Airships, drones, unmanned aircraft – are these the future workhorses of the air? Andy Pye looks at some futuristic ideas being investigated at present.
Energy pipelines are mainly buried underground. Damage may inadvertently occur during land-clearing, construction, or farming work. The Right Of Way Automated Monitoring (RAM) Project, is looking at innovative technologies to improve and automate pipeline monitoring in the United States and internationally. The ultimate goal of the RAM project is to use aerial surveillance through unmanned aircraft to provide continuous, real-time detection and reporting of threats to pipeline integrity.
The first test flight using a fixed-wing unmanned aircraft to inspect an energy pipeline route – with a piloted chase helicopter following behind to ensure safety beyond the ground observers’ sight line – was completed in March 2015. The flight lasted about 90 minutes and covered about 11 miles over a Colonial Pipeline Company right of way near Fork Union in rural Virginia.
American Aerospace Technologies is a Pennsylvania company that creates Unmanned Aircraft Systems for industry use. It provided and piloted the test aircraft – an RS-16 UAS, which can be equipped with a special sensor package. The RS-16 aircraft has a wingspan of over 4m, an 11kg payload capacity, and is capable of flying more than 12 hours before refuelling. During future flight tests, the aircraft will be equipped with mapping capabilities and a sophisticated sensor package to detect threats to the pipeline.
“Aerial inspection of energy pipelines is federally required and typically performed using manned aircraft flying at low altitudes,” says Chief Executive Officer David Yoel. “If we validate unmanned aircraft technologies, we can reduce risks to pilots and the public, and more efficiently protect the country’s critical infrastructure.”
Ultimately, the Federal Aviation Administration will decide whether unmanned aircraft operations for utility inspections have met safety standards. Organisers say a new round of testing will be underway later this spring.
Meanwhile, the potential of drones for local deliveries has raised major safety concerns. Because drones can run out of power, forcing them to land immediately, they must be able to detect safe landing spots and properly execute landing operations. Furthermore, potential crash situations arise when drones temporarily lose their GPS position information, for instance, when flying close to buildings where GPS signal is lost. In such situations, it is essential that drones can rely on back-up systems and regain stable flight.
Researchers at the University of Zurich have unveiled new technology enabling drones to recover stable flight from any position and land autonomously in failure situations. It should even be possible to launch drones by simply tossing them into the air like a baseball or recover stable flight after a system failure.
“Our new technology allows safe operation of drones beyond the operator’s line of sight, which is crucial for commercial use of drones, such as parcel delivery,” says Prof. Davide Scaramuzza, co-inventor and Director of the Robotics and Perception Group at the University of Zurich.
The UZH drones are equipped with a single camera and acceleration sensors. Their orientation system is designed to emulate the human visual system and sense of balance. As soon as a failure situation is detected, computer-vision software analyses the images to identify distinctive landmarks in the environment and restore balance. All image processing and control runs on a smartphone processor on-board the drone. This renders the drone safe and able to fulfil its mission without any communication or interaction with the operator. The same software builds a 3D model of the environment, which is used to group the terrain beneath the drone into “risky” and “safe” landing sites. If an emergency landing is required due to low battery or system failure, the drone will automatically detect and land on a flat, safe location without any human intervention.
In a related approach, Mexican researcher José Martínez has proposed an innovative method to estimate the position and orientation of the vehicle, allowing it to recognize its environment, hence to replace the GPS location system for low-cost sensors such as accelerometers, gyroscopes and camcorders. The work was carried out during his post-doc at the University of Bristol, in collaboration with the British company Blue Bear, which provided the drones and control algorithms.
Airships – the future of aviation?
Can airships represent the future of aviation? It is forecast that by 2020 the number of aircraft passengers will reach 400 million. The movement of freight by air is expected to increase by more than 340% over the next 20 years. During the same period, congestion at many of the UK’s airports will squeeze out cargo operations for economic and environmental reasons. Consequently, if the market demand for air freight is to be met, either there will have to be significant investment in new airport infrastructure or alternative transport forms need to be considered.
A Pan-European team research team, including researchers from the University of Lincoln, think so. They have now completed a three year investigation into stratospheric passenger airships which puts forward the idea that airships may be the ‘green’ answer to a future sustainable air transport network. The project was first reported on in 2012.
The Multibody Advanced Airship for Transport (MAAT) project aims to position airships as future air transportation that is safe, efficient, cheap and environmentally friendly. The MAAT project, made up of eight nations and led by the Universita di Modena e Reggio Emilia in Italy, envisages the design of a cruiser which can travel across the globe on a set route. Smaller feeder ships carrying people and goods would then be able to dock onto the cruiser while it is still moving.
MAAT could present lower costs of transportation than any other current transport system, as it does not require fuelling and its vertical take-offs would reduce delivery times and free-up runway space across the globe. Also, silent landing and take-off operations would reduce the environmental impact of air travel, allowing 24-hour operation within busy cities.
“The design of an all-electric airship is demanding, as increasing efficiency invariably increases weight which impacts the size, which impacts drag and so on. The greatest challenge has been managing the electrical systems efficiency and weight, thus preventing the spiral – this will be a continuing challenge,” says Tim Smith, Senior Research Fellow at the Lincoln School of Engineering.
The primary proposed energy source for the MAAT is through harvesting sunlight from photovoltaic arrays mounted on the upper airship surface to provide sufficient electric power during the day to operate the airship’s systems, and provide life support, propulsion and control, while also producing sufficient excess energy that can be stored to facilitate continuous MAAT operation at night.
The University of Lincoln team’s research has focused on how to make the most efficient use of energy generated by the photovoltaic cells on the airships and its subsequent use in the electrical power systems, energy storage and the propulsive power requirements. It is hoped that with the introduction of innovative propulsion systems that the limitations of traditional propellers at high altitudes will be overcome, resulting in an efficient propulsive system.
Various energy storage systems and design options can be adopted for airships, taking account of the needs of day/night operation. A recent focus of the project is energy harvesting, distribution and storage, utilising a modular approach to simplify future scaling and system integrity under failure conditions.