CH716882B1 - Process for adjusting the oscillation frequency of a balance-spring oscillator. - Google Patents

Abstract

The invention relates to a method for adjusting the frequency of oscillation of an oscillator (11) balance wheel (11a) - hairspring (11b) of a timepiece movement (5), said movement (5) being mounted on a support (3) and having a known rate delay intended to be modified by removal of material from said balance wheel (11a) in at least one predetermined zone, the method comprising the following steps, carried out with the oscillator in an oscillating state: a ) performing measurements of the angular position of said pendulum (11a) over at least a first half cycle; b) comparing said measurements with a mathematical model to determine the frequency, phase and amplitude of said pendulum (11a); c) based on said mathematical model and said measurements, modeling the angular displacement of said pendulum (11a) during a second half cycle which directly follows said first cycle; d) controlling a laser (17) to ablate material from said rocker arm (11a) in said at least one predetermined zone during said second half-wave based on the modeling of step c).

Description

Technical area

The present invention relates to the field of watchmaking. It relates, more particularly, to a method for adjusting the oscillation frequency of a balance-spring oscillator of a watch movement.

State of the art

[0002] The mechanical regulating member most commonly used in mechanical watchmaking is the balance-spring oscillator, which comprises an inertial mass, called a “balance wheel”, mounted in rotation around an axis. The balance wheel is subjected to a return force supplied by a spiral spring, the inner end of which is integral with said axis and the outer end of which is fixed to a frame element. By these means, the balance wheel is arranged to oscillate around a neutral position when it is sustained by an escapement under the effect of a driving force. The precise adjustment of the oscillation frequency of the regulating organ of a watch movement is necessary so that its rate, i.e. the advance or the delay taken in 24 hours compared to a reference standard, is as close as possible to 0 s/d.

[0003] Various solutions have been developed over the last few centuries in order to adjust the frequency of this type of oscillator by acting either on the effective length (and therefore on the effective stiffness) of the spiral spring by means of a racket or similar, or on the inertia of the balance by providing adjustable weights. The latter are typically screws mounted radially in the rim of the balance, the watchmaker being able to adjust the inertia by screwing or unscrewing the screws, which modifies the inertia and the balance of the balance. Of course, these two adjustment means can be used in combination.

[0004] These adjustments are difficult to perform precisely, in particular with regard to the adjustment of weights, which requires meticulous and time-consuming work by a qualified watchmaker.

[0005] The document CH609196 discloses a dynamic adjustment of the frequency of a balance-spring oscillator already mounted in its movement. The oscillator is preset to present a slight delay and the rim of the balance has a thin veil which is pierced by a laser after taking measurements to determine the number of holes to be pierced. The operator enters on the machine the number of holes to be drilled on the basis of the previous determination and the laser is controlled to drill them automatically, by synchronizing the shots and the position of the pendulum determined by an optical device. However, this process is basic and not automated. Therefore, it is inefficient and requires a skilled operator. It is therefore likely to be optimized, in particular in terms of the precision of the placement of the holes.

[0006] The document CH704693 discloses several hypothetical methods for adjusting and balancing a balance wheel, which are also likely to be optimized.

The object of the invention is therefore to provide a method for adjusting a balance-spring oscillator of a watch movement in which the aforementioned defects are at least partially overcome.

Disclosure of Invention

More specifically, the invention relates to a method for adjusting the frequency of oscillation of a balance-spring oscillator of a timepiece movement, as defined by claim 1. The movement, which comprises in known manner, a driving source driving an escapement arranged to maintain said oscillator, is mounted on a support and has a known running delay, measured beforehand by ad hoc means. With the aim of at least partially correcting this delay, one or more areas to be ablated on the surface of the balance wheel are predetermined. This correction can be determined to approach, or even to reach, a rate value close to zero or another value intended to be compensated by another element of the movement.

