An accurate dynamic model is a prerequisite for realizing precise control of industrial robots. The dynamics research of multi-degree of freedom (DOF) robots is relatively unexplored and needs to be solved urgently. In this paper, a dynamic modeling method of multibody system of 6-DOF robot is proposed based on the screw theory. The established dynamic model has a more concise and unified mathematical form, and the modular matrix expression is convenient for the control of the robot. In order to ensure that the screw method is suitable for motion in a wide range of angles, quaternions are used as generalized angular coordinates, and the model established thereby eliminates singularities and improves computational efficiency. The correctness and accuracy of the screw method is verified by the simulation example, and the modeling theory and method can provide a theoretical basis for the precise control of the robot.
In this paper, we investigate the dynamic case of optical grooming in flexible bandwidth optical networks, and propose a novel dynamic optical grooming algorithm called Consecutive Spectrum based Optical Grooming (CSOG). Simulation results show that the blocking probability can be reduced and resource utilization can be improved compared with non-grooming scenario.
Continuous powder blending is an essential operation during continuous pharmaceutical manufacturing. However, the complex granular dynamics in the blender is still poorly understood. This study employs a graphic processor unit (GPU) enhanced discrete element method (DEM) to analyse the granular dynamics in a continuous blender. Numerical results indicate that only a small fraction of powder distributes in the upper region of the blender, while most of that distributes in the middle and lower regions. Besides, a higher impeller speed leads to a smaller hold-up mass and a shorter mean residence time. Interestingly, the maximum number of blade passes is achieved at an intermediate impeller speed. There are two distinct regimes during continuous blending: i) a shearing regime at low impeller speeds; and ii) a dynamic regime at high impeller speeds. This study demonstrates that the GPU-enhanced DEM can be a robust tool for analysing powder flow during continuous pharmaceutical manufacturing.
Setting an openable light on the roof or the wall of a residence to control the entry of outside air and sunlight has been considered in relation to designing houses for comfort in Japan. The problem is that thermal gain through insolation can produce an unfavourable rise in the indoor air temperature (Ta). This is due to the characteristics of the Japanese climate. Japan has both a continental and an oceanic climate because of its topography which produces a high temperature and high humidity in summer, but low temperatures and low humidity in winter. The present study examines the effect on the interior thermal environment of an experimental residence through the thermal environment index, the predicted mean vote, the mean radiant temperature and the operative temperature when a toplight or side window is opened in the summer. This work aimed to study the conditions for lowering Ta and surface temperatures to simulate a comfortable interior thermal environment.
We can judge the diesel active state by measuring the turbo supercharger speed, but in practical measurement, there are always many problems. In this paper, we build the regression model of relationship between turbo supercharger speed and pressure ratio, intake flow, turbine final pressure, turbine front pressure, turbine final temperature, gas compressor final pressure, gas compressor front pressure and gas compressor front temperature by the partial least square and cross validity test. Through the test, the explanation ability for the independent variables and the dependent variables of the model exceed 99%. Comparing with the practical values, this model has higher fitting precision and better prediction ability. This method solves the problem of install difficulty during actual vehicle measuring and the low precision which has great significance to the actual vehicle test of diesel turbo supercharger in low temperature conditions.
The projection pursuit regression theory is applied to analysis the reliability of vehicle hydraulic brake system and build the projection pursuit regression model. This model on training sample fitting effect is good and shows extremely strong adaptability. We predict the reliability of certain type hydraulic brake system by this model which provides scientific basis for research on reliability of hydraulic brake system.
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