Route optimizing and following for autonomous underwater vehicle ladder surveys

An autonomous underwater vehicle is able to conduct coverage detections, such as sea terrain mapping and submerged objects detection, using sonar. This work addresses the task of both optimizing and following routes that present a ladder shape. First, a planning method to determine a nearly optimal coverage route is designed. The track spacing is optimized considering the seabed type and the sonar range for the purpose of increasing detection probability. It also adds adaptability to confined water, such as harbors, by decomposing the geometrically concave mission region during the processing of the environmental data. Next, a decoupled and two-layered structure is adopted to design the following controller. The route is followed in the form of sequenced-lines tracking. A proportion–integral–derivative algorithm with fuzzy parameters adjustment is employed to calculate a reference heading angle according to the transverse position deviation in designing the guidance controller. An adaptive nonlinear S-surface law is adopted to design the yaw control. The route following the method is demonstrated with sonar (including side scanning sonar and multi-beam echo sounder) imagery collected in terrain mapping and object detection through sea trials.

Download Full-text

Iterative Self-Tuning Minimum Variance Control of a Nonlinear Autonomous Underwater Vehicle Maneuvering Model

Electronics ◽

10.3390/electronics10212686 ◽

2021 ◽

Vol 10 (21) ◽

pp. 2686

Author(s):

Maria Tomas-Rodríguez ◽

Elías Revestido Herrero ◽

Francisco J. Velasco

Keyword(s):

Autonomous Underwater Vehicle ◽

Control Method ◽

Linear Time ◽

Control Design ◽

Underwater Vehicle ◽

Minimum Variance ◽

Use Of Self ◽

Self Tuning ◽

Heading Angle ◽

Iteration Technique

This paper addresses the problem of control design for a nonlinear maneuvering model of an autonomous underwater vehicle. The control algorithm is based on an iteration technique that approximates the original nonlinear model by a sequence of linear time-varying equations equivalent to the original nonlinear problem and a self-tuning control method so that the controller is designed at each time point on the interval for trajectory tracking and heading angle control. This work makes use of self-tuning minimum variance principles. The benefit of this approach is that the nonlinearities and couplings of the system are preserved, unlike in the cases of control design based on linearized systems, reducing in this manner the uncertainty in the model and increasing the robustness of the controller. The simulations here presented use a torpedo-shaped underwater vehicle model and show the good performance of the controller and accurate tracking for certain maneuvering cases.

Download Full-text

Tracking the Movements of Juvenile Chinook Salmon using an Autonomous Underwater Vehicle under Payload Control

Applied Sciences ◽

10.3390/app9122516 ◽

2019 ◽

Vol 9 (12) ◽

pp. 2516 ◽

Cited By ~ 2

Author(s):

John H. Eiler ◽

Thomas M. Grothues ◽

Joseph A. Dobarro ◽

Rahul Shome

Keyword(s):

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Autonomous Underwater Vehicle ◽

Underwater Vehicle ◽

Environmental Data ◽

Movement Rate ◽

Movement Rates ◽

Juvenile Chinook Salmon ◽

Juvenile Chinook ◽

Location Estimate

An autonomous underwater vehicle (AUV) under payload control (PC) was used to map the movements of juvenile Chinook salmon (Oncorhynchus tshawytscha) tagged with acoustic transmitters. After detecting a tag, the AUV deviated from its pre-programmed route and performed a maneuver designed to enhance the location estimate of the fish and to move closer to collect proximal environmental data. Nineteen fish were released into marine waters of southeastern Alaska. Seven missions with concurrent AUV and vessel-based surveys were conducted with two to nine fish present in the area per mission. The AUV was able to repeatedly detect and estimate the location of the fish, even when multiple individuals were present. Although less effective at detecting the fish, location estimates from the vessel-based surveys helped verify the veracity of the AUV data. All of the fish left the area within 48 h of release. Most fish exhibited localized movements (milling behavior) before leaving the area. Dispersal rates calculated for the fish suggest that error associated with the location estimates was minimal. The average movement rate was 0.62 body length per second and was comparable to marine movement rates reported for other Chinook salmon stocks. These results suggest that AUV-based payload control can provide an effective method for mapping the movements of marine fish.

Download Full-text

Research on Motion Control of AUV with Hybrid Actuators

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.341-342.906 ◽

2013 ◽

Vol 341-342 ◽

pp. 906-912 ◽

Cited By ~ 1

Author(s):

Lei Zhang ◽

Da Peng Jiang ◽

Shu Ling Huang ◽

Jin Xin Zhao

Keyword(s):

Motion Control ◽

High Speed ◽

Autonomous Underwater Vehicle ◽

Underwater Vehicle ◽

Underwater Vehicles ◽

Velocity Control ◽

Yaw Control ◽

Depth Control ◽

System Vibration ◽

The Stability

A switch function is presented to smooth control instructions and avoid system vibration during switch operating underwater vehicles with hybrid actuators. And a Modified S-plane Controller (MSC) is proposed by analyzing underwater vehicles dynamics and taking static force and coupling effects between the longitude velocity and other dimensions into account. Besides the advantages of S controller such as simple structure, MSC can solve the motion control of underwater vehicle at high speed which is difficult to control with S-plane controller. The stability of MSC is analyzed with Lyapunov function. Finally, MSC is applied to the motion control of an autonomous underwater vehicle controlled by rudders and thrusters. The feasibility of MSC is demonstrated by the results of velocity control, yaw control and depth control tests.

Download Full-text