Multidisciplinary Engineered Dynamic Systems

• FEA models of the surrogate fixture will be created.
• FEA models will be used to explore the critical design factors in understanding the relationship between the energy input location/direction and the damage produced at the unit under test.
• Modal analysis will be performed on the surrogate fixture and unit under test to validate the FEA models.
• A shaker test will be performed on the surrogate fixture to explore the effects of input location and drive file shaping on the strains and acceleration measured at the unit under test.

Confidential

Michigan Tech will test materials according to EN 29052-1. There will be two batches of testing. The first will consist of 10 baseline materials. The second batch will consist of 7 prototype materials. Each material will include averaging of data from three test samples. Dynamic stiffness from the EN 29052-1 test will be reported to the sponsor. In addition, damping values, using the half-power bandwidth method, will be reported for A-B comparisons. It should be noted that these damping values will not represent as-installed damping values for the materials. Finally, Michigan Tech will provide a load-deflection curve for each material based on results from an MTS machine test. Four of the baseline materials will also undergo a creep test, where they will be loaded over a 48 hour period and re-tested for dynamic stiffness. Data will be presented in the form of a 1-2 page report for each material, showing raw data and computed values of dynamic stiffness, damping ratio, and load-deflection.

This research is focused on development of innovative practical solutions for control of individual and multiple unmanned underwater vehicles (UUVs) and address challenges such as underwater communication and localization that currently limit UUV use. More specifically, the Nonlinear and Autonomous Systems Laboratory (NAS Lab) team are developing a rigorous framework for analyzing and controlling underwater gliders (UGs) in harsh dynamic environments for the purpose of advancing efficient, collaborative behavior of UUVs.

Underwater gliders are now utilized for much more than long-term, basin-scale oceanographic sampling. In addition to environmental monitoring, UGs are increasingly depended on for littoral surveillance and other military applications. This research will facilitate the transition between academic modeling/simulation problem solving approach to real-world Navy applications. The importance of this research is evident in the Littoral BattleSpace Sensing (LBS) Program contract at the Naval Space and Naval Warfare Systems Command for 150 underwater gliders, designated the LBS-G. These gliders will be operated by the Navy in forward areas to rapidly assess and exploit environmental characteristics to improve the maneuvering of ships and submarines and advance the performance of fleet sensors.

Research results will provide the coordination tools necessary to enable the integration of these efficient and quiet vehicles as part of a heterogeneous network of autonomous vehicles capable of performing complex, tactical missions. The objective is to develop practical, energy-efficient motion control strategies for both individual and multiple UGs while performing in inhospitable, uncertain, and dynamic underwater environments.

The specific goals of this project are twofold. The first goal is to design and fabricate a fleet of low-cost highly maneuverable lightweight underwater gliders. The second goal is to evaluate the capability of the single and multiple developed UGs in littoral zones. The proposed work will develop UGs that would share the buoyancy-driven concept with the first generation of gliders called “legacy gliders.” However, the NAS Lab UGs will be smaller in size, lighter in weight, and lower in price than legacy gliders. This will result in more affordable and novel UG applications. Moreover, the NAS Lab design to development approach allows for technological innovation that overcomes known challenges and responds to unexpected needs that arise during testing. Therefore, the significance of this research is that it will enable implementation of recently developed efficient motion planning algorithms, multi-vehicle coordination algorithms, and extension of these algorithms in realistic conditions where absolute location and orientation of each vehicle is not known and the time-varying flow field is not locally determined.

Introduction

There is a wide range of hydraulic extending-boom and knuckle-boom cranes in use on marine vessels. These cranes are often used in dynamic motion environments for cargo transfer and small boat handling. The ability to safely launch and recover small boats in elevated sea states for naval, Coast Guard and oceanographic purposes is currently a focus of investigation within these communities.

The purpose of this investigation is to extend the research begun under SBIR topic N06-

057, "Cargo Transfer from Offshore Supply Vessels to Large Deck Vessels" to improve the performance of hydraulic marine cranes in the dynamic offshore environment. In addition, the lessons learned during the development of the Integrated Rider Block Tagline System (IRBTS), the Platform Motion Compensation System (PMC) and the Pendulation Control System (PCS) for the rigid-boom, level-luffing marine cranes used for container handling on sealift ships will be incorporated into a final integrated, modular kit to improve cargo transfer with these extending-boom and knuckle-boom cranes.

