Method for generating a control signal for a conveyor, method for controlling the conveyor, and corresponding conveyor

Abstract

Method for generating a conveyor control signal, method for controlling the conveyor, and corresponding conveyor. The invention relates to a method for generating a conveyor control signal with at least one forward step (E1), one reverse step (E2), and one direction change step (E'). The control signal includes trajectory portions corresponding to acceleration phases (A1, A2) and secondary phases known as jerk phases (j). The generation method includes steps for establishing initial parameters, calculating the period (tmin) from at least one initial parameter, and calculating at least one trajectory portion according to an associated trajectory portion equation. The invention also relates to a method for controlling a conveyor according to a generated control signal, and a conveyor intended to be controlled. Figure for the abstract: Fig. 3a

Description

Title of the invention: Method for generating a control signal for a conveyor, method for controlling a conveyor, and corresponding conveyor

[0001] The present invention relates to the field of conveyors, particularly inertia conveyors, for moving objects or parts of varying sizes and masses towards a collection point, for example. Such conveyors can, for instance, be used in object individualization machines with vision control, enabling automated sorting. The present invention relates in particular to a method for generating a control signal and a method for controlling such a conveyor.

[0002] In many industries, such as the mechanical industry, particularly watchmaking, electronics, and food processing, or in construction (building and public works), objects or materials of varying sizes are produced in large quantities. They must then be packaged into batches, for example, to be sent to distribution centers or to locations where they are used in the manufacture or production of more complex parts or components. Upon leaving the production unit, these parts are generally moved to another station to allow for further processing. One example is the conveying of granular materials or powders (for example, in the food processing or construction industries). The precision of the conveying process allows for accurate dosing of these powders by weight measurement.

[0003] Depending on the type of part to be transported, and more particularly depending on their shape or their constituent material, certain transport devices such as belt conveyors or vibrating rail conveyors cannot be used.

[0004] Indeed, in the case of belt conveyors, the positioning of parts during their transport is not very precise, which can be detrimental to their conformity control, for example by a vision device placed on such a belt conveyor.

[0005] Furthermore, in the case of vibrating conveyors, for example those with blades and electromagnets, the positioning of the parts during transport is also imprecise, and these parts can be damaged during transport due to the vibrations and impacts they experience against each other or against the conveyor surface. Indeed, the parts are not in continuous contact with the conveyor surface and jump and detach from it. Thus, such conveyors are unsuitable for transporting fragile parts, for example. In order to improve productivity, it is necessary to develop conveyors that allow for the transport of fragile or non-fragile parts and that guarantee precise positioning of the parts during their transport.

[0006] Inertia conveyors are known, having a transporting element on which the parts to be transported are placed and move in translation parallel to a horizontal direction. The transporting element has reciprocating movements, such as a back-and-forth motion, to allow the parts to slide on it. Thus, the parts remain in constant contact with the transporting element during their movement, with good accuracy regarding the direction of travel. Such inertia conveyors are therefore suitable for transporting numerous parts, including fragile parts, such as glass parts.

[0007] It is known in particular from conveyors comprising a mechanical drive cam whose rotation makes it possible to generate the reciprocating, back-and-forth movement of the conveying member when it cooperates with such a cam.

[0008] However, such a solution presents reproducibility problems. It has been observed that, particularly for small parts, the conveyor may not function correctly, or the conveying speed may be too slow. Furthermore, parasitic vibrations have been measured in all directions during operation.

[0009] It was also observed with this solution that the gap between certain parts, even if externally identical, could not be constant; the parts could move closer together or, on the contrary, move further apart from each other over time.

[0010] Furthermore, with this mechanical solution, the trajectory of the drive cam is entirely determined by the machining parameters and cannot be adjusted or reconfigured once the conveyor is installed. Moreover, designing a rotary conveyor based on a mechanical cam system can be very complex.

[0011] Another solution has been proposed in which an actuator of the conveying element is controlled by a square wave electrical signal and accelerates discontinuously. However, the discontinuities generate parasitic vibrations, particularly during acceleration transitions, affecting the conveyor's performance.

[0012] The invention aims to overcome, at least partially, one or more of the drawbacks of the prior art by providing a controlled / piloted conveyor that advances parts in a highly repeatable and stable manner, while limiting unwanted vibrations. Another objective is to optimize the speed of the parts transported by the conveyor.

[0013] To this end, the invention relates to a method for generating a control signal for a parts transport conveyor, - said conveyor comprising: a transporting element having a transport surface on which the parts to be transported are intended to be placed, and a drive device configured to drive the transporting element according to an asymmetrical reciprocating motion, the asymmetrical reciprocating motion having a displacement in a direction of advance and a displacement in a direction of recoil opposite to the direction of advance, - said method being configured to generate a control signal of at least one advancement step of the drive device at an advancement speed, of at least one recoil step of the drive device at a recoil speed, and of at least one change of direction step between the advancement step and the recoil step, during the change of direction step, the advancement or recoil speed of the drive device varies until it reaches a zero reversal speed at which the direction of advancement or recoil of the drive device changes.

[0014] According to the invention, the control signal comprises a predefined number of trajectory segments corresponding to at least two acceleration phases with respective non-zero and constant acceleration values ​​over an associated period, and at least one secondary phase, referred to as a jerk phase, with a non-zero period between two acceleration phases. The jerk value is the derivative of the acceleration with respect to time and is constant for all secondary phases. At least one change of direction step is initiated during at least one secondary phase, and the change of direction of forward or backward movement occurs during an acceleration phase, the acceleration being non-zero and constant. The method for generating the control signal comprises: - at least one step to establish a predefined number of initial parameters from among at least one acceleration, at least one time datum, at least one velocity, and one jerk value, - at least one calculation step of at least one period from at least one of the initial parameters, and - at least one calculation step of at least one portion of the trajectory of the drive device according to an associated portion of trajectory equation for a time interval among the period of at least one acceleration phase and the period of at least one secondary phase, the portion of trajectory equation being a function of time, the forward speed, and at least one parameter among: at least one initial parameter including at least one acceleration, the jerk value, at least one period of an acceleration phase, at least one period between two acceleration phases.

[0015] Said generation process may further comprise one or more of the following features described below, taken separately or in combination.

[0016] The control signal defines for example a first acceleration phase with a first constant positive acceleration over a first period.

[0017] The control signal defines for example a second acceleration phase with a second constant negative acceleration over a second period.

[0018] The control signal defines for example a third acceleration phase with a third constant positive acceleration over a third period.

[0019] The initial parameters may include at least one of the accelerations, or even all of them, among the first positive acceleration, the second negative acceleration, the third positive acceleration.

[0020] At least one portion of the trajectory may correspond to a time interval among the first period, the second period, the third period and the period of at least one secondary phase.

[0021] The second negative acceleration may have an absolute value which is maximum compared to the acceleration values ​​reached between two steps of change of direction.

[0022] The third positive acceleration may have an absolute value which is maximum with respect to the acceleration values ​​reached between two steps of change of direction.

[0023] The first period can be an initial parameter.

[0024] The initial speed of the drive device can be an initial parameter.

[0025] During the advancement stage, the drive device may have a positive initial velocity which increases according to the first positive acceleration and which reaches a maximum velocity.

[0026] When the maximum speed is reached, a first reversing stage can begin with a decrease in the speed of the drive device and an acceleration that decreases until reaching the second negative acceleration. The reversing stage can then begin.

[0027] During the recoil stage, the speed of the drive device can decrease according to the second negative acceleration and reach a minimum speed.

[0028] When the minimum speed is reached, a second reversal stage can begin with an increase in the speed of the drive device and an acceleration that grows until reaching the third positive acceleration. A new forward movement stage can then begin.

[0029] At least one period of a secondary phase between two acceleration phases can be calculated from at least two accelerations and the jerk value.

[0030] Said generation method may include a step of calculating the period of the secondary phase between the aforementioned first and second acceleration phases according to the following formula , with abase corresponding to the first acceleration positive, -amin corresponding to the second negative acceleration, and j corresponding to the value of the jolt.

[0031] Said generation method may include a step of calculating the period of the secondary phase between said second and third acceleration phases according to the following formula: , with amax corresponding to the third acceleration positive, -amin corresponding to the second negative acceleration, and j corresponding to the value of the jolt.

[0032] Said generation method may include a step of calculating the period of the secondary phase between the aforementioned third and first acceleration phases according to the following formula , with amax corresponding to the third acceleration positive, abase corresponding to the first positive acceleration, and j corresponding to the shock value.

[0033] At least the second period can be calculated from at least two of the accelerations, the jerk value, the first period, the initial speed of the drive device and the periods of the secondary phases.

[0034] At least the third period can be calculated from at least two of the accelerations, the jerk value, the first period, the initial speed of the drive device and the periods of the secondary phases.

[0035] The third period can be a function of the second period.

[0036] The second period can be greater than or equal to zero.

[0037] The third period may be greater than or equal to zero.

[0038] The third period is for example shorter than the second period.

[0039] Said generation method may include a step of calculating the second period according to the following formula: B ^bP-aac^), with: ^min — 2.4 " 2.4 - A corresponding to a first coefficient that is a function of the acceleration during the said second and third acceleration phases, - B corresponding to a second coefficient that is a function of the acceleration during said acceleration phases, the first period, the initial speed of the drive device, and the period of the secondary phases between the first and second acceleration phases and between the second and third acceleration phases, and - Cpr corresponding to a third coefficient that is a function of the acceleration during said acceleration phases, and of the initial velocity of the device training, the first period, the periods of the secondary phases, and the value of the jolt during the secondary phases.

