DE102017101905B4 - Monitoring device - Google Patents

Abstract

Monitoring device (30) for monitoring a movable machine part (12), which is used in particular for processing or handling a workpiece (14), the movable machine part (12) being controlled by a process controller (28), the monitoring device (30) at least one Contactless sensor system (18, 20, 32) for detecting the position of the movable machine part (12) and for detecting the position of an object (24), for example a person or an obstacle, in the vicinity of the movable machine part (12), the Sensor system (18, 20, 32) is designed to differentiate between several different positions of the movable machine part (12) and several different positions of the object (24), the sensor system (18, 20, 32) having several single-photon avalanche Diode (SPAD) distance sensors (18, 20), the monitoring device (30) being designed based on the detected by means of the sensor system (18, 20, 32) Positions of the movable machine part (12) and the object (24) to recognize a dangerous situation and, if the dangerous situation exists, to send a braking and / or switch-off and / or evasive signal to a safety input (34) of the movable machine part (12), and the Monitoring device (30) is independent of the process control (28), characterized in that the monitoring device (30) is designed to determine the position of the movable machine part (12) exclusively by means of the sensor system (18, 20, 32).

Description

The present invention relates to a monitoring device for monitoring a movable machine part, the movable machine part being used in particular for machining or handling a workpiece.

Monitoring devices of various types are used, for example, where people are in the vicinity of movable machine parts, for example robots. There is a risk that a person will be injured by the moving robot.

When humans and robots work together, a strict separation between humans and robots should be avoided as far as possible in order to enable collaboration between the two. Conventional monitoring devices or safety sensors already allow humans and robots to work together, the safety sensor, for example, recording movement data of people who are in the vicinity of the robot. The robot itself transmits its own position data to a process controller. The process control also receives the person's position and movement data and then carries out a safety assessment. If a dangerous situation is recognized during the safety assessment, the process controller can generate safety-relevant control signals in order to avoid a collision between robot and human, for example.

The safety sensors are often large in their installation space, expensive, and complex and complex in their integration. In order to enable a person to be recorded, a great deal of effort and space is required.

The period of time that is required until the position data of the robot are available in the process control is relatively long and, for certain applications, not short enough to avoid a collision between humans and the robot. This period of time would therefore require too large a “buffer zone” between humans and robots, which is associated with restrictions for the cooperation between humans and robots. In addition, the coupling of a safety sensor to the process control (e.g. a common industrial control, such as a programmable logic controller), as mentioned above, is complex and expensive. The high effort and the high costs are due to the fact that the sensor signals usually have to be combined and a gateway between the safety sensor and the process control is usually necessary. Because of this long signal chain, the signal transit times between the safety sensor and the process control are relatively long. Finally, the process controls usually used for the time-critical task of preventing a collision between humans and robots are often too slow.

In addition, latency times that arise due to the sensor response time, the reaction time of the robot or the processing time of a controller must be compensated for by greater safety distances between the person and the hazardous point. The slower the safety system, the greater the safety distance that a human has to keep from the robot. However, larger safety distances impair the cooperation between humans and robots.

A method for monitoring a danger area on a movable machine part with a protection area, a tool being attached to the machine part, is disclosed in the subsequently published patent application DE 10 2015 112 656 A1 famous. In this case, at least one optoelectronic distance sensor is provided for monitoring the danger area, the distance sensor being arranged on the movable machine part.

Furthermore is from the utility model DE 20 2013 104 860 U1 a working device with an industrial robot is known to which a tool is attached. The working device corresponds to the preamble of claim 1 and comprises a controller and a detection device connected to the controller, the detection device comprising a sensor device for distance detection which detects a distance between the industrial robot and a worker.

Finally reveals the EP 3 091 272 A1 the use of SPAD (Single Photon Avalanche Diode) sensors.

The object on which the invention is based is to specify a monitoring device for monitoring a movable machine part, which is of compact design and enables dangerous situations to be recognized quickly enough with little effort.

According to the invention, this object is achieved by a monitoring device having the features of claim 1.

