DE102011121839A1 - Method for movement controlling of machine e.g. packaging machine, involves controlling operation of drive device based on moment of inertia of driven element, so as to reduce tracking error relative to desired movement path - Google Patents

Abstract

The method involves driving a driven element (12) along predetermined path with predetermined torque curve by drive device (2) such as servomotor. The drive device is controlled so that predetermined path is equal to predetermined desired movement path. The cyclic characteristic of the driven element is detected. The moment of inertia of driven element is determined using size and acceleration reference value of driven element. The operation of the drive device is controlled based on moment of inertia of driven element, so as to reduce tracking error relative to desired movement path. Independent claims are included for the following: (1) machine; and (2) drive device.

Description

The present invention relates to a method of controlling a machine and a correspondingly controlled machine.

In the prior art different machines are known in which accelerated movements occur. The term acceleration is understood to mean both the positive acceleration and the negative acceleration, d. H. a delay.

Due to this acceleration of drives can lead to tracking errors in such machines, d. H. to errors between a target position of a driven body and an actual actual position. Corresponding control devices often can not respond adequately to the variable loads.

The present invention will be described with reference to a packaging machine or a printing machine, but it should be noted that the invention can also be applied to other machines, such as but not limited to machine tools or handling axes. In general, the invention is preferably applicable to such machines in which strong acceleration processes so acceleration and / or braking operations occur.

The object of the present invention is therefore to provide a method and a device which, in particular, also facilitate the control of processes which have variable loads or non-linear kinematics. In particular, a following error is to be reduced in this way.

These objects are achieved by the subject-matter of the independent claims. Advantageous embodiments and further developments are the subject of the dependent claims.

In a method according to the invention for controlling a machine, a first drive device drives a first body to be driven along a first predetermined movement path with a predetermined first drive torque curve. In this case, the first drive device is controlled such that the first (actual) movement path essentially corresponds to a predetermined desired movement path. Furthermore, the body to be driven is accelerated at least once during its movements along the movement path.

According to the invention, a first physical variable, which is characteristic of the movement of the driven body, is repeatedly recorded (eg determined or measured by the control) and by means of this first characteristic variable and at least one setpoint value which is suitable for a Characterized acceleration of the driven body, a characteristic of the moment of inertia of the driven body is determined result value. Furthermore, the first drive device is at least temporarily controlled taking into account this result value so as to reduce a following error (in particular of the actual movement path) relative to the desired movement path.

Advantageously, the movement of the driven body is a rotation. However, the invention is also applicable to other types of movements in which, for example, a determination of the inertial mass (i.e., the equivalent of the moment of inertia) could be made.

Advantageously, the (positive or negative) acceleration is effected by the drive device or by a corresponding control of the drive device. Advantageously, the driven body is at least once positively accelerated during its movement and at least once accelerated negatively.

Advantageously, at least one acceleration action causes a final velocity of the driven body (ie, the velocity reached after the acceleration process) to increase by at least 10%, preferably at least 20% and most preferably at least 30% from the initial velocity of the driven body (ie, velocity the acceleration process).

Preferably, a constant acceleration of the driven body takes place. However, it would also be conceivable that the acceleration changes with time.

As is known, the moment of inertia describes with which angular acceleration a body responds to an acting torque. In general, this moment of inertia depends on the shape and mass distribution of the body as well as on the axis of rotation and plays the same role in the rotational movement as the mass in the linear movement. In the context of the invention, however, it is proposed to determine the moment of inertia, which actually acts on the drive or a motor shaft driven by the drive, and preferably also for the control of the drive. Below the moment of inertia is hereafter understood both the moment of inertia in the case of a rotational movement and the moment of inertia or the inertial mass in other movements. By cyclical is meant, in particular, that the determination of the moment of inertia (at least at times, in particular starting from certain acceleration absolute values) takes place continuously, ie in particular repeatedly. Advantageously, the determination of the moment of inertia takes place with equal intervals.

Preferably, this variable inertia torque determined in this way is used to control the drive so that, for example, the control devices, filters or also feedforward processes operate in consideration of this determined moment of inertia.

