DE102015220493A1 - Verification of a position of a manipulator system - Google Patents

Abstract

The present invention relates to a method for operating a manipulator system (1), which may in particular comprise a driverless transport system. A protective field of the manipulator system (1) is monitored by means of a monitoring device (2). According to the method, a system position and / or system orientation of the manipulator system is determined, and environment information (3) relating to an environment of the manipulator system is provided. Furthermore, a first (4) and a second (5) protective field are formed based on the environmental information (3) and the determined system position and / or orientation. Based on at least one injury information for the first (4) and the second (5) protective field, the particular system position and / or system orientation (6) of the manipulator system (1) is verified.

Description

1. Technical area

The present invention relates to a method for operating a manipulator system, which may in particular comprise a driverless transport system, and wherein a protective field of the manipulator system is monitored by means of a monitoring device. Furthermore, the invention relates to a corresponding manipulator system.

2. Technical background

Automatic guided vehicle systems (AGVs) are often used in production plants, for example, to transport components or workpieces from one workstation to another workstation. A driverless transport system can have its own drive, and be controlled automatically. Driverless transport systems can also be used to move manipulators or industrial robots so that they can perform certain operations at different workstations.

In general, a driverless transport system can be considered as a conveyor system, which may include at least one driverless transport vehicle. The vehicle can be multi-directional and in particular omnidirectional movable. For this purpose, it may have corresponding omni-directional wheels to allow high mobility and flexibility of the driverless transport system.

Driverless transport vehicles are controlled automatically. For this purpose, for example, an in-vehicle control device can be used, which drives corresponding drives of the driverless transport system in order to effect a desired movement of the vehicle. The control device may be based on a program which specifies the movement of the vehicle, characterized by the direction and speed.

In order to enable a safe operation of a driverless transport system in a workshop, they are often equipped with laser scanners, which can monitor a so-called protective field (often called warning field, security area or security area). In particular, the protective field can cover a horizontal area around the driverless transport system. If, for example, an obstacle, such as a person, enters the protective field, a violation of the protective field can be detected or detected by means of the laser scanner. In response, the driverless transport system may stop to avoid a potential collision. Thus, a safe human-robot collaboration (MRK) is possible. Instead of or in addition to such an emergency stop, further reactions can take place. Thus, for example, a corresponding signal can be output or a speed of the system can be reduced.

Driverless transport systems usually have navigation software and corresponding sensors in order to navigate the driverless transport system in this environment. In order to determine the position of the driverless transport system, in particular laser scanner can be used, which are mounted on the driverless transport system. These can perform distance measurements to objects in the vicinity of the driverless transport system. However, such distance measurement data can be inaccurate, and thus do not allow precise or sufficiently reliable localization of the driverless transport system in the environment with regard to given safety aspects or safety specifications. If a position is insufficiently known, this can lead to following errors: For example, as a result, protective fields can be unfavorably dimensioned so that a known object in the environment can lead to an unwanted violation of the protective field or location-dependent security mechanisms are activated / deactivated incorrectly.

In the control device, a position of the driverless transport system can be continuously tracked and updated. For this purpose, GPS data, distance measurement data from laser scanners, or odometry can be used. Due to several sources of error, such as uneven floors or slippage, the position stored in the control device can be faulty.

The position of a driverless transport system at a workstation can be verified by additional sensors, which allow, for example, an environment scan. However, this is usually associated with a considerable expenditure of time and money, since this additional sensor technology and the corresponding application are needed.

There is thus the need to precisely verify a currently assumed position, for example, in a control device stored position of a manipulator system, so that this position is particularly useful for other security aspects. In particular, should be feasible with the present invention, a highly reliable position verification.

These and other objects will become apparent from the following description by a method according to claim 1 and a system according to claim 13.

3. Content of the invention

The present invention relates to a method for operating a manipulator system. The manipulator system may include a manipulator, which may in particular have a mobile base. Preferably, the manipulator system is a driverless transport system. Preferably, the manipulator system comprises a driverless transport vehicle, which in particular can carry and move a manipulator. The manipulator system is particularly preferably designed as a manipulator with a mobile base. The person skilled in the art will understand that a manipulator can consist of a number of movable links or axes that are chained together and can form a robot's robotics. In turn, a robot can be a freely programmable, program-controlled handling device.

