Friday, October 11, 2013

Last weekend (I know it was a while ago, just forgot to post), we worked on making the elbow joint for the arm. This would be where the potentiometer lies to read the A/D values and determine position of the arm. The material used was delrin mainly because it's easy to machine and because it's anti-friction so it makes for a good moving joint. The part was CNCed and the pot was mounted with JB Weld epoxy. I wrote a short Arduino program to measure the A/D value of the pot to center it in the joint. We drilled holes at the ends of the joint to insert threaded rod to connect to the rest of our mounting hardware. Here is a picture of the joint clamped together while it dries:
Next we will designing the rest of it in hopes of getting some sort of working demo before our presentation Friday.

Monday, September 30, 2013

We recently had another meeting trying to get the TI Code Composer Studio. We ended up only getting it working on Windows because of TI's lack of support for Linux. However, after spending nearly 2 hours trying to get an example project to build and even connect to the board, we decided that it might be a better idea to just use an Arduino to prototype before we waste anymore time. As for sensors, I was thinking instead of having a sleeve (because it can move) it would be better just to create an exoskeleton brace and have a mounting point for a potentiometer on the elbow joint. Then we can build off of that.

Friday, September 20, 2013

Welcome! This blog will contain the life and times of Project Bear Arms, an open source design for strength increasing robotic arm. 

After doing some independent research, Bharath Santosh and I (Eric Oswald) finally sat had our first official meeting. Basically I bought a DSP that would work perfectly for controlling the arm. We needed something that was real-time with a decent amount of hardware interrupts. The TI C2000 fit our specs very well. I bought the Launchpad for it because it was on sale for a good price so that's what we will be using as of now. However, upon installing the Code Composer Studio for the chip, we both ran into troubles. So as of now, neither of has gotten the TI software to work.

As far as the control system goes, we started discussing the types of sensors we will need to use to make sure this thing is safe. Since we are only focusing on one degree of freedom (the elbow) for this semester, we are thinking of just using a pot on the mechanical joint attached to the elbow as well as add flex and stretch sensors to a sleeve the user would wear under the arm itself. Something like an Under Armour sleeve perhaps.

Nick Avila wasn't able to show to the first meeting so we did't go into great detail on the mechanical system but since I am going to Maker Faire tomorrow, I thought I would talk to some of the makers that specialize in robotics and prosthetics and gain some insight.