Device for controlling a cycloid propeller for watercraft
AssigneesSiemens Aktiengesellschaft, J. M. Voith GmbH
InventorsJosef Hochleitner, Harald Gross
Life of this patent
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Abstract
To enable an exact and quick adjustment of the control point of a cycloid propeller ("Voith-Schneider-Propeller"), hydraulic adjustment cylinders are provided with electric proportional valves whose set value is determined by a cylinder stroke control circuit--preferably by way of an auxiliary valve current control circuit and a valve position control circuit. The travel and the rudder commands are transformed, by means of incremental transmitters which limit the adjustment velocity as a function of the load and the travel direction, according to suitable characteristics to control inputs which are transformed from ship coordinates to actuator coordinates and converted according to Pythagoras' theorem to set values for the cylinder strokes.
Claims14
In a watercraft including a drive mechanism and a cycloid propeller coupled thereto, a control for controlling said propeller comprising:
- (a) a hydraulic circuit including two hydraulic adjustment cylinders having pistons therein, each said cylinder being mounted so as to be rotatable about a separate, substantially vertical axis, at least two electrohydraulic proportional valves for respectively connecting said cylinders in a hydraulic circuit, the pistons of said cylinders being secured to a shiftable joint control point for determining the position of the control point;
- (b) means for adjusting the pitches of the pivoting blades of the propeller as a function of the eccentricities of the control point such that the pivoting blades exhibit a travel pitch producing a thrust force component in the direction of the longitudinal axis of the watercraft, and exhibit a rudder pitch producing a thrust force component in the direction of the rudder axis of the watercraft generally perpendicular to the longitudinal axis thereof;
- (c) a first arithmetic unit for generating from a travel command and a rudder command respective pitch set values for the travel pitch and rudder pitch as a function of ship coordinates;
- (d) transformer means for generating eccentricities from said pitch set values as a function of the adjustment of the adjustment cylinders;
- (e) a second arithmetic unit for calculating from said generated eccentricities stroke set values for the adjustment cylinders;
- (f) at least one measuring unit for determining the actual values of the stroke of each cylinder;
- and
- (g) at least one cylinder stroke control circuits respectively coordinated with said cylinders for each generating, from the respective stroke set value and the cylinder stroke actual value, a valve current set value, said stroke control circuits each including control means for continuously changing the flow through said electrohydraulic proportional valves in accordance with said valve current set value.
Dependencies are inferred from the claim text.