Subject Code/Name: MEC2402 - Engineering Design I Workload: 2*1 hr Lectures (Workshops), 3 hr Comp Lab, 2 hr Tutorial
Assessment: Note: This changes year to year.
- Online quizzes before each Lecture: 8%
- Worksheets each lecture: 8%
- Weekly CAD Tasks (x8): 8%
- CAD Exam: 6%
- Warman Prelim Submission: 10%
- Warman Competition Results: 12%
- Warman Final Submission: 18 %
- Exam: 30%
Recorded Lectures: Yes, with screen capture
Past exams available: Yes, Most exams bar one back to 2006, only the last year or two were indicative of the actual exam.
Textbook Recommendation: 1. Field, B. Introduction to Engineering Design (any edition)
2. SAA/Inst of Engineers, Australia: Engineering Drawing Handbook, SAA HB7, 1993.
The former is a must have, you'll use it a lot, the latter you'll use too but not as much.
You can bring both into the exam with you so they're worth getting .
Lecturer(s): Scott Wordley
Year & Semester of completion: Semester 1 2014
Rating: 4.5 out of 5
Your Mark/Grade: Pending
Comments: There are a lot of aspects to Design I which I'll try and go over individually, but in short Design I will take most of your time throughout the semester, it's a workload heavy unit (especially the Warman Competition), but you gain a lot of experience and get a lot out of it.
Flipped Classroom Model I'll start off with the way lectures were run. This year was the first year that the Engineering Faculty have tried the flipped classroom model, and it make be used for other units in the future if they think it was beneficial this semester. Basically, there are small videos put up before each lecture, ranging from 10 minutes to say about 40 minutes, which you watch and learn about the content and theory side of things. Before the lecture, which is now called a Workshop, you would then complete an online quiz about the videos, they're quite easy and are there to make sure you've watched the videos beforehand. Then in the Workshop (lecture), you come in and as a lecture and/or with your Warman Competition group (more on that later), you work through the worksheet, getting tips and help from the lecturer and tutors at the same time. These are then marked in the tutorial the week later. Overall, I think this was a good way to go, at least for design. It's one of those units where the lectures would be quite dry if it were run like a normal unit, but having the workshops allowed you to put into practice and try things out, while having the lecturers and tutors there to guide you along. It seems to fit the unit particularly well.
THE WARMAN COMPETITION This really does deserve the capitals above. It will really take up a lot of your time and effort outside of uni. The Warman Design and Build competition is a competition in which teams from across the country design and build a robot like device to navigate a certain course and achieve certain goals. The track and objective changes year to year, and for design a campus competition is run just for the unit. The winners of the competition go on to represent Monash at the National Finals.
This year, we didn't get to pick our teams. Normally it's in teams of, but the difficulty of the competition was ramped up this year, as most teams found it too easy to navigate the course at the national finals. As a result for the campus competition, we had teams of 8, but unlike most years had to build two devices. To give you an idea of what kinds of things you'll have to do, here is the National Competition from the year before:
VIDEO
There are three stages to the competition, the Preliminary submission in which you create a design and work out what goals you want to achieve, along with some drawing, the actual competition where you are judged on your runs, and the final submission which mostly includes engineering drawings done through CAD.
For our year, we had to transport "e-waste", which was a payload of rice, the mass of which we nominated (minimum 200g), around a barrier and then over a bar at a set height, which again we nominated (in 10 cm increments, maximum being 120 cm). The design brief for your year will be along the same format as ours:
http://www.ncedaust.org/ckfinder/userfiles/files/Warman%2014%20v1_1_1.pdf The scoring formula was fairly complicated (under R45) and it set teams on two paths to maximise their score. You could either go for maximising the height with the minimum payload mass or maximising the mass with the smallest height. This was a design decision that had to be made early, with most teams going for the former option, which would include a lifting mechanism and somehow counterbalancing it, keeping in mind that the larger the mass of the system, the more your score decreased. So as with engineering, it was a balancing act, making compromises. Our team initially went for a height based system, attempted to go over the largest height of 120 cm. I should also note, as with most years, there is a limit on the size of your device, most years it has to fit in a 40x40x40cm cube. We had to have two devices, one had to be purely mechanical, no batteries, no electronics, no nothing. The device that started had to start in the 40cm cubic envelope and could finish at whatever size while the device that finished could start as large as it wanted to but had to fit in the 40cm cube at the end of the run. This meant there had to be a large extension compared to the base size, and ultimately meant a lot of devices were unstable at high heights.
