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Master Thesis ”State Space Control of Primary Linear Actuator”

Huskvarna, Sweden
Closing date
30 January 2022
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When designing electro-mechanical actuators for a primary or secondary flight control system one must take into account a lot of parameters that affect each other in various ways. In an electric actuator designed for primary flight control the performance and bandwidth are important aspects, but also how the system behaves under different conditions such as cold or stalled conditions. The most basic setup of an electrical linear actuator is a 3-phase PMSM motor together with a ball-screw. The actuator is controlled via a cascaded current, speed and position loop.

Description of the master thesis

This master thesis is about designing and improving the existing control design of one of our electrical primary flight actuator products. One goal is to improve the control system so that the non-linearity’s are mitigated. We believe that one possible solution is to look into a full state space feedback controller, but we are open to explore other control design solutions as well. Another goal is to increase the bandwidth of our actuator which we believe is partially improved by the full state space feedback design, but also by analyzing the sample times and dead-times of our hardware.

The electro-mechanical actuator is located on a flying aircraft and it is a strong possibility that the outcome of this master thesis will be implemented in the existing design and future projects.

Possible approaches/suggestions:

  • Study the theory of electrical actuators and the relevant Simscape models
  • Design a full state feedback controller (or suggest other design) in Simscape/Simulink
  • Evaluate performance of new implementation vs the current implementation in Simscape/Simulink
  • Evaluate improvements for SW/HW, e.g. changed sample time, optimized current sampling, FPGA solutions
  • Implement solution from Simulink to C code and test on real hardware

Some previous master theses at Saab related to this area:

What you will be a part of

Business unit Surveillance offers solutions for surveillance, decision support, and detection and protection against different types of threats. Within Surveillance there is a product group called Actuation & Utility that focus on electro-mechanical actuators for Primary/secondary flight and utility systems.

Your profile

The master thesis is suitable for 1-2 students with an interest in Control theory design. It is recommended that you have had courses or background in control theory design incl. state space control and/or non-linear control design.

You are at the end of your technical master education in Engineering Physics, Electrical Engineering, or equivalent, and are eligible for your 30 HP degree project.


Mattias Johansson, Systems Engineer at Saab Huskvarna