Technical Description
The test apparatus design and project description are provided in the following subsections The motivation behind the project is developed and the desired goals are stated.
Introduction
Spacecraft attitude control is a crucial subsystem essential for the longevity and success of a spacecraft mission It significantly influences various mission requirements, including solar power generation, communication signal maintenance, altitude and attitude control, and the thermal management of key components Underestimating the importance of these functions can lead to mission failure, as even minor stabilization issues can compromise image clarity and render expensive missions ineffective Consequently, the space industry requires highly reliable, efficient, and cost-effective attitude controllers customized for specific mission needs.
In general, all spacecraft attitude control systems implement the principle of conservation of angular momentum to stabilize the spacecraft against disturbance torques
Conventional attitude controllers like Control Moment Gyros (CMGs) generate momentum for spacecraft through rapid rotor spinning In contrast, Fluidic Momentum Controllers (FMCs) offer significant advantages, including their lightweight and compact design, making them suitable for a wider range of spacecraft missions Additionally, the fluid loop radius of an FMC can be adjusted to meet the specific requirements of different spacecraft and missions.
Fuzzy Model Control (FMC) systems can be effectively utilized in the burgeoning micro- and nano-satellite technology sector, which is gaining traction due to the cost advantages of launching smaller, lighter spacecraft However, the inherent size and weight constraints of these satellites pose challenges for the integration of traditional control systems, making FMC an ideal solution for their design and operation.
A possible solution to the lack of such a major subsystem could be FMCs Increased research is required if that is to be achieved.
FMCs offer several advantages, including enhanced energy efficiency due to their design, which features a sufficiently large fluid loop radius that reduces the need for high rotational velocity and system mass Unlike CMGs, which often rely on complex multi-unit systems to generate adequate control torque and require vibration isolation platforms due to their high energy density operation, FMCs can function effectively at a low energy density Positioned on the spacecraft's periphery, FMCs transmit minimal vibration to the structure, making them more efficient per unit mass.
The auxiliary functions of the Fluid Management System (FMC) can offer significant advantages, such as the ability of water to absorb excess waste heat generated by the spacecraft Additionally, the extensive surface area of the piping can effectively serve as a radiator, facilitating the dissipation of surplus heat.
[Maynard, 1984] Also, by placing water reservoirs along the fluid loops, a secondary balancing effect could be created facilitating the primary function of active attitude control [Maynard, 1984].
The FMC is not only a theoretically viable solution but also an attractive practical option However, it has not undergone comprehensive research and development Initially conceived in the 1980s, the FMC concept remains dormant within the design plans of the Delta Space Station, failing to progress to manufacturing and testing stages.
FMC technology was previously constrained by the size and flow rate limitations of large spacecraft, but the rise of micro- and nano-satellites has opened up new market opportunities for its application.
Spacecraft attitude control technology is rapidly advancing, making it essential to enhance research in new control methods This focus on innovation is crucial for the ongoing development of space technologies.
Test Objectives
The FLOAT team aims to test a novel attitude control approach through the Fluid Loop Orientation/Attitude Test (FLOAT) in a microgravity environment The goal is to demonstrate the effectiveness of a Fluid Management Control (FMC) system, which could serve as a lightweight, economical, and efficient alternative to existing control methods A successful outcome is expected to encourage further research and development in FMC technology.
Test Description
Apparatus Design
The proposed testing apparatus is a free-flyer, as using a caged or gimbaled system would impose constraints that undermine the effectiveness of the control system performance test For additional details, refer to section 2.4.
The apparatus design features a transparent and lightweight cubic structure measuring 1 foot on each side, constructed from thin Lexan The cube's edges are sealed with rubber cushioning and hinged for safety, while all sharp edges are padded to protect crew members from injury To monitor the apparatus's attitude in real-time, an accelerometer is positioned at the center of each face Inside the cube, two 12-V batteries provide electrical power, and plastic fluid loops filled with water are mounted on all six faces, each completed with centrifugal pumps for efficient water containment.
The water is initially contained by plastic loops, which are subsequently covered with a thin plastic film to enhance protection for the electrical system Finally, the outer casing serves as the ultimate barrier, safeguarding the KC-135A cabin environment from any water intrusion.
Figure 1 Isometric View of Test Apparatus Preliminary Design
The data acquisitions, analysis, and control system hardware will be securely mounted in the center of the cube The six centrifugal pumps will be controlled by National
The Instruments (NI) FieldPoint (NIFP) is a modular, stand-alone distributed input/output system designed to control apparatus through a LabVIEW program It features built-in memory cards for data storage, allowing for data download to a personal computer (PC) post-flight of the KC-135A, eliminating the need for external computing systems during the flight.
The experimental hardware will not exceed 50 pounds in weight and will be secured to the floor of the KC-135A cabin during the climb and descent portions of the flight.
Ground Testing and Calibration
Before conducting flight tests, ground testing will be performed to calibrate the equipment by suspending the apparatus from each axis and running the pumps for a specified duration, during which angular rotation will be measured The accelerometer data may exhibit bias due to measurement inaccuracies, and this bias will be analyzed and minimized during ground testing Strategies for reducing accelerometer errors will be detailed in the Data Acquisition and Analysis section Once calibration is complete, the system will be prepared for flight testing.
After the design phase of the control software, a simulation will be developed to evaluate the FMC's response to different disturbances This iterative process aims to optimize the code prior to flight, offering valuable insights into anticipated results.
Data Acquisition and Analysis
NIFP, a stand-alone data acquisition system, will oversee data acquisition and manipulation for the FLOAT project It is designed to interface seamlessly with NI's LabVIEW software, which will serve as the primary tool for data manipulation throughout the project.
The FLOAT project aims to demonstrate the simultaneous control of yaw, pitch, and roll in a test apparatus using a fluid loop control system The primary experiment will be conducted to validate this innovative approach.
1 the test apparatus will be picked up from the floor of the cabin as microgravity begins,
2 the LabVIEW data acquisition and control programs will be initiated,
3 the test apparatus will be spun slowly to provide an initial disturbance, and
4 the test apparatus will be closely monitored to ensure the cube does not stray too far from the center of the cabin.
