Patent Publication Number: US-2021188355-A1

Title: Transverse steering method and transverse steering device for moving a vehicle into a target position, and vehicle for this purpose

Description:
CROSS-REFERENCE TO PRIOR APPLICATIONS 
     This application is a continuation of International Patent Application No. PCT/EP2019/071662, filed on Aug. 13, 2019, which claims priority to German Patent Application No. DE 10 2018 122 055.3, filed on Sep. 10, 2018. The entire disclosure of both applications is incorporated by reference herein. 
    
    
     FIELD 
     The present disclosure relates to a transverse steering method and a transverse steering device for moving a driven vehicle to a target position with a target location and a target orientation, as well as a vehicle set up for this purpose. 
     BACKGROUND 
     From DE 10 2016 011 324 A1, a method for controlling a towing vehicle when it is approaching and coupling to a trailer vehicle is known. The rear surrounding area behind the towing vehicle is captured, for example with a camera; an offset distance and an offset angle between the towing vehicle and the trailer vehicle are evaluated from the data collected; at least one driving trajectory is calculated, by means of which the towing vehicle can be driven autonomously to a coupling location, and the towing vehicle is driven autonomously and coupled in accordance with the driving trajectory. 
     SUMMARY 
     A transverse steering method for moving a vehicle including active steering to a target position includes: performing distance and/or angle measurements between the vehicle and the target position enabling the derivation of location and orientation data; deriving the location and orientation data; filtering the location and orientation data into current values, which include current location values and current orientation values; performing control which derives a target steering angle from the current values; and realization of the target steering angle by acting on the active steering of the vehicle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be described in even greater detail below based on the exemplary figures. The invention is not limited to the exemplary embodiments. All features described and/or illustrated herein can be used alone or combined in different combinations in embodiments of the invention. The features and advantages of various embodiments of the present invention will become apparent by reading the following detailed description with reference to the attached drawings which illustrate the following: 
         FIG. 1  shows schematically in a side view a use case where the target position is a coupling position; 
         FIG. 2  shows schematically in a plan view the geometric relationships, exemplary definitions and quantities used here using the example of a semi-trailer truck in front of a semi-trailer; 
         FIG. 3  shows a block diagram for the explanation of a first transverse steering method according to an embodiment of the invention; 
         FIG. 4  shows a block diagram for the explanation of a second transverse steering method according to an embodiment of the invention; 
         FIG. 5  shows a block diagram for the explanation of a third transverse steering method according to an embodiment of the invention; and 
         FIG. 6  shows a block diagram for the explanation of a fourth transverse steering method according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     With the method of the prior art it can be considered disadvantageous that a driving trajectory calculated at the beginning of the movement process can be significantly in error, because typically the starting position is only known inaccurately then. In particular, errors of a measured starting orientation lead to a large lateral offset, especially for a large distance to be travelled. 
     It can also be considered disadvantageous that measured values of the position measurement are typically noisy, in other words contain error components. 
     An embodiment of the invention provides transverse steering methods and transverse steering devices for moving a vehicle to a target position, with which these disadvantages are avoided. Vehicles which are set up to carry out these transverse steering methods will also be provided. 
     Transverse steering methods for moving a vehicle into a target position include, according to an embodiment of the invention:
         that distance and/or angle measurements are carried out between the vehicle and the target position, which allow the derivation of location and orientation data,   that the derived location and orientation data are filtered into current values, which include current location values and current orientation values,   that control is carried out which derives the target steering angle from the current values,   and that the target steering angles are realized by acting on an active steering of the vehicle.       

     In an advantageous development, the transverse steering methods according to an embodiment of the invention include that the control is in the form of a cascade control, with which a target orientation is derived from the current location values in an outer control circuit, and the target steering angle is derived from the target orientation and the current orientation value in an inner control circuit. 
     In a further advantageous development, the transverse steering methods according to an embodiment of the invention include that filtering the location and orientation data is in the form of Kalman filtering, in which the location and orientation data are processed to the current values taking into account the vehicle&#39;s measured driving characteristics, quality values and a motion model of the vehicle. 
     Transverse steering devices for moving a vehicle with active steering into a target position include according to an embodiment of the invention:
         sensors and markings which are provided and distributed to the vehicle and the target position in such a way that distance and/or angle measurements between the vehicle and the target position can be used to derive location and orientation data,   a measuring device set up to carry out distance and/or angle measurements between the vehicle and the target position by means of the sensors and markings, and from which the location and orientation data of the vehicle are derived,   a measured value filter, which is set up to derive current values which include current location values and current orientation values from the location and orientation data,   a controller which is set up in such a way that target steering angles are derived from the current values and are realized by acting on the active steering.       