[0040] Said generation method may include a step of calculating the third period according to the following formula: f —t _l .¾¾. / , with -amin corresponding to the • max — ^ T amax1 min second negative acceleration, amax corresponding to the third positive acceleration, tmin corresponding to the second period, and T corresponding to a fourth coefficient function of the acceleration during said acceleration phases, of the first period and of the periods of the secondary phases.

[0041] Said generation method may include a step of calculating the first coefficient according to the following formula: [ । + ), with -amin corresponding to the second negative acceleration, and amax corresponding to the third phase positive acceleration.

[0042] Said generation process may include a step of calculating the second coefficient according to the following formula: fi — V 1 + amax ) \ ^low^base ^base^x ' J 2 ^0 " am«x J 2 - with abase corresponding to the first positive acceleration, -amin corresponding to the second negative acceleration, amax corresponding to the third positive acceleration, tbase corresponding to the first period, Ti corresponding to the period of the secondary phase between said first and second acceleration phases, r2 corresponding to the period of the secondary phase between said second and third acceleration phases, v0 corresponding to the initial speed of the drive device, and j corresponding to the value of the jolt.

[0043] Said generation process may include a step of calculating the third coefficient according to the following formula: ( Fy F 5 \ y2 ^Jbnse + ^base^l ' J~ + V0 ' ^minr2 + JT + «^3 J + anmx~ ' - with abase corresponding to the first positive acceleration, -amin corresponding to the second negative acceleration, amax corresponding to the third positive acceleration, tbase corresponding to the first period, Ti corresponding to the period of the secondary phase between said first and second acceleration phases, r2 corresponding to the period of the secondary phase between said second and third acceleration phases, r3 corresponding to the period of the secondary phase between said third and first acceleration phases, v0 corresponding to the initial velocity of the drive device, j corresponding to the value of the jolt, C corresponding to a fifth coefficient depending on the acceleration during said acceleration phases, the first period and the periods of the secondary phases, the initial speed of the drive device and the value of the jolt, and T corresponding to the fourth coefficient.

[0044] Said generation process may include a step of calculating the fourth coefficient according to the following formula: •* ^max - with abase corresponding to the first positive acceleration, -amin corresponding to the second negative acceleration, amax corresponding to the third positive acceleration, tbase corresponding to the first period, Ti corresponding to the period of the secondary phase between said first and second acceleration phases, r2 corresponding to the period of the secondary phase between said second and third acceleration phases, r3 corresponding to the period of the secondary phase between said third and first acceleration phases.

[0045] Said generation process may include a step of calculating the fifth coefficient according to the following formula: C- <haJcT +tbaseTï + i: + tbaseT2 + T(r2 + tbaseT3 + T\T3} ' / r? \ r' T2 ri r2 ri t* a min a max~ ~J~6~J~ r 2 + JT ' J~ T 3 + j~" r 3~J'6 + +r+r2 + T3), - with abase corresponding to the first positive acceleration, -amin corresponding to the second negative acceleration, amax corresponding to the third positive acceleration, tbase corresponding to the first period, Ti corresponding to the period of the secondary phase between said first and second acceleration phases, r2 corresponding to the period of the secondary phase between said second and third acceleration phases, r3 corresponding to the period of the secondary phase between said third and first acceleration phases, v0 corresponding to the initial speed of the drive device, j corresponding to the value of the jolt.

[0046] According to one embodiment, six trajectory portions respectively associated with the first period, the second period, the third period and the period of each secondary phase between two acceleration phases, are calculated according to six equations of respective trajectory portions.

[0047] Said generation method may include at least one step of calculating a first portion of the trajectory of the drive device, corresponding to the first acceleration phase of the first period, according to a first associated trajectory portion equation: (1): x (0 < t< t base ) = v base t + a bas f- / 2, - with vbase the advance speed of the drive device during the advancement stage, abase the first positive acceleration, tbase the first period, t, the time.

[0048] Said generation method may include at least one step of calculating a second portion of the trajectory of the drive device, corresponding to the secondary phase between said first and second acceleration phases of period rb according to a second associated trajectory portion equation: (2): x(Tl<7 <T2) = x(Tl) + ^(7-71) + - with Tl a first duration corresponding to the first period, T2 a second duration corresponding to the sum of the first period and the period of the secondary phase between the first acceleration phase and the second acceleration phase, vbase the speed of advancement of the drive device during the advancement stage, abase the first positive acceleration, t the time.

[0049] Said generation method may include at least one step of calculating a third portion of the trajectory of the drive device, corresponding to the second acceleration phase of the second period, according to a third associated trajectory portion equation: (3): x(T2 <f<T3) = x(T2) + v base (t-T2) + (a base T2-jT]t2) (t-T2)-a min (t-T2) 2 / 2 - with T2 the second duration, T3 a third duration corresponding to the sum of the second duration and the second period, vbase the advancement speed of the drive device during the advancement stage, abase the first positive acceleration, -amin the second negative acceleration, tmin the second period, Ti the period between the first acceleration phase and the second acceleration phase, j the value of the jolt, t the time.

[0050] Said generation method may include at least one step of calculating a fourth portion of the trajectory of the drive device, corresponding to the phase secondary between the said second and third acceleration phases of period r2, according to a fourth associated trajectory portion equation: (4): x(T3 <t<T4) = (t-T3) -a^t-TZ)2 / 2 + j(t-T3ÿ / 6 - with T2 the second duration, T3 the third duration, T4 a fourth duration corresponding to the sum of the third duration and the period of the secondary phase between the second acceleration phase and the third acceleration phase, vbase the advancement speed of the drive device during the advancement stage, abase the first positive acceleration, -amin the second negative acceleration, tmin the second period, Ti the period between the first acceleration phase and the second acceleration phase, j the value of the jolt, t the time.

[0051] Said generation method may include at least one step of calculating a fifth portion of the trajectory of the drive device, corresponding to the third acceleration phase of the third period, according to a fifth associated trajectory portion equation: (5): x(7'4 <t<T5) = x(T4) + vbaæ( LT4 ) + ( / 2-amin(+r2 ) + / 2) (J-T4)+at^(t-T4 f / 2 - with T2, the second duration, T4 the fourth duration, T5 a fifth duration corresponding to the sum of the fourth duration and the third period, vbase the advancement speed of the drive device during the advancement stage, abase the first positive acceleration, -amin the second negative acceleration, tmin the second period, amax the third positive acceleration, rja the period between the first acceleration phase and the second acceleration phase, r2 the period between the second acceleration phase and the third acceleration phase, j the value of the jolt, t the time.

[0052] Said generation method may include at least one step of calculating a sixth portion of the trajectory of the drive device, corresponding to the secondary phase between the third acceleration phase and a new first acceleration phase of period r3, according to a sixth associated trajectory portion equation: (6): x(T5 <t <T6) = x(T5) + v bœe (t-T5) + ~ ^min ( ^min ^2 ) J^2 ^ma^max)(t-T5) + a^t-TSŸIÏ-jd-TiŸlb - with T2 the second duration, T5 the fifth duration, T6 a period corresponding to the sum of the periods of the three acceleration phases and the three secondary phases, vbase the advancement speed of the drive device during the advancement stage, abase the first positive acceleration, -amin the second negative acceleration, tmin the second period, amax the third positive acceleration, tmax the third period, Ti the period between the first acceleration phase and the second acceleration phase, r2 the period between the second acceleration phase and the third acceleration phase, j the value of the jolt, t the time.

[0053] The control signal of the drive device may include a fundamental frequency having at least one substantially parabolic or parabolic portion.

[0054] The control signal of the drive device may include a fundamental frequency having at least one substantially cubic or cubic portion.

[0055] According to one embodiment, the fundamental frequency has at least three substantially parabolic portions and three substantially cubic alternating portions.

[0056] The drive device can follow a trajectory defined by a curve, such that the curve has on a cycle a successive advance stage and a successive retreat stage, and has at least three parabolic portions and three alternating cubic portions, the parabolic portions corresponding to a movement with constant acceleration.

[0057] These acceleration phases correspond, for example, to the parabolic portions of the trajectory curve.

[0058] The secondary phases correspond for example to the cubic portions of the trajectory curve.

[0059] Said generation method may include a storage step in which at least one representative parameter of the control signal is stored in a conveyor control unit.

[0060] Said generation method may include a memorization step in which the generated control signal is stored in a conveyor control unit.

[0061] The invention also relates to a method for controlling a parts transport conveyor, said conveyor comprising a transporting element having a surface a transport system on which the parts to be transported are intended to be placed, and a drive device configured to drive the transporting element in an asymmetrical reciprocating motion, the asymmetrical reciprocating motion having a displacement in one direction of advance and a displacement in a direction of recoil opposite to the direction of advance. The control method is configured to control, according to a control signal generated by a control signal generation method as defined above: - at least one advancement stage of the drive device at a given forward speed, - at least one step of the drive device recoiling at a recoil speed, and - at least one change of direction step between the forward step and the reverse step, during the change of direction step, the forward or reverse speed of the drive device varying until reaching a zero reversing speed at which the forward or reverse direction of the drive device changes.

[0062] Said piloting method may further comprise one or more of the following characteristics described below, taken separately or in combination.

