Acoustics, Dynamics, and Controls Commons^™

Determination Of Acoustic Radiation Efficiency Via Particle Velocity Sensor With Applications, Steven Conner Campbell

Theses and Dissertations--Mechanical and Aerospace Engineering

Acoustic radiation efficiency is defined as the ratio of sound power radiated to the surface vibration power of a piston with equivalent surface area. It has been shown that the radiation efficiency is maximized and may exceed unity when the structural and acoustic wavelengths are approximately equal. The frequency at which this occurs is called the critical frequency and can be shifted with structural modifications. This has proven to be an effective way to reduce noise. The standard radiation efficiency measurement is comprised of an intensity scan for sound power measurement and accelerometer array for spatially averaged vibration determination. This …

The Effects Of System Characteristics, Reference Command, And Command-Following Objectives On Human-In-The-Loop Control Behavior, Seyyedalireza Seyyedmousavi

Theses and Dissertations--Mechanical and Aerospace Engineering

Humans learn to interact with many complex physical systems. For example, humans learn to fly aircraft, operate drones, and drive automobiles. We present results from human-in-the-loop (HITL) experiments, where human subjects interact with dynamic systems while performing command-following tasks multiple times over a one-week period. We use a new subsystem identification (SSID) algorithm to estimate the control strategies (feedforward, feedforward delay, feedback, and feedback delay) that human subjects use during their trials. We use experimental and SSID results to examine the effects of system characteristics (e.g., system zeros, relative degree, system order, phase lag, time delay), reference command, and command-following …

Procedure To Measure The Penetration Of One Mechanical Filter For Nanoparticles: Validation By Comparison, Pooya Abdolghader, Clothilde Brochot, Fariborz Haghighat, Ali Bahloul

Études primaires

Nanoparticles (NPs) are particles of less than or equal to 100 nm in diameter. Due to their size, they have a significant effect on health and safety of people. Capture of these NPs in general ventilation systems by filters remains one of the most widely used means of protection due to its relative simplicity of implementation and its effectiveness for capturing various size of particles. In North America, filters used in general ventilation systems are tested by the ANSI/ASHRAE Standard 52.2 and are graded according to their efficiency, which is a function of particle diameter. However, the current standard limits …

Optimal Power Flow Control Of Networked Dc Microgrids, Eddy H. Trinklein

Dissertations, Master's Theses and Master's Reports

The US military is moving toward the electrification of many weapon systems and platforms. Advanced weapon systems such as high energy radar, electro-magnetic kinetic weapons and directed energy pose significant integration challenges due to their pulsed power electrical load profile. Additionally, the weapons platforms, including ships, aircraft, and vehicles can be studied as a mobile microgrids with multiple generation sources, loads, and energy storage. There is also a desire to extend the mission profile and capabilities of these systems. Common goals are to increase fuel efficiency, maintaining system stability, and reduce energy storage size as typically required to enable pulsed …

Modeling Chevy Volt Gen Ii Supervisory Controller In Charge Sustaining Operation, Saurabh Bhasme

Dissertations, Master's Theses and Master's Reports

This report is focused on the development of Chevy Volt Gen II powertrain supervisory controller modeling for charge sustaining operation of the vehicle. The modeling process incorporated vehicle parameters and maps provided. The overall powertrain model along with the supervisory controller is developed in MAT- LAB/SIMULINK programming platform. The powertrain model includes all components which are the IC engine, two electric motors & associated TPIM, Battery, transmission auxiliary pump and spin-losses. The supervisory controller includes the vehicle drive mode selection model, the torque blending logic for charge sustaining along with friction brake modeling. The model has been developed to perform …

Automotive Driveline Backlash State And Size Estimator Design For Anti-Jerk Control, Kaushal Kumar Darokar

Dissertations, Master's Theses and Master's Reports

Vehicle drivability is an important factor which more and more customers have started assessing before buying a vehicle. Customers carry out this assessment based on both vehicle reviews/ratings and based on the test drives. One of common maneuver which a customers perform during the test drive is sudden accelerator pedal tip-in or tip-out to accelerate or coast the vehicle. Clunk and shuffle are the phenomena that usually occur during this scenario causing driver discomfort. The clunk and shuffle are caused by the backlash and compliance physical properties of the driveline. Consequently, control strategy needs to be developed which can provide …

