Patent Publication Number: US-10782656-B2

Title: Method and device for influencing a vehicle behavior

Description:
FIELD OF THE INVENTION 
     The present invention relates to a method and device for influencing a vehicle behavior. 
     BACKGROUND INFORMATION 
     The behavior of vehicles, in particular motor vehicles, is determined by control units, for example engine control units. These control units are connected via a data bus, for example a CAN bus, among one another and to sensors and actuators for influencing the vehicle behavior. 
     A functional software runs on the control units, which reads pieces of information about the vehicle state from the data bus, evaluates these, and activates actuators for influencing the vehicle behavior as a function of the result of the evaluation. 
     The functional software is typically adapted to a certain vehicle with the aid of parameterization. For this purpose, measurements of the vehicle state in certain driving situations are usually conducted. These measurements are analyzed. If necessary, parameters are changed as a function of the result of the analysis. 
     A quality criterion is used to assess the actual vehicle behavior. The parameterization is completed when the quality criterion is met. 
     The vehicle must be physically available in order to conduct the measurements and for the parameterization. For example, the measurements are conducted on a test bench or on a test track. 
     This gives rise to the problem that, due to the availability of vehicles, the parameterization is only possible with the aid of individual vehicles or individual variants, for example a single engine, and using a very limited scope of measuring data. 
     SUMMARY OF THE INVENTION 
     It is thus an object of the present invention to improve a method and a device of the type mentioned at the outset so that the parameterization is simplified, and the result of the parameterization is further improved. 
     This object may be achieved according to the present invention by a method and a device as recited in the independent claims. 
     Technical measures thus make it possible to parameterize a functional software of a vehicle by:
         receiving a data set including information about a vehicle state in particular via a local data bus at a local processing unit in the vehicle;   transmitting the information about the vehicle state via a communication interface addressed to a remote processing unit outside the vehicle; and   receiving, at the local processing unit in the vehicle, information about at least one parameter for influencing the vehicle behavior, which was transmitted from the remote processing unit outside the vehicle, via the communication interface.       

