Todays’ applications of manipulators in industry are restricted to environments which are known in advance and specially adapted to robots, as these manipulators are not flexible enough to move reliably in unknown or...
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Todays’ applications of manipulators in industry are restricted to environments which are known in advance and specially adapted to robots, as these manipulators are not flexible enough to move reliably in unknown or complex environments. In this paper, we present a multi-agent based reactive planning and control system for redundant manipulators. This approach enables the reactive motion of manipulators in an unknown environment. In the system described in this paper, an agent is responsible for calculating and controlling the motion of one joint, therefore it is called “joint agent”. A joint agent is responsible for evaluating the sensors on the according link, for calculating motions of the joint which minimize the distance of the endeffector to a cartesian goal and which avoid sensed obstacles. These local algorithms possess only small complexity compared to the algorithms needed for global optimal motion planning and can be calculated very fast. Thus reactive motions are possible. The agents are coordinated by communication. Additionally to the coordination by communication, a superior level is responsible for optimizing the agents’ actions by evaluating complexer criteria. Besides that, the local sensor data is integrated into a global model of the environment on this level. This paper concentrates on the local reactive level. Several local criteria in order to generate the reactive movements are presented. Our testbed, a redundant manipulator covered with tactile sensors, is presented in detail.
controlling multifingered robot hands makes high demands on the control algorithms and the speed of the controlcomputer. The nonlinear friction, the impact problem and other plant uncertainties require a special kind...
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controlling multifingered robot hands makes high demands on the control algorithms and the speed of the controlcomputer. The nonlinear friction, the impact problem and other plant uncertainties require a special kind of control and tuning of the controller. Some simple linear and nonlinear controllers for the Karlsruhe Dexterous Hand are presented and the results and advantages of the controllers are shown. Also, a new adaptive fuzzy controller is presented to overcome the time consuming process of fine-tuning the membership functions. Finally, a short glance at the hardware platform is taken in order to show the control system architecture.
In contrast to a hierarchical and centralized structure, distributed or decentralized control architectures reveal their main advantages when it is necessary to enhance the system, to integrate components, and to main...
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In contrast to a hierarchical and centralized structure, distributed or decentralized control architectures reveal their main advantages when it is necessary to enhance the system, to integrate components, and to maintain the system. The main disadvantage of not centralized architectures is having to make sure that the system will fulfill an overall or global goal. To investigate these problems, a distributed control architecture for intelligent systems was developed at the University of Karlsruhe. In this paper, the methods for dead-lock-free coordination and cooperation are explained.
Within the last years the programming by demonstration (PbD) programming methodology gained more and more attention in robotics. However, a high quality way of human-robot interaction is crucial for a successful appli...
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Within the last years the programming by demonstration (PbD) programming methodology gained more and more attention in robotics. However, a high quality way of human-robot interaction is crucial for a successful application of the PbD methodology in robotics. Hypotheses derived from the programming system, and control knowledge included in a generated robot program has to be checked back with and to be verified by the user in order to avoid potentially harmful errors that lead to faulty code. This paper describes a method for user-robot interaction that is based on 3D-icons and supports and facilitates the programming process in a robot programming by demonstration system significantly.
The need for simulation in medical environments increases with the complexity and risks of operations. Exact geometric planning is one of the main problems a surgeon has to deal with. The goal of the authors' rese...
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The need for simulation in medical environments increases with the complexity and risks of operations. Exact geometric planning is one of the main problems a surgeon has to deal with. The goal of the authors' research is the development of a graphical simulation of the human mastication system. Therefore, they are developing an integrated model of the jaw by parameterizing the bones (maxilla and mandible) and modeling the motion capabilities as well as the mastication muscles. The main focus of the paper is the introduction of a kinematic model of the temporomandibular joint and modeling of the mastication muscles. The kinematic model describes the geometrical and analytical movement of the jaw by specially defined axes. By modifying the axes or the geometrical model of the mandible, a surgeon can get a first impression of the post-operative result of, for example, a repositioning. Through integration of the muscles and muscle forces, one can even obtain a dynamic simulation of the whole mastication system.
