Abstract:
Touch or proximity sensors are integrated into control devices such as knobs, dials or wheels incorporated in a user control panel. A control output processor detects whether any of the sensors are outputting signals indicating that a control device is being touched (or nearly touched) by a user. The control output processor causes an associated display area to be highlighted or otherwise modified on a display screen to indicate to the user which control device is being touched. This feature allows for “no-look” interaction with control panels, and keeps the user&#39;s eyes focused on the relevant displays where the control devices produce effects. This allows users to preview and verify that the correct control device is being manipulated prior to taking any (potentially erroneous) control actions.

Description:
BACKGROUND 
       [0001]    This disclosure generally relates to a user interface for enabling a user to control a mode of a machine. In particular, this disclosure relates to hardware control devices on a flight deck of an aircraft. 
         [0002]    Modern jet transports are equipped with a cockpit mode control panel that interfaces with a flight management system to control the selection and engagement of automatic flight control modes of operation. These automatic flight control modes of operation include, for example, flight level change (FLCH), vertical navigation (VNAV) and lateral navigation (LNAV). The FLCH mode can automatically manage thrust and speed to climb or descend from one altitude to another. The VNAV mode can provide automatic optimized profile control from initial climb through final approach, including adherence to terminal area procedure speed and altitude constraints. The LNAV mode can provide steering to a preprogrammed route including selected terminal area procedures. 
         [0003]    The pilot chooses the available modes that will best accomplish the desired vertical flight profile and lateral routing. In most instances, the pilot plans the flight in advance, both laterally and vertically, and preprograms the LNAV and VNAV modes so that the desired flight path will be followed. While preprogrammed flights are advantageous because they reduce the pilot&#39;s burden, particularly during takeoff and landing, in practice, rarely can flights be flown as preplanned. For example, rerouting and clearance instructions may be received from air traffic control (ATC) during the flight. These instructions force the pilot to depart from the vertical flight profile and/or the lateral route that was originally planned. In some instances, rerouting and reclearance come far enough in advance to allow the pilot to reprogram the route or profile instructions stored in the memory of an auto flight computer so that the flight management system can remain in the LNAV and VNAV flight control modes. On other occasions, pilots are forced to manually intervene in order to depart from LNAV and VNAV preprogrammed flight paths and comply with ATC instructions in a timely manner. 
         [0004]    Intervention-capable flight management systems (FMS) have been developed which allow a pilot to intervene in the operation of the preprogrammed auto flight computer of a flight management system and change the speed and/or flight path of an aircraft in response to ATC instructions. One such system is disclosed in U.S. Pat. No. 4,811,230, and entitled “Intervention Flight Management System.” The intervention FMS disclosed in that patent includes a mode control panel via which the pilot interfaces with an FMS program. The FMS program includes several modules that override the preprogrammed instructions stored in the memory of the auto flight computer when the modules are engaged. In this manner, the FMS allows the pilot to manually intervene and control the auto flight computer and, thus, the aircraft in response to, for example, ATC instructions to change heading, altitude, airspeed or vertical speed. The FMS automatically returns to fully optimized flight along the preprogrammed profile when the intervention is cancelled. 
         [0005]    An FMS control panel consists of a multitude of control devices for enabling a pilot to interact with airplane systems and displays. Often these control devices produce a corresponding change to an associated display. For example, turning a knob in one location can change a displayed value in another location. However, some control devices are typically used without looking directly at the controls. To avoid confusion, similarly shaped control devices can be discriminated from each other spatially and sometimes with unique textures. However, operation of the hardware controls on the flight deck is still susceptible to confusion because these control devices do not completely prevent the pilot from reaching for and activating the wrong control device. Furthermore, pilots sometimes only detect the error after the incorrect control device has been used, which produces an unexpected change in the associated display (and sometimes unwanted aircraft performance). 
         [0006]    There is a need for an improved system and method that can be used to help avoid such control errors. 
