Jovanova, Jovana

Preferred name

Jovanova, Jovana

Official Name

Jovanova, Jovana

Main Affiliation

jovana.jovanova@mf.edu.mk

Now showing 1 - 10 of 15

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ENERGY HARVESTING USING PIEZOELECTRIC CERAMICS INCORPORATED IN A SHOE-SOL
(University Ss. Cyril and Methodius in Skopje, 2020)
Grazhdani, Franka
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Anachkova, Maja
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Design framework for mechanically intelligent bio-inspired grasper
(Springer Science and Business Media LLC, 2025-05-20)
Changoski, Vasko
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Domazetovska Markovska, Simona
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The challenge of designing real-world robots continues due to the complexities of navigating inaccessible terrains and encountering unexpected conditions. Introducing smart materials like shape memory alloys (SMAs) in the robot body can be beneficial due to their shape memory effect for actuation; however, there is no systematic way to introduce SMAs in a robot design. This research aims to address these challenges by proposing a design framework for SMA-actuated smart structures in robotic applications. Drawing inspiration from nature, the initial step in this framework involves conceptualizing a multifunctional grasper. This grasper utilizes SMA springs actuated by electric current, enabling various movements such as crawling, grasping, and folding. Analytical modeling is employed to determine the necessary characteristics of the SMA springs for one segment of the grasper. A multi-body modeling approach is utilized for more comprehensive understanding of the robot performance. This approach verifies the results of the analytical modeling and allows for performance optimization. Grasper’s dynamics is enhanced by fine-tuning actuation input signals, resulting in a more precise, sustainable, and energy-efficient grasper that is capable of traveling 400% longer distance than the initial concept design. The conducted experiments confirm that the proposed design framework for mechanically intelligent grasper has the potential to streamline the SMA-actuated structure design process by reducing development time, minimizing the trial-and-error iterations, and yielding cost savings in both development and prototyping phases.
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Modular Origami Robot Inspired by a Scorpion Tail
(American Society of Mechanical Engineers, 2018-09-10)
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Anachkova, Maja
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Petrevski, Dimitar
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Grazhdani, Franka
<jats:p>Arthropod animals like scorpions with modular body parts can be an inspiration for a robot’s structure. The design presented here relays on inter-connected origami towers, but could also be easily disassembled. Each origami tower is fully autonomous and at the same time is part of the robot as a whole. The towers are positioned between two platforms that enable modularity. The scorpion’s tale shape is achieved by the varying platform diameter resulting in cone-like form. Each tower is actuated independently to enable multiple degrees of freedom. Maneuvering with separated units, assists in easier reparation as well as replacement. Detaching the towers into separate parts makes this structure develop more precise movements, since every unit will move autonomously. Therefore, having a higher number of separated movements combined leads to a smooth bionic movement. So, the overall hierarchy will be modular contributing to a greater curvature bending of the whole structure. Actuating and maneuvering the robot in the main concept is done by separated electro motors, built in the platform. The basic structure will be built from thick paper with plastic coatings. The thick paper itself is lightweight, but at the same time flexible. To protect the paper towers, double plastic foil is placed as an outer coating which acts as an origami cover. This transparent layer is elastic hence it can follow and support the individual units’ movements.</jats:p> <jats:p>This work is focused on understanding origami towers kinematics and different combinations of inter-connected towers to achieve multiple degrees of freedom. A conceptual model is developed, supported by CAD and mathematical models. At the end a prototype is presented.</jats:p>
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Modeling of the Interface of Functionally Graded Superelastic Zones in Compliant Deployable Structures
(American Society of Mechanical Engineers, 2018-09-10)
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Domazetovska, Simona
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Frecker, Mary
Functionally graded compliant mechanisms can be fabricated with additive manufacturing technology by engineering the microstructural and compositional gradients at selected locations resulting in compositionally graded zones of higher and lower flexibility. The local compliance depends on the geometry of the structure as well as the material property in the selected region. As Nitinol (NiTi) is well suited for applications requiring compliance, the critical transformation stress and the superelastic modulus of elasticity are crucial parameters for defining the local compliance. To understand the behavior at the interface between two different material compositions, three models of gradient change between the alloys are analyzed: step change, linear and polynomial gradients. In addition to localize the deformation in the interface, three different flexure designs in the interface are analyzed. This paper will address a methodology for modeling and parametrization of material properties and transition at the interface, for different flexure designs. The combined effort in the interface of the functional grading and the geometry will be used for the design of monolithic self-deployable structures, initially folded in compact shape. The design motivation comes from the self-deploying mechanisms inspired by insects’ wings.
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Generative design of a large-scale nonhomogeneous structures
(Elsevier BV, 2021)
Djokikj, Jelena
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Modeling and Prototyping of Self-Folding Origami Structure
(American Society of Mechanical Engineers, 2019-09-09)
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Domazetovska, Simona
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Changoski, Vasko
Inspired by the spring blossoms of tulips and origami engineering, we have designed a monolithic self-deployable structure with the ability to fold (close) and unfold (open). The focus of this paper is the 3D design and prototyping of a self-folding origami structure actuated by shape memory alloys (SMAs). SMA actuators, spring and wires, provide controllable actuation based on the simplicity of their design and the shape memory effect. In mechanical engineering, the art of origami provides a novel approach for compliant mechanisms devices enabling relative movement between the components with reduction of the number of parts. The self-folding origami structures can be used in many applications for volume reduction in packaging and space engineering. Additive manufacturing technologies enable easy and fast prototyping of the monolithic structure. The geometry of the structure and the integration of smart active materials within the structure enable the design to achieve complete self-folding.