Furthermore, this so-determined moment of inertia is preferably used for the future control of the first drive device. However, it would also be possible for the determined moment of inertia to be used directly or online for adapting the regulation of the drive device. Thus, for example, within the scope of the regulation, a desired value of the movement of the driven body can be specified, and a regulating device can regulate the drive device in a manner known per se. The determined moment of inertia is (adaptively) taken into account in this regulation in order to adapt the control of the drive device.

Advantageously, the first physical quantity characteristic of the movement of the driven body is an actual value, i. H. the value that z. For a momentary, d. H. torque applied at the time of measurement, or characteristic of a force in the case of another movement.

Furthermore, the physical variable is advantageously an acceleration value which is characteristic for an acceleration and in particular an actual acceleration of the driven body. However, this actual acceleration may also be determined via an actual position value of the driven body, and the actual acceleration value may be determined from this actual position value (by (twice) differentiation according to time).

In an advantageous method, an acceleration value is determined and the determination of the result value takes place only if the acceleration value is greater in magnitude than a predetermined limit value. Advantageously, the determination of the moment of inertia in each acceleration phase, d. H. both in the acceleration and in the deceleration phase.

However, it would also be possible that the physical size z. B. a torque is determined when the absolute value of the acceleration is above a predetermined limit. In those phases in which the acceleration is below the said limit value, an average value of the physical quantities can be formed, preferably a moving average, and the determined value can be tracked.

The amount of acceleration is significant, and a minimum value is assumed, otherwise the accuracy in the calculation of the moment of inertia will deteriorate because a signal-to-noise ratio becomes insufficient.

It would be possible to make the said limit of the adaptation depending, but it would also be possible to specify the respective acceleration limit absolute.

In a further advantageous method, the setpoint is an acceleration setpoint. Thus, the moment of inertia is preferably determined from said acceleration target value and the above-mentioned acceleration value. In general, the moment of inertia applies to: J_X = M_X / a_X, where M_X is the torque, J_X the moment of inertia and a_X the angular acceleration. In the context of the invention, the torque is preferably detected and the angular velocity represents the above-mentioned desired value. However, it would also be conceivable that a physical quantity is detected, which in turn is characteristic of the torque.

In the present case, the acceleration value used is a normalized value which is related to a continuous torque of the drive.

In a further advantageous method, the acceleration full value is determined from a position setpoint. Thus, it is conceivable that the position setpoint value is predetermined, for example, by an external control, and from this the acceleration setpoint value is determined by a twofold differentiation according to the time.

In a further advantageous method, the characteristic result value is determined at least once in the presence of a positive acceleration of the driven body and once in the presence of a negative acceleration of the driven body. In this preferred variant, an acceleration process and a braking process (negative acceleration) are considered and in each case a reduced value J_Red is considered.

Friction effects inhibit this acceleration in a positive acceleration, and friction (negative acceleration) causes additional delay in friction. In this way, it is possible to consider the acceleration and braking separately and to eliminate, for example by averaging the friction component. In other words, by determining the moment of inertia both during a (positive) acceleration and during a (negative) acceleration ie deceleration of the driven body, the friction can be determined.

Preferably, the moment of inertia thus determined, particularly preferably online, is used and in this way an adaptive parameter adaptation of the respective following values is carried out. For example, an acceleration precontrol can be undertaken since the acceleration is dependent on inertia. Furthermore, in this way an acceleration observer can be made available in the case of sensorless vibration damping. In a further preferred method, the determination of the moment of inertia is done without encoder. Thus, no observation of the rotational position or the position of other drives is made beforehand. In particular, a following error for servo drives with variable load can be optimized or reduced by the procedure described here. In addition, the system described here is also helpful for systems with nonlinear kinematics to improve the dynamics.

Pre-control of the first drive device preferably takes place, and the determined result value is taken into account for this precontrol. Preferably, no direct determination of occurring torques or forces takes place. Thus, it would be conceivable that the drive device is controlled in a conventional manner by a control device and the determined inertias are considered as specifications for this control device or switched to the outputs of the control device. Also, the determined inertias in the context of additive variables could be taken into account in the control of the drive device.

