Method for controlling a laying head of a tire component with a simplified path

Description

[0001] The present invention relates to the field of manufacturing tires for vehicle wheels, and more particularly to the field of controlling the installation heads intended to install a tire component by winding it onto a rotating manufacturing support of the core or drum type.

[0002] It is known to manufacture a bandage, in particular a pneumatic bandage, by winding in helical turns on a core having a curved profile, of toroidal shape, a plurality of bandage components, such as one or more continuous strips of raw rubber, that is to say of unvulcanized rubber, for example a strip of raw rubber intended to form the tread of the bandage, or one or more reinforcing strips containing continuous reinforcing threads oriented parallel to the longitudinal direction of the reinforcing strip, in order to form one or more reinforcing belts.

[0003] It is known in this respect in particular from documents EP 1 533 107 and WO 2019 / 235932 to use a robotic arm which carries a laying head designed to convey and lay the bandage component in question on the core. Of course, it is then necessary to control said robotic arm in order to position, orient and move the laying head appropriately along the profile of the core, according to an adequate laying trajectory.

[0004] As such, it is sometimes difficult to find a good compromise between, on the one hand, the precision of the installation, which requires multiplying the points used to define the installation trajectory, and on the other hand, the storage and computer processing capacities of the control unit which controls the robotic arm, which do not always allow a large quantity of data to be managed in real time.

[0005] Of course, smoothing algorithms are also known which, in particular by means of Bézier curves, allow a succession of profile points to be replaced by a trajectory curve modelled by a polynomial parametric function, which allows a simplified approximation of the profile. Such Bézier curves have the main advantage of presenting a continuity of their curvature, and therefore a smooth trajectory curve.

[0006] That being said, such smoothing algorithms require relatively high computing power, and are in any case not suitable for managing certain categories of robotic arms, in particular certain categories of six-axis anthropomorphic robotic arms, insofar as said robotic arms are incapable of processing a Bézier curve type instruction, and can only operate with so-called “segment-based” servoing, i.e. one in which the instruction is expressed in the form of a trajectory table which lists in order all of the successive points, in finite number, which constitute the trajectory to be followed.

[0007] The objects assigned to the invention therefore aim to remedy the aforementioned drawbacks and to propose a new method for defining a trajectory of a laying head intended to lay bandage components on a core, a method which allows segmental and real-time control of a laying head having modest computer processing capacities, while nevertheless guaranteeing satisfactory precision and quality of the laying operation.

[0008] The objects assigned to the invention are achieved by means of a method for defining a trajectory of a laying head, and a corresponding method for controlling a laying head, said laying head being intended to lay at least one bandage component by winding said bandage component in turns on a receiving face of a core driven in rotation around its central axis, said receiving face having, along said central axis, a predetermined profile, said method comprising: a step (a) of geometric characterization of the profile, during which the outline of the profile of the receiving face is provided and a first set of remarkable points, called "geometric remarkable points", is isolated on this profile, which are considered characteristic of the shape of said profile, and said geometric remarkable points are stored in the form of a set of trajectory points called "trajectory table", a step (b) of functional characterization of the profile, during which a plurality of functional zones are determined on the profile, each extending from a zone start point to a zone end point, and a laying law is associated with each of said functional zones, which specifies conditions for laying the bandage component in the functional zone considered, and said zone start points and said zone end points are inserted, forming a second set of remarkable points called "functional remarkable points",in the trajectory table, , then a meshing step (c) during which, considering a predetermined direction of travel of the profile, a series of equidistant virtual points, called "potential guidance points", which delimit two by two straight line segments all having an identical length, equal to a predetermined chosen value, called "unit resolution step", are defined on the profile, from the first functional remarkable point, that is to say from the start point of the first functional zone, taken as the origin, to the last functional remarkable point, that is to say to the end point of the last functional zone, and said potential guidance points are inserted into the trajectory table, then a simplification step (d) during which the size of the trajectory table is reduced by applying one or more selection criteria to the trajectory table in order to select at least one part, and only one part,potential guidance points and remarkable geometric and functional points contained in the trajectory table, and by eliminating the unselected points, so as to obtain a simplified trajectory table, of reduced size, within which at least one and preferably several of the segments which connect two by two the successive selected points have a length strictly greater than the chosen unit resolution step.

[0009] Advantageously, the method according to the invention makes it possible to clearly identify, and therefore to clearly take into consideration, the remarkable points which require particular attention, whether to define the geometry of the profile, in particular in the portions of the profile where said profile has a certain geometric singularity such as a pronounced curvature, or to signal functional singularities, in this case changes in the laying law, for example when the pitch or the winding speed of the bandage component is modified.

[0010] Furthermore, the mesh initially proposed by the process, thanks to the multiple potential guidance points, offers the possibility of having a particularly fine mesh whenever necessary.

[0011] Thus, depending on the situation in the section of the profile concerned, we can locally: either preserve and exploit the fineness of the mesh, by maintaining a high density of selected points in order to maintain a fine resolution, implementing short segments whose length is equal to the unit resolution step, and therefore in order to ensure good installation precision in the portion of the profile concerned; this will typically be applicable in the portions of the profile where a geometric or functional singularity is present, and more particularly, in a concrete manner, in the vicinity of the remarkable points; or on the contrary “relax”, that is to say de-densify, the mesh by selecting and retaining only a part of the potential guidance points from among all the potential guidance points available in the portion of the profile concerned, and therefore by lengthening in this portion of the profile the segments which separate two consecutive trajectory points;this will typically be applicable in portions of the profile that exhibit less variability, including little or no changes in the direction of the profile path and some consistency in the laying law.

[0012] As an indication, it will be possible to increase the density of selected points and thus define shorter segments in the portions of the profile which correspond to changes in the laying law and in the portions of the profile which present marked changes in direction, in tight turns, and therefore a small radius of curvature, such as is particularly the case at the shoulders of the bandage, that is to say in the transition zones between the top of the bandage which forms the tread and the sides of the bandage which connect said top to the rim. It will also be possible, on the contrary, to space out the selected points and therefore lengthen the segments particularly in the almost flat top of the bandage, which corresponds to the tread.

[0013] Ultimately, thanks to the invention, it will be possible to develop, then transmit to the robotic arm, a trajectory table which will be particularly light, because it contains relatively few points ultimately selected, but in which said selected points will be distributed so as to concentrate in order to tighten their mesh in the most complex and most delicate portions of the profile to produce, to guarantee the high precision required in these portions, and on the contrary to be further spaced in order to reduce the density of the mesh in the simpler portions, which tolerate less precision in the control of the trajectory.

