[robotics-worldwide] Phd Position - High-speed vision-based control - Deadline 14/07/08

Andrew Comport Andrew.Comport at lasmea.univ-bpclermont.fr
Tue Jul 8 01:22:26 PDT 2008

PhD position:

Dynamic control of parallel kinematic manipulators using high-speed vision

1 Context and motivation

This position is open within the Robotics and Autonomous Complex Systems 
group (ROSACE), interested in the control of robotic systems. This group 
is part of the "Laboratoire des Sciences et Matériaux pour 
l’Electronique et d’Automatique" (LASMEA) in Clermont-Ferrand, France. 
The scholarship is funded through the French research agency's (ANR) 
”Young Researcher” project VIRAGO dealing with the vision-based control 
(or visual servoing) of parallel kinematic manipulators.

Parallel kinematic manipulators, as opposed to serial kinematic 
manipulators, are composed of a mobile platform linked to its base by 
several kinematic chains. They thus allow for greater speed 
manipulation, higher loads and higher repeatability than serial 
kinematic manipulators. However, their control is made harder since one 
has to take into account the closure of the various kinematic chains. A 
way to by-pass much of the associated control difficulties is to perform 
eye-to-hand based visual servoing since it alleviates the problem of 
solving the theoretically hard forward kinematic problem. Nevertheless, 
classic visual servoing is essentially a kinematic control scheme that 
assumes sufficiently low speeds to neglect the dynamic effects due to 
inertia or Coriolis forces. This is not realistic in the case of 
parallel kinematic manipulators designed for high-speed.

Therefore, we have been developing a formal framework for high-speed 
vision-based computed torque control, where vision copes with the high 
control frequencies and the control laws with the rigid body dynamics. 
The approach has been validated on the Orthoglide prototype in Nantes and
accelerations of 1G were reached. The PhD candidate will have to extend 
this framework to take into account flexibilities that can not be avoided 
at really high speed. In particular, the experimental validation will 
take place on the new Adept Quattro robot which reaches 20G accelerations.

2 Prerequisites

• Good mathematical background
• Good mechanical engineering background (multi-body dynamics, robot
• Basic knowledge in computer vision
• Programing skills
• Preferably fluent French but fluent English can be accepted

3 Important dates

Application deadline: July 14th, 2008.
Decision: July 21st, 2008
First working day: No later than September 1st, 2008.

4 Contact persons

Nicolas Andreff, Name.Surname at lasmea.univ-bpclermont.fr
Phone: +(33) 4 73 40 52 56

Andrew Comport, Name.Surname at lasmea.univ-bpclermont.fr
Phone: +(33) 4 73 40 72 33

Dr. Andrew Comport
CNRS Researcher
Robotics and Autonomous Complex Systems
Campus des Cézeaux
24 Avenue des Landais
Tel : (+33)
Fax : (+33)

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