Two PhD positions available at Delft University of Technology, The Netherlands

Two PhD positions in Human and Robotic Arm Movement


General project description


Both PhD project are part of an multi-academic project, called STIFF,
funded by the European Union. The goal of STIFF is to equip a highly
bio-mimetic robot hand-arm system with the agility, robustness and
versatility that are hallmarks of the human motor system by
understanding and mimicking the variable stiffness paradigms that are so
effectively employed by the human CNS. A key component of the study will
be the anatomically accurate musculoskeletal modeling of the human arm
and hand. The project will develop novel methodologies to comprehend how
the human arm can adapt its impedance, e.g. by changing the
co-contraction level or by adapting the reflex gains. The impedance of
the arm and of the hand will be investigated using powerful robot
manipulators capable of imposing force perturbations. While stiffness is
currently known on artificial laboratory tasks we will investigate
stiffness behavior during natural tasks like throwing a ball or
inserting a peg in a hole. The existing closed-loop system
identification techniques will be extended with non-linear time-variant
techniques which can identify the behavior during reaching and grasping
tasks. The grasp force modulation and hand muscle activity correlations
will be learned for use on the robotic system. Finally, optimization
techniques gleaned and validated on the detailed biophysical model will
be transferred to the variable impedance actuation of the novel
biomorphic robotic system. The central question that this project
focuses on for both the human and robotic arm is: 'how is stiffness used
to enhance performance?' and this project represents one of the first
attempts where targeted modeling studies will go the full circle by
exploiting these results for optimal control of an embodied,
high-dimensional, variable-impedance robotic system. Within the STIFF
project, two following PhD positions become available that both have
their focus on human movement control.



PhD project I: Identification of multi-joint stiffness during arm
movement

Aim of this project is to identify joint impedance during movement using
a 2DOF arm robot. Joint impedance is the result of muscle
visco-elasticity and reflexive feedback which are both controlled from
the brain. Knowledge of the temporal changes of these components reveals
the control of arm movement and therefore should be separated from the
joint impedance measurements. For this purpose, neuromuscular models
need to be developed or refined to map impedance to the underlying
neuromuscular properties.

Main deliverables of the project:

* Development and application of time varying impedance
measurements

* Improvement of the existing Delft Shoulder and Elbow Model
(DSEM) by incorporation of neural feedback controllers (muscle spindles,
tendon organs) and improvement of the existing muscle models based on
cross-bridge dynamics

* Linearization of the DSEM, including feedback pathways and
optimization algorithms for position, velocity and force feedback, using
the system matrix

* Forward simulation of reaching movements, incorporating feed
forward and feedback control



Candidate's profile

* M.Sc. in Mechanical or System and Control Engineering or a
closely related field, with outstanding results.

* Strong background in biomechanics and system identification

* Experience in (biomechanical) modeling and simulation

* Combination of academic attitude and engineering skills

* Excellent writing and presentation skills in English





PhD project II: Development of a neuromuscular model of the human hand

Aim of this project is to develop a computer model of the human wrist
and hand for analysis of human grasping. The model will be connected to
the existing Delft Shoulder and Elbow Model (DSEM) to investigate the
relationship between arm and hand/finger motions during different tasks
and loading demands.

Main deliverables of the project:

* Anatomical data (cadaver study) needed for wrist and hand
model

* Wrist and hand model implemented in SPACAR and validation with
experimental data for grasping conditions

* Identification of finger impedance and estimation of muscular
and neural feedback components

* Incorporation of dynamic muscle models and neural feedback
controllers (muscle spindles, tendon organs) for the hand and finger
joints in SPACAR.



Both PhD projects are assigned for four years (period 2009 - 2013) and
operated in a consortium of several European Universities. Hosting
institute is Delft University of Technology, Laboratory for
Neuromuscular Control (NMC Lab), part of the section Biomechanical
Engineering. Day-to-day support is provided by NMC research members,
headed by prof. dr F. C. T. van der Helm. Salary amounts Euro 2294 in
the first year to Euro 2465 in the fourth year.



Candidate's profile

* M.Sc. in Human Movement Science, Biomedical Engineering or
Mechanical Engineering or a closely related field, with outstanding
results.

* Strong background in biomechanics

* Experience in biomechanical modeling

* Combination of academic attitude and engineering skills

* Excellent writing and presentation skills in English





Contact

Please send your application including your Curriculum Vitae, list of
three persons for reference, a list of publications (if applicable), a
summary of your M.Sc. thesis and a cover letter stating your motivation
to prof. dr F.C.T. van der Helm, Biomechatronics and Biorobotics,
Biomechanical Engineering, faculty of Mechanical, Maritime and Materials
Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft,
The Netherlands



Additional information can be obtained from prof. dr F.C.T. van der Helm
(f.c.t.vanderhelm@tudelft.nl ) or
dr E. de Vlugt (e.devlugt@tudelft.nl ).