Acoustics, Dynamics, and Controls Commons^™

Treadmill Platform For Quadrupedal Robots, Baxter J. Bartlett, Jack F. Butler, Phillip A. Shafik, Tarun S. Ganamur

Mechanical Engineering

Cal Poly Legged Robots, led by Professor Refvem and Professor Xing, has been leading Cal Poly’s attempts to simulate, produce, and test their legged robots. The initial testing of the locomotion of these robots can be dangerous to the robot since any bugs in the code could cause the robot to fall over and harm itself. Our responsibility as a team was to deliver a portable platform for testing the locomotion capabilities containing a fall prevention mechanism. In short, we have designed a platform for this purpose that consists of a treadmill surrounded by a wheeled chassis with a system …

Damage Identification In 3d Printed Metal Parts Using Deep Learning, Romaine Byfield, Alireza Modir, Ibrahim Tansel, Raniero Plaza

Florida Conference on Recent Advances in Robotics

An active Structural Health Monitoring (SHM) method called Surface Response to Excitation (SuRE), is used in this study to detect and quantify the damages created by a milling operation on additively manufactured metal plates. This method entails bonding two piezoelectric disks to the test specimens, one to excite it with surface waves from one end of the plate, and the other to sense the dynamic response to excitation at the other end. A sweep sine wave with a duration of 1 ms, ranging from 50-120 kHz is used as the excitation signal. Five stainless steel plates of identical size (195×54×2.5 …

Comparing Probabilistic Planning Success On Three Types Of Robots: Wheeled, Legged, And Underwater, Daniel Griessler, Josias Moukpe, Braidan Duffy, Akil Hosang, Blake Janes, Omar Jebari, Kourtnee Fernalld, Erbene De Castro, Humberto Rivera, William Stern, Badria Alfurhood, Akram Alghanmi, Marius Silaghi

Florida Conference on Recent Advances in Robotics

We compare the relevance of POMDP graphical models to addressing a given common task, the autonomous navigation, in mobile robotics, for robots in three different environments: legged walking, wheeled, and underwater robots. Principled approaches to the implementation of Intelligent robots in realistic environments with uncertainty exploit probabilistic models. The use of graphical models increases tractability and verifiability of probabilistic reasoning. Our robots face similar localization problems of passing by three doors on a corridor in a building, respectively, for the underwater case, of passing by three barrels in a pool. All the three robots are equipped solely with noisy sonars …

Electromagnetically Actuated Modular Robots With Controlled Self-Assembly And On-Demand Disassembly, Anuruddha Bhattacharjee

Mechanical Engineering Research Theses and Dissertations

Modular reconfigurable robots, with on-demand assembly and disassembly, offer the possibility of mesoscale (milli- and microscale) manufacturing. However, most of the existing modular robotic platforms currently being designed and functionalized rely on complex actuation and assembly mechanisms and so lack further scalability and transformability required for mesoscale applications. Therefore, this dissertation seeks to develop a novel scalable modular robotic platform with controlled self-assembly, disassembly, and reconfiguration techniques using an external electromagnetic field. While current cutting-edge research in this area uses a single magnet to move one module at a time into the target position, this dissertation explores processes to move …

Photonic Sensors Based On Integrated Ring Resonators, Jaime Da Silva

Mechanical Engineering Research Theses and Dissertations

This thesis investigates the application of integrated ring resonators to different sensing applications. The sensors proposed here rely on the principle of optical whispering gallery mode (WGM) resonance shifts of the resonators. Three distinct sensing applications are investigated to demonstrate the concept: a photonic seismometer, an evanescent field sensor, and a zero-drift Doppler velocimeter. These concepts can be helpful in developing lightweight, compact, and highly sensitive sensors. Successful implementation of these sensors could potentially address sensing requirements for both space and Earth-bound applications. The feasibility of this class of sensors is assessed for seismic, proximity, and vibrational measurements.

