IT201800007659A1 - Procedure for determining the position of the actuators of an automatic machine for the production of tobacco industry items - Google Patents

Description

DESCRIPTION

of the industrial invention entitled:

"Procedure for determining the position of the actuators of an automatic machine for the production of articles of the tobacco industry."

TECHNIQUE SECTOR

The present invention relates to a process for determining the position of the actuators of an automatic machine for the production of items for the tobacco industry.

The present invention finds advantageous application in determining the position of the actuators of an automatic packaging machine that produces packets of cigarettes, to which the following discussion will make explicit reference without thereby losing generality.

ANTERIOR ART

An automatic cigarette packaging machine comprises a plurality of actuators which act on the articles to modify their shape, structure or position and each actuator can assume a plurality of different positions.

Generally, the actuators comprise electric motors or pneumatic cylinders and are connected integrally to mechanical parts of different shapes and sizes suitable for processing the articles.

In case of incorrect operation (possibly also due to an incorrect starting position following a technical intervention during which the actuators have been manually moved by an operator) two or more actuators can collide, and therefore can be, in certain cases, cause of interference (mechanical stops) between the mechanical parts connected to them, thus risking to cause the breakage or damage of these mechanical parts or of the articles on which they work.

When starting the automatic machine (for example after a sudden shutdown due to a power failure or at the first start-up after installation) or in the event of an unexpected shutdown (for example due to material breakage or due to a malfunction), the actuators can be found in undefined positions (i.e. not known to their controllers) following the manual intervention of an operator (who has replaced parts or modified the conformation of the machine) and require a procedure to determine their absolute position (with respect to , that is, to fixed components of the machine) for starting the automatic machine.

The absolute position of an actuator (or of the mechanical part connected to it), defined with respect to an inertial reference system (i.e. fixed, in other words integral with the frame of the automatic machine), may differ from the position detected by the actuator controller , which instead refers to the (random) position of the system (typically an encoder type position sensor) which measures the position of the actuator.

In order for the automatic machine to perform its function effectively, the relative position of an actuator is usually compensated during the tuning of the automatic machine. In particular, an offset value is usually added or subtracted from the detected position in order to obtain the absolute position of this actuator according to the formula:

in which it indicates the absolute position of the actuator with respect to a system integral with the frame of the automatic machine, it indicates the detected position of the actuator ("measured position") and indicates the compensation value ("offset") which can be either positive that negative.

Usually, to define the compensation value, systems are specially designed to perform the so-called "mechanical zero" of the actuator. In other words, the idle actuator (i.e. not in torque, therefore without current) is manually brought by an operator against a mechanical stop or in a pin position (position defined in the design phase and unique that allows a metal pin to enter a suitable housing). These processes are particularly complex in the case of very heavy or inaccessible actuators.

Generally, the definition of the compensation value is therefore a costly operation in many respects. It requires dedicated designs and special materials (for the pins) worked with expensive techniques due to the high precision necessary in defining the compensation value of each actuator (the tolerance between a pin and the respective hole to accommodate it must be particularly accurate. ). Furthermore, on board an automatic machine with a plurality of actuators, several pins of different sizes and accuracies are often required, with possible confusion for inexperienced operators or production delays in case of loss of one of these pins.

Consequently, the definition of the compensation value is usually a very long operation, which requires at least one operator and which affects the delivery, installation and recovery time (for example after a failure with relative replacement of a part) of the automatic machine.

DESCRIPTION OF THE INVENTION

The purpose of the present invention is to provide a method for determining the position of the actuators of an automatic machine for the production of articles of the tobacco industry that is free from the drawbacks described above and, at the same time, is simple and economical to make.

In accordance with the present invention, a method is provided for determining the position of the actuators of an automatic machine for the production of articles of the tobacco industry according to what is claimed in the attached claims. An automatic machine for the tobacco industry is also supplied to carry out the aforementioned procedure.

The claims describe preferred embodiments of the present invention forming an integral part of the present description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the attached drawings, which illustrate some non-limiting examples of implementation, in which:

• figure 1 is a perspective and schematic view of an automatic machine for the production of items for the tobacco industry;

Figure 2 is a schematic view of part of the automatic machine of figure 1 in which there are two actuators;

Figures 3, 4 and 5 are respectively three plan views of the machine part of figure 2 which illustrate different steps of the process for determining the position of the two actuators of the automatic machine part of figure 2;

Figure 6 illustrates a possible interference matrix relating to the machine part of figure 2;

Figure 7 illustrates a possible flow diagram of the method for determining the position of an actuator of a part of an automatic machine in which two actuators are present; And

Figure 8 is a schematic view of a variant of the machine part of figure 2 in which three actuators are present.

PREFERRED FORMS OF IMPLEMENTATION OF THE INVENTION

Figure 1 illustrates an automatic machine 1 for the production of articles of the tobacco industry, in particular an automatic packaging machine 1 for applying a transparent overwrapping to packets of cigarettes. According to a first aspect of the present invention, a method is provided for determining the position of the actuators of at least a part of the automatic machine 1.

