One of the greatest challenges of optimising the correct operation of wind turbines is detecting the health status of their core components, such as gearboxes in particular. Gearbox monitoring is a widely studied topic in the literature, nevertheless, studies showing data of in-service wind turbines are less frequent and tend to present difficulties that are otherwise overlooked in test rig based works. This work presents the data of three wind turbines that have gearboxes in different damage stages. Besides including the data of the SCADA (Supervisory Control And Signal Acquisition) system, additional measurements of online optical oil debris sensors are also included. In addition to an analysis of the behaviour of particle generation in the turbines, a methodology to identify regimes of operation with lower variation is presented. These regimes are later utilised to develop a health index that considers operation states and provides valuable information regarding the state of the gearboxes. The proposed health index allows distinguishing damage severity between wind turbines as well as tracking the evolution of the damage over time.
In this paper, a procedure for the kinematic design of a 3-PRS compliant parallel manipulator of 3 degrees of freedom is proposed. First, under the assumption of small displacements, the solid body kinematics of the 3-PRS has been studied, performing a comprehensive analysis of the inverse and forward kinematic problem, and calculating the rotations that the revolute and spherical flexure joints must perform. Then, after defining some design requirements and therefore the necessary displacements to fulfill, a design process based on the finite element calculations has been stablished, giving the necessary guidelines to reach the optimal solution on a 3-PRS compliant mechanism. Also, a prototype has been tested, using a coordinate measuring machine to verify its dimensions and the resulting displacements in the end effector and the actuated joints. Finally, those measurements have been compared with the FEM and the rigid body kinematics predictions, contrasting the validity of those two modelling approaches for the kinematic design of compliant mechanisms.
The final objective of this work is to reach a manipulator of 5 degrees of freedom which is capable of developing micromilling operations. It consists of a XY stage under a 3PRS compliant parallel mechanism, obtaining the advantages of the compliant joints as are higher repetitiveness, smoother motion and a higher bandwidth, due to the high precision demanded from the process, under 0.1 micrometers. In this work, the dynamics of the compliant stage will be developed. The modelling approach is based on the use of the Principle of Energy Equivalence combined with the Boltzmann-Hamel equations to analyze the rotational dynamics of the platform. A pseudo-rigid model has been assumed for the compliant joints, calculating the flexural and torsional stiffness by FEA. Finally, a prototype has been built and some preliminary results are shown comparing the simulation and the measurements.
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