In this paper the control architecture of the PRIAMOS mobile robot system is presented. It consists of four layers which integrate reactive and reflexive components in such a way that the robot can combine fast reacti...
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In this paper the control architecture of the PRIAMOS mobile robot system is presented. It consists of four layers which integrate reactive and reflexive components in such a way that the robot can combine fast reaction to unexpected obstacles with predictive behaviour to known components in the environment. A solution for the problem of how to combine control layers which process information on different levels of abstraction and of increasing complexity is discussed. The reflexive part of the control architecture and the modification concerning the motion controller of the mobile robot which was necessary to apply the idea of reflexive navigation is described in more detail. The architecture presented allows motion tasks to be executed in partially unknown or changing environment in an efficient manner. Especially, the time-critical reflexive level is computationally less expensive than in previous approaches.
Hybrid position/force control for robotic manipulators is considered. The control is carried out in task coordinates. For the force control the non-linear variable structure controller is presented and investigated. T...
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Hybrid position/force control for robotic manipulators is considered. The control is carried out in task coordinates. For the force control the non-linear variable structure controller is presented and investigated. The controller maintains the system to reach and remain at the switching hypersurfaces, consisting of internal coordinates of the force controller. The stability of the system and the existing of the sliding mode are analyzed by means of the second Lyapunov method. The developed non-linear force controller was implemented for the hybrid position/force control of a PUMA 200 manipulator. The experimental setup and obtained results are described.
In this paper the framework of an intelligent control system of a multi-finger robot hand is described, that is especially tailored for sensor-based object handling and assembly. The research has concerned with the Ka...
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In this paper the framework of an intelligent control system of a multi-finger robot hand is described, that is especially tailored for sensor-based object handling and assembly. The research has concerned with the Karlsruhe dextrous hand, a modular three-finger hand with 9 degrees of freedom, independent finger modules and integrated sensors. The total system structure consists of three embedded subsystems, with a planning and supervisory system on the top, which has a blackboard-like architecture to exchange information with a distributed real-timecontrol system that provides force/position control strategies for dextrous grasping and manipulating of arbitrary objects. A programming and simulation system supports the object/task-based description of all robot and gripper actions required to perform a specific operation.< >
This paper deals with the two fundamental problems that occur when objects are manipulated with multi-finger robot hands: the determination of the joint motions to perform a manipulation according to a given object tr...
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This paper deals with the two fundamental problems that occur when objects are manipulated with multi-finger robot hands: the determination of the joint motions to perform a manipulation according to a given object trajectory, and the optimization of the joint torques needed to ensure a stable and secure grip. The consideration of the effect of rolling and slipping of the fingertips at the contact points on the object surface leads to a set of linear differential equations for the joint angles and to a partly nonlinear optimization problem for the joint torques solved by the Hooke-Jeeves algorithm. The removal of redundant information reduces the computational effort to about 40% of the operations required for the standard procedure. Especially, the resulting object motions are demonstrated at an example: the rotation of an ellipsoid object with the fingers of the Karlsruhe dextrous hand.< >
The paper presents the design of a fuzzy controller to emulate spline curves for generating smooth motion trajectories. Spline models and a fuzzy control model are compared. Based on this comparison, a fuzzy control m...
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The paper presents the design of a fuzzy controller to emulate spline curves for generating smooth motion trajectories. Spline models and a fuzzy control model are compared. Based on this comparison, a fuzzy control model is devised to make the robot continuously pass through the planned subgoals guiding the robot motion. By analyzing primitive movements along subgoals, the rule base can be developed. System structures are proposed for applying this fuzzy controller in the hierarchical motion control of robot systems. Its applications in robot arms and mobile robots are also presented.< >
Path generation execution and motion control for an omnidirectional mobile robot (vehicle) are considered. real-time path generation is based on the polynomial spline-interpolation with prediction of velocities of a s...
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Path generation execution and motion control for an omnidirectional mobile robot (vehicle) are considered. real-time path generation is based on the polynomial spline-interpolation with prediction of velocities of a spline-function. The mobile vehicle control is performed with the use of its kinematic model and digital PID-controllers of the wheels. The theoretical approach is illustrated by the obtained experimental results.< >
In this paper, an approach is presented for designing a robot controller to integrate path planning and motion execution. Instead of following an exactly planned geometric path, which cannot be easily modified to deal...
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In this paper, an approach is presented for designing a robot controller to integrate path planning and motion execution. Instead of following an exactly planned geometric path, which cannot be easily modified to deal with uncertainties, a robot realizes its motion under the guidance of a sequence of grossly selected crucial points called subgoals. A fuzzy model is used for on-line controlling the robot to pass through the subgoals smoothly. With the help of heuristics for optimal motion control, the rule base can be developed. Such a concept provides a control method in realtime as well as a possibility of integrating sensor data for the subgoal-guided motion.< >
In the area of telerobotics, where remote systems are to be controlled, it is helpful to plan subsequent operations based on as much relevant data as possible. The simulation of the remote system, executed in parallel...
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In the area of telerobotics, where remote systems are to be controlled, it is helpful to plan subsequent operations based on as much relevant data as possible. The simulation of the remote system, executed in parallel, can provide additional information, otherwise difficult or impossible to retrieve from sensor feedback. In this paper, the integrated DiSCUS environment (Distributed Simulation and control in a Unix System) is presented, which is used for the simulation and the control of a small assembly cell. All (physical and logical) components are represented as stand-alone programs, as tasks. These tasks are distributed over a workstation network, so that "true" parallelism can be achieved.< >
Different powerful extensions and improvements of the control architecture of an autonomous robot are presented. They are used to increase the reliability of robot assembly and to reach a sufficient behavior. The deci...
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Different powerful extensions and improvements of the control architecture of an autonomous robot are presented. They are used to increase the reliability of robot assembly and to reach a sufficient behavior. The decision to use autonomous assembly robots in an industrial manufacturing setting depends mainly on the reliability of such a system and the extension of its manipulation capabilities. The Karlsruhe Autonomous Mobile Robot (KAMRO) is a robot system that is able to take on, and to execute, assembly tasks autonomously. Although the robot was able to work without human intervention within a limited scope, the reliability of the system was unfortunately not adequate for large-scale applications. This paper describes how the reliability has been improved and which experiments were performed to evaluate the concept.< >
Increasing the flexibility of robot systems has been one of the main objectives of robotics research in recent years, There are various approaches to achieve this: increasing fault-tolerance on different levels, the d...
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Increasing the flexibility of robot systems has been one of the main objectives of robotics research in recent years, There are various approaches to achieve this: increasing fault-tolerance on different levels, the development of sophisticated sensors, grippers and manipulators, and the use of learning techniques. But the field of operation of such smart systems is still limited to a rather small area. Mobile manipulation is another facet of increasing the flexibility of a robot system. By exploiting the mobility of a platform, the dexterous workspace of manipulators can be considerably increased. One main research topic on mobile manipulation is the decomposition of the motion of the tool-center-point into manipulator motion and platform motion. In this paper a new online approach to this decomposition is presented which allows the consideration of complex obstacles and multiple manipulators mounted on the platform. Simulation studies verify the suitability of the approach. Some of the realized algorithms have been applied to a real mobile two-arm system.< >
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