Chek-Sing Teo

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The scanning accuracy of piezoelectric mechanisms over broadband frequencies is limited due to inherent dynamic hysteresis. This phenomenon has been a key bottleneck to the use of piezoelectric mechanisms in fast and precision scanning applications. This paper presents a systematic model identification and composite control strategy without hysteresis(More)
Ultrasonic motors used in high-precision mechatronics are characterized by strong frictional effects, which are among the main problems in precision motion control. The traditional methods apply model-based nonlinear feedforward to compensate the friction, thus requiring closed-loop stability and safety constraint considerations. Implementation of these(More)
Jerk derivative feedforward control is proposed and used in recent literatures. However, such feedforward control scheme is restricted to the minimum-phase system which has constrained static gains in the flexible modes. This paper presents a novel form of feedforward controller for a wider class of flexible motion systems, even to be non-minimum phase, as(More)
A novel radial basis function (RBF) neural network-based geometric error compensation method with displacement measurements only is proposed in this paper. The individual geometric error components are formulated mathematically based on laser interferometer calibration with displacement measurements only and modeled using RBF neural network for error(More)