PhD - MIMO closed-loop control for Directed Energy Deposition of Functionally Graded Materials

1 - Working at the VUB

For more than 50 years, the Vrije Universiteit Brussel has stood for freedom, equality and solidarity, and this is very much alive on our campuses among students and staff alike. 

At the VUB, you will find a diverse collection of personalities: innovators pur sang, but above all people who are 100% their authentic selves. With some 4,000 employees, we are the largest Dutch-speaking employer, in the private sector, in Brussels; an international city with which we are only too happy to connect and where (around) our 4 campuses are located. 

Add to this our principle of free research - in which self-reflection, a critical attitude and an open, creative mind around scientific and social issues are central - and you have a university that is fundamentally groundbreaking and pioneering in education and research. In short: the VUB all over again. 

Moreover, the VUB is a member of EUTOPIA, an alliance of like-minded European universities, all ready to reinvent themselves.

2 - Position description

The Faculty of Engineering, Department Toegepaste mechanica, is looking for a PhD-student with a doctoral grant. 

More concretely your work package, for the preparation of a doctorate, contains: 

The Mechanical Engineering department at the Vrije Universiteit Brussel (VUB) is looking for a motivated PhD candidate who wants to contribute to groundbreaking research into the optimisation of the laser-based, powder-controlled Directed Energy Deposition process (DED-LB) for metallic Functionally Graded Materials (FGMs). This advanced additive manufacturing technique allows complete three-dimensional design freedom by locally adjusting material properties through real-time modifications of the powder composition. In steels, local thermal gradients also influence phase formation, making accurate process control essential. The research focuses on developing strategies to control the temperature, geometry and composition of the melt pool, with the aim of achieving defect-free production of FGMs. Such high-performance components are expected to outperform conventional single-alloy parts, eliminate design compromises and deliver superior performance in demanding applications.

The DED-LB research platform at the VUB was conceived, designed and built entirely in-house with an open architecture, offering maximum flexibility for the integration of new functionalities. Over the years, it has been systematically improved with the ambition of advancing the state of the art in Directed Energy Deposition. In addition to advanced thermal monitoring instruments (such as hyperspectral and SWIR cameras), new techniques for composition monitoring will also be integrated into this PhD. Thermal prediction models are currently implemented on a Field Programmable Gate Array (FPGA), while the thermal PI controller (which will be further developed) runs on the system's PLC. Therefore, prior knowledge of PLC and FPGA programming is considered a strong asset.

You will design, implement and evaluate a multi-input multi-output (MIMO) closed-loop process controller for the DED-LB process, capable of controlling the complex and dynamic conditions of metallic FGMs. Thermal gradient control will be achieved by simultaneous adjustment of laser power and scan speed. In parallel, the fabrication of composition-graded structures requires combined control of laser power, scan speed and powder feed ratios, continuously responding to the changing process dynamics resulting from varying compositions. An adaptive Model Predictive Control strategy is envisaged for this challenge.

During the four-year doctoral programme, you will contribute to the group's R&D activities in the following areas:

· Selection, integration and calibration of thermal and composition sensors for melt pool monitoring in advanced DED-LB process control
· Implementation of thermal (gradient) estimators on an FPGA, as real-time input for the control system
· Development of state space and system identification models of the DED-LB process, with emphasis on composition effects in the melt bath
· Design, implementation and validation of a MIMO controller for both thermal gradient control and combined temperature–composition control
· Fabrication of metallurgical test specimens for quality assessment, demonstrating the impact of advanced process control on FGMs
· Possible collaboration with ongoing research, including validation of numerical models, reduction of residual stresses through thermal management, and machine learning approaches for process monitoring and control

For this function, our Brussels Humanities, Sciences & Engineering Campus (Elsene) will serve as your home base. 

3 - Profile

What do we expect from you?

• You have a master's degree in Control/Electrical or Mechanical Engineering.

• Motivated to become an expert in additive manufacturing, advanced process control and (optical) measurement techniques.
• Practical skills to carry out experimental work, implement monitoring solutions and make hardware adjustments to the research platform.
• A strong background in system control; previous experience with thermal/compositional monitoring and process control is considered a strong asset.
• Basic skills in Matlab and/or Python for data collection, processing and presentation; experience with PLC and/or FPGA programming is an additional advantage
• Previous experience with the following topics is considered a plus: additive manufacturing, monitoring of melting processes, implementation of controllers, (optical) measurement techniques, PLC and FPGA programming, machine integration, etc.

• You have not performed any works in the execution of a mandate as an assistant, paid from operating resources, over a total (cumulated) period of more than 12 months.

• As a (non-)EEA national, meet the conditions for obtaining a valid permit for VUB and comply with the VUB residence requirements. More info here.

The VUB wants to be a reflection of the society where everyone's talent is valued, regardless of gender, age, religion, skin color, migration background, disability and neurodiversity.

4 - Offer

Are you going to be our new colleague?

You’ll be offered a full-time PhD-scholarship, for 12 months (extendable up to max. 48 months, on condition of the positive evaluation of the PhD activities), with planned starting date 01/01/2026. 

You’ll receive a grant linked to one of the scales set by the government.

IMPORTANT: The effective result of the doctorate scholarship is subject to the condition precedent of your enrolment as a doctorate student at the university.

At the VUB, you’re guaranteed an open, involved and diverse workplace where you are offered opportunities to (further) build on your career.

As well as this, you will also enjoy various other benefits:

• Extensive homeworking options, a telework allowance of 50 euros per month OR an internet fee of 20 euros per month;
• An open and informal working environment where attention is paid to work-life balance, and exceptional holiday arrangements with 35 days of leave (based on a fulltime contract), closure between Christmas and New Year and 3 extra leave days;
• Cost-free hospitalisation insurance;
• Full reimbursement of your home-to-work commute with public transport according to VUB-policy, and/or compensation if you come by bike; 
• A wide selection of meals in our campus restaurants at attractive prices;
• Excellent and affordable facilities for sport and exercise, a range of discounts via Benefits@Work (in  all kinds of shops, on flights, in petrol stations, amusement parks...) and Ecocheques; 
• Nursery near campus, discount on holiday camps; 
• The space to form your job content and to continuously learn through our VUB learning platforms and training courses;
• And finally: great colleagues with a healthy drive.

5 - Interested?

Is this the job you’ve been dreaming of?

Then apply, at the latest on 01/11/2025, via jobs.vub.be, and upload the following documents:

• your CV;
• your motivation letter;
• your diploma (not applicable for VUB alumni).

Our application process is as follows (subject to change):

• step 1: an initial selection based on your application file; 
• step 2: a job interview.

Do you have questions about the job content? Contact Michaël Hinderdael at michael.hinderdael@vub.be or on +32 2 629 28 07.

Would you like to know what it’s like to work at the VUB? Go to jobs.vub.be, and find all there is to know about our campuses, benefits, strategic goals and your future colleagues.

Would you like more information about EUTOPIA? Go to eutopia-university.eu, and read more about the role of the VUB in the development of the EUTOPIA alliance.