Micha Hersch

Post-doc in the Computational Biology Group of Prof. Sven Bergmann at the Department of Medical Genetics headed by Prof. Jacqui Beckmann, University of Lausanne (UNIL) and at the Swiss Institute of Bioinformatics (SIB).

email: micha.hersch at unil.ch



Ph.D

Summary

Basically, what I tried to do in my Ph.D. is to take inspiration from the way we, humans, do to move our limbs around to grasp objects and manipulate them, to control the limbs of a humanoid robot, to enable him to do the same thing.
Although, we don't usually think about it, it is quite amazing how good we are at finding our way through space, dealing with our bodies, with objects and manipulating them. Because I am very clumsy, I am maybe more aware of it than others, which probably lead me to this research topic.
My hypothesis is that our dexterity is made possible by some "representation" of the space surrounding us. Or, if you don't like the word representation, our perception of space is structured in some way, which is intrinsically linked to our motor abilities. That, which structures our representation of space, has been called the body schema. The body schema has long been the topic of debates and investigations among neurophysiologists, psychologists and phenomenologists and its definition is still disputed. In the first part of my thesis, I suggest a computational model of some aspects of the body schema suitable for a humanoid robot.
In the second part of my thesis, I suggest a reaching controller based on what we know about human control of reaching movements. Of course the human arms are very different from robotic arms, so similarity can only be present at the level of underlying principles, and this is what I tried to do. The underlying principles I tried to implement in the robot controller are multi-modal control on one hand and dynamical system control on the other hand.
In the third part of my thesis, I tried to tackle somewhat more complex behavior, building on my reaching controller. I try to give the robot the ability to perform very simple manipulation behavior.

Movies

Here are a few movies illustrating my work.

Learning the body schema

A simulation showing the learning of the body schema. Starting from scratch, the simulated robot learns its shape (light gray) and motor rotation axes (dark gray) online by looking at its hands and feet. The algorithm used is described in this paper

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avi file (3 Mb)

Learning the head and eye rotation axes

The iCub robot learns how to visually track a target by learning the rotation axes of the motor in its head. This is done by analyzing the visual flow resulting from its head and eye motions as described in my thesis.

  avi file (7 Mb)

Adaptive reaching movements

The iCub robot reaching a visually tracked target using the multi-referential dynamical system control, while learning its body schema at the same time. First the reaching in imprecise because the robot is badly calibrated. Then it becomes more precise as the robot learns its body schema.

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  avi file (10 Mb)

Adaptive reaching movements

The iCub robot reaching a visually tracked target using the multi-referential dynamical system control, while learning its body schema at the same time. The robot can adapt from reaching with one finger to reaching with another finger if the color marker indicating the reaching finger is displaced.

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  avi file (13 Mb)

The control of reaching movements

The Hoap2 robot reaching a visually observed target using the multi-referential dynamical system control described in this paper

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  avi file (10.6 Mb)

Learning to put an object into a box

The Hoap3 robot learning to put an object into a box in a way robust to initial conditions and online perturbation as described in this paper.

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  avi file (13 Mb)

Grasping a chess piece

The Hoap3 robot reproducing the chess task (grabbing a chess piece) described in this paper.

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  mpg file (14 Mb)

Bibliography

The .bib file I used for my thesis is available here and I have an electronic version of most of those papers in this big file [1GB] .