[0063] Said piloting method may or may not include one or more steps of the method for generating a control signal as defined above.

[0064] Said control method may include at least one preliminary step to extract the control signal or at least one parameter of the control signal stored in a memory of a conveyor control unit.

[0065] The invention further relates to a parts transport conveyor comprising: - a transporting element having a transport surface on which the parts to be transported are intended to be placed, and - a controlled drive device, configured to drive the transporting member according to an asymmetric reciprocating motion, the asymmetric reciprocating motion having a displacement in one direction of advancement during at least one advancement step and a displacement in a direction of retreat opposite to the direction of advancement during at least one retreatment step, the drive device being configured to be controlled according to a control method as defined above.

[0066] The conveyor, controlled or driven according to the control signal generated by the control signal generation method as defined above, offers the following advantages: compactness, high workpiece feed speed, and low parasitic vibrations. Indeed, it is possible to achieve a acceleration amplitude much greater than with a mechanical cam conveyor, and therefore very high workpiece feed speeds.

[0067] Other advantages and features of the invention will become more apparent upon reading the following description, given by way of illustrative and non-limiting example, and the accompanying drawings, among which:

[0068] [Fig-1] represents an embodiment of a linear conveyor.

[0069] [Fig.2] represents an embodiment of a rotary conveyor.

[0070] [Fig.3a] schematically represents an example of the trajectory curve of the conveyor drive device of [Fig.1] or 2.

[0071] [Fig.3b] schematically represents an example of the curve of the evolution of the speed of the conveyor drive device of [Fig.1] or 2.

[0072] [Fig.3c] schematically represents an example of the acceleration phase curve of the conveyor drive device of [Fig.1] or 2.

[0073] In these figures, identical elements bear the same reference numbers.

[0074] The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Simple features of different embodiments can also be combined or interchanged to provide other embodiments, without departing from the scope of the invention as defined by the claims.

[0075] In the description, certain elements can be indexed, such as first element or second element. In this case, it is simply indexing to differentiate and name similar but not identical elements. This indexing does not imply any priority of one element over another, and such designations can easily be interchanged without departing from the scope of this description. Nor does this indexing imply any chronological order.

[0076] The speed of an element, for example of the drive device, can be positive, zero, or negative. In the case of a negative speed, the direction of movement of the drive device is reversed compared to the direction of movement with a positive speed.

[0077] With reference to figures 1 and 2, the invention is in the field of inertia conveyors 1 for transporting one or more objects, such as granules or powder, or parts 3, or any other object, of varying sizes and masses, for example towards a collection point.

[0078] The parts 3 have a bearing surface intended to be in contact with the inertial conveyor 1. The bearing surface may be flat or substantially flat to ensure the stability of this part 3 on the inertial conveyor 1. The bearing surface can also be reduced to a line or even two points. Parts 3 may, in particular, have a general cylindrical or semi-cylindrical shape, such as vials, a general parallelepiped shape, or more complex shapes in the case of washers, seals, screws, bolts.

[0079] Parts transport conveyor

[0080] In general, the inertia conveyor 1 is configured to transport the parts 3 in a direction of advancement represented by the arrow Fl.

[0081] In the example of [Fig. 1], conveyor 1 is linear. In this case, conveyor 1 allows the parts 3 to be transported in a direction of translation. In other words, the parts 3 can be transported along a linear trajectory.

[0082] Alternatively, in the example of [Fig. 2], the conveyor 1 is rotary. In this case, it allows the parts 3 to be transported in a direction of rotation. The parts 3 can then be transported along a trajectory that is at least partly circular or helical, the radius and pitch of which can be fixed or variable.

[0083] In order to transport the parts 3, the conveyor 1 includes a transporting element 5 such as a platform, and a drive device 7 for this transporting element 5.

[0084] The shape of the conveying element 5, such as a platform, can be adapted according to the type of conveyor 1. In the example of [Fig. 1], the platform defines a parallelepiped shape, while in the example of [Fig. 2], the platform has a disc shape. The direction of travel represented by the arrow Fl is, for example, parallel to the long side of the parallelepiped shape of the platform ([Fig. 1]) or, alternatively, rotating around the center of the disc ([Fig. 2]).

[0085] Regardless of the embodiment of the conveyor 1 in Figures 1 and 2, the conveying element 5 has a transport surface 51 on which the parts 3 to be transported are intended to be placed. By way of non-limiting example, the transport surface 51 may be made of a material having a coefficient of kinetic friction less than 0.20, and preferably between 0.08 and 0.15.

[0086] The drive device 7 allows the transport member 5 to be driven according to an asymmetric reciprocating movement, as represented by the double arrow F2.

[0087] The asymmetrical reciprocating motion can occur in a plane defined by a part 10 of a motor such as a servomotor 9, described hereafter with reference to [Fig. 1], the part 10 being translationally movable. According to one embodiment, the asymmetrical reciprocating motion can occur in a plane perpendicular or substantially perpendicular to a drive shaft 91 of a motor such as a rotary servomotor 9, described hereafter with reference to [Fig. 2]. Alternatively, or in addition, the asymmetrical reciprocating motion can occur in a plane defined by the transport surface 51 when the latter is flat.

[0088] Referring also to [Fig. 3a], this is a reciprocating movement with at least one forward step El and at least one backward step E2. During the forward step El, the transport member 5 is moved in the direction of advancement, corresponding to the direction of arrow Fl (Figures 1 and 2). During the backward step E2, the transport member 5 is moved in a backward direction opposite to the direction of advancement.

[0089] The drive device 7 is configured to be controlled / piloted according to a control signal generated according to a method of generating a control signal described later.

[0090] This is a training device 7 for which at least certain parameters, allowing a trajectory curve to be obtained as a function of time, can be calculated as described below.

[0091] The asymmetrical movement of the drive device 7 can overcome static friction forces between the transport surface 51 and the mounting surface of the parts 3 to be transported, so that the parts 3 slide on the transporting member 5.

[0092] The asymmetrical movement of the drive device 7 follows an acceleration profile detailed later.

[0093] The drive device 7 may be a servo device. It may include, in particular, a motor, specifically a servomotor 9.

[0094] For example, the servomotor 9 comprises a motor and control electronics. The control electronics include at least one drive, more specifically a digital drive (not shown), and a software controller or PLC (not shown). The drive is configured to supply power to and regulate the motor according to the positions received from the software controller or PLC.

[0095] The transport member 5 is fixed to the servomotor 9 and will follow the movements of the latter. This can be a rigid mechanical fixing, for example by screwing.

[0096] According to the first embodiment shown schematically in [Fig. 1], with a linear conveyor 1, the drive device 7 comprises a linearly moving servomotor 9. In this case, the servomotor 9 can move along a translational direction.

[0097] The servomotor 9 includes, in particular, a moving part 10 and a fixed part. According to a specific, non-limiting example, the fixed part may be a magnetic track 11. The magnetic track 11 defines, for example, a channel with two rows of magnets arranged on either side of the moving part 10 of the servomotor 9, parallel to the direction of translation. The servomotor 9, for example the moving part 10, includes windings, more precisely three windings, which generate a magnetic field when electrically energized. The magnets forming the magnetic track 11 can then interact with this magnetic field, so that the moving part 10 of the servomotor 9 can move.

[0098] Alternatively, the magnetic track can form the moving part intended to cooperate with the fixed windings.

[0099] Advantageously, the drive device 7 includes a guide system not shown, such as a system of rail sliders, for holding the servomotor 9.

[0100] According to the second embodiment shown schematically in [Fig.2], with a rotating conveyor 1, the drive device 7 comprises a rotaryly moving servomotor 9.

[0101] In this example, the rotary servomotor 9 comprises a drive shaft 91, and the magnets forming the magnetic track 11 can be carried by this drive shaft 91. The servomotor 9 further comprises windings 93 wound around the drive shaft 91 carrying the magnets. In this case, the windings 93 are fixed, and it is the magnets that are moved. Alternatively, the magnetic track could form the fixed part intended to cooperate with the moving windings in a manner similar to the example described above.

[0102] According to either embodiment, the windings of the servomotor 9 are connected to the drive. The controller or software PLC communicates to the drive the successive positions that the motor must reach over time. For example, a new position is sent every millisecond.

[0103] As an alternative or in addition, it may be envisaged that the drive device 7 includes at least one piezoelectric element.

[0104] Furthermore, the conveyor 1 may include at least one side edge (not shown). It may be fixedly arranged on one side of the conveying member 5. It may be arranged perpendicular to the conveying surface 51.

[0105] According to a particular embodiment not shown, the conveyor 1 may include an image acquisition system for taking at least one image of each individual part 3 moving within a predefined measurement zone. An optical detector may be arranged to detect the arrival of a part 3 in the measurement zone in order to trigger image acquisition. An image processing system may be provided to process the images taken by the image acquisition system in order to determine, for example, whether the parts 3 conform or not, so that parts 3 with a conformity defect can be removed, for example.

[0106] Piloting method

[0107] With reference to Figures 1 to 3c, generally, during the operation of conveyor 1, the parts 3 are placed on the conveying member 5, and the drive device 7, more specifically the motor, is driven to drive the conveying member 5 according to the asymmetrical movement (arrow F2) with a successive advance step El and a retreat step E2.

[0108] To do this, the piloting method can pilot or control the conveyor 1 according to at least one control signal to control the advance, the retreat, the change of direction of the drive device 7.