     In an advantageous development, the transverse steering devices according to an embodiment of the invention include that the controller is in the form of a cascade controller, with a lateral offset controller which is set up in such a way that it derives a target orientation from the current location values, and an orientation controller which is set up in such a way that it derives the target steering angle from the target orientation and the current orientation value. 
     In a further advantageous development, the transverse steering devices according to an embodiment of the invention include that the measured value filter is in the form of a Kalman filter, which is set up in such a way that the location and orientation data are processed into the current values taking into account the driving characteristics measured on the vehicle, quality values and a motion model of the vehicle. 
     A vehicle according to an embodiment of the invention, in particular a driven towing vehicle, is set up to perform a transverse steering method according to an embodiment of the invention and/or has a transverse steering device according to an embodiment of the invention. 
     Position, as in the case of target position, is understood here as comprising a location and an orientation specification. For example, the location can be specified by coordinates in an absolute or relative two-dimensional or three-dimensional coordinate system. The orientation can be provided by a two-dimensional or three-dimensional angle specification together with an agreement regarding the reference point and the reference angle. 
     Transverse steering here refers to an effect on the angles of the wheels of the steering axle of the vehicle. In the case of vehicles with multiple steering axles, this may also include an appropriate action on axles other than the main steering axle. 
     The target position can be a coupling position, i.e. a position in the sense of location and orientation at which the vehicle can be coupled to a trailer or semi-trailer vehicle. 
     The target position can also be a loading position, i.e. a position at a loading ramp that makes it possible to load or unload the vehicle. The x-axis of the coordinate system, which is fixed with respect to the target position, is preferably placed here in the direction in which the loading position must be approached, for example perpendicular to an edge of a loading ramp. 
     The target position can also be a charging position, i.e. a position at which the vehicle can be supplied by connection to a supply device equipment such as for fuel, battery charge or hydraulic fluid. The x-axis of the coordinate system, which is fixed with respect to the target position, is preferably placed here in the direction in which the charging position must be approached, for example at a suitable distance longitudinally next to the supply device. 
     The target position can also be a parking position in a vehicle parking space prepared for partial automation. The x-axis of the coordinate system, which is fixed with respect to the target position, is preferably placed here in the direction in which the parking position must be entered. 
     The sensor of the vehicle can be, for example, a laser scanner or a LIDAR, a still camera, or a video camera. 
       FIG. 1  shows schematically a use case in a side view, where the target position is a coupling position. The vehicle here is a semi-trailer  101  and comprises active steering  107 , two sensors  103  horizontally distanced from the longitudinal axis and a fifth wheel  102 . The semi-trailer  101  is at a distance in front of a semi-trailer  106 , which comprises a fifth-wheel kingpin  104  and foldable supports  109 . Reaching the target position is given here when the fifth wheel  102  has been positioned centrally below the fifth-wheel kingpin  104  in plan view. The supports  109  comprise reflectors  105 , which are designed and mounted in such a way that they can be sensed by measurement  108  by the sensors  103  in terms of their direction and/or distance. 
       FIG. 2  shows schematically in plan view the geometric relationships, definitions and variables used here using the example of a semi-trailer truck  207  as a vehicle in front of a partially indicated stationary semi-trailer  208  with a fifth-wheel kingpin  205 . The origin of a stationary right-angled coordinate system with x-direction  201  and y-direction  211  lies in the fifth-wheel kingpin  205 , which is assumed to be the target location. The x-direction corresponds to the longitudinal axis of the semi-trailer  208 . The semi-trailer truck  207  comprises an unsteered rear axle  206  and a steered front axle  210  and has a reference point  209 , a position, an orientation, a steering angle beta  204  and a longitudinal axis  212 . The reference point  209  for the description of the semi-trailer truck  207  is the center of its fifth wheel. The position of the semi-trailer truck  207  is defined by the x-coordinate and the y-coordinate of this reference point  209 . Specifically, the y-coordinate of the reference point  209  is also referred to as the lateral offset  202 . The orientation of the semi-trailer truck  207  is defined as the angle alpha  203 , which the longitudinal axis  212  of the semi-trailer truck  207  includes with the x-direction  201 . The steering angle beta  204  of the semi-trailer truck  207  is defined as the angle which the wheels of the front axle  210  include with a parallel to the longitudinal axis  212  of the semi-trailer truck  207 . 
