Active magnetic bearing (AMB) actuators support rotors without friction but require feedback control for stabilization and performance. We address the application of modern control techniques such as LQG/LTR, H/spl in...
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In the paper a simulation environment for evaluation of knowledge based fault diagnostic systems is presented. The contribution deals with the concept of the environment that provides an integration of qualitative and...
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In the paper a simulation environment for evaluation of knowledge based fault diagnostic systems is presented. The contribution deals with the concept of the environment that provides an integration of qualitative and quantitative models. This concept is presented on a simulated water-column processcontrolled by feedback. The simulation environment is used to evaluate the potentials of Multilevel Flow Modelling (MFM) approach to system diagnosis. The environment is realized within the real-time expert system tool G2.
A modern system theory point of view is offered for the design of sequencing controllers for discrete event manufacturing systems, whereby the controller is considered as separate from the workcell. The controller has...
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A modern system theory point of view is offered for the design of sequencing controllers for discrete event manufacturing systems, whereby the controller is considered as separate from the workcell. The controller has a rule-based structure with inner loops where no shared-resource conflict resolution is required, and extra control inputs in an outer loop to resolve conflict and remove deadlock (where needed). The controller design is based on the required task sequence and the available resources; it is described by linear (i.e. matrix) and nonlinear logical equations. The controller-workcell interaction expressed both in qualitative and quantitative terms supports a rigorous analysis of conflicts and deadlock. Three methods for conflict and deadlock resolution related to current work are efficiently incorporated in the general design framework. The design algorithm naturally accommodates a performance analysis in terms of the (R,max,+) representation as a consequence of the link established between that approach and the rule-based controller equations. Compatibility with other analysis/design techniques is briefly addressed.
The paper gives an overview of some results and lessons learned from the application of object-oriented (OO) techniques to real-time systems development. These results have been obtained within the scope of a research...
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The paper deals with geometrical model correction of 3D rigid objects situated in a robotic environment. This problem is extremely important both for intelligent robots and for industrial robotic workcells. The propos...
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Previously presented methods for online collision avoidance for robots in a two-dimensional space are extended to the third dimension. Even if global planning and programming are done in multi-robot workcells, in real...
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Previously presented methods for online collision avoidance for robots in a two-dimensional space are extended to the third dimension. Even if global planning and programming are done in multi-robot workcells, in real-world applications it is important to supervise the actual movements and to influence them if necessary, due to sensor-driven changes of the trajectories, incomplete information on the environment, and possible failures in mechanical or electrical devices. Therefore, precautions have to be taken for online collision detection and avoidance. Besides the considerations of dynamics for online collision avoidance in 3-D space, attention is given to the online computing of the algorithms and their execution on parallel hardware.
In this paper different methods are compared for tuning a robust PID controller for a heating process in an extruder. These tuning methods are internal model control, Clarke method, and Cohen & Coon method. Robust...
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In this paper different methods are compared for tuning a robust PID controller for a heating process in an extruder. These tuning methods are internal model control, Clarke method, and Cohen & Coon method. Robustness is needed because the process is nonlinear. By using process model uncertainty the robust stability theorem is employed to assure that the feedback loop with the nonlinear process and the linear PID controller will be stable at all operating points. The model uncertainty is approximated with the help of a nonlinear physical model, which is based on heat balance equations. The controller parameters are selected to satisfy the requirement of the robust stability under model uncertainties.< >
The paper solves a real-time extension of the supervisory control problem for a class of real-time discrete event systems with hybrid components. The considered plant is parallel composition of subsystems each with gu...
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The paper solves a real-time extension of the supervisory control problem for a class of real-time discrete event systems with hybrid components. The considered plant is parallel composition of subsystems each with guaranteed infimal delays between two subsequent output discrete events, with true parallelism, and with delayed response to input events. The delayed response depends on current state of plant. It is modelled using one integrator for each controllable event. An event is actually disabled if the value of integrator is equal or higher than "hybrid controllability" of the event. The minimally restrictive solution is presented.< >
Hybrid controllability describes delayed response of plant to control actions dependent on current i/o trajectory. The minimally restrictive controller for a plant with hybrid controllability solving a time extension ...
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Hybrid controllability describes delayed response of plant to control actions dependent on current i/o trajectory. The minimally restrictive controller for a plant with hybrid controllability solving a time extension of supervisory control problem is sensitive with respect to inaccuracies of hybrid plant parameters. The paper presents a controller which is more restrictive but works properly in presence of small deviations of hybrid parameters.< >
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