The automatic machine 1 comprises various parts suitable for carrying out processing on the articles (packets 4 of cigarettes in the embodiment illustrated in Figure 1). In particular, the automatic machine 1 comprises a part 2 provided with a set (at least two) of actuators 8 and 9, each of which can assume a plurality of different positions.

According to some preferred but not limiting embodiments, the actuators 8 and 9 comprise electric motors (in particular of the brushless type). According to further embodiments not illustrated, the actuators 8 and 9 also comprise types of drives other than electric motors (for example pneumatic or hydraulic cylinders, electrically actuated cylinders, etc.).

Part 2 of the automatic machine of figure 1 is shown schematically and frontally in figures 2, 3, 4 and 5. This part 2 comprises: a wheel 5 rotatably mounted around a central rotation axis A and provided with seats 6 (in particular pockets) adapted to receive the packets 4 of cigarettes and (at least) a pusher 7 adapted to push the packets 4 of cigarettes into the seats 6 of the movable wheel 5.

In the non-limiting embodiment illustrated in Figures 2, 3, 4 and 5, there are two actuators 8 and 9: a first actuator 8 is coupled to the wheel 5 to control the rotation of the wheel 5 around the rotation axis A and is provided with a rotating electric motor (for example of the brushless type) which rotates the wheel 5 through the interposition of a reducer (not shown); a second actuator 9 is coupled to the pusher 7 to control the linear displacement of the pusher 7 along a direction D and for a predefined stroke S (figure 2) and is provided with a rotating electric motor (for example of the brushless type) and of a reducer which transforms the circular movement into linear movement (alternatively the second actuator 9 could comprise a linear electric motor or a pneumatic / hydraulic cylinder).

The part 2 of the automatic machine 1 therefore has two actuators 8 and 9 which can generate interference (or interference) positions. With the terminology "interference positions" (or "interference") we mean all those combinations of positions of the actuators 8 and 9 that generate collisions between the mechanical components of the automatic machine 1 (for example between the wheel 5 and the pusher 7 and / or a package 4 which is interposed between the wheel 5 and the pusher 7).

In some cases, an actuator 8 or 9 may be in positions which do not allow the other actuator 9 or 8 to move freely (i.e. they do not allow the other actuator 9 or 8 to assume any of its possible positions) as they would generate some collisions.

In figure 5, the actuator 8 of the wheel 5 is in a position in which the pusher 7 is not allowed to enter with the product (pack 4 of cigarettes) in one of the seats 6. Consequently, the actuator 9 of the pusher 7 cannot move freely (i.e. it cannot make the pusher 7 assume any of its possible positions along the stroke S) since it could generate a collision between the pusher 7 and the wheel 5, since the wheel 5 is located in a position not suitable for the insertion of the pack 4 of cigarettes in the seat 6 by the pusher 7. In other words, given the position of the actuator 8 of the wheel 5, if the actuator 9 of the pusher 7 moves along its stroke S to try to insert the pack 4 of cigarettes inside one of the seats 6, the pack 4 of cigarettes first, and eventually the pusher 7 then, would collide with the wheel 5, generating waste of material and a possible / probable breakage of c mechanical components. However, this combination of positions of the actuators 8 and 9 allows free movement of the actuator 8 of the wheel 5, since, by turning the wheel 5, it would not cause any collision between the wheel 5 and the pusher 7 or a packet 4 of cigarettes.

In other cases, however, an actuator 8 and 9 may be in positions that allow the other actuator 9 or 8 to move freely (i.e. allow the other actuator 9 or 8 to assume any of its possible positions) without generating collisions. .

As shown in Figure 4, the actuator 8 of the wheel 5 is in a position in which the pusher 7 is allowed to enter with the product (pack 4 of cigarettes) into one of the seats 6. Consequently, the actuator 9 of the pusher 7 can move freely (i.e. it can assume any of its possible positions) without generating any collision between the pusher 7 and the wheel 5, since the wheel 5 is in a position suitable for inserting the pack 4 of cigarettes in the seat 6 by the pusher 7. In other words, given the position of the actuator 8 of the wheel 5, if the actuator 9 of the pusher 7 moves along its stroke S to insert the packet 4 of cigarettes inside one of the seats 6, would not generate any collision between the pack 4 of cigarettes and / or the pusher 7 with the wheel 5. However, this combination of positions of the actuators 8 and 9 does not allow free movement to the actuator 8 of the wheel 5, in how much, f turning the wheel 5 would cause a collision between the wheel 5 and the packet 4 of cigarettes if the packet 4 of cigarettes was only partially inserted in the seat 6, or it would cause a collision between the wheel 5 and the pusher 7 in the case in which the pack 4 of cigarettes was completely inserted and the pusher 7 was partially inside the seat 6. In both cases it would be necessary to stop and reset the automatic machine 1 and in the second case a breakage of mechanical components would also be probable. In Figure 6, the number 10 indicates as a whole an interference matrix which provides for each position of the two actuators 8 and 9 the presence or absence of interference (or interference) positions with respect to all the possible positions of the other actuator 9 and 8.

