EP0419833A1 - Monitoring device - Google Patents

Abstract

What is described is a device for the contactless monitoring of a region (14) adjacent to a service robot (12) of a ring spinning machine (10), said device comprising an electroacoustic transducer (18). The transmitted sound signal supplied by the transducer (18) is divided into a measurement sound signal (SSM) and a reference sound signal (SSR). An electronic control unit (16) supplies a fault signal when no sound signal has been received by the expiry of a reference running time. On the other hand, if a sound signal is received before the expiry of the reference running time, the control unit (16) supplies a recognition signal. <IMAGE>

Description

The invention relates to a device for contactless monitoring of an area adjacent to a movable machine part, in particular a movable operating robot of a spinning machine, with at least one electroacoustic transducer arranged on the movable machine part and connected to an electronic control unit for emitting a transmitted sound signal and for receiving an on one in the surveillance area existing object or a person present there reflected reception sound signal.

Personal and collision protection are becoming increasingly important as part of the automation of processes, for example using movable operating robots. It must be ensured that the respective operators are not endangered by the automatically controlled moving machine parts, robots, vehicles and the like. On the other hand, care must be taken to ensure that movable machine units, such as robots, which can be controlled independently of one another do not collide.

There are a variety of non-contact sensing sensors, such as capacitive, magnetic, electromagnetic, and optical detectors. Capacitive, magnetic and electromagnetic sensors generally have the decisive disadvantage that the measurement result depends on the respective object material. Furthermore, their range is relatively short. Acoustic sensors are also used to detect the presence of certain target objects, which meet the requirements with regard to a measurement result that is as independent as possible of the object material become right (see, for example, the special print "Non-contact distance measurement" in the trade magazine "Electronics", 32nd year, No. 26/1983, Franzis-Verlag, Munich). However, the known acoustic monitoring systems have the disadvantage that dangerous collisions can no longer be reliably ruled out, particularly in the case of defects occurring in the field of sensors.

The invention has for its object to provide a device for contactless monitoring of an adjacent to a movable Mateil area of the type mentioned, di not only ensures reliable monitoring of the area in question with a simple structure, but at the same time ensures that the required people and Collision protection is always fully available even if errors occur that interfere with normal operation, particularly in the area of sensors.

The object is achieved according to the invention in that means are provided for dividing the transmitted sound signal into a sound measurement signal directed into the monitoring area and a sound reference signal which is directed to a reference reflector having a predeterminable distance from the electroacoustic transducer and a reference transit time determined by this distance between delivery and receipt, and that the electronic control unit on the one hand delivers an error signal signaling an error in the monitoring device if no sound signal was received by the end of the reference term, and on the other hand one representative of the presence of an object or a person in the monitoring area Detection signal emits as soon as a sound signal is received before this reference period.

Due to this training errors and defects are particularly Detected immediately and reliably, particularly in the field of sensors, so that, if necessary, a corresponding intervention in the drive control of the relevant movable machine part, for example the operating robot which can be moved along a spinning machine, can take place. Such an intervention can take place automatically when the error signal supplied by the electronic control unit occurs.

If the monitoring device works faultlessly and there is no operator or no disturbing object in the monitoring area, after the transmission of the transmission sound signal, after a time which corresponds to the reference running time, a sound signal is received, which is the sound reference signal reflected at the reference reflector. In this case, the monitoring device remains passive since neither an object in the monitoring area nor an error in the device was detected. In this case, there is no reason to intervene in the drive control, for example the operating robot.

If, on the other hand, a sound signal is received before the reference runtime has elapsed after the emission of a respective transmission sound signal, the electronic control unit of the monitoring device recognizes that either a disturbing object is present in the endangered monitoring area or that an operator is located in this monitoring area.

Finally, if the sound signal received first after the transmission or release of the transmitted sound signal occurs after the predefinable reference running time has elapsed, the electronic control unit recognizes therein an error or defect, particularly in the sensor system of the device. Possible sources of error are, for example, that as a result of an error the transmitter, no sound pulses were emitted, despite the fact that no transmitted reference sound was received, especially due to contamination of the transducers, the received signals are too weak or a new adjustment of the sensor arrangement is necessary.

