Implementation of a state space controller in a FPGA

Results from the implementation of a stand-alone state space controller in a Field Programmable Gate Array (FPGA) circuit is presented. As a case study, an inverted pendulum is used as the controlled process. The process in non-trivial and reflects several industrially related control problems. The process states are estimated via a time-invariant Kalman filter. Two different CAD-tools are used: one for the design of the control system and another tool for the hardware. The hardware description language VHDL is used to model both the hardware and the process. These models formed a very useful test-bench in the hardware design system. Models of the process and the controller are designed in both systems. The problem of verifying that all models had a correct behaviour is solved by exchanging and comparing simulated input- and output-signals via ASCII-files between the two systems. The controller fits well within a 10,000 gate FPGA.