Abstract:
A control system for an aircraft refueling boom controls the movements of the boom in certain areas in a total field of movement volume of possible boom movements based on the location of the boom in the total field of movement volume and based on the current rate of movement of the boom in the total field of movement volume.

Description:
FIELD 
       [0001]    This disclosure pertains to an aircraft refueling boom and the aspect of its control system that controls the movement of the aircraft refueling boom in certain areas in the total field of movement volume of possible boom movements based on the location of the boom in the total volume of possible boom movements, the operator input to the control system and the current rate of movement of the boom. 
       BACKGROUND 
       [0002]    Aircraft refueling booms can be moved through a wide range of movement in response to operator input signals sent to the boom control system. The operator input signals are produced in response to manual manipulation of an input device by the operator of the boom. For example, an aircraft refueling boom can be controlled to move through a field of movement of the boom by an operator manually manipulating a joystick control device. The operator movement of the joystick forwardly or rearwardly would cause the control system to move the boom downwardly or upwardly, respectively. The operator movement of the joystick to the left or to the right would cause the control system to move the boom to the left or to the right, respectively. 
         [0003]    The aircraft refueling boom field of movement through which the boom can be moved in response to input by the operator is limited in order to avoid damage to the boom, damage to the aircraft being refueled, and damage to the tanker aircraft from which the boom extends. For example, the aircraft refueling boom field of movement is limited by the soft limit control system of the boom to avoid the boom impacting with the fuselage of the tanker aircraft. Such an impact could damage the boom or the refueling nozzle of the boom. Furthermore, such an impact could result in the boom damaging the fuselage of the tanker aircraft. Thus, aircraft refueling boom control systems that oppose certain control signals produced by an operator&#39;s manual movement of a control device to avoid damage to the boom, the refueling nozzle and the tanker aircraft fuselage are desirable. 
       SUMMARY 
       [0004]    The aircraft refueling boom soft limits control system of this disclosure controls movements of an aircraft refueling boom in response to control signals sent to the control system by an operator of the aircraft refueling boom. The control system controls the movements of the aircraft refueling boom within a total field of movement volume relative to the tanker aircraft deploying the boom. The total field of movement volume is a general conical volume that is defined by the length of the boom with the distal end of the boom being moved in a circle at the base of the conical volume and the proximal end of the boom connected to the tanker aircraft being at the apex of the conical volume. The total field of movement volume is surrounded by a movement limit threshold. The movement limit threshold is like an imaginary partition or wall that surrounds the total field of movement volume. The control system of the boom prevents the boom from crossing the movement limit threshold. The total field of movement volume is well spaced from the tanker aircraft fuselage or other structures of the tanker aircraft to avoid any damage to the tanker aircraft or the tanker aircraft structures resulting from the boom coming into contact with the tanker aircraft or the tanker aircraft structures. 
         [0005]    The total field of movement volume has a central movement volume. In the central movement volume the movement of the boom is unrestricted. The central movement volume is also a general conical volume that is defined by the length of the boom when the distal end of the boom is moved in a circle at the base of the central movement conical volume with the proximal end of the boom connected to the tanker aircraft being at the apex of the central movement conical volume. In the central movement volume the control system of the boom controls the movements of the boom in response to the operator&#39;s manual movements of a control device, for example a joystick. The control system does not impose any restrictions on the movements of the boom in response to the operator&#39;s movements of the joystick. In the central movement volume, the boom is free to move to the left or right and upwardly or downwardly as viewed by the operator of the boom in response to the control signals sent to the control system by the operator&#39;s manual movements of the joystick. The central movement volume is surrounded by a restricted movement threshold. The restricted movement threshold defines the outer bounds of the central movement volume. The restricted movement threshold is like an imaginary conical partition or wall within the total field of movement volume that separates the central movement volume from the remainder of the total field of movement volume. 
         [0006]    Surrounding the central movement volume and surrounding the restricted movement threshold is a restricted movement volume. The restricted movement volume is also a general hollowed conical volume that is larger than and surrounds the central movement volume. The restricted movement volume is positioned between the restricted movement threshold and the movement limit threshold. In the restricted movement volume, the control system places some restrictions on the movements of the boom resulting from the operator&#39;s manual movements of the joystick. For example, as the operator moves the joystick and sends input signals to the control system to cause the control system to move the boom from the central movement volume, through the restricted movement threshold and into the restricted movement volume, the control system senses the movement of the boom across the restricted movement threshold. The control system then opposes the operator&#39;s movements of the joystick and reduces or restricts the movement of the boom through the restricted movement volume in the direction of the boom chosen by the manual input of the operator. 
