Shixun Fan

Design and modeling of a novel monolithic parallel XY stage with centimeters travel range

Since most of XY positioning stages with large travel range proposed by former researchers suffer from loose structure and low out-of-plane payload, this article presents a novel monolithic parallel XY stage based on spatial prismatic–prismatic joints with centimeters travel range, compact size, and high out-of-plane payload capacity. The novel parallel linear compliant mechanism of the stage is composed of four spatial prismatic–prismatic joints, which is two compound leaf spring parallelograms serially connected in cubical space to obtain large travel, compact size, and high out-of-plane payload capacity simultaneously. The theoretical static stiffness and resonant frequencies are obtained by matrix structural analysis. As a case study, a reified stage is presented and discussed in detail. Finally, theoretical models are comprehensively compared with finite element analysis models. It is shown that the stage in the case study has the following merits: large travel range up to 20 × 20 mm2, high-area ratio of workspace to the outer dimension of the stage about 2.26%, well-constrained cross-axis coupling motion less than 1.5 μm at the full primary motion, acceptable resonant frequencies of the two translational axes about 34 Hz, and large out-of-plane payload capacity more than 24 kg.

Vibration suppression in a harmonic drive system

In this paper, a composite control method combined a finite-duration impulse-response digital (FIR) filter and an additional feedback of the difference between the motor and load speeds is proposed to suppress the vibration. The structure of the composite control is analysed, where the FIR filter is used to suppress the resonance of the compliant buffer shelf, the additional feedback of the difference between the motor and load speeds is used to suppress the resonance of the harmonic gear tram. Simulation results validate the control algorithm.

Design and modeling of a miniaturized long stroke optical micro scanner

This paper presents the design and finite element modeling of a miniaturized long stroke optical micro scanner. The concept mechatronic design of the device is introduced. A kind of finite element modeling technique based on modal analysis is utilized to bridge the gap between the state space servo model and the mechanical structural geometric parameters of the designed scanner. The eigenvalues and the eigenvectors of the first 20 modes of the scanner are calculated with ANSYS. A 40th order 2 inputs 3 outputs state space model is built by using the eigenvalues and the eigenvectors given by ANSYS. Balanced truncation model reduction method is utilized to reduce the orders of the state space model. A 10th order 2 inputs 3 outputs state space model is obtained. Frequency responses comparison between different models is conducted. The comparison results show that the 10th order 2 inputs 3 outputs state space model can efficiently characterize the vibration and the cross coupling dynamics of the designed miniaturized long stroke optical micro scanner within the frequency range below 500 Hz.