Strong-Arm Tactics
Students examine the importance of a robotic armCopyright National Aeronautics and Space Administration, http://www.nasa.gov/multimedia/imagegallery/image_feature_282.html
Why do we care about a robotic arm? What does a robotic arm have to do with engineering? Creating such an arm comes from a design that involves mechanical, electrical, and computer science engineers. As expected, students generally do not know the complexity that goes into building and programming a robotic arm. This activity allows students to control a robotic arm from both a machine's and a computer science engineer's perspective by performing a simple task with a few instructions and constraints.
The original engineering design requirements for the Spirit and Opportunity rovers included a single robotic arm with an extensive range of motion and ability to hold four inspection instruments. With the advancement of technology through engineering applications, engineers at NASA determined that a more advanced arm was needed. So engineers worked together to make a more useful, functional arm for their rover. The final robotic arm has five degrees of freedom and is capable of moving in just about any direction. This movement is enabled by three joints, a shoulder, elbow and wrist, which the engineers modeled after a human arm. To provide the five degrees of freedom, mechanical engineers used many geared motors at the shoulder, elbow and wrist. The technology of the robotic arm has continued to improve and on NASA's Perseverance rover the robotic arm is seven feet long and can hold and use tools to extract cores from rocks, take microscopic images and analyze the mineral makeup and elemental composition of Martian soil and rocks.
Robotic Arm.Copyright http://oceanexplorer.noaa.gov/explorations/ 02davidson/logs/may20/may20.html
After this activity, students should be able to:
- Describe similarities and differences between human arms and robotic arms.
- Articulate about challenges engineers face when designing robotic arms.
- Define degrees of freedom and understand how a robotic arm depends on its number of degrees of freedom.
- Explain cause-effect relationships between control commands and outcomes within a system.