EP2948621B1 - Method for determining the position of a cutting device in the ground using a mobile carriage - Google Patents

Description

Background of the invention

The present invention relates to the field of drilling and excavating screens in the ground.

• un châssis suspendu comportant une extrémité supérieure et une extrémité inférieure ;
• au moins un câble s'étendant au-dessus du châssis, ledit câble étant sous tension et ayant une extrémité inférieure fixée à l'extrémité supérieure du châssis ;
• un dispositif de coupe disposé à l'extrémité inférieure du châssis.

More specifically, the invention relates to an excavating machine comprising:

• a suspended frame having an upper end and a lower end;
• at least one cable extending above the frame, said cable being under tension and having a lower end attached to the upper end of the frame;
• a cutting device disposed at the lower end of the frame.

Such an excavating machine is in particular, but not exclusively, a driller with rotating drums, also called hydrofraise. FR 2 211 027 describes such a machine. During the drilling operation, the frame continues a descent movement as its rotating drums dig the trench.

According to another variant, such an excavating machine is a bucket grab bucket, whose actuating mechanism is mechanical or hydraulic.

For some works, the trench can have a great depth that can reach 100 meters or more. In addition, it is generally necessary that this trench has a high accuracy as to its verticality, especially since the final work results from a juxtaposition of panels, for example molded walls or any other type of screens.

Particularly because of the unevenness of the ground in which the trench must be made, there are significant risks that the frame deviates from its vertical trajectory, this risk increasing as the drilling depth increases.

There is therefore a real need for systems to control the verticality, or at least orientation, of movements of the chassis in the ground, detecting any deviations from the desired path.

To resolve this problem, EP 0 841 465 proposes a system for controlling the verticality of a drill rig in which two cables of small section are fixed at the upper end of the machine. These cables are kept under constant tension and pass through two fixed reference points arranged at the upper end of the trench. Thanks to the continuous measurement of the length of the cables, and the angles of inclination of the ends of the cables fixed on the machine, the coordinates of the two cable fixing points are calculated.

This method, which is very satisfactory for drilling depths less than 100 m, however, lacks precision for drilling at greater depth.

Object and summary of the invention

An object of the invention is to provide an excavation machine provided with a chassis trajectory control system providing accurate results, regardless of the depth of drilling.

• un chariot qui est monté coulissant le long du câble ;
• un dispositif pour déplacer le chariot le long du câble ; et
• un dispositif de localisation pour déterminer la position spatiale du chariot.

The invention achieves its object by the fact that the excavating machine further comprises:

• a carriage which is slidably mounted along the cable;
• a device for moving the carriage along the cable; and
• a locator device for determining the spatial position of the carriage.

The carriage, separate from the chassis, is configured to move along the cable, the latter may be a carrier cable which is suspended from the frame and whose function is to carry the frame, or a non-loadable cable which is specifically provided to guide the cart. The carriage moves, preferably, between the surface and the lower end of the cable.

The cable is live. When the cable is carrying, it is understood that it is powered by the action of the weight of the frame. When the cable used to guide the movement of the carriage is not carrying, the machine comprises means for holding the cable under tension.

In practice, the live cable is rarely perfectly straight. It has indeed a curved shape, more or less pronounced depending on the path taken by the chassis during drilling. In the document EP 0 841 465 as a rough approximation, it was assumed that the cables were straight, resulting in good results when drilling depth is low. However, it is understood that for greater depths, this approximation no longer holds because the cables can have a significant curvature.

Moving along the cable, the carriage follows the curvature of the cable. Consequently, knowledge of the spatial position of the carriage makes it possible to know the spatial position of the cable, and in particular the position of the lower end of the cable, which then makes it possible to determine the position of the frame and the cutting device, knowing the length and inclination of the frame.

Preferably, the carriage descends by the effect of its own weight. It may eventually be weighted. For its ascent, the moving means preferably comprise a connecting cable connected to a winch. According to another variant, the carriage comprises a motorized wheel allowing its movement along the cable.

Preferably, the spatial position of the carriage is determined several times during its movement along the cable. "Measuring points" are the successive positions of the carriage along the cable to which measurements are made to determine the spatial positions of said carriage.