The monitoring device comprises at least one contactless sensor system for detecting the position of the movable machine part and for detecting the position of an object, for example a person or an obstacle, the object being in the vicinity of the movable machine part and the movable machine part being controlled by a process controller is controlled. The sensor system includes several single photon avalanche diode (SPAD) distance sensors. The sensor system is designed to distinguish between several different positions of the movable machine part and several different positions of the object. The monitoring device is designed to determine the position of the movable machine part exclusively by means of the sensor system. Furthermore, the monitoring device is designed to use the positions of the movable machine part and the position of the object detected by the sensor system to recognize a dangerous situation and, if a dangerous situation exists, to send a braking and / or switch-off and / or evasive signal to a safety input of the movable machine part send. The monitoring device is independent of the process control.

In other words, the monitoring device (e.g. exclusively) recognizes itself, i.e. without being dependent on data from the machine part or a process control, where the movable machine part is currently located. The monitoring device also detects where the object, e.g. a person, a hand or a leg of the person or another type of obstacle for the movable machine part, is currently located.

By using the SPAD distance sensors, which can be made very compact and also cost-effective, the monitoring device can have a small footprint and can be manufactured in a cost-effective and therefore economical manner. Due to the small space requirement, the monitoring device is particularly suitable for protecting small robots.

The SPAD distance sensors can each have their own light source that repeatedly emits light pulses. Reflected light pulses are received by one or more single photon avalanche diodes, with the distance to an object which reflected the light pulse can be deduced from the transit time of the light pulse. The SPAD distance sensors can each be set up to detect a distance to an object in precisely one spatial direction or in a conical spatial area. The use of several SPAD distance sensors enables the sensor system to set up a monitoring area in which the position of the movable machine part and the object can be determined by means of the SPAD distance sensors. The SPAD distance sensors are therefore time of flight (TOF) sensors.

Based on the positions of the object and machine part, which are known to the monitoring device, it can be recognized whether a dangerous situation is present. A dangerous situation can be present, for example, if the object and the machine part come too close. In this case, the monitoring device generates a braking and / or switch-off and / or evasive signal, which is sent directly to the safety input of the machine part.

The invention makes use of the fact that the direct detection of the positions of the object and machine part enables the position to be recorded particularly quickly, since there is no need to wait for data from the machine part or the robot or a process control. The use of the safety input on the machine part also contributes to rapid deceleration or shutdown of the machine part, since such a safety input can stop the machine part or the robot within a very short time.

The invention thus creates a monitoring device which, due to its own sensor system (i.e. due to the SPAD distance sensors) and the use of the safety input on the machine part, provides a simple and quick way of preventing accidents with the machine part.

In addition, the invention makes it possible to dispense with very powerful and therefore expensive industrial controls, so that the invention can also be used in small and simple applications. This opens up new areas of application for human-robot collaborations.

The monitoring device according to the invention is also independent of the industrial control / process control of the robot used in each case. A complex adaptation of the monitoring device to the respective process control can therefore be dispensed with.

Various aspects of the monitoring device are explained in greater detail below.

The sensor system is preferably designed to detect at least three or four different positions of the movable machine part and / or the object. This makes it possible that the sensor system not only supplies information about whether, for example, a person is present or not, but that the sensor system also supplies information about the location of the machine part or the object. The detection of the position of the machine part and / or object can this also takes place when there is no hazardous situation and the object is, for example, several meters away from the machine part. The detection can, for example, have an accuracy of approximately one centimeter.

The SPAD distance sensors can be arranged at various positions in the vicinity of the machine part. In this way, the various SPAD distance sensors can look at the machine part from different viewing directions. A respective position of the machine part in space can then be deduced from the different measured values (for example from different distance measured values) of the sensors. In the same way, by looking at the measurement data from the various sensors together, the position of the object can also be recorded both absolutely and relative to the machine part. The position of the machine part and / or the object is preferably also detected by means of the sensor system when there is no dangerous situation.

The monitoring device can have a computing unit which processes the data supplied by the sensor system and preferably calculates the positions of the movable machine part and the object. The arithmetic unit can also recognize the presence of the dangerous situation on the basis of the positions and also send the braking and / or switch-off and / or evasive signal to the safety input of the movable machine part.

The speed of the detection of a dangerous situation by the computing unit can also be increased by using a circuit adapted to the data signals of the sensor system as the computing unit. For example, the processing unit can have a microcontroller, an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit) that is adapted to the required calculations and can perform them at high speed.

