NUS S&T Exhibition Launch at UCC

(9 April 2015) We have been invited to demonstrate our Intelligent Tubular Robotic System (iTubot) at the exhibition showcasing NUS’ contribution to nation-building through groundbreaking research. The event launched at the University Cultural Centre on 9 April to celebrate the 50th birthday of Singapore and the 110th birthday of NUS.

Our Intelligent Tubular Robotic System can potentially assist with minimally invasive procedures and is also endowed with intelligent navigation capabilities, which receives much attention during the event.



Useful Checklists/Guides to Improve Research Skills

Useful Checklists/Guides (Selected)

  • How to undertake a literature search and review: for dissertations and final year projects [PDF]
  • Writing the Literature Review / Using the Literature [PDF]
  • Referencing: Why, when and how [PDF]
  • Minor thesis & research report structure [PDF]
  • Features of good reports [PDF]
    • A checklist for effective reports [PDF]
  • Undergraduate research report [PDF]
  • Oral presentations [PDF]

Useful Checklists/Guides (General ones):

  • 1. Research Proposal and Formulation:
    • Generating ideas & forming a question (University of Reading) [PDF]
  • 2. Reading Skills:
  • 3. Literature Review:
    • Getting Started on Your Literature Review (UNSW) [PDF]
    • How to undertake a literature search and review: for dissertations and final year projects (DMU) [PDF]
    • Literature Review: Academic Tip Sheet (Edith Cowan University) [PDF]
    • Literature review (tutorial) [RMIT]
    • Writing a Literature Review (UNSW) [PDF]
    • Writing the Literature Review / Using the Literature (RMIT) [PDF]
  • 4. Referencing:
    • Chicago Author-Date Referencing (Curtin University) [PDF]
    • Havard System (Bournemouth University) [PDF]
    • The Harvard system of referencing (DMU) [PDF]
    • Referencing: Why, when and how (Lincoln University) [PDF]
  • 5. Report/Thesis Organisation & Planning:
    • A Report Checklist (Lincoln University) [PDF]
    • Features of good reports (University of Reading) [PDF]
    • Minor thesis & research report structure (RMIT) [PDF]
    • Structuring your report (University of Reading) [PDF]
    • Undergraduate research report [PDF]
  • 6. Report/Thesis Writing:
    • Abstract Preparation Guidance (HKU Graduate School) [website]
    • Paraphrasing, Summarising & Quoting (UNSW) [PDF]
    • Writing a research report (RMIT) [PDF]
    • Writing critically?(Lincoln University) [PDF]
  • 7. Oral presentations:

Communication Skills:

  • Guidelines for Effective Oral and Written Communications [PDF]
  • Making a Presentation [PDF]
  • Engineering an Effective PowerPoint Presentation [PDF]
  • Mastering Technical Writing [PDF]
  • Scholarship and Intellectual Property [PDF]

Literature Search and Review Skills:

Presentation Skills:

Project Management:

Research Skills:

Writing Skills:


Two projects won awards from Asia Pac AR&TTs challenge 2015

(Mar, 2015) In the recent Asia Pac AR&TTs challenge 2015, our project on a soft robotic system for oral intervention (team members: Neera, Yi, Hongliang) won the Commercial Potential Award and the project on magnetic actuated robotic intervention (team members: Shen Shen, Zhu Jingling, Song Shuang, Li Jun, Loh Kai Ting, Ren Hongliang) won the Pitching Award.



BN5209 Neurosensors and Signal Processing AY14/15

BN5209 Neurosensors and Signal Processing Semester 2, 2014/2015


Time period: 14-Jan-14 To 9-May-14
Lecture Time:

  • Tuesday: 5 pm – 7 pm (E3-06-04)
  • Friday: 5 pm – 7 pm (EA-06-03)


