EP1462756A1 - Method of defence of a vehicle or a structure against a threat such as a projectile and device to carry out said method - Google Patents

Abstract

The double acting pyrotechnic actuator (1) incorporates two pyrotechnic charges (8a,8b) each connected to distinct chambers (4a,4b) separated by a piston (5). The actuator positioning method consists of successively controlling the two charges in sequence so as to ensure, by the action of the second charge, a braking of the piston displacement which was controlled by the first charge. The time gap between the initiation of each charge is chosen to ensure the desired positioning of the piston. Independent claims are included for a pyrotechnic actuator and a vehicle defense device implementing the method.

Description

The technical field of the invention is that of methods and devices for defending a vehicle or structure against a threat such as a projectile (missile or rocket).

We know from patent FR2809172 a device for protection of a vehicle using a launcher tube of a projectile. The tube can be oriented in at least one plan by a single or double acting pyrotechnic cylinder.

This cylinder allows the device to have several possible launch directions. Each direction of launch corresponds to a position of the cylinder piston. So a single-acting cylinder gives the tube two positions different: that corresponding to the cylinder in the rest state and that corresponding to the activated cylinder.

A double-acting cylinder gives the tube three different positions: that corresponding to the cylinder in the state of rest and the two extreme positions corresponding to initiations of each of the two pyrotechnic charges.

The effectiveness of this device is limited because only three directions of fire are possible. It is therefore necessary to provide several launching devices having different orientations with respect to the vehicle.

We also know from patent FR2722873 a defense device in which a turret is oriented on site and in deposit by electric motors. The motors are controlled and allow to obtain any what orientation desired for the turret. So he is possible to launch a defense ammunition according to the optimal direction to counter the threat.

This defense system is however heavy and bulky and the electrical power it requires is also important.

It is the object of the invention to propose a method of defense of a vehicle or a structure without such disadvantages.

Thus the method according to the invention makes it possible to launch a defense ammunition in the optimal direction while using at least one pyrotechnic actuator which provides speed and power for positioning.

on détermine, à partir de la vitesse et de la direction de la menace, les angles de sites et de gisement à donner au tube de lancement de la munition de défense ainsi que l'instant auquel cette munition doit être éjectée hors du tube suivant cette direction,

on déclenche en séquence les moyens de positionnement du tube puis le tir de la munition,

on commande, avant ou après les moyens de positionnement, des moyens assurant le freinage et/ou l'arrêt des moyens de positionnement lorsqu'ils ont orienté le système de tir suivant les angles souhaités.

Thus, the subject of the invention is a method of defending a vehicle or a structure against a threat such as a projectile, method using site positioning and / or deposit means of at least one launching tube defense ammunition, means which comprise at least one pyrotechnic jack, process in which the speed and direction of the threat are determined by means of measurement and calculation, process characterized by the following steps:

we determine, from the speed and direction of the threat, the angles of sites and bearing to be given to the launch tube of the defense ammunition as well as the instant at which this ammunition must be ejected out of the tube following this direction,

the tube positioning means are triggered in sequence, followed by firing of the ammunition,

command, before or after the positioning means, means ensuring the braking and / or stopping of the positioning means when they have oriented the firing system at the desired angles.

According to a particular embodiment, at least one positioning means is a double pyrotechnic cylinder effect incorporating two pyrotechnic charges having an effect antagonist each connected to a separate room, both chambers being separated by a movable piston, the process is then characterized in that, to ensure braking at least minus a positioning means, we order successively in sequence the two pyrotechnic charges of the cylinder considered so as to ensure by the action of the second loads a braking movement of the piston which has been controlled by the first charge, the time interval between the initiation of each charge being chosen so as to ensure the desired positioning for the piston.

According to a variant of the process, the pressure in the first chamber in which the first charge is initiated, we will compare this pressure to a value theoretical memorized then we will correct the time interval before initiation of the second charge and / or we will open a vent in at least one of the bedrooms so as to take account the difference observed between the theoretical pressure and the pressure measured.

So when the pressure measured in the first chamber is lower than the theoretical pressure stored on may delay the initiation time of the second charge and / or we can open a vent in the second bedroom.

Conversely, when the pressure measured in the first chamber is greater than the theoretical pressure stored on can anticipate the moment of initiation of the second charge and / or we can open a vent in the first bedroom.

We can also determine the actual position of the piston and use this measurement to correct the instant initiating the second charge and / or opening a vent in either room.

The invention also relates to a device for defense using such a method.

This device allows the defense of a vehicle or a structure against a threat like a projectile. He understands means of positioning on site and / or at least minus a tube for launching a defense ammunition, means positioning systems which include at least one cylinder pyrotechnic, device also comprising means for detection of projectile approach and calculation means to determine the angles of elevation and bearing at give the defense ammo launch tube as well that the time at which the ammunition is to be ejected from the tube in the direction of fire, device characterized by what it includes electronic control means ensuring a sequence initiation of the actuator (s) positioning pyrotechnics and firing of the ammunition, as well as means ensuring braking and / or stopping of positioning means when they have oriented the shot at the desired angles.

According to a particular embodiment, the means of braking and / or stopping of the positioning means are formed by deployable abutment surfaces integral with the body of the pyrotechnic cylinder (s), the deployment of abutment surfaces being controlled by electronic means control.

Advantageously, the device is characterized in that defense ammunition has an efficiency zone spatial at a nominal working distance, and in that two consecutive abutment surfaces carried by a cylinder body are separated by a distance which determines a difference of angular positioning for the tube ensuring recovery of the effectiveness zones of the defense ammunition for the two consecutive directions and at said distance nominal use.

According to another embodiment, one of the means of site and / or deposit positioning includes at least one double acting pyrotechnic cylinder incorporating two charges antagonistic pyrotechnics each linked to a separate bedroom, the two bedrooms being separated by a movable piston, and the electronic control means ensure a sequence initiation of the two charges pyrotechnics of the cylinder considered with a time interval chosen so as to ensure the braking of the piston and the desired positioning in site and / or deposit.

According to an alternative embodiment the device defense may include means to measure the pressure in the two chambers of one of the cylinders pyrotechnics, these means being connected to the means control electronics, which can compare the pressure measured in a first chamber with at least one theoretical value so as to correct the time interval before initiation of the second load of the jack in question.

