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Flying Fish

Battery:
Capacity 90mAh
Voltage 3.7v Single Cell
Weight 3.0g
Dimensions 14.5mm x 23mm x 4.8mm
Max Discharge 15C (1350mA)
Connector Type 10mm Bahoma
http://www.microflight.com/Online-Catalog/Batteries-and-Chargers/LP90-FR-Bahoma-Cell-with-10mm-Bahoma

Servos:
Weight 2.5g
Dimensions 20x8x16mm
Torque 0.15kg/cm @ 4.8v
Speed 0.12sec / 60deg no load
Current 100mA Average
http://www.microflight.com/Online-Catalog/Actuators-and-Servos/Blue-Arrow-2-5g-Servo
http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=3714&Product_Name=HobbyKing_Blue-Arrow_2.5g_/_.17kg_/_.12sec_Micro_Servo

Weight 3.9g
Torgue 0.18kg/cm
Speed 0.1sec / 60deg no load
http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9904&Product_Name=Blue_Arrow__3.9g_/_.18kg_/_.10sec_High_Speed_Micro_Servo

Receiver:
Weight 1.1g (0.7g w/o connectors)
Dimensions 23 mm x 14 mm x 6 mm
Channels (4) Rudder, Aileron, Elevator, Throttle
Recommended Servos Blue Arrow 2.5g and SmartServo RC-1
Servo Connector Type Mini JST
Recommended Motors 7mm Gearbox, N20, Brushless
Brushed Motor Connector Type Nano-connector (1.27mm pitch)
Recommended ESC Current Anything less than 2 Amps
Recommended Batteries Lithium Polymer LP90 - LP200
Battery Connector Type Mini JST
Recommended Input Voltage 2.8 - 10vdc, 2 cell Capable
Range 100m
Antenna Length 78mm (2 external wire dipole)
Recommended Transmitter HFX900, Monolith, HFX868 M1 and M2
Frequencies UHF 900Mhz and 868Mhz ISM bands
Resolution 127 steps - fully proportional
Elevon Mixing Yes - selected on Transmitter
Negative Exponential Yes - selected on Transmitter
Servo Reversing Yes - selected on receiver or Transmitter
Brushless capable? Yes, ready for BL ESC
http://www.microflight.com/Online-Catalog/Receivers/Micro9-S-4CH-1-1g-Servo-Rx-w-ESC

Buying Parts: 1) HobbyKing.com is located in Hong Kong. It takes a few more days to get the parts but the parts are typically much cheaper and the quality has not been a problem. 2) http://www.microflight.com/ has extremely light weight parts. They are located in Canada and ship very quickly, however, we have had problems with a few servos going bad quickly.

Directions for creating a blimp envelope (balloon):

1) Create a pattern for the Mylar:

a) Choose your basic plan and create a scaled sketch of it. Measure the diameter at key points along your drawing and convert the measurements into circumference values. b) Divide the circumference values by the number of pieces you intend to use to construct the blimp envelope, and add one inch for the seal on each side. c) Take a large sheet of paper and use the values you found in part (b) to measure and create a paper pattern. For best results, draw 1/4th of the pattern, then fold the paper and trace it to create a symmetric pattern (in the event that your design is only symmetric along a single axis, draw 1/2 of the pattern before folding and tracing). d) Cut out the pattern and ensure that it is symmetric and according to your plans.

2) Prepare the Mylar pieces:

a) Lay the pattern top of the mylar (reflective side up) and trace the pattern. Two of the pieces will need additional mylar to be made into an opening for the helium. Remember that the reflective sides will need to be on the outside of the blimp and be careful to make sure the two extra mylar parts for the helium opening will line up properly. You may need to flip your pattern before making the second piece with extra material. b) Cut out the traced pieces of mylar.

