Control method for an automatic machine for manufacturing or packaging articles and related automatic machine

Abstract

A control method for an automatic machine for manufacturing or packaging articles (2) comprising the steps of: cyclically processing, by means of a primary control loop (A), a first control contribution (B), which is transmitted to an electric drive (3); cyclically determining, by means of the electric drive (3), the actual kinematic values (CV) of an electric actuator (4) and thus of a movable operating element (5); cyclically calculating, by means of a secondary control unit (9), a second control contribution (C) as a function of the first control contribution (B) and / or the current kinematic values (CV); cyclically injecting, by means of the electric drive (3), to the electric actuator (4), a drive current (DC), which is a function of the second control contribution (C) calculated by the secondary control unit (9).

Description

[0001] CONTROL METHOD FOR AN AUTOMATIC MACHINE FOR MANUFACTURING OR PACKAGING ARTICLES AND RELATED AUTOMATIC MACHINE

[0002] Cross-Reference to Related Applications

[0003] This Patent Application claims priority from Italian Patent Application No. 102024000008860 filed on April 18, 2024, the entire disclosure of which is incorporated herein by reference.

[0004] Technical Field

[0005] This invention relates to a control method for an automatic machine for manufacturing or packaging articles and a related automatic machine

[0006] The term “articles” refers to consumables or semi-finished products. In particular, this invention finds advantageous application in an automatic machine for processing or packaging tobacco industry articles (such as traditional or heat-not- burn cigarettes, filters, electronic cigarettes, cigars, snus). Alternatively, the articles could be food or pharmaceutical articles or sanitary towels.

[0007] This invention is applied, for example, in a machine for processing aerosolgenerating material to form aerosol-generating pieces intended to be components of smoking articles.

[0008] Likewise, this invention finds advantageous but non-limiting application in an automatic machine for packaging smoking articles, for example a wrapping machine producing cigarette packs, and in the method for controlling it by monitoring its actuation, to which the following description will make explicit reference, without any loss of generality thereby, as it may relate to any type of automatic machine for processing or packaging articles.

[0009] Prior Art

[0010] These are known automatic machines for the production or packaging of articles (consumables / finished or semi-finished products).

[0011] Usually, these automatic machines comprise a plurality of movable operating elements that act on articles (e.g. cigarette packs, foodstuffs, sanitary towels, etc.) to change their shape, structure or position. Generally, the movable operating elements are mechanical parts of different shapes and sizes designed to process consumables.

[0012] Increasingly, in recent years, these movable operating elements are moved / operated by means of electric actuators, each of which is connected to a respective electric drive that moves it on the basis of calculations and instructions given by a central control unit, for example a motion controller, a PLC integrating one or an industrial PC.

[0013] Negative feedback control methods (for example, proportional-integral-derivative control: PID) are also known that can react to any positive or negative tracking error by keeping its value close to zero.

[0014] These systems work best for movable operating elements that must move with essentially continuous laws of motion. In addition, for systems with constant inertia, they can sufficiently fulfil their function.

[0015] However, it is often the case that an automatic machine for processing or packaging articles includes movable operating elements with variable inertia (for example, due to the presence or absence of the product at different steps of the element’s movement).

[0016] For these systems, even more so for situations where electric actuators need to be driven with very demanding dynamics (for example, for machine assemblies with alternating motion), open-loop controls with feedforward torque contribution have been developed over the years. These open-loop controls with feedforward torque contribution tell the drive, by calculation of the primary control unit, which forces / torques are required to move the axis along a predefined path / trajectory. In other words, the feedforward “warns” the controller of what torque the system will require.

[0017] In any case, the feedforward torque control is based on an imperfect system model. This means that the feedforward controls often need the help of the feedback control circuit to achieve accurate movement. Specifically, therefore, the feedforward torque control helps to execute most of the movement very quickly, while the feedback controls that co-operate with it are delegated to correct the small errors that remain. As a result, a faster settling time can be achieved than if the torque feedforward control were not used.

