Tensegrity Internal Actuation

The goal is to design an actuated internal payload to provide a locomotion method for the NASA SuperBall tensegrity robot.
== Problem Definition ==
===Background===
Tensegrity is a design term meaning Tensile Integrity. This describes the construction of a tensegrity structure. Every member in a tensegrity is either in pure tension or pure compression which eliminates the need to compensate for bending moments and allows designs to be light weight with simple cross-sections. Our tensegrity structure is a 6 strut model. 
NASA's SuperBall Tensegrity robot is a NASA Innovative Advanced Concepts (NIAC) project with the goal of developing an exploratory tensegrity robot. In previous years student's have developed the tensegrity structure of the robot, and through rigorous analysis and testing the structure has been validated for a space drop on to Saturn's moon, Titan. Currently there are two projects underway, one of which being here at the University of Idaho where locomotion of the robot through internal actuation is being developed. In other labs the actuation of the external frame is being explored.		
===Deliverables===
After consulting with NASA Tensegrity leaders a list of deliverables was developed. The deleverables and current status are summarized below. 
Catagory 	
Metric 	
Priority	
Current Status
Controls Location 	On Board 	Minimum	Complete
 	Tethered 	Desired	Complete
Controls Method 	Manual 	Minimum	Complete
 	Pre-Programmed 	Luxury 	Incomplete
Power Location 	On Board 	Desired	In progress
 	Tethered 	Minimum	Complete
Battery Life 	30 mins 	Desired	In progress
 	>30 mins 	Luxury 	In progress
Actuators Type 	Brushless DC motors 	Desired	Incomplete
 	Brushed DC motors 	Minimum	Complete
Scientific Payload Mass	2 kg 	Minimum	Complete
 	5 kg 	Desired	Complete
 	>5 kg 	Luxury 	Complete
Sensors 	Encoders 	Minimum	N/A
 	IMU 	Minimum	In progress
 	Tension 	Desired	Incomplete
 	Absolute Position 	Luxury 	Complete
Locomotion Distance 	Payload to tipping point (no tip)	Minimum	Complete
 	1 Tip of structure 	Minimum	Complete
 	10 Tips of structure 	Desired	Incomplete
===Specifications===
The final prototype will have the following specifications.
*Have 12 actuators 
*Have a sensor calibration sequence 
*Be able to move around inside the tensegrity structure
*Generate locomotion by tipping the tensegrity structure
== Project Learning ==
Currently there are three major categories to this design: Mechanical Design, Payload Kinematics, Controller Design, and Position Measurement
===Mechanical Design===
Payload Prototype	 	 	
	Prototype I - utilizes laser cut wood, aluminum mounts and spools and encoder positions	Prototype II - utilizes previous design with 10-turn potentiometers with geared inputs	Prototype III - utilizes previous design with new controllers
===Payload Kinematics===
 	 	
Using MATLAB a kinematic model was built to understand cable lengths, tipping mechanics, and payload kinematics.	Isosceles face has a point to point trajectory.	Equilateral faces require an intermediate point trajectory
===Controller Design===
Payload Control Scheme	 	 	
	Controller I - utilizes Teensy 3.1 controller, Adafruit PWM driver, and encoders for position measurement	Controller II - utilizes Arduino Mega controller and 10-turn potentiometers for position measurement	Controller III - utilizes 1 Teensy 3.1 Master and 6 Baby Orangutan Slave microcontrollers. It uses a 10-Turn potentiometer for position measurement.
===Position Measurement===
Measurement Options	 	 	
	Measurement I - utilizes existing encoders for cable length measurements	Measurement II - utilizes a multi-turn potentiometer for cable length measurements	Measurement III - utilizes 10-turn potentiometers with a 4:1 gear ratio for cable length measurements
Chose Measurement III	 	 	
	Front View 	Side View 	
==Team Information==
Team TITAN: Amy, Kelsey, James, Mark, and Dylan
Picture 	Bio 	Discipline
 	Amy Wohlschlegel	
Amy is a computer engineering major from Boise, Idaho as well as a proud member of Delta Zeta sorority. In her spare time she loves to hunt, fish, camp, sing and play rugby.	 	
==Document Archive==
==Video Archive==
Full Isosceles Tip
Soft Equilateral Tip
NASA Ames Superball Tip