The method comprises the following steps, carried out with the oscillator in a state of oscillation:

a) perform a plurality of measurements of the angular position of said balance on at least a first half-wave, which is preferably a rising half-wave extending from its neutral position of the balance to its cusp position. These measurements can be carried out for example by means of a measuring device comprising a high-speed digital camera and/or a laser sensor (conventional or Doppler effect) and/or a chromatic confocal sensor and/or an interferometric sensor and /or an acoustic sensor and/or a magnetic or similar sensor;

b) comparing said measurements with a mathematical model in order to determine the frequency, phase and amplitude of said pendulum on the basis of said measurements as well as said mathematical model;

c) based on said mathematical model and said measurements, modeling the angular displacement of said balance during a second half-wave which directly follows said first half-wave;

[0013] d) controlling a laser (17) to ablate material from said rocker arm (11a) in said at least one predetermined zone, during said second half-cycle based on the modeling of step c).

[0014] Steps a) to d) can be repeated as many times as necessary in order to obtain the desired setting.

[0015] In doing so, the laser shots can be performed at the right times so that the predetermined zone(s) are correctly ablated at the desired locations. Advantageously, there is no disturbance linked to the escapement between the first half-cycle where the measurements are taken, and the second half-cycle where the shots are taken. The precision of the ablation is thus significantly improved compared to the prior art, while providing a method which is simple and quick to implement, and which is carried out completely automatically.

[0016] Advantageously, during step a), the amplitude of said balance wheel is determined either for certain alternations, or for each alternation.

[0017] Alternatively, the beam of said laser is fixed relative to the support, which is simple to implement. In such a case, the firing rate of said laser can be adapted to the angular speed of the pendulum during firing, this adaptation being determined on the basis of predictions arising from said modeling of step c). This adaptation can be performed either continuously or by being determined for each of a plurality of angular sectors. These two possibilities make it possible to guarantee that the ablated zones are exposed to the laser beam in a substantially uniform manner.

[0018] In another variant, said laser beam can be moved along at least one axis so that its spot can be moved on the surface of the balance wheel, regardless of the surface of the latter intended to be ablated (outer wall, face upper or lower face). In such a case, the scanning speed of said laser can be adapted to the angular speed of the pendulum when firing the laser, again on the basis of predictions arising from said modeling, either continuously or by being determined for each d a plurality of predetermined angular sectors of the pendulum. This also ensures that the ablated areas are exposed to the laser beam evenly.

[0019] Independently of whether said beam is scannable in order to be able to follow the movement of the surface of the pendulum or not, said laser beam can also be scanned in another direction in order to ablate material in patterns which are wider. than the size of the laser spot on the pendulum. Furthermore, the focus of the laser beam and/or its energy can be dynamically adapted.

[0020] Advantageously, the at least one ablated zone can be checked by means of a chromatic confocal sensor or a high-speed digital camera, after ablation, in order to check its position, its dimensions, etc.

Advantageously, the laser beam is directed towards an outer wall of the balance, preferably lateral, so that said beam extends substantially in the plane of the latter, preferably radially relative to the axis of the balance.

The invention also relates to a system for adjusting the frequency of a regulating member of a watch movement, comprising:

[0023] - a support adapted to receive a watch movement comprising a balance-spring regulating member;

[0024] - an ablation laser adapted to direct its laser beam towards said pendulum when a movement is mounted on the support;

[0025] - a measuring device adapted to measure the displacements of said pendulum when a movement is mounted on the support;

[0026] - a controller adapted to receive signals from said measuring device and to control the firing of said laser in order to ablate material from said pendulum in at least one predetermined zone, according to the method of one of the preceding claims.

Advantageously, said measuring device comprises a high-speed digital camera and/or a laser sensor (conventional or Doppler effect) and/or a confocal chromatic sensor and/or an interferometric sensor and/or an acoustic sensor and/or or a magnetic sensor.

[0028] Advantageously, said laser is arranged to direct its beam in a radial direction with respect to said pendulum.

Advantageously, said system further comprises a chromatic confocal sensor and/or a high-speed digital camera arranged to take measurements of said at least one predetermined zone. This sensor can be the same sensor as said measuring device, or an additional sensor, and allows verification of the ablation performed.

