Guided Parafoil System
|Snowflake is a similar prototype of an autonomously guided parafoil.|
|Team Name||Guided Parafoil System (GPS)|
|Duration||Fall 2014 - Spring 2015|
This project will develop a system for the successful deployment of a small parafoil from a ‘can’ in space or near-space environments using wireless technologies. The wireless communication, command, and control system will be used to initiate parafoil deployment, and to wirelessly provide critical high altitude, low Reynolds number flow measurements from sensors on the parafoil. The system will be tested as part of the University of Idaho Near Space Engineering (Idaho RISE) high altitude balloon program. Applications of this work will eventually be incorporated into the TechEdSat collaborative nano-satellite project underway between the University of Idaho, San Jose State University, University of California at Riverside, and the NASA Ames Research Center in Mountain View, California.
- 1 Problem Definition
- 2 Specifications
- 3 Design
- 4 Design Failure Mode Effects Analysis
- 5 Project Learning
- 6 Team Members
- 7 Final Deliverables
- 8 Document Archive
NASA wants to develop an inexpensive on-demand capability to return samples from the International Space Station (ISS). The Small Payload Quick Return (SPQR) system is being developed by NASA Ames Research Center. The SPQR concept relies on a 3-stage method of returning payloads, after being stored until need and loaded on-board the ISS Deorbit, by means of a unique drag system called an Exo-Brake to de-orbit a small spacecraft payload using atmospheric drag instead of rocket thrusters to reduce speed for atmospheric re-entry. The three stages are:
- Stage 1: Erection of the Exo-Brake and descent from 350 to 100 km.
- Stage 2: Deployment of the Tube Deployed Re-entry System (TDRV) from 100 km to 10 km.
- Stage 3: Deployment of the autonomous, GPS guided parafoil from 10 km to ground/retrieval.
Team GPS is interested only with Stage 3.
- Design, build, and test a canister with a deployment system for a small parafoil
- Design a system that reliably inflates and provides rigidity to parafoil ‘gores’ at high altitude
- Select a winch with optimum locking capacity
- Develop a wireless system to transmit commands to open canister and deploy parafoil.
- Use Xbee Series 2 radio module to wirelessly collect data from and transmit via the Iridium satellite network down to the ground.
- Replace altitude switch with a smaller pressure switch.
- Develop a Graphical User Interface (GUI) to present the diagnostic data downlinked from the capsule and to uplink commands to the capsule
- Assist Electrical Engineers in embedded system programming
- Adapt/modify algorithms to guide capsule to the target location
The tables below contain the specification matrices for the ME, EE and CS groups.
Note: 1 = highest priority, 2 = lowest priority
|Table 1: ME Specifications Matrix|
|Major Requirements||Description||Acceptable Value||Ideal Value||Priority Level|
|Parafoil Deployment||Capsule||Parafoil should be fitted with wireless sensors, fit inside upper chamber of PCTCU capsule, deployed in a controlled, reliable manner||Proper inflation of parafoil||Capsule has fail-safe system to release parafoil: main deployment system with backup system||1|
|Parafoil Inflation/Flight||Canopy||Parafoil should be fitted with wireless sensors, fit inside upper chamber of PCTCU capsule, deployed in a controlled, reliable manner||Proper inflation of parafoil||Controlled inflation of parafoil||1|
|Shroud Lines||The shroud lines should not get tangled, especially when descending into the lower, denser atmosphere||Prevent lines from being tangled||Elimination of any tangling and tumbling once deployed||1|
|Winches||Servos||Select a winch that can withstand a high value of torque, in order to control and keep the lock, which prevents the release of the parafoil||Digital, dimensions range: LxWxH : 40.6±5mmx20.1±2mmx38.9±3mm, rotational speed angle not less than 1000°, largest torque, Voltage: 4.8V-7.2V||Digital, dimensions range: LxWxH : 40.6mm x 20.1mm x 38.9mm, rotational speed angle not less than 1000°, largest torque,Voltage: 6V-7.2V, titanium gear metal, speed no less than 0.12 sec/60°||2|
|Table 2: EE Specifications Matrix|
|Major Requirements||Description||Acceptable Value||Ideal Value||Priority Level|
