A Low-Cost Soft Robotic Hand Exoskeleton for Use in Therapy of Limited Hand–Motor Function

We present the design and validation of a low-cost, customizable and 3D-printed anthropomorphic soft robotic hand exoskeleton for rehabilitation of hand injuries using remotely administered physical therapy regimens. The design builds upon previous work done on cable actuated exoskeleton designs by implementing the same kinematic functionality, but with the focus shifted to ease of assembly and cost effectiveness as to allow patients and physicians to manufacture and assemble the hardware necessary to implement treatment. The exoskeleton was constructed solely from 3D-printed and widely available of-the-shelf components. Control of the actuators was realized using an Arduino microcontroller, with a custom-designed shield to facilitate ease of wiring. Tests were conducted to verify that the range of motion of the digits and the forces exerted at the fingertip coincided with those of a healthy human hand

A Lightweight Modular Continuum Manipulator with IMU-based Force Estimation

Most aerial manipulators use serial rigid-link designs, which results in large forces when initiating contacts during manipulation and could cause flight stability difficulty. This limitation could potentially be improved by the compliance of continuum manipulators. To achieve this goal, we present the novel design of a compact, lightweight, and modular cable-driven continuum manipulator for aerial drones. We then derive a complete modeling framework for its kinematics, statics, and stiffness (compliance). The modeling framework can guide the control and design problems to integrate the manipulator to aerial drones. In addition, thanks to the derived stiffness (compliance) matrix, and using a low-cost IMU sensor to capture deformation angles, we present a simple method to estimate manipulation force at the tip of the manipulator. We report preliminary experimental validations of the hardware prototype, providing insights on its manipulation feasibility. We also report preliminary results of the IMU-based force estimation method.Comment: 12 pages, submitted to ASME Journal of Mechanisms and Robotics 2022, under review. arXiv admin note: substantial text overlap with arXiv:2206.0624

Design, implementation, and evaluation of a variable stiffness transradial hand prosthesis

We present the design, implementation, and experimental evaluation of a low-cost, customizable, easy-to-use transradial hand prosthesis capable of adapting its compliance. Variable stiffness actuation (VSA) of the prosthesis is based on antagonistically arranged tendons coupled to nonlinear springs driven through a Bowden cable based power transmission. Bowden cable based antagonistic VSA can, not only regulate the stiffness and the position of the prosthetic hand but also enables a light-weight and low-cost design, by the opportunistic placement of motors, batteries, and controllers on any convenient location on the human body, while nonlinear springs are conveniently integrated inside the forearm. The transradial hand prosthesis also features tendon driven underactuated compliant fingers that allow natural adaption of the hand shape to wrap around a wide variety of object geometries, while the modulation of the stiffness of their drive tendons enables the prosthesis to perform various tasks with high dexterity. The compliant fingers of the prosthesis add inherent robustness and flexibility, even under impacts. The control of the variable stiffness transradial hand prosthesis is achieved by an sEMG based natural human-machine interface

BRL/Pisa/IIT SoftHand:A Low-cost, 3D-Printed, Underactuated, Tendon-Driven Hand with Soft and Adaptive Synergies

This letter introduces the SRI/Pisa/HT (BPI) SoftHand: a single actuator-driven, low-cost, 3D-printed, tendondriven, underactuated robot hand that can be used to perform a range of grasping tasks. Based on the adaptive synergies of the Pisa/IIT SoftHand, we design a new joint system and tendon routing to facilitate the inclusion of both soft and adaptive synergies, which helps us balance durability, affordability and grasping performance of the hand. The focus of this work is on the design, simulation, synergies and grasping tests of this SoftHand. The novel phalanges are designed and printed based on linkages, gear pairs and geometric restraint mechanisms, and can be applied to most tendon-driven robotic hands. We show that the robot hand can successfully grasp and lift various target objects and adapt to hold complex geometric shapes, reflecting the successful adoption of the soft and adaptive synergies. We intend to open-source the design of the hand so that it can be built cheaply on a home 3D-printer

Anthropomorphically Inspired Design of a Tendon-Driven Robotic Prosthesis for Hand Impairments

