A. James Clark School of Engineering
Permanent URI for this communityhttp://hdl.handle.net/1903/1654
The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
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Item Demonstrating Cognition by Task Execution and Motion Planning with different algorithms for Manipulation(2018) DIMITRIADIS, DIMITRIOS; Baras, John S.; Electrical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In this Thesis we demonstrate the whole path until the manipulation and the planning of the Baxter Robot. We start by analyzing the kinematic analysis of a six degrees of freedom robot. We build our analysis starting from the Denavit-Hartenberg method. We proceed with the kinematic equations of the robot and with the inverse kinematics as well as with a kinematic simulation of its movement with matlab. In order to reach our final goal we continue with the kinematic and dynamic analysis of the Baxter robot. We again state the Denavit-Hartenberg matrix, but this time we continue by building the dynamic model of the Baxter robot through the Euler-Lagrange equations. Moving on, we explore planning algorithms. The knowledge of which will help us in order to finally be able to formulate our path planner for the Baxter robot. We experiment ourselves by implementing four planning algorithms in different path planning problems. We construct the RRT and the RRT* algorithms in Python and we process them in different planning problems. Moving on, we also implement a planning problem in which Q-Learning and Sarsa algorithms are being used. We demonstrate how those two planning and learning algorithms work in our specified problem and we compare our results. Having knowledge on dynamic and kinematic robotic analysis and planning and motion planning algorithms we then experiment ourselves with the Baxter simulator on Gazebo. Also we plan the Baxter robot with Moveit!, getting familiar with the use of ROS as well as with the software. We add obstacles in our world and we plan our Baxter robot measuring its speed. We finally build a different plan algorithm RRT+ by focusing on searching for a secure and realizable path plan starting from the lower dimension space and then adding degrees of freedom to our Baxter robot. Concluding, we have built the desired steps for someone in order to build up the required knowledge to deal with robots and artificial intelligence planning.Item Development of Planning And Evaluation Models For Superstreets(2016) Xu, Liu; Chang, Gang-Len; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Despite the extensive implementation of Superstreets on congested arterials, reliable methodologies for such designs remain unavailable. The purpose of this research is to fill the information gap by offering reliable tools to assist traffic professionals in the design of Superstreets with and without signal control. The entire tool developed in this thesis consists of three models. The first model is used to determine the minimum U-turn offset length for an Un-signalized Superstreet, given the arterial headway distribution of the traffic flows and the distribution of critical gaps among drivers. The second model is designed to estimate the queue size and its variation on each critical link in a signalized Superstreet, based on the given signal plan and the range of observed volumes. Recognizing that the operational performance of a Superstreet cannot be achieved without an effective signal plan, the third model is developed to produce a signal optimization method that can generate progression offsets for heavy arterial flows moving into and out of such an intersection design.Item Efficient People Movement through Optimal Facility Configuration and Operation(2013) Feng, Lei; Miller-Hooks, Elise; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)There are a variety of circumstances in which large numbers of people gather and must disperse. These include, for example, carnivals, parades, and other situations involving entrance to or exit from complex buildings, sport stadiums, commercial malls, and other type of facilities. Under these situations, people move on foot, commonly, in groups. Other circumstances related to large crowds involve high volumes of people waiting at transportation stations, airports, and other types of high traffic generation points. In these cases, a myriad of people need to be transported by bus, train, or other vehicles. The phenomenon of moving in groups also arises in these vehicular traffic scenarios. For example, groups may travel together by carpooling or ridesharing as a cost-saving measure. The movement of significant numbers of people by automobile also occurs in emergency situations, such as transporting large numbers of carless and mobility-impaired persons from the impacted area to shelters during evacuation of an urban area. This dissertation addresses four optimization problems on the design of facilities and/or operations to support efficient movement of large numbers of people who travel in groups. A variety of modeling approaches, including bi-level and nonlinear programming are applied to formulate the identified problems. These formulations capture the complexity and diverse characteristics that arise from, for example, grouping behavior, interactions in decisions by the system and its users, inconvenience constraints for passengers, and interdependence of strategic and operational decisions. These models aim to provide: (1) estimates of how individuals and groups distribute themselves over the network in crowd situations; (2) an optimal configuration of the physical layout to support large crowd movement; (3) an efficient fleet resource management tool for ridesharing services; and (4) tools for effective regional disaster planning. A variety of solution algorithms, including a meta-heuristic scheme seeking a pure-strategy Nash equilibrium, a multi-start tabu search with sequential quadratic programming procedure, and constraint programming based column generation are developed to solve the formulated problems. All developed models and solution methodologies were employed on real-world or carefully created fictitious examples to demonstrate their effectiveness.Item Evaluation-Focused Reliability Test Program Planning Methodology(2013) Tamburello, Robert Nicholas; Herrmann, Jeffrey W; Mechanical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In practice, various ad hoc approaches for designing reliability test programs have been observed. Many of these approaches rely on previously established rules of thumb for which the underlying rationale is indefensible. As a consequence, those who use such approaches are unlikely to maintain a firm resource commitment for the conduct of reliability test program activities. Furthermore, it is difficult to ascertain the impact that budgetary cuts will have on the adequacy of the reliability test program with any degree of accuracy. The contributions of this research are as follows. This dissertation presents a novel 7-step planning process to aid practitioners in designing adequate reliability test programs. This planning process serves as a tool to systematically identify, quantify, and mitigate evaluation risks subject to resource constraints. By performing the 7 steps associated with this planning process, practitioners will be able to logically justify reliability test program requirements and more effectively articulate the significance of evaluation risks associated with a particular reliability test program design. Additionally, it is a straightforward process to assess the impact of a reduction in reliability test program resources. This planning process includes a step for assessing the level of risk associated with key aspects of the reliability test program. One such consideration that is of paramount importance is the adequacy of the test configuration of the system. Hence, we present a simulation-based approach for assessing the adequacy of the test configuration of a complex system-of-systems. For the purpose of demonstration, an application of this approach to air defense systems is included; however, the approach is valid for any type of system. As well, this dissertation presents an evaluation risk assessment process for reliability test programs--adapted from the traditional failure mode and effects analysis (FMEA) process. This process can be applied to any reliability test program, irrespective of the manner in which the plan was formulated. Just as a FMEA facilitates the identification of potential weaknesses in a system architecture, this evaluation risk assessment process is designed to surface reliability test program weaknesses and gauge the potential impact of each weakness to the system reliability evaluation.