  • Week 1: Jan 13,16
    Intro to the Course (NT,HR)
    Intro to Neurosciences (NT)
  • Week 2: Jan 20,23
    Neural recording methods: Microelectrodes, MEMS, optical neuro sensors (NT)
  • Week 3: Jan 27,30
    Neural recording methods: Neural circuits, amplifiers, telemetry, stimulation (NT)
  • Week 4: Feb 3,6
    Introduction of BioSignal Processing (HR)
  • Week 5: Feb 10,13
    Prepare Student Seminars – paper selection
    Time-Frequency-Spatial Analysis STFT (HR)
  • Week 6: Feb 17, 20(holiday)
    Neural signals (clinical applications)- EEG, evoked potentials (HR)
    Lab tutorial for Project I: Neural Signals and Analysis
  • Recess Week Sat, 22 Feb 2014 ~ Sun, 2 Mar 2014
  • Week 7: Mar 3,6
    Multiple Dimensional Signal Processing (HR)
    Lab Project II: Application in neural systems
  • Week 8: Mar 10,13 (eLearning)
    Student Reading Seminars 5209 (HR)
    Student Reading Seminars 6209 (NT,HR)
  • Week 9: Mar 17,20
    Brain machine interfaces (NT)
  • Week 10: Mar 24,27
    BMI- Neural Spikes (NT)
    Optical imaging: Cellular (microscopy), In Vivo (Speckle, Photoacoustic, OCT) (NT)
  • Week 11: Mar 31, Apr 3
    Neuroimaging and Image Processing (HR)
    Neuroimaging fMRI (HR)
  • Week 12: Apr 7,10
    Advanced Neurosignal Processing / Neurosurgical systems (HR)
    Applications of neural signal processing (HR)
  • Week 13: Apr 14,17
    Project Reports (due before final)/presentations (HR, NT)

Course Projects

1. EEG for brain state monitoring
2. EEG/EMG Feature Identification during Elbow Flexion/Extension


This module teaches students the advanced neuroengineering principles ranging from basic neuroscience introduction to neurosensing technology as well as advanced signal processing techniques. Major topics include: introduction to neurosciences, neural recording methods, neural circuits, amplifiers, telemetry, stimulation, sensors for measuring the electric field and magnetic field of the brain in relation to brain activities, digitization of brain activities, neural signal processing, brain machine interfaces, neurosurgical systems and applications of neural interfaces. The module is designed for students at Master and PhD levels in Engineering, Science and Medicine.


Basic probability
Basic circuits
Linear algebra (matrix/vector)
Matlab or other programming
Recommended Textbooks: Neural Engineering, Edited by Bin He
Seminar papers


The majority of the course will be in lecture-tutorial format. Some advanced topics will be in the formats of seminar and research presentations.


Take Home Tests (5 for 50%)
Labs/Projects Reports + Presentations (2 for 20%)
Seminars (1 for 10%)
Take Home Final Exam(20% )

IVLE Registration and Information


Lectures and Guest Lectures



This is a local copy of the website:

Home-Based Self-Administered Nasopharynscopy

Nasopharynscope is a valuable tool in diagnosing Nasopharyngeal carcinoma in patients since 84% of patients display ulcerations.

Aim: To provide a home-based, affordable and easy-to-use diagnosing kit for detecting Nasopharyngeal Carcinoma

Key features of 5th Generation

  • Clear viewing with a specially designed camera lens
  • Secure extension and contraction lock
  • Tight fit between nylon strings to ensure good power transmission 
  • Diamond cuts to enhance bending capabilities
  • Optical zoom of up to 5 mm due to shooting mechanism

Bending Capability: >90 degrees

Extension and contraction to evade obstacles

Overall Demonstration of Bending and Zooming capability


  • Outer Diameter: 7 mm
  • Length of extension portion:25 mm
  • Length of bending segment: 25mm
  • Minimum inserted length: 11-15 cm
  • Gear box: 30 by 20 by 30mm
  • Bending angle: 90 degrees bend per side
  • Distal tip mechanism: Optical zoom
  • Material: Polyurethane (Biocompatible)
  • Stent design: Flexibility
  • Flexible guiding tube

Technical Advantages

  • Large bending angle
  • Extending the camera using the spring mechanism to obtain better optical viewing up to 5mm
  • Endoscope is very flexible with the stent design
  • Able to control the bending of the body segments using cable driven mechanism
  • The bending of the endoscope at the entrance can be controlled flexibly by the guiding shaft


From Left: Mr Teo Jing Chun, Dr Ren Hongliang, Mr Un Weiyang, Miss Soh Yan Bing, Mr Ong Jun Hao Edmund
Foreground: Mr Yeow Bok Seng

BN 3101 IVLE Announcements

BN 3101 IVLE Announcements

Note: For your convenience, the following announcements are exactly extracted from IVLE and a PDF version is also attached here: IVLEAllAnnouncements.pdf

by: Aneel Kumar Maheshwari, 31-Oct-2014 11:19 AM.