A Hybrid-Powered Wireless System For Multiple Biopotential Monitoring, Shawn Li

Dissertations, Master's Theses and Master's Reports

Chronic diseases are the top cause of human death in the United States and worldwide. A huge amount of healthcare costs is spent on chronic diseases every year. The high medical cost on these chronic diseases facilitates the transformation from in-hospital to out-of-hospital healthcare. The out-of-hospital scenarios require comfortability and mobility along with quality healthcare. Wearable electronics for well-being management provide good solutions for out-of-hospital healthcare. Long-term health monitoring is a practical and effective way in healthcare to prevent and diagnose chronic diseases. Wearable devices for long-term biopotential monitoring are impressive trends for out-of-hospital health monitoring. The biopotential signals in …

Closed Loop Energy Maximizing Control Of A Wave Energy Converter Using An Estimated Linear Model That Approximates The Nonlinear Froude-Krylov Force, Yaqzan Mohd Yaqzan

Dissertations, Master's Theses and Master's Reports

Wave energy converters (WECs) exploit ocean wave energy and convert it into useful forms such as electricity. But for WECs to be successful on a large scale, two primary conditions need to be satisfied. The energy generated must satisfy the network requirements, and second, energy flow from waves to the grid needs to be maximized. In this dissertation, we address the second problem. Most control techniques for WECs today use the Cummins' linear model to simulate WEC hydrodynamics. However, it has been shown that under the application of a control force, where WEC motions are amplified, the linear model diverges …

Experimental Characterization Of Hydraulic System Sound, Ben Kolb

Dissertations, Master's Theses and Master's Reports

The purpose of this research was to establish test methods for characterizing the interaction between the hydraulic fluid and hydraulic hose at clipping points in mobile heavy equipment hydraulic systems. A simple hydraulic circuit test bench was developed and the laboratory axial piston pump was characterized using ISO 10767-1. A direct relationship between the fluidborne noise and structureborne noise present at each hose clip location was observed for a specific operating condition using operating deflection shapes and structureborne noise measurements. This result shows that optimal hose clip placement can be a viable solution to structureborne noise reduction. Additionally, a modal …

Using Frequency Based Substructuring To Optimize Multi-Axis Resonant Plate Shock Tests, Erica M. Jacobson

Dissertations, Master's Theses and Master's Reports

Resonant plate pyroshock tests only offer to test one component axis at a time, while the qualification pyroshock tests often have three single-axis specifications to meet. There is an interest in creating a multi-axis test environment from the single-axis resonant plate parts to save testing time, create a more realistic test environment, and monitor the possibility of an overtest. To investigate this, LaGrange-multiplier frequency based substructuring was implemented to virtually arrange the single-axis resonant plate subsystems into different assembly configurations and mathematically calculate the new assembly dynamics. A shock response spectrum was calculated from the new assembly dynamics through an …

Development Of A Fused Deposition 3d Printed Buoy And Method For Quantifying Wave Tank Reflections, Samantha G. Swartzmiller

Dissertations, Master's Theses and Master's Reports

Testing model scale prototypes is integral to the development of wave energy converter (WEC) technology. Model scale WECs are tested in wave tanks where they are subjected to repeatable wave fields. Their presence in water creates radiated waves that eventually reflect off tank walls disrupting the intended wave field. Fabrication of model scale WECs is another developing aspect of tank testing. Often model WECs are built of foam. Additive manufacturing is a promising alternative although the most common method, fused deposition modeling (FDM) 3D printing, does not typically produce waterproof parts. The goals of this work were 1) develop a …

A Biomimetic Approach To Controlling Restorative Robotics, Matthew T. Boots

Graduate Theses, Dissertations, and Problem Reports (ETD)

