| dc.description.abstract | Impact in mechanical systems is an important concept that has been the focus of study for many years within mechanical engineering. It plays a critical role in various engineering domains such as engineering design, robotics, biomechanics, tribology, and machining. The collision of two objects results in the generation of significant contact forces between them, causing sudden changes in velocity, alterations in shape, vibration, and potential failure of the objects. Despite its significance in mechanical engineering, analyzing and predicting impact remains a complex and demanding task. Therefore, research in this area is highly important.
In robotics, collision with the environment or an object is often undesirable. The trajectory of robotic devices is carefully planned to avoid any collision. However, many multi-body dynamical systems undergo impact while performing their tasks, such as industrial manipulators walking robots, and space robots. Controlling the impact of a robotic manipulator is a difficult and frequent issue in situations where an automated system needs to interact with its environment. There are two main ways to deal with these issues. The first method is to add more redundancy to the robot's kinematics to reduce sudden force effects, while the second method involves developing multiple control strategies to manage various dynamic situations. The serial impact of a two-link planar robot with generalized active force controller is investigated.
The normal and oblique impact of an elastic sphere (tennis ball) on a granular surface (clay) and two different plastic tape lines is inverstigated. An experimental setup is built to precisely control drop height and impact angle. The ball's motion is recorded with a high-speed camera, and the action is analyzed using a dedicated MATLAB code. A theoretical viscoelastic impact model is proposed. The force coefficients of the theoretical model for impact on clay and impact on two tapes are determined using normal impact experiments and validated with oblique impact experiments. Obtained force coefficients for surfaces are compared. An ANOVA test is conducted to compare the statistical significance of the coefficient of restitution for surfaces.
Additive manufacturing technologies enable to manufacture of complex geometries in single or fever pieces, which requires assembly and high manufacturing costs with traditional manufacturing methods. Fused Filament Fabrication (FFF) and fused deposition modeling (FDM) also known as 3D printing, is an additive manufacturing process in which material is extruded layer by layer through a nozzle to create the desired shape of the printed object. Polylactic Acid (PLA) is a widely used polymer for 3D printing due to its low melting point, biodegradability, and lack of toxic fumes Additive manufacturing is widely used in industry, especially for prototyping. The impact dynamics of 3D-printed PLA in different infill densities are examined. A visco-elastic contact model is tuned using genetic algorithm. The force model results have good alignment with experiments and shows applicability of visco-elastic models for impact problems of 3D printed materials.
Next, an impact study involving animal locomotion is conducted. Lameness refers to an abnormality of horse gait usually caused by pain, discomfort, or mechanical restriction. Various factors such as trauma, birth defects, abnormalities acquired after birth, developmental issues, infection, metabolic problems, circulatory and nervous system disorders, or a combination of these can cause lameness. It leads to significant financial losses in the equine industry. Objective evaluation lameness requires special equipment and experts. The impact of the horse limb on the ground creates sound and incorporates critical information about the gait kinematic. With the help of technological advances in computation and artificial intelligence, we propose a convolutional neural network to diagnose lameness based on acoustic gaits. | en_US |
