Flight Motion Simulator Research Articles

Motion Simulation Capabilities of Three-Degree-of-Freedom Flight Simulators

We present the results of a study aimed at determining the simulation realism that might be achieved using reduced-degree-of-freedom flight simulator motion bases. More specifically, the quality of motion produced by two different three-degree-of-freedom platforms was compared to that produced by a conventional six-degree-of-freedom Stewart platform. The three-degree-of-freedom motion bases investigated were a spherical mechanism allowing only rotational motions, as well as a motion base capable of heave, pitch, and roll motions. To compare the different motion bases, three characteristic maneuvers were simulated using a nonlinear model of a Boeing 747. The aircraft motions were then simulated on nine different combinations of virtual motion platforms and motion base drive algorithms. The motion cues (specific forces and angular velocities) produced in this manner were then graphically compared. The analysis revealed that, in most cases, a three-degree-of-freedom simulator is capable of producing motion simulation quality comparable to that produced by a six-degree-of-freedom Stewart platform

Feedback linearization for acceleration control of electrohydraulic actuators

Accurate control of acceleration is important in several fields: prime examples are flight simulator motion and vehicle active suspensions. In both these applications hydraulic actuation is normally found to be most appropriate, despite certain non-linear characteristics. This paper describes a feedback linearization technique for controlling the acceleration of electrohydraulic actuators, compensating for the main non-linear characteristics of the valve and cylinder. Two versions are simulated and compared with conventional linear controllers. The first version requires velocity, acceleration and pressure feedback; the second dispenses with the need for acceleration measurements. Significant performance improvements are achieved over conventional methods.

Pilot evaluations of augmented flight simulator motion

In an earlier paper it was proposed that the turbulence-induced motion of a flight simulator could be augmented without affecting the visual and instrument displays. This may be necessary if the simulator's washout filters severely restrict its motion response to atmospheric turbulence. The present study has implemented the proposed technique on the University of Toronto Institute for Aerospace Studies flight research simulator, and carried out pilot evaluations for both high-altitude and low-altitude operations in the presence of atmospheric turbulence. The results indicate that the technique can successfully increase the simulator's motion response to turbulence in a manner that is acceptable to pilots. It was found that a simple second-order transfer function representation of the aircraft is sufficient within the motion augmentation channel. The resulting motions were judged to add to the realism of the simulation and to compare favorably with other training simulators.

The Digital Control System Realization of a Short Range Surface to Air Missile

This paper presents the digital control system realization of a Short Range Surface to Air Missile(SRSAM). The digital control system consists of on-board computer, control sensors and input/output data interface, whose functions are processing of autopilot algorithm, control gain scheduling, fin command mixing, and data interfacing. Design requirements of the on-board' computer are to execute the autopilot algorithm within 5 msec, to meet the interface protocol with other subsystems, and to minimize the weight and size. In order to verify the performance of the realized digital control system, real time Hardware-In-the-Loop Simulation(HILS) using AD1100/10 computer and Carco Flight Motion Simulator(FMS) is performed.

Augmenting flight simulator motion response to turbulence

When flight simulator motion systems are tuned for acceptable response to pilot control inputs, it is found that their response to turbulence may be unduly attenuated. The motion augmentation technique described in this paper allows the designer to increase the simulator's motion response to turbulence without otherwise altering its flight characteristics. The method employs a second set of flight equations excited only by the turbulence signals. The output from these equations is added to that from the primary simulation flight equations before being fed to the motion system. A sample case is developed showing its successful application to the heave channel of the University of Toronto Institute for Aerospace Studies Flight Research Simulator.

Response of airline pilots to variations in flight simulator motion algorithms

The use of physical motion in flight simulation is still a much debated topic. This paper investigates the more narrow issue of its application in commercial jet transport simulators. We have attempted to quantify the perceptions of airline pilots about the quality of motion possible when a number of different motion-drive algorithms are tested on a simulator employing a state-of-the-art six-degrees-of-freedom motion-base. Four broad categories of algorithms were tested: classical washout, optimal control, coordinated adaptive, and no-motion. It was found that although there was little impact of algorithm type on performance arid control activity, there was a definite effect on how the pilots perceived the simulation environment. Based on these findings, it appears that the coordinated adaptive algorithm is generally preferred by the pilots over the other algorithms tested, there was almost unanimous dislike of the no-motion case.

The Relationship between Flight Simulator Motion and Training Requirements

Flight simulator motion has been demonstrated to affect performance in the simulator, but recent transfer of training studies have failed to demonstrate an effect upon in-flight performance. However, these transfer studies examined the effects of motion in experimental designs that did not permit a dependency relationship to be established between the characteristics of the motion simulated and the training objectives or the performance measured. Another investigator has suggested that motion cues which occur in flight can be dichotomized as maneuver and disturbance cues, i.e., as resulting from pilot control action or from external forces. This paper examines each type cue and relates it analytically to training requirements. The need to establish such relationships in simulator design is emphasized. Future transfer studies should examine specific training objectives that can be expected to be effected by motion.