[0109] The control signal can be generated by a method for generating at least one control signal detailed later. The control signal comprises a predefined number of trajectory portions associated with trajectory portion equations (explicitly detailed later), the trajectory portions corresponding in particular to at least two acceleration phases, for example three acceleration phases Al, A2, A3, and to at least one secondary phase called a jerk phase with a non-zero period ri, r2, t3 between two acceleration phases Al, A2, or A2, A3 or A3, AL. The control signal also comprises the trajectory portion equation(s).

[0110] The steps of such a method for generating a control signal (or several control signals) can be implemented during the control of conveyor 1.

[0111] Alternatively, the steps of the process for generating a control signal (or several control signals) can be implemented in advance, separately from the control process. In the latter case, the control signal, and / or one or more parameters representing the control signal, such as equations, can be stored in a memory of a control unit (not shown) of the conveyor 1. The control process may include a preliminary step for accessing the memory and extracting or reading the control signal or one or more parameters representing the control signal, such as equations.

[0112] The method of piloting the conveyor 1, according to the control signal generated during the piloting process or in advance and extracted for piloting, comprises the following steps.

[0113] Progress stage

[0114] Overall, during the advancement step El, the drive device 7 exhibits a positive and non-zero advancement speed vbase. The advancement speed of the drive device 7 is greater than or equal to the speed of the parts 3.

[0115] More specifically, when the advancement step El is initiated, the drive device 7 has a positive initial velocity v0. The drive device 7 then evolves with the advancement velocity vbase increasing ([Fig. 3b]) according to an initial positive acceleration abase ([Fig. 3c]), notably until reaching a maximum velocity vmax. It should be noted that the advancement velocity vbase of the drive device 7 continues to increase even at the end of the period tbase exhibiting a first positive acceleration abase, as long as the acceleration is positive which occurs approximately in the middle of the period ti (see figures 3b, 3c).

[0116] The drive device 7 advances the transport member 5 relatively "slowly". The drive device 7 accelerates only slightly. This is a first positive acceleration abase which is weak.

[0117] This corresponds to a first acceleration phase Al exhibiting the first positive acceleration abase over a first period tbase. The first acceleration phase Al corresponds to an adhesion phase of part 3 or parts 3 on the conveyor 1. The part or parts 3 grip by friction on the transport surface 51 and are carried along by it so that they advance along the arrow Fl during the advancement step EL

[0118] First step in changing direction between forward and backward

[0119] When the drive device 7 reaches the maximum speed vmax, a first change of direction step E' can begin, before the drive device 7 moves backward.

[0120] During this first change of direction step E', the speed of the drive device 7 decreases according to an acceleration that diminishes until it reaches a second negative acceleration -amin. It should be noted that the variation in acceleration (which decreases or increases depending on the change of direction) is therefore progressive and continuous, which also ensures the continuous nature over time of the control of the drive device.

[0121] When the decreasing speed of the drive device 7 reaches zero reversing speed, the acceleration of the drive device 7 corresponds to this second negative acceleration -amin, which is not zero. The change of direction therefore occurs during the second acceleration phase A2, at a non-zero and constant acceleration -amin. The time interval during which the reversing speed is zero tends towards zero because the acceleration at this moment is not zero. In other words, at the reversing position with a zero reversing speed, there is no stop. The advantage of the absence of a stop is the continuity of movement and the fact that there is no generation of extraneous noise that disrupts the transport of the parts 3 and impairs productivity. The inventors have found that a productivity gain of around 100%, or even up to 300% in some cases, can be achieved compared to conveyors known in the prior art.

[0122] Recoil step

[0123] The reversing step E2 begins when the speed of the drive device 7 reaches the reversing speed which is zero.

[0124] During the recoil step E2, the drive device 7 recoils very rapidly, while the parts 3 lose traction and are carried along in the direction of transport (arrow Fl) by their inertia, thus continuing to move forward along arrow Fl (Figures 1, 2). The speed of the drive device 7 is negative and decreases according to the second negative acceleration -amin (Figures 3b, 3c), and this speed of the drive device 7 reaches a minimum speed vmin.

[0125] The second negative acceleration -amin can, in particular, be sufficiently large to overcome the static friction forces between the transport surface 51 and the mounting surface of the parts 3 to be transported, so that the parts 3 remain in contact with the transporting element 5 and slide on it. This negative acceleration -amin is constant over a second period tmin. This corresponds to a second acceleration phase A2.

[0126] The acceleration of the drive device 7 has, during the second period tmin, an absolute value laminl greater than or equal to the absolute value of the first positive acceleration labasel during the first acceleration phase AL

[0127] The second negative acceleration -amin must have the highest possible absolute value so that the time during which the absolute value of the acceleration is greater than the adhesion threshold of the part with the support is as short as possible.

[0128] This absolute value laminl is maximum, with respect to the acceleration values ​​reached between two change of direction steps E', E”. These include the acceleration values ​​reached between the instant when the speed of the drive device 7 reaches the maximum speed vmax triggering the first change of direction step E' and the instant when the speed of the drive device 7 reaches the minimum speed vmin triggering a second change of direction step E' ', as described below.

[0129] Second stage of change of direction between retreat and advance

[0130] When the drive device 7 reaches the minimum speed (negative speed), a second change of direction step E” can begin, before the drive device 7 moves forward again.

[0131] During this second change of direction step E”, the drive device 7 accelerates again. The speed of the drive device 7 increases according to an acceleration that grows until it reaches a third positive acceleration amax. Here too, a continuous and progressive variation in acceleration is observed so as not to induce noise or disturbances that would impair the efficiency of the drive device 7.

[0132] This third positive acceleration amax is constant over a third period tmax. This corresponds to a third acceleration phase A3.

[0133] When the drive device 7, whose speed is increasing, reaches zero reversing speed, the acceleration of the drive device 7 corresponds to this third positive acceleration amax, which is non-zero. The change of direction therefore occurs during the third acceleration phase A3, at a non-zero and constant acceleration amax. As mentioned previously, the time interval during which the reversing speed is zero tends towards zero because the acceleration at that moment is not zero. In other words, at the reversing position with a reversing speed of zero, there is no stop.

[0134] The acceleration of the drive device 7 has, during the third period tmax, an absolute value lamaxl greater than or equal to the absolute value of the first positive acceleration labasel during the first acceleration phase AL

[0135] This absolute value lamaxl is maximal with respect to the acceleration values ​​reached between two direction change steps. These include the acceleration values ​​reached between the instant when the speed of the drive device 7 reaches the minimum speed triggering the second direction change step and an instant when the speed of the drive device 7 reaches the maximum speed triggering a new first direction change step.

[0136] A new advancement stage El can begin when the speed of the drive device 7 reaches the zero reversing speed.

[0137] Secondary phases

[0138] The secondary phases known as jerk phases allow a link between the different acceleration phases A1, A2, A3, they ensure a continuity of the acceleration profile.

[0139] In particular, according to the embodiment described with reference to Figures 3a to 3c, three acceleration phases A1, A2, A3 and three secondary jerk phases can alternate over a cycle.

[0140] The secondary jerk phases between two acceleration phases A1, A2, A3 have non-zero durations or periods r2, t3. The jerk value j is the derivative of the acceleration with respect to time. This jerk value j is constant for all secondary jerk phases.

[0141] The method for generating at least one control signal is described below.

[0142] Method for generating at least one control signal

[0143] As stated previously, the control signal comprises a predefined number of trajectory portions associated with trajectory portion equations (explained later), the trajectory portions corresponding in particular to at least two acceleration phases, for example three acceleration phases A1, A2, A3, and to less a secondary phase called a jerk of non-zero period r2, between two acceleration phases Al, A2, or A2, A3 or A3, Al.

[0144] The trajectory of the drive device 7 is defined by a trajectory curve CO, an example of which is shown schematically in [Fig.3a].

[0145] The trajectory can be calculated in advance (relative to the piloting method) and with precise characteristics. The motion profile is calculated analytically, as detailed below, in order to obtain the trajectory CO curve.

[0146] The CO curve defines the evolution of positions P (for example in millimeters or centimeters) of the drive device 7 over time t (for example in seconds). In [Fig. 3a], the scales of positions P and time t are given for illustrative purposes only and are not limiting.

[0147] The control signal may include a fundamental frequency having at least one substantially parabolic or parabolic portion or similar to a parabola, corresponding to a first portion Cl of the curve C0.

[0148] Alternatively or in addition, the control signal may include a fundamental frequency having at least one substantially cubic or cubic portion or similar to a cubic curve, corresponding to a second portion C2 of the curve C0.

[0149] According to a particular example, at least three parabolic or substantially parabolic portions and three alternating cubic or substantially cubic portions may be provided.

[0150] The control signal may occasionally deviate from a purely parabolic and / or cubic control.

[0151] Of course, a control signal with higher frequencies, with additional harmonic components of the fifth order and above, is conceivable. This will have no consequences on the movement because the high frequencies will be filtered by the winding in the case of an electric motor, and by mechanical inertia in all cases. It can be noted that any harmonic components of the second, third, or fourth order, if their amplitude is low compared to the fundamental frequency, have little or no impact on the performance of conveyor 1. Similarly, an anharmonic component, i.e., of any frequency, may have no significant effect if its amplitude remains low.