         [0007]    Basically, the control system progressively slows down the movement of the boom through the restricted movement volume as the boom approaches the movement limit threshold surrounding the total field of movement volume. Should the operator continue to operate the joystick to control movement of the boom to the movement limit threshold, the control system prevents further movement of the boom in the direction of the movement limit threshold. In this way, the control system restricts the movement of the boom to contain the boom in the total field of movement volume where the boom is spaced well away from its mechanical limits, the tanker aircraft fuselage and/or a tanker aircraft structures, preventing potential impact of the boom with the tanker aircraft fuselage or structures. 
         [0008]    In order to ensure that the control system prevents the boom from moving beyond the total field of movement volume and potentially reaching the boom&#39;s mechanical limits, contacting the tanker aircraft fuselage or structures of the tanker aircraft, the control system monitors the rate or speed at which the boom is controlled to move from the central movement volume, across the restricted movement threshold and into the restricted movement volume. By the control system monitoring the rate at which the boom moves from the central movement volume, through the restricted movement threshold and into the restricted movement volume, the control system can determine the force and amount of time required to overcome the inertia of the mass of the moving boom and control stopping of the boom movement as the boom reaches the movement limit threshold. For example, when the control system senses the boom moving at a first rate or speed of movement through the central movement volume and into the restricted movement area, the control system controls the actuators of the boom movement to exert a first force against the inertia of the boom for a first period of time to ensure that the movement of the boom through the restricted movement volume stops before the boom reaches the movement limit threshold. When the control system senses the boom moving at a second rate or speed of movement through the central movement volume and into the restricted movement volume, and the second rate of movement is larger than the first rate of movement, then the control system controls the actuators of the boom movement to exert a second force that is larger than the first force against the inertia of the boom movement for a second period of time to ensure that the boom stops moving through the restricted movement volume before the boom reaches the movement limit threshold. 
         [0009]    By sensing the rate or speed of movement of the boom through the central movement volume, across the restricted movement threshold and into the restricted movement volume, the control system ensures that a sufficient stopping force will be exerted against the inertia of the boom moving through the restricted movement volume in sufficient time to stop the movement of the boom when the boom reaches the movement limit threshold. 
         [0010]    The features, functions, and advantages that have been discussed can be achieved independently in various embodiments or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a flow diagram of aircraft production and service methodology. 
           [0012]      FIG. 2  is a block diagram of an aircraft. 
           [0013]      FIG. 3  is a representation of a perspective view of an aircraft supporting an aircraft refueling boom operated by the control system of this disclosure. 
           [0014]      FIG. 4  is a representation of a block diagram of a manually operated control device and a control system that controls the movements of the aircraft refueling boom of this disclosure. 
           [0015]      FIG. 5  is a representation of a diagram of the field of movement volume of the aircraft refueling boom, the central movement volume of the boom and the restricted movement volume of the boom controlled by the control system of this disclosure. 
           [0016]      FIGS. 6-9  are representations of movement of the aircraft refueling boom through the field of movement volume in response to manual input to the manual control device where the boom movements are controlled by the control system of this disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    Referring more particularly to the drawings, embodiments of the disclosure may be described in the context of an aircraft manufacturing and service method  10  as shown in  FIG. 1  and an aircraft  12  as shown in  FIG. 2 . During pre-production, exemplary method  10  may include specification and design  14  of the aircraft  12  and material procurement  16 . During production, component and subassembly manufacturing  18  and system integration  20  of the aircraft  12  takes place. Thereafter, the aircraft  12  may go through certification and delivery  22  in order to be placed in service  24 . While in service by a customer, the aircraft  12  is scheduled for routine maintenance and service  26  (which may also include modification, reconfiguration, refurbishment, and so on). 
         [0018]    Each of the processes of method  10  may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include without limitation any number of aircraft manufacturers and major-system subcontractors; a third party may include without limitation any number of venders, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on. 