IVLE: BN3101: BN3101 Director’s Award 

Dear students,This award is given to the group that shows that this module has a significant impact in the working relationship of the group and the learning process of the individual team members.How is this Award being judged?
Each group is to submit a one page write-up of less than 500 words on how this module has benefited the group in general and how it has changed individual members’ views on design of medical device. A general description of your experience would be most appropriate.You will be judged by: 
Your mentors’ perception of the positive impact this course has on your education and your relationship with your peers.Submit by: 
10:00am Monday the 03 Oct 2014.
Please send to Dr. LEO Hwa Liang ( with the following subject title:
BN3101 – Director’s Award Group X
where X is your group number.
Will we be graded on the write-up?
No, you will not be graded on this write-up.  This is an optional submission by the group.
Will any of the awards affect my grade?
None of the awards will affect your grades.
Aneel Kumar
by: Aneel Kumar Maheshwari, 31-Oct-2014 09:44 AM.

IVLE: BN3101: Reminder: submit team Presentation (20min and 5min) onto IVLE Final oral Presentation 

Dear BN3101 Studens:Reminder to submit your team presententation ( 20 mins + 5 mins ) onto IVLE Final oral Presentation folder  by 23:59 Sunday, 2nd Nov 2014.Regards,
Aneel Kumar
by: Aneel Kumar Maheshwari, 28-Oct-2014 03:32 PM.

IVLE: BN3101: BN3101 Oral Presentation Room Booking (Morning and After session)

Presentation to the individual supervisor in individual classroom (morning):EA-02-11 (9am to 12pm): Dr. Leo Groups (12-13)
EA-02-14 (9am to 12pm): Prof. Casey Chan Groups (1-3)
E1-06-04 (9am to 12pm): Dr. Ren Hong Liang Groups (4-6)
E1-06-06(9am to 12pm): Dr. James Kah Groups (7-9)
E1-06-14 (9am to 12pm): Dr. Michael Girard Groups (10-11)Schedule for the Final Afternoon Presentation for top teams
Announce the top team ONLY then. Start at 1:30pm – 2:15pm EA-02-11Refreshment:
2:15pm to 2:30pmPresentation of awards:
by: Aneel Kumar Maheshwari, 28-Oct-2014 02:58 PM.

IVLE: BN3101: BN3101 Final Oral Presentation (03 Nov 2014 on Monday)

Presentation to the individual supervisor in individual classroom (morning):1. Each team present 20 mins + 5-10 mins Q&A. Each presentation may divide the presentation in two or three sections.  Please submit onto IVLE Final oral Presentation folder by 23:59 Sunday 2ndNov the following list:The students are allowed to decide how many sections are there in their presentation and which section they want to present in.
For two sections:
First Section – 1st Member, 2nd Member, 3rd Member
Second Section – 4th Member, 5th Member, 6th Member
For three sections:
First Section – 1st Member, 2nd Member
Second Section – 3rd Member, 4th Member
Third Section – 5th Member, 6th Member
For teams having less than 6 members, any of the sections may have one member less.  The presenter will be announced at the time of presentation.
Guidelines for presentation:
Your presentation must conform to the following:
a. Each group is strictly given 30 min inclusive of Presentation (20 min), Q & A (5-10 min), and Change over (1 min).
b. When your .ppt file is ready, you may upload it onto the IVLE Final Oral Presentation folder
c. Your .ppt file must be submitted by 23:59 Sunday 2nd Nov.
d. You are to submit a 20 minutes presentation power point and 5 minutes abbreviated presentation (in case you are the finalist for the afternoon session).
e. All .ppt file must conform to the following format:
Group X 30 mins Presentation.ppt (X is the Group Number)
Group X 5 mins Presentation.ppt
The 5 minutes presentation in the afternoon should not include video.  For presentation to the individual supervisors, please check with your individual supervisor whether video can be included in the presentation.
Schedule for the Final Morning Presentation
The sequence of presentation will be up to the supervisor to decide.
Suggested start time 9:00 am and end around 12:00pm in individual classroom
Schedule for the Final Afternoon Presentation for top teams
Student can decide who to present.
Announce the top team ONLY then. Start at 1:30pm – 2:15pm EA-02-11
2:30pm pm Presentation of awards (15 minutes)
The following prizes will be given out:
1. Most Innovative Design
2. Most Elegant Instrumentation (Aesthetic and Ergonomic)
3. Most Fundable Design
4. Best Presentation
5. The Prestigious Director’s Award (voted by lecturers and mentors)
The winners of ‘Most Innovative Design’, ‘Most Elegant Instrumentation (Aesthetic and Ergonomic)’ and ‘Most Fundable Design’ will be chosen by means of votes casted by the students, lecturers and mentors. These awards are not graded
3pm Refreshments and Interaction session
All team members must be present throughout their afternoon session Final Presentation (Top 5 finalist).  Attendance will be taken and 0.5 points will be deducted for each team member absent during their respective sessions.  You are welcome to attend part or all of the other sessions.
Reports Submission
All teams have to submit the hard copy reports after the final presentation itself (Friday, 14th November 2014 before 5pm) to Aneel Kumar (Bio-design Lab E3-05-05). A penalty of 1 point will be imposed for each day of late submission of individual report. Please submit soft copy of your report and actual prototype to your respective supervisor.
Aneel Kumar
by: Aneel Kumar Maheshwari, 27-Oct-2014 03:18 PM.

IVLE: BN3101: Peer Assessment 2014

Dear BN3101 Students,The peer assessment exercise is conducted for students to assess their group members’ individual contribution to the project. For each review item you can grade your fellow group members from 0 to 10 by following a general marking standard of:0 = extremely poor;
6 = average;
8 = good;
10 = excellent.To do the peer assessment, please follow the steps of: go to the BN3101 IVLE webpage –> click Project –> click View –> click Project Evaluation (on the left) –> Select Peer Assessment 2014 –> click  Evaluate –> Evaluate your other group members one by one.Please do not routinely assign a high score as this will result in an average score for everyone. For this to work you have to give an honest assessment of your peers. The purpose of the peer assessment is to make minor adjustment within the group.
Your peer assessment rating will not affect other groups. And the rating by individual students is confidential and will not be made known to other group members.
Please complete the Peer Assessment 2014 by 14th Nov 2014 (Friday), 11:59pm; failure to do so, your group members’ project marks based on “team effort” will be affected.
Aneel Kumar
by: Leo Hwa Liang, 09-Oct-2014 04:15 PM.

New Files in Workbin – BN3101 : BIOMEDICAL ENGINEERING DESIGN – 2014

New Files :
Folder Name : Lecture NotesFilename: Bioethics and Medical Device.pdf
Description: BN3101 – Bioethics and Medical DevicesClick on the filename to download the file.
by: Leo Hwa Liang, 03-Oct-2014 09:32 AM.

New Files in Workbin – BN3101 : BIOMEDICAL ENGINEERING DESIGN – 2014

New Files :
Folder Name : Lecture NotesFilename: Sterility 2014.pdf
Description: BN3101 – SterilityFilename: GMP-GLP 2014.pdf
Description: BN3101 – GMP – GLPClick on the filename to download the file.
by: Leo Hwa Liang, 22-Sep-2014 09:02 PM.

New Files in Workbin – BN3101 : BIOMEDICAL ENGINEERING DESIGN – 2014

New Files :
Folder Name : Lecture NotesFilename: Quality_System_Template_2014.pdf
Description: BN3101 – Quality templateClick on the filename to download the file.
by: Leo Hwa Liang, 12-Sep-2014 11:53 AM.

New Files in Workbin – BN3101 : BIOMEDICAL ENGINEERING DESIGN – 2014

New Files :
Folder Name : Lecture NotesFilename: Review of Regulatory Issues 2014.pdf
Description: BN3101 – Regulatory Affairs lectureClick on the filename to download the file.
by: Leo Hwa Liang, 08-Sep-2014 12:21 PM.

IVLE: BN3101: BN3101 – Accessing ASTM standards in NUS central library

Dear ASTM students,NUS central library hold the ASTM standards, in hardbound (1998 and before) and DVD formats. You will need to sign in for the access of these standards. Remember to bring your thumbdrive to copy the relevant standards.You will not be able to access and download the ASTM standards from the internet as we need to pay to do so.Regards,
by: Leo Hwa Liang, 08-Sep-2014 10:56 AM.

New Files in Workbin – BN3101 : BIOMEDICAL ENGINEERING DESIGN – 2014

New Files :
Folder Name : AssignmentsFilename: ASTM Assignments 2014.pdf
Description: BN3101 – For ASTM students only, ASTM assignmentsClick on the filename to download the file.
by: Leo Hwa Liang, 04-Sep-2014 09:22 AM.

New Files in Workbin – BN3101 : BIOMEDICAL ENGINEERING DESIGN – 2014

New Files :
Folder Name : Lecture NotesFilename: Introduction to the ASTM 2014.pdf
Description: BN3101 – ASTMClick on the filename to download the file.
by: Casey Chan (Ortho), 01-Sep-2014 09:53 PM.

IP Lecture II

There is a live lecture on Monday 8 Sept from 10am to 12 noon at EA 02-11.Please see
by: Leo Hwa Liang, 29-Aug-2014 04:04 PM.

New Files in Workbin – BN3101 : BIOMEDICAL ENGINEERING DESIGN – 2014

New Files :
Folder Name : Lecture NotesFilename: Risk Management 2014.pdf
Description: BN3101 – Risk managementFilename: Design Rationale and Design Verification 2014.pdf
Description: BN3101 – Design Rationale and Design VerificationClick on the filename to download the file.
by: Leo Hwa Liang, 29-Aug-2014 03:59 PM.

New Files in Workbin – BN3101 : BIOMEDICAL ENGINEERING DESIGN – 2014

New Files :
Folder Name : Lecture NotesFilename: Risk Analysis Table.docx
Description: BN3101 – Risk analysis tableClick on the filename to download the file.
by: Leo Hwa Liang, 25-Aug-2014 04:44 PM.

New Files in Workbin – BN3101 : BIOMEDICAL ENGINEERING DESIGN – 2014

New Files :
Folder Name : Lecture NotesFilename: Design Analysis Tutorial.pdf
Description: BN3101 – Design Analysis slidesClick on the filename to download the file.
by: Aneel Kumar Maheshwari, 21-Aug-2014 12:00 AM.

Design Analysis Exercise ( Divided in Two time Slots)

Dear BN3101 Students,Design Analysis Exercise will be divided into two time Slots.Slot 1: (Group 1 – Group 7) and time :  1pm to 2pm on 25 August 2014 at EA-02-11
Slot 2: (Group 8 – Group 13) and time: 2pm to 3pm on 25 August 2014 at EA-02-11Reagrds,
Aneel Kumar
by: Aneel Kumar Maheshwari, 20-Aug-2014 12:00 AM.

BN3101 booking of machines in the design studio

Dear BN3101 supervisors,This semester both BN3101 and BN2103 will be using the Design Studio.To avoid problems, we set up an online booking system accessible (within NUS or VPN) at:
This applies to all the “workshop” machines in the lab like mill, lathe, saw, etc (not the Instron).
Please let your students know that if they want guaranteed time on the machine they will need to book. Students who booked the machine will have top priority in using the machine during the booked time slot.
The following restrictions on bookings apply (the system automatically detects violations of the rules ):
– Each single booking can last no more than 2 hours
– Each student can book a maximum of 4 hours per week per machine
Each BN3101 group will have an account with username BN3101_X (where X is the group number). Password is the same as the user name. Students may change it from the system later if they want to.
Kindly contact with Aneel, so he can creates the account for your groups.
Dr. Leo
by: Michael Girard, 12-Aug-2014 04:31 PM.

New Files in Workbin – BN3101 : BIOMEDICAL ENGINEERING DESIGN – 2014

New Files :
Folder Name : Groups 10-11Filename: BN3101 Iris Expander – Groups 10-11.pdf
Description: For Groups 10&11: Iris Expander – Project Description and General InfosClick on the filename to download the file.
by: James Kah, 11-Aug-2014 03:36 PM.
New Files in Workbin – BN3101 : BIOMEDICAL ENGINEERING DESIGN – 2014

New Files :
Folder Name : Group 7 to 9Filename: 140809 Consumer Diagnostics – Project Introduction.pptx
Description:Filename: BN3101-Timetable_2014.xls
Description:Filename: Quality_System_Template_2012.pdf
Description:Click on the filename to download the file.
by: Casey Chan (Ortho), 11-Aug-2014 12:00 AM.
IP Lecture I
This is the first of two lectures on Intellectual Properties.  The link for the lecture and the accompanying notes is here. The 2nd lecture is scheduled for early Sept.
by: Leo Hwa Liang, 08-Aug-2014 03:44 PM.
IVLE: BN3101: Uploading of Introduction to BN3101 slides
Dear students, I have just uploaded the introduction slides for the Monday BN3101 orientation. This is the first of a series of online lectures throughout this semester.Regards,
by: Aneel Kumar Maheshwari, 07-Aug-2014 02:15 PM.
BN3101 Groups
Dear Students,Welcome to BN3101 students.A Gentle reminder for BN3101 orientation lecture on Monday at 10am (EA-02-11) and also you can see the project supervisors and groups on IVLE.See you all soon.
Dr. Leo

Industrial flexible manipulators

For teaching purpose, this page is listing related flexible manipulators, which are cited from related websites.
An incomplete comparison table FYI ListOfFlexibleManipulators.pdf

OC Robotics

designs and manufactures snake-arm robots, which are specifically designed to perform remote handling operations in confined and hazardous spaces. OC Robotics has delivered robots for industries spanning – amongst others – nuclear, aerospace, medical and security. It has also provided consultancy and analysis services for these sectors.

Features: Snake-arm robots have a long, slender and flexible design, fitting effortlessly through small openings and around obstacles. Snake-arm robots do not need support from the environment, which means that they can navigate through an open space, avoiding obstacles, carrying tools and conducting work.

SAMSUNG Electronics

Amazing mechatronics from the SAMSUNG Electronics people for a NOTES structure. Significantly more advanced that the KAIST robot presented before.  (A 2013 video of the system.)

Titan Medical‘s SPORT single port robot

Intuitive surgical da Vinci Sp Single Port Robotic Surgical System

Intuitive Surgical receives FDA clearance, unveils da Vinci Sp system.

Full story: While the FDA has already given clearance to the system, Intuitive Surgical plans to hold off on releasing it to market until it’s been made fully compatible with the latest da Vinci Xi robot.

Olympus Endoeye flex

Note: our NUH cardiac surgeons preferred this system for their epi-cardiac procedures!
The Olympus EndoEye Flex 5 offers HD resolution in a 5 mm diameter scope. The device uses digital-chip technology to place the camera on the tip of the scope, delivering high-quality, bright images and enabling doctors to see fine details during surgical procedures. Additionally, the scope allows for 100-degree angulation in all directions.

corindus: CorPath

The CorPath Vascular Robotic System enables the precise, robotic-assisted control of coronary guidewires and balloon/stent devices.

Festo: Bionic Handling Assistant BHA

Excellent pneumatic actuated flexibility!

transenterix: SurgiBot Spider Surgical system

SPL with bi-manual control capability.

endocontrol: JAIMY

JAiMYTM, the first motorized articulating laparoscopic instrument with iD-intelligent Dexterity, is designed to enable surgeons to overcome the unique challenges presented by single incision and conventional laparoscopic surgery.

Flexible endoscope

Richard Wolf Urology flexible endoscope “cobra” & laser for stone management: the first dual channel uretero renoscope

Tendon-driven Flexible Manipulator

Project goals

This project aims to develop a flexible manipulator for transnasal/transoral surgery. Compared with existing surgical manipulators, the developed one should have better performance in workspace and dexterity, thus better facilitate the surgical operation.


A constrained tendon-driven serpentine manipulator (CTSM) is designed as shown in Figure 1. It includes an underactuated tendon-driven flexible section, a constraint and a set of tendons. The tendon-driven flexible section is similar to our previous wire-driven robot arm design. It comprises of several identical vertebras, and an elastic tube. Two successive vertebras form a joint and the joint rotation follows the elastic tube bending. Four tendons pass through all the vertebras. For each tendon, the two ends are attached to the distal vertebra and the motor respectively. These tendons are grouped to two pairs and are orthogonally arranged as shown in Figure. 1 (b). One tendon pair controls the bending about X axis and the other tendon pair controls the bending about Y axis. The manipulator bending is planar. The bending angle and bending direction are controlled by the motion of the four tendons. The constraint can be an elastic tube or rigid tube. The constraint translates along the tendon-driven flexible section. Vertebras in the range of the constraint are confined and vertebras out of the range of the constraint are free of rotation. Thus, the last constrained vertebra serves the base of the bending section.

Figure 1 3D design of the CTSM: (a) the assembled and explosion view of the CTSM; (b) the tendon configuration; (c) the cross section view of the joint.

The bending motion of the manipulator is shown in Figure 2: when the insertion of the constraint is 0, the CTSM bends by the tendons as a traditional TSM. By pushing the constraint forward the backbone is segmented to two parts: the proximal constrained section and the distal free bending section. Compared to the distal free bending section, the proximal constrained section is stiffer and the joints’ rotations are smaller. By pushing and pulling the constraint, the lengths of the two sections are controlled.

Fig. 2 Bending motion illustration: (a) the bending section is not constrained; (b) part of the bending section is constrained; (c) the whole bending section is constrained.


A prototype is built as shown in Figure 3. In the prototype, the flexible backbone has 27 vertebras. The vertebras are fabricated by 3D printing, and the material used is plastic. Each joint can rotate up to 7.25°.The total length of the flexible backbone is 104mm, and the diameter is 7.5mm. A silicon rubber tube serves the elastic tube. The outer diameter is 3 mm and inner diameter is 2 mm. Four steel wires with nylon coating are used to control the backbone bending. The diameter of the steel is 0.3 mm. The wires are arranged orthogonally, with opponent wires make a pair. Each wire pair is connected to a drum wheel. The rotation of the drum wheel is controlled by a servo motor. The diameter of the drum wheel is 50 mm. The wires are guided by a Teflon tube, whose outer diameter is 0.9 mm and inner diameter is 0.5 mm. The replaceable constraint is hold by a chuck, which is mounted on the linear actuator. The range of the linear actuator is 100 mm.


By changing the stiffness ratio between the flexible bending section and the overall stiffness λ, the workspace of the CTSM is as shown in Figure 4. In the simulation the length of the CTSM is 100 mm, and the number of vertebrae is 25.

Fig. 4 workspace comparison: (a) traditional TSM; (b) CTSM with elastic constraint; (c) CTSM with elastic constraint; (d) CTSM with rigid constraint.

When the CTSM with a rigid constraint is attached to a mobile base, the workspace and dexterity distribution are shown in Figure 5. For the tendon-driven serpentine manipulator (TSM), the dexterity is indexed as the kinematic flexibility. For a traditional TSM, the kinematic flexibility is 1 in most places; the maximum is 2. For the designed CTSM, the kinematic flexibility is enhances all over the workspace and the maximum is 15.


Figure 5 Comparison of the dexterity distribution over the workspace: (a) traditional TSM; (b) CTSM with λ=0.

People involved

Staff: Zheng Li
Visiting Students: Gui Fu, Zhengchu Tan, Jan Feiling
PIs: Hongliang Ren and Haoyong Yu

Experiment Videos

– Phantom tests

– CTSM Experiments in ex-vivo hearts and phantoms (2014/11/22)


1. Zheng Li, Haoyong Yu and Hongliang Ren, “A Novel Constrained Tendon-driven Serpentine Manipulator (CTSM)”, ICRA 2015 (under review)
2. Zheng Li, Haoyong Yu and Hongliang Ren, “A Novel Underactuated Wire-driven Flexible Robotic Arm with Controllable Bending Section Length”, ICRA 2014 Workshop on Advances in Flexible Robots for Surgical Interventions, Hong Kong, May 31-June 7, 2014
3. Zheng Li, Ruxu Du, Haoyong Yu and Hongliang Ren, “Statics Modeling of an Underactuated Wire-driven Flexible Robotic Arm”,IEEE BioRob 2014, Sao Pauo, Brazil, Aug12-15, 2014

Presentation at BIOROB2014

Presentation at ICRA 2014

Poster at ICRA 2014


Fig. 3 CTSM prototype.


Tip Tracking and Shape Sensing for Flexible Surgical Robots

Project Goals

As a typical minimally invasive surgery, transoral surgery brings to patients significant benefits such as decreased intra-operative blood loss, less post-operative complication morbidity, shorter hospitalization length and recovery period. Flexible surgical robot (such as tendon/wire/cable-driven robot and concentric tube robot) is an efficient device for transoral inspection and diagnosis. It can work well in complicated and confined environments. One drawback of this method is that the real time tip position and shape information cannot be well estimated, especially when there is payload on the end effector. To address these challenges, we focus on a novel tip tracking and shape sensing method for the flexible surgical robot.


The proposed method is based on the positional and directional information of limited specific joints of the robot, which are estimated with an electromagnetic tracking system. Electromagnetic sensors have been mounted in the tip of the robot to provide the tip position and direction information. Based on the section number of the robot, some other sensors will be mounted in the specific position of the robot to realize the shape sensing. The shape sensing method is based on multi quadratic Bézier curves.

Fig.1 Electromagnetic tracking method.

The electromagnetic tracking method is shown in Fig.1. A uniaxial sensing coil is used as the target and sensing the magnetic field that generated by the six transmitting coils. These six coils are stimulated sequentially. The position and orientation information of the sensing coil can then be estimated based on the sensing signals.

Fig.2 Shape sensing method.

Fig.2 shows the shape sensing method for multi-section flexible by using multi quadratic Bézier curves. For a N sections robot, ⌈N/2⌉ electromagnetic sensors will be mounted in the tail of the (N-2k)th section, where 0≤k<n/2. Therefore, by utilizing the positional and directional information of the sensors, each section can be reconstructed based on a quadratic Bezier curve. Compared to the image based method, this method is easy to setup; compared to the FBG based method, curvature information is not used and fewer sensors are needed in the proposed method.

Results and Remarks


Fig.3 Two Uniaxial electromagnetic sensing coils are mounted in both ends of the device.

We have applied the method on a 10-joints wire-driven flexible robot. As shown in Fig.3, two uniaxial electromagnetic sensors (Aurora Shielded and Isolated 5DOF Sensor, 0.9* 12mm) have been mounted on both ends of the robot. Fig.4 shows the average errors of the experimental results of each S shape curve reconstruction in the experiments. The whole average error is 1.4mm.
We have also applied the method on a two-section concentric tube. As shown in Fig.5, a uniaxial sensor has been mounted in the tip of the robot. The tracking results can be seen in the video.

Fig.4 Experimental results for the wire-driven flexible robot.


Fig.5 Tip tracking and shape sensing for concentric tube robot. The result can be seen in the video below.

The primary contributions of our work are summarized as follows:
1)A shape sensing method based on Bézier curve fitting and electromagnetic tracking is proposed. This method needs only the positional and directional information of some specific position of the curved robot.
2)Only limited sensors are needed, and thus very few modifications are required on the robot.
3)Compared with other methods, the proposed method is easy to set up and has a good accuracy.

People Involved

Staff: Shuang Song, Zheng Li
Investigators: Hongliang Ren, Haoyong Yu



[1] Shuang Song, Wan Qiao, Baopu Li, Chao Hu, Hongliang Ren and Max Meng. “An Efficient Magnetic Tracking Method Using Uniaxial Sensing Coil”. Magnetics, IEEE Transactions on, 2014. 50(1), Article#: 4003707
[2] Shuang Song, Hongliang Ren and Haoyong Yu. “An Improved Magnetic Tracking Method using Rotating Uniaxial Coil with Sparse Points and Closed Form Analytic Solution”. IEEE Sensors Journal, 14(10): 3585-3592, 2014
[3] Shuang Song, Baopu Li, Wan Qiao, Chao Hu, Hongliang Ren, Haoyong Yu, Qi Zhang, Max Q.-H. Meng and Guoqing Xu. “6-D Magnetic Localization and Orientation Method for an Annular Magnet Based on a Closed-Form Analytical Model”. IEEE Transactions on Magnetics. 2014, 50(9), Article#: 5000411