The marine domain is of great interest for Saab, but it is also a challenging environment to operate in. We are looking for a student to contribute to the framework of designing and evaluating motion control systems of thruster actuated underwater vehicles.
Your role
Background
The possible applications of underwater vehicles are vast, in both civil and military industry, as well for research purposes. Consequently, there are many types of underwater vehicles; manned or unmanned, remotely operated or fully autonomous. Depending on the application, the vehicle can be equipped with different types of actuators for achieving motion control (and even physical interaction with other objects). One common type of motion actuation is by utilizing a set of thrusters, with different orientations, enabling motion in multiple degrees of freedom.
A central aspect for obtaining a versatile and well-performing vehicle is of course the thruster configuration; how many there are, where they are positioned, how they are oriented and how much thrust they generate. But it is equally important to have an efficient and robust motion control system which enables the potential for complex maneuvers. This thesis aims to contribute to the framework of designing and evaluating such motion control systems at Saab.
Description of the Master's Thesis
The main objective of this work is to develop a framework for systematically evaluating the motion control system of thruster actuated underwater vehicles. The framework should be applicable to a wide range of vehicles and shall evaluate the system in terms of e.g. stability and controllability, for an envelope of states such as vehicle speed/attitude and water current.
The developed evaluation framework shall be applied to at least one vehicle configuration. The student may choose from a set of suitable Saab vehicles as reference.
However, the evaluation will be performed based on simulations. Hence, as an initial part of the work, a dynamic motion simulation model will be developed. Mechanical properties and hydrodynamic data will be provided.
Further, as part of the simulation model, a motion control system will be developed and implemented. Design of the control system shall be made using a model-based approach, and it shall enable motion in all six degrees of freedom.
As an optional part, depending on the student’s interest, it is also proposed to investigate how slight modifications of thruster configuration (position/orientation/thrust) impacts the controllability and stability (an excellent use case for the developed evaluation framework!). Alternatively, the student might also investigate optimization of thruster configuration to obtain specific performance/characteristics of the vehicle.
The thesis is proposed to consist of the following tasks:

• Conduct a literature review of design and evaluation of motion control for thruster actuated underwater vehicles
• Establish dynamic motion model of the chosen underwater vehicle(s)
• Develop and implement at least one motion controller, using model-based design.
• Develop framework for systematically evaluating the characteristics of the vehicle motion control
• Apply the develop evaluation framework to the chosen underwater vehicle(s)

Note that the content and scope of the thesis may be adapted based on the interests of the student
Your profile
The suggested work is suitable for a student with an interest in motion control, simulation and analysis. You are at the end of your education in engineering physics, or any other related field, and about to start your Master Thesis work for 30 hp.
This position requires that you pass a security vetting based on the current regulations around/of security protection. For positions requiring security clearance additional obligations on citizenship may apply.
What you will be a part of
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