Advantageously but not necessarily, the interference matrix 10 has a dimension for each actuator 8 or 9. That is, in the interference matrix 10 all the possible positions (0 ... n8) of the actuator 8 of the wheel 5 are shown on the ordinate axis and on the abscissa axis all the possible positions (0 ... n9) of the actuator 9 of the pusher 7. In other words, the movement of each actuator 8 or 9 corresponds to the movement along a dimension of the interference matrix 10, therefore along the axis of the ordinates for the actuator 8 and along the axis of the abscissa for the actuator 9.

In particular, each actuator 8 or 9 can be operated by a control unit 15 in both directions of the corresponding dimension (ordinates and abscissas respectively) of the interference matrix. More particularly, at least one actuator 8 or 9 carries out test displacements in both directions.

The entire stroke of each actuator 8 or 9 is divided into a finite number n8 and n9 of positions and this finite number n8 and n9 of positions is arbitrary and depends on the degree of resolution that is desired: for example in the case of actuator 8 of the wheel 5 it is possible to operate freely along the entire angle of rotation and therefore the stroke of the actuator 8 can be divided into 360 positions (1 ° away from each other), it can be divided into 72 positions (5 ° away from each other). on the other), or it can be divided into 720 positions (0.5 ° away from each other); on the other hand, in the case of the actuator 9 of the pusher 7 the stroke S can be divided into positions 1 mm away from each other, into positions 1 cm away from each other, into positions 0.2 mm away from each other ... interference matrix 10 of Figure 6 some rows and some columns are indicated by dashes, i.e. to indicate the possible presence of a different number of rows or columns depending on the desired resolution for each actuator 8 and 9. Generally, the resolution used for each actuator 8 and 9 is approximately equal to the accuracy of the actuator 8 and 9 itself, ie it makes no sense to use a resolution of the order of microns if an actuator 8 or 9 has an accuracy of the order of centimeters and vice versa.

The interference matrix 10 is provided with a plurality of boxes 11, each of which therefore relates to a pair of positions of the actuators 8 and 9, i.e. it relates to a corresponding position of the actuator 8 associated with a corresponding position of the actuator 9. Given a position of the actuator 8 or 9, the interference matrix 10 defines, on the basis of this position of the actuator 8 or 9, whether for each position of the actuator 9 or 8 (which together form a row or column of the interference matrix 10) an interference condition (position) occurs between mechanical parts in part 2 of automatic machine 1.

The interference matrix 10 therefore has a number of boxes 11 equal to the product of the number of positions of the actuators 8 and 9 (ie the product between the number n9 of rows and the number n8 of columns). In particular, an "X" value may or may not be present within each box 11. The value "X" inside a box 11 indicates that the relative pair of positions determines an interference (and that therefore that pair of positions is not allowed), since, if it were to verify that both actuators 8 and 9 are in those positions there would be a mechanical collision between mechanical elements (for example between wheel 5 and pusher 7) or between mechanical elements and an article (for example between wheel 5 and a pack 4 of cigarettes).

Obviously the “X” value can be replaced by any other predefined value, image or symbol having the same function of providing information on the presence of interference given the positions of the actuators 8 and 9.

According to the non-limiting embodiment illustrated in Figure 6, the absence of the value "X" within a box 11 indicates that the relative pair of positions of the two actuators 8 and 9 does not cause interference. In other words, the lack of the value "X" inside a box 11 determines that that pair of positions is allowed, as no element of the automatic machine 1 would involuntarily collide with another element. The procedure for determining the position of the actuators 8 and 9 of the part 2 of the automatic machine 1 provides for determining an interference matrix 10 which provides for each absolute position of the actuator 8 the presence or absence of interference with respect to all possible positions absolute values of actuator 9 (and vice versa). By "absolute position" we mean the position of an actuator 8 or 9 (or of the mechanical part connected to it) with respect to an inertial reference system (ie fixed, in other words integral with the frame of the automatic machine 1).

The procedure involves measuring a detected position of the actuators 8 and 9, where "detected position" means the position of an actuator 8 or 9 with respect to the (random) position of the system (typically an encoder-type position sensor) which measures the position of actuator 8 or 9. In other words, the detected position corresponds to the digital value detected by the encoder without it being filtered or compensated.

Furthermore, the method provides for operating at least one actuator 8 or 9 to make the actuator 8 or 9 itself perform, starting from the detected position, a test movement having a predefined stroke or, alternatively, having a stroke lower than the predefined stroke. due to reaching an interference position. In other words, the actuator 8 or 9 is operated by the control unit 15, which is aware of the detected position of the actuator 8 or 9, in order to perform a predefined movement (which depends on the type of actuator 8 or 9 and the distances it can travel). In particular, the actuators 8 and 9 can be operated by the control unit 15.

