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73rd International Astronautical Congress, IAC 2022

作者： Vivek, S. Vinayaravi, R. Tripathi, Suryamani Vasudevan, R. Asraff, A.K. Thermo-structural Analysis Division Structural Dynamics and Analysis Group Mechanical Design and Analysis Entity Liquid Propulsion Systems Centre Thiruvananthapuram695547 India Flow Control Valves Division Control Systems Valves Modules and Umbilical Group Control System and Components Entity Liquid Propulsion Systems Centre Thiruvananthapuram695547 India Structural Dynamics and Analysis Group Mechanical Design and Analysis Entity Liquid Propulsion Systems Centre Thiruvananthapuram695547 India Mechanical Design and Analysis Entity Liquid Propulsion Systems Centre Thiruvananthapuram695547 India

For propelling new generation Indian launch vehicles, ISRO is developing a liquid oxygen-kerosene based high thrust rocket engine. In liquid rocket engines, bolted flange joints are critical components and leak tightness is to be ensured for all bolted joints for safe operation. For the same reason, various metallic seals are employed and "lambda" (λ) type seal is one among them. There is little information about this type of seals in literature and its geometry is uncommon and intricate. This seal, made of high strength stainless steel has 5 sealing faces and interfaces of mating flanges are spherical in nature. Bolted joint investigated in this study is located at the inlet of an injection valve. Extensive nonlinear finite element simulations were carried out for understanding the normal load variation at each of these sealing faces with increase in internal pressure. For validating the numerical model as well as to verify the seal performance, a simulator joint was designed and tested. Multiple tests were carried out to study the effect of temperature of operating medium on the seal behaviour. The results indicate that, both at cryogenic temperatures as well as at ambient conditions, lambda type seals can provide leak tightness at very high internal pressure with moderately low pre-load values and can accommodate large flange movements. Results are of high relevance for finalizing the preload values for similar bolted joints in flight hardware. © 2022 International Astronautical Federation, IAF. All rights reserved.

关键词： Bolted joints

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Active Reduction of Transient Driveline Oscillations with Fuzzy Update Timings of control Input

Active Reduction of Transient Driveline Oscillations with Fu...

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International Conference on control, Mechatronics and Automation (ICCMA)

作者： Heisei Yonezawa Ansei Yonezawa Takashi Hatano Shigeki Hiramatsu Chiaki Nishidome Itsuro Kajiwara Division of Mechanical and Aerospace Engineering Hokkaido University Hokkaido Japan Division of Human Mechanical Systems and Design Hokkaido University Hokkaido Japan Integrated Control System Development Division Mazda Motor Corporation Hiroshima Japan CATEC Inc. Tokyo Japan

ISBN: (纸本)9781665490498

In active vibration suppression for automotive drivelines, this research presents an effective fuzzy inference compensation for the time-varying long control cycle limitation. First, a simplified driveline model with the control cycle limitation is provided for investigating active damping strategy. As a baseline damping strategy, a sampled-data H ∞ controller is used to mitigate effects of discretization errors due to the long control cycles. In addition, the control cycles force the control input updating timing of the actuator to be perturbed from that of the fixed periodical controller. The core idea of the compensation is to regard these uncertain timings as fuzzy sets such as "Approximately past timing" and "Approximately future timing". The proposed fuzzy logic simply computes feasible damping commands at various timings based on Mamdani-type reasoning with a few rules. Through simulation tests with various situations, the superior robustness of the proposed method is confirmed.

关键词： Vibrations Damping Fuzzy logic Mechatronics Robustness Timing Indexes

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Corrigendum to “Weight minimisation of displacement-constrained truss structures using a strain energy criterion” [Comput. Methods Appl. Mech. Engrg. 191 (2002) 2159–2177]

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Computer Methods in Applied Mechanics and Engineering 2021年 383卷

作者： Panagiotis A. Makris Christopher G. Provatidis National Technical University of Athens School of Mechanical Engineering Mechanical Design and Control Systems Division 9 Heroon Polytechniou Str. 15780 Zografos Greece

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Cooperative Lane Change Motion Planning of Connected and Automated Vehicles: A Stepwise Computational Framework

Cooperative Lane Change Motion Planning of Connected and Aut...

