Team Cheese
From TeamFrednetWiki
Team Cheese (TC) is a group of four mechanical engineering undergraduates at Queen’s University (Ontario, Canada) who made contributions to Team FREDNET while fulfilling a student capstone design project during the Fall of 2009. TC tackled the challenging task of designing and building the systems necessary to land a functional rover on the moon. During this process, TC designed a conceptual landing system that will limit the impact loading on an unmanned lunar landing craft during touchdown.
TeamCheese.com is a blog that TC maintained while making progress on the project.
Summary
In their fourth year of the mechanical engineering degree at Queen’s University in Kingston Ontario in Canada, students are encouraged to seek the sponsorship of industry clients in a mutually beneficial design project aiming to prepare graduating students for the workforce by working on real-world team design problems. As part of their student project with Queen’s University, Team Cheese, a group of four graduating mechanical engineers at Queen’s University, sought the sponsorship by Team FREDNET, a registered official team competing for the Google Lunar X Prize. Team FREDNET is a special competitor as it consists of an international group of developers, engineers, scientists and other members dedicated to the open source philosophy. The partnership contributed positively to the education and experience of the students, immersing them in a diverse and engaging community which would in turn benefit from the design efforts of students.
Over the fall semester Team Cheese has worked with Team FREDNET to design a conceptual landing system for their lunar module. With the help of the Team FREDNET community and the faculty members at Queen’s University, Team Cheese was able to design a preliminary conceptual lunar landing gear system. The design was created within several operating constraints proposed by Team FREDNET and incorporated key design aspects of energy absorption, structural design, and touched on landing pad considerations.
The energy absorption system chosen incorporated plastically deforming metal cartridiges .12 m long with cross-sectional diameters of .01905 m housed in the secondary struts of a three legged angled lever pod structure. As the propagated uncertainty associated with preliminary mission specifications (lander mass, free fall height, surface characteristics) was very high, a safety factor in design was omitted for the sake of proving that a worst case acceleration developed on the lander could be limited to beneath the 10 gee constraint.
Through the use of Matlab optimization, key relationships were evaluated to determine dimensions. The final inside diameter of the primary strut was optimal at 3cm, and the final outside diameter of the primary strut was optimal at 3.25cm for a structure made of titanium. The angle between the primary strut and the vertical (theta) was found to be 20 degrees, and the angle between the secondary strut and the primary strut (alpha) was found to be 50 degrees. The length between the primary strut interface to the lunar module, and the secondary strut interface to the primary strut (a) was found to be 0.4m. The inside diameter of the secondary strut was found to be 1.905cm and the outside diameter was found to be 2.35cm.
A brief landing pad analysis explored designs and justified its structural rigidity showing that with a contact area of 0.071m2 a regolith penetration of approximately 8cm and a force of 14KN developed on the landing module would result. An acceleration of approximately 7 G’s in the worst case would be experienced by the landing module
Concerning the landing gear system, further design efforts, analysis and prototyping can continue from a sound foundation as a result of the project work. Their effort has been documented on their blog (http://teamcheese.com) and is available on the Team FREDNET wiki for scrutiny and further design progress.
Group members: http://teamcheese.com/?page_id=6
