FPGA-realization of a motion control IC with adaptive fuzzy control for an X-Y table

In this paper, a motion control IC for the X-Y table using FPGA (Field Programmable Gate Array) technology is presented. In the controller design, to alleviate the effect of unmodelled dynamics and cross interferences while two tables are simultaneously in motion, an AFC (Adaptive Fuzzy Controller) is applied in the position loop of the X-Y table to improve the motion tracking performance. In implementation, an FPGA embedded by a Nios II processor is adopted to design the overall circuits of the motion control IC which the schemes of position/speed/current control for two PMSMs (Permanent Magnet Synchronous Motors) are realized by hardware in FPGA and the motion trajectory algorithm for the X-Y table is realized by software using a Nios II embedded processor. Further, to reduce the use of FPGA resources, an FSM (Finite State Machine) joined by a multiplier, an adder, several comparators and registers is presented to model the overall AFC. VHDL (VHSIC Hardware Description Language) is adopted to describe the FSM. At last, an experimental system with an X-Y table, one FPGA board, two inverters, four ADCs (Analog-to-digital Converter) and some comparator ICs for QEP (Quadrature Encoder Pulse) detection is set up. The experimental results, such as the effect of the cross inferences in simultaneous motion of the X-Y table and the tracking performance of two-dimensional motion trajectory are also verified to prove the effectiveness of the proposed FPGA-based motion control IC.