     An information content of a received data set may be ascertained, it being ascertained as a function of the information content of the received data set and a predetermined model for a vehicle behavior as to whether an information gain exists as a result of the received data set. 
     The information content of a data set may be compared to a received information content, a data set being transmitted via the communication interface as a function of the result of the comparison. 
     A data set which is to be transmitted via the communication interface may be stored in a buffer prior to transmission, the content of the buffer being transmitted via the communication interface when the information content exceeds a predefined threshold value for the information content. 
     Data sets may be sorted as a function of their respective information content. 
     A data set may be deleted when a memory space usage exceeds a threshold value for the memory space usage, and the information content assigned to the data set falls below a predefined threshold value for the information content. 
     A parameter optimization may be carried out at the remote processing unit outside the vehicle as a function of one or multiple data set(s) received by the local processing unit in the vehicle. 
     The information content may be ascertained at the remote processing unit outside the vehicle as a function of multiple data sets received by the local processing unit in the vehicle. 
     The parameter optimization or ascertainment of the information content may be carried out as a function of multiple data sets which are received by different vehicles from the remote processing unit outside the vehicle. 
     A device and a computer program are also provided. 
     Further advantageous embodiments are the subject matter of the further descriptions herein. 
     Exemplary specific embodiments of the present invention are described hereafter with reference to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically shows one embodiment of a system for parameterization. 
         FIG. 2  schematically shows a portion of a method for parameterization. 
         FIG. 3  schematically shows portions of a measurement. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  schematically shows a system for parameterization. A local processing unit  100  in a vehicle is connected via a communication interface  300  to a remote processing unit  400  outside a vehicle. Via communication interface  300 , a link via a radio network, for example a mobile communication network, is possible. Communication interface  300  is based on LTE, LTE Advanced or UMTS, for example. 
     Local processing unit  100  includes a transmitter  110  for transmitting data via communication interface  300 . Transmitter  110  may include an output memory for data sets. Data sets are also referred to hereafter as measuring segments. 
     Local processing unit  100  includes a receiver  120 . Receiver  120  may include an input memory for data sets. 
     Local processing unit  100  is connectable via a communication interface  400  to a control unit  500  of a vehicle. Data interface  400  is a CAN bus interface, for example. A radio interface or another wired interface may also be provided. 
       FIG. 3  schematically shows a portion of a measurement used for the parameterization of a functional software. This measurement is received in local processing unit  100  by receiver  120 . The measurement may be recorded by control unit  500 . 
     For example, curves of a first characteristic U, for example an engine speed, and of a second characteristic Y, for example an engine torque, are recorded as chronological curves.  FIG. 3  shows a chronological curve of two measured variables ui and y in this regard. The measurement is divided into measuring segments dT. These are illustrated in  FIG. 3  by lines which are represented at distance dT perpendicular to the time axis. 
     A measurement U(T), Y(T) includes a time value t, or multiple time values t, and values of measured variables ui and y corresponding thereto. A measuring segment U(dTk), Y(dTk) includes a corresponding subset of values. 
     Local processing unit  100  furthermore includes a further receiver  130 . Receiver  130  is configured to receive data, in particular information about parameters θ, or an information content I(T) via communication interface  300  from remote processing unit  400 . 
     Local processing unit  100  moreover includes a first evaluation unit  140 , a second evaluation unit  150 , and a decider  160 . 
     First evaluation unit  140  is configured to establish a further information content I(dT), which is supplied by the measuring segment with respect to parameter θ, as a function of a measuring segment incoming at receiver  120  and as a function of information about a parameter θ received by further receiver  130 . 
     Second evaluation unit  150  is configured to ascertain, as a function of the result of the evaluation by first evaluation unit  140  and as a function of information about parameter θ received by further receiver  130 , as to whether an information gain with respect to parameter θ was achieved as a result of the incoming measuring segment. 
     Decider  160  is configured to generate a signal for activating transmitter  110 , as a function of the result of the evaluation by second evaluation unit  150  and the information about information content I(T) received by further receiver  130 . 
     Decider  160  compares information content I(dT) of the measuring segment to a predefined threshold value for the information content. When information content I(dT) of the measuring segment exceeds the predefined threshold value for the information content, decider  160  signals to transmitter  110  that an information gain exists. 
     When transmitter  110  receives this signal, transmitter  110  transmits the content of the output memory via communication interface  300  to remote processing unit  400 . 
     The threshold value may be determined as a function of information content I(T) received by further receiver  130 . The threshold value for the information content is, for example, information content I(T) received by further receiver  130 . 
     A method for parameterizing the functional software running in the control unit of a vehicle is described hereafter based on  FIG. 2 . 
     The method begins, for example, by starting a parameterization function of a software running on local processing unit  100  in the vehicle. 
     After the start, information about the vehicle state of the vehicle is received in a step  201 . The information may be received at local processing unit  100  in the vehicle on which the parameterization function is running. The information about the vehicle state may be transmitted via a local data bus to local processing unit  100  in the vehicle. 
     A data set which may be transmitted as information about the vehicle state includes mutually assigned data of a measuring segment. For example, curves of first characteristic U, for example the engine speed, and of second characteristic Y, for example the engine torque, are recorded as chronological curves. In this case, a data set includes, for example, multiple triples (ui, y, t), each made up of a value of the engine speed, a value of the engine torque, and the time at which both were measured. 
     The information may be recorded by a vehicle sensor or by control unit  500  in the vehicle. 
     The entire measuring segment may be transmitted in one data set. It may also be provided to transmit measuring data continuously to local processing unit  100 . In this case, it may be provided to divide received measuring data in local processing unit  100  into predetermined time periods dT as measuring segments. 
     Thereafter, a step  202  is carried out. 
     In step  202 , a model M(θ) is ascertained as a function of the received data set and the information about parameter θ which was received by further receiver  130 . Model M(θ) forms an estimated chronological curve of characteristics U or Y. 
     Thereafter, a step  203  is carried out. 
     In step  203 , information content I(dTK) of the received data set is ascertained and assigned thereto. Information content I(dTK) is a measure with the aid of which the relevance of the received data set with respect to the parameterization may be assessed. For example, Fisher information is used for this purpose. The Fisher information supplies a measure for the quality of a parameter estimation with respect to model M(θ). 
     The determination of the information content takes place for a measuring segment dTK, for example. This exists for a certain time duration dTK={tk−N, . . . tk}. 
     For this purpose, information content I(dTk) of a measuring segment U(dTk), Y(dTk) is assessed. 
     The goal of the parameterization is to achieve, with the aid of model M(θ), i.e., the estimated chronological curve of characteristics U or Y, the actual chronological curve from the measurement of characteristics U or Y with a predefined or predefinable quality. For a parameter θ which influences the curve of characteristics U or Y in the vehicle, a piece of information I(θ) from the measurement with respect to parameter θ of model M(θ) is crucial:
 
