Precision-based robot path planning for microassembly

Abstract

Growing complexity and heterogeneity in modern microsystems warrants new manufacturing standards beyond monolithic surface micromachining. Microassembly methods are among the front-runners for such standards that extend the capability of conventional MEMS in terms of reliability and manufacturability. Automated microassembly, however, is challenging, due to high precision requirements, limited assembly tolerance budgets in micro domain, difficulty to integrating sensors, surface force effects and so on. Control and planning during automated microassembly tasks need to be carefully designed and executed in order to achieve high yields and throughputs. In this paper we argue that, unlike conventional macroscale applications, the selection of a precision robotic manipulator and microassembly path planning are highly correlated at the microscale. At the same time, trajectory tracking is more difficult due to a low heteroceptive sensor density. We propose a novel precision-adjusted path planning algorithm (PPSA), in which the path precision is used as the primary cost metric, instead of the path distance. Preliminary simulation and experimental results indicate a precision improvement of PPSA over traditional shortest path algorithms.