Terrestrial Aircraft for Reconnaissance Applications (Project TARA)

Transcription

1 Terrestrial Aircraft for Reconnaissance Applications (Project TARA) B. S. Electrical and Electronics Engineering and Optical Engineering Norfolk State University 2016 Project Mentor Dr. Demetris Geddis Dr. Patricia Mead Submitted by: James Daniels Ashley Deal Robert Floyd Nsilo Greene John P. Harris Jazlyn Jones Tristan Skinner Kelsea Yarbrough NORFOLK STATE UNIVERSITY TEAM T.A.R.A 1

2 Contents Abstract...3 Description of System Engineering...3 Description of the UAS design...7 Results and Discussion Safety considerations/ approach NORFOLK STATE UNIVERSITY TEAM T.A.R.A 2

3 Abstract The aim of the project is to design an Unmanned Aerial Vehicle (UAV) with the capacities to identify electro-optic (EO) targets. The UAV used in this project is a VTOL (vertical takeoff and landing) aircraft. This aircraft model was chosen because it has the ability to take off in a mode similar to that of a helicopter with the added capability to fly like a fixed wing aircraft. With these attributes, the UAV chosen is very unique and flexible. It also offered the ability to make modifications that were necessary for this project. Some primary goals of the project include operating the UAV autonomously with the capability to travel to precise locations on Earth using a Global Positioning System (GPS) and an autopilot system, installing two cameras (one for first person view and the other for target recognition), and incorporating an inertial measurement unit (IMU). For safety purposes, the UAV was designed to weigh less than 55 pounds and programmed with a fail-safe mode. Multiple power system configurations have been designed and bench-tested using 3s (11.1 Vdc) and 6s (22.2 Vdc) batteries. A lens system has been designed to increase the magnification of images from the optical system to capture images from 75ft to 100 ft. A 915 MHz RF communication link between the UAV and ground monitoring station and mission control software has been installed and configured. 2. Description of System Engineering 2.1 Mission Requirements Analysis of Planned Tasks Autonomous Flight Task Parameter Threshold Objective Takeoff Achieve controlled takeoff. Properly transition to autonomous flight Achieve controlled autonomous takeoff. Properly transition to Flight Wavepoint Navigation Maximum of 3 minutes manual flight. Maximum of 3 manual takeovers from autonomous flight. Capture waypoint in sequence with ±50 ft. accuracy, and maintain navigation ±100 ft. along the planned flight path autonomous flight. Achieve controlled autonomous flight with no manual flight, except for transition from manual takeoff. Capture waypoint in sequence while in autopilot control with ±50 ft. accuracy, and maintain navigation ±100 ft. along the planned flight path. NORFOLK STATE UNIVERSITY TEAM T.A.R.A 3

4 GCS display items Landing Search Area Task Accurately display no flyzone boundaries and shall accurately display current aircraft position with respect to the no flyzone boundary, display indicated airspeed (KIAS) and altitude (feet MSL) to the operators and judges. Achieve controlled landing. Properly transition from autonomous flight. Parameter Threshold Objective Localization (each standard and QRC target) Determine target location within 150 ft. Must be paired with at least a threshold classification. Specific requirements listed in Section Achieve controlled landing. Properly transition from autonomous flight. Determine target location within 75 ft. Must be paired with at least a threshold classification. Classification (each standard target) Provide any two target characteristics, electronically. Provide all five target characteristics, electronically. Classification (QRC target) Detection. Decode the message. Imagery (each target) n/a Provide cropped target image (>25% of image frame). Autonomous Search n/a Aircraft in autopilot control during search. Secret message n/a Decipher the message anagram collected from the targets in the search area. ADLC Task Parameter Threshold Objective Automatic Localization (each target, standard and QRC) n/a Automatic Localization (each target, standard and QRC) Automatic Classification (each QRC target) Automatic Classification (each QRC target) Actionable Intelligence Task n/a Automatically tag and identify target position within 150 ft. Provide at least three of five target characteristics electronically. n/a Automatically decode the message. n/a Demonstrate > 50% (with only 6 detections >50% is a 67% classification rate). NORFOLK STATE UNIVERSITY TEAM T.A.R.A 4

