2003 CSU RoverSat

RoverSat: Team Members

Structures:

• Ehren Ehmann

• Christopher Mai

Electronics:

• John Rhoades

• Jesse Wilson

RoverSat: Mission Statement

• The Rover must ride up on a balloon to an altitude of 100,000 ft. and then ride down on a parachute. Upon landing the rover must detach from the parachute, drive away from the landing site, and take at least one picture of its surroundings.

RoverSat: Design Constraints

• The entire package must weigh no more than 750 grams.

• The vehicle must endure a wide range of temperatures, pressures, and humidity.

• The vehicle must detach from the parachute after landing.

• The vehicle must autonomously move from the landing site.

• The vehicle must take at least one picture of the landing site.

RoverSat: Principal Design Breakdown

Structure:• Main Body• Drive System• Release Mechanism• Camera System

Electronics:• Circuits• Microprocessor Programming

RoverSat: Structures Main Body

Constraints

• Must be light weight

• Must be durable

• Must keep out elements

Solution

• Glass Fiber and Epoxy

• Internal frame reinforced with PC Board

RoverSat: Structures Drive System

Constraints• Must be Durable• Must withstand landing

impact• Must provide adequate

traction and torque for movement

Solution• PC board wheels with

rubber traction• Servo Drive

RoverSat: Structures Release Mechanism

Constraints

• Must prevent rover from being tangled on line

• Must not disconnect from line early

Solution

• Down tube running length of rover

• Servo actuated release

RoverSat: StructuresCamera System

Constraints• Must be operable in any

orientation• Must be weather proof• Must provide stable

platformSolution• Camera can protrude from

either top or bottom• Servo actuated movement• PC Board mount

RoverSat: Control SystemsOverview

Constraints• Fully autonomous• Able to operate in-

flight, withstanding temperature, pressure…

• Light weight• Reliable

RoverSat: Control SystemsComponents

• Power: Energizer lithium photo batteries

• CPU: Atmel MegaAVR 8-bit RISC

• Control: Toshiba Darlington pair driver chip

• All components rated to at least -40º C

• Fuses to ensure one bad component won’t debilitate entire system

RoverSat: Control SystemsSoftware

• Written in Atmel assembly

Power-up/standby

Launch

Timer Release/Deploy

Drive

Take Picture

RoverSat: Control SystemsElectronics

• Custom-designed PC board

• Designed using CadSoft EAGLE

• Printed by Advanced Circuits

• Hand-assembled and soldered

RoverSat: Control SystemsController Board

RoverSat: Flight DayPre-Flight

• Upon prep of the vehicle it was determined that the program was unreliable so the decision was made to send it up without the microprocessor.

• The structure was tested to make sure it could survive the impact.

RoverSat: Flight DayPost-Flight Evaluation

• The structure was intact upon landing

• There were no signs of damage to the drive train, camera, or external structure after removing it from the tether.

RoverSat: Conclusion

The DemoSat program allowed for a huge degree of design freedom and allowed our group members to learn not only about the design process but group dynamics and how to succeed not only as an individual but as a team. Leaving the project at the end of the ten-week program left us more prepared for our senior design projects and more prepared to utilize the tools that we have been learning for the last few years.