[0014] Other objects, characteristics and advantages of the invention will appear in more detail on reading the description which follows, as well as with the aid of the appended drawings, provided for purely illustrative and non-limiting purposes, among which: There figure 1 illustrates, in a top view, a bandage manufacturing installation capable of implementing a method according to the invention. The figure 2 illustrates an example of a profile of the receiving face of the core, corresponding to the section of said receiving face in a meridian plane of the core containing the central axis of said core, and on which a plurality of remarkable geometric points have been identified. figure 3 illustrates a schematic view of a profile on which the geometric and functional notable points have been identified. figure 4 illustrates, in a schematic view, the meshing stage during which the profile of the figure 3 by means of a series of equidistant potential guidance points. The figure 5 illustrates the application of a first selection criterion during which we select, on the profile of the figure 4 , the potential guide points that frame the remarkable points. The figure 6 illustrates, in a schematic view, the principle of a second selection criterion, by authorized deviation limit, according to which it is ensured that, for each trio of selected points, the two adjacent straight line segments which connect two by two the consecutive selected points do not deviate from the corresponding interpolating circle beyond a predetermined admissible deviation value. figure 7 illustrates the application of the second selection criterion by authorized deviation limit, and the addition of the corresponding selected points, on the profile of the figure 5 . There figure 8 illustrates the application to the profile of the figure 7 of a third selection criterion, by maximum permitted segment length, according to which intermediate potential guidance points are added to the selection when a segment is detected, connecting two selected points, the length of which exceeds a maximum permissible length value. figure 9 illustrates the application to the profile of the figure 8 of a fourth selection criterion, by degree of quality, during which we add to the selection of points of the figure 8 potential guidance points that are immediately adjacent to the points already selected. figure 10 illustrates the trajectory which corresponds to the simplified trajectory table finally obtained after applying the above selection criteria to the profile of the figure 3 .

[0015] The present invention relates to a method for defining a trajectory of a laying head 1.

[0016] Said laying head 1 is intended to lay at least one bandage component 2 by winding said bandage component 2 in turns, preferably in turns which are contiguous or partially overlapping from one turn to the next, on a receiving face 4A of a core 4 which is itself driven in rotation around its central axis X4.

[0017] The tire component 2 may be a continuous strip of raw rubber, or even a continuous wire reinforcement element, which has a length much greater, and in particular at least 100 times or even 1000 times greater, than its largest transverse dimension. Said continuous wire reinforcement element may be formed for example of a reinforcing wire or cable made of metallic material, fiberglass, or polymer chosen for its tensile strength, such as aramid, said wire or cable possibly being coated with raw rubber. Alternatively, said continuous wire reinforcement element may be formed by a reinforcing strip comprising several continuous reinforcing wires or cables, made of metal, fiberglass, or polymer such as aramid, which are arranged parallel to each other in the longitudinal direction of the strip and embedded in a matrix, for example made of raw rubber or resin possibly itself coated with an overlayer of raw rubber.

[0018] The laying head 1 is carried by a robotic arm 5 mounted movably on a base 6.

[0019] Said robotic arm 5 is preferably a six-axis anthropomorphic robotic arm. In a manner known per se, such a robotic arm 5 comprises a first joint called "shoulder" forming a connection comprising at least two orthogonal pivot axes between the base 6 and a first segment called "arm" which in turn carries a second joint called "elbow" preferably comprising at least one pivot axis to ensure the angular movement in flexion relative to the arm of a second segment called "forearm", the terminal end of which carries a third joint called "wrist" which is movable along three orthogonal pivot axes two by two, one of which coincides with the longitudinal axis of the forearm, said wrist being designed to receive and carry the laying head 1.

[0020] The robotic arm 5, and therefore the trajectory of the laying head 1, is controlled by an appropriate automatic control unit, of the programmable logic controller type.

[0021] The core 4 is carried by a frame 7 called the “core frame” 7 and driven in rotation around its central axis X4 relative to said core frame 7 by a suitable motorized drive device, preferably provided for this purpose with an electric motor.

[0022] Preferably, the installation 8 according to the invention, which comprises the core 4, the core frame 7 and the robotic arm 5, has several interchangeable laying heads 1, as can be seen in the figure 1 .

[0023] Each of said laying heads 1 can advantageously be supplied with a different bandage component.

[0024] The robotic arm 5 can thus select the head 2 which corresponds to the bandage component to be laid, and if necessary change the laying head 1 during a manufacturing cycle, in order to be able to successively lay several bandage components on the core 4.

[0025] The receiving face 4A of the core has, along the central axis X4, a predetermined profile 10, as illustrated in the figure 2 .

[0026] Said profile 10 corresponds to the intersection of the receiving face 4A with a cutting plane called the “meridian plane” which contains the central axis X4.

[0027] As seen on the figures 1 et 2 , the core 4 preferably has a shape of revolution around its central axis X4, and more particularly a toroidal shape, which gives the receiving face 4A a curved profile 10, here of convex curved shape, generally curved outwards.

[0028] Preferably, said profile 10 comprises a central zone that is almost flat, which corresponds to the crown 11 of the bandage that will carry the tread and will come into contact with the road, a central zone that is bordered, at each of its axial ends, by curved zones, the radius of curvature of which is included in a range of values ​​much lower than the range of values ​​of the radius(es) of curvature of the crown 11. These curved zones correspond to the shoulders 12, 13 of the bandage, that is to say to the parts of the bandage that form the transition between the crown 11 and the sides of the bandage that extend radially towards the central axis X4 to engage on a rim.

[0029] According to the invention, the method for defining a laying trajectory comprises a step (a) of geometric characterization of the profile 10, during which the outline of the profile 10 of the receiving face 4A is provided and a first set of remarkable points PP1, PP2..., PPi..., PPn-1, PPn, called "geometric remarkable points" PP1, PP2..., PPi..., PPn-1, PPn, which are considered characteristic of the shape of said profile 10, and therefore representative of the profile 10, is isolated on this profile 10, and said geometric remarkable points PP1, PP2..., PPi..., PPn-1, PPn are stored in the form of a set of trajectory points called a "trajectory table", as can be seen on the figure 2 .

[0030] The index "n" corresponds to an integer, and "i" denotes the i-th point in the series of points, the value of i being between 1 and n.

[0031] The trajectory table contains at least the spatial coordinates of said geometric remarkable points, expressed in a reference frame attached to the robotic arm 5, and more particularly attached to the fixed base 6 of said robotic arm 5, relative to which the robotic arm 5 executes the movements of the laying head 1.

