A non-follow-up system actuates the  solenoid valves by controlling  the steering actuator. Upon a steering request the valve(s) open completely, resulting in full force being applied to the rudder as long as input is given. Upon removal of the steering request the valve(s) closes again (time dependent control).

Full Follow-Up

A full follow-up system applies position feedback. The required rudder position is set on the steering control(s), upon which the solenoid valves are opened to control the steering actuator.
The actual position and requested position are continuously compared, resulting in automatic closure of the valves upon reaching the desired position (position dependent control).

Types of Solenoid Valves

Bang-Bang (black/white) Solenoid Valves

Bang-Bang solenoid valves are only capable of opening and closing completely. Once opened, full available force is applied to the rudder. Once closed, the rudder-applied force is terminated promptly.
This results in a fast response type of characteristic.

Proportional Solenoid Valves

Proportional solenoid valves are capable of opening and closing gradually. This results in a smooth increase of force being applied to the rudder. Upon closure of the valves, power is gradually reduced to zero resulting in a deceleration of the actuator. This results in smooth and accurate steering characteristics.

For more information about Northrop Grumman Sperry Marine’s Total Steering Systems, please  contact us.