Browsing by Issue Date, starting with "1988-10"
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- Filosofias da Qualidade (Quality Gurus) - desenvolvimento de uma cultura da qualidade na empresaPublication . Fonseca, LuísSão analisadas as principias metodologias e abordagens de Deming, Juran, Crosby, Ishikawa e Taguchi, visando identificar quais as mais adequadas para diversos tipos de cultura organizacional.
- Robot manipulator dynamics - Towards better computational algorithmsPublication . Tenreiro Machado, J. A.; Carvalho, J. L. Martins de; Matos, J. A. Silva; Costa, António M. C.A new robot manipulator inverse dynamics computational algorithm is announced. The novel feature resides in the computations which are a blend of ordinary and Boolean algebra. As such, this method may also be interpreted as a dedicated compiler that optimizes the on-line computing time at expenses of the off-line stage. Nervertheless, the high off-line requirements are alleviated, through the derivation of some general rules that stem from the structure of the robot manipulator equations. In a practical implementation, a copmuter program based on a Quine-McCluskey truth table simplification method was used and experimented on a 2R robot manipulator. The results show a considerable computational improvement on a conventional sequential machine. Furthermore. they clearly point out new comptutational parallel architectures, without scheduling problems, and where performance improvement is porportional to the number of processors. Finally, it is observed that the proposed algorithm is not restricted to robot inverse dynamic computations, but also applicable to kinematic and control computations.
- A statistical approach to the analysis and design of robot manipulatorsPublication . Tenreiro Machado, J. A.; Carvalho, J. L. Martins deA new approach the the analysis and design of robot manipulators is announced. The novel feature resides on a non standard approach to the modelling problem. Usually, system descriptions are based on a set of differential equations which, due to their nature lead to very precise results and strategies but, can be very complex to tackle. This motivates the need of models based on other mathematical comcepts having distinct characteristics. The proposed statistical scheme is a step in that direction which gives clear guidelines towards the robot kinematic and dynamic optimization. Furthermore, the inherent use of histograms allows not only fast calculation procedures, but above all, the use of experimental data; consequently, complex dynamic modelling exercises can be avoided.