Collision avoidance methods and means of implementing them

Abstract

A collision avoidance method (400, Fig. 4) including sensing (320, Fig. 3) travel parameters of a vehicle 1, which indicate whether and at what speed the vehicle is travelling forward or reversing; se

Description

Collision avoidance method and means for implementation of such method Description The present invention relates to a collision avoidance method and means for implementation of such a method. Background For the purpose of collision avoidance, vehicles may be configured to carry out collision avoidance methods that may be based on, for example, camera, ultrasonic, radar, or lidar technology. Collision avoidance methods are particularly known from the area of passenger cars. However, they may also be used on mobile work machines, with appropriate adjustments if necessary. Embodiments proposed herein may relate to both areas of use. Overview A collision avoidance method and means for implementation of such are proposed with the features of the independent claims. Advantageous embodiments are the subject matter of the dependent claims as well as the following description. The proposed collision avoidance method includes sensing travel parameters of a vehicle, which indicate whether and at what speed the vehicle is currently going forward or reversing, sensing a travel request for the vehicle, which specifies that the vehicle is to go forward, reverse or be stationary in the future, in particular using an FNR signal (see below for definition), specifying one or more forward-oriented environment sensors or one or more rearward-oriented environment sensors of the vehicle depending on the travel parameters and the travel request, and using the specified sensors to detect objects in an environment around the vehicle. As will be explained in detail below, in particular for vehicles operating using an FNR signal, and in particular during a reversing operation, a direction of travel request and the current direction of movement of the vehicle may not match at the time of a corresponding request. In this state, the system thus no longer reacts to critical objects in the direction of movement. The present invention overcomes this disadvantage and in particular solves the sub-problems discussed below as well. In one embodiment, the collision avoidance method comprises specifying the forward-oriented environment sensor or sensors when at least one of the following conditions is met: (1) The travel request specifies that the vehicle is to go forward in the future and the travel parameters indicate that the vehicle is currently going forward, stationary or reversing at no more than a specified speed, (2) the travel request specifies that the vehicle is to reverse in the future and the travel parameters indicate that the vehicle is currently going forward at more than a specified speed, or (3) the travel request specifies that the vehicle is to remain stationary in the future, and the travel parameters indicate that the vehicle is currently stationary or going forward. Corresponding configurations allow a forward environment of the vehicle to be sensed and collisions to be safely avoided. In one embodiment of the invention, the collision avoidance method comprises specifying the rearward-oriented environment sensor or sensors whenever at least one of the following conditions is met: (1) The travel request specifies that the vehicle is to go forward in the future and the travel parameters indicate that the vehicle is reversing at more than a specified speed, (2) the travel request specifies that the vehicle is to reverse in the future and the travel parameters indicate that the vehicle is reversing, stationary or going forward at less than a specified speed, or (3) the travel request specifies that the vehicle is to remain stationary in the future, and the travel parameters indicate that the vehicle is currently reversing. A corresponding embodiment allows a rear environment of the vehicle to be sensed and collisions to be safely avoided there. In one embodiment of the collision avoidance method, the travel request is specified by a forward neutral reverse (FNR) operator unit by a driver of the vehicle or an autonomous vehicle controller, and / or the vehicle is configured for reversing operation. As already mentioned and further discussed below, specific problems may particularly arise in such vehicles, which are successfully overcome by the embodiments of the present invention. In one embodiment of the invention, the collision avoidance method is carried out in a mobile work machine as the vehicle. Particularly, mobile work machines may be at risk of collisions, for example due to equipment lying in the line of sight, such as buckets, forks, etc., and corresponding collisions may have particularly detrimental effects. Embodiments of the present invention have particular advantages in this case. In embodiments of the proposed collision avoidance method, the forward-oriented environmental sensor or sensors and / or the rearward-oriented environmental sensor or sensors may comprise one or more of the same or different sensors selected from infrared sensors, radar sensors, ultrasonic sensors, camera sensors, and lidar sensors, or combinations thereof. The invention may employ particularly advantageous sensors and / or combinations thereof in corresponding embodiments. The proposed collision avoidance system comprises means for sensing travel parameters of a vehicle, which indicate whether and at what speed the vehicle is going forward or reversing, means for sensing a travel request for the vehicle, which specifies that the vehicle is to go forward, reverse or remain stationary in the future, means for specifying one or more forward-oriented environment sensors or one or more rearward-oriented environment sensors of the vehicle depending on the travel parameters and the travel request, and