skip to main content

Explore Research Products in the NSF-PAR

  • Home
  • Search Results
  • Page 1 of 1

Search for: All records

Creators/Authors contains: "Liu, Yifang"

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. ; ; ; ; ; ; ( , ACS Sensors)
  2. ; ; ( , 12th Conference on Field and Service Robotics (FSR19))
    Abstract Dry stacking with found, minimally processed rocks is a useful capability when it comes to autonomous construction. However, it is a difficult planning problem since both the state and action space are continuous, and structural stability is strongly affected by complex friction and contact constraints. We propose an algorithmic approach for autonomous construction from a collection of irregularly shaped objects. The structure planning is calculated in simulation by first considering geometric and physical constraints to find a small set of feasible actions and then refined by using a hierarchical filter based on heuristics. These plans are then executed open-loop with a robotic arm equipped with a wrist RGB-D camera. Experimental results show that the proposed planning algorithm can significantly improve the state of the art robotics dry-stacking techniques. 
    more » « less
    Accepted Manuscript Full Text Available
  3. ; ; ; ( , International Conference on Robotics and Automation (ICRA2019))
    We introduce a fast approximate stability analysis into an automated dry stacking procedure. Evaluating structural stability is essential for any type of construction, but especially challenging in techniques where building elements remain distinct and do not use fasteners or adhesives. Due to the irregular shape of construction materials, autonomous agents have restricted knowledge of contact geometry, which makes existing analysis tools difficult to deploy. In this paper, a geometric safety factor called kern is used to estimate how much the contact interface can shrink and the structure still be feasible, where feasibility can be checked efficiently using linear programming. We validate the stability measure by comparing the proposed methods with a fully simulated shaking test in 2D. We also improve existing heuristics-based planning by adding the proposed measure into the assembly process. 
    more » « less
    Accepted Manuscript Full Text Available