[0018] Especially for variable inertia systems, feedforward torque control requires significant calculation capacity on the part of the main controller, since the contribution of the feedforward control is calculated moment by moment based on the current dynamics of the operator element to be moved by the electric actuator. In addition, it is important to calculate the delay time for sending the signal, so that it arrives at the drive at the right time to be processed, compared to when it was calculated by the primary control unit.

[0019] All this makes it particularly complex to implement this type of control for all the electric actuators of the automatic machine (which can now be a few hundred).

[0020] There is, therefore, an apparent need for an automatic machine that can control numerous electric actuators with combined feedforward and feedback control without excessive computational effort and that can simplify the design and management of the control even when there is a format change.

[0021] Description of the Invention

[0022] The purpose of this invention is to provide a control method for an automatic machine for manufacturing or packaging articles and a related automatic machine In accordance with this invention, a control method is provided for an automatic machine for manufacturing or packaging articles and a related automatic machine according to the appended claims.

[0023] The claims describe preferred embodiments of this invention forming an integral part of this description.

[0024] In accordance with one aspect of this invention, the automatic machine for manufacturing or packaging articles comprises: a movable operating element by means of which at least one processing is performed on the articles; an electric actuator, in particular an electric motor, connected, in particular mechanically, to the movable operating element; an electric drive, electrically connected to the electric actuator and configured to deliver a drive current to the electric actuator in order to make the movable operating element perform a motion profile to carry out said processing; a primary control unit, which is configured to manage, at least in part, the operation of the automatic machine and on which a primary control loop is performed.

[0025] The automatic machine preferably comprises a secondary control unit, embedded in the electric drive, on which a secondary control loop is carried out.

[0026] The primary control unit is preferably configured to cyclically process, via the primary control loop, a first control contribution, in particular a position or speed reference value for the electric drive, and to transmit this contribution to the electric drive.

[0027] The electric drive is preferably configured to determine the current kinematic values of the electric actuator and thus of the movable operating element.

[0028] The secondary control unit is preferably configured to calculate a second control contribution by means of a secondary control loop, in particular a feedforward torque contribution, as a function of the first control contribution and / or the current kinematic values.

[0029] In accordance with a particular aspect of the invention, the electric drive is configured to inject a drive current to the electric actuator, the current being a function of the second control contribution calculated by the secondary control unit.

[0030] The drive current is preferably a function, in particular sum, of the second control contribution calculated by the secondary control unit and a feedback contribution calculated as a function of the first control contribution, in particular the position or speed reference value.

[0031] In accordance with one aspect of this invention, the method comprises the step of cyclically processing, via the primary control loop, a first control contribution, which is transmitted to the electric drive.

[0032] The method preferably comprises the step of cyclically determining, by means of the electric drive, the actual kinematic values of the electric actuator and thus of the movable operating element. The method preferably comprises the step of cyclically calculating, by means of the secondary control unit, a second control contribution as a function of the first control contribution and / or the current kinematic values.

[0033] In accordance with one aspect of this invention, the method comprises the step of cyclically injecting a drive current to the electric actuator by means of the electric drive, the current being a function of the second control contribution calculated by the secondary control unit.

[0034] The drive current is preferably a function, in particular sum, of the second control contribution calculated by the secondary control unit and a feedback contribution calculated as a function of the first control contribution.

[0035] Brief Description of the Drawings

[0036] This invention will now be described with reference to the accompanying drawings that illustrate some non-limiting embodiments thereof, in which:

[0037] • Figure 1 illustrates a schematic and perspective view of a possible embodiment of an automatic machine in accordance with one embodiment of this invention;

[0038] • Figure 2 shows a wiring diagram, with parts removed for simplicity, of part of the connections and devices of the machine in Figure 1 ;

[0039] • Figure 3 illustrates an internal control diagram for one of the drives shown in Figure 2;

[0040] • Figure 4 is a flow chart relating to the management of information between a primary control unit and the electric drive in Figure 3;

[0041] • Figures 5 and 6 schematically illustrate comparative graphs of the tracking error between a conventional control method and an embodiment of a control method in accordance with this invention.

