Two-time scale visual servoing of eye-in-hand flexible manipulators

Visual servoing of eye-in-hand flexible manipulators is addressed in this paper. Dynamic effects of both the rigid and the flexible motion of the manipulator are fully taken into account in a control solution where the two-time scale nature of the problem is exploited. The visual information is used in the "slow" subsystem for a task-space-oriented control law, where computationally expensive operations, such as inverse and time derivative of the Jacobian, are avoided. A constructive proof of stability of this control scheme, based on Lyapunov theory, is also presented. The effectiveness of the proposed controller is shown by means of a numerical simulation concerning a trajectory tracking problem. Some experimental results finally demonstrate the precision enhancement achieved by the proposed algorithm on a single-link flexible manipulator.     

The purification of fatty acid methyl esters by high pressure liquid chromatography

Procedures are described for the rapid purification of gram quantities of methyl oleate, methyl linoleate, methyl α- and γ-linolenates and methyl ricinoleate from appropriate natural oils by high pressure liquid chromatography (HPLC).     

Revising the Robust-Control Design for Rigid Robot Manipulators

Robust controllers for robot manipulators ensure stability of the closed-loop system, even if only partial knowledge of the dynamic model of the manipulator is available. Existing derivations of robust-control laws, while guaranteeing the stability result, present an undesired dependence of the robust-control term on the gains of the controller for the nominal system. This dependence forces larger robust-control terms when the nominal control gains are large. Based on a structured representation of the model uncertainty, this paper proposes a derivation of the robust-control law, where these limitations are removed. Experimental results on the COMAU SMART 3S industrial robot in a 3-degree-of-freedom (DOF) configuration confirm the advantages of the proposed controller.      

Acceptability of robotic manipulators in shared working environments through human-like redundancy resolution

Next generation robotic manipulators are expected to resemble a human-like behavior at kinematic level, in order to reach the same level of dexterity of humans in operations like assembly of small pieces. These manipulators are also expected to share the same working environments with humans without artificial barriers.