Covenant Persuasion Lead To Constitutionalism – Neither Was Invented, Joseph Livni

Helm's School of Government Conference - 2021-2024

Constitutionalism is a conviction shared by people that a government must act in compliance with a dominant charter. So is covenantal persuasion. The covenant reflects statutes and traditions etched in a living covenantal practice. The practice cannot exist without the persuasion and the persuasion cannot exist without the practice. Elazar was one of the most prolific scholars of the covenantal model. There is one point were the paper diverges from Elazar. The paper discusses a mathematical model and other studies of the covenant practice demonstrating that such a practice involves a multitude of simultaneous vital conditions. That led to the …

A Proof Of Concept For Detection Of Palato-Lingual Contact Without Intraoral Electrodes In A Human Participant, Amitava Biswas

Master's Theses

The author of this thesis conceived and investigated an unexpected electrical signal that may not be noticed during regular electroglottography (EGG) when electrodes are conventionally placed on the anterior surface of the throat. It appears that there is a measurable electrical signal from the EGG equipment when electrodes are placed over the frontal cheek (belly of zygomatic muscle), and the tongue is elevated to contact the hard palate, or the tongue is lowered to break the contact. Therefore, this phenomenon is designated as unconventional electroglottography (UEGG, Dr. Steven Cloud, private communication, July 17, 2022).

Two distinctive patterns of waveforms were …

Design And Data-Driven Identification Of A Quadruped Robot, Dakota Rufino

All Theses

The existence of nonlinearities and the lack of sufficient equations are fundamental challenges in modeling, analyzing, and controlling complex systems. However, recent developments revolutionizing the study of dynamical systems. An emerging method in nonlinear dynamical systems is the Koopman operator theory, which provides us with key advantages in performing the modeling, prediction, and control of nonlinear systems. The linear system representation allows us to leverage linear stability analysis. The first section of this thesis briefly covers the construction of a quadrupedal robot, a sufficiently complex nonlinear dynamical system, for the use of analyzing data-driven modeling techniques. The second section details …

Laser Stabilization Through Optical Turbulence, Liam Vanderschaaf

All Theses

Laser jitter presents a significant issue in the fields of laser communication and sensing. There are two main categories of positional noise in regards to the instantaneous centroid of a laser propagating over long distances: jitter resulting from optical turbulence and jitter resulting from mechanical vibrations. Optical turbulence was generated using Clemson University’s Variable Turbulence Generator (VTG). The VTG is capable of creating a desired level of optical turbulence that is comparable to atmospheric conditions with fried parameters greater than 0.3 cm. A gaussian laser was transmitted through the VTG and a system of Fast Steering Mirrors and Position Sensing …

Engineered Material Systems For Mimicking Tissue And Disease, Margrethe Ruding

McKelvey School of Engineering Graduate Student Theses & Dissertations

This thesis comprises two studies involving design and application of soft material systems. The goal of the first study was to design, fabricate, and characterize hydrogel lattice structures with consistent, controllable, anisotropic mechanical properties. Lattices, based on four types of unit cells (cubic, diamond, vintile, and Weaire-Phelan), were printed using stereolithography (SLA) of polyethylene glycol diacrylate (PEGDA). In order to create structural anisotropy in the lattices, unit cell design files were scaled in one direction by a factor of two in each layer and then printed. The mechanical properties of the scaled lattices were measured in shear and compression and …

Modeling, Simulation And Control Of Microrobots For The Microfactory., Zhong Yang

Electronic Theses and Dissertations

Future assembly technologies will involve higher levels of automation in order to satisfy increased microscale or nanoscale precision requirements. Traditionally, assembly using a top-down robotic approach has been well-studied and applied to the microelectronics and MEMS industries, but less so in nanotechnology. With the boom of nanotechnology since the 1990s, newly designed products with new materials, coatings, and nanoparticles are gradually entering everyone’s lives, while the industry has grown into a billion-dollar volume worldwide. Traditionally, nanotechnology products are assembled using bottom-up methods, such as self-assembly, rather than top-down robotic assembly. This is due to considerations of volume handling of large …

Experimental And Theoretical Analysis Of Nonlinear Triboelectric Energy Harvester For Frequency Up-Conversion Applications, Hadeel A. Abumarar

Mechanical Engineering Theses

With the development of micro-sensors and wireless applications, energy harvesting has become an effective method for self-powering. However, ambient energy is only limited to below 100Hz, which restricts the energy harvester designs to this range resulting in
an impractical bulky and large-scale harvester. Therefore, in this thesis, we investigated
frequency Up and Down conversion energy harvesters to benefit from the high-frequency oscillations and transferred them to the ambient vibration ranges. Toward this, the triboelectric transduction mechanism has been utilized for a frequency-up conversion for energy harvesting applications, while the piezoelectric transduction mechanism is used for frequency-down
conversion for mass sensing …