Advantageously, the device may include means for determining the actual position of the piston of the pyrotechnic cylinder or the positioning on site or in deposit given by this jack, these means being connected to electronic control means.

According to another variant of the invention, the device may include at least one vent for each room, vent the opening of which can be ordered by the means control electronics and will allow to set communicating said room with the outside.

• la figure 1 est un schéma en vue de dessus représentant l'engagement par un dispositif selon l'invention d'un projectile menaçant un véhicule,
• la figure 2 est un logigramme montrant la succession des étapes dans un premier mode de réalisation d'un dispositif de défense selon l'invention,
• la figure 3 est une vue en coupe d'un mode de réalisation d'un actionneur pyrotechnique mis en oeuvre dans un dispositif de défense selon l'invention,
• les figures 4a et 4b sont des coupes transversales de cet actionneur, coupes réalisées au niveau d'un moyen d'arrêt suivant le plan dont la trace AA est représentée à la figure 3, la figure 4a montre le moyen d'arrêt au repos et la figure 4b à l'état activé,
• la figure 5 est analogue à la figure 1 et montre le recouvrement des zones d'efficacité pour deux positions successives de l'actionneur en gisement.
• les figures 6a et 6b sont des vues en coupe d'un autre mode de réalisation d'un actionneur pyrotechnique mis en oeuvre dans un dispositif de défense selon l'invention, la figure 6a montrant un moyen d'arrêt au repos et la figure 6b un moyen d'arrêt activé.
• la figure 7 est une vue schématique en coupe d'un dispositif de défense selon l'invention,
• la figure 8 est une vue schématique en coupe d'un autre mode de réalisation d'un dispositif de défense selon l'invention,
• la figure 9 est une vue en coupe longitudinale d'un autre mode de réalisation d'un vérin pyrotechnique mis en oeuvre dans un dispositif de défense selon l'invention,
• la figure 10 est un exemple de courbes représentant l'évolution des pressions dans les chambres d'un tel vérin ainsi que la course de vérin obtenue,
• la figure 11 est un exemple de courbe montrant l'intervalle de temps entre l'initiation de deux générateurs pyrotechniques d'un vérin en fonction de la course souhaitée,
• la figure 12 est une vue en coupe d'un autre mode de réalisation d'un vérin mis en oeuvre dans un dispositif de défense selon l'invention,
• la figure 13 est un logigramme montrant la succession des étapes dans un dispositif de défense selon un deuxième mode de réalisation de l'invention.

The electronic control means may cause the munition to fire at an instant such that it leaves the tube substantially at the instant when the angles of elevation and bearing are obtained. The invention will be better understood on reading the description which follows of different embodiments, description made with reference to the appended drawings and in which:

• FIG. 1 is a diagram in top view representing the engagement by a device according to the invention of a projectile threatening a vehicle,
• FIG. 2 is a flow diagram showing the succession of steps in a first embodiment of a defense device according to the invention,
• FIG. 3 is a sectional view of an embodiment of a pyrotechnic actuator used in a defense device according to the invention,
• FIGS. 4a and 4b are transverse sections of this actuator, sections made at the level of a stop means along the plane, the trace AA of which is shown in FIG. 3, FIG. 4a shows the stop means at rest and FIG. 4b in the activated state,
• FIG. 5 is analogous to FIG. 1 and shows the overlap of the efficiency zones for two successive positions of the actuator in bearing.
• Figures 6a and 6b are sectional views of another embodiment of a pyrotechnic actuator used in a defense device according to the invention, Figure 6a showing a stop means at rest and Figure 6b an activated stop means.
• FIG. 7 is a schematic sectional view of a defense device according to the invention,
• FIG. 8 is a schematic sectional view of another embodiment of a defense device according to the invention,
• FIG. 9 is a view in longitudinal section of another embodiment of a pyrotechnic jack used in a defense device according to the invention,
• FIG. 10 is an example of curves representing the evolution of the pressures in the chambers of such a jack as well as the stroke of the jack obtained,
• FIG. 11 is an example of a curve showing the time interval between the initiation of two pyrotechnic generators of a jack as a function of the desired stroke,
• FIG. 12 is a sectional view of another embodiment of a jack used in a defense device according to the invention,
• FIG. 13 is a flow diagram showing the succession of steps in a defense device according to a second embodiment of the invention.

Figure 1 shows a top view of a vehicle 1 such as a battle tank which takes to the level of its glacis before a defense device 2 according to the invention. These measures includes a small turret 3 which carries a tube 4 allowing firing a defense ammunition.

This tube 4 is adjustable in site and in deposit. The angle α shown in the figure between the direction δ of the axis of the tube 4 and a vertical plane P is the bearing angle. This angle is obtained by a rotation of the turret 3 by relative to vehicle 1.

The elevation angle is not shown here. This angle is the one made by the direction δ of the tube 4 with a plane horizontal.

The positioning in site and in deposit is obtained by pyrotechnic cylinders (not visible in this figure).

Device 2 makes it possible to defend vehicle 1 against a threat which is a projectile 6 (missile or rocket). We here represented two successive positions of the projectile marked 6a and 6b.

The vehicle includes means of measurement and calculation to determine the speed V and the direction Threat Δ 6.

These means comprise a firing line 9 associated by example to a tracking radar 7 which is carried by the turret 8 of vehicle 1.

In a classic way and taking into account the characteristics of defense ammunition, fire control determines in space the direction δ which is the optimal direction of fire of this ammunition 5 so that it can counter threat 6.

Ammunition 5 could be an ammunition generating a sheaf of shards (focused according to a sector or not) or else ammunition generating a blast effect.

This munition has an efficiency volume E which is here shown with a substantially elliptical shape. This volume is the one within which the probability of destruction and / or destabilization of threat 6 by the ammunition 5 is equal to 1.

The fire control also calculates the instant at which this ammunition must be ejected from the tube 4 according to this direction δ. This instant is calculated from the speed V of the projectile 6 detected and of the speed v (known) of the Defense ammunition 5. It is also calculated by taking account for the volume of efficiency and the fact that the interception must intervene at the level of an interception sphere SI centered on defense turret 3 and radius R. This radius is attached to the system design so as to minimize effects on vehicle 1 (this sphere has a radius included between 5 and 10 m).

The optimal direction δ is therefore that which allows to include projectile / threat 6 in the effectiveness volume E of defense ammunition 5 when this projectile arrives at level of the SI interception sphere.

The fire control therefore determines the angles of the sites and of deposit to be given to the launch tube 4 of the ammunition defense so that the axis of this one is confused with the direction δ.

Knowledge of the instant (T _R ) at which the defense ammunition 5 must be ejected from the tube 4 and that of the dynamic characteristics of the positioning means in elevation and / or deposit (inertia of the moving parts of the turret 3, accelerations communicated by the actuators, response time of the initiation means of the pyrotechnic actuators) make it possible to determine a first instant (T _G and / or T _S ) at which the positioning means or means in site (instant T _S ) or in deposit (instant T _G ) must be ordered.

Furthermore, knowledge of the instant (T _R ) at which the defense ammunition 5 must be ejected from the tube 4 makes it possible to determine a second instant (T _T ) at which the propellant charge of the ammunition 5 must be ignited. This data is specific to the defense system developed and it depends on the characteristics of the propellant means (pressure and speed communicated to the munition, response time of the means of ignition of the propellant charge).

The flow diagram in Figure 2 shows the succession of steps of the method according to a first embodiment of the invention.

Block C1 corresponds to the supply by the firing line of instructions for positioning the tube in elevation (S) and in deposit (G) as well as the instant (T _R ) at which the ammunition must leave the launching tube to counter threat 6 at the level of the SI interception sphere.

An electronic control means integrated into the defense device (or the firing line) then calculates (block C2) the instant (T _T ) at which the firing of the ammunition must be controlled so that its exit from the tube occurs at the instant T _R. This instant corresponds to the moment of exit of the ammunition 5 (T _R ) minus the stage of ignition of the propellant charge thereof and the stage of ballistics inside the munition in the tube 4.

The control means also calculates (block C3) the initiation instant (T _S ) of the pyrotechnic charge of the site positioning cylinder.

It also calculates (block C4) the instant of initiation (T _G ) of the pyrotechnic charge of the position positioning cylinder. All calculations will be performed simultaneously.

The control means then sequentially causes the different initiations of the pyrotechnic charges of cylinders as well as the shot following the time sequence as well calculated.

Block A1: triggering of positioning in deposit (T _G ), block A2 triggering of positioning in site (T _S ), block A3 triggering of firing (T _T ). The relative order of triggers A1 and A2 will depend on the set angles given on site and in deposit.

In FIG. 2, it is considered that the order relating to the positioning of the deposit occurs first. It is of course the longest rally which is triggered first. The objective is to rally on site and in simultaneous deposit at time T _R.

Line L represents the simultaneity at the planned time T _R of the positions in elevation, in deposit and of the exit of the ammunition out of the tube.

Thus the ammunition 5 leaves the launch tube 4 when positioning means oriented the firing system at the desired angles.

The method according to the invention thus provides a simple sequential triggering of the positioning means of the tube and then firing the ammunition.

Furthermore, means ensuring braking and / or stopping of the positioning means will be ordered when they have oriented the firing system at the desired angles. The blocks A4 and A5 symbolize these commands F _G (braking / stopping the positioning in the field) and FS (braking / stopping the positioning in the site).

This minimizes the mechanical disturbances brought to the ammunition 5 by the movements of the launch tube 4.

The positioning means use one or more several actuators or pyrotechnic cylinders. These actuators as described by FR2809172 include a piston which slides in a cylinder. The displacement of the piston is caused by gases of a pyrotechnic composition, such a propellant powder.

To control the braking of such an actuator pyrotechnic one could for example cause a deformation cylinder, deformation preventing the piston from exceed a certain point.

Depending on the structure of the braking / stopping means used, we can order these means at the same time as positioning means or after.

Figures 3,4a, 4b show an exemplary embodiment a double-acting linear pyrotechnic actuator 10 (pyrotechnic cylinder) incorporating means ensuring stopping of the actuator, means which will advantageously be controlled before or at the same time as the positioning means.

This actuator comprises a cylindrical case 11 of axis 13 which is closed at each end by a cover 12a, 12b. This case contains five rings 14a, 14b, 14c, 14d and 14e which delimit a cylindrical internal housing 15 divided in two chambers 16a and 16b by a piston 17 secured to a rod 18.

The case 11 and the rings 14 form the body of the jack. The rings make it possible to position and wedge means of braking / stopping 23a, 23b, 23c and 23d. The case 11 ensures the cohesion of the cylinder body.

The piston is shown here in the initial position of the cylinder, position in which the rod 18 is made integral cylinder by a shearable radial pin 19 arranged between the rod 18 and the cover 12b.

Gas sealing means, such as seals annulars not shown, are interposed between the piston 17 and housing 15.

Each chamber 16a, 16b can be pressurized by a gas-generating pyrotechnic charge 20a, 20b. These charges are arranged at the covers 12a, 12b which provide the closure of the case 11, covers which are crossed by rod 18. Gas seals are provided between the covers and the rod 18.

The pyrotechnic charges 20a, 20b consist of example by 2 to 3 grams of simple basic propellant powder. Each composition can be initiated by an igniter (not shown) which is connected by conductors 21a, 21b to electronic control means 22.

The initiation of charge 20a will cause the rupture of the pin 19 and the displacement of the piston 17 in the direction D2 until it stops against the cover 12b.

Alternatively, the initiation of charge 20b causes it also the rupture of the pin 19 and the displacement of the piston 17 in direction D1 until it stops against the cover 12a.

In accordance with the invention, this actuator incorporates means braking and / or stopping of its piston which are formed by deployable abutment surfaces 23a, 23b, 23c and 23d integral with the cylinder body. These stop surfaces are more particularly visible in Figure 4a. They include two portions of circular washers 24 and 25 which are housed in a cylindrical groove 26 arranged between two consecutive rings 14c and 14d.

These washer portions are fixed at their ends with two piezoelectric actuators 27, 28. The actuators 27, 28 of each stop 23 are connected in pairs to the means control electronics 22. A housing (not shown) shared between each ring 14 makes it possible to receive each actuator 27 or 28. The actuators are chosen in such a way so that when they are supplied with electric current they shorten and bring the two portions of washer 25, 25 of the axis 13 of the cylinder body.

When the braking means is at rest (Figure 4a) the washer portions 24 and 25 are completely inside of groove 26 and they do not hinder the passage of the piston 17 in housing 15.

When the braking means is activated (Figure 4b) the washer portions 24 and 25 come out of the housing 15 and protrude inside of it. They then form an abutment surface which stops the jack 17 at level of the groove 26 considered.

The washers have a thickness of about 3 mm they are dimensioned radially so that they are, in the activated position, in contact with the groove 26 with sufficient contact surface to ensure stopping piston.

The radial stroke of the washers is of the order of millimeter and actuator response time known piezoelectric allows the deployment of washers before the cylinder has traveled the stroke that separates from the washer.

The example shown in Figure 3 includes four means braking. The cylinder thus comprises (with the position center and the two stop positions against the covers) seven different positions for its stem and can therefore quickly and reliably position the tube on site or deposit at seven different angles. It is understood possible to define a cylinder with a number of means different braking.

When the fire control has determined the angles of elevation and of deposit to be rallied by the defense system, it immediately controls the positioning of the braking ensuring the desired angle (or the nearest angle the desired angle).

Advantageously, the positioning jacks will be defined. so that two consecutive stop surfaces carried by the cylinder body are separated by a distance which determines for the tube 4 a difference of angular positioning ensuring overlap of the zones Defense ammunition efficiency 5.

As is more particularly visible in the figure 5, the jack (not shown) ensuring the positioning in tube 4 deposit has two stop positions consecutive determining the directions δ1 and δ2 which make the angles α1 and α2 respectively with the plane P. These directions are close enough to each other to that, at the level of the interception sphere SI, the zones E1 and E2 overlap.

So for any threat approach direction bringing this one between the directions δ1 and δ2, we are assured of optimal destruction or disruption of the threat.

The fire control team can then choose for example the direction δ2 if the theoretical direction calculated for the pointing of tube 4 is between δ1 and δ2.

The stop positions for the positioning cylinder in site are defined in a similar way.

In all cases, we are thus guaranteed to obtain a effective defense regardless of the angle of attack even if the number of possible pointing positions is limited.

Figures 6a and 6b show another mode of realization of a positioning cylinder according to the invention.

This mode differs from the previous one in that the jack 10 allows directly control a rotary movement.

For this purpose the piston 17 is in the form of a flap which is integral with an axis 29 capable of a movement of rotation relative to the body 30 of the jack. One end of the flap 17 which carries a seal 48 is in contact with an internal cylindrical wall 31 of the body 30 (see Figure 6b). A shear pin 32 is interposed between axis 29 and body 30. It secures the flap 17 and the body 30 in the rest position of the jack.

The axis 29 crosses the body 30 and it is pivotally mounted relative to the body on bearings (not shown).

The body 30 defines an internal housing which has the form of a cylindrical sector of axis coincident with that of the axis turning 29.

In its rest position, the flap 17 is in a middle position which separates the housing from the body 30 in two chambers 16a, 16b of substantially equal volume and having each in the form of a cylindrical sector.

The body also carries two pyrotechnic charges 20a and 20b, each load being connected to one of the chambers 16a, 16b.

Depending on the charge 20a or 20b which is initiated by the electronic control means 22 the flap 17 moves in either direction (R1 or R2). This embodiment therefore makes it possible to control a pivoting of the axis 29 which is between -90 ° and + 90 ° relative to a position median initial of the flap.

It is of course possible to give part 17 a initial position which is not the middle position. A such an arrangement will give the jack 10 a angular positioning capacity which will be greater in one direction of rotation than in the other.

The initial volumes of the two chambers 16a and 16b will be so different. We can therefore in this case provide different pyrotechnic charges for both cylinder chamber, for example composition masses different pyrotechnics.

When a charge 20a or 20b is initiated, the pressure gases increase strongly in volume 16a or 16b. The pin 32 is sheared and the flap moves in the direction R1 or R2.

The flap drives the axis 29. The rotation can thus be between -90 ° and + 90 °.

This cylinder carries means for braking and / or stopping its flap 17 which are formed by abutment surfaces deployable 23a, 23b, 23c and 23d secured to the body 30 of the cylinder.

Each abutment surface includes a corner 33 mounted pivoting with respect to an axis 34 integral with the body 30.

The corner extends over the entire height of the chamber 16a or 16b. It can pivot by the action of an actuator piezoelectric 35, incorporated in the wall 30 of the jack, and which is connected to the electronic control means 22 by a link 36.

Figure 6a shows all the stop surfaces in their rest position.

In this position they are not protruding by relative to the internal surface 31 of the body 30 and do not interfere moving the flap 17.

Figure 6b shows the corner 33 of the stop 23a in deployed position. Driven by piezoelectric actuator 35 the corner is protruding from the internal surface 31 of the body and stops the shutter 17.

The contact surface of each stopper will be chosen sufficient to stop the shutter. It is enough for that to give the corner 33 a height of the order of 1 to 2 mm.

As in the previous embodiment, we can provide a different number of stop surfaces.

A number of abutment surfaces will preferably be adopted such that two consecutive stop positions determine directions close enough to each other that at level of the SI interception sphere, the efficiency zones Defense munitions E1 and E2 overlap for two directions δ1, δ2 of the axis of the tube 4 (see Figure 5).

Figure 7 shows a first example of a turret 3 of launch of a defense ammunition 5. This turret comprises a turntable 37 which is integral with an axis vertical 29 and can therefore pivot relative to a support fixed 38 which is for example linked to a vehicle (not represented).

The pivoting of the axis 29 is done by bearings 41. This pivoting of the plate ensures positioning in deposit of tube 4.

The plate 37 carries the tube 4 which is integral with a base 40 which can pivot relative to the plate 37 around an axis 39.

The axis 29 is integral with a flap 17b of a pivoting jack 10b as described above with reference to the figures 6a, 6b. The body 30 of the jack is also made integral of the support 38 by a connecting means (not shown) such screws or fixing lugs. The cylinder 10b ensures the positioning of the launcher tube 4 in relation to the support 38.

Furthermore, the tube 4 can pivot relative to the plate 37 around the axis 39 which is perpendicular to the axis vertical 29.

A linear pyrotechnic cylinder 10a as described previously with reference to Figures 3 and 4 is mounted from articulated between the plate 37 and the base 40.

The cylinder body is articulated on a lug 42 integral of the plate 37. The end of the rod 18 of the jack is articulated on another tab 43, integral with the base 40.

The jack 10a makes it possible to control the positioning in site of the tube 4 relative to the plate 37 and to the support 38.

This cylinder is double acting. It has two charges pyrotechnics 20a and 20b, connected to electronic means 22, and which control the output of the rod 18 or else its entry into the jack body. The pointing can thus be achieved with elevation angles positive or negative.

Ammunition 5 is expelled from tube 4 by a charge propellant 44 which is ignited by an igniter 45. This last is initiated by a contact 46 which is connected by a wired connection not shown by electronic means control 22 which are here housed in the support 38.

The tube 4 is here represented as a tube closed at its rear part and the load 44 expels the ammunition from the tube by canon effect. It is of course possible to plan a propellant charge in the form of a solid propellant ammunition. In this case the tube 4 will be open to its part which will reduce the recoil suffered by the support 38.

The electronic control means 22 ensure the firing defense ammunition as well as the initiation of different pyrotechnic charges of the cylinders 10a and 10b. They also ensure the deployment of the braking means and / or stop piston of each cylinder.

According to the embodiments previously described, the braking means will preferably be deployed from the determination of the desired site and site angles.

The initiation of the pyrotechnic charges of the different cylinders will however be initiated following a sequence of functioning such as positioning in site and in deposit occur substantially at the same time.

This operation has been described previously with reference in Figure 2.

Figure 8 differs from Figure 7 in that the cylinder linear 10a is replaced by a second pivoting jack 10c. The body 30c of this jack is integral with a stirrup 47 secured to the end of the vertical axis 29 while the flap 17c of this jack is integral with axis 39. This axis is secured to the base 40 carrying the tube 4. Thus the second cylinder 10c ensures the site positioning of the tube 4.

This embodiment allows with two cylinders to identical structure and compact to ensure a pivoting system site and bearing along deflection angles important (greater than 90 °). The response time is very weak (of the order of one hundred milliseconds) and the energy developed by the pyrotechnic compositions is sufficient to drive the moving parts and heavy in the desired timeframe (mass of the order of 50 kg).

As a variant, it is possible to define cylinders linear or rotary and in which the braking means or blocking will be deployed after initiation of the charge pyrotechnic cylinder.

We can thus design a cylinder in which the means brake will be integrated into the piston or flap body mobile. This braking means could for example be consisting of a pad between piston and cylinder body, pad which will be deployable by a piezoelectric actuator or by a pyrotechnic initiator.

It will also be possible to brake the actuator by a deferred initiation of the second pyrotechnic charge of the cylinder considered. The back pressure generated by this second charge will brake the cylinder piston. The time interval between the initiation of the first and the second load of a given cylinder will modify the maximum stroke obtained with this cylinder.

We can then advantageously provide means to check the actual position of the piston.

These means will include for example measuring means the actual position of the piston and / or the measuring means of the actual gas pressure in the chambers. Ways control electronics will then incorporate a rustic enslavement using this information from position of the piston and / or pressure in the chambers for correct the positioning of the piston.

To correct (to some extent) the position real piston it is possible to modify the interval of time separating the initiation of the two charges. We can also change the pressures in the rooms by opening or closing vents allowing each room to communicate piston with the outside.

This second embodiment of the device and the process according to the invention will be described with reference to Figures 9 to 13.

FIG. 9 thus shows an exemplary embodiment of a actuator or pyrotechnic cylinder 10 incorporating such a means pyrotechnic braking.

This cylinder allows direct movement control rotary. For this purpose it includes a piston which has the form a flap 17 secured to an axis 29 capable of rotational movement relative to a body 30.

One end of the flap 17 which carries a seal 48 is in contact with an internal cylindrical wall 31 of the body 30. A shear pin 32 is interposed between axis 29 and body 30. It secures the flap 17 and the body 30 in the rest position of the jack.

The axis 29 crosses the body 30 and it is pivotally mounted relative to the body on bearings (not shown).

The body 30 defines an internal housing which has the form of a cylindrical sector of axis coincident with that of the axis turning 29.

In its rest position, the flap 17 is in a middle position which separates the housing from the body 30 in two chambers 16a, 16b of substantially equal volume and having each in the form of a cylindrical sector.

The body also carries two pyrotechnic charges 20a and 20b, each load is connected to one of the chambers 16a, 16b and allows to pressurize it.

The pyrotechnic charges 20a, 20b consist of example by a gas-generating composition, such as 2 to 3 grams of a simple basic propellant powder. Each composition can be initiated by an inflammator (not shown) which is connected by conductors 21a, 21b to electronic control means 22.

Depending on the charge 20a or 20b which is initiated by a electronic ignition device, incorporated in the means control electronics 22, the flap 17 moves in either direction (R1 or R2). This actuator therefore allows to control a pivoting of the axis 29 which is between - 90 ° and + 90 ° relative to a median initial position of the shutter.

The initiation of charge 20a causes the rupture of the pin 32 and the rotation of the flap 17 in the direction R2 until it comes into abutment against the body 30.

Alternatively, the initiation of charge 20b causes it also the rupture of the pin 32 and the rotation of the flap 17 in direction R1 until it abuts against the body 30.

In accordance with the invention, the electronic means of control 22 incorporate a computer 120 as well as at least a memory or register 130.

This memory contains curves in digital form characteristics giving the theoretical pressure in each room as a function of time.

The computer 120 is programmed so that it can initiate in sequence the two pyrotechnic charges 20a and 20b.

When a second charge is thus initiated (for example example 20b) after the initiation of a first charge (20a), a back pressure appears in the second chamber 16b after the appearance of pressure in the first chamber 16a.

This back pressure causes braking of the displacement of part 17.

In the simple case described here where the charges pyrotechnics 20a, 20b used are identical for each room and where the initial volumes of rooms 16a, 16b are also equal, the flap 17 will be positioned at the end of a some time at its initial median position. In effect this position corresponds to the balance between pressures in both rooms.

Before reaching this equilibrium position the speed flap rotation will decrease and then change direction. he there is therefore a position of the flap for which the speed of this one is canceled. This position will depend on the interval of time separating the initiation of the two charges pyrotechnics 20a and 20b.

If this time interval is short, the stroke of the flap will be reduced.

If this time interval is important the stroke of the flap will approach the maximum possible travel.

So it is possible by playing on the time interval separating the initiations of the two charges to give to the flap 17 a well defined stroke or pivot angle.

Those skilled in the art will easily establish the abacuses which, for a given cylinder configuration (composition and mass of pyrotechnic charges, shutter inertia as well as mechanism driven by it ...), will define the stroke obtained as a function of the time interval separating each initiation.

These charts will be introduced into memory 130 or in a register of the computer 120. The latter will order then the appropriate initiation sequence in response to a instruction provided by a user or by a system or control automaton (for example through an interface 140 or a fire line for a vehicle defense application).

P1 qui donne l'évolution de la pression en fonction du temps dans la première chambre où la charge pyrotechnique est initiée (pression en Méga Pascals),

P2 qui donne l'évolution de la pression en fonction du temps dans la deuxième chambre où la charge pyrotechnique est initiée (pression en Méga Pascals),

C qui donne le débattement angulaire du volet 17 en fonction du temps (angle en degrés).

For example, for a rotary actuator having a total volume of the chambers of 450 cm3, and allowing a pivoting of +/- 90 ° relative to the initial position, each pyrotechnic charge being made up of 3 grams of simple base powder, Figure 10 shows the curves:

P1 which gives the evolution of the pressure as a function of time in the first chamber where the pyrotechnic charge is initiated (pressure in Mega Pascals),

P2 which gives the evolution of the pressure as a function of time in the second chamber where the pyrotechnic charge is initiated (pressure in Mega Pascals),

C which gives the angular movement of the flap 17 as a function of time (angle in degrees).

The pyrotechnic charge of the second chamber is here initiated 20 milliseconds after the first charge. It results in a maximum travel of 90 ° which occurs at the end time t = about 40 milliseconds.

Figure 11 is an abacus which gives for this cylinder the value of the interval to be programmed between each initiation depending on the maximum angular travel desired.

It is of course possible to initiate only one charge. We then obtain in a conventional way the travel maximum possible (flap in abutment against the body 30).

It is of course possible to give part 17 a initial position which is not the middle position. A such an arrangement will give the jack 10 a angular positioning capacity which will be greater in one direction of rotation than in the other.

The initial volumes of the two chambers 16a and 16b will be so different. We can therefore in this case provide different pyrotechnic charges for both cylinder chamber, for example composition masses different pyrotechnics.

Figure 12 shows another embodiment of a pyrotechnic actuator 10 with pyrotechnic braking. This actuator is produced here in the form of a linear cylinder double acting with a cylindrical body 30 with axis 13 delimiting a cylindrical internal housing divided in two chambers 16a, 16b by a piston 17 secured to a rod 18.

The piston is shown here in the initial position of the cylinder, position in which the piston is secured of the body 30 by a radial shear pin 19 interposed between the rod 18 and an end cover 12a. Gas sealing means such as non-annular seals shown are provided between the piston and the body.

Each chamber 16a, 16b can be pressurized by a gas-generating pyrotechnic charge 20a, 20b. These charges are arranged at the covers 12a, 12b ensuring the closing of the body 30, covers which are crossed by the rod 18. Gas seals are provided between the covers and the rod 18.

The initiation of charge 20a causes the rupture of the pin 19 and the displacement of the piston 17 in the direction D2 until it stops against the cover 12b.

Alternatively, the initiation of charge 20b causes it also the rupture of the pin 19 and the displacement of the piston 17 in direction D1 until it stops against the cover 12a.

Again and in accordance with the invention the means control electronics 22 incorporate a computer 120 as well as at least one memory or register 130,, and the computer 120 is programmed so that it can initiate sequence the two pyrotechnic charges 20a and 20b.

This initiation in sequence slows down the displacement of the piston 17.

This one will position itself after a certain time at level of its initial median position which corresponds in the example described here at the balance between pressures in the two bedrooms.

Before reaching this equilibrium position the speed of the piston will decrease and then change direction. So there is a position of the piston for which the speed of the latter cancels. This position will depend on the time interval separating the initiation of the two pyrotechnic charges 20a and 20b.

If this time interval is short, the stroke of the piston will be reduced.

If this time interval is important the stroke of the piston will approach the maximum possible stroke.

So it is possible by playing on the time interval separating the initiations of the two charges to give the piston 5 a well defined maximum stroke.

Again, it will suffice for those skilled in the art to establish the charts which, for a given cylinder configuration (composition and mass of pyrotechnic charges, inertia of the piston, rod as well as the mechanism driven by the rod ...), will define the stroke obtained as a function the time interval between each initiation.

The actuators shown in Figures 9 and 12 also include means for measuring the pressure in the two chambers 16a and 16b. These means are constituted by pressure probes 150a, 150b.

The probes 150a, 150b are connected to the electronics of control 22 by links 160a, 160b.

In the embodiment of FIG. 9, the probes are shown fixed radially in the wall cylindrical body 30. They could of course be carried by a bottom wall of the body or by a wall from above (not shown). In the embodiment of FIG. 12, the probes are fixed to the covers 12a and 12b.

Thus the control electronics 22 can control the actual pressure in each of the chambers 16a, 16b and she can compare this pressure to a theoretical value which is in memory.

It is then possible to correct the time interval before the initiation of the second charge so as to hold account of the pressure difference thus measured.

Indeed dispersions can occur at the level of real pressures, dispersions linked for example to the variation of the characteristics of the different loads pyrotechnics of a production batch, or linked to operating conditions (temperature, pressure atmospheric).

If these dispersions were not taken into account, would result in a difference between the positioning setpoint of the cylinder rod and the position actually observed.

Those skilled in the art will easily establish abacuses of correction allowing, for a given cylinder geometry and as a function of a pressure difference measured in the first room, determine the advance or delay to be made to the instant of initiation of the second charge.

When the pressure measured in the first chamber is lower than the memorized theoretical pressure so we delay the instant of initiation of the second charge.

Conversely when the pressure measured in the first chamber is greater than the theoretical pressure stored on anticipates the initiation time of the second charge.

We thus realize a rustic control providing a only correction but which is sufficient if the values of dispersions remain small.

In certain cases and in particular if the dispersions are too large (greater than 5% in absolute value) it will be necessary to provide other means to regulate the pressure level in chambers 16a and 16b.

We can as Figures 9 and 12 also show provide at least one vent 170a, 170b in each room. These vents allow to connect the room (16a or 16b) with the outside of the cylinder body.

The vents shown in Figure 9 are carried by the bottom wall of the body 30. The vents represented in the figure 12 are fixed radially to the cylindrical body 30.

The opening of the vents 170a, 170b is caused by the electronic control means 22 to which they belong connected by links 180a, 180b.

The vents will be produced for example in the form of normally closed small valves with a stem which ensures the closure of the valve and which is integral with a electro magnet.

When the pressure measured in the first chamber is higher than the memorized theoretical pressure we can then order the opening of the vent connected to the first bedroom. This will reduce the value of the pressure in the first chamber so as to bring it substantially to the theoretical value. The vent can then be closed.

Conversely when the pressure measured in the first chamber is lower than the theoretical pressure stored on may order the opening of the vent connected to the second bedroom.

This variant of the invention makes it possible to provide successively several corrections to the pressures in the different rooms.

We can of course combine a correction at the level the initiation interval between charges and a pressure regulation through the vent (s).

This embodiment thus ensures a enslavement to overcome all the dispersions of the device (dispersion on the pressures in the two rooms but also on the delays between the initiations).

To perfect this enslavement we can also provide means for determining the position of the piston or flap. Such means are well known. They can be integrated into the cylinder or carried by the structure actuated by the jack. We could for example use an optical encoder carried by the rotary axis 29 for a rotary actuator as shown in Figure 9. We can for a linear cylinder as shown in Figure 12 use an optical position sensor to identify the end of the cylinder rod.

The electronic control means will use the information relating to the actual position of the cylinder for order for example the vents and / or modify the interval of initiation between charges.

Alternatively we can replace the pin locking 19 of the piston or flap by a device reversible, for example a latch pushed by a spring and coming to rest on a flat. Such a solution allows make a pyrotechnic cylinder that can be reused several times. For a new use, it will suffice to reposition the flap or piston to its initial position locked and replace the pyrotechnic charge (s) gas generators that have been used.

Different variants are possible without leaving the frame of the invention. We could thus define a linear cylinder the piston of which is not at rest in position median but would be positioned more or less close to one of the end covers. The initial volumes of the two rooms would then be different.

We could also define a cylinder in which the pyrotechnic charges would be different for each bedroom.

In all cases, the skilled person will establish during the cylinder design the abacuses necessary to allow the control of the desired positioning.

The actuators according to the invention can be used in different applications for which it is necessary to give a very rapid amplitude movement given.

The actuator according to the invention does not by itself allow maintain an organ in a given position. This maintenance may however be ensured by means classics not shown and attached to the ordered organ by the jack (for example a locking pawl).

According to the invention this actuator is particularly well suited to the implementation of a defense system of a vehicle or structure against a threat such as projectile.

Indeed it is necessary for such an application to ensure the positioning on site and / or at least of minus one ammunition launch tube in an interval very short time (of the order of a few tens of milliseconds).

The pyrotechnic energy used in the cylinders is sufficient to ensure the displacement of inertias mechanical of such defense devices. The cylinders pyrotechnics also ensure the speed of positioning required.

The method according to this second embodiment of the invention also ensures the accuracy of the site and deposit positioning despite the absence of mechanical stop corresponding to the desired positioning.

This stop is not necessary because it suffices to ensure expelling the ammunition from the tube when the latter is is oriented in the desired direction. Indeed, the desired position is that at which the cylinder speed is practically zero.

The electronic control device 22 may be programmed to trigger this shot moments before the arrival of the tube at the angular positioning in elevation and in correct deposit. The trigger is triggered before arrival at the position because the pressurization of the load propellant of defense ammunition and its course in the tube last a while (around 30 milliseconds). It is therefore necessary to anticipate in order to ensure that the ammunition leaves the tube according to the good direction and with the least lateral disturbance possible (cylinder positioning speed substantially nothing).

As shown for example in Figure 10, this speed changes very slightly over a range of approximately 8 milliseconds around the positioning value desired. When the ammunition comes out of the tube in this position it is practically not disturbed by tube movements.

Actuators with pyrotechnic braking may be used in turrets similar to those described previously with reference to Figures 7 and 8.

As described above, these turrets are intended for the defense of a vehicle or a structure against a missile or rocket attack. It is essential that such a turret can ensure a rapid and reliable positioning of the tube 4 according to a direction determined upon detection of the threat by fire control.

The positioning time is generally around the hundred milliseconds.

With cylinders with pyrotechnic braking, both pyrotechnic charges of each cylinder will be initiated in sequence as a result of the site and time setting instructions deposit provided by the firing line (not shown) which is connected to the control means 22 which it controls the operation. Of course the fire control and the electronic control means 22 may form a single together.

Thus the control means will brake the pistons of the cylinders so that the speed of these pistons to be substantially zero for pointing values desired and communicated by the fire control.

Furthermore, the electronic control means 22 initiate the operating sequence of a cylinder by relative to each other so that the positioning in site and deposit occur more or less the same moment.

The flow diagram in Figure 13 is similar to that described previously with reference to FIG. 2. It makes it possible to set highlight the different stages of the process and device according to the second embodiment of the invention (mode incorporating pyrotechnic braking for the actuator (s)).

This flowchart therefore shows the succession of orders generated by the electronic control means 22. The time differences between each initiation will depend on structural features of the turret, cylinders and launch tubes. The skilled person will determine them easily.

Block C1 again corresponds to the supply by the firing line of instructions for positioning the tube in elevation (S) and in deposit (G) as well as the instant (T _R ) at which the defense ammunition must leave the tube. launch.

The control means then calculate (block C2) the instant (T _T ) at which the firing of the ammunition must be controlled so that its exit from the tube occurs at instant T _R. This instant corresponds to the moment of exit of the ammunition (T _R ) minus the stage of ignition of the load 44 and the stage of internal ballistics of the munition in the tube 4.

The control means also calculate (block C30) the instants of initiation (Sa and Sb) of the two pyrotechnic charges of the elevation positioning jack to ensure zero speed in elevation at the time of exit (T _R ).

The control means 22 also calculate (block C40) the initiation instants (Ga and Gb) of the two pyrotechnic charges of the bearing positioning cylinder to ensure a zero bearing speed at the exit instant (T _R ). All calculations will be performed simultaneously.

The control means then cause sequentially the different charge initiations pyrotechnics of the cylinders as well as the firing following the time sequence thus calculated.

Block A10: triggering of positioning in deposit (Ga), block A20 triggering of positioning in site (Sa), block A3 triggering of firing (T _T ). The relative order of trips A10 and A20 will depend on the set angles given on site and in deposit. In the figure, it is considered that the order relating to the positioning of the deposit occurs first. It is of course the longest rally which is triggered first. The objective is to rally on site and in simultaneous deposit at time T _R.

The control means of course ensure control from the firing of the pressures actually obtained in the jacks and they possibly correct (block A40 correction in Cor G deposit; block A50 correction in Cor S site) the instants of triggering of the pyrotechnic braking charges ( block A60 triggering of braking in Gb deposit; block A70 triggering of braking on site Sb) or else control the openings of the vents (E _G , or E _S ).

Line L represents the simultaneity at the planned time T _R of the positions in elevation, in deposit and of the exit of the ammunition out of the tube.

Claims (14)

Method for defending a vehicle (1) or a structure against a threat such as a projectile (6), method employing means for positioning in site and / or in deposit of at least one tube (4) of launching a defense ammunition (5), means which comprise at least one pyrotechnic jack, method in which the speed (V) and the direction (Δ) of the threat are determined using measurement and calculation means , process characterized by the following steps: we determine, from the speed and direction of the threat, the elevation and bearing angles (α) to be given to the launch tube of the defense ammunition as well as the instant at which this ammunition must be ejected from the tube in this direction, the tube positioning means (4) are triggered in sequence, then the munition (5) is fired, command, before or after the positioning means, means ensuring the braking and / or stopping of the positioning means when they have oriented the firing system at the desired angles. Defense method according to claim 1, in which at least one positioning means is a double-acting pyrotechnic jack (10) incorporating two pyrotechnic charges (20a, 20b) having an antagonistic effect each connected to a separate chamber (16a, 16b) , the two chambers being separated by a movable piston (17), a method characterized in that , to ensure the braking of at least one positioning means, the two pyrotechnic charges (20a, 20b) of the jack in question are successively controlled so as to ensure by the action of the second load braking of the displacement of the piston (17) which has been controlled by the first load, the time interval between the initiation of each load being chosen so as to ensure positioning desired for the piston. Defense method according to claim 2 characterized in that the pressure in the first chamber (16a, 16b) in which the first charge (20a, 20b) is initiated is measured, this pressure is compared to a memorized theoretical value and then corrects the time interval before initiation of the second charge and / or a vent (170a, 170b) is opened in at least one of the chambers so as to take account of the difference observed between the theoretical pressure and the pressure measured. Defense method according to claim 3 characterized in that when the pressure measured in the first chamber (16a, 16b) is lower than the memorized theoretical pressure, the instant of initiation of the second charge is delayed and / or a vent is opened (170a, 170b) in the second bedroom. Defense method according to one of claims 3 or 4 characterized in that when the pressure measured in the first chamber is greater than the memorized theoretical pressure, the instant of initiation of the second charge is anticipated and / or a vent is opened (170a , 170b) in the first bedroom. Defense method according to one of claims 2 to 5 characterized in that the actual position of the piston (17) is determined and this measurement is used to correct the instant of initiation of the second charge and / or to open a vent ( 170a, 170b) in one or other of the rooms. Device allowing the defense of a vehicle or a structure against a threat such as a projectile, device implementing the method according to one of the preceding claims and comprising means for positioning in site and / or in deposit of at least one tube for launching a defense ammunition, positioning means which comprise at least one pyrotechnic jack (10a, 10b), device also comprising means for detecting the approach of the projectile and calculation means for determining the angles of elevation and of the deposit to be given to the tube (4) for launching the ammunition (5) of defense as well as the instant at which the ammunition must be ejected from the tube in the direction of fire, device characterized in that it comprises means control electronics (22) ensuring a sequence initiation of the pyrotechnic actuator (s) (10a, 10b) for positioning and then firing of the ammunition (5), as well as means (23a, 23b, 23c, 23 d) ensuring the braking and / or stopping of the positioning means when they have oriented the firing system at the desired angles. Defense device according to claim 7, characterized in that the braking and / or stopping means (23a, 23b, 23c, 23d) of the positioning means are formed by deployable abutment surfaces integral with the body of the jack or jacks pyrotechnics (10a, 10b), the deployment of the abutment surfaces being controlled by the electronic control means (22). Defense device according to claim 8, characterized in that the defense ammunition (5) comprises a zone of spatial efficiency (E1, E2) at a nominal use distance (SI), and in that two abutment surfaces consecutive carried by a cylinder body (10a, 10b) are separated by a distance which determines an angular positioning deviation for the tube (4) ensuring an overlap of the zones of effectiveness of the defense ammunition for the two consecutive directions and at said nominal working distance. Defense device according to claim 7, device characterized in that one of the site and / or deposit positioning means comprises at least one double-acting pyrotechnic cylinder (10a, 10b) incorporating two pyrotechnic charges (20a, 20b) having an antagonistic effect each connected to a separate chamber, the two chambers being separated by a movable piston (17), the electronic control means (22) ensuring a sequential initiation of the two pyrotechnic charges of the jack in question with a chosen time interval of so as to ensure the braking of the piston (17) and the desired positioning in elevation and / or in bearing. Defense device according to claim 10, characterized in that it includes means (150a, 150b) for measuring the pressure in the two chambers of one of the pyrotechnic cylinders (10a, 10b), these means being connected to the electronic means control (22), the latter being able to compare the pressure measured in a first chamber with at least one theoretical value so as to correct the time interval before initiation of the second load of the jack (10a, 10b) considered. Defense device according to one of claims 10 or 11, characterized in that it comprises means making it possible to determine the real position of the piston of the pyrotechnic jack (10a, 10b) or else the positioning in site or in bearing given by this jack, these means being connected to the electronic control means (22). Defense device according to one of claims 11 or 12, characterized in that at least one pyrotechnic cylinder (10a, 10b) comprises at least one vent (170a, 170b) for each chamber, vent the opening of which can be controlled by the electronic control means (22) and allowing said chamber to communicate with the outside. Defense device according to one of claims 10 to 13, characterized in that the electronic control means (22) cause the munition (5) to fire at an instant such that it leaves the tube (4) substantially at the instant where the elevation and bearing angles are obtained.

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