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Using Telescience to Share NASA Resources During the Classroom
Study of a Mars Sample and Return Mission - page 2
Richard Hooper and SV Sreenivasan
Department of Mechanical Engineering
The University of Texas
Austin, Texas 78712 |
Donald A Morrison
Earth Science and Solar System Exploration Division
NASA/Johnson Space Center
Houston, Texas 77058 |
Proceedings of the ASEE Gulf-Southwest Annual Conference, The University of Houston, March 23-25, 1997 |
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Table 1. shows the Mars sampling projects functioning as a motivator and initiator. The projects should motivate the students by giving them an exciting application context (searching for traces of life in the solar system) in which to interpret their dynamics studies. The projects naturally function as initiators by providing open-ended design problems for the students to pursue at their own pace. One might also argue that the design projects can function to coach the students by requiring reports and design reviews. Though true, in this context the projects function very much like traditional homework and do not bring significant new coaching resources. The transport lag experiment functions as an expert by presenting derivations in a logical and organized fashion. The experiment also functions to motivate the students by giving them hands-on experience with state-of-the-art equipment. Finally, the experiment serves to reinforce the project work because a manipulator with a gripper is one of the options the students will consider in their design projects. The telepresentation by NASA should motivate the students by giving them an application context and also by exposing them to practicing scientists and engineers. The "Email with Expert" component functions primarily to motivate the students by giving them rapid feedback and exposing them to practicing scientists and engineers. Again one might argue that the "Email with Expert" component is functioning as a coach by providing feedback. In this case the component functions much like a professor providing students help with their homework during office hours and thus brings no unique coaching resources.
Traditional lectures, homework, and examinations comprise the final three course components in Table 1. Notice that these three components can cover all four roles in the Kolb learning style model. This illustrates something experienced by most students: teachers can teach effectively using only traditional lecture, homework, and examinations. Traditional lecture naturally functions in the role of expert. Traditional homework and examinations naturally function in the role of coach. The challenge lies in using these course components to motivate and initiate the students as well. To motivate the students, lecture topics, homework problems, and examination problems can show relevance using an application or phenomenologic context. To initiate student exploration, some possibilities include: open-ended problems, group problem solving, design projects, and brainstorming activities. A quote from a professor at UT seems appropriate here: "Omitting a single piece of information changes an analysis problem into a design problem."
As for the Advanced Dynamics of Robotic Systems course, an examination of Table 1. shows the course is already spending quite a bit of time as a motivator. Therefore, the traditional lecture component of the course does not focus too heavily on motivating. Rather, the goal is to make the lecture as effective as possible. Robots come in all shapes, sizes, and geometries, including: mobile platforms, serial-chain manipulators, and multi-loop closed chains. This necessitates a methodology for describing robot geometry that is quite general. To offset this generality, the lecture includes a running example robot that relates to the Mars sample-and-return design project. This robot consists of an articulated arm mounted to a wheeled vehicle. The end-effector of the arm is a three fingered gripper. This sort of configuration is one possibility the students will consider in their design project. This configuration is also a specific example of the most general case: the wheeled vehicle is a mobility platform; the articulated arm is a serial-chain manipulator; and the three-fingered gripper is a closed-loop chain. When the lectures develop general expressions, the example robot shows the specifics. Felder suggests sometimes proceeding from the general to the specific and sometimes proceeding from the specific to the general [4]. This is to reach both inductive and deductive learners.
Because the design projects divert a significant amount of time towards initiating and motivating, the homework and examinations in the Advanced Dynamics of Robotic Systems course remain essentially problemsolving exercises. The problem statements include descriptions of the problem's application relevance, but the problems themselves remain quite traditional. This is because the instructors believe students learn the mechanics of problem solving primarily through homework and examination course components. This is probably the most striking feature in Table l . - only traditional homework and examinations function in the role of coach. This indicates that - regardless of what other course components there are - the students will only be able to solve dynamics problems if they practice solving dynamics problems. None of the course components listed in the table will substitute for solving practice problems. Indeed, the table shows that an instructor should exercise caution before diverting too much of the students time away from practice problems and traditional examinations.
Mars Sample and
Return Components
This section of the paper describes the four course components developed and currently in implementation as part of the Mars sample-and-return focus. The components include semester-long design projects, an integrated lecture and tele-demonstration, a tele-presentation by JSC geologists, and email with JSC experts. They are all well-suited to situations where equipment and expertise are located many miles from the teaching
campus.
Mars Sampling Projects
The course includes semester-long design projects to motivate the students and provide them opportunities for independent exploration and learning. NASA requirements for a portion of the Mars sample and return mission form the basis for the projects. The following lists and briefly describes these projects:
1. Acquire and Stow - Acquire rounded to angular objects between "x" and "y" cm. in diameter and place
them into a container.
2. Trench and Sieve - Capture objects larger than one cm. in diameter by sieving a particulate material.
Place the qbjects into a storage container and determine geotechnical properties derivable from the operation.
3. Clean Solar Cells - Acquire a tool and use it to clean solar cells located within a radius of three meters.
Forces applied to the cells must be controlled.
4. Drill and Core - Drill vertically into the Martian surface and withdraw a drill string from ten to onehundred
cm. in length.
Dividing the students into four groups gives a small team of students (2-4) for each project. Each project requires individual as well as group work. The four groups also meet together periodically as one larger group to discuss solutions and possibilities for collaboration. For example, one mechanism may be capable of performing more than one of the project tasks. This arrangement gives the students experience with working independently, in small groups, and in larger groups.
These projects should motivate the students by giving them an exciting application context in which to interpret the lecture material. Each of the projects requires a mechanism of some sort to exert forces on and interact with the environment. Exerting forces at the work point in turn requires the mechanism to exert forces , (or torques) at each of its joints. The students must use analytical techniques presented in class to calculate the necessary joint forces and torques given operational requirements. This gives the students a clear application context.
As design projects, the Mars sample-and-return application has some interesting attributes that force students to examine requirements they might otherwise have missed. For example, extreme environmental conditions exist on the Martian surface. These conditions influence the selection of materials and components. The long duration and high-expense of the mission demands designs that are extremely reliable. Finally, these projects are very open-ended. There are no clear solutions and examples of existing solutions are rare. This forces the students to think for themselves and search for solutions.
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