University of Twente Student Theses


Floating-point based control of the production cell using an FPGA with Handel-C

Sassen, Thijs (2009) Floating-point based control of the production cell using an FPGA with Handel-C.

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Abstract:The current design flow for embedded control applications within the control engineering group is based on models from which code can be generated for different hardware platforms. Tools that are used in this flow are 20-sim, 20-sim4C and gCSP. These tools support code generation for CPU based systems; an alternative to the CPU architecture is an FPGA architecture. In a previous project, the Production Cell system was ported from a CPU architecture toward an FPGA architecture with the use of the hardware description language Handel-C. The Production Cell consists of 6 parallel controlled motors which pass around metal blocks. The motors need to synchronize in order to operate correctly. The ported FPGA architecture is based on integer loop controllers due to FPGA-resource restrictions at that time. The ported system had a major drawback, the loop controllers had to be redesigned for the integer data type in stead of leaving it in floating-point resolution. This costed quite a lot of design effort. This project describes the design and realization of the Production Cell systemusing alternative loop controllers for an FPGA architecture. The goal is to find a loop controller which fits in the design flow with minimum FPGA-resource usage and design effort. The discussed alternative loop controllers are floating-point, fixed-point, hard-core and softcore with a floating-point unit. The floating-point loop controller is the best one to use, taking in mind the requirements of the loop controller. To minimize the FPGA-resource usage the floating-point loop controller is implemented by controlling the 6 motors in the Production Cell sequentially using one controller. With this sequential control, the existing Production Cell software framework needs to be redesigned due to the fact that it was based on parallel control. The new Production Cell framework includes an improved safety layer, which can detect deadlock and system errors. This is possible because all sensor and motor information is available in a global safety layer. The outcome of this project showed that it is possible to control the Production Cell with a loop controller that fits in the current design flow while gaining more precision without using too much FPGA-resources. During the investigation on alternative loop controllers the soft-core and hard-core alternatives showed to be promising, but could not be investigated, because the FPGA that needs to be used for these alternatives was not operational. Therefore, it is recommended that these alternatives need further investigation as soon as this FPGA is operational
Item Type:Essay (Master)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:53 electrotechnology
Programme:Electrical Engineering MSc (60353)
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