For wind turbines, pitch control is essential. In some cases, especially in the case of large scale wind turbines, hydraulic control is used. In this paper a hydraulic system used in wind turbine pitch control is anal...
For wind turbines, pitch control is essential. In some cases, especially in the case of large scale wind turbines, hydraulic control is used. In this paper a hydraulic system used in wind turbine pitch control is analysed. Modelling and simulation of hydraulic systems is necessary in order to acknowledge the drawbacks and advantages before starting the design of the system. By acknowledging, the differences between the model of a physical system and a system in a virtual environment, one can handle the improvement, in terms of price or time-consumption. Considering the proposed diagram of the pitch control hydraulic system, it is presented the block diagram created in MATLAB Simscape Fluids. Some results of the simulation are presented. There are included conclusions and plans for future work.
The oscillation motions of physical pendula constructed with contacts between ball and cylindrical external surfaces for materializing the theoretical frictionless pivot point were applied for determining the coeffici...
The oscillation motions of physical pendula constructed with contacts between ball and cylindrical external surfaces for materializing the theoretical frictionless pivot point were applied for determining the coefficient of rolling friction (occurring as a characteristic of the relative motion between the contacting surfaces). The condition imposed for estimation of the coefficient of rolling friction consists in the requirement that the theoretical curve and the experimental data describing the decrease of angular amplitude should superpose each other. To be mentioned that specialized software for dynamic analysis characterizes the rolling friction by the internal damping of the contacting materials instead of applying the coefficient of rolling friction between the materials.
Microcapsules are used in a wide range of applications, especially in self-healing composite materials and phase change materials. There is a growing body of literature that recognizes the importance of reinforcement ...
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We present an extensive formulation of the inverse grating problem for flexural waves, in which the energy of each diffracted mode is selected and the grating configuration is then obtained by solving a linear system ...
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In this paper the problem of local minimum in obstacle avoidance is solved using improved follow gap method (FGM) through combination with genetic programming (GP). Two stages of controller are proposed and applied on...
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In this paper the problem of local minimum in obstacle avoidance is solved using improved follow gap method (FGM) through combination with genetic programming (GP). Two stages of controller are proposed and applied on Robotino mobile robot equipped with nine infrared sensors. The first stage implements FGM when there is a gap between front obstacles whereas the second stage deals with the case of no front gap through the utilization of GP. Simulation and experimental work prove the effectiveness of the proposed method.
Adaptive inverse control（AIC） is an advanced control technology which can efficiently learn and control the severely nonlinear and real-time plant,such as the electrohydraulic shaking table（EST）.The foundation of ...
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Adaptive inverse control（AIC） is an advanced control technology which can efficiently learn and control the severely nonlinear and real-time plant,such as the electrohydraulic shaking table（EST）.The foundation of AIC is the system identification of the plant via an adaptive *** traditional adaptive filter theory is known as a fixed tap-length（length of the weight vector） FIR（Finite impulse response） filter whose weights change by adaptive algorithm *** mismatch between plant and the fixed taplength will cause inaccuracy or compute *** paper introduce a variable tap-length NLMS（VTLNLMS） algorithm to find the optimum tap-length（OPTL） of the model of multi-DOF EST,then use AIC to improve the accuracy of time wave *** dynamics response nonlinear model of the EST is built to reflect the experimental *** nonlinear EST model and referred algorithm are simulated in MATLAB/*** show the AIC with OPTL is effective in the EST.
With the universal application of camera in intelligent vehicles, visual place recognition has become a major problem in intelligent vehicle localization. The traditional solution is to make visual description of plac...
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Transformable structures in architecture have the ability to change morphology and readjust in response to varying conditions and needs that can include changing environment and climatic conditions, different function...
Transformable structures in architecture have the ability to change morphology and readjust in response to varying conditions and needs that can include changing environment and climatic conditions, different functional requirements and emergency situations. Depending on how the transformation is carried out, transformable structures can be deployable or demountable, as a kit-parts system. Deployable structures can also be classified in four main groups: spatial bar structures consisting of hinged bars; foldable plate structures consisting of hinged plates; tensegrity structures; and membrane structures. In this paper, a review on the deployable structures based on rigid bar mechanisms will be performed.
The residual stresses occur in the material structure of unloaded solid bodies, reflecting their technological path, together with the history of mechanical and thermal loads incurred during their operation. It is imp...
The residual stresses occur in the material structure of unloaded solid bodies, reflecting their technological path, together with the history of mechanical and thermal loads incurred during their operation. It is important to underline that the residual stresses in a solid body have always the effect of a balanced system of forces. When they overlap with the stresses involved by the loads for which the body is intended, it is sometime possible for that body to be taken out of operation. Experimental tests covered by this work aimed to highlight some possible degradation occurring during the operation for the railroad tracks called '85 and '86, in order to establish to what extent they may still be used for another time interval. In this context, the size of residual stresses was experimentally determined, in some samples taken from the studied railroad tracks, and also from a piece of unused railroad track, in order to compare the results. Moreover, an analysis was made, using the specifications of the standard SR EN 13674-1:2011, on the variation of stresses that occur in the material during the rails cutting.
A robotic manipulator should be able to obtain an arbitrary orientation of the end-effector, action which needs a wrist mechanism with minimum two independent rotations about two intersecting axes, generally perpendic...
A robotic manipulator should be able to obtain an arbitrary orientation of the end-effector, action which needs a wrist mechanism with minimum two independent rotations about two intersecting axes, generally perpendicular. If the task performed by the manipulator is more complex, it may be necessary for the end-effector to rotate about its axis, it means that the wrist mechanism needs three degrees of freedom. Planetary bevel-gear trains can be used in the design of wrist mechanisms. The wrist mechanisms using bevel gears have been shown to have some advantages. More, a nutating gear drivetrain has some advantages over a conventional planetary gear train, including: a decreased number of drivetrain parts, an ability to use lower-strength gear materials, a higher overall reliability, and a decreased manufacturing cost. Based on some nutation geared mechanisms using bevel internal gears having small difference in numbers of teeth, in this paper some robotic wrists will be proposed.
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