Sensor module for a mobile robot system, mobile robot system having a sensor module of this type, and method for operating the sensor module

Abstract

A sensor module (SM) for a mobile robot system (R) is designed to be portable. The sensor module (SM) comprises one or more connection points (A1, A2), by means of which the sensor module (SM) can be mounted both on the mobile robot system (R) and on an object (T) to be transported by the mobile robot system. The sensor module (SM) also comprises at least one sensor (S), by means of which the environment of the mobile robot system is sensed, and the evaluation of the sensor data thus produced allows the position of the sensor module (SM) relative to the mobile robot system to be determined and / or a change in the relative position to be determined.

Description

[0001] Description

[0002] Sensor module for a mobile robot system, mobile robot system with such a sensor module and method for operating the sensor module

[0003] The present invention relates to a sensor module for a mobile robot system and to a mobile robot system with such a sensor module, which can be provided in particular for object transport. The present invention further relates to a method for operating the sensor module.

[0004] There are a wide variety of application areas for autonomous mobile robots. For example, in the field of logistics, there are various concepts for self-driving transport robots that enable the independent delivery of goods to a predetermined destination, be it in a logistics or production hall or even to the end consumer. A mobile robot system with a mobility platform for transporting interchangeable modules is disclosed, for example, in DE 102017210 584 A1. The robot system described therein comprises a mobility platform for transporting interchangeable modules, in which an electropermanent magnet is provided for coupling the mobility platform to an interchangeable module. There are also concepts for parking robots with a platform for transporting vehicles, in which the driver and passengers leave the vehicle at the entrance of a parking garage and hand it over to the parking robot.The parking robot then moves to a free parking space where it unloads the vehicle.

[0005] For such transport tasks, precise path planning of the autonomous mobile robot is of fundamental importance. This, in turn, requires the most precise possible recording of the current environment of the autonomous mobile robot, as this is the only way for the robot to navigate through its surroundings, detect obstacles, and avoid collisions with these obstacles. For this purpose, the autonomous mobile robots can be equipped with various sensors for environment detection, such as one or more CMOS or CCD cameras, lidar, radar, and / or ultrasonic sensors. One or more of these sensors can then be arranged in a common sensor module, which can also have a computing unit for processing the recorded sensor data. Such a sensor module can be permanently mounted on the respective robot and supplied with electrical power via a stationary power connection.

[0006] It is an object of the invention to provide an improved sensor module for a mobile robot system, a mobile robot system with such a sensor module and a method for operating such a sensor module.

[0007] This object is achieved by a sensor module for a mobile robot system having the features of claim 1, a mobile robot system having the features of claim 14, and a method having the features of claim 15. Preferred embodiments of the invention are the subject of the dependent claims.

[0008] The invention is based on the realization that the detection range of a sensor module for environment detection during a transport task of a mobile robot system can be impaired by the object to be transported. For example, the object to be transported can be located in front of an environment camera of the mobile robot in such a way that the environment behind the object to be transported is partially or completely obscured. Although attempts can be made to prevent this from happening by appropriately arranging the sensors on the autonomous mobile robot, based on the known object shapes of the transported objects, this will not always be possible and thus limits the potential applications of the autonomous mobile robot.Furthermore, even after the autonomous mobile robot has been placed on the market, new, unexpected object designs and sizes of the transported objects may arise, which could lead to impairment of the sensors. This could result in the autonomous mobile robot's navigation and thus safe autonomous travel being impossible or having to be aborted.

[0009] These disadvantages can be avoided in the sensor module according to the invention for a mobile robot system in that it is designed to be portable and comprises the following components: one or more connections by means of which the sensor module can be mounted both on the mobile robot system and on an object to be transported by the mobile robot system; and at least one sensor by means of which the environment of the mobile robot system is detected, wherein the evaluation of the sensor data generated thereby enables the determination of the relative position of the sensor module with respect to the mobile robot system and / or the determination of a change in the relative position.

[0010] In this way, the arrangement of the sensor module can be dynamically adapted to the geometry of the transported object without any noticeable effort. The application area of ​​an autonomous mobile robot equipped with such a sensor module is thus hardly limited by the object to be transported, thus offering greater flexibility for object transport.