       FIG. 3  shows a block diagram for explaining of a first transverse steering method  300  and a first transverse steering device  317  according to an embodiment of the invention. The transverse steering method  300  involves a target offset specification  301 , a controller  303  acting on a vehicle  304 , a measuring device  306 , and a measured value filter  305 . The controller  303  obtains a target lateral offset or a target offset  308  from the target offset specification  301 , as well as values for a current lateral offset  311  and a current orientation  312  of the vehicle  304  from the measured value filter  305 . From these input data, the controller  303  derives a target steering angle  310 , which is then realized in the vehicle  304  by an action on the active steering  107 . The target offset  308 , i.e. the lateral offset  202  to be aimed for at the end of the movement, is zero in most practical cases, whereas deviating values may be appropriate in special cases. The measuring device  306  carries out distance and/or angle measurements between the vehicle  304  and a target position  307 , which are designed in such a way that location and orientation data  313  of the vehicle  304  can be derived therefrom, and it derives them. The measured value filter  305  processes the location and orientation data  313  and derives therefrom the values for the current lateral offset  311  and the current orientation  312  of the vehicle  304 . 
     For the measurements  315  to be carried out by the measuring device  306  between the vehicle  304  and the target position  307 , sensors and detectable markings interact which may be arranged in different ways. For example, as shown in  FIG. 1 , the sensors  103  can be fixed on the vehicle  101 ,  304  and the markings  105  can be fixed at a known distance from the target position  104 . It is advantageous here that the sensor signals are already available in the vehicle  101 ,  304  and do not have to be transmitted there first. 
     The reverse arrangement, i.e. sensors fixed at a known distance from the target position and markings fixed to the vehicle  304 , can be used alternatively. The advantage would be that the measurements of the sensors would be created directly in a coordinate system relative to the target position and therefore would not have to be converted. 
     The number of sensors and markings as well as the type of measurements to be carried out, for example angle or distance measurements, are based on the known principles of triangulation. A possible configuration includes two sensors spaced apart on the vehicle and two markings spaced apart and fixed at a known distance from the target position. For each individual marking, a distance or angle measurement by each of the sensors is sufficient to determine the location of the marking relative to the location of the sensors. The relative orientation between the vehicle and the target position can then be derived from the locations of the two markings. 
     The location and orientation values determined relative to a first coordinate system can be converted to any other displaced and/or rotated coordinate system using known equations. 
     In order to reduce measurement inaccuracies or to increase system availability, it may also be appropriate to use further additional sensors and/or additional markings. 
       FIG. 4  shows a block diagram for the explanation of a second transverse steering method  400  and a second transverse steering device  417  according to an embodiment of the invention. The transverse steering method  400  involves a target offset specification  401 , a lateral offset controller  402 , an orientation controller  403  acting on a vehicle  404 , a measuring device  406 , and a measured value filter  405 . The lateral offset controller  402  and the orientation controller  403  together form a cascade controller  416 . 
     The lateral offset controller  402  receives as an input variable the target lateral offset or the target offset  408  supplied by the target offset specification  401  minus the current lateral offset  411  supplied by the measured value filter  405 , from which the lateral offset controller  402  derives a target orientation  409 . The orientation controller  403  receives as an input variable the target orientation  409  minus the current orientation  412  supplied by the measured value filter  405 , from which the orientation controller  403  derives a target steering angle  410 , which is then realized in the vehicle  404  by action on the active steering  107 . 
     What has been stated above regarding the first transverse steering method  300  also applies accordingly for the target offset  408 , the measuring device  406 , the location and orientation data  413  and the measured value filter  405 , as well as for the sensors and markings. 
       FIG. 5  shows a block diagram for the explanation of a third transverse steering method  500  and a third transverse steering device  517  according to an embodiment of the invention. The transverse steering method  500  involves a target offset specification  501 , a controller  503  acting on a vehicle  504 , a measuring device  506 , and a measured value filter  505 . What has been stated above regarding the first transverse steering method  300  also applies accordingly for the target offset specification  501 , the controller  503 , the target steering angle  510  and the measuring device  506 . The measured value filter  505  is a Kalman filter, which not only receives the location and orientation data  513  from the measuring device  506 , but also a measured speed and a measured steering angle as driving characteristics  514  from the vehicle  504  and derives the current lateral offset  511  and the current orientation  512  therefrom and from a motion model  518  of the vehicle  504 . 
