DE102018125915A1 - Process for securing a work area of a mobile logistics robot using object marker protective fields - Google Patents

Abstract

The invention relates to a method for protecting a work area (B1, B2) of a mobile logistics robot in changing work environments (A), the logistics robot being controlled by a control system, and the current work environment (A) being detected by and using a sensor system is monitored by a security system. It is proposed that the control system autonomously define an intended work area (B1, B2) in a new work environment (A), and the security system autonomously verify whether at least partial areas of the defined work area (B1, B2) are free or by at least one object (R ) are occupied, and a occupied sub-area is defined as an object marker protective field (OS) that is monitored by the security system for protective field violations, and in the event of a protective field violation due to the object (R) emerging from the object marker protective field (OS), the logistics robot is automatically put into a safe state.

Description

The invention relates to a method for securing a work area of a mobile logistics robot in changing work environments, the logistics robot being controlled by a control system and the current work environment being detected by means of a sensor system and being monitored by a security system.

Robots are increasingly used in industry and in logistics companies to automate processes in industrial production and for logistical tasks, such as picking. Usually robots with arm manipulators, in particular robot arms, are used. An example of this are so-called articulated arm robots.

In today's industrial automation, robotic applications of arm manipulators are usually operated in separate work rooms, which are generally designed as sensor-monitored safety cages. As a current further development, the first collaborative robot concepts in which humans and robots work in the same work environment can be found in the state of the art. For safety reasons, however, the working speed is severely restricted in such robot concepts. The so-called collaborative speed is typically a maximum of 250mm / s. In addition, such robot concepts have very high product costs due to the need for safety-relevant force and moment sensors. In addition, only very low payloads (in the lower kilogram range) can often be lifted, so that an unfavorable payload-to-own-load ratio arises.

The majority of today's robotic solutions can be characterized as a stationary robotic solution, since the robotic arm is either firmly anchored to the floor or is movably mounted on a linear axis. This results in a spatially restricted working space, which is usually separated by a security fence.

There are first mobile approaches with robotic arms on freely mobile platforms. Examples of this are flat autonomous vehicles (AGVs) or driverless industrial trucks, especially mobile order picking robots. As a rule, however, these solutions cannot be used in mixed operation without spatial separation of human operators.

As a modification of permanently installed safety fences, there are first approaches of virtual protective fences, in which the free area around the robot is monitored using suitable sensors (e.g. laser scanners). If the protective field defined by the virtual protective fence is violated, the robot is safely limited or switched off.

The spatial separation of robots and humans creates an inhibiting barrier for the use of collaborative operating concepts with human-robot collaboration. Mixed operation in areas used in parallel by people and robots is often not possible even with mobile robotic units that are mounted on moving platforms, for example. Concepts with application-specific kinematics, in which the avoidance of danger is realized through the shape of the robot housing, severely restrict the scope of the kinematics.

As a result of these obstacles, the known collaborative robot concepts, due to their characteristics, show only very limited fields of application. So far, they have only achieved extremely low market penetration.

The implementation of collaborative concepts for logistics robots, in particular autonomous industrial trucks with robot arms for load handling, e.g. mobile order picking robots, because logistics robots can move freely in a logistics area, e.g. a warehouse. In doing so, they constantly encounter completely new working environments that need to be secured.

The present invention is based on the object of designing a method of the type mentioned at the outset in such a way that safe operation of a mobile, freely movable logistics robot is made possible even in changing work environments in mixed operation with people.

This object is achieved according to the invention in that the control system autonomously defines an intended work area in a new work environment, and the security system autonomously verifies whether at least partial areas of the defined work area are free or occupied by at least one object, and defines an occupied partial area as an object marker protective field is monitored by the security system for protective field violations, and in the event of a protective field violation due to the object emerging from the object marker protective field, the logistics robot is automatically put into a safe state.

The invention is based on the consideration that in the application field of logistics a mobile, freely movable robot works in a work environment that is not largely free Allows mobility of the logistics robot, especially the robot arm, but is very limited due to occupancy by objects in a very small space. This applies, for example, to the loading of material shelves using mobile picking robots. Working in load auxiliary devices, such as shelves, cannot usually be completely covered with today's safety-relevant sensors.

