Method for filtering a first measured quantity, computer equipment for executing the method, and vehicle with computer equipment

Abstract

A method for filtering a first measured quantity to determine (S4) a control parameter is described. The method includes reading (S1) time-dependent values ​​of the first measured quantity. Furthermore, the method includes determining (S2) values ​​of the first measured quantity as a function of the read-in time-dependent values, whereby the determined values ​​of the first measured quantity are calculated as a function of a second measured quantity. The method also includes filtering (S3) the determined values ​​of the first measured quantity. Finally, a method for determining (S4) a control parameter as a function of such filtered first measured quantity is described. A computer system (6) configured to execute such methods and a vehicle (2) equipped with such a computer system (6) are also described.

Description

[0001] The present invention relates to a method for filtering a first measured variable for determining a control parameter. Furthermore, the present invention relates to a method for determining a control parameter as a function of a first measured variable thus filtered. Furthermore, the present invention relates to a computer device configured to carry out such a method, as well as to a vehicle having such a computer device.

[0002] It is known from the prior art to filter measured variables in order to determine control parameters depending on the filtered measured variables. For example, an electric motor of a bicycle is controlled using a control parameter, wherein the control parameter is determined depending on the torque at a pedal of the bicycle. A torque signal may be a threshold signal due to pedaling, and therefore it may be necessary to filter this signal in order to determine the control parameter depending on the filtered torque signal. Filtering is carried out on a time-based basis, for example, filtering occurs over a constant time horizon or with respect to a specific period of time. This means that filtering differs in a situation in which a cyclist is pedaling at a high cadence from a situation in which the cyclist is pedaling at a low cadence.At a high cadence, filtering occurs slowly, while at a low cadence, filtering occurs quickly. This makes filtering cadence-dependent, and the torque is filtered depending on the pedal cadence. With the signal filtered differently for the two situations, the control parameters are determined differently for the two different cadences. This leads to different behavior of the electric motor. This different behavior of the electric motor is not desired by the driver.

[0003] DE 10 2021 211 270 B3 describes a method for controlling an electric motor of an electric bicycle, a motor control unit and a bicycle.

[0004] The object is therefore to provide a method for filtering measured variables and determining control parameters, which allows filtering of the measured variable independently of time and thus enables determination of the control parameter. This object is achieved by means of a method for filtering a first measured variable for determining a control parameter, having the features of claim 1. The object is further achieved by means of a computer device having the features of claim 11, and by means of a vehicle having the features of claim 12.

[0005] In a first aspect, the present invention relates to a method for filtering a first measured variable for determining a control parameter. The method can be a computer-implemented method. A computer device can be configured to carry out at least some or all steps of the method. The first measured variable can be a signal, for example, an electrical signal. When filtering the first measured variable, at least one of an amplitude and a phase position of the first measured variable embodied as a signal can be changed. By filtering, for example, unwanted components of the signal can be attenuated and alternatively or additionally suppressed. The control parameter can be determined as a function of the filtered first measured variable. The control parameter can, for example, be another signal, such as an electrical signal. The control parameter can, for example, be used to control an actuator, such as an electric motor.The actuator can therefore be controlled, for example, depending on the filtered first measured variable.

[0006] The method comprises reading in time-dependent values ​​of the first measured variable. The first measured variable can, for example, be a signal as a function of time. The method can further comprise measuring time-dependent values ​​of the first measured variable. During the reading process, measured time-dependent values ​​of the first measured variable can be read in.

[0007] Furthermore, values ​​of the first measured variable are determined depending on the time-dependent values ​​read in. The determined values ​​of the first measured variable are determined as a function of a further, second measured variable. The second measured variable and the first measured variable can be different. For example, the first measured variable can be a first physical measured variable, and the second measured variable can be a further, different physical measured variable. The determined values ​​of the first measured variable can be determined, for example, as a signal as a function of the second measured variable. The determination of values ​​can comprise a transformation of values ​​of the first measured variable from a time period into a space of the second measured variable. The determined values ​​of the first measured variable can be independent of time.

