Energy is a vital element for human life, and if modern societies are to be sustained, then obtaining a secure, sufficient, and accessible energy supply is fundamental. The demand for the provision of energy is rapidly increasing throughout the world and this trend is likely to continue in the future. The growing recognition that global warming exists has led more governments, research centers, and corporations to commit resources to the advancement of renewable energy technologies.
Renewable energy generation could, in addition to providing a means to substantially reduce CO2 emissions, help reduce national dependencies on imported energy, thus increasing energy security and diminishing domestic supplies of fossil fuels. One challenge as regards energy is the ability to move to a new low carbon economy in which energy demands can be met while the levels of CO2 emitted are reduced. In order to meet this challenge, it will be necessary to exploit other forms of renewable energy that are currently less developed but which have a high potential, such as marine renewable energy. This had led to an incipient interest in the successful development of these technologies and in bringing them onto the market.
The sea is a huge collector, accumulator, and transformer of clean and inexhaustible energy and is virtually unexploited, despite covering more than 70% of the Earth’s surface. Marine currents are, together with waves, the most promising sources of marine renewable energies. Some of the opportunities and benefits that could be achieved with the exploitation of wave and tidal energy-recovering systems include energy independence, decarbonization, or the creation of jobs. The energy that could be extracted from sea waves and currents is estimated as being more than 8,000 TWh/year.
In spite of the opportunities that these marine renewable energies could provide, there are still some challenges that must be met if an awareness of marine technologies is to be promoted and their current potential increased. The difficulties related to this medium have led to the conception, design, and operation of devices with exceptional features, such as stability, redundancy, seakeeping, or survival in hostile conditions. Meeting these challenges is essential if governments, industry, maritime and oceanic services, research institutions, and universities are to obtain a unified and coordinated approach to achieve robust, feasible, and cost-effective marine technologies. Obtaining these will help the acceleration and sustainability of marine systems. In this respect, the development of new and innovative solutions in robotics and control engineering systems applied to wave and tidal energy-recovering systems has received a great deal of attention in the last years from a considerable number of researchers and from the industrial community.
The objective of this special issue is to show the latest research achievements, findings, and ideas in the fields of robotics and control engineering as regards wave and tidal energy-recovering systems. The topics dealt with in this special issue are the following:(i)Sensor systems: sensors and sensor networks, intelligent sensors, sensor uncertainty for fault tolerant control, and distributed and multimodality sensor network for control and automation, to name but a few.(ii)Control: adaptive control, robust control, active disturbance rejection control, identification and estimation, delay systems, precision motion control, and so forth.(iii)Mathematical modeling: modeling, identification, and simulation of wave and tidal energy-recovering systems.(iv)Robotics: modeling and identification, mobile robotics, mobile sensor networks, perception systems, visual servoing, robot sensing and data fusion, and autonomous and remotely operated (surface and underwater) systems.(v)Industrial informatics: embedded systems for monitoring and controlling wave and tidal energy-recovering systems.
Acknowledgments
We would like to thank all the authors for their excellent contributions and also the reviewers for their valuable help.
Rafael Morales
José A. Somolinos
Carlos E. Ugalde-Loo
José Gaspar