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R. Sharma - One of the best experts on this subject based on the ideXlab platform.
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Design and Analysis of a Variable Buoyancy System for Efficient Hovering Control of Underwater Vehicles with State Feedback Controller
Journal of Marine Science and Engineering, 2020Co-Authors: B K Tiwari, R. SharmaAbstract:The design process for Variable Buoyancy System (VBS) is not known in full, and existing approaches are not scalable. Furthermore, almost all the small size Autonomous Underwater Vehicles/Gliders (AUVs/G’s) use very low capacity of Buoyancy change (in the range of few milliliters) and the large size AUVs require large Buoyancy change. Especially for adverse weather conditions, emergency recovery or defense-related applications, higher rate of rising/sinking (heave velocity) is needed along with an ability to hover at certain depth of operation. Depth of UVs can be controlled either by changing the displaced volume or by changing the overall weight and, herein, our focus is on the later. This article presents the problem of design and analysis of VBS for efficient hovering control of underwater vehicles at desired depth using the state feedback controller. We formulate and analyze the design and analysis approach of VBS using the fundamental of mechanics, System dynamics integration and control theory. Buoyancy is controlled by changing the overall weight of the vehicle using the ballasting/de-ballasting of water in ballast tanks through the use of Positive Displacement Pump (PDP) for control in heave velocity and hovering depth. Furthermore, detailed mass metric analysis of scalable design of VBS for different Buoyancy capacities is performed to analyze the overall performance of the VBS. Also, the performances of AUVs integrated with VBS of different Buoyancy capacities are investigated in both the open loop and closed loop with the LQR state feedback controller. Hovering performance results are presented for three Design Examples (DEs) of AUVs with 2.8 m, 4.0 m and 5.0 m length and they are integrated with various Buoyancy capacities at 9 kg/min rate of change of Buoyancy. Results indicate that the AUVs achieve the desired depth with almost negligible steady state error and when they reach the desired hovering depth of 400 m the maximum pitch angle achieved of 16.5 degree for all the Des is observed. Maximum heave velocity achieved during sinking is 0.44 m/s and it reduces to zero when the vehicle reaches the desired depth of hovering. The presented computer simulation results indicate good performance and demonstrate that the designed VBS is effective and efficient in changing the Buoyancy, controlling and maintaining the depth, controlling the heave velocity and can be used in rescue/attack operations of both the civil and defense UVs.
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A Computing Model for Design of Flexible Buoyancy System for Autonomous Underwater Vehicles and Gliders
Defence Science Journal, 2018Co-Authors: Brajesh Tiwari, R. SharmaAbstract:Modern design approaches are conceived and utilised in an integrated loop covering System statics, dynamics, optimisation, and others. In this regard this paper presents a computing based integrated design approach for a flexible Buoyancy System (FBS) aimed towards the applications in autonomous underwater vehicles and gliders. The primary design alternatives for the FBS are: piston and pump driven and both are investigated. The primary design of autonomous underwater vehicles and gliders is computed from first principle of mechanics and defined in the computer aided design model and it is implemented in the Matlab*TM. Lastly, to show the application of the present approach, a design example is presented for a water depth of 6000 m.
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A computing based design model of pneumatic driven variable buoayncy System for Autonomous Underwater Vehicles
OCEANS 2016 MTS IEEE Monterey, 2016Co-Authors: Patitapaban Sahoo, R. Sharma, T AsokanAbstract:In the era of modern computing based environment, the process of design is conceptualized, implemented and tested in a close loop integrating different modules of design, manufacturing and usages. In this regard, this paper presents a computing based design model for the design of a ‘Pneumatic Driven Variable Buoyancy System (PDVBS)’ for ‘Autonomous Underwater Vehicles (AUVs)’. The presented design model is modular in architecture and integrates the design of PDVBS with design of AUV. The design approach is derived from the basic and advanced principles of mechanics and the approach is defined in the ‘Computer Aided Design (CAD)’ model in terms of different modules with implementation in Matlab*™. Finally, we present a design example of a PDVBS for depth rating up to 4200 m with application focused on a large AUV of length 7 m to show the efficiency and applicability of our proposed design model.
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a computer simulation model for design of variable Buoyancy System for autonomous underwater vehicles gliders
OCEANS 2016 - Shanghai, 2016Co-Authors: B K Tiwari, R. Sharma, T AsokanAbstract:The efficient control of Buoyancy with low power is critically important in the design of new age ‘Autonomous Underwater Vehicles/Gliders (AUVs/Gs)’. This paper presents a ‘Computer Simulation Model (CSM)’ for the primary design of ‘Variable Buoyancy System (VBS)’ for AUVs/AUGs to efficient control Buoyancy and the simulation model is built in the environment of integration, modular architecture and specific range of applicability. The CSM for design of VBS is integrated in the overall design process of AUVs/AUGs. Finally, we present design example of the VBS for a AUVhaving two ballast tanks (each of a Buoyancy capacity of ± B = 10kg), maximum rate of change of Buoyancy = 9 kg/minute; and our presented results show that the proposed CSM for the design of VBS for AUVs/AUGs simulates the design process efficiently and leads to an efficient and economic design with the desired and specific range of applications.
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A computer simulation model for design of variable Buoyancy System for autonomous underwater vehicles/gliders
OCEANS 2016 - Shanghai, 2016Co-Authors: B K Tiwari, R. Sharma, T AsokanAbstract:The efficient control of Buoyancy with low power is critically important in the design of new age ‘Autonomous Underwater Vehicles/Gliders (AUVs/Gs)’. This paper presents a ‘Computer Simulation Model (CSM)’ for the primary design of ‘Variable Buoyancy System (VBS)’ for AUVs/AUGs to efficient control Buoyancy and the simulation model is built in the environment of integration, modular architecture and specific range of applicability. The CSM for design of VBS is integrated in the overall design process of AUVs/AUGs. Finally, we present design example of the VBS for a AUVhaving two ballast tanks (each of a Buoyancy capacity of ± B = 10kg), maximum rate of change of Buoyancy = 9 kg/minute; and our presented results show that the proposed CSM for the design of VBS for AUVs/AUGs simulates the design process efficiently and leads to an efficient and economic design with the desired and specific range of applications.
T Asokan - One of the best experts on this subject based on the ideXlab platform.
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A computing based design model of pneumatic driven variable buoayncy System for Autonomous Underwater Vehicles
OCEANS 2016 MTS IEEE Monterey, 2016Co-Authors: Patitapaban Sahoo, R. Sharma, T AsokanAbstract:In the era of modern computing based environment, the process of design is conceptualized, implemented and tested in a close loop integrating different modules of design, manufacturing and usages. In this regard, this paper presents a computing based design model for the design of a ‘Pneumatic Driven Variable Buoyancy System (PDVBS)’ for ‘Autonomous Underwater Vehicles (AUVs)’. The presented design model is modular in architecture and integrates the design of PDVBS with design of AUV. The design approach is derived from the basic and advanced principles of mechanics and the approach is defined in the ‘Computer Aided Design (CAD)’ model in terms of different modules with implementation in Matlab*™. Finally, we present a design example of a PDVBS for depth rating up to 4200 m with application focused on a large AUV of length 7 m to show the efficiency and applicability of our proposed design model.
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a computer simulation model for design of variable Buoyancy System for autonomous underwater vehicles gliders
OCEANS 2016 - Shanghai, 2016Co-Authors: B K Tiwari, R. Sharma, T AsokanAbstract:The efficient control of Buoyancy with low power is critically important in the design of new age ‘Autonomous Underwater Vehicles/Gliders (AUVs/Gs)’. This paper presents a ‘Computer Simulation Model (CSM)’ for the primary design of ‘Variable Buoyancy System (VBS)’ for AUVs/AUGs to efficient control Buoyancy and the simulation model is built in the environment of integration, modular architecture and specific range of applicability. The CSM for design of VBS is integrated in the overall design process of AUVs/AUGs. Finally, we present design example of the VBS for a AUVhaving two ballast tanks (each of a Buoyancy capacity of ± B = 10kg), maximum rate of change of Buoyancy = 9 kg/minute; and our presented results show that the proposed CSM for the design of VBS for AUVs/AUGs simulates the design process efficiently and leads to an efficient and economic design with the desired and specific range of applications.
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A computer simulation model for design of variable Buoyancy System for autonomous underwater vehicles/gliders
OCEANS 2016 - Shanghai, 2016Co-Authors: B K Tiwari, R. Sharma, T AsokanAbstract:The efficient control of Buoyancy with low power is critically important in the design of new age ‘Autonomous Underwater Vehicles/Gliders (AUVs/Gs)’. This paper presents a ‘Computer Simulation Model (CSM)’ for the primary design of ‘Variable Buoyancy System (VBS)’ for AUVs/AUGs to efficient control Buoyancy and the simulation model is built in the environment of integration, modular architecture and specific range of applicability. The CSM for design of VBS is integrated in the overall design process of AUVs/AUGs. Finally, we present design example of the VBS for a AUVhaving two ballast tanks (each of a Buoyancy capacity of ± B = 10kg), maximum rate of change of Buoyancy = 9 kg/minute; and our presented results show that the proposed CSM for the design of VBS for AUVs/AUGs simulates the design process efficiently and leads to an efficient and economic design with the desired and specific range of applications.
Rong Zheng - One of the best experts on this subject based on the ideXlab platform.
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the design and analysis of variable Buoyancy System of auv
2017 2nd Asia-Pacific Conference on Intelligent Robot Systems (ACIRS), 2017Co-Authors: Rong Zheng, Mozhu Li, Hongguang LiangAbstract:The sailing posture of AUV in water will be affected by the density, depth of seawater and so on. The sailing posture of AUV will be changed when crossing the waters of different hydrological environment. For maintaining a good sailing posture of AUV, we designed a variable Buoyancy System. The variable Buoyancy System can change the Buoyancy of AUV by changing the oil of the outer oil sac to ensure that AUV can get a good posture. We can get a series of test data by the AMESim simulation of the no-load operation and loading operation of the hydraulic System and the test on the lake. Finally, the test data are compared with simulation data, and it can provide reliable reference for System optimization. The results showed that the flow of variable Buoyancy System is affected by the depth of water and the temperature of environment, and variable Buoyancy System can steadily operate and satisfy the engineering needs.
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the resistance analysis of auv based on variable Buoyancy System
Robotics and Biomimetics, 2016Co-Authors: Rong ZhengAbstract:With the development of autonomous underwater vehicle (AUV), the long distance and large depth is the main development direction of AUV. Using the equipment of Buoyancy adjusting instead of the motors of the bow and stern channel can save energy and increase endurance of AUV. Based on the oil capsules device of Buoyancy adjusting in this paper, designed two different schemes: one is that oil capsules are installed outside of the AUV; the other is that oil capsules are installed inside of the AUV. We calculate the resistance of two schemes based on CFD. By comparing the resistance under the same scheme at different speeds (3km, 4km, 5km) and in different schemes at the same speed, we can get the most optimal scheme.
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ROBIO - The resistance analysis of AUV based on Variable Buoyancy System
2016 IEEE International Conference on Robotics and Biomimetics (ROBIO), 2016Co-Authors: Rong ZhengAbstract:With the development of autonomous underwater vehicle (AUV), the long distance and large depth is the main development direction of AUV. Using the equipment of Buoyancy adjusting instead of the motors of the bow and stern channel can save energy and increase endurance of AUV. Based on the oil capsules device of Buoyancy adjusting in this paper, designed two different schemes: one is that oil capsules are installed outside of the AUV; the other is that oil capsules are installed inside of the AUV. We calculate the resistance of two schemes based on CFD. By comparing the resistance under the same scheme at different speeds (3km, 4km, 5km) and in different schemes at the same speed, we can get the most optimal scheme.
Bahadir Beyazay - One of the best experts on this subject based on the ideXlab platform.
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design and development of low cost variable Buoyancy System for the soft grounding of autonomous underwater vehicles
2005Co-Authors: Jeffery S Riedel, Anthony J Healey, David B Marco, Bahadir BeyazayAbstract:Abstract : To provide a vehicle with the ability to hold position in a coastal environment requires a significant amount of onboard power. This power requirement either forces the vehicle size to increase to allow for suitable mission duration or reduces the amount of time the vehicle has to conduct its mission. To relax the power requirement, we propose to develop vehicles that can employ a bottom-sitting or soft grounding behavior. To obtain this behavior requires vehicles that have the capability to selfballast. By optimally positioning itself and sitting on the bottom, the AUV can be placed in a sleep mode, with only monitoring sensors awake, thereby conserving power. In this paper we present the preliminary work conducted in the areas of simulation, design and testing of a Variable Buoyancy System (VBS) for an Autonomous Underwater Vehicle (AUV). This Buoyancy System will be integrated into the new NPS AUV which is currently under construction, to support the upcoming joint operations with the University of Lisbon's MARIUS vehicle. We will discuss the tradeoffs and analysis that went into the design of the System, as well as the challenges associated with the integration of such a behavior and System into the vehicle.
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Design and Development of Low Cost Variable Buoyancy System for the Soft Grounding of Autonomous Underwater Vehicles" Proceedings of 11th International Symposium on Unmanned Untethered Submersible Technology (UUST'99), August 22-25, 1999
1999Co-Authors: Jeffery S Riedel, Anthony J Healey, David B Marco, Bahadir BeyazayAbstract:To provide a vehicle with the ability to hold position in a coastal environment requires a significant amount of onboard power. This power requirement either forces the vehicle size to increase to allow for suitable mission duration or reduces the amount of time the vehicle has to conduct its mission. To relax the power requirement, we propose to develop vehicles that can employ a bottom-sitting or soft grounding behavior. To obtain this behavior requires vehicles that have the capability to selfballast. By optimally positioning itself and sitting on the bottom, the AUV can be placed in a sleep mode, with only monitoring sensors awake, thereby conserving power. In this paper we present the preliminary work conducted in the areas of simulation, design and testing of a Variable Buoyancy System (VBS) for an Autonomous Underwater Vehicle (AUV). This Buoyancy System will be integrated into the new NPS AUV which is currently under construction, to support the upcoming joint operations with the University of Lisbon's MARIUS vehicle. We will discuss the tradeoffs and analysis that went into the design of the System, as well as the challenges associated with the integration of such a behavior and System into the vehicle. INTRODUCTION Energy storage is limited in AUV’s. To assist with energy management, data gathering missions have been proposed where the vehicle should sit on the bottom and gather acoustic/video/chemical data over extended periods of time. In this grounding scenario, thrusters may be used. However, there are two disadvantages for this method: high energy consumption and restricted use close to the ocean bottom. The motivation for this paper is to study a low cost, simple soft grounding capability for a submersible vehicle using controllable ballast. For simplicity, water ballast is considered. The design of the control System is based on the NPS Phoenix AUV. The ballast System is designed to control the weight addition into or out of the two ballast tanks. Ballast control of vehicles is not a new subject and we can find many examples beginning in the 1900’s, the non-rigid airships are very good examples of ballast control. One of the most important elements of a non-rigid airship is the ballonet-System. A ballonet as seen in Figure 1 is an airbag (one or two of them) inside the envelope, which is provided with air from a blower or directly from the engine unit. The air could be removed from the ballonet through the valves. If the airship has a front and aft ballonet then the height and pitch of the airship can be steered. For example, if the aft bag is filled with more air, then the airship will become heavier in the rear part of the envelope and the ship will incline increasing the altitude of the ship by using the engines. As Figure 1 depicted, the airship can also be statically trimmed [1]. Control was manual. For most underwater vehicles, the depth / pitch control is normally provided by hydroplanes. As an example, consider the NPS Phoenix AUV, the MIT Odyssey and the WHOI Remus. At low speed however, the control surfaces provide reduced control authority and the ballast control problem is very complex due to nonlinear, time-varying, uncertain hydrodynamics. Inherent lags arising from the integration of ballast water flow rate commands into weight change makes the control difficult to stabilize. There are some designs that used a bang-bang control System [2]. The ARPA’s Unmanned Undersea Vehicle (UUV) employed a fuzzy logic ballast controller which was claimed to be comparable with the performance that can be obtained from standard control techniques, but does not require traditional linear or nonlinear design methods. Figure 1. Sectional elevation of the Parseval-Airship "PL VI", 1910. Report Documentation Page Form Approved OMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 2005 2. REPORT TYPE 3. DATES COVERED 4. TITLE AND SUBTITLE Design and Development of Low Cost Variable Buoyancy System for the Soft Grounding of Autonomous Underwater Vehicles 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Postgraduate School,Center for AUV Research,Monterey,CA,93943-5000 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S) 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES The original document contains color images. 14. ABSTRACT To provide a vehicle with the ability to hold position in a coastal environment requires a significant amount of onboard power. This power requirement either forces the vehicle size to increase to allow for suitable mission duration or reduces the amount of time the vehicle has to conduct its mission. To relax the power requirement, we propose to develop vehicles that can employ a bottom-sitting or soft grounding behavior. To obtain this behavior requires vehicles that have the capability to selfballast. By optimally positioning itself and sitting on the bottom, the AUV can be placed in a sleep mode, with only monitoring sensors awake, thereby conserving power. In this paper we present the preliminary work conducted in the areas of simulation, design and testing of a Variable Buoyancy System (VBS) for an Autonomous Underwater Vehicle (AUV). This Buoyancy System will be integrated into the new NPS AUV which is currently under construction, to support the upcoming joint operations with the University of Lisbon’s MARIUS vehicle. We will discuss the tradeoffs and analysis that went into the design of the System, as well as the challenges associated with the integration of such a behavior and System into the vehicle. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 12 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 2 In another fuzzy logic control model, a 15 state Kalman filter was developed to provide estimates of the motion variables and the applied lift and torque acting on the UUV. The control law decided between three possible control actions; pump water in both tanks, pump water out of both tanks and turn both pumps off. The fuzzy input state space was composed of depth error and depth rate, and each is divided into partitions. The fuzzy controller interpolated between the partitions allowing the control to vary smoothly as the states move from one partition to another. These movements of states were provided by on and off of ballast pumps [3]. In this paper we outline the development of a depth controller using sliding mode control techniques for a neutrally buoyant vehicle. The sliding mode controller is designed on the basis of the simplified four degrees of freedom vertical plane equations of motion. A linear quadratic regulator (LQR) proportional approach is then utilized for the design of the ballast controller, which produces flow rate commands, allowing the vehicle to have a soft grounding behavior. These two controllers use a logic based depth regulator to provide realistic simulation of the vehicle’s flight and grounding operations in a single mission. VEHICLE MODELING AND EQUATIONS OF MOTION We will deal with only vertical plane variables; i.e., heave, pitch, and surge. The vertical plane stability analysis involves heave and pitch motions. However, the surge equation couples into pitch and heave through the offset, zG. This is a dynamic coupling, and could be eliminated by redefining hydrodynamic coefficients with respect to the ship’s center of gravity instead of its geometric center. Restricting the motions of the vehicle to the vertical (dive) plane, the only significant motions that must be incorporated to model the vehicle in the dive plane are, the surge velocity (u), the heave velocity (w), the pitch velocity (q), the pitch angle (θ ) and the global depth position (Z). q = θ& θ θ ρ δ α δ δ sin ) ( cos ) ( ) ( ) ( 2 1 ) ( ) ( ) ( ) ( 3 2 B z W z B x W x xdx xq w xq w x b C M M U Uw M wq mz Uq mx M q M I w M mx
Nuno Cruz - One of the best experts on this subject based on the ideXlab platform.
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Development of an Electrohydraulic Variable Buoyancy System
Information-an International Interdisciplinary Journal, 2019Co-Authors: João Carneiro, João Bravo Pinto, Nuno Cruz, Fernando Gomes De AlmeidaAbstract:The growing needs in exploring ocean resources have been pushing the length and complexity of autonomous underwater vehicle (AUV) missions, leading to more stringent energy requirements. A promising approach to reduce the energy consumption of AUVs is to use variable Buoyancy Systems (VBSs) as a replacement or complement to thruster action, since VBSs only require energy consumption during limited periods of time to control the vehicle’s floatation. This paper presents the development of an electrohydraulic VBS to be included in an existing AUV for shallow depths of up to 100 m. The device’s preliminary mechanical design is presented, and a mathematical model of the device’s power consumption is developed, based on data provided by the manufacturer. Taking a standard mission profile as an example, a comparison between the energy consumed using thrusters and the designed VBS is presented and compared.
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Development of an electromechanical variable Buoyancy System for shallow water operations
OCEANS 2019 - Marseille, 2019Co-Authors: João Carneiro, João Bravo Pinto, Fernando Gomes De Almeida, Nuno CruzAbstract:Autonomous underwater vehicles (AUVs) are becoming increasingly ubiquitous due to the growing needs in exploring Ocean resources. One of the most challenging tasks in this domain relates to the energy these vehicles require, given the increase in the number of scientific payloads and on the mission complexity. One way to potentially reduce the amount of energy consumed during vertical motion is to replace or complement the thruster action with a controlled change of the vehicles floatation, using a variable Buoyancy System (VBS). This paper presents the development of an electromechanical VBS for shallow depths, up to 100 m, to be included in an existing AUV. A preliminary mechanical design is presented, along with a mathematical model allowing the calculation of the energy spent by this device, based on the components manufacturers’ data. A comparison between the energy consumption using thrusters and the designed VBS is presented.
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exp.at - Using a variable Buoyancy System for energy savings in an AUV
2019 5th Experiment International Conference (exp.at'19), 2019Co-Authors: João Carneiro, João Bravo Pinto, Fernando Gomes De Almeida, Nuno CruzAbstract:The energy requirements of thruster driven autonomous underwater vehicle (AUV) missions have been growing in recent years. Their complexity and length are continuously increasing due to the growth of undersea exploration. The use of variable Buoyancy Systems (VBS) can potentially lead to energy savings since consumption is only required for Buoyancy changes. As such, energy is only spent during limited periods of time, as opposed to thruster driven Systems, where consumption is typically continuous. In this work, an energetic comparison between thruster and VBS driven devices is performed for a specific mission profile and a defined set of parameters. The influence of the mission parameters is studied in order to determine which System leads to the lowest energy consumption. For the case study presented, it is shown that the use of VBS over thrusters can lead to considerable energetic savings.