5 Parameter Threshold Objective Actionable Intelligence (any target) Provide target location within 150 ft. and 3 characteristics electronically, while airborne during the same flight. Provide target location within 75 ft. and all 5 characteristics electronically, while airborne during the same flight.- Interoperability Task 2.2 Design Rationale Firefly 6 is a VTOL system it gives us the ability of both a plane during flight and a helicopter during takeoff, which can be very helpful and unique but also a daunting task to handle at times. There were two pilots used for this plane. The reason two were used was for a pilot and copilot just in case anything goes wrong in autonomous mode they can take over and fly the plane. Both had to get their AMA licenses which had insurance that covers up to $20,000. With many modifications made to the airframe it has become a work of art. The Firefly 6 has six motors that have to be powered for flight so this craft takes a lot of power to fly, so multiple power system configurations have been implemented so that there are choices as to how we will fly the plane. Also for identifying optical targets lens systems were implemented so that the camera used could magnify the objects that are being targeted. 2.3 Expected task performance Team composition Below is a diagram of our plan of implementation. Each section is labeled with no more than two group members. The leader of the UAV project is Nsilo. Followed by the two pilots Kelsea and Tristan. For this project we wanted to have at least two pilots in case one pilot would not be available when we would be flight testing. Next we have to group leaders, one for the hardware team (Tristan) and one for the software team (John). Our safety team is followed by Ashley, she will handle all the safety requirements for us to fly our UAV, as well as creating a safety checklist. The maintenance team is James and Nsilo. Next is the Power system where Ashley and Nsilo will conjure up a plan that will insure we are servicing enough power for each of our components in our system and to increase flight time. Our next group is the Imaging system and Imaging algorithm where these group will control the GoPro (camera) and several other imaging components for the UAV system and increase the magnification of the GoPro. Lastly will be the Navigation system and Navigation Algorithm where these members are NORFOLK STATE UNIVERSITY TEAM T.A.R.A 5

6 responsible for the Global Positioning System, Inertial Measurement Unit, Radar, and the Autopilot system. The purpose of Project Tara is to design an UAV with the capacities to identify electro-optic (EO) and Infrared (IR) targets and precise locations on Earth. UAV is an acronym for Unmanned Aerial Vehicle, which is an aircraft with no pilot on board. UAVs are in high demand in not only military use but commercial everyday use. That is why Project Tara s goal is to create an innovative an UAV. This was achieved by designing and hand constructing the aircraft by applying background knowledge of electrical and optical engineering. Though there are were a few expected problems with proper design, planning, and testing they did not affect the overall project. After completing the creation of Project Tara UAV there are hopes to implement it everyday use. Our initial plan was design an Unmanned Aerial Vehicle (UAV) with the capacities to identify electro-optic (EO) and Infrared (IR) \ targets and precise locations on Earth. However, we were unable to complete this task as the semester wined down. But we are still working on it and will have it done by competition time. Next we programmed a control system that allows the UAV to operate in autonomous and remote/ manual modes. Also we incorporated systems such as a Global Positioning System (GPS), autopilot system, a camera imaging system, inertial measurement unit (IMU) and a communication link between the UAV, remote control and a surface laptop. Finally, we incorporated a fail-safe mode system. Gathering information and advice for every model considered the firefly six was chosen as the best opinion. The FireFLY6 is a VTOL aircraft. A VTOL aircraft (vertical take-off and landing), is a type of aircraft (like a plane) that can take off vertically, then fly horizontally. The advantages of VTOL planes are that they can take off in small spaces just like a quadcopter, but also fly longer and faster like a plane. The FireFLY6 is technically an Y6 configuration. The two motors in the back of the plane are only for hovering and remain off during forward flight. The other four motors in the front of the plane also allow it to hover, with the exception that in NORFOLK STATE UNIVERSITY TEAM T.A.R.A 6

