Control of Fluid Power and Electrical Servomechanisms


Content, progress and pedagogy of the module

Learning objectives


  • Have gained an understanding of analysis, design and control of hydraulic servo mechanisms
  • Have gained knowledge about methods for electro-mechanical energy conversion by means DC and square-wave brushless machines
  • Have gained knowledge about the construction, the operating principles, the modelling and the performance characteristics for DC and brushless machines
  • Have a basic understanding about closed-loop control principles for DC and brushless machines for servo applications
  • Have a fundamental understanding of permanent magnet materials and their applications in electric actuators
  • Have gained knowledge about methods for electric energy conversion by power electronic converters
  • Have gained knowledge about active and passive power electronic components and their use in power converters.
  • Have gained an understanding of Lagrange equation and how it is used for modelling of a mechanical system.
  • Have a basic understanding of non-linarites in mechanical system including modal interaction.


  • Be able to set up the governing equations (physically based) for a hydraulic servo system
  • Be able to apply linear control strategies to a hydraulic servo system
  • Be able to analyse different kinds of DC machines and to formulate dynamic models hereof
  • Be able to calculate performance characteristics for the DC machine and to select a DC motor for a given application
  • Be able to analyse and to design servo systems using DC machines with speed, position and current feedback
  • Understand the basics of square-wave permanent magnet brushless machines and their applications for servo mechanisms
  • Be able to understand the operating principles for basic electric converters, including pulse-width modulated buck, boost, half- and full-bridge converters
  • Understand the fundamentals of semiconductor physics and the basic operating principles for power semiconductor devices such as power diodes and MOSFET’s
  • Be able to read power semiconductors datasheets, including understanding of switching characteristics and safe operating areas
  • Be able to design simple power electronic converters, including gate drivers and thermal aspects such as switching and conduction losses
  • Have a basic understanding of good circuit layout techniques for switching converters.
  • Be able to set up a dynamic model for mechanical system using Lagrange equation.


  • Have the ability to model and analyse a hydraulic servo system, thereby being able to set up performance criteria and identify performance limitations
  • Be able to design and implement linear controllers for hydraulic servo mechanisms and evaluate and validate the performance obtained
  • Have the ability to design, model and simulate a servo system based on either a DC machine or a square-wave brushless machine
  • Be able to design a closed-loop servo control system taking component limitations into account and to use a power electronic converter as part of the actuator system
  • Be able to design simple power electronic converters, including component selection and proper thermal management.

Type of instruction

The teaching is organized in accordance with the general form of teaching. Please see the programme cirruculum §17.

Extent and expected workload

Since it is a 5 ECTS course module the expected workload is 150 hours for the student.



Name of examControl of Fluid Power and Electrical Servomechanisms
Type of exam
Written or oral exam
Permitted aidsInformation about allowed helping aids for the examination will be published in the description of the semester/module.
Assessment7-point grading scale
Type of gradingInternal examination
Criteria of assessmentThe criteria of assessment are stated in the Examination Policies and Procedures

Facts about the module

Danish titleRegulering af hydrauliske og elektriske servomekanismer
Module codeN-EMSD-K1-2
Module typeCourse
Duration1 semester
Language of instructionEnglish
Empty-place SchemeYes
Location of the lectureCampus Aalborg
Responsible for the module


Education ownerMaster of Science (MSc) in Engineering (Mechanical Engineering)
Study BoardStudy Board of Energy, Study Board of Mechanical Engineering and Physics
DepartmentDepartment of Energy
FacultyThe Faculty of Engineering and Science