Browsing by Author "Premarathna, CP"

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item: Conference-Abstract
Development of wearable fingertip tactile display driven by bowden cables
Premarathna, CP; Kulasekera, AL; Chathuranga, DS; Lalitharatne, TD
This paper presents the development and human interaction evaluation of a Bowden cable based wearable fingertip tactile display. This device is designed to be used in the field of virtual reality and teleoperation to render different types of tactile sensations such as grip force, slipping, roughness and softness through delivering normal force, skin stretch, tangential movement and vibration indication to the user. This paper evaluates the proposed device’s capability in delivering individual taxel actuation through user testing. A four taxel actuation system fixed to a mild steel skeleton is covered in silicone rubber to ensure wearer comfort. A secondary mechanism is developed to provide sliding and lateral skin stretch sensation to the user. In addition, an 8 mm diameter piezo vibration motor is used to deliver vibration to indicate slipping to the user. The force feedback system consist of four independently operable taxels positioned at 2mm center to center distance on the fingertip. Each taxel was actuated via a Bowden cable connected to a geared DC motor, mounted on a lower arm worn sleeve. A taxel discrimination experiment was done to validate human discrimination ability of each taxel and the results showed that a healthy human can distinguish each taxel with 87.45 % mean accuracy.
item: Conference-Full-text
Leveraging virtual reality for robot manipulator education
(IEEE, 2023-12-09) Yapa, A; Ratnayake, K; Premarathna, CP; Thayananthan, T; Abeysooriya, R; Adikariwattage, V; Hemachandra, K
Equipping students with hands-on experience and knowledge of robot manipulators is crucial as robotics becomes more applicable in Industry 4.0. However, the practical implementation of physical manipulators in educational settings is challenging due to high capital costs, operational expertise requirements, safety considerations, and remote accessibility. This paper introduces an approach to address these obstacles by implementing a Virtual Reality (VR) platform for studying robot manipulators. The paper details the conceptual methodology, containing five domains: 3D Modelling, Application of Mechanics, VR Development, VR Integration, and Application Development. The methodology shows the creation of three VR applications focusing on distinct learning scenarios. The first application offers an overview of manipulators, while the second illustrates a specific operation (pick-and-place), providing insights into the combined function of links and joints. The third application allows users to interact with the manipulator, facilitating the execution of programming tasks. The paper concludes by outlining the benefits and the features of a VR manipulator over a physical robot manipulator. Then, it outlines the future enhancements, including developing a digital twin for the VR manipulator and a series of laboratory experiments. The study illustrates a crucial step towards broadening the accessibility of robotics education.
item: Conference-Abstract
A Novel fabrication method for rapid prototyping of soft structures with embedded pneumatic channels
Premarathna, CP; Kulasekera, AL; Chathuranga, DS; Lalitharatne, TD
Soft robotics is a major disruptive technology that is rapidly revolutionizing the world of robotics. As the design optimization of these soft robotic structures are still in its infancy, their designers have to resort to prototype testing. This paper describes how a novel casting method based on a 2D layered approach and thermal programming of pneumatic tubing can be used to simplify soft structure prototyping. The proposed casting method is based on the sequential stacking of laser-cut pre-fabricated plates, i.e. PMMA (acrylic) sheets, to create a 3D mold, instead of the traditional methods of fabricating 3D molds, such as CNC machining or 3D printing. Contemporary soft robotic applications are more interested in pneumatic actuation and thus require pneumatic channels embedded within their structure. Creation of channels is a critical factor that limit the fabrication scope of most such soft structures. A simple solution is using Polyurethane (PU) tubing to create channels within soft structures. A limitation of PU tubes is that, they cannot be directly embedded as any twist added to obtain the required path of the tube adds a strain on the soft structure from within, which can affect the desired operation. Hence, the authors propose removing the strain on the PU tubes by thermally programming the required shape onto the PU tube. PU tubes reinforced with copper cores are bent in to the desired shape and are heat treated to program the desired shape. After placing the programmed tubes within the mold, silicon rubber can be simply poured into the mold; and the finished structure can be taken out of the mold once cured. Main purpose of this paper is to present these two novel fabrication methods to simplify soft robotic prototyping, without the need for advanced, costly, complex equipment.