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

Abstract

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.

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

“…These benefits include inherent compliance, low weight, flexibility in cable routing, and comparatively high efficiency. Several implementations for TSA-based robotic exoskeletons have been described recently for elbow (Meattini et al, 2017) and hip (Seong et al, 2020) joints in load carrying/lifting tasks, for haptic rendering for finger-worn systems (Hosseini et al, 2018;Chossat et al, 2019) and virtual wall rendering with grounded haptic interfaces (Van and Harders, 2017;Feenstra et al, 2021). User studies by Hosseini et al (2018) and Chossat et al (2019) have demonstrated the capabilities of TSA to render haptic effects (haptic wall, stiffness) but the proposed interfaces were used to provide force feedback only to finger joints that require less powerful actuation.…”

“…This paper presents a preliminary design and characterisation of a wrist haptic device based on TSA. Compared to existing TSA-based haptic interfaces (Van and Harders, 2017;Hosseini et al, 2018;Chossat et al, 2019;Feenstra et al, 2021) the proposed device has been specifically developed for a human wrist support that requires significant torque generation capability. Robotic systems to assist human wrist flexion and extension require high actuation torques and control bandwidth.…”