Vincent’s research videos

Doing scientific research is one thing, publishing and communicating the results is also very important. My scientific publications are listed here and we also created many video compilations in the different projects that I am involved in. Below is a more or less complete overview of the research videos (co-)created by me during my research at Robotics and Mechatronics, University of Twente.

The embedded videos are all hosted on my Vimeo channel (ad-free!). My research group has a YouTube channel (with ads, unfortunately) and I also have a YouTube channel myself.

Total 31 video compilations. Per year: (2022:) 5, (2021:) 5, (2020:) 3, (2019:) 5, (2018:) 4, (2017:) 2, (2016:) 4, (2015:) 2, (2014:) 1.

Of these 31 compilations 26 were edited by myself; 5 by project students or colleagues.

Many compilations have music and/or voice-over. Most of these were composed/spoken by Tim de Man.


Absolute Position Detection in 7-Phase Sensorless Electric Stepper Motor

To be presented at IROS 2022 in Kyoto, Japan.

Sunram 7 draft video

This robot is the 7th generation robotic system for MRI-guided breast biopsy. Main improvements include a novel motor design for better robustness and printability, and various calibration options.

(A proper compilation with voice-over etc is under development.)

Pneumatic Turing Machine: Main compilation

Can you 3D print a Turing-complete computer which runs on pressurized air? Yes! Although the number of states and bits is somewhat limited in this prototype.

First demonstrated at European Robotic Forum 2022, Rotterdam, The Netherlands.

The 4/2-way valve component can be downloaded at Printables. More components will be published later.

Pneumatic Turing Machine: Addition

Demonstrates calculation of 2+1, and 3+5. The numbers are not binary encoded, but specified by a consecutive number of 1’s followed by a 0.

(Supplementary video to the main Pneumatic Turing Machine compilation)

Pneumatic Turing Machine: Busy Beaver

Demonstrates 2-state and 3-state Busy Beaver. These are special programs for a binary Turing machine which gives the maximum possible output given the number of available states.

(Supplementary video to the main Pneumatic Turing Machine compilation)


Multi-axis Electric Stepper Motor

The three output shafts are independently actuated by a single stator.

YouTube link

Six-axis pneumatic stepper motor

The motor is driven by four cylinders using only five pneumatic lines in total. Each of the six output shafts have a positioning accuracy of 2 steps. This is a consequence of the design with shared cylinders.

Robot-Guided Translation of a Preoperative 3d Planning During Open-Vault Reconstruction of Craniosynostosis

Project by Anouck Pilon, Eva Koot, Rémi van der Woude, Lisanne Venix. Supervised by Vincent Groenhuis et al.

Multidisciplinair project (MDO), as part of BSc Technical Medicine.

Link to essay abstract

Next-gen in-vivo: early concepts

It shows a scale model of a cystoscope with camera, inertial unit, lights and dummy optical coherence tomography (OCT) sensor.

More information about the Next-gen in-vivo project can be read here.

Image-guided Breast Biopsy of MRI-visible Lesions with a Hand-Mounted Motorised Needle Steering Tool

MSc project by Marta Lagomarsino, supervised by Vincent Groenhuis et al.


Control and design of 3D printed biopsy robot using mobile application

BSc project Mart Bluiminck, supervised by Vincent Groenhuis et al.

Link to essay

Final compilation of the MURAB project

MURAB: MRI and Ultrasound Robotic Assisted Biopsy

The project did run from 2016-2020.

Website / YouTube link

MURAB technical video

This video shows several steps in the workflow such as path planning, ultrasound scanning, 3D ultrasound reconstruction, biopsy planning, needle insertion and sample validation. Deformations of soft tissue are taken into account.


Miniaturization of MR Safe Pneumatic Stepper Motors

Presented at IROS 2019, Macau

YouTube link

MURAB workflow video as demonstrated at Hamlyn Surgical Robot Challenge 2019. We also demonstrated the physical robot and clinical workflow in London.

Universal Auto-Rewind Spool Holder

Although a hobby project, a combination of this device and Sisyphus spool holder are currently used at RaM for feeding one of our multi-material 3D printers.

Thingiverse link for 3D files and instructions.

Pneumatic Screwdriver

A hobby project using pneumatic stepper motor technology developed at RaM.

