Granted Patent B2

US 10,747,226 · App. 15/620,675 · Granted Aug 18, 2020

Inventors: Mark Johnson (Vannes, FR); Ian Matt (Fareham, GB); Christopher Yeomans (Fareham, GB); Gytis Sabaliauskas (Fareham, GB); Gordon Pope (Kowloon, HK)

Assignee: FLIR Systems, Inc.

G05D1/0206B63H25/04B63H25/06G01S15/86G01S15/89B63B2035/009B63H2025/045G01S15/96G01S19/42

Abstract

Claims (80)

1. A system comprising:

a logic device configured to receive one or more sensor signals and generate one or more control signals to provide directional control for a mobile structure along a reference path, wherein the logic device is configured to perform a method comprising:

receiving a yaw rate, position, and velocity of the mobile structure;

determining a cross track error relative to the reference path for the mobile structure based, at least in part, on the yaw rate, position, and velocity;

determining a steering demand for the mobile structure based, at least in part, on the cross track error;

receiving a steering angle and a steering rate of the mobile structure, wherein the steering angle is based, at least in part, on the steering demand;

determining a nominal steering angle based, at least in part, on the steering rate;

determining a nominal feedback signal based, at least in part, on a difference between the nominal steering angle and the steering angle; and

adjusting the steering demand by the nominal feedback signal.

2. The system of claim 1 , wherein the determining the cross track error comprises at least one of:

determining a cross track acceleration for the mobile structure based, at least in part, on the yaw rate;

integrating a cross track acceleration for the mobile structure to determine a cross track velocity for the mobile structure, the cross track acceleration based, at least in part, on the yaw rate; or

integrating a cross track velocity for the mobile structure to determine the cross track error for the mobile structure.

3. The system of claim 2 , wherein the determining the steering demand comprises multiplying the cross track acceleration, cross track velocity, and/or cross track error by one or more associated gains.

4. The system of claim 2 , wherein the integrating the cross track acceleration uses a position-based cross track velocity derived, at least in part, from measured positions of the mobile structure.

5. The system of claim 1 , wherein the method further comprises:

determining a bearing associated with the reference path; and

determining a cross track velocity reference using the bearing, wherein the cross track error is based, at least in part, on the cross track velocity reference.

6. The system of claim 1 , further comprising the mobile structure, wherein:

the mobile structure is a watercraft comprising a steering actuator and a rudder;

the steering angle comprises a rudder angle;

the steering rate comprises a yaw rate;

the nominal steering angle comprises a nominal rudder angle; and

the steering actuator is configured to receive the steering demand and actuate the rudder to maintain the watercraft along the reference path.

7. The system of claim 1 , wherein the method further comprises limiting the steering demand according to a maximum acquisition angle associated with the mobile structure, wherein the limiting is performed in response to a user selected responsiveness setting.

8. The system of claim 1 , further comprising a user interface configured to display the steering demand and/or an angle associated with the steering demand to a user.

9. The system of claim 1 , wherein the reference path is a specified track between at least two waypoints.

10. The system of claim 1 , wherein the reference path is a specified contour associated with a sea bed depth, wherein the cross track error is an effective cross track error based on a depth error divided by a cross slope associated with the specified contour.

11. The system of claim 10 , wherein:

the system further comprises a sonar system;

the method further comprises:

controlling the sonar system to determine the depth and the cross slope;

determining the depth error by subtracting a target depth of the specified contour from the depth; and

determining the effective cross track error by dividing the depth error by the cross slope.

12. The system of claim 1 , wherein the method further comprises determining a nominal steering rate, wherein the determining the nominal steering rate comprises:

processing the steering rate with a nominal predictor;

receiving the nominal steering angle from the nominal predictor, wherein the nominal predictor comprises a transfer function configured to model dynamics of a nominal mobile structure derived, at least in part, from a selection of mobile structures; and

wherein the transfer function comprises a ratio of a nominal steering rate lag term to a nominal steering rate gain term.

13. The system of claim 12 , wherein:

the nominal steering rate lag is set to zero within the nominal predictor; and

the determining the nominal feedback signal comprises determining a delayed steering angle based, at least in part, on the steering angle, and determining a difference between the nominal steering angle and the delayed steering angle.

14. The system of claim 1 , wherein the method further comprises:

limiting the steering demand to produce a steering actuator rate demand less than a steering actuator rate limit and/or a steering demand less than a steering actuator angle limit;

receiving a user-selectable responsiveness setting; and

modifying, based on the responsiveness setting, one or more gains, a deadband, and/or a limit used to determine the steering demand.

15. The system of claim 1 , wherein the method further comprises:

providing the adjusted steering demand to a steering actuator.

16. The system of claim 1 , wherein the method further comprises:

providing the nominal feedback signal to a single-band or multi-band bandwidth-selectable filter to produce a filtered nominal feedback signal;

adjusting the steering demand using the filtered nominal feedback signal; and

modifying at least one bandwidth of the bandwidth-selectable filter based on a user-selectable responsiveness setting.

17. The system of claim 1 , wherein:

the yaw rate is determined after a pitch, pitch rate, roll, and/or roll rate of the mobile structure are determined to reduce a pitch-induced noise in the yaw rate.

18. The system of claim 1 , wherein the mobile structure is a watercraft comprising:

a rudder;

a steering actuator configured to receive the steering demand provided as one of the control signals and configured to actuate the rudder;

a steering sensor fixed relative to the watercraft and configured to provide the steering angle as at least a first one of the sensor signals; and

a steering rate sensor fixed relative to the watercraft and configured to provide the steering rate as at least a second one of the sensor signals.

19. A system comprising:

a logic device configured to receive one or more sensor signals and generate one or more control signals to provide directional control for a mobile structure along a reference path, wherein the logic device is configured to perform a method comprising:

receiving a yaw rate, position, and velocity of the mobile structure;

determining a cross track error relative to the reference path for the mobile structure based, at least in part, on the yaw rate, position, and velocity;

determining a steering demand for the mobile structure based, at least in part, on the cross track error;

receiving a steering angle and a steering rate of the mobile structure, wherein the steering angle is based, at least in part, on the steering demand;

determining a nominal steering angle based, at least in part, on the steering rate; and

determining a nominal steering rate, wherein the determining the nominal steering rate comprises:

processing the steering rate with a nominal predictor;

receiving the nominal steering angle from the nominal predictor, wherein the nominal predictor comprises a transfer function configured to model dynamics of a nominal mobile structure derived, at least in part, from a selection of mobile structures; and

wherein the transfer function comprises a ratio of a nominal steering rate lag term to a nominal steering rate gain term.

20. A system comprising:

a logic device configured to receive one or more sensor signals and generate one or more control signals to provide directional control for a mobile structure along a reference path, wherein the logic device is configured to perform a method comprising:

receiving a yaw rate, position, and velocity of the mobile structure;

determining a cross track error relative to the reference path for the mobile structure based, at least in part, on the yaw rate, position, and velocity;

determining a steering demand for the mobile structure based, at least in part, on the cross track error;

receiving a steering angle and a steering rate of the mobile structure, wherein the steering angle is based, at least in part, on the steering demand;

determining a nominal steering angle based, at least in part, on the steering rate;

determining a nominal feedback signal based, at least in part, on a combination of the steering angle and the nominal steering angle;

providing the nominal feedback signal to a single-band or multi-band bandwidth-selectable filter to produce a filtered nominal feedback signal;

adjusting the steering demand using the filtered nominal feedback signal; and

modifying at least one bandwidth of the bandwidth-selectable filter based on a user-selectable responsiveness setting.

Assignments (2)

Continuity (18)

Cited By (2)

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