The movable machine part can in particular be a robot, preferably a safe small robot. The movable machine part can be designed to machine a workpiece by means of a tool.

Advantageous further developments of the invention can be found in the description, the drawings and the subclaims.

According to the invention, the monitoring device is designed to determine the position of the movable machine part exclusively by means of the sensor system. The position of the object can also be determined exclusively using the sensor system. The monitoring device does not need any information from a process control or other external components, which avoids delays caused by such external components.

In other words, the monitoring device is preferably arranged at least in part independently of the movable machine part and at least in part at a distance from the movable machine part. This means that the monitoring device is, for example, not coupled to a control or process control of the machine part, but rather is independent of it. The monitoring device is also not integrated into the machine part, for example, and is thus arranged at least in part at a distance from the machine part.

The monitoring device preferably comprises a communication output for data transmission to the safety input of the movable machine part, the communication output being designed to transmit data only from the monitoring device to the safety input. There is therefore no return channel from the safety input to the monitoring device. The communication output thus only provides communication in one direction (i.e. unidirectional), namely from the monitoring device to the safety input.

According to a further advantageous embodiment, the monitoring device is designed to communicate with the movable machine part exclusively by unidirectional communication by means of the braking and / or switch-off and / or evasive signal. As an alternative or in addition, the monitoring device can be designed to recognize a dangerous situation solely on the basis of the positions of the movable machine part detected by means of the sensor system and the detected position of the object.

Due to the exclusive use of the sensor system for recording the positions of the machine part and object, the monitoring device does not need any information from a process controller or other external components, which avoids delays caused by such external components.

In addition to the unidirectional communication by means of the braking and / or switch-off and / or evasive signal, there is in particular no data communication between the movable machine part, or its process control, and the monitoring device. The monitoring device is therefore preferred with regard to data communication independently or independently of the movable machine part.

The monitoring device is preferably designed to calculate a position of the movable machine part and of the object in three-dimensional space, for example in three-dimensional Cartesian coordinates or in polar coordinates. In the case of larger machine parts and / or objects, several positions of the machine part and / or the object can be determined. For this purpose, the machine part and / or the object in its entirety can be detected by the sensor system. Alternatively, for example, only that part of the machine part can be monitored by means of the sensor system from which a hazard for the object can arise. This can be, for example, the area in the vicinity of a tool of the machine part.

Likewise, the sensor system can only detect or monitor the movable machine part in certain areas. The position of the machine part can then be derived from a respective unique signature of the monitoring data of the sensor system.

For example, a first position can indicate where the end of a robot arm is located. A second position, on the other hand, can represent the point in space at which the base of the robot arm is currently located. The distance between the machine part and the object can then be calculated from the position of the machine part and the object, the distance being the distance between the areas of the machine part and the object that are closest to one another.

Alternatively or additionally, it is possible that the SPAD distance sensors are arranged in such a way that the machine part moves past different sensors one after the other during operation, the sensors acting as light barriers or light sensors and tracking the movement of the machine part using the "triggered" sensors can be.

For example, when installing the monitoring device, the movable machine part can be moved, e.g. automatically, into various known positions. The known positions can then be compared with the measurement data of the sensor system in order to teach the positions to the sensor system (“teach-in”).

According to a further advantageous embodiment, the movable machine part comprises a collaborative robot. This means that the robot is designed to carry out work processes together with a human. For example, the collaborative robot can be the safe small robot already mentioned above. Such a collaborative robot can have a force limit. The maximum force that the robot can exert before a movement is automatically stopped is then set in such a way that in the event of a collision between the robot and a person, the application of force cannot lead to serious injuries. In addition, the robot can have edge-free, round or soft outer contours, at least in some areas, in order to distribute a possible collision force over a large area. This reduces the risk of cuts and the like.

A dangerous situation is preferably considered to be recognized when the distance between the movable machine part and the object falls below a predetermined minimum distance. The minimum distance can be defined, for example, in the range from 2 to 50 cm. Due to the minimum distance, there is a moving protective area around the movable machine part. This means that a movement of the movable machine part leads to a constantly changing protection area. The protection area is the area in which the object must not be located, since a dangerous situation is then recognized and the machine part is braked or stopped.

