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Browsing by Issue Date, starting with "1999-11-01"

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  • Kinematic robustness of manipulating systems
    Publication . Galhano, Alexandra; Tenreiro Machado, J. A.
    Present day mechanical manipulators have poor performances when compared with the human arm. In fact, joint-drivem manipulators are not efficient dues to the high actuator requirements imposed by the transients of the operational tasks. Muscle-actuated arms are superior because the anatomic levers adapt the manipulating exigencies to the driving linear actuators. The kinematic analysis of these systems highlights its main properties and constitutes a step towards the design of new mechanical biological-like robotic structures adopting linear actuators replacing the standard rotational joint-driving motor systems.
    1999-11-01Conference object Open access Show more
  • A chaos perspective in the trajectory control of redundant manipulators
    Publication . Duarte, Fernando B. M.; Tenreiro Machado, J. A.
    Several kinematic control algorithms for redundant manipulators adopt generalized inverse matrices. In this line of thought, the generalized inverse control scheme is tested through experiments that reveal the difficulties that often arise. Motivated by these problems this paper studies kinematics and dyanmics of trajectory planning scheme. The experiement confirm the non-linear and chaotic performance of the algorithm and gives a deeper insight towards the future development of superior trajectory control systems.
    1999-11-01Conference object Open access Show more
  • Advanced control of robot in tecnological operation
    Publication . Tar, József K.; Rudas, Imre J.; Tenreiro Machado, J. A.; Horváth, László
    A novel adaptive robot control tackling the problem of the approximately known robot dynamics and the unknown external dynamic interactions is presented in this paper. By applying uniform structures derived from the Euler-Lagrange equations in the most general and formal level it differs from and overcomes the limitations of classical feedfoward neural network-based approaches as far as the a priori unknown number of the necessary nodes and the scaling ranges of free parameters are concerned. Using a relatively simple structure of reduced number of parameters real time tuning can be carried out in the control. From the point of view of the possible local optimums resulting in improper control the structure here used seems to have the possible least complexity and coupling for a given degree of freedom robot. Several task- independent ancillary procedures also support the control. The method is illustrated via simulation in the case of a 3 active and one passive DOF SCARA arm used for polishing the surface of a bell-shaped work-piece.
    1999-11-01Conference object Open access Show more