The project aims to develop a control system capable of restoring an apparatus to its original position within 20 seconds of microgravity after an initial disturbance Recognizing that free-flying experiments may only allow for a few seconds of unobstructed free-float, the primary objective is to demonstrate that the system can effectively respond to disturbances and make efforts to return the apparatus to its intended orientation.
Upon launching the LabVIEW program, real-time data from the accelerometers is collected and processed to determine position or angular rotation coordinates These coordinates serve as inputs for the control system, which manages the operation of the pumps The control system regulates the pumps' on and off durations, with longer activation periods resulting in larger rotation angles.
The test apparatus's orientation at any given moment is determined by the data collected from accelerometer readings These readings provide relative angular position data, indicating any overall changes in orientation The control system will correct these changes, while the accelerometers will persist in gathering data for future adjustments.
To assess the extent of rotation around each axis, it is essential to establish the connection between a stationary "inertial" reference frame located at the center of mass of the test apparatus and a reference frame that moves with the rigid body A visual representation of this problem is illustrated in Figure 2.
Figure 2 Top View of Test Apparatus with Reference Frames Defined
In the control problem illustrated in Figure 2, accelerometers are depicted as small rectangles on the cube's inner faces, focusing on the accelerations of points p x and p y To analyze the system, the velocity of point p x can be calculated based on the general angular velocity of the B frame relative to the A frame, denoted as ω AB.
In the rotating reference frame B, the first term on the right side of the equation becomes zero, leaving only the cross product term By differentiating this equation, we can derive the acceleration of point p x.
The result from evaluation of the right hand side gives x
After evaluating each of the terms on the right hand side, the general acceleration of point p x is achieved and is given by
Equation 4 is stated as the acceleration of the point p x as seen in the A frame coordinated in the B frame Similar expressions can be obtained for both point p y and p z on the other faces of the cube.
By applying constraints related to unidirectional accelerations, a solvable system of equations is established Accelerometers will be strategically positioned on the surfaces to exclusively measure the centripetal acceleration at specific points Consequently, each acceleration will align with the direction of the moment arm, meaning that the sensed acceleration in the i direction corresponds to r x This unidirectional condition simplifies the acceleration equations significantly.
The measured centripetal acceleration is represented on the left side of the equations, allowing for the resolution of a system comprising three equations with three unknowns: ω x, ω y, and ω z Once these angular velocities are determined, total rotation can be calculated through numerical integration The relative angular positions are expressed as x dt x = ∫ ω θ, θ y = ∫ ω y dt, and θ z = ∫ ω z dt.
These rotations will be used as inputs to a control system which will control the angular momentum produced by the fluid loops in the test apparatus.
When designing a controller, it is crucial to consider the angular acceleration of the system As shown in equations 4 and 5, accelerometers are unable to measure this angular acceleration directly However, since angular acceleration represents the rate of change of angular velocity over time, it can be numerically approximated By calculating angular velocity at two distinct time points, one can effectively estimate the angular acceleration.
To ensure an accurate control system, it is essential to address the biased and noise errors inherent in accelerometer measurements While error propagation is a common challenge in measurement systems, the FLOAT team aims to minimize these errors by utilizing two accelerometers positioned on opposite sides of the test apparatus By averaging the acceleration data from both sensors, the team can effectively reduce the impact of bias and noise Additionally, employing two accelerometers enhances system reliability; if one sensor fails, the second can still provide valuable data.
The calculated values of angular acceleration, angular velocity, and total angular change can now be utilized as inputs for a control system, enabling the application of reaction torques.
The basic conceptual design of the block diagram for the control system is provided below in Figure 3.
Figure 3 Basic Conceptual Controller Design, [Dorf, 2001]
The control system will apply necessary torques to realign the apparatus from its measured offset orientation to its original position This reorientation leverages the law of conservation of angular momentum, which connects the rate of change of angular momentum to torque Consequently, any alteration in the system's angular momentum results in an exerted torque, leading to a corresponding rotation The torque resulting from a change in angular momentum can be expressed mathematically as dt h.
Justification for the Microgravity Environment
Microgravity is imperative for conducting the performance test of the FMC
Gravitational torques are much larger than the torques that the FMC is design to counteract, therefore, testing of the FMC in 1-g becomes extremely difficult.
Simulations of the FMC in gravity have struggled to achieve the desired accuracy for collected data At The University of Texas, undergraduate students tested an apparatus using a helium balloon, which required a large volume and low weight to counteract gravity However, the balloon's substantial surface area created significant drag, complicating the experiment In contrast, the upcoming tests on the KC-135A will involve a much smaller spacecraft, minimizing drag effects Additionally, the fragile nature of the helium balloon made it unsuitable for rigorous testing.
Undergraduate students at UT developed a second apparatus featuring an air cushioning system to suspend a test object; however, this method was ineffective Challenges included maintaining an even air distribution over the test object while keeping the apparatus lightweight to avoid exceeding the reaction force from air pressure Ultimately, the limitations of the gravity environment led to the experiment's failure, as the controller could not be tested.
A gimbaled system is another potential option for a 1-g test, but it is impractical for use in a 1-g laboratory setting The pumps would struggle to generate enough angular momentum to counteract the torques caused by design asymmetries Even if more powerful pumps were employed to increase flow rates, issues such as cavitation in the loops could occur, leading to a stall effect.
Testing a fluidic control system (FMC) requires a microgravity environment to ensure accurate results This unique setting enables the evaluation of three axes while minimizing drag effects on the central body due to its small size To enhance our understanding of the fluidic control system, it is essential to conduct tests in the actual environment where the controller will be utilized.
Follow-Up Flight
To the FLOAT team’s knowledge, the experiment to be conducted has not previously been flown as a KC-135A microgravity project.
Safety Evaluation
The safety requirements of the RGFSOP have been addressed in the following subsections All subsystems possess minimal safety concerns.
Flight Manifest
The team is actively seeking a journalist to cover their flight experience, having reached out to News 8 Austin and the Austin American Statesman for assistance Once they receive final approval, they will proceed to contact the selection committee of the Reduced Gravity Student Flight Opportunities Program (RGSFOP).
