Autonomous 2D microparticle manipulation based on visual feedback
ABSTRACT Autonomous two-dimensional manipulation of microparticles to form patterns under an optical microscope by pushing and pulling them with a sharp nanoprobe is presented. Camera calibration is done by an iterative sliding-mode parameter observer designed to satisfy the Lyapunov stability criterion. Estimated parameters are also used to increase the bandwidth on position control. Individual particles are manipulated in linear trajectories, utilizing a procedure that allows the particles to stick near the tip for horizontal motion and to get released for vertical motion. Patterns (and assemblies) of particles are generated using a planning algorithm that orders individual manipulations based on the blockage of linear trajectories by other particles or target positions. Basically, the particle that blocks the most number of trajectories is positioned to the target position that blocks the least number of trajectories. This ordering algorithm is a minimization of blockages to the linear trajectories and hence, performs better than the conventional distance-based approaches. Efficiency of the approach is demonstrated on experimental results, positioning 4.5 mum diameter polystyrene particles on a flat glass substrate autonomously. Average accuracy of individual manipulations is less than 0.64 mum.
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ABSTRACT: A theory is developed for the noncontact frictional forces between the sliding nanoasperity and substrate. The linear force–velocity dependence is substantiated. For weak contact the sliding friction force is proportional to the shear stress (surface energy) of the contact. Calculations are made of the friction forces for several nanotribosystems.Materials Letters. 01/1999;
Conference Proceeding: Plant behaviour dictation using a sliding mode model reference controller[show abstract] [hide abstract]
ABSTRACT: In this work, a sliding mode approach to model reference control of fully actuated electromechanical systems affine with control is presented. Instead of the traditional state error regulator between the desired model and the actual plant, the proposed approach utilizes the fact that on sliding mode, plant is enforced to remain on the sliding manifold. Performance of the controller is demonstrated on simulations and experiments on a piezoactuator. Results show that the approach is effective in dictating the nonlinear plant to behave as the desired linear model, so as to drive the piezoactuator for 1 nm step with only an open loop position controller in addition to the sliding mode model reference controller proposedAdvanced Motion Control, 2006. 9th IEEE International Workshop on; 02/2001
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ABSTRACT: This paper proposes a novel micro/nano scale manufacturing system using optical tweezers and chemical linkages for manufacturing two- and three- dimensional micro/nanostructures. A holographic multiple trap optical tweezer system is first used to trap particles in a desired pattern. The particles are then connected to form rigid units using suitable chemistry. Connection schemes based on gold seeding, complimentary-DNA linkage and streptavidin-biotin chemistry are presented and possible applications are explored.Robotica 01/2005; 23:435-439. · 0.88 Impact Factor