i have noticed that the usual catapults used in these experiments have a large concave cup. i think it should be a flat stand with the ball resting on the beam... this assures that the ball is always on the same spot and not rolling on the concave curvature of the prior design as it exits the propulsion mechanism?????
Thanks for your question. I agree that the concave cups definitely are not a good solution for a precision catapult. In the case of a flat stand: how to ensure that the ball does not roll from the flat stand while the arm is accelerating? Another flat stand in the vertical direction? So the ball is in contact with two (more or less) perpendicular planes? Then, the ball can still roll along these two planes. This means that we need another plane, (at least somewhat) perpendicular to the other two. So a total of three planes are in contact with the ball. Then, all three translations of the ball are fixed and we have minimal friction when the ball is leaving the catapult.
Marc - I like your racing car example at the start of the video but have you got the racing teams interested in DOE? drop me a line on paul.allen@allenp.co.uk
Thank you for your comment and great job. You might like to check out our students in this video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-sJ2USsFOcZM.html We threw dice to specify a shooting distance. At the 44 second mark in the video you can watch how the students used their DOE results to set up their catapult and shoot a series of 6 balls in a 10cm by 10cm box at the specified distance.
Perfect explanation, the best so far in RU-vid, I will use it for my 6Sigma trainings. Thank you very much! My questions: 1) Why the slope on the system hardware to get a better curve of the shots? To get the parts into the basket? 2) In base of what judgment was the selection of the fix factors and why you decide not to analyse them? For example the ball cup height or band routing? 3) How was the selection of factor levels? Just testing to see the maximum and minimum achievable results (0-300cms)? In the reality that cost money. I would like to understand why not cero could be a good operating window? 4) Why the not the use of replicates in the DOE? Is there a reason why just 16 runs without replication? 5) Does measurement system (in this case, the person telling the results) was confirmed before the experiment? Thank you once again, best regards.
Thank you for your questions! 1) Or else you cannot get a variation in the height of flight which is intuitively important. 2) In this example it was engineering judgment basically 3) It might. This is the simplest instruction video we could think of. 4) see previous answer. 5) no, also same reason