Experiment Description
The Fluid Loop Orientation/Attitude Test (FLOAT) team is set to conduct a groundbreaking experimental performance test of a Fluidic Momentum Controller (FMC), focusing on both quantitative and qualitative analyses to explore an innovative attitude control system for satellites By utilizing fluid loops to manipulate angular momentum, FLOAT aims to counterbalance disturbance torques and sustain a desired satellite orientation The primary goal of this performance test is to showcase the capabilities of an automated FMC, marking a first in KC-135A microgravity research.
The testing of the apparatus will follow a straightforward and repeatable procedure, where a member of the FLOAT team will activate the control system and gradually spin the free-flying device during each parabola Continuous monitoring of the apparatus's motion will be conducted to avoid any collisions with obstacles Once the control system is engaged, it will capture all measurement data and real-time control decisions for quantitative analysis Additionally, the experiment will be recorded on video to facilitate further qualitative analysis of the results.
The FLOAT team strives to have their test apparatus return to its original position within 20 seconds However, it is recognized that in a free-flying experiment, achieving more than a few seconds of unobstructed free-float is challenging Consequently, a more attainable objective is to demonstrate that the controller can actively respond to disturbances and make efforts to regain its original orientation.
Equipment Description
Pumps
For the FLOAT project, the JABSCO model number 59500-0012 centrifugal pumps were selected after careful evaluation These pumps feature an internal impeller that efficiently accelerates fluid flow, making them ideal due to their compact size, lightweight design, and ability to provide high flow rates Additionally, the JABSCO pumps incorporate essential safety features, including a continuous fluid delivery rate of 15 liters per minute at 1.7 psi for up to 2,500 hours With 0.75-inch diameter inlet and outlet ports equipped with barbed connections, the risk of tubing disconnection is minimized Furthermore, the pumps are rated IP 53 and ISO 8846, indicating their ability to endure a 60-g shock and ensuring that the motor will not ignite surrounding gases.
The selected pump, as illustrated in Figure 4, measures 5.72 inches in length, 2.53 inches in height, and 3.13 inches in width, with a weight of 0.83 pounds It operates on a 12-V DC power supply, and to ensure safe operation and prevent overheating, a 2-A fuse will be installed to set an upper limit on the current.
The JABSCO pump, while currently the best design choice for the FLOAT project, presents a challenge due to its misaligned inlet and outlet ports, impacting the overall test apparatus design This misalignment has necessitated the use of non-circular plastic loops and a reduced radius, complicating the setup Despite these limitations, the FLOAT team remains open to exploring alternative pump options as they continue their search for a viable solution.
Accelerometers
National Instruments' Field Point (NIFP) hardware collects acceleration data using six single-axis accelerometers, which are securely attached to the center of each face of the test apparatus This strategic placement of accelerometers on adjacent faces enables NIFP to effectively detect rotation around any axis.
PCB Piezotronics' model 333B52 has been chosen as the ideal accelerometer for the project due to its compatibility, sensitivity, phase response, and durability This accelerometer outputs a biased voltage ranging from 7 to 12 Volts and is calibrated to 1000 mV per g, with a measurement range of ±5g It features a phase response of 2.5 to 3000 Hz, providing a suitable spectrum for the project's requirements Additionally, the model can withstand a maximum shock of ±4000 g, making it more than adequate for the conditions of the KC-135A.
The PCB accelerometer not only fulfills the data sensing requirements of the FLOAT project but also fits within its spatial constraints, measuring 0.45 inches by 0.68 inches by 0.45 inches Figure 5 below illustrates the chosen accelerometer.
Figure 5 PCB Piezotronics' Model 333B52 Accelerometer (magnified)
The FLOAT team is also currently in the process of researching Inertial Measurement Unit (IMU) gyros as an alternative to the use of accelerometers for attitude determination.
Structural Design
FMC Free-Flyer
The design of the test apparatus, illustrated in the provided CAD drawing, features a 1-foot cube constructed from 0.093-inch Lexan, chosen for its strength and transparency—being 250 times stronger than glass and 30 times stronger than acrylic To ensure safety, three edges of the cube are hinged for easy access, with zinc hinges bolted to prevent failure D-shaped rubber seals on the edges will prevent fluid leakage, while all sharp edges are padded for safety Each face of the cube houses a pump and fluid loop, with pumps positioned on opposite faces to create opposing angular momentum The fluid loops, made of polyester braided PVC hoses, are further protected by a plastic film to shield against leaks The pumps achieve a flow rate of 15 liters per minute for efficient operation, and a single-axis accelerometer on each face continuously monitors the structure's attitude Additionally, two rigid flat plates are secured within the cube, with one plate mounting the NIFP system and the other securing it, while motorcycle batteries are symmetrically positioned on opposing faces for balanced power supply.
Throughout the ascent and descent of the KC-135A, the test apparatus will be securely fastened to the aircraft's floor A designated flyer will oversee the apparatus's movements during every phase of the parabolic flight.
Alternative FMC Non-Free-Flyer
If the FLOAT project is not chosen as a free-flyer, an alternative method for testing the FMC in microgravity involves implementing a gimbaled system FLOAT aims to develop a gimbaling structure that will be securely anchored to the floor of the KC-135A.
Each of the three gimbals will be made from a lightweight metal, featuring a semi-rigid connection to the FMC test apparatus through a socket joint between two faces and the inner gimbal The z-axis post will incorporate a bearing with the outer gimbal, enabling near-frictionless rotation Additionally, the base of the post will include four bolt-down slots for securely anchoring the gimbaled structure.
The FLOAT team prefers a free-flyer experiment over a gimbaled system due to the increased moments of inertia and potential inaccuracies that arise from using near frictionless bearings and lightweight gimbals While minimizing friction is beneficial, any remaining friction can still distort results Additionally, testing a gimbaled system in a 1-g laboratory is problematic, as the weight of the components would significantly impact the outcomes Thus, a true free-flying experiment is deemed more viable for achieving accurate results.
Electrical System
FieldPoint
The control system will utilize the NIFP, a standalone modular distributed input/output system, with hardware centrally located within the cube structure LabVIEW will serve as the primary programming software for data acquisition and controller programs, which will be uploaded directly to the NIFP system, eliminating the need for a host computer in the FLOAT team's real-time embedded application.