[0008] Furthermore, the determined values ​​of the first measured variable are filtered. During filtering, for example, the amplitude and, alternatively or additionally, the phase position of the determined values ​​of the first measured variable formed as a signal can be changed. This allows unwanted signal components, for example, in the space of the second measured variable, to be attenuated and, alternatively or additionally, suppressed. This filtering can be performed independently of time.

[0009] Thus, the method enables uniform filtering of the first measured variable for uniform determination of a control parameter depending on the filtered first measured variable. Filtering occurs in the space of the second measured variable and is thus independent of time. Accordingly, different values ​​of the first measured variable, for example, different signals as a function of time that behave differently as a function of time, are filtered uniformly, not in the time period, but in the space of the second measured variable. Accordingly, filtering occurs uniformly for different first measured variables. Thus, the control parameter is also determined uniformly for different values ​​of the first measured variable.For example, if a control parameter is determined for an actuator, this determination of the control parameter is carried out uniformly for the actuator, and the actuator is controlled uniformly, regardless of the time dependence of the first measured variable. Thus, the behavior of the controlled actuator is not influenced by the time dependence of the first measured variable.

[0010] In a further embodiment, the method can be characterized in that the method can be used to filter a first measured variable of a muscle-powered two-wheeler. The two-wheeler can be a bicycle with a drive device. The drive device can be an electric motor, for example. This electric motor can provide assistance for driving the bicycle in addition to the muscle power of a rider of the bicycle. The assistance by the drive device can only occur when the rider is pedaling. The first measured variable can be a torque at a pedal of the two-wheeler, and the second measured variable can be a crank angle. During reading, time-dependent torque values ​​can be read in. During determination, torque values ​​can be determined as a function of the crank angle depending on the read-in values.When filtering, the determined values ​​of torque as a function of the crank angle can be filtered.

[0011] This allows the torque to be filtered independently of time, and the filtered torque can be used to determine a control parameter. The control parameter can then be used to control the bicycle's drive system. This allows the torque to be measured over time. A threshold torque signal is read in as a result of the rider's pedaling. If the time-dependent torque values ​​were filtered over time, the torque would be filtered differently for a low cadence than for a high cadence. Filtering the torque as a function of the crank angle results in time-independent filtering and also filtering independent of the cadence, thus ensuring uniform filtering of the torque. This allows the control parameter to be determined uniformly depending on the filtered torque.The desired rider behavior can thus be detected and transmitted to the drive system. The drive system can therefore be controlled independently of the cadence. This allows the rider's input to be optimally detected and transmitted to the drive system as a control parameter. This eliminates the need to filter the torque as the first measured variable based on time. Instead, filtering can be performed based on the crank angle. The uniformly filtered torque can be used, for example, for other functions of the two-wheeler, such as automatic shifting of a transmission in the drive system. This allows, for example, the automatic shifting to be controlled uniformly.

[0012] According to a further embodiment, the method can be characterized in that values ​​of the first measured variable can be read in at different times during reading. Thus, values ​​of the first measured variable can be read in at equidistant different times during reading. For example, values ​​can be read in every 10, 20 or 50 ms. Values ​​of the first measured variable can be measured at different times, wherein the measurement of the first measured variable can be carried out periodically, for example. Furthermore, values ​​of the first measured variable can be determined for different values ​​of the second measured variable during determination. For example, values ​​for different values ​​of the crank angle can be determined for the torque as the first measured variable. For example, a torque can be determined for a first crank angle, and a torque can also be determined for a second, different crank angle.When filtering, specific values ​​of the first measured variable can be filtered for different values ​​of the second measured variable. For example, multiple torque values ​​can be filtered for different crank angle values.

[0013] This allows temporal ranges of the first measured variable, for example the torque, to be measured and read in. Depending on this, temporal ranges of the first measured variable, such as the torque, can be determined for ranges of the second measured variable, such as the crank angle. Furthermore, values ​​of the first measured variable can be filtered as a function of the second measured variable for ranges of the second measured variable. This allows not only individual values ​​of the first measured variable to be filtered, but ranges of the first measured variable can also be filtered. The method can therefore also be used to filter values ​​of the first measured variable across ranges and not just for individual values. The control parameter can therefore be determined, for example, using filtered values ​​of the first measured variable of a range.

