Megan's Course Project
My goal is to create a physcial and virtual biobot with four legs that walks. This biobot will be low to the ground with big feet to make balancing easy. It will walk by having opposite legs moving in the forward direction at the same time.
The biobot was created with the idea of carrying a handyboard on top of it. Due to this it has a wide short body. It has four legs which were orginally made with bricks and beams. Now they use 'arms' (i like to call them rods) with tires on the end. I put tires on the end once I saw how much the legos slid on the desk top. The tires added a lot more friction and solved this problem - it will be interesting to see if the bot walks on carpet. Each set of legs will be powered by a motor (I believe it may be hard to start the motors are the same time since we are not using the handyboards.)
http://i35.photobucket.com/albums/d170/bestisyettocome3/Drexel/DSC01302.jpg http://i35.photobucket.com/albums/d170/bestisyettocome3/Drexel/DSC01306.jpg http://i35.photobucket.com/albums/d170/bestisyettocome3/Drexel/DSC01307.jpg http://i35.photobucket.com/albums/d170/bestisyettocome3/Drexel/DSC01308.jpg
Original Concept: I have decided to model my robot after the nara cricket, the link below is a video of it walking. I choose this bug mainly because I wanted to use a 6 legged insect. From my searches it seems that many different bio-inspired lego robots have been modeled after insects.
I have been trying to build a six-legged robot and it is getting pretty large, so I may decide to knock it down to four legs. I orginially wanted to use six legs because I thought it would be easier to balance when walking, but now I hope I can manage to do that with just four legs.
Also, I found a researched lego motors since my kit did not have any. I found a site (link below) with different motors including the one that is in our kit. This site just tells you about them, but I have also found places to purchase some of them (ranging from $20-30.) If anyone needs motors (or has extra motors) please let me know so we can figure out if we need to place an order asap.
This week I worked more on the physcial model. It is complete except for the parts that I don't have. I obtained a second motor and have sent out emails to see if people have the parts I need. Specifically, I need the lego peices with the wires so that I can connect my motors to the batteries.
I also spent time play with IDEAS what I have figured out so far:
Open the IDEAS 12 program
The model path should be F:\scratch\LegoPartsLibr.mf1, Click OK
Click OK twice, then dismiss
Save As something else before you make any chanages - there will not be enough room on the F drive so you will have to change the location. It is probably best to bring your own storage.
Click on the down arrow next to the Manage Bins icon (two red triangles on opposite corners with square in the middle) and select Get This will bring you to a list of the part, click the one you want and hit OK (will close the window) or Apply (adds the part but does not close the window)
When you add a part it will be removed from the list; if you do not want it any longer you can "put it away", do not delete it
The F keys allow you to change your view (hold them and move the mouse)
F1 – translate
F2 – zoom
F3 – rotation
All the items will come up in the middle of the screen to move them Click the move icon (two squares representing a translation) and follow the prompts in the lower right corner - more detail below.
- Select the part (left click)
- Right Click the part and go to done – a window will pop up
- If you select Move To you have to select another part to move it to
- If you select Slide on screen, you can click and drag it to another location on the screen
- If you select copy sw you can make copies – enter the number of copies you want and then click and drag
I have not been able to get two pieces to connect to each other even when trying to use the move align options.
I completed building my physcial robot, but have not been able to test it. I plan to get the wires I need to hook the motors up to the batteries in class today. I also played with IDEAs more, but have not actually started building my virtual model. I am going to explore more tutorials before next week so that I can start to create my viruttal model.
I read through some IDEAs tutorials. I am able to follow the tutorial to a certain point, but then the steps do not seem to make sense. I am not sure if they have changed the UI with the different versions, but the buttons it refreneces are not there. I want to look at other tutorials and play around with this more to see if I can mate two lego pieces.
This week I was unable to make any progress. I believe I found the sequence of step to mate two lego pieces with IDEAs. However, IDEAs continues to be unstable. It consistantly crashes every time I attempt to make a joint. Since I could do little work there I typed up the notes from the lectures for this week.
I may have to switch to Adams or another tool at this point :/
http://i35.photobucket.com/albums/d170/bestisyettocome3/Drexel/DSC01239.jpg http://i35.photobucket.com/albums/d170/bestisyettocome3/Drexel/DSC01240.jpg http://i35.photobucket.com/albums/d170/bestisyettocome3/Drexel/DSC01241.jpg
This week I finally made some progress. I borrowed a set of wires so I can now power one of the two motors. This allows the bio-bot the walk without me hand-cranking it. The robot often falls apart, I believe it is because the motor spins so fast (it may also be because both motors aren't running.) I am going to either add more legos to the sturcture for support or connect it to a handyboard so that I can control the amount of power that is sent to the motor. I also thought it would be interesting to build a virtual model just like the current physical model and see if it would break at the same points.
As far as my virtual model goes, I have completely given up on IDEAs. I know I said this last week when it kept crashing, but I thought that it might actually work in the MEM lab. I spent some time with it there after Michael setup an account for me and got the license issues corrected; however, it would crash at the same point. Now I am going to use Solid Works to build my assembly. I have tested it out this week and have already gotten further than I ever did in IDEAs. I had two lego pieces and added contrainst to make a joint. I am going to continue working on this next week.
This week I redesigned my physical model. I was unable to find two sets of wires. Since I could not power both motors at once, I took one out. I also added more legos to the sides which will keep the frame body from falling apart when it walks.
I have switched to Solid Works instead of IDEAs and things are going much better. I have saved the lego pieces that I need into solidwork parts and added them to some assemblies. I built the leg and the frame pieces that hold the legs in place.
I built the virtual main body frame this week in Solid Works.
On Tuesday I met with Dr. Regli for a progress report.
And then Thanksgiving :)
The following media clips are available in two formats. the were generated using Camtasia 3.0. The Windows Media files play more smoothly than the .avi for some reason.
This clip shows the simulation in SolidWorks:
This clip shows the virtual model from all views: