Design of fiber-reinforced soft bending pneumatic artificial muscles for wearable tremor suppression devices

Abstract

Soft robotics is a rapidly evolving field offering novel solutions in the development of wearable technologies. Soft pneumatic artificial muscles in particular, have seen widespread use in the development of human scale rehabilitative and assistive wearables. However, these soft actuators have not yet been adapted to address the complex dynamic regime of active (essential tremor) and resting (Parkinson’s disease) hand tremor, the most common movement disorder affecting humans. Current solutions to address hand tremor involve expensive medication and surgical interventions, as well as wearable assistive devices that fall short of providing an effective compact design for the suppression of hand tremor. This study focuses on the design of a novel lightweight, compact, bending actuator that will be capable of actively suppressing hand tremor when adapted into an assistive wearable device. The proposed fiber-reinforced bending pneumatic artificial muscle (BPAM), including its design specifications, fabrication process, theoretical modeling, and experimental characterization, are detailed. The developed actuator was capable of producing sinusoidal trajectories with peak-to-peak amplitudes of 40° and a bandwidth of 8 Hz, the dynamic regime of pathological hand tremor. The ability of the fiber-reinforced BPAM to act within the dynamic regime of hand tremor demonstrates its potential to be further developed into a system capable of the active suppression of hand tremor.

4D printing of soft orthoses for tremor suppression

“…In 2020, Wirekoh et al proposed a hand tremor attenuator with fiber-reinforced bending pneumatic artificial muscle (BPAM) and fabricated it in a finger-scale size [60]. The prototype has good flexibility to move in a 40-degree peakto-peak range at frequencies between 4 and 8 Hz (normal frequency for PD and essential tremor) [60]. In 2021, Skaramagkas et al constructed another hand tremor suppressor orthosis (Fig.…”

“…The two common soft actuator types used to produce bio-assistant devices are pneumatic [103] and hydraulic [104]. Wirekoh et al developed a fiberreinforced bending pneumatic artificial muscle specifically to suppress finger tremors [60]. With recent advancements in 3D/4D printing, it has become possible to fabricate soft pneumatic (Fig.…”

Power-Efficient Soft Pneumatic Actuator Using Spring-Frame Collateral Compression Mechanism

“…In addition, their high force-to-weight ratio makes them a strong candidate for safe humanrobot interactive tasks due to the minimization of the mass and inertia of the end-effector of robots [10]. Owing to these unique characteristics, soft PAMs have potential in the field soft robots [11][12][13].…”

Pneumatic Artificial Muscle Based on Novel Winding Method

“…By limiting the movement of one side of the silicone tube, the other side rotates around the limiting surface. Such structure is often used for hand assistance [20,21]. Because the expansion of the side close to the finger is limited, the bending type will not squeeze the finger when assisting the human movement [21], hence combining with inherent compliance, the structure has great human compatibility.…”