The personal and collision protection according to the invention can be used, for example, on machines such as robots, in particular spinning machines, moving machines or machine parts, vehicles and transport systems, in particular in spinning plants. A preferred area of application is the operating robots of spinning machines. The solution according to the invention in particular also ensures reliable collision protection when using two or more operating robots. In the latter case, each of the operating robots is expediently equipped with a monitoring device according to the invention.

An ultrasonic transducer is preferably provided as the electro-acoustic transducer, so that the device is particularly insensitive to the normally occurring industrial noise.

The electroacoustic transducer preferably forms a sound transmitter and sound receiver at the same time. By appropriately designing the electronic control unit, the electroacoustic transducer is operated alternately as a transmitter and receiver in this case. The structure of the entire arrangement can be kept particularly simple in this case.

The means for splitting the transmitted sound signal comprise at least one passive sound deflection element, which can be a reflector, for example, which is arranged in this way is that part of the transmitted sound component is passed to the monitoring area, while the other sound component is redirected to the differential reflector.

According to a particularly advantageous embodiment variant, it is provided that the distance between the electroacoustic transducer and the reference reflector is adjustable and, for this purpose, the reference reflector is preferably adjustable. Since the distance that can still be measured, for example of an object present in the monitoring area, depends on the distance of the reference reflector from the transducer, the distance that can still be measured of the object can also be varied with this distance.

For example, the floor or surface on which the machine in question is installed can serve as a reference reflector. A reference reflector can also expediently be arranged on a fixed part of the machine in question, for example on a spinning machine along which an operating robot travels back and forth. In any case, it should be noted that the distance between the electroacoustic transducer and the reference reflector remains the same regardless of the respective position of the movable machine part or operating robot.

According to another expedient embodiment variant, the reference reflector is arranged on the movable machine part, for example on a movable operating robot of a spinning machine.

In the case of a machine part which can be moved in at least two different directions, in particular an operating robot which can be moved, for example, in two opposite directions, at least one electroacoustic transducer is preferably provided for each direction movable movable machine part or operating robot in a respective direction of travel, only the electroacoustic transducer assigned to this direction can be controlled by the electronic control unit. This ensures that the signals received are always clear and that the area that is endangered as a result of the machine part being led into this area is monitored in any case.

According to a practically preferred embodiment variant, it is provided that the drive of the movable machine part, for example the operating robot in question, can be controlled in particular by the electronic control unit when a detection signal occurs in such a way that the movement of the movable machine part is interrupted or reversed at least temporarily. The respective danger is therefore automatically eliminated without any action on the part of an operator. For example, in the case of an operating robot which can be moved along the spinning positions of a spinning machine, the direction of movement can be reversed when a risk of collision occurs. A renewed reversal of the direction of movement can then take place at certain, predetermined path locations. On the other hand, it is also conceivable to interrupt the movement of the operating robot, for example, and then move this operating robot again in the same direction as soon as the area to be monitored is released.

The occurrence of the error signal can preferably be signaled by the electronic control unit so that it can be recognized by a respective operator. It is also expediently provided that, in the event of a detected fault, the movable machine part or the operating robot is automatically shut down for safety reasons.

• Figur 1 eine schematische Seitenansicht einer Ringspinnma­schine, der ein entlang der Spinnstellen verfahrba­rer, mit einer akustischen Überwachungsvorrichtung ausgestatteter Bedienroboter zugeordnet ist,
• Figur 2 eine schematische Darstellung der elektronischen Steuereinheit der Überwachungsvorrichtung sowie eine schematische Darstellung des Strahlverlaufs im Überwachungsbereich,
• Figur 3 ein Laufzeitdiagramm der Schallpulse bei einem weiter vom Bedienroboter entfernten Gegenstand, und
• Figur 4 ein Laufzeitdiagramm der Schallpulse bei einem dem Bedienroboter näher gelegenen Gegenstand.

