Hey all! So It's been a *long* time since I updated this thread... Been wicked busy finishing up school, participating in the MATE competition and so on and so forth. I got rejected as a transfer to Carnegie Mellon University (my dream school...*sigh*), but was accepted as at Worcester Polytechnic Institute(yes! :-) ). I'm double majoring in computer science and robotics engineering there.
So I will finally be able to take classes specific to robotics- I don't know if you have any idea how much that excites me!
Anyway, I did manage to get Ally walking about, and I have videos. I'll get those posted later tonight when I have a decent internet connection. However I have quickly realized that there are several design flaws in her chassis and hardware. These are:
-Chassis Flex: The one sheet of poly I used for her main chassis allows for too much flex. I have tried reinforcing the major flex points, which helped alleviate the problem to a certain extent, but it still is noticeable when she walks; especially in a tripod gate
-Unbalanced Payload: Her weight distributing is "all-kinds-of-funky" (according to my friend). This contributes to the flex problem mentioned above. Also, her battery is a tight fit underneath the chassis- especially when she gets to walking.
-Mechanical Restraints: Her legs are spaced at uneven (though bilaterally symmetrical) points along her chassis. this means that each leg has a radically different range of motion from the others.
-R/F Interference: I discovered this one by accident. I took Ally to one of my school's labs to show her off, and could barely get a signal from her wireless security camera. It took a minute to track down the problem, but we narrowed it down to the vast amount of cell-phones, laptops, and a wireless access node inside the lab all transmitting at once (this is what you get when you pack a room full of geeks I suppose). This might be a one time fluke and there may be no way around it, but I figured it was important enough to list here.
So here is my to-do list:
-Redesign her chassis
-Find a smaller battery pack
-Investigate options for a new wireless camera system
For rebuilding the chassis I haven't given up on polycarbonate entirely just yet. I may try two pieces of poly: an upper "deck" and lower "deck." For the supports/struts between the two decks I have been playing around with the idea of using balsa wood for its strength to weight ratio. I will also explore the option of aluminum, although I am still lacking a decent shop to work it in.
Right now, I am using a 6 volt NiMH 1600 mAH battery pack to supply power to her servos (this one here: http://www.lynxmotion.com/Product.aspx?productID=331&CategoryID=48
). This is turning out to be far bulkier than I would like. Any suggestions for a better option? :-)
For the wireless camera I am looking into something like a WiFi enabled webcam... the wireless security camera I have right now is nice because of its size. I may not need to replace it, but if there is a comparable option out there that doesn't require the use of a video capture cable I will consider it.
I guess that's it for my update! I'll have those videos up later. I also promised a while back to post source code at some point- I need to clean it up and comment it better before I do that- right now it's such a mess that it's embarrassing! :-P