The present invention is further directed to a machine having a first drive means which drives a first driven body to move along a predetermined travel path. The first drive means accelerates the movement of the driven body during its movement at least once positively or negatively. Furthermore, a detection device is provided which cyclically detects at least a first physical variable which is characteristic for the movement of the driven body and thereby outputs a detection value or measured value which is characteristic of this characteristic variable.

According to the invention, the machine has a determination or process preparation device which, on the basis of the characteristic variable (in particular detected by the detection device) and at least one desired value which is characteristic for an acceleration of the driven body, determines a result value characteristic of an inertia moment of the driven body and a control device which controls the first drive device taking into account this result value.

The detection device may be, for example, a measuring device z. B. about a sensor device act, which determines the physical quantity such as a torque, but it would also be possible that the detection of the physical quantity by means of the drive control is done, for example by means of a rotary encoder.

It would be possible that a continuous torque is detected or used as the basis and additionally a torque actual value based on this continuous torque is determined, d. H. This torque actual value is multiplied by this continuous torque (in Nm). Preferably, therefore, the detected physical quantity and the desired value are mathematically linked to one another.

In a preferred embodiment, the first drive device is a synchronous motor and / or a servomotor. Such synchronous motors or servomotors are suitable for the procedure proposed here in a special way, since a high accuracy can be achieved here and in other drives, the moment is not so well known.

Particularly preferably, the drive device is a rotary drive. However, a drive would also be conceivable which moves a body to be driven along another path, for example, of a linear path or also of a curved path.

The control device is preferably a regulating device which regulates the drive device or its operation. This control device may in turn have different components such as position controller, speed controller, I-controller and the like. These respective components can also be connected in series, so that the output of one of these components is fed to another component. A consideration of the determined inertia can also be said between the said Components are made, for. B. by adding an additive term to certain controller outputs.

Further advantages and embodiments will become apparent from the attached drawings:

It shows:

1 a rough schematic representation of an application example of the present invention.

1 shows a rough schematic representation of an application example of the present invention. There is a machine 1 shown, which is a first electric motor drive 2 comprising a first driven body 12 here for rotation with respect to a rotation axis D drives. This rotation of the driven body 12 is thus the movement along the given path of movement is illustrated by the double arrow. This will be the movement of the driven body 12 accelerated at least once positively or negatively, ie accelerated or delayed.

The reference number 32 refers to a detection device, such as a sensor or a rotary encoder, which has a physical size necessary for the movement of the driven body 12 is characteristic, recorded. For example, this may be a position or rotational position value of this driven body 12 act. The detection device 32 detects this actual position value cyclically, ie in particular repeatedly.

Furthermore, the detection device gives this detected value or a value derived therefrom to one in its entirety 20 characterized control device. This control device 20 serves here to control the first drive means 2 , A detection device, such as a processor unit 22 , based on the characteristic quantity or the detection value, calculates a result value characteristic for an inertia moment of the driven body. The control device 20 then controls the drive device 2 taking into account this result value.

Due to the acceleration or deceleration of the driven body, variable load inertia results, which are adapted to the filters described here in the pilot control method.

The device also has a second drive 4 on top of a second powered body 14 drives. Again, a rotational movement with respect to a second axis of rotation D2 is provided. Furthermore, here is a detection device 34 provided for the movement of this second driven body 14 characteristic size recorded cyclically. By the control device 20 can also use the two drive devices 2 and 4 be matched to each other and, for example, by the invention also deviations of the respective rotational movements between the two drive means 2 and 4 be reduced. It would also be possible for the respective moments of inertia to be calculated and, for example, to be advanced in advance depending on a position value, so that a control on the basis of these previously determined moments of inertia is possible. The determined inertia can then be used online as mentioned above and used, for example, for a parameter adaptation. Thus, for example, for speed or position values which are output by or supplied to a control device, the determined inertia can additionally be taken into account in order to adapt the controller data in this way.

