are necessarily fixed by the programming methods. The motion and order of execution is, in general, described in the program in order to solve the problem. The different methods were explained and evaluated. A. Storr and 11. Schureacher (University of Stuttgart, Stuttgart, F.R.G.) explained that during this conference off-line programming will be in the foreground. They stated that the fundamental objective of a working conference is to present and discuss solutions, or partial solutions, as well as the trends of future development and presented the important development areas: the definition of interfaces; the analysis and consideration of the technical demands on manufacturing and assembly processes taking into account sensor data; programming aids, and the integration of robot programming in the field of CIM.
Off-line Programming - Where are we?
Off-Line Programming The development of industrial robots (m) in the Federal Republic of Germany was considered in the presentation by W. Pollman and H. Dzembritzki (Daimler-Benz Aktiengesellschaft Werk Sindelfingen, Verfahrensentwicklung, F.R.G.). They went on to describe the development phases of a specific IR application: the selection of a suitable industrial robot; the design of the handling device; the position sensing; the peripheral equipment, and the availability. On- and off-line programming were then considered with the decisive reasons for off-fine programming given as: time saving; exact planning; quality gain and humanisation. Off-fine programming was then analysed in more detail.
Programming Methods Comprehensive Modelling The installation of industrial robots in manufacturing and assembly has dramatically increased. The solutions to the problems of machining, joining and handling are distinctly different. In the case of small and medium batch sizes, the flexibility and productivity of the robot installa-
In order to achieve high flexibility and productivity using industrial robots, it is important to have a good off-line programming system. For ease of programming, it is vital to realise a comprehensive modelling capability for machine prod-
ConferenceRepor~ ucts to be manipulated and also working environments and robots. T. Sata, F. Kimura, H. Hiraoka, H. Suzuki and T. Fujita (University of Tokyo, Tokyo, Japan) proposed a powerful modelling framework which was originally developed for product modelling in CAD/CAM, and showed its application to fine motion generation in off-line robot programming for machine assembly. They explained that fine motion generation can be carried out automatically based on geometric reasoning about geometric constraints in machine assembly models. Some experimental results were also given.
Programming Strategies
117
adapt sensors and to generate technological data are to be created.
Assembly Application A Dedicated Language In the field of manufacturing planning linguistic means have been developed to allow models of assembly tasks to be developed descriptively. J. Loetzsch and J. v. Pistor (University of Dresden, Dresden, G.D.R.) described the SAT (Special Assembly Tasks) experimental system which enables the use of such problem-oriented linguistic means for automatic off-line programming of an assembly cell. It can be used directly by the manufacturing engineer.
An Interactive Model Task-Oriented Programming The current robot programming technology does not focus the demands for the next generation of intelligent sensor guided robots and flexible automation for small batch production. M. Weck, Th. Niehaus and M. Osterwinter (Technical University of Aachen, Aachen, F.R.G.) described that by moving towards an efficient integrated robot programming environment, an interactive off-line programming and simulation workstation has been developed at the Machine Tool Laboratory (WZL) at Aachen. They focused on the system concept, implementation and application aspects.
For programming a flexible assembly system for wiring harnesses the IPA-Stuttgart developed a task oriented off-line-programming system. H.-J. Warnecke, A. Altenhein, M. GShner and G. Schlaich (Fraunhofer Gesellschaft, Stuttgart, F.R.G.) described the problems of realising the whole system with the steps generating the task description, reducing it to a frame concept, compiling to an industrial robot program, transferring the program to a standard industrial robot and the problems of differences between the off-line-programmed positions and the real positions.
Geometrical Data Recording
Complex Compliant Modes
G. Pritschow, A. Storr, G. Gruhler and H. Schumacher (University of Stuttgart, Stuttgart, F.R.G.) described the problems impeding the implementation of off-line programming and explained how to avoid some of them. They presented a programming system that allows explicit programming of industrial robots using the problem-orientated robot programming language BAPS. This programming system can be run both as part of the robot control and on an external programming computer. It uses the IgDAa'Ainterface, being standardised at present, for the transfer of control data between the programming system and robot control. They explained that further developments of the language Bxps are aimed at creating a homogeneous programming language for the complete robot cell. In addition, language elements to
The use of a manipulator-gripper to achieve complex assembly tasks was described by P. Bidaua~ J.C. Guinot, F. Boudin, A. Bernardy and D. Fontaine (University of P. and M. Curie, Paris, France). They explained that for future experiments, different situations are now under investigation to correct small variations in relative position or orientation of assembly parts. They described how they must be expressed as control problems.
Simulation Collision Detection Collision detection techniques are necessary if efficient off-line programming of robots is to be
118
ConferenceRepor~
achieved. R.K. Stobart (Cambridge Consultants Ltd, Cambridge, U.K.) described techniques developed for use with the BUILt) solid modeller. He reported that basic collision detection facilities have been improved to give increased accuracy and an efficient means of monitoring minimum distance trends. A Graphic Simulator S.A. Langrudi (Graham Architectural Products, York, PA, U.S.A.) and J.B. Ochs (Lehigh University, Bethlehem, PA, U.S.A.) described VALSIM.LU, a Graphic Simulator of the Off-line Programming Language VAL-IL They explained that in addition to its fundamental programming and control features VAL-H also includes a network communication capability which enables a remote computer to totally supervise the operation of robot systems, computational facilities like those found in highlevel computer languages, a general interface for sensory information, real-time path control and concurrent process control. VALSIM.LUwas designed in order to aid students in learning the fundamentals of robot motion and off-line programming,
Programming Aids Colour Graphics Technique
The complex/model presented by A. Klein (Hungarian Aca~lemy of Sciences, Budapest, Hungary) consisted of three main parts: tools for building and drawing workpieces to be painted; the model of the robot; the mathematical model of the spatial distribution of the paint particles. LOLA
A research project was presented by L. oan Aken, H. van Brussel, J. De Schutter, P. Simkens and F. De Meester (The Catholic University of Leuven, Leuven, Belgium) dealing with the design of an explicit off-line programming system, as an
intermediate step to a more abstract implicit programming system. Frames are used as manipulation variables. However, the system is supported by a world model, the structuring capabilities of which enable the user to reason in terms of the manipulation of objects. They explained that the task-level system will derive this database from a more comprehensive geometrical caD-database. A general compliant motion strategy, based on force sensor inputs, is incorporated into the programming system. A generalisation to other sensor types is also provided. Finally they described how graphical simulation of programmed tasks is provided as a means of verification.
Programming Towards the CIM Environment The Grasp Robot Simulation System M . C Bonney, R.J. Marshall and J.L. Green (BYG Systems Ltd, Nottingham, U.K.) described the advantages of off-line programming which indudes the generation of positional coordinate data. They went on to describe GRASP, a graphical robot simulation system containing a 3D solid geometric modeller and a generalised kinematic robot modeller. They explained how to create the robot program and gave an example to illustrate the programming techniques used in ~RAsP.
An Integrated Approach
Optimal solutions for task programming problems of industrial robots can be achieved using integrated off-line programming system architecture. The main aspects of this architecture such as interfaces, integration of different models and simulation were discussed by G. Spur, G. Duelen and F.-L. Krause (Fraunhofer Institute, Berlin, F.R.G.) using concrete examples. The proceedings of the conference will be published by North Holland, P.O. Box 1991, 1000 BZ Amsterdam, The Netherlands.