Abstract:
A method for producing a connector, in particular for repair, in particular in the field of aviation and aerospace, including the steps of: providing a base layer; attaching a first layer of fibre composite material having a first rigidity to the base layer; attaching a second layer of fibre composite material having a second rigidity to the first layer, offset therefrom, the second rigidity being greater than the first rigidity; and riveting the first layer to the base layer and riveting the second layer to the first layer and to the base layer.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of the French patent application No. 20120059072 filed on Sep. 27, 2012, the entire disclosures of which are incorporated herein by way of reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to an alarm method and device against inappropriate actuation of an aircraft rudder bar by a pilot during directional control of the aircraft. 
         [0003]    It is known that directional control of an aircraft is mainly ensured by an articulated rudder, able to rotate in two opposite directions of rotation between an aerodynamically neutral position and a stopped position of maximum rotation. To this end, the rudder is controlled by a mobile control facility (rudder bar) available to the aircraft pilot. This facility is generally equipped with two pedals, the respective depression of which causes the facility to travel in two opposite directions, associated, respectively, with the two opposite directions of rotation of the rudder. In particular, this rudder bar controls the rotation of the rudder in such a way that the amplitude of the rotation of said rudder depends on the amplitude of the rudder bar travel. Consequently, a depression of the right pedal, for example, conveys the wish of the pilot to cause a yawing moment tending to move the nose of the aircraft to the right, this moment being obtained by a deflection of the rudder to the right. Thus, in a few special cases, the pilot can act on the rudder bar with the aim of modulating the aerodynamic forces being applied to the aircraft, so as to modify or control the lateral path. These special cases are limited, like the control of engine failure and the alignment maneuver, to situations during a crosswind landing. 
         [0004]    Nevertheless, this steering facility being available to the pilot in all the phases of flight, it can occur that, in especially dynamic and unusual situations, the pilot actuates the rudder bar in a wholly inappropriate manner. This inappropriate actuation, in these phases of flight, can potentially generate excessive loads on the vertical stabilizer. 
         [0005]    Furthermore, to protect the aircraft, when the speed of the aircraft exceeds a speed threshold, it is possible to limit the rudder rotation in a manner inversely proportional to the speed of the aircraft, i.e. to make the rudder&#39;s TLU (Travel Limiter Unit) stop dependent on the speed of the aircraft, with the aim of limiting the stresses to which said aircraft is subjected at high speeds and, thus, of enabling the performance of yaw maneuvers, including at high speed. 
         [0006]    It can however occur, even with the travel limiter device, that actuation of the rudder bar inversely coordinated with the position of the rudder be such that the aircraft can experience excessive loads on the vertical stabilizer. 
         [0007]    The present invention has the object of preventing such a risk to the aircraft during directional control of the aircraft. It concerns an alarm method making it possible to alert a pilot to an inappropriate actuation of the aircraft rudder bar. 
       SUMMARY OF THE INVENTION 
       [0008]    To this end, according to the invention, said alarm method against inappropriate actuation of a rudder bar by a pilot, said rudder bar being capable of being moved in two opposite directions by the pilot to control a rudder, said rudder being able to turn in two directions of rotation up to a maximum rotation position in each of the two directions, one of the directions of the rudder bar being associated with one of the directions of rotation of the rudder and the other direction of the rudder bar being associated with the other direction of rotation of the rudder, 
         [0009]    is noteworthy in that: 
         [0010]    a) the current position of the rudder bar is monitored in order to be able to detect when the rudder bar reaches a so-called extreme position, for which the rudder reaches one of its maximum rotation positions; and 
         [0011]    b) when it is detected that the rudder bar reaches an extreme position, for which the rudder therefore reaches one of its maximum rotation positions, a check is made to verify whether, within a predetermined time period after having reached this position, the following alarm activation conditions are met: the rudder successively returns to a neutral position and re-exits this neutral position again; and 
         [0012]    c) when said alarm activation conditions are met during said predetermined time period, an alarm is triggered. 
         [0013]    Thus, thanks to the invention, when the pilot performs the series of specific actuations of the rudder bar resulting in the rudder being successively brought, during a very short predetermined time period, preferably three seconds, from an extreme position (TLU stop reached by the rudder) to a neutral position, then on exiting this neutral position (and this whatever the direction of exit), he is automatically warned of the non-conformity of such a maneuver, which allows him or her to be aware of this situation and act accordingly. 
         [0014]    Advantageously, in step a):
       a current rudder bar position value is received, emitted by at least one conventional ELAC-type system which is associated with said rudder bar and which expresses this position value in a rudder unit; and   the current rudder bar position value, expressed in a rudder unit, is compared to a position value representative of the maximum rotation position of the rudder for the current speed of the aircraft, said maximum rotation position depending on the speed of the aircraft.       
 
         [0017]    In the context of the present invention, the fact that a position value of the rudder bar is expressed in a rudder unit means that the rudder bar&#39;s position is taken into account, but that this position is defined, not as an angle of rotation of the rudder bar, but as a unit (particularly a deflection angle value) which illustrates the amplitude of the deflection of the rudder, generated by this position of the rudder bar. 
         [0018]    Furthermore, advantageously in step b), to verify the position of the rudder in relation to the neutral position, a current rudder position value, expressed in a rudder unit, is compared to a current neutral position value. In the context of the present invention, this current neutral position value corresponds to a fraction of the current value of the maximum rotation position, preferably to half of the current value of the maximum rotation position. 
         [0019]    The rudder is thus considered to be:
       located in the neutral position, when the current position value of the rudder bar, expressed in a rudder unit, is less than or equal to said neutral position value; and   exited from the neutral position, when the current position value of the rudder bar, expressed in a rudder unit, is greater than said neutral position value.       
 
         [0022]    Furthermore, advantageously, it is possible to limit said neutral position value to predetermined values. Such a limitation makes it possible to guarantee that given the sampled data from ELAC (supplying the position of the pedals) and that acquired by a FAC (Flight Augmentation Computer), the neutral position can be detected whatever stress the pilot applies to the pedals. 
         [0023]    Moreover, advantageously when an autopilot system of the aircraft is engaged, it is detected at step a) that the rudder has reached a maximum rotation position, when additionally the current position of the rudder bar exceeds a predetermined value, for example 5°. 
         [0024]    Furthermore, advantageously, the triggering of the alarm is inhibited when at least one of the following conditions is met:
       the aircraft speed is below a predetermined speed;   an engine failure of the aircraft is detected; and   no valid rudder bar position value is available.       
 
         [0028]    When an alarm is triggered, it can be maintained during a time interval of predetermined duration, at least approximately equal to five seconds. 
         [0029]    Moreover, this alarm may be triggered in the form of a visual or sound signal for the attention of the pilot. 
         [0030]    The present invention also relates to an alarm device against inappropriate actuation of a rudder bar by the pilot of an aircraft, particularly a cargo airplane. 
         [0031]    To this effect, according to the invention, said alarm device is noteworthy in that it comprises:
       means for providing the current position of the rudder bar   means for providing a maximum rotation position of the rudder;   means for monitoring the current position of the rudder bar so as to be able to detect when the rudder bar reaches a so-called extreme position, for which the rudder reaches one of its maximum rotation positions, and when such a situation is detected, to verify whether, within a predetermined time period after having reached this extreme position, the following alarm activation conditions are met: said rudder successively returns to a neutral position and re-exits this neutral position; and   for alarm means emitting an alarm when said alarm activation conditions are met during said predetermined time period.       
 
         [0036]    Preferably, said alarm means emit, simultaneously, a visual alarm and a sound alarm. 
         [0037]    Furthermore, in a particular embodiment, said alarm device also comprises means for inhibiting said alarm means. 
         [0038]    The device according to the present invention has the aim of detecting mainly particular positions of the pedals of the rudder bar making it possible to determine that a TLU stop has been reached by the rudder, then that, within a predetermined time period (preferably three seconds), this rudder has returned to neutral and then re-exited from neutral in any direction. 
         [0039]    The present invention also relates to:
       an aircraft directional control system, comprising at least one rudder bar that can be actuated by a pilot of the aircraft, means for generating an electric command signal representing the position of the rudder bar, and computing means which receive this electric command signal and automatically generate control commands which are transmitted to actuation means of a rudder of the aircraft; and/or   an aircraft, in particular a cargo airplane,       
 
         [0042]    which are equipped with an alarm device, such as the one previously mentioned. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0043]    The figures of the appended drawing will clearly demonstrate how the invention may be embodied. In these figures, identical references denote similar elements. 
           [0044]      FIG. 1  is the block diagram of an embodiment of an aircraft directional control system comprising an alarm device according to the invention. 
           [0045]      FIG. 2  is the block diagram of an alarm device according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0046]    The device  10  according to the invention and represented diagrammatically in  FIG. 2  is intended to alert a pilot in the event of an inappropriate actuation by this pilot of a rudder bar  2  of an aircraft, in particular of a cargo airplane. This device  10  is associated with a conventional directional control system  1  of the aircraft, which is represented diagrammatically in  FIG. 1 . 
         [0047]    This directional control system  1  comprises, conventionally and generally:
       said rudder bar  2  (embodied in the form of pedals), of which a first unit  2 A may be actuated by the pilot (pedals  2 Ar,  2 Al), and of which a second unit  2 B linked to said first unit  2 A may be actuated by the co-pilot (pedals  2 Br,  2 Bl);   means  3  associated with said rudder bar  2 , which determine its position and which generate an electric command signal representative of this position;   a flight control computer  4  which receives this electric command signal via an electrical connector  5  and which generates control commands using the latter; and   actuation means  6  of a rudder  7  of the aircraft, to which are transmitted these control commands via an electrical connection  8 . These actuation means  6  deflect the rudder  7  (as illustrated by a connection  9  in dot-dash lines) by a deflection value representative of the control commands thus received.       
 
         [0052]    The rudder  7  is articulated and can turn in two opposite directions of rotation, around a vertical axis. It is able to pivot, in each of the two directions of rotation, between an aerodynamically neutral position and a maximum rotation position. 
         [0053]    The rudder bar  2  is intended, when the aircraft taxis on the ground or is in flight, to control the rotation of the rudder  7 , around its axis, in both directions. To this end, each unit  2 A and  2 B of the rudder bar  2  is able to turn around a vertical axis following two opposite directions of rotation which are associated respectively with the two directions of rotation of the rudder  7 . In order to do this, each unit  2 A and  2 B of the rudder bar  2  is provided with two pedals respectively left ( 2 Al,  2 Bl) and right ( 2 Ar,  2 Br), a depression of the left pedal being able to cause a rotation of the rudder bar in the direction of rotation associated with the leftward direction of rotation of the rudder  7 , whereas a depression of the right pedal is able to cause a rotation of said rudder bar in the direction of rotation associated with the rightward direction of rotation of the rudder  7 . 
         [0054]    The rudder bar  2  can thus pivot about its axis, between a position for which there is no command to rotate the rudder  7  and a maximum position for which the rotation of said rudder bar  2  is at a maximum. Between these two positions, the rudder bar  2  goes through a position (referred to as extreme in the context of the invention) for which the position of maximum rotation (to the left or the right) of the rudder  7  is reached. 
         [0055]    According to the invention, said device  10  comprises, as represented in  FIG. 2 :
       means  11  for providing the current position of the rudder bar  2 ;   means  12  for providing a maximum rotation position (TLU stop) value of the rudder  7 ;   means  13  for monitoring the current position of the rudder bar  2  in such a way as to detect when the rudder bar  2  reaches an extreme position, for which the rudder  7  reaches one of its positions of maximum rotation, and when such a situation is detected for verifying whether, in a predetermined time period (for example three seconds) after having reached this extreme position, the following alarm activation conditions are met: said rudder  7  successively returns to a neutral position and re-exits this neutral position; and   alarm means  14  for emitting an alarm when said alarm activation conditions are met during said predetermined time period.       
 
         [0060]    When they are triggered, said alarm means  14  preferably emit, simultaneously, a visual alarm and a sound alarm, as specified below. 
         [0061]    Furthermore, in a particular embodiment, said device  10  comprises, additionally, means  15  for inhibiting said alarm means  14 . 
         [0062]    Thus, when a pilot of the aircraft performs the series of particular actuations of the rudder bar  2  resulting in the rudder  7  being successively brought, within at the most a very short predetermined time, for preference three seconds, from an extreme position (TLU stop reached by the rudder  7 ) to a neutral position, then on the exit from this neutral position (and this whatever the direction of exit), the device  10  automatically warns the pilot, via the alarm means  14 , of the non-compliance of such a maneuver, which allows him or her to gain awareness of this situation and to act accordingly. 
         [0063]    The means  11  that provide a value for the rudder bars current position include a unit comprising at least one ELAC-type system. Usually, such a unit comprises two ELAC systems, each of which carries out the acquisition and monitoring of two sensors, each of which detects the position of the pedals  2 A of the pilot and the other of which detects the position of the pedals  2 B of the co-pilot. The values of the two sensors of each ELAC system are then compared. If an inconsistency is detected or an ELAC system presents a malfunction, the position value of the ELAC system is not considered valid. 
         [0064]    The current position value of the rudder bar  2 , provided by such a unit, (means  11 ), has already been transcribed as a rudder position. In fact, it is expressed in a rudder unit, that is to say in a unit (particularly a deflection angle value) that indicates the amplitude of the deflection of the rudder  7 , generated by the current position of the rudder bar  2 . This value is then retained under its absolute value (using means  16 .) 
         [0065]    Moreover, to obtain a homogenous detection threshold over the whole range of variation of the TLU, means  17  are provided to correct this pedal position, as a function of measures (rudder bar cycles) carried out on the aircraft during production (on each type of aircraft, since the characteristics of the linkages and the elasticity of the cables differ.) 
         [0066]    This current position value, thus corrected, is then used by the means  13  which are preferably incorporated into an FAC (or Flight Augmentation Computer), which usually already uses such a current position value received from the ELAC systems, which makes it possible to simplify the implementation of the present invention. 
         [0067]    More precisely, this current position value is addressed to a binary comparator  18  of A&gt;B type which compares this current value to a value obtained by a summing amplifier  19 . This summing amplifier  19  adds a predetermined value (generally 1°) to the TLU value (representing the current maximum rotation position of the rudder  7 ) generated by said means  12  in order to avoid premature detection. Said maximum rotation position depends on the (current) speed of the aircraft. 
         [0068]    In the example of  FIG. 2 , this current position value is also addressed:
       to a comparator  20  of A&gt;B type, which compares this current value to a predetermined value, preferably 5°, as specified below; and   to a comparator  21 , also of A&gt;B type, which compares this current value to a neutral position value, as specified hereinafter.       
 
         [0071]    The output from the comparator  18  is addressed:
       on the one hand, to an input of an AND logic gate  22 , the other input of which is linked to a NOT logic element  23  which receives from an autopilot system  24  the information that the latter has been activated. The logic gate  22  is thus set to the value 1 if, simultaneously, said current position value is higher than said current TLU value and the autopilot system  24  is not engaged; and   on the other hand, to an input of an AND logic gate  25 , of which the two other inputs are connected to the output of the autopilot system  24  and to the output of the comparator  20  respectively. The latter elements are applied in the special situation where the autopilot system  24  is engaged.       
 
         [0074]    Thus, when the autopilot system  24  is engaged, the detection “TLU reached” is maintained to enable the possible detection of a sequence of pedal actions beginning under automatic pilot. In this operating mode, the stiffness of the directional artificial feel, which is responsible for the strain experienced while deflecting the pedals, is considerably increased by the activation of a solenoid. Given this stiffening and the elongation under load of the control cables between the pedals and the rudder  7 , the travel of the rudder  7  begins at a larger deflection of the pedals. As a consequence, so as to desensitize the alarm when the autopilot system  24  is engaged as regards involuntary actions on the pedals while cruising, when the TLU alarm thresholds are low, a minimum threshold of pedal travel, preferably of 5°, is added to this detection “TLU reached”. 
         [0075]    The outputs of the logic gates  22  and  25  are addressed to an OR logic gate  26  which is set to the value “1” to indicate that the rudder  7  has reached the TLU stop, when:
       either the current position value of the rudder bar  2  exceeds by 1 degree the value of the TLU stop, for which the rudder  7  reaches one of its maximum rotation positions;   or the particular conditions following the engagement of the autopilot system  24  have been met.       
 
         [0078]    When the OR logic gate  26  switches to 1, checks are implemented during a predetermined period of time, preferably three seconds, as indicated by an element  27 . This OR logic gate  26  is connected to the inputs of two AND logic gates  28  and  29 . 
         [0079]    Thus the following checks are performed:
       on the one hand, whether the rudder  7  is brought to a neutral position using the AND logic gate  28 , the other input of which is connected to a NOT logic element which is additionally connected to the output of the comparator  21 . The output of the comparator  21  switches to 1 (current position value higher than the neutral position value) when the rudder  7  is outside the neutral position; and   on the other hand, whether the rudder  7  has again exited from the neutral position, using the AND logic gate  29 , the other input of which is connected directly to the output of said comparator  21 .       
 
         [0082]    The comparator  21  receives at its input a neutral position value which is calculated by an element  33 . This element  33  calculates a neutral position value which corresponds to a fraction of the maximum rotation position value of the rudder  7 , received from the means  12 , preferably half of this maximum rotation position value. 
         [0083]    A means  34  of setting a particular limit is also provided. Since the TLU position varies with the aircraft speed, the neutral position has been arbitrarily set to the theoretical TLU value divided by 2. Given the variation of the TLU position, this detection of the neutral has been limited to 3° per maximum value and to 1.5° per minimum value. This minimum value guarantees that given the samples from ELAC (providing the position of the pedals) and FAC (for acquisition) the neutral position can be detected whatever the pressure of the pilot on the pedals. 
         [0084]    The two AND logic gates  28  and  29  are connected to an AND logic gate  35  which activates the alarm means  14  so that they trigger an alarm when its output is set to 1, i.e. when the outputs of gates  28  and  29  are both set to 1. This situation occurs when, after having reached the TLU stop, the rudder  7  is returned to the neutral position (gate  28 ) and has re-exited it (gate  29 ), doing so during a predetermined time period (element  27 ). This alarm generated by the means  14  which are, for example, part of a central Flight Warning Computer, is maintained for a predetermined time period, for example five seconds, as illustrated by an element  36 . 
         [0085]    The alarm triggered by the means  14  can manifest in the form of:
       a visual signal, emitted by signalization means  33  (such as a screen, LEDs, etc.) receiving the command to trigger said alarm; and/or   a sound signal, emitted by sound-emitting means  40  receiving the command to trigger said alarm; and/or   yet any other type of suitable signal.       
 
         [0089]    Said alarm means  14  preferably emit, simultaneously:
       a sound alarm, for example in the form of a double emission by a synthetic voice of a message of the type “Stop rudder input” demanding the cessation of the rudder bar actuation; and   a visual alarm, in the form of a flashing light signal.       
 
         [0092]    Additionally, the inhibition means  15  comprise conditions that are transmitted to the input of an AND logic gate  37 , which is arranged between gate  35  and element  36 , and the operation of which inhibits the alarm. In a schematic and simplified manner, the various inputs of the AND logic gate  37  are schematized by an element  38  in  FIG. 2 . Preferably, said inhibition means  15  inhibit the triggering of the alarm when at least one of the following conditions is met:
       aircraft speed (particularly of CAS type) is below a predetermined speed threshold;   a failure of at least one engine of the aircraft is detected in the usual manner; and   no valid position value of the rudder bar  2  is available.       
 
         [0096]    As is apparent from the foregoing specification, the invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. It should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art.