[0032] It should be noted that, in absolute terms, the trajectory table, i.e. the set of trajectory points, can take any suitable form, and more precisely any suitable form of digital data storage, for example the form of a list or a table. Particularly preferably, the trajectory table will take the form of a table, where each trajectory point will form a row of said table.

[0033] In all cases, the trajectory points, and here in particular the rows of the table, will preferably be ordered in accordance with the order in which said trajectory points follow one another along the profile 10, in consideration of a given direction of travel of the profile 10, noted FWD, in which the profile 10 is traveled from one end to the other of said profile 10. In other words, the trajectory points contained in the trajectory table will preferably be ordered, in said trajectory table, in the direction of the increasing curvilinear abscissas along the profile 10.

[0034] The n geometric remarkable points PPi are therefore stored here in said trajectory table, preferably in the form of successive lines each corresponding to a remarkable point, in the order which corresponds to the direction of travel FWD.

[0035] Preferably as seen on the figure 2 , the geometric remarkable points PP1, PP2..., PPi..., PPn-1, PPn are all the closer to each other, and therefore the adjacent sections of profile 10 that said geometric remarkable points delimit two by two are all the shorter, as the radius of curvature of the profile 10 is small. Thus, more geometric remarkable points will be considered, forming a tighter network, in the strongly curved portions of the profile 10, such as the shoulders 12, 13, while said geometric remarkable points will be spaced out in the straighter portions of the profile, such as the top 11.

[0036] For information purposes, and in particular for profiles 10 which have an overall axial width W10 of between 150 mm and 370 mm, the number n of geometric remarkable points provided will preferably be between 20 and 60, more preferably between 30 and 40.

[0037] That being said, it will be noted that on the schematic example of the figures 3 and following, we will use, for simplicity of description, an intentionally shortened and simplified profile 10, on which we have identified only n=4 remarkable geometric points PP1, PP2, PP3, PP4.

[0038] According to the invention, the method for defining a laying trajectory also comprises a step (b) of functional characterization of the profile 10, during which a plurality of functional zones are determined on the profile 10, each extending from a zone start point to a zone end point, and a laying law is associated with each of said functional zones, which specifies conditions for laying the tire component 2 in the functional zone in question, and said zone start points and said zone end points are inserted, which form a second set of remarkable points PF1, PF2..., PFj..., PFm-1, PFm, called "functional remarkable points" PF1, PF2..., PFj..., PFm-1, PFm, in the trajectory table.

[0039] The index "m" corresponds to an integer, and "j" denotes the j-th point in the series of points, the value of j being between 1 and m .

[0040] Typically, up to 20, 25 or even 30 functional zones can be planned. In practice, m may be between 3 and 30, more preferably between 5 and 10.

[0041] Preferably, during step (b) of functional characterization of the profile, a laying law is associated with each of the functional zones which characterizes the laying conditions of the bandage component in the functional zone considered by specifying the value, applicable and constant in the zone considered, of at least one laying parameter, preferably of several laying parameters, and even more preferably of all the laying parameters, among: (i) the nature of the bandage component 2; for example, it is thus possible to specify whether a raw rubber strip, a reinforcing wire, or a reinforcing strip is to be laid; (ii) the laying pitch at which the laying head 1 is offset relative to the core 4 along the central axis between two successive turns; said laying pitch corresponds to the movement of the laying head along the profile per complete turn of the core, therefore to the pitch of the helix formed by the bandage component in question on the core, and it is possible, for example, to define, using this laying pitch parameter, the axial overlap rate between two consecutive turns of a rubber strip or a reinforcing strip, and thus control the radial thickness of the layer resulting from the winding of said turns; it will be noted that, in absolute terms, it would be possible to envisage axially moving the core 4 relative to the core frame 7 in order to create a relative axial movement of the core 4 relative to the laying head 1;however, the core 4 will preferably be axially fixed, and the relative axial displacement movement generated solely by the movement of the laying head 1, which will therefore make it possible to define and control said laying pitch; (iii) the laying speed which corresponds to the circumferential speed of the core 4 at which the bandage component 2 is wound onto said core; and / or (iv) the laying tension, which corresponds to the longitudinal tensile force exerted within the bandage component 2 during laying, under the tractive effect of the rotating core 4. ;

[0042] In practice, the functional remarkable points PF1, PF2..., PFj..., PFm-1, PFm will mark the limits from which, along the profile 10, the execution of a laying law begins, the execution of a laying law ends, or the transition is crossed between a first laying law and a second laying law which differs from the first laying law, and more particularly a second laying law which modifies the value of at least one of the laying parameters, or of several of the laying parameters, with respect to said first laying law which precedes it.

[0043] The laying laws will also establish, for example by specifying the laying pitch, a link between on the one hand the angular position and / or the angular speed of the core 4 relative to its central axis X4 and on the other hand the position as well as the evolution of the position of the laying head 1 along the profile 10, to allow control of the movements of the laying head 1 as a function of the angular position of the core 4.

[0044] For convenience, the laying laws, and therefore the functional remarkable points PFj which characterize them, may be initially defined in consideration of the curvilinear abscissa of the profile 10, which amounts to fictitiously considering the profile 10 in a rectilinear developed form, that is to say in the form of a fictitious straight line segment, and to fixing the functional remarkable points PFj as many markers on said fictitious straight line segment. The spatial coordinates of the functional remarkable points PFj will then be determined by performing the inverse operation, that is to say by applying the developed, carrying said points, on the real, curved path of the profile 10.

[0045] It will be noted that, in the schematic example of the figure 3 , only m = 3 functional remarkable points PF1, PF2, PF3 have been considered, here represented by dashes perpendicular to the profile, and among which the first functional remarkable point PF1 forms a starting point from which one enters a first functional zone and one begins the laying of a bandage component 2 on the core 4, in accordance with a first laying law, the second functional remarkable point PF2 indicates the entry into a second functional zone characterized by a modification of a laying parameter, for example a reduction of the laying step, so that a second laying law is applied from said second functional remarkable point PF2, and the third and last functional remarkable point PF3 indicates the arrival point where the laying operation ends, in this case at the end of the second functional zone, and therefore in accordance with the second laying law.

[0046] It will be noted that it is possible, in absolute terms, that one or more functional remarkable points PFj may coincide with one or respectively some of the geometric remarkable points PPi. However, preferably, at least a portion of the functional remarkable points PFj, where appropriate more than half of the functional remarkable points PFj, or even all of the functional remarkable points PFj, will in principle be distinct from the geometric remarkable points PPi, insofar as the definition of the laying laws and the adjustments in the successive laying laws, for example in the choice of the bandage component 2 or of the position from which laying begins, or respectively stops, said bandage component, may in practice be associated with positions on the profile 10 which do not coincide with purely geometric definition points of the profile 10.