7 forward flight mode, the motors rotate 90 degrees to produce forward thrust. Because the FireFLY6 is a plane, it has a relatively high flight time from 20 to over 30 minutes depending on your setup. In hover mode it gets 7 minutes of flight time. 3. Description of the UAS design 3.1 Design Manual flight control is provided through a 2.4 GHz 9 channel RC radio link. The flight controls are passed into a Pixhawk 4 autopilot system which provides the system with autonomous flight capabilities which include: Take off; landing; and waypoint navigation, with the ability to make in-flight adjustments.the Pixhawk also provides sensor data and control data to the payload subsystem. T he Pixhawk is configured with a barometric altimeter, GPS, magnetometer, dual inertial measure ment units (IMU), differential pressure airspeed sensor, safety buzzer, and safety switch. The dual IMUs provide redundant measurements. The barometric altimeter provides the autopilots altitude above ground level. The GPS provides 3D position. The compass/magnetometer provides heading, and the differential pressure sensor provides airspeed. The System Block Diagram of Project TARA 1) The Power Distribution System requires 22.2 Vdc to launch the UAV. The original power system of the Firefly 6 is design with two 3s (11.1Vdc) in series. This system does not allow for any redundancy. Once the batteries are drained to 20 Vdc (10Vdc per battery) the UAV has to be landed and the batteries have to be changed. This is any average fly time of 20 minutes (70 minutes when doing bench testing). NORFOLK STATE UNIVERSITY TEAM T.A.R.A 7

8 Our design will be used to increase the flight time and create redundancy. This will be achieved by taking two 6s (22.2Vdc) batteries and putting them in parallel. This should double the flight time minus the increase in weight. Each component added required a separate battery, but the same voltages 5 Vdc or 11.1 Vdc respectfully. These different batteries add weight to the UAV and requires upkeep. Our design will add two battery eliminating circuits (BEC) to the power distribution board. The extra components will be added to them and all required volts will be distributed from the power distribution board. The increase in voltage pull from the Power Distribution Board will decrease flight time, but the decrease in weight of the extra batteries will balance it back to almost twice the flight time we are trying to achieve. Figure 4: Block Diagram of the Power Distribution System 1) To incorporate varies components like the GPS, autopilot, IMU, communication links and camera images, the software compatible to the Pixhawk has to be installed and proven to work. The Pixhawk 4 is the brain to the UAV and all components need to be able to communicate with it. So software like Mission Planner, links and raspberry pie have to be installed and test. NORFOLK STATE UNIVERSITY TEAM T.A.R.A 8

9 Figure 5: The FireFly 6 Mission Planner Software The main goal of the software team is to make sure all of the programs are running efficiently and smoothly for the UAV tests and later for the evaluation during the competition. The software has a few goals for the specific UAV that is being used for this project. Overall, the software must be compatible with the FireFly 6 and all of the components including: Pixhawk PX 4 flight controller, 3DR power module, 3DR GPS/Compass units, and flight motors and electric speed controllers (ESCs), and any other peripheral devices. The program(s) must be able to not only be able to allow for full control of the UAV but also allow for full functionality to the Taranis Radio Controller. Another program is also used to collect control data from flight controller and place all positioning data unto a data server that will be used for judging purposes during the competition (also called an interoperability server). These two components (the flight controller and competition server) must be able to operate simultaneously and consistently during flight. To ensure the software is the best fit for this project 5 checks were completed and graded. These checks included: 1. Compatibility: This check is to ensure that all software downloaded is compatible with the entire Unmanned Aerial System (UAS) which includes the aircraft, laptop, server, RC Controller, and all external peripheral components. 2. Calibration: Not only does the software need to be able to control components, but also needs to be able to directly measure values and control them, so that all components are working at the same rates and values. 3. Detection: The flight software must be able to detect aircraft position with the GPS/compass and then show a detailed map that shows all hazards including highways, airports, powerlines, and railways. 4. Safety: Along with the flight detection the flight software must be able to avoid hazards automatically. This includes any preflight calibration and checks, and fail safes should also be implemented to avoid any inflight problems. NORFOLK STATE UNIVERSITY TEAM T.A.R.A 9