The method comprises the further step of detecting, by means of a control system 3 (in particular included in the control unit 15 as shown schematically in Figure 1) and during the test displacement, the force or torque (respectively for linear motors or rotary) necessary to operate the actuator 8 or 9. In particular, since the actuators 8 and 9 are electric motors, this force or torque control corresponds to a current control (which is directly proportional to the torque or force generated from an electric motor).

The procedure also comprises the step of determining whether an interference position has been reached, which occurs if, during the test movement, the current (and therefore the force or torque) necessary to operate the actuator 8 or 9 exceeds a threshold value. In the event that this threshold value is exceeded, the control system 3 communicates to the control unit 15 of the actuators 8 and 9 to interrupt the operation of the actuator 8 or 9. In other words, in the event that, during the test movement, the threshold value is exceeded, i.e. an interference position has been reached, i.e. the actuator 8 or 9 that is making the test movement has encountered an obstacle (which requires more effort, i.e. more current, compared to an unobstructed condition, to continue the movement).

Advantageously but not necessarily, during the test movement it is verified, in particular by the control system 3, that the value of the current (and therefore the force or torque) of each electric motor (actuators 8 and 9) falls within a predefined tolerance range delimited by an upper threshold value and a lower threshold value. In this way it is possible to detect both an interference (in the case in which the value of the current of an electric motor exceeds the upper threshold value) and the breakdown of a mechanical part (in the case in which the value of the current of an electric motor is lower than the lower threshold value, in this case in fact the load of an electric motor, therefore the current necessary to move it, is lower than expected).

Finally, the method comprises the step of using the interference matrix 10 to uniquely determine the absolute position of the actuators 8 and / or 9 on the basis of the results obtained from the test displacements.

Advantageously but not necessarily, the actuators 8 and 9 are operated sequentially, or one after the other.

Advantageously but not necessarily, the method for determining the position of the actuators 8 and 9 provides for storing the interference matrix 10 in a memory 14 of the control unit 15 (schematically illustrated in Figure 1) of the automatic machine 1 which is adapted to drive actuators 8 and 9.

According to some non-limiting embodiments, the step of storing the interference matrix 10 in the memory 14 of the control unit 15 occurs after the control unit 15 has processed the interference matrix 10 to be used for the method for determining the position of the actuators 8 and 9. According to other non-limiting embodiments, the step of storing the interference matrix 10 in the memory 14 of the control unit 15 occurs after the interference matrix 10 has been processed by a device external to the machine 1 automatic. Consequently, the interference matrix 10 can also be processed off-line, without the need to be connected to the automatic machine 1. This feature can be very useful if a customer wishes to autonomously change the format or implementations of the automatic machine 1, since it would be possible to supply him, even remotely, with a new interference matrix 10 which adapts to the changes made.

Advantageously but not necessarily, the step of determining the interference matrix 10 includes the further steps of: estimating all the possible positions of each actuator 8 or 9 independently of the other actuator 9 or 8; and simulate the possible positions of each actuator 8 or 9 simultaneously with the positions of the other actuator 9 or 8. In this way, it is possible to define the interference matrix 10 already in the design phase, even before the automatic machine 1 is assembled, wired and turned on. In particular, the estimation of the positions of each actuator 8 and 9, as well as the simultaneous simulation with the positions of the other actuator 9 or 8, are carried out through assisted programming systems (CAD - CAE). Assisted programming systems allow to simulate and develop automatic machines in three-dimensional virtual environments and are widely used, consequently they can be used as a basis for the definition of interference positions.

According to some non-limiting embodiments, the interference matrix 10 distinguishes, for each actuator 8 or 9, the interference positions on the basis of a digital (binary) value, i.e. the boxes 11 of the interference matrix 10 each contain a corresponding value digital (binary) which can assume only the “X” value (presence of interference) or only the empty value (absence of interference).

According to other non-limiting embodiments, the interference matrix 10 distinguishes, for each actuator 8 or 9, the interference positions on the basis of an analog value (i.e. which can assume more than two values), i.e. the boxes 11 of the matrix 10 of interference each contain a corresponding analog value that can assume values between a minimum value (complete absence of interference) and a maximum value (certain interference) and therefore can assume intermediate values that indicate a more or less possible / probable interference or they quantify the "safety distance" from an interference. In particular, in this way it is possible to give a weight to the values within the boxes 11 on the basis of a predefined parameter (such as the distance from a possible collision position, in the event that safety is preceded by performance).

According to further non-limiting embodiments, the interference matrix 10 distinguishes, for each actuator 8 or 9, the interference positions on the basis of a combination of digital (binary) and / or analog values.

Advantageously but not necessarily, following the unambiguous determination of the absolute position of an actuator 8 or 9, the position detected by a position sensor coupled to the actuator 8 or 9 itself is updated by means of a compensation value so that it coincides with the absolute position determined. In particular, a compensation value (positive or negative) is added to the detected position in order to obtain the absolute position of this actuator 8 or 9 according to the formula:

in which it indicates the absolute position of the actuator 8 or 9 with respect to a system integral with the frame of the automatic machine, indicates the detected position of the actuator ("measured position") and indicates the compensation value.