The changing protection area can, for example, also depend on whether, for example, a workpiece has been gripped or a gripper of the movable machine part is empty. In order to avoid the need for a return channel of the control, one of the sensors of the sensor system can be used to determine the occupancy of the gripper, for example. In this way, various types of information can then be provided by the sensor system, which are used to secure the tool area, to determine the position of the robot and to check the occupancy of the gripper that may be used.

The SPAD distance sensors preferably collectively record the monitoring area, for example by merging the data from different sensors (i.e. SPAD distance sensors). A single SPAD distance sensor can each cover a sub-area of the monitored area, with adjacent sub-areas preferably overlapping. The monitoring area is the area in which the sensor system is able to determine the position of the object and / or the machine part. The aforementioned protection area is a part of the monitoring area into which the object is not allowed to penetrate, with a dangerous situation being considered to be recognized when the object penetrates into the protection area.

The monitoring device is preferably designed, when it is recognized that machining of the workpiece is imminent, to switch off the sensor system temporarily at least partially or to hide its measured values in order to enable contact between the movable machine part and the workpiece. Without such a shutdown, the monitoring device could detect the intrusion of the workpiece into the protected area and then stop the movable machine part. In order to enable contact between the machine part and the workpiece, the sensor system can be at least partially switched off shortly before the workpiece is reached (what is known as “muting”). During the shutdown of the sensor system, the movable machine part and in particular a tool attached to the machine part can be brought into contact with the workpiece.

According to a further advantageous embodiment, the sensor system is designed to enclose at least the position of a tool fastened to the movable machine part by means of a (e.g. further) protection area and to detect an intrusion of the object into the protection area. The sensor system or the monitoring device does not have to monitor the entire machine part and enclose it with a protection area, but it is sufficient to simply enclose the tool with a protection area.

The tool (especially when it is used) poses a particular danger to people. The tool can be detected directly by means of the optical sensors, for example. Alternatively, the position of the tool can also be determined indirectly, for example based on the position of further areas of the machine part.

It is possible to only enclose the tool by means of the protection zone. This is possible, for example, with safe small robots, which can detect other collisions themselves and for which a maximum force is limited. The protection area can be set up around the tool like an “optical cage”.

The monitoring device is preferably designed to detect the direction of movement of the movable machine part and / or the direction of movement of the object and also to recognize a dangerous situation on the basis of the detected direction (s) of movement. In addition to determining the positions of the machine part and the object, the direction of movement can also be recorded. In addition to the direction of movement, the speed of the machine part and / or of the object in the respective direction of movement can preferably also be determined. Using the direction of movement and / or the speed, a probability of a collision between the machine part and the object can be calculated. If the probability exceeds a predetermined threshold value, a dangerous situation can be considered recognized.

The protected area moved along with the robot or the movable machine part can preferably be enlarged and reduced as a function of the speed of the movement of the movable machine part and / or the speed of the object. The higher the speed of the machine part and / or the object, the larger the protection area that can be selected.

The invention further relates to a process system with a movable machine part, in particular for machining a workpiece, the movable machine part being controlled by a process controller. The process system comprises a monitoring device that is independent of the movable machine part and independent of the process control. The monitoring device comprises at least one contactless sensor system for detecting the position of the movable machine part and for detecting the position of an object in the vicinity of the movable machine part. The monitoring device is designed to determine the position of the movable machine part exclusively by means of the sensor system. The sensor system comprises several single photon avalanche diode (SPAD) distance sensors and is designed to distinguish between several different positions of the movable machine part and several different positions of the object. The monitoring device is designed to use the positions of the movable machine part and the object detected by means of the sensor system to recognize a dangerous situation and, if the dangerous situation exists, to send a braking and / or switch-off and / or evasive signal to a safety input of the movable machine part in order to to slow down the movable machine part, to evade and / or to bring it to a standstill.