A protective field of the manipulator system is monitored by means of a monitoring device. By monitoring the protective field, it can be detected, for example, that an object or obstacle is located in the protective field, and, if appropriate, a corresponding reaction of the manipulator system can be initiated. By means of the monitoring device, a protective field violation can thus be detected or detected, and a corresponding reaction can take place. For example, a protective field violation can be triggered by means of the monitoring device when a person enters the protective field, and consequently an emergency stop of the manipulator system is initiated. Additionally or alternatively, a warning signal can be issued. It is also possible to detect only the protective field violation without a reaction taking place. The monitoring device preferably comprises one or more laser scanners for detecting objects in the protective field. Such laser scanners work reliably and allow to meet high safety requirements. In general, the detectable object can be any body which occupies a certain space in an environment of the manipulator system and can be detected by means of the monitoring device or can be detected by it. The monitoring device does not have to recognize and identify the object, but rather it is sufficient for a safe use of the manipulator system that the mere presence of the object in the protected area is detected.

The method includes determining a system position and / or system orientation of the manipulator system. The particular system position and / or orientation may also be considered as the assumed position and / or orientation of the manipulator system, which need not correspond to the actual position or orientation of the manipulator system. The particular system position and / or orientation can also be stored or stored in a control device of the manipulator system. It can be continuously updated during operation based on odometry or distance measurement data, which may be captured by laser scanners, for example. In particular, the particular system position may be used to navigate and control the manipulator system, and may be taken into account, in particular, for safety aspects, such as for protection field adaptation. By means of the present method, this particular system position can be verified. The same applies to the system orientation of the manipulator system, which describes an assumed orientation or orientation of the manipulator system in space. Preferably, the system position and / or system orientation of the manipulator system is determined based on odometry and / or radio-based. The determination of the system position and / or orientation can thus take place by means of a wireless position determination. In this case, in particular WLAN technology can be used, or a local, for example, a factory built localization technique can be used, such as the so-called indoor GPS. Also laser triangulation, laser tracker or 3D image processing technique can be used to determine the system position and / or orientation. The particular system position and / or orientation is initially assumed to be correct and should be checked in the further course of the procedure, ie verified.

Furthermore, the method comprises providing environment information concerning an environment of the manipulator system. The environment information may include information about known obstacles in the environment of the manipulator system. These known obstacles can already be taken into account when programming the manipulator system, while an unknown obstacle can be an object which was not considered at the time of programming the manipulator system or could not be taken into account. Known obstacles or objects can also be detected after programming and taken into account in the environment information. By means of the environmental information can thus be described, where and in which orientation the manipulator system with respect to the environment of the manipulator system, based on the specific or assumed position and / or orientation. Based on the environmental information, for example, distances between the manipulator system and Calculate obstacles in the area. For example, by means of the environmental information a contour of the environment can be described, which can be viewed by means of the monitoring device. This visible contour can be described relative to the particular system position and / or orientation in the environment information. The environment information is preferably stored in the control device of the manipulator system.

Furthermore, the method comprises forming a first protective field based on the environmental information and the determined system position and / or system orientation. The first protective field is dimensioned such that it is not violated in the case of a correctly determined system position and / or system orientation. The person skilled in the art understands that the correctly determined system position and / or orientation need not precisely describe the exact, actually present system position and / or orientation, but can lie within tolerable error limits. For example, the first protective field can be designed such that it covers an area in which there are no known obstacles of the environment. In this case, a certain, if preferably minimal, distance between the boundary of the first protective field to objects or obstacles of the environment can be maintained. For example, the first protective field may extend to a wall of the environment based on the assumed position and / or orientation of the manipulator system. This first protective field is to be based on the environmental information, such as an environment map, and the particular system position and / or orientation of the manipulator system, so that a position and / or orientation of the manipulator system with respect to the environmental information may be described. Thus, in reality, the first protective field may be violated by an inappropriately determined system position and / or orientation due to known environmental obstacles. In any case, the first protective field is preferably defined such that, given a correctly determined system position and / or orientation, it is not injured by known obstacles of the environment.