In some non-limiting cases, the position of a linear actuator, as shown in figure 3 for the actuator 9, can be determined even in the absence of other actuators, in particular if there is a fixed mechanical stop located on the opposite side with respect to an operating position of the actuator (for example arranged on the opposite side with respect to the pack 4 of cigarettes). In these cases it is possible to determine the position of the actuator 9 by commanding a movement along the direction D in the direction opposite to the wheel 5. As soon as the actuator 9 meets the mechanical stop (i.e. a limit switch), the absolute position of the actuator 9 is uniquely determined and its relative position is compensated according to the formula described above.

However, this procedure cannot be carried out in most cases, in particular in cases where there are no limit switches or in which the motors are rotary or linear operating on both directions of their stroke.

According to what is illustrated in the non-limiting embodiment of Figure 6, the result of the test displacements of the actuator 8 or 9 depends on the test displacements of the actuator 9 or 8 which has zones of interference in the actuator 8 or 9. In in particular, if the result of the test displacements of the actuator 9, in particular along the abscissa axis of the interference matrix 10, does not allow to uniquely determine its absolute position (of the actuator 9), the actuator 8 performs a relocation displacement R, in particular a displacement along the ordinate axis of the interference matrix 10, before the actuator 9 performs a further test displacement. By way of example and with reference to the non-limiting case illustrated in Figure 6, to determine the position of the actuators 8 and 9, the actuator 9 which carries out a test movement having a predefined stroke along the direction D (which corresponds to a movement along the abscissa axis within the interference matrix 10).

Advantageously but not necessarily, the travel of the test movement is optimized on the basis of the actuator 8 or 9 that performs it.

In the non-limiting case of the actuator 9, the test displacement corresponds to the maximum stroke that the actuator 9 performs within its production cycle, in particular the stroke S illustrated in Figure 2. This maximum stroke is usually known since, in design phase, the number of steps of the selected encoder position sensor, the parameters of the gearbox and the stroke to be performed are known; consequently, it is possible to derive the number of encoder steps that are necessary to travel the stroke S.

During the test movement, the control unit 15 knows the detected position of the actuator 9, and performs the test movement starting from that detected position, regardless of the fact that it does not coincide with the absolute position. The control system 3 carries out a current control (therefore of force or torque) verifying if the actuator 9 reaches an interference position by encountering an obstacle.

In some cases, the actuator 9 encounters an obstacle and is stopped by the control unit 15 (following a communication from the control system 3 that certifies that the threshold value has been exceeded by the current impressed on the actuator 9 ). In other cases, such as that shown in Figure 6, the actuator 9 does not encounter obstacles during the test movement along the direction D starting from a position 12, therefore it defines a result that does not allow to uniquely determine the position of the actuator 9 Consequently, in particular at the end of the test movement of the actuator 9, the actuator 8 performs a relocation movement along a direction R, i.e. along the abscissa axis of the interference matrix 10 (in other words a rotation around axis A), before the actuator 9 performs a further test movement. By repeating iteratively test movements by the actuator 9 and repositioning movements by the actuator 8 (respectively along the directions D and R) it is possible to uniquely determine the position of the actuator 9, since, referring to figure 6, after a certain number of relocation movements by the actuator 8, the actuator 9 will necessarily encounter interference zones, allowing to know exactly the position of the actuator 9. In some advantageous non-limiting cases, the relocation movement corresponds to a distance equal to a row of the interference matrix 10. In this way, it is possible to probe the interference matrix 10 in its entirety (also varying the direction of the relocation displacements) in order to determine the absolute position of the actuators 8 and 9, in particular by exploiting the fact that the relocation displacement carried out by the The actuator 8 corresponds to a distance equal to a row of the matrix 10. For example, in the matrix 10, the third test movement by the actuator 9, therefore after the second relocation movement by the actuator 8, the actuator 9 itself will encounter an interference zone indicated by the symbol "X", allowing the control unit to uniquely determine the absolute position of the actuator 9 on the basis of the results of the last test movement and of the previous test and test movements. relocation.

Once the absolute position of the actuator 9 has been determined, the control unit 15 moves the actuator 8 in order to uniquely determine its absolute position through the interference matrix 10. The procedure described above is repeated alternating test displacements, this time of the actuator 8 and corresponding to the displacement along a column of the interference matrix 10, and relocation displacements, this time of the actuator 9 and corresponding to the displacement along a row within the interference matrix 10. In the non-limiting case of the actuator 8, the test displacement corresponds, unlike the case of the actuator 9, to a minimum displacement. In this way, by alternating movements of a row (actuator 8) and a column (actuator 9) it is possible to uniquely determine the position of the actuator 8 on the basis of the interference matrix 10. In other words, to determine the position of the actuator 8 (if it is free to move and therefore the pusher 7 is not inside it), the wheel 5 and therefore the actuator 8 performs a very slight rotation around the axis A followed by an attempt by the pusher 7 and therefore the actuator 9 to enter seat 6.

