Control loading system
Encyclopedia
A Control Loading System (CLS, also known as Electric Control Loading), is used to provide pilots with realistic flight control forces in a flight simulator
or training device. These are used in both commercial and military training applications.
, also known as the Blue Box. This was developed in the 1920’s and used pumps, valves and bellows to provide the flight control forces. The next development in control loading systems was the use of hydraulic actuators to provide the forces required on the flight controls. These were utilized for around 20 years in the simulator industry until the development of electric actuators.
The control loading system must take in inputs from the simulator and pilot and provide outputs for the pilot and simulator. Inputs are application of force and aircraft states and outputs are flight control position and forces.
An aircraft with reversible controls needs to have all of the complex components modeled within the control loading system. These include cables, rods, aero forces from the control surface, centering springs and trim actuators. As the control system gets more complicated they have to simulate effects such as bob-weights and feel units. Fly-by-wire
systems are disconnected from the control surfaces and so do not need the complex features but add other functionality which is simulated.
The high fidelity architecture has centralized control, individual analog signals to the control module, a brushless DC motor with low gear ratio and linkages to the pilot controls.
The modular designs have localized control and digital reporting over a field bus to the central control module. The control loading systems are designed to allow situating the actuators closer to the pilot. This is necessary for mission training systems that can be easily deployed and moved around the world.
Control Loading Systems are similar in design to active sidesticks. These provide cues to pilots during the flight via actuation systems. Some examples of active sidesticks used in aircraft are for the F-35 Lightning II
and the T-50 Golden Eagle
jet trainer developed by KAI in partnership with Lockheed Martin Corporation.
regulations in North America and EASA (formerly JAA) in Europe. The FAA documents are AC 120-40B for airplane simulator qualification, Advisory circular 120-45A for Airplane Flight Training Device Qualification and AC 120-63 for helicopter Simulator Qualification. The EASA regulations are similar to the FAR’s.
Between 2006 and 2008 the International Working Group of the RAeS’s Flight Simulation Group met on several occasions to redefine the standards applicable to flight simulation. This resulted in the release of a draft standards document to ICAO. This will be released by ICAO in 2009 and at this time the FAA and EASA should incorporate this into the regulations. The changes behind the standards will define different levels of simulator training devices which define what training requirements can be trained on with particular levels of simulators.
Flight simulator
A flight simulator is a device that artificially re-creates aircraft flight and various aspects of the flight environment. This includes the equations that govern how aircraft fly, how they react to applications of their controls and other aircraft systems, and how they react to the external...
or training device. These are used in both commercial and military training applications.
History
The history of control loading systems starts with the history of flight simulation. The first flight simulator was the Link TrainerLink Trainer
The term Link Trainer, also known as the "Blue box" and "Pilot Trainer" is commonly used to refer to a series of flight simulators produced between the early 1930s and early 1950s by Ed Link, based on technology he pioneered in 1929 at his family's business in Binghamton, New York...
, also known as the Blue Box. This was developed in the 1920’s and used pumps, valves and bellows to provide the flight control forces. The next development in control loading systems was the use of hydraulic actuators to provide the forces required on the flight controls. These were utilized for around 20 years in the simulator industry until the development of electric actuators.
Design and Technology
The main concept is to provide forces to the pilot using an actuator (hydraulic or electric). The approach used in high fidelity applications is to connect this actuator via a linkage to the pilot controls. The actuator is then controlled with a servo controller to control the torque or current of the motor. An outer-loop control then controls the torque provided to the pilot using a control loop around a force sensor.The control loading system must take in inputs from the simulator and pilot and provide outputs for the pilot and simulator. Inputs are application of force and aircraft states and outputs are flight control position and forces.
An aircraft with reversible controls needs to have all of the complex components modeled within the control loading system. These include cables, rods, aero forces from the control surface, centering springs and trim actuators. As the control system gets more complicated they have to simulate effects such as bob-weights and feel units. Fly-by-wire
Fly-by-wire
Fly-by-wire is a system that replaces the conventional manual flight controls of an aircraft with an electronic interface. The movements of flight controls are converted to electronic signals transmitted by wires , and flight control computers determine how to move the actuators at each control...
systems are disconnected from the control surfaces and so do not need the complex features but add other functionality which is simulated.
The high fidelity architecture has centralized control, individual analog signals to the control module, a brushless DC motor with low gear ratio and linkages to the pilot controls.
The modular designs have localized control and digital reporting over a field bus to the central control module. The control loading systems are designed to allow situating the actuators closer to the pilot. This is necessary for mission training systems that can be easily deployed and moved around the world.
Control Loading Systems are similar in design to active sidesticks. These provide cues to pilots during the flight via actuation systems. Some examples of active sidesticks used in aircraft are for the F-35 Lightning II
F-35 Lightning II
The Lockheed Martin F-35 Lightning II is a family of single-seat, single-engine, fifth generation multirole fighters under development to perform ground attack, reconnaissance, and air defense missions with stealth capability...
and the T-50 Golden Eagle
T-50 Golden Eagle
The T-50 Golden Eagle is a family of South Korean supersonic advanced trainers and multirole fighters, developed by Korea Aerospace Industries beginning in the late 1990s. The T-50 is South Korea's first indigenous supersonic aircraft and one of the world's few supersonic trainers...
jet trainer developed by KAI in partnership with Lockheed Martin Corporation.
Standards and Regulations
The regulations governing control loading systems for civil simulators are the Federal Aviation AdministrationFederal Aviation Administration
The Federal Aviation Administration is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of civil aviation in the U.S...
regulations in North America and EASA (formerly JAA) in Europe. The FAA documents are AC 120-40B for airplane simulator qualification, Advisory circular 120-45A for Airplane Flight Training Device Qualification and AC 120-63 for helicopter Simulator Qualification. The EASA regulations are similar to the FAR’s.
Between 2006 and 2008 the International Working Group of the RAeS’s Flight Simulation Group met on several occasions to redefine the standards applicable to flight simulation. This resulted in the release of a draft standards document to ICAO. This will be released by ICAO in 2009 and at this time the FAA and EASA should incorporate this into the regulations. The changes behind the standards will define different levels of simulator training devices which define what training requirements can be trained on with particular levels of simulators.