Entity

Time filter

Source Type

Ankara, Turkey

Roketsan is a major Turkish weapons manufacturer and defense contractor based in the central Anatolian province of Ankara. Incorporated in 1988 by Turkey's Defense Industry Executive Committee in order to establish the nation's industrial base on rocket technology, the company has quickly risen to become one of Turkey's top 500 industrial establishments. Roketsan's current share holders include TSKGV , Aselsan , MKEK , Kalekalıp , Vakıflar Bankası , Kutlutaş and Havelsan . Roketsan is best known for its vast range of unguided rockets as well as laser and infrared guided missiles such as Cirit and UMTAS. The company also produces subsystems for Stinger and Rapier missiles and provides technology and engineering solutions for other integrated civilian and military platforms.In 2013 Turkey approved the construction by Roketsan of its first satellite launching center, initially for low earth orbit satellites.Roketsan is the only Turkish company to have obtained CMMI/ DEV 3 approval for all its design and development processes. Wikipedia.


Yumusak M.,Roketsan
Computers and Fluids | Year: 2013

The objective of this study is to develop a design tool that can be used in viscous flows. The flow analysis is based on the axisymmetric Navier-Stokes and k-e{open} turbulence equations. These coupled equations are solved using an explicit finite difference method. The accuracy of the analysis code is validated for viscous flows in solid rocket motor combustion chamber and nozzle. The gradient-based numerical optimization model is used to maximize the thrust of solid rocket motor under a constraint of propellant weight. The sensitivity analysis that measures the response of the flow with respect to a geometry perturbation is calculated by finite differencing. The optimization of design study employs a commercial optimization package. The performance of design optimization method is tested in solid rocket motor combustion chamber and nozzle design. © 2013 Elsevier Ltd. Source


Ates H.U.,Roketsan
2016 AIAA Guidance, Navigation, and Control Conference | Year: 2016

A novel nonlinear impact angle guidance law for stationary targets, based on Lyapunov stability theory, is proposed in this work. Unlike the previous works, proposed guidance law generates necessary acceleration commands perpendicular to the velocity vector based on controlling nonlinear line-of-sight dynamics between target and pursuer. The nonlinear dynamics of the line-of-sight angle and its rate are derived in the planar engagement geometry. The line-of-sight angle is aimed to be controlled to satisfy impact angle constraints. Qualitative studies show that pursuer follows a straight line trajectory at the end of the flight for stationary targets. Thus, the impact angle constraints can be satisfied via controlling line-of-sight angle. A sliding manifold which reduces the order of the system and controls both line-of-sight angle and rate with exponential stability is introduced. Then, the system is forced to slide on defined manifold based on Lyapunov stability theory. The necessary commands are analytically calculated. Finally the comparison with different impact angle control guidance laws are performed to summarize the proposed guidance law performance. © 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. Source


Cimen T.,Roketsan
Journal of Guidance, Control, and Dynamics | Year: 2012

Survey of state-dependent Riccati equation (SDRE) in Nonlinear optimal feedback control synthesis is presented. The aim is to reflect the rapid growth and strong interest in the field of SDRE paradigm by providing control theoreticians and practitioners with a balance between the theoretical developments, systematic design tools, and real-time implementation prospects of SDRE control methodology. In dealing with internal parameter variations, the ability of SDRE design methods to adapt controller gains in real time based on the SDC pair can be viewed as an equivalent approach to the adaptive control design paradigm. The SDRE method avoids cancellations due to the suboptimality property of the method. Extensive simulation results also show that SDRE controllers exhibit robustness against parametric uncertainties/variations and unmodeled dynamics, and they attenuate disturbances. Source


Gamze Karsli N.,Kocaeli University | Yesil S.,Roketsan | Aytac A.,Kocaeli University
Composites Part B: Engineering | Year: 2014

