Effective Turning Motion Control of Internally Actuated Autonomous Underwater Vehicles

Abstract

This paper presents a novel roll mechanism and an efficient control strategy for internally actuated autonomous underwater vehicles (AUVs). The developed control algorithms are tested on Michigan Tech's custom research glider, ROUGHIE (Research Oriented Underwater Glider for Hands-on Investigative Engineering), in a controlled environment. The ROUGHIE's design parameters and operational constraints were driven by its requirement to be man portable, expandable, and maneuverable in shallow water. As an underwater glider, the ROUGHIE is underactuated with direct control of only depth, pitch, and roll. A switching control method is implemented on the ROUGHIE to improve its maneuverability, enabling smooth transitions between different motion patterns. This approach uses multiple feedforwardfeedback controllers. Different aspects of the roll mechanism and the effectiveness of the controller on turning motion are discussed based on experimental results. The results illustrate that the ROUGHIE is capable of achieving tight turns with a radius of 2.4 meters in less than 3 meters of water, or one order of magnitude improvement on existing internally actuated platforms. The developed roll mechanism is not specific to underwater gliders and is applicable to all AUVs, especially at lower speeds and in shallower water when external rudder is less effective in maneuvering the vehicle.

Compact Quantum Magnetometer System on an Agile Underwater Glider

“…To experimentally validate the effectiveness of utilizing a compact quantum magnetometer on an agile underwater glider, the authors modified a custom underwater glider, ROUGHIE. A detailed discussion of the platform [ 13 ], controller design [ 20 ], and operation [ 18 , 19 ] are available in prior publications.…”

“…Over the past several years the Research-Oriented Underwater Glider for Hands-on Investigative Engineering (ROUGHIE), Figure 1 , has been developed as a modular, low-cost, and highly-maneuverable underwater glider [ 13 , 18 , 19 , 20 ]. ROUGHIE is affordable at 10% of the cost of commercial underwater gliders.…”

Extending Maneuverability of Internally Actuated Underwater Gliders, An Attempt to Develop an Open Platform For Research and Education

“…GUPPIE [94], a Glider for Underwater Problem-solving and Promotion of Interest in Engineering, was developed with three main traits: 1) it has great potential in engaging students with a wide range of interests [83]; 2) it is a theme-based robotics program that has real-life applications [61]; and 3) it presents autonomy in an underwater environment that introduces new but intriguing challenges. In 2016, the GUPPIE was redesigned to be more user friendly for middle school students.…”

Extending Maneuverability of Internally Actuated Underwater Gliders, an Attempt to Develop an Open Platform for Research and Education

“…This strategy can be used to generate spiraling motion and turning maneuvers in internally actuated underwater gliders.Similar to the 2D gliding, the hydro-static lift is the control action on the vehicle.The lift force on the rolled wing has a horizontal component that acts as centripetal force and causes the glider to change its heading and turn. By maintaining this horizontal force the glider stays in a helical motion upward or downward depending on its orientation in the vertical plane.Heading control is achieved in two different ways in the ROUGHIE, either a direct feedforward approach or a hybrid feedforward-feedback approach[53], Case 1: The γ angle is sent directly to the servo as control input and is used for either system identification or feedforward-based inverse mapping implementation. Case 2: The γ angle is obtained through feedforward-feedback control of φ and it is used for longterm turn control, or if the system has not been properly characterized following changes to the vehicle structure.…”

“…However, there are not many educational programs to promote marine robotics nationwide. One reason is that underwater vehicle development is challenging due to the physical design constraints and unforgiving environment, typical of many real-world engineering problems[28,61]. The more challenging reason is the barrier to entry for beginners with no prior knowledge.…”