Research On Kinematics Modeling Of Nano-objects And Nanomanipulation Method In Uncertain Conditions

Observation and manipulation at nanoscale are the key method for developing nanotechnology,finding the new features of nanomaterial and fabricating the nanodevices.Atomic Force Microscopy(AFM)has some characteristics such as high resolution for observation,high precision for motion and its job pattern with repeatability and controllability,so it currently has been a very great potential nanomanipulation tool in nano-oberservation and nanomanipulation.But there are many uncertainties in the AFM system such as hysteresis,creep and temperature drift,then the nano-object and the AFM tip both have positioning errors,it is one of the factors that affect the operation of the nanomanipulation.Furthermore,the AFM tip only can exert force at one point of the operated object which makes the tip lost the object in the manipulation process.The existing nano-operating system cannot realize the high precision,fixed posture and high stability nanomanipulation.In this dissertation,an innovative nanomanipulation method under uncertain conditions is researched based on the analysis of domestic and overseas researches.The main contents are shown as follows:The kinematics models of nano-objects based on AFM pushing are established.The behavior and the force of nanoparticle under AFM pushing are theoretically analyzed,then kinematics models of the nanoparticle and the nanorod are established.The parameters in the models are calibrated using the experimental method.By modeling,the position of the nano-objects can be determined at each manipulation in real time,so the stable and reliable nanomanipulation can be realized.The numerical simulation and experimental results show validity of the proposed model.In order to improve the accuracy of nanoparticle kinematic model,the improved model of the nanoparticle based on least action principle is suggested.At first,the distribution rule of the nanoparticle rotation center under the minimum pushing force is proved,then the forces and the torques exerted on the nanoparticle are analyzed,according to the forces and the torques are both balanced,the improved kinematic model is established.Due to the complexity of the formula,it is difficult for the manipulation model to get analytic solution.Numerical methods including Runge-Kutta and Monte-Carlo are used for solving equation of model.Through the comparison between simulation experiment and real manipulation results,the parameters of the calibration are adjusted to achieve the best results.The experiments on the foundation of experimental analysis and algorithm program debugging illustrate the nanoparticle manipulation model efficiently.There are many uncertainties in nano operating environment,the system temperature drift uncertainty,the tip topography uncertainty and the tip positioning uncertainty are the main factors.In order to resolve temperature drift problem,the real-time feedback nanomanipulation system based on the local scan is proposed.The morphology method is proposed to estimate the tip shape through imaging regular spherical nano-particle.A tip positioning method is proposed to localize the tip by using landmark observation,the observation model and the tip motion model are established,then the kalman filter is applied to optimally estimate the tip position.AFM only has one tip as the actuator and this is one of the reasons that AFM cannot able to achieve stable operation,the virtual nano-hand strategy is suggested to solve the problem.This strategy by moving the AFM tip to a set of predefined positions and generating a short pushing action to the target object from those positions in relative high frequency mimic multi-fingered hand and can achieve the effect of multi-tip manipulation with a single AFM tip.Due to the error distribution characteristics of the tip and the nano-objects positions,Monte Carlo method is adopted to describe and predict the position uncertainty and error distribution.Based on the kinematic model of the nanoparticle,the pushing parameters of the AFM tip are planned,the parameters performance and optimized method of the virtual hand structure are analysized.Simulation results demonstrate the validity of the suggested strategy.At last,the performance of nano-hand parameters and the optimization methods are analyzed.The AFM nanomanipulation platform with the real time feedback is established.A lot of experimental results verify the validity of the proposed methods.At the same time,the program simulation presents the efficiency of the virtual nanohand strategy which can highly promote the nanomanipulation efficiency verified by the related experimental results.