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Virtual Reality Supported Design of Smart Grasper
(American Society of Mechanical Engineers, 2021-09-14)
Djokikj, Jelena
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<jats:title>Abstract</jats:title> <jats:p>Smart material graspers have shown potential for different applications in terms of functionality and actuation, especially in handling arbitrary shapes, fragile objects and complex 3D geometries. However, to take these initial designs further towards real applications, the challenge remains to determine the optimal size, shape, and passive and smart material location. Virtual reality can be beneficial in the early concept generation as it can help visualize and understand the grasping process. The access to suitable hardware and the development of virtual reality (VR) software has resulted in increased use of this technology. The 3D visualization offered by VR especially in the early stages of the design process assists engineers in making appropriate and efficient decisions, and it can also support the interaction with the end user to iterate on potential design improvements.</jats:p> <jats:p>The conceptual phase is often overlooked and rushed by the other departments involved in the design and development process although it is of great importance for successful outcome. It is important to make the most of it in order to assure quality result. In order to ensure short conceptual phase that will not reflect on the products’ quality we propose introduction of the VR in the early stages of the design process.</jats:p> <jats:p>In this paper we show how the use of VR can be beneficial in new product development. In this case we focus on the design of smart material grasper.</jats:p>
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Autonomous Multifunctional Vehicle With Integrated Bio-Inspired SMA Actuated Grasper
(American Society of Mechanical Engineers, 2020-09-15)
Changoski, Vasko
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Domazetovska, Simona
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Anachkova, Maja
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<jats:title>Abstract</jats:title> <jats:p>The space exploration activities are merging new technologies in order to develop systems challenged to achieve capabilities for high mission experience. Inspired by the numerous applications in space exploration, with the integration of shape memory alloys (SMAs), a 3D printed continuous All Terrain Grasper Transport (AT-GT) vehicle with implemented multi-locomotion grasper was created.</jats:p> <jats:p>In order to reduce failure of the mechanical system, the vehicle is equipped with SMA suspension and SMA tensioner of a pulley system with adaptable height able to achieve movement on a given trajectory and adjust to any terrain. SMA actuators provide controllable actuation based on the simplicity of their design and the shape memory effect.</jats:p> <jats:p>By using the advantages of the origami engineering, soft robotics and smart material implementation, a bio-inspired autonomous grasper was integrated on the AT-GT, capable of leaving the vehicle, grabbing an object and bringing it back to the vehicle.</jats:p> <jats:p>The concept development, the analytical models and the prototype including the benefits of the combined work of the vehicle and the grasper are presented.</jats:p>
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Enchanced Functionality Design of Soft Grabbing Robot With Virtual Reality
(American Society of Mechanical Engineers, 2022-09-12)
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Djokikj, Jelena
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<jats:title>Abstract</jats:title> <jats:p>The design phase in robotics engineering is the core action for defining functionality. In soft robotics, especially in soft grabbing mechanisms, the challenge is to envision the interaction with different objects in terms of shape, size and stiffness. By enhancing the design phase with virtual reality (VR), all involved entities in the process are provided with a visualization method that facilitates the process and supports the functionality definition. In this way, utilizing VR, we exploit the possibilities of the designed soft grabbing robot and at the same time analyze different applications. When it comes to grabbing objects, application can vary over industry and sizes: from harvesting fruits and vegetables in the agricultural industry, over sorting objects in warehouses, to handling break bulk in ports. In this paper we demonstrate the use of VR in the conceptual design phase of a smart robotic grasper inspired by elephant’s trunk. By applying VR in the early stages of the design process, we can analyze the robot and its interaction with the environment and intervene if needed in the CAD model. With this approach we are saving resources but more importantly time and at the end of the design stage we are confident in the robot’s functionality and performances.</jats:p>
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Environmentally Friendly Bio-Inspired Turtle Robot
(American Society of Mechanical Engineers, 2020-09-15)
Domazetovska, Simona
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Ivanoski, Kristijan
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Josifovska, Stefani
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Slavkovski, Viktor
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<jats:title>Abstract</jats:title> <jats:p>Inspired by the movement of a turtle in nature, a low-budget turtle-like robot was designed and developed to operate on natural terrain. Applying affordable additive manufacturing (3D printing) leads into creating unique 3-D structure with potential of flexibility, multi-functionality and multi-movement. By implementing solar panels, the energy from the sun is used, which makes the robot self-sustainable. The robot is controlled remotely with an android application designed for the need of this work.</jats:p> <jats:p>The bio-inspired robot can play an interesting role in real-life applications, such as monitoring in hardly accessible terrain, video and data collection for environmental friendly application, animals’ observation and others. The main application of the robot is for animal observation in the zoo, so it will often need to move across not even landscape in order to allow surveillance of that area. By implementing smart materials, the movement of the turtle can be improved.</jats:p> <jats:p>This paper presents the design concepts and functionality, together with CAD model of the robot, the prototyping (hardware, control and application design) and the results from the measurements.</jats:p>

Jovanova, Jovana

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