means for subsequently using the specified sensors to detect objects in an environment around the vehicle. Regarding further features and advantages of a corresponding collision avoidance system and different embodiments thereof, reference is expressly made to the above explanations regarding the proposed collision avoidance method and its embodiments, as they apply in the same way. The proposed computing unit comprises a processor configured to perform the proposed method, in particular according to any of the configurations discussed above and below. These also benefit from the explained advantages of the proposed method and its embodiments. The same also applies to the proposed computer program, which comprises instructions that, when a computer executes the computer program, cause the computer to carry out a collision avoidance method, as previously explained in various embodiments. The proposed computer-readable data carrier with a corresponding computer program stored thereon is substantially the same. The implementation of the proposed method or its embodiments in the form of a computer program or computer program product with program code for carrying out all method steps is particularly advantageous, since this creates particularly low costs, in particular if an executing control device is used for other tasks and is, therefore, already present. Suitable data carriers for providing the computer program are in particular magnetic, optical and electrical memories, such as hard drives, flash memories, EEPROMs, DVDs and others. A download of a program via suitable computer networks (Internet, Intranet, Cloud, etc.) is also possible. Previously described and additional embodiments will be explained further below with reference to the accompanying figures. Figure description Figure 1 illustrates a vehicle having a collision avoidance system. Figures 2A and 2B illustrate basics of embodiments of the invention. Figure 3 shows aspects of a collision avoidance system in a simplified representation. Figure 4 shows a collision avoidance method in a simplified representation. Embodiments The embodiments described below are described solely for the purpose of assisting the reader in understanding the claimed and previously discussed features. They are merely representative examples and are not intended to be exhaustively and / or restrictively considered with respect to the features of proposed embodiments. It is understood that the advantages, embodiments, examples, functions, features, structures, and / or other aspects described above and below are not to be construed as limitations on the scope of the invention as defined in the claims, or as limitations on equivalents to the claims, and that other embodiments may be used and changes made without departing from the scope of the claimed invention. Various embodiments may include, comprise, consist of, or substantially comprise other expedient combinations of the described elements, components, features, parts, steps, means, etc., although such combinations are not specifically described herein. Moreover, the disclosure may include other inventions that are not currently claimed but that may be claimed in the future, particularly if they are encompassed by the scope of the independent claims. Explanations relating to devices, apparatuses, arrangements, systems, etc. according to embodiments proposed herein may also apply to methods, processes, methods, etc. according to the embodiments proposed herein, and vice versa. Identical elements, elements with identical function, or elements with identical or comparable construction, as well as method steps, etc. may be indicated in the drawings with identical reference characters. First, refer to Figure 1, which shows a vehicle 1, in this case a mobile work machine configured in the form of a wheel loader. In the example discussed here, the vehicle 1 is intended to be used for a reversing operation and for providing and / or processing a so-called FNR signal. The FNR signal, where FNR is ‘forward neutral reverse’, is an essential concept, especially in the context of working machines such as excavators, wheel loaders, forklifts, and many other machines used in construction, mining, or agriculture. Different signal states exist to request corresponding operating modes: Forward: In the forward mode, the machine or vehicle 1 operates in the normal working direction. This is typically the main direction of operation of a corresponding vehicle in which, for example, earthmoving, material loading, or similar activities are performed. Stationary or idling (neutral): In the stationary or idle mode, the engine is placed in an inactive state, leaving the machine or vehicle 1 in place but the engine running. This is particularly useful when the operator wants to take a break without turning off the engine or when other functions of the machine are to be operated without movement. Reverse: In the reverse mode, the machine or vehicle 1 may be operated in forward mode, opposite to the normal working direction. This is particularly useful for manoeuvring in confined spaces or for specific tasks that require a direction change, such as reversing a wheel loader after unloading material. In many modern work machines or vehicles 1, corresponding operating modes are provided by the operator via an easy-to-use lever or electronic switch that is not separately illustrated here based on its general familiarity. Some machines are also equipped with additionally configured control systems that enable automatic direction changes based on sensor data or preprogrammed patterns. Switching between these modes quickly and efficiently, particularly in machines deployed in dynamic or confined work environments, may increase productivity and increase safety in corresponding vehicles 1. The reversing operation, often referred to as the reversing function, is an essential feature