Motion Control Simulation Of A Hexapod Robot, Weishu Zhan

Dartmouth College Master’s Theses

This thesis addresses hexapod robot motion control. Insect morphology and locomotion patterns inform the design of a robotic model, and motion control is achieved via trajectory planning and bio-inspired principles. Additionally, deep learning and multi-agent reinforcement learning are employed to train the robot motion control strategy with leg coordination achieves using a multi-agent deep reinforcement learning framework. The thesis makes the following contributions:

First, research on legged robots is synthesized, with a focus on hexapod robot motion control. Insect anatomy analysis informs the hexagonal robot body and three-joint single robotic leg design, which is assembled using SolidWorks. Different gaits are …

Development Of Mirror Flexures For Use In The Muvi Instrument, Colin W. Harrop

Master's Theses

The Miniaturized Ultraviolet Imager (MUVI), is a compact wide field UV imaging instrument in development at UC Berkeley Space Sciences Laboratory and Cal Poly, San Luis Obispo. MUVI is designed to fit in a 2U CubeSat form factor and provide wide field, high resolution images of the ionosphere at far ultraviolet wavelengths. This thesis details the design and analyses of MUVI’s deployable cover mirror mounting flexures. Three different flexure geometries were evaluated, an optimal candidate was determined based on a number of criteria including isolation of vibration and stress to the mirrors, manufacturability and cost. The design of the flexure …

Cable Decoupling And Cable-Based Stiffening Of Continuum Robots, Parsa Molaei

LSU Master's Theses

Cable-driven continuum robots, which are robots with a continuously flexible backbone and no identifiable joints that are actuated by cables, have shown great potential for many applications in unstructured, uncertain environments. However, the standard design for a cable-driven continuum robot segment, which bends a continuous backbone along a circular arc, has many compliant modes of deformation which are uncontrolled, and which may result in buckling or other undesirable behaviors if not ameliorated. In this study, a detailed approach for using additional cables to selectively stiffen planar cable-driven robots without substantial coupling to the actuating cables is investigated. A mechanics-based model …

Trajectory-Tracking Control Of The Ball-And-Plate System, Dominic E. Riccoboni

Master's Theses

The Mechatronics group in the Mechanical Engineering department of Cal Poly is interested in creating a demonstration of a ball-and-plate trajectory tracking controller on hardware. The display piece will serve to inspire engineering students to pursue Mechatronics and control theory as an area of study. The ball-and-plate system is open-loop unstable, underactuated, and has complicated, nonlinear equations of motion. These features present substantial challenges for control - especially if the objective is trajectory tracking. Because the system is underactuated, common nonlinear trajectory tracking control techniques are ineffective. This thesis lays out a theoretical foundation for controlling the hardware.

Several important …

Estimation Of The Response, Power Spectra, And Whirling Patterns Generated From Mud Circulating Along The Annulus During Drilling Procedures: An Alternative Mathematical Representation Via Finite Element Modelling, Eleazar Marquez

Mechanical Engineering Faculty Publications

In this study, an alternative mathematical representation of a drill-string is proposed to provide an alternative assessment on BHA dynamic alterations. Lateral vibrations remain the focal point of drill-string breakdowns given their high frequency characterization and ability to deviate perforation trajectories from the subsurface target. In this paper, the proposed model consists of an anisotropic rotor subjected to distinct RPMs, an axial force, and a bidirectional harmonic excitation with specified amplitude and assorted duration to simulate annulus motion generated from the mud fluid. In this regard, Euler-Bernoulli beam theory was adopted to establish a complete MDOF mathematical expression and thus …

Development Of An Improved Mathematical Representation Which Captures The Nonlinear Dynamic Behavior Of A Drill-String Assembly, Eleazar Marquez