[0011] According to a first embodiment, the sensor module is configured to acquire first data with the at least one sensor when the sensor module is in a first position; to acquire second data with the at least one sensor when the sensor module is in a second position after repositioning; and to supply the first and second data to an evaluation for determining the relative position and / or change in the relative position.

[0012] An advantage of this embodiment is that it is particularly easy to implement, since one or more image sensors are already present to detect the environment.

[0013] According to a second embodiment, the sensor module is configured with at least one inertial sensor to acquire inertial sensor data as soon as the sensor module mounted on the mobile robot system or the object to be transported is dismantled; to acquire when the sensor module has been repositioned; to stop the acquisition of the inertial sensor data; to determine the movement path of the sensor module from the acquired inertial sensor data; and to supply the position of the sensor module before dismantling and the determined movement path to an evaluation for determining the relative position and / or change in the relative position.

[0014] This enables position detection even when, for example, detection using imaging methods is difficult or disrupted due to environmental conditions, or when no suitable structure can be identified in the environment that can be evaluated to detect a change in position. According to a third embodiment, the sensor module is configured to detect when the sensor module has been repositioned; to acquire sensor data using the at least one sensor; and to feed the acquired sensor data to an evaluation to determine the relative position and / or change in the relative position, in which the acquired sensor data is compared with data from a previously generated digital map of the environment of the mobile robot system.

[0015] In this way, for example, a position can be determined even if the surroundings have not been detected before the sensor module is repositioned.

[0016] Preferably, detection is carried out when a connection of the sensor module is detached from the mobile robot system or the object to be transported, or when a previously detached connection is connected to the object to be transported or the mobile robot system after repositioning; and the acquisition of the sensor data is controlled depending thereon.

[0017] Advantageously, the sensor module comprises a communication unit for wireless communication with the mobile robot system. This ensures that the sensor data can be transmitted instantly even when the sensor module is not connected to the mobile robot system.

[0018] According to one embodiment of the invention, the sensor module comprises an evaluation unit with which the evaluation of the sensor data takes place, wherein the new position of the sensor module determined by the evaluation unit is then transmitted to the mobile robot system by means of the communication unit.

[0019] According to a further embodiment of the invention, the acquired sensor data are transmitted to the mobile robot system by means of the communication unit and then evaluated by an evaluation unit of the mobile robot system.

[0020] The sensor module preferably comprises a camera and / or a LiDAR sensor and / or a radar sensor and / or an ultrasonic sensor for detecting the surroundings of the mobile robot system. Likewise, the sensor module can advantageously comprise a compass sensor for detecting the mounting angle.

[0021] Furthermore, the sensor module can advantageously additionally comprise one or more of the following components: a battery unit for supplying power to the sensor module when the sensor module is not mounted on the mobile robot system; an adjustment unit for fine positioning and / or fine alignment of the sensor module.

[0022] According to one embodiment of the invention, the sensor module is provided with a first connection by means of which the sensor module can be mounted to the mobile robot system and a second connection by means of which the sensor module can be mounted to an object to be transported.

[0023] In this case, the first connection advantageously additionally has an electrical contact for a battery unit of the sensor module and / or for data transmission.

[0024] The invention also includes a mobile robot system comprising a portable sensor module according to one of the preceding claims and a navigation unit for autonomous navigation, wherein the determined relative position of the sensor module with respect to the mobile robot system and / or the change in the relative position is taken into account in the navigation unit when determining the position of the mobile robot system.

[0025] Furthermore, the invention also includes a method for operating a portable sensor module, wherein the environment of the mobile robot system is detected by means of at least one sensor of the portable sensor module and the evaluation of the sensor data generated thereby enables the determination of the relative position of the sensor module with respect to the mobile robot system and / or a change in the relative position.

[0026] Finally, the invention also includes a computer program with instructions for carrying out the steps of the method according to the invention.

[0027] Further features of the present invention will become apparent from the following description and claims in conjunction with the figures. Fig. 1 shows a portable sensor module according to the invention, mounted on a mobile robot system or on a transport object (B) located on the mobile robot system;

[0028] Fig. 2 shows schematically the component structure of a sensor module according to the invention;

[0029] Fig. 3 shows schematically, for a first embodiment, the position determination of the sensor module (A) and the method steps (B) carried out for this purpose;

[0030] Fig. 4 shows schematically, for a second embodiment, the position determination of the sensor module (A) and the method steps (B) carried out for this purpose;

[0031] Fig. 5 shows schematically for a third embodiment the position determination of the sensor module (A) as well as method steps (B) carried out for this purpose.

