The performance benefits of an aerodynamically unstable aircraft are obtained at the expense of the necessity of an automatic control system. For reliability requirements controllers without gain scheduling are looked...
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The performance benefits of an aerodynamically unstable aircraft are obtained at the expense of the necessity of an automatic control system. For reliability requirements controllers without gain scheduling are looked for. To achieve this a complex ”robust control” design problem has to be solved. Fuzzy-controllers are claimed to have robustness properties. On the other hand the fuzzy-control methodology can be seen as a systematic way to specify controllers with nonlinear gain surfaces. To properly tune such controllers, computer-aided techniques can be applied provided appropriate models are available such as in more classical design approaches. A fuzzy-controller is developed, which keeps an aerodynamically unstable aircraft stationary for a sufficient long range of time and providing good flying qualities over the entire flight envelope. The results are compared with a completely linear controller design, done earlier.
The robot trajectory optimization features of the ANDECS environment are described. Robot trajectory optimization problems are formulated as multi-objectives parameter optimization problems in search for a good compro...
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The robot trajectory optimization features of the ANDECS environment are described. Robot trajectory optimization problems are formulated as multi-objectives parameter optimization problems in search for a good compromise among conflicting criteria, such as “minimal” time and “minimal” power consumption. For that the robot dynamics is analyzed by time-simulation of a robot model with variable structure, which is generated by the object-oriented modeling language Dymola.
In many robotics applications, e.g. telerobotics under long time delay, building a geometric world model from multisensory data is a crucial requirement. Using a sensor-in-hand configuration to generate a model refere...
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In many robotics applications, e.g. telerobotics under long time delay, building a geometric world model from multisensory data is a crucial requirement. Using a sensor-in-hand configuration to generate a model referenced to the robot base, imposes specific problems. Moving the sensor frame on an arbitrary path over and around an unknown object generates a completely unordered 'data cloud'. A surface reconstruction algorithm, which is based on Kohonen's self-organizing feature maps is used to process this data cloud and to generate a useful surface description. This surface can be used for object recognition and pose estimation using algorithms which were developed in the field of range image understanding.
For a low speed Maglev system of the single stage suspension type a control design study is described where a ’classical’ dynamic compensator control structure is compared with a ’modern’ LQG control structure. To...
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For a low speed Maglev system of the single stage suspension type a control design study is described where a ’classical’ dynamic compensator control structure is compared with a ’modern’ LQG control structure. To properly tune the free parameters in the respective controller synthesis procedures the ANDECS-MATLAB design environment is used. The multi-objective design approach of ANDECS allows to simultaneously satisfy the suspension requirements corresponding to both random and deterministic inputs.
Artificial potential fields have enjoyed growing popularity for path planning and collision avoidance both of robot manipulators and mobile robots. Although many artificial potential fields have been proposed. Few wor...
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Artificial potential fields have enjoyed growing popularity for path planning and collision avoidance both of robot manipulators and mobile robots. Although many artificial potential fields have been proposed. Few works discuss suitable control for tracking the gradient of an artificial potential field. This deficit is surprising since good tracking control is vital for successful implementation of the artificial potential field method. This paper extends previous results of a sliding mode control strategy for fully actuated holonomic robots to gradient tracking of non-holonomic mobile robots.
This paper continues demonstration of the benefits of parallel multibody simulation. In Part I implicit integration schemes combined with a modified inverse dynamic formulation were proposed for parallel multibody sim...
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This paper continues demonstration of the benefits of parallel multibody simulation. In Part I implicit integration schemes combined with a modified inverse dynamic formulation were proposed for parallel multibody simulation. In Part II the modified inverse dynamics algorithm and computation of the integrator's Jacobian are split up into independent work packages for parallelization on medium-and coarse-grain levels, respectively. The farming concept, which organizes the flow of work and result packages through a network of processors, is presented. Transputers are used to build a distributed memory multiprocessor system, where both the medium- and coarse-grain approaches are implemented, resulting in the PARSIM-package for parallel multibody dynamics. The simulation of an off-road vehicle and a multibody model for a cable demonstrate the considerable savings in simulation times achieved by the new software package.
The benefits of parallel multibody simulation are demonstrated in this paper. In Part I an extensive analysis of the options available in parallel multibody system simulation is given. As a result of this analysis, im...
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The benefits of parallel multibody simulation are demonstrated in this paper. In Part I an extensive analysis of the options available in parallel multibody system simulation is given. As a result of this analysis, implicit integration schemes are proposed for simulation and a modified inverse dynamic formulation is presented, which generates the equations of motion directly, in an implicit differential-algebraic form. In Part II medium-and coarse-grain levels will be exploited for the parallelization of the modified inverse dynamic formulation and the integrator's Jacobian, respectively. Both approaches are implemented on a Transputer network, resulting in the PARSIM-package for parallel multibody simulation. Computational efficiences of the package are demonstrated.
Four-wheel car steering is modeled by a single-track model with nonlinear tire characteristics. A generic control law for robust decoupling of lateral and yaw motion by yaw-rate feedback to front-wheel steering is der...
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Four-wheel car steering is modeled by a single-track model with nonlinear tire characteristics. A generic control law for robust decoupling of lateral and yaw motion by yaw-rate feedback to front-wheel steering is derived. Ideal steering dynamics are achieved by velocity-scheduled lateral acceleration feedback to front-wheel steering. For robust yaw stabilization a velocity-scheduled yaw-rate feedback to rear-wheel steering is given, by which the linearized system gets velocity-independent yaw eigenvalues.
This article reports on two main contributions: the introduction of a parallel distributed architecture for robot vision, and robust robot vision techniques and their computationally efficient parallel implementation ...
Highway automation is a promising approach to cope with increasing road traffic and congestions. An important control subtask of an intelligent vehicle/highway system is automatic steering for lateral vehicle control....
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Highway automation is a promising approach to cope with increasing road traffic and congestions. An important control subtask of an intelligent vehicle/highway system is automatic steering for lateral vehicle control. Due to system uncertainties and the wide range of operating conditions, state-of-the-art robust control techniques are required. This paper introduces two automatic steering controllers for cars driving under highway conditions. The control design is based on sliding mode control and robust state observation. It is shown that good tracking of a reference path, delineated either continuously or discretely, can be achieved with a minimum effort in sensing and without preview of the road curvature.
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