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- On statistical analysis of biological armsPublication . Galhano, Alexandra; Carvalho, J. L. Martins de; Tenreiro Machado, J. A.The statistical analysis of robot manipulators reveals the limitations of joint-actuated machines. Steming from the results, in this paper we apply the statistical concepts on the study of biological arms. The superior performances of muscle-actuated arms over standard joint-actuated manipulators are demonstrated.
- On the statistical modelling of robot manipulatorsPublication . Galhano, Alexandra; Carvalho, J. L. Martins de; Tenreiro Machado, J. A.A novel approach to the modelling of robot manipulators is presented. Usually, system descriptions are based on a set of differential equations which, due to their nature, lead to very precise results and strategies but, in general, require laborious computations. This motivates the need of alternative methods based on other mathematical concepts. The proposed statistical model gives clear guidelines towards the optimization of the robot performances.
- Computer system evaluation in robot controlPublication . Tenreiro Machado, J. A.; Carvalho, J. L. Martins de; Galhano, AlexandraThe high computational burden posed by mordern control algorithms preclude its industrial application using present day microcomputers. In this paper we evaluate the computational load of different logical and arihmetic operations and the capabilities of several computing systems (software & hardware). This study reveals that real-time limitations can be alleviated through the adoption of general techniques achieve not only a more efficient management of the computational resources but also provide a deeper insight on developments towards future real-time control architectures.
- Statistical analysis of muscle-actuated manipulatorsPublication . Galhano, Alexandra; Tenreiro Machado, J. A.; Carvalho, J. L. Martins deJoint-actuated robots have poor performances due to the high 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 actuators, The statistical analysis of these systems highlights its main properties and constitutes a step towards the design of new mechanical biological-like robotic structures.
- On the evaluation of computer systems for robot controlPublication . Tenreiro Machado, J. A.; Carvalho, J. L. Martins de; Galhano, AlexandraThe high computational burden posed by modern control algorithms precludes its industrial application using present day microcomputers. In this paper we evaluate the calculation load of different logical and arithmetic operations and the capabilities of several computer systems. Thisanalysis reveals that some limitations can be alleviated through the adoptation of techniques associated with data representation. Such techniques achieve not only a more efficient management of the computational resources but also provide a deeper insight on developments towards future control architectures.
- Towards the real-time control of robotic systemsPublication . Tenreiro Machado, J. A.; Carvalho, J. L. Martins de; Galhano, AlexandraIn the last decades robot control has been an area of active research and development. Mechanical manipulators have a complex dynamics which makes difficult the design efficient controllers. Linear PID algorithms are still used in industrial robotics however, they are inappropriate for high performances. The limited efficiency of these systems motivated the development of controllers based on different concepts Dubwsky and DesForges (1), Luh e tal. (2), Freund (3). Nevertheless, the high computational load posed by many of the modern algorithms precludes its industrial application using present day microcomputers. In fact, the use of powerful monoprocessor computers is expensive while, on the other hand, multi-microprocessor architectures Luh and Lin (4), Binder and Herzog (5), Watanabe et al. (6) are still in a research stage. This situation can be overcome through the development of control strategies more adapted to the microcomputer. In this line of thought, this article compares the computational capabilities of several computers and introduces techniques capable of rendering more efficient practical implementations. It is organized as follows. In section two we evaluate the computational load posed by different operations to several computer systems. Based on the results, in section three, we present general techniques amenable to robot control implementation. Finally, in section four conclusions are drawn.
- The statistical study of biomechanical armsPublication . Galhano, Alexandra; Carvalho, J. L. Martins de; Tenreiro Machado, J. A.In a companion paper a statistical method for the analysis and design of robot manipulators was presented. The new formalism revealed the limitations of standard joint-actuated mechanical manipulators. Steming from those results, in this paper we apply the new modelling concepts on the study of biological arms. The superior performances of muscle-actuated arms over standard joint-actuated manipulators are clearly demosntrated. These results are utmost importance as they give a clear basis to the design of new mechanical robotic structures, with performances close to the biological systems.
- Towards the statistical modelling of robotic manipulatorsPublication . Galhano, Alexandra; Carvalho, J. L. Martins de; Tenreiro Machado, J. A.A novel approach to the modelling of robot manipulators is presented. Usually, system descriptions are based on a set of differential equations which, due to their nature, lead to very precise results and strategies. However, they need laborious computations and, therefore, methods based on alternative mathematical concepts are required. The proposed statistical model overcomes thes problems and gives clear guidelines towards the optimization of the robot performances.
- On statistical analysis of mechanical manipulatorsPublication . Galhano, Alexandra; Carvalho, J. L. Martins de; Tenreiro Machado, J. A.A novel approach to the modelling of manipulators is presented. Usually, system descriptions are based on differential equations which lead to very precise results but need laborious computations. The statistical modelling overcomes these problems and gives clear guidelines towards performance optimization.
- On the analysis of muscle-actuated manipulatorsPublication . Galhano, Alexandra; Tenreiro Machado, J. A.; Carvalho, J. L. Martins deIn previous studies a statistical method for the analysis and design of robot manipulators was developed. The new formalism revealed the limitations od standard joint-actuated mechanical manipulators. Steming from those results, in this paper we apply the new modelling concepts on the study of biological arms. The superior performances of muscle-actuated arms over standard joint-actuated manipulators are clearly demosntrated. Therefore, the resultes are a step towards the design of a new mechanical robotic structures, with performances close to the biological systems.