EUCASS

Hermitage, St Petersburg

I'm just back from attending the European Conference on Aerospace Sciences (EUCASS) in St Petersburg.  Visiting Russia and the imposing city of St Petersburg was a great experience, but I'll try to keep to the technical side in this post.

There was much coverage of launchers, not really my field but interesting anyway.  A concept caught my eye for using a GlobalHawk UAV to lift a launcher rocket for small satellites, similar to the Pegasus system - only got a brief glimpse though.

My student Colin Greatwood presented his work on collision alerting for helicopters, while colleague Massimiliano Saponara from Thales Alenia Space Italy presented results from our ORCSAT study with ESA.  It was interesting as well to see Princeton Satellite Systems proposing something MPC-like for rendezvous in their Space Rapid Transit system.

Finally, an idea: has anyone ever tried MPC for aircraft fuel system management?

GENSPACE: air traffic control for beginners

Photo courtesy EUROCONTROL

I'm just back from two days at the EUROCONTROL Experimental Centre just outside Paris, participating in the GENSPACE course for air traffic control experience.  Aimed at researchers and others in ATC-related activities, this is a chance to gain a bit of first-hand experience in ATC through presentations and simulations.  The EEC has extensive facilities including 44 controller consoles (see photo), 35 pilot consoles, all networked together for simulations of up to 350 aircraft.  The GENSPACE experience includes sessions controlling en-route, TMA and approach sectors, guided by experienced instructors.  I certainly learnt a lot.  It was interesting to see the different conflict resolution strategies in different sector types.  Even at our easy-paced simulations, with a group of about 16 of us covering an area over Vienna, it was pretty draining to manage an hour of traffic.  The experience will prove invaluable for our two forthcoming ATC projects with SESAR.  Thanks to EUROCONTROL and the HALA research network for the opportunity.

New journal paper: airport taxi optimization

UPDATE: now in print

Clare, G. L.; Richards, A. G.; , "Optimization of Taxiway Routing and Runway Scheduling," Intelligent Transportation Systems, IEEE Transactions on , vol.12, no.4, pp.1000-1013, Dec. 2011, doi: 10.1109/TITS.2011.2131650

Abstract: This paper describes a mixed-integer linear programming optimization method for the coupled problems of airport taxiway routing and runway scheduling. The receding-horizon formulation and the use of iteration in the avoidance constraints allows the scalability of the baseline algorithm presented, with examples based on Heathrow Airport, London, U.K., which contains up to 240 aircraft. The results show that average taxi times can be reduced by half, compared with the first-come–first-served approach. The main advantage is shown with the departure aircraft flow. Comparative testing demonstrates that iteration reduces the computational demand of the required separation constraints while introducing no loss in performance.

ORCSAT, or How to Catch a Basketball in Mars Orbit

Recently we have been working on a European Space Agency (ESA) project called "On-line Reconfiguration Control System and Avionics Technologies" or "ORCSAT".  Our role, in collaboration with the control group at the University of Cambridge, has been to design a Model Predictive Control (MPC) system for spacecraft rendezvous.  The scenario is the rendezvous in Mars orbit with a sample canister, launched from the Martian surface and to be transported back to Earth for analysis.  Loosely speaking, we're trying to catch a basketball from 50km away...

MPC works by using a trajectory optimizer to design the manoeuvres in real time to use minimum propellant.  The challenge is to design the optimizer to balance complexity with speed.  Too detailed, and the optimization takes too long to solve: too approximate, and the manoeuvre doesn't go where predicted and you burn too much fuel.  The figure on the right shows an example of the resulting trajectory.  Bristol researcher Paul Trodden developed the far-term MPC that gets us to a similar orbit to the target and close enough to track it.  Then Cambridge researcher Ed Hartley's controllers take over to "hop" closer to the target and finally intercept it.  Initial results suggest that MPC is very efficient, reducing the fuel needed to accomplish the rendezvous.

Our collaborator Alberto Bemporad from the University of Trento developed MPC software to enable all these controllers to share the same optimizer.  Also in the consortium are GMV in Spain, who provided a rendezvous simulator, Reliacon of the Netherlands, who are verifying the controllers, and Thales Alenia Space Italy (TAS-I), who lead the project.  TAS-I and GMV are now implementing and testing the MPCs as the project continues.

Publications update

I've updated my publications page to include our most recent conference and journal papers.

Farnborough Air Show

Just back from exhibiting at Futures Day at the Farnborough Air Show.  Among the people we met, it was encouraging to bump into so many Bristol graduates in the aerospace business.  Now, watch this space as we work on our autonomous mini-Blades display team...

Congratulations Gillian

Gillian Clare (nee Keith) has passed her PhD viva with only minor corrections to be done.  Gillian's work on aircraft taxi optimization, supported by Airbus, identified a possible saving of total delay time of 56% at London's Heathrow Airport.  Gillian now moves on to work at BAE Systems in Filton.