[0032] Fig. 6 shows schematically the joint operating principle of a mobile robot system and sensor module when mounted on the mobile robot system;

[0033] Fig. 7 shows schematically the joint operating principle of a mobile robot system and sensor module when mounted on an object; and

[0034] Fig. 8 shows different mounting positions of the sensor module on the mobile robot system (A), as well as two examples of a mobile robot system with multiple sensor modules (B).

[0035] To better understand the principles of the present invention, embodiments of the invention are explained in more detail below with reference to the figures. It is understood that the invention is not limited to these embodiments and that the described features may also be combined or modified without departing from the scope of the invention as defined in the claims.

[0036] Figure 1 shows a mobile robot system R with a portable sensor module SM according to the invention. The sensor module SM contains various components, in particular one or more environmental sensors for detecting the environment of the mobile robot system, of which only one sensor S is shown as an example in the figure for the sake of clarity. The environmental sensors are used in particular for obstacle detection in order to be able to adapt the travel route of the mobile robot system or to stop the mobile robot system in the event of an impending collision. The obstacles can be, for example, objects, buildings, or other mobile robot systems located on the travel route. Likewise, curbs or larger uneven surfaces can be detected and, if necessary, overcome in combination with an active chassis.

[0037] In Figure 1A, the sensor module is mechanically and electrically connected to the mobile robot system R by means of a connection unit A1. This connection is designed in such a way that, on the one hand, it enables easy assembly, but on the other hand, it ensures that the sensor module can be securely mounted both on the mobile robot system R and on the object to be transported. Furthermore, electronic contacts are provided by means of which the sensor module can be connected to a battery RB of the mobile robot system in order to charge a battery in the sensor module via this contact. An electrical connection for data transmission is also provided, by means of which, for example, sensor data can be transmitted from the sensor module to a processing unit RR of the mobile robot system.

[0038] Furthermore, the computing unit RR is configured to control the active chassis of the mobile robot system depending on the recorded sensor data on the mobile robot system's environment and the information on the travel route. In the example shown, the mobile robot system has wheels that can be driven by DC motors, for example. Preferably, all four wheels are driven individually, but it is also possible for only some of the wheels to be driven. Likewise, all or just some of the wheels can be steered in order to be able to adjust the direction of travel. Instead of four wheels, a larger number of wheels or a drive with chains or legs can be provided, which can be particularly advantageous if the mobility platform must be able to overcome curbs, steps or larger uneven ground.

[0039] Furthermore, the mobile robot system R has, among other things, a navigation unit (not shown), which calculates the route to be covered by the mobile robot system based on electronic maps and position information supplied, for example, by an integrated GPS receiver. Figure 1B shows the mobile robot system R with a transport object T located thereon, schematically represented by several barrels located on a transport pallet. In this case, the area provided for receiving the sensor module in the mobile robot system is shielded by the transport pallet to such an extent that the sensor module can no longer be operated correctly. For this reason, according to the invention, the sensor module is now dismantled from the mobile robot system before the transport pallet is positioned on the mobile robot system.A suitable connection unit A2 can now be mounted on a transport object, in this case on the foremost barrel in the direction of travel, so that the surroundings of the mobile robot system can again be accurately detected by the sensor module SM. The connection unit A2 is designed to allow mounting on any surface; however, electrical contacts are not required in the connection unit A2. This allows the sensor module to be powered by a battery unit integrated into the sensor module while it is on the transport object. In this case, data transmission to the mobile robot system can be carried out via wireless communication, for example, via Bluetooth, WLAN, or mobile radio.

[0040] Figure 2 schematically shows the component structure of a sensor module according to the invention. Some of the components shown are merely optional, but the sensor module may also contain additional components not shown.