[0152] In particular, with reference to Figures 1 to 3b, one or more control signals are generated for at least one advancement step El of the drive device 7 at an advancement speed vbase (positive speed), for at least one recoil step E2 of the drive device 7 at a recoil speed (negative speed), and for at least one change of direction step E' or E”, between the advancement step El and the recoil step E2.

[0153] The acceleration phases Al, A2, A3 have different acceleration values. Each acceleration phase Al, A2, A3 has a respective acceleration value abase, -amin, amax which is constant over an associated period tbase, tmin, tmax.

[0154] The first portions Cl of the CO curve correspond to the acceleration phases A1, A2, A3, and therefore to a motion with constant acceleration. The second portions C2 of the CO curve correspond to the secondary phases known as jerk phases.

[0155] The secondary jerk phases allow the CO curve to be smoothed ([Fig.3a]). The trajectory, defined by this CO curve, is obtained by integrating twice the acceleration and jerk values ​​j, examples of which are given below.

[0156] Figure 3b shows a curve of the evolution of the speed V (for example in millimeters per second) of the drive device 7 over time t (for example in seconds). In Figure 3b, the speed V and time t scales are given for illustrative purposes only and are not limiting.

[0157] During the direction change step E' or E”, the forward or reverse speed of the drive device 7 varies, passing through a zero reversing speed at which the direction of forward or reverse movement of the drive device 7 changes. When the zero reversing speed is reached, the drive device 7 exhibits a non-zero and constant acceleration -amin, amax over a predefined period tmin, tmax. This acceleration -amin, amax has a maximum absolute value over the predefined period tmin, tmax, compared to the acceleration values ​​reached between two direction change steps E' and E”.

[0158] Figure 3c shows a curve of the evolution of the acceleration a (for example in units of acceleration g) of the drive device 7 over time t (for example in seconds). In Figure 3c, the scales of acceleration a and time t are given for illustrative purposes only and are not limiting.

[0159] The definition of the trajectory (C0 curve of [Fig.3a]) can be obtained from the acceleration curve ([Fig.3c]).

[0160] It must be understood that when the drive device 7 has a speed, an acceleration is applied to reverse the speed and also the direction of movement of the drive device 7.

[0161] In the case of a positive velocity, the applied acceleration will first decrease the speed of movement until it passes through zero (reversal velocity), and it is at this moment that the direction of movement changes. At this moment, the acceleration is non-zero (here negative).

[0162] In the case of a negative velocity, the applied acceleration will first increase the speed of movement to pass through zero (reversal velocity), and it is at this moment that the direction of movement changes. At this moment, the acceleration is non-zero (here positive).

[0163] Examples of equations of portions of the trajectory

[0164] The method of generating the control signal comprises one or more steps to calculate the trajectory of the drive device 7 corresponding to the CO curve of [Fig.3a].

[0165] The trajectory of the drive device 7 is periodic with period T6. The equation of the trajectory x(t) of the drive device 7 over time t can be defined in parts over the period T6. The period T6 corresponds to a cycle comprising the first A1, second A2, third A3 acceleration phases, and the secondary alternating jerk (or jerk) phases, i.e., T6 = 1 / T + 7 / T + 7 - 2 / T + 0.0 + 73.

[0166] The trajectory of the drive device 7 over time t can be defined as a recurrence of the trajectory equation over the period T6. In other words, the trajectory equation can be calculated over this period T6 and then looped, the point at time zero t = 0 corresponding to the point at time t = T6.

[0167] Alternatively, at the end of period T6, instead of looping on the same trajectory, another trajectory can be calculated from another set of parameters.

[0168] During one or more calculation substeps, the periods tbase, tmin, tmax of the acceleration phases A1, A2, A3, and the periods rb, r2, U of the secondary jerk phases can be calculated. These are therefore the periods associated with each portion C1, C2, of the trajectory (for example, the cubic and parabolic portions of the curve C0).

[0169] The trajectory (curve C0) can be based on one or more initial parameters or reference parameters, including at least one acceleration abase, -amin, amax, at least one time datum, at least one velocity, and the value of jerk or j,

[0170] Preferably six initial parameters are defined: the three accelerations abase, -amin, amax, at least one time datum, such as the first period tbase of the first acceleration phase Al, at least one velocity, such as the initial velocity v0 of the drive device 7, and the value of jerk j.

[0171] One or more of these initial parameters can then be used for the calculation of periods tmin, tmax, rb r2, U-

[0172] The method for generating the control signal includes at least one step for establishing or defining the initial parameter(s). At least some of these initial parameters can be freely chosen and established empirically.

[0173] This may be one or more of the following parameters: - the first positive base acceleration during the first acceleration phase Al, - the second acceleration - negative amin during the second acceleration phase A2, - the third positive amax acceleration during the third acceleration phase A3, - the first period tbase of the first acceleration phase Al, - the initial speed v0 of the drive device 7, and - the jerk value j, or jerk value, that is the derivative of the acceleration with respect to time during the secondary phases.

[0174] One or more of these initial parameters can be chosen, for example these six initial parameters, depending on the parts 3 which must advance, be transported by the conveyor 1, in particular depending on their material, and / or their coefficient of friction, and / or their stability in motion.

[0175] It is important that the acceleration values ​​abase, -amin, and amax, and the jerk value j, chosen for calculating the trajectory, are actually physically attainable by the motor, otherwise the trajectory will not be followed correctly and the parts 3 will not be transported optimally. One constraint is to ensure a continuous trajectory without any outliers.

[0176] The initial positive acceleration abase during the first positive acceleration phase Al, or adhesion phase, is chosen according to a compromise. It must be high enough to optimize the speed reached by the transported part 3, but not so high as to prevent the part 3 from being insufficiently driven by the transporting element 5 during the forward movement step El. This acceleration abase is chosen to maximize the driving effect, the adhesion of the part(s) 3 to the transporting element 5. In other words, a limiting acceleration, beyond which adhesion is lost and the part 3 disengages, can be determined, and the acceleration abase can, for example, be chosen to be lower than such a limiting acceleration.

[0177] By way of illustrative and non-limiting example, the first positive acceleration abase during the first acceleration phase Al may be less than or equal to 0.5 g, corresponding in SI units to 4.905 ms 2. Of course, the invention is not limited to this example.

[0178] The first period tbase can be chosen taking into account the effective possible stroke of the transporting element 5, which may, for example, be on the order of a few centimeters, so as not to exceed mechanical stops. The first period tbase of the first positive acceleration phase Al may, for example, be on the order of 20 ms to 100 ms. Of course, the invention is not limited to this example.

[0179] By way of non-limiting example, the second negative acceleration -amin can be on the order of 3g to 5g, or in SI units on the order of 29.43 m.s2 to 49.05 m.s2. Of course, the invention is not limited to this example.

[0180] By way of non-limiting example, the third positive acceleration amax can be on the order of 3g to 5g, or in SI units on the order of 29.43 m.s2 to 49.05 m.s2. Of course, the invention is not limited to this example.

[0181] The initial speed v0 of the drive device 7 can for example be less than or on the order of 300ms*.

[0182] The value of jerk j is defined taking into account that conveyor 1 cannot It is not possible to go from a negative acceleration value to a positive acceleration value instantaneously; two very different acceleration values ​​cannot follow one another.

[0183] The value of jerk j must be chosen sufficiently high to ensure binding between the acceleration values ​​of the different acceleration phases A1, A2, A3 and allow these chosen accelerations to be reached. The second portions C2 of the curve C0 allow the first portions CL to be connected. The higher the jerk value j, the less important the secondary phases are.

[0184] By way of non-limiting example, the value of jerk j or derivative of the acceleration with respect to time during the secondary phases can for example be around 10 million mm.s\ Of course, the invention is not limited to this example.

[0185] The method for generating the control signal includes one or more steps for calculating other parameters or characteristics of the trajectory of the drive device 7, in particular from the established initial parameters. Of course, the calculation can be applied to initial parameters with different values, for example much larger, than the purely illustrative examples given.

[0186] In particular, once the first period tbase is fixed, the periods tmin, tmax, of the two other acceleration phases A2, A3 can be calculated more precisely from the equations developed subsequently.

[0187] Similarly, once the acceleration values ​​abase, -amin and amax of the acceleration phases Al, A2, A3 and of jerk j have been determined, the periods rb r2, L of the secondary phases j can be calculated more precisely from the equations developed subsequently.

[0188] At least one period rb r2, L of a secondary phase can be calculated from at least two of the accelerations abase, -amin, amax and the jerk value or j- value

[0189] The period ti of the secondary phase between the first acceleration phase Al and the second acceleration phase A2 can be determined from the first The positive acceleration abase during the first acceleration phase A1, the negative acceleration -amin during the second acceleration phase A2, and the jerk value j corresponding to the derivative of the acceleration with respect to time during the secondary phases. The period Ti is, for example, calculated using the following formula: ^base^min) = _________

[0190] The period r2 of the secondary phase between the second acceleration phase A2 and the third acceleration phase A3 can be determined from the second negative acceleration -amin during the second acceleration phase A2 and the third positive acceleration amax during the third acceleration phase A3, and from the value of jerk j corresponding to the derivative of the acceleration with respect to time during the secondary phases. The period r2 is, for example, calculated according to the following formula: (pmax+amin)

[0191] The period r3 of the secondary phase between the third acceleration phase A3 and the first acceleration phase Al can be determined from the first positive acceleration abase during the first acceleration phase Al, the third positive acceleration amax during the third acceleration phase A3, and the value of jerk j corresponding to the derivative of the acceleration with respect to time during the secondary phases. It is, for example, calculated according to the following formula: (,amax~alxisi)

[0192] In addition, at least one period tmin, tmax of an acceleration phase A2, A3 can be calculated from at least two of the accelerations abase, -amin, amax, the value of jerk or j, the first period tbase, the initial velocity v0 of the drive device 7 and the periods rb r2, r3 of the secondary phases, in particular calculated as explained above.