|Microcontroller||Select/Shrink a microcontroller to fit inside PCTCU capsule with enough ports to support various sensors and consumes manageable amount of power||Must fit within a cylinder of radius 7.5 cm and height 6 cm, supports PWM to interface with winches, consumes an appropriate amount of power, have at least 10 I/O ports to communicate with subcomponents||As small as possible to account for insulation, reliable PWM for winch interface, consumes minimal power, have additional I/O ports for future use||1|
|Pressure Switch||Will replace Altitude switch as mechanism to power on board and deploy parafoil. Should be smaller and more reliable than altitude switch||Must fit within a cylinder of radius 7.5 cm and height 6 cm, have the ability to power the board autonomously||As small as possible to account for insulation, low power consumption, testable in vacuum chamber (contingent on university resources), powers on sensors autonomously at desired altitude||1|
|Wireless Sensor Technology||Various sensors will be used to collect data to be stored on SD card and sent wirelessly via Iridium||Provides basic telemetry to demonstrate proof of concept. Include pressure and temperature sensors.||Provides a variety of telemetric data accurately and reliably under extreme climate conditions. Include accelerometer and pressure and temperature sensors.||1|
|GPS||Used for tracking payload and recording mission trajectory||Must have range of a few miles, operates under extreme climate conditions, able to overcome CoCom limits||Long range, reliable and accurate under extreme climate conditions||2|
|Table 3: CS Specifications Matrix|
|Major Requirements||Description||Acceptable Value||Ideal Value||Priority Level|
|GUI||Design and Implement a Graphical User Interface for data retrieval on a variety of platforms.||Mobile device compatibility (Android), basic retrieval of data, and an attractive, usable interface.||Multiplatform compatibility, ability to receive data and send commands, and a streamlined interface using proven GUI design principles.||1|
|Flight Algorithm||Implement a control algorithm to autonomously guide the parafoil to its predetermined destination.||Implementation and refactoring of,existing algorithms to achieve task.||Optimization of existing algorithm, through use of secure coding principles and additional research.||2|
|Xbee Networking||Research and implement a network addressing scheme.||Static allocation, hardcoded addressing of network capable components.||Dynamic addressing of devices, hierarchical subnets, and network topology diagram.||2|
|Data Visualization||Graph representation of data points for analysis and presentation.||Key data represented as graphs, presented statically for reports and documentation.||Dynamic presentation of data, integrated with GUI.||1|
Figure 3 illustrates the Mechanical Engineering Hardware for the system. The three systems are the parafoil, the Payload Containment and Thermal Control Unit (PCTCU), and the control system as illustrated in figure 4. The parafoil will be re-designed with the consideration of stiffness, inflation, and sensors. The two types of sensors used for the parafoil are temperature sensors and pressure sensors. The success of the parafoil after deployment is determinant on the inflation system and the rigidity of the parafoil itself. The PCTCU will be used as our canister that will contain our packaged parafoil and the control system. The PCTCU diameter is 13.81 cm, and a height of 17.4 cm.
When selecting the servo, the aspects of servo torque, size, mass, operative voltage, gear metal type, and transit speed were used to determine the required servo. Commercially available servos were compared as illustrated in table 4. The best winch servo is Vigor VSD-22YMB where it can deliver the most torque while maintaining six cycles of rotation.
- Uses easily attainable CO2 Cartridges
- Uses minimal moving parts
- Proven field use:
- Similar systems used on high-altitude balloons, amateur rocketry, and UAV’s
- Peregrine IDS
- Sentinel CO2 Deployment System
- Rouse-tech CD3
Figure 5 to the right depicts of the electrical hardware side of the system. Many aspects of this system are re-used from both VAST and NASA. Data collected from the wireless sensors is packaged and transmitted to the ground via the Iridium Satellite Network. In addition when the Xbee Series 2 radio module is within range of the ground station it wirelessly transmits data without having to go through Iridium.
A new pressure switch system will be built. The purpose of the system is to allow the XBee sensors to turn on at a certain altitude in order to conserve power throughout flight. When the balloon reaches an altitude of 50,000 feet the board will turn on. Three pressure sensors are used for the sake of redundancy.