10 5. Accuracy: This is one of the most important components for the competition. All programs installed should not only be able to control the aircraft to reach certain GPS locations, but also must do so as accurately as possible in order to gain as many points as possible (and to increase safety) 2) The camera images need to be sharp and identifiable, but the best camera for the project (the GoPro) does not have the ability to zoom in and out and does not cover the required distance of 75 to 100 ft. So our design will also incorporate a lens system that will meet the requirements. This system needs to be able to communicate with the Pixhawk and the ground station. Also our design needs to be lightweight so that our overall design will remain under eight pounds. Figure 6: The design of the optical system 3.3 Picture of the UAS 4. Results and Discussion Issues that delayed our progress Using one 3s battery is not enough to power the UAV, with the high efficiency motors we are using. These motors need 22 vdc to get off the ground. The only solution is the put two NORFOLK STATE UNIVERSITY TEAM T.A.R.A 10

11 3s batteries in series or one 6s battery with.4 pounds extra added to the opposite wing to achieve balance. Figure 7: The schematic of two 3s batteries in series. The initial pixhawk 4 was programmed, but 5 out of 6 electronic speed control (esc) would communicate with it. The landing gear and the transition servo also did not communicate with the pixhawk 4. The afternoon of Friday, February 26, 2016 while replacing the nonworking esc the firefly 6 caught on fire. The fire was put out but the main body was damaged. The pixhawk 4, battery eliminating circuit (BEC), global position system (GPS) was replaced Saturday after the rebuild. The power distribution board, 6 motors, 2 esc, all components on both wings and the transition servo has been savaged. After rebuilding the UAV Saturday February 27, 2016, The RC controller will not arm, so no bench checks were completed. The transition servo and the elevons shifted when the pixhawk 4 was arm. The new esc need to be soldiered to the motors and the landing gear needs to be tested. It was discovered that the 3s batteries cannot be drained below 10vdc. Once this happens they must be safely disposed. These batteries will not charge to capacity. Once they are charged over nine Vdc the cell will explode. This happen to one of the 3s batteries we use to power the UAV. NORFOLK STATE UNIVERSITY TEAM T.A.R.A 11

12 Trying to hoover in 20 knot winds. Also trying to hoover in the football field with the swirling winds. The wind will make it hard to control the UAV because it is so light. In theory the Pixhawk 4 will stabilize the UAV and this should not be an issue. This does not apply in manual mode. Plus the football stadium is round and the wind swirls and push up which will affect the control of the UAV. When we attempted to fly Project TARA in the football stadium this issue became a big issue. The wind pushed the UAV onto the Tide tracks. The back motors were damage and the wings were destroyed. Improvements Since first getting our UAV off of the ground we have made numerous amounts of improvements. To prevent the battery from draining as soon as it is placed in the UAV and to allow adjustments and repairs without always removing the batteries a power switch has been installed. This switch allows us to secure power to the UAV. Increasing flight time is any important aspect to this project. So to gain more flight time the power distribution system was improved to allow two 6s batteries to operate in parallel. This almost doubted the flight time, but adds about.8 lbs. to the UAV. The.8lbs is the reason the UAV flight time did not completely doubt even though the batteries in parallel decrease the current draw on the batteries by half. Figure 27: A schematic diagram of two 6s batteries in parallel. NORFOLK STATE UNIVERSITY TEAM T.A.R.A 12