Brief description of the drawings

Other details of the invention will appear more clearly on reading the description which follows, given with reference to the appended drawings in which: Figure 1 is a schematic view of a system 1 suitable for carrying out the method according to the invention in which a watch movement has been placed; Figure 2 is a graph which schematically illustrates the principle of the method of the invention; Figure 3 schematically illustrates aspects related to the use of a fixed laser; And Figure 4 schematically illustrates certain aspects related to the use of a scannable laser.

Embodiments of the Invention

Figure 1 schematically illustrates a system 1 suitable for carrying out the method of the invention.

[0032] The system 1 comprises a support 3, such as a template, adapted to receive a clock movement 5. The latter can be placed on the support 3 either manually or automatically by a manipulator or a loading device ad hoc. Even if the movement 5 is mounted flat in Figure 1, it is also possible to mount it in a vertical position or in any inclined position.

[0033] The clock movement comprises a frame 7 consisting of a plate and bridges (not shown). This frame 7 carries a driving source 9 such as a mainspring housed in a barrel, which is in kinematic connection with a regulating member 11 of the balance 11a - hairspring 11b type. The kinematic link 12 between the power source and the regulating member 11 typically comprises a going train driving an escapement of any type and is illustrated schematically by an arrow. Other forms of kinematic links are also possible. The balance may have any known shape, and may or may not include, on one or more surfaces of its rim (in particular on its outer side wall), one or more layers of material denser than the rest of the balance, such as gold, in order to maximize the influence of the serge on the inertia of the balance 11a. The effective length of spiral spring 11b can be either predetermined and non-adjustable, or changeable through a racket or the like.

The regulating member 11 is preset to present a delay, that is to say a frequency that is too low compared to the desired value. Thus, a removal of material from the balance 11a, by reducing its inertia, will lead to an increase in the frequency of oscillation of the regulating member 11, in order to improve its adjustment and thus reach a value which is within an acceptable range according to the applied standard. A delay of between 0 and 300 s/d is typical for this purpose. If, in an industrial way, we prefer to have to correct only slightly to maintain an efficient process, we can nevertheless consider making corrections of several hundred seconds per day. The rate of the movement is determined by a suitable system (acoustic, optical, magnetic, etc.) in a conventional manner, so that its delay is known. On the basis of this known delay, the patterns to be ablated in one or more steps on the surface of the balance wheel 11a can be predetermined in order to correct the course of the oscillator 11. This predetermination can be done by modeling, or by choosing from among standardized patterns according to the delay of the oscillator 11. By "pattern" is meant the positions, shapes, lengths, widths and depths of the removal of material to be carried out.

The system further comprises a measuring device 13, arranged to measure the angular displacement of the balance 11a when it oscillates. This measuring device 13 is in communication with a controller 15, adapted to control an ablation laser 17 arranged to direct its beam towards the balance 11a in order to selectively remove material from the latter. Typically, the laser 17 is arranged to ablate the material on the outer wall of the rim of the balance wheel 11a, but can alternatively ablate one of its faces on the back side or on the dial side, or any other part of the surface of the balance. pendulum.

It is also possible to provide a suction system (not shown) to suck up any residues of material ablated by the laser 17 so that they do not contaminate the movement 5 or the support 3.

[0037] The measuring device 13 can be of any suitable type, in particular a high-speed digital camera, a laser sensor (point, line or other, or a Doppler effect sensor making it possible to measure the speed of the balance rim 11a), a point or linear chromatic confocal sensor, an interferometric sensor, an acoustic sensor, a magnetic sensor or any other sensor capable of performing measurements having a temporal resolution as well as an adequate precision. Preferably, the temporal resolution of the sensor is 500 µs (2 kHz) or better, preferably 300 µs (3.33 kHz) or better, more preferably 100 µs (10 kHz) or better, and this independently of the type of sensor or high-speed digital camera. In each case, the measuring device 13 and/or the controller 15 is adapted to be able to process the signals generated by the measuring device in order to determine the angular position of the pendulum 11a each time a measurement is taken. In order to facilitate the measurement, the balance 11a can be provided with one or more markings or the like in order to facilitate taking these measurements and to increase their precision, but the shape of the balance (arms, weights, bad roundness, etc. ) or its surface texture may also suffice, depending on the kind of measurement being made.

