Real-time simulation models based on multibody system dynamics can replicate reality with high accuracy. As real-time models typically describe machines that interact with a complicated environment, it is important to have an accurate environment model in which the simulation model operates. Photogrammetry provides a set of tools that can be used to create a three-dimensional environment from planar images. A created environment and a multibody-based simulation model can be combined in a Unity environment. This paper introduces a procedure to generate an accurate spatial working environment based on an existing real environment. As a numerical example, a detailed environment model is created from a University campus area.
In co-simulation, a number of subsystems sharing details of a system, are coupled to exchange data. The subsystem level development of each package enhances the computational efficiency, and more sophisticated packages can be created. However, the data exchange is not always straight forward as different packages can be developed by different research or industrial centers. Therefore, some standards such as Functional Mock-up Interface (FMI) are developed to facilitate the data exchange in co-simulation or co-integration. In this work, the co-simulation approach is employed to investigate the effects of dissolved air on the dynamic performance of a hydraulically driven multibody system. To this end, the subsystems of multibody system dynamics and a hydraulic model are coupled by using the FMU procedure. The utilized FMUs are produced by using an XML model description and a C code for the hydraulic part. The multibody mechanism under investigation is a jib crane model containing three bodies. The model is studied by exciting different sine inputs having known frequencies while varying the amount of dissolved air in the hydraulic system. The results have illustrated that by increasing the amount of entrained air, the pressure amplitude decrease. In addition, the results demonstrated that the amount of the air does not have effects on shifting the system frequency.
This paper describes an estimator incorporating the Unscented Kalman Filter (UKF) technique and multibody system dynamics, to determine the state of the flexible multibody applications. The dynamic equation of the flexible mechanism is formed using a set of non-linear equations as functions of reference and modal coordinates. Since both reference and modal coordinates have no physical meaning, their information is not able to be obtained directly from sensors. Thus, a novel technique is proposed in this work that can successfully translate physical measurements collected by sensors into non-physical modal coordinates. To validate the performance of the proposed modeling technique to apply a UKF to determine the state of a nonlinear flexible multibody system, simulation were carried out for a four-bar mechanism case study to compare the simulation data and UKF data.INDEX TERMS Deflection, flexible simulation models, nonlinear Kalman filter, state observer, unscented Kalman filter.
This paper introduces a method for building a real-time simulation model with adjustable user-selected parameters. The proposed design process model consists of eight steps with four decision points. Parameterization is a technique enabling real-time simulation with different combinations of parameters. Currently, there is no unique way to incorporate user input and switch between model combinations. The proposed method is presented in the form of a flowchart. Based on the data, a 3D design of the model was constructed. Two alternative approaches were introduced to construct a parameterized real-time simulation model with user inputs. The approach used was selected based on the number of parameterized specifications. The feasibility of each case was analyzed analytically and by simulation. Finally, a version of the model was selected based on the given initial requirements. To illustrate the developed approach, an excavator model was selected for parameterization. In the excavator model, two parts are considered to have adjustable parameters: the bucket and the hydraulics. Each part has three options that can be selected by users. The approach enables easy adaptability of user-generated parameter inputs, thus permitting evaluation of multiple scenarios, while simultaneously maintaining realistic representation.
Introduction: Natural and human activities lead to soil degradation and soil salinization. In the last two centuries, world metal pollution level has increased extremely. The presence of some heavy metals in aquatic ecosystems is a constant threat to the health of human societies. The decrease of farmlands threatens food security. There are approximately one billion ha salt-affected soils all over of world, which can be utilizable after chemical, physical and biological remediation. Many mines in the world and also in Iran exist and as a result, soil erosion and dust release from waste dams is a matter of concern. Bioremediation using biological agents to detoxify and degradation of environmental pollutants provides a suitable alternative method for substitution of current heavy metals removal strategies. Material and methods:As a result of extraction operations by cyanidation in Mouteh gold mining complex, wastewater and waste soil sediment are widely achieved. In this study soil samples were collected from Mouteh Goldmine tailing dam soil in September 2018. The collected soil samples were cultured in BG11 medium and incubated for microalgae identification and biomass production. Also, 5 g soil was inoculated with 0.5 g biomass of cyanobacteria and the physicochemical characteristics of the soil including pH, Na, K, Pb, and Cd, before and after the inoculation of soil with cyanobacteria were determined. Results and discussion:In this study, cyanobacteria Phormidium tenue Gomont, Osillatoria tenuis C.Agardh ex Gomont, Lyngbya aestuarii Liebman ex Gomont and the green alga, Scenedesmus obliquus (Turpin) Kützing were identified. Culture results of filamentous cyanobacteria on goldmine tailing dam soil showed that
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