Spatial position means in particular the rotation of the carriage relative to a reference position, and its position on the cable. The measurements can be made during the descent of the carriage, or during its ascent.

In order to improve the accuracy of the results, a first series of measurements is taken during the descent of the carriage, a second series of measurement during the ascent of the carriage, and the position of the chassis is determined using the first and second measurement series.

Advantageously, to further improve the accuracy of the results, the carriage is immobilized at each measuring point so that the measurements are made during the stopping of the carriage.

Generally, the chassis is suspended by means of several carrying cables. Without departing from the scope of the present invention, the carriage may be slidably mounted to one or other of the carrier cables.

According to one variant, to improve the accuracy of the results, the carriage is moved along one of the load-bearing cables, the position measurements are carried out along this cable, and then the carriage, or another similar carriage, is moved along another of the carrier cables, and the position measurements are taken along this other cable.

Advantageously, the carriage is configured so that its trajectory is locally coaxial with the cable along which it moves. To do this, the carriage is preferably provided with three wheels that enclose the cable.

Advantageously, the excavating machine according to the invention further comprises a guiding device for preventing the carriage from pivoting about itself around the cable during its movement along said cable. This makes it possible to significantly improve the accuracy of the measurements because a pivoting of the carriage on itself around the cable would have the effect of distorting the measurements.

Preferably, to avoid this pivoting, the frame is fixed to the lower end of a first cable and the lower end of a second cable, the carriage is slidably mounted along the first cable, and the guide device comprises at least one arm integral with the carriage and cooperating with at least the second cable, without adding stress.

An advantage of this configuration is to be able to detect and measure the twisting of the trajectory of the chassis.

As soon as the first and second cables have an angular displacement, considered in a substantially horizontal plane, linked to the rotation of the frame relative to a vertical axis, it is understood that the carriage, thanks to its arm, will be driven in the same movement angular displacement.

Preferably, the arm has a distal end which cooperates with the second cable. This distal end is preferably, but not necessarily, provided with at least one roller whose axis of rotation is substantially perpendicular to the second cable to facilitate the sliding of the arm along the second cable.

According to a variant, the excavation machine according to the invention further comprises a cuttings evacuation pipe which extends above the frame, and the arm is curved so as to be offset relative to the pipe of evacuation. An interest is to avoid a contact between the arm and the evacuation pipe, which would be likely to block or slow the movement of the carriage.

Advantageously, the locating device comprises at least one inclination measuring device disposed in the carriage.

Thus, several measures of inclination of the carriage are made during the movement of the carriage along the cable. As mentioned above, these measurements are made during the descent and / or during the ascent of the carriage.

Advantageously, the measurements are made at predetermined depths or else at predetermined lengths of movement of the carriage along the cable.

According to a preferred embodiment, the locating device comprises first and second inclination measuring devices, arranged in the carriage, arranged to perform inclination measurements in two vertical planes perpendicular to each other.

Thus, by performing a succession of measurements of inclination of the carriage in the two vertical planes, it is determined, by a method of integral calculation, the position of the lower end of the cable, and therefore the coordinates of one of the points of the upper end of the chassis. The calculation is also based on the distance traveled by the carriage between two successive measurements.

Advantageously, but not necessarily, the machine according to the invention further comprises guiding means arranged above the ground surface to keep immobile in a horizontal plane the cable area disposed in said plane as and when the lowering the frame, the guide means for defining at least one fixed reference position, so that the position of the lower end of the cable is determined relative to the fixed reference point.

Preferably, the guiding means make it possible to define as many reference fixed positions as there are cables. More preferably, the guide means comprise fixed guide means in which the cables pass, said fixed guide means being disposed at the surface of the ground in a horizontal plane facing the trench.

The guide means therefore make it possible to simplify the calculation. However, we can do without it. In this case, account should also be taken of the displacement, in a horizontal plane situated on the surface, of the zone of the cable situated in the said horizontal plane. For example, when the excavating machine according to the invention is a grab, which periodically rises to the surface each time its cups are filled with cuttings, it will not be possible to set up the guide means.

Advantageously, by performing the same type of measurements by moving the carriage along another cable, the coordinates of another point of the upper end of the frame are determined.

