About Me

I am a mechanical engineer, roboticist, researcher and innovator. I like robots and especially exoskeletons. I research, design and build fully functional exoskeleton devices and other robots. The bespoke technology ranges from mechanical components, power and control electronics to the underlying robot control software. Below you will find more information about my projects and links to my research publication. My research primarily focuses on the following two fields:

Novel exoskeleton devices:

Despite the efforts of the research community, significant progress is still needed before everyone can wear an exoskeleton. I research new exoskeleton mechanisms and solutions that are comfortable and lightweight, but also durable and reliable. I strive to make the exoskeleton device generally accessible and to achieve this goal, I explore new combinations of soft and rigid structures, new sensor and actuation technologies.

Mechanically Compliant Actuation:

Compliant actuation is central to all living things. The human musculoskeletal system combines muscles and tendons to enable running, jumping, throwing, etc. Mechanically Compliant Actuators mimic this structure by combining an electric motor with an elastic element. This combination offers many advantages similar to the performance of biological muscles. However, these advantages come at the cost of higher mechanical complexity. In my research, I look for new ways to mitigate these drawbacks of compliant actuation and to make these actuators easier to use and more robust.

My Research

UpperLimb Exoskeleton

This exoskeleton is aimed at assisting the upper limbs. Two motors placed on the user's back drive the Bowden cables to provide the necessary torque to the user's joints. This way, the exoskeleton compensates for the weight of the user's arm or the tool the user currently holds in his or her hand. The two videos on the right demostrate the proposed device.

With the motor and battery located in the back, the frame of the exoskeleton remains light and has minimal inertia. This also allows the exoskeleton to move faster and may help with faster tasks such as throwing and knocking. Additionally, the exoskeleton uses many components that are manufactured using traditional and additive manufacturing methods. While Bowden cables allow for lightweight frame designs, they worsen the overall friction and efficiency of the system. This research explores the use of Bowden cables and explores solutions to mittigate this problem. Aditionally, the exoskeleton system implements several redundant sensor architectures to explore alternative sensing techniques for both internal and external exoskeleton parameters.

The results of this research are published in:
   

Pronation & Supination Mechanism

This pronation & supination mechanism is an add-on module of the UpperLimb exoskeleton. The pronation/supination movement of the lower arm is critical for many everyday tasks such as opening doors, eating, etc. People who are unable to fully pronate & supinate their lower arms will have difficulty with these otherwise mundane tasks. The proposed mechanism assists in pronation and supination.

This research project explores a novel mechanism that relies on two rods, which are guided in two circular grooves. The cable drive allows the two rods to rotate. This causes the wrist to rotate. The mechanism offers a light weight alternative to other, often much heavier pronation/supination mechanisms that rely on large bearings, etc.

The results of this research are published in:
   

Elbow Exoskeleton

The Variable Stiffness Actuator (VSA) integrated in this exoskeleton relies on a novel stiffness variation mechanism which allows the stiffness of the mechanism to be adjusted. Often, there are tasks that require a specific stiffness for various reasons, such as maximising energy efficiency or rigid/soft movement strategies. In such cases, fast and energy-efficient stiffness adjustment is desirable. The proposed mechanism embodies these properties.

It uses two motors, one of which is larger and the other is smaller. The larger motor allows the external link to rotate and adjust its equilibrium position. The smaller second motor allows the stiffness of the mechanism to be adjusted. The second motor is much smaller than the main larger motor due to the energy efficient stiffness variation principle. An exoskeleton frame was also designed to explore the use of the new VSA as an exoskeleton actuator for the elbow.

This research is important since it demonstrates the existence of a new energy-efficient stiffness variation principle.

The results of this research are published in:
   
   
   

Passive Ankle Exoskeleton

This is a quasi-passive ankle exoskeleton. It can support the user while walking without relying on heavy motors or batteries.

It takes advantage of the fact that the calf muscle actually functions more closely to a clutch than to a classical muscle. The calf muscle locks and extends the Achilles tendon at a specific time of the normal gait cycle and store elastic energy. This is one of the mechanisms by which the body improves the efficiency of walking. However, the "clutch" of the calf muscle is actually an active clutch and not energy efficient. The quasi-passive exoskeleton exploits this deficiency by adding a mechanical clutch connected to an elastic element to the ankle joint. The use of an exoskeleton replaces the function of the calf muscle and Achilles tendon combination, reducing their effort. Assisting in this way may reduce the metabolic expenditure of the user by even up to 10%.

This is surprising because many exoskeletons require large motors and batteries to achieve such positive assistance effects.

The results of this research were published in:
   
   

Gallery

Funding

Awarded Fundings

  • 2019-2020 DAAD funding for short research stay in Germany, funded by “Deutscher Akademischer Austauschdienst
  • 2015-2019 Young researcher programme by Slovenian Research Agency (ARRS), core funding No. PR-06812

Other Funding Sources

  • 2021-.... JuBot: Staying young with robots - versatile robot assistance for coping with everyday life, Carl Zeiss Stiftung, Germany
  • 2020 Exosafe (A mechatronic leg replica to benchmark safety of human exoskeleton interaction), project by the COVR European Project under grant agreement No. 779966
  • 2020 Automation, Robotics, and Biocybernetics program group founded by Slovenian Research Agency (P2-0076)
  • 2019-2020 GOSTOP (Building blocks, tools and systems for factories of the future), Slovenian Research Agency