THIS BLOG HAS MOVED TO YOUTUBE!
|MSP430 and flow meter for actuator positioning.|
Progress on the hydraulic bartending robot!
I was doubtful that a ten dollar plastic flow meter would allow us to get within a half mile repeatability for cylinder positioning.
After a few stumbles with solenoid voltage spikes, sticky turbines and noisy compressors; initial shop testing proves that we can easily achieve 5mm accuracy on a 2000mm stroke.
The initial run cycled to a pre-set 457mm stroke length every 5 seconds. The actual strokes were bell curve distribution from 454 to 460 with the mean spot on 457mm.
The test ran for about 30 minutes (360 cycles) before the flow meter crapped out.
The 43oh didn't get a pulse count from the flow meter, so it kept the air solenoid valve open. The piston slammed up against the gland at full speed; scared the ever livin shit out of me! I'm not sure why the flow meter seized up, but nothing a little disassembly and percussive adjustment couldn't fix.
Prior to getting the test running, I had troubles with the Dangerous Prototypes ATX breakout. Every time a solenoid would de-energize the ATX would shut down. With the help of the Dangerous Prototypes forum members I stumbled upon my rookie mistake: installing snubber diodes too far from the solenoids.
|Relay Board, Adafruit flow meter and 43oh|
Watch the YT for more cylinder choochin' fun!