January 3, 2015
The first session of 2015 saw some important milestones: the prototype legs came together, and we did the first of the tests leading up to walking!
Thelonius worked on repurposing an old backpack, cutting off the main pouch so that the straps, frame, and hip belt could be attached to the armature:
Meanwhile, Cole and Gabriel started hooking up the pneumatic tubing and control boards:
With the straps bolted to the armature, it was time to start mounting the rest of the equipment:
Here’s where we ended today: everything for the legs connected to the armature with the armature held up by the support frame:
We were then ready to test if the left leg could be control by the wearer. The test was mildly successful in that the knee control worked pretty well, but the hip was very unstable because of overshoot. We think that will be addressed by refining the software to use proportional control. Right now the valves are either fully open or fully closed. By using pulse width modulation (PWM), we should be able to more finely control the speed of the cylinders and therefore hopefully avoiding overshoot. That will be a main task for next week.