By repeating this process, sooner or later the pusher 7 will be able to enter one of the seats 6 and therefore the position of the wheel (if the seats 6 are symmetrical) is easily determined. If the seats 6 are not symmetrical, it is possible to repeat the same procedure (attempts to enter the pusher 7 followed by a slight rotation of the wheel 5) for the entire circumference of the wheel, in order to determine the positions of all the seats 6 and consequently determine the absolute position of the wheel 5.

Advantageously but not necessarily, the result of the test movements allows to identify, within the interference matrix 10, one or more search areas. By way of example, with reference to what is illustrated in Figure 6, once the first test movement has been carried out (having a stroke for example corresponding to five boxes 11) by the actuator 9 along the direction D starting from position 12, the The search area within which the possible absolute positions of the actuator 9 are found is zone 18. If, on the other hand, one starts from a position 13, the first test movement by the actuator 9 along the direction D would end with the reaching of an interference zone in which the boxes 11 contain the symbol X. In this case, being aware only of the detected position of the actuator 9 and of the fact that after a certain distance (in this case equivalent to four boxes 11) the actuator 9 has encountered an interference zone, the search areas within which the possible absolute positions of the actuator 9 are located are the zones 19.

Advantageously but not necessarily, the search area contracts (in particular it does not increase) progressively as the number of test movements performed by the actuators 8 and 9 increases, up to the unambiguous determination of the absolute position of each actuator.

In further non-limiting cases, the relocation displacement corresponds to a preset distance equal to a multiplicity of rows of the interference matrix 10. Obviously, what has been said with reference to the rows of the interference matrix 10 is also valid if the columns.

Advantageously but not necessarily, therefore, the result of the test movements of the actuator 9 depends on the movements of the actuator 8 which has areas of interference with the actuator 8.

Figure 7 illustrates a possible and non-limiting flow chart of the procedure for determining the position of an actuator 8 or 9 of part 2 of the automatic machine 1 in which two actuators 8 and 9 are present, and in particular for determining the position of the actuator 9 of part 2 of the automatic machine 1 of figure 2.

In this flow chart, the rectangular blocks are processing blocks in which operations are carried out by the control unit 15, while the rhomboid blocks are six control or verification blocks in which certain conditions are verified; at the output of these blocks, the solid arrows indicate that these conditions are verified, while the dashed arrows indicate that these conditions are not verified.

The number 20 indicates the starting block of the procedure. Inside block 21 the actuator 9 performs a test movement along a direction of direction D. Block 22 checks if the actuator 9 has encountered an obstacle (and therefore an interference zone). Both in the affirmative and in the negative case, the blocks 23A and 23B save the result of the test movement (in particular in order to restrict the search areas more and more) inside the memory 14 and the blocks 24A and 24B check whether the absolute position of the actuator 9 is ambiguous (ie not determined) or not. If the actuator 9 has encountered an obstacle but the position of the actuator 9 is still ambiguous, one passes to block 25, in which the actuator 9 carries out a test movement along the other towards the direction D. Block 26 ( like block 22) checks whether the actuator 9 has encountered an obstacle (and therefore an interference zone); if so, block 27 saves the result of the test movement within memory 14 (in particular in order to increasingly narrow the search areas). If, at the exit from block 24A the position of the actuator 9 is still ambiguous, one enters block 28, in which the actuator 8 performs a relocation movement which corresponds to the movement of a row in the interference matrix 10. Block 29 checks whether an obstacle has been found downstream of the relocation movement by the actuator 8. In the affirmative case, one proceeds, in block 30, with the saving of the result (in particular in order to restrict the search areas more and more) in memory 14. In the negative case, one returns to block 21 and the procedure is repeated, this time on a different row of the interference matrix 10 due to the relocation movement carried out by the actuator 8. The block 31 once again checks whether the position whether the absolute position of the actuator 9 is ambiguous (ie not determined) or not. If so (ambiguous position) block 32 modifies the direction of the relocation movement of the actuator 8 and proceeds to re-analyze the interference matrix 10. If, on the other hand, the position is not ambiguous, all the check blocks lead to block 33 which uniquely determines the absolute position of the actuator 9 and sets the compensation value. Block 34 indicates the end of the procedure for determining the absolute position of the actuator 9.

The non-limiting flow diagram just described can obviously be repeated to determine the absolute position of the actuator 8 and more generally for all the actuators of any part of a machine which present interference and for which a matrix of interference.

Obviously, the procedure described so far for simplicity with only the two actuators 8 and 9 is applied in the same way also in the case of three or more actuators: instead of using two-dimensional interference matrices 10, interference matrices 10 are used a three or more dimensions.