Phase II Technical Objectives

The goal of Phase II is to develop and demonstrate a modular solution for crane pendulation and motion control suitable for a wide range of existing U.S. Navy ship cranes. Phase I clearly showed that pendulation control can be modularized by implementing ship motion cancellation using the crane's existing drive system and active load damping using a retrofit damping device. In that work, a specific crane design was considered and the study was strictly proof-of-concept through simulation.

Phase II focuses on identifying the range of cranes for which the modular approach is feasible, developing the analysis and design work flow needed to design and deploy the modular solution, and demonstrating both the process and the performance on a particular crane. The incremental technical objectives of Phase II are listed below.

1. The analysis and design process for implementing modular pendulation and motion control on any crane,

2. The development of a modular crane control system (MCCS) "kit" including refinement of the key subsystems (sensors, actuation, algorithms),

3. A phased demonstration of MCCS using 1/12^th and larger scale testbeds.

At the conclusion of Phase II, the objective is to have a fully functioning MCCS system demonstrating ship motion cancellation, active payload damping on an articulated crane similar to those currently deployed on numerous U.S. Navy and civilian ships. The Phase II Option will focus this development on a design that can be implemented on the hydraulic extending-boom crane, currently proposed for use on the JHSV.

Overview:

Design optimization of cyber-physical systems (CPS) includes optimizing the system architecture (topology) in addition to the system variables. Optimizing the system architecture renders the dimension of the design space variable (the number of design variables to be optimized is a variable.) This class of Variable-Size Design Space (VSDS) optimization problems arises in many CPS applications including (1) microgrid design, (2) automated construction, (2) optimal grouping, and (3) space mission design optimization.

Evolutionary Algorithms (EAs) present a paradigm for statistical inference that implements a simplified computational model of the mechanisms embedded in natural evolution, with potential to solve this problem. However, existing EAs cannot optimize among solutions of different architectures because of the inherent strategy for coding the variables in EAs. Existing EAs resembles natural evolution in which a given architecture can evolve by improving the state of its variables but cannot be revolutionized. Inspired by the concept of hidden genes in biology, this project investigates revolutionary optimization algorithms that can optimize among different solution architectures and autonomously develop new architectures that might not be known a priori, yet are more fit solution architectures. Efficacy of the new algorithms for CPS is evaluated in the context of space mission design optimization.

Intellectual Merit:

There is an increasing demand in the scientific community for autonomous design optimization tools that can revolutionize systems designs and capabilities. Most existing optimization algorithms can only search for optimal solutions in a fixed-size design space; and hence they cannot be used for solution architecture optimization. Few existing algorithms can search for optimal solutions in VSDS problems; however these are problem-specific algorithms and cannot be used as a general framework for VSDS optimization. This project investigates the novel concept of hidden genes in coding the variables in evolutionary algorithms so that the resulting algorithms can be used for optimizing VSDS problems. The key innovation in these new algorithms is the new coding strategies. In addition, in this project, the standard operations in EAs will be replaced by new operations that are defined to enable revolutionizing a current population of solution architectures using the new coding strategy. The Pl's recent research results, in the context of space mission design optimization, demonstrate that the hidden genes optimization algorithms can search for optimal solutions among different solution architectures, revolutionize an initial population of solutions, and construct new solution architectures that are more fit than the initial population solutions.

Overview:

Injuries and fatalities occur every year when mine workers are struck and pinned by mobile haulage equipment in underground and surface mines. To prevent these accidents, the mining industry is beginning to adopt proximity detection systems to this class of equipment. These systems use various technologies, such as RFID, RADAR, infrared and others. The problem with this adaptation is that manufacturers are designing systems without sufficient scientific investigation to determine all of the parameters. NIOSH intends to conduct a thorough investigation of these accidents and develop innovative technology that will increase workers safety around mobile haulage equipment.

One of the first steps in this endeavor will be to determine the vehicle dynamics for the majority of mobile haulage equipment. Characteristics such as acceleration, tractive effort, braking, steering, and other parameters are examined in conjunction with human motion data to create 3D computer simulations.

Because of time and resource constraints, NIOSH is exploring the possibility of acquiring the vehicle operating dynamics parameters through an outside contract. The contractor would be required to become familiar with multiple types of mine haulage equipment. The calculated dynamics should be applicable to all machines of each type. NIOSH could provide some limited information on this equipment, but the majority would have to be acquired by the contractor. The majority of contract work consists of calculating and determining vehicle dynamics for the various types of mine haulage.