 I (θ)= I ( Y ( dTk ), M ( U ( dTk ),θ))
 
     Information content I(dTK)=I(θ) depends both on the measurement in measuring segment U(dTk), Y(dTk) and on model M(θ) itself. For example, Fisher information IF is used for assessing the information. In this case, information content I(dTK)=IF(θ). 
     The Fisher information is used as follows in the example: 
     
       
         
           
             
               
                 I 
                 F 
               
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                 ( 
                 θ 
                 ) 
               
             
             = 
             
               E 
               [ 
               
                 
                   
                     ( 
                     
                       
                         ∂ 
                         
                           ∂ 
                           θ 
                         
                       
                       ⁢ 
                       
                         log 
                         ⁡ 
                         
                           ( 
                           
                             L 
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                               ( 
                               
                                 Y 
                                 ; 
                                 θ 
                               
                               ) 
                             
                           
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                   2 
                 
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     using the probability density function L(Y; θ) of Y on the condition θ, or the probability function for θ. Function L(Y; θ) represents a stochastic description of model M(θ). 
     Thereafter, a step  204  is carried out. 
     In step  204 , data sets in the buffer are sorted as a function of their respective information content. Information content I(dTK) of multiple data sets relative to one another may be compared for this purpose. 
     Thereafter, a step  205  is carried out. 
     In step  205 , it is checked whether the information content of the received data set exceeds a predefined threshold value for the information content. With this, it is established whether an information gain with respect to the parameter was achieved as a result of the received data set. 
     It is advantageous for the parameterization concept when information content I(dTK) of a measuring segment U(dTK), Y(dTK) assessed not only in absolute terms, i.e., using a scalar metric, but when information content I(dTK) of multiple measurements relative to one another is assessed. A measure of the similarity of information is provided hereafter. 
     When using Fisher information IF, a measure is the comparison of the main components of two pieces of Fisher information IF 1 ; IF 2 . 
     In the example, a first piece of Fisher information IF 1  is determined as information content I(dK) of measuring segment U(dTK), Y(dTK) for the first main component. 
     In the example, the second main component for piece of Fisher information IF 2  is received as information content I(T) from local processing unit  100  at further receiver  130 . 
     In the example, remote processing unit  400  determines this information content I(T) with the aid of Fisher information, as is described for the determination of information content I(dK) of a measuring segment. From this results Fisher information IF(T) of remote processing unit  400 . This determination takes place, for example, with the aid of one measuring segment U(dTK), Y(dTk) or with the aid of multiple measuring segments Ui(dTk), Yi(dTk). Measuring segment U(dTk), Y(dTk) or measuring segments Ui(dTk), Yi(dTk) may stem from one or multiple vehicle(s). 
     Another measure is the use of the Cramer-Rao inequality, which indicates a lower bound
 
Cov(θ)≥ I   F   −1 (θ*)
 
for the covariance Cov(θ) of the error of the parameter estimation for an unbiased parameter estimator, having knowledge of the true θ*. Since θ* is not known, the instantaneously estimated θ′ must be used. If a measurement now significantly reduces the covariance, estimated by IF −1 (θ′), it supplies a high information gain. In this case, remote processing unit  400  determines instantaneously estimated θ′, for example. In this case, a transmission of instantaneously estimated θ′ instead of the transmission of information content I(T) to further receiver  130  may take place. Local processing unit  100  ascertains covariance Cov(θ′) or the estimation with the aid of IF −1 (θ′).
 
