Today's growing scientific interest in extraterrestrial bodies increases the necessity of extended mobility on these bodies. Thus, planetary exploration systems are facing new challenges in terms of mission planni...
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ISBN:
(纸本)9788494424403
Today's growing scientific interest in extraterrestrial bodies increases the necessity of extended mobility on these bodies. Thus, planetary exploration systems are facing new challenges in terms of mission planning, obstacle and soil traversability. In order to fit the tight schedules of space missions and to cover a large variety of environmental conditions, experimental test setups are complemented by numerical simulation models used as virtual prototypes. In this context we present an integrated simulation environment which allows for using different available contact models, ranging from simple but real-time capable approximations based on rigid-body modeling techniques up to very accurate solutions based on Discrete Element Method (DEM). For this work, a one-point Bekker based approach and the so-called Soil Contact Model (SCM), which is a multipoint extension of the Bekker-Wong method taking soil deformation into account, are used. These two contact models are applied for homogeneous models with only one type of contact model for all wheels as well as for a heterogeneous multi-tiered model with different contact models for the wheels. It will be shown that the multi-tiered approach enhances the simulation result accuracy compared to the results of a homogeneous model with a low level of detail while speeding up the simulation in comparison to a homogeneous higher tier model.
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...
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A numerically reliable computational approach based on descriptor systems techniques is proposed for the computation of the week generalized inverses of rational matrices. The main applications of the proposed method ...
A numerically reliable computational approach based on descriptor systems techniques is proposed for the computation of the week generalized inverses of rational matrices. The main applications of the proposed method are in solving model matching problems and in computing the inner-outer or J-inner-outer factorizations of rational matrices.
The design of a robust autoland controller using an optimization based design process is described. A modular controller architecture is developed first. Inner loops are based on Dynamic Inversion, speed and longitudi...
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This paper presents a novel Modelica library for physical modeling of switched reluctance machines. In order to deal with the nonlinear characteristics of switched reluctance drives, an analytical approximation functi...
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ISBN:
(纸本)9789881925121
This paper presents a novel Modelica library for physical modeling of switched reluctance machines. In order to deal with the nonlinear characteristics of switched reluctance drives, an analytical approximation function is applied when building a motor model. Furthermore, the look-up table based approach derived by the finite element method for computing the nonlinear model is also considered. Compared with other modeling approaches, physical modeling using the object-oriented modeling language-Modelica often exhibits a significant progress regarding model reusability, flexibility and range of modeling. One application example with a 16 stator 12 rotor poles 4 phase witched reluctance machine is presented to illustrate the use of the developed Modelica switched reluctance machine library.
This paper proposes a novel solution to the problem of pose estimation of three-dimensional objects using feature maps. Our approach relies on quaternions as the mathematical representation of object orientation. We i...
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We present a general Riccati theory for systems in descriptor form considered under the weakest possible assumptions imposed on the coefficent matrices. A Riccati-like equation of descriptor form is introduced and its...
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ISBN:
(纸本)9783952426906
We present a general Riccati theory for systems in descriptor form considered under the weakest possible assumptions imposed on the coefficent matrices. A Riccati-like equation of descriptor form is introduced and its stabilizing solution is characterized in terms of the associated extended Hamiltonian pencil (EHP) whilst the computation of such a solution is reduced to solving a generalized eigenvalue problem for a singular EHP. The results exposed in the paper are generalizations to the game-theoretic (sign indefinite) and singular cases of the (positivity) Riccati theory developed by several authors in the framework of descriptor systems. Possible applications range from various nonstandard and J-spectral factorizations to H2 and H∞ control of descriptor systems.
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.
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.
This paper describes the design of a manual flight controller, based upon nonlinear model-based control laws. These control laws include the previously developed concept of Pseudo Control Hedging (PCH). This PCH algor...
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