In this project, we’ve upgraded an ASD’s maneuvering ability by means of two functionality over the vessel: Omega-Control improvement & upgrading 2×180 to the 2×360 degree rotation over the azimuth thrusters.

==>What is the “omega control” function of the Japanese made gearbox’s clutch of an azimuth thruster propulsion of a marine-ASD push-tug & why it’s an essential means for vessel’s maneuvering???

 

Normally, the marine-ASD push-tugs are categorized in two main models (from marine remote control point of view):

1- Digital Control role embedded, comprising the clutch on/off functioning over the azimuth thrusters.

2- Analogue controlling model, comprising the CPP or VFD (Variable Frequency Drive) based azimuth thrusters.

The CPP model is comprising a controllable pitch propeller, as long as RPM control over the engine & sophisticated analogue control over a predefined range (providing smooth maneuvering ability).
But, regarding the digital control model (clutch on/off), some makers to provide more economical solutions, they would rather prefer to simplify the equipment by means of a fixed-pitch propeller & consequently less maneuvering ability (the only applicable option is to control the shaft RPM).

==>As an Intermediate solution & an option to the digital on/off clutch models, there is a Japanese invention:

Omega-Control-scheme: the manipulated role to the clutch control software & hardware by means of an analogue signal to enable the smooth-clutch ability over the gearbox & preventing immediate engagement and consequently abrupt force to the propeller.
Nowadays we’ve been witnessing the sophisticated control schemes over analogue output signal of the PLC to an intermediate proportional-valve located over the gearbox to reduce the clutch force & causes the output shaft speed reduces dramatically.

This intermediate role shall provide improved maneuverability to the operator to control the forces of the propeller.

For old models, an analogue control air signal which might be provided through an E/P-converter.

==> Also, what is determinative in between is the ability of an ASD push-tug to bring about a kind of the braking-force by means of the opposition-forces & confrontation of the thrust-direction (s), smoothly initiating from ahead direction and turning against each-others inward the vessel.
To apply the braking force, operator has to gradually rotate the levers & makes the azimuth-thruster‘s thrust direction inward the vessel & try to keep them in front of each others & as an resultant forces shall lead to reduce the acceleration over the vessel.

==> But, if the thrusters had not been equipped with Omega-Control scheme, vessel would probably has faced with excessive vibration, which might be harmful to the gearboxes & might be required to add some thrust force dampers inside the gearbox.
==> How to implement Omega-Control scheme: by means of a proportional hydraulic control over the clutch operating oil.
The omega system shall control the operating oil pressure & control it to bring about a smooth face to face clutch engagement & enable the slipping function.

==> User friendly option: herewith we’ve established an automatic-clutch engagement mode by means of the predefined control lever’s thrust percent which is being monitored by the PLC controller & establishing the relevant omega control subroutine to do so.
As per the attached video, when the thrust lever passes through almost 35% of the full range, the omega control is being activated & clutch smoothly trying to rotate the shaft in a slipping mode & relevant smooth thrust over the propeller shall be presented.

==> Simultaneously, we’ve upgraded the functionality of the azimuth thrusters rotation angles from 180 to 360 degree full round azimuth angle:

 

 

Herewith, we’ve attached the before & after bridge control consul snap shots: