METHOD FOR OPERATING A MOBILE WORK MACHINE, COMPUTING UNIT AND MOBILE WORK MACHINE

Description

[0001] The present invention relates to a method for operating a mobile working machine, wherein the mobile working machine has a drive system with a transmission having at least two different selectable transmission levels, and a control element, e.g. a foot pedal, a computing unit and a computer program for its execution, as well as such a mobile working machine. Background of the invention

[0002] Mobile machinery, such as tractors or construction equipment, typically features a drive system with a transmission and a control element, such as a foot pedal. A traction force characteristic can be used to map the position of the control element to a traction force of the drive system in order to move the mobile machinery. Disclosure of the invention

[0003] According to the invention, a method for operating a mobile work machine, a computing unit and a computer program for its execution, as well as a mobile work machine with the features of the independent claims are proposed. Advantageous embodiments are the subject of the dependent claims and the following description.

[0004] The invention relates to mobile working machines such as tractors or construction machinery. Such a mobile working machine typically has a drive system with a transmission and a control element, such as a pedal, joystick, or the like. The drive system could be, for example, a hydrostatic or electric drive. The transmission can be a multi-stage transmission or comprise two or more stages. Generally, the transmission can have at least two different, selectable gear ratios (also referred to as gears). In practice, more than two gear ratios are also advantageous.

[0005] The two (or more) transmission stages can be implemented, for example, by using two (or more) hydraulic motors (within a hydrostatic drive). An example of such a hydrostatic drive with two transmission stages is described in DE 10 2020 210 196 A1 and can also be used here. However, the two (or more) transmission stages can also be implemented, for example, by using two (or more) mechanical gear stages (also within a hydrostatic drive); this is also known as "shift-on-fly". An example of this is described in EP 3 889 467 B1 and can also be used here.

[0006] The transmissions for such drive systems are typically used to provide appropriate torques for different driving situations (e.g., a gear or transmission stage with a high ratio for high torques at low speeds) and to meet requirements for the required speed range (e.g., a gear or transmission stage with a low ratio for maximum speed).

[0007] The torque to be supplied by the drive system can be predetermined by control (torque-based control) and implemented according to a drive concept. When shifting gears (changing the transmission stage), such a multi-stage transmission can be operated in a virtually torque-free manner – hydrostatically, for example, by pivoting the motor back, or in the case of electric drives, by reducing the torque at the motor or its inverter – in order to supply torque again after the new gear is engaged.

[0008] The required torque can be stored in the drive system software, for example, using tables or functions. This torque can depend on several factors, such as the position of the control element (e.g., the accelerator pedal position), the vehicle speed, the engine speed, and, most importantly, the currently engaged gear, i.e., the selected transmission ratio. In general, we will refer to these as tractive force functions, which map a control element position to a tractive force, i.e., a torque, that the drive system must deliver. This does not preclude the possibility that other factors may also be considered in a tractive force function. The term tractive force characteristic curve is also frequently used.

[0009] In particular, a tractive force function can also depend on the gear ratio; that is, each gear ratio can have its own tractive force function. Due to the dependence on the gear or gear ratio and its abrupt change during shifting, there is also a sharp jump in the stored data or tables (tractive force function) for the torque to be applied. This abrupt change, however, leads to acceleration or deceleration after the shift – which is often undesirable. Even a (simple) ramp or delayed application of the new torque would still cause a change in speed.

[0010] To circumvent this, it is possible, for example, to use only one traction force function for both (or several or all) gear ratios, possibly adjusted for the gear ratio between the gear ratios. However, this would result in either a low resolution of the control element and less precise control of the gear ratios, or the maximum speed would be unattainable.

[0011] Against this background, the use of a virtual control element position is proposed, which is used at least temporarily instead of a real control element position. Each of the two different, selectable transmission levels is assigned a traction force function that maps a control element position to a torque and / or speed of the mobile machine to be supplied by the drive system.

[0012] When a gear ratio change occurs from a previous gear ratio with a previous traction force function to a current (i.e., later) gear ratio with a current traction force function, a real control element position existing before the gear ratio change is provided or determined. Additionally, a speed of the mobile working machine existing before the change is provided or determined; furthermore, or alternatively to the speed, a torque to be applied based on the previous control element position and the previous traction force function before the change is provided or determined.