[0193] The second period tmin of the second acceleration phase A2 can be calculated according to the following formula: B ^bPaac^) . ^min — 2 A ' 2A

[0194] In this formula, A corresponds to a first coefficient, B to a second coefficient, and Cpr to a third coefficient. These coefficients A, B, Cpr are intermediate calculations used to simplify and streamline the writing of one or more of the formulas, without any real physical meaning.

[0195] The first coefficient A is a function of the second acceleration -amin, negative, during the second acceleration phase A2 and of the third positive acceleration amax during the third acceleration phase A3.

[0196] The first coefficient A can be calculated according to the following formula: - / / - / / / . X A ___ in}ni 1 < A ' 2 amax J

[0197] The second coefficient B is a function of the first positive acceleration abase, the second negative acceleration -amin, the third positive acceleration amax, the first period tbase of the first acceleration phase Al, the initial velocity v0 of the drive device 7, the period Ti of the secondary phase between the first acceleration phase Al and the second acceleration phase A2, the period r2 of the secondary phase between the second acceleration phase A2 and the third acceleration phase A3, and the value of jerk j corresponding to the derivative of the acceleration with respect to time during the secondary phases.

[0198] The second coefficient B can be calculated according to the following formula: jy __ / । ^miii \ I . *£X , j . . — \ ' am«x / \ ^buxirbase J 2 ' ^0 ^min^2 / ' a»iax J 2

[0199] As regards the third coefficient Cpr, it is a function of the first positive acceleration abase, the second negative acceleration -amin, the third positive acceleration amax, the first period tbase, the periods rb r2, the secondary phases between the acceleration phases Al, A2, A3, the initial velocity v0 of the drive device 7, and the value of jerk j corresponding to the derivative of the acceleration with respect to time during the secondary phases.

[0200] The third coefficient Cpr can be calculated according to the following formula: / .Tj .A jt~ Cpr — C + T\ di)aseti,a!ie + ^base^l " J~2 Vq " ^min^2 ^max^3 / + amax~

[0201] In this formula for calculating the third coefficient Cpr, T corresponds to a fourth coefficient and C corresponds to a fifth coefficient.

[0202] The fifth coefficient C is a function of the accelerations abase, -amin, amax during the three acceleration phases Al, A2, A3, of the first period tbase and of the periods rb r2, r3 of the secondary phases, of the initial velocity v0 of the drive device and of the value of jerk j corresponding to the derivative of the acceleration with respect to time during the secondary phases.

[0203] The fifth coefficient C can be calculated according to the following formula: ^base ( 2 ^basé^l 2 ^basé^2 ^"1^2 ^baseT^ ) / A j .n A ^min \ T + T2T3 / + «death " JT ' J 2 ^2 + Tt ' J~T3 + JT T3 ' JT + V^base+T} + T2+T3)-

[0204] The fourth coefficient T is a function of the accelerations abase, -amin, amax during the three acceleration phases A1, A2, A3 of the first period tbase and the periods rb r2, r3 of the secondary phases. It can be calculated according to the following formula: rp _ J 2 2 3 ^ 2 : 3

[0205]

[0206]

[0207]

[0208]

[0209]

[0210]

[0211]

[0212]

[0213]

[0214]

[0215] Furthermore, the third period tmax can also be a function of the second period tmin. The third period tmax, that is, the period of the third acceleration phase A3, can be determined from the second negative acceleration -amin, the third positive acceleration amax, the second period tmin, and the fourth coefficient T. The third period tmax is calculated, for example, using the following formula: * — y ■ hnax — J amax tmi„ The third period tmax is generally less than the second period tmin. In particular, the values ​​of the second period tmin and the third period tmax must be zero or positive. Otherwise, the parameter set would not allow for a solution. The time / period values ​​tbase, tmin, tmax associated with the acceleration phases Al, A2, A3, and rb r2, ^associated with the secondary phases j, defined as developed previously, are unique for a given set of parameters. Once the values ​​of accelerations abase, -amin and amax and of jerk j are defined over a cycle, as well as the associated periods tbase, tmin, tmax, the trajectory can be constructed by successive integrations. A first integration allows us to obtain the speed of the drive device 7, more precisely of the motor, and a second integration allows us to obtain the position P of the drive device 7, more precisely of the motor, during time t. The calculation steps can be automated and performed very quickly. For example, it can take less than a second starting from the six initial parameters described above. Over period T6, the trajectory equation can consist of a predefined number of trajectory segment equations for respective time intervals: tbase, tmin, r2, tmax, t3. To achieve this, the control signal generation process includes at least one calculation step for at least one or each trajectory segment of the drive device 7 according to an associated trajectory segment equation. Each trajectory segment corresponds to a respective time interval. The time interval can be the period tbase, tmin, tmax of at least one acceleration phase A1, A2, A3 or the period r2, L of at least one secondary phase. In particular, six trajectory portions respectively associated with the first period tbase, the second period tmin, the third period tmax and the period rb r2, r3 of each secondary phase, are calculated according to six equations of respective trajectory portions. The equations for sections of the trajectory are a function of time t, the base velocity vbase, and at least one acceleration abase, -amin, amax. One or more trajectory portion equations can also be a function of at least one parameter among: at least one period tbase, tmin, tmax of an acceleration phase Al, A2, A3, the value of jerk j, at least one period rb r2, T? between two acceleration phases Al, A2, A3.

[0216] For the sake of simplifying the writing of the equations for portions of the trajectory, the durations T1, T2, T3, T4, T5 are introduced. These durations begin at time zero t=0.

[0217] A first duration Tl corresponds to the first period tbase during the first acceleration phase Al, i.e.: Tl = tbase.

[0218] A second duration T2 corresponds to: - the first period tbase added to - the period Ti of the secondary phase between the first acceleration phase Al and the second acceleration phase A2, i.e.: T2 = tbase + 7X,

[0219] A third duration T3 corresponds to the sum of: - the first period tbase, - the period Ti of the secondary phase between the first acceleration phase Al, and - the second acceleration phase A2 and at the second period tmin during the second acceleration phase A2, i.e.: T3 = + rl + tmin.

[0220] A fourth duration T4 corresponds to the sum of: - the first period tbase, - the period Ti of the secondary phase between the first acceleration phase Al and the second acceleration phase A2, - the second period tmin, and - the period r2 of the secondary phase between the second acceleration phase A2 and the third acceleration phase A3, i.e.: 7'4 = / iaw + r{ + ^TOi„+T2.

[0221] A fifth duration T5 corresponds to the sum: - the first period tbase, - the period Ti of the secondary phase between the first acceleration phase Al and the second acceleration phase A2, - the second period tmin, - the period r2 of the secondary phase between the second acceleration phase A2 and the third acceleration phase A3, and - the third period tmax of the third acceleration phase A3, i.e.: T5 = ^base + + ^min + r2 + tmax-

[0222] As previously explained, the period T6 of the trajectory corresponds to the sum of the periods of the three acceleration phases Al, A2, A3 and the three secondary phases, T6 = tbase + rl ++ r2 ++ t3.

[0223] A first equation (1) of a portion of the trajectory can be predicted for the first acceleration phase Al, that is to say for the first period tbase (or first duration Tl), i.e. for 0<£ <nou0<f<

[0224] The first equation (1) can be a function of the advancement speed vbase of the drive device 7 during the advancement step El, of the first positive acceleration abase, as well as of the time t.

[0225] This first equation (1) is:

[0226] (1) : x(0< t < TT) = +

[0227] This first equation (1) corresponds to a first portion Cl of the curve C0 of the trajectory during the first acceleration phase Al.

[0228] A second equation (2) of a portion of the trajectory can be provided for the secondary phase between the first acceleration phase A1 and the second acceleration phase A2, that is, for the period rb or the time interval from the end of the first duration T1 to the end of the second duration T2, i.e., for tbase <t^ T2, ou T\<t<T2.

[0229] The second equation (2) can be a function of the advancement speed vbase of the drive device 7 during the advancement step El, of the first positive acceleration abase, as well as of the time t and of the first duration Tl or first period tbase.

[0230] The second equation (2) can also be a function of the result of the first equation (1) for t = Tl, i.e. x(Tl).

[0231] This second equation (2) is:

[0232] (2): x(Tl <t<T2) = x(ri) + ^( / -71) +a^(t-Tl)2 / 2-j(t-TV>3 / 6

[0233]

[0234] This second equation (2) corresponds to a second portion C2 of the curve C0 of the trajectory during the secondary phase of period rb

[0235] A third equation (3) of a portion of trajectory can be provided for the second acceleration phase A2, that is to say for the second period tmin, or the time interval from the end of the second duration T2 to the end of the third duration T3, i.e. for T2 < t < 73.

[0236] The third equation (3) can be a function of the advancement speed vbase of the drive device 7 during the advancement step El, the first positive acceleration abase, the second negative acceleration -amin and the second period tmin, as well as the time t, the value of jerk j, the period Ti between the first acceleration phase Al and second acceleration phase A2, and second duration T2.