The basic idea of the invention is aimed at also detecting the load support device as part of the working environment and monitoring the load support device for changes in position. Thus, dangers are recognized and can be averted, which result from changes in the location of the load support device, e.g. of a shelf. This is the case, for example, when the load moved by the logistics robot is jammed in the load support device, for example a shelf, and the load support device is thereby moved by the logistics robot.

The working environment is recognized in particular via a non-safe control system and verified by the safety system.

A preferred embodiment of the invention provides that a subarea of the intended work area not occupied by the object is defined as a free protective field and is monitored by the security system, and the logistics robot is automatically in a safe state in the event of a protective field violation due to the object entering the free protective field is transferred.

The sub-areas recognized as free are therefore monitored like classic protective fields for non-occupation. The partial area occupied by the object, for example a shelf, is detected by a further protective field, which is defined as an object marker protective field. In contrast to the free protective fields, this object marker protective field is occupied.

In a particularly preferred development of the invention, the monitoring criterion of the security system is expanded in such a way that all free protective fields must be free (that is, not occupied) and all object marker protective fields must be occupied (that is, occupied).

If the position of the object located in the object marker protective field, for example a roller shelf, changes, this is moved into a free protective field and triggers a protective field violation by this occupation of the free protective field. At the same time, the object is moved out of the object marker protective field and thus triggers a protective field violation if the object marker protective field is not occupied. The displacement of the object is thus recognized in one of the two ways.

In a particularly preferred embodiment of the invention, it is provided that the control system scans the new working environment by means of the sensor system and autonomously defines the intended working area on the basis of the sensor data and transfers a mathematical description of the defined working area to the safety system.

It is also conceivable that the control system is given the definition of the work area by a higher-level logistics management system and the work area is monitored by the robot's own security system.

In both cases, it is advantageous that the electronic control system of the logistics robot itself does not have to be safe. For example, a conventional robot arm control can be used. Security is provided by the security system, which can be designed as a separate electronic security control system.

The non-safe control system expediently scans the working environment with the aid of sensors of the sensor system and defines the intended, safe working area. In particular, a laser scanner can be used as the sensor. The non-safe control system then passes the intended safe work area as a mathematical description (preferably as a polygon) to the safety system, which takes over this definition for its safety sensors, which are preferably designed as scanners. It can also be the same sensors of the sensor system as when the working environment is scanned by the non-safe control system. The security system confirms that the protective field is occupied (i.e. occupied) in the case of an object marker protective field.

A variant of the invention provides that the control system selects the protective field from a predefined set of protective fields that covers the intended work area.

Here, too, the non-safe control system uses sensors to scan the working environment and select the protective field from the predefined set of protective fields that covers the intended, safe working area and suitably fulfills the recognized contour of the intended, safe working area. The non-safe control system then transfers the intended safe working area to the safety system, which takes over this definition for its safety sensors, which are preferably designed as scanners. These can also be the same sensors as when the working environment is scanned by the non-safe control system. The security system confirms that the protective field is occupied (i.e. occupied) in the case of an object marker protective field.

A non-safe control system can also be used for this. The non-safe control system selects the protective field from a predefined set of protective fields which suitably fulfills the recognized contour of the intended work area. The contour of the protective fields can be any. Rectangular protective fields can be assumed without restricting the generality.

With the method according to the invention, a coherent, gap-free protective field can be created and verified, which can be limited by means of a curve (which is preferably predetermined by a polygon). In a further embodiment of the invention, several protective fields are combined. This creates a non-contiguous protective field, which can therefore also have gaps.

A preferred application of the invention provides that a mobile, freely movable robotic vehicle, in particular an autonomous industrial truck, with at least one robot arm is used as a logistics robot for load handling in a changing working environment.

A mobile picking robot is particularly preferably used as the logistics robot.

The invention offers a number of advantages:

Working areas can be developed without a fixed protective field partition. In addition, the working speed can be increased because the robot can be moved at "non-collaborative" speed. In addition, increased payloads can be handled, since no permanent force and torque monitoring of the robot is necessary and thus larger payloads can be moved at increased speed, which are above the monitoring limits. The costs for the sensors can also be reduced, since no collision monitoring by robot-mounted sensors is necessary. Finally, the cost of the robot arm can also be reduced, since standard industrial robots can be used instead of costly collaborative robots. Load handling in "non-free" areas, such as load support devices, is made possible, for example, fixed shelves without floor anchoring, mobile provision systems such as sequence trolleys, portable shelves such as rolling shelves or trolleys.