The integrated system consists of individual modules, each with distinct specifications for input and output capabilities, housed within a backplane designed to accommodate four modules The FLOAT team's application necessitates three specific modules: a control module for LabVIEW software, a module for receiving acceleration data from accelerometers, and an output module for delivering pump commands This output module sends voltage commands to the pumps, controlling their operation for predetermined durations set by the controller Additionally, NI connector blocks will be utilized to seamlessly integrate the individual modules into a cohesive system.
Figure 6 Modular Design of FieldPoint Hardware
The electrical system for the FLOAT team's project, as illustrated in Figure 7, operates on a power source of 11- to 30-V DC with a minimum requirement of 15 W Power will be sourced from two 12-V DC motorcycle batteries, with one battery connected to the control module that filters and regulates power to individual modules The output module, responsible for supplying voltages to the pumps, may also require an additional 12-V battery The controller module processes accelerometer readings to calculate necessary torques and sends commands to the output module for pump control NIFP is designed to make real-time decisions at a frequency of 100 Hz, ensuring an adequate data sampling rate for the FLOAT team's needs.
NIFP will make real-time decisions while storing essential data on NI Compact Flash cards, including recordings of controller decisions, angular rates, and acceleration measurements It will also track the duration of voltage sent to the pumps, which will remain constant as the controller varies the pump activation time The FLOAT team is exploring the integration of sensors in the fluid flow to capture actual flow rates, despite expectations of a fixed constant, for future analysis After each KC-135A flight, all collected data will be downloaded onto a PC for comprehensive evaluation.
Pressure System
FLOAT will utilize JABSCO-manufactured centrifugal pumps to create fluid flow in the loops These pumps are designed for low pressure and high flow rates, significantly reducing the risk of tubing disconnection The maximum operating pressure is set at 2.9 psi, and exceeding this limit would cause the pump to shut down, preventing fluid supply The nominal operating pressure is 1.7 psi, ensuring that even during cabin depressurization, the pump system poses minimal pressure risks, making a relief valve unnecessary.
Laser System
No laser system will be implemented in the experiment.
Crew Assistance Requirements
No crew assistance will be needed for the experiment.
Institution Review Board
Hazard Analysis
A thorough examination of the FMC device indicates that it offers a safe alternative to other control methods, though potential hazards can arise with any device Table 1 outlines the anticipated hazards, their causes, potential consequences, and the strategies for addressing these issues.
Table 1 Possible Hazards from Test Apparatus Hazard Cause of Failure Ramifications Precautions and Solutions
Faulty connections between pumps and controller
Rubber bumpers on edges of satellite
Internal electrical system shut down
Pump failure - not responding to input
Loss of device Containment of electrical system within satellite Hazardous to flight conditions Fire suppression system
Pressure too high Short in electric system Thin plastic film wrapped around hoses
Faulty connection between pump and hose
Possible leakage to environment of fluid
Seal placed around the outside edge of satellite
Depressurization Low pressure pumps are used
Reinforced connections Working fluid is water
Faulty manufacturing Short in electric system Thin plastic film wrapped around hoses
Kink in hose Possible leakage to environment of fluid
Seal placed around the outside edge of satellite
Braided tubing used Faulty manufacturing
Thin plastic film wrapped around hoses
Possible leakage of acid to environment
Hose blow-out at connection to pump
Loss of control Collision with the walls or other experiments
Fire Faulty connection between battery and devices
Tool Requirements
The test apparatus will be relatively simple, and will require the use of only a few construction/maintenance materials A list of the expected materials is provided below.
5 Wire cutters and wire stripper
Ground Support Requirements
Ground support will not be necessary, as all testing will be performed in laboratories at The University of Texas at Austin before the team departs for Houston A final verification will take place upon arrival in Houston to confirm that all system components are functioning correctly.
Hazardous Materials
The FMC loops utilize water as the working fluid, eliminating the presence of raw hazardous materials However, the system incorporates a wet cell battery that relies on a dilute sulfuric acid solution for electricity generation, posing a risk in case of acid leakage Additionally, the battery contains small amounts of other hazardous substances, including lead, lead oxide, and anglesite To mitigate these risks, FLOAT has implemented safety measures such as a containment layer within the test apparatus and seals around each face to prevent exposure to the environment in the event of a leak For further information, the Material Safety Data Sheet (MSDS) for a representative battery is available in Appendix C.
Procedures
Ground Operations
1 Arrive in Houston and proceed to Ellington field.
3 Complete any further pretest requirements.
4 Test general system functionality. a Test electrical system. b Perform accelerometer data acquisition test. c Test controller and feedback functionality.
5 Confirm no liquid leak issues exist.
6 Perform thorough cleaning of apparatus.
Pre-Flight
1 Load the test apparatus onto the KC-135A.
2 Strap the cube to the floor of the aircraft.
3 Make final preparations for flight, such as charging camera/pump batteries.
In-Flight
1 Turn on the electronic components.
3 Prepare video camera for recording of experiment.
2 Pick apparatus up off the floor as microgravity begins.
3 Implement program to provide automatic control and pointing of test object. a Acquire initial conditions of attitude. b Maintain initial conditions after the application of several random disturbances through feedback control of system.
No experimentation will be conducted in the High-gravity phase.
Post-Flight
2 Shutdown all electronic components and secure system for landing.
1 Transfer all experiment data to an external hard drive for backup and storage.
2 Prepare the test equipment for next day’s flight.
Outreach Plan
The Fluid Loop Orientation/Attitude Test (FLOAT) team’s outreach plan for the 2003-2004 academic year will target a diverse audience
FLOAT aims to inspire the youth in the local community by promoting educational advancements through guided instruction While engineering is a key focus, the organization is also committed to fostering inspiration in various scientific fields, ensuring a well-rounded approach to education and innovation.
General Audiences
University of Texas at Austin Outreach Events
The FLOAT team is set to participate in the Centennial of Flight, an event organized by the UT Aerospace Engineering department to celebrate 100 years of aviation This event will bring together students and faculty from across the University of Texas, coinciding with the engineering homecoming weekend at UT-Austin The FLOAT team will showcase their project at a dedicated booth and will be available to answer any questions Additionally, the Explore UT event will serve as an open house for the university, offering further opportunities for engagement.