Figure 8 illustrates a non-limiting embodiment of the present invention in which there are three actuators: in addition to the previously described actuators 8 and 9 connected respectively to the wheel 5 and to the pusher 7, there is a further actuator 16 mechanically connected to an accompanying device 17. The accompanying person 17 is able to accompany the packet 4 of cigarettes, together with the pusher 7, inside the seat 6 (pocket) of the wheel 5. In this way the correct orientation of the packet 4 is ensured during insertion and to prevent the packet 4 from getting stuck on the walls of the seat According to some non-limiting embodiments, the interference matrix has a dimension for each actuator 8, 9, 16. Referring to figure 6, it can in fact be noted that the matrix 10 of interference has two dimensions since only the actuators 8 and 9 are present. In the case in which, as for the embodiment of figure 8 , there are three actuators 8, 9 and 16, the interference matrix (not shown) would be three-dimensional, with a dimension for each actuator 8, 9 or 16 indicating all the possible positions of the actuator 8, 9 or 16.

Therefore, in general, if part 2 of automatic machine 1 has “k” actuators, the relative interference matrix will have “k” dimensions. By defining as ni the number of possible positions of an i-th actuator (in the case of figure 6 n8 indicates the number of positions of the actuator 8 while n9 indicates the number of positions of the actuator 9), the quantity Q of boxes indicating positions of interference or non-interference will be equal to:

The number of positions of an i-th actuator ni, can be less than or equal to the actual number of positions that the i-th actuator can take. Obviously, the higher ni is, the higher the resolution of the process.

According to some non-limiting embodiments, the positions of each actuator 8, 9 or 16 are limited to the number 360, so that the entire stroke S of the pusher 7, as well as a complete rotation of the wheel 5, are divided into 360 parts , so that the interference matrix 10 has 360 rows and 360 columns (in the case of two-dimensional interference matrix 10).

According to other non-limiting embodiments, the automatic machine 1 is divided into groups, each of which comprises a pair of actuators and a corresponding two-dimensional interference matrix is defined for each group. In the embodiment of Figure 8, three groups can therefore be identified: a first group formed by actuators 8 and 9, a second group formed by actuators 8 and 16, and a third group formed by actuators 9 and 16. For each group respectively defined two-dimensional interference matrices.

According to some non-limiting embodiments, the two-dimensional interference matrices are used individually for the definition of the absolute positions of the actuators 8, 9 and 16 with the same methods previously illustrated in the case of the interference matrix 10 only for the two actuators 8 and 9 (figure 6).

According to further non-limiting embodiments, the two-dimensional interference matrices can be combined with each other to form an overall interference matrix.

According to a further aspect of the present invention, an automatic machine 1 is provided for the production of articles of the tobacco industry. The automatic machine 1 comprises the (or a plurality of) actuators 8 and 9, each of which can assume a plurality of different positions; a plurality a plurality of detection systems, in particular position sensors (encoders) coupled to the actuators 8 and 9, for detecting the detected position of each actuator 8 and 9; a control system 3 adapted to detect, during a test movement, the force or torque necessary to actuate an actuator 8 or 9 to determine whether an interference position has been reached or not; and a control unit 15 which is adapted to drive the actuators. In particular, the control unit 15 comprises a memory 14 inside which the interference matrix 10 is stored which provides for each position of an actuator 8 or 9 the presence or absence of interference with respect to all possible positions. of the other actuator. More specifically, the control unit 15 is designed to determine the absolute position of the actuators through the interference matrix.

In the preferred and non-limiting embodiment illustrated in Figure 1, the articles of the tobacco industry processed by the automatic machine 1 are packets 4 of cigarettes. According to different embodiments not illustrated, the automatic machine 1 is of a different type (for example a packaging machine, a cellophane wrapping machine, or a packaging machine) and therefore the articles are cigarettes, filter pieces, packets of tobacco, cigars, etc. According to further multiple embodiments not illustrated, the algorithms used to determine the absolute position of the actuators of an automatic machine starting from an interference matrix are different and changeable on the basis of the automatic machine on which they will be applied.

Although the invention described above makes particular reference to a very precise example of embodiment, it is not to be considered limited to this example of embodiment, since all those variants, modifications or simplifications that would be evident to those skilled in the art, such as for example: the addition of further actuators, the use on another type of tobacco industry machine other than a packaging machine, the use of sets of movements generated with trajectories or algorithms other than those mentioned, etc.

