Electrical and Electronic Engineering - Research Publications

Permanent URI for this collection

Search Results

Now showing 1 - 4 of 4
  • Item
    Thumbnail Image
    On non-local stability properties of extremum seeking control
    Tan, Y ; Nešić, D ; Mareels, IMY (Elsevier BV, 2005-01-01)
  • Item
    Thumbnail Image
    Control of large-scale irrigation networks
    Cantoni, M ; Weyer, E ; Li, Y ; Ooi, SK ; Mareels, I ; Ryan, M (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2007-01-01)
  • Item
    Thumbnail Image
    Adaptive repetitive learning control of robotic manipulators without the requirement for initial repositioning
    Sun, M ; Ge, SS ; Mareels, IMY (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2006-06-01)
  • Item
    Thumbnail Image
    Stability and motor adaptation in human arm movements
    Burdet, E ; Tee, KP ; Mareels, I ; Milner, TE ; Chew, CM ; Franklin, DW ; Osu, R ; Kawato, M (SPRINGER, 2006-01-01)
    In control, stability captures the reproducibility of motions and the robustness to environmental and internal perturbations. This paper examines how stability can be evaluated in human movements, and possible mechanisms by which humans ensure stability. First, a measure of stability is introduced, which is simple to apply to human movements and corresponds to Lyapunov exponents. Its application to real data shows that it is able to distinguish effectively between stable and unstable dynamics. A computational model is then used to investigate stability in human arm movements, which takes into account motor output variability and computes the force to perform a task according to an inverse dynamics model. Simulation results suggest that even a large time delay does not affect movement stability as long as the reflex feedback is small relative to muscle elasticity. Simulations are also used to demonstrate that existing learning schemes, using a monotonic antisymmetric update law, cannot compensate for unstable dynamics. An impedance compensation algorithm is introduced to learn unstable dynamics, which produces similar adaptation responses to those found in experiments.