Advanced ship autopilot system
First Claim
1. A method of navigation control for a vessel comprising the steps of:
- (a) providing a correlation processor for determining according lo a non-linear correlation a set of predictions of vessel motion based on a set of sensory input values;
(b) determining from the predictions and from actual vessel motion a control law of vessel motion;
(c) using the control law, forming a predictive controller for providing a control signal indicative of navigation control; and
, (d) at intervals updating the predictive controller based on another control law formed according to step (b).
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Abstract
A navigation controller and method for performing navigation control are provided. According to the method, a time varying prediction model is determined based on a predictor having a model component and a correlation processor component. The time varying linear prediction model is then used to formulate a predictive controller or to update the controller in use. The controller is then used to control navigation. Because of the correlation processor, the predictor is better adapted to compensate for shortcomings in the model thus making the automated navigation control superior. In use, the method controls vessel navigation in any of a number of predefined modes such as cruising and turning modes. Moreover, through the selection of the operational scenario, the controller can be made to adapt to differing control objectives—for example tight tracking or increased operational efficiency of the vessel.
64 Citations
31 Claims
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1. A method of navigation control for a vessel comprising the steps of:
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(a) providing a correlation processor for determining according lo a non-linear correlation a set of predictions of vessel motion based on a set of sensory input values;
(b) determining from the predictions and from actual vessel motion a control law of vessel motion;
(c) using the control law, forming a predictive controller for providing a control signal indicative of navigation control; and
,(d) at intervals updating the predictive controller based on another control law formed according to step (b). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
(a1) providing a linear mathematical model for predicting vessel motion in conjunction with the correlation processor.
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6. A method of navigation control for a vessel according to claim 5, wherein the mathematical model is a linear time varying mathematical model.
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7. A method of navigation control for a vessel according to claim 6, wherein the control law is of the form of Δ
- {overscore (u)}(t)=K{overscore (e)}(t) and wherein K is of the form of
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8. A method of navigation control for a vessel according to claim 7, wherein α
- is between 0.8 and 1.2.
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9. A method of navigation control for a vessel according to claim 8, wherein N is between 80 and 120.
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10. A method of navigation control for a vessel according to claim 9, wherein Kp is less than approximately 0.02.
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11. A method of navigation control for a vessel according to claim 5, wherein the mathematical model is a linear time invariant mathematical model determined recursively.
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12. A method of navigation control for a vessel according to claim 1, comprising the step of selecting a mode of operation from a plurality of supported modes of operation in which for the controller to operate.
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13. A method of navigation control for a vessel according to claim 12, wherein the supported modes include turning mode and cruising mode.
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14. A method of navigation control for a vessel according to claim 13, wherein the step of selecting a mode of operation is performed in advance by predicting vessel navigation within a turning horizon.
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15. A method of navigation control for a vessel according to claim 14, comprising the step of when in turning mode, maintaining the turning mode until a predetermined time has elapsed since the turn was completed.
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16. A method of navigation control for a vessel according to claim 14, wherein the supported modes include recovery mode and abort mode.
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17. A method according to claim 2, wherein the controller is capable of track-keeping, course-keeping, position keeping, stabilization, berthing, and speed control.
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18. A navigation control system comprising:
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a correlation processor for determining according to a non-linear correlation a set of predictions based on a set of sensory input values; and
,a modified generalized predictive controller designed based on the correlation processor predictions for providing a control signal indicative of navigation control. - View Dependent Claims (19, 20)
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21. An automated ship navigation control system for controlling a ship'"'"'s navigation comprising:
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a correlation processor for receiving input values and for determining according to a non-linear correlation of those values a set of predictions relating to ship navigation;
a sensor for determining the ship location and for providing a location signal indicative of the determined ship location to the correlation processor;
a sensor for sensing a slip state, the ship state including a physical setting of a ship system, and for providing a ship state signal indicative of the sensed ship state to the correlation processor;
means for providing values relating to a current control signal to the correlation processor;
a modified generalized predictive controller based on a time varying linear model determined from the set of predictions front the correlation processor and for providing a control signal indicative of navigation control, the modified generalized predictive controller for controlling differently in dependence upon at least one of a mode of operation and variations in the accuracy of the controller to cause the vessel to navigate along a predetermined path. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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28. A method of control for a process comprising the steps of:
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(a) providing a correlation processor for determining according to a non-linear correlation a set of predictions of process progress based on a set of sensory input values;
(b) determining from the predictions and from actual process progress a control law of the process;
(c) using the control law, forming a predictive controller for providing a control signal indicative of process control; and
,(d) at intervals updating the predictive controller based on another control law formed according to step (b). - View Dependent Claims (29, 30, 31)
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Specification