Konstruktion 8
− Frauenkirche-Turmuhr-Modell
Sommersemester 2007
Project description:
The old clockworks that were installed in the clocktowers of the Frauenkirche were taken out of the towers in the 1960s and have been sitting in the basement at the Deutsches Museum until now. The museum wants to renovate these clockworks after documenting exactly what they have. But even after they’re renovated, they won’t run. Rather this will be a static display.
They want to produce a solid model of the works, that can be used to make a computer animation. This will sit beside the works and show viewers how the pieces work to mark time.
To make the solid model, we are going to use SolidWorks. The FHM has SolidWorks on computers in the R building. It is used in Electrical Engineering. We are getting student versions of SolidWorks for the team members.
So far, I have visited the museum and viewed the works. We actually measured some pieces, and I made solid models of them. The project will involve working closely with museum personnel to take measurements. Then turning those measurements into models of parts. We can’t just randomly approach this either. We need to approach it logically, produce models of the important parts first, then make an animation of these parts. Just the organization of how we divide the parts of the clock up and how we make part models, sub-assemblies, and assemblies will be challenging. It's also self-important just to document our work. So clean, easily readable calculations (probably in Excel) will record our analysis. As a project building block I envision a SolidWorks part with an accompanying spreadsheet that clearly shows how the part was modeled. More on this below.
This is a huge reverse engineering project. But it has a twist. The object of interest is very old and has been renovated and modified over the years. For example if you were going model a gear nowadays, you would take some specific measurements (pitch diameter, number of teeth, etc.), assume you had a specific kind of gear (cycloidal, involute, etc.), read up on the design procedure for this type of gear, then model the gear. In this case, however, one cannot be sure that the procedure used to design the gear was standard procedure. Back when this clockwork was designed (in the 1840s), there were no standards. So one has to dig deeper and see if a part actually complies with what became standard practice after these parts were designed and built. So there is an element of historical mystery in this too.
The project's execution method is something we will discover as we are going along. What we do, how we do things…all this needs to be worked out. An example: I was working with a master clock mechanic at the museum. We were making measurements together, but actually he was making the measurements and calling them out to me. He could measure faster than I could write. So even though I got useful information, my notes in my notebook were not as neat and orderly as I wish they could have been. Then I came home and had to struggle with these notes to get out of them the information I needed to model a rope drum and a chain sprocket. In doing this, I made many calculations. I wound up doing these in Excel and doing them orderly in Excel, because I have done this many times and have seen the advantage of recording calculations in formulas in a spreadsheet. This will also be useful to the museum curators in the future, because it documents exactly what calculations were done as part of the reverse engineering. So our job is not just somehow to produce a solid model of the clockworks and leave behind a bunch of messy, disorganized calculations to illustrate our work. We have to proceed methodically and leave behind a “checkable” trail of calculations that makes sense to someone who looks at them years from now. In other words we are also ourselves creating a historical paper trail that documents how we think the clockmaker designed this clock.
Like all design projects, part of the requirements for the project is that a report documenting the work is written and delivered. Students will also deliver a presentation to describe the work.
Project sub-teams are organized around sub-assemblies of the clockworks. Sub-teams will measure individual parts, perform reverse engineering calculations on them, and then model them as parts that are compatible with the parts modeled by other sub-teams.
Though solid modeling lends itself very well to reverse engineering, its application in the field of historical, technological investigation is relatively new. Museum personnel are also interested in this field and interested in acquiring solid modeling skills as the project is carried out. Students will be involved in working with Museum personnel in a technology-transfer assistance role.
This project has is a public-service project too in that the student team is helping to preserve a piece of Munich history for Munich's citizens. As such it plays a beneficial public-relations role for the FHM.
The team consists of American, Finnish, and German students.
Beschreibung des Projekts:
Die Turmuhr der Münchner Frauenkirche, von Johann Mannhardt entworfen und hergestellt, war von etwa 1850-1960 in Betrieb. Seitdem wird sie im Keller des Deutschen Museums gelagert un betreut. Das Museum hat vor, the Uhr zu renovieren und der Öffentlichkeit zu präsentieren. Sie wird jedoch nich gehen. Um dem Betrachter das funktionierende Uhrwerk zu demonstrieren, soll ein "Solid Model" der Uhr auf einem Rechner alle Funktionene zeigen. Das Museum hat die Fachhochschule München (FHM) gebeten, das solide Modell mit Hilfe der Studenten zu bauen. Die FHM-Fakultät-03 (Maschinenbau/Fahr- und Flugzeugtechnik) hat das Projekt im Sommersemester 2007 aufgenommen.
SolidWorks, Inc., Hersteller von SolidWorks, eine Software für den Bau von soliden Modellen gedacht, hat nicht-gewerbliche Versionen der Software dem Museum und den beteiligten Studenten geschenkt. Ein weiteres Ziel des Projekts ist die Beherrschung dieser Software eigenen Museumangestellten zu vermitteln.
Das FHM-Team besteht aus 7-9 Studenten. Sie teilen die Arbeit der Modellierung des Werks nach der internen Struktur der Uhr auf. Die Studenten messen die zerlegten Teile, leisten Reverse-Engineering-Berechnungen, dokumentieren diese und bauden das 3D-CAD-Modell. Aus diesem Grund arbeiten sie sehr eng mit den Renovierungsfachkräften des Museums zusammen. Am Ende dieses Semesters schreiben sie einen Projektbericht und halten ein entsprechendes Referat.
Interessanterweise ist das Projektteam international. Es besteht aus einigen kalifornischen Studenten, drei finnischen Stuenten und einem oder zwei Deutschen. Der Beauftragte ist Dr-Ing Frank Owen, ein Gastprofessor der California Polytechnic State University. Er ist erreichbar unter fowen@calpoly.edu.