Ethernet-controlled aircraft door simulation

Ethernet control technology is being used on a new generation of aircraft door trainers to simulate realistic emergency situations during training of flight staff of airlines planning to fly the new double-decker Airbus A380.

The dynamic control of motion is made possible by a high-speed ethernet 'Powerlink' machine network to simulate complex functions and emergency scenarios on commercial aircraft in real-world situations that may be encountered both in the air and on the ground.

The Cabin Emergency Evacuation Trainer (CEET), which is manufactured by EDM, uses an ethernet-compatible machine controller from Baldor Electric Company, with two servo motor axes to control the operating characteristics of the hinge and handle of an aircraft's emergency exit door. The 100 Mbps control network allows EDM to dynamically vary the loading force that each of the two motors apply throughout the door's operational cycle. This gives airline trainers the means to realistically simulate problems that may range from a simple failure of the door's hydraulic automation, to complex scenarios such as obstructions in front of the door or damage to it.

The introduction of drives that are compatible with the real-time ethernet has allowed EDM to create a far more elegant and flexible control system. A single controller dynamically manages the position, speed and torque limits on both servo motor axes, as well as a large array of inputs and outputs that control other simulated aircraft functions such as the cabin lights and indicators.

The engineering development environment for the motion control system was a critical factor for EDM, as simulators are typically application-specific systems that are produced in very small quantities. The EDM development team looked for simple connectivity of the real-time machine and motion controller with a PC that was running graphical aircraft emergency simulation software. The motion and input and output control software is written in Mint, which is Baldor's high level machine and motion control language.

The major functional addition in this iteration of the design process is the ability of the remote controller to dynamically vary each motor's forward and reverse torque limits, based on the angular position of the door and handle. EDM and its users exploit this ability to program sophisticated 'pressure profiles' such as stiff doors and door and handle jams.

"Software development represents one of the largest elements of our product costs," says EDM's systems manager, Alan Nicholson. "The high level nature of the Mint language helps us to minimise the engineering cycles for new simulator designs. With the base software in place, modifying it to emulate different types of aircraft door can be achieved very quickly."

EDM bundles the software tools onto the control PC that is provided with each of the simulators, which offers rapid engineering support to airline customers anywhere in the world in the event of a problem. They can simply log into the system over the internet to access online support and assistance.

The first user of EDM's new generation of simulation technology is a major European airline who has commissioned a cabin trainer for the Airbus A319 aircraft. Since this order, EDM has completed a door trainer for the inaugural purchaser of the new double-decker Airbus A380.

EDM is additionally employing the real-time torque control facility of Baldor's ethernet Powerlink motion control modules to emulate brake pedal action on a vehicle simulator project.

"The speed of the ethernet Powerlink allows EDM to vary torque limits dynamically rather than simply configuring them. This is a control mechanism that is simply not feasible using a traditional analog interface, or a general purpose fieldbus," adds Baldor's David Greensmith. "This new network will allow most machine builders to take a completely fresh look at their control system architecture since our single ethernet controller can handle up to 200 devices on the network simultaneously."