of many work machines or vehicles 1 and relates to the ability of the machine or vehicle 1 to change its direction of movement or working, particularly without stopping or turning off the engine. For many machines, the reversing operation allows for the shifting between forward and reverse travel or movement. For example, as an example of a vehicle 1, after receiving material, a wheel loader may travel forward to a storage location and then reverse without any delay by activating the reversing mode. In hydraulically operated systems as found in many work machines, the direction of movement of cylinders or engines may be changed by reversing the direction of flow of the hydraulic oil. In electric drive systems, for example in electric motors, the reversing operation may be accomplished by changing the polarity or phase sequence, thereby rotating the motor in the opposite direction. The reversing operation allows corresponding vehicles 1 in particular to manoeuvre efficiently in confined spaces without having to constantly stop and restart. Particularly in scenarios where frequent changes of direction are required, the reversing operation allows for significant time savings and thus an increase in working speed. The reversing operation may also be employed for safety reasons, for example, to quickly get out of a hazardous situation. Examples of applications include, for example, excavators that dig forward and then have to move backwards out of the dig zone. In the area of agricultural machines, a reversing operation may be carried out, for example, on tractors, which must switch between forward and reverse travel during plowing or other field work. Embodiments of the present invention are suitable for any such vehicles 1. Overall, the reversing operation increases the flexibility and versatility of work machines and helps improve their efficiency and safety in a variety of use scenarios. In particular, collisions of vehicles 1 that are configured as mobile work machines pose a significant risk to man and machine. In particular, if vision is limited (e.g., caused by a loaded bucket on a wheel loader or a loaded bed on a dumper), serious accidents may occur. Systems for avoiding or mitigating such collisions are known, and may include, for example, rear view cameras and bird’s eye view cameras for improved visibility, but also collision warning and avoidance systems based on camera, ultrasonic, radar, or lidar technology. These may increase the safety of machine operation as assistance systems. In systems based on environmental sensor technology (e.g., radar), an obstruction (e.g., person, vehicle or wall) is detected by the sensor system. Hydrostatic drive systems are predominantly common in the construction and agricultural machine industries in vehicles 1. In this case, a hydraulic drive pump is fluidly connected to one or more hydrostatic motors in a hydraulic system. The hydraulic fluid provided by the drive pump drives the hydrostatic motors. These motors are also referred to as hydromotors. In particular, for construction machines with hydrostatic drives, the driver provides the direction of travel request via the FNR signal, as already explained in more detail above. During the reversing operation, this results in the direction of travel request and the current direction of movement of the vehicle not matching at the time of a corresponding request. In this state, the system thus no longer reacts to critical objects in the direction of movement. When selecting the sensors to be processed, it is therefore not possible to use purely the FNR signal. An alternative selection of the sensors to be processed as a function of the direction of speed, on the other hand, would result in only one of the two sides (in the forward or reverse direction) being evaluated when stationary, regardless of the driver's direction of travel. Thus, the vehicle would initially allow acceleration while stationary, even if there is a critical object next to it. The selection of the currently relevant sensors must, therefore, be carried out in this case via a combination of the direction of travel request (according to the FNR signal) and the direction of the vehicle speed. There are therefore two sub-problems to solve. (1) While stationary, a response to critical objects in the monitored area must occur on the side corresponding to the direction of travel request, and (2) during motion, a response to critical objects in the monitored area must occur on the side corresponding to the direction of the vehicle speed. Contributions from embodiments of the present invention to solve these issues will be explained in further detail below. First, however, further basics are explained here. In the example presented here, the vehicle 1 has forward-oriented environment sensors 11 and rearward-oriented environment sensors 12, which are respectively illustrated in dashed form and are in no way restricted in terms of their structural configuration. Although only one forward-oriented environment sensor 11 and one rearward-oriented environment sensor 12 are each shown on the vehicle in Figure 1, further sensors may be distributed on the vehicle 1 in any manner and one or more decentralised, distributed or central evaluation units may be provided. In particular, a detection arrangement formed accordingly may have video, radar, lidar, ultrasonic, or infrared sensors of any type, combination and circuitry as forward-oriented environment sensors 11 and rearward-oriented environment sensors 12, and / or may be configured to communicate with other vehicles. In the illustrated example, the forward-oriented environment sensor or sensors 11 are directed to a forward environment, shown smaller in size and designated schematically with 2, and the rearward-oriented environment sensor or sensors 12 are directed to a rear environment, shown smaller in size and designated schematically with 3, to