Papers by Author: Wei Bin Rong

Abstract: Flexible and reliable gripping is a fundamental task in various micromanipulation and microassembly fields. Shape-controllable menisci based on pressure adjustment were proposed to pick up microobjects. Lifting force is provided by a controllable liquid bridge which is formed between the capillary tube and the microobject. The volume and the shape of the meniscus could be regulated dynamically by changing the pressure at the capillary nozzle orifice, thus the capillary force alters correspondingly. The pressure adjustment was realized by adjusting the height of the reservoir device precisely. Fluent software was used to simulate the fluid meniscus under different pressures. Experiments were performed to achieve controllable meniscus with different height difference of liquid level between the reservoir device and the capillary nozzle orifice, and microobjects griping operations were executed to verify the method.

Abstract: In this paper, we focus on the need for real time nanomanipulation, a 3D Master/Slave tele-nanomanipulation platform is studied with the haptic device (Omega3) as the master and the nanopositioner (Attocube) as the slave, working in scanning electron microscope (SEM). The 3D manipulation environment is developed with the help of VR technology. The platform is controlled by the enhanced virtual coupling (EVC) algorithm. The stability of the platform is discussed with Llewellyns stability criteria. Scale factors and enhancement factor of the control system are determined, according to the force applied on master and slave terminals. Performances of the platform are tested with the ZnO nanowire manipulation experiments. Experiment results show that the platform has good performance while guaranteeing stability on ZnO nanowires manipulation in SEM using the method presented in this paper.

Abstract: Influence of the Tabor parameter on the roughness-induced adhesion hysteresis was investigated. To achieve this, the adhesive contact model of single asperities was considered by incorporating the Maugis-dugdale model and its corresponding extension firstly. Further more, the load-approach relationship of adhesive contact between a rough surface and a flat was analyzed. The dissipation energy during a load and unload cycle is derived for general values of the Tabor parameter. It was found that the adhesion hysteresis becomes weaker gradually with the increase of the adhesion parameter, and it becomes stronger with the decrease of the Tabor parameter at the same adhesion parameter. The adhesion hysteresis for a special case that rough surfaces with DMT(Deryagin-Muller-Toporov)-type asperities is also discussed.

Abstract: The meniscus force between nanoobjects with a mediated liquid bridge plays an important role in many applications due to scale effects. As an typical configuration, the meniscus force between two spherical nanoparticles at various humidities is studied theoretically. The numerical method and the usual approximation method of calculating the meniscus force at various humidities are compared firstly. It is found that the big error may occur at some conditions. The effects of relative humidity on the meniscus force between spherical nanoparticles are investigated. Besides, the influences of spherical radius, the distance between nanoparticles, contact angles of the liquid on the meniscus forces between spherical nanoparticles are studied. The simulation results are helpful to understand and control the adhesion force at nanoscales.

Abstract: The dynamic separation of two parallel microplates with an intervening liquid meniscus is studied theoretically. The dynamic model considering the meniscus force and the viscous force between the plates in the separation process was developed. With typical simulation parameters, the magnitudes of various forces were compared before the separation of two parallel plates occurs. It was found that the meniscus force decreases gradually with the increase of separation distance. However there is a sudden jump of the viscous force before it gradually increases, then it decreases dramatically. The influences of various parameters on the separation time were investigated. It was found that the separation time increases with the mass of the upper plate, surface tension, viscosity and volume of the liquid. The separation time decreases with the initial distance and the contact angles of the liquid.

Abstract: An integrated micro xy-stage is designed and fabricated for application in nanometer-scale operation and nanometric positioning precision. This device integrates the functions of both actuating and sensing in the same silicon ship and is mainly composed of a silicon-based xy-stage, electrostatics comb actuator and a displacement sensor. In this paper a robust control strategy based on single neuron adaptive PID control theory is developed for silicon-based xy-stage, considering electrical, mechanical, and stiffness models. Single neuron adaptive PID control enables compact realization of a robust controller tolerant of device characteristics variation, types of inherent instabilities, and improving dynamical characteristics. The experimental results verified that the controller is more suitable for the silicon integrated micro xy-stage, under which the settling time is less than 2.5ms and the repeatability error is better than ±24.9nm. In addition, the presented control scheme is simple to implement in practical application.