To improve the accuracy of the measurements, it determines the twisting angle of the trajectory of the carriage concomitantly with the measurements of its inclination. To do this, the locating device further comprises a device for measuring the angle of rotation of the carriage in a plane substantially perpendicular to the cable.

This pivoting, also called twisting, participates in the calculation of the spatial location of the carriage.

According to a preferred embodiment, the carriage is provided with a memory for storing the data measured by the locating device during the movement of the carriage. These data are then transferred to calculation means arranged on the surface, this transfer preferably taking place when the carriage is raised to the surface. According to one variant, the transfer takes place in real time via the connecting cable.

Advantageously, the locating device further comprises a device for determining the length of the movement of the carriage along said cable. Preferably, the device for determining the length of the movement of the carriage along the cable determines the unrolled length of the connecting cable.

Preferably, the means for moving the carriage are configured so that the speed of descent and / or rise of the carriage along the cable is controlled.

According to the invention, the excavating machine further comprises a device for determining the position of the chassis from the measurement data taken by the locating device during the movement of the carriage along the cable. This device implements a calculation step which, from all the measurements made, makes it possible to determine the coordinates of at least the lower end of one of the cables attached to the upper end of the frame.

To position the cutting device, the frame comprises an inclinometer for determining the inclination of the frame relative to the vertical, and the machine further comprises a device for determining the position of the cutting device from the position, the length and inclination of the frame.

According to another variant, the machine further comprises a muffle, known in addition, which is pivotally mounted at the upper end of the frame relative to the longitudinal axis of the frame. The machine also comprises measuring means for measuring the angle of rotation of the muffle with respect to the frame. In this variant, the cables are connected to the pivoting muffle so that the frame can pivot relative to the cables. The position of the cutting device is then determined in the same way as above except that the angle of rotation of the muffle supplied by the measuring means is furthermore used.

• on fournit une machine d'excavation selon l'invention ;
• on réalise une étape de forage en faisant pénétrer le châssis dans le sol ;
• on réalise une étape de déplacement du chariot le long du câble au cours de laquelle on mesure, en différents points de mesure, la position spatiale du chariot ; et
• on détermine la position du châssis dans le sol à partir des mesures de position du chariot.

The present invention further relates to a method of drilling in a soil, wherein:

• an excavation machine according to the invention is provided;
• a drilling step is carried out by penetrating the frame into the ground;
• a step of moving the carriage along the cable during which the spatial position of the carriage is measured at different measurement points; and
• the position of the chassis in the ground is determined from the position measurements of the truck.

Advantageously, to improve the accuracy of the measurements, the carriage is immobilized at each measurement point during the measurement of the spatial position of the carriage. Of course, one could however make the measurements on the fly, without stopping the carriage.

Preferably, the movement of the carriage is stopped at each measuring point the time to realize the measurement of its spatial position. For example, the truck will be immobilized every 0.5 m, 1 m or 2 m of cable.

Preferably, the cable is immobilized before carrying out the step of moving the carriage, and several steps are performed for moving the carriage during the drilling step, so as to determine several positions of the chassis in the ground and of 'get the real trajectory of the chassis in the ground. The immobilization of the cable may for example be obtained by stopping the descent of the chassis.

Advantageously, a mathematical processing of the position measurements of the carriage is carried out, preferably by integration, in order to determine the coordinates of at least the lower end of the cable fixed to the upper part of the chassis. These coordinates are preferably relative coordinates with respect to the aforementioned fixed reference position. Preferably, to improve the accuracy of the measurements, several steps of moving the carriage along the same cable are carried out. Still preferably, in some of the steps of moving the carriage along the same cable, the sensors are turned 180 ° in order to cancel the calibration errors.

According to a variant, steps of moving the carriage along the other cables are carried out in order to determine the coordinates of the lower ends of other cables fixed to the upper part of the chassis. This allows in particular to recalculate the distances between the cables to control that they are consistent with actual distances. An interest is therefore to control the quality of the measured values. Another interest is to determine the rotation of the upper part of the frame relative to the horizontal.

Advantageously, the inclination of the frame is measured and the position of the cutting device in the ground is determined from the position of the frame and the measurement of the inclination of the frame.