The present invention has multiple advantages. First of all, it allows to determine the absolute position of each actuator that presents interference with other actuators present on board an automatic machine without the need for an expert operator. Furthermore, the determination of the absolute position of the actuators takes place automatically, in an extremely quick and economical way compared to conventional methods (no dedicated designs are necessary in order to obtain a mechanical zero for each actuator). Finally, the process according to the present invention allows to solve situations (with many hidden or interlocking or large actuators) in which the complexity or the mechanics of the system are not manageable by an operator or cause confusion in the presence of a plurality of mechanical tools (plugs), which can be lost, interchanged or damaged. Further advantages linked to the process according to the present invention relate to the possibility of calculating the interference matrices (and therefore in case of variants, adapt them to new configurations) offline, without therefore having to be connected to the automatic machine to carry out this operation. In this way, it is possible to quickly change or calculate a new interference matrix (via software) during a format (or product) change, so as to allow the user to make structural changes to the machine, without affecting the possibility of automatically making the determination of the absolute positions of the actuators on board the automatic machine. In other words, the use of interference matrices on which to apply algorithms to determine the absolute position of the actuators mounted on an automatic machine greatly facilitates and speeds up a process that would otherwise be very time-consuming (both in the design phase and in the assembly / installation).

Claims (15)

CLAIMS 1) Procedure for determining the position of the actuators (8, 9) of at least one part (2) of an automatic machine (1) for the production of articles of the tobacco industry; the procedure includes the phases of: determine an interference matrix (10) which provides, for each absolute position of an actuator (8, 9), the presence or absence of interference with respect to all possible absolute positions of the other actuators (9, 8); measuring a detected position of at least one actuator (8, 9); operate at least one actuator (8, 9) to cause the actuator (8, 9) itself to perform, starting from the detected position, a test movement having a predefined stroke or, alternatively, having a stroke lower than the predefined stroke due to of reaching an interference position; detect, during the test movement, the force or torque required to operate the actuator (8, 9); determine the achievement of an interference position when, during the test movement, the force or torque required to operate the actuator (8, 9) exceeds a threshold value; interrupt the actuation of the actuator (8, 9) when, during the test movement, an interference position is reached; and use the interference matrix (10) to uniquely determine the absolute position of at least one actuator (8, 9) on the basis of at least one result of the test displacements. 2) Method according to claim 1 wherein the actuators (8, 9) are operated sequentially. 3) Process according to claims 1 or 2, wherein the interference matrix (10) is stored in a memory (14) of a control unit (15) which is adapted to drive the actuators (8, 9). 4) Process according to any one of the preceding claims, in which: the actuators (8, 9) are electric motors; and a torque control or a current control of the electric motors verifies that the torque or current value of each electric motor does not exceed a respective limit value, in particular that the torque or current value of each electric motor falls within a predefined tolerance range. 5) Method according to any one of the preceding claims, in which following the unambiguous determination of the absolute position of an actuator (8, 9), the position detected by a position sensor coupled to the actuator (8, 9) itself is updated by means of a compensation value (Comp) so that it coincides with the absolute position (Pabs) determined. 6) Process according to any one of the preceding claims, wherein the interference matrix (10) has a dimension for each actuator (8, 9). 7) Process according to claim 6, wherein the movement of each actuator (8, 9) corresponds to the movement along a dimension of the interference matrix. 8) Method according to claim 7, wherein each actuator (8, 9) can be operated by the control unit (15) in both directions of the corresponding dimension of the interference matrix (10), in particular at least one actuator (8 , 9) makes test shifts in both directions. 9) Process according to any one of the preceding claims, in which the result of the test displacements of a first actuator (8, 9) depends on the displacements of at least one second actuator (9, 8) which has areas of interference with the first actuator . 10) Process according to claim 9, wherein, if the result of the test displacements of the first actuator (8, 9), in particular along a first dimension of the interference matrix (10), do not allow to uniquely determine its position, the second actuator (9, 8) performs a relocation movement, in particular a movement along a second dimension of the interference matrix (10), before the first actuator (8, 9) performs a further test movement. 11) Process according to claim 10, wherein the relocation displacement corresponds to a distance equal to one row of the interference matrix (10). 12) Process according to any one of the preceding claims, in which the result of the test displacements allows to identify, within the interference matrix (10), one or more search areas (18, 19) within which you will find the possible absolute positions of the actuators (8, 9). 13) Process according to claim 12, in which the at least one search area (18, 19) contracts progressively as the number of test movements performed by the actuators (8, 9) increases. 14) Process according to any one of the preceding claims, in which: the automatic machine (1) is divided into groups, each of which comprises a pair of actuators; And for each group a corresponding two-dimensional interference matrix (10) is defined. 15) Automatic machine (1) for the production of items for the tobacco industry; the automatic machine (1) includes: a plurality of actuators (8, 9), each of which is in a relative position and can assume a plurality of different positions; a plurality of detection systems, in particular position sensors coupled to the actuators, for detecting the detected position of each actuator (8, 9); a control system (3) adapted to detect, during a test movement, the force or torque necessary to actuate an actuator (8, 9) to determine whether or not an interference position has been reached; and a control unit (15) which is adapted to drive the actuators (8, 9); the automatic machine (1) is characterized by the fact that: the control unit (15) comprises a memory (14) in which an interference matrix (10) is stored which provides for each position of an actuator (8, 9) the presence or absence of interference with respect to all possible positions of the other actuators (9, 8); And the control unit (15) is designed to determine the absolute position of the actuators (8, 9) through the interference matrix (10).