The upcoming event offers alumni and prospective students an opportunity to explore the activities of current students in the UT ASE department, highlighting the innovative FLOAT project to a broad audience.
The FLOAT team aims to showcase an overview of their project to a broad and varied audience, with the objective of promoting research initiatives developed within the ASE department across the entire campus.
Science and Engineering Specific Events:
The FLOAT team will conduct specialized presentations for engineering disciplines, merging the excitement of microgravity experiments with the underlying science and engineering concepts On October 8, 2003, they presented to the University of Texas Freshman Interest Group (FIG) for Aerospace Engineering, which comprises around 30 new students in the department This presentation aimed to inform incoming freshmen about potential activities and projects they could engage in Additionally, the team is scheduled to present at the External Advisory Committee (EAC) meeting during a luncheon on October 23.
The Aerospace Engineering Department will host representatives from the aerospace industry and government laboratories, facilitating valuable interactions between students and industry professionals This committee aims to enhance collaboration with other engineering and science groups, such as EUREKA (Enhancing).
Undergraduate Research Knowledge, and Access), SURGe (Science Undergraduate Research Group), and AIAA (American Institute of
The FLOAT team aims to showcase their projects at the FIG and AIAA meetings, fostering interest among students in the ASE department By highlighting the exciting opportunities available, they hope to inspire participation in future KC-135A projects Additionally, presenting to the External Advisory Committee will allow the team to demonstrate their work to a knowledgeable audience and gain valuable insights for further applications of an FMC.
Please see the letters from Aerospace Engineering Undergraduate
Coordinator, Gail Simpler, and AIAA Chapter President, Marcin Lenart, outlining our involvement in these events The letters are attached in Appendix B in the hard copy version of this document.
Houston Museum of Natural Science
The FLOAT team has coordinated with a member of the Youth
In spring 2004, the Education Department at the HMNS will host a trip to the museum, featuring a display in the Discovery Place section to showcase and demonstrate the FLOAT project Interactive demonstrations will highlight angular momentum generation systems, including a bicycle wheel, a rotating stool, and a hydro gyro, allowing visitors to experience the forces of angular momentum firsthand Additionally, the FLOAT team will present a model of the experiment and use a laptop to display CAD drawings, illustrating the project's evolution from a digital design to a physical object.
The Discovery Place, situated in a family-friendly area of the museum, provides an excellent opportunity for the FLOAT team to engage with numerous children during their visit to the HMNS By utilizing interactive presentation materials, the team aims to spark children's interest in science and encourage a love for learning.
Please see the letter from the HMNS attached in Appendix B in the hard copy version of this document.
The Science Place
FLOAT is planning a visit to The Science Place in Dallas, which aims to inspire a passion for science through exploration, discovery, and lifelong learning This trip presents an excellent opportunity for the FLOAT team to engage with children and students in the Dallas area They will utilize the same demonstration materials from their presentation at the Houston Museum of Natural Science for this event.
The Science Place aims to engage with the youth in the Dallas area, fostering a passion for science and mathematics Through interactive experiences, the initiative seeks to inspire young minds and encourage them to explore these critical fields.
Please see the email John Campbell of The Science Place in Appendix B in the hard copy version of this document.
Primary and Secondary School Outreach Activities
The FLOAT team aims to engage a diverse audience through museum presentations while also reaching students directly by visiting local science classes By traveling to schools, they will demonstrate angular momentum concepts and foster one-on-one interactions with students and teachers Utilizing the same materials from museum trips for these school demonstrations, the team believes that personal involvement is key to sparking interest in science and engineering among kids They have already established contact with several local schools for this initiative.
Patricia Nunez, Science Teacher, Sims Elementary School
Liz Liles, Science Teacher, Covington Middle School
-contact made and presentation dates in work
Leigh Houston, Physics Teacher, Cedar Park High school
-contact made and presentation dates in work
A member of the FLOAT team will visit James Martin High School in Arlington, Texas, to present the FLOAT project Jay Atman, a representative from the school, has coordinated this opportunity for the FLOAT team to engage with students during a class period.
The primary goal of the school visits is to inspire students' enthusiasm for science through engaging and interactive presentations By utilizing fun and educational demonstration materials, the team aims to capture students' interest while ensuring the content is tailored to their age and technical understanding.
Please see the emails from Jay Atman and Patricia Nunez in Appendix B in the hard copy version of this document.
Publications
The FLOAT team is actively engaging with local media to promote their project, including planned presentations at schools and museums The University of Texas engineering newsletter, The Vector, has committed to featuring an article on the FLOAT team's proposal in its upcoming edition, with a follow-up planned if the project is accepted Additionally, the FLOAT team is in discussions with the Austin American Statesman about publishing an article upon their acceptance to fly.
Please see the letter and rough draft of news article from Emily Burrough of the Vector, in Appendix B in the hard copy version of this document.
-Objective: To allow general engineering student to become familiar with the project in hopes of expanding interests in the KC-135A program.
Team Webpage
The team webpage has been created but is still under construction The address to the webpage address is: http://libra.ae.utexas.edu/research/float/
The UT ASE computer lab is in the process of migrating all Unix accounts to Linux servers While the current link remains active, it may change before this section is reviewed The FLOAT team will ensure that any updates to the web address are communicated to the program office.
The FLOAT team's webpage will be regularly updated with the latest news, photos, and events throughout the year Attendees of FLOAT-hosted outreach events will receive documentation that includes the team's website address.
The documentation aims to promote awareness of the team and serve as a convenient source for FLOAT updates After the proposal is submitted to the RGSFOP, it will be made available for viewing on the website.
-Objective: The webpage’s purpose is primarily to increase the FLOAT project visibility across the world.
Administrative Requirements
FLOAT acknowledges the importance of adhering to NASA's compliance requirements, including program timelines, deadlines, and information requests, to ensure a successful RGSFOP experience The FLOAT team is committed to meeting these requirements and any additional requests from NASA.