This thesis presents the design of a robotic prosthesis, which mimics the morphology of a human hand. The primary goal of this work is to develop a systematic methodology that allows a custom-build of the prosthesis to match the specific requirements of a person with hand impairments. Two principal research questions are addressed toward this goal: 1) How do we cater to the large variation in the distribution of overall hand-sizes in the human population? 2) How closely do we mimic the complex morphological aspects of a biological hand in order to maximize the anthropomorphism (human-like appearance) of the robotic hand, while still maintaining a customizable and manageable design? This design approach attempts to replicate the crucial morphological aspects in the artificial hand (the kinematic structure of the hand skeleton, the shape and aspect ratios of various bone-segments, and ranges of motion). The hand design is partitioned into two parts: 1) A stiff skeleton structure, comprising parametrically synthesized segments that are simplified counterparts of nineteen bone-segments—five metacarpals, five proximal phalanges, four middle phalanges, and five distal phalanges—of the natural hand-skeleton and simplified mechanical substitutes of the remaining eight carpal bones. 2) A soft skin-like structure that encompasses the artificial skeleton to match the cosmetics and compliant features of the natural hand. A parameterized CAD model representation of each synthesized segment is developed by using the feature of design-tables in SolidWorks, which allows easy customization with respect to each person. Average hand measurements available in the literature are used to guide the dimensioning of parameters of each synthesized segment. Tendon-driven actuation of the fingers allows the servo actuators to be mounted remotely, thereby enabling a sleek finger design. A prototype of the robotic hand is constructed by 3D-printing all the parts using an Object 30 Prime 3D printer. Results reported from physical validation experiments of the robotic hand demonstrate the feasibility of the proposed design approach

Cost-Effective Prosthetic Hand for Amputees: Challenges and Practical Implementation

According to statistics, approximately 160,000 people in Malaysia, out of the current population of 32 million, need prosthetic or orthotic equipment. For individuals who have experienced upper extremity amputations, significant challenges are posed by the loss of functionality and the desire for a cosmetically appealing solution. To address this issue, a cost-effective prosthetic hand was proposed and developed. An overview of existing prosthetic hands is also offered, with an emphasis on cost-effectiveness, challenges, strengths, and weaknesses. The developed prosthetic hand incorporates a practical and underactuated finger mechanism. It is equipped with controllers based on EMG sensors to ensure that optimal responses are achieved during the grasping and releasing of objects. A suitable motor was carefully chosen to facilitate effective grasping and ungrasping activities. The proposed design was realized using SolidWorks and a 3D Printer. The capabilities of the prosthetic hand were demonstrated through a series of tests involving various objects, including pliers, a screwdriver, and a phone. The results indicate that objects of different sizes and shapes can be effectively grasped and ungrasped by the prosthetic hand. The unique bending angles in each finger result from the way tendons are connected via flexible cords and fishing lines to the servo motor. This design allows for a dynamic response based on the user's muscle flex and strength. The affordability of this cost-effective prosthetic hand demonstrates its potential as a practical and viable solution for amputees aiming to restore their grasping functionalities

Cost-Effective Prosthetic Hand for Amputees: Challenges and Practical Implementation

According to statistics, approximately 160,000 people in Malaysia, out of the current population of 32 million, need prosthetic or orthotic equipment. For individuals who have experienced upper extremity amputations, significant challenges are posed by the loss of functionality and the desire for a cosmetically appealing solution. To address this issue, a cost-effective prosthetic hand was proposed and developed. An overview of existing prosthetic hands is also offered, with an emphasis on cost-effectiveness, challenges, strengths, and weaknesses. The developed prosthetic hand incorporates a practical and underactuated finger mechanism. It is equipped with controllers based on EMG sensors to ensure that optimal responses are achieved during the grasping and releasing of objects. A suitable motor was carefully chosen to facilitate effective grasping and ungrasping activities. The proposed design was realized using SolidWorks and a 3D Printer. The capabilities of the prosthetic hand were demonstrated through a series of tests involving various objects, including pliers, a screwdriver, and a phone. The results indicate that objects of different sizes and shapes can be effectively grasped and ungrasped by the prosthetic hand. The unique bending angles in each finger result from the way tendons are connected via flexible cords and fishing lines to the servo motor. This design allows for a dynamic response based on the user's muscle flex and strength. The affordability of this cost-effective prosthetic hand demonstrates its potential as a practical and viable solution for amputees aiming to restore their grasping functionalities