The invention is explained below using an exemplary embodiment with reference to the drawing; in this shows:

• FIG. 1 shows a schematic side view of a ring spinning machine, to which an operating robot that is movable along the spinning positions and is equipped with an acoustic monitoring device is assigned.
• FIG. 2 shows a schematic illustration of the electronic control unit of the monitoring device and a schematic illustration of the beam path in the monitoring area,
• 3 shows a time-of-flight diagram of the sound pulses in the case of an object further away from the operating robot, and
• FIG. 4 shows a transit time diagram of the sound pulses in the case of an object closer to the operating robot.

1 shows a schematic illustration of one side of a ring spinning machine 10 with a plurality of spinning stations 34 which are arranged between a head part 36 and a foot part 38 of the spinning machine. An equal number of spinning positions are provided on the opposite machine side, which cannot be seen.

At each of the spinning stations 34, roving 42 coming from a roving bobbin 40 is drawn in a drafting device 44 and the drawn yarn is wound onto a spinning sleeve 48 by means of a ring traveler 46 to form a package 50.

The ring spinning machine 10 is assigned an operating robot 12 which runs along an upper guide rail 52 and a lower guide and positioning rail 54 is guided. This operating robot 12, which represents a movable machine part, can be moved in the direction of the double arrow 56 along the spinning stations 34. The operating robot 12 can have an automatic attachment and winding machine (not shown) and further units (also not shown) for operating the respective spinning stations.

The operating robot 12, which can be moved along the guide rails 52, 54, is equipped with a device for contactless monitoring of the areas 14 adjoining its two sides.

This monitoring device has on each of the two opposite sides of the operating robot 12 an electroacoustic transducer 18 for emitting a transmitted sound signal S _S and for receiving a received sound signal S _E (see also FIG. 2). These two electroacoustic transducers are connected to an electronic control unit 16. This electronic control unit can be part of the control unit assigned to the operating robot 12 and in particular also serving to drive control this robot.

As can be seen in particular from Figure 2, each electroacoustic transducer 18 is assigned a passive sound deflection element 22, which in the present case is a simple flat reflector which is pivoted by 45 ° with respect to the vertical, so that the horizontally incident sound signal is perpendicular to the bottom Ring spinning machine-carrying floor is reflected, which, as will be explained in more detail below, serves as a reference reflector 24.

The passive sound deflection element 22 serves to divide the Transmitted sound signal S _S emitted by the relevant electroacoustic transducer 18 into a sound measurement signal S _SM directed into the monitoring area 14 and a sound reference signal S _SR . A corresponding division accordingly also takes place for the received sound signal S _E received by the electroacoustic transducer 18.

The sound measurement signal S _{SM used} to monitor the monitoring room 14 thus runs from the electroacoustic transducer 18 into the monitoring room 14 and, in the case of an object 20 or 20 ′ or a person present in this monitoring room 14, as a result of the reflection taking place back to the transducer 18.

By contrast, the noise reference signal S _SR-forming portion is the coming from the transducer 18 transmit sound signal S _S is reflected on the passive Schallumlenkelement 22 down to the bottom or the reference reflector 24, then this noise reference signal S _SR in imgekehrter direction again via the passive Schallumlenkelement 22 back to the transducer 18 arrives where it forms part of the received sound signal S _E received by the converter 18.

The floor or reference reflector 24 is measured along the simple beam path of the sound reference signal S _{SR at} a predetermined distance a from the electroacoustic transducer 18.

The distance X _m of the object 20 present in the monitoring space 14 is greater than the above-defined distance a of the floor or reference reflector 24 from the transducer 18. In contrast, the object 20 'has a smaller distance X' _{m from} the transducer 18 than the distance a .

According to FIG. 2, the electronic control unit 16 comprises a microprocessor 26 with an input 60, for example, connected to an input unit (not shown) and an output 62, via which the microprocessor detects an error signal U _F in the case of a faulty monitoring device and, upon detection of an object 20 'present in the monitoring area 14' or a person present there, a detection signal U _E delivers.

