Hi Delta and Peter N
I know you and your company have been essential in many fluid power (hydraulic) motion control projects. Can you please name a few of the most challenging projects Delta has been involved in when it comes to calculating and executing how to get all the “precision” in the motion control system? What first comes to my mind is the Bay Bridge in The Bay Area CA. What were the challenging issues developing lifting those super heavy concrete bridge span segments? I understand there were environmental challenges like wind, tides, and water currents but what more
Per Agesson, akkamaan
Per,
One of the most challenging was controlling an FAA runway test system. It is described here: FAA uses electrohydraulic controls for runway testing | Control Engineering
Another challenging one was a hay bale press: https://www.youtube.com/watch?v=_nbAgE7ugUU. You can’t see the pressing in the video, of course. The hydraulic cylinders had to give all the force they had and wait for the bale to compress, so there wasn’t any overhead for the normal control algorithms to work. Peter came up with a synchronized open loop algorithm that worked very well.
The San Francisco Bay bridge was rather simple from our end, though I am sure the larger project had many challenges.
Peter says hi! He is mostly retired, but shows up several times a week.
-Jacob
Thank You, Jacob. I will take a look at these two links. Say hi to Peter. Tell me I have resumed playing a little bit of table tennis. I quit when I was about 15 yo but started over in January and played till tennis courts were accessible after the snow period
Cheers
Per Agesson, akkamaan, huvva and yayamensun
I created a Delta RMC application that allows the customer to synchronize multiple adaptive sine wave type tests to multiple masters. Previously they had been using a single sine wave generator for each test.
These are hydraulic pressure tests running between 100-and 5000 psi at up to 8 Hz. When pressure builds, oil is required from the power unit. If multiple tests are running and all the pressure peaks come at the same time, the system runs out of oil. Previously, they had no way to synchronize and phase multiple tests. By allowing each test to be phase offset from a master, the peaks are spaced out and they can run more tests at the same time from the same hydraulic source.
This also takes advantage of adaptive control. Delta has sample adaptive control programs but all are for a single axis. Since this system can run up to 20 axes, I re-wrote the adaptive control program to be generic. All data is stored in arrays. This way there was only one program to write and debug.
I have to have a shout out to the excellent technical support at Delta Motionthat helped with this project. At one point they even made a firmware change for me to help keep multiple sine wave masters in sync. It’s now a part of the current firmware.
Also, pressure cycling at this rate is not possible without good design up front. These controls were retrofitted on existing hardware but whoever designed the rigs initially did their job right.