Thus, for example, a self-learning algorithm can be made available, wherein, for example, in the first cycle of motion, the moments of inertia are calculated on the basis of the determined data and are used as a basis for another later cycle. In this further cycle, again, the moments of inertia can be determined and used as a basis. In this way, an increasing accuracy in the control of the respective driven body 12 . 14 possible.

The reference number 24 indicates a memory device in which, for example, the detected values or also the determined moments of inertia can be stored. In this case, it can be stored, for example, how the determined moments of inertia behave in dependence on predetermined occurring accelerations or decelerations of the driven bodies. The values for the moments of inertia can be recorded and / or stored together with the actual position values or other determined or predetermined values. In this case, an averaging over earlier recorded values can be carried out, or, for example, also a moving averaging.

The present invention is particularly suitable for a printing press, which is preferably also about the movements of multiple axes or waves as closely as possible to each other. Advantageously, the in 1 Therefore, the machine shown also on an application unit, which applies a printing medium on a body to be printed. The in 1 shown control device 20 is, as known from the prior art, preferably also a desired position value for the motion control of the drive means 2 and 4 or the driven body 12 and 14 specified.

LIST OF REFERENCE NUMBERS

1

machine

2

first drive device

4

second drive device

12

first powered body

14

second powered body

20

Control device or regulating device

22

processor unit

24

memory device

32

detector

34

detector

D1, D2

rotational axes

Claims (11)

Method for controlling a machine ( 1 ), wherein a first drive device ( 2 ) a first driven body ( 12 ) drives along a first predetermined movement path with a predetermined first drive torque curve, wherein the first drive device ( 2 ) is controlled such that the first movement path substantially corresponds to a predetermined desired movement path and wherein the driven body ( 12 ) is accelerated at least once during its movement, characterized in that at least a first physical quantity which is characteristic of the movement of the driven body is detected cyclically and by means of this first characteristic quantity and at least one desired value (a_set) which is responsible for an acceleration of the driven body, one for a moment of inertia of the driven body ( 12 ) characteristic result value is determined and the first drive device ( 2 ) is at least temporarily controlled in consideration of this result value so as to reduce a following error with respect to the target movement path. Method according to Claim 1, characterized in that an acceleration value (a_act) or a value characteristic of an acceleration value is determined as the first physical variable. Method according to at least one of the preceding claims, characterized in that the determination of the result value only takes place when the acceleration value is greater in magnitude than a predetermined limit value. A method according to claim 1, characterized in that the desired value is an acceleration setpoint (a_soll). A method according to claim 4, characterized in that the acceleration setpoint is determined from a position setpoint. Method according to at least one of the preceding claims, characterized in that the characteristic result value is obtained at least once in the presence of a positive acceleration of the driven body ( 12 ) and once in the presence of a negative acceleration of the driven body ( 12 ) is determined. A method according to claim 6, characterized in that on the basis of a first characteristic result value, which was determined in the presence of a positive acceleration of the driven body and based on a second characteristic result value, which was determined in the presence of a negative acceleration of the driven body, averaging takes place , Method according to at least one of the preceding claims, characterized in that a pilot control of the first drive means takes place and the result value is taken into account for this feedforward control. Machine ( 1 ) with a first drive device ( 2 ), which has a first driven body ( 12 ) drives to a movement along a predetermined path of movement, wherein the first drive means ( 2 ) the movement of the driven body ( 12 ) is accelerated positively or negatively at least once during its movement, with a detection device ( 32 ), which at least a first physical quantity, which for the movement of the first driven body ( 12 ) is characteristic, cyclically detected, and outputs a detection value that is characteristic of this characteristic physical quantity, characterized in that the machine ( 1 ) a determination device ( 22 ), which, on the basis of the detection device ( 32 ) and at least one desired value (a_soll) which is responsible for an acceleration of the driven body ( 12 ), one for a moment of inertia of the driven body ( 12 ) characteristic result value and a control device ( 20 ), which the first drive means ( 2 ), taking into account this result value. Machine according to claim 9, characterized in that the first drive means ( 2 ) is a synchronous motor and / or a servomotor. Apparatus according to claim 9, characterized in that the drive device ( 2 ) is a rotary drive.

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