• 1 eine Kombination aus einem freien Schutzfeld und Objektmarker-Schutzfeldern, und
• 2 die Objektmarker-Schutzfelder im Detail.

Further advantages and details of the invention are explained in more detail with reference to the exemplary embodiments shown in the schematic figures. Show here

• 1 a combination of a free protective field and object marker protective fields, and
• 2nd the object marker protection fields in detail.

In 1 is the protection of a working environment A with a load aid R shown. In the present example, this is a mobile shelf R . In order to ensure safe operation of the mobile, freely moving logistics robot, not shown in the figure, in particular when handling loads by means of a robot arm within the rolling shelf, a protective field verification is carried out with the inclusion of an object marker protective field. For this purpose, a non-safe control system of the logistics robot uses sensors to scan the working environment A and defines the intended, safe work area B1 . As shown in the figure, it becomes a work area B1 chosen that is not of interfering objects P , in this case of pallets P , is occupied. The non-safe control system then transfers the intended safe work area B1 as a mathematical description of a protective field FS (here as a polygon) to a security system of the logistics robot, which adopts this definition for its security sensors, in particular those designed as scanners. The security system confirms that the protective field FS is free (not occupied).

The control system also defines a work area B2 for load handling by means of the robot arm inside the mobile rack R . As shown in the figure, it becomes a work area B2 chosen by a specific object to be monitored R , in this case from the mobile shelf R , is occupied. The non-safe control system then transfers the work area B2 as a mathematical description of an object marker protective field OS to the security system which adopts this definition for its security sensors, in particular those designed as scanners. The security system confirms that the object marker protective field OS is occupied (occupied).

A combined protective field is thus generated, which consists of free protective fields FS and occupied object marker protection fields OS is composed, and to secure the work area B1 , B2 of the mobile logistics robot used in operation within cargo support systems.

The monitoring criterion of the security system provides that all free protective fields FS must be free (i.e. not occupied) and all object marker protective fields OS must be occupied (i.e. occupied).

When the position of the object changes R , in this case the mobile shelf R , this is in a free protective field FS displaced and released by this occupation of the free protective field FS a protective field violation. At the same time, the mobile shelf R from the object marker protection field OS shifted and thus resolved by not occupying the object marker protective field OS a protective field violation. The displacement of the object is thus recognized in one of the two ways.

2nd shows a detailed view of the mobile shelf R and the object marker protection fields OS and the free protective field FS out 1 . In this example, the sensory system of the logistics robot recognizes the roles RR of the mobile shelf R , and the control system defines the immediate environment of the roles RR as object marker protective field OS .

Claims (7)

Method for securing a work area (B1, B2) of a mobile logistics robot in changing work environments (A), the logistics robot being controlled by a control system and the current work environment (A) being detected by means of a sensor system and being monitored by a security system , characterized in that the control system autonomously defines an intended work area (B1, B2) in a new work environment (A), and the security system autonomously verifies whether at least partial areas of the defined work area (B1, B2) are free or by at least one object (R ) are occupied, and a occupied sub-area is defined as an object marker protective field (OS), which is monitored by the security system for protective field violations, and in the event of a protective field violation due to the object (R) emerging from the object marker protective field (OS), the logistics robot is automatically put into a safe state. Procedure according to Claim 1 , characterized in that a portion of the intended work area (B1, B2) not occupied by the object (R) is defined as a free protective field (FS) and is monitored by the security system, and in the event of a protective field violation by entry of the object (R) into the free one Protective field (FS) the robot is automatically set to a safe state. Procedure according to Claim 1 or 2nd , characterized in that the control system scans the new work environment (A) by means of the sensor system and autonomously defines the intended work area (B1, B2) based on the sensor data and transfers a mathematical description of the defined work area (B1, B2) to the safety system. Procedure according to Claim 1 or 2nd , characterized in that the control system selects from a predefined set of protective fields (FS, OS) the protective field (FS, OS) that covers the intended work area (B1, B2). Procedure according to one of the Claims 1 to 4th , characterized in that several protective fields (FS, OS) are combined. Procedure according to one of the Claims 1 to 5 , characterized in that a mobile robotic vehicle, in particular an autonomous industrial truck, with at least one robot arm for load handling in a changing working environment (A) is used as the logistics robot. Procedure according to Claim 6 , characterized in that a mobile picking robot is used as the logistics robot.

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