13 Voltage and Current (volts and amps) Two 3s 20c 4000mah Batteries in Series Time (min) Figure 28: A chart of the drainage time of two 3s batteries in series. 30 Two 6s 30c 3600 mah 2 Batteries in Parallel Voltage and Current (volts and amps) Time (min) Figure 29: A chart of the drainage time of two 6s batteries in parallel. NORFOLK STATE UNIVERSITY TEAM T.A.R.A 13

14 After our first crash with the UAV the body of the craft suffered some pretty bad damage. Due to that, we had to repair the back end of the plane where the back motor is located, with gorilla glue and duct tape. With this repair the motor was able to remain in place during future flight tests. We also made safety improvements due to one of our 22 V batteries exploding. The improvements were made by placing all fully charged batteries and batteries not being used into a cinderblock with a stone cover incase another battery does the same as the first battery. We also acquired an ammo box and a battery insulator bag to protect and carrier the batteries from one location to the next. The legs on our plane suffered some damage due to a few landing incidents during each of our flight tests, so to improve the legs, we drew up a design for new legs and had them 3D printed to be attached to our craft in place of the old Legs. To avoid using an extra battery in the plane to power up both transmitters for each camera, we programmed a battery eliminating circuit (BEC) to give off 12 V to power up both the Go Pro hero 4 and the digital video camera (FPV), also avoiding the extra weight on the plane from another battery. When looking through our cameras from the ground station, once an object get further away it becomes harder to see. A way we are improving that is by building a lens system to magnify the image that we are seeing with a negative lens in front then following a positive lens. Final Results In order for the aircraft to be controlled effectively software must be implemented. These programs are used for automation and helps to make all components synchronous. There were three flight manager programs that were checked for compatibility with the FireFly6. These programs include the following: 1. QGroundControl: This is a software created by the developers of the Pixhawk PX 4 flight controller. This program is free, but is not editable. It is highly recommended, and obviously is compatible with the flight controller used in this project. 2. Mission Planner: This is a software created by the developers at ArduPilot, a very popular aircraft and rover open source platform created by DIY Drones community. This software is much more user friendly and is completely open source and free to edit. 3. FireFly6 Planner (also known as AvA Planner): This is software is an edited version of Mission Planner that is made to be compatible with the FireFly 6, and was created by the developers at BirdsEyeView. This software is not completely open source, but many changes can be made. All three of these programs were checked for compatibility for the complete UAS; however, due to some errors in compatibility with QGroundControl only Mission Planner and FireFly6 Planner were continuously checked. NORFOLK STATE UNIVERSITY TEAM T.A.R.A 14