According to a particularly advantageous embodiment, the actual trajectory is compared with a predetermined trajectory of the chassis. in the ground, and the positioning of the chassis is corrected during the drilling step to minimize the difference between the actual path and the predetermined path. This positioning correction is achieved by actuators arranged on the frame and which are controlled from the surface. In known manner, these actuators consist of pads actuated by hydraulic means for exerting a thrust on the walls of the trench to change the path of the frame.

Advantageously, the actual trajectory of the cutting device, which is preferably compared to a predetermined trajectory, is determined in order to correct any detected deviation.

The invention finally relates to the carriage intended to be slidably mounted on a cable connecting the surface to the excavating machine according to the invention.

Brief description of the drawings

• la figure 1 est une vue d'ensemble de la machine d'excavation selon l'invention en cours de forage ;
• la figure 2 est une vue de dessus des moyens de guidage destinés à être disposés dans un plan horizontal en surface et en regard de la tranchée ;
• la figure 3 illustre le début de l'opération de forage, le châssis étant représenté en vue de face, dans un plan orthogonal à l'épaisseur de la tranchée, le châssis étant orienté verticalement ;
• la figure 4 est une vue latérale du châssis de la figure 3 ;
• la figure 5 illustre le châssis immobilisé à grande profondeur, en vue de face, dans un plan vertical orthogonal à l'épaisseur de la tranchée, la trajectoire du châssis ayant dévié par rapport à la verticale selon une direction X parallèle à la largeur de la tranchée;
• la figure 6 est une vue latérale du châssis de la figure 5 , illustrant la déviation de la trajectoire du châssis par rapport à la verticale selon une direction Y parallèle à l'épaisseur de la tranchée ;
• les figures 7A à 7D illustrent la position de l'un des câbles du châssis des figures 5 et 6 dans des plans horizontaux situés à différentes profondeurs auxquelles la position du chariot est déterminée ;
• la figure 8 illustre le déplacement du chariot selon l'axe X entre deux mesures successives ;
• la figure 9 illustre le déplacement du chariot selon l'axe Y entre deux mesures successives ;
• la figure 10 est une vue de détail du chariot ; et
• la figure 11 est un schéma illustrant le traitement mathématique des signaux utilisés pour déterminer la position du dispositif de coupe du châssis dans le sol.

The invention will be better understood on reading the following description of an embodiment of the invention given by way of non-limiting example, with reference to the appended drawings, in which:

• the figure 1 is an overview of the excavating machine according to the invention during drilling;
• the figure 2 is a top view of the guide means intended to be arranged in a horizontal plane at the surface and facing the trench;
• the figure 3 illustrates the beginning of the drilling operation, the frame being shown in front view, in a plane orthogonal to the thickness of the trench, the frame being oriented vertically;
• the figure 4 is a side view of the chassis of the figure 3 ;
• the figure 5 illustrates the chassis immobilized at great depth, in front view, in a vertical plane orthogonal to the thickness of the trench, the trajectory of the chassis deviated from the vertical in a direction X parallel to the width of the trench;
• the figure 6 is a side view of the chassis of the figure 5 , illustrating the deviation of the chassis trajectory by vertical ratio in a Y direction parallel to the thickness of the trench;
• the Figures 7A to 7D illustrate the position of one of the chassis cables figures 5 and 6 in horizontal planes at different depths at which the position of the carriage is determined;
• the figure 8 illustrates the displacement of the carriage along the X axis between two successive measurements;
• the figure 9 illustrates the movement of the carriage along the Y axis between two successive measurements;
• the figure 10 is a detail view of the cart; and
• the figure 11 is a diagram illustrating the mathematical processing of the signals used to determine the position of the frame cutter in the ground.

Detailed description of the invention

On the figure 1 an excavating machine 10 according to the present invention is shown in the course of drilling a trench T in soil S adjacent to a screen E already in place in the ground.

In the remainder of the description, "thickness" means the smallest dimension of the trench T considered in a horizontal plane, and "width" means the largest dimension of the trench T considered in the horizontal plane. Depth means the height of the trench considered in a vertical direction.

Finally, the description is made with reference to an orthogonal coordinate system X, Y, Z, where X is an axis parallel to the width of the trench, Y is an axis parallel to the thickness of the trench, and Z is a vertical axis. downwards.

In this example, the excavating machine 10 is a hydrofraise. The excavating machine comprises a suspended frame 12 having an upper end 14 and a lower end 16.

