Nonlinear Observers for asynchronous measurement or irregular dating systems : application to underwater robotics dedicated to multisensor-based control

Aïda Feddaoui (Oct. 2016) (co-supervision with LIS)

Funding : Ministry

Supervision : Eric BUSVELLE (LIS), Vincent HUGEL and Nicolas BOIZOT (LIS)

The research work proposed consists of developing tools for the dynamical estimation of a physical nonlinear system’s state. These tools — typically observers — intend to improve the existing techniques of multi-sensor-based control, in particular in the field of underwater robotics.
The developments will concern two types of continuous‐discrete systems that do not meet the usual assumptions allowing the use of observers whose convergence is ensured : 1) asynchronous measurement systems, and 2) irregular dating systems.

  1. The multiple outputs of a system are usually issued from several sensors. Generally and this is an assumption that is very far away from the physical world, these sensors are assumed to be synchronous, i.e. they all provide measurements at the same time. We propose to study the observability and to develop a specific observer as well as suited theoretical concepts in order to relax the assumption of sensor synchronicity.
  2. The family of irregular dating systems is composed of continuous‐discrete systems whose measurement acquisition times are not exactly known. This case occurs quite often when the information that is delivered by sensors is transmitted over a network whose protocols do not always guaranty an actual real-time data transmission.
    This kind of issues, barely studied in terms of observers, happens quite often in mobile robotics. In particular, underwater robots rely on optical and acoustic measurements for their navigation, including GPS localizing at sea surface, all measurements being neither synchronous nor always precisely dated.