15 The first part of the software that was evaluated was compatibility. To check this part of the software the correct firmware was placed onto the Pixhawk PX4 flight controller. For mission planner, the most compatible firmware was found online, and configured due to the FireFly 6 vertical takeoff and landing features. Though the software worked effectively with the Pixhawk and all components, when the aircraft was placed into copter mode it s shaped changed on the screen, which could be distracting. Mission planner was given a 90 percent in compatibility due to this fact. FireFly 6 Planner was then tested for the same parameter. The most up to date firmware was place on the Pixhawk that was compatible with the software, and all of the components were tested in terms of control. All components worked effectively; in addition, there was no change of the aircraft during transition from plane to copter modes. This software received a 100 percent rating for this reason. The second component of the software that was tested was calibration. For the check all of the ESCs (electric speed controllers), accelerometer, and compass were calibrated to see if the calibration would successfully complete and allow for smooth flight. To calibrate the ESCs the firmware was temporarily stopped, and a soft reset was placed on the Pixhawk board. This allows for all of the speed controllers for the motors to be calibrated to maintain the same output voltage. This was successful for both Mission Planner and FireFly 6 Planner firmware. Both Mission Planner and FireFly 6 Planner contain a calibration component in their software, which allows for more control of special components like the accelerometer and the compass. Both of these programs received a 100 percent in the category of calibration for this reason. The next parameters that were tested in the software were detection and safety. Test check the detection part of the software both programs were started with a GPS lock. This allows for the software to hone in on the exact location of the aircraft. Then on the flight data screen the location of the aircraft was shown on a map. Both maps were powered by Google and seemed to be a very accurate reading of the aircrafts location. Then, the map was explored to see what hazards can be found near that location. Both versions of Mission Planner allow for the viewer to see detailed versions of streets, highways, and railroads. Most importantly, the maps showed automatic avoiding areas like airports and military bases. These areas have automatic failsafe modes that occur when the aircraft reaches these points, the usual response is to return to launch or automatic land when these points are reached. These modes can be set by FireFly 6 Planner and Mission Planner in order to set what should occur during any failing hardware (like radio controller loss, GPS loss, or high magnetometer). For both of these programs the software helps to ensure safety during flight, and thus both received another 100 percent in terms of safety. The final component of the software that needs to be tested is accuracy. Just as previously stated, accuracy is one of the major components of the competition. The judges will tabulate our final points based on how close we come to the general location that we have set. To ensure that the software is performing at peak accuracy two test were completed. The first test was to see how large of an area would a GPS error would result in. After some testes it concluded that with a bad GPS location a radius of 200+ yards could be displaced. However, when the GPS is at an optimal setting the location will only differ by a couple of feet, perfect for competition setting. The second test was just comparing the reading of the altimeter to the actual height of the plane. To test this test however, flight test must be done very precisely, and consequently the aircraft is not able to achieve this goal yet. For now, the results of accuracy test are inconclusive. However, NORFOLK STATE UNIVERSITY TEAM T.A.R.A 15

16 enough information was gathered from previous tests to see that FireFly 6 Planner is the best program to use. When testing QGroundControl for compatibility the recommended firmware was downloaded onto the Pixhawk PX4 flight controller. Upon completion and proper restart, the controller blinked RED and played a loud beeping tone. After checking the Pixhawk manual it was realized that this light and beep were from a firmware error on the chip. Once the firmware was reset the noise stopped and Pixhawk began to operate again. This kept happening no matter which QGroundControl software was put uploaded to the chip. This was thought to be because of the type of plane used for this project; the FireFly 6 is a vertical takeoff and landing (VTOL) aircraft meaning that it is a hybrid between a copter and a fixed wing plane. This PX4 could be recognizing the aircraft as a VTOL and the firmware uploaded could only upload either a copter firmware or a fixed wing plane firmware (and trigger the switch between both). However, this does not seem probable due to ability of the flight controller: it does not realize the aircraft type until firmware is uploaded. So, the next hypothesis is that even though QGroundControl was the second software recommended by the Pixhawk creators, it might not be completely compatible with the PX4 flight controller. Safety considerations/ approach 5.1 Flight Safety Criteria Safety is an important factor in the development and operation of autonomous systems. Safety begins at the preflight brief when the team s Safety person reviews the safety protocols and rem inds the team of the risk, especially those specific to each mission. During the mission, individual checklists help to ensure every team member conducts their jobs safely. The checklist specificall y check to ensure each member meets all of their assigned safetygoals. The Safety goalare specif ic points on the checklist which must be passed. At these points the team member reviews all th e safety points they have passed, and reports these to the team lead and Safety person. These Safety goals help to ensure team communication and safe operatio aft er the mission, team member meet to discuss lessons learned in the systems, navigation, area, navigation, sensors(s.c.a.n.s) format. An excerpt from the pre flight checklist is presented below. 5. PRE FLIGHT CHECKLIST This checklist is to be completed immediately before each flight to ensure the safety of both the aircraft and any personnel. Prep Plane: 1. Ensure the ESC is not connected to the power module 2. Connect flight batteries to UAS 3. Turn on power switches wait for Autopilot to start up 4. Verify autopilot boot a. Main LED = Blue or Green b. One long tone NORFOLK STATE UNIVERSITY TEAM T.A.R.A 16