       SUMMARY 
       [0007]    An improved system and method for enabling a control panel user, while looking at an associated display screen rather than the control panel, to verify that the user is touching a correct control device on that control panel. In accordance with some embodiments, touch or proximity sensors are integrated into control devices such as knobs, dials, levers, or wheels incorporated in a user control panel. A control output processor detects whether any of these sensors are outputting signals indicating that a control device is being touched (or nearly touched) by a user. The control output processor causes an associated display area to be highlighted or otherwise modified on a display screen to visually indicate to the user which control device is being touched. (An “associated” display area is a region on a display screen that will be affected by an action performed by the user when manipulating the touched control device.) This feature allows for “no-look” interaction with control panels, and keeps the user&#39;s eyes focused on the relevant displays where the control devices produce effects. This allows users to preview and verify that the correct control device is being manipulated prior to taking any (potentially erroneous) control actions and without the user looking at the control panel. 
         [0008]    The benefits of the above-described system and method include at least the following: 
         [0009]    (1) The highlighting (or other visual change) offers a preview of where the control inputs will produce changes on the display device. This allows the user to find the correct control while keeping his/her visual attention directed at a non-collocated display device, without necessarily having to refocus attention to find the correct control device. 
         [0010]    (2) Because the user can direct his/her attention toward a display device rather then the control device he/she is manipulating, the control panel can be simplified and less feedback/data on the panel itself (such as numerical windows or other displays) is required. Information (e.g., control settings and values) can be consolidated on the main display rather than being redundantly shown on the control panel. 
         [0011]    (3) The foregoing technical feature aids with error prevention by confirming that the correct control device is being touched prior to taking action by manipulating the control device. 
         [0012]    In accordance with one aspect, an interface system for enabling a user to control a mode of a flight vehicle is provided. The system comprises: a control panel comprising first and second settable control devices configured to output first and second setting signals representing respective current settings of the first and second settable control devices; a first sensor configured to output a user proximity signal while the first settable control device is being touched by a user; a second sensor configured to output a user proximity signal while the second settable control device is being touched by a user; a display system comprising a display screen that is not part of or collocated with the control panel; and a computer system coupled to receive the first and second setting signals from the first and second settable control devices and receive any user proximity signal output by the first or second sensor and further coupled to send display control signals to the display system. The computer system is programmed to output display control signals that control the display system to display pixel data indicating the current settings of the first and second settable control devices and whether or not the first or second settable control device is currently being touched by the user. In accordance with one embodiment, the computer system is programmed to produce a first display control signal that controls the display system to display pixel data indicating the current setting of the first settable control device in a first area of the display screen, a second display control signal that controls the display system to display pixel data indicating the current setting of the second settable control device in a second area of the display screen which does not overlap the first area of the display screen, and a third display control signal that changes pixel data displayed in the first area of the display screen in response to the presence of a user proximity signal from the first sensor for a time interval having a duration greater than a first threshold value. 
         [0013]    In accordance with another aspect, an interface system for enabling a user to control a mode of a machine comprises: a control panel comprising first and second settable control devices configured to output first and second setting signals representing respective settings of the first and second settable control devices; a first sensor configured to output a user proximity signal while the first settable control device is being touched by a user; a second sensor configured to output a user proximity signal while the second settable control device is being touched by a user; a display system that is not part of or collocated with the control panel; and a computer system coupled to receive the first and second setting signals from the first and second settable control devices and receive any user proximity signal output by the first or second sensor and further coupled to send display control signals to the display system. The computer system is programmed to output display control signals that control the display system to display pixel data indicating the settings of the first and second settable control devices and pixel data indicating that the first or second settable control device is being touched by the user. The foregoing system may further comprise an auto flight computer coupled to receive the first and second setting signals from the computer system, and a flight control system comprising hardware components which are operated in a mode that is responsive to the first and second settings. A further aspect is an intervention flight management system comprising the system as described in this paragraph. 
