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1. Compact Tensegrity Robots Capable of Locomotion through Mass-shifting

   Rhodes, T. ; Vikas, V. ( August 2019 , Proceedings of the ASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference)

   Robustness, compactness, and portability of tensegrity robots make them suitable candidates for locomotion on unknown terrains. Despite these advantages, challenges remain relating to simplicity of fabrication and locomotion. The paper introduces a design solution for fabricating tensegrity robots of varying morphologies with modular components created using rapid prototyping techniques, including 3D printing and laser-cutting. % It explores different robot morphologies that attempt to balance structural complexity while facilitating smooth locomotion. The techniques are utilized to fabricate simple tensegrity structures, followed by tensegrity robots in icosahedron and half-circle arc morphologies. Locomotion strategies for such robots involve altering of the position of center-of-mass to induce `tip-over'. Furthermore, the design of curved links of tensegrity mechanisms facilitates continuous change in the point of contact (along the curve) as compared to piece-wise continuous in the traditional straight links (point contact) which induces impulse reaction forces during locomotion. The resulting two tensegrity robots - six-straight strut icosahedron and two half-circle arc morphology - achieve locomotion through internal mass-shifting utilizing the presented modular mass-shifting mechanism. The curve-link tensegrity robot demonstrates smooth locomotion along with folding-unfolding capability.
2. Acoustic Communication and Sensing for Inflatable Modular Soft Robots

   https://doi.org/10.1109/ICRA48506.2021.9561183  

   Drew, Daniel S. ; Devlin, Matthew ; Hawkes, Elliot ; Follmer, Sean ( May 2021 , 2021 IEEE International Conference on Robotics and Automation (ICRA))

   Modular soft robots combine the strengths of two traditionally separate areas of robotics. As modular robots, they can show robustness to individual failure and reconfigurability; as soft robots, they can deform and undergo large shape changes in order to adapt to their environment, and have inherent human safety. However, for sensing and communication these robots also combine the challenges of both: they require solutions that are scalable (low cost and complexity) and efficient (low power) to enable collectives of large numbers of robots, and these solutions must also be able to interface with the high extension ratio elastic bodies of soft robots. In this work, we seek to address these challenges using acoustic signals produced by piezoelectric surface transducers that are cheap, simple, and low power, and that not only integrate with but also leverage the elastic robot skins for signal transmission. Importantly, to further increase scalability, the transducers exhibit multi-functionality made possible by a relatively flat frequency response across the audible and ultrasonic ranges. With minimal hardware, they enable directional contact-based communication, audible-range communication at a distance, and exteroceptive sensing. We demonstrate a subset of the decentralized collective behaviors that these functions make possible with multi-robot hardware implementations. Themore »use of acoustic waves in this domain is shown to provide distinct advantages over existing solutions.« less
3. Acoustic Communication and Sensing for Inflatable Modular Soft Robots

   Daniel S. Drew, Matthew Devlin ( January 2021 , IEEE International Conference on Robotics and Automation)

   Modular soft robots combine the strengths of two traditionally separate areas of robotics. As modular robots, they can show robustness to individual failure and reconfigurability; as soft robots, they can deform and undergo large shape changes in order to adapt to their environment, and have inherent human safety. However, for sensing and communication these robots also combine the challenges of both: they require solutions that are scalable (low cost and complexity) and efficient (low power) to enable collectives of large numbers of robots, and these solutions must also be able to interface with the high extension ratio elastic bodies of soft robots. In this work, we seek to address these challenges using acoustic signals produced by piezoelectric surface transducers that are cheap, simple, and low power, and that not only integrate with but also leverage the elastic robot skins for signal transmission. Importantly, to further increase scalability, the transducers exhibit multi-functionality made possible by a relatively flat frequency response across the audible and ultrasonic ranges. With minimal hardware, they enable directional contact-based communication, audible-range communication at a distance, and exteroceptive sensing. We demonstrate a subset of the decentralized collective behaviors these functions make possible with multi-robot hardware implementations. The usemore »of acoustic waves in this domain is shown to provide distinct advantages over existing solutions.« less
4. Design and Implementation of Experiential Learning Modules for Reinforced Concrete

   Lovell, Matthew D. ; Carroll, J. Chris ; Kershaw, Kyle ; Derks, Alec C. ( January 2021 , ASEE annual conference exposition)

   Most undergraduate civil engineering programs include an introductory course in reinforced concrete design. The course generally includes an introduction to the fundamentals of reinforced concrete behavior, the design of simple beams and one-way slabs to resist shear and flexure, and the design of short columns. Because of the scale of typical civil engineering structures, students commonly do not get to experience large or full-scale structural behavior as a part of an undergraduate reinforced concrete course. Rather, students typically learn fundamental concepts through theoretical discussions, small demonstrations, or pictures and images. Without the interaction with full-scale structural members, students can struggle to develop a clear understanding of the fundamental behavior of these systems such as the differences in behavior of an over or under-reinforced beam. Additionally, students do not build an appreciation for the variations between as-built versus theoretical designs. Large-scale models can illustrate such behavior and enhance student understanding, but most civil engineering programs lack the physical equipment to perform testing at this scale. The authors from St. Louis University (SLU) and Rose-Hulman Institute of Technology (RHIT) have designed and implemented large-scale tests for in-class use that allow students to experience fundamental reinforced concrete behavior. Students design and test severalmore »reinforced concrete members using a modular strong-block testing system. This paper provides a detailed overview of the design, fabrication, and implementation of three large-scale experiential learning modules for an undergraduate reinforced concrete design course. The first module focuses on service load and deflections of a reinforced concrete beam. The first and second modules also focus on flexural failure modes and ductility. The third module focuses on shear design and failure modes. Each module uses a large scale reinforced concrete beam (Flexure specimens: 12 in. x 14 in. x 19 ft, Shear specimens: 12 in. x 14 in. x 10 ft.) that was tested on a modular strong-block testing system. The three modules were used throughout the reinforced concrete design course at SLU and RHIT to illustrate behavior concurrent to the presentation of various reinforced concrete design concepts.« less
5. Real-Time Distributed Cloud Computing Architecture for Structural Health Monitoring

   https://doi.org/10.1061/9780784482230.005  

   Searls, Owen ; Zhao, Zhiyong ; Couch, Alva L. ; Sanayei, Masoud ( April 2019 , Structures Congress Conference 2019)

   Real-time fatigue health monitoring has the potential to serve as a valuable complement to structural health monitoring (SHM) for bridge inspections. SHM is an objective supplement to visual bridge inspections with a minimum interval between bridge inspections at 24 months. SHM can provide quantitative and objective data on a bridge’s fatigue condition for fracture-critical components, of which fatigue is a criterion. Current methods of continuous structural health monitoring for condition assessment are performed by collecting measured bridge response subjected to operational traffic from an array of sensors installed on fracture-critical members of a bridge. The measured responses are used to determine the remaining fatigue life of the bridge—the minimum time before repair. The large amount of data involved in this process complicates the design of a system that will automate the data collection process at a bridge, analyze that data, and display information about bridge health to researchers and engineers. Variations in bridge designs and condition assessment algorithms also necessitate that such a system be modular and adaptable to allow for expansion to additional structures. A new system has been developed that separates bridge SHM from the data storage and communication system. This architecture creates a reliable interface for sendingmore »data from one or more bridges to a cloud server where it can be processed using modular algorithms that can be adapted for different use cases. The cloud-based web service and data repository makes bridge structural health data available to researchers at all steps of the process. This system provides significant advantages over previous platforms for structural health monitoring and condition assessment, most notably in the areas of modularity, extensibility, and reliability.« less