Micromanipulation has become an issue of primary importance in industry and biomedicine, the manual capabilities being restricted to certain tolerances. For example manipulation of biological cells or an assembly of a...
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Micromanipulation has become an issue of primary importance in industry and biomedicine, the manual capabilities being restricted to certain tolerances. For example manipulation of biological cells or an assembly of a whole microsystem composed of different microcomponcnts have to be carried out by piezo electrically-driven miciorobots. For this reason, an automated microrobot-based micromanipulation station is developed by an interdisciplinary group at the University of Karlsruhe. The process of assembly takes place in the field of view of a light optical microscope. The principal sensors of the S3rstem are CCD cameras. One of them, coupled with the microscope, is the local sensor that allows the automation of the manipulation process under the microscope. A second one, the global sensor, supervises the entire system. In this work we present the first step of a method for the detection of faults occurring during the manipulation process. This first stage consists of detecting and processing a position deviation of the microrobot.
The authors present a microassembly system model based on geometric reasoning. Its components, which include an X-Y positioning table with a glass plate fixed on top of it, operating microrobots on the plate, and a CC...
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The authors present a microassembly system model based on geometric reasoning. Its components, which include an X-Y positioning table with a glass plate fixed on top of it, operating microrobots on the plate, and a CCD-camera, are discussed in detail. Feasibility criteria for the generation of possible assembly sequences and optimisation criteria for selecting the best assembly plan, which reflect the specific features of microassembly, are suggested. For both planning steps, algorithms for an automatic procedure have been developed and implemented. An important advantage of te suggested bottom-up search procedure is that the assembly plan is determined at each step of the algorithm, so that the searching of all feasible sequences and the selection of the best one are integrated into one automated planning procedure. This allows one to replan the assembly process during plan execution, starting from the current process state and without exploring the space of all possible assembly plans. For a multirobot system, a method for decomposition of an assembly plan and its implementation is suggested.
The design of a microassembly desktop station is a major challenge for microsystem technology. This paper presents several piezoelectric micromanipulation robots, which have been developed to be used in a microassembl...
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The design of a microassembly desktop station is a major challenge for microsystem technology. This paper presents several piezoelectric micromanipulation robots, which have been developed to be used in a microassembly station. These robots are of different design and use different actuation principles so that each robot serves for a specific task. They are capable of travelling over long distances and of manipulating in the range of a few nanometers. Several robots of this kind can be accommodated in a microassembly station and can cooperate and perform microassembly tasks as a team. They can also be used for other operations such as online testing of microelectronic chips or manipulating biological cells.
作者：
J. SeyfriedS. FatikowUniversity of Karlsruhe
Institute for Real-Time Computer Systems and Robotics (IPR) Kaiserstr. 12 (Geb. 40.28) D-76128 Karlsruhe F. R. of Germany Phone: +49-721-608-3656 Fax: +49-721-606740
In the fields of biology, microelectronics and microsystem technology many operations are today performed by hand which might also be done by micromanipulation robots. Several prototypes of such robots have already be...
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In the fields of biology, microelectronics and microsystem technology many operations are today performed by hand which might also be done by micromanipulation robots. Several prototypes of such robots have already been built and tested, but in the field of controlsystems and user interfaces of such micromanipulation systems, there is still much work to be done. Different applications demand different levels of control and planning: easyier, single tasks may be performed by teleoperation, while others require a programmed motion sequence or even task planning to accomplish a complex assembly task a with minimum of human interaction. This paper presents a micromanipluation system consisting of a microassembly robot working under a light-optical microscope, a CCD camera and an XY-stage. Then, the software infrastructure for the microrobot control system is presented and the underlying hardware system is described. It also shows a user interface based on this structures, a semi-automated teleoperation system. The user interface presented here uses the live image of the CCD camera to perform either open or closed loop control of the robot's position. All parameters of the microscope and XY-stage can be controlled with dialog windows. The software infrastructure allows also the development of task planning algorithms by providing an intermediate layer to control the robot
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