A novel concept of a smooth distance function for online collision detection and avoidance is presented. The concept is well suited for real-time obstacle avoidance path planning. Computation efficiency is achieved by...
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A novel concept of a smooth distance function for online collision detection and avoidance is presented. The concept is well suited for real-time obstacle avoidance path planning. Computation efficiency is achieved by three properties: 1) the 'collision' surfaces of obstacles need to be approximated by local grid point sets only; 2) a manipulator is approximated by a finite set of ellipsoids (or balls); and 3) its gradient exists and can be calculated efficiently due to the smoothness of the distance function. The concept exploits the recursive forward kinematic structure and is not based on a configuration space representation. Hence it is also applicable for kinematically redundant (multi-) manipulator systems.
We propose a numerically reliable state space algorithm for computing coprime factorizations of rational matrices with factors having poles in a given stability domain. The new algorithm is based on a recursive genera...
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ISBN:
(纸本)0780341872
We propose a numerically reliable state space algorithm for computing coprime factorizations of rational matrices with factors having poles in a given stability domain. The new algorithm is based on a recursive generalized Schur technique for poles dislocation by means of proportional-derivative state feedback. The proposed algorithm is generally applicable regardless the underlying descriptor state space representation is minimal or not, or is stabilizable/detectable or not.
A practical solution of controlling flexible-joint robots is to control the joint torque, i.e. a robust joint torque controller with fast enough response is required. The position control problem of the flexible-joint...
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A practical solution of controlling flexible-joint robots is to control the joint torque, i.e. a robust joint torque controller with fast enough response is required. The position control problem of the flexible-joint robot will be reduced to the control of a rigid-body robot. This paper is dedicated to design such a torque controller using traditional feedback control and sliding mode techniques. Different from the conventional applications of sliding mode, which lead to the so-called chattering effects, sliding mode techniques are used in an estimation process to enhance the robustness of a pole-placement design. Hence, no chattering will be exicted
作者：
Wolfgang SienelDLR
German Aerospace Research Center Institute for Robotics and System Dynamics Oberpfaffenhofen 82234 Wessling Germany
Stability analysis of nominal systems can be performed easily by computation and inspection of the plant's eigenvalues. This approach is quite common for nominal plants. If the plant model, however, contains bound...
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Stability analysis of nominal systems can be performed easily by computation and inspection of the plant's eigenvalues. This approach is quite common for nominal plants. If the plant model, however, contains bounded uncertain parameters, then sets of eigenvalues, i.e. regions in the complex plane must be calculated. The most important stability information is contained in the right hand boundary of such regions, which will be referred to as stability profile. For a small number of uncertain parameters the stability profile may be approximately calculated by parameter grid approaches. For a larger number of uncertain parameters it is essential to exploit specific uncertainty structures in the characteristic equation. An iterative method for computation of the stability profile by way of value set construction is presented for a class of uncertain systems and applied to the dlr plate experiment with 60 uncertain parameters.
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.
Key items in the development of a new smart robot generation are explained by hand of dlr's recent activities in robotics research. These items are the design of multisensory gripper systems, ultra-light-weight li...
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Key items in the development of a new smart robot generation are explained by hand of dlr's recent activities in robotics research. These items are the design of multisensory gripper systems, ultra-light-weight links and joint drive systems with integrated joint torque control, learning and self-improvement of the dynamical behaviour, modelling the environment using sensorfusion, and new sensor-based off-line programming techniques based on teaching by showing in a (stereo)graphics environment. For each of these issues either simulated or real design results are given.
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.
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