[0041] The sensor module SM comprises, in particular, the sensor system S with one or more sensors for detecting the environment of the mobile robot system. Various sensor types can be considered for this purpose. Optical methods can be used that are based on image capture by cameras in the visible or infrared spectral range. In addition to mono, stereo cameras can also be used, which also provide depth information. Likewise, TOF cameras with a time-of-flight method, in which the time it takes for the light of a light pulse to reach the object and back again is measured for each pixel, allow the distance of the object depicted on it to be determined for each pixel. Image capture by means of a camera also enables the detection of the detected objects, if necessary using image analysis and image recognition methods.Furthermore, a relevant area can be scanned with a laser beam or scanned with a lidar method. Radar sensors, which emit a radar wave and evaluate the echo, are also well suited. Finally, the use of acoustic methods based on ultrasonic waves is also possible. If multiple sensors are used simultaneously in the sensor module, these can also be based on different methods. Depending on the design, the sensor module can also contain an inertial sensor for detecting the movement of the sensor module and a compass sensor.

[0042] The sensor module also includes a processing unit (SR), which may, for example, have a microprocessor, an electronic memory, and one or more electrical interfaces. In particular, the processing unit (SR) can also implement an evaluation unit with which the acquired sensor data can be processed. A communication unit (K) enables data exchange between the sensor module and the mobile robot system. Communication can be wired if the sensor module is mounted on the mobile robot system; however, wireless communication is required if the sensor module is mounted on the transport object.

[0043] The sensor module also includes a battery unit (SB) for independent power supply when the sensor module is mounted on the transport object. This battery unit can be charged via electrical contacts as long as the sensor module is mounted on the mobile robot system. A separate charger can also be provided for this purpose.

[0044] The sensor module also features the aforementioned connection units A1 and A2. Connection unit A1 is intended for mounting on the mobile robot system, while connection unit A2 is intended for mounting on a transport object. However, it is also conceivable to integrate both connection units A1 and A2 into a single connection unit.

[0045] An optional adjustment unit J can be provided for fine positioning and / or fine alignment of the sensor module. Finally, the sensor module can be provided with a display unit A, for example, using one or more LEDs or an LCD display, with which status messages can be output to a user of the mobile robot system.

[0046] For path planning and navigation, a transformation between a coordinate system of the mobile robot system and the coordinate system of the sensor module is required to determine the position of the sensor module relative to the mobile robot system. This transformation must be updated or recalibrated after the sensor module is repositioned. Three different embodiments are explained in Figures 3 to 5.

[0047] In a first embodiment, as schematically shown in Figure 3A, two data sets on the robot's environment are acquired and directly compared using the sensor module. The data sets can contain a wide variety of data that appropriately reflect the robot's environment. The following example assumes image data that is acquired, for example, with a conventional camera. However, image data from an ultrasonic or radar sensor or even two lidar scans (2D or 3D) can also be acquired in order to determine the change in position using a registration process. This occurs both when the sensor module is mounted on the robot and when the sensor module is located on a transport object, which is not shown in Figure 3A for reasons of clarity. The following method steps, shown in Figure 3B, take place in detail.

[0048] First, in a step 31, image data for an area B is acquired by a sensor integrated in the sensor module, for example a camera. This can be initiated by a user of the mobile robot system. For example, a user of the mobile robot system can give an operating command to acquire the image data using a manual control element or voice input. However, the acquisition can also occur automatically if it is detected that the connection of the sensor module is released in order to reposition the sensor module. In step 32, it is then detected when the sensor module is in a second position after repositioning. This can also be a manual input from the user or it can be detected automatically when the sensor module is mounted with one of the connections on the object to be transported or on the mobile robot system after repositioning.

[0049] In step 33, image data for area B is then acquired again using the same sensor at the new position of the sensor module. The image data acquired in the original position and the new position are then compared in step 34 to determine the relative position and / or change in the relative position. In the following step 35, the new position of the sensor module is determined based on this. This uses a predefined fixed coordinate system K1 of the mobile robot system and the coordinate system K2 defined by the position of the sensor module when mounted on the mobile robot system. By evaluating the image data, the position of the coordinate system K3 of the sensor module at the new position can be determined in relation to the original position of the sensor module, which then results in the position of this coordinate system K3 in relation to the coordinate system K1 of the mobile robot system.In step 36, the new position is transferred to the mobile robot system and is then available for path planning and navigation.

[0050] In a second embodiment, as shown schematically in Figure 4A, a movement path of the sensor module is determined to determine the change in position.