According to an advantageous embodiment, the SPAD distance sensors are (only) partially attached to the movable machine part. This means that only a subset of the SPAD distance sensors is attached to the movable machine part. In this case, at least the SPAD distance sensors attached to the movable machine part are arranged in a modular manner and define a protection area adapted to the tool. The protected area, which is observed by the SPAD distance sensors, can surround the tool at a predetermined distance. The distance can vary depending on the response time of the Sensor and the time necessary to stop a movement of the movable machine part and / or the tool can be selected. For this purpose, the SPAD distance sensors can be arranged adjacent to the tool on the movable machine part. Due to the arrangement in the immediate vicinity of the tool and the use of several SPAD distance sensors, dead zones of the monitoring can be avoided, since the contour of the protected area can be easily adapted to the area stressed by the tool. Even a complex geometry of the protected area can be safeguarded with precise contours using the modularly arranged SPAD distance sensors, for example to allow a person to approach a certain area. In addition, it is made possible to simplify the protection of the tool in the case of movable machine parts with complex movement profiles, since the SPAD distance sensors are arranged in a stationary manner relative to the "danger point".

According to an advantageous embodiment, the SPAD distance sensors are designed to collectively detect a monitoring area, each SPAD distance sensor detecting at least one sub-area of the monitoring area, with adjacent sub-areas preferably overlapping. The joint detection of the monitoring area can - as explained above - take place e.g. by merging the data from the individual sensors.

According to a further advantageous embodiment, the movable machine part is designed to assume a predetermined reference position, the monitoring device being set up to carry out a self-test while the movable machine part is in the reference position. In the self-test, position data of the movable machine part acquired by the sensor system are preferably compared with expected position data. A medium safety performance level can be achieved in a simple manner by means of the reference position and the self-test, since the correct function of the sensor system can be checked using the reference position. The sensor system is functioning correctly, for example, when the position data of the movable machine part recorded by the sensor system in the reference position do not differ from the expected position data by more than a predetermined threshold value. The reference position can be assumed by stopping the machine part or only briefly "while driving past" (i.e. without stopping the machine part). The self-test preferably takes place in the vicinity of the machining position for the workpiece.

According to a further advantageous embodiment, the sensor system comprises SPAD distance sensors, which are arranged in a stationary manner and preferably at a distance from the movable machine part. In addition to the SPAD distance sensors arranged adjacent to the tool on the machine part, the sensor system can thus also include further SPAD distance sensors which are, for example, independent and spaced from the movable machine part.

Optical reference marks are preferably attached to the movable machine part. The reference marks simplify position detection using the optical sensors, i.e. the SPAD distance sensors. The reference marks can therefore be optimized for detection by means of the SPAD distance sensors.

• - der bewegbare Maschinenteil von einer Prozesssteuerung gesteuert wird,
• - die Überwachungseinrichtung unabhängig von der Prozesssteuerung ist,
• - die Überwachungseinrichtung mittels zumindest eines berührungslosen Sensorsystems jeweils mehrere verschiedene Positionen des bewegbaren Maschinenteils und mehrere verschiedene Positionen eines Objekts erfasst,
• - die Überwachungseinrichtung die Position des bewegbaren Maschinenteils ausschließlich mittels des Sensorsystems bestimmt,
• - das Sensorsystem mehrere Single-Photon-Avalanche-Dioden-(SPAD)-Distanzsensoren verwendet, um die Positionen des bewegbaren Maschinenteils und des Objekts zu erfassen,
• - die Überwachungseinrichtung anhand der mittels des Sensorsystems erfassten Positionen des bewegbaren Maschinenteils und des Objekts eine Gefahrensituation erkennt und bei Vorliegen der Gefahrensituation ein Brems- und/oder Abschalt- und/oder Ausweichsignal an einen Sicherheitseingang des bewegbaren Maschinenteils sendet, um den bewegbaren Maschinenteil zu verlangsamen, ausweichen zu lassen und/oder zum Stillstand zu bringen.

Finally, the invention relates to a method for monitoring a movable machine part by means of a monitoring device, in which

• - the movable machine part is controlled by a process controller,
• - the monitoring device is independent of the process control,
• the monitoring device detects several different positions of the movable machine part and several different positions of an object by means of at least one contactless sensor system,
• - the monitoring device determines the position of the movable machine part exclusively by means of the sensor system,
• - the sensor system uses several single photon avalanche diode (SPAD) distance sensors to detect the positions of the movable machine part and the object,
• - the monitoring device recognizes a dangerous situation based on the positions of the movable machine part and the object detected by means of the sensor system and, if the dangerous situation exists, sends a braking and / or switch-off and / or evasive signal to a safety input of the movable machine part in order to slow down the movable machine part to evade and / or to bring to a standstill.