[0042] Preferred Embodiments of the Invention

[0043] Figure 1 shows an automatic machine 1 for the production of articles, in particular tobacco industry articles. Specifically, Figure 1 shows an automatic packaging machine 1 for applying a transparent over- wrap to cigarette packs. Obviously, this invention can also apply to different machines for the production or packaging of articles (finished products / consumables or semi-finished products). The automatic machine 1 comprises a frame F, for example made of steel, on which a plurality of movable operating elements 5 (such as grippers, drums, pushers, etc.) are mounted, which perform processing, that is production and / or packaging operations, on the articles (which in the non-limiting embodiment illustrated in Figure 1 are cigarette packs 2).

[0044] The same reference numbers and letters in the figures identify the same elements or components with the same function.

[0045] In the context of the present description the term "second" component does not imply the presence of a "first" component. These terms are in fact used as tags to improve clarity and should not be understood in a limiting way.

[0046] The elements and features disclosed in the various preferred embodiments, including the drawings, may be combined with one another without however departing from the scope of protection of the present application as described below.

[0047] The automatic machine 1 comprises at least one element, in particular a plurality of elements, designed to carry out processing on the articles (cigarette packs 2 in the embodiment illustrated in Figure 1). These elements will be generically referred to as movable operating elements 5 in this description. The term “processing” refers to the mechanical transformation of the article in shape, size, components or position.

[0048] In particular, the automatic machine 1 comprises at least one electric actuator 4, in particular an electric motor, connected (preferably mechanically) to a respective movable operating element 4.

[0049] In addition, the automatic machine comprises at least one electric drive 3, electrically connected to the electric actuator 4 and configured to supply a drive current DC to the electric actuator 4 in order to make the movable operating element 5 perform said processing.

[0050] In other words, therefore, the electric actuator 4 is mechanically connected to a respective movable operating element 5 (also known as the last follower) that performs the processing on the articles (for example on the packs 2). The electric actuator 4 is actually electrically connected to the electric drive 3 and is configured to receive torque from the electric drive 3 in order to make the movable operating element 5 perform a motion profile.

[0051] According to some preferred but non-limiting embodiments, the electric actuators 4 comprise electric motors (particularly brushless ones). According to other embodiments not illustrated, the actuators 4 comprise drive types other than electric motors (for example, electrically actuated cylinders, etc.).

[0052] In some non-limiting examples, the electric drives 3 are grouped in a dedicated area of the automatic machine 1 (for example, a general or dedicated electrical panel). Alternatively or in addition, some electric drives 3 are arranged at the respective electric actuator 4. For example, in the case of an electric motor, the respective drive 3 can be arranged on the stator of the motor. In other words, in some non-limiting cases, the electric drives 3 are arranged in a machine control unit. Alternatively or in addition, some electric drives 3 may be arranged on the respective electric actuator 4 to which they are connected.

[0053] The automatic machine 1 also includes a primary control unit 6 (Figure 1), which is configured to manage at least part of the operation of the automatic machine 1 (both in terms of logics and motion) and is configured to execute a primary control loop A.

[0054] Specifically, therefore, the primary control unit 6 is configured to control the electric actuators 4 via the drives 3. In other words, the control unit 6 is configured to control the electric drive 3 by controlling the motion of the movable operating element 5.

[0055] Advantageously but without imposing limits, the automatic machine 1 comprises an interface device 7 (illustrated in Figure 1) configured to allow an operator O to change the format of the product to be processed or packaged. In particular, the interface device 7 includes a screen 8; more precisely, the screen 8 is a touch screen.

[0056] Advantageously, the primary control unit 6 is also configured to cyclically process, via the primary control loop A, a first control contribution B, in particular a position or speed reference value R for the electric drive 3, and to transmit this contribution to the electric drive 3.

[0057] The electric drive 3 is preferably configured to determine the current kinematic values CV (position, speed, acceleration) of the electric actuator 4 (specifically, electric motor) and thus of the movable operating element 5.

[0058] Specifically, according to some preferred, non-limiting embodiments, the electric drive 3 is pre-programmed with the current kinematic values CV (position, speed, acceleration) of the electric actuator 4 (specifically, electric motor) and thus of the movable operating element 5.

