Actual Plan

I have written a proposal which I have given to some of my potential sponsors. Below is a copy of the relevant parts. I have also named the Balloon The XBR Alpha, for Experimental Robotic Balloon Alpha.



Goal-

The goal of this project is to design, build, and test an automated hot air balloon. The balloon will be able to take off, fly, and land on its own. It will also be able to chart its own path, and eventually, predict landing locations. A laptop computer on the ground will be able to track the balloon using a program created in LabView.


Construction-

The balloon envelope will be constructed from 3/4 oz rip stop nylon, using 12 vertical gores, and one horizontal panel. The fabric is cut into gore shapes, then sewn together to form the entire envelope. The top of the balloon is attached with Velcro, so it may be removed to deflate the balloon. Load tapes, cords running down the balloon to lessen pressure on the fabric, are added. The basket is attached to these cords. The basket is constructed from aluminum, and carries all the controls for the balloon. Normally, the basket carries propane fuel, and a burner. The burner operates by first vaporizing the liquid propane, and burning the vapor to create an intense flame. In addition to these devices, the XRB Alpha will also carry electrical equipment to control the balloon. The heart of the electronic controls is a BASIC STAMP, a small, low power microcontroller that controls the other elements of the balloon. To start, the STAMP will control the burner via a binary servo valve, located in the basket. The STAMP may also eventually control the deflation valve. In addition, the STAMP will also gather information from an array of sensors, including a Global Positioning System (GPS) receiver, an anemometer, ultrasonic altimeter, ground contact sensor, and flame sensor. The role of these sensors is explained under “Flight”. The balloon will also be equipped with a two way serial radio for communication with a laptop on the ground.

Flight-

The balloon will be inflated with cold air by hand while it lies on the ground. After it has been inflated, an initial, human controlled firing of the burner (or burn) will take place. This will heat the air inside the balloon so that it rises to an upright position. Control is now switched over to XRB Alpha by turning on the control systems. The BASIC STAMP will initiate all of the required sensors, and confirm that the ground contact sensor is tripped. The XBR Alpha will then initiate a burn, until data from the GPS indicates that the balloon is rising. Following a preprogrammed flight plan, the

XRB Alpha will achieve a desired altitude, as measured by the GPS, and then begin its descent. To descend, the XRB Alpha will execute fewer burns, allowing the temperature in the envelope to fall, and in turn, allowing the balloon to descend. The BASIC STAMP will ensure that the balloon does not fall too quickly by taking readings from the GPS. The balloon will rely on the altitude given by the GPS until the ultrasonic altimeter detects that the balloon is 9 feet above the ground. The ultrasonic altimeter is necessary because the accuracy of the GPS is not accurate enough to determine the balloons altitude within this distance. Once the BASIC STAMP begins taking readings from the ultrasonic altimeter, it will slow the descent until it detects the ground via the ground contact sensor.

Laptop-

Throughout the entire flight, the XRB Alpha will be in contact with a laptop computer on the ground via a wireless serial radio. Through a program created in LabView, the user will be able to monitor the altitude, location, horizontal and vertical speeds, wind speed, and eventually, a video feed. The laptop will also provide a way to control the balloon manually, in the event that it is necessary.