One of the major challenges facing wind energy at the moment is its dependence on dispatchable energy sources to match power supply to demand and provide an adequate spinning reserve. There is no fundamental impediment for this to be done with wind energy when wind conditions are such that sufficient wind power is available. It is, in fact, common for wind farms to participate in primary and secondary frequency regulation via droop curves, curtailment, synthetic inertia, proportional de-loading, and delta control. However, although the literature presents several approaches to turbine-level control functions of this sort, it is not trivial to extract from it a readily industrializable set of algorithms. Said extraction, focused on delta control and the addition of our own contributions, is the purpose of this paper, where we propose an extension of popular torque and pitch control algorithms, which allows delta control without the wind speed observers used by other authors.
The demand for collaborative robots is growing in industrial environments due to their versatility and low prices. Thus, more collaborative solutions are emerging for industrial scenarios. However, implementing scenarios where robots work autonomously while synchronizing their operations in a safe industrial environment with shop-floor workers is not easy. To fill the gap existing in the safe implementation of industrial collaborative scenarios, this manuscript presents a review based on five identified challenges that gathers the primary vital aspects to bear in mind while developing applications for them. Thus, a four-level classification is proposed, which collects the identified challenges and the previous developments in the field of human-robot interaction. The five identified challenges pretends to be the missing enabling key for implementing industrial collaborative scenarios in modern industrial plants. Lastly, a discussion and conclusion are exposed to analyze the degree of development in the field and its potential growth.
Industrial machines commissioning consumes a great amount of man-hours, due to control designers lack of knowledge about the final controller gains before they start working with it. Virtual commissioning has been postulated as an optimal solution to deal with this lack of knowledge when the Real-Time simulation of the digital models reproduces an identical behaviour as the industrial machines they represent. Cyber-Physical Systems (CPSs) offer new opportunities in this field, however, in the case of industrial machines, acquiring this level of accuracy requires to slow down the simulation. On this paper, novel modelling techniques for industrial CPSs have been presented. They are introduced to help in the evolution from conventional control design to a virtual commissioning process combining software and hardware capabilities. This methodology has been tested with a hydraulic-press model designed following manufacturer specifications, initially under a Software in the Loop (SiL) validation platform and, afterwards, in a Hardware in the Loop (HiL) validation platform. The control algorithms are designed in laboratory conditions harmless for the machine, embedding them later in the industrial environment without further modifications. INDEX TERMS Electrohydraulics, hydraulic systems, real time systems, system-level design, virtual manufacturing.
<p>Andalusia, the southern region of Spain, has an ancient history, magnificent monuments and a prolific culture. This region has developed an ambitious infrastructure improving plan, concerning every facility and mean of transport. Bridges have a preeminent role in all of these interventions, and their design needs to deal, in a very conscious way, with a rich natural environment and with an outstanding cultural heritage that configure the historic patrimony of the area. For all these reasons, it is appealing to analyse how to develop a bridge project in such an attractive and, at the same time, sensitive environment, especially in urban areas where the conjunction of nature and cultural heritage takes place. The study of a few representative examples is tackled, focusing in the key aspects involved in the achievement of a successful project, not only respecting the surrounding conditions, but also increasing the objective and subjective value of the place.</p>
An iterative learning control (ILC) algorithm is presented for the force control circuit of a hydraulic cushion. A control scheme consisting of a PI controller, feed-forward (FF) and feedback-linearization is first derived. The uncertainties and nonlinearities of the proportional valve, the main system actuator, prevent the accurate tracking of the pressure reference signal. Therefore, an extra ILC FF signal is added to counteract the valve model uncertainties. The unknown valve dynamics are attenuated by adding a fourth-order low-pass filter to the iterative learning control design, which is split up into two second-order low-pass filters to carry out forward and backward filtering and obtain zero-phase filtering. The addition of the ILC signal presents significant improvements in terms of settling time and overshoot of the pressure signal in the cylinder.
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