The measuring device 13 can also be adapted to directly measure the direction of rotation of the pendulum 11a, which is of course already the case when it is a high-speed digital camera. In the case of a point optical sensor, it is possible, for example, to provide two measuring points angularly offset with respect to the axis of rotation of the pendulum 11a, in order to provide two signals offset in time during the passage of an arm ( or similar structure) in front of the measuring device 13. The positive or negative phase shift of the two signals picked up at the two measuring points thus allows a direct determination of the direction of rotation of the pendulum 11a during each passage of the arm (or similar) in front of the device measurement 13. The accuracy of tracking the movements of the balance 11a over time can thus be maximized, even by using simple optical sensors.

In the arrangement shown, the measuring device 13 is optical and is arranged to observe the upper side (according to the orientation of the figure) of the balance 11a, but can also observe its outer side wall.

[0040] The laser 17, which can for example be of the picosecond or pulsed femtosecond type, is typically directed towards the outer side wall of the balance 11a, but can alternatively act on an exposed face (upper side according to the orientation of FIG. 1 ) of the last. The laser 17 can be fixed relative to the support 3 or alternatively can be provided with a scanner system comprising one or more mirrors, lenses, diffractive elements or the like which are movable and controllable, in order to be able to scan the laser beam at the surface of the pendulum it intersects. Of course, the power of the laser as well as the diameter of its beam must be adapted to the desired goal. The pulse frequency of the laser 17 can be for example between 200 Hz and 100 kHz.

[0041] The heart of the invention relates to the way in which the laser 17 is controlled by the controller 15 on the basis of the measurements taken by the measuring device 13.

[0042] First, a movement 1 is wound up in order to ensure a maximum oscillation amplitude greater than 180° (to be able to fire with the laser 17 over 360° of the periphery of the balance wheel over two successive alternations), or even at bottom in order to obtain a maximum amplitude, and is mounted on the support 3 either manually or by a robot or other movement manipulation device. The maximum amplitude ensures that the entire periphery of the rim of the balance wheel 11a passes in front of the laser 17. The rate delay of the movement 1 is measured either before or after the mounting of the latter on the support 3, by means known (optical, acoustic, magnetic or similar).

[0043] The main measurement and ablation methodology is illustrated in FIG. 2, which shows the oscillation of the pendulum 11a via a sinusoidal curve representing its angular position with reference to its rest position.

As this figure clearly shows, during at least part of a first half-wave 100a, a plurality of measurements (indicated by circles) of the position and/or the angular speed of the balance wheel 11a are performed by the measuring device 13, typically at regular intervals. As illustrated by FIG. 2, this first half-alternation 100a is the first rising half of an alternation, extending from the neutral position of the regulating member 11 towards one of its overturning positions, i.e. i.e. one of its positions in which it stops momentarily before falling back to its neutral position. These measurements are compared with a mathematical model of the dynamic behavior of the regulating member 11 in order to determine its oscillation frequency, its phase, as well as, at least for certain alternations, its amplitude. The latter can, of course, be determined for the rising half-cycle of each cycle or of certain predetermined cycles, if desired.

The mathematical model can be analytical (a priori) or empirical (a posteriori). For example, the displacements of the balance wheel 11a can be modeled as a simple sinusoid of the kind sin (θ) or can also incorporate terms and parameters representing the damping linked to the tribology of the balance wheel pivot and can also incorporate terms representing disturbances linked to the interaction with the escapement and the impulse received from the anchor. Alternatively, an empirical model can be generated by studying the oscillation of a large number of regulating members 11 in order to obtain a model a posteriori for the type of movement 5 and regulating member 11 in question.

[0046] It is also possible to perform measurements on a plurality of complete oscillations in order to refine the parameters of the model before performing the ablation and thus to improve its prediction accuracy with respect to the regulating organ. being settled.

