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We proposed a plasmonic structure consisting of uniform metallic nanoslits with a movable dielectric substrate for subwavelength beam manipulation. In this structure, the phase of incident light can be modulated beforehand by the substrate before bumping the metal slits; therefore, the shape of transmitted light from nanoslits can be actively controlled by changing the substrate profile. According to this idea, plasmonic lenses with different functions, such as focusing light to two points, focus length variation, and beam deflection, are designed and investigated numerically. The proposed structure has a unique advantage of multifunction and reduces the difficulty in fabrication.

External vibration, shock, unbalanced torque and other uncertain disturbances are mainly transmitted to the motor rotor through the bearing friction. To restrain the uncertain friction disturbances and improve the speed stability of a permanent magnet synchronous motor (PMSM), an optimized active disturbance rejection control (ADRC) algorithm is proposed in this study. Firstly, an auxiliary model of friction and a reduced-order processing method are introduced into extended state observation (ESO) to reduce the burden of single ESO and promote the compensation accuracy of disturbances. In addition, a supervisory radial basis function (SRBF) is employed to supervise and promote the error elimination efficiency of the nonlinear state error feedback rate (NLSEF). The hybrid control algorithm makes up for the deficiency of typical ADRC through the fusion of multiple control quantities. Simulation and experimental results show that the proposed algorithm has strong anti-disturbance performance and effectively solves the problem of low-speed crawling.

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