The frame extends in a longitudinal direction DL, and has a length L.

A cutting device 18 provided with rotary drums 20 is attached to the lower end 16 of the frame 12.

In a conventional manner, the chassis 12 is suspended from a hoisting apparatus 22. To this end, the excavating machine comprises, in this nonlimiting example, first, second, third and fourth carrying cables referenced 30, 32, 34 and 36. Each cable has a lower end 30a, 32a, 34a and 36a which is attached to the upper end 14 of the frame. A, B, C and D are the points of attachment of the cables 30, 32, 34 and 36 to the upper part of the frame. In known manner, the upper ends of the cables are mounted on one or more drums carried by the lifting gear 22.

The cables are carrying, in that they carry the frame 12. It is understood that the cables are energized by the action of the weight of the frame. It is also understood that the cables extend above the frame 12.

The excavating machine 10 further comprises a cutout evacuation pipe 13 which extends above the frame, being connected to the upper end 14 of the frame. As we see on the figure 1 , the carrying cables 30, 32, 34 and 36 are arranged around and extend substantially parallel to the discharge pipe of the cuttings 13.

According to the present invention, the excavating machine 10 comprises a carriage 50 which is slidably mounted along the first cable 30. As will be explained above, the carriage 50 is configured to slide along the other three cables 32 , 34 and 36.

The carriage 50, illustrated on the figure 10 , comprises a body 52 to which are fixed three rollers 54 which allow the carriage 50 to slide along said cable 30. The rollers 54 are arranged on either side of the cable so as to grip it, thanks to which the carriage 50 is slidably mounted along the cable.

In this example, the movement of the carriage 50 along the first cable 30 is achieved by a device which comprises a connecting cable 60 connected to the body 52 on the one hand, and to a drum 62 disposed on the surface, on the other hand . If the carriage can descend along the cable due to the action of its own weight, however its speed of descent is controlled by the action of the drum 62.

The drum 62 also has the function of raising the carriage 50 at a controlled speed.

In order to prevent the carriage 50 from pivoting around itself around the cable 30 during its movement, a guiding device 56 is provided which comprises an arm 56, integral and perpendicular to the body 52, and which cooperates with another cable, in this example the second cable 34. The first and second cables are located in the same half-thickness of the frame, but not in the same half-width of the frame.

The arm 56 has a distal end 56a which cooperates with the second cable. In this example, the distal end 56a comprises two rollers 58 whose axes of rotation are substantially parallel to the arm, and whose function is to minimize friction between the arm and the second cable 34.

In the example shown in figure 1 , the arm 56 is curved so as to be offset relative to the discharge pipe 13. This avoids the risk that the arm comes into contact with the discharge pipe, which could slow or block the movement of the carriage.

In this embodiment, the excavating machine 10 further comprises guide means 70 of the first, second, third and fourth cables 30, 32, 34 and 36. These guide means 70 consist of sleepers 72 which comprise four guide rings 74 for guiding the cables. As we see on the figure 3 These guide means 70 are positioned on the surface, and have the function of keeping motionless in a horizontal plane Q areas of the cables arranged in the horizontal plane Q.

During the drilling operation, which will be described below, the guide means are fixed relative to the ground, so that the carrying cables remain "immobile" in the horizontal plane Q. The guide rings 74, which may well heard to present another form, define four fixed reference positions, called A ⁰ , B ⁰ , C ⁰ and D ⁰ . Preferably, the position of the rings coincides with that of the attachment points A, B, C and D when the upper end of the frame is substantially in the horizontal plane Q.

It is understood that, thanks to the guiding means, the reference points A ⁰ , B ⁰ , C ⁰ and D ⁰ do not depend on any movements or deflection of the frame 12.

As mentioned above, an object of the invention is to determine the position of the cutting device in the soil during the step drilling. For this, we will begin by determining the position of the frame 12 in the ground, and more particularly the position of the upper part of said frame. To do this, at least the distance between the fixing point A of the first cable 30 is measured with respect to the fixed reference position A ⁰ .

In order to more precisely determine the position of the upper part of the frame, preferably the displacement of the fixing points B, C and D of the other cables is also measured with respect to the fixed positions of associated references B ⁰ , C ⁰ and D ⁰ .