[0047] The quantity of material to be ablated from the rim of the balance wheel 11, as well as the positions of the zone or zones to be ablated (together defining an ablation pattern), have therefore been determined beforehand on the basis of the delay of the oscillator 11, in order to correct the rate of movement 5 and to bring it towards a rate which is closer to 0 s/d. The laser is commanded by controller 15 to fire at set times (as indicated by the squares in Figure 2) during the next half cycle 100b, directly following the first half cycle 100a. These moments are determined according to the position of the pendulum predicted on the basis of the measurements and the mathematical model. Thus, the ablation will take place at the right times and on the desired area(s) and according to the desired shapes and depths. Indeed, no additional measurement is carried out during the second half-cycle 100b, the moments for the ablation being determined exclusively on the basis of the aforementioned predictions.

The fact of performing measurements on a first rising half-wave and cutting during the next falling half-wave maximizes the accuracy of the predictions of the angular position of the balance 11a over time. In fact, the shocks associated with the operation of the escapement (stoppage, impulse, etc.) can cause the behavior of the balance wheel to vary significantly. Similarly, the amplitude of the balance wheel in certain movements is not stable from one alternation to another. Since the pendulum 11a is not disturbed by the escapement between the measurements and the firings of the laser, the rotary behavior of the pendulum 11a during this period can be determined very precisely. The shots of the laser 17 thus ablating the desired area(s) with great precision.

The process can be repeated over several alternations in both directions of rotation, in order to adjust the operation of the regulating member precisely and very quickly. At the same time, any measured imbalance can be corrected by ablating material asymmetrically.

As mentioned above, the laser beam can be fixed and thus always directed in the same direction, or can be controllable, for example via one or more mirrors, lenses, diffractive or similar elements, mobile in rotation and/or actuated by actuators in order to be able to scan the laser beam on the surface of the balance wheel 11a, along one or more axes. Furthermore, the energy of each pulse of the laser 17 and/or its focus can be dynamically modulated.

Figure 3 schematically illustrates methods for using a laser 17 with a fixed beam 17a, which represents the simplest solution. In the arrangement illustrated, the beam 17a intersects the pendulum on the outer side wall of the rim, substantially perpendicular to the latter. According to the oscillations of the pendulum, the beam 17a, which is fixed relative to the support 3, can ablate one or more substantially linear zones along said wall.

[0052] If the pulse energy, the firing rate and the size of the laser spot are fixed on the rim of the balance 11a (which is not compulsory, one or more of these parameters being able to alternately vary ), the amount of material ablated depends on the longitudinal overlap of the successive laser pulses on the rim, which depends on the speed of the rim. The latter varies during the oscillation, and therefore the amount of ablated material per unit length on the serge is not constant, as illustrated next to the indication „Synchro OFF“. This does not imply that such a way of controlling the firing of the laser is not possible, nor usable, but it is not optimal and may involve difficulties which are however not prohibitive, depending on the qualitative requirements aimed at.

[0053] From the information given by the controller 15 on the basis of the measurements taken by the measuring device 13, the firing rate fLdu laser 17 can be adapted to the angular speed of rotation of the pendulum in order to guarantee uniform coverage of the constant laser pulses, performing laser shots on equidistant points. This principle is illustrated next to the indication „Synchro ON“. Indeed, the measurements taken during the rising half-cycle make it possible to predict the speed of the rim of the balance 11a so that the laser fires on the predefined places. The firing rate of the laser 17 can thus be adapted to the speed of rotation of the pendulum, in order to distribute the firings of the laser, as mentioned above, according to the desired pattern.

[0054] In doing so, by constantly and proportionally adapting the rate of fire to the speed of the serge, either continuously or by angular sector of x° (where x is, for example, chosen between 5° and 20° of rotation), the overlapping of the laser pulses can be substantially uniform on the surface of the pendulum 11a. Therefore, the amount of ablated material per unit length around the edge of the serge can also be substantially constant.

[0055] A continuous adaptation of the rate of fire applies to any place on the rim, but is in particular the most relevant method when the removal of material is carried out close to the cusps of the pendulum. 11a. In the vicinity of these points, the variation of the instantaneous speed as a function of time, that is to say the acceleration of the rim, is maximum.

