Research Projects

Build-a-Bot: Computer-Aided Interactive Robot Design

Build-a-Bot software interface allows users to explore how changes in a legged robot design change its trajectory
Our approaches leverage graph-based representations of the robot’s kinematic and electronic structure, combined with optimization and search techniques to create feasible designs.
Sample robots created using our tools

We aim to democratize robotics by making engineering design intuitive and accessible to everyone through computation. Currently robot design is a time and skill intensive process requiring years of training and multiple iterations of prototyping and testing. Unlocking the full potential of ubiquitous robotics requires new intelligent design tools that support experienced and novice users alike in the design process, from ideation to prototyping to validation stages.

Our goal is to develop algorithms and tools for co-design of a robot’s mechanical, electronic, and software components. Using a combination of computational geometry, mechanics modeling, simulation and optimization techniques, we create computational frameworks for designing, fabricating, and controlling robots that are robust to task, environment, and fabrication uncertainties. Unlike static objects, robots rely on complex interactions with their surrounding environment, and their performance is therefore very dependent on their physical designs. We focus on algorithms for design synthesis that provide designs based on evaluated efficiency and robustness tradeoffs.

Our current active projects include:

  • Automated exploration of robot topology and geometry
  • Co-design of robot controllers and electronics incorporating sensing, actuation, and dynamical constraints
  • Studies on usability and feedback useful to users for interactive robot design

Personnel: Wei-Hsi Chen, Daniel Feshbach, Dongsheng Chen

Components of this project are supported by NSF Grant 1845339.

Selected Publications:

Dongsheng Chen, Zonghao Huang, Cynthia Sung: Electronics Design and Verification for Robots With Actuation and Sensing Requirements. ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference (IDETC/CIE), 2023.
Zonghao Huang, Quinn Wu, David Howard, Cynthia Sung: EvoRobogami: Co-designing with Humans in Evolutionary Robotics Experiments. Genetic and Evolutionary Computation Conference (GECCO), 2022.
Adriana Schulz, Cynthia Sung, Andrew Spielberg, Wei Zhao, Yu Cheng, Eitan Grinspun, Daniela Rus, Wojciech Matusik: Interactive Robogami: An end-to-end system for design of robots with ground locomotion. In: International Journal of Robotics Research, vol. 36, no. 10, pp. 1131-1147, 2017.

Designable Compliance for Soft and Semi-Rigid Robots Capable of Dynamical Behaviors

3D printed TPU structures with controllable compliance and anisotropy using geometric parameters
Geometric parameters of the mechanism can be manipulated to control its stiffness.
Folding mechanics produce natural motions with few actuators

We leverage the inherent mechanics of robots to make them robust and energy-efficient. Compared to traditional rigid robot designs, compliant robots offer greater flexibility and adaptability, but this comes at a high cost of design and fabrication complexity. Our strategy is to design new compliant mechanisms whose inherent mechanics are controlled by geometric parameters, enabling engineers to tune a robot’s natural response independently of its materials and method of fabrication, or a robot to tune its own behavior on site.

We are particularly interested in lattice and tessellation structures and small topological and geometric changes produce different anisotropies, snap-through, or buckling behavior. We develop reduced-parameter models for these designs and demonstrate both theoretically and experimentally how these parameters can be optimized for specific applications, including manipulation, robotic reconfiguration, and jumping.

Our current active projects include:

  • Mechanical characterization of 3D printed lattices using compliant materials such as TPU
  • Snap-through design for morphological reconfiguration in systems including an hybrid aerial vehicle, a bistable gripper, and a jumper
  • Experimental exploration on the effect of compliance on robot performance and efficiency in dynamical tasks, including a hybrid aerial vehicle and underwater swimmer

Personnel: Jessica Weakly, Dongsheng Chen, Shivangi Misra

Components of this project are supported by NSF Grant 2121887 and by ONR Award #N00014-23-1-2068, and are performed in collaboration with the Science of Learning Innovation and Control, Embodied MURI Program.

Selected Publications

Shivangi Misra, Mason Mitchell, Rongqian Chen, Cynthia Sung: Design and Control of a Tunable-Stiffness Coiled-Spring Actuator. IEEE International Conference on Robotics and Automation (ICRA), 2023.
Zhiyuan Yang, Dongsheng Chen, David J. Levine, Cynthia Sung: Origami-inspired robot that swims via jet propulsion. In: IEEE Robotics and Automation Letters, vol. 6, no. 4, pp. 7145-7152, 2021.
Xuan Li*, Jessica McWilliams*, Minchen Li, Cynthia Sung, Chenfanfu Jiang: Soft hybrid aerial vehicle via bistable mechanism. IEEE International Conference on Robotics and Automation (ICRA), 2021, (*=co-first author, best paper in mechanisms and design).

