Assembled PTO based on an array of double-acting hydraulic cylinders for WECs: From Conceptual Design to an Adjusted Detailed Model

All Wave Energy Converters (WECs) based on wave activated bodies comprises a Power Take- Off (PTO) system among other subsystems like the reaction mechanism, the supervisor of the system and the electrical generator. One of the most applied PTO systems consists of oil high pressure hydraulic devices. These devices are able to apply high forces, to store large quantities of energy through accumulators and to provide smoother power output to the motor coupled to a generator. In these systems the poor efficiency and the oil leakages contaminating the environment are considered main drawbacks. Despite of this, they are widely used in several promising WECs with the aim of optimizing the harvested wave energy along the time. The initial challenge to absorb an oscillating movement of ±30º at 5rad/s as a maximum angular speed absorbing up to 16000Nm from a specific WEC, led to the development of a simplified hydraulic model before manufacturing a PTO prototype to be verified in a Test Bench (Figure 1). The experimental results of PTO under different conditions have been used to adjust a full detailed PTO Model using Mathworks® software platform. This work presents a patented oil high pressure hydraulic PTO prototype based on an array of four double-acting hydraulic cylinders. This prototype has been designed and completely modelled as a proof concept at 1:4 scale being able to apply a variable Coulomb type damping torque through the activation of each hydraulic cylinder independently and through the modification of geometrical parameters easily. The complete model of the PTO has been accurately tuned up through adjustment of model parameters using the results of the experimental tests. This will allow the study of control strategies to optimize the extracted wave energy from a specific WEC, like point-absorbers

Control de power take-off para aprovechamiento de energía marina

262 p.Esta tesis describe un nuevo PTO hidráulico basado en un array de cilindros de doble efecto cuya fijación mecánica es variable, siendo todos ellos manipulables independientemente. Este PTO no lineal se modela cinemática y dinámicamente en detalle, incluyendo gran parte de las pérdidas y efecto hidráulicos, como las tuberías de transmisión o el aire atrapado en el fluido hidráulico. El comportamiento del PTO se verifica ante varios estados característicos de un componente principal del PTO, la válvula de control, mostrando la versatilidad del PTO diseñado. El modelo se ajusta al comportamiento real del PTO fabricado a través de ensayos experimentales en un banco de ensayos desarrollado a tal efecto. Para comprobar la extracción de energía del dispositivo PTO se incluye éste en un modelo de captador tipo absorbedor puntual aplicando varias estrategias de control. Las estrategias analizadas se corresponden con estrategias por amortiguamiento lineal, amortiguamiento de Coulomb y amortiguamiento basado en el auto bloqueo del captador por el propio PTO, ya sea a través del control del desplazamiento o del control del desplazamiento y velocidad del convertidor. Estas estrategias de control se analizan para condiciones de mar regular

A Power Take-Off Behaviour at High Pressure Operation Point, Using Four Double-acting Hydraulic Cylinders Modelled by a Port-based Approach

This paper deals with the behaviour at high pressure operation points of a hydraulic Power Take-Off (PTO) using a highly detailed model based on four double-acting hydraulic cylinders modelled by a port-based approach. The developed model takes advantage of the availability of basic hydraulic components which can be parameterized based on real ones, including most of the hydraulic losses. With the aim of optimizing the extraction of wave energy, this PTO is able to modify its restraining torque through the independent activation of the hydraulic cylinders located in the primary transmission and modifying some geometrical parameters related to their fixation points respecting to the axis torque. The ultimate objective of this PTO is to provide a wide range of torques that can be modulated by modifying the operating high pressure of the HP accumulator, the combination of the available areas of the double-acting hydraulic cylinder and the location of their fixation points with respect to the applied movement. This factor can help to improve the control of WEC based on activated bodies with the aim to optimize the extraction of wave energy. In this paper an extended simulation results at different operation points and input movements are presented.Regional Government of the Basque Country IT719-B, UPV/EHU UFI11/2

Construction of a Universal Hydraulic Power Take-Off for Wave Energy Converters. Mathematical Modelling and Validation Testing

This paper presents the construction, mathematical modelling and validation testing of a scaled universal hydraulic Power Take-Off (PTO) device for Wave Energy Converters (WEC). A specific prototype and test bench were designed and built to carry out the validation tests. The results obtained by these tests were used to adjust an in-house mathematical model. The design of the PTO device led to an international patent application. The PTO was initially designed to be coupled to a scaled wave energy capture device with a low speed and high torque oscillating motion and high power fluctuations. Any energy capture device (ECD) that fulfils these requirements can be coupled to this PTO, provided that its scale is adequately defined depending on the rated power of the full scale prototype. The initial calibration included estimation of the pressure drops in the different components, the pressurization time of the oil inside the hydraulic cylinders and the volumetric efficiency of the complete circuit. Since the overall efficiency measured during the tests ranged from 0.69 to 0.8 and the dynamic performance of the PTO was satisfactory, the results are really promising and it is believed that this solution might prove effective in real devices.Spanish Government PS-440000-2008-

Innovative Hydraulic Power Take-Off Construction and Performance Tests for Wave Energy Conversion

