Analysis and Optimization of a Microgripper Driven by Linear Ultrasonic Motors.

This paper presents the vibration response analysis and optimal structural design of a microgripper driven by linear ultrasonic motors (LUMs) dedicated to improving end-point positioning accuracy. Based on structural vibration theory, a parametric vibration response model of the microgripper finger was established, and the relative sensitivities of the structural and material parameters that affect the vibration amplitude of the fingertip were calculated within the structural and material constraints. Then, according to the sensitivity calculation results, a multidimensional constrained nonlinear optimization model was constructed to suppress the vibration of the end-effector. The improved internal penalty function method combined with Newton iteration was adopted to obtain the optimal structural parameters. Finally, the vibration experimental results show that the vibration amplitude of the initial microgripper fingertip is 16.31 µm, and the value measured after optimization was 2.49 µm, exhibiting a reduction of 84.7%. Therefore, the proposed optimal design method can effectively restrain the vibration of the microgripper end-effector and improve manipulation stability.

Constructing NiSe2@MoS2 nano-heterostructures on a carbon fiber paper for electrocatalytic oxygen evolution.

Although MoS2 has shown its potential as an electro-catalyst for the oxygen evolution reaction (OER), its research is still insufficient. In this study, as a novel MoS2-based heterostructure electro-catalyst for OER, namely NiSe2@MoS2 nano-heterostructure, was constructed on a carbon fiber paper (CFP) substrate by a simple approach, which includes electrochemical deposition of NiSe2 film and hydrothermal processing of MoS2 film. In addition to a series of observations on the material structure, electrocatalytic OER performance of NiSe2@MoS2 was fully evaluated and further compared with other MoS2-based OER electro-catalysts. It exhibits an outstanding catalytic performance with an overpotential η 10 of 267 mV and a Tafel slope of 85 mV dec-1. Only 6% loss of current density before and after 10 h indicates its excellent durability. The results indicate that the obtained NiSe2@MoS2 is an excellent OER electro-catalyst and worth exploring as a substitute for noble metal-based materials.