In the aim of improving safety and efficiency of robotic manipulators, links with reduced bulkiness and weight can be integrated to the robot. As a result, the manipulator becomes more flexible and might encounter vibration issues that have to be well controlled. Such flexible manipulators are said to be underactuated since they potentially have an infinite number of degrees of freedom (dof) an...

This paper considers a number of related inverse filtering problems for hidden Markov models (HMMs). In particular, given a sequence of state posteriors and the system dynamics; i) estimate the corresponding sequence of observations, ii) estimate the observation likelihoods, and iii) jointly estimate the observation likelihoods and the observation sequence. We show how to avoid a computationall...

While adaptive control has been used in numerous applications to achieve system performance without excessive reliance on system models, the necessity of high-gain learning rates for achieving fast adaptation can be a serious limitation of adaptive controllers. Specifically, in safety-critical systems involving large system uncertainties and abrupt changes in system dynamics, fast adaptation is...

Theoretical formalisms very often use non-canonical equations of motion. For example, the equations for Eulerian variables, that describe ideal continuous media, are in general non-canonical [1]. Non-canonical phase space flows can be derived from Hamiltonian dynamics by means of non-canonical transformations of phase space coordinates (i.e. transformations with Jacobian not equal to one) while...

An unknown linear plant will track an input command signal if the plant is driven by a controller whose transfer function approximates the inverse of the plant transfer function. An adaptive inverse identification process can be used to obtain a stable controller, even if the plant is nonminimum phase. A model-reference version of this idea allows system dynamics to closely approximate desired ...

In this paper, we extend stable inversion to nonlinear time-varying systems and study computational issues—the technique is applicable to minimum-phase as well as nonminimum-phase systems. The inversion technique is new, even in the linear time-varying case, and relies on partitioning (the dichotomic split of) the linearized system dynamics into time-varying, stable, and unstable, submanifolds....

Using molecular dynamics we investigate the thermodynamics, dynamics, and structure of 250 diatomic molecules interacting by a core-softened potential. This system exhibits thermodynamic, dynamic, and structural anomalies: a maximum in density-temperature plane at constant pressure and maximum and minimum points in the diffusivity and translational order parameter against density at constant te...