       FIG. 6  shows a block diagram for the explanation of a fourth transverse steering method  600  and a fourth transverse steering device  617  according to an embodiment of the invention. The transverse steering method  600  involves a target offset specification  601 , a lateral offset controller  602 , an orientation controller  603  acting on a vehicle  604 , a measuring device  606 , and a measured value filter  605 . What has been stated above regarding the second transverse steering method  400  also applies accordingly for the lateral offset controller  602  and the orientation controller  603  and what has been stated above regarding the third transverse steering method  500  applies for the measured value filter  605  in the form of a Kalman filter. The lateral offset controller  602  and the orientation controller  603  together form a cascade controller  616 . 
     An additional influencing factor for all transverse steering methods  300 ,  400 ,  500 ,  600  is the longitudinal control, i.e. the action on the drive train and braking system of the vehicle. This causes the variation of the vehicle speed over time and can be specified completely independently, for example automatically, partially automatically, manually by remote control by a driver outside the vehicle or manually by a driver in the vehicle. The effect of the longitudinal control is reflected on the one hand in the changing location measured values over time, but also on the other hand in the driving characteristics  514 ,  614  which include a measured speed, and in this way is included in the transverse steering method. 
     The sensors  103  of the vehicle  101 ,  207 ,  304 ,  404 ,  504 ,  604  used for measurement  306 ,  406 ,  506 ,  606  can be a laser scanner, a LIDAR or a still camera, or a video camera, for example. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. It will be understood that changes and modifications may be made by those of ordinary skill within the scope of the following claims. In particular, the present invention covers further embodiments with any combination of features from different embodiments described above and below. Additionally, statements made herein characterizing the invention refer to an embodiment of the invention and not necessarily all embodiments. 
     The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article “a” or “the” in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of “or” should be interpreted as being inclusive, such that the recitation of “A or B” is not exclusive of “A and B,” unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of “at least one of A, B and C” should be interpreted as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of each of the listed elements A, B and C, regardless of whether A, B and C are related as categories or otherwise. Moreover, the recitation of “A, B and/or C” or “at least one of A, B or C” should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B and C. 
     REFERENCE CHARACTERS 
     
         
           101  Semi-trailer truck 
           102  Fifth wheel 
           103  Sensors 
           104  Fifth wheel king pin 
           105  Reflectors 
           106  Semi-trailer 
           107  Active steering 
           108  Measurement 
           109  Supports 
           201  x-direction 
           202  Lateral offset 
           203  Orientation angle alpha 
           204  Steering angle beta 
           205  Fifth wheel king pin=coordinate origin 
           206  Rear axle 
           207  Semi-trailer truck 
           208  Semi-trailer 
           209  Reference point 
           210  Front axle 
           211  y-direction 
           212  Longitudinal axis of the semi-trailer 
           300  Transverse steering method 
           301  Target offset specification 
           303  Controller 
           304  Vehicle 
           305  Measured value filter 
           306  Measurement device 
           307  Target position 
           308  Target offset 
           310  Target steering angle 
           311  Current lateral offset 
           312  Current orientation 
           313  Location and orientation data 
           315  Measurement 
           317  Transverse steering device 
           400  Transverse steering method 
           401  Target offset specification 
           402  Lateral offset controller 
           403  Orientation controller 
           404  Vehicle 
           405  Measured value filter 
           406  Measurement device 
           407  Target position 
           408  Target offset 
           409  Target orientation 
           410  Target steering angle 
           411  Current lateral offset 
           412  Current orientation 
           413  Location and orientation data 
           415  Measurement 
           416  Cascade controller 
           417  Transverse steering device 
           500  Transverse steering method 
           501  Target offset specification 
           503  Controller 
           504  Vehicle 
           505  Kalman filter as measured value filter 
           506  Measurement device 
           507  Target position 
           508  Target offset 
           510  Target steering angle 
           511  Current lateral offset 
           512  Current orientation 
           513  Location and orientation data 
           514  Driving characteristics 
           515  Measurement 
           517  Transverse steering device 
           518  Motion model 
           519  Quality value 
           600  Transverse steering method 
           601  Target offset specification 
           602  Lateral offset controller 
           603  Orientation controller 
           604  Vehicle 
           605  Kalman filter as measured value filter 
           606  Measurement device 
           607  Target position 
           608  Target offset 
           609  Target orientation 
           610  Target steering angle 
           611  Current lateral offset 
           612  Current orientation 
           613  Location and orientation data 
           614  Driving characteristics 
           615  Measurement 
           616  Cascade controller 
           617  Transverse steering device 
           618  Motion model 
           619  Quality value