According to the invention, the distance between the attachment point A of the first cable relative to the fixed reference position A ⁰ is determined by the displacement of the carriage 50 along the cable, between the reference position A ⁰ and the fixing point A. This movement can be a descent along the cable or a lift.

During the step of moving the carriage 50 along the first cable 50, the spatial position of the carriage 50 is periodically measured by means of a localization device. During the moving step, the first cable is held stationary. To do this, in this example, it stops the descent of the frame 12.

It is therefore understood that the first cable is stationary during the movement of the carriage 50 and the realization of measurements.

Referring to figures 5 and 6 , It is understood that, at a time t, which is performed a measurement of spatial position, the position of the carriage 50 of the first cable 30 is denoted by A ^i, where "i" is an integer between 1 and N. In this For example, N measurements of the spatial position of the carriage are thus carried out. The N positions of the carriage, for which a measurement is made, called measuring points, are distributed along the first cable. As a result, the measurement point A ^N is preferably merged with the point of attachment A, or at least located in the immediate vicinity of said point of attachment. Preferably, the carriage 50 is immobilized at each measuring point ^A.sub.i , so that the carriage is stopped during the measurement, which makes it possible to obtain more precise measurement values.

• un angle d'inclinaison α par rapport à la verticale, cette inclinaison correspondant à une rotation du chariot 50 autour de l'axe Y, comme cela est illustré sur la figure 5 ;
• un angle d'inclinaison β par rapport à la verticale, cette inclinaison correspondant à une rotation du chariot 50 autour de l'axe X, comme cela est illustré sur la figure 6 .

The locating device firstly comprises first and second inclination measuring devices 80, 82, arranged in the carriage 50, arranged to perform inclination measurements in two vertical planes perpendicular to each other. These inclination measuring devices, in this case inclinometers, make it possible to measure:

• an angle of inclination α with respect to the vertical, this inclination corresponding to a rotation of the carriage 50 around the axis Y, as illustrated in FIG. figure 5 ;
• an angle of inclination β with respect to the vertical, this inclination corresponding to a rotation of the carriage 50 about the axis X, as illustrated on FIG. figure 6 .

When the frame is purely vertical, it is understood that the carrier cables are also vertical, as a result of which, the angles of inclination α and β are zero.

It is also understood that when the frame deviates from its vertical trajectory, the load-bearing cables have a tendency to bow to and to bend, as illustrated on the drawings. figures 1 , 5 and 6 , which has the effect that the carriage tilts with respect to the vertical direction. In this case, at least one of the angles α and β is non-zero.

The values of the angles of inclination α and β measured at the point A ⁱ are denoted α ⁱ and β ⁱ . Also, at each measurement point A ⁱ , the carriage being preferentially stopped, the angles α ⁱ and β ⁱ are measured. The angles of inclination α ⁱ and β ⁱ , where i = 1..N measured during the displacement of the carriage are, in this example, stored in a memory 51 disposed in the carriage 50.

The locating device further comprises a device 84 for determining the length of the displacement of the carriage along the first cable 30. The length l corresponds to the length l of the connecting cable 60 which is unwound from the reel 62. The device 84 allows naturally to measure the displacement Δl ⁱ infinitesimal of the carriage 50 between two successive measuring points A ^i-1 and A ⁱ . The value of the displacement Δl ⁱ may be chosen as a constant value Δl imposed by the drum 62. According to one variant, the displacement Δl ⁱ is measured by means embedded in the carriage.

In this example, the speed of movement of the carriage is controlled. For this purpose, we will choose a constant ascent and / or descent rate, between 1 and 10 m / s.

In the variant shown, the locating device further comprises a device 86 for measuring the angle of rotation Θ ⁱ of the carriage 50 in a substantially orthogonal plane perpendicular to the cable, with respect to a reference angular position Θ ⁰ . In this example, the angle of rotation Θ is measured in a horizontal plane. Due to the presence of the arm 56, the rotation angle Θ corresponds to the twisting angle of the cables with respect to a straight line passing through the reference points A ⁰ and B ⁰ . The angle of rotation Θ ⁱ will preferably be measured at each measuring point A ⁱ , and in particular at the final position A ^N, so as to give an estimate of the rotation of the upper part of the chassis with respect to the reference line passing through the positions reference A ⁰ and B ⁰ . The rotation angles Θ ⁱ are stored in the memory S1 of the carriage.

