State-of-the-Art of Hand Exoskeleton Systems

This paper deals with the analysis of the state-of-the-art of robotic hand exoskeletons (updated at May 2011), which is intended as the first step of a designing activity. A large number of hand exoskeletons (both products and prototypes) that feature some common characteristics and many special peculiarities are reported in the literature. Indeed, in spite of very similar functionalities, different hand exoskeletons can be extremely different for the characteristics of their mechanism architectures, control systems and working principles. The aim of this paper is to provide the reader with a complete and schematic picture of the state-of-the-art of hand exoskeletons. The focus is placed on the description of the main aspects that are involved in the exoskeleton design such as the system kinematics, the actuator systems, the transmission parts and the control schemes. Additionally, the critical issues provided by the literature analysis are discussed in order to enlighten the differences and the common features of different practical solutions. This paper may help to understand both the reasons why certain solutions are proposed for the different applications and the advantages and drawbacks of the different designs proposed in the literature. The motivation of this study is the need to design a new hand exoskeleton for rehabilitation purposes

LineFORM: Actuated Curve Interfaces for Display, Interaction, and Constraint

In this paper we explore the design space of actuated curve interfaces, a novel class of shape changing-interfaces. Physical curves have several interesting characteristics from the perspective of interaction design: they have a variety of inherent affordances; they can easily represent abstract data; and they can act as constraints, boundaries, or borderlines. By utilizing such aspects of lines and curves, together with the added capability of shape-change, new possibilities for display, interaction and body constraint are possible. In order to investigate these possibilities we have implemented two actuated curve interfaces at different scales. LineFORM, our implementation, inspired by serpentine robotics, is comprised of a series chain of 1DOF servo motors with integrated sensors for direct manipulation. To motivate this work we present various applications such as shape changing cords, mobiles, body constraints, and data manipulation tools

Haptic Hand Exoskeleton for Precision Grasp Simulation

This paper outlines the design and the development of a novel robotic hand exoskeleton (HE) conceived for haptic interaction in the context of virtual reality (VR) and teleoperation (TO) applications. The device allows exerting controlled forces on fingertips of the index and thumb of the operator. The new exoskeleton features several design solutions adopted with the aim of optimizing force accuracy and resolution. The use of remote centers of motion mechanisms allows achieving a compact and lightweight design. An improved stiffness of the transmission and reduced requirements for the electromechanical actuators are obtained thanks to a novel principle for integrating speed reduction into torque transmission systems. A custom designed force sensor and integrated electronics are employed to further improve performances. The electromechanical design of the device and the experimental characterization are presented

Design, characterisation and validation of a haptic interface based on twisted string actuation.

This paper presents the design and experimental characterisation of a wrist haptic interface based on a twisted string actuator. The interface is designed for controlled actuation of wrist flexion/extension and is capable of rendering torque feedback through a rotary handle driven by the twisted string actuator and spring-loaded cable mechanisms. The interface was characterised to obtain its static and dynamic haptic feedback rendering capabilities. Compliance in the spring and actuation mechanism makes the interface suitable for smooth rendering of haptic feedback of large magnitudes due to the high motion transmission ratio of the twisted strings. Haptic virtual wall rendering capabilities are demonstrated

Handheld Haptic Device with Coupled Bidirectional Input

Handheld kinesthetic haptic interfaces can provide greater mobility and richer tactile information as compared to traditional grounded devices. In this paper, we introduce a new handheld haptic interface which takes input using bidirectional coupled finger flexion. We present the device design motivation and design details and experimentally evaluate its performance in terms of transparency and rendering bandwidth using a handheld prototype device. In addition, we assess the device's functional performance through a user study comparing the proposed device to a commonly used grounded input device in a set of targeting and tracking tasks.Comment: 7 pages, 7 figures, World Haptics Conference 2023 Preprin

Towards a Twisted String Actuated Haptic Device: Experimental Testing of a 2-D Virtual Environment and Teleoperation Interface

In the article, a first stage implementation of a haptic device towards a complete 3-D workspace twisted-string actuated haptic interface is discussed. In the present work, a 2-D setup is presented, with the aim of preliminarly testing the behaviour of this novel haptic system, especially with respect to the adopted cable-based actuation solution. In particular, the component descriptions, kinematics of the planar device and the controller for teleoperation purposes are illustrated. Results regarding the behaviour of the system in rendering a virtual environment and in a robot teleoperation scenario with haptic force feedback are reported. The experimental outcomes show that the designed and implemented system is suitable for teleoperation with haptic interfaces, providing positive perspectives for the realization of the fully functional 3-D haptic interface in the future work