[0047] Furthermore, if it is possible for the successive functional zones to be adjacent, so as to continuously cover the profile 10, it is also possible, in certain manufacturing cycles, to provide, between two portions of the profile 10 which must be covered by one or more tire components, a portion of the profile 10 called a "coverage interruption zone" which must not be covered by any tire component during the manufacturing cycle in question, in which case there is a corresponding interruption interval between the two functional zones which respectively precedes and immediately follows said coverage interruption zone, so that said successive functional zones are, in fact, not adjacent.

[0048] For convenience and conciseness of drafting, the plural generic expression "remarkable points" or "geometric and functional remarkable points" may be used to refer indifferently to both geometric remarkable points PPi and functional remarkable points PFj, and, more particularly, to designate any set which will group or is likely to group both geometric remarkable points PPi and functional remarkable points PFj. Similarly, the generic expression "remarkable point" or "geometric or functional remarkable point" may individually designate a remarkable point which may be indifferently, depending on the context, a geometric remarkable point PPi or a functional remarkable point PPj.

[0049] According to the invention, the method for defining a laying trajectory then comprises, after the identification of the geometric and functional remarkable points PPi, PFj, a meshing step (c) during which, in consideration of a predetermined direction of travel of the profile, noted here FWD, a series of equidistant virtual points PG1, PG2..., PGk..., PGp-1, PGp, called "potential guidance points" PG1, PG2..., PGk..., PGp-1, PGp, which delimit two by two straight line segments all having an identical length, equal to a predetermined chosen value, called "unit resolution step" is defined on the profile 10. P_unit, as illustrated in the figure 4 , and the said potential guidance points PG1, PG2..., PGk..., PGp-1, PGp are inserted into the trajectory table.

[0050] The subscript "p" corresponds to an integer, and "k" denotes the kth point in the series of points.

[0051] Preferably, the value of the unit resolution step P_unit which separates two by two the potential guide points PG1, PG2..., PGk..., PGp-1, PGp created during the meshing step (c) is between 0.1 mm and 1 mm, for example equal to 0.5 mm.

[0052] Such a value will in fact make it possible to obtain a sufficiently fine resolution, and therefore sufficient precision, in the geometrically most complex portions of profile 10, and / or in the most difficult functional zones, and therefore even more so in the simpler portions of profile 10. This value will therefore correspond to the optimum precision that the process can offer.

[0053] As an indication, taking into account the developed length of profile 10 and the unit resolution step P_unit envisaged, the initial number of potential guidance points resulting from the “raw” meshing operation, i.e. the number p, could be between 500 (five hundred) and 8,000 (eight thousand), for example between 2,000 and 5,000.

[0054] At this stage, at the end of meshing step (c), we therefore obtain in any case a “raw” trajectory table, which temporarily contains the set of geometric remarkable points PPi, the set of functional remarkable points PFj, and the set of potential guidance points PGk.

[0055] As an indication, the raw trajectory table can thus have at least 500 points, at least 1,000 (one thousand) points, or even at least 2,000 (two thousand) points, and sometimes up to 8,000 (eight thousand) trajectory points.

[0056] As mentioned above, however, it is not necessary, in practice, to maintain this initial homogeneous mesh over the entire profile 10, the mesh of which, very fine, is equal to, or even locally smaller than, the unit resolution step P_unit. It is in fact possible to use a less fine resolution, and therefore a larger step, in the portions of profile 10 in which the direction of profile 10 and the laying law vary little or not at all, as long as no notable change affects the layout of profile 10 or the laying law.

[0057] Among all the potential guidance points PGk initially available, provisionally inserted into the trajectory table, and more generally among all the potential guidance points PGk and the remarkable geometric points PPi and functional points PFj present in the trajectory table and therefore forming as many available trajectory points, some will consequently actually be retained to be part of the final simplified trajectory table 20, others not, depending on their usefulness.

[0058] This is why, according to the invention, the method for defining a pose trajectory then comprises, after the meshing step (c), a simplification step (d) during which the size of the trajectory table is reduced by applying to the trajectory table one or more selection criteria in order to select at least a part, and only a part, of the potential guidance points PGk and the geometric and functional remarkable points PPi, PFj contained in the trajectory table, and by eliminating the unselected points, so as to obtain, as can be seen on the figure 10 , a simplified trajectory table 20, of reduced size, within which at least one and preferably several of the (straight) segments which connect two by two the successive selected points have a length strictly greater than the unit resolution step P_unit chosen.

[0059] It should be noted that, in practice, the trajectory points will be retained, and more particularly the potential guidance points PGk, which correspond to singularities of the profile 10 or of the pose law, in order to concentrate the precision, and therefore the available computing power, in the portions of the profile 10 which truly require it.

[0060] From a formal point of view, the application of each selection criterion can be considered as a sub-step of step (d) of simplification.

[0061] By convention and convenience of representation, the potential guidance points PGk appear dotted on the figures 3 à 10 , and the points actually selected, and therefore present in the trajectory table at the time considered, are indicated by small circles in a continuous line with a hollow central part. Arrows indicate the points which are added to the selection (also called "list of selected points") during the sub-step considered, depending on the selection criterion applied.

[0062] Preferably, during the simplification step (d), one, in this case a first, selection criterion by framing, is applied, according to which, as is visible on the figure 5 , we select the first functional remarkable point PF1, considered as the starting point Pstart of the laying trajectory, we select the last functional remarkable point PFm, considered as the arrival point Pend of the laying trajectory, and, for at least one geometric or functional point PPi, PFj which is strictly between the starting point Pstart and the arrival point Pend, and more preferably for each geometric or functional remarkable point PPi, PFj which is strictly between the starting point Pstart and the arrival point Pend, namely here in this order PF2, PP2 then PP3 on the example of the figure 5 , we select, from among the two potential guidance points PGk which frame said remarkable geometric or functional point PPi, PFj, that is to say from among the potential guidance point which immediately precedes and the potential guidance point which immediately follows said remarkable geometric or functional point PPi, PFj, at least one of said two potential guidance points PGk, for example that of said two guidance points PGk which is closest to the remarkable geometric or functional point PPi, PFj considered.

[0063] More preferably, for at least one or respectively for each remarkable point PPi, PFj which is strictly between the starting point Pstart and the arrival point Pend, we select each of the two potential guidance points PGk which frame the geometric or functional remarkable point PPi, PFj considered, that is to say which for one immediately precedes and for the other immediately follows said geometric or functional remarkable point PPi, PFj.

