Performing fine manipulations with multifingered robot hands makes high demands on the control algorithms and the speed of the controlcomputer. Mainly nonlinear friction problems and plant uncertainties require inten...
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Performing fine manipulations with multifingered robot hands makes high demands on the control algorithms and the speed of the controlcomputer. Mainly nonlinear friction problems and plant uncertainties require intensive fine-tuning of a controller. This paper gives insight into the frictional behaviour of geared finger links. The behaviour has been approximated by a friction model. Considering the estimated system parameters two kinds of controllers are developed: a simple PD controller with switchable I-part and a PD-controller with a fuzzy friction compensation working in parallel. The results of both controllers are presented and compared in this paper.
One of the main problems of present-day microsystem technology (MST) is the assembly of a whole microsystem from different micro-components. This paper presents an automated micromanipulation desktop station the main ...
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One of the main problems of present-day microsystem technology (MST) is the assembly of a whole microsystem from different micro-components. This paper presents an automated micromanipulation desktop station the main feature of which are piezoelectrically driven microrobots placed on a highly precise x-y table of a microscope. The microrobots can perform high-precise manipulations (with an accuracy of up to 10 nm) and the transport of very small objects (at a speed of several mm/sec). To control the desktop station automatically, a sensor system is provided for fine and for gross positioning of the robots, respectively. Apart from assembly tasks this automated station can be used, for examples, for handling biological cells or testing silicon chips.
This paper describes the development of a system for simultaneous planning and execution of surgical operations in the cranio-maxillo facial area. Simultaneous planning and execution is the process of taking an implic...
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While distributed control architectures have many advantages over centralized ones, such as their inherent modularity and fault tolerance, a major problem of such architectures is to ensure the goal-oriented behaviour...
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While distributed control architectures have many advantages over centralized ones, such as their inherent modularity and fault tolerance, a major problem of such architectures is to ensure the goal-oriented behaviour of the controlled system. This paper presents a framework within which the coordination skills required for goal-orientedness are learned from user demonstrations. The framework is based on a state-space model of the single agents building the system and a corresponding model of the coordination mechanism. Our mobile robot PRIAMOS provides an application example.
A strategy for the fusion of information from a stereo image pair for model-based object recognition is discussed. Our scheme combines a new method for feature grouping with a region-based stereo matching and a hypoth...
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A strategy for the fusion of information from a stereo image pair for model-based object recognition is discussed. Our scheme combines a new method for feature grouping with a region-based stereo matching and a hypothesize-and-verify paradigm. The grouping method developed is based on a graph theoretical algorithm. It exploits prior knowledge to find the groups of image features which are likely to come from a sought model(s). The Bayesian classification is used to deal with the resulting hypotheses. A mechanism for a dynamic threshold modification is incorporated into the system to enable the grouping at different resolutions. Unlike classical techniques for object recognition from stereo, our strategy does not depend on a data driven computation of a depth map. We argue that a propulsive reconstruction of 3D information can be more efficient and robust.
The emerging field of service robots demands new systems with increased flexibility. The flexibility of a robot system can be increased in many different ways. Mobile manipulation—the coordinated use of manipulation ...
Strong international competition forces enterprises to reduce organizational overhead and cost. Today's industrial practices allow, in general, only the selection of whole planning and controlsystems for CIM (e.g...
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Strong international competition forces enterprises to reduce organizational overhead and cost. Today's industrial practices allow, in general, only the selection of whole planning and controlsystems for CIM (e.g., CAD systems, PP&C systems,...). These systems can be adapted only in a limited range to the user requirements. With the introduction of executable enterprise models to the industrial environment, it is expected that it will be possible to design tailored CIM systems built of standardized software modules which will lead to higher complexity of the planning process for software systems. Thus, today's planning and selection approaches will face more and more problems. In order to master the increasing complexity of the planning of software systems for enterprises, new planning methods and tools are required. An integrated approach to software system planning and selection based on CIMOSA enterprise models was developed. The underlying idea of the approach is the conversion of the planning problem into an equivalent constraint satisfaction problem. The conversion process can be accomplished fully automatically.
The use of manipulator systems with many degrees of freedoms is essential to expand the field of potential applications. This paper presents a distributed approach for executing task-level programs for cooperating man...
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The use of manipulator systems with many degrees of freedoms is essential to expand the field of potential applications. This paper presents a distributed approach for executing task-level programs for cooperating manipulators or one-arm systems with many degrees of freedom. At task level, only the movement of the objects to be manipulated is specified. The according manipulator motions are then calculated by assigning local intelligence to each joint. The local intelligence enables the joint agents to calculate in parallel their appropriate movements to make the end effector reach the desired position. During execution, each joint evaluates sensor data to compensate for execution errors, to react on unexpected obstacles and to provide the manipulator coordination. Therefore, a distributed fuzzy rule base has been developed. As this local evaluation may lead to non-optimal overall behavior of the manipulator, the joint agents communicate to provide global suboptimality.
A mobile robot that navigates in an unknown or changing environment needs to maintain a dynamic model of its environment in order to update existing knowledge about the world. This paper addresses the problem of how t...
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A mobile robot that navigates in an unknown or changing environment needs to maintain a dynamic model of its environment in order to update existing knowledge about the world. This paper addresses the problem of how to update a local model of the perceivable environment of a mobile robot and how to produce a description of newly perceived obstacles. A new hybrid concept is presented which combines the advantages of parameter- and grid-based modelling techniques. By introducing local grids that only cover areas where new obstacles are expected, the complexity of the map building process is significantly reduced. Local grids can be used in dynamic environment which was not possible with earlier grid-modelling approaches. The information, grids are constructed from, is provided by ultrasonic range sensors and an active stereo-vision system, Fusing information of both sensor systems is advantageous, especially due to their complementary error characteristics concerning range and angular resolution.
Intelligent control architecture of autonomous robot systems must be modular, scaleable, extendible, and adaptable to the available capacity of computercontrolsystems. For the support of these properties, the concep...
Intelligent control architecture of autonomous robot systems must be modular, scaleable, extendible, and adaptable to the available capacity of computercontrolsystems. For the support of these properties, the concept of adaptive control structure, ACS, is presented in this paper. Experiments with small autonomous assembly robot show the successful use of ACS.
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