Biomedical and Patient Care

Soft Cardiac Assist Devices

We are developing an entirely soft, fluid pumping device. Our pump is comprised of biocompatible materials and leverages elastomer foam in its inflation chambers. When these chambers are inflated with compressed air, an adjacent water-containing chamber is pressurized which generates flow. Our pump design uses two isolated foam inflation chambers. By alternating inflation of the chambers, we observe controlled pulsatile, unidirectional flow. We believe that, with further development, this device could find use as a ventricular assist device (VAD). Though this pump was molded to reflect the geometry of a human heart, it could function equally well in a variety of other shapes.
  • Generates up to 430 ml/min flow.
  • Pumps at physiological pressures (~105 mm Hg) and frequencies (60 – 120 BPM).
Relevant Publications:

Soft Orthotic Actuators

We applied rotational casting as a reliable and effective method for fabricating high force orthotics. We fabricated a wearable assistive device for increasing the force a user can apply at their fingertips. To better improve the functionality of the hand orthotics, we also demonstrated the monolithic integration of solid-state optical light-guides for curvature sensing in them. Besides fabrication and integration, we have also realized feedback control of FEAs using the embedded sensors.
  • Relatively large applied forces at finger tip.
  • Safe human-machine interaction.
Relevant Publications:

Curvature Control of Soft Orthotics via Low Cost Solid-State Optics

We have developed a new method to embed low-cost, PDMS-based optical fibers into pneumatically actuated orthotic hands that enable enhanced feedback and control.
  • A soft orthotic hand fabricated using rotational casting and overmolding.
  • Static and dynamic states are monitored via the modified optical-fiber sensors.
  • Prescribed curvatures are achieved through valve controlling.
Relevant Publications:

Dielectric Elastomer Sensors (DESs)

Capacitors fabricated from soft materials give us the opportunity to design pressure sensitive skins for robots. In this work, we 3D printed these capacitors on top of pneumatic actuators. These sensors allow soft robots to feel external touch and their own shape.
  • Direct ink write 3D printing can be used to draw these sensors onto the skin of pneumatic actuators.
  • These sensors do not delaminate even under the large deformations of the underlying pneumatic actuators.
  • We were able to use these sensors to create a programmable, haptic interface with potential for use in prosthetics.
Relevant Publications: