EP0260198A1 - Support device for wide field of view helmet visors, servo controlled relative to the movement between a body and a structure - Google Patents

Abstract

Device for supporting the optical and electronic equipment normally supported by the helmet, without any load for the pilot's head. It comprises a support part (1) placed at a distance from the helmet (2) and means for controlling the position of this part relative to the helmet using a spatial location assembly (6-7) of the part. relative to the body, a computer (8) which determines the positioning errors, a control circuit (5) which produces signals corresponding to these errors and a set of jacks (4) supplied by these signals to modify the position of the support part (1) relative to the aircraft structure (3) and to cancel positioning errors.

Description

The present invention relates to a support device slaved to the movement of a movable body relative to a surrounding structure, the body being a helmet worn by the head of an operator. More specifically, the invention makes it possible to subject the device to the movements of the head, which are exerted in a defined volume, so as to make the device support equipment normally mounted on the helmet and free the operator from the load. corresponding.

The use of the invention is more particularly envisaged in the avionics field to solve the problem of viewing video images in a wide field and with high resolution. In fact, the pilot on board a chasing device is installed in a small passenger compartment and, more often than not, his position is lengthened, which hardly makes it easier for him to view the instruments of the dashboard. A cathodic indicating device which would represent an elaborate video visualization is therefore perceived anyway only from a reduced angle and loses its effectiveness. The collimated display mounted on a helmet restores a certain visual comfort for the pilot but it remains limited to small fields or for higher fields at a medium resolution, for example an image of 250 points per line and 250 lines. The installation on headphones of a wide-field and high resolution display (by high resolution means more than 1000 points per line) results in a prohibitive weight not compatible with the accelerations to be undergone, which can go up to approximately 8g.

The object of the invention is to remedy these drawbacks and limitations by using a support device mechanically decoupled from the pilot's helmet, placed at a short distance from the latter in a defined position and which is controlled by the movements of the head and so the helmet worn by the pilot. This support device can thus play the role of the helmet to carry, in its place, the necessary optoelectric equipment and, in particular, it will be possible to install on this support device a high-resolution wide field display. The pilot is freed from the weight of this equipment and can therefore move his head freely.

According to the invention, a support device is produced which is slaved to the movements of a body movable relative to a surrounding structure, the body being a helmet worn by the head of an operator, this device comprising a support piece placed at a distance from the body from which it is mechanically decoupled, and position servo means for preserving a determined reference positioning of this part with respect to the moving body, so as to make the device support equipment normally mounted on the helmet, these means control system including:
- means for detecting the positioning of the part relative to the body;
- a set of jacks mechanically coupling the support part to the structure;
- means for calculating and controlling the jacks to calculate, from the signals detected by said detection means, the positioning errors of the part with respect to the body and developing corresponding control signals from the jacks to cancel these errors.

• - Fig.1, un diagramme général d'un dispositif support conforme à l'invention appliqué au cas d'un viseur de casque ;
• - Fig.2, un schéma de détail montrant un exemple de détection du positionnement de la pièce par rapport au corps ;
• - Figs.3 à 6, des exemples de combinaison de mouvements des vérins pour produire divers déplacements possibles du dispositif support et montrer les débattements correspondants ;
• - Figs. 7 à 10, les mêmes mouvements mais avec des points d'articulation plus hauts des vérins du côté structure ;
• - Fig.11, un schéma de détail relatif à l'escamotage du dispositif support pour permettre l'éjection du siège.

The features and advantages of the invention will appear in the description which follows, given by way of example with the aid of the appended figures which represent;

• - Fig.1, a general diagram of a support device according to the invention applied to the case of a helmet viewfinder;
• - Fig.2, a detail diagram showing an example of detection of the positioning of the part relative to the body;
• - Figs. 3 to 6, examples of combinations of movements of the jacks to produce various possible displacements of the support device and show the corresponding deflections;
• - Figs. 7 to 10, the same movements but with higher points of articulation of the cylinders on the structure side;
• - Fig.11, a detailed diagram relating to the retraction of the support device to allow the ejection of the seat.

Referring to Figure 1, the device comprises a main part 1 which is placed at a distance from a movable body 2 represented by a conventional helmet placed on the pilot's head, and means for servo-positioning the part 1 in a given reference position relative to the body.

The body 2 is movable relative to a surrounding structure which is in the case considered, the airplane structure 3 partially symbolized by hatching.

The main part 1 is mechanically decoupled from the body 2 and it constitutes the support part for optronic equipment in place of the helmet 2.

The part 1 is held spatially in position vis-à-vis the helmet 2 using mechanical coupling means which connect it to the structure 3, these means being connected to a servo device to maintain the reference position between elements 1 and 2.

The mechanical coupling means 4 are intended to constitute a structure for maintaining the position of the part 1 around its six degrees of freedom, with tracking of the body 2, and which has great precision (of the order of a milliradian). This controlled structure must also respond to a certain number of complementary and specific constraints in the context of the airborne use envisaged. These additional constraints are essentially of three kinds: small footprint given the limited space available; a very high resistance to accelerations, this resistance must be of the order of magnitude of that of the airplane structure, that is to say greater than 10 g; and a clearance both to allow the pilot to take place in the plane and later, if necessary, to control the ejection of the seat. To meet these constraints, the mechanical coupling is ensured with jacks 4 six in number to exercise action according to the six degrees of freedom. Three cylinders are shown in the figure numbered 4.1, 4.2 and 4.3.

The cylinders are advantageously chosen from the double-stroke type, that is to say the stroke is equal to twice the length minus that reduced necessary for guiding.

The other circuits shown comprise, for the position control, a circuit 5 for controlling the jacks, means 6-7 for detecting the positioning of the part 1 relative to the helmet 2 and an annex computer 8.

The position detection means can be produced in various ways which fall into two main categories, optoelectric solutions and magnetic solutions. A known optoelectric solution can be constituted with at least one group of light-emitting diodes forming a triangle and which is associated with a set of elementary optoelectric sensors. An on-board computer processes the detected signals to measure one (or more) reference directions linked to the moving body. A solution of this kind is described in French patent 2 399 033. Each elementary sensor is formed from a DTC array of photosensitive elements which is coupled to a slot to determine a plane passing through the emitting luminescent source. An additional calculation makes it possible to locate the various planes then the triangle formed by the sources and consecutively, the direction to locate. This technique can be transposed in the present case by being modified as indicated in FIG. 2 to lighten the helmet and rid it of active elements. The light-emitting diodes are replaced by so-called reticle designs R1, R2, R3 carried by the helmet 2 and remotely illuminated from a point source S1 carried by the support part 1. The radiation returned by the reticles is received at least partially by the sensor device 7 which comprises a DTC matrix of elements arranged in X, Y. The semi-reflecting mirror M1 at the rear of an O1 optic ensures the separation of the transmission and reception channels and the coaxiality. The crosshairs R1 to R3 may present the drawing indicated as example, and be made of retroreflective material (glued elements or paint). The signals detected SD by the DTC matrix of the sensor on which the image of the illuminated reticles is formed, are a function of the position of the reticles relative to the sensor. These signals are processed by the computer 8 which provides the position data of the part 1 relative to the helmet 2. Data relating to the reference positioning, fixed in advance, are included in the memory of the computer to obtain these conditions d distance from the part 1 relative to the helmet 2. The computer 8 gives the position errors of the body 1 at all times and transforms these error data into control signals SC which are transmitted to the control circuit 5 which supplies the signals corresponding analogs required to control the six cylinders.

The proposed solution applied to a helmet visor brings many advantages which are listed below:
- the device does not add any additional weight or discomfort to the pilot;
- it can support important optics, necessary to realize high-resolution displays in high resolution and in color if necessary, as well as the associated electronics and integrated display screens;
- the direction aimed by the pilot is automatically known with precision;
- additional equipment normally not used in the helmet versions can be added, such as laser protection.

The means for locating the part 1 relative to the body 2 may consist of several assemblies 6,7, for example by doubling this material on either side of the helmet plane of symmetry. The helmet thus carries laterally to the right and to the left a group of three reticles 6A on one side 6B on the other; substantially opposite the part 1 will include a first sensor device 7A on one side and a second sensor 7B on the other side.

The support part 1 can be toroidal in shape as shown in FIG. 1 with the equipment inside the torus optoelectric required. There is shown, by way of example a collimator optic 11 and on the outside a deflection mirror 12, these elements possibly being part of a high resolution wide field collimator device.

The fact that the visualized part of the space changes with the rotation of the head makes it possible to represent a total field of three to six times that of the display device.

For example, if the display device has a field of 50 ° and a resolution of 1000 points per line, the angular resolution is one milliradian for a total field of 150 ° necessary for navigation and reading of the on-board instruments fictitious produced by the support device 1 equipped. With a 15 ° field visualization and also 1000 points per line, an angular resolution of 0.3 milliradian is obtained in a total field of 100 ° necessary to discover the objectives and identify them. Of course, if the display device has a better resolution, all of these performances are further improved.

A symbol generator 9 can be used to produce a determined display and to supply the collimator with corresponding signals SY, via the computer 8.

FIGS. 3 to 6 represent various combinations of movements of the jacks to respond to movements of the support device as a function of the movements of the head of the pilot or of the observer. We considered displacement by translation L1 in the vertical direction which can be carried out towards the "bottom" or towards the "up", L2 in the horizontal direction starting from the initial position of reference known as of "face", this movement L2 being carried out either to the "left" or to the "right"; another displacement by translation L3 is considered from the "face" position towards the "front"; finally an angular movement is considered by an azimuth rotation of ± 45 °. Each of the figures includes a first figure representing the movement in the vertical plane and a second figure representing the movement in the horizontal plane.

Thus, FIGS. 3A and 3B represent, by way of example, a movement resulting from the two translations L1 from top to bottom and L2 from the face position to the left. The support piece passes from the initial rest position 1A to the final position 1B.

FIGS. 4A and 4B represent these same translational movements with, in addition, an azimuth rotation of 45 ° to the left. Position 1C of the part already represents it with this 45 ° rotation.

FIGS. 5A and 5B relate to a third example according to which there is a translation L1 from top to bottom and a translation L3 from the position facing the reference towards the front.

Figure 6 shows the displacements L1 and L3 of Figure 5 with in addition a translation L2 from the face position to the left and an azimuth rotation of 45 °, also to the left.

Figures 7 to 10 correspond respectively to the same movements as Figures 3 to 6 but with higher points of articulation on the side of the structure (points B and C of the cylinders 4-2, 4-3, 4-4 and 4 -5). In this case the relative deflections are lower.

The points of articulation of the jacks, on the structure side 3, are located on the fixed part of the ejectable seat, parts which remain integral with the aircraft structure, or else are directly fixed to the aircraft structure at the rear of the seat and laterally by compared to this one. The points of articulation on the support device side 1 are chosen so that there are at least three points of articulation at the ends of a triangle and so as not to disturb the pilot, that is to say that 'They should not be located forward, which would make the structure difficult, if not impossible, to achieve. The attachment points to the part 1 of the jacks define a plane whose position in space is controlled by jacks 4.

Figure 11 shows schematically the retraction of the support part 1 to allow the ejection of the seat. The ejection means comprise a control 10 (fig. 1) which, by means of the computer, will control the jacks so that the support part 1 come and take the retracted position 1E shown. Part 20 represents the top of the ejection seat, part 21, the fixed amount of the seat secured to the aircraft structure 3.

Claims (7)

1. Support device subject to the movement of a movable body with respect to a surrounding structure, the body being a helmet worn by the operator's head, characterized in that it comprises a support part (1) placed at a distance from the body (2) from which it is mechanically decoupled, and position control means (4 to 8) to preserve a determined reference position of this part with respect to the moving body, so as to make the device support equipment normally mounted on the helmet, these control means comprising:
- Detection means (6,7) for positioning the part with respect to the body;
- a set (4) of cylinders mechanically coupling the support part to the structure (3);
- And calculation means (8) and control (5) of the cylinders to calculate, from the signals detected by said detection means, the positioning errors of the part relative to the body and develop corresponding control signals of the cylinders to cancel these errors. 2. Device according to claim 1, characterized in that it comprises six cylinders (4.1,4.2,4.3 ....) to act according to the six degrees of freedom. 3. Device according to claim 2, characterized in that the jacks (4) are of the double stroke type. 4. Device according to any one of the preceding claims, characterized in that the detection means (6, 7) are of the optoelectric type, comprising at least one assembly composed of a group (6) of reticles (R1, R2, R3) carried by the part (1), an associated photoelectric sensor device (7) which is mounted on the body (2) as well as a source (S1) to illuminate the reticles. 5. Device according to claim 4, characterized in that the reticles (R1, R2, R3) are made of retroreflective material. 6. Device according to any one of the preceding claims, characterized in that the support part (1) has the shape of a torus. 7. Device according to claim 6, used to make a helmet viewfinder by an aircraft pilot, characterized in that said part (1) supports optronic means making it possible to obtain a viewfinder with a large field and at high resolution.

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