[0056] If the removal of material takes place when the serge is close to its maximum speed, that is to say when the pendulum is traversing an angle of +/- 45° with respect to its position neutral, an adaptation of the firing rate of the laser 17 by annular sector is relatively simple to implement. In such a case, the displacement of the serge is divided into sectors of, for example, 5°, 10°, 15°, 20° (or any other angle) of rotation and a respective rate of fire is applied for each section. Since the angular velocity of the rim remains substantially constant in each section, a suitable rate of fire in each of the latter ensures that the removal of material takes place in a substantially constant manner per unit length of the circumference. The same considerations apply, mutatis mutandis, when the laser 17 is arranged such that its beam 17a is arranged to ablate material on the upper or lower surface of the balance 11a.

Figure 4 schematically illustrates the situation when the laser 17 is arranged such that its beam 17 intersects the outer wall of the rim, and is adapted so that its beam 17a can scan the plane of the balance 11a. When such a laser scanner is used and, if in addition, the energy of the pulses, the firing rate fLet the size of the laser spot is fixed, the quantity of material ablated from the serge depends on the longitudinal overlap of the successive laser pulses on Serge. The latter depends on the speed of the serge as well as the scanning speed of the laser beam.

[0058] On the basis of the measurements of the movement of the pendulum 11a during the first half-cycle, the speed of the serge when said predetermined zone or zones will be ablated during the second half-cycle is predicted. Thereafter the scanning speed vscandu laser on the rim is continuously adapted so as to obtain a regularity of longitudinal overlap of the successive laser pulses on the periphery of the rim. At the same time the focus of the laser 17 can be adapted so that the size of its spot is optimal for effecting the desired ablation.

The scanning speed of the laser beam 17a can either be adapted continuously, or by angular sector of x°, by analogy to the adaptation of the firing rate for the fixed laser as described above, the same slew rate considerations, mutatis mutandis.

The same considerations concerning the scanning of the beam apply, mutatis mutandis, when the laser 17 is arranged to ablate material on one of the faces of the rocker 11a other than the outer wall of the rim. In such a case, the beam 17 can be moved to follow the rotation of the pendulum 11a in order to ablate zones according to a desired pattern.

[0061] It is also possible to move the laser beam 17a relative to the pendulum 11a in a direction perpendicular to those mentioned above, in order to ablate areas in the form of a band which is wider than the laser spot. , and/or to ablate according to other more complex patterns. This also applies to the case where the beam 17 cannot be scanned to follow the rotation of the pendulum. Furthermore, the energy and/or focus of the laser can be dynamically modulated in order to increase the possibilities at the level of the ablation patterns.

[0062] The mathematical calculations necessary to perform the measurements as well as the determination of the areas to be ablated, the predictions of the angular position as well as the speed of the pendulum and the control of the laser (firing rate, scanning speed, etc.) are to be carried out. the scope of those skilled in the art and therefore do not require any detailed description here. Indeed, the scientific literature reveals a large number of ways of implementing this aspect of the invention, which is in no way limited to a particular calculation method.

[0063] After the ablation step, the result of the laser shots (that is to say the location and possibly also the depth of the ablated patterns) can optionally be checked by means of any sensor arranged to be able to measure the surface of the balance 11a which has been ablated. This sensor can be, for example, a high-speed digital camera, or a chromatic confocal sensor, and can be done in dynamic mode when the pendulum 11a oscillates, or in static mode. In the latter case, an ad hoc mechanical means can be used to control the angular position of the balance relative to the sensor.

This control can be performed by the measuring device 13 itself if the latter comprises a sensor of the desired type and is arranged to perform its measurements on the same surface as that ablated by the laser 17. Alternatively, an additional sensor among those proposed, can be expected.

The measurements of the ablated surface thus taken make it possible to check that said predetermined zone or zones have been ablated correctly, and that the right quantity of material has been removed. A chromatic confocal sensor is particularly advantageous for this purpose, since it makes it possible to directly measure the depth of the ablation.