         [0014]    In accordance with a further aspect, a method for producing a visual indication that a user is touching a control device on a control panel is provided. The method comprises the following steps: producing an electrical user proximity signal whenever the user is currently touching the control device and not producing the electrical user proximity signal whenever the user is not touching the control device; producing a first electrical display control signal in response to the absence of an electrical user proximity signal for a time interval having a duration greater than a first threshold value; displaying a first set of pixel data in an area on a display screen that is associated with the control device, but is not part of or collocated with the control panel, while the first electrical display control signal is being produced, the first set of pixel data comprising a first subset of pixel data indicating a current setting of the control device; producing a second electrical display control signal in response to the presence of an electrical user proximity signal for a time interval having a duration greater than a second threshold value; and displaying a second set of pixel data in the area on the display screen while the second electrical display control signal is being produced, the second set of pixel data comprising a first subset of pixel data indicating the current setting of the control device, wherein the second set of pixel data is not identical to said first set of pixel data. 
         [0015]    Other aspects of the system and method are disclosed and claimed below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a block diagram illustrating a flight management system (FMS) in accordance with one embodiment. 
           [0017]      FIG. 2  is a diagram showing a front view of an FMS control panel incorporated in the system depicted in  FIG. 1 . 
           [0018]      FIG. 3  is a diagram showing a front view of a primary flight display incorporated in the system depicted in  FIG. 1 . 
           [0019]      FIG. 4  is a diagram showing a front view of a mini-map of a primary flight display in accordance with the embodiment depicted in  FIG. 3 . 
           [0020]      FIG. 5  is a flowchart showing steps of a method for determining the state of a primary flight display as a function of which control device has been touched or nearly touched by the pilot. 
       
    
    
       [0021]    Reference will hereinafter be made to the drawings in which similar elements in different drawings bear the same reference numerals. 
       DETAILED DESCRIPTION 
       [0022]    Modern aircraft may employ a flight management system (FMS).  FIG. 1  is a block diagram illustrating one example of an FMS formed in accordance with one specific application of the concept disclosed herein. The FMS of the embodiment of  FIG. 1  comprises an auto flight computer  10  that has been programmed to control the state of various hardware components of a flight control system  12 . A conventional fixed-wing aircraft flight control system consists of flight control surfaces (e.g., ailerons, elevators and rudder), connecting linkages, and the necessary operating mechanisms to control an aircraft&#39;s direction in flight. Aircraft engine controls are also considered as flight controls as they change speed. These operating mechanism components include, for example, roll, pitch and autothrottle control actuators (not shown). These control actuators may comprise any suitable actuators for controlling the roll, pitch and autothrottle of an aircraft, such as servos and fly-by-wire actuators. 
         [0023]    The embodiment shown in  FIG. 1  further comprises a mode control panel  14  which transmits commands to the auto flight computer  10  via a control output processor  16 . The electrical signals representing these commands are generated in response to the pilot contacting and manipulating various control devices  18 , such as knobs, wheels, levers and buttons, which are incorporated in the control panel  14 . In another embodiment, the auto flight computer  10  periodically interrogates the status of the control devices  18  and uses the resultant information to engage, disengage and control paths through the modules of an FMS program stored in the auto flight computer  10 , along with programs that create other automatic flight control modes, such as LNAV and VNAV flight control modes. 
         [0024]    The mode control panel  14  also receives current parameter value signals (not shown) from the auto flight computer  10 . The auto flight computer  10  also sends current parameter value signals to a display system  22  for display thereby. The display system  22  comprises a primary flight display that is configured to display symbology, graphical elements, icons, coloring, shading, highlighting, etc. in order to visually communicate air data and basic flight information. 
         [0025]    In accordance with the embodiment shown in  FIG. 1 , based on preprogrammed instructions and/or commands, the auto flight computer  10  produces guidance commands, which are applied to the actuators of the flight control system  12 . In accordance with these guidance commands, command signals are applied to the actuators by respective actuator amplifiers (not shown), such as a roll actuator amplifier, a pitch actuator amplifier and a thrust actuator amplifier. The actuators produce feedback actuator position signals (not shown) which are sent back to the respective actuator amplifiers. As a result, actuator loop control systems are formed between the roll actuator amplifier and the roll actuator, between the pitch actuator amplifier and the pitch actuator, and between the thrust actuator amplifier and the autothrottle actuator. 