17 5. Turn on camera 6. Turn on controller 7. Visually verify DataLink connection via status LEDs 8. When prepared for take-off, check motors to see if functioning fully 9.SAFETY QUALITY GATE: Report to SO and MC a. Batteries connected securely b. Autopilot boot successful c. Payload boot d. Datalink Boot e. ESC startup 5.2 Risk Mitigation The team has taken a number of steps in order to reduce the risks to both bystanders and the UAS. The most fundamental safety precaution taken was the inclusion of a safety person on the team. The Safety person is required to maintain constant view while on the flight line to ensure every team member conducts their jobs safely. The team has implemented failsafes to en sure that the UAS complies with section of the AUVSI SUAS rules. The team requires that all pilots be AMA licensed. All flights are logged and failures are noted. Fligh t logs assist with improvements to the systems and expand our safety checklists. The use of lithium batteries has many inherent risks. To mitigate these risks, all team members are trained on safe bat tery handling and usage. Also, all batteries are transported and charged in fiberglass LiPo safe bags. For permanent storage, the batteries are stored in a flammable liquids cabinet. LiPo Battery Care 1. Never charge, discharge, use, or store a damaged or puffy LiPo battery. Immediately follow proper disposal protocols. 2. Avoid purchasing used LiPo batteries. You never know what the previous owner did with them and they could already be badly damaged. LiPo Battery like New, Used Once is usually a scam and should be avoided. 3. Always use a proper LiPo battery balance charger/discharger when charging and discharging your LiPos. It is crucial that all cells in a LiPo battery maintain the same voltage across all cells at all times. If the voltages across the cells deviate too much from each other (5mV ~ 10Mv), the battery can become unstable and dangerous. (Unless it s a single cell LiPo, in which case you do not need to worry about cell balance). 4. Always use a fire proof LiPo safety bag, metal ammo box, or other fire proof container when you are charging, discharging, or storing your LiPo batteries. While LiPo fires are rare, they can happen incredibly quickly and can do a lot of damage. All it takes is an internal short circuit to set the battery off. There is no way to predict when it will happen. It does tend to happen more often when batteries are fully charged, being overcharged, or while being discharged, but it can happen to any LiPo at any time. Never fill the container to capacity with your batteries, always follow manufacturer recommendations on LiPo bags for how many mahs it can safely contain. Do not settle for cheap Chinese knock-off bags! NORFOLK STATE UNIVERSITY TEAM T.A.R.A 17

18 5. Do not use your flight case/travel case for long term LiPo storage. The foam and plastic in these cases can help spread a LiPo fire. Always use a fire proof container such as a metal ammo box or fire proof safe for storage. 6. Never leave your LiPo batteries charging while unattended. If a battery starts to become puffy, smoke, or catches fire you need to be able to immediately handle the situation. Walking away for even just 5 minutes can spell disaster. 7. A LiPo fire is a chemical fire. Always keep a Class D fire extinguisher nearby your battery charging/discharging and storage area. The battery charging/discharging and storage area should be free from any materials which can catch fire such as wood tables, carpet, or gasoline containers. The ideal surface for charging and storing LiPo batteries is concrete or ceramic. 8. Never overcharge a LiPo battery. Typically, a full charge is 4.2v per cell. Never trickle charge a LiPo battery. 9. Never discharge a LiPo battery below 3.0v per cell. Ideally you never want to go below 3.2v per cell to maintain a healthy battery. 2.9v per cell and lower is causing permanent damage. 10. Never leave your LiPo batteries sitting around on a full charge for more than 2-3 days. If by the 3rd day you realize you are not going to use your battery today, you need to discharge your battery down to 3.6v-3.8v per cell for safe storage until you are ready to use the battery again. 11. Always store your LiPo batteries at room temperature. Do not store them in a hot garage, or in a cold refrigerator. Even though a cold battery has less chemical reaction taking place which can prolong its lifespan, taking a battery out from a cold fridge can cause condensation to occur on the inside of the battery, which can be very dangerous. 12. Always remember that heat is the number one enemy of LiPo batteries. The hotter your batteries get, the shorter their lifespan will be. Never charge a battery that is still warm from usage, and never use a battery that is still warm from charging. 13. Depending on how they are used, most LiPo batteries typically do not last longer than 300 charge cycles. Leaving them around on a full or depleted charge all the time, running them completely dead, or exposing them to high temperatures will shorten this lifespan dramatically. 14. LiPo batteries do not work well in cold weather. The colder it is, the shorter your run times will be due to the slowing down of the chemical activity within the battery. If it is below 14F (-10C), LiPo usage is not recommended at all. Your battery could cause your R/C vehicle to suddenly fail without warning in these temperatures. 15. Always pack your LiPo batteries in your carry-on bag and never in your checked baggage when traveling on an airplane. It s the law. Batteries Allowed in Carry-on Bags Dry cell alkaline batteries; typical AA, AAA, C, D, 9-volt, button sized cells, etc. Dry cell rechargeable batteries such as Nickel Metal Hydride (NiMH) and Nickel Cadmium (NiCad). Lithium ion batteries (a.k.a.: rechargeable lithium, lithium polymer, LIPO, secondary lithium). Consumer-sized lithium ion batteries [no more than 8 grams of equivalent lithium content or 100 watt hours (wh) per battery]. This size covers AA, AAA, 9-volt, cell phone, PDA, camera, camcorder, Gameboy, and standard laptop computer batteries. NORFOLK STATE UNIVERSITY TEAM T.A.R.A 18

