Google Lunar X PRIZE Competitor Using ANSYS Engineering Simulation Software in Developing Robot to Explore Moon’s Surface
As an official sponsor of the Astrobotic lunar project, ANSYS is providing its multiphysics engineering simulation software and applications support. The technology is being used in the development of the robot, the four-legged lander and a payload adapter connecting the robot to the launch vehicle.
In developing the concept design for the assemblies, extensive analysis was performed using ANSYS Mechanical software in determining stress distributions of major components and assembles in withstanding up to 13 Gs of acceleration and vibration loads encountered during launch, stage separation, orbital insertion and landing.
Engineers focused in particular on analysis of the robot’s all-composite structure — a groundbreaking innovation in lunar rover design intended to combine high strength and stiffness with the ability to keep the machine cool. Simulations also studied the effectiveness of the payload adapter in withstanding these extreme loads and having sufficient structural flexibility to damp the transfer of damaging vibrations from the launch vehicle to the robot. Numerous simulations were performed in evaluating different adapter geometries and materials, including titanium and aluminum as well as various combinations of solid, sandwiched and honeycombed carbon-fiber composite materials.
In these simulations, engineers conducted parametric design optimization studies using ANSYS DesignXplorer software and the scripting capabilities of the ANSYS Parametric Design Language (APDL). Through hundreds of iterations performed automatically in just a few hours, engineers leveraged the software to find the lowest-cost, lightest-weight designs for the robot and the deep-space transfer stage that will deliver it to the moon. ANSYS simulation technology enabled the research team to examine alternative structures and materials to find the most effective combination in the early concept stages of development, before physical prototypes were built.
In these simulations, ANSYS contact elements were used in models to automatically transfer mechanical force loads across joints between mating parts, instead of performing this task manually. The same contact elements were used in transferring thermal energy loads across these boundaries in exhaustive simulations to study heat flow and temperatures in the robot structure.
These studies performed with the thermal analysis capabilities of ANSYS Mechanical software were instru-mental in helping engineers to determine an optimal robot design to survive the large temperature variations and heat dissipation challenges of the lunar environment. Lunar areas lit by the sun are baked at 100 degrees C, while temperatures plummet to minus 180 degrees C at night — a drastic thermal difference ranging from the temperature of boiling water to that of liquid nitrogen. Engineers had to consider this thermal cycling because differences in thermal expansions of various components cause conventional fasteners, solder joints, snap fits other parts to pop, fracture, and otherwise degrade.
Compounding the difficulties, the almost nonexistent atmosphere on the moon means that there is no convection cooling. Fans, therefore, are absolutely ineffective in removing thermal energy from internal elec-tronic and electrical components for control circuitry, motors and actuators. Moreover, lunar regolith — the powdery dust covering the surface of the moon — is highly insulative, reflecting radiant energy from the sun and any internally generated heat back onto the robot.
Engineers solved the problem of removing waste heat from the robot by installing a large white panel on the robot’s side that will always face away from the sun, which will radiate excess heat to black space.
Numerous simulations were performed to find the optimal surface area and orientation of the radiator as well as to study sunlight hitting the robot at different angles — to explore the effectiveness of the various asymmetrical shapes of the robot outer shell and to evaluate the thermal conduc-tivities of the composite structure of the robot.
ANSYS multiphysics simulation was instrumental in evaluating hundreds of these complex mechanical and thermal loading scenarios. Performing these studies using software with wide-ranging advanced technology enabled the Astrobotic Technology engineering team to optimize the structure during the early concept stages of develop-ment. The technology will be used for more in-depth studies as the robot and support equipment proceed through detailed design phases. Optimizing the design of complex assemblies to operate properly under such adverse conditions would not be practical without the ability to performing exhaustive simulations so quickly.
Engineers calculated static stresses on the cone-shaped payload adapter from mechanical loads that would be encountered during launch, rocket stage separation and orbital insertion.
