Fabrication, enhancement, and comparative study of ferro-fluid-based haptic wearables

Abstract

The development of tactile devices is becoming very important, especially now that the virtual reality (VR) applications are becoming more common. The devices that have been designed respond to a wide variety of problems, a brief literature has been conducted about them. In this thesis, three different tactile devices, based on the ferrofluid tactile device, with different actuation principle were designed and fabricated. The objective is to conduct a comparison of capabilities (DoF, weight, bandwidth, speed, size, force exertion) and a user study to determine the capabilities of the three devices. The user study will be conducted with the help of ViESTac, a VR suite developed for evaluating different novel tactile devices with tasks that consider the properties of the tactile perception. The use of ViESTac allows to compare many devices under the same standard, thereby allowing the possibility to choose the right device for the right task. The thesis can be divided into four blocks. i. 3D modelling of the devices was carried out. They were printed using a 3D printer. The device was assembled, including solenoid winding, nitrile rubber, ferrofluid, neodymium magnets and other components. ii. Since different actuation mechanisms were used for the three different devices, therefore specific electronic circuits were designed for each of them, so that they could be actuated using the same power supply input. iii. The mechanical structure and electronics were designed in such a manner, so that all the devices would deliver similar orientation and texture feedback to the user. A proof-of-concept wearable prototype of the ferrofluid tactile device was also developed. iv. To check the feasibility of the devices and to have an objective and subjective comparison between them, this and this was done. The objective comparison considered the physical parameters of the devices, all put together in a table. The subjective involved a user study of 14 participants, conducted with ViESTac, a VR suite that was developed for testing tactile devices through different tasks. There are three different tasks (angle discrimination, texture discrimination and a pick and place task) each of them tested the capabilities of the devices and allowed to establish a comparison between them.