[0064] On the figure 5 , this amounts to selecting PG5, PG6, which frame PF2, then PG12 and PG13, which frame PP2, then PG21 and PG22 which frame PP3.

[0065] It will thus be possible to obtain a precise and balanced smoothing of the portions of the profile in which the remarkable points PPi, PFj are located, by selecting the two potential guidance points PGk which are located on either side of the remarkable point PPi, PFj considered along the profile 10.

[0066] Such a selection will advantageously make it possible, without inducing any significant error in the tracking of the profile 10 and the laying laws, to substitute said remarkable point PPi, PFj by the corresponding pair of potential guidance points PGk.

[0067] In this respect, it will be noted that, preferably, after having selected, in accordance with the selection criterion by framing, the or preferably the potential guidance points PGk which frame a remarkable geometric or functional point PPi, PFj strictly between the starting point Pstart and the arrival point Pend, the remarkable geometric and functional point PPi, PFj concerned is deleted.

[0068] More preferably, all the geometric and functional remarkable points PPi, PFj strictly included between the starting point Pstart and the arrival point Pend will be the subject of a framework by one or preferably by two potential guidance points PGk according to this first selection criterion, so that we will thus be led to delete all said geometric and functional remarkable points PPi, PFj strictly included between the starting point Pstart and the arrival point Pend.

[0069] The aforementioned deletion amounts to "de-selecting" all the remarkable points PPi, PFj which are concerned by the selection criterion by framing, and therefore to deleting from the trajectory table at least part of, and preferably all of, the geometric and functional remarkable points PPi, PFj which are strictly included between the starting point Pstart and the arrival point Pend.

[0070] Such a deletion operation is advantageously made possible by the fact that the potential guidance point or, even more so, the two potential guidance points PGk selected in the vicinity of each geometric or functional remarkable point PPi, PFj concerned are chosen from the two potential guidance points PGk which frame said remarkable point PPi, PFj and which are both located at a very short distance from said remarkable point, in this case at a distance which is strictly less than the unit resolution step P_unit, so that it is not useful to keep the remarkable point PPi, PFj to satisfy the desired precision requirement.Indeed, once the potential guidance point(s) PGk have been selected in this way, the remarkable geometric or functional point PPi, PFj which is at the origin of this selection becomes in fact redundant with regard to the definition of the laying trajectory, and can therefore be deleted without risk of distorting the trajectory or a laying law.

[0071] This removal of the remarkable points PPi, PFj thus “framed” by potential guidance points PGk also makes it possible, by imposing a minimum separation step between two successive points, in this case by imposing a minimum distance equal to the unit resolution step P_unit between two potential guidance points PGk thus selected, to guarantee that the control unit, and more particularly the computer controlling the robotic arm 5, will be able to perceive in time, with regard to its refresh rate, all the points of the trajectory table, used as successive setpoints, when the laying head 1 is in motion, so that the control of the robotic arm 5 will not be disturbed by too great a proximity between two points.

[0072] The deletion of the remarkable points PPi, PFj framed by selected potential guidance points PGk is preferably immediate, so that said remarkable points PPi, PFj no longer participate as such in the subsequent selection of the trajectory points when applying the selection criteria which follow the application of the selection criterion by framing.

[0073] Furthermore, as it is rare for the last functional remarkable point PFm to coincide exactly with one of the virtual guidance points PGk, and that in addition it is desirable to ensure the precision of the end of the laying operation, in particular in order to avoid a possible overshoot of the setpoint or an excessively abrupt slowing down of the laying head 1, it will also be preferable to select, still according to this same framing criterion, the virtual guidance point PGk which immediately precedes the last functional remarkable point PFm, here therefore PG29 on the figure 5 , while also retaining, as indicated above, the said last functional remarkable point PFm, which constitutes the arrival point Pend.

[0074] Preferably, during the simplification step (d), and more preferably following the application of the first selection criterion by framing described above, a, here a second, selection criterion is applied, namely a selection criterion by authorized deviation limit, according to which we consider, for each pair of adjacent straight line segments defined by each trio of successive points already selected, for example the trio PG13, PG21, PG22 on the figures 5 à 7 , the interpolating circle Ck which passes through the three points of said trio, and, for each of the two straight line segments 21 delimited by two successive points of said trio of points, we calculate the arrow D between said straight line segment 21, forming the chord of the arc 21, and the arc 22 of the interpolating circle which corresponds to it, that is to say the greatest distance D measured perpendicular to the straight line segment 21 and which separates the arc 22 from said straight line segment 21, as illustrated in the figure 6 , and, if said arrow D calculated for said segment 21 exceeds a predefined maximum authorized deviation value Dmax, the intermediate potential guidance point PGk, or one of the intermediate potential guidance points PGk, which are located between the potential guidance points forming the ends of the segment 21 considered, is added to the list of selected points, as can be seen on the figures 6 And 7 .

[0075] Preferably, the potential guidance point PGk which is located closest to the middle of the line segment 21 concerned is added to the list of selected points.

[0076] In the example of the figures 6 And 7 , this is the potential guidance point PG17.

[0077] Advantageously, it is thus possible to add a trajectory point, and therefore bring the corresponding deviation back to zero, precisely at the place, or at least close to the place, where the deviation between the interpolating circular arc 22 and the arc chord segment 21 is initially the greatest.

[0078] Of course, after adding a point to the selection, we can repeat the application of the selection criterion by authorized deviation limit in order to ensure that the new division into segments integrating the added points satisfies said criterion, and if necessary proceed to a new addition of point to guarantee sufficient proximity between the segments (arc chords) and the interpolating circles.

[0079] Thus, it will be ensured that the trajectory formed by the broken line made up of all the selected points, and therefore by the succession of adjacent straight line segments which link these selected points two by two, will always pass sufficiently close to the actual path of profile 10, and will therefore constitute an acceptable approximation of said profile 10.

[0080] Preferably, the maximum permitted deviation value Dmax will be chosen equal to a quarter of the unit resolution step: Dmax = P_unit / 4

[0081] This will allow the segmented trajectory to never deviate significantly from profile 10.

[0082] Preferably, during the simplification step (d), and more preferably after the application of the second selection criterion by authorized deviation limit, a, here a third, selection criterion is applied, namely a selection criterion by maximum authorized segment length, according to which, as is visible on the figure 8 , we calculate the length L21 of each straight line segment 21 having as its ends two successive already selected points and, if said calculated length L21 exceeds a predefined maximum authorized length value Lmax, we add to the list of selected points one of the potential guide points PGk which are strictly between the two points forming the ends of the segment 21 considered, as can be seen on the figure 8 .