Rapid Fabrication and Assembly of Folding Machines

Print-and-fold robot fabricated from one continuous sheet of plastic with embedded electronics
Origami-inspired fabrication enables the behavior of the robot to be programmed directly into the fold pattern. This robot uses a bistable pattern and a simple latch-based actuator to jump.
Lamination-based fabrication yields patterns that self-fold when exposed to heat so that robots can assemble and immediately deploy without direct intervention

We investigate new ways to use and combine existing digital manufacturing tools such as 3D printing, lamination, and origami-inspired assembly to construct robots within hours. Print-and-fold manufacturing promises customizable robots with embedded actuation, sensing, and electronics. These processes create devices that are low-weight, low-power, and low-cost, and that can produce complex behaviors with relatively simple actuation requirements. Due to inbuilt compliance and alterable crease pattern parameters, different behaviors can be programmed directly into the bodies of these robots.

We create new systems for streamlining this fabrication by embedding fabrication constraints into computational tools, automatically converting designs into valid plans that can be sent straight to the printer. We develop reduced-order models to predict the behavior of the fabricated structures and to design origami-inspired robots for particular tasks. By taking advantage of active materials such as shape memory polymers, we also develop new self-folding and self-assembly processes to turn virtual robot designs into physical designs with minimal human assembly.

Our current active projects include:

  • Distributed actuation using smart materials embedded into a multi-layer origami pattern, enabling active stiffness control in a soft robotic manipulator and an adjustable pulmonary artery band
  • Design of origami mechanisms for minimal actuation in applications including jumping and swimming
  • Modeling of curved crease patterns for achieving desired folding motions while minimizing origami pattern complexity
  • Design and fabrication approaches for self-folding of complex origami patterns requiring sequential folding

Personnel: Gabriel Unger, Daniel Feshbach, Wei-Hsi Chen

Components of this project are supported by the Johnson & Johnson WiSTEM2D Scholars Program, by the Children’s Hospital of Philadelphia, and by the Penn Health-Tech Pilot Award Program.

Selected Publications

Addison Liu, Mykell Johnson, Cynthia Sung: Increasing Reliability of Self-Folding of the Origami Hypar. In: ASME Journal of Mechanisms and Robotics, vol. 14, no. 6, pp. 061003, 2022.
Sehyuk Yim, Cynthia Sung, Shuhei Miyashita, Daniela Rus, Sangbae Kim: Animatronic soft robots by additive folding. In: International Journal of Robotics Research, vol. 37, no. 6, pp. 611-628, 2018.
Cynthia Sung, Rhea Lin, Shuhei Miyashita, Sehyuk Yim, Sangbae Kim, Daniela Rus: Self-folded soft robotic structures with controllable joints. IEEE International Conference on Robotics and Automation (ICRA), 2017.
Cynthia Sung, Daniela Rus: Foldable joints for foldable robots. In: ASME Journal of Mechanisms and Robotics, vol. 7, no. 2, pp. 021012, 2015.

Modeling, Planning, and Control for Reconfigurable Robots

Hybrid aerial vehicle leveraging compliant mechanism for reconfiguration
Modular, reconfigurable, tendon-driven truss

Self-reconfiguring robots and programmable matter smart materials, which can morph themselves to achieve a wide variety of different shapes and stiffnesses as tasks demand, are ideal for flexible and adaptable functionality. Compliant mechanics offer unique opportunities to enable high degree of freedom reconfigurability with reduced actuation and control.

We are interested in the fundamental theoretical and computational questions underlying robotic reconfiguration, in particular, questions such as what configurations are possible to achieve and how to plan for reconfiguration in a scalable manner. We leverage techniques from computational geometry and distributed algorithms to answer these questions, generating planning and controls methods for compliant reconfigurable robots that scale with the robot’s degrees of freedom.

Our current active projects include:

  • Distributed control for adaptive stiffness in parameterized origami structures in applications such as manipulation and legged locomotion
  • Geometric characterization of surfaces achievable using origami tessellations with straight and curved creases
  • Simulation and planning for modular trusses and lattices with tendon-driven control

Personnel: Jessica Weakly, Shivangi Misra

Selected Publications

Yuhong Qin*, Linda Ting*, Celestina Saven*, Yumika Amemiya, Michael Tanis, Randall Kamien, Cynthia Sung: TrussBot: Modeling, design and control of a compliant, helical truss of tetrahedral modules. IEEE International Conference on Robotics and Automation, 2022, (*=co-first author).
Xuan Li*, Jessica McWilliams*, Minchen Li, Cynthia Sung, Chenfanfu Jiang: Soft hybrid aerial vehicle via bistable mechanism. IEEE International Conference on Robotics and Automation (ICRA), 2021, (*=co-first author, best paper in mechanisms and design).
Tarik Tosun, Cynthia Sung, Colin McCloskey, Mark Yim : Optimal Structure Synthesis for Environment Augmenting Robots. In: IEEE Robotics and Automation Letters, vol. 4, no. 2, pp. 1069-1076, 2019.
Cynthia Sung, Daniela Rus: Foldable joints for foldable robots. In: ASME Journal of Mechanisms and Robotics, vol. 7, no. 2, pp. 021012, 2015.