Mechanical Engineering Faculty Publications

In this study, an improved mathematical representation of a drill-string assembly is developed to provide an alternative assessment on vibration irregularities proliferating downhole due to bit-rock interference. Lateral vibrations receive particular attention due to their high frequency content which alter the dynamic response of the drill-string, instigate casing damage, and impede optimal penetration rates. The response of the drill-string is captured by synthesizing compatible stationary bit excitations, via an auto-regressive digital filter, and implementing Monte Carlo simulation, while the power spectral density function is approximated to elucidate the dynamic characteristics during drilling. Formulating adequate physical parameters for the equation of …

A Probabilistic Analysis In Vibration-Assisted Drilling To Measure Dynamic Behavior During Drilling And Understand Risk Factors, Eleazar Marquez, Samuel Garcia

Mechanical Engineering Faculty Publications

In this paper, a mathematical representation is proposed to further understand the dynamic behavior and risk factors associated with vibration-assisted drilling (VAD) technology. The proposed Timoshenko beam model, which characterizes VAD technology, consists of two passive, counter-rotating coaxial rotors operating simultaneously, subjected to a stochastic excitation. In this regard, a finite element technique was incorporated to determine the physical parameters of the governing equation of motion, where the shear and rotary effects, as well as the gyroscopic couples generated perpendicular to the axis of rotation, were accounted for. Further, the relative velocity between the coaxial rotors was accounted in the …

Gamelan Gong Directivity Dataset, Samuel D. Bellows, Dallin T. Harwood, Kent L. Gee, Micah R. Shepherd

Directivity

No abstract provided.

Effectiveness Of Acoustic Design In Public Spaces, Jana V. Jirgens

Honors Undergraduate Theses

In this thesis, a discussion on the effectiveness of acoustic design in public spaces is made. The auditory properties of a location have noteworthy implications on the success of a building's design and how a room is perceived. Depending on the requirements of each location, either a reverberant or sound-absorbing approach is best suited for the environment. Moreover, public health is negatively affected by long-term involuntary noise exposure. Because of this, there is an obvious demand for continued and expanded study in acoustic design. This thesis aims to challenge interior design choices made in four testing locations: a classroom, a …

Mechanical Energy Harvester For Powering Rfid Systems Components: Modeling, Analysis, Optimization And Design, Alireza Babaei

Theses and Dissertations--Mechanical and Aerospace Engineering

Finding alternative power sources has been an important topic of study worldwide. It is vital to find substitutes for finite fossil fuels. Such substitutes may be termed renewable energy sources and infinite supplies. Such limitless sources are derived from ambient energy like wind energy, solar energy, sea waves energy; on the other hand, smart cities megaprojects have been receiving enormous amounts of funding to transition our lives into smart lives. Smart cities heavily rely on smart devices and electronics, which utilize small amounts of energy to run. Using batteries as the power source for such smart devices imposes environmental and …

Experimental Uncertainty In Measurements Of Violin Impulse Response, Andrew Piacsek, Seth Lowery

All Faculty Scholarship for the College of the Sciences

Experiments that investigate how an individual musical instrument changes in response to subtle alterations must contend with measurement uncertainty, which typically arises from inconsistencies in the measurement setup. We quantify uncertainty in violin response measurements by measuring bridge admittance and radiatively of a single instrument that is repeatedly removed and reinstalled in our measurement apparatus. From this set of baseline measurements, we calculate the average and standard deviation of admittance and radiativity. The amount of variation observed in the baseline data is compared to the change in bridge admittance that occurred over several days due to a large and abrupt …

An Active Voice Coil Negative Stiffness Vibration Isolator With Application To Mobile 3d Printing, Lucas M. Schloemp

Dissertations, Master's Theses and Master's Reports

Equipment whose performance degrades when exposed to base vibration is often deployed in vibration-rich environments. Using 3D printers in mobile applications, such as vehicles and ships, are typical examples where the extruder and bedplate are easily excited by base vibration. A versatile active vibration isolator is considered in this thesis constructed using a voice coil actuator and a laser displacement feedback sensor to achieve a wide range of dynamic response characteristics, including negative stiffness. This approach permits transmissibility shaping to meet band-limited base isolation requirements without active damping vibration control. A combination of simulation and hardware validation is used to …

Programming The Bistable Dynamic Vibration Absorbers Of A 1d-Metastructure For Adaptive Broadband Vibration Absorption, Shantanu H. Chavan

Dissertations, Master's Theses and Master's Reports

This research addresses a critical challenge in structural engineering—achieving comprehensive vibration control and energy dissipation in meta-structures. Departing from the limitations of passive structures with fixed bandgaps, we propose an innovative approach utilizing active meta-structures capable of dynamically tuning their bandgaps. The primary goal is to introduce an efficient method for programming meta-structures with multiple variable bandgaps, thereby enabling effective vibration attenuation across a broad frequency spectrum.