Task 1: Create a database detailing available the types of mine haulage equipment available. This database details the equipment manufacturers, their model types, and usage. Collect necessary physical and operational data about each identified type of mine haulage equipment in order to categorize them and provide a minimum set of vehicles to dynamically model.

Task 2: In order to model a particular machine type, a representative construct needs to be given dimensions and weight distributions similar in nature to all machines in that machine type category. Using the database compiled, specifically the physical data collected and develop a representative construct for each category identified in the previous task from the collected mine haulage equipment physical characteristics.

Task 3: Determine the vehicle kinematics and dynamics for the majority of mobile haulage equipment that fit into each category. Characteristics such as acceleration, tractive effort, braking, steering, and other parameters are determined and mathematical modeling of associated equations of motion generated for each construct. It is expected that the equations of motion in the derived construct mathematical models can be used to simulate these various machine types in a simulation software package such as Jack.

Introduction/ Abstract

Torque converter torus designs have evolved from axially long and round shapes to axially thin and elliptical shapes as automatic transmission content has increased in numbers of gears and in damping capability of the torque converter clutch. Future designs will include torque converters with even thinner tori with the torque converter to be used strictly as a vehicle launch device and the converter clutch applied in low gear at low vehicle speed. These changes result in improved vehicle fuel economy, however, thinner torus torque converters are at increased risk for high levels of cavitation. The fluid in a small torus torque converter versus large at the same level of torque has greater pressure gradients across the blades of the converter pump, turbine, and stator. Greater pressure gradients result in lower pressures on the low pressure side of converter element blades which can lead to cavitation. Smaller torus converters also contain less transmission fluid which can lead to localized regions of higher temperature, further contributing to increased risks for high levels of cavitation. Understanding torque converter cavitation and noise characteristics, and the Influences of design parameters and operating conditions on cavitation level is vital to enabling new generations of transmission designs.

This research seeks to build upon knowledge gained from previous torque converter cavitation and noise studies executed at MTU. Previous research has established that moderate levels of cavitation are present in many torque converters under normal operating conditions. This research intends to quantify the level of cavitation present under normal and overload operating conditions and to develop a method to compare designs relative to design parameters and loading.

Introduction

Starting in 1997, extensive research was conducted into techniques for detecting the presence of cavitation in the flow field of an operating torque converter. These studies have produced novel methodologies for sensing the onset of cavitation and quantifying its intensity at various operating conditions using microwave telemetry and specially instrumented torque converters. In 2000, a separate project was undertaken to develop a technique to acquire and evaluate noise generated by a torque converter during operation using acoustic measurements. Large quantities of data were acquired in both vehicles and in the dynamometer lab, advanced software was used to disassemble the noise spectrum into its critical components. Very successful measurement and analysis methodologies were developed, but no attempt was made to utilize these tools on converters of widely different sizes and designs. In 2004, a project was undertaken in which converters of different sizes and designs were operated over a range of charge pressures and torques at the stall operating condition. Noise data was acquired during the tests, processed by the recently developed numerical techniques, and non-dimensionalized or otherwise correlated against the converter's design and load parameters. The acoustical method of cavitation sensing was employed to similarly define the influence of converter design on cavitation potential. This data was used to validate the dimensional analysis approach to cavitation prediction suggested by the earlier work. To provide the precision and repeatability necessary for testing performed, both the dynamometers and hydraulic system of the test facility were updated to full computer control. The body of work has nicely correlated the cavitation characteristics of torque converters at stall conditions. In 2007, a project was initiated to characterize torque converter cavitation through a range of speed ratio operation and normal input torque and power levels. Test data was analyzed to develop dimensionless models to predict the speed ratio for cavitation desinense based on torque converter design parameters and operating conditions.

The research established that moderate levels of cavitation are present with no adverse effects in many production torque converters functioning under normal operating conditions. There are no complaints of objectionable noise from cavitation and no evidence of material wear or damage due to the implosion of cavitation bubbles. As torque converter torus designs continue to get smaller, this may no longer be the case. This study proposes to develop a method to measure and quantify the level of cavitation in a torque converter, determine criteria for acceptable levels of cavitation, test a matrix of torque converter designs for cavitation, and perform dimensional analysis to create a model capable of predicting cavitation level based on design parameters and operating conditions