Semi-Automated Control of AFM-based Micromanipulation using Potential Fields

This paper proposes a truly interactive virtual environment (VE) system for 2D assembly tasks at the microscale. It is based on the application of virtual potential fields as a control aid for performing safe and reliable path planning strategies. The planner covers a whole range of problems due to microscale effects in object assignment, obstacle detection and avoidance, path trajectory finding and sequencing. We investigated various paradigms for enabling the human operator and the automatic motion planner to cooperatively solve a motion planning task through the use of virtual potential fields. Communication between the operator and the planner is made through haptic/vision/sound modalities. First, we describe algorithms based on optimization theory and Voronoi graph construction taking into account the microscale effects. As automatic motion planners fail due to the difficulty of discovering critical configurations, we propose cooperation paradigms with operator skills in order to solve motion planning strategies. Then, potential fields are being used as a tool to generate velocity commands from an automatic path planner as well as allowing the human to interact. Finally, the ideas presented here are supported by experiments for efficient pushing-based manipulation constructing 2-D microparticle patterns.