Robotic forearm orthosis using soft fabric-based helical actuators

A robotic orthosis, comprising:

• a user mounting system configured to attach to a user's forearm;
• a first helical actuator comprising:
• a first cylinder having a first longitudinal axis, the first cylinder comprising:
• a first anisotropic sheet material comprising elastomeric strands, wherein all the elastomeric strands are oriented in a first direction and the first direction is different than the first longitudinal axis;
• a base sheet material affixed to the first anisotropic sheet material, wherein the base sheet material is strain-limiting along the longitudinal axis;
• wherein the first anisotropic sheet material is more extendible in a first extension direction along the longitudinal axis than the base sheet material;
• and
• a first bladder disposed within the first cylinder, the first bladder comprising:
• an inlet configured to receive a working fluid;
• and an outlet configured to expel working fluid;
• wherein the first bladder is configured to inflate and apply pressure against the first cylinder and rotate the first cylinder in a first rotation direction about the first longitudinal axis;
• and
• a second helical actuator, comprising:
• a second cylinder having a second longitudinal axis, the second cylinder comprising a second anisotropic sheet material comprising elastomeric strands, wherein all the elastomeric strands of the second anisotropic sheet are oriented in a second direction and the second direction is different than the second longitudinal axis, wherein the second anisotropic sheet material is affixed to a second base sheet material;
• wherein the second anisotropic sheet material is more extendible in a second extension direction along the second longitudinal axis than the second base sheet material;
• and
• a second bladder disposed within the second cylinder;
• wherein the second bladder is configured to inflate and apply pressure against the second cylinder and rotate the second cylinder about the second longitudinal axis in a second rotation direction opposite the first rotation direction relative to the first cylinder.

A fabric-based helical actuator, comprising:

• a first cylinder having a longitudinal axis, the first cylinder comprising:
• a first anisotropic sheet material comprising a matrix and a first set of elastomeric strands, wherein the first set of elastomeric strands are embedded in the matrix and all the elastomeric strands are oriented in a first direction and the first direction is different than the longitudinal axis;
• and
• a base sheet material affixed to the first anisotropic sheet material, wherein the base sheet material is strain-limiting along the longitudinal axis, whereby the first anisotropic sheet material is more extendible in a first extension direction along the longitudinal axis than the base sheet material;
• a first bladder disposed within the first cylinder, wherein the first bladder is configured to inflate and apply pressure against the first cylinder, wherein pressure against the first cylinder by the first bladder causes the first cylinder to rotate in a first rotation direction;
• a second cylinder comprising a second anisotropic sheet material affixed to a second base sheet material, the second anisotropic sheet material comprising a second set of elastomeric strands;
• and
• a second bladder disposed within the second cylinder, wherein the second bladder is configured to inflate and apply pressure against the second cylinder, wherein pressure against the second cylinder by the second bladder causes the second cylinder to rotate in a second rotation direction.