[0083] On the example of the figure 8 , the two segments 21 which initially exceed the maximum permitted length Lmax are the segment joining PG6 to PG12, and the segment joining PG22 to PG29. This leads to the addition of PG11 and PG27 respectively to the selection.

[0084] Preferably, in accordance with this third selection criterion by maximum authorized segment length, either the potential guidance point PGk which forms with the potential guidance point PGk forming the start end of the segment 21 concerned the largest segment whose length remains less than or equal to the maximum authorized length value Lmax, as can be seen on the figure 8 , or, alternatively, the potential guidance point PGk which is located closest to the middle of the line segment 21 concerned.

[0085] Here again, we can of course repeat this third length limitation criterion as many times as necessary to arrive at a trajectory in which all the segments satisfy said third criterion, i.e. all have a length less than or equal to the maximum authorized length Lmax.

[0086] By limiting the maximum permissible length for the segments, i.e. the “free flight” value of the laying head 1, we avoid making the laying head 1 travel too great a distance blindly, and we thus avoid in particular the risks or consequences of a possible overshoot or a possible drift of the actual trajectory of the laying head 1 in relation to the trajectory specified by the segments of the trajectory table and, more generally, in relation to profile 10.

[0087] The maximum permitted length value Lmax may be set as a distance, or possibly, in a substantially equivalent manner, as the maximum permitted number of potential guidance points not yet selected present between two points already selected, i.e. as the size of the “empty” mesh space between two points already selected.

[0088] As an indication, the maximum authorized length Lmax chosen may be between 10 mm and 50 mm.

[0089] Preferably, during the simplification step (d), and more preferably after having applied the different selection criteria described above, one, here a fourth, selection criterion is applied, namely a selection criterion by degree of quality, according to which one adds to the points already selected the N potential guidance points which immediately precede and the N potential guidance points which immediately follow each of said points already selected, N being an integer, preferably equal to zero by default, the value of which is set by the user.

[0090] The value of N will preferably be adjusted empirically, and more particularly increased, for example brought to the value 1 or 2, preferably as a function of a test during which a bandage is manufactured using the simplified trajectory table obtained following the application of the preceding criterion(s), here the first, second and third selection criteria, then the quality of the bandage obtained is evaluated and, if said quality is deemed insufficient, the value N is increased by one unit.

[0091] This selection criterion by degree of quality will advantageously improve the quality of the finish, in particular the appearance of the bandage and the quality of the junction between successive turns, in particular in the portions of the profile 30 which are affected by changes of direction (turns).

[0092] In species, if we choose N = 1, as in the example illustrated on the figure 9 , then we add to the trajectory table any potential guidance point PGk which is immediately adjacent to a point which will have already been previously selected, here in application of one of the first, second and third selection criteria mentioned above.

[0093] Here, this will therefore amount to adding to the selection the potential guide points PG2, PG4, PG7, PG10, PG14, PG16, PG18, PG20, PG23, PG26 and PG28.

[0094] All points that have not been selected after applying the selection criterion(s) are then eliminated. In particular, at least all potential guidance points PGk that have not been selected are thus deleted, and preferably both the potential guidance points PGk that have not been selected and the remarkable points, geometric PPi and functional PFj, that have not been selected.

[0095] Ultimately, we therefore obtain a simplified trajectory table 20, as illustrated in the figure 10 , where only a part of the remarkable points PPi, PFj and, above all, of the potential guidance points PGk, have been retained, and more particularly here within which only the first and last functional remarkable points PF1, PFm = PF3 on the one hand, and a part of the potential guidance points on the other hand, as they have been identified by the first, second, third and fourth selection criteria above, applied in this order, have been retained as definitive trajectory points.

[0096] In the example of the figures 3 à 10 , we will thus have retained, in addition to the functional remarkable points PF1 = Pstart and PF3 = Pend, the following series of potential guidance points: PG1 (which by definition merges with PF1) to PG2, PG4 to PG7, PG10 to PG14, PG16 to PG18, PG20 to PG23, and PG26 to PG29, which immediately precedes PF3.

[0097] The "holes" which separate the said series of points from one another form as many reliefs of the trajectory table.

[0098] For information purposes, it will be noted that the number of trajectory points finally selected, and therefore the total number of trajectory points stored, in the form of table lines, in the simplified trajectory table 20, is preferably between 150 (one hundred and fifty) points and 1,000 (one thousand) points.

[0099] In any event, the reduction ratio, which is equal to the ratio between the size of the simplified trajectory table 20 obtained after application of the selection criteria and the size of the “raw” trajectory table resulting from the meshing step (c), i.e. the ratio between the number of trajectory points finally selected and therefore contained in the simplified trajectory table 20 on the one hand and the maximum potential number of trajectory points represented by the sum of all the remarkable points PPi, PFj and all the potential guidance points Gk initially available at the end of the raw meshing step (c) on the other hand, is preferably substantially between 1 / 10 and 1 / 30, i.e. a reduction in the size of the trajectory table by a factor of 10, 20, or even 30.

[0100] The method according to the invention is therefore particularly effective in reducing the control of the laying head 1 while maintaining excellent control of the laying trajectory.

[0101] Of course, the invention relates as such to a method of manufacturing a bandage during which a simplified trajectory table 20 is established in accordance with a trajectory definition method according to any one of the possibilities described above, and the simplified trajectory table 20 is transmitted to a robotic arm 5 carrying the laying head 1, so that said robotic arm 5 executes said simplified trajectory table 20 using as instructions the succession of segments which connect the successive selected points stored in said simplified trajectory table 20.

[0102] Preferably, the simplified trajectory table 20 associates each of its selected points with an absolute rotation angle of the core 4, and during the rotation of the core 4 around its central axis X4, the absolute rotation angle traveled in rotation by said core 4 from a predefined origin is measured, and the position conferred by the robotic arm 5 to the laying head 1 is slaved to the rotation angle of the core.

[0103] The simplified trajectory table 20 may advantageously be presented for this purpose in the form of a table comprising the points stored in the form of lines and whose input value, typically the value stored in the first column of each line, will indicate the rotation angle corresponding to the point considered.

[0104] The angular position of the core can be encoded by any suitable sensor associated with the central axis X4, such as a resolver type encoder.

[0105] Each line will preferably include the target coordinates (X, Y, Z) of the laying head 1 expressed in each of the three axes of the Cartesian reference frame (X5, Y5, Z5) attached to the base 6 of the robotic arm 5, as well as, where appropriate, the angular orientation (W, P, R) of the laying head 1 in yaw, roll, and possibly pitch, in said reference frame.