Furthermore, the method comprises forming a second protective field based on the environmental information and the determined system position and / or system orientation. The second protective field is larger than the first protective field and is preferably chosen such that it is damaged by known obstacles of the environment. The second protective field is dimensioned such that it is violated if the system position and / or system orientation are correctly determined. The size of a protective field can generally be described by the area covered by the protective field. The second protective field can thus cover a larger area than the first protective field. Since the second protective field may be sized to be violated due to the environment, a known environmental obstacle may be within the second protective field, whether or not the particular system position and / or orientation is correct. The protective fields are preferably formed by the control device of the manipulator system.

Furthermore, the method comprises determining at least one injury information for the first and the second protective field. In this case, it can be determined in particular whether the first or second protective field is ever violated, and in particular a degree of violation of the second and possibly the first protective field can be determined. The degree of the injury can describe which areas of the protective fields are violated or whether a protective field is completely or only partially violated. The degree of injury can thus describe a degree of violation of the protective field. The determination of injury information preferably takes place in the control device of the manipulator system.

Furthermore, the method comprises verifying the determined system position and / or system orientation of the manipulator system based on the injury information. The first and second protective fields formed in accordance with the environment information and specific system position and / or orientation, or the use of these protective fields, makes it possible to draw conclusions as to whether the expected position or orientation of the manipulator system with respect to the environmental information is correct. Ultimately, it can be checked or verified whether the specific system position and / or orientation of the manipulator system are correct. The verification preferably takes place in the control device of

manipulator system

It is thus advantageously possible, during operation of the manipulator system or preferably of the driverless transport system, to verify a currently assumed system position and / or orientation taking into account the environmental information. By way of example, the first protective field may be dimensioned such that it is not violated if the determined system position and / or orientation are correct. The second protective field is larger than the first protective field and is thus injured by the environment. Now, if it is determined that the first protection field is actually not violated, while the second is completely or expected, the particular system position may be correct be verified, as well as the system orientation. Thus, the provided monitoring device can be used efficiently for a position and orientation verification, whereby no additional costs arise because the monitoring device can already be provided for the MRK-safe operation of the manipulator system. Since the analysis of protective fields by means of the monitoring device is very precise for safety-related aspects, a precise verification of the position and / or orientation is possible.

Each of the method steps may be performed during a standstill or movement of the manipulator system. Preferably, the determination of the injury information and / or the verification of the determined system position and / or system orientation take place during a movement of the manipulator system. A program sequence must therefore advantageously not be interrupted.

Preferably, the environment information includes an environment map, wherein the environment map includes structural information of at least one object in the environment. The environment map may include obstacles, objects or bodies, such as walls, columns, tables, workstations, corridors, etc. The environment map need not describe the complete environment of the manipulator system, but may at least provide information about obstacles or objects near the manipulator Manipulator system include. The particular system position and / or orientation of the manipulator system can be defined in particular with regard to the environment map. Based on the environment map, the first and second protection fields can be formed so efficiently that based on corresponding injury information, the particular system position and / or orientation can be efficiently verified with little effort.

In particular, preferably, the first and second protective field are formed based on the environmental information such that the object or known object is not located in the first protective field but at least partially in the second protective field. The object or obstacle thus does not violate the first protective field if the particular system position or orientation is correct, but the second protective field. If the specific system position or orientation is incorrect, the first protective field may also be violated. At least a different violation of the first and second protective field, in particular a different degree of injury, if the particular system position and / or orientation are incorrect.

Preferably, the first and / or second protective field covers an angle range around the manipulator system of less than 360 °, and further preferably covers an angular range of at most 10 °, more preferably of at most 20 °, more preferably of at most 30 °, more preferably of maximum 45 °, more preferably at most 60 °, and most preferably at most 90 °. The protective field (s) thus need not be completely stretched around the manipulator system, and may for example extend only in one direction of travel of the manipulator system. Preferably, by the first and / or second protective field, an angular range around the manipulator system of about 10 °, more preferably about 20 °. Further preferably about 30 °, more preferably about 45 °, more preferably about 60 ° and most preferably covered by about 90 °.

The injury information preferably describes whether the first protective field is violated, whether the second protective field is violated, and / or whether the first and second protective field are violated. Thus, it is first checked whether or which protective field is violated at all.