The original news release:
SOUTHPOINTE, PA – November 9, 2009 – ANSYS, Inc. (NASDAQ: ANSS), a global innovator of simulation software and technologies designed to optimize product development processes, today announced that it has become an official sponsor of Astrobotic Technology Inc.’s Tranquility Trek™ mission, which involves developing a rocket-launched robot as part of the Google Lunar X PRIZE competition. As sponsor, ANSYS is providing its multiphysics engineering simulation software in the development of the robot, lander and payload adapter as the company races to become the first privately funded team to reach the Moon. Through the use of tools from ANSYS, Astrobotic Technology is simulating the effectiveness of machinery and materials performance under extreme fluctuations in lunar conditions — all to be conducted prior to sending the robot to the Moon. The project will pave the way for human exploration and eventual tapping of lunar resources for export to Earth.
The Google Lunar X PRIZE is a $30 million competition to encourage privately funded teams to send a robot to the Moon, travel 500 meters, and transmit video, images and data back to the Earth. U.S.-based Astrobotic is one of 21 teams from around the world participating in the competition. The company, which has identified a 2011 launch date, already is field-testing prototype Moon robots.
“This is a race after all, so we are leveraging engineering simulation software from ANSYS to keep moving at warp speed,” said David Gump, president of Astrobotic Technology Inc. “We are applying the software to find the lowest-cost, lightest-weight designs for our robots and the deep-space transfer stages that will deliver them from Earth’s orbit to the Moon. ANSYS® technology enables us to examine alternative structures and materials to rapidly find the most effective combinations via simulation, before we build physical prototypes.” For example, Astrobotic Technology will use tools from ANSYS to design the composite structures of the landing stage and then model the impact forces it will experience when it touches down on the Moon.
Surviving the Moon’s environment, which exhibits drastic temperature changes, is proving to be a complex challenge. “The Moon is a harsh world to explore. At noon, for instance, our robots will be baked at 244 degrees Fahrenheit, according to the latest readings from NASA. Our third prototype, created by our partners at Carnegie Mellon University utilizing ANSYS technology, demonstrates how to beat the heat with an innovative asymmetrical shape. The software’s thermal analysis capabilities help us determine the optimal design to withstand the Moon’s elements,” Gump explained.
“Astrobotic Technology’s choice of ANSYS software for Simulation Driven Product Development™ will serve it well during its race to the Moon,” said Jim Cashman, president and CEO, ANSYS, Inc. “This may turn out to be the ultimate in virtual research, since it is impossible to physically reproduce the lunar environment then run prototype experiments in out-of-this-world conditions. The entire mission holds the opportunity for the world to gain insight into new discoveries yet to be found.”
Once the robot reaches the Moon, Astrobotic Technology intends for it to visit Apollo 11’s landing site along the equator and to study the lunar environment’s effects on materials that mission left behind.
About the Google Lunar X PRIZE
The Google Lunar X PRIZE is a $30 million competition for the first privately funded team to send a robot to the Moon, travel 500 meters, and transmit video, images and data back to the Earth. Teams must secure no more than 10 percent of their funding from governments and deliver their video in HD quality. The first team to land on the Moon and complete the mission objectives will be awarded $20 million, with $5 million for second place and $5 million for bonus events. The final deadline for winning the prize is December 31, 2014.
About Astrobotic Technology Inc.
Astrobotic Technology Inc. was founded by Red Whittaker, a world leader in advanced field robotics. The company is a spin-off from the Robotics Institute at Carnegie Mellon University, where initial prototypes of its Moon robot have been designed and tested. The first mission of Astrobotic Technology, the Tranquility Trek™, will launch to the Moon on a commercially available booster, win the Google Lunar X PRIZE, and show the world the Apollo 11 site in high-definition video. Tranquility Trek will demonstrate the first precision robotic landing on another world, essential to Astrobotic’s long-term business of supporting the science objectives and lunar outposts of NASA and other space agencies. For more information, visit www.astrobotic.net.
About ANSYS, Inc.
ANSYS, Inc., founded in 1970, develops and globally markets engineering simulation software and technologies widely used by engineers and designers across a broad spectrum of industries. The Company focuses on the development of open and flexible solutions that enable users to analyze designs directly on the desktop, providing a common platform for fast, efficient and cost-conscious product development, from design concept to final-stage testing and validation. The Company and its global network of channel partners provide sales, support and training for customers. Headquartered in Canonsburg, Pennsylvania, U.S.A., with more than 60 strategic sales locations throughout the world, ANSYS, Inc. and its subsidiaries employ over 1,600 people and distribute ANSYS products through a network of channel partners in over 40 countries. Visit www.ansys.com for more information.
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