For the method according to the invention and the process system according to the invention, the statements relating to the monitoring device according to the invention apply accordingly, in particular with regard to advantages and preferred embodiments.

• 1 ein Prozesssystem mit einem Roboter und einer Überwachungseinrichtung; und
• 2 einen schematischen Aufbau der Komponenten des Prozesssystems von 1.

The invention is described below purely by way of example with reference to the drawings. Show it:

• 1 a process system with a robot and a monitoring device; and
• 2 a schematic structure of the components of the process system of 1 .

1 shows a process system 10 , which is a movable machine part in the form of a collaborative robot 12th having. The robot 12th is used to machine a workpiece 14th . For machining the workpiece 14th includes the robot 12th a tool 16 , for example a drill.

The process system 10 further comprises a plurality of stationary SPAD (single photon avalanche diodes) distance sensors 18 as well as with the robot 12th Moving SPAD distance sensors 20th . The SPAD distance sensors 18th , 20th are designed for distance measurement.

The fixed SPAD distance sensors 18th collectively capture a monitoring area 22nd in which the robot 12th and also an object, here for example as a human operator 24 shown, can move. In the surveillance area 22nd the workpiece is also located 14th .

That for processing the workpiece 14th serving tool 16 is covered by a protection area 26th included, which is caused by the moving SPAD distance sensors 20th is observed and monitored. The protection area 26th is due to the size of the tool 16 customized. The operator takes action 24 in the protection area 26th one, becomes the tool 16 stopped immediately as explained in more detail below.

Besides the one in the 1 shown protection area 26th who takes care of the tool 16 around, the stationary SPAD distance sensors observe 18th one with the robot 12th moving dynamic protection area 27 , which is a sub-area of the monitored area 22nd is the robot 12th surrounds and changes depending on the speed of movement of the robot 12th enlarged and reduced.

In 2 is now the schematic interconnection of the process system 10 from 1 shown. In the process system 10 takes over process control 28 the control of the robot 12th . The process control 28 in particular ensures that the workpiece 14th is processed correctly. This is what process control is for 28 in bidirectional communication with the robot 12th .

A monitoring device 30th of the process system 10 includes the already mentioned stationary and moving SPAD distance sensors 18th , 20th . The SPAD distance sensors 18th , 20th are all with a computing unit in the form of a SPAD master 32 coupled. To the robot 12th The SPAD-Master can switch off in a dangerous situation 32 to a fast security entrance 34 of the robot 12th send a braking and / or shutdown and / or evasive signal. The SPAD master 32 is for this purpose by means of a unidirectional communication output 36 with the security entrance 34 connected.

The SPAD distance sensors transmit during operation 18th , 20th light pulses into the monitored area by means of light sources (not shown) 22nd and determine a respective time of flight of the reflected light signals. A distance of the respective SPAD distance sensor can be calculated from the light travel time 18th , 20th to the robot 12th or to the operator 24 be determined. From the determined distances and the known position of the stationary SPAD distance sensors 18th , can change the positions of the robot 12th and the operator 24 in the monitoring area 22nd be determined.

When the robot moves 12th now finds a continuous detection of the position of the robot 12th and also the position of the tool 16 using the stationary SPAD distance sensors 18th instead of. The position of the robot 12th is constantly changing with the operator's position 24 compared to quickly identify a possible collision or dangerous situation.

The robot moves 12th on the workpiece 14th closed, the robot pauses 12th shortly before reaching the workpiece 14th in position for a predetermined period of time. This persistence is controlled by the SPAD master 32 detected, with the then determined position of the robot 12th is compared with an expected position in order to check the functionality of the monitoring device 30th perform.

Alternatively, the function test can also be performed while driving past (ie without stopping the robot 12th ), which is due to the rapid measuring processes of the sensors 18th , 20th is possible. The time saved in this way can contribute to maintaining the required cycle times and increasing productivity.