The hybrid reinforcement effect of surface treated or untreated carbon nanotube (CNT)/glass fiber (GF); on the morphology, mechanical and electrical properties of polypropylene matrix composites were investigated. Surface treatment of the CNTs was performed by using 3-Amino propyl tri ethoxy silane (APTES). Composites were prepared by means of extrusion and injection molding techniques. FT-IR analysis of the CNT samples revealed the successful surface modification of nanotubes after silane treatment. XRD results showed that chemically functionalized carbon nanotubes have the same cylinder wall and crystalline structure with untreated carbon nanotubes. Tensile and dynamic mechanical analysis (DMA) test results revealed that GF and nanotube reinforced hybrid composites exhibited better tensile strength and modulus values than only GF or CNT reinforced composites. According to all these results, it can be concluded that simultaneous usage of glass fiber and carbon nanotube in the composites increases the reinforcing ability of nanotubes in polymer composites. © 2014 Elsevier Ltd. All rights reserved. Source


Since the 1990s, state-dependent Riccati equation (SDRE) strategies have emerged as general design methods that provide a systematic and effective means of designing nonlinear controllers, observers and filters. These methods overcome many of the difficulties and shortcomings of existing methodologies, and deliver computationally simple algorithms that have been highly effective in a variety of practical and meaningful applications in very diverse fields of study. These include missiles, aircraft, unmanned aerial vehicles, satellites and spacecraft, ships, autonomous underwater vehicles, automotive systems, biomedical systems, process control, and robotics, along with various benchmark problems, as well as nonlinear systems exhibiting several interesting phenomena such as parasitic effects of friction and backlash, unstable nonminimum-phase dynamics, time-delay, vibration and chaotic behavior. SDRE controllers, in particular, have become very popular within the control community, providing attractive stability, optimality, robustness and computational properties, making real-time implementation in feedback form feasible. However, despite a documented history of SDRE control in the literature, there is a significant lack of theoretical justification for logical choices of the design matrices, which havedepended on intuitive rules of thumb and extensive simulation for evaluation and performance. In this paper, the capabilities and design flexibility of SDRE control are emphasized, addressing the issues onsystematic selection of the design matrices and going into detail concerning the art of systematicallycarrying out an effective SDRE design for systems that both do and do not conformto the basic structureand conditions required by the method. Several situations that prevent the direct application of the SDRE technique, such as the presence of control and state constraints, are addressed, demonstrating how these situations can be readily handled using the method. In order to provide a clear understanding of the proposed methods, systematic and effective design tools of SDRE control are illustrated on a singleinverted pendulum nonlinear benchmark problem and a practical application problem of optimally administering chemotherapy in cancer treatment. Lastly, real-time implementation aspects are discussed with relevance to practical applicability. © Since the 1990s, state-dependent Riccati equation (SDRE) strategies have emerged as general design methods that provide a systematic and effective means of designing nonlinear controllers, observers and filters. These methods overcome many of the difficulties and shortcomings of existing methodologies, and deliver computationally simple algorithms that have been highly effective in a variety of practical and meaningful applications in very diverse fields of study. These include missiles, aircraft, unmanned aerial vehicles, satellites and spacecraft, ships, autonomous underwater vehicles, automotive systems, biomedical systems, process control, and robotics, along with various benchmark problems, as well as nonlinear systems exhibiting several interesting phenomena such as parasitic effects of friction and backlash, unstable nonminimum-phase dynamics, time-delay, vibration and chaotic behavior. SDRE controllers, in particular, have become very popular within the control community, providing attractive stability, optimality, robustness and computational properties, making real-time implementation in feedback form feasible. However, despite a documented history of SDRE control in the literature, there is a significant lack of theoretical justification for logical choices of the design matrices, which have depended on intuitive rules of thumb and extensive simulation for evaluation and performance. In this paper, the capabilities and design flexibility of SDRE control are emphasized, addressing the issues on systematic selection of the design matrices and going into detail concerning the art of systematically carrying out an effective SDRE design for systems that both do and do not conformto the basic structure and conditions required by the method. Several situations that prevent the direct application of the SDRE technique, such as the presence of control and state constraints, are addressed, demonstrating how these situations can be readily handled using the method. In order to provide a clear understanding of the proposed methods, systematic and effective design tools of SDRE control are illustrated on a singleinverted pendulum nonlinear benchmark problem and a practical application problem of optimally administering chemotherapy in cancer treatment. Lastly, real-time implementation aspects are discussed with relevance to practical applicability. © 2010 Elsevier Ltd. Source

Discover hidden collaborations