VIRTUAL PLANT
Planning in the virtual production system
To comply with increasing levels of competition industrial companies use flexible automated integrated production systems more and more. Programmable machines such as robots, cnc-machines and plc's are a natural part of any automated production system (Computer Integrated Manufacturing and Engineering system, CIME).
Optimal utilization of flexible CIME systems requires fast rearrangements and optimized programs. Ropsim is a tool for planning in the virtual production system. Ropsim is a model driven simulation tool with 3D visualization. The time used for rearrangements is reduced to the time it takes to download and in some cases calibrate the programs for the equipment.
© E.Trostmann 1988. Off-line programming.
Production planning in the virtual production system is carried out through model driven simulation. The most significant installations of the production system are described with models and through simulation their properties are visualized. Different combinations of equipment, layouts, programs, product designs, and the interplay of these items are tested and evaluated in simulation.
Ropsim offers the following opportunities through planning in the virtual production system:
- Minimizing rearrangement hours through simulation and off-line programming
- Optimizing existing programs
- Reuse of existing CAD data
- Testing of new equipment in the production system before investments are made
- Visualizing the virtual system in 3D computer graphics
Simulation
The simulation is performed with basis in the models. The simulation is visualized in real time 3D graphics. The virtual production system and the models are evaluated on the basis of the simulation results. The models can be optimized through the modelling interface. After the achievement of an appropriate quality has been reached the programs are downloaded to the production system.
In Ropsim experiments can be performed in the virtual production system. Experiments can support a variety of different analyses focusing on criterias such as: equipment layout, production capacity, cycle time, and rearrangement costs.
Ropsim provides very exact dynamic simulations. A well calibrated model can come close to 100% correspondence with the actual workcell.
Robot Models
Ropsim uses a generic robot model that every piece of production equipment can be modelled after. Every model in Ropsim can be described by one or more of the robot model's three model parts: a program, a controller model, and a manipulator model.
- The manipulator model consists of a 3D solid model, a kinematisk og model.
- The controller model contains a model of the robot controller.
- The program specifies the task that the machine shall perform.
Production equipment such as robots, CNC-machines, fixtures, conveyors, etc, can all be modelled in the robot model. Communication lines in the production system are modelled as corresponding connections between the models.
Model sources
Off-line programming is based on models of the workcell. These are models of the robot, pieces and the surroundings. The models can be built in many different ways:
Model interchange
Ropsim is designed as a component of an integrated production system, where every piece of information (for instance CAD-models, robot programs) in interchanged between the systems. The STEP standard is supported for interchange of CAD/CAM models.
Model library
Ropsim's model library contains robots, CNC-machines, fixtures, conveyors etc. The models are imported from the library and used in the simulation.
User built models
User created models are formed through the graphical user interface. Manipulator models are built out of 3D solid models, kinematic and dynamic models. For the controller models the parameterized generic motion controller is used. The programs are written in the robot program language IRL (Industrial Robot Language, DIN standard), a Pascal based language.
Ropsim's basic object oriented design implies a large measure of openness for user built additions. Through inheritance of the generic robot model user additions can be introduced form C++. The object oriented design provides a very open development environment where users easily can build specialized applications. The system is likewise open for development of third party plug-in's.