The robot moves 12th then on to the workpiece 14th to, the moving SPAD distance sensors 20th shortly before reaching the workpiece 14th switched off briefly ("muting") to the robot 12th not by recognizing the workpiece 14th as an impermissible object in the protection area 26th to stop.

Once the robot 12th the workpiece 14th by means of the tool 16 processed, the moving SPAD distance sensors are processed 20th activated again, while machining the workpiece 14th the protection area 26th (for example dynamically) is reduced.

Moves, for example, the operator 24 his hand in the protection area 26th into it, this is done by changing the measurement signal from the SPAD distance sensors that are moved along with it 20th recorded, whereupon the SPAD master 32 classifies this as a dangerous situation and sends a switch-off signal to the fast safety input 34 sends what leads to the immediate shutdown of the robot 12th including its tools 16 leads.

The SPAD master recognizes in a similar way 32 a dangerous situation when the robot is 12th moves and the operator in its movement 24 approaching too quickly or too strongly. Too fast an approach and / or too close an approach (ie an approach where the distance between robots 12th and operator 24 falls below a predetermined threshold value) can by means of the stationary SPAD distance sensors 18th are recorded. The SPAD master 32 then generates a braking and / or switch-off and / or evasive signal, which is transmitted via the communication output 36 to the fast security entrance 34 of the robot 12th is sent, whereupon the robot 12th decelerates, evades or stops completely.

Out 2 it can be seen that data transmission is exclusively from the monitoring device 30th towards the robot 12th he follows. A data transfer from the robot 12th or its process control 28 towards the monitoring device 30th is not needed. Because the monitoring device 30th all necessary information about the position of the robot 12th and the operator 24 only recorded by the monitoring device 30th do not wait for the required information, for example from process control 28 to be delivered. For this reason, the monitoring device 30th react particularly quickly to dangerous situations, with the addition of the quick safety entrance 34 of the robot 12th is used for switching off, which does not take a detour via the process control 28 makes necessary.

The security of the entire process system 10 can be increased due to the fast response time achieved in this way.

List of reference symbols

10

Process system

12th

robot

14th

workpiece

16

tool

18th

Fixed SPAD distance sensor

20th

Moving SPAD distance sensor

22nd

Monitoring area

24

operator

26th

Protection area

27

dynamic protection area

28

Process control

30th

Monitoring device

32

SPAD master

34

fast security entrance

36

Communication output

Claims (14)

