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Dean
On my boat, the original hydraulic system had an on demand Monarch hydraulic power unit that supplied pressure at about 2200 psig to five hydraulic functions, four of which were small hydraulic cylinders for control surfaces and the drop weight and one hydraulic motor connected to a lead screw that moves a 100 lb trim weight for longitudinal trim. All fly by wire through a joy stick connected to my PLC. I used electrohydraulic cartridge valves for pressure and flow control from www.hydraforce.com Lessons learned. All systems worked as designed but the HPU I was using was very noisy and consumed way to much power. Both bad for a small electric psub. I am currently installing version two of my hydraulic system. I have dumped the central HPU and cartridge valves I am now using four small quite independent pumps/motors that are used on sail boats for autopilot http://www.accu-steer.com/HRPSeries.html These pumps put up about 1100 psig and coan run on 12 or 24 vdc. I have connected one of these small pumps for each control function i.e., yaw, roll, pitch and trim hydraulic cylinders/motors. The speed of these small hydraulic pump/motors is controlled by PWM driver cards http://www.dimensionengineering.com/Sabertooth2X25.htm. Each of these cards control two pump/motors so I have two. My dual axis joy stick sends a 0-5vdc signal to PLC for pitch and roll movement. My rudder pedals are connected to a pot that is connected to the PLC. The PLC has a analog input module to receive these control signals. The PLC also has a Analog output module that sends the 0-5 vdc output signals to the pump/motors where 0 vdc is full speed !
one dire
ction, 5 vdc is full speed in the opposite direction and 2.5 vdc is full stop. When I get the boat back in the water, I will see how new hydraulic system works but just from bench testing, I can see that the new system pulls way less power and is very quite. The nice part about running the control functions through a PLC is that it is easy to setup an autopilot system in the future that will hold the boat heading / depth / speed.
From: Recon1st@aol.com <Recon1st@aol.com> |