Robotic additive manufacturing with toy blocks

We develop and study a block-type three-dimensional (3D) printer that can assemble toy blocks based on 3D CAD models. Our system automatically converts a 3D CAD model into a block model consisting of toy blocks in basic shapes. Next, it automatically generates a feasible assembly plan for the block model. An industrial robot then assembles the block sculpture layer-by-layer, from bottom to top, using this assembly plan. This approach has advantages including the ease of combining multiple types of materials and reusing them which is difficult for conventional 3D printers to accomplish. We also introduce a technique to reliably determine the order of block placement to assemble block models from various patterns. This technique includes converting unassemblable shapes in the models to assemblable ones with support blocks and/or decomposing them into subassemblies. In addition, we implement a robot control system that automatically generates a stable sculpture according to a predetermined placement order. We also demonstrate the assembly of various toy block models using our system.