         [0026]    The guidance commands produced by the auto flight computer  10  control the orientation and speed of the aircraft in a well-known manner. In this regard, it should be understood that  FIG. 1  is a simplified block version of a sophisticated system for controlling the orientation and speed of an aircraft. As explained in more detail below, the disclosed embodiments are directed to a FMS in which the state of the primary flight display is determined in response to and as a function of pilot manipulation of the control devices  18  incorporated in the mode control panel  14 . Accordingly, the well-known details of how the auto flight computer  10  controls the orientation and speed of an aircraft using the flight control system  12  are not disclosed herein. 
         [0027]    The mode control panel  14  allows a user, such as a pilot of the aircraft, to interface with the FMS. The mode control panel  14  may include a number of different sections, such as a direction section, an altitude section, a speed section and a vertical path section, for allowing the pilot to control various functions of the FMS. (One example of such a mode control panel will be described later with reference to  FIG. 2 .) Each section comprises one or more control devices  18 , as previously described. In accordance various embodiments disclosed herein, independent of the respective settings of the control devices, sensing means are providing for detecting when the control devices are touched (e.g., by a pilot placing a finger in contact with a control device) or nearly touched. 
         [0028]    In accordance with one embodiment, the mode control panel  14  further comprises a multiplicity of touch or proximity sensors  20 , each touch sensor corresponding to a respective control device having an associated graphical element to be displayed on the primary flight display (described in detail below). In these embodiments, each touch sensor  20  outputs a signal in response to an effect of a pilot&#39;s finger touching or closely approaching a corresponding control device. Many different types of touch or proximity sensors capable of being integrated into a control device could be used. In accordance with one embodiment, the sensors can be capacitive-type touch sensors of types which are well-known for use as human interface devices. Capacitive sensing is a technology based on capacitive coupling which takes human body capacitance as input. Capacitive sensors detect anything that is conductive or has a dielectric constant different than that of air. Capacitive sensors can be constructed from many different media, such as copper, indium tin oxide and printed ink. There are two types of capacitive sensing systems: (1) mutual capacitance, where the object (such as a finger) alters the mutual coupling between two electrodes; and (2) self- or absolute capacitance, where the object (such as a finger) loads the sensor or increases the parasitic capacitance to ground. In both cases, the difference of a preceding absolute position from the present absolute position yields the relative motion of the object or finger during that time. In accordance with alternative embodiments, the sensors can be infrared detectors which react to infrared radiation, such as infrared radiation emitted by a pilot&#39;s finger. 
         [0029]    In accordance with a different design, rather than incorporating individual touch sensors into the design of the control devices (which may have different sizes and shapes), the human interface state of a control device can be monitored by an infrared camera mounted to the mode control panel. 
         [0030]    The control output processor  16  processes the touch sensor outputs and then sends display control signals to the display system  22  which cause the primary flight display of the latter to display symbology, graphical elements, icons, coloring, shading, highlighting, changes in font size, etc. which indicate to the pilot which control device he/she is touching, as will be described in more detail below with reference to  FIGS. 2 and 3 . 
         [0031]    The control output processor  16  processes the touch sensor outputs in accordance with an algorithm designed to discriminate each instance where a control device  18  of interest has been touched or nearly touched by a pilot in a predetermined manner. One embodiment of such an algorithm will be described later with reference to  FIG. 4 . After the touch sensor outputs have been processed, the control output processor  16  controls the primary flight display screen accordingly. For example, the control output processor  16  may execute a software application whereby an area of the primary flight display, e.g., an area on the screen that is associated with the particular pilot-actuated control device, is controlled to display a graphical element, symbol, icon, or add coloring, shading or highlighting that is designed to visually indicate to the pilot which control device he/she is touching or manipulating while his attention is directed to the primary flight display. 