This document describes and demonstrates the features of a new innovative hydraulic Power take-Off (PTO) to be used for Wave Energy Conversion. This device is able to transform low frequency oscillating movement into a continuous high frequency angular speed, absorbing high fluctuated torque at the input shaft, which can reach up to 8000Nm. Moreover, the major breakthrough of this device is that it can control the braking torque through the modification of some geometrical parameters, L and R, and through the activation of more than one hydraulic cylinder together with the pressure. The output shaft of the PTO is able to rotate at different continuous rated speed through the actuation on a specific control valve at the inlet of the hydraulic motor. Tests to check the behavior of the PTO related to the smoothening of the power output and concerning the time needed to increase the high pressure and the time available after the accumulation of some quantity of energy in different initial conditions are presented.Spanish Government PS-440000-2008-

End-effector for automatic shimming of composites

Gaps in composite structures are a risky factor in aeronautical assemblies. For mechanically joined composite components, the geometrical conformance of the part can be problematic due to undesired or unknown re-distribution of loads within a composite component, with these unknowns being potentially destructive. To prevent unnecessary preloading of a metallic structure, and the possibility of cracking and delamination in a composite structure, it is important to measure all gaps and then shim any gaps greater than 127 microns. A strategy to overcome the high relative tolerances for assemblies lies in the automated manufacturing of shims for the gaps previously predicted through the evaluation of their volumes via a simulation tool. This paper deals with the development of a special end-effector prototype to enable the shimming of gaps in composites structures using a pre-processed geometry. The aim of this end-effector is to provide movement to a temperature controlled hot-end in order to generate a solid shim of ABS on the target composite surface. This process is defined according to the trajectories and velocities marked by the 3D printing process using standard G-code. The geometry and material volume to be printed are indicated by the simulated gap volume which is based on previous metrological measurements. The final objective will be to attach this end-effector to an anthropomorphic robot to enable autonomous manufacturing. This work is part of the EU FP7 funded LOCOMACHS project, under grant agreement n◦314003.European Union Seventh Framework Programme FP7/2007-2013 under grant agreement n° 314003; Basque program Elkartek Basqtech 201

Digital industrial furnaces: Challenges for energy efficiency under VULKANO project

Under intensive industry, industrial furnaces must cope with new challenges to improve the efficiency, reliability and flexibility of their processes. As they need a great amount of energy to achieve the temperature required for heating and melting processes, many researchers have been focused on the minimization of the energy consumption. This energy optimization implies improvements, not only in the competitiveness, but also in environmental and cost performances of the process. This paper shows briefly the challenges for industrial furnaces under VULKANO project focused on the development of five approaches from the point of view of efficiency, flexibility, reliability and safety: improving refractories, investigating new recovery systems based on PCM, using alternative fuels, integrating advanced monitoring and control devices and, finally, developing a holistic tool to help the operator to make decisions. Besides, this paper describes the creation of a digital industrial furnace, regarding to digital twin term. Therefore, an analytical model comprising the burners system, the isolation structure, an energy recovery system, and the load to be heated is described. Each individual model provides the base for the development of future hybrid models, accurately parametrized through process variables, used to investigate the efficiency optimization and provide precise maintenance operation strategies.The authors wish to acknowledge the financial support from the European Union under grant agreement n° 723803-VULKANO H2020-IND-CE-2016-17/H2020-SPIRE-2016. This publication reflects only the author’s views and the Union is not liable for any use that may be made of the information contained therein

Compact and cost effective instrument for detecting drug precursors in different environments based on fluorescence polarization

Several techniques for detecting chemical drug precursors have been developed in the last decade. Most of them are able to identify molecules at very low concentration under lab conditions. Other commercial devices are able to detect a fixed number and type of target substances based on a single detection technique providing an absence of flexibility with respect to target compounds. The construction of compact and easy to use detection systems providing screening for a large number of compounds being able to discriminate them with low false alarm rate and high probability of detection is still an open concern. Under CUSTOM project, funded by the European Commission within the FP7, a stand-alone portable sensing device based on multiple techniques is being developed. One of these techniques is based on the LED induced fluorescence polarization to detect Ephedrine and Benzyl Methyl Keton (BMK) as a first approach. This technique is highly selective with respect to the target compounds due to the generation of properly engineered fluorescent proteins which are able to bind the target analytes, as it happens in an “immune-type reaction”. This paper deals with the advances in the design, construction and validation of the LED induced fluorescence sensor to detect BMK analytes. This sensor includes an analysis module based on high performance LED and PMT detector, a fluidic system to dose suitable quantities of reagents and some printed circuit boards, all of them fixed in a small structure (167mm x 193mm x 228mm) with the capability of working as a stand-alone application.European Commission´s FP

Robot Coordination: Aeronautic Use Cases Handling Large Parts

The coordination of two collaborative robots to handle and hold huge parts is the main topic of this research. This study shows how flexible systems may accommodate large-volume components while situating components with a displacement precision between robots of no more than 10 mm into the parts, with the assistance of a single operator. The robots must be able to keep the parts in place while coordinating their movements to handle the parts and reducing external stressors. This paper suggests using collaborative robots to integrate flexible tools for adaptability to various elements in order to accomplish this goal without endangering the operators. The software architecture is described in full in this paper, including machine states to choose task executions, robot referencing in the workspace, remote monitoring via the digital twin, generation paths, and distributed control using a high-level controller (HLC)