[0066] Although the invention has been previously described in connection with specific embodiments, other additional variants are also possible without departing from the scope of the invention as defined by the claims.

Claims (18)

1. Method for adjusting the oscillation frequency of an oscillator (11) balance (11a) - hairspring (11b) of a clockwork movement (5), said movement (5) being mounted on a support (3 ) and having a known rate delay, said balance wheel being intended to be modified by removal of material from said balance wheel (11a) in at least one predetermined zone, the method comprising the following steps, carried out with the oscillator in a state of oscillation: a) taking measurements of the angular position of said balance wheel (11a) over at least a first half-wave; b) comparing said measurements with a mathematical model in order to determine the frequency, phase and amplitude of said pendulum (11a); c) on the basis of said mathematical model and of said measurements, modeling the angular displacement of said balance wheel (11a) during a second half-wave which directly follows said first half-wave; d) on the basis of the modeling of step c), controlling a laser (17) to ablate, during said second half-wave, material from said rocker arm (11a) in said at least one predetermined zone. 2. Method according to the preceding claim, wherein said first half-wave is a rising half-wave. 3. Method according to one of the preceding claims, wherein, during steps a) and b), the amplitude of said balance wheel (11a) is determined at least during certain alternations. 4. Method according to one of the preceding claims, wherein the beam of said laser (17) is fixed relative to the support (3). 5. Method according to the preceding claim, in which the firing rate of said laser (17) is adapted to the angular speed of the pendulum (11a) when firing said laser (17), on the basis of said modeling of step c ). 6. Method according to the preceding claim, wherein said firing rate of said laser (17) is continuously adapted. 7. Method according to claim 5, in which said firing rate of said laser (17) is determined for each of a plurality of predetermined angular sectors of the pendulum. 8. Method according to one of claims 1 to 3, wherein said laser (17) is arranged such that its beam (17a) is scannable. 9. Method according to the preceding claim, in which the scanning speed of said laser beam (17a) is adapted to the angular speed of said pendulum (11a) when firing said laser (17), on the basis of said modeling of step vs). 10. Method according to the preceding claim, in which said scanning speed is continuously adapted. 11. Method according to claim 9, in which said sweeping speed is determined for each of a plurality of predetermined angular sectors of said pendulum (11a). 12. Method according to one of the preceding claims, wherein said laser beam (17a) is directed towards an outer wall of the balance. 13. Method according to one of the preceding claims, in which step a) is carried out by means of a measuring device (13) which comprises at least one of: • a high-speed digital camera, • a laser sensor, • a Doppler effect laser sensor, • a chromatic confocal sensor, • an interferometric sensor, • an acoustic sensor, • a magnetic sensor. 14. Method according to one of the preceding claims, further comprising, after step d), a step of checking said at least one ablated zone by means of a confocal chromatic sensor and/or a camera at high speed. 15. System (1) for adjusting the frequency of a regulating member (11) of a watch movement (5), comprising: – a support (3) suitable for receiving a watch movement (5) comprising a balance (11a) - hairspring (11b) regulating member; – an ablation laser (17) adapted to direct its laser beam (17a) towards said pendulum (11a) when a movement (5) is mounted on said support (3); – a measuring device (13) suitable for measuring the displacements of said balance wheel (11a) when a movement (5) is mounted on the support; – a controller (15) adapted to receive signals from said measuring device (13) and to control the firing of said laser (17) in order to ablate material from said pendulum (11a) in at least one predetermined zone, according to the method of one of claims 1 to 14. 16. System (1) according to the preceding claim, wherein said measuring device (13) comprises at least one of: • a high-speed digital camera, • a laser sensor, • a Doppler effect laser sensor, • a chromatic confocal sensor, • an interferometric sensor, • an acoustic sensor, • a magnetic sensor. 17. System (1) according to one of claims 15 and 16, wherein said laser (17) is arranged to direct its beam (17a) in a radial direction relative to said beam (11a). 18. System (1) according to one of claims 15 to 17, further comprising a chromatic confocal sensor and/or a high-speed digital camera arranged to perform measurements of said at least one predetermined zone.