[0059] Alternatively (or in addition, if one wanted a redundant check), the electric drive 3 is configured to detect, moment by moment, the current kinematic values CV (position, speed, acceleration) of the electric actuator 4 (specifically, electric motor) and thus of the movable operating element 5.

[0060] Thus, in some cases, the kinematic values CV are known to the electric drive 3 (after accurate modelling of the movable operating element 5), which performs the steps described below as a function of the kinematic data CV stored in it; whereas, in other cases, the kinematic values CV are detected moment by moment so as to be used by the drive 3 to perform the steps described below as a function of the kinematic data CV it has detected.

[0061] Advantageously, the automatic machine 1 comprises a secondary control unit 9, embedded in the electric drive 3, on which a secondary control loop D is executed. In particular, unlike what happens conventionally, the secondary control unit 9 is also a calculation unit; usually, the calculation is delegated entirely to the primary control unit 6 or to a respective motion controller external to the drive 3.

[0062] The secondary control unit 9 is configured to calculate (and then inject as will be shown below) a second control contribution C, in particular a feedforward torque contribution FF, as a function of the first control contribution B (in particular, as a function of the position or speed reference value R) and / or the current kinematic values CV.

[0063] In other words, therefore, the actuator 4 control calculation is split between the primary unit 6, which calculates the first control contribution B (specifically, the position or speed reference value R), and the secondary control unit 9, which calculates the second control contribution C (specifically, the feedforward torque contribution FF). In this way, the primary control unit 6 can be considerably relieved and, at the same time, the control of the electric actuator 4 can be improved.

[0064] In fact, by doing so, the second control contribution C (that is, the feedforward torque contribution FF), which if the system is well modelled determines most of the drive current DC, will be directly phased with the secondary control loop D, thus disregarding all the anticipation necessary to make the controls for the feedforward torque contribution FF arrive at the correct time from the primary control unit 6, which merely sends a position setpoint (that is, the position or speed reference value R) to the drive 3.

[0065] Finally, the electric drive 3 is configured to inject a drive current DC to the electric actuator 4 that is a function of the second control contribution C (in particular, the feedforward torque contribution FF) calculated by the secondary control unit 9.

[0066] The drive current DC is preferably a function, in particular sum, of the second control contribution C (in particular, the feedforward torque contribution FF) calculated by the secondary control unit 9 and a feedback contribution FB calculated as a function of the first control contribution B (in particular, as a function of the position or speed reference value R).

[0067] According to the preferred but non-limiting embodiment in Figures 1 and 2, the automatic machine 1 comprises a plurality of movable operating elements 5, respective electric actuators 4 and respective electric drives 3, some of which (potentially each of which) in turn comprise a respective secondary control unit 9. In accordance with another aspect of this invention, a control method for an automatic machine for manufacturing or packaging articles is provided.

[0068] Advantageously, the automatic machine 1 is configured to perform the method described below. In particular, the primary control unit 6 and the secondary control unit 9 are programmed to carry out said method. The method comprises the steps of:

[0069] - cyclically processing, by means of the primary control loop A, a first control contribution B, which is transmitted to the electric drive 3;

[0070] - cyclically determining, by means of the electric drive 3, the actual kinematic values CV of the electric actuator 4 and thus of the movable operating element 5;

[0071] - cyclically calculating, by means of the secondary control unit 9, a second control contribution C as a function of the first control contribution B and / or the current kinematic values CV;

[0072] - cyclically injecting, by means of the electric drive 3, to the electric actuator 4, a drive current DC, which is a function, in particular sum, of the second control contribution C calculated by the secondary control unit 9 and of a feedback contribution FB calculated as a function of the first control contribution B. Advantageously but without imposing limits, the first control contribution B is the position (or speed) reference value R for the electric drive 3. Advantageously but without imposing limits, the second control contribution C is preferably the feedforward torque contribution FF as a function of the position (or speed) reference value R and the current kinematic values CV.