[0051] An inertial sensor integrated into the sensor module is particularly suitable for this purpose. According to the method in Figure 4B, this inertial sensor data is continuously acquired in step 41 as soon as the sensor module mounted on the mobile robot system or the object to be transported is removed. In step 42, corresponding to step 32 in the first embodiment, it is then detected when the sensor module has been repositioned, and in step 43, the acquisition of the inertial sensor data is terminated. Subsequently, in step 44, the movement path of the sensor module and, from this, the current position of the sensor module are determined from the acquired inertial sensor data. This data is then transmitted to the mobile robot system and updated there in step 45.The determination of the movement path of the sensor module can also be carried out in other ways instead of using an inertial sensor, for example by continuously recording and evaluating image data from a camera or other suitable sensor.

[0052] In a third embodiment, as shown schematically in Figure 5A, sensor data acquired with the sensor module are compared with data from a previously generated digital map of the environment of the mobile robot system to determine the change in position.

[0053] According to the method in Figure 5B, in a step 51 an initial 3D map of the surroundings of the mobile robot system is first recorded and saved so that it can be used later to determine the current position of the sensor module. After it has been recorded in step 52 that the sensor module has been repositioned, the current surroundings of the mobile robot system are recorded using a sensor of the sensor module in step 53. Subsequently, in step 54 the currently recorded sensor data are compared with the data present in the 3D map in order to determine the transformation of the coordinate system of the sensor module and thus its new position on this basis in the following step 55. This is then transmitted to the mobile robot system in step 56 and updated there.Although the embodiments illustrated in Figures 3 to 5 have been described separately, a combination of the described methods can also be provided. For example, position determination based on comparison with a digital map can be combined with the use of inertial sensor data.

[0054] Figures 6 and 7 schematically show the functional principle for the overall system formed by the mobile robot system and the portable sensor module. The individual components of the sensor module SM correspond to the components shown in Figure 2; of the mobile robot, only the battery unit RB and the computing unit RR are shown, as in Figure 1A. In the illustrations, charging processes are indicated by a dashed line (—), the power supply to the components by a solid line (- —), and the data exchange between different components by a dotted line (■ ■ ■ ).

[0055] Figure 6 schematically shows the functional principle when the sensor module SM is mounted on the mobile robot system R. The battery SB of the sensor module is charged via the connection unit A1 using the battery unit RB of the mobile robot system. Data exchange between the computing unit RR of the mobile robot system and the computing unit SR of the sensor module is also enabled via the connection A1. The computing unit of the sensor module can then, in particular, control the sensors and receive data from the sensors. The computing unit of the sensor module can also exchange data with other components of the sensor module; data output via the display unit A is indicated here as an example. The battery of the sensor module supplies the other components of the sensor module, whereby the example shown assumes a purely mechanical adjustment unit J that does not require any power supply.

[0056] Figure 7 schematically shows the functional principle when the sensor module SM is mounted on a transport object T via connection unit A2. The power supply for the individual components of the sensor module continues to be provided by the sensor module's battery SB, although the battery can no longer be charged via connection unit A1 from the mobile robot system's battery unit RB. Likewise, data exchange between the computing unit of the mobile robot system RR and the computing unit of the sensor module SR can no longer take place via connection A1, but instead occurs wirelessly via the sensor module's communication unit K. The sensor module can be mounted in various areas of the mobile robot system. This is shown schematically in Figure 8A using eight possible positions.Furthermore, even if only one sensor module according to the invention was used in the above embodiments, several such portable sensor modules SM1, SM2, SM3 can also be mounted simultaneously on the mobile robot system and used together, as shown in Figure 8B. One or more of these sensor modules can then be removed from the mobile robot system and mounted on one or more transport objects, as described above.

[0057] Furthermore, the sensor module according to the invention is used in the illustrated examples for a mobile robot system with transport tasks, but is not limited to this, but can also be used for mobile robot systems with other areas of application, such as in the field of inspection, cleaning or service robotics.