19 Up to two larger lithium ion batteries (more than 8 grams, up to 25 grams of equivalent lithium content per battery) in their carry-on. This size covers larger extended-life laptop batteries. Most consumer lithium ion batteries are below this size. Lithium metal batteries (a.k.a.: non-rechargeable lithium, primary lithium). These batteries are often used with cameras and other small personal electronics. Consumersized batteries (up to 2 grams of lithium per battery) may be carried. This includes all the typical non-rechargeable batteries for personal film cameras and digital cameras (AA, AAA, 123, CR123A, CR1, CR2, CRV3, CR22, 2CR5, etc.) as well as the flat round lithium button cells. Batteries Allowed in Checked Bags Except for spare (uninstalled) lithium batteries, all the batteries allowed in carry-on baggage are also allowed in checked baggage; however, we recommend that you pack them in your carry-on bag whenever possible. In the cabin, airline flight crews can better monitor conditions, and have access to the batteries or device if a fire does occur. Prohibited Batteries Car batteries, wet batteries, or spillable batteries are prohibited from both carry-on and checked baggage unless they are being used to power a scooter or wheelchair. If you need to pack a spare battery for a scooter or wheelchair, you must advise the aircraft operator so that the battery can be properly packaged for air travel. Spare lithium batteries (both lithium metal and lithium ion/polymer) are prohibited in checked baggage. Packing Tips for Batteries: If you re traveling with spare batteries in addition to the ones inside your devices, consider placing each battery in its own protective case, plastic bag, or package, or place tape across the battery's contacts to isolate terminals. Isolating terminals prevents hazards due to short-circuiting. If you must carry a battery-powered device in any baggage, please package it so it won t accidentally turn on during the flight. If there is an on-off switch or a safety switch, tape it in the "off" position. * Check out the Department of Transportation s spare battery tips page for more information on safely packing spare batteries, and this FAA webpage for more information on permitted and permitted batteries that includes helpful photos. Battery Chargers You can pack battery chargers in carry-on and checked bags. If the charger has an electrical cord, be sure to wrap it tightly around the charger. Don t pack regular batteries in a rechargeable battery charger. Non-rechargeable batteries are not designed for recharging, and become hazardous if placed in a battery charger. NORFOLK STATE UNIVERSITY TEAM T.A.R.A 19

20 NORFOLK STATE UNIVERSITY TEAM T.A.R.A 20