[0073] According to some non-limiting embodiments, during the step of cyclically calculating the second control contribution C, the feedforward torque contribution FF is calculated as a function of inertia values IV selected by the secondary control unit 9 from an inertia file 10 according to the current position of the electric actuator 4.

[0074] In particular, the inertia file 10 can be local in a storage unit integrated into the electric drive 3, or come as a signal from the primary control unit 6.

[0075] Preferably but without imposing limits, the feedforward torque contribution FF is calculated by the secondary control unit 9 by multiplying the inertia values IV (or an elaboration thereof) by an acceleration coefficient X and / or a speed coefficient Y (squared) of the electric actuator 4 and / or a gravity coefficient G of the movable operating element 5. Therefore, as is known, the contribution FF is preferably calculated as follows FF=Xa+l / 2(Y)v2+G, where all these factors are a function of the position of the electric actuator 4. In particular, the factor X corresponds to the inertia matrix and the factor Y corresponds to its derivative with respect to the position of the electric actuator 4.

[0076] According to some preferred but non-limiting embodiments, the primary control loop A lasts longer than the secondary control loop D, which lasts at least half as long as the primary control loop A.

[0077] In particular, the duration of the primary control loop A is a multiple of the duration of the secondary control loop D. More specifically, the duration of the secondary control loop D is 500 ps or less, specifically 250 ps or less. The primary control loop A preferably has a duration of 1 ms or more.

[0078] In these non-limiting examples, advantageously, since the secondary control loop D has a higher resolution, in light of the shorter cycle time, compared to the primary control loop A, the secondary control unit 9 interpolates the position (or speed) reference values R received from the primary control unit 6, obtaining intermediate reference values R1and performs the calculating and injecting steps according to the intermediate reference values R1.

[0079] According to what is illustrated in the non-limiting embodiments in Figures 1 and 2, the automatic machine comprises a plurality of movable operating elements 5, respective electric actuators 4 and respective electric drives 3, some of which (potentially each of which) in turn comprise a respective secondary control unit 9. In particular, the primary control unit 6 processes a plurality of position or speed reference values R (one for each actuator 4), each of which is sent to a respective electric drive 3, which will carry out the respective steps of calculating and injecting according to the current position of the respective electric actuator 4.

[0080] In the non-limiting embodiment in Figure 2, a possible connection between the devices of the automatic machine 1 is schematically illustrated. In particular, the primary control unit 6 is visible, which is connected to the screen 8 and electric drives 3, which are in turn connected to the respective electric actuators 4, that is electric motors. In particular, one of the drives 3 illustrated (the one furthest to the left) includes a respective secondary control unit 9, while the other two do not, thus being conventional electric drives 3. Specifically, the electric actuator 4 (that is, electric motor) connected to the drive equipped with the respective secondary control unit 9 moves a movable operating element 5 with variable inertia, while the other electric drives 3 move movable operating elements 5 with constant inertia. More specifically, on the same fieldbus that connects the primary control unit 6 to the drives 3, a series of sensors 11 and / or elements I / O also communicate; these communicate with the primary control unit 6 that oversees the operation of the machine 1.

[0081] Physically, the primary control unit 6 may also consist of a plurality of CPUs located in different positions of the automatic machine 1 and communicating with each other.

[0082] Figures 5 and 6 show graphs of the position error of the electric actuator 4 controlled by the drive 3 equipped with the secondary control unit 9. In particular, the x-axis shows the time T and the y-axis shows the tracking error TE of the actuator 4.

[0083] It was then, surprisingly, noted that the calculation of the feedforward torque contribution FF within the drive 3 allows the tracking error TE to be reduced by an order of magnitude from tenths of a mm to hundredths of a mm.

[0084] Advantageously but without imposing limits, the automatic machine 1 described above provides a particularly effective format change by reparametrising the internal program of the drive 3 for calculating the feedforward torque contribution FF (if necessary, also modifying the inertia file 10).

