Design of Mechanisms and Robotics




  • March 2009 - February 2013



This research project is sponsored by Pieken in de Delta by order of the Dutch Ministry of Economic Affairs. BAS-number PID07038.


Tele-manipulation, endoscopic surgery, minimal invasive surgery, robotic surgery, NOTES, SILS


Surgical robotic systems are revolutionizing healthcare and medical services. Laparoscopy is becoming more invasive while conventional surgery is becoming less invasive. This has led to the emergence of the NOTES (Natural Orifice Transluminal Endoscopic Surgery) and SILS (Single Incision Laparoscopic Surgery) procedures, in which use of flexible instruments is essential. A robotic control of these instruments inside the body is both challenging and critical for achieving good surgical outcomes.

The TeleFLEX project is one of the initiatives of University of Twente to design, and develop a state-of-the-art surgical robotic system for endo-/transluminal endoscopic surgery, and carry out research on the enabling technologies. The master-slave concept, which is the norm in robotic surgery today and in robotic technology itself, can solve many of the technical challenges encountered in conventional flexible endoscopic surgery. The master side contains a master input device (e.g. a haptic device or a manipulator) with a controller and other visual display devices. The slave side includes an endoscope/ endoscopic platform, which provides access channels for the flexible surgical instruments and other accessories required for the particular intervention, controller and drive system.

Figure 1 shows the flexible endoscope with surgical tools used for experimental surgery. However, the control of flexible endoscope and the surgical tools requires control of many degrees-of-freedom at the same time requiring 3 to 4 surgeons around the patient making the operation costly and difficult to control.


Figure 1: Flexible endoscopes and experimental surgery using a flexible endoscope

Cost and quality can be improved by using a robotic manipulator (a slave) operated by a surgeon by means of a tele-manipulation system (a master). EndoSAMURAI consists of a visualization system, two end-effectors (each with five degrees of freedom), a third conventional working channel, and an ergonomic user interface (Figure 2). But there are still a lot of gaps before a complete tele-manipulation system for transluminal endoscopic surgery can be on the surgeon’s hand.


Figure 2: The EndoSAMURAI [1]


The objective of this project is to develop a tele-manipulation system for transluminal endoscopic surgery with intuitive control and optimal ergonomics with the capability of controlling flexible endoscope and various surgical tools.


Development of such a system requires collaboration from various disciplines within engineering and medical science. Understanding the requirements of surgeons and the efficacy of such systems in effecting the targeted interventions are of paramount importance. To realize the objective of TeleFLEX project, various groups from the university collaborated with industrial partners and formed a consortium.

The target intervention is identified based on the input obtained from surgeons and other medical professionals, who comprise the project user group. The target intervention is selected based on technical feasibility, the medical know-how available, safety, and number of occurrences reported in the hospitals. Mucosectomy was identified as the target intervention. Mucosectomy is a partial-thickness resection of the bowel wall. This technique is widely used for the curative treatment of superficial “early” cancers of the gastrointestinal tract. This is capable of completely removing the mucosal layer.

The mechanical behaviour of the flexible endoscope and of the surgical instruments can pose limitations in terms of controllability of such master-slave system. Unlike conventional endoscopic interventions, it requires motion and force inputs and outputs. The instrument tip may need to deliver certain amount of force or to orientate in particular way. The actuators and sensors are placed outside the body. The motion/force fidelity of the instrument is of paramount importance as it is critical for the overall performance of the master-slave system. Modelling and simulation of the flexible instrument can provide us the essential design parameters which are necessary for predictable input/output relationship for the instrument. It also provides the design specifications for the future instrument developments required for such interventions.


  • Survey on Surgical Robotics
  • Interviewed surgeons/experts (User Group – TeleFLEX) and compiled user requirements
  • State of the art: Flexible Endoscopic Surgery, Master Manipulator
  • Selection of focus intervention
  • Design and fabrication of FuMo1
  • Modelling and simulation of a flexible surgical instrument inside a curved rigid tube - Planar case
    • Effect of friction on motion hysteresis
    • Effect of bending rigidity of the instrument on motion hysteresis
  • Design and fabrication of reconfigurable and modular experimental set-up for measuring interaction forces and contactless measurement of the tip motion
    • Actuation module – 2-DOFs – translation and rotation along the longitudinal axis of the instrument at the proximal end
    • Force sensing module – 6-DOFs – measurement of interaction force and torque between the instrument and the guide tube
    • Tip motion measurement module – 2-DOFs – contactless measurement at the tip of the instrument – both translation and rotation along the longitudinal axis of the instrument at the distal end
  • Evaluation of the experimental set-up
  • Experimental validation of the developed model
  • Effect of the combined motion on the force transmission of a flexible instrument through a rigid curved tube
    • Analytical study
    • Modelling and simulation
    • Experimental validation


PhD Thesis (draft in-preparation)

  1. J.P. Khatait, Motion and Force Transmission of a Flexible Instrument Inside a Curved Endoscope, Ph.D. Thesis, University of Twente, Enschede, the Netherlands, draft in-preparation.