A New Approach of Soft Joint Based on a Cable-Driven Parallel Mechanism for robotic Applications

A soft joint has been designed and modeled to perform as a robotic joint with 2 Degrees of Freedom (DOF) (inclination and orientation). The joint actuation is based on a Cable-Driven Parallel Mechanism (CDPM). To study its performance in more detail, a test platform has been developed using components that can be manufactured in a 3D printer using a flexible polymer. The mathematical model of the kinematics of the soft joint is developed, which includes a blocking mechanism and the morphology workspace. The model is validated using Finite Element Analysis (FEA) (CAD software). Experimental tests are performed to validate the inverse kinematic model and to show the potential use of the prototype in robotic platforms such as manipulators and humanoid robots.The research leading to these results has received funding from the project Desarrollo de articulaciones blandas para aplicaciones robóticas, with reference IND2020/IND-1739, funded by the Comunidad Autónoma de Madrid (CAM) (Department of Education and Research), and from RoboCity2030-DIH-CM, Madrid Robotics Digital Innovation Hub (Robótica aplicada a la mejora de la calidad de vida de los ciudadanos, FaseIV; S2018/NMT-4331), funded by Programas de Actividades I+D en la Comunidad de Madrid and cofunded by Structural Funds of the EU

Advancing the Underactuated Grasping Capabilities of Single Actuator Prosthetic Hands

The last decade has seen significant advancements in upper limb prosthetics, specifically in the myoelectric control and powered prosthetic hand fields, leading to more active and social lifestyles for the upper limb amputee community. Notwithstanding the improvements in complexity and control of myoelectric prosthetic hands, grasping still remains one of the greatest challenges in robotics. Upper-limb amputees continue to prefer more antiquated body-powered or powered hook terminal devices that are favored for their control simplicity, lightweight and low cost; however, these devices are nominally unsightly and lack in grasp variety. The varying drawbacks of both complex myoelectric and simple body-powered devices have led to low adoption rates for all upper limb prostheses by amputees, which includes 35% pediatric and 23% adult rejection for complex devices and 45% pediatric and 26% adult rejection for body-powered devices [1]. My research focuses on progressing the grasping capabilities of prosthetic hands driven by simple control and a single motor, to combine the dexterous functionality of the more complex hands with the intuitive control of the more simplistic body-powered devices with the goal of helping upper limb amputees return to more active and social lifestyles. Optimization of a prosthetic hand driven by a single actuator requires the optimization of many facets of the hand. This includes optimization of the finger kinematics, underactuated mechanisms, geometry, materials and performance when completing activities of daily living. In my dissertation, I will present chapters dedicated to improving these subsystems of single actuator prosthetic hands to better replicate human hand function from simple control. First, I will present a framework created to optimize precision grasping – which is nominally unstable in underactuated configurations – from a single actuator. I will then present several novel mechanisms that allow a single actuator to map to higher degree of freedom motion and multiple commonly used grasp types. I will then discuss how fingerpad geometry and materials can better grasp acquisition and frictional properties within the hand while also providing a method of fabricating lightweight custom prostheses. Last, I will analyze the results of several human subject testing studies to evaluate the optimized hands performance on activities of daily living and compared to other commercially available prosthesis

Biologically Inspired Legs and Novel Flow Control Valve Toward a New Approach for Accessible Wearable Robotics

The Humanoid Walking Robot (HWR) is a research platform for the study of legged and wearable robots actuated with Hydro Muscles. The fluid operated HWR is representative of a class of biologically inspired, and in some aspects highly biomimetic robotic musculoskeletal appendages showing certain advantages in comparison to more conventional artificial limbs and braces for physical therapy/rehabilitation, assistance of daily living, and augmentation. The HWR closely mimics the human body structure and function, including the skeleton, ligaments, tendons, and muscles. The HWR can emulate close to human-like movements even when subjected to simplified control laws. One of the main drawbacks of this approach is the inaccessibility of an appropriate fluid flow management support system, in the form of affordable, lightweight, compact, and good quality valves suitable for robotics applications. To resolve this shortcoming, the Compact Robotic Flow Control Valve (CRFC Valve) is introduced and successfully proof-of-concept tested. The HWR added with the CRFC Valve has potential to be a highly energy efficient, lightweight, controllable, affordable, and customizable solution that can resolve single muscle action