A lot of teams, as did we, went for a scissor lifting mechanism, some went for a telescoping air system to lift the mass, while others didn't lift at all, but put a large mass over the 30 cm bar. We had to CAD up our initial design, and if your design is the same as your initial design by the time the competition comes around, then you're doing something wrong. There will be a lot of changes in the design process, as you realise certain things just won't work, or that you won't be able to put certain parts together since you may have not allowed for access to screw something up.
You and your team will have to fund the build and all the materials for the competition . Most years teams get away with $100-$400, since our year was a bit more complicated, we set our budget at $400 initially, which was $50 per person. By the end of the competition we had spent close to $800, and a fair few other teams had too. We weren't the highest spending team, with one hitting close to $1200 (a lot of that in burnt chips, but I'll get to that later). You'll ending up making a lot of trips to Bunnings and/or Masters, throughout the competition we would have racked up a fair few laps around the places. You don't get a workshop for the competition either, so you need to make use of the limited tools you have, which restricts what you can do a fair bit. WD-40 and Duck tape will be your best friend though!
For the first time, we were provided with "Arduino kits", which were basically electronics kits with an Arduino controller (the brain of your robot), a motor controller (since the arduino can't handle the current or voltage needed to drive any decent motors, the one provided matched with the rover that was purchased), a voltmeter and an assortment of wires and other things. At the end of the semester you have to return this kit, and anything that you break or damage you will have to pay for. This is partly the reason one team spent so much, they blew up or so chips, which at $20-40 each starts adding up. The coding for the arduino takes a bit of getting used to at first, but isn't too bad.
The Arduino with the motor controller in the backgroung, connected to the rover.
Keeping within the rules of the competition, you have to either buy parts or make them from scratch without professional help. Most teams bought a rover chassis for their electronic device:
http://www.pololu.com/product/1551 The teams who didn't had a lot of trouble getting their device to go in a straight line, you need that consistency in your runs. The rover chassis helped with this, and since it has encoders (something that reads the wheel rotation and sends it back to the arduino chip), you can control how far you want it to go via the number of wheel rotations. Without this you can only set it to power the wheels for a certain amount of time, and as your batteries drain down this changes every run, you end up chasing your own tail and never reaching it. Also, rechargeable batteries are a good idea, we did buy some but had a problem with the connections and as a result didn't end up using them. Another team used mecanum wheels, which would allow them to drive sideways, in practice it didn't quite go completely sideways, which is why you shouldn't expect everything to work as you would think it will.
The one main thing idea for the Warman Competition is to
start early , I cannot stress this enough. If you can, order locally. We had ordered specific motors which had to come from Perth, the first time they sent the wrong motors and we had to get them to resend them, which put us back a week. The second time we received one of the correct motors and one of the wrong motors, which put us back another week. At this stage it was too late to change the coupling mechanism and we couldn't adapt motors from Jaycar locally. As a result this meant despite spending a lot of money on scissors lifts and getting them to work well, we had to redesign the whole device to move from a height-based system to a mass based-system the day before our competition. This meant that our device was not optimised, and was a lot minute job to bring it all together. We worked on it, rebuilding it from 10am in the morning to about 8-9 pm, with minimal breaks.
There is a track in the Engineering Building to test on, the earlier you get onto it, the better. We were one of the first few teams testing, and at our first and second tests the only team on the track at the time. As a result we got a lot done, didn't have to wait for other teams to have a go. In the week or two leading up to the competition, the track will get insanely busy, imaging around 10 teams (there was about 28 in our year) trying to get their testing done on the same track at the same time. Sometimes you could be waiting up to 30 minutes between runs, just to make minor adjustments. The night before the competition, don't be surprised if you have to pull an all nighter and work your ass off at the last minute. A few from my team were there, testing for about 4 hours, at around 2am my laptop battery died. We had forgotten that the code doesn't save to the arduino when you upload it, so we lost those 4 hours of code and testing.
So make sure you save the damn code regularly! At that point the others gave up and went home. If we had left it in that situation, then our team would have gotten zero for the runs. I stayed there working on our device on my own throughout the night and early morning, along with 4-5 other teams pulling the all nighter as well (being up that long with no sleep you make a few new friends :P) Since we didn't know if our device B would be functional at the time or not, we lowered our goals and just got device A set up to transfer the payload without turning. In the end I broke my record of hours staying awake straight, 32 hours straight, with 30 of those being at uni. It's quite weird to see the sun rise through the windows at the end of the engineering building.