Master Thesis

  1. M. Krijnen, Modelling the friction induced behaviour of a guidewire in a guiding tube, Master thesis, University of Twente, June 2011, WA-1303.

Journal papers (refereed)

  1. J.P. Khatait, D.M. Brouwer, R.G.K.M. Aarts, & J.L. Herder (2013). Effect of combined motion on force transmission of a flexible instrument through a rigid curved tube, Journal of Medical Devices, draft in-preparation.
  2. J.P. Khatait, D.M. Brouwer, J.P. Meijaard, R.G.K.M. Aarts, J.L. Herder (2012). Flexible multibody modelling of a surgical instrument inside a curved endoscope, Journal of Computational and Nonlinear Dynamics, draft submitted, under review.
  3. J.P. Khatait, D.M. Brouwer, R.G.K.M. Aarts, J.L. Herder (2012). Design of an experimental set-up to study the behavior of a flexible surgical instrument inside an endoscope, Journal of Medical Devices, draft submitted, under review.
  4. J.P. Khatait, D.M. Brouwer, R.G.K.M. Aarts, J.L. Herder (2013). Modelling of a flexible instrument to study its sliding behavior inside a curved endoscope, Journal of Computational and Nonlinear Dynamics, Volume 8, Issue 3, 031002(2013), DOI:10.1115/1.4007539.

Conference proceedings (refereed):

  1. J.P. Khatait, D.M. Brouwer, R.G.K.M. Aarts, & J.L. Herder (2012). 3-D multibody modeling of a flexible surgical instrument inside an endoscope, ASME 2012 International Mechanical Engineering Congress & Exposition, November 9-15, 2012, Houston, Texas, USA.
  2. J.P. Khatait, D.M. Brouwer, R.G.K.M. Aarts, & J.L. Herder (2012). Test Set-up to Study the Behavior of a Flexible Instrument in a Bent Tube, ASME 2012 Design of Medical Devices Conference (DMD2012), April 10-12, 2012, Minneapolis, Minnesota, USA.
  3. J.P. Khatait, M. Krijnen, J.P. Meijaard, R.G.K.M. Aarts, D.M. Brouwer, & J.L. Herder (2011). Modelling and simulation of a flexible endoscopic surgical instrument in a tube, ASME 2011 International Mechanical Engineering Congress & Exposition, November 11-17, 2011, Denver, CO, USA.
  4. S. Kodandaramaiah, M. Krijnen, J. Go, S. Malik, J.P. Khatait, R.G.K.M. Aarts, D.M. Brouwer and C. Forest (2011). Characterization of translation of fused silica micropipettes in non-rectilinear trajectories, 26th Annual Meeting of the American Society for Precision Engineering, Sunday-Friday, November 13-18, 2011 Denver, CO, USA.
  5. J.P. Meijaard, Modelling and simulating the motion of a wire in a tube, EUROMECH colloquium 524, Multibody system modelling, control and simulation for engineering design February 27–29, 2012, University of Twente, Enschede, Netherlands
  6. J. P. Meijaard, R. G. K. M. Aarts, D. M. Brouwer, Modelling and Simulation of the Motion of a Slender Beam in a Tube, The 2nd Joint International Conference on Multibody System Dynamics, May 29–June 1, 2012, Stuttgart, Germany

Miscellaneous publications:

  1. J.P. Khatait, D.M. Brouwer, R.G.K.M. Aarts, & J.L. Herder (2011). Modelling of a Flexible Instrument and Design of a Test Set-up, Trade Fair & Conference, Precision Fair 2011, 30 Nov. & 01 Dec 2011, Veldhoven, Netherlands, poster and set-up demo as a part of 3TU Federation.
  2. J.P. Khatait (2009). Design of Master for Telemanipulation System for Endo-/ Transluminal Endoscopic Surgery, 4th Summer School in Surgical Robotics, September 09-16, 2009, Montpellier, France.


[1]. Georg O. Spaun, Bin Zheng, and Lee L. Swanstrom, A multitasking platform for natural orifice translumenal endoscopic surgery (NOTES): a benchtop comparison of a new device for flexible endoscopic surgery and a standard dual-channel endoscope, Surgical Endoscopy, published online on April 10, 2009.