[0237] The third equation (3) can also be a function of the result of the second equation (2) for t = T2, i.e. x(T2).

[0238] This third equation (3) of a portion of trajectory is:

[0239] (3): x(T2 <t< T3) =x(T2)+vbase(t-T2) + (ab(tseT2-^12) (t-T2) ^^(1^ / 2

[0240] This third equation (3) corresponds to a first portion Cl of the curve C0 of the trajectory during the second acceleration phase A2.

[0241] A fourth equation (4) of a portion of trajectory can be provided for the secondary phase between the second acceleration phase A2 and the third acceleration phase A3, that is to say for the period r2, or the time interval from the end of the third duration T3 to the end of the fourth duration T4, i.e. for T3 < t < TA.

[0242] The fourth equation (4) can be a function of the advancement speed vbase of the drive device 7 during the advancement step El, of the first positive acceleration abase, of the second negative acceleration -amin and of the second period tmin, as well as of the time t, of the value of jerk j, of the period Ti between the first acceleration phase Al and the second acceleration phase A2, of the second duration T2, and of the third duration T3.

[0243] The fourth equation (4) can also be a function of the result of the third equation (3) for t = T3, i.e. x(T3).

[0244] This fourth equation (4) is:

[0245] (4): x(T3 <t<T4) = x(T3) + ^(^3) + jT] / 2-amintllün) (J-T3)-amin(TT3)2 / 2 +j(t-T3ÿ / 6

[0246] This fourth equation (4) corresponds to a second portion C2 of the curve C0 of the trajectory during the secondary phase of period r2.

[0247] A fifth equation (5) of a portion of trajectory can be provided for the third acceleration phase A3, that is to say for the third period tmax, or the time interval from the end of the fourth duration T4 to the end of the fifth duration T5, i.e. for TA< t < T5.

[0248] The fifth equation (5) can be a function of the forward speed vbase of the drive device 7 during the forward step El, the first positive acceleration abase, the second negative acceleration -amin and the second period tmin, the third positive acceleration amax, as well as the time t, the value of jerk j, the period Ti between the first acceleration phase Al and the second acceleration phase A2, and the period r2 between the second acceleration phase A2 and the third acceleration phase A3, of the second duration T2, and of the fourth duration T4.

[0249] The fifth equation (5) can also be a function of the result of the fourth equation (4) for t = T4, i.e. x(T4).

[0250] This fifth equation (5) of a portion of trajectory is:

[0251] (5): x(T4 <t<T5) = x(T4) + vbase(t-T4) + (abaseT2- !2-amin(t^„ + r2) + jrj / 2) (t-T4) + (t-T4ŸH

[0252] This fifth equation (5) corresponds to a first portion Cl of the curve C0 of the trajectory during the third acceleration phase A3.

[0253] A sixth equation (6) of a portion of the trajectory can be provided for the secondary phase between the third acceleration phase A3 and a new first acceleration phase Al for a new cycle, i.e. for the period r3, or the time interval from the end of the fifth duration T5 to the end of the period T6 of the trajectory, i.e. for T5 <t< T6.

[0254] The sixth equation (6) can be a function of the advancement speed vbase of the drive device 7 during the advancement step El, of the first positive acceleration abase, of the second negative acceleration -amin and of the second period tmin, of the third positive acceleration amax and of the third period tmax, as well as of the time t, of the value of jerk j, of the period Ti between the first acceleration phase Al and the second acceleration phase A2, of the period r2 between the second acceleration phase A2 and the third acceleration phase A3, of the second duration T2, and of the fifth duration T5.

[0255] The sixth equation (6) can also be a function of the result of the fifth equation (5) for t = T5, i.e. x(T5).

[0256] This sixth equation (6) is:

[0257] (6): x(T5 <t<T6) = x(T5) + v base (t-T5) + ( a base T1 ~ 1 2 - a min (Knin + +12 + a rtulx t nulx ) ( tT5 ) + a,^(t-T5} 2 l2-j(t-T5ŸI(>

[0258] This sixth equation (6) corresponds to a second portion C2 of the curve C0 of the trajectory during the secondary phase of period r3.

[0259] Finally, the generation process may include a storage step in which the generated control signal and / or one or more parameters representative of the control signal, such as: one or more equations (1) - (6), at least one of the initial parameters or at least one set of initial parameters, at least one acceleration abase, -amin, amax, at least one time data r2, t3, tbase, tmin, tmax, T1 - T6, at least one speed v0, vbase, vmin, vmax, at least one jolt value, can be stored in the memory of the conveyor control unit 1. According to a particular example, the calculated trajectory, or portions of the calculated trajectory, can be stored, for example as a table of positions, in the memory of the conveyor control unit 1.

[0260] Thus, when a part 3 is placed on the transport member 5, and the motor is driven, so as to follow the trajectory obtained according to the control signal generation process described above, the part 3 advances all the time according to the arrow Fl, it continues to advance by inertia during the recoil step E2 of the drive device 7.

[0261] It has been observed experimentally that the speed of the transported parts 3 is higher the greater the stroke of the motor.

[0262] Moreover, both when part 3 starts its movement with a speed greater than or equal to the initial speed of the drive device 7 and when it starts with a speed less than the initial speed of the conveyor 1, it has been found that the speed of part 3 tends to align at some point with the speed of the drive device 7.

[0263] Thus, calculating the trajectory from the initial parameters, which are physical parameters, allows for adjustment as close as possible to the optimum. The method for generating the control signal as described above makes it easy to parameterize conveyor 1 at any time by adjusting one or more of the initial parameters.

[0264] These initial parameters can be modified at will to generate new trajectories, within the limit of the existence of a solution (for example, a low jerk value j associated with high accelerations would not allow obtaining a solution of the proposed form).

[0265] A new set of these initial parameters can be tested quickly. This offers much greater freedom when adjusting the conveyor 1 than in previous solutions, particularly with a drive cam, and allows adaptation to one type of part 3 to be transported or another.

[0266] For example, for a fragile part 3, these initial parameters can be adjusted so that the conveying element 5 does not move too fast. Conversely, if the parts 3 to be conveyed are quite robust and have a good coefficient of friction, the initial parameters can be adapted to make the conveying element 5 move faster.

[0267] Moreover, the calculation can be done on both a translational dimension and a rotational dimension with the same equations previously developed.

[0268] In summary and as already explained, with this solution, a productivity gain of at least 300% has been observed compared to a prior art solution with a drive cam.

[0269] It is also possible with such a solution to reproduce the trajectory followed by a drive cam according to a prior solution, and in this case a gain of the order of 80% to 100% was observed, attributed to an absence of parasitic vibrations.

[0270] The speed of a transported part 3 can be doubled and be more stable, so that the gap between the parts 3 is also more stable compared to prior art solutions.

[0271] In addition, the motion profile is calculated so as to allow the motor to reach the different acceleration values, in particular thanks to the secondary phases known as jerk phases and therefore to the cubic portions or portions similar to cubic curves of the C0 curve which allow a realistic representation of the trajectory to be obtained.

[0272] Finally, when the parameters have been correctly chosen according to the motor's capabilities and the moving masses, the actual trajectory corresponds well to the setpoint (i.e., the analytical trajectory). According to an example embodiment, the positioning error of the actual trajectory over time is less than ±0.04 mm.

Claims

1. Demands Method for generating a control signal for a conveyor (1) for transporting parts (3), - said conveyor (1) comprising: • a transporting element (5) having a transport surface (51) on which the parts (3) to be transported are intended to be arranged, and • a drive device (7) configured to drive the transporting member (5) according to an asymmetric reciprocating motion, the asymmetric reciprocating motion having a displacement in one direction of advance and a displacement in a direction of recoil opposite to the direction of advance, - said method being configured to generate a control signal of at least one forward step (E1) of the drive device (7) at a forward speed (vbase), of at least one reverse step (E2) of the drive device (7) at a reverse speed, and of at least one direction change step (E', E”) between the forward step (E1) and the reverse step (E2), during the direction change step (E', E”), the forward or reverse speed of the drive device (7) varies until it reaches a zero reversing speed at which the direction of forward or reverse of the drive device (7) changes, - characterized in that the control signal comprises a predefined number of trajectory segments corresponding to at least two acceleration phases (A1, A2) with respective non-zero and constant acceleration values ​​(abase, -amin) over an associated period (tbase, tmin) and at least one secondary phase called a jerk (j) with a non-zero period (t1, t2, t3) between two acceleration phases (A1, A2), the jerk value (j) being the derivative of the acceleration with respect to time and being constant for all secondary phases, in that - at least one direction change step (E', E") is initiated during at least one secondary phase and the change in direction of forward or backward movement occurs during an acceleration phase (A2), the acceleration (-amin) being non-zero and constant, and in that - The process for generating the control signal includes: • at least one step to establish a predefined number of initial parameters from among at least one acceleration (base), at least one time datum, at least one velocity, and one jerk value (j), • at least one calculation step of at least one period (tmin) from at least one of the initial parameters, and • at least one calculation step of at least one portion of the trajectory of the drive device (7) according to a portion of trajectory equation (x(t)) associated for a time interval among the period (tbase) of at least one acceleration phase (Al) and the period (ri) of at least one secondary phase, • the trajectory portion equation being a function of time (t), the speed of advancement (vbase), and at least one parameter among: at least one initial parameter including at least one acceleration (abase), the value of the jerk (j), at least one period (tbase) of an acceleration phase (Al), at least one period (ri) between two acceleration phases (Al, A2).