[0014] According to a further embodiment, the method can be characterized in that the determination of values ​​of the first measured variable as a function of the second measured variable can occur for equidistant values ​​of the second measured variable. For example, the determination of torque values ​​as a function of the crank angle can occur for angularly equidistant values ​​of the crank angle. For example, time-dependent torque values ​​are read in for different points in time. For example, torque values ​​are determined for different values ​​of the crank angle. In this case, torque values ​​can be determined for angularly equidistant values. These torque values ​​are determined, for example, every 5 or 10 degrees of the crank angle.

[0015] This results in a transformation of time-dependent, for example, temporally periodic torque values ​​into equidistant values, such as angle-equidistant crank angle-dependent torque values. Since the crank angle can change non-linearly with time when pedaling, for example when pedaling is accelerated, such a transformation and determination of the values ​​of the first measured variable may be necessary in order to obtain equidistant values ​​for filtering. Thus, angularly equidistant torque values ​​can be provided for filtering, regardless of how these torque values ​​previously related to each other within the period. Filtering can thus be time-independent and, for example, evenly across values ​​of the second measured variable, such as the crank angle.

[0016] According to a further embodiment, the method can be characterized in that when determining values ​​of the first measured variable as a function of the second measured variable, a calculation can be carried out. The calculation can be an approximation. The calculation can be carried out using a formula. During the calculation, a value of the first measured variable can be calculated as a function of the second measured variable depending on at least two read-in values ​​of the first measured variable, for example two read-in values ​​at different times. During the calculation, a value of the first measured variable can be calculated as a function of the second measured variable depending on exactly two read-in values ​​of the first measured variable. For example, the calculation can be carried out using two time-dependent values ​​of the torque at two different times, wherein a value of the torque can be calculated as a function of the crank angle.

[0017] With such a method, the first measured variable can be calculated and approximated as a function of the second measured variable using values ​​of the first measured variable at different points in time. Such calculation and approximation can be performed particularly easily, for example, by depending only on two different values ​​read in at different times. This allows the method for filtering the first measured variable to be implemented easily.

[0018] According to a further embodiment, the method can be characterized in that the calculation can be carried out as a function of values ​​of the second measured variable. The calculation can be carried out as a function of two values ​​of the second measured variable, which can be read in. For example, the calculation can be carried out as a function of a difference between two equidistant values ​​of the second measured variable. For example, the calculation can be carried out as a function of a difference between two consecutive values ​​of the crank angle. Alternatively or additionally, the calculation can be carried out as a function of a difference between values ​​of the second measured variable, which relate to two temporally consecutive, time-dependent values ​​of the first measured variable that have been read in.

[0019] With such a method, the calculation can be performed more precisely, since the calculation can be performed as a function of the second measured variable, for example, in addition to the calculation as a function of at least two read values ​​of the first measured variable. Thus, the determination of values ​​of the first measured variable as a function of the second measured variable, and thus also the entire process for filtering the first measured variable to determine a control parameter, can be performed more precisely.

[0020] According to a further embodiment, the method can be characterized in that a moving average filter can be used when filtering the determined values. The moving average filter can be used with respect to multiple values ​​of the second measured variable. Thus, if the second measured variable is the crank angle, the moving average filter can be used with respect to half a revolution, one whole revolution, several half revolutions, or several whole revolutions of the pedal. Thus, an average value of the first measured variable, for example, the torque, can be determined during filtering.

[0021] This allows filtering of threshold signals, such as time-dependent torque values ​​read in. Such a moving average filter can be used to filter out high-frequency torque behavior. Thus, the torque filtering method can be used as the first measured variable to filter out high-frequency components in the torque signal as a function of crank angle. A control parameter can thus be determined independently of these high-frequency torque components. For example, if the rider pedals with varying force using their legs, filtering over several complete pedal revolutions can filter out varying force of pedaling. In extreme cases, the rider may also pedal with only one leg, and filtering with a moving average filter based on complete pedal revolutions could filter out a threshold in the torque value.In comparison, a time-based low-pass filter would have to be very slow. The disadvantage of very slow time-based low-pass filters is that they take a very long time to settle. This would also filter out any dynamics from the torque values.