Figure 6 is the proposed set-up for connecting the Mega Pro with Iridium and the XBee radio modules. This system was initially designed by Gabriel Pearhill during a internship at NASA Ames. The Mega Pro board was selected due to the high number of Digital and Analog I/O pins that the board contains. The current set-up includes a system that is currently compatible for the Iridium 9602 modem. The team is also considering implementing the Iridium 9603 modem. Both are very similar in specifications with the major difference being size and the size of the pin connectors. However, this set-up should still be compatible with the Mega Pro and only minor changes will be needed.
Each XBee radio module has pressure and temperature sensors. These sensors will be placed in strategic locations on the capsule and if possible, on the parafoil itself. The gyroscope will be located in the capsule itself.
XBee Radio Modules
There are currently two types of XBee modules which are Series 1 and Series 2. In addition, both series have a standard and a PRO version that adds more functionality to the radio module. These radio modules are used to wirelessly transmit data between radio modules.
XBee Series 1 uses the 802.15.4 standard and can be set up in such configurations as Single Peer, Multi-Peer and Broadcast. Series 2 uses ZigBee, which is a specification for a suite of high-level communication protocols used to create personal area networks built from small, low-power digital radios. ZigBee is based on an IEEE 802.15 standard. Though its low power consumption limits transmission distances to 10-100 meters line-of-sight, depending on power output and environmental characteristics, ZigBee devices can transmit data over long distances by passing data through a mesh network of intermediate devices to enhance its effective range. ZigBee has a defined rate of 250 kbit/s, best suited for intermittent data transmissions from a sensor or input device.
For our project we have decided to work with XBee Series 2 due to the functionality of ZigBee protocol and the flexibility that it will have for future NASA projects.
Table 5 below shows a quick comparison between various flavors of XBee radio modules.
|Series 1||S1 PRO||Series 2||S2 PRO|
|Transmit Receive Current||45/50 mA||40/40 mA||40/40 mA||295/45 mA|
|Power Output||1 mW||60 mW||2 mW||63 mW|
|Outdoor Range||100 m||1500 m||120 m||3200 m|
|Size||2.438 cm x 2.761 cm||2.438 cm x 3.294 cm||2.438 cm x 2.761 cm||2.438 cm x 3.294 cm|
For the project a PCB was designed to the pcb104 standards (89.4 mm x 95.0 mm). The PCB houses a Teensy 3.1 microcontroller, digital pressure/temperature sensors, IMU, XBee series 2 radio module, Arduino GPS breakout board, micro SD card mount, Iridium 9603 modem and voltage regulators for powering the board and its components. The board was designed with free software called Diptrace and fabricated by Advanced PCB.
Our current software design has several components:
- Email parser - Prepares information by tokenizing data fields received via email messages.
- Data table - Structure which stores parsed data for easy retrieval.
- GUI - Flat, clean, non-convoluted design, implemented in HTML5 for platform compatibility.
The Iridium modem used in our design only supports email communication. Emails with a specific data format will be sent from Iridium to the specified Gmail inbox, either upon request or regular intervals. The specific data payload is yet to be determined, and will be based on further analysis of sensor data requirements. The Email Parser will scan and tokenize data retrieved using the Gmail API, and then store the formatted data into the Data Table. The GUI will be implemented to retrieve from the Data Table, depending on desired output requirements.
Design Failure Mode Effects Analysis
This table represent our current DFMEA model.
|Description of component, subsystem, or function.||Symptom||Effect||Failure Mode||Probability of Failure(Low: 1High: 5)||Severity of Effect(Low: 1High: 4)||Risk Priority|
|Deployment System||Parafoil did not completely deploy||Uninhibited Descent||CO2 Canister was not punctured||3||4||12|
|Insufficient CO2 pressure to deploy parafoil||3||4||12|
|Springs didn't elongate enough||3||4||12|
|Inflation System||Parafoil is tangled||Rapid Descent, No Steering||Lines tangled||3||4||12|
|Fiberglass rods are broken||3||4||12|
|Controls||Little/No Steering||System does not land in target area||Winches are broken||2||2||4|
- The Iridium 9603 data modems have a mechanical failure during vibration tests, so we should look into other modems to use for Iridium communication.
- We have an Iridium 9602 modem. The Iridium 9603 is too small to survive the vibration tests when connected to the board, but it is smaller and more efficient than the Iridium 9602. We will likely look into remedying this mechanical failure if we decide to use a similar Iridium modem for the final product.
- Techniques for deploying, and inflating the parafoil.
