For the collection of Popov plots of interval trans fer function family, a large portion of its outer bo undary comes from the sixteen Kharitonov transfer functions
For the collection of Popov plots of interval trans fer function family, a large portion of its outer bo undary comes from the sixteen Kharitonov transfer functions
A perturbation estimator using the theory of variable-structure systems is designed to enhance the robustness of a pole-placement controller design in the control of joint torque. In its ideal form, the pole-placement...
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ISBN:
(纸本)0780327756
A perturbation estimator using the theory of variable-structure systems is designed to enhance the robustness of a pole-placement controller design in the control of joint torque. In its ideal form, the pole-placement design using feedback-linearization technique achieves desired performance in nonlinear time-varying systems. However, its performance deteriorates rapidly with the presence of disturbance and parametric uncertainties, referred to as perturbation. The estimate generated by the proposed perturbation estimator is incorporated as an additional input to rectify the uncertainties in the nominal control model of the pole-placement design. The proposed scheme requires neither the measurement of the time derivative of state vector nor the precise knowledge of system parameters, but rather the bounds on system perturbation. Chatter and the adverse effects of conservative bounds on system perturbation, often encountered in conventional sliding-mode control (SMC), are alleviated for the controlled plant by this scheme.
This paper introduces a sliding mode control strategy for tracking the gradient of an artificial potential field, The control methodology is applicable to fully actuated holonomic robotic systems with n-degrees of fre...
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This paper introduces a sliding mode control strategy for tracking the gradient of an artificial potential field, The control methodology is applicable to fully actuated holonomic robotic systems with n-degrees of freedom, The controller yields exact tracking of the gradient lines and is invariant with respect to parametric uncertainty and disturbances in systemdynamics, A detailed case study for mobile robots introduces the equilibrium point placement method for designing harmonic planar potential fields for circular obstacle security zones. Diffeomorph mappings can be utilized for more complex obstacle security zones, The gradient of the harmonic potential field is shown to always lead away from the obstacle security zone and to continuously approach the goal point.
Outliers in a given training data set can cause substantial deterioration of the approximation realized by a neural network architecture. Robustization refers to the process of enhancing a learning method to deal with...
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Outliers in a given training data set can cause substantial deterioration of the approximation realized by a neural network architecture. Robustization refers to the process of enhancing a learning method to deal with data containing outliers. The robustization of a learning method for training RBF networks for function approximation is presented leading to a novel efficient robust learning method for this architecture class. Its experimental evaluation confirms the expectations created from its theoretical foundations.
The paper tries to outline the state of the art in space robotics. It discusses the technologies used in ROTEX, the first remotely controlled space robot which flew with the shuttle Columbia in April 1993, but it also...
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The paper tries to outline the state of the art in space robotics. It discusses the technologies used in ROTEX, the first remotely controlled space robot which flew with the shuttle Columbia in April 1993, but it also gives a review of the major space robot projects envisioned by different nations for the next decade. The mechatronics and dynamics aspects of space robots including free-flying systems are briefly discussed. Broader attention is given to the telerobotic and teleoperational control loop structures, including predictive delay-compensating graphics simulation. The paper finally tries to emphasize that by task-level programming (involving 'learning by showing' on a high level) future space robots will be powerful tools for scientists and ground operators which are not robot specialists. The tele-sensor programming concept of ROTEX was a first step in this direction. We plead for flying a variety of space robot systems in the near future in order to enhance experience with and confidence in these technologies as quickly as possible.
Computer-aided control engineering (CACE) environments, in order to be reusable in a broad spectrum of applications, have to be based on an open software framework that provides seven classes of services: database ser...
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Computer-aided control engineering (CACE) environments, in order to be reusable in a broad spectrum of applications, have to be based on an open software framework that provides seven classes of services: database services; model-definition services; algorithmic services; tool-control services; task-control services; user-interaction services; and process-communication services. This is detailed herein with the available CACE framework for the application system ANDECS.< >
Nonlinear vehicle systemdynamics plays an important role in the development and the assessment of active suspension control systems. The current way of designing active suspension control systems mostly uses simplifi...
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Nonlinear vehicle systemdynamics plays an important role in the development and the assessment of active suspension control systems. The current way of designing active suspension control systems mostly uses simplified models, in order to to apply analytical synthesis methods or to achieve low complexity of the controller when using such methods. However, advanced vehicle design require methodologies, that can deal with more complex vehicle models, as a step towards integrated design. Multi-objective control design is such a methodology, that is open to cope with any controller structure and arbitrary kind of models. In this case study the usefulness of this methodology is investigated by designing an actively controlled vehicle suspension with and without preview for the IAVSD benchmark model ILTIS. The full nonlinear model is used for design. The ’nonlinear’ results are compared to the results of a ’linear’ design, based on linearized vehicle models.
A method is addressed for real-time dynamics trajectory optimization of kinematically redundant manipulators. The considered task of trajectory planning is to teach interactively position and orientation of the tool-c...
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A method is addressed for real-time dynamics trajectory optimization of kinematically redundant manipulators. The considered task of trajectory planning is to teach interactively position and orientation of the tool-center point frame, which is fixed in the manipulator hand. Thereby the manipulator has to autonomously preserve explicitly formulated kinematic constraints such as moving obstacle avoidance, singularity avoidance, and box-constraints on joint positions as well as dynamic constraints like box-constraints on joint velocities, accelerations and motor torques. The key idea is to transform the resulting overall motion planning problem into a time series of point-to-point trajectory planning problems, which, in turn, may be formulated as parameter optimization problems, that can be efficiently solved in real-time by the numerical method of sequential quadratic programming. Since the approach does not require an inverse kinematics formulation it is feasible for manipulators with redundant kinematics.
作者:
W. KortümDLR
German Aerospace Research Establishment Institute for Robotics and System Dynamics Oberpfaffenhofen 82234 Wessling Germany
The computational analysis of advanced mechatronic vehicles requires complex simulation models as provided by multibody system codes. Moreover, the design of such systems demands multi-objective parameter optimization...
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The computational analysis of advanced mechatronic vehicles requires complex simulation models as provided by multibody system codes. Moreover, the design of such systems demands multi-objective parameter optimization tools. This paper describes the simulation and design environment based on the multibody system code SIM PACK. As a case study the Bombardier ILTIS vehicle is “equipped” with active control loops with and without preview sensors. The multi-objective parameter optimization study using nonlinear and linear analysis methods demonstrates the feasibility of such a complex optimization strategy. Moreover, it indicates the potentials of active supensions with preview sensors. It, last not least, reveals possible misleadings of an optimization based on reduced linear design models.
Integrated systems Engineering is essential in design-concept validation. In particular, computer-aided procedures for systemdynamics integration beyond mere functional integration are necessary in order to neither u...
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Integrated systems Engineering is essential in design-concept validation. In particular, computer-aided procedures for systemdynamics integration beyond mere functional integration are necessary in order to neither underestimate nor to overestimate design-safety margins. At hand of the open system-dynamics integration environment ANDECS (ANalysis & DEsign of Controlled systems), we deal with concepts and realized features of a framework for computational experimenting in system-dynamics design and evaluation. This paper is the lead paper to four companion papers which together form a case study on applied multidisciplinary dynamics design experimenting.
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