Preferably, determining the injury information further comprises determining which region of the first and second protection field is violated. An accurate analysis of the corresponding injury information allows a precise inference to the details of the mislocalization.

The first and / or the second protective field are preferably subdivided into a plurality of partial protective fields. Preferably, determining the violation information comprises determining if a predefined number of the partial protection fields are violated. This predefined number of partial protective fields may be preferably 50%, more preferably 70%, more preferably 90%, more preferably 95%, more preferably 99% and most preferably 100% of the total number of partial protective fields. For example, it may be sufficient for the verification if only four out of a total of 5 partial protection fields are injured or not injured as expected. Thus, it can be determined precisely whether an unknown object is in the first and / or second protective field, if necessary, and the corresponding area for the verification of the system position and / or orientation can be excluded. In particular, error tolerances can thus be specified, which enables the most efficient position and / or orientation verification possible.

In particular, preferably, each partial protective field covers an angle range around the manipulator system of 1 ° to 30 °, more preferably of 2 ° to 20 °, more preferably from 3 ° to 15 °, and most preferably from 5 ° to 10 °. Thus, depending on the particular application, efficient verification of system position and / or orientation can be performed.

Preferably, the method further comprises calculating a current position and / or orientation of the manipulator system based on the injury information. Thus, not only the specific or assumed system position and / or orientation are verified, but possibly also a correct position and / or orientation calculated. This includes in particular also an updating of the determined system position and / or orientation.

In particular, the current position and / or orientation of the manipulator system may be calculated based on an amount of injury to a violation of the first or second protective field. The information obtained from the injury information allows a precise inference to the details of a mislocalization.

Furthermore, the present invention relates to a manipulator system, comprising in particular a driverless transport system. The manipulator system comprises a monitoring device that is set up to monitor a protective field of the manipulator system. Furthermore, the manipulator system comprises a control device which is set up to carry out a method described above for operating a manipulator system. For this purpose, the manipulator system may comprise certain means enabling the described operation of the manipulator system and in particular the described position and / or orientation verification.

The term control device is to be understood broadly, since it may include many, even decentralized control devices, such as computers. In particular, it may comprise a plurality of different control devices, such as a control device for controlling an automated guided vehicle transport system, a control device for controlling the monitoring device, and a control device for controlling a manipulator, which is carried by the driverless transport system. Alternatively, the control device may consist of only a single suitable control device. The individual steps of the method can be stored on a computer-readable medium.

The monitoring device preferably comprises laser scanners for detecting objects in the protective field. Such laser scanners work reliably and allow to meet high safety requirements.

It will be understood by those skilled in the art that within the meaning of the invention more than two protective fields may be formed to allow for more refined verification of the particular system position and / or orientation.

4. Brief description of the drawings

In the following, the present invention will be described in detail with reference to the accompanying drawings. In the figures, like parts are identified by the same reference numeral. It shows:

1 schematically a manipulator system according to an embodiment;

2 schematically a manipulator system according to another embodiment;

3 schematically different configuration of protective fields;

4 a manipulator system according to another embodiment; and

5 a manipulator system according to another embodiment.

5. Description of preferred embodiments

In 1 is a manipulator system 1 shown on which two laser scanner 2 are provided. These laser scanners 2 can monitor a protective field as part of a monitoring device. Objects that exist in or enter the monitored protective field result in a protective field violation. This protective field violation can be output as a binary signal and an emergency stop or other reaction of the manipulator system 1 cause.

Furthermore, in the manipulator system 1 an environment information provided by means of which an expected contour 3 the environment with respect to a particular or assumed position and orientation of the manipulator system 1 can be described in the environment. The position and orientation can be determined by means of odometry or indoor GPS, and be considered as assumed position and orientation.

For verification of this assumed position and orientation is in particular of the control device of the manipulator system 1 a first protective field 4 which is just not violated if the particular system position and / or orientation are correct. The first protective field 4 is configured to the expected contour 3 the environment with respect to the assumed position and orientation of the manipulator system 1 , at no point the first protective field 4 hurt, like in 1 seen.

Furthermore, in particular by the control device of the manipulator system 1 a second protective field 5 formed, which is larger than the first protective field 4 is and is believed by, for example by the controller, that it is injured by the environment. Like in the 1 shown, becomes the second protective field 5 formed such that the expected contour 3 the environment with respect to the assumed position and orientation of the manipulator system 1 the second protective field 5 completely or partially injured.