- These techniques will probably include a method for stiffening the parafoil.
- We will have to run tests on our deployment and inflation system in low pressure atmospheric conditions, so finding a vacuum test chamber will be imperative.
- Vacuum test chamber must be large enough to house the parafoil and its capsule.
- Miniaturization of the system.
- By incorporating the sensor boards with the microcontroller.
- Snowflake currently uses a diaphragm based altitude switch, but we want to use a pressure switch instead to reduce the required size for the electronic subsystems.
- We will need to find a vacuum test chamber to calibrate the pressure sensors (probably the same chamber we will be using for the parafoil tests).
- Eventually we will want to shift from XBee-Series 1 to XBee-Series 2 sensors to increase the distance that the sensors can be placed from each other.
- The current system is based on XBee series 1 chip. We want to switch to the Series 2 chips which utilize a ZigBee network for communication.
- How accurate of a pressure measurement is required to replace the altitude switch.
- Language preferences: Java vs Python for graphics.
- Look into using Gmail Application Programming Interface (API).
- For parsing diagnostic data downlinked from the capsule.
- For creating commands to send to the capsule.
|Brandon Arakawa||Electrical Engineering|
Brandon is a senior in Electrical Engineering at the U of I. His primary areas of interest are electromagnetics and control systems. His internship experiences include malware programming for the Center for Cyber Warfare at the Naval Postgraduate School in Monterey, and simulation verification for the DRAM product engineering team at Micron Technology. In his free time he enjoys playing the piano, chess, or any kind of board game with friends. After graduation, Brandon intends to pursue graduate school and explore both M.S. and Ph.D. as options.
|Jason Bjur||Electrical Engineering|
Jason is a senior in Electrical Engineering with an emphasis in electromagnetic analysis and antenna design as well as analog design. He will graduating in May of 2015. He has had three internships with with GE Aviation working on products such as actuators, avionics, and developmental jet engine testing. He is planning on pursuing a full time job in the aerospace industry upon graduation.
|Ben Cumber||Computer Science|
Ben is a senior in Computer Science and will be graduating in May 2015. Last summer, he worked as a research assistant in the Center for Secure and Dependable Systems at the University of Idaho. Ben is a member of Scholarship for Service--a program started by the US Government to strengthen the US Cyber Security workforce. Ben will pursue a career in that workforce upon graduation.
|Brian Kisling||Mechanical Engineering|
Brian grew up in Pocatello, Idaho and is currently a senior mechanical engineering student at Univeristy of Idaho. He has interned at the University of Idaho analyzing a Reactor Cavity Cooling System or RCCS using CFD software. Brian's interests include fluid and thermal systems, and plans to attend graduate school after graduation in Spring 2015.
|Richard Park||Computer Science|
Richard is a senior in Computer Science, and will be graduating Spring of 2015 with a B.S.C.S. He has worked as a research assistant for the Center for Secure and Dependable Systems since Spring 2014. He is experienced in information and network security, data modeling, and GUI development.
E. is senior in the Mechanical Engineering department with an emphasis in Robotics,and will be graduating in May of 2015. She is involved in campus activities such as ASME, SWE, and AeroSpace Club. E. has had internships with both STRATA and Boeing. She plans to pursue a masters in Robotics, having had previous Robotics experience as both competitor and judge in NASA's FIRST Robotics competition. She is in the process of obtaining her first patent, which focuses on artificial intelligence containing a robotic device that assists humans.
|Forest Austin Tanner||Mechanical Engineering|
Austin is a senior Mechanical Engineering student at the University of Idaho planning to graduate in May 2015. His greatest areas of interest are Aeronautics and Astronautics. He has always had a love for flying and received his Private Pilot’s license in 2009 at the age of 17. Currently, he is the Flight Director for the University of Idaho’s Near Space Engineering class, a project-based class in which students launch high-altitude weather balloons with science and technology payloads to altitudes approaching 100,000 ft. His future plans include pursuing a career in the aerospace or space industry.
|Steve Wayne||Electrical Engineering|
Steve is a senior at the University of Idaho studying electrical engineering with a focus in either applied electromagnetics or robotics. He has interned for both Schweitzer Engineering Laboratories, and NASA's Jet Propulsion Laboratory. He is planning on attending graduate school for electrical engineering upon graduation.