Movement is the only way a person can interact with the world around them. When trauma to the neuromuscular systems disrupts the control of movement, quality of life suffers. To restore limb functionality, active robotic interventions and/or rehabilitation are required. Unfortunately, the primary obstacle in a person’s recovery is the limited robustness of the human-machine interfaces. Current systems rely on control approaches that rely on the person to learn how the system works instead of the system being more intuitive and working with the person naturally. My research goal is to design intuitive control mechanisms based on biological processes termed …

Analysis And Control Of Fiber-Reinforced Elastomeric Enclosures (Frees), Soheil Habibian

Master’s Theses

While rigid robots are extensively used in various applications, they are limited in the tasks they can perform and can be unsafe in close human-robot interactions. Soft robots on the other hand surpass the capabilities of rigid robots in several ways, such as compatibility with the work environments, degrees of freedom, manufacturing costs, and safe interactions with the environment. This thesis studies the behavior of Fiber-Reinforced Elastomeric Enclosures (FREEs) as a particular type of soft pneumatic actuator that can be used in soft manipulators. A dynamic lumped-parameter model is created to simulate the motion of a single FREE under various …

Expendable 3d Printed Rescue Drone, Matthew Chapman, Nathan Knutty, Matthew Chapman

Williams Honors College, Honors Research Projects

This project team designed a 3D printed, expendable drone capable of flying for 80 minutes with a 5 lb payload in order to deliver rescue supplies to individuals in distress.

Theoretical Study Of Fano Resonance In A Mechanical System, Alex Alberts

Williams Honors College, Honors Research Projects

Resonance conditions are a major area of study in theoretical and experimental investigation. Normally, a resonance condition is characterized by a symmetric shape on either side of the resonance. In some cases, we can observe an asymmetric resonance shape, which is called a Fano resonance. We will study the appearance of Fano resonance in a purely mechanical system. The frequency response of the primary system is approximated using the method of multiple scales focusing on the location of the resonance condition. Then, curve fitting is used to approximate the Fano parameter associated with the system, which provides a measurement of …

Improved Low-Frequency Impact Insulation Class Measurements Based On Comparison Techniques, Sunit Girdhar

Dissertations, Master's Theses and Master's Reports

In today’s world, noise pollution is growing as a major concern and it is becoming more and more difficult to find quiet places. But when the problem escalates to the extent that people are annoyed with loud noises even in their apartments, it becomes an alarming issue for engineers. Around the world, cities have defined some basic performance requirements for buildings, and isolation of residents from noise is one of the cardinal performance requirements. In the United States, building codes use the Impact Insulation Class (IIC) rating to characterize the performance of floor/ceiling assemblies. This method uses the response measured …

Comparative Study And Design Of Economical Sound Intensity Probe, Karan Gundre

Dissertations, Master's Theses and Master's Reports

The theory of sound intensity measurement using the two-microphone method was first developed in the late 1970s. Even though the measurements were limited by the technology of the time, the theory was straight-forward and considerable attention was given to improving precision during testing or post-processing. With the development of modern equipment, however, the focus shifted to the apparatus. The commercial intensity probes available today have microphones that are already phase-matched. This eliminates the need for correction during or post-testing as a majority of the errors are minimized before any data is even collected. Although such intensity probes facilitate taking precise …

Acoustic Localization Techniques For Application In Near-Shore Arctic Environments, Miles B. Penhale

Dissertations, Master's Theses and Master's Reports

The Arctic environment has undergone significant change in recent years. Multi-year ice is no longer prevalent in the Arctic. Instead, Arctic ice melts during summer months and re-freezes each winter. First-year ice, in comparison to multi-year ice, is different in terms of its acoustic properties. Therefore, acoustic propagation models of the Arctic may no longer be valid. The open water in the Arctic for longer time periods during the year invites anthropogenic traffic such as civilian tourism, industrial shipping, natural resource exploration, and military exercises. It is important to understand sound propagation in the first-year ice environment, especially in near-shore …

Online Learning Of The Spatial-Temporal Channel Variation In Underwater Acoustic Communication Networks, Wensheng Sun