Institution’s Letter of Endorsement
Attached in Appendix A of the hard copy document is a letter from Dr Robert Bishop, the chairman of the Department of Aerospace Engineering and Engineering Mechanics.
Supervising Faculty Statement
Please see the statement from the FLOAT team’s faculty advisor, Dr Robert Bishop The statement is attached in Appendix A to the hard copy version of this document.
Budget
An analysis of the approximate funds to complete the evaluation of the FMC as part of RGSFOP is found in Table 2.
Table 2 Estimated Budget for Texas FLOAT Project Item Quantity Per Unit Cost Total Cost Current Funding
Lexan 3 $ 19.98 $ 59.94 $ - Hinges 3 $ 1.99 $ 5.97 $ - Braided Reinforced PVC Hoses 2 $ 6.86 $ 13.72 $ -
Outside Seal 2 $ 4.77 $ 9.54 $ - Rubber Bumpers 6 $ 5.00 $ 30.00 $ - Thin Plastic Layer 6 $ 3.00 $ 18.00 $ - Mounting Hardware 1 $ 20.00 $ 20.00 $ - University of Texas Sticker 1 $ 4.00 $ 4.00 $ -
NI Compact FieldPoint 1 $ 1,000.00 $ 1,000.00 $ - Video Camcorder 1 $ 1,500.00 $ 1,500.00 $ 1,500.00 Laptop (Ground Analysis) 1 $ 2,000.00 $ 2,000.00 $ 2,000.00 Gasoline 1 $ 50.00 $ 50.00 $ - Hotel 10 $ 50.00 $ 500.00 $ - Food 75 $ 5.00 $ 375.00 $ - Materials 1 $ 150.00 $ 150.00 $ - Travel Expenses 2 $ 100.00 $ 200.00 $ - Hotel 3 $ 50.00 $ 150.00 $ -
The total budget required for the project is $7,842.17, of which we have secured $3,500.00 in contributions These contributions include a laptop and a video camera generously donated by The University of Texas at Austin’s Department of [specific department name].
Aerospace Engineering and Engineering Mechanics involve approximate values for travel expenses and outreach initiatives The hardware budget has been estimated based on our preliminary design, utilizing resources from Home Depot and various online sources.
Funding
The University of Texas's Department of Aerospace Engineering is committed to significantly funding the FLOAT team, with National Instruments, a key partner, eager to support undergraduate research by potentially donating the Compact FieldPoint system, as they have previously provided equipment for UT's KC-135A projects If selected for flight, the FLOAT team plans to seek additional equipment donations from pump manufacturer JABSCO and will also reach out to the Texas Space Grant Consortium for further funding The department maintains strong connections with industry representatives from Boeing, enhancing collaboration opportunities.
Company and Lockheed Martin Corporation, two potential sources for funding The FLOAT team is confident that all expenses will be covered.
Institutional Review Board
Institutional Animal Care and Use Committee
Parental Consent Forms
Appendix A: Institution’s Letter of Endorsement and
Appendix B: Outreach Letters of Committal
Appendix C: Specification Sheets for Various Components
Appendix D: MATLAB Moment of Inertia and Angular
Baseline calculations were computed in MATLAB to determine the viability of the FMC Based on these calculations, the angular displacement achievable in 20 seconds is
32.2848 θ with angular momentum generated by the fluid loops of lbf
The code that generated these results is seen below.
%Brad Steinfeldt and Amanda Kelly
%The geometry set up is as follows:
%A hollow cube with a fluid loop on the top and bottom face of the cube
%The 6 pumps are located on the faces as shown below
% Top Face (looking down from top)
% Bottom Face (looking down from top)
% Left Face (looking from the left of cube)
% Right Face (looking from the left of cube)
% Front Face (looking from the front of cube)
% Back Face (looking from the front of cube)
%The coordinate axis for the problem is defined to be:
%X-Axis: Out the right face
%Y-Axis: Out the front face
%Z-Axis: Out the top face
%This program assumes the following:
% 2) The working fluid is evenly distributed mass inside of a torus
% 3) The mass distribution of the plates is even
% 4) The pumps are modeled as rectangular prisms with constant density (probably
% 5) The connection between the fluid loops and the pumps are done at the end of
% 6) The batteries are massless (BAD assumption)
% 7) The circuit board is massless
% 8) The tubes are negligible in mass
%The working fluid for the problem is water using a Jabsco 59500 Pump
% X-Axis: Through center of mass and out the right face
% Y-Axis: Through center of mass and out the top face
% Z-Axis: Through center of mass and out the front face
% c=radius from the center to the center of the cross sectional area
% a=radius of the cross section (i.e the circle that is revolved)
% X-Axis: A symmetric axis through center of mass
% Y-Axis: A symmetric axis through center of mass
% Z-Axis: Through the center of mass and up
%innertube=inner diameter of tubing
%outertube=outer diameter of tubing
%innerloop=inner radius of loop
%outerloop=outer radius of loop rhofluidb.3707; rhofacet.3; pumpmass=.8; lpump=5.75/12; hpump=2.5/12; wpump=(3+3/8)/12; lface=1; dface=.125;
%Bottom Face Inertia (local frame, looking from top of box, x-right, y-down, z-out)
Ibottomface(1,1)=Ibottomface(1,1)+1/12*massofface*(lface^2+dface^2);
Ibottomface(2,2)=Ibottomface(2,2)+1/12*massofface*(dface^2+lface^2);
Ibottomface(3,3)=Ibottomface(3,3)+1/12*massofface*(lface^2+lface^2);
%Front Face Intertia (local frame, looking from top of box, x-right, y-down, z-out) Ifrontface=zeros(3,3);
Ifrontface(1,1)=Ifrontface(1,1)+1/12*massofface*(dface^2+lface^2);
Ifrontface(2,2)=Ifrontface(2,2)+1/12*massofface*(lface^2+lface^2);
Ifrontface(3,3)=Ifrontface(3,3)+1/12*massofface*(lface^2+dface^2);
%Back Face Inertia (local frame, looking from top of box, x-right, y-down, z-out)