Monitoring device (30) for monitoring a movable machine part (12), which is used in particular for processing or handling a workpiece (14), the movable machine part (12) being controlled by a process controller (28), the monitoring device (30) at least one Contactless sensor system (18, 20, 32) for detecting the position of the movable machine part (12) and for detecting the position of an object (24), for example a person or an obstacle, in the vicinity of the movable machine part (12), the Sensor system (18, 20, 32) is designed to distinguish between several different positions of the movable machine part (12) and several different positions of the object (24), the sensor system (18, 20, 32) having several single-photon avalanche Diode (SPAD) distance sensors (18, 20), the monitoring device (30) being designed to detect by means of the sensor system (18, 20, 32) Most positions of the movable machine part (12) and the object (24) to recognize a dangerous situation and to send a braking and / or switch-off and / or evasive signal to a safety input (34) of the movable machine part (12) if the dangerous situation exists wherein the monitoring device (30) is independent of the process control (28), characterized in that the monitoring device (30) is designed to determine the position of the movable machine part (12) exclusively by means of the sensor system (18, 20, 32). Monitoring device (30) after Claim 1 , characterized by a communication output (36) for data transmission to the safety input (34) of the movable machine part (12), the communication output (36) being designed to transmit data only from the monitoring device (30) to the safety input (34). Monitoring device (30) after Claim 1 or 2 , characterized in that the monitoring device (30) is designed to communicate with the movable machine part (12) exclusively by means of unidirectional communication by means of the braking and / or switch-off and / or evasive signal, and / or exclusively by means of the means of the sensor system (18, 20, 32) detected positions of the movable machine part (12) and the detected position of the object (24) to detect a dangerous situation. Monitoring device (30) according to at least one of the preceding claims, characterized in that a dangerous situation is considered recognized when the distance between the movable machine part (12) and the object (24) falls below a predetermined minimum distance. Monitoring device (30) according to at least one of the preceding claims, characterized in that the monitoring device (30) is designed to switch off the sensor system (18, 20, 32) at least partially when it is detected that machining of the workpiece (14) is imminent or hide its measured values in order to enable contact between the movable machine part (12) and the workpiece (14). Monitoring device (30) according to at least one of the preceding claims, characterized in that the sensor system (18, 20, 32) is designed to at least determine the position of a tool (16) attached to the movable machine part (12) by means of a protected area (26) enclose and detect a penetration of the object (24) into the protected area (26). Monitoring device (30) according to at least one of the preceding claims, characterized in that the monitoring device (30) is designed to detect the direction of movement of the movable machine part (12) and / or the object (24) and also based on the detected direction of movement or the detected Directions of movement to recognize a dangerous situation. Process system (10) with a movable machine part (12), in particular for machining a workpiece (14) by means of a tool (16), the movable machine part (12) being controlled by a process controller (28), and with a monitoring device (30) which is independent of the movable machine part (12), the monitoring device (30) having at least one contactless sensor system (18, 20, 32) for detecting the position of the movable machine part (12) and for detecting the position of an object (24) in the surroundings of the movable machine part (12), the sensor system (18, 20, 32) being designed to distinguish between several different positions of the movable machine part (12) and several different positions of the object (24), the sensor system (18 , 20, 32) has several single photon avalanche diode (SPAD) distance sensors (18, 20), the monitoring device (30) being designed based on the means of the sensorsy stems detected positions of the movable machine part (12) and the object (24) to recognize a dangerous situation and to send a braking and / or switch-off and / or evasive signal to a safety input (34) of the movable machine part (12) if the dangerous situation is present , in order to slow down, evade and / or bring the movable machine part (12) to a standstill, and wherein the monitoring device (30) is independent of the process control (28) characterized in that the monitoring device (30) is designed which To determine the position of the movable machine part (12) exclusively by means of the sensor system (18, 20, 32). Process system (10) according to Claim 8 , characterized in that the SPAD distance sensors (20) are partially attached to the movable machine part (12), at least the sensors (20) attached to the movable machine part (12) being arranged in a modular manner and one adapted to the tool (16) Define the protection area (26). Process system (10) according to Claim 9 , characterized in that the SPAD distance sensors (18) are designed to collectively capture a monitoring area (22), each SPAD distance sensor (18) capturing at least one sub-area of the monitoring area (22), with adjacent sub-areas preferably overlapping . Process system (10) according to at least one of the Claims 8 until 10 , characterized in that the movable machine part (12) is designed to assume a predetermined reference position, the monitoring device (30) being set up to carry out a self-test while the movable machine part (12) is in the reference position, in which preferably by the sensor system (18, 20, 32) detected position data of the movable machine part (12) are compared with expected position data. Process system (10) according to at least one of the Claims 8 until 11 , characterized in that the sensor system comprises SPAD distance sensors (18) which are stationary and spaced apart from the movable machine part (12). Process system (10) according to at least one of the Claims 8 until 12th , characterized in that optical reference marks are attached to the movable machine part (12). Method for monitoring a movable machine part (12) by means of a monitoring device (30), in which - the movable machine part (12) is controlled by a process controller (28), - the monitoring device (30) is independent of the process control (28), - the monitoring device (30) detects several different positions of the movable machine part (12) and several different positions of an object (24) by means of at least one contactless sensor system (18, 20, 32), - the monitoring device (30) determines the position of the movable machine part (12) exclusively by means of the sensor system (18, 20, 32), - The sensor system (18, 20, 32) uses several single photon avalanche diode (SPAD) distance sensors (18, 20) to detect the positions of the movable machine part (12) and the object (24), - the monitoring device (30) recognizes a dangerous situation based on the positions of the movable machine part (12) and the object (24) detected by means of the sensor system (18, 20, 32) and, if the dangerous situation exists, a braking and / or shutdown and / or sends an evasive signal to a safety input (34) of the movable machine part (12) in order to slow down the movable machine part (12), allow evasive action and / or bring it to a standstill.

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