         [0032]      FIG. 2  is a front view of a FMS mode control panel  14  in accordance with the embodiment. The mode control panel  14  provides control of the auto flight computer, flight director, altitude alert and autothrottle system. The mode control panel  14  is used to select and activate autopilot flight director system (AFDS) modes and establish altitudes, speeds and climb/descent profiles. The mode control panel  14  comprises a speed section  24 , a direction section  26 , a vertical path section  28 , and an altitude section  30 . In addition to knobs/wheel and switches, each section of the mode control panel  14  includes related display windows. 
         [0033]    For this embodiment, the speed section  24  comprises a speed knob/selection button  32 , an indicated airspeed (IAS)/MACH number speed mode selection switch  34 , a speed display window  36  that displays the speed selected, and mode selection buttons  38  with mode active indicator lights. The IAS/MACH speed mode selection switch  34  is a toggle switch that allows the pilot to choose between IAS and MACH number speed modes of operation, including alternately changing the speed display window  36  between IAS and Mach number displays. In operation, the mode selection buttons  38  can be pushed to engage a particular mode of guidance (i.e., LNAV, VNAV, FLCH or A/T (auto-throttle)) and can illuminate to indicate that the selected mode is active. 
         [0034]    A speed management module is engaged by pushing speed knob/selection button  32 . The term “module” as used herein, may refer to any combination of software, firmware, or hardware used to perform the specified function or functions. When speed knob/selection button  32  is pushed, the speed management module is synchronized to the current aircraft speed. Thereafter the speed of the aircraft is increased or decreased by rotating the speed knob/selection button  32 . During knob rotation, the indicated speeds in the speed display window  36  and in the primary flight display (not shown in  FIG. 2 ) are set to the selected speed. Pushing speed knob/selection button  32  a second time exits the speed management mode of operation and engages a speed transition module for returning control of the aircraft to the preprogrammed speed profile, such as, for example, a VNAV speed profile stored in the auto flight computer  10 . 
         [0035]    Referring again to  FIG. 2 , the direction section  26  of the mode control panel  14  comprises a heading knob/selection button  42 , a heading/track mode selection switch  44 , and a direction display window  46  that displays the selected heading or track. The heading/track mode selection switch  44  is a toggle switch that allows the pilot to choose between heading and track modes of operation and alternately changes the direction display window  46  and the primary flight display (not shown in  FIG. 2 ) references between vertical speed and FPA. A direction management module is engaged by pushing the heading knob/selection button  42 , thereby selecting Heading Select or Track Select as the roll mode. The bank angle is limited by the angular position of an outer knob or sleeve  48  (such a bank limit selector is well known in the art and will not be described in detail herein). Rotating the heading knob/selection button  42 , after it has been pushed, controls the direction of the airplane, i.e., rotation of the heading knob steers the airplane, and sets the heading or track in the direction display window  46  and in the primary flight display. A second depression of the heading knob/selection button  42  cancels pilot management of the airplane&#39;s direction. This results in the airplane intercepting and following the preprogrammed flight route entered into the auto flight computer  10  prior to takeoff or during the flight. That is, the airplane returns the LNAV mode of operation of the auto flight computer  10 . If the airplane is not on the preprogrammed flight route when pilot management of direction is cancelled, the airplane follows the heading or track determined by the angular position of the heading knob/selection button  42  until the preprogrammed flight route is captured. Pushing the heading HOLD switch  40  selects Heading Hold or Track Hold as the roll mode and maintains the current aircraft heading. 
         [0036]    Still referring to  FIG. 2 , the vertical path section  28  of the mode control panel  14  comprises a vertical speed wheel  52 , a vertical speed (VS)/flight path angle (FPA) mode selection switch  54 ; a vertical path display window  56  that displays the selected VS or FPA, and a VS/FPA switch  58  (with integrated light). Pushing the VS/FPA switch  58  engages a vertical path subroutine (i.e., the VS/FPA mode) and displays the current vertical speed or FPA in the vertical path display window  56 . The light of switch  58  indicates that the VS/FPA mode is engaged. The VS/FPA mode selection switch  54  is a toggle switch that toggles between vertical speed and flight path angle modes of operation. The vertical path subroutine is synchronized to the current vertical speed or flight path angle, depending upon the state of the VS/FPA mode selection switch  54 . The VS/FPA mode selection switch  54  alternately changes the vertical path display window  56  and primary flight display references between vertical speed and FPA. Rotation of the vertical speed wheel  52  in the up or down direction causes the selected criteria (vertical speed or flight path angle) to increase or decrease, depending upon the direction of rotation, and causes the vertical speed or FPA to be set in the vertical path display window  56  and primary flight display (not shown in  FIG. 2 ). When it is desired to terminate vertical path intervention, the pilot can push VS/FPA switch  58  a second time, which results in control of the airplane returning to the preprogrammed instructions stored in the auto flight computer  10 . That is, the airplane returns to following the VNAV profile instructions. 
         [0037]    Still referring to  FIG. 2 , the altitude section  30  of the mode control panel  14  comprises an inner altitude knob/selection button  62 , an outer altitude increment selector knob  64  and an altitude display window  66 . Rotation of the altitude knob/selection button  62  controls the numerical value displayed by the altitude display  66  and by the primary flight display. After the chosen numerical altitude is set, depression of the altitude knob/selection button  62  initiates a climb/descent to the selected altitude. The outer altitude increment selector knob  64  has two settings: AUTO—the altitude selector changes in 100-foot increments; and 1000—the altitude selector changes in 1000-foot increments. The altitude HOLD switch  68  engages Altitude Hold as the pitch mode. The AFDS commands pitch to maintain the current altitude when switch  68  is pushed. 
         [0038]    Other control panel devices depicted in  FIG. 2  are well known to persons skilled in the art (see, e.g., A/P, F/D, A/T ARM (L/R), CLB/CON, A/T, A/P DISENGAGE, and APP) and need not be described here. 
         [0039]    In accordance with the concept shown in  FIG. 1 , the control panel  14  seen in  FIG. 2  further comprises touch sensors (not shown in  FIG. 2 ) that are integrated into the various control devices depicted in  FIG. 2 , such as the speed knob/selection button  32 , the heading knob/selection button  42 , the vertical speed wheel  52 , and the altitude knob/selection button  62 . The control output processor executes an algorithm whereby a corresponding area on the primary flight display is modified as a function of which control panel device is being touched or nearly touched by the pilot. The changes to the primary flight display will now be described in more detail with reference to  FIG. 3 . 
         [0040]      FIG. 3  shows a primary flight display  70 . The display field is divided into a number of indicators  72 ,  74 ,  76 ,  78  and  80 . The indicators  74 ,  76 ,  80  and  78  (shown in  FIG. 3 ) are respectively associated with speed section  24 , direction section  26 , vertical path section  28 , and altitude section  30  of the control panel  14  (shown in  FIG. 2 ). 
         [0041]    The indicator  72  is a centrally located electronic attitude director indicator which is substantially rectangular in shape and has a central boresight box  82  representing the airplane longitudinal axis at the center of the box. On either side thereof are conventional stationary aircraft symbols  84  and  86 . An artificial horizon is provided by line  88 . The overall presentation by the electronic attitude director indicator  72  is substantially conventional. 
         [0042]    Adjacent and along the left-hand side of attitude director indicator  72  is an air speed indicator  74  comprising a vertically movable scale or “tape”  90  having graduations representing air speed values along the right-hand side thereof. The air speed indicator  74  further comprises a fixed pointer  92  which points inwardly toward the air speed scale  90 . The pointer  92  is provided with a window  94  digitally indicating the air speed in response to instrumentation of the aircraft. As the air speed changes, the scale or tape  90  moves vertically relative to the fixed pointer  92 . The tape  90  presents a range of speed values above and below the current speed, with the numerics being disposed immediately to the left of the corresponding scale graduations. Portions of the scale or tape above and below the viewable range are blanked from the presentation. Moreover, the scale is blanked at the location of window  94  which supplies the numerical readout of the current speed as a “rolling” number. The air speed indicator  74  further includes a pilot-controlled marker or “bug”  96  consisting of a pair of adjacent horizontal lines, with the current value of the selected air speed being numerically displayed at location  98  above the air speed presentation. When the selected air speed is attained, the marker or “bug”  96  will reach pointer  92 . 
         [0043]    Indicator  76  for aircraft heading comprises an area having the shape of a segment of a circle or compass rose which is easily comprehensible by the viewer. The indicator  76  is provided with a degree scale  102  along the upper, arc-shaped portion thereof adjacent to the attitude director indicator  74 , and like the previously described air speed indicator  76 , the scale  102  of heading indicator  78  moves with respect to a fixed vertical heading/track line  104  which indicates the current track according to the auto flight computer. For other than the segment of the heading display as illustrated in  FIG. 3 , the compass rose is blanked out. A selected heading/track bug  106  is displayed at an angular position relative to scale  102  that corresponds to the heading/track selected by the pilot using the mode control panel, while the scale  102  is also positioned in response to the instrumentation such that the heading/track line  104  points to the correct indicia as identified by the numerics displayed at 10-degree intervals underneath the scale  102 . In response to a change in the heading of the aircraft, the scale  102  will appear to rotate. 
         [0044]    A vertically disposed altitude indicator  78  is located adjacent the right-hand side of the attitude director indicator  72  in  FIG. 3 , and is provided with an altitude scale  108  along the left-hand side thereof. The altitude indicator  78  is further provided with altitude numerics to the right of appropriate indicia on the scale. The indicator is of the moving scale or moving tape type wherein the scale  108  moves with respect to a fixed pointer  110  as the altitude of the aircraft changes. Fixed pointer  110  includes an adjacent window  112  within which the correct altitude is digitally displayed in rolling number fashion. Thus, as altitude information from aircraft instrumentation changes, both the numerical indicia in window  112  and the position of the underlying tape  108  change accordingly. Altitude indicia for altitudes above and below the range depicted on the viewable scale or tape  108  are blanked, as is the scale beneath window  112 . Pointer  110  does not block the view of indicia along the left-hand side of altitude indicator  78 , but points fixedly toward such indicia. The current value of the pilot-selected altitude is numerically represented at location  114 . 
         [0045]    The primary flight display  70  shown in  FIG. 3  also includes a vertical speed indicator  80  comprising a scale  116  calibrated in thousands of feet per minute along the left-hand side thereof. The vertical speed indicator  80  is provided with a movable pointer  118  adapted to indicate the current vertical speed of the aircraft by pointing to the indicia of the scale  116 , which is fixed in position. Pointer  118  is angularly movable from an apparent origin to the right of the scale  116 , from which the pointer appears to extend radially outwardly. After the pilot selects a desired altitude, the vertical speed of the aircraft can be controlled so that pointer  118  points toward the selected altitude on the altitude indicator  78 , and under these circumstances the vertical speed will be optimal for leveling out at the desired altitude. Vertical speed indicator  80  may further comprises a bug (not shown) which indicates a desired vertical speed selected by the pilot. 
         [0046]    In accordance with the touch-sensitive hardware control concept disclosed herein, each time that the pilot touches or nearly touches a control panel device that incorporates a touch or proximity sensor, an associated portion of the primary flight display is modified to visually indicate to the pilot which control panel device he/she is touching or nearly touching while he/she is looking at the primary flight display. 
