Introduction: Soft Robotics Glove

My project is a softrobotic glove. It has an actuator positioned on each finger; the bottom part of the glove is removed to facilitate the user to wear it. The actuators are activated by a device positioned on the wrist a little bigger than a watch.

The actuators are made out of a silicon material (EcoFlex-30) and are inflatable.

As the actuators inflate, the rectangles they have on their top push against each other, bending the associated fingers.

The motor that controls the inflation is a device called "FlowIO". This device is able to inflate, to deflate and to create a vacuum. At this moment the device is using an Adafruit platform controlled by an app on my phone, but my aim is to associate it with another glove with flex-sensors on its fingers, so that the softglove's movements would mirror the other's ones.

This project has a rehabilitation purpose, for patients who had lost of a hand. The moving of the softglove reactivates the muscles of the injured hand, while the two hands doing the same movements stimulates mirror neurons, recreating neural connections in the brain.

This project can also be used as Assistive Technology purposes, as it is easy to wear and the actuators guarantees good grasps on objects.

While working on this project you will learn about the elastic proprieties of materials, how to cast silicon, how to use TinkerCad and 3D printers.


      Step 1: 3D Printing the Molds

      • Each of these files contains the three pieces necessary for a finger.
      • High quality (0.001mm at least) is suggested for the print.
      • It's not needed to build a support, but is suggested to build a raft as platform of adhesion.

      Step 2: Preparing the Molds

      1. Attach two molds one on top of the other as shown in the image.
      2. Seal those with hot glue in the space in between them.
      3. Stick a nail in the hole in the side of those molds and glue it on the outside using hotglue.
      4. Spray the molds with the Easy Release agent, two times with a 5 minutes interval in between.

      Step 3: Preparing the Silicon

      1. Pour the two component of EcoFlex in two different plastic glasses. They have to be of the same weight, use the scale to measure them.
      2. Pour one of the component into the other glass and mix them carefully for three minutes.
      3. Put the glass inside the vacuum chamber and start degassing. Once the pressure inside reaches -25atm reopen the valve and turn off the vacuum, until it gets to -20atm. Then close the valve and reactivate the vacuum. These process has to be repeated for 10 minutes.
      4. Take out the glass from the camber.

      Step 4: Pouring the Silicon

      1. Pour the silicon from the glass to the molds, paying attention not to create bubbles of air inside.
      2. After five minutes pass a wooden stick, kept horizontal, over the two molds, in order to remove the silicon in excess.
      3. Leave the silicon to solidify for three hours.

      Step 5: Extracting the Actuators

      For composed molds

      1. Remove the layer of hot glue.
      2. Carefully separate the two molds, keeping them the most parallel to each other during the process.
      3. The top piece of the actuator will almost every time remain in the top mold. At this point extract the top piece of the actuator just pulling it out, but paying attention not to brake or damage it

      For single molds

      1. Just extract the bottom piece of the actuator from the mold.

      Step 6: Finalizing the Actuators

      1. Remove the external layer of silicon on the base of the top mold
      2. Spread a thin layer of Sil-Poxy on the bottom pieces. If possible, the glue should be more concentrated on the sides of the rectangles than in the middle. Use the side of a plastic coated card
      3. Place the top piece on top of the bottom piece. Keep pushing the two pieces gently together, for at least seven minutes.
      4. Leave the actuators for 40 minutes, to let the glue to cure.
      5. Cut 10cm pieces from the plastic tube. Insert each of these pieces in the hole on the side of each actuators. Seal them with Sil-Poxy

      In alternative

      If you have some precise instruments at your disposal to displace the glue, it is preferable to spread it on the bottom side of the to part of the actuators.

      Step 7: Finalizing the Project

      1. Spread a layer of Sil-Poxy on the bottom part of the actuators.
      2. Attach each actuator, one at the time, on the relative finger of the electrician glove, keeping it pressed for at least seven minutes and waiting for the glue to cure for 40 minutes.
      3. Secure the FlowIO on the wrist or on the forearm.
      4. Cut the palm section of the glove, and possibly also the inside of the first phalanx of each finger, in order to facilitate its wearing
      5. Wear the glove.
      6. Connect each plastic tube to its relative valve on the FlowIO.

      NOTE: If it's not possible for you to get a FlowIO device, this project is compatible with any kind of air pump.

      Step 8: Enjoy the Glove!

      Use the app on your iPhone to start using your device.

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