University of Twente Student Theses


Design and testing of embedded control software for the ViewCorrect Plotter

Kooistra, Cornelis (2007) Design and testing of embedded control software for the ViewCorrect Plotter.

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Abstract:For the ViewCorrect project, an x-y plotter is built. This is a research setup for testing concurrent real-time software. The context of the ViewCorrect project is to bring different disciplines, involved in a mechatronic system project, in a structured way together and therefore making the traditional gap between them smaller. One way of bringing different disciplines together is co-simulation. This project has researched the possibilities to co-simulate the CT-based plotter software written in gCSP with the 20-sim model that describes the behaviour of the ViewCorrect Plotter setup. The existing model of the ViewCorrect Plotter setup has been adjusted and validated. The difference between simulated and measured model is less than five percent. Next a 3D animation model and controllers have been designed. The controllers are capable of controlling the position of the pen. The plotter software has been made in gCSP. A workflow is presented which allows the user to make a drawing in a CAD drawing package and plot this drawing with the plotter. The controllers, designed in 20-Sim, and the safety layer are embedded in the plotter software. Co-simulation has been analysed in the scope of heterogeneous system design. A flexible framework is designed to handle the requirements for and challenges related to co-simulation. This framework has been evaluated in a case study. In this case study, the plotter software is tested together with the model that describes the behaviour of the plant and the I/O of the ViewCorrect Plotter setup. Co-simulation is a powerful tool for verification in a model-driven design approach for embedded control systems, which brings engineers from different disciplines in a natural way together. However the success of co-simulation depends on the quality of models used for testing, like the model used for testing the software, and whether the design environments allow for cooperation. A systematic workflow is presented to isolate and solve causes of unexpected behaviour. It uses parts of an existing approach, but is translated to a workflow for failure analyses at small mechatronic setups. It is valuable to evaluate the workflow for a new research setup during system engineering. The ViewCorrect Plotter setup has been improved. The pen mechanism is redesigned and a new configuration file is written for the FPGA board, which allows for generating multiple PWM signals at different frequencies to be able to control the pen height. Linear encoders have been implemented to the setup and a PCB is designed to process the plotter I/O. The PCB has the same form factor and is stackable with the existing CE H-bridge PCB to a complete electronic circuit to control a DC motor with an I/O board. A demonstration button, an emergency stop button and a brake stop button can now be connected.
Item Type:Essay (Master)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:54 computer science
Programme:Electrical Engineering MSc (60353)
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