While a signal generator 58 (see FIG. 1) can be controlled by means of the error signal U _F, for example, a respective detection signal U _{E can be used} for a corresponding intervention in the drive control of the operating robot 12.

In the present exemplary embodiment, the electroacoustic transducer 18 delivering ultrasound pulses simultaneously forms a sound transmitter and a sound receiver. The converter 18 is alternatively controlled by the electronic control unit 16 as a transmitter or receiver. For this purpose, the electronic control unit 16 comprises transmission electronics 28 connected to the microprocessor 26 and also receiver electronics 30 also connected to the microprocessor, which can have a reception amplifier, for example. Furthermore, the microprocessor 26 of the electronic control unit 16 is assigned a counter 32, by means of which the respective transit times of the sound signals received can be determined.

The two electroacoustic transducers 18 provided on opposite sides of the operating robot 12 are controlled individually as a function of the respective direction of travel of the robot 12. The electronic control unit 16 of the monitoring device or of the operating robot 12 controls the electroacoustic transducer 18, which is connected to the operating robot ter 12 adjacent monitoring area provides ultrasonic pulses into which the operating robot is moved. The other converter is deactivated.

FIG. 3 shows a time-of-flight diagram for the ultrasound pulses as they result from an object 20 present in the monitoring area 14, which is further away from the electroacoustic transducer 18 than the distance a of the floor or reference reflector 24 from this transducer 18 defined above corresponds.

On the other hand, a time-of-flight diagram of the ultrasound pulses is shown in FIG. 4, which shows their course in the case of an object 20 'present in the monitoring area 14, which is closer to the electroacoustic transducer 18 than this corresponds to the distance a defined above. While the time is plotted on the abscissa, the ordinate indicates the respective object distance. Accordingly, it can be seen that the respective ultrasound pulse runs from the electroacoustic transducer 18 to the target object, ie to the object 20 or 20 ', is reflected there at the time t _{m / 2} or t' _{m / 2} and the transducer 18 again at time t _m or t ′ _m reached (solid lines). This transit time t _m or t ' _{m of} the sound measurement signal S _SM (see FIG. 2) is directly proportional to the object distance X _m or X' _m . The relationship applies
X _m = 1/2 ct _m , or
X ′ _m = 1/2 ct ′ _m .

The ultrasound pulse of the sound reference signal S _SR runs from the electro-acoustic transducer 18 to the passive sound deflection element 22, is reflected there to the floor or reference reflector 24 and there again at the time T _{R / 2} back to the passive sound deflection element 22 and there again reflected to the transducer 18, where it follows a reference term T _R arrives.

The monitoring device according to the invention works as follows:

If the monitoring device is working correctly and there is an object 20 in the monitoring room 14 that is relatively far away from the electroacoustic transducer 18, the transducer 18 first receives the sound reference signal S _SR reflected on the floor or reference reflector 24 (see FIGS. 2 and 3). The sound measurement signal S _SM reflected at the more distant object 20 occurs at a later time t _m . By receiving a signal, namely the sound reference signal S _S R, until the reference time T _{R has} elapsed, the electronic control unit 16 recognizes that the monitoring device is working correctly. Since the sound measurement signal S _SM reflected on the object 20 is received at a later time t _m > T _R , this signal is no longer taken into account by the electronic control unit 16, so that a detection signal U _{E is} not emitted. On the other hand, an error signal U _{F is} also not output because the sound reference signal S _SR occurred at the predetermined time, ie after the reference running time T _R. In the case shown in FIG. 3, the distance X _m is correspondingly greater than the distance a.

If, however, the article 20 'closer to the electro-acoustic transducer 18, that is, the distance a is greater than the distance X as' _m, then a variation in time of the ultrasonic pulses figure obtained according to 4. Accordingly, the' reflected from the object 20 Schallmeßsignal S _SM to a Receive time t ' _m before the expiry of the predetermined reference time T _R. Nachdm t ' _m <T _R , the electronic control unit 16 supplies a detection signal U _E , which is for the presence of the object 20' or one of the same distance distant person in the surveillance area 14 is representative.