[0106] By convention, the "roll" will allow the laying head to tilt laterally (here around the axis Y4, with which the axis Y5 merges) to remain tangent to the curvature of the profile 10 such that this curvature is drawn in a meridian plane containing the central axis X4 and passing through the point of contact between the laying head 1 and the receiving face 4A of the core 4, while the "yaw" will correspond to the rotation around the axis (here radial, and more particularly vertical) which is normal to the receiving face 4A at the point of contact between the laying head 1 and said receiving face 4A, and will allow the bandage component 2 to be oriented so that the longitudinal direction of said bandage component 2 coincides with the direction formed by the desired helix angle for the winding relative to the circumferential direction of the core 4.

[0107] Thus, one can for example proceed as follows: The control unit, establishes, in accordance with the trajectory definition method described above, a simplified trajectory table 20, then transmits the simplified trajectory table 20 to the robotic arm 5, and requests said robotic arm 5 to execute the tracking of the points contained in said simplified trajectory table 20. It will be noted that, as indicated previously, the robotic arm 5 has a summary intelligence, that is to say its own means of calculation and data storage, existing but limited, which allow it to execute, in the form of linear segments, a point-to-point instruction tracking provided in the form of a trajectory table.

[0108] The control unit having calculated the angular position of the core 4 which must be reached to begin the laying operation, that is to say the angular position which corresponds to the starting point Pstart of the first functional zone, said control unit starts the rotation of the core 4.

[0109] At a determined refresh rate, the robotic arm 5 reads the angular position of the core 4 using the encoder.

[0110] Depending on this feedback on the angular position of the core 4, the robotic arm 5 searches in the simplified trajectory table 20 for the line at which it is located, and therefore the setpoint coordinates applicable at the instant in question.

[0111] Once said line has been identified, the robotic arm 5 reads, in its own reference system (X5, Y5, Z5), the coordinates X, Y, Z, W, P and R which correspond to its effective position, and more particularly to the effective position and orientation of the laying head 1.

[0112] The robotic arm 5 then determines, by comparing the setpoint coordinates provided by the line of the simplified trajectory table 20 on the one hand with the coordinates of its own effective position on the other hand, what distance (linear on the X5, Y5, Z5 positioning axes, angular for the orientation rotations in roll, yaw, or even pitch) it must travel to reach the X, Y, Z, W, P and R coordinates entered in the simplified trajectory table.

[0113] The robotic arm 5 then executes a linear movement to reach the setpoint coordinates, i.e. to reach the trajectory point specified in the simplified trajectory table, and therefore place the laying head 1 in the desired configuration.

[0114] This cycle starts again until the core 4 reaches the calculated final angular position, i.e. the arrival point Pend of the pose trajectory, at the end of the last functional zone, and the robotic arm 5 consequently reaches the last point (here the last line) of its simplified trajectory table 20.

[0115] Furthermore, according to a preferred characteristic which may constitute an invention in its own right, the manufacturing method may comprise, preferably prior to the execution of the simplified trajectory table 20, and more generally prior to the execution of any trajectory table, a calibration step during which, by means of a laser tacheometer mounted on a station which is located at a chosen reference location, and which is distinct from the frame 7 called the “core frame” 7 which carries the core 4 and the device for driving said core 4 in rotation, and which is also distinct from the base 6 of the robotic arm 5, the position of three target points of the core frame 7 is measured, in order to identify a first Cartesian reference frame (X4, Y4, Z4), called the “core reference frame”, attached to the core frame, relative to the location of the laser tacheometer station, then a target, such as a corner cube, is fixed,at the location of the robotic arm 5 intended to receive the laying head 1, here therefore on the wrist, then the robotic arm 5 is moved so as to successively position said target at three different points in space, and the position of said target is measured each time so as to identify, relative to the same location of the laser tacheometer station, a second Cartesian reference frame (X5, Y5, Z5), called the “robot reference frame”, attached to the robotic arm 5, and more precisely to the fixed base 6 of said robotic arm 5, and the robotic arm 5 is calibrated so as to superimpose the robot reference frame (X5, Y5, Z5) with the core reference frame (X4, Y4, Z4), and thus make the orthonormal axes of said reference frames coincide: X4 with X5, Y4 with Y5, Z4 with Z5.

Claims

1. Method for controlling a laying head (1), said laying head being intended for laying at least one tyre component (2) by winding said tyre component (2) in turns on a receiving face (4A) of a core (4) rotated about its central axis (X4), said receiving face (4A) having, along said central axis, a predetermined profile (10), said method being characterized in that it comprises: - a step (a) of geometric characterization of the profile, during which the outline of the profile (10) of the receiving face (4A) is provided and a first set of remarkable points, referred to as "geometric remarkable points" (PP1, PP2..., PPi..., PPn-1, PPn), are isolated on this profile, these points being considered to be characteristic of the shape of said profile (10), and said geometric remarkable points (PP1, PP2..., PPi..., PPn-1, PPn) are stored in the form of a set of path points referred to as the "path chart", - a step (b) of functional characterization of the profile, during which a plurality of functional zones is determined on the profile, each of which extends from a zone start point to a zone end point, and a laying law is associated with each of said functional zones, which laying law specifies conditions for laying the tyre component in the functional zone in question, and said zone start points and said zone end points, forming a second set of remarkable points referred to as "functional remarkable points" (PF1, PF2..., PFj..., PFm-1, PFm), are inserted in the path chart, - then a step (c) of meshing during which, with reference to a predetermined direction of travel (FWD) of the profile, a series of equidistant virtual points (PG1, PG2..., PGk..., PGp-1, PGp), referred to as "potential guide points" (PG1, PG2..., PGk..., PGp-1, PGp), which delimit in pairs line segments all having an identical length, equal to a predetermined chosen value, referred to as the "unit resolution pitch" (P_unit), are defined on the profile (10), from the first functional remarkable point (PF1), that is to say from the point at which the first functional zone begins, considered the origin, to the last functional remarkable point (PFm), that is to say to the point at which the last functional zone ends, and said potential guide points are inserted in the path chart, - then a step (d) of simplification during which the size of the path chart is reduced by applying to the path chart one or more selection criteria in order to select at least some, and only some, of the potential guide points (PGk) and geometric and functional remarkable points (PPi, PFj) contained in the path chart, and by deleting the points not selected, in such a way as to obtain a simplified path chart (20), of reduced size, within which at least one, and preferably several, of the segments which connect the successive selected points in pairs have a length strictly greater than the chosen unit resolution pitch (P_unit).

