HBS-1.2: Lightweight Socially Assistive Robot with 6-Ply Twisted Coiled Polymer Muscle-Actuated Hand

Singh, Abhishek; Palani, Dharmendran; Ahmed, O.A.; Matharu, Pawandeep Singh; Linn, Thomas; Nguyen, Trung; Tadesse, Yonas

doi:10.3390/act12080312

Cited by 3 publications

(1 citation statement)

References 50 publications

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“…An inherent challenge in EEG-and EMGcontrolled orthotic hands, compared to mobile app-controlled servo motors, is fine tuning and precise controlling that impacts the intricacy of certain movements. Overall, these technological advancements hold promise for improving the quality of life and mobility of individuals with neurological and upper limb impairments [43][44][45][46][47][48].…”

Section: Introductionmentioning

confidence: 99%

NOHAS: A Novel Orthotic Hand Actuated by Servo Motors and Mobile App for Stroke Rehabilitation

Selvaraj Mercyshalinie,

Ghadge,

Ifejika

et al. 2023

Robotics

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The rehabilitation process after the onset of a stroke primarily deals with assisting in regaining mobility, communication skills, swallowing function, and activities of daily living (ADLs). This entirely depends on the specific regions of the brain that have been affected by the stroke. Patients can learn how to utilize adaptive equipment, regain movement, and reduce muscle spasticity through certain repetitive exercises and therapeutic interventions. These exercises can be performed by wearing soft robotic gloves on the impaired extremity. For post-stroke rehabilitation, we have designed and characterized an interactive hand orthosis with tendon-driven finger actuation mechanisms actuated by servo motors, which consists of a fabric glove and force-sensitive resistors (FSRs) at the tip. The robotic device moves the user’s hand when operated by mobile phone to replicate normal gripping behavior. In this paper, the characterization of finger movements in response to step input commands from a mobile app was carried out for each finger at the proximal interphalangeal (PIP), distal interphalangeal (DIP), and metacarpophalangeal (MCP) joints. In general, servo motor-based hand orthoses are energy-efficient; however, they generate noise during actuation. Here, we quantified the noise generated by servo motor actuation for each finger as well as when a group of fingers is simultaneously activated. To test ADL ability, we evaluated the device’s effectiveness in holding different objects from the Action Research Arm Test (ARAT) kit. Our device, novel hand orthosis actuated by servo motors (NOHAS), was tested on ten healthy human subjects and showed an average of 90% success rate in grasping tasks. Our orthotic hand shows promise for aiding post-stroke subjects recover because of its simplicity of use, lightweight construction, and carefully designed components.

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Section: Introductionmentioning

confidence: 99%

NOHAS: A Novel Orthotic Hand Actuated by Servo Motors and Mobile App for Stroke Rehabilitation

Selvaraj Mercyshalinie,

Ghadge,

Ifejika

et al. 2023

Robotics

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Single layered soft skin actuated with twisted and mandrel coiled actuators for soft robotics

Matharu,

Singh,

Song

et al. 2024

Journal of Polymer Science

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Soft silicone‐based artificial skin is essential in soft robotics because of high elongation, safe human interaction, low energy requirements and ease of manufacturing. Inspired by nature, several attempts have been made to fabricate morphing structures using synthetic soft skin. In this study, a novel elastomeric skin is demonstrated featuring embedded actuators and micro‐fluidic channels, that is capable of grasping objects. The actuators are twisted, and mandrel coiled nylon artificial muscles, with nichrome heaters that overcome key challenges in developing synthetic soft skin. The desired properties of a morphing skin are being low‐cost, lightweight, highly deformable, compact size, silent cyclic actuation, fast response, and long life. The actuators are fabricated from 160 μm diameter resistance wires wrapped on twisted nylon 6 fishing line precursor fibers of 800 μm diameter. The wrapped nichrome (0.42 mm pitch) along with the twisted precursor fibers are coiled on a 1.4 mm diameter mandrel rod to obtain high strain. This muscle termed twisted, and mandrel coiled polymer fishing line muscle with nichrome is embedded in soft skin samples and tested. Characterization results on the actuators (3.2 mm in diameter) showed remarkable tensile actuation of ~36% strain from loaded length at 0.99 MPa for an input power of 4.9 W, a blocked stress of 1.27 MPa, an actuation frequency of 0.04 Hz, and a lifecycle >22,000 cycles. These actuators, when embedded in the soft skin of 4 mm thick, showed ~50% bending strain within 10s and a cyclic behavior with active water cooling. A soft gripper fabricated with embedded soft skin is integrated to our child‐sized humanoid robot (HBS Robot) demonstrating its potential in grasping unconventional and deformable objects, hence advancing the progress in soft robotics.

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Multi-layered morphing soft structure with high-performance embedded electrothermal artificial muscles along with touch and temperature sensors

Singh Matharu,

Song,

Gandhi

et al. 2024

Smart Mater. Struct.

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In this paper, we present a novel multilayered morphing structure, having similar topology resembling the structures found in nature to grasp delicate objects effectively as well as sense contact force and temperature. The structure consists of two actuation layers, two U-shaped cooling channel layers, piezoelectric based touch sensors and temperature sensors. Employing shape memory alloy (SMA) spring actuators for bending and twisted and coiled polymer fishing line with nichrome (TCPFLNMC) artificial muscles for antagonistic return, the soft silicone-based composite skin exhibits unique capabilities of large bidirectional movement, avoid rigid passive springs for return motion, soft grasping, safe interaction with humans, and ease fabrication. The SMA (0.38 mm wire diameter) serves as relatively fast actuating muscle and the TCPFLNMC (0.8 mm fiber diameter) as a slow actuating (considering mainly heating cycle), which was programmed/designed to mimic the fast and slow twitching muscles found in nature. Bending and return operations of skin samples of length 100 mm and thickness of 9 mm, with three different widths 20 mm, 25 mm, 30 mm, were experimentally studied. The 25 mm wide multilayered soft skin demonstrated cyclic actuation with a maximum bending angle of ~70°, which was attributed due to the active cooling. The fluidic channels for active cooling were fabricated using 3D printed PVA tubes, casting within the silicone in a mold and subsequently dissolving in a circulating water. The study also included the integration and voltage response of mini-piezodisk sensor PIC255 having a diameter of 2 mm and thickness of 0.15 mm, which was embedded at different depths within the silicone (on the surface, 1 mm depth and 2 mm depth). The multilayered soft skin was also able to detect the temperature of the object during grasping, suggesting its potential application as a soft gripper in robotic systems.

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HBS-1.2: Lightweight Socially Assistive Robot with 6-Ply Twisted Coiled Polymer Muscle-Actuated Hand

Cited by 3 publications

References 50 publications

NOHAS: A Novel Orthotic Hand Actuated by Servo Motors and Mobile App for Stroke Rehabilitation

NOHAS: A Novel Orthotic Hand Actuated by Servo Motors and Mobile App for Stroke Rehabilitation

Single layered soft skin actuated with twisted and mandrel coiled actuators for soft robotics

Multi-layered morphing soft structure with high-performance embedded electrothermal artificial muscles along with touch and temperature sensors

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