%Left Face Intertia (local frame, looking from top of box, x-right, y-down, z-out) Ileftface=zeros(3,3);
Ileftface(1,1)=Ileftface(1,1)+1/12*massofface*(lface^2+lface^2);
Ileftface(2,2)=Ileftface(2,2)+1/12*massofface*(lface^2+dface^2);
Ileftface(3,3)=Ileftface(3,3)+1/12*massofface*(dface^2+lface^2);
%Right Face Inertia (local frame, looking from top of box, x-right, y-down, z-out)
%Top Torus Inertia (local frame, looking from top of box, x-right, y-down, z-out) Itoptorus=zeros(3,3); c=(outerloop-innerloop)/2; a=innertube/2;
Itoptorus(1,1)=Itoptorus(1,1)+1/8*((5*a^2+4*c^2))*rhofluid*2*pi^2*a^2*c^2; Itoptorus(2,2)=Itoptorus(2,2)+1/8*((5*a^2+4*c^2))*rhofluid*2*pi^2*a^2*c^2; Itoptorus(3,3)=Itoptorus(3,3)+(3/4*a^2+c^2)*rhofluid*2*pi^2*a^2*c^2;
%Bottom Torus Inertia (local frame, looking from top of box, x-right, y-down, z-out)
%Back Torus Inertia (local frame, looking from top of box, x-right, y-down, z-out) Ibacktorus=zeros(3,3); c=(outerloop-innerloop)/2; a=innertube/2;
Ibacktorus(1,1)=Ibacktorus(1,1)+1/8*((5*a^2+4*c^2))*rhofluid*2*pi^2*a^2*c^2; Ibacktorus(2,2)=Ibacktorus(3,3)+(3/4*a^2+c^2)*rhofluid*2*pi^2*a^2*c^2;
Ibacktorus(3,3)=Ibacktorus(2,2)+1/8*((5*a^2+4*c^2))*rhofluid*2*pi^2*a^2*c^2; Ibacktorus;
%Front Torus Inertia (local frame, looking from top of box, x-right, y-down, z-out)
%Left Torus Inertia (local frame, looking from top of box, x-right, y-down, z-out) Ilefttorus=zeros(3,3); c=(outerloop-innerloop)/2; a=innertube/2;
%Right Torus Inertia (local frame, looking from top of box, x-right, y-down, z-out)
%Top Pump Inertia (local frame, looking from top of box, x-right, y-down, z-out)
Itoppump(1,1)=Itoppump(1,1)+1/12*pumpmass*(lpump^2+hpump^2);
Itoppump(2,2)=Itoppump(2,2)+1/12*pumpmass*(wpump^2+hpump^2);
Itoppump(3,3)=Itoppump(3,3)+1/12*pumpmass*(lpump^2+wpump^2);
%Bottom Pump Inertia (local frame, looking from top of box, x-right, y-down, z-out)
%Left Pump Inertia (local frame, looking from top of box, x-right, y-down, z-out)
Ileftpump(1,1)=Ileftpump(1,1)+1/12*pumpmass*(lpump^2+wpump^2);
Ileftpump(2,2)=Ileftpump(2,2)+1/12*pumpmass*(hpump^2+lpump^2);
Ileftpump(3,3)=Ileftpump(3,3)+1/12*pumpmass*(hpump^2+wpump^2);
%Right Pump Inertia (local frame, looking from top of box, x-right, y-down, z-out)
%Front Pump Inertia (local frame, looking from top of box, x-right, y-down, z-out)
Ifrontpump(1,1)=Ifrontpump(1,1)+1/12*pumpmass*(lpump^2+hpump^2);
Ifrontpump(2,2)=Ifrontpump(2,2)+1/12*pumpmass*(wpump^2+lpump^2);
Ifrontpump(3,3)=Ifrontpump(3,3)+1/12*pumpmass*(wpump^2+hpump^2);
%Back Pump Inertia (local frame, looking from top of box, x-right, y-down, z-out)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% dx=0; dy=0; dz=(lface-dface)/2;
The matrix I is updated by incorporating contributions from the bottom face and the mass of the face The first row accounts for the diagonal element I(1,1) with an addition of mass-related terms, while I(1,2) and I(1,3) are adjusted negatively Similarly, the second row modifies I(2,1) and I(2,3) negatively, while I(2,2) includes a positive adjustment In the third row, I(3,1) and I(3,2) are also adjusted negatively, with I(3,3) receiving a positive contribution The final matrix I reflects these updates, ensuring accurate representation of the system's dynamics.
%Top face dx=0; dy=0; dz=-(lface-dface)/2;
The matrix I is updated based on the contributions from the top face and the mass of the face The first row adjusts the first element by adding Itopface(1,1) and the product of the squared differences in y and z dimensions multiplied by massofface, while the second and third elements are negatively influenced by the products of dx with dy and dz, respectively In the second row, the first and third elements are similarly updated negatively, while the second element sees a positive adjustment with Itopface(2,2) and the sum of the squared differences in x and z dimensions The third row follows a similar pattern, with the first and second elements being negatively impacted by the products of dz with dx and dy, and the third element positively adjusted by Itopface(3,3) along with the sum of squared differences in x and y dimensions.
%Left face dx=(lface-dface)/2; dy=0; dz=0;
The matrix I is updated based on the contributions from the left face and the mass of the face, with specific calculations for each element For the first row, the first element increases by the mass contribution, while the second and third elements are adjusted negatively The second row follows a similar pattern, with the first and third elements decreasing and the second element increasing The third row also features negative adjustments for the first two elements, while the last element increases These calculations incorporate the dimensions dx, dy, and dz, ensuring a comprehensive update of the matrix I based on the surrounding face interactions and mass.
%Right face dx=-(lface-dface)/2; dy=0; dz=0;
The matrix I is updated by adding contributions from the right face and mass, with specific calculations for each element For I(1,1), the value is incremented by the right face and the product of mass and the sum of the squares of dy and dz In contrast, I(1,2) and I(1,3) are adjusted by subtracting the right face values along with mass contributions from the products of dx and dy, and dx and dz, respectively The second row, I(2,1) and I(2,3), follows a similar pattern of subtraction, while I(2,2) is updated positively by adding the right face value and mass contributions from the sum of the squares of dx and dz Lastly, the third row sees I(3,1) and I(3,2) decreased by the right face values combined with mass contributions from the products of dz and dx, and dz and dy.
