Education and demonstration – Vehicle operator instruction or testing – Flight vehicle
Reexamination Certificate
1999-06-17
2001-09-04
Cheng, Joe H. (Department: 3743)
Education and demonstration
Vehicle operator instruction or testing
Flight vehicle
C434S055000, C348S123000, C353S079000
Reexamination Certificate
active
06283758
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a simulator system, and in particular to a simulator system which is suitable for use in a flight simulator.
Flight simulators comprise a viewing station which is occupied by a user of the simulator, the appearance of the viewing station to an occupant being a facsimile of the interior of an aircraft cockpit. The viewing station is mounted on a support frame which is displaceable to simulate in-flight motion. The support frame also supports a visual display assembly arranged to present an image to be viewed on a display surface which is visible from a predetermined eyepoint within the viewing station. Typically, the visual display assembly comprises a back projection screen, a projector positioned to project an image onto the back projection screen, and a concave mirror in which a reflection of the back projection screen is viewed from the predetermined eyepoint through a window defined by the structure of the viewing station. The mirror can be of the order of two meters high and thus defines a relatively large surface area. It is difficult to illuminate the back projection screen with sufficient intensity to provide adequate brightness in the reflection of the back projection screen which is viewed in the mirror.
Flight simulators which are used for simulating take off or landing are used in circumstances in which most of the visually significant image information appears in the lower portion of the view through the viewing station window. Thus it is known to arrange the visual display assembly such that the reflection of the back projection screen occupies only a lower portion of the image viewed through the window, the upper portion being occupied by a “background” display. For some applications however this approach is not acceptable, for example in a simulator for use in in-flight refuelling training. During in-flight refuelling, the aircraft being refuelled must be accurately positioned slightly behind and slightly below a tanker aircraft and as a result the visually significant information occupies upper portions only of the view from the eyepoint through the viewing station windows. Accordingly, in simulators which must be capable of simulating a full refuelling mission including take off, refuelling and landing, it is not possible to maintain an acceptable level of brightness in the significant portions of the viewed scene by arranging the visual display assembly such that the reflection of the back projection screen occupies only a portion of the view from the eyepoint through the viewing station windows. Accordingly in such applications it has been conventional practice to provide a display system with a field of view large enough to satisfy all the requirements, but such an approach requires the use of very large optical components and results in a relatively low brightness low resolution display.
It has been proposed to address the problem outlined above by mounting the viewing station so that it can be displaced relative to the visual display assembly. In this known arrangement, the viewing station is mounted so as to rotate relative to a horizontal axis, rotation of the viewing station adjusting the position of the display surface relative to a viewing window defined by the viewing station. This adjusts the position of the display surface relative to the viewing window when viewed from the predetermined eyepoint, and makes it possible by displacement of the viewing station to appropriately position the visually significant image information relative to the viewing station windows.
Displacement of the viewing station in the known arrangement is difficult to control with sufficient accuracy to avoid the displacement being apparent to an occupant of the viewing station. Firstly, the eyepoint of the viewing station must not move significantly in translation during displacement of the viewing station. Secondly, acceleration of the viewing station relative to the support frame must be miinimised if that acceleration is not to give an occupant of the viewing station false cues. These requirements have proved difficult to achieve with the known arrangement.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved simulator system in which displacement of the viewing station relative to the visual display assembly does not provide an occupant of the viewing station with false cues.
According to the present invention, there is provided a simulator system comprising a visual display assembly arranged to present an image to be viewed on a display surface and a viewing station positioned in front of the display surface such that a person looking from a predetermined eyepoint defined within the viewing station can see the display surface through a viewing window defined by the viewing station, wherein the visual display assembly is mounted in a fixed position on a support frame, and the viewing station is pivotally mounted on the support frame and is connected to an actuator arranged to displace the viewing station relative to the support frame between predetermined first and second positions, the arrangement being such that displacement of the viewing station between the first and second positions causes the viewing station to rotate about the eyepoint, and the actuator being arranged such that the rate of rotation of the viewing station increases with distance from the first and second positions to a maximum when the viewing station is in a third position intermediate the first and second positions.
Preferably, the viewing station is mounted on pivotal links extending from the support frame and defining with the viewing station and the support frame a four bar linkage. The actuator may comprise a constant velocity motor coupled by a pivotal linkage to the viewing station. The pivotal linkage may comprise a link mounted between a pivot mounted on the viewing station and a pivot mounted on an arm extending from a shaft of the motor, the arm being rotatable about a rotation axis of the motor between a first position in which the two pivots are aligned with but on opposite sides of the axis and a second position in which the two pivots are aligned with but on the same side of the axis.
The visual display assembly may comprise a back projection screen, a projector for projecting an image onto the back projection screen, and a concave mirror which defines the display surface. The back projection screen and the mirror are positioned such that a reflection of the back projection screen is visible in the mirror from the eyepoint.
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Cheng Joe H.
Nixon & Vanderhye
Thomson Training & Simulation Limited
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