Positioning accuracy improvement of a vision-based optical fiber alignment motion stage based on fuzzy logic controller

In this paper, a vision-based optical fiber alignment motion stage powered by piezo-actuator (PEA) is developed. However, the tracking performance of PEA is limited due to its inherent hysteretic nonlinearity and time varying parameters. In order to cope with this problem, a novel feedforward inverse hysteresis model based on B-spline approximation is adopted to eliminate the adverse effects due to hysteresis. In addition, a fuzzy logic controller is designed to reduce the error caused by noise and modeling inaccuracy. Moreover, the idea of multi-rate control is exploited to deal with the vision latency problem. The feasibility of the proposed control scheme is verified under a variety of reference inputs. Experimental results show that the proposed approach exhibits satisfactory performance.