         [0047]    For the purpose of illustration,  FIG. 3  depicts a situation wherein the primary flight display has been modified to visually indicate that the pilot is touching the speed knob/selection button (item  32  in  FIG. 2 ) on the control panel. In accordance with this embodiment, the control output processor (item  16  in  FIG. 1 ) will cause the display of a contrasting colored rectangle  120  (indicated by the speckled rectangular area depicted in  FIG. 3 ) which surrounds the numeric target air speed display field  98  on the primary flight display. This visible change on the primary flight display indicates to the pilot viewing the primary flight display that he is touching or nearly touching the speed knob/selection button (item  32  in  FIG. 2 ) on the mode control panel. This feature allows the pilot to confirm that he is touching or manipulating the speed knob/selection button  32  without looking at the control panel. 
         [0048]    Similarly, in the case where the pilot is touching or nearly touching the altitude knob/selection button (item  62  in  FIG. 2 ) on the control panel, the control output processor (item  16  in  FIG. 1 ) can be programmed to cause the display of a contrasting colored rectangle which surrounds the numeric target altitude display field  114  of the primary flight display  70 . 
         [0049]    In the case where the pilot is touching or nearly touching the vertical speed wheel (item  52  in  FIG. 2 ) on the control panel, the control output processor (item  16  in  FIG. 1 ) can be programmed to cause the display of a contrasting colored border that surrounds the vertical speed indicator  80  of the primary flight display  70 . Alternatively, the vertical speed bug could be highlighted to indicate that the pilot was touching the vertical speed wheel. 
         [0050]    Instead of contrasting color borders such as the rectangular border  120  seen in  FIG. 1 , other types of visual indicators can be used to indicate which control device is being manipulated. For example, in response to detection of pilot contact with a control device, an associated area on the primary flight display may change color or have a pattern imposed thereon or a defined graphical symbol or icon could be imposed on or near the associated area. Alternatively the font size of numbers displayed in a field (e.g., field  98  in  FIG. 3 ) could be increased to indicate touching. 
         [0051]    For example, in the case where the pilot is touching or nearly touching the heading knob/selection button (item  42  in  FIG. 2 ) on the control panel, the control output processor (item  16  in  FIG. 1 ) can be programmed to cause color highlighting of an area  110  that overlies the selected heading/track bug  102  and an area overlying and bisected by a dashed heading/track bug line  106  on a heading indicator  76 , as illustrated in  FIG. 4 . (The area  110  is shown in  FIG. 4  without speckling to avoid obscuring the heading/track bug and line.) 
         [0052]    In accordance with one embodiment, the control output processor (item  16  in  FIG. 1 ) is programmed to execute the algorithm depicted in  FIG. 5 . Initially default display symbology is shown on the primary flight display (or other suitable cockpit display) without any touch-indicative highlighting (step  122 ). In response to a control knob X being touched by the pilot, an associated touch sensor outputs a predetermined signal to the control output processor (step  124 ). The control output processor then determines whether that predetermined signal has a duration greater than a first preset threshold, e.g., &gt;100 msec (step  126 ). If not, then no highlighting is displayed. If the predetermined signal has a duration greater than the first preset threshold, an area on the primary flight display which is associated with knob X is highlighted (step  128 ). The control output processor then determines whether the predetermined signal from the same touch sensor has been absent for a duration greater than a second preset threshold, e.g., &gt;500 msec (step  130 ). If not, then highlighting is continuously displayed. If the predetermined signal has been absent for a duration greater than the second preset threshold, then the routine returns to step  122  (i.e., default display symbology is shown on the primary flight display without any touch-indicative highlighting). 
         [0053]    The touch-sensitive hardware control concept disclosed hereinabove is not limited in its application to the mapping of mode control panel devices to areas on a cockpit or flight deck display. More generally, the concept may be applied to any physically located hardware control devices that have associated areas on a non-collocated display. 
         [0054]    While touch-sensitive hardware controls have been described with reference to particular embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the teachings herein. In addition, many modifications may be made to adapt a particular situation to the teachings herein without departing from the essential scope thereof. Therefore it is intended that the claims set forth hereinafter not be limited to the disclosed embodiment. 
         [0055]    As used in the claims, the term “computer system” should be construed broadly to encompass a system having at least one computer or processor, and which may have two or more interconnected computers or processors.