1,721,105 research outputs found
Optimal design and modelling of complaint micro-linkage mechanism
No full textIn this project we investigate the feasibility of using the pseudo-rigid-body modelling technique in examining a simple modular compliant mechanism. An optimum design is tested through a modelling technique built around the concept of the pseudo-right-body. A mathematical model is constructed to determine the non-linear behavior of large-deflections. The problem is solved using an iterative method as it cannot be simplified to a closed loop equation. The solution to the non-linear model is then compared to empirical results collected from a mock up of the compliant device. The pseudo-rigid-body model is then combined with a linear model to develop the complete solution, which is determined to be fairly close to the actual behavior of the mock up. The dynamic analysis is then conducted on the same model, where the solution from the model is used alongside numerical methods in the MATLAB environment. Finally, possible applications of this device are briefly discussed
Investigation of a novel type of locomotion for a snake robot suited for narrow spaces
Get PDFIn snake robot research, one of the most efficient forms of locomotion is the lateral undulation.
However, lateral undulation, also known as serpentine locomotion, is ill-suited for narrow spaces, as
the body of the snake must assume a certain amount of curvature to propel forward. Other types of
motion such as the concertina or rectilinear may be suitable for narrow spaces, but is highly inefficient
if the same type of locomotion is used even in open spaces. Though snakes naturally can interchange
between the use of serpentine and concertina movement depending on the environment, snake robots
based on lateral undulation to date are unable to function satisfactorily in narrow spaces. In
undergoing concertina movement, the snake lifts part of its body off the ground to reduce friction; this
cannot be reproduced in planar snake robots. To overcome the inability to adapt to narrow spaces, a
novel type of a gait is introduced. With slight modifications to the members of the multi-link snake
robot, the robot normally developed for lateral undulation is able to utilize the new gait to negotiate
narrow spaces. The modifications include alterations to the snake segments as well elements that
mimic scales on the underside of the snake body. Scales, often overlooked in locomotion research,
play an important role in snake movement by increasing backward and lateral friction while
minimizing it in forward direction. This concept provides the basis for movement in the proposed gait.
Through kinematic studies the viability of this gait is illustrated
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Repurposing a sampling-based planner for a six-degree-of-freedom manipulator to avoid unpredictable obstacles
Get PDFThis paper presents the use of a sampling-based planner as a reactive planning scheme to avoid obstacles between a robotic arm and a moving obstacle. Based on a planner benchmark on an obstacle-ridden environment, a rapidly-exploring random tree (RRT) planner has been used to populate the trajectories of the task space and map them into a configuration space using a Newton-Raphson-based inverse kinematic solver. Two robot poses are defined in a cycle of back-and-forth motion; the initial and the goal poses. The robot repeatedly moves from the starting pose to the end pose via the midpoint pose. Each set of trajectories is unique. We define this unique solution within the context of the configuration space as a cycle space. We impose a periodically occurring synthetic obstacle that moves in and out of the robot arm workspace defined in a simulated environment. Within the robot's workspace, the obstacle moves and cuts through the cycle space to emulate a dynamic environment. We also ran a benchmark on the available sampling planner in the OMPL library for static obstacle avoidance. Our benchmark shows that the RRT has the lowest time planning time at 0.031 s compared with other sampling-based planners available in the OMPL library, RRT implicitly avoids singularities within the cycle space, and reactively attempts to avoid synthetic moving objects near the robot hardware. This research intends to further investigate on the use of RGB-D sensor and LiDAR to track moving obstacles while abiding by the task space commands described by the initial and goal poses
AI-based detection of potholes ahead of a visually impaired person using ultrasonic sensors array and camera for blind navigation
Get PDFVisually impaired individuals usually depend on
assistive devices like white canes, frequently equipped with
ultrasonic sensors, for navigation. However, these devices face
significant limitations, particularly in detecting specific hazards
such as potholes and deep trenches on walkways. This gap in
functionality increases the risk of accidents and impedes safe,
independent navigation for the visually impaired. The research
developed a prototype of a blind assistive system equipped with
an array of ultrasonic sensors and a Raspberry Pi integrated
with Firebase for IoT capabilities. AI models, trained on the
collected datasets of road images and ultrasonic sensor readings,
were deployed on the Raspberry Pi. Testing in real-world
scenarios was conducted to validate the prototype's
effectiveness. The results showed that the AI model successfully
detected potholes with an accuracy of 93%. The prototype could
detect both large and small potholes using ultrasonic sensors
and a camera but faced challenges in cases where potholes were
filled with water or in complex environments
Hexapod robot for autonomous machining
No full textProduct miniaturization is a key aspect of manufacturing nowadays. Computer numerically controlled (CNC) machine tools are the major tools used in manufacturing industries for producing miniaturized products. However, CNC machines are still big, bulky and stationary. This research is an effort to develop a modular machine on a robotic platform which would be able to carry out machining operation. Hexapod robots are mobile, small and stable robots which are developed having a lot of variety. In this project a Hexapod robot was designed and fabricated for machining operation. The research scope for this project was limited to 1-D machining i.e. drilling operation. A suitable existing robot (hexapod) design was followed in this project. A drilling spindle was attached with the robot to carry out the machining operation. The robot was controlled using serial communication. A GUI (Graphical User Interface) was developed to control the Hexapod which had all the required algorithm inside. Machining operations were carried out with the prototype robot to test its performance. The highest accuracy was found using spindle speed of 2500RPM and velocity of 200mm/min. The repeatability found using these parameters were around 25micron. The positional accuracy of the robot movement was compared with that of an existing commercial micromachining system. The performance of the robot was found to be almost similar to that of the commercial machine
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