During the competition you get two runs, the score system dependent on the runs changes each year. For us it was meant to be your best run plus half the other run, but ended up just being the score from your best run. Our first run went well, and our second had a bit of a problem and ended up being a zero run score. A lot of teams that were going for the 120 cm bar, had achieved it in practice and got it on video, but ended up with two zero run scores on the day, (one device did really well, but drove off the end of the track). You either seemed to score really high or get a zero (or close to it). The second run, teams improved a bit, and since there was a lot of zero, they decided to be lenient on the scoring and give some of the score for the run in certain cases. This was only due to the difficulty of our competition this year. This again, is where consistency comes into play, you need to be able to reproduce the results on he day when it matters (much like the real world I guess, in Motorsport there's no point in being fastest on a test day if you can't pull it off on raceday). We ended up being ranked right in the middle of the pack, there were a few teams that made it to the end zone.
We initially got 2.8/10, but had our score bumped up to 8/10 due to the issues we encountered and what we showed would have been possible. Normally this doesn't happen, but since a lot of teams put a hell of a lot of effort into the comp and then got some low scores, they allowed us to do this for this year. Don't expect it to happen every year. We also had to keep a moodle log of the project, to show who was contributing and have ideas floating around. A lot of people spoke on fb, which you would then have to copy the conversations over to moodle. They may change the way this is done next year. There is also a peer-assessment component to the whole project, where you rate group members on what they contributed. This is then used to scale the marks of team members, where you can get anywhere from a 0.3 to a 1.1. It's a good idea, but you will still get some slack team members who don't care about the grade they get.
After all of this you will then have to do a big report on the competition, and use some of the CAD of your device to make proper engineering detailed drawings and assembly drawings. This has an individual component and a group work component. Try not to leave this to the last minute either. The submission was due at 1am, but we encountered problems with the computers in the Engineering Comp Labs, and so weren't ready at that time. We ended up going back to one of our team members house at 2am to use his computer (since it could handle just about anything), didn't get home until 4.30 am that morning. You get to make use of the New Horizons building computer labs for the tutorials, we were unlucky, being one of two teams that couldn't fit and so had to do our tutes in the computer lab, (more on the CAD sides of things later).
I should also point out,
if you join the FSAE team (Monash Motorsports) or the UAS team (http://www.monashuas.org/ - Builds autonomous planes) then you won't have to do the Warman Competition, but will have your work based around what you do in those teams. They're good teams to join, Monash Motorsports is currently ranked 2nd worldwide (they were first a few months ago!), while the UAS team do a lot more of the aero side of things. I know a fair few mates in UAS, and they do learn a lot more through the team.
Overall, you do learn a hell of a lot from the Warman Competition, but have to sacrifice a lot of energy, time (and money) for it.
CAD and Solidworks Through the tutes, you learn a bit about using the CAD (Computer Aided Design) program Solidworks, basically making parts and assemblies in a 3d computer environment. You can get a student copy of Solidworks through Monash, which you will be told how to do at the start of the semester. It really is a useful tool, allows you to see some problems before you make the part, which ultimately saves time and money. It simplifies doing engineering drawings, once you have the part cadded up it is a few clicks here and there. I really enjoyed working with Solidworks, but it can have a step learning curve at times. It also takes a decent amount of computing power to run mid-large parts and assemblies. At times the Engineering Computer Lab computers may crash on you or lag like there's no tomorrow (and they're not that bad computers). The computers in the New-Horizons design labs are a lot faster, it may take 30-60 seconds to load Solidworks in the comp labs, where as the New Horizons labs takes about 2-3 seconds.
Towards the end of the semester you'll sit a 3 hr CSWA CAD Exam, which is a computer test designed to see how well you can use Solidworks. You're given a few drawings of parts or assemblies and then have to make them, then you're asked something about the part which you have. So like what is the center of mass or the moment of inertia around a particular axis, which you get from the tools in Solidworks. If you're made the part right you should get the right answer, otherwise it'll be completely off. You need 70% to pass the exam, worth 6% of the unit. A fair few people were getting around 65-69%, from memory we had around 1-4 fail. At the end of it if you do pass you get a CSWA certification which you can put on your resume.
E.g. One of the CAD Tasks we had to do
Exam For us, the in semester work was worth 70%, so the majority of us had passed before we had even sat the exam (it's a nice feeling). The proportional of marks changes each year, but it should be around there. The Exam will be mostly on Detailed Drawings, Assembly Drawings to the Australian Standard AS1100, Casting and Manufacturing Methods. If anything, Detailed drawings will be the most important topic for the exam, so make sure you learn that properly. While it's quite easy to get some marks on these, it's really easy to lose marks on them as well. Small, simple things that you overlook will cost you marks, not putting a border around the drawing, not including the projection system in the Title Block, over-dimensioning the drawing or using too many views to represent something that can be done in less views. You'll need to know how to do this later in industry though, so it's good practice.
EDIT: I'll put the images in spoilers to make the post not as long