[0058] List of reference symbols

[0059] R Mobile Robot System

[0060] RR computing unit of the mobile robot system

[0061] RB battery of the mobile robot system

[0062] SM, SM1, SM2, SM3 sensor module

[0063] S Sensor

[0064] A1, A2 connection unit

[0065] A display unit

[0066] K Communication unit

[0067] SR computing unit of the sensor module

[0068] J Adjustment unit

[0069] SB sensor module battery

[0070] B detected area of ​​the robot environment

[0071] 31 - 36 Process steps first embodiment of the position determination of the sensor module

[0072] 41 - 45 Process steps second embodiment of the position determination of the sensor module

[0073] 51 - 56 Process steps third embodiment of the position determination of the sensor module

Claims

Patent claims Sensor module (SM) for a mobile robot system (R), which is designed to be portable and comprises the following components: one or more connections (A1, A2), by means of which the sensor module (SM) can be mounted both on the mobile robot system (R) and on an object (T) to be transported by the mobile robot system; and at least one sensor (S), by means of which the environment of the mobile robot system is detected, wherein the evaluation of the sensor data generated thereby enables the determination of the relative position of the sensor module (SM) in relation to the mobile robot system and / or the determination of a change in the relative position.Sensor module according to claim 1, which is configured to acquire first data (31) with the at least one sensor (S) when the sensor module (SM) is in a first position; to acquire second data (33) with the at least one sensor (S) when the sensor module (SM) is in a second position after repositioning; and to supply the first and second data to an evaluation for determining (35) the relative position and / or change in the relative position.Sensor module according to claim 1, which is configured to acquire inertial sensor data (41) with at least one inertial sensor as soon as the sensor module (SM) mounted on the mobile robot system or the object to be transported is dismantled; to acquire when the sensor module (SM) has been repositioned (42); to stop the acquisition of the inertial sensor data (43); to determine the movement path of the sensor module (SM) from the acquired inertial sensor data (44); and to supply the position of the sensor module (SM) before dismantling and the determined movement path to an evaluation for determining the relative position and / or change in the relative position. Sensor module according to claim 1, which is configured to detect (52) when the sensor module (SM) has been repositioned; to detect (53) sensor data with the at least one sensor (S); and to supply the detected sensor data to an evaluation for determining the relative position and / or change in the relative position, in which the detected sensor data are compared (54) with data from a previously generated digital map of the surroundings of the mobile robot system. Sensor module according to one of the preceding claims, wherein detection takes place when a connection (A1, A2) of the sensor module (SM) is detached from the mobile robot system (R) or the object (T) to be transported, or a previously detached connection is connected to the object (T) to be transported or the mobile robot system (R) after repositioning; and the detection of the sensor data is controlled depending thereon.Sensor module according to one of the preceding claims, which comprises a communication unit (K) for wireless communication with the mobile robot system. Sensor module according to one of the preceding claims, which comprises an evaluation unit with which the evaluation of the sensor data takes place, wherein the new position of the sensor module determined with the evaluation unit is transmitted to the mobile robot system by means of the communication unit (K). Sensor module according to one of claims 1 to 6, wherein the recorded sensor data is transmitted to the mobile robot system (R) by means of the communication unit (K) and evaluated by an evaluation unit of the mobile robot system. Sensor module according to one of the preceding claims, wherein it comprises a camera and / or a LiDAR sensor and / or a radar sensor and / or an ultrasonic sensor for detecting the environment of the mobile robot system.Sensor module according to one of the preceding claims, wherein it comprises a compass sensor for detecting the mounting angle. Sensor module according to one of the preceding claims, wherein it additionally comprises one or more of the following components: a battery unit for supplying power to the sensor module when the sensor module is not mounted on the mobile robot system; an adjustment unit (J) for fine positioning and / or fine alignment of the sensor module. Sensor module according to one of the preceding claims, wherein a first connection (A1), by means of which the sensor module can be mounted on the mobile robot system, and a second connection (A2), by means of which the sensor module can be mounted on an object to be transported, are provided. Sensor module according to claim 12, wherein the first connection (A1) additionally has an electrical contact for a battery unit of the sensor module and / or for data transmission.A mobile robot system (R) comprising a portable sensor module (SM) according to one of the preceding claims and a navigation unit for autonomous navigation, wherein the determined relative position of the sensor module with respect to the mobile robot system and / or the change in the relative position is taken into account in the navigation unit when determining the position of the mobile robot system. A method for operating a portable sensor module, wherein the environment of the mobile robot system is detected by means of at least one sensor of the portable sensor module, and the evaluation of the sensor data generated thereby enables the determination of the relative position of the sensor module with respect to the mobile robot system and / or a change in the relative position.

Images