Based on injury information, the assumed position and / or orientation can be verified. If the first protective field 4 and the second protective field 5 as expected, not violated or in particular completely violated, the particular system position and / or orientation of the manipulator system can be verified as correct.

In the in 2 The situation shown corrects the actual position or orientation 7 of the manipulator system 1 not with the expected position or orientation 6 match. In the situation presented here are adopted according to the assumed position and orientation 6 concerning the expected obstacle 3 Protective fields formed as with reference to 1 described. It should be based on this assumed position and orientation 6 a first protective field 4 ' not by the expected obstacle 3 be injured, a second protective field 5 ' should, however, as shown by the expected obstacle 3 get hurt.

The actual position and orientation 7 of the manipulator system 1 however, deviates from the assumed position and orientation 6 from. The actual relative position 10 of the obstacle causes a violation of the first 4 and second 5 Protective field that does not correspond to the assumed injury. The first protective field 4 will be in the area 8th unexpectedly injured. Furthermore, the second protective field 5 only in the area 9 , and not hurt as expected. It thus becomes the first protective field 4 injured and the second protective field 5 not hurt as expected. This initially allows the inference that the assumed position and orientation 6 , or the specific system position and orientation 6 not with the actual, current position and orientation 7 matches. Furthermore, from the type or degree of injury of the first 4 and second 5 Protective field a correct position and orientation 7 of the manipulator system 1 be determined.

In the 3 three different situations are shown, the different inference to an actual position and / or orientation of the manipulator system 1 enable. In situation (a) lies the actual contour image 10 between the first 4 and second 5 Protective field: the first protective field 4 is not injured by the actual environment, the second protective field 5 however completely. This corresponds to the situation in which the assumed position and orientation correspond exactly or substantially with the actual position and orientation.

In the situation (b) the 3 will be both the first 4 as well as the second 5 Protective field partially injured. The assumed position or orientation therefore does not match the actual position. From the degree of injury, it can be determined that the assumed orientation does not agree with the actual orientation.

In the situation (c) the 3 be both the first 4 as well as the second 5 Protective field completely injured. This allows the conclusion that the assumed position does not coincide with the actual position.

The environment map at an assumed position and / or orientation corresponds to the expected snapshot of the sensor such as laser scanner, if the assumed position and / or orientation is correct. Through targeted protective field configuration, the expected environment can now be verified. First, a first protective field 4 generated, which is the environment image 3 minus a certain tolerance threshold. If the system position and / or orientation are correct, this first protective field should be 4 do not be hurt. In the second step, a second protective field is created 5 formed, which is configured so that it the environment image 3 plus a certain tolerance threshold. If the system position and / or system orientation is correct, this second protective field should be 5 through the expected environmental contour 3 get hurt. If the system position and / or orientation are incorrect, the first protective field is violated or the second protective field is not violated as expected.

By examining the environment in several sections, ie with several protective fields, a precise conclusion can be drawn about the position of the driverless transport system.

In the 4 another embodiment is shown, in which the environment in several sections, which are radially divided, is checked. The ones from the laser scanners 2 outgoing radial laser beams are in sections, or partial protective fields, of about 10 ° around the manipulator system 1 divided. For each section, a positive or negative feedback on the coherence of the expected environmental contour is determined individually. Thus, a possible deviation from the assumed position or orientation can be deduced precisely. When in the environment of the manipulator system 1 unknown objects or obstacles, such as humans, this causes a violation of at least one of the protective fields, and in particular of the first protective field 4 although the assumed system position and / or orientation may be correct. By individually verifying the individual sections or partial protective fields, it is thus possible to determine whether the assumed position is correct and whether an unknown object is located in the protective field. For this purpose, it can be checked whether a number of uninjured sections of the first protective field 4 is greater than a predefined tolerance value, and then the verification is performed using these uninjured portions.

In the 5 another embodiment is shown. Here are the protective fields 4 . 5 only locally around the manipulator system 1 formed around. In this case, four checking directions or checking ranges a, b, c, d can be identified. Only these areas are examined for position and orientation verification. The first protective field 4 and second protective field 5 are formed only in these areas a, b, c, d. By evaluating the resulting injury information regarding the areas a, b, c, d and comparing it with an injury information to be expected based on the assumed position and orientation, the position of the manipulator system 1 be verified.