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2018 IEEE Intelligent Vehicles Symposium, IV 2018

作者： Zhang, Youmin Li, Bai Zhang, Yue Jia, Ning Shaanxi Key Laboratory of Complex System Control and Intelligent Information Processing Xi'An University of Technology Xi'an710048 China Division of Systems Engineering Center for Information and Systems Engineering Boston University Boston United States Department of Mechanical Industrial and Aerospace Engineering Concordia Institute of Aerospace Design and Innovation Concordia University Montreal Canada Institute of Systems Engineering Tianjin University Tianjin China

ISBN: (纸本)9781538644522

This paper focuses on the scheme of cooperative lane change motion planning of multiple connected and automated vehicles, so as to minimize the time for lane change while penalizing large steering angles subject to hard collision avoidance constraints. Nominally this scheme should be formulated in a centralized way with the constraints of all the vehicles considered simultaneously. In order to facilitate the numerical solving process of this centralized optimization problem, we propose a stepwise computation framework. Starting with a sub-problem with all of the collision avoidance constraints removed, a sequence of sub-problems are defined by adding back the removed collision avoidance constraints gradually until the original problem takes shape in the end. The optimum of one sub-problem is always used as the initial guess when solving the next sub-problem. This iterative process continues until the optimum of the original problem is obtained. In this way, the difficulties in the original centralized problem are divided into multiple parts, and every progress made to address the partial difficulties is 'solidified' by the initial guess. © 2018 IEEE.

关键词： Collision avoidance

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Near-Optimal Online Motion Planning of Connected and Automated Vehicles at a Signal-Free and Lane-Free Intersection

Near-Optimal Online Motion Planning of Connected and Automat...

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2018 IEEE Intelligent Vehicles Symposium, IV 2018

作者： Li, Bai Zhang, Youmin Zhang, Yue Jia, Ning Ge, Yuming Shaanxi Key Laboratory of Complex System Control and Intelligent Information Processing Xi'An University of Technology Xi'an710048 China College of Control Science and Engineering Zhejiang University Hangzhou310027 China Department of Mechanical Industrial and Aerospace Engineering Concordia Institute of Aerospace Design and Innovation Concordia University Montreal Canada Division of Systems Engineering Center for Information and Systems Engineering Boston University BostonMA02215 United States Institute of Systems Engineering Tianjin University Tianjin300072 China China Academy of Information and Communications Technology Beijing100191 China

ISBN: (纸本)9781538644522

In this paper, we propose a cooperative motion planning method for a group of connected and automated vehicles (CAVs) crossing a lane-free intersection without using explicit traffic signaling. This multi-vehicle motion planning task is formulated as a centralized optimal control problem. However, the solution to this optimal control problem is numerically intractable due to the high dimensionality of the collision-avoidance constraints and the nonlinearity of the vehicle kinematics. A two-stage strategy is proposed for generating online solutions: at Stage 1, the CAVs are requested to reach a standard formation before entering the intersection;at Stage 2, the vehicles cross the intersection. As the motion planning sub-problem at Stage 2 begins with a standard configuration, the optimal solution to this standard sub-problem can be computed offline in advance and applied online directly. On the other hand, the formation reconfiguration sub-problem at Stage 1 is easy to solve online. Through dividing the entire dynamic process into two periods, the difficulties in the original optimal control problem are significantly reduced so that the real-time performance is achieved. © 2018 IEEE.

关键词： Motion planning

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Time-optimal motion planning for n-DOF robot manipulators using a path-parametric system reformulation

Time-optimal motion planning for n-DOF robot manipulators us...

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American control Conference

作者： Robin Verschueren Niels van Duijkeren Jan Swevers Moritz Diehl Systems Control and Optimization Laboratory Department of Microsystems Engineering University of Freiburg Germany Division of Production engineering Machine design and Automation Department of Mechanical Engineering KU Leuven Belgium

ISBN: (纸本)9781467386838

Time-optimal motion planning for robotic manipulators consists of moving the robot along a path in Cartesian space as fast as possible. In contrast to time-optimal path following, small deviations from a predefined path are acceptable and can be exploited to further reduce the overall motion time. In this paper, we present a new method to compute time-optimal motions around a path. By employing an appropriate change of variables for the robot dynamics to path coordinates, geometric constraints enter the optimal control formulation in a convenient way. The reformulation of the robot dynamics and the path constraints is illustrated with numerical examples.

关键词： Robot kinematics Optimization Manipulators Dynamics Vehicle dynamics Optimal control Robot kinematics robot dynamics Manipulators Optimal control Vehicle dynamics motion planning Robot Manipulator dynamics Byways geometric constraint

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Integrated energy and power management: Validation testing for aerospace vehicles

Integrated energy and power management: Validation testing f...