[0085] In the non-limiting embodiment in Figure 3, a possible connection diagram between the control unit 6, drive 3 and actuator 4 is illustrated. In particular, the primary control unit 6 provides both the position or speed reference value R and the first control contribution B, in the form of the feedback contribution FB, to the drive 3. Eikewise, the secondary control unit 9 processes the second control contribution C within the drive 3, supplying it to the secondary control loop in the form of feedforward torque contribution FF. In particular, as an alternative to what is illustrated, the kinematic data CV, as well as the inertia file 10, could be directly housed in a drive memory unit 3.

[0086] In the non-limiting embodiment in Figure 4, a flowchart of the management of information between a primary control unit 6 (blocks in white) and the electric drive 3 (blocks in grey) is illustrated. In particular, contrary to the state of the art, the calculation of the second control contribution C, that is the feedforward torque contribution FF, is delegated to the secondary control unit 9, which is physically integrated within the electric drive 3 and thus physically separated from the primary control unit 6. Finally, the embodiment in Figure 4 illustrates that, if the secondary control loop D has a higher resolution than the primary control loop A, the secondary control unit 9 interpolates the position (or speed) reference values R received from the primary control unit 6, obtaining intermediate reference values R1and performs the calculating and injecting steps according to the intermediate reference values R1.

[0087] Although the above-described invention makes particular reference to a very specific embodiment, it is not limited to that embodiment, since it includes all those variations, modifications or simplifications that would be obvious to the person skilled in the art, such as: the addition of additional actuators, a different type of automatic machine from a tobacco industry packaging machine, a different shape of the motion profiles, a different order of the method steps, a different number of motors, etc.

[0088] This invention has several advantages.

[0089] Firstly, it improves the control efficiency of the electric motors, especially in the case of variable inertia or demanding dynamics in light of alternating movements. Furthermore, the machine and method described above make it possible to reduce the computational load on the primary control unit, thereby improving its performance.

[0090] In fact, additional advantages of the method in accordance with this invention relate to the fact that only the unmodelled part of the torque, that is any unforeseen variations in inertia, friction and wear, is delegated to the controller PID (that is, the primary control unit 6). Finally, by displacing part of the calculation for controlling the electric actuators, this invention makes it possible to increase the number of electric actuators without any problems, without risking the collapse of the primary control unit 6. LIST OF REFERENCE NUMBERS IN THE FIGURES

[0091] 1 machine

[0092] 2 cigarette packs

[0093] 3 electric drive

[0094] 4 actuator

[0095] 5 movable operating elements

[0096] 6 primary control unit

[0097] 7 interface device

[0098] 8 screen

[0099] 9 secondary control unit

[0100] 10 inertia files

[0101] 11 sensors

[0102] A first control cycle

[0103] B first control contribution

[0104] C second control contribution

[0105] CV kinematic values

[0106] D secondary control loop DC drive current F frame

[0107] FB feedback contribution

[0108] FF feedforward torque contribution

[0109] IV inertia values

[0110] R position or speed reference value R1intermediate reference values T time