3) Seal the pieces of mylar to form the envelope.

a) Plug in the iron and allow it to fully heat before beginning. If the iron needs to be calibrated, then prepare test pieces while the iron heats. Test the iron by sealing two pieces together, allow the seal to completely cool, and then try to slowly pull it apart. The two pieces should provide resistance and slowly come apart when force is applied. If the seal is ineffective, adjust the settings and allow the iron temperature to stabilize before resuming. If the iron is too cool, the seal won't form properly. If the iron is too hot, it will make small holes in the mylar. b) Line up the pieces of mylar very carefully, and then touch the iron to the mylar in several places to cause the mylar to stick together and hold its location. Connect all the pieces then proceed to seal the mylar together by gently pressing the iron on the mylar and moving towards the outside. Your seal should cover between 1/2“-1”. Work from the middle towards the outside, and (when dealing with more than two pieces) seal the end points last. REMEMBER: The reflective side needs to be on the outside as the dull side melts to create the seal.

Simulation Files

Simulation 1: Simulation files developed by Colin Edwards in Winter 2010. Documentation is provided at Zeppelin_Simulation_Guide.

System Overview

Components

* Blimp Servos (2) - actuate the tail. Servo 1 moves left/right. Servo 2 moves up/down. * R/C Receiver - Receives radio signals and outputs servo commands. There are two receivers:

  • 72 MHz receiver (in the box) - heavier, but uses a standard frequency.
  • 900 MHz receiver (very tiny red board) - very light, but must use a plantraco transmitter to control it.

* R/C Transmitter - Receives commands via its trainer port (plug on back) or from joysticks and transmitts them to the receiver. The trainer port uses a standard R/C signal format called PPM. You can google “trainer port ppm” for more information. * PCTx USB to trainer port interface - Allows programs on the computer to command servo positions. It interfaces with the computer via USB and accepts commands (see PCTxServoController.h for more information) and translates those commands to PPM that the R/C transmitter can understand.

Connections

The servos are controlled just as they would be on a standard R/C plane. A standard 72 MHz R/C transmitter sends desired servo positions to the R/C receiver, that then commands the servos. The user presses up on the stick, the servo moves to that position.

The control code on the computer talks to R/C transmitter via its trainer port. A PCTx (purchased online, google it) translates USB commands to PPM signals that the transmitter can understand.

Control Code ←-USB–> PCTx ←-PPM Signal–> R/C Transmitter <~~~ RF ~~~> R/C Receiver ←–> Servos

Notes

* We also have a 900 MHz transmitter board. It's the long board with a trainer port connection on one side and couple of wires on the other end. I (Brian) seem to have killed it during testing. Initially I thought that the voltage regulator was the problem, but it appears to be a short on the board itself. An inexpensive cable can be purchased to interface the other 900 MHz transmitter (with control sticks) to a standard trainer port. This can be found on plantraco's site.

* (Brian) For testing I used my own Futaba transmitter. The magic lab transmitters have a different shaped trainer port, but use the same PPM signal. You just need to hook things up right. See: http://users.belgacom.net/TX2TX/tx2tx/english/tx2txgb7.htm figure 7f-12.

Controller Code (Winter 2010)

Code found here: blimp_controller.zip

Let me know if you need more comments on any of the files - Brian

Spring Semester Tasks

  1. Hardware
    1. (optional) Switch to 900 MHz or find lighter 72 MHz
    2. Purchase tank
    3. Add valve to fill tight
    4. Replace large cables with lower gauge cable
    5. Make flapper more robust
  2. Software
    1. Learn how to use Cortex
    2. Connect Brian's software to Cortex
    3. Connect Colin's simulation to Brian's control code
      1. Understand model - refine model from experiments

Contact Information

  1. Colin Edward
    1. E-mail: colin.edward (at) gmail (dot) com
    2. Cell: (240)434-8238
  2. Steven Reeves
    1. E-mail: stevenreeves1 (at) gmail (dot) com
  3. Weston Hullinger
    1. E-mail: wjhullinger (at) gmail (dot) com
  4. Thomas Perry
    1. E-mail: thomaseperry (at) gmail (dot) com

Winter 2010

  1. Brian Pendleton
    1. Email: brianpen (at) byu (dot) net