Tuesday 12pm, 5 September 2017


Interactive Design and Stability Analysis of Decorative Joinery for Furniture • Laika, the Quadruped Robot with a Tensegrity Spine

Eric (JiaXian) Yao - Drew Sabelhaus

PhD Students - UC Berkeley



High-quality hand-made furniture often employs intrinsic joints that geometrically interlock along mating surfaces. Such joints increase the structural integrity of the furniture and add to its visual appeal. We present an interactive tool for designing such intrinsic joints. Users draw the visual appearance of the joints on the surface of an input furniture model as groups of 2D regions that must belong to the same part. Our tool automatically partitions the furniture model into a set of solid 3D parts that conform to the user-specified 2D regions and assemble into the furniture. If the input does not merit assemblable solid 3D parts, our tool reports the failure and suggests options for redesigning the 2D surface regions so that they are assemblable. Similarly, if any parts in the resulting assembly are unstable, our tool suggests where additional 2D regions should be drawn to better interlock the parts and improve stability. To perform this stability analysis, we introduce a novel variational static analysis method that addresses shortcomings of the equilibrium method for our task. Specifically, our method correctly detects sliding instabilities and reports the locations and directions of sliding and hinging failures. We show that our tool can be used to generate over 100 joints inspired by traditional woodworking and Japanese joinery. We also design and fabricate 9 complete furniture assemblies that are stable and connected using only the intrinsic joints produced by our tool.


Walking robots, particularly those with four legs (quadrupeds), are able to navigate terrain that wheeled robots cannot. However, many quadrupeds still face challenges in highly uneven terrain, such as large rocks, often due to heavy and stiff designs of their bodies. This talk presents work on a new type of quadruped robot, named Laika, developed in collaboration with NASA. Laika has a flexible spine as its body, constructed using a lightweight tension-network design (a tensegrity), which can re-distribute its weight during locomotion for better balance. Laika's mechanical designs, control systems, and human-centered applications will be discussed. Both simulation and hardware will be presented that show Laika's spine moving its body, in anticipation of walking motions in future work.


Eric Yao

Eric (JiaXian) Yao is a Computer Science PhD student at UC Berkeley advised by Maneesh Agrawala. His main research area lies in Computer Graphics. In particular, he is interested in leveraging traditional woodworking techniques and developing design tools that enable novice users to readily create furniture.

Drew Sabelhaus

Drew (Andrew P.) Sabelhaus is a PhD student in Mechanical Engineering at UC Berkeley, and a NASA Space Technology Research Fellow at the NASA Ames Research Center Intelligent Robotics Group. Drew researches the control systems and designs of walking four-legged (quadruped) robots with flexible spines. He has published a total of 10 research papers on control systems and design, 8 of which involve tension network (tensegrity) structures, the type of system used in his current work. Drew has mentored a diverse group of 21 undergraduate and masters' students in total, and continues to be incredibly grateful for their research assistance. Drew was a NSF Graduate Research Fellow from 2012-2015. His CV can be found at