Thingiverse link for 3D files and assembly instructions

CatchBot: A Versatile MR Safe Robotic Platform for Image-Guided Endovascular Interventions

Research primarily conducted by Mohamed E.M.K. Abdelaziz. The robot uses practically the same pneumatic stepper motors as in the Sunram 4.

YouTube link


Pneumatic Bourke Engine

This is actually a hobby project, using pneumatic stepper motor technology developed at RaM.

3D printable parts can be downloaded here.

Pneumatic Gripper

A hobby project, again using pneumatic stepper motor technology developed at RaM.

3D printable parts can be downloaded here.

Sunram 5: An MR Safe Robotic System for Breast Biopsy.

Improvements over Sunram 4 include dual-speed motors, a biopsy gun, an emergency needle ejection feature and a curved rack for better angulation of the needle towards the breast.

YouTube link

Dual-speed MR Safe Pneumatic Stepper Motors

Presented at Robotics: Science and Systems (RSS) in Pittsburgh, United States


Sunram 4: An MR Safe Robotic System for Breast Biopsy.

This won the “Best Video” award at Hamlyn Surgical Robot Challenge, London. Over 130 articles (in 16 languages) about this robot appeared online.

The robot has a serial kinematic chain, as opposed to a parallel kinematic chain in the previous iteration.

YouTube link

Visualization of breast phantom and lesions with Hololens

BSc project by Leon Klute, supervised by Vincent Groenhuis.

The needle is tracked using either a stereo camera or an NDI electromagnetic tracker (from 0:31), and visualized in the scene together with the phantom and lesion(s) using augmented reality.

Link to BSc report


Sunram 3: An MR Safe Robotic System for Breast Biopsy

This robot won the “Best Design” award at Hamlyn Surgical Robot Challenge, London.

Main improvements over Sunram 2 are better motors and overall design, and somewhat larger workspace.

YouTube link

High-Performance Pneumatic Stepper Motors

Two linear and three rotational stepper motors are demonstrated, all 3D printed and quite powerful for its size.

YouTube link (18K+ views), RaM YouTube link

MURAB end-effector concept

MSc project by Ruud Spoor, co-supervised by Vincent Groenhuis et al.

The needle holder has the special safety feature that the links are magnetically connected and can be detached easily in case of emergency.


Controlling the Sunram 2: An MR Safe Robotic System for Breast Biopsy

MSc project by Mohamed E.M.K. Abdelaziz, supervised by Vincent Groenhuis et al.

YouTube link


Sunram 2: An MR Safe Robotic System for Breast Biopsy

YouTube link

Sunram 1: first iteration of MR safe robotic system for breast biopsy

YouTube link


Powered Exoskeleton

Internship project at University of Canterbury, Christchurch, New Zealand

Specifications of pneumatic stepper motors and rotary engines

Many pneumatic stepper motors, rotary engines and other pneumatic devices were developed during our research. Several were published in research papers and/or 3-D model websites. This page lists nearly all of them, alongside with the most important properties and a link to the downloadable model (if available). If a motor design is not yet downloadable then you can send me a request for it.

Certain motors have extensive printing and assembly instructions and/or a video compilation. If you are interested in 3-D printing one of these motors then there should be plenty of information and designs to start with.

At the moment I subdivided the motors into five categories: linear, rotational, curved, rotary engine and dual. The motor name consists of a character (or two in case of dual-speed) plus a number and sometimes a postfix.

First character(s): T=linear, R=rotational, C=curved, D=dual. The following number indicates the major dimension (length or diameter) of the motor, in mm. The “B” postfix indicates a redesign of an existing model.

In theory it is possible to scale any design along (some combination of) its axes. This should work with some experimentation.

If you need help with a motor then you can post a comment on the associated Thingiverse or MyMiniFactory webpage, and I will look into it. You can also contact me directly at If you designed something cool based on these designs then I am always happy to see it!

Designs are for non-commercial use only. Contact me for IP related questions.

Linear, rotational and curved stepper motors

More stepper motors and rotary engines

Linear stepper motors

Rotational stepper motors

Rotary engines (continuously-rotating motors)

Curved stepper motors

Dual-speed motors

Multipurpose stepper motors

NameSize (mm³)StepsForce/TorquePiston size (mm²) Link
M-4545 x 40 x 156.9°, 5.3°0.5 Nm120PA