[0022] According to a further embodiment, the method can be characterized in that the filtering of the determined values ​​can be performed cyclically. The filtering can be performed at specific times, for example, periodically. For example, the step of filtering the determined values ​​can be triggered cyclically.

[0023] Thus, the method can represent a temporally cyclical, constant recalculation by cyclically filtering the first measured variable as a function of the second measured variable. This allows the filtering of the first measured variable as a function of the second measured variable to occur cyclically with respect to time, for example, periodically. This allows a constant utilization of a computer device executing the method to be generated. This can occur independently of other measured variables, such as the second measured variable.

[0024] According to a further embodiment, the method can be characterized in that the filtering of the determined values ​​occurs when the second measured variable has a certain value. The certain value can be specified, for example, by a user, such as a developer, when implementing the method. For example, the filtering of the determined values ​​can occur when a certain crank angle has been exceeded or when a certain absolute crank angle has been reached. Thus, a crank angle-controlled filtering of the first measured variable can occur.

[0025] This allows filtering to occur more frequently at high cadence than at low cadence. Thus, the utilization of the computer device executing the process can be cadence-dependent. At low cadences, this can lead to lower utilization of the computer device than at high cadences.

[0026] A second aspect of the present invention relates to a method for determining a control parameter as a function of a filtered first measured variable. The method can be a computer-implemented method. A computer device can be configured to execute the method. The control parameter can be determined, for example, for a drive device. The drive device can be, for example, an electric motor of a bicycle. The filtered first measured variable can be filtered, for example, using a method according to an embodiment of the first aspect of the present invention.

[0027] A third aspect of the present invention relates to a computer device. The computer device can be, for example, a control unit of a vehicle, such as a bicycle. The computer device can be configured to execute a method according to an embodiment of the first and second aspects of the present invention.

[0028] A fourth aspect of the present invention relates to a vehicle having a computing device according to an embodiment of the third aspect of the present invention.

[0029] According to one embodiment, the vehicle can be characterized in that the vehicle is a human-powered two-wheeler with a drive device. The human-powered two-wheeler can be a bicycle. The drive device can be an electric motor. The computer device can be configured to filter a first measured variable and determine a control parameter based thereon. The first measured variable can be a torque at a pedal of the two-wheeler. The drive device can be controlled using the determined control parameter. Fig. 1 schematically shows steps of a method for filtering a first measured variable and for determining a control parameter. Fig. Figure 2 shows schematically a vehicle with a computer device for executing the Fig. 1 steps shown schematically. Fig. 3 shows an example of a first measured variable as a function of time and certain values ​​of the first measured variable as a function of a second measured variable.

[0030] Fig. 1 schematically shows steps of a method for filtering a first measured variable and for determining S4 a control parameter as a function of the filtered first measured variable.

[0031] Fig. 2 schematically shows a vehicle 2 with a computer device 6, wherein the computer device 6 is configured to carry out all steps of the schematically shown in Fig. 1. In one embodiment, the vehicle 2 is a muscle-powered two-wheeler with a drive device 4, wherein the computer device 6 and the drive device 4 are communicatively connected to one another. The computer device 6 is configured to filter a first measured variable and, depending thereon, to determine a control parameter in order to control the drive device 4 with the determined control parameter.

[0032] In the process for filtering a first measured variable, time-dependent values ​​of the first measured variable are read in (S1). The first measured variable is a torque M on a pedal of the two-wheeler. During the read-in process, values ​​of the first measured variable are read in at different times. Thus, values ​​of the torque M are read in at different times t-1, t, and t+1. Fig. 3 shows time-dependent values ​​of the torque M. Fig. Figure 3 shows that time-dependent values ​​of the torque M are read in for specific crank angles ϕ. The axes relating to time t and crank angle ϕ do not scale linearly to each other in the embodiment shown.