Referring now to Figures 8 and 9 it is understood that the values α ⁱ and β ⁱ , Θ ⁱ and Δl ⁱ make it possible to determine the infinitesimal displacements ΔX _A ⁱ and ΔY _A ⁱ along the X and Y axes, by trigonometric calculation. These displacements ΔX _A ⁱ and ΔY _A ⁱ are also represented on the Figures 7A to 7D which illustrate, in horizontal section, a few measuring points A ¹ , A ⁱ and A ^N of the carriage 50 to which the measurements of the truck's spatial position are made.

According to another advantageous aspect of the invention, the excavating machine further comprises a device 90 for determining the position of the frame 12 from the measurement data, namely the values α ⁱ , β ⁱ and Θ ⁱ taken by the first and second inclination measuring devices 80,82 of the locating device, and by the device 86 measuring the twisting of the cables during the movement of the carriage along the first cable 30.

In this example, this device 90 comprises mathematical processing means for calculating the aforementioned displacements ΔX _A ⁱ and ΔY _A ⁱ and then, by an integral calculation, to determine the displacement values ΔX _A and ΔY _A along the X and Y axes. point A relative to the fixed reference position A ⁰ .

The position of the frame 12, and more particularly that of its upper part 14, is determined from the displacement values ΔX _A and ΔY _A , and the depth of the point A which can be determined for example from the unrolled length of the first cable 30 or using another type of depth gauge attached to the frame.

The value of the number of measuring points N will be chosen sufficiently large to provide a precise result, it being understood that the value N may depend on the depth reached by the frame. As non-limiting examples, N will be chosen so as to measure every 0.20 m, 0.5 m, 1 m or 2 m of cable.

To do this, preferably the measurement is made at fixed time intervals, the carriage being moved at a constant speed.

To improve the accuracy of the measurements, it will be possible to increase the number of measurement points N by taking measurements during the descent and during the ascent of the carriage. These steps can also be implemented by sliding the carriage 50 along the other cables in order to determine the position of the points B, C and D.

According to another advantageous aspect of the invention, the excavating machine further comprises a device 92 for determining the position of the cutting device 18 in the ground, from the position of the frame, and more particularly from the position of the upper part of the frame 12. The position of the cutting device 18 is also determined from the length (or height) L of the frame and its inclination with respect to the vertical.

The inclination of the frame 12 is measured using an inclinometer 100 disposed in the frame 12 which measures a first angle of inclination γ relative to the vertical, illustrated in FIG. figure 5 , and a second angle of inclination δ with respect to the vertical, illustrated on the figure 6 . The first and second inclination angles are measured in two vertical planes orthogonal to each other.

The relative position of the cutting device 18 with respect to the points A, B, C and D being known, the knowledge of the position of the points A, B, C and D and the inclination of the frame makes it possible to calculate for example the position a midpoint W located between the rotary drum attack zones.

To improve the accuracy of the measurement, account is also taken of the rotation Θ of the upper part of the frame 12.

On the figure 11 Schematically shows the mathematical processing of information delivered by the various aforementioned measuring and for calculating the position of the median point W of the cutting device.

The device 90 for determining the position of the frame 12 receives the values α ⁱ and β ⁱ , Θ ⁱ measured during the displacement of the carriage by the inclinometers arranged in the carriage and Δl ⁱ , measured by the device 84 to determine the length of the displacement. of the carriage along the first cable 30. The device 90 calculates the coordinates of the points A, B, C and D. The device 92 for determining the position of the cutting device receives the coordinates of at least the attachment point. A, and the values of the first and second inclination angles of the frame γ and δ provided by the inclinometer 100 secured to the frame. The device 92 then provides the coordinates of the midpoint W.

During drilling, several steps of movement of the carriage are performed at different depths of the frame 12, in order to determine a plurality of positions of the frame and the cutting device, which makes it possible to obtain the real trajectory of the chassis, and the cutting device, in the soil S.