Claims (14)

Method for operating a manipulator system ( 1 ), comprising in particular a driverless transport vehicle, and wherein a protective field of the manipulator system ( 1 ) by means of a monitoring device ( 2 ), comprising: - determining a system position and / or system orientation ( 6 ) of the manipulator system; Providing environment information ( 3 ) concerning an environment of the manipulator system ( 1 ); - forming a first protective field ( 4 ) based on the environment information ( 3 ) and the particular system position and / or system orientation ( 6 ), the first protective field ( 4 ) is dimensioned such that, given a correctly determined system position and / or system orientation ( 6 ) is not violated; - forming a second protective field ( 5 ) based on the environment information ( 3 ) and the particular system position and / or system orientation ( 6 ), the second protective field ( 5 ) greater than the first protective field ( 4 ), the second protective field ( 5 ) is dimensioned such that, given a correctly determined system position and / or system orientation ( 6 ) get hurt; Determining at least one injury information for the first ( 4 ) and the second ( 5 ) Protective field; and - verifying the particular system position and / or system orientation ( 6 ) of the manipulator system ( 1 ) based on the injury information. Method according to claim 1, wherein the determination of the injury information and / or the verification of the system position and / or system orientation ( 6 ) during a movement of the manipulator system ( 1 ) respectively. Method according to claim 1 or 2, wherein the environment information ( 3 ) comprises an environment map, the environment map comprising structural information of at least one object in the environment. The method of claim 3, wherein forming the first ( 4 ) and second ( 5 ) Protective field is carried out in such a way that the object is not in the first protective field ( 4 ) but at least partially in the second protective field ( 5 ) lies. Method according to one of claims 1 to 4, wherein the first and / or second protective field ( 4 . 5 ) covers an angle range around the manipulator system of less than 360 °, and preferably an angle range of at most 10 °, more preferably of not more than 20 °, more preferably of not more than 30 °, more preferably of not more than 45 °, more preferably of not more than 60 ° and most preferably covers a maximum of 90 °. Method according to one of claims 1 to 5, wherein the injury information describes whether the first protective field ( 4 ), whether the second protective field ( 5 ) and / or whether the first and second protective fields ( 4 . 5 ) get hurt. The method of claim 1, wherein determining the injury information further comprises determining which region of the first (1). 4 ) or the second ( 5 ) Protective field is violated. Method according to one of claims 1 to 7, wherein the first ( 4 ) and / or the second ( 5 ) Is divided into a plurality of partial protection fields, and wherein determining the injury information comprises determining whether a predefined number of the partial protection fields is violated, wherein the predefined number of partial protection fields is preferably 50%, more preferably 70%, more preferably 90%, more preferably 95%, more preferably 99% and most preferably 100% of the total number of partial protection fields. Method according to claim 8, wherein each partial protective field covers an angular range around the manipulator system ( 1 ) from 1 ° to 30 °, preferably from 2 ° to 20 °, more preferably from 3 ° to 15 °, and most preferably from 5 ° to 10 °. Method according to one of claims 1 to 9, further comprising calculating a current position and / or orientation ( 7 ) of the manipulator system ( 1 ) based on the injury information. Method according to claim 10, wherein the calculation of the current position and / or orientation ( 7 ) of the manipulator system ( 1 ) based on an extent of injury of a violation of the first ( 4 ) or the second ( 5 ) Protective field. Method according to one of claims 1 to 11, wherein determining the system position and / or system orientation ( 6 ) of the manipulator system based on odometry and / or radio-based. Manipulator system ( 1 ), comprising in particular a driverless transport vehicle, wherein the manipulator system ( 1 ) a monitoring device ( 2 ), which is set up, a protective field of the manipulator system ( 1 ) and the manipulator system ( 1 ) comprises a control device which is set up, a method according to one of claims 1 to 12 for operating the manipulator system ( 1 ). Method or manipulator system ( 1 ) according to one of claims 1 to 13, wherein the monitoring device laser scanner ( 2 ) for detecting objects in the protective field.

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