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AIAA Modeling and Simulation Technologies Conference, 2016

作者： Yerkes, Kirk L. Pratt, David M. Doty, John H. van Muijden, Jaap Eussen, Bart J. G. Wu, Thomas Flight Systems Integration Branch Power and Control Division Air Force Research Laboratory Aerospace Systems Directorate WPAFB OH United States Design and Analysis Branch Aerospace Vehicles Division Air Force Research Laboratory WPAFB OH United States Department of Engineering Management and Systems University of Dayton 300 College Park DaytonOH United States National Aerospace Laboratory NLR AmsterdamCM1059 Netherlands Department of Flight Physics and Loads Aerospace Vehicles Division P.O. Box 90502 BM1006 Netherlands Department of Mechanical and Aerospace Engineering University of Central Florida 4000 Central Florida Blvd OrlandoFL32816 United States

ISBN: (纸本)9781624103872

The structured technical and organizational approach to integrated dynamic energy and power management research is outlined from an integrated vehicle and dynamic subsystem/component perspective. This approach combines physics-based and statistical modeling and component and system validation testing on baseline airframe(s) in a flight simulated environment. It is concluded that experimental data of individual system component tests are not alone sufficient. Laboratory tests on an integrated airframe with interacting subsystems are needed to properly define requirements for effective validation testing needed to support robust model-based engineering and life-cycle growth management. The objective is to develop and demonstrate a robust validation testing approach that transcends beyond the component-only focus to one that addresses the vehicle in its entirety and throughout the vehicle life-cycle. © 2016, American Institute of Aeronautics and Astronautics Inc. All rights reserved.

关键词： Structural frames

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Wave based design optimisation of composite structures operating in dynamic environments 5

Wave based design optimisation of composite structures opera...

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5th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, COMPDYN 2015

作者： Chronopoulos, D. Collet, M. Ichchou, M. Antoniadis, I. Division of Materials Mechanics and Structures University of Nottingham University Park NG7 2RD United Kingdom LTDS UMR-CNRS 5513 36 Avenue Guy de Collongue Ecully69130 France Ecole Centrale de Lyon 36 Avenue Guy de Collongue Ecully69130 France Machine Design and Control Systems Section School of Mechanical Engineering National Technical University of Athens Greece

The optimal mechanical and geometric characteristics for layered composite structures subject to vibroacoustic excitations are derived. A Finite Element description coupled to Periodic Structure Theory is employed for the considered layered panel. Structures of arbitrary anisotropy as well as geometric complexity can thus be modelled by the presented approach. Initially, a numerical continuum-discrete approach for computing the sensitivity of the acoustic wave characteristics propagating within the modelled periodic composite structure is exhibited. The first and second order sensitivities of the acoustic transmission coefficient expressed within a Statistical Energy Analysis context are subsequently derived as a function of the computed acoustic wave characteristics. Having formulated the gradient vector as well as the Hessian matrix, the optimal mechanical and geometric characteristics satisfying the considered mass, stiffness and vibroacoustic performance criteria are sought by employing Newton's optimisation method.

关键词： Periodic structures

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A receding horizon control approach to synchronization for chaotic systems

A receding horizon control approach to synchronization for c...

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ICROS-SICE International Joint Conference 2009, ICCAS-SICE 2009

作者： Choon, Ki Ahn Jung, Hun Park Moon, Kyu Song Chul, Dong Lee Division of Electronic and Control Engineering Wonkwang University Iksan Korea Republic of BK21 School for Creative Engineering Design of Next Generation Mechanical and Aerospace Systems Seoul National University Seoul Korea Republic of Jeonbuk Embedded System Research Center Korea Electronics Technology Institute Korea Republic of

ISBN: (纸本)9784907764333

In this paper, we propose a receding horizon control approach to synchronization for chaotic systems. A new matrix inequality condition on the terminal weighting matrix is proposed for chaotic systems under which nonincreasing monotonicity of the optimal cost is guaranteed. It is shown that the proposed terminal inequality condition guarantees the closed-loop stability of the receding horizon synchronization (RHS) method for chaotic systems. As an application of the proposed method, the RHS problem for Chua's chaotic system is investigated. © 2009 SICE.

关键词： Linear matrix inequalities

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Application of vehicle seat vibrator using electric actuator control algorithm

Application of vehicle seat vibrator using electric actuator...

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International Conference on control, Automation and systems, ICCAS 2007

作者： Kim, Kyoung Dal Lee, Seung Heui Park, Dong Woon Lee, Min Cheol Yoo, Wan Suk Intelligent Control and Automation Division Pusan National University Busan Korea Republic of Mechanical Systems Design Division Pusan National University Busan Korea Republic of School of Mechanical Engineering Pusan National University Busan Korea Republic of

ISBN: (纸本)8995003871

Vibration of real vehicle originates an engine drive and form of road surface. It begins a fatigue accumulation of vehicle driver, with technology for restraint to vibration of vehicle is going to research and application. The vehicle seat vibrator is a simulator for vibration of real vehicle reappears. Vehicle vibration generated of virtual experiment a driver feel in vibration area. The oil pressure type vehicle seat vibrator of préexistence is limiting a vibration test plan of small scale for make because of high cost;with vehicle seat vibrator using single electric actuator develops. It study analyses systems limit and dynamics of vehicle seat vibrator. And control algorithms apply electric actuator for vibration test. ©ICROS.

关键词： Virtual reality

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