A Soft 3D-Printed Robotic Hand Actuated by Coiled SMA

Abstract

Robotic hands with unique designs, capabilities and applications have been presented in the literature focusing on sensing, actuation, control, powering and manufacturing, most of which are created by manual assembly process. However, due to advancements in additive manufacturing, new capabilities have replaced traditional methods of manufacturing. In this paper, we present a soft 3D-printed robotic hand actuated by custom-made coiled shape memory alloy (SMA) actuators. The hand uses additive manufacturing of flexible thermoplastic polyurethane (TPU) material, which allows flexing at the joint and hence eliminates the need for additional assembly. Here, we present the full characteristics of the robotic hand such as object grasping categorized by size and weight from the ARAT kit and others. The robotic hand is 425 mm in length, weighs 235 g and is able to operate at a frequency of 0.125 Hz without active cooling. It can grasp an object of 55–81 mm widths, weighing up to 133 g, while consuming an average power of 7.82 W. We also show the time domain response of our custom-made coiled SMA to different current inputs, and its corresponding force and displacement. The current design yields a lightweight and low cost artificial hand with significantly simplified manufacturing for applications in robotics and prosthetics.

Cooling‐Accelerated Nanowire‐Nitinol Hybrid Muscle for Versatile Prosthetic Hand and Biomimetic Retractable Claw

“…Although there have been several interesting prosthetic hands developed based on soft artificial muscles, slow actuation speed of the prosthetic hand was always discussed as must-be-solved issue, especially for those fabricated using artificial muscles that actuate under thermomechanical principle. [50][51][52][53][54][55][56][57][58] As of that matter, cooling-accelerated CuNF-SMAc is a newly suggested effective method to solve the issue, as the prosthetic hand we prepared successfully showed the fastest actuation among previous prosthetic hands reported (Table S2, Supporting Information). Particularly, potential usage of SMA based artificial muscle was expanded to a prosthetic hand which can perform more diverse functions then previously reported, by introducing the fast-cooling CuNF-SMAc.…”

4D printing of soft orthoses for tremor suppression

“…Shape memory alloys (SMAs) have been utilized in a flexible wearable actuator for hand tremor suppression [113,114]. Shape memory polymers (SMPs) have significantly contributed to the 4D printing of soft wearable actuators [115], yielding a high recovery rate of 96% [116]. In addition, the integration of SMA and SMP with multi-material printing [117] has resulted in a soft robotic hand, which was reported to work at 0.125 Hz without active cooling and capable of handling heavy objects up to 133 g [118].…”

Twisted and coiled polymer muscle actuated soft 3D printed robotic hand with Peltier cooler for drug delivery in medical management

“…TPU is a flexible material that can provide strength in higher thicknesses and toughness and flexibility in lower thicknesses. This hand was previously utilized in combination with other artificial SMA muscles [15]. So, this is adequate to test the TCPFL muscles used in the design presented in this paper.…”