Travelling lighter

Lighter, more efficient aircraft could be built thanks to a one-year EPSRC-funded research project to develop an electronic system that reduces the use of cables.

A team of researchers at the University of Sussex is developing the framework for two electronic systems - a generic avionics system that will reduce the number of cables used to connect sensors in an aircraft, and a standard health and usage monitoring system (HUMS) that will provide constant monitoring of an aircraft's platform.

The new electronics architecture will be designed to help the aerospace industry achieve a green objective set by the Advisory Council for Aeronautics Research in Europe (ACARE), to decrease emissions by 50 per cent by 2020.

'Our ultimate goal is to reduce emissions as much as possible by operating the aircraft more efficiently by trying to reduce the lift, basically the weight, of an aircraft,' said Dr Elias Stipidis, principal investigator on the project.

'If you consider the number of sensors and actuators, and the cabling that is required, it is going to be very heavy if you have point-to-point connections. Connecting all the sensors and actuators over a network reduces the need for kilometres and kilometres of cabling.'

The innovative architecture would control sub-systems, such as flight control, cabin pressure or weather monitoring, and use the information to direct the aircraft to fly in the most efficient manner.

According to Stipidis, the electronic system, which he refers to as the spinal cord of an airborne vehicle, will also be able to adapt an aircraft to external conditions, such as weather.

'We will also use the configuration of the aircraft to adapt to environmental conditions,' he said. 'For example, increasing the efficiency of tail wings by doing some computing calculations and using the sensors around the aircraft to calculate the most efficient speed, direction or height for an aircraft to travel at, depending on the weather conditions.'

Stipidis and his team at Sussex, which includes Dr Periklis Charchalakis and Dr Falah Ali, will also develop sub-system architecture for a generic version of HUMS, which will constantly monitor the status of critical aircraft parts that are connected to sensors, and issue alerts to defective, or potentially problematic, areas for maintenance.

The engineers hope to produce generic frameworks for the systems that could be applied to all aircraft, and scaled up or down depending on requirements.

'Our expertise is in electronic architecture, and because we do a lot of work for the Ministry of Defence, the government wants us to use our expertise in this area to further the knowledge of avionics,' said Stipidis.

He explained that multiple nodes, or electronic computing systems, have to undergo a vigorous certification process before they can be installed on an aircraft because of the high safety standards required. It therefore makes sense to use HUMS to constantly monitor and maintain them, rather than having to replace them when a system failure occurs. This would remove the risk, and potentially disastrous consequences, of an aircraft's system failing during flight.

Versions of HUMS developed so far use electronic systems similar to those that collect data. However, the Sussex team proposes to develop a HUMS network architecture that is separate from the data network on an aircraft. On a fly-by-wire aircraft, which is controlled by an electronic and digital flight-control system, the data network defines how the wings should be set for different operations, such as landing.

'What we're proposing to do is look at a separate, modular HUMS architecture to reduce the amount of data on one network,' said Stipidis. 'By separating the diagnostic HUMS data from the general data network, the overall complexity of the system is reduced, which makes it easier to certify in the future.

'At the same time, you would be able to put HUMS into a mode that could configure the electronic aircraft system without affecting the data system.'

As a specialist in the provision of TTP (time-triggered protocol), a platform technology into which modular computing systems can be embedded, Vienna-based technology company TTTech will provide the equipment to test the electronic architecture.

'TTP provides redundancy management and system health monitoring services that simplify the design of complex system architectures and enable HUMS to be integrated into a control system,' said Dr Mirko Jakovljevic of TTTech's marketing aerospace division.

He added: 'This can directly influence the economics of system design, integration, system availability and reliability, as well as the costs of maintenance.'