[0033] Furthermore, a determination S2 of values ​​of the first measured variable takes place as a function of the read-in time-dependent values, wherein the determined values ​​of the first measured variable are determined as a function of another, second measured variable. The second measured variable is the crank angle ϕ. Thus, the determination S2 of values ​​of the torque M takes place as a function of the crank angle ϕ. During the determination S2, values ​​of the first measured variable, here the torque M, are determined for different values ​​of the second measured variable, here the crank angle ϕ. These determined values ​​are in Fig. 3 with M1, M2, M3. The determination S2 of values ​​of the first measured variable, here the torque M, as a function of the second measured variable, here the crank angle ϕ, is carried out for equidistant values ​​of the second measured variable, i.e., for angularly equidistant values ​​of the crank angle ϕ. The determined values ​​of the torque M i are each spaced apart by a certain value of the crank angle, Δϕ2, Δϕ3.

[0034] When determining S2 values ​​of the torque M as a function of the crank angle ϕ, a calculation S2.1 is performed, whereby a value of the torque M is calculated as a function of the crank angle ϕ depending on at least two read values ​​of the torque M. The calculation S2.1 is performed using a formula: Mn=M(t)−M(t)−M(t−1)Δϕ(t)Δϕn or Mn=M(t−1)−M(t)−M(t−1)Δϕ(t)Δϕn with Δϕ(t) = ϕ(t) - ϕ(t-1).

[0035] A certain torque M nis calculated depending on two input torque values ​​at two times t, t-1. In one embodiment, the determined value M n representable as a function of time t, M n (t), where the time dependence refers to the read-in measured value M(t). Furthermore, the calculation S2.1 is carried out depending on values ​​of the crank angle ϕ. For this purpose, values ​​of the crank angle ϕ are read in at times t, t-1, ϕ(t) and ϕ(t-1). A specific torque M n as a function of the crank angle ϕ depending on a difference in the crank angle, Δϕ n , between two values ​​of the torque M n and a difference in the values ​​of the crank angle Δϕ (t) between two read-in time-dependent values ​​of the torque M(t). In this embodiment, Δϕ is shown as a function of time, Δϕ (t). In one embodiment, Δϕ n can be represented as a function of time t, Δϕ n(t). The representation as a function of time refers to the read-in measured value M(t). In another embodiment not shown here, instead of Δϕ n the sum over all Δϕ i with i = 1 to i = n is used in the formula for calculating the torque as a function of the crank angle ϕ. The first measured variable, here the torque M, is approximated as a function of the second measured variable, here the crank angle ϕ, using the calculation S2.1. In a further embodiment not explicitly shown here, the value M(t-1) is added in addition to the formula described above.

[0036] In Fig. 3 it can be seen that Δϕ1 and Δϕ4 are smaller than Δϕ2, Δϕ3. This is because values ​​of the torque M are determined for equidistant values ​​of the crank angle ϕ. If a first time-dependent value of the first measured variable, M(t-1), is available at a first time t-1, then this is also available for a specific crank angle ϕ. At a second, later time, another time-dependent value of the first measured variable is read in, here M(t) at a later crank angle ϕ. For example, the two values ​​are spaced apart in time by 10 ms and by 13° with respect to the crank angle ϕ. A torque Mo was already determined at an earlier time. A crank angle of 5° has not yet elapsed between the torque Mo and the read-in torque M(t-1), which represents the angularly equidistant distance of the embodiment described here.Thus, the remaining degrees are buffered and filled until the crank angle ϕ reaches 5° again since the last determined torque value, Mo. Therefore, Δϕ1 is less than 5°. Thus, the determination S2 of torque M values ​​as a function of the crank angle ϕ is implemented for equidistant values ​​of the crank angle ϕ, even if the read-in torque values ​​are not available at angularly equidistant values, whereby a buffer of the computer device 6, which is not explicitly mentioned in . Fig. 3 is used. The same applies to the end of the section between the two read values ​​M(t-1), M(t), i.e., the range Δϕ4. This angular range is also buffered and used to determine an additional torque not shown here.

