Modeling and simulation of the dynamics, contact mechanics and control of the nanomanipulation of elliptical porous alumina nanoparticles based on atomic force microscopy

Abstract

Nowadays, AFM-based robots are widely utilized for transporting different nanoparticles. Using this devise as a tool for nanomanipulation, it is possible to specify the exact location of a nanoparticle in micro/nano-scale. In the fields of dynamics, contact mechanics and control of nanomanipulation for atomic force microscopy, accurate investigation and analysis of the motion of nanoparticles and the robustness of the control algorithm are among the most important goals that arise. In fact, one tries to achieve these two goals by applying the appropriate dynamics and control to the system. Moreover, the controlled displacement of nanoparticles and accurate and proper dynamic modeling can greatly help manipulation. Therefore, in the present study, static, dynamic, and contact mechanics models for the nanomanipulation of elliptical porous alumina nanoparticles were developed. Also, sliding and rolling modes were considered for this type of nanoparticles. The dynamic results showed that, for elliptical porous nanoparticles, increasing the porosity coefficient first leads to sliding and increases the difference between the forces required for sliding and rolling. However, for simple elliptical nanoparticles, the particle first rolls and then slides on the surface. In addition, by using contact mechanics equations, the penetration depth between the nanoparticle and the substrate and that between the nanoparticle and the tip were calculated to be approximately 6.2 nm and 1.4 nm, respectively. Subsequently, a sliding mode controller was modeled in order to control the deviation of the probe from the vertical and the displacement in the direction of motion. The results showed that convergence was achieved in less than 0.1s for all porosity coefficients considered.