The comparison of the actual trajectory with the predetermined (desired) trajectory of the chassis makes it possible to determine the deviation or deviation of the trajectory of the chassis. This difference is minimized during drilling by the actuation of trajectory correction means, for example hydraulic pads 110 arranged on the faces of the frame. These pads 110, bearing against the edges of the trench, allow to change the inclination of the frame, and therefore its trajectory.

Claims (16)

1. An excavator machine (10) comprising:

   • a suspended casing (12) having a top end (14) and a bottom end (16);

   • at least one cable (30, 32, 34, 36) extending above the casing, said cable being under tension and having a bottom end (30a, 32a, 34a, 36a) fastened to the top end of the casing;

   • a cutter device (18) arranged at the bottom end of the casing;

   the excavator machine being characterized in that it further comprises:

   • a carriage (50) that is mounted to slide along the cable;

   • a device (60, 62) for moving the carriage along the cable; and

   • a locator device (80, 82, 84, 86) for determining the three-dimensional position of the carriage.
2. An excavator machine according to claim 1, characterized in that it also comprises a guide device (56) for preventing the carriage from pivoting on itself about the cable (30) as it moves along said cable.
3. An excavator machine according to claim 2, characterized in that the casing (12) is fastened to the bottom end of a first cable (30) and to the bottom end of a second cable, in that the carriage is mounted to slide along the first cable, and in that the guide device comprises at least one arm (56) secured to the carriage and co-operating at least with the second cable (32).
4. An excavator machine according to any one of claims 1 to 3, characterized in that the locator device includes at least one device (80, 82) for measuring tilt that is arranged in the carriage.
5. An excavator machine according to claim 4, characterized in that the locator device has first and second devices (80, 82) for measuring tilt that are arranged in the carriage and that are arranged to measure tilt angles (αⁱ, βⁱ) in two mutually perpendicular vertical planes.
6. An excavator machine according to claim 4 or claim 5, characterized in that the locator device further comprises a device (86) for measuring the angle of rotation (Θⁱ) of the carriage in a plane substantially perpendicular to the cable.
7. An excavator machine according to any one of claims 1 to 6, characterized in that the locator device further comprises a device (84) for determining the length (ℓ) of the movement of the carriage along said cable.
8. An excavator machine according to any one of claims 1 to 7, characterized in that the means (60, 62) for moving the carriage comprise a connection cable (62) fastened to the carriage.
9. An excavator machine according to any one of claims 1 to 8, characterized in that it further comprises a device (90) for determining the position of the casing from the measurement data taken by the locator device during the movement of the carriage along the cable.
10. An excavator machine according to claim 9, characterized in that the casing includes an inclinometer (100) enabling the tilt of the casing to be measured relative to the vertical, and in that the machine also comprises a device (92) for determining the position of the cutter device from the position, the length, and the tilt of the casing.
11. An excavator machine according to any one of claims 1 to 10, characterized in that it further comprises guide means (70) arranged at the surface to hold stationary in a horizontal plane (Q) the zone of the cable that lies in said plane while the casing is being lowered, said guide means serving, at least at the instants that measurements are taken, to define at least one fixed reference position (A⁰, B⁰, C⁰, D⁰) in three-dimensional relationship with the bottom end of the cable when it is in the horizontal plane.
12. A method of boring into soil, the method comprising the following steps:

    • providing an excavator machine according to any one of claims 1 to 11;

    • performing a boring step by causing the casing to penetrate into the soil;

    • performing a step of moving the carriage along the cable, during which step the spatial position of the carriage is measured at different measurement points; and

    • determining the position of the casing in the soil from the three-dimensional position measurements of the carriage.
13. A method according to claim 12, wherein the carriage is held stationary at each measurement point.
14. A method according to claim 12 or claim 13, wherein the tilt of the casing is measured and the position of the cutter device in the soil is determined from the position of the casing and the measured tilt of the casing.
15. A method according to any one of claims 12 to 14, wherein, the cable is held stationary prior to performing the step of moving the carriage, and wherein a plurality of steps of moving the carriage are performed during the boring step, so as to determine a plurality of positions of the casing in the soil and so as to obtain the real path followed by the casing in the soil.
16. A boring method according to claim 15, wherein the real path followed is compared with a path that is predetermined for the casing in the soil, and the positioning of the casing is corrected during the boring step in order to minimize the offset between the real path and the predetermined path.

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