This paper presents a suitable scheme for the fault detection and isolation of a high voltage DC electrical network in more electric aircraft. Concerning a more electric aircraft architecture comprising one variable f...
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This paper presents a suitable scheme for the fault detection and isolation of a high voltage DC electrical network in more electric aircraft. Concerning a more electric aircraft architecture comprising one variable frequency generator, one 18-pulse autotransformer, power electronic converters, high voltage DC transmission lines, electromagnetic actuators and numerous constant electrical loads e.g. lighting and PCs, the multi-model detection approach reveals more convenience and feasibility to undertake fault analysis at network level regarding the dynamic change of electrical loads. Right-sized system modelling, computer-aided trimming and linearization with Dymola are discussed. Nullspace based approach is used for synthesis of a residual generator. As demonstration, an application case where a short circuit fault occurs on the output of a buck converter in the more electric aircraft is considered. The designed residual generators are validated on the original nonlinear system with time-domain simulation.
IDEFIX is a four-wheeled 25kg rover that is jointly developed and built by the French Centre National d’Études Spatiales (CNES) and the German Aerospace Center (DLR). It will be brought to the Martian Moon Phobo...
IDEFIX is a four-wheeled 25kg rover that is jointly developed and built by the French Centre National d’Études Spatiales (CNES) and the German Aerospace Center (DLR). It will be brought to the Martian Moon Phobos by the Japan Aerospace Exploration Agency (JAXA) as part of the Martian Moons eXploration (MMX) mission in 2027. IDEFIX’s objectives are to scout the surface, demonstrate driving in milligravity and perform scientific measurements. To upright after landing on the surface, drive and align the rover to the sun, each wheel is mounted on a leg, which can be rotated full 360° in its respective shoulder joint. In previous publications, the development, flight design and qualification of the locomotion subsystem were *** the cruise phase there will be several health checks and – once landed on Phobos – the locomotion will be checked-out. To be able to analyze the health state quantitatively and parameterize the system properly, a good characterization of the system is important. The foundation of this characterization are tests and health-checks on the flight model (FM), as well as performance test results on the qualification model (QM). A selection of the post-processing and analysis of this measured data, that was done for the characterization of the Loco FM, is presented in this paper.
This paper represents one of the results of the second Herbertov Workshop in 1992 on ''Research Issues in Automotive Integrated Chassis Control systems''. It was decided to bring together engineers who...
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ISBN:
(纸本)9026513801
This paper represents one of the results of the second Herbertov Workshop in 1992 on ''Research Issues in Automotive Integrated Chassis Control systems''. It was decided to bring together engineers who are actively involved in current software developments to report on the progress in integrated system analysis and design software for controlled vehicles. Therefore, after mentioning some of the principal requirements for such software, the state-of-the-art is summarized. Promising recent research and software developments are described and the application of some of these concepts to an actively controlled vehicle with preview is discussed. Throughout the article the ideas of concurrent analysis and design strategies are emphasized.
Robots with pneumatic drives have advantageous physical properties and are lightweight and cost-effective. During operation, a pneumatic robot handles objects of different payloads, which are often not known in advanc...
Robots with pneumatic drives have advantageous physical properties and are lightweight and cost-effective. During operation, a pneumatic robot handles objects of different payloads, which are often not known in advance. Determining the mass of this load is crucial for user assistance functions, trajectory generation and model-based control to increase both productivity and ease of use. In this work, a model-based approach for estimating the mass of a payload gripped by a pneumatically driven robot is presented. This approach does not require additional force or torque sensors, but uses the joint angle and pressure sensors already installed for control purposes. From these signals, the non-measurable effective driving torque is calculated model-based, taking into account the particularities of the pneumatic drives. As a basis for the estimation, the robot equations of motion are formulated such that they are linear in the dynamic parameters of the robot. An optimization problem is set up and solved with a recursive least squares method to estimate the payload online. This is extended by a logic to activate the estimation when a payload is picked. The algorithm is validated experimentally on a pneumatic robot performing a typical pick-and-place task.
In this paper we investigate the feed-forward learning problem. The well-known ill-conditioning which is present in most feed-forward learning problems is shown to be the result of the structure of the network. 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 shuttle COLUMBIA in April 93, but it also gives...
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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 shuttle COLUMBIA in April 93, but it also gives a review of the major space robot projects envisioned by different nations for the next decade. The mecha-tronics 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.
作者：
A. VargaDLR Oberpfaffenhofen
German Aerospace Research Establishment Institute of Robotics and System Dynamics D-82234 Wessling Germany
The non-redundant parametrization of the pole assignment problem for a n-th order system with m inputs allows to express the solution of the problem in term of n(m - 1) free parameters. These parameters can be used to...
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The non-redundant parametrization of the pole assignment problem for a n-th order system with m inputs allows to express the solution of the problem in term of n(m - 1) free parameters. These parameters can be used to fulfill additional requirements on the closed-loop system as for instance minimum norm feedback gain matrix, well conditioned eigenvector set, maximum stability radius. One of reliable numerical methods for pole assignment is the so-called Schur method. An extension of this method is proposed which computes the solution of the pole assignment problem corresponding to a non-redundant parameter set. Several possibilities are further investigated to compute minimum norm feedback matrices. An improved approach to compute minimum Frobenius-norm feedback relying on a redundant parametrization is also discussed.
In this paper, we prove that, for an interval system, the maximal H ∞ norm of its sensitivity function is achieved at twelve (out of sixteen) Kharitonov vertices. We also study the envelope of the Nyquist plots gener...
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In this paper, we prove that, for an interval system, the maximal H ∞ norm of its sensitivity function is achieved at twelve (out of sixteen) Kharitonov vertices. We also study the envelope of the Nyquist plots generated by a family of stable transfer functions with multilinearly correlated uncertainties and show that the outer Nyquist envelope is generated by the Nyquist plots of the vertices of this family. We then apply this result to calculating the maximal H ∞ norm and verifying the strict positive realness condition for uncertain transfer function families.
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