In this research, a dynamic model is first established based on screw theory and the principle of virtual work for a bilaterally symmetrical hybrid robot. By combining a novel composite error (NCE) with second-order nonsingular fast terminal sliding mode (SONFTSM) control method, a NCE-based SONFTSM dynamic control method is further presented to guarantee better trajectory tracking performance and synchronization performance simultaneously. The asymptotic convergence of proposed errors and the stability of the proposed control method have been proved theoretically. Finally, the simulation and experiment are implemented to validate the effectiveness of the proposed control method.

Electric-powered wheelchairs improve the mobility of people with physical disabilities, but the problem to deal with certain architectural barriers has not been resolved satisfactorily. In order to solve this problem, a stair-climbing mobility system (SCMS) was developed. This paper presents a practical dynamic control system that allows the SCMS to exhibit a successful climbing process when faced with typical architectural barriers such as curbs, ramps, or staircases. The implemented control system depicts high simplicity, computational efficiency, and the possibility of an easy implementation in a microprocessor-/microcontroller-based system. Finally, experiments are included to support theoretical results.

L’évolution des teneurs en CO et CO2 dans les gaz à la sortie d’unconvertisseur industriel présente un comportement reproductible, qui reflète ladécarburation du bain métallique. Malgré les limitations présentes dans les équipements demesure installés au convertisseur de Siderar – analyse des gaz seulement et pas de mesurede débit des gaz produits – il a été possible de mettre en place une méthode permettantd’estimer la teneur en carbone de l’acier à la fin du soufflage d’oxygène. Il a étédéterminé que le temps écoulé entre le moment où le maximum de la courbe de teneur enCO2 apparaît, quelques minutes avant la fin du soufflage, et le moment del’arrêt du soufflage est la variable qui permet d’estimer au mieux la teneur en carbone del’acier. La méthode développée permet d’améliorer de façon significative la précisiond’obtention de la teneur en carbone d’arrêt par rapport aux pratiques conventionnelles.Les analyses réalisées ont montré que parmi les variables évaluées, celle-ci est la plusrobuste car elle est peu sensible à l’influence des paramètres qui affectent les entréesd’air dans le système et qui ont une influence directe sur les analyses du gaz. Afin demettre en œuvre cette méthode en tant qu’outil de contrôle de process en temps réel, il aété développé un système expert qui analyse point par point l’évolution de l’analyse desgaz du convertisseur, détecte le maximum de CO2 et envoie un signal au PLC pourremonter la lance de soufflage d’oxygène au moment voulu pour obtenir la teneur en carbonevisée.

In this paper, a joint space dynamic control scheme with an adaptive identifier is proposed for free-flying space robots. The control in Cartesian space poses a measurement problem which is critical from a point of view of implementation. In order to overcome this problem, a joint space control is developed. An inverse kinematics algorithm is proposed so as to control free-flying space robots in joint space. Since the inverse kinematic solutions for space robots depend on the dynamic parameters as well as the kinematic.parameters, the accurate estimation of all the unknown parameters is essential to make joint space control possible. Therefore, an off-line adaptive parameter identification is performed for free-flying space robots. Simulation results are given to show the validity and the effectiveness of the presented adaptive identification and dynamic control scheme.

This paper reports on the control structure of the pneumatic biped Lucy. The robot is actuated with pleated pneumatic artificial muscles, which have interesting characteristics that can be exploited for legged locomotion. They have a high power to weight ratio, an adaptable compliance and they can absorb impact effects.

The discussion of the control architecture focuses on the joint trajectory generator and the joint trajectory tracking controller. The trajectory generator calculates trajectories represented by polynomials based on objective locomotion parameters, which are average forward speed, step length, step height and intermediate foot lift. The joint trajectory tracking controller is divided in three parts: a computed torque module, a delta-p unit and a bang-bang pressure controller. The control design is formulated for the single support and double support phase, where specifically the trajectory generator and the computed torque differs for these two phases.

The first results of the incorporation of this control architecture in the real biped Lucy are given. Several essential graphs, such as pressure courses, are discussed and the effectiveness of the proposed algorithm is shown by the small deviations between desired and actual attained objective locomotion parameters.

In this paper a new concept, named the Extended Operational Space (EXOS), has been proposed for the effective analysis and the real-time control of the robot manipulators with kinematic redundancy. The EXOS consists of the operational space (OS) and the optimal null space (NS): the operational space is used to describe manipulator end-effector motion; whereas the optimal null space, described by the minimum number of NS vectors, is used to express the self motion.

Based upon the EXOS formulation, the kinematics, statics, and dynamics of redundant manipulators have been analyzed, and control laws based on the dynamics have been proposed. The inclusion of only the minimum number of NS vectors has changed the resulting dynamic equations into a very compact form, yet comprehensive enough to describe: not only the dynamic behavior or the end effector, but also that of the self motion; and at the same time the interaction of these two motions. The comprehensiveness is highlighted by the demonstration of the dynamic couplings between OS dynamics and NS dynamics, which are quite elusive in other approaches.

Using the proposed dynamic controls, one can optimize a performance measure while tracking a desired end-effector trajectory with a better computational efficiency than the conventional methods. The effectiveness of the proposed method has been demonstrated by simulations and experiments.

The paper discusses some practical problems of contact dynamics. Modelling the dynamics of contact tasks is carried out in a completely general way. Two dynamic systems, active robot system and passive environment system are brought into contact and the relevant dynamics are analyzed. The effects are: rigid-body contact force, elastodynamics in contact zone, friction in contact points, etc. Simultaneous stabilization of contact force and position is obtained using New Dynamic Position/Force Control. The general model is then applied to some more concrete problems and the simulation results are presented.

The goal of this paper is to present a new method to control pushing operations with several fingers. We take into account some dynamical aspects that have not yet been investigated in pushing studies such as the object's center of mass acceleration correction and optimal force distribution. To do this, we use a general method for multi-chain mechanisms based on a dynamical control with finger coordination. We first detail the problems encountered in this type of manipulation and the way to take these points into account with specific constraints definition for the support contact. According to the parameters of the model such as optimization criterion and object characteristics, we present simulation results of object pushing with two fingers for a rotational and translational motion.