[0037] Instead of an approximation using trapezoids, as shown schematically in Fig.As shown in Figure 3, in an embodiment not shown, the approximation is performed using rectangles, with the calculation S2.1 being performed using a different formula than the one described here. This also results in an approximation of the torque M as a function of the crank angle ϕ, although the approximation is different from the approximation described here.

[0038] Furthermore, a filtering S3 of the determined values ​​of the measured variable, in this case the torque M, takes place. During filtering S3, certain values ​​of the measured variable, in this case the torque M, are filtered for different values ​​of the second measured variable, in this case the crank angle ϕ. The determined values ​​M1, M2, M3 are filtered in this way. A moving average filter is used during filtering S3 of the determined values. This results in low-pass filtering of the determined values ​​of the torque as a function of the crank angle ϕ. The filtering S3 of the determined values ​​takes place cyclically, i.e. at specific times t. In an embodiment not shown, the filtering S3 of the determined values ​​takes place when the driver passes over a specific crank angle ϕ with the pedal while pedaling and the second measured variable therefore has a specific value.

[0039] Furthermore, the control parameter is determined S4 as a function of the filtered torque M as a function of the crank angle ϕ. The drive device 4 is controlled with the determined control parameter by sending the determined control parameter from the computer device 6 to the drive device 4. 2 vehicles 4 Drive device 6 Computer setup M torque t time ϕ crank angle S1 Reading in time-dependent values ​​of a first measured variable S2 Determining values ​​of the first measured quantity as a function of a second measured quantity S2.1 Calculating a value of the first measured quantity as a function of the second measured quantity S3 Filtering the determined values ​​of the first measured variable S4 Determining a control parameter

Claims

[1] Method for filtering a first measured variable for determining (S4) a control parameter, comprising the steps of: reading in (S1) time-dependent values of the first measured variable; determining (S2) values of the first measured variable as a function of the read-in time-dependent values, wherein the determined values of the first measured variable are determined as a function of a further, second measured variable; filtering (S3) the determined values of the first measured variable. [2] Method according to claim 1, characterized by that the method is used for filtering a first measured variable of a muscle-powered two-wheeler, and wherein the first measured variable is a torque (M) on a pedal of the two-wheeler and the second measured variable is a crank angle (ϕ). [3] Method according to one of the preceding claims, characterized bythat during reading (S1) values of the first measured variable are read in at different times, that during determining (S2) values of the first measured variable are determined for different values of the second measured variable, and that during filtering (S3) certain values of the first measured variable are filtered for different values of the second measured variable. [4] Method according to one of the preceding claims, characterized by that the determination (S2) of values of the first measured variable as a function of the second measured variable is carried out for equidistant values of the second measured variable. [5] Method according to one of the preceding claims, characterized by that when determining (S2) values of the first measured variable as a function of the second measured variable, a calculation (S2.1) takes place, wherein a value of the first measured variable is calculated as a function of the second measured variable depending on at least two read-in values of the first measured variable. [6] Method according to the preceding claim, characterized by that the calculation (S2.1) is carried out depending on values of the second measured quantity. [7] Method according to one of the preceding claims, characterized by that a moving average filter is used when filtering (S3) the determined values. [8] Method according to one of the preceding claims, characterized by that the filtering (S3) of the determined values is carried out cyclically. [9] Method according to one of the preceding claims, characterized by that the filtering (S3) of the determined values occurs when the second measured variable has a certain value. [10] Method for determining (S4) a control parameter as a function of a filtered first measured variable which is filtered using a method according to one of the preceding claims. [11] Computer device (6) which is arranged to carry out a method according to one of the preceding claims. [12] Vehicle (2) with a computer device (6) according to the preceding claim. [13] Vehicle (2) according to the preceding claim, characterized by that the vehicle (2) is a muscle-powered two-wheeler with a drive device (4), wherein the computer device (6) is designed to filter a first measured variable and, as a function thereof, to determine a control parameter in order to control the drive device (4) with the determined control parameter.

Images