Integration of simulation and emulation with graphical design for the development of cell control programs

SUMMARY

A major problem in conventional and virtual manufacturing has been the lack of integrated tools for the off-line development and testing of cell control programs. Control device programs are typically created and evaluated using stand-alone computer simulations or actual production hardware. In contrast, graphic simulation/emulation workstations have provided a powerful virtual environment for robotic cell layout, device selection, path planning, programming, and testing. The resulting off-line task programs may then be translated to native robot languages and downloaded to production hardware. In this research, methods and functions have been introduced to permit modelling of cell control programs on the same graphical design platform, integrating logical and physical design. The control models are structurally and logically equivalent to device programs, allowing designers to use common information for control development and testing. Furthermore, the interactions of cell control with other design aspects may be observed and evaluated. This paper describes the integrated capability and an emulation model for a programmable logic controller, along with a method to graphically represent changes in control signal values in the simulation. Peripheral device models have been included to provide a library of parameterized object programs, simplify cell construction, and standardize cell emulation. The functions have been implemented and analysed in a case study using a generic task description language on a simulation/emulation workstation.

Additional information

Notes on contributors

S. Y. NOF

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