detect an object 21 and 31, respectively. A corresponding detection arrangement, part of which may in particular be a controller 15, may in particular be configured to assign objects 21 and 31, respectively, to object classes. In this way, object 21 or 31 may be detected as, for example, a less critical object 21 or 31, for example, an inanimate object 21 or 31, or as a more critical object 21 or 31, for example, a human being. In this context, a ‘collision-relevant’ object 21 or 31 may be referred to, which may differ from another, i.e., in particular a non-collision-relevant object, already due to the fact that it is located in forward or rear environment 2 or 3. A collision-relevant object 21 or 31 may differ from another object in that a collision with it results in undesirable effects, for example damage to vehicle 1 or object 21 or 31, respectively. For example, a non-collision relevant object may be characterised by being too small or having a material that does not allow negative effects to be expected in a collision. Examples of noncollision relevant objects include, for example, gravel, foliage, sand or paper in the roadway. For example, an object 21 or 31 may be designated as a collision-relevant object 21 or 31 by a user definition or specification, i.e., classified accordingly. The detection of collision-relevant or less critical objects 21 and 31, respectively, may be carried out with different sensor systems, depending on the detection. Depending on whether an object 21 or 31 may be detected by radar, lidar or video sensors 11 or 12, or from a combination thereof, objects 21 or 31 may be associated with the object classes. The assignment of objects 21 and 31 to corresponding object classes may advantageously be carried out as a function of measurement data of one or more sensors on the basis of the object extension measured by lidar and / or radar sensors or on the basis of the grey value pattern determined by video sensors. For example, a pedestrian is more likely to be detectable by a video sensor, whereas a radar sensor may allow for more unreliable detection. The assignment of the objects 21 and 31 to corresponding object classes may be performed as a function of object speed. By means of such an object classification, the detected objects 21 or 31 may be classified as standing, stopped, slow-moving or fast-moving objects 21 or 31, for example. Due to this assignment, it is possible to predict an estimate of the future maximum possible acceleration of the objects as well as acceleration directions. Known collision avoidance systems, which may be implemented, for example, using controller 15 of the vehicle 1, may estimate or determine a time to collision (TTC) based on the transmitted distance to object 21 or 31 and its relative speed, as well as estimate or determine a distance, for which a warning is given when such distance is undercut (there is still enough time for the driver to manually engage the brakes) or a distance, for which a braking or deceleration action is automatically engaged when such distance is undercut. Such systems are already known from the automotive field and are also used in the field of mobile work machines with corresponding adjustments. Embodiments of the present invention solve the aforementioned problems with the proposed collision avoidance method or system. These problems, and the solution according to aspects of the invention, will again be explained with reference to Figures 2A and 2B, where a vehicle 1 in the form of a wheel loader and an object 31 in a rear environment are shown. A direction of travel is indicated in Figure 2A with an arrow 13, and a direction specification by an FNR signal with an arrow 14. It is understood that configurations of the present invention may include further situations not illustrated in Figures 2A and 2B. In the situation illustrated in Figure 2A, the vehicle 1 is reversing, and the object 31 would therefore subsequently collide with the vehicle 1. However, the FNR signal specifies forward travel so that the collision after reversing is no longer relevant. Therefore, in embodiments of the invention, forward-oriented sensors 11 are now selected here if the further conditions discussed below are met. In the situation illustrated in Figure 2B, the vehicle is stationary. The vehicle therefore cannot collide with the object 31 if it continues to be stationary. However, the FNR signal specifies reverse travel so that the collision risk becomes acute after starting to move. Therefore, in embodiments of the invention, rearward-oriented sensors 12 are now selected here, in particular if the further conditions discussed below are met. Table 1 shows the respective procedure, where a speed threshold of forward travel is indicated with v_Thd and a speed threshold of reverse travel is indicated with -v_Thd. An unsigned speed denotes a forward travel speed, a negative-signed speed denotes a reverse travel speed. If the unsigned speed v is therefore above the speed threshold of the forward travel v_Thd, then the vehicle is going forward; if it is below it, including into the negative range, the vehicle may still be going forward, but may also be stationary or reversing. If the speed v or -v, which is then in the negative range, is below the speed threshold of the reverse travel -v_Thd, the vehicle is reversing; it if is above it, the vehicle may still be reversing, but may also be stationary or going forward. stDrvDirDem is used to indicate the specification of the FNR signal, where -1 is requested reverse travel, 1 is requested forward travel, and 0 is requested neutral. As mentioned, the signal may be provided via a control unit by a user or in any other manner. The used forward- or rearward-oriented sensors are 11 and 12, respectively, as indicated in Figure 1. Table 1 stDrvDirDem -1 stDrvDirDem 0 stDrvDirDem 1 v >v_Thd 11 v >0 11 v >-v_Thd 11 v <v_Thd 12 v<0 12 v <-v_Thd 12 Embodiments of the proposed collision avoidance method include sensing travel parameters of a vehicle 1 that indicate whether and at what speed the vehicle is going forward or reversing, i.e., a speed v without or with a negative sign or the value zero. Likewise, sensing a travel request for the vehicle 1 that specifies that the vehicle 1 is to go forward, reverse, or be stationary in the future is expressed in Table 1 with a corresponding value for the parameter stDrvDirDem of -1, 0, or 1. Based on this, one or more forward-oriented environment sensors 11 or one or more rearward-oriented environment sensors 11 are provided and are subsequently used to detect objects 21 and 31 in the environment of the vehicle 1. More specifically, the specification of the or forward-oriented environment sensor or sensors 11 in embodiments of the present invention always occurs when at least one of the following conditions 1 to 3 is met: 1. The travel request dictates that the vehicle 1 is to go forward in the future and the driving parameters indicate that the vehicle 1 is going forward, stationary, or reversing at no more than a specified speed, i.e., stDrvDirDem >0, and v >-v_Thd according to table columns 5 and 6, penultimate row of table 1. 2. The travel request specifies that the vehicle 1 is to reverse in the future and the travel parameters indicate that the vehicle 1 is going forward at more than a specified speed, i.e., stDrvDirDem <0 and v >v_Thd according to table columns 1 and 2, penultimate line of Table 1. 3. The travel request specifies that the vehicle 1 is to be stationary in the future, and the travel parameters indicate that the vehicle 1 is stationary or going forward, i.e., stDrvDirDem = 0 and v >0 according to table columns 3 and 4, penultimate line of Table 1. Specification of the rearward-oriented environment sensor or sensors 12 in embodiments of the present invention when at least one of the following conditions 3 to 5 is met, whereby the numbering is for distinguishing purposes only: 4. The travel request specifies that the vehicle 1 is to go forward in the future and the travel parameters indicate that the vehicle 1 is reversing at more than a specified speed, i.e., stDrvDirDem >0 and v <-v_Thd according to table columns 5 and 6, last line of Table 1. 5. The travel request specifies that the vehicle 1 is to reverse in the future and the travel parameters indicate that the vehicle 1 is reversing, stationary or going forward at less than a specified speed, i.e., stDrvDirDem <0 and v <v_Thd according to table columns 1 and 2, last line of Table 1. 6. The travel request specifies that the vehicle 1 is to be stationary in the future, and the travel parameters indicate that the vehicle 1 is reversing, i.e., stDrvDirDem = 0, and v <0 according to table columns 3 and 4, last row of table 1. Thus, with embodiments of the invention, a response may be provided to critical objects in the monitored area on the side corresponding to the direction of vehicle speed while in motion. When reversing, the selection of sensors 11 or 12 allows a response to an object 21 or 31 in critical area 2 or 3. If stationary, a corresponding selection of sensors 11 or 12 allows a response to an object 21 or 31 in critical area 2 or 3 after starting to move. In Figure 3, a method according to one embodiment is illustrated and is designated as 300 overall. Initially, designated as 310, the vehicle is traveling or is stationary without recording an FNR request. In a step 320, there is sensing 320 of travel parameters of a vehicle 1, which indicate whether and at what speed the vehicle (1) is going forward or reversing. In a step 330, sensing 330 of a travel request for the vehicle 1 occurs, which specifies that the vehicle 1 is to go forward, reverse or be stationary in the future, i.e., an FNR signal. Steps 320 and 330 may be swapped or performed in parallel. A step 340 comprises selecting one or more forward-oriented environment sensors 11 or one or more rearward-oriented environment sensors 11 of the vehicle 1 depending on the travel parameters sensed in steps 320 and 330, respectively, and the travel request. In step 350, there is subsequent use of the specified sensors 11 or 12 for detecting objects 21 or 31 in a forward or rear environment 2 or 3 of the vehicle 1, as explained above. With embodiments of the present invention, the availability of the collision avoidance system may be increased, in particular during the reversing operation. Furthermore, this may allow for a reduction of collisions, in particular during the reversing operation. Early validation of critical objects while stationary is made possible by taking into account the direction of travel request. Embodiments of the present invention may be implemented with the existing information in a corresponding vehicle without any further sensor technology, for which case reference is particularly made to Figure 4, illustrating aspects of a collision avoidance system in a simplified representation in the form of a not specifically marked block diagram. As illustrated with 411, a parameterisation 410 provides suitable parameters such as the mentioned speed threshold values v_Thd and -v_Thd, respectively. By means of a signal provision 420, for example via a CAN bus, signals or values 421 and 422, respectively, are provided and sensed accordingly, which signals or values represent the mentioned travel 5 parameters of vehicle 1 indicating whether and at what speed the vehicle 1 is going forward or reversing, and the travel request for the vehicle 1 specifying that the vehicle 1 is to go forward, reverse, or be stationary in the future. A sensor selection 430 is made on this basis in embodiments of the present invention in the 10 manner already mentioned several times, wherein a corresponding selection or specification signal 431 may be output.

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