         [0019]    As shown in  FIG. 2 , the aircraft  12  produced by exemplary method  10  may include an airframe  28  with a plurality of systems  30  and an interior  32 . Examples of high-level systems  30  include one or more of a propulsion system  34 , an electrical system  36 , a hydraulic system  38 , and an environmental system  40 . Any number of other systems may be included. Although an aerospace example is shown (aircraft, rockets), the principles of the invention may be applied to other industries, such as the automotive, railroad or tooling industry. 
         [0020]    Apparatus and methods embodied herein may be employed during any one or more of the stages of the production and service method  10 . For example, components or subassemblies corresponding to production process  18  may be fabricated or manufactured in a manner similar to components or subassemblies produced while the aircraft  12  is in service. Also, one or more apparatus embodiments, method embodiments, or a combination thereof may be utilized during the production stages  18  and  20 , for example, by substantially expediting assembly of or reducing the cost of an aircraft  12 . Similarly, one or more of apparatus embodiments, method embodiments, or a combination thereof may be utilized while the aircraft  12  is in service, for example and without limitation, to maintenance and service  26 . 
         [0021]    This disclosure pertains to an aircraft refueling boom and its control system that are similar to those disclosed in the international patent publication No. WO 2012/030347, which is assigned to the assignee of this application and is incorporated herein by reference. 
         [0022]      FIG. 3  is a representation of a tanker aircraft  42  having a refueling boom  44 . The movements of the refueling boom  44  are controlled by the soft limits control system of this disclosure in response to control signals sent to the control system by an operator of the aircraft refueling boom. The boom supports a nozzle  46  that communicates with fuel tanks (not shown) inside the tanker aircraft  42 . The boom  44  and the soft limits control system provide in-flight refueling to a refueling receiver  48  of a separate aircraft  50 . The soft limits control system controls the movements of the boom  44  in an upward or downward direction as viewed by the boom operator in the aircraft and represented by the arrow  52 , a left or right direction as viewed by the boom operator in the aircraft  42  and represented by the arrow  54 , or a combination of these directions within a total field of movement volume relative to the tanker aircraft  42  deploying the boom  44 . The soft limits control system controls the operation of rudders and elevator  56  on the boom  44  to move the boom  44  through the total field of movement volume. 
         [0023]      FIG. 4  is a representation of the soft limits control system  62  of this disclosure. As represented in  FIG. 2 , the soft limits control system  62  controls movements of the boom  44  in response to input signals received from a manual control device, such as a joystick  64  that is manually manipulated by an operator of the boom inside the aircraft  42 . In response to the manual manipulation of the joystick  64 , the soft limits control system  62  controls the rudders to move the boom left or right as represented by the arrow  54 , or the elevator to move the boom  44  upwardly or downwardly along the arrow  52 , or controls a combination of these movements. 
         [0024]    During operation of the boom  44 , situations can occur that are unexpected by the boom operator. Such situations can cause the boom operator to make manual movements of the joystick  64  that result in boom movements that could be dangerous to the tanker aircraft  42  or the refueling receiver  48  of the separate aircraft  50  being refueled by the tanker aircraft. For example, the boom operator could make movements of the joystick  64  that result in the boom being moved to a mechanical limit of the boom total field of movement where the boom has the potential for causing damage to itself, contacting and causing damage to the aircraft fuselage or a structure of the aircraft. The soft limits control system  62  is programmed to control the movements of the boom  44  in response to manual movements of the joystick  64  by the operator, and also to control the movements of the boom  44  that override control input signals from the joystick  64  and restrict movements of the boom that could potentially cause damage to the aircraft  42  and/or structures of the aircraft. 
         [0025]    In response to the operator of the boom  44  making manual movements of the joystick  64 , an input control signal  68  is sent from the joystick  64  to the soft limit control system  62 . The input control signal  68  is received by a summing junction  70  of the soft limit control system  62 . The summing junction  70  combines the input control signal  68  with a signal received from a feedback loop (to be described) and sends a signal to the boom control logic  72 . 
         [0026]    The boom control logic  72  includes fly by wire controller information that is used to determine a first control signal  74  that is output to the actuators  76  of the rudders and elevator  56 . The first control signal  74  controls the actuators  76  to position the rudders and elevator  56  to control the up or down movements or left to right movements of the boom  44  desired. 
         [0027]    The movement of the rudders and elevator cause the boom to move. The boom motion is sensed by the boom position sensors and one or more inertial measurement units. 
         [0028]    The one or more inertial measurement unit sensors  82  generate a second control signal  84  as feedback to the boom control logic  72 . The inertial measurement unit sensors  82  provide input regarding an actual angular rate and linear acceleration of movement of the boom  44 . 
         [0029]    Additionally, an output signal  80  from the boom dynamics  78  is provided to boom position sensors  86  which gather information on a position of the boom  44  relative to the aircraft  42 . An output signal  88  from the boom position sensors  86  is also provided to imposed limits  92  which include logic governing imposed limits applied to the boom  44 . For example, the imposed limits  92  of the control system  62  define a central movement volume in which there is unrestricted operator control of movements of the boom  44 , a restricted movement volume that surrounds the central movement volume and in which the control system  62  imposes some restrictions on boom movements, and a movement limit threshold that surrounds the restricted movement volume and prevents further movement of the boom  44  beyond the movement limit threshold. An output signal  94  of the imposed limits  92  is fed back to the summing junction  70  where the output signal  94  of the imposed limits  92  offsets or negates at least a portion of the input control signal  68  generated by the boom operators movements of the joystick  64 . 
         [0030]    As further described with reference to  FIGS. 5-10 , when the boom  44  is operated in a central movement volume, the operator of the boom  44  may move the boom with full control and no restrictions. The central movement volume is a general conical volume that is defined by the length of the boom  44  when the distal end of the boom or nozzle  46  is moved in a circle at the base of the central movement conical volume with the proximal end of the boom  44  connected to the tanker aircraft  44  being at an apex of the central movement conical volume. In the central movement volume, the boom is free to move to the left or right and upwardly or downwardly as viewed by the operator of the boom in response to the input control signal  68  sent to the control system  62  by the operator&#39;s manual movement of the joystick  64 . The central movement volume is surrounded by a restricted movement threshold. The restricted movement threshold defines the outer bounds of the central movement volume. The restricted movement threshold is like an imaginary conical partition or wall that surrounds the central movement volume. Surrounding the central movement volume and surrounding the restricted movement threshold is a restricted movement volume. When the boom  44  moves from the central movement volume, through the restricted movement threshold and into the restricted movement volume, the output signal  94  from the imposed limits  92  received at the summing junction  70  reduces or partially offsets the input control signal  68  so that a greater or more pronounced operator input is required at the joystick  64  to generate an input control signal  68  that may at least partially overcome the output signal  94  of the imposed limits  92  at the summing junction  70 . When the boom  44  reaches the movement limit threshold that surrounds the restricted movement volume, the output signal  94  from the imposed limits  92  entirely offsets or blocks the input control signal  68 . As a result, no matter to what extent the operator of the boom  44  moves the joystick  64  in the direction where the boom  44  has reached the movement limit threshold, the output signal  94  from the imposed limits  92  applied to the summing junction  70  cancels the control input signal  68 . 
         [0031]      FIG. 5  is a representation of a total field of movement of the boom  44  relative to the aircraft  42  that is controlled by the control system  62 . In  FIG. 5 , the total field of movement is represented by the solid line  96 . Although the total field of movement  96  is shown in two dimensions in  FIG. 5 , it should be understood that the boom  44  and the nozzle  46  of the boom move in a three-dimensional volume. During refueling operations, the nozzle  46  of the boom  44  is moveable by the control system  62  in the volume having the general configuration of a truncated cone at the bottom of the total field of movement  96  shown in  FIG. 5 . The boom  44  moves through the volume having the general configuration of a cylinder at the top of the total field of movement volume  96  represented in  FIG. 5 . The solid line  96  represents a movement limit threshold in the control logic of the control system  62 . The movement limit threshold  96  is like an imaginary partition or wall that surrounds the total field of movement volume. The control system  62  controls the movement of the boom  44  and prevents the boom  44  from crossing the movement limit threshold  98 . The total field of movement volume  96  within the movement limit threshold  98  is well spaced from the tanker aircraft  42  to avoid any damage to the tanker aircraft  42  or tanker aircraft structures resulting from the boom  44  coming into contact with the tanker aircraft or the tanker aircraft structures. 
         [0032]    The total field of movement volume  96  has a first, central movement volume  100 . The central movement volume  100  is surrounded by a restricted movement threshold  102 . The central movement volume  100  within the restricted movement threshold  102  has a general configuration of a truncated cone that is defined by the length of the boom  44  when the distal end or nozzle  46  of the boom is moved in a circle at the base of the truncated cone and with the proximal end of the boom connected to the tanker aircraft  42  being at the apex. In the central movement volume  100  defined by the restricted movement threshold  102 , movement of the boom is unrestricted by the control system  62 . In the central movement volume  100 , the control system  62  controls movements of the boom  44  in response to the operator&#39;s manual movements of the joystick  64 . The control system  62  does not impose any restrictions on the movements of the boom  44  in response to the operator&#39;s movements of the joystick  64 . In the central movement volume defined by the restricted movement threshold  102 , the boom  44  is free to move to the left or right and upwardly or downwardly as viewed by the operator of the boom in response to the input control signals  68  sent to the control system  62  by the operator&#39;s manual movements of the joystick  64 . The restricted movement threshold  102  defines the outer bounds of the central movement volume  100 . The restricted movement threshold  102  is like an imaginary partition or wall within the movement limit threshold  98  that separates the central movement volume  100  from the remainder of the total field of movement volume  96  within the movement limit threshold  98 . 
         [0033]    Surrounding the central movement volume  100  is a second, restricted movement volume  104 . The restricted movement volume  104  is positioned outside of the central movement volume  100  and surrounds the central movement volume  100  and the restricted movement threshold  102 . The restricted movement volume  104  extends from the restricted movement threshold  102  to the movement limit threshold  98 . The restricted movement volume  104  is also a general hollowed conical volume that is larger than and surrounds the central movement volume  100  and the restricted movement threshold  102 . In the restricted movement volume  104 , the control system  62  puts some restrictions on the movements of the boom  44  resulting from the operator&#39;s manual movements of the joystick  64 . 
         [0034]      FIGS. 6-9  are representations of the movement of the aircraft refueling boom  44  through the total field of movement volume  96  in response to manual input to the joystick  64  where the boom movements are controlled by the control system  62 . 
         [0035]      FIG. 6  is a representation of a first situation in which the boom  44  is positioned in the central movement volume  100  within the restricted movement threshold  102 . In the central movement volume  100 , movement of the boom  44  is unrestricted by the control system  62 . The boom  44 , the position of which is being monitored by the control system  62 , is at a first position within the central movement volume  106 . The joystick  64  is not subject to any control input from the operator. Because no control input is applied by the operator to the joystick  64 , the boom  44  remains at its current position represented in  FIG. 6 . 
         [0036]      FIG. 7  is a representation of a second situation in which the boom operator moves the joystick  64  forwardly, sending an input control signal  68  to the control system  62 . In response to the forward movement of the joystick  64 , the boom  44  moves downwardly in the central movement volume  100  to a second position below the first position of the boom  44  represented in  FIG. 6 . Because the position of the boom  44  represented in  FIG. 7  is still in the central movement volume  100  where movement of the boom is unrestricted by the control system  62 , the control system  62  fully implements the movement of the boom  44  in response to the input control signal  68  received from the joystick  64 . 
         [0037]      FIG. 8  is a representation of further downward movement of the boom  44  in the central movement volume  100  resulting from the continued presence of the joystick  64  in its pushed forward position. As represented in  FIG. 8 , the boom  44  has been moved from its first position represented in  FIG. 6  to a third position within the central movement volume  100  adjacent the restricted movement threshold  102 . Because the input control signal  68  produced by the pushed forward position of the joystick  64  continues to be applied to the control system  62 , the boom  44  continues to move downwardly in response to the input control signal  68  at a same rate within the central movement volume  100 . Because the boom  44  continues to be moved in the central movement volume  100 , the input control signal  68  resulting from the pushed forward position of the joystick  64  is fully implemented without any reduction in response from the control system  62 . 
         [0038]      FIG. 9  is a representation of movement of the boom  44  to a fourth position. A continued positioning of the joystick  64  in the pushed forward position by the boom operator directs the boom  44  to move in the same direction of movement as represented in  FIGS. 7 and 8  with the boom  44  moving through the restricted movement threshold  102  and through the restricted movement volume  104  toward the movement limit threshold  98 . 
         [0039]    In response to the boom  44  moving through the restricted movement threshold  102  and into the restricted movement volume  104 , the control system  62  reduces the response of the boom  44  to the pushed forward position of the joystick  64  by the boom operator. Thus, if the boom operator&#39;s pushed forward positioning of the joystick  64  is continued, the control system  62  controls the boom  44  to respond more slowly. If the boom operator wishes to move the boom  44  in the same direction at the same rate, the operator must increase a magnitude of the manual input to the joystick  64  and push the joystick further forward. 
         [0040]    The control system  62  progressively slows down the movement of the boom  44  through the restricted movement volume  104  as the boom  44  approaches the movement limit threshold  98  surrounding the total field of movement volume  96 . Should the boom operator continue to operate the joystick  64  to control movement of the boom  44  to the movement limit threshold  98 , the control system  62  takes over complete control of the boom  44  and stops the movement of the boom at the movement limit threshold  98 . In this way, the soft limits control system  62  restricts the movement of the boom  44  to contain the boom in the total field of movement volume  96  where the boom is spaced well away from its mechanical limits, the tanker aircraft fuselage and/or a tanker aircraft structure, preventing potential impact of the boom  44  with the tanker aircraft fuselage or structure. 
         [0041]    In order to insure that the control system  62  prevents the boom  44  from moving beyond the total field of movement volume and potentially reaching its mechanical limits, contacting the tanker aircraft  42  or structures of the tanker aircraft, the control system  62  monitors both the position of the boom  44  in the total field of movement volume  96  and the rate or speed of movement at which the boom  44  is controlled to move from the central movement volume  100 , across the restricted movement threshold  102  and into the restricted movement volume  104 . By the control system  62  monitoring the position of the boom  44  in the total field of movement volume  96  and the rate at which the boom moves from the central movement volume  100 , through the restricted movement threshold  102  and into the restricted movement volume  104 , the control system  62  can determine the force and amount of time required to overcome the inertia of the mass of the moving boom  44  and control stopping of the boom movement as the boom  44  reaches the movement limit threshold  98 . For example, when the control system  62  senses the boom  44  moving at a first rate or speed of movement through the central movement volume  100 , across the restricted movement threshold  102  and into the restricted movement volume  104 , the control system  62  controls the actuators  76  to move the rudders and elevator  56  to positions relative to the boom  44  where the rudders and elevator  56  exert a first force against the inertia of the boom  44  for a first period of time to ensure that the movement of the boom  44  through the restricted movement volume  104  stops before the boom reaches the movement limit threshold  98 . When the control system  62  senses the boom moving at a second rate or speed of movement through the central movement volume  100 , through the restricted movement threshold  102  and into the restricted movement volume  104  where the second rate or speed of movement is greater than the first rate or speed of movement, the control system  62  controls the actuators  76  to move the rudders and elevator  56  to positions relative to the boom  44  where the rudders and elevator  56  exert a second force that is larger than the first force against the inertia of the boom movement for a second period of time to ensure that the boom  44  stops moving through the restricted movement volume  104  before the boom reaches the movement limit threshold  98 . 
         [0042]    By sensing both the position of the boom  44  in the total field of movement volume  96  and the rate or speed of movement of the boom through the central movement volume  100 , across the restricted movement threshold  102  and into the restricted movement volume  104 , the control system  62  ensures that a sufficient stopping force in sufficient time will be exerted against the inertia of the boom moving through the restricted movement volume  104  to stop the movement of the boom  44  when the boom reaches the movement limit threshold  98 . 
         [0043]    Although the operation of the boom soft limits  62  controlling the rate of movement of the boom  44  has been described above with reference to  FIGS. 6-9  for downward movement of the boom through the total field of movement volume  96 , it should be understood that the boom soft limits  62  control left and right movements of the boom  44 , upward and downward movements of the boom  44  and combinations of these movements through the total field of movement volume  96  in the same manner. 
         [0044]    As various modifications could be made in the construction of the aircraft refueling boom soft limits control and its method of operation herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present disclosure should not be limited by any of the above described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.