2. A generation method according to the preceding claim, wherein the control signal defines: a first acceleration phase (Al) with a first positive acceleration (abase) constant over a first period (tbase), - a second acceleration phase (A2) with a second negative acceleration (-amin) constant over a second period (tmin), - a third acceleration phase (A3) with a third positive acceleration (amax) constant over a third period (tmax), and in which: - the initial parameters include the first positive acceleration (abase), the second negative acceleration (-amin), the third positive acceleration (amax).

3. A generation method according to the preceding claim, wherein the second negative acceleration (-amin) and the third positive acceleration (amax) have a respective absolute value which is maximum with respect to the acceleration values ​​reached between two direction change steps (E', E").

4. A generation method according to any one of claims 2 or 3, wherein the first period (tbase) is an initial parameter.

5. A generation method according to any one of the preceding claims, wherein in the advancement step (El), the drive device (7) has a positive initial velocity (v0) which increases according to the first positive acceleration (abase) and which reaches a maximum velocity (vmax), the initial velocity (v0) of the drive device (7) being an initial parameter.

6. A generation method according to any one of the preceding claims, wherein at least one period (ri) of a secondary phase between two acceleration phases (Al, A2) is calculated from at least two accelerations (abase, -amin) and the jerk value (j).

7. Generation method according to claims 4 to 6, wherein: - at least the second or third period (tmin, tmax) is calculated from at least two of the accelerations (abase, -amin, amax), the value of the jolt (j), the first period (tbase), the initial speed (v0) of the drive device (7) and the periods (Tb r2, t3) of the secondary phases, and wherein - the third period (tmax) is a function of the second period (tmin).

8. A generation method according to any one of the preceding claims in combination with claim 2, wherein six trajectory portions respectively associated with the first period (tbase), the second period (tmin), the third period (tmax) and the period (rb r2, r3) of each secondary phase between two acceleration phases (Al, A2, A3), are calculated according to six respective trajectory portion equations.

9. A generation method according to any one of the preceding claims in combination with claim 2, comprising at least one step of calculating a first portion of the trajectory of the drive device (7), corresponding to the first acceleration phase (Al) of the first period (tbase), according to a first equation (1) of the associated trajectory portion (x(t)): (1) :x(0 <r<rto) = vbJ^abJ1l2, - avec vbase, la vitesse d’avancement du dispositif d’entraînement (7) durant l’étape d’avancement (El), - abase, la première accélération positive, - tbase, la première période, - t, le temps.

10. A generation method according to the preceding claim, comprising at least one step of calculating a second portion of the trajectory of the drive device (7), corresponding to the secondary phase between said first (A1) and second (A2) acceleration phases of period (t1), according to a second equation (2) of the associated trajectory portion (x(t)): (2): x(T1 <t<T2) = x( T1 ) + (t-T] ) + ahaw(t-T\)2 / 2 - J(t-TÏ )3 / 6 - avec Tl, une première durée correspondant à la première période (tbase), - T2, une deuxième durée correspondant à la somme de la première période (tbase) et la période (ri) de la phase secondaire entre la première phase d’accélération (Al) et la deuxième phase d’accélération (A2), - vbase, la vitesse d’avancement du dispositif d’entraînement (7) durant l’étape d’avancement (El), - abase, the first positive acceleration, - t, time.

11. A generation method according to the preceding claim, comprising at least one step of calculating a third portion of the trajectory of the drive device (7), corresponding to the second acceleration phase (A2) of the second period (tmin), according to a third equation (3) of the associated trajectory portion (x(t)): (3): x(T2 <t<T3) = x(T2) +vhasSt-T2) + (a^eT2-jr]l2) (t-T2)-a^t-T2)2 / 2 - with T2, the second duration, - T3, a third duration corresponding to the sum of the second duration (T2) and second period (tmin), - vbase, the forward speed of the drive device (7) during the forward step (El), - abase, the first positive acceleration, - -amin, the second negative acceleration, - tmin, the second period, - ti, the period between the first acceleration phase (A1) and the second acceleration phase (A2), - j, the jerk value, - t, time.

12. A generation method according to the preceding claim, comprising at least one step of calculating a fourth portion of the trajectory of the drive device (7), corresponding to the secondary phase between said second (A2) and third (A3) acceleration phases of period (r2), according to a fourth equation (4) of associated trajectory portion (x(t)): (4): x(7'3 < / <7’4) = x(T3) +vbase(t-T3) + (ahaseT2-(t-TT)-ami„(t-T3)2 / 2 j(t-T3Ÿ / 6 - with T2, the second duration, - T3, the third duration, - T4, a fourth duration corresponding to the sum of the third duration (T3) and the period (r2) of the phase secondary between the second acceleration phase (A2) and the third acceleration phase (A3), - vbase, the advancement speed of the drive device (7) during the advancement step (El), - abase, the first positive acceleration, - -amin, the second negative acceleration, - tmin, the second period, - Ti, the period between the first acceleration phase (Al) and the second acceleration phase (A2), - j, the value of the jolt, - t, the time.

13. A generation method according to the preceding claim, comprising at least one step of calculating a fifth portion of the trajectory of the drive device (7), corresponding to the third acceleration phase (A3) of the third period (tmax), according to a fifth equation (5) of the associated trajectory portion (x(t)): (5): x(T4 <t<T5) = x(T4)+VbaseÇt-T4) + + Æ2 / 2) +amax(t-T4)2 / 2 - avec T2, la deuxième durée, - T4, la quatrième durée, - T5, une cinquième durée correspondant à la somme de la quatrième durée (T4) et la troisième période (tmax), - vbase, la vitesse d’avancement du dispositif d’entraînement (7) durant l’étape d’avancement (El), - abase, la première accélération positive, - -amin, la deuxième accélération négative, - tmin, la deuxième période, - amax, la troisième accélération positive, - Ti, la période entre la première phase d’accélération (Al) et la deuxième phase d’accélération (A2),- t2, the period between the second acceleration phase (A2) and the third acceleration phase (A3), - j, the value of the jerk, - t, the time.

14. A generation method according to the preceding claim, comprising at least one step of calculating a sixth portion of the trajectory of the drive device (7), corresponding to the secondary phase between the third acceleration phase (A3) and a new first acceleration phase (A1), of period (x3), according to a sixth equation (6) of the associated trajectory portion: (6): x(T5< r <T6) = x(T5) +vhase(t-T5) + ( ^base^ ~ 2 - O-jnin ( ^min + ^*2 ) f + &maxtmax ) ( ~T5 ) + - avec T2, la deuxième durée, - T5, la cinquième durée, - T6, une période correspondant à la somme des périodes (tbase, tmin, tmax) des trois phases d’accélération (Al, A2, A3) et (ti, t2, t3) des trois phases secondaires, - vbase, la vitesse d’avancement du dispositif d’entraînement (7) durant l’étape d’avancement (El), - abase, la première accélération positive, - -amin, la deuxième accélération négative, - tmin, la deuxième période,- amax, the third positive acceleration, - tmax, the third period, - Ti, the period between the first acceleration phase (A1) and the second acceleration phase (A2), - x2, the period between the second acceleration phase (A2) and the third acceleration phase (A3), - j, the jerk value, - t, the time.

15. A generation method according to any one of the preceding claims, wherein the control signal of the drive device (7) has a fundamental frequency having at least one substantially parabolic or parabolic portion and / or at least one substantially cubic or cubic portion.

16. A generation method according to any one of the preceding claims, comprising a storage step in which the signal of command generated or at least a representative parameter of the control signal is stored in a conveyor control unit (1).

17. A method for controlling a conveyor (1) for transporting parts (3), said conveyor (1) comprising: - a transporting member (5) having a transport surface (51) on which the parts (3) to be transported are intended to be placed, and - a drive device (7) configured to drive the transporting member (5) in an asymmetric reciprocating motion, the asymmetric reciprocating motion having a displacement in a forward direction and a displacement in a reverse direction opposite to the forward direction, - characterized in that the control method is configured to control, according to a control signal generated according to a method for generating a control signal according to one of the preceding claims: • at least one forward step (E1) of the drive device (7) at a forward speed (vbase), • at least one reverse step (E2) of the drive device (7) at a reverse speed,and • at least one direction change step (E', E'') between the forward step (E1) and the reverse step (E2), during the direction change step (E', E''), the forward or reverse speed of the drive device (7) varying until reaching a zero reversing speed at which the direction of forward or reverse of the drive device (7) changes.

18. A control method according to the preceding claim, comprising at least one preliminary step for extracting the control signal or at least one parameter of the control signal stored in a memory of a conveyor control unit (1).

19. Conveyor (1) for transporting parts (3) comprising: a transporting element (5) having a transport surface (51) on which the parts (3) to be transported are intended to be arranged, and a controlled drive device (7), configured to drive the transport member (5) according to an asymmetric reciprocating motion, the asymmetric reciprocating motion having a displacement in a direction of advancement during at least one advancement step (E1) and a displacement in a direction of recoil opposite to the direction of advancement during at least one recoil step (E2), characterized in that the drive device (7) is configured to be controlled according to a control method according to one of claims 17 or 18.

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