     This means that, the threshold value for the information content may be information content I(T) which was received by further receiver  130 . 
     As an alternative, the threshold value is a threshold for the reduction of covariance Cov(θ′). 
     If the predefined threshold value for the information content is exceeded, a step  206  is carried out; otherwise a step  207  is carried out. 
     In step  206 , a content of the buffer is transmitted via communication interface  300 . The information about the vehicle state may be transmitted via communication interface  300  addressed to a remote processing unit  400  outside the vehicle. All data sets stored in the buffer may be transmitted. 
     This means that a data set is transmitted via communication interface  300  as a function of the result of the comparison in step  205 . 
     Thereafter, step  207  is carried out. 
     In step  207 , a data set is deleted from the buffer when the information content assigned to the data set falls below a predefined threshold value for the information content. All data sets which in the sorting of the data sets may be situated below the threshold value for the information content are deleted. 
     Thereafter, a step  208  is carried out. 
     Multiple incoming data sets including information about the vehicle state may be stored for a predetermined time duration, for example 10 minutes, one hour, or one day, in the local memory prior to transmission. 
     For this purpose, steps  201  and  207  are repeated, for example for the predetermined time duration. Only thereafter is step  208  carried out. 
     In step  208 , information about at least one parameter θ for influencing the vehicle behavior, which was transmitted by remote processing unit  400  outside the vehicle, is received at local processing unit  100  in the vehicle via the communication interface. 
     It may be provided, in step  208 , to wait for the reception of parameters θ at communication interface  300  and to repeat steps  201  through  207  during the waiting period. 
     Thereafter, a step  209  is carried out. 
     In step  209 , a received parameter θ is stored in local processing unit  100 . 
     Parameters θ which are received at local processing unit  100  in the vehicle may be used to influence the vehicle behavior with the aid of the functional software. 
     Parameters θ may be transmitted from local processing unit  100  in the vehicle to a control unit. The transmission may be started automatically or by a corresponding function of the parameterization software. 
     Thereafter, step  201  is carried out. If steps  201  through  207  were repeated, steps  208  and  209  are carried out in parallel, for example, and the parallel process is ended after step  209 . 
     To protect against erroneous parameters or to avoid the parameterization with parameters from non-authorized senders, encryption techniques or authentication techniques, such as a virtual private network, known as VPN, connection, via an Internet connection, for example a TCP/IP connection, or with the aid of an LTE Advanced connection may be used. In this case, communication interface  300  is configured to use the corresponding protocols. 
     Steps of a method which runs on remote processing unit  400  are described hereafter. This method starts, for example, when data sets from local processing unit  100  arrive at remote processing unit  400 . Information content I(T) may be determined by remote processing unit  400  as described above as Fisher information IF(T). If the Cramér-Rao inequality is used, it may also be provided to ascertain and to transmit parameter θ′. 
     After the start, a parameter optimization is carried out at remote processing unit  400  outside the vehicle as a function of one or multiple data set(s) received from local processing unit  100  in the vehicle. 
     Information content I(T) may be ascertained on remote processing unit  400  outside the vehicle as a function of multiple data sets received from local processing unit  100  in the vehicle. 
     The parameter optimization or the ascertainment of the information content may be carried out as a function of multiple data sets which are received by different vehicles from remote processing unit  400  outside the vehicle. For this purpose, it may be provided to use data sets of different vehicles together at remote processing unit  400 . For this purpose, remote processing unit  400  is at least intermittently in communication with local processing units  100  of different vehicles. 
     Remote processing unit  400  includes a memory  450 , for example a database, in which a recorded data set of a vehicle or the recorded data sets are stored assigned to the corresponding vehicles. 
     Remote processing unit  400  includes a processor  460 , in particular an optimizer or a parameter optimizer. A parameter is ascertained by processor  460  from a data set stored in memory  450 . Parameter θ may be assigned by processor  460  to the vehicle to which the recorded data sets from the memory are assigned. 
     Parameter θ is transmitted via a data line from processor  460  to further receiver  130  via communication interface  300 . Parameter θ may be transmitted to further receiver  130  of the vehicle to which parameter θ is assigned. 
     Parameter θ is transmitted via a further data line to a further processor  470  within remote processing unit  400 . 
     Further processor  470  is configured to ascertain information content I(T) as a function of parameter θ and a data set U(dTK), Y(dTK), which is assigned to the vehicle to which parameter θ is assigned. For this purpose, further processor  470  is configured to read a corresponding data set U(dTK), Y(dTK) from memory  450 . 
     Further processor  470  is configured to transmit information content I(T) via a data line from processor  470  to further receiver  130  using communication interface  300 . 
     Information content I(T) may be transmitted to further receiver  130  of the vehicle to which information content I(T) is assigned. 
     It may be provided to evaluate multiple data sets Ui(dTK), Yi(dTK) of the same vehicle and/or multiple data sets Ui(dTK), Yi(dTK) of different vehicles in order to ascertain a parameter θ and an information content I(T). 
     It may be provided to ascertain one or multiple parameter(s) θ and/or multiple values for information content I(T). 
     It may be provided to transmit parameters θ and/or values of information content I(T) to the respectively assigned vehicle and/or multiple non-assigned vehicles.