Modeling Vacuum Bellows

“Vacuum bellows” are membrane-reinforced contractile actuators that are subjected to negative internal gauge pressures. Though a popular research topic at the moment, the ideas behind these actuators are ancient. My work explored the effect of ring spacing on the actuator performance. My model reveals that by spacing the rings far apart, it is possible to achieve forces many times greater than an equivalent-diameter vacuum cylinder at the same pressure.

Related Publications

  • Felt, W., Robertson, M.A. and Paik, J., 2018, “Modeling Vacuum Bellows Soft Pneumatic Actuators with Optimal Mechanical Performance”, Soft Robotics (RoboSoft 2018), 2018 IEEE-RAS International Conference on, [Preprint]

Sensing the Motion of Bellows-driven Joints via Inductance

The inductance sensing techniques I developed for fiber-reinforced soft actuators can also be applied to soft pneumatic bellows. Working with Pneubotics, I demonstrated inductance sensing on a unique bellows-driven continuum joint. The paper was a finalist for the Best Systems Paper at Robotics: Science & Systems 2017.

I developed inductance sensing techniques for the continuum joints of this bellows-driven robot. Image Credit: Pneubotics

Related Publications

  • Felt, W., Telleria, M.J., Allen, T., Hein, G., Pompa, J., Albert, K., Remy, C.D., 2018, “An inductance-based sensing system for bellows-driven continuum joints in soft robots”, Autonomous Robotics (In Press, extension of RSS version)
  • Felt, W., 2017,”Sensing Methods for Soft Robotics,”, PhD Thesis, [URL]
  • Felt, W., Telleria, M.J., Allen, T., Hein, G., Pompa, J., Albert, K., Remy, C.D., 2017, “An inductance-based sensing system for bellows-driven continuum joints in soft robots”, Robotics: Science and Systems (RSS), Cambridge, MA [URL]
  • Felt, W., Suen, M., and Remy, C.D., 2016, “Sensing the motion of bellows through changes in mutual inductance”, International Conference on Intelligent Robots and Systems (IROS), Daejeon, South Korea [URL]

New Closed-Form Kinematic Model for Fiber-Reinforced Elastomeric Enclosures (FREEs)

Fiber-Reinforced Elastomeric Enclosures or FREEs are a class of cylindrical soft pneumatic actuators that can rotate as they contract or extend. Previous descriptions of these actuators were unwieldy and required complex iterative evaluations to predict the kinematic behavior. The model I developed dramatically simplifies the description of the actuators into a closed-form kinematic model with three design parameters and one state.

Related Publications

  • Felt, W. and Remy, C.D., 2018, “A closed-form kinematic model for Fiber Reinforced Elastomeric Enclosures”, Journal of Mechanisms and Robotics  [URL]
  • Felt, W., Lu, S., Remy, C.D., 2018, “Modeling and design of “Smart Braid” inductance sensors for fiber-reinforced elastomeric enclosures”, IEEE Sensors Journal, [URL]
  • Felt, W., 2017,”Sensing Methods for Soft Robotics,”, PhD Thesis, [URL]

“Smart Braids” for Self-Sensing Fiber Reinforced Soft Actuators

By using an electrical circuit of flexible wires to reinforce a soft actuator, the length of the actuator can be measured through the inductance of the circuit.

My “Smart Braid” inductance sensing technique for McKibben muscles was awarded the 2015 Prize for the Contributions in Soft Robotics Research (Soft Robotics Toolkit). See the paper here.

Publications

  • Felt, W., 2017,”Sensing Methods for Soft Robotics,”, PhD Thesis, [URL]

  • Felt, W., Lu, S., Remy, C.D., 2018, “Modeling and design of “Smart Braid” inductance sensors for fiber-reinforced elastomeric enclosures”, IEEE Sensors Journal, [URL]

  • Felt, W., Chin, K.Y., and Remy, C.D., 2017, “Smart Braid feedback for the closed-loop control of soft robotic systems”, Soft Robotics, 4(3):261-273 [URL]

  • Felt, W., Chin, K.Y., and Remy, C.D., 2015, “Contraction sensing with Smart Braid McKibben muscles”, IEEE/ASME Transactions on Mechatronics, 21(3):1201-2019 [URL]

  • Felt, W. and Remy, C.D., 2014, “Smart Braid: Air muscles that measure force and displacement”, International Conference on Intelligent Robots and Systems (IROS), Chicago, IL [URL]

Body-in-the-Loop Optimization

metop_previewWorking with my PhD advisor, C. David Remy, I pioneered the use of real-time measurements of metabolic cost to drive the online optimization of human assistance devices. The methods described in our early work have been adapted and used by some of the top researchers in human motion assistance.

My work inspired and enabled work by:

Steve Collins (Stanford)                                     Zhang et al. Science 2017.
Conor Walsh (Harvard)                                      Kim, Ding, et al. PLOS One 2017
” ”                                                                       Ding,  Kim et al. Science Robotics 2018
David Remy and Dan Ferris (U. of Michigan)    Koller et al. RSS 2016
” ”                                                                       Koller et al. Jrnl of Appl. Physiology 2017

Related Publications

Journal Paper

  • Felt, W., Selinger, J., Donelan, J.M., and Remy, C.D., 2015, “”Body-In-The-Loop”: Optimizing Device Parameters Using Measures of Instantaneous Energetic Cost”, PLOS ONE, 10(8):e0135342 [URL]

Conference Presentations and Posters

  • Felt, W., Gardinier, E.S., Wensman, J., Gates, D.H., and Remy, C.D., 2015, “Body-in-the-Loop Optimization for the Selection of Prosthetic Control Parameters–A Pilot Study”, American Society of Biomechanics Annual Meeting [preprint]
  • Felt, W., Selinger, J., Donelan, J.M., and Remy, C.D., 2014, ” Body-in-the-Loop — Optimizing Actual Human Walking”, Dynamic Walking [preprint]

  • Gardinier, E.S., Felt, W., Wensman, J., Remy, C.D., and Gates, D.H., 2015, “Compensations Exist in Persons with Transtibial Ampuatation using Powered Ankle Prosthesis”, American Society of Biomechanics Annual Meeting [preprint]

  • Davidson, A., Gardinier, E.S., Felt, W., Wensman, J., Remy, C.D., and Gates, D.H., 2015, “Changes in Metabolic Cost with Varying Power Settings of a Powered Ankle Prosthesis”, American Society of Biomechanics Annual Meeting [preprint]