Individual Robot Analysis

• Saturday, one day after last day of classes at 8:00 pm (Fall 2019: December 7)
• Submit electronic copy by 8:00 pm through gradescope
• Turn hardcopy into large plastic bin in EBU2-239

A team member CAN analyze a piece of hardware that was built but was not incorporated in the final robot design as long as the component functions to the point where one can compare theoretical predictions and part performance (or failure to perform). If you spent a lot of time working on part of the machine that did not pan out, still consider using it for your analysis.

When doing the clock report, we discussed what a good report looks like, from the technical writing style to the organization and the sections include. Please revisit these topics as you write the robot report.

Grading Guidelines

The individual analysis will be graded on clarity of text and graphical content as well as correctness of analysis. It is recommended that reports be printed in color and presented professionally.  The analysis section will consider the complexity of the analysis. If a relatively simple part of a machine is being analyzed, then a high grade will require more in-depth analysis, such as: consideration of friction and the motor torque-speed curve. The instructor(s) will be looking for a critical assessment of machine performance and a meaningful explanation of experimental results and how they may vary from theoretical expectation.

Part I: Description of Component (2 page max) (25%)

In this section you should introduce your entire robot's design, what it does, and introduce the component you intend to analyze. It should be be clear to a naive reader how your robot works. This section should include:

• 3D CAD of complete machine with annotations. It should be clear how overall machine works.
• 3D CAD of component with annotations. You should show how details of component work. Include multiple views if it helps.
• Photo of your robot
• Minimum Set of Functional Requirements of your component
• What the component needs to accomplish (not how it was accomplished)
• List each FR as a one sentence bullet. Indicate quantitative values where appropriate
• Example: "Robot must reach middle of table in 10 seconds."
• Overview of how well component functioned. Give numerical values (e.g. speed, points, maximum mass lifted, etc...)

Part II: Analysis of Component (60%)

• The FBD must be digitally generated.
• Recommended approach:
• Create an Inventor drawing of your component with the proper view for the FBD
• Save the drawing as a image file
• Crop and add the force vectors and lengths in Powerpoint
• Create a table or list which shows all the physical parameters (actual numbers) used in the FBD and analysis
• Reminder: only external forces acting ON your component should appear in the FBD!

• You should describe your assumptions in less than one sentence
• Indicate if the assumptions is conservative or optimistic
• Example: Point-mass Assumption: masses are concentrated at points as shown in the FBD above (optimistic).

• Use an equation editor:  
• Microsoft word equation editor recommended
• variables should be kept until the final equation
• do not show trivial algebraic steps.
• give numerical results at the very end

• Describe the experiment you conducted to measure the performance
• use spring scales, masses, etc..
• Give the numerical result

• Calculate Factor of Safety (F.S.) in Force or Torque
• F.S. _Force = Force available / Force required
• Calculate and discuss the percentage error between the measured and theoretical maximum performance

• You should describe your assumptions in less than one sentence
• Indicate if the assumptions is conservative or optimistic
• Example: No energy losses due to friction (optimistic).

• Use an equation editor:  
• Microsoft word equation editor recommended
• Variables should be kept until the final equation
• Give numerical results at the very end
• Motion analysis of video can use Motion Analysis Software: http://physlets.org/tracker/.

• Briefly summarize the results of your analysis
• What did you learn from the analysis?
• Explain what you would do next time if you were to repeat the competition
• Conclude general and thoughts ideas for the robot.

Specific Guidelines and FAQ

• For MAE3 analysis, dynamics can often be neglected and quasi-static analysis performed.
• However, topics covered in lecture (e.g. friction and jamming in linear bearings) should not be neglected.
• Do not write out more significant digits than one has reasonable accuracy for.
• When describing assumptions, indicate if the assumptions is conservative or optimistic. With a conservative assumption, actual machine performance will be higher than predicted (the other way around for optimistic assumptions).
• There will always be differences between predicted performance and measured performance. The key is to get as close as possible with the analytical and measurement tools we have, and then make hypotheses to help explain actual machine performance.
• In MAE3 it can happen that one builds the machine without extensive use of analysis; instead relying on trial-and-error. In such cases the analysis is performed afterwards for the report. However, with real-world projects, typically trial-and-error is very expensive, so the analysis must be done before one builds. For the MAE3 analysis report, assume that you are doing the analysis before the device is built, and your objective is to determine if indeed the device will perform as required, and to predict performance speed and or force/torque.
• Some experimental measurements can be done to support the analysis, such as of friction in the system.
• What assumptions should I make?
• The analysis should only be as complex as it needs to be to generate useful predictions. All assumptions should be justified. The impact of these assumptions should be addressed in the discussion.
• Friction should not be neglected in linear sliders, since this was covered extensively in class. 

Example Analyses

• Robot Claw Analysis
• Raising the Hammer Example presented in lecture
• Car Velocity Analysis presented in lecture
• Car Pushing Force Analysis presented in lecture

• Car Acceleration Analysis