Papers by Keyword: Dynamic Modeling

Abstract: With the consideration of compressibility flow and the redefined load flow and load pressure, the mathematical model of long-stroke valve-controlled asymmetrical cylinder system is presented. The equivalent volume functions, the functions of equivalent volume functions of cylinder's two chambers are introduced, which reflects the influence of piston's positions in its long stroke on the dynamic performance of valve-controlled cylinder. Simulation results show that there exists obvious differences between forward and backward directions of long-stroke valve-controlled asymmetrical cylinder system, and its dynamic performance varies along the whole stroke, where the middle-stroke position may not always be the so-called most dangerous position.

Abstract: To provide theory and technique support for the research on dynamic properties of flexible lock-unlock technology, dynamic equation of band is built up based on the muti-body dynamics. Simulation based on modal neutral file and mixed model with rigid and flexible properties are accomplished in the software of ADAMS. The result reveals that the later one is much closed to the actual movement.

Abstract: CNC machine tool dynamic thermal error compensation has always been a hot issue to improving precision. This dissertation proposes a method of machine tool thermal error modeling during processing, based on Bayesian network theory, by describing the correlation between the various factors of generated the heat error, through the sample data, analyzed and simplified the intrinsic correlation between these various factors, established the basic thermal error compensation model, and used the network’s good characteristic of self-studying, combining the result of update collection data, continually modify the model to reflect the machining process condition changes. Finally, the experimental results show the feasibility of Bayesian network model, it was a stronger application for achieving the thermal error compensation.

Abstract: The modeling and sea trials of the Unmanned Trimaran Vehicles (UTSV) are presented in this paper. For control design, six DOF dynamic modeling of autonomous Trimarans is presented. The detailed mathematical modeling is intended to provide the appropriate framework for a control design which explicitly addressed the six DOF UTV dynamics. A control system was developed based on backstepping to guide the vessel to track desired trajectories based on the input of the sensors. Physical experiments were conducted to determine the maneuvering property of UTV.

Abstract: Morphing wings for winged tactical missile are gaining increasing concern for their potential to improve flight performance. However, morphing wings bring some new challenges to modeling flight dynamics due to movable components. This paper develops a set of complete nonlinear model, where some additional inertial terms are included. These terms account for the impact of morphing wing on flight states and make it difficult to study dynamic characteristics of missile. Therefore, a simplified model is deduced based on some reasonable assumptions. As a result, a longitudinal dynamic model is decoupled from the complete model. To verify the model, a numerical simulation is completed. The results show that the speed of wing changing has a notable effect on motion parameters during transition from one configuration to another, that is, the rapid wing changing means the larger amplitude and the higher frequency of motion vibration.

Abstract: According to the actual characteristics of semi-steel steelmaking of PZH steel, a static model for prediction of the oxygen blow amount and consumption of auxiliary material is established, and an end-point prediction model based on carbon content and temperature of sublance is given. This paper introduced the calculating principle and basic structure about above two models detailed. The results show that, the static model has certain accuracy and reliability of these models are illustrated by actual application.The static model might provide immediately the predicting optimum auxiliary material amount and the oxygen blow amount for operator, which direct the operation in time. The end-point prediction model might give real time prediction for the carbon content and temperature on BOF Endpoint, which has high hitting ratio.

Abstract: The system produces strenuous vibration when the wind turbine is operating, it will be a great impact on running precision and components’ life of the whole system, the theoretical study of the research of wind turbine’s vibration is incomplete because of the complexity of the wind turbine’s structure and operating environment, as well as the difficulty of theoretical analysis. In this paper, the FAST established dynamic model of wind turbine, and preliminarily study the establishment of the wind turbine drive system model with multi-body dynamics software, finally dynamic response have been analyzed that based on the establishment of whole wind turbine model, which laid the foundation for wind turbine dynamic characteristic and the system’s optimal design.

Abstract: Regarding 1100mm rolling mill hydraulic AGC system as the research object, on the basis of considering the pipeline dynamic characteristics and adopting position-pressure compound control method, the mathematical model of the hydraulic system is established. This paper analyzes the system dynamic characteristics in different conditions and studies the various static and dynamic error compensation methods.

Abstract: In this paper, a two-stage optimization approach for structural dynamic design was proposed on the basis of Component Mode Synthesis (CMS in short) technique. To improve the convergence of the optimization, the optimization was decomposed to two stages, i.e. the global and the local stages. The dynamic performance of the global assembled structures was optimized at the global stage by minimizing the total mass, taking the position of nodes as design variables. At the local stage, the performance of the local components was optimized by keeping the component mass less than the initial value, and getting the performance of the global structure improved. The CMS technique was integrated in the optimization to reduce the modeling cost and to determine the objective function of the local stage optimization. The dynamic optimization of the metal structure of an escalator was taken as an example to illustrate the feasibility and effectiveness of the proposed approach.

Abstract: Internal parallel moving gears transmission is a new type of planetary transmission with small tooth number difference. The dynamic model of the system is established by using lumped mass method. In the modeling process, the factors including the elasticity of all eccentric shafts, the elasticity of planetary bearing, the elasticity of supporting bearing on output shaft and the elasticity of meshing gears are considered, and the coordinate relation of the system is derived. The practical example and computer simulation was carried out and the dynamic characteristic is obtained. The results show that the gear transmission becomes steadier when simultaneously inputting the power from the three symmetrical shaft and utilizing multi-phase parallel mechanism, and the load of supporting bearing can be greatly reduced. This paper offers theoretical basis on correctly designing internal parallel moving gears transmission, reducing moving load and extending the service life.