How does your team do basic layouts for manipulators or chassis and such. I dont mean exact drawings specifying bolts and such, just an early drawing to make sure all your components can fit and stuff like that. If you use a CAD program, which do you use?
Our team started out with just hand drawings and then later made CAD images in Inventor for some parts. We never made the whole thing in Inventor, however.
We made drawings and then modeled the robot out of cardboard. The advantages of cardboard are: it offers a life size mockup, is very easy to work with, and if you screw up, nobody cries!
We also did some CADing with inventor and plan to use that more next year as soon as we can get people trained.
We used Pro/Desktop from PTC for the students and I compiled all their designs into Pro/Engineer (also PTC). This gave us the ability to see most of our items would package. The problem with CAD is 3D programs can be memory hogs and it wasn’t long before I had to export smaller files for the students because their PCs couldn’t handle the files the way my workstation does.
I have to say though even as an engineer with a CAD system I live to use cardboard, wood, and PVC because nothing beats seeing the real size and relation of things.
We pretty much drew side, front, and top sketches of the basic components and lined up the parts or used scrap. We also measured out everything on the drawing to make sure everything fit right. We didn’t really get anything on Inventor because none of our members were trained with it at all, and we got the software in the middle of the six-weeks because of a shipping problem.
I used Inventor to do low resolution sketches for the initial design. So C-channels get modeled as square bars, motors might be just a cylinder slightly larger than actual size etc. The key here is to use the parameters to figure out the relative size of things then go back and do all of the detailed nuts and bolts.
I’ve started learning ProE, because we can get enough copies so everyone on the team can have one. Eventually we want to do everything in ProE.
We used pencil sketches, chalkboard and dry-erase board mostly. I used the Visio program that was included this year to do some fairly detailed 2-D layout work. It is relatively easy to use and very quick once you get the hang of it. They used to call it “the drawing program for the rest of us” or something to that effect. I highly recommend it. It is pretty easy to create objects (motors, bearings, wheels) and scoot them all around to see where things fit.
I do wish they had included the professional version with all the engineering, software design and electrical templates. Still, you can create your own templates, which I’ve found useful over the years.
what do you mean design…
The Miracle Workerz have a few days in which we all come together and brainstorm. Once we decide a basic strategy, each student is required to submit at least one way at accomplishing our strategy. Everything from manipulators to chassis to drivetrain is normally covered by the end of this session. Once we have completed these initial designs, we vote on which we think will be the most efficient at accomplishing our strategy. Once these are complete, a basic robot is modeled in Pro-E for the main robot layout. Solidworks can be used from time to time, as it is more readily available for students to use in their own homes though.
We used Rhino 3d to do all of our concept drawings, i can draw things relatively fast and with some accuaracy and scale so it works well, The first one i did took me about an hour and then that one kept being changed
Maybe I should take some lessons from you. Here at work they scrapped Correl Draw and gave us Visio with no warning and no training. ( “Here’s your new upgraded computer sir. All loaded with the latest standard software package. No sir, I’m afraid you’ll have to learn this new stuff” ) As far as I’m concerned it MIGHT be good for flow charts and org charts, but since I never do those it’s useless to me. I still can’t figure out how to do an irregular polygon …
I must be missing something that’s supposed to be obvious, but isn’t.
ChrisH
Use the straight line tool to click, drag, release in succession for each side. Just like connecting the dots. The last line should have the endpoint aligned over the starting point before being released and the wire frame will become a solid. You could also probably just stick a bunch of individual lines together if the sides need to be of precise length. There’s a pop-up box available with some dimensions and you can alter them rather than eyeballing and dragging (I forget which menu bar option has this…they moved it in Visio 2003).
Alternatively, use a stock shape with the correct number of sides, select it with the straight line tool (click and release), select a vertex (which will change color) and you can then drag and reposition it. Also use this technique to correct any shape you draw.
Check out the Union, Combine and Fragment features for working with two shapes. Pretty interesting.