Dissertations, Master's Theses and Master's Reports

Influenced by environmental conditions, underwater acoustic (UWA) communication channels exhibit spatial and temporal variations, posing significant challenges for UWA networking and applications. This dissertation develops statistical signal processing approaches to model and predict variations of the channel and relevant environmental factors. Firstly, extensive field experiments are conducted in the Great Lakes region. Three types of the freshwater river/lake acoustic channels are characterized in the aspects of statistical channel variations and sound propagation loss, including stationary, mobile and under-ice acoustic channels. Statistical data analysis shows that relative to oceanic channels, freshwater river/lake channels have larger temporal coherence, higher correlation among densely …

Development Of Electromagnetic Friction Dampers For Improving Seismic Performance Of Civil Structures, Mohsen Amjadian

Dissertations and Theses

Energy dissipation is critical to limiting damage to civil structures subjected to extreme natural events such as earthquakes. Friction is one of the most reliable mechanisms of energy dissipation that has been utilized extensively in friction dampers to improve seismic performance of civil structures. Friction dampers are well-known for having a highly nonlinear hysteretic behavior caused by stick-slip motion at low velocities, a phenomenon that is inherent in friction and increases the acceleration response of the structure under control unfavorably, in spite of the fact that the displacement is generally reduced because of the energy dissipation. This increase in acceleration …

Immunity-Based Framework For Autonomous Flight In Gps-Challenged Environment, Mohanad Al Nuaimi

Graduate Theses, Dissertations, and Problem Reports (ETD)

In this research, the artificial immune system (AIS) paradigm is used for the development of a conceptual framework for autonomous flight when vehicle position and velocity are not available from direct sources such as the global navigation satellite systems or external landmarks and systems. The AIS is expected to provide corrections of velocity and position estimations that are only based on the outputs of onboard inertial measurement units (IMU). The AIS comprises sets of artificial memory cells that simulate the function of memory T- and B-cells in the biological immune system of vertebrates. The innate immune system uses information about …

A Transfer Matrix Model Of The Iec 60318-4 Ear Simulator: Application To The Simulation Of Earplug Insertion Loss, Yu Luan, Franck Sgard, Simon Benacchio, Hugues Nélisse, Olivier Doutres

Études primaires

The IEC 60318-4 ear simulator is used to measure the insertion loss (IL) of earplugs in the ear canal of an acoustical test fixture (ATF) and is designed to represent an average acoustic impedance (in a reference plane) of the human ear. The ear simulator is usually modeled using a lumped parameter model (LPM) which has frequency limitations and inadequately accounts for the thermo-viscous effects in the simulator. The simulator numerical models that can better deal with the thermo-viscous phenomena often lack essential geometric details. Most related studies also suffer from the lack of experimental validation of the models. Therefore, …

Design And Implementation Of An Instantaneous Fuel Mass Flow Measurement System For Use In Verification Of Locomotive Emissions, Adam Wayne James

Graduate Theses, Dissertations, and Problem Reports (ETD)

Located in Altoona, PA, the Juniata Thoroughbred Emissions Research lab has provided emissions testing and research for several locomotive companies such as CSX, Electro Motive Diesel (EMD), and General Electric (GE). The emissions laboratory measures locomotive emissions through partial flow dilution (PFD) sampling for particulate matter (PM) using a Sierra Instruments BG3 and measures raw gaseous emissions using a MEXA 7100D gaseous emission analyzer. Fuel consumption is measured on a gravimetric basis and is used in verification of proportional sampling of exhaust flow. There were two research goals for this study which were (1) verify that the emissions measurement system …

Mpc-Based Autonomous Driving Control With Localized Path Planning For Obstacle Avoidance And Navigating Signalized Intersections, Sai Rajeev Devaragudi

Dissertations, Master's Theses and Master's Reports

Connected and autonomous vehicles are becoming the major focus of research for the industry and academia in the automotive field. Many companies and research groups have demonstrated the advantages and the requirement of such technology to improve the energy efficiency of vehicles, decrease the number of crash and road accidents, and control emissions.

This research delves into improving the autonomy of self-driving vehicles by implementing localized path planning algorithms to introduce motion control for obstacle avoidance during uncertainties. Lateral path planning is implemented using the A* algorithm combined with piecewise Bezier curve generation which provides an optimum trajectory reference to …