%Front face dx=0; dy=-(lface-dface)/2; dz=0;
%Back face dx=0; dy=(lface-dface)/2; dz=0;
%Bottom Loop dx=0; dy=0; dz=lface/2-outertube/2-dface;
I; dx=0; dy=0; dz=-(lface/2-outertube/2-dface);
The matrix I is updated based on the contributions from Itoptorus and the mass of the loop, incorporating the squared differences in dimensions The first row adjusts I(1,1) positively while I(1,2) and I(1,3) are modified negatively to account for the interactions with dy and dz, respectively In the second row, I(2,1) and I(2,3) are also negatively impacted, while I(2,2) receives a positive update The third row sees I(3,1) and I(3,2) decrease, while I(3,3) increases due to the contributions from Itoptorus and the squared differences in dx and dy Overall, these calculations reflect the dynamic interplay of forces acting on the system.
%Back Loop dx=0; dy=lface/2-outertube/2-dface; dz=0;
The matrix I is updated based on the contributions from the backtorus matrix and the mass of the loop, incorporating the squared differences in dimensions Specifically, the first row of matrix I is adjusted by adding the influence of Ibacktorus and the product of massofloop with the squared differences of dy and dz for the first element, while the second and third elements are modified with negative contributions The second row follows a similar pattern, with the second element gaining from the squared differences of dx and dz, while the other elements are adjusted negatively The third row reflects the same methodology, with the last element incorporating the squared differences of dx and dy This systematic approach ensures that the matrix I accurately represents the physical interactions dictated by the loop's mass and dimensions.
%Front Loop dx=0; dy=-(lface/2-outertube/2-dface); dz=0;
The inertia matrix is updated by incorporating contributions from the front torus and the mass of the loop The diagonal elements reflect the sum of the inertia values and the squared distances multiplied by the mass of the loop, while the off-diagonal elements are adjusted by subtracting the products of the distances and the mass of the loop Specifically, the first row accounts for the inertia in the x-direction, the second row for the y-direction, and the third row for the z-direction, ensuring a comprehensive representation of the system's rotational dynamics.
%Left Loop dx=lface/2-outertube/2-dface; dy=0; dz=0;
The calculations for the inertia matrix I involve updating its elements based on contributions from the left torus and the mass of the loop Specifically, I(1,1) is adjusted by adding Ilefttorus(1,1) and the product of the squared differences in y and z multiplied by the mass of the loop For I(1,2) and I(1,3), the values are negated and adjusted by incorporating Ilefttorus(1,2) and Ilefttorus(1,3), respectively, along with the products of differences in x with y and z Similarly, I(2,1) and I(2,3) are updated with negative adjustments, while I(2,2) is increased by Ilefttorus(2,2) and the sum of squared differences in x and z Lastly, I(3,1) and I(3,2) are also negated and modified by their corresponding left torus values and the products of differences in z with x and y.
%Right Loop dx=-(lface/2-outertube/2-dface); dy=0; dz=0;
%Bottom Pump dx=0; dy=-(lface/2-dface-lpump/2); dz=lface/2-dface-hpump/2;
%Top Pump dx=0; dy=lface/2-dface-lpump/2; dz=-(lface/2-dface-hpump/2);
%Left Pump dx=lface/2-dface-hpump/2; dy=0;
The matrix I is updated based on the contributions from the left pump and the pump mass, with specific calculations for each element For the first row, the first element is increased by the left pump's contribution and the product of the pump mass and the sum of squared differences in the y and z directions The second and third elements in the first row are decreased by the left pump's contribution and the product of the pump mass with the respective differences in the x, y, and z dimensions The second row follows a similar pattern, with the first and third elements being decreased while the second element is increased by the contributions from the left pump and the squared differences in the x and z directions The third row sees the first and second elements decreased, while the third element is increased by the left pump's contribution and the sum of squared differences in the x and y directions The final matrix I reflects these comprehensive updates.
%Right Pump dx=-(lface/2-dface-hpump/2); dy=0; dz=lface/2-dface-lpump/2;
The matrix I is updated based on the contributions from the right pump and the pump mass The first row is adjusted by adding the right pump's value and the product of the pump mass with the squared differences in the y and z dimensions for the first element, while the second and third elements are modified by subtracting the right pump's value and the product of the pump mass with the respective dimension products In the second row, the first and third elements are similarly adjusted, while the second element incorporates the right pump's value and the sum of squared differences in the x and z dimensions The third row follows a similar pattern, with the first and second elements being subtracted and the third element being updated with the right pump's value and the sum of squared differences in the x and y dimensions The final matrix I reflects these comprehensive adjustments.
%Front Pump dx=0; dy=-(lface/2-dface-hpump/2); dz=lface/2-dface-lpump/2;
The matrix I is updated by incorporating the contributions from the front pump and the mass of the pump Specifically, the diagonal elements of I are adjusted by adding the corresponding elements from Ifrontpump and the product of the squared differences in dimensions (dy, dz) or (dx, dy) multiplied by the pump mass Conversely, the off-diagonal elements are modified by subtracting the contributions from Ifrontpump and the product of the respective dimensions, ensuring that the overall structure of the matrix reflects the dynamics of the system accurately The final matrix I represents the cumulative effects of the pump's mass and its interactions within the defined spatial parameters.
%Back Pump dx=0; dy=lface/2-dface-hpump/2; dz=-(lface/2-dface-lpump/2);
Trong đoạn mã này, các biến I(1,1), I(1,2), I(1,3), I(2,1), I(2,2), I(2,3), I(3,1), I(3,2) và I(3,3) được cập nhật dựa trên các tính toán liên quan đến Ibackpump và pumpmass Cụ thể, các phần tử của ma trận I được điều chỉnh bằng cách cộng hoặc trừ các giá trị liên quan đến các biến dx, dy và dz, cũng như các giá trị từ Ibackpump Điều này cho thấy sự tương tác giữa các yếu tố khác nhau trong hệ thống, ảnh hưởng đến trạng thái của ma trận I.