2. Method according to Claim 1, characterized in that during the simplification step (d), a selection criterion is applied, based on flanking, according to which the first functional remarkable point (PF1) is selected, this being considered the start point (Pstart) of the laying path, the last functional remarkable point (PFm) is selected, this being considered the arrival point (Pend) of the laying path and, for at least one, and preferably for each, geometric or functional remarkable point (PPi, PFj) which is strictly between the start point (Pstart) and the arrival point (Pend), out of the two potential guide points (PGk) which flank said geometric or functional remarkable point (PPi, PFj), that is to say out of the potential guide point which immediately precedes and the potential guide point which immediately follows said geometric or functional remarkable point (PPi, PFj), at least one of said two potential guide points (PGk) is selected, for example the one out of said two guide points (PGk) which is closest to the geometric or functional remarkable point (PPi, PFj) in question.

3. Method according to Claim 2, characterized in that, for the at least one or respectively for each geometric or functional remarkable point (PPi, PFj) which is strictly between the start point (Pstart) and the arrival point (Pend), each of the two potential guide points (PGk) which flank, that is to say which in the case of one of them immediately precedes and for the other immediately follows said geometric or functional remarkable point (PPi, PFj), is selected.

4. Method according to Claim 2 or Claim 3, characterized in that after having selected, in accordance with the flanking selection criterion, the potential guide point or points (PGk) flanking a geometric or functional remarkable point (PPi, PFj) strictly between the start point (Pstart) and the arrival point (Pend), the geometric and functional remarkable point (PPi, PFj) in question is deleted.

5. Method according to one of the preceding claims, characterized in that, during the simplification step (d), a selection criterion based on an authorized deviation limit is applied, according to which account is taken, for each pair of adjacent line segments defined by each trio of successive points already selected, of the interpolation circle (Ck) which passes through the three points of said trio and, for each of the two line segments (21) delimited by two successive points of said trio of points, the deflection (D) is calculated between said line segment (21), forming an arc chord, and the arc (22) of the interpolation circle which corresponds to it and, if said deflection (D) calculated for said segment (21) exceeds a predefined maximum authorized deviation value (Dmax), the intermediate potential guide point or one of the intermediate potential guide points (PGk) located between the potential guide points forming the ends of the segment (21) in question, preferably the potential guide point (PGk) located closest to the middle of the line segment (21) in question, is added to the list of selected points.

6. Method according to one of the preceding claims, characterized in that, during the simplification step (d), a selection criterion based on a maximum authorized segment length is applied, according to which the length (L21) of each line segment (21) having two successive points already selected as its ends is calculated and, if said calculated length (L21) exceeds a predefined maximum authorized length value (Lmax), one of the potential guide points (PGk) located strictly between the two points forming the ends of the segment (21) in question, preferably either the potential guide point (PGk) which forms with the potential guide point forming the start end of the segment in question the largest segment having a length less than or equal to the maximum authorized length value (Lmax), or the potential guide point (PGk) located closest to the middle of the line segment (21) in question, is added to the list of selected points.

7. Method according to one of the preceding claims, characterized in that, during the simplification step (d), a selection criterion based on level of quality is applied, according to which the N potential guide points (PGk) which immediately precede and the N potential guide points (PGk) which immediately follow each of said points already selected are added to the points already selected, N being an integer, preferably zero by default, the value of which is set by the user, wherein said value of N may preferably be adjusted empirically, and more particularly increased, for example brought to the value 1 or 2, preferably on the basis of a test in which a tyre is manufactured using the simplified path chart obtained following the application of the preceding criterion or criteria, the quality of the tyre obtained is assessed and, if said quality is deemed insufficient, the value N is incremented by one unit.

8. Method according to one of the preceding claims, characterized in that the value of the unit resolution pitch (P _unit) which separates, in pairs, the potential guide points (PG1, PG2..., PGk..., PGp-1, PGp) created during the meshing step (c) is between 0.1 mm and 1 mm, for example equal to 0.5 mm.

9. Method according to one of the preceding claims, characterized in that during the step (b) of functional characterization of the profile, a laying law is associated with each of the functional zones, which laying law characterizes the conditions for laying the tyre component (2) in the functional zone in question by specifying the value, applicable and constant in the zone in question, of at least one laying parameter, and preferably of several laying parameters, from among: (i) the nature of the tyre component, (ii) the laying pitch according to which the laying head (1) is offset with respect to the core (4) along the central axis (X4) between two successive turns, (iii) the laying speed, which corresponds to the circumferential speed of the core (4) at which the tyre component (2) is wound on said core, and / or (iv) the laying tension, which corresponds to the longitudinal tensile force exerted within the tyre component (2) during laying, under the traction effect of the core (4) in rotation.

10. Method for manufacturing a tyre during which a simplified path chart (20) is established in accordance with the method for controlling a laying head according to any one of Claims 1 to 9, and the simplified path chart (20) is transmitted to a robotic arm (5) carrying the laying head (1), such that said robotic arm (5) executes said simplified path chart (20) using as setpoint the succession of segments which connect the successive selected points stored in said simplified path chart.

11. Method for manufacturing a tyre according to Claim 10, characterized in that the simplified path chart (20) associates each of its selected points with an absolute angle of rotation of the core, in that during the rotation of the core (4) about its central axis (X4), the absolute angle of rotation travelled in rotation by said core from a predefined origin is measured, and in that the position given by the robotic arm (5) to the laying head (1) is slaved to the angle of rotation of the core.

12. Method for manufacturing a tyre according to Claim 10 or 11, characterized in that it comprises a calibration step during which, using a laser tacheometer mounted on a station which is located at a chosen reference location, and which is separate from the frame (7) referred to as the "core frame" (7) which carries the core (4) and the device for rotating said core, and separate from the base (6) of the robotic arm (5), the position of three target points on the core frame is measured in order to identify a first Cartesian frame of reference (X4, Y4, Z4), referred to as the "core frame of reference", attached to the core frame (7), with respect to the location of the laser tacheometer station, and then a target, such as a corner cube, is fixed at the location of the robotic arm (5) intended to receive the laying head (1), the robotic arm (5) is moved in such a way as to successively position said target at three different points in space, and the position of said target is measured each time so as to identify, with respect to the same location of the laser tacheometer station, a second Cartesian frame of reference (X5, Y5, Z5), referred to as the "robot frame of reference", attached to the robotic arm (5), and the robotic arm (5) is calibrated in such a way as to superimpose the robot frame of reference (X5, Y5, Z5) with the core frame of reference (X4, Y4, Z4), and thus make the orthonormal axes of said frames of reference coincide.