[0111] TE tracking error

Claims

C L A I M S1) A control method for an automatic machine for manufacturing or packing articles (2); the automatic machine (1) comprising:- a movable operating element (5) by means of which at least one processing on the articles (2) can be carried out;- an electric actuator (4), in particular an electric motor, mechanically connected to the movable operating element (5);- an electric drive (3), electrically connected to the electric actuator (4) and configured to supply a drive current (DC) to the electric actuator (4) in order to make the movable operating element (5) perform said processing;- a primary control unit (6) which is configured to manage at least part of the automatic machine (1) operation and on which a primary control loop (A) is executed;- a secondary control unit (9), embedded in the electric drive (3), on which a secondary control loop (D) is executed; the method comprising the steps of:- cyclically processing, by means of the primary control loop (A), a first control contribution (B), which is transmitted to the electric drive (3);- cyclically determining, by means of the electric drive (3), the actual kinematic values (CV) of the electric actuator (4) and thus of the movable operating element (5);- cyclically calculating, by means of the secondary control unit (9), a second control contribution (C) as a function of the first control contribution (B) and / or the current kinematic values (CV);- cyclically injecting, by means of the electric drive (3), to the electric actuator (4), a drive current (DC), which is a function of the second control contribution (C) calculated by the secondary control unit (9); preferably, the drive current (DC) is a function, in particular a sum, of the second control contribution (C) calculated by the secondary control unit (9) and of a feedback contribution (FB) calculated as a function of the first control contribution(B).2) The method according to claim 1, wherein the first control contribution (B) is a position or speed reference value (R) for the electric drive (3); and wherein the second control contribution (C) is a feedforward torque contribution (FF) as a function of the position or speed reference value (R) and the current kinematic values (CV).3) The method according to claim 1 or 2, wherein, during the step of cyclically calculating the second control contribution (C), the feedforward torque contribution (FF) is calculated as a function of inertia values (IV) selected by the secondary control unit (9) from an inertia file (10) according to the current position of the electric actuator (4).4) The method according to claim 3, wherein the feedforward torque contribution (FF) is calculated by the secondary control unit (9) by multiplying the inertia values (IV), or an elaboration thereof, by a position coefficient and / or a speed coefficient of the electric actuator (4) and / or a gravity coefficient of the movable operating element (5).5) The method according to any one of the preceding claims, wherein the primary control loop (A) has a duration greater than the secondary control loop (D), which lasts at least half of the primary control loop (A); in particular, the duration of the primary control loop (A) being a multiple of the duration of the secondary control loop (D); in particular, the duration of the secondary control loop (D) being equal to or less than 500 ps, in particular equal to or less than 250 ps; in particular, the primary control loop (A) having a duration equal to or more than 1 ms.6) The method according to claim 2, wherein the secondary control unit (9) interpolates the reference values (R) in position or speed received from the primary control unit (6) by obtaining intermediate reference values (R’) and performs the steps of calculating and injecting according to the intermediate reference values (R’).7) The method according to any one of the preceding claims, wherein theautomatic machine (1) comprises a plurality of movable operating elements (5), respective electric actuators (4) and respective electric drives (3), some of which, in particular each, in turn comprise a respective secondary control unit (9); wherein the main control unit (6) processes a plurality of first control contributions (B), in particular a plurality of reference values (R) in position or speed, each of which is sent to a respective electric drive (3), which will carry out the respective steps of calculating and injecting according to the current position of the respective electrical actuator (4).8) An automatic machine (1) for manufacturing or packing articles (2); the automatic machine (1) comprising:- a movable operating element (5) by means of which at least one processing on the articles (2) can be carried out;- an electric actuator (4), in particular an electric motor, mechanically connected to the movable operating element (5);- an electric drive (3), electrically connected to the electric actuator (4) and configured to supply a drive current (DC) to the electric actuator (4) in order to make the movable operating element (5) perform said processing; a primary control unit (6) which is configured to manage at least part of the operation of the automatic machine (1) and is configured to execute a primary control loop (A); in which the primary control unit (6) is configured to cyclically process, via the primary control loop (A), a first control contribution (B), in particular a position or speed reference value (R) for the electric drive (3), and to transmit this contribution to the electric drive (3) itself; wherein the electric drive (3) is configured to determine the current kinematic values (CV) of the electric actuator (4) and thus of the movable operating element (5); the automatic machine (1) being characterised by comprising:- a secondary control unit (9), embedded in the electric drive (3); wherein the secondary control unit (9) is configured to calculate a secondcontrol contribution (C) by means of a secondary control loop (D), in particular a feedforward torque contribution (FF), as a function of the first control contribution (B) and / or the current kinematic values (CV); wherein the electric drive (3) is configured to inject to the electric actuator (4) a drive current (DC), which is a function of the second control contribution (C) calculated by the secondary control unit (9); preferably, the drive current (DC) is a function, in particular a sum, of the second control contribution (C) calculated by the secondary control unit (9) and of a feedback torque contribution (FB) calculated as a function of the first control contribution (B), in particular of the reference value (R) in position or speed.9) The automatic machine (1) according to claim 8, comprising a plurality of movable operating elements (5), respective electric actuators (4) and respective electric drives (3), some of which in turn comprise a respective secondary control unit (9).

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