The methodology involves transforming passive resonators into bistable adaptable Dynamic Vibration Regulators (DVRs) through a sophisticated switching mechanism. This adaptation sets the stage for numerous unique combinations by independently switching each resonator. A …

Study Of Eco-Driving And Charging Planning In Connected And Automated Vehicles Environment, Pradeep Bhat

Dissertations, Master's Theses and Master's Reports

In this dissertation, the development of eco-driving and charging planning algorithms in the connected and automated vehicle environment (CAV) are presented. CAV technologies provide opportunities for potential energy savings and efficiency improvement of transportation networks, which are explored through multiple research tasks in this study.

The objective of the first study presented in Chapter 2 is to reduce vehicle dynamic losses and required tractive force while completing trip distance within a given travel time. Sequential Quadratic Programming method is employed for this nonlinearly constrained optimization problem. The validation result illustrates the benefits of optimal velocity trajectories. The objective of the …

Correlation Of And Development Of Procedure To Use A Resonant Plate With Mechanical Excitation For Shock Testing Small-To-Medium Size Spacecraft And Provide Aerospace Shock Analysis And Testing Guidelines, Monty Kennedy

Dissertations, Master's Theses and Master's Reports

In the aerospace industry it is known that performing shock analysis and testing on spacecraft is difficult to do mostly because shock loads create a very short duration shock wave transient that can have high acceleration peak levels (1,000-5,000 g) and wide frequency content (100-10,000 Hz). FE (finite-element) shock analysis is difficult because implicit linear FE software commonly used for most vibration analysis in aerospace does not account for shock wave propagation, reflection, and attenuation that occurs based upon the distance from the shock source at the base of the spacecraft and the attenuations that occurs through mechanical joints. Spacecraft …

Jet Noise Reduction: A Fresh Start, Christopher K. Tam, Fang Q. Hu

Mathematics & Statistics Faculty Publications

Attempts to reduce jet noise began some 70 years ago. In the literature, there have been many publications written on this topic. By now, it is common knowledge that jet noise consists of a number of components. They possess different spectral and radiation characteristics and are generated by different mechanisms. It appears then that one may aim at the suppression of the noise of a single component instead of trying to reduce jet noise overall. The objective of the present project is to reduce large turbulence structures noise. It is the most dominant noise component radiating in the downstream direction. …

Alternative Method For Low Frequency Impact Sound Measurement For Building Field Tests, Sunit Girdhar

Dissertations, Master's Theses and Master's Reports

What do high heels, dog nails, and dragging furniture have in common? They are all frequent sources of noise pollution and annoyance in multi-story buildings. Building codes exist to control and mitigate such noise, but these codes are outdated and fail to protect the residents against noise annoyance. Footstep noise is still the number one cause of complaints among the residents. The impact performance of floor-ceiling assemblies is characterized using a single-number rating called the Impact Sound Rating (ISR). A standard tapping machine is used in pre-defined locations on the floor and the radiated Sound Pressure Level (SPL) is measured …

Passive Earplug Including Helmholtz Resonators Arranged In Series To Achieve Broadband Near Zero Occlusion Effect At Low Frequencies, Kevin Carillo, Franck Sgard, Olivier Dazel, Olivier Doutres

Études primaires

The use of passive earplugs is often associated with the occlusion effect: a phenomenon described as the increased auditory perception of one's own physiological noise at low frequencies. As a notable acoustic discomfort, the occlusion effect penalizes the use and the efficiency of earplugs. This phenomenon is objectively characterized by the increase in sound pressure level in the occluded ear canal compared to the open ear canal. Taking inspiration from acoustic metamaterials, a new design of a three-dimensional printed “meta-earplug,” made of four Helmholtz resonators arranged in series, is proposed for achieving near zero objective occlusion effect measured on artificial …