If there is no object 20 or 20 'in the monitoring area 14 when the monitoring device is working correctly, then the same conditions result as in the case of an object 20 which is further away from the transducer 18 and thus not detected (see FIG. 3).

In particular, in the event of an error or defect in the sensor system, the sound reference signal SSR is received only after the predetermined reference time T _R , which has been stored, for example, or not at all. This is evaluated by the electronic control unit 16 as an error in the monitoring device. Consequently, the electronic control unit 16 supplies the error signal U _F , via which the signal transmitter 58 (see FIG. 1) in particular can be controlled. At the same time, the operator robot 12 will be shut down for safety reasons.

On the other hand, if the detection signal U _{E occurs} , which is representative of the presence of an object or a person in the monitoring area, it is not absolutely necessary to stop the operating robot 12. Rather, it can be expedient to control the drive of the operating robot 12 in the sense of reversing the direction of travel.

Claims (10)

1. Device for contactless monitoring of an area (14) adjacent to a movable machine part (12), such as in particular a movable operating robot of a spinning machine (10), with at least one electroacoustic transducer (18) arranged on the movable machine part and connected to an electronic control unit (16) ) for emitting a transmitted sound signal (S _S ) and for receiving a received sound signal (S _E ) reflected on an object (20) present in the monitoring area (14) or a person present there,
characterized by
that means (22) are provided for dividing the transmitted sound signal (S _S ) into a sound measurement signal (S _SM ) directed into the monitoring area (14) and a sound reference signal (S _SR ) which is at a predeterminable distance (a) from the electroacoustic Transducer (18) having reference reflector (24) is directed and has a reference transit time (T _R ) between delivery and reception determined by this distance (a), and that the electronic control unit (16) on the one hand each has an error signal signaling an error in the monitoring device ( U _F ) delivers if no sound signal has been received by the end of the reference time (T _R ) and, on the other hand, emits a detection signal (U _E ) representative of the presence of an object (20) or a person in the monitoring area (14) as soon as a sound signal is received before the expiry of this reference term (T _R ). 2. Device according to claim 1,
characterized,
that an ultrasonic transducer (18) is provided as the electroacoustic transducer. 3. Device according to claim 1 or 2,
characterized by
that the electroacoustic transducer (18) simultaneously forms a sound transmitter and sound receiver. 4. Device according to one of the preceding claims,
characterized by
that the means (22) for dividing the transmitted sound signal (S _S ) comprise at least one passive sound deflection element. 5. Device according to one of the preceding claims,
characterized by
that the distance (a) between the electroacoustic transducer (18) and the reference reflector (24) is adjustable and for this purpose the reference reflector (24) is preferably adjustable. 6. Device according to one of the preceding claims,
characterized by
that the reference reflector (24) is arranged on a fixed part of the machine in question, in particular a ring spinning machine, or is formed by the floor carrying the machine or is arranged thereon. 7. Device according to one of claims 1 to 5,
characterized by
that the reference reflector (24) on the movable machine part (12) and in particular on a movable operator robot is arranged. 8. Device according to one of the preceding claims,
characterized by
that at least one electroacoustic transducer (18) is provided for each direction in a machine part (12) that can be moved in at least two different directions, in particular an operating robot, and that when the movable or movable machine part (12) moves in a respective direction of travel in each case only the electroacoustic transducer (18) assigned to this direction can be controlled by the electronic control unit (16). 9. Device according to one of the preceding claims,
characterized by
that the drive of the movable machine part (12) when the detection signal (U _E ) occurs can be controlled in particular by the electronic control unit (16) such that the movement of the movable machine part (12) is interrupted or reversed at least temporarily. 10. Device according to one of the preceding claims,
characterized by
that the occurrence of the error signal (U _F ) can be signaled by the electronic control unit (16) so that it can be recognized by a respective operator.

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