Micro-Assembly Sequence and Path Planning Using Subassemblies

Abstract

This paper presents a novel assembly sequence planning (ASP) procedure utilizing a subassembly based search algorithm (SABLS) for micro-assembly applications involving geometric and other assembly constraints. The breakout local search (BLS) algorithm is adapted to provide sequencing solutions in assemblies with no coherent solutions by converting the final assembly into subassemblies which can be assembled together. This is implemented using custom-made microparts which fit together only in a predefined fashion. Once the ASP is done, the parts are manipulated from a cluttered space to their final positions in the subassemblies using a path-planning algorithm based on rapidly exploring random tree (RRT*), a random-sampling based execution, and micromanipulation motion primitives. The entire system is demonstrated by assembling LEGO® inspired microparts into various configurations which involve subassemblies, showing the versatility of the system.

Cyber-Physical Systems for Micro-/Nano-assembly Operations: a Survey

“…A similar closed-loop control strategy is presented in [46] in which the 3D CAD is also used to present a complete description of the observed scene, including the effects of occlusion, for a 6-DOF tracking in real time. The works of Venkatesan et al [47] and Venkatesan and Cappelleri [48] are based on sub-assembly sequence generation to find each optimal trajectory by a learned algorithm. Kim et al [49] present a dexterous and fast micro-hand (1 mm/s) system used for a high-speed (100-μm spheres in 800 ms and 1.54 mm in 13 s) and precise assembly method at a large distance (13 mm) by implementing automatic releasing and error recovery system.…”