#Redundant flight control system full#

The proposed system would serve as a “back-up” to the primary flight computer in the case of an in-flight loss of communications or control. Thus, they become very hands-on.The Redundant Flight Computer (RFC) project focuses on enhancing the reliability and safety of small Unmanned Aircraft Systems (sUAS) by creating a redundant flight control system. When in alternate and direct law, most fly-by-wire aircraft become very sensitive in all control axes. There is no refining of pilot input data. When in direct law, the computers just act as a medium to direct the control surfaces as the pilot demands. In this situation, the loss of these data may prevent the flight control computers from making the required calculations for normal or alternate law. An example can be the loss of inertial and air data information. When there are multiple failures, the aircraft reverts to direct law. With limited control surfaces, the flight control computer demands of normal law might not work on the aircraft. This can occur, for instance, when there is a major hydraulic failure that deactivates a number of flight control surfaces. The alternate law is the first level of control degradation. The alternate and direct law are degraded control laws that become active when aircraft system failures start to occur. This load is then sent to the flight control computers, which activate the control surfaces to meet the load factor demand. As the pilot moves his or her controls back and forward, the movement is converted to a g-load. In a typical fly-by-wire aircraft, the control for pitch is a load factor demand. On the other hand, the alternate and direct laws are reconfiguration laws that become active when system failures exist to the point where the computers can no longer compute accurate data for the control surface actuators.

#Redundant flight control system full#

When in normal law, the flight control computers work at their full capacity. The normal law is active when no system failures exist. The naming convention of these laws varies from manufacturer to manufacturer, but they work similarly. In most fly-by-wire control systems, there are three control laws. Hence, the flight control computers need this data before commanding the spoilers up.Īs discussed earlier, the control laws are what govern how the flight control computers command the flight control actuators. For instance, the ground spoilers on the wings can only come up when the gear oleos are compressed. The latter is used to determine if the aircraft is airborne or on the ground. Landing gear control system: This system feeds the flight control computers information about the position of the landing gear and whether the oleos are compressed or extended.To determine that the aircraft is coming into land, the flight control computers use the aircraft height data from the radio altimeters. For instance, when coming in for a landing, the control law might have to be modified to allow the pilot to have better control of the aircraft. Radio altimeters: In many fly-by-wire aircraft, the flight control laws require to be tweaked at different phases of the flight.These data are highly important for flight control computers. Accelerometers measure the aircraft's vertical and lateral acceleration, while the gyrometers measure the roll rate, pitch rate, and yaw rate. Accelerometers and gyrometers: The accelerometers and gyrometers are placed at various points on the aircraft.These data include calibrated airspeed, angle of attack, altitude, etc. The air data information comes from the Air Data Computers (ADC). Some of the IR data includes aircraft heading, roll, pitch, yaw, etc. Inertial and air data: The inertial data comes from the Inertial Reference System (IRS).Pilot inputs: The pilot inputs are the most important set of data the flight control computers need, as it is this that determines how the aircraft is to be maneuvered.The following is a list of data that is sent to the flight control computers: To make the computations easier and more accurate, flight control computers are fed a lot of information from aircraft systems.