Slow Progress
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| Proportional valve and pot.drawing |
I got
distracted by several projects that needed doing and then it got cold and too
rainy to work outside. I worked on the project a little in November and decided
that those servo follower valves had to go; they were still too jittery. I am
trying servo driven proportional valves to fill and empty the pistons with air
under the direction of the Arduino. It is going to make the programming more
complex but I think I can smooth out the leg movements this way.
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| Proportional valve and pot.photo |
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| Leg speeds at 60 PSI |
I am
using linear 10K slide potentiometers to keep track of the knee position in
real time. A voltage near zero is produced when the leg is retracted and a
voltage near 5 volts when it is extended. This increased the number of analog
inputs in the project to eight, so I upgraded to an Arduino Mega. I ended up
using the Arduino Uno in a keyless entry project anyway. I was able to make graphs of how fast the leg moves at different servo positions by sending Arduino telemetry to the monitor screen while executing a test program.
I
reworked the hip sensors so that the telemetry from each leg is consistent. The
right rotation sensor gave values that behaved oppositely to the left rotation
sensor values. Now rotation values increase as either leg rotates backward at
the hip.