[0013] Based on the current traction force function, an equivalent value for the control element position is then determined such that the torque to be set, resulting from the virtual control element position and the current traction force function, corresponds at least within predefined limits to the torque to be set before the change, and / or such that the speed resulting from the equivalent value for the control element position and the current traction force function corresponds at least within predefined limits to the speed present before the change. The equivalent value can then be provided. In particular, the equivalent value can be determined such that the torque and / or speed are the same before and after the gear ratio change. This can usually be determined very easily using the traction force function.A vivid example of this will be explained in more detail in the character description.

[0014] In one embodiment, a virtual control position is determined, at least until one or more abort criteria are reached, based on the actual control position and taking into account the equivalent value of the control position. The drive system is then controlled according to the traction force function assigned to the currently selected transmission level and based on the virtual control position.

[0015] In this way, different traction force functions or characteristics can be used for different gear ratios, which can be optimally designed for the respective gear ratio as needed. By using the virtual control position, there is no change in speed when switching gear ratios if the user does not change the (real) control position.

[0016] In one embodiment, determining the virtual control position based on the real control position and taking into account the equivalent value of the control position involves defining or providing a transition function that maps the real control position to the virtual control position and includes the equivalent value of the control position. The virtual control position is then determined based on the real control position and the transition function. In this way, changes to the real control position after a translation stage change can also be mapped to a virtual control position or its change.

[0017] In one embodiment, the transition function is determined such that its value for the virtual control positions, starting from the equivalent value, approaches corresponding values ​​of an identity mapping as the value of the real control position increases and / or decreases; the identity mapping directly maps the real control position to the virtual control position. Furthermore, the transition function can be determined such that its range of values ​​for the real control positions, starting from the equivalent value, includes a maximum value for increasing and / or a minimum value for decreasing values ​​of the real control position. This allows for the highest possible resolution of the control element.

[0018] In one embodiment, a specific procedure is provided for each change in the direction of actuation of the control element. A change in the direction of actuation of the control element is understood to mean, in particular, that the control element is deflected more or less, i.e., that the user wants to decelerate or accelerate, for example. If the control element can be deflected between 0% and 100%, and if it is initially deflected by, for example, 50% during a gear ratio change, then increased to, for example, 75%, and then reduced again to, for example, 70%, a change in the direction of actuation of the control element occurs at 75%.

[0019] In such a case, a new equivalent value for the control position is determined, corresponding to the virtual control position when the direction of actuation changes. If the initial equivalent value for the transmission stage change was based on 50% for the actual control position, the new equivalent value in the example above is 75% for the actual control position. A new transition function is then also determined or provided, mapping the actual control position to the virtual control position and incorporating the new equivalent value. The virtual control position is then determined based on the actual control position and the new transition function. In this way, it is possible to continuously approximate the virtual control position more closely to the actual control position.This is especially true if the new transformation functions are determined in the same way as the initial transformation function, i.e., if they also approximate the identity mapping.

[0020] In one embodiment, after one or more of the abort criteria are reached, the drive system is controlled according to the traction force characteristic curve assigned to the currently selected transmission level and based on the actual control element position. In this way, regular operation is resumed. It should be noted that controlling the drive system based on the control element position is equivalent to controlling the drive system based on the virtual control element position, where the actual control element position is used as the virtual control element position.

[0021] Various criteria can be considered as abort criteria. For example, an abort criterion could be that the actual control position reaches a minimum or maximum value (i.e., 0% or 100%). In this case, the system can return to normal operation without any noticeable transition. Similarly, an abort criterion could be that the actual control position reaches a value that deviates from the minimum or maximum value by at most a predefined amount, e.g., 5% of the control's total deflection range (i.e., when 5% or 95% deflection is reached). This allows for an earlier return to normal operation in many cases.

[0022] Similarly, a termination criterion can be used, for example, that the virtual control position determined by the currently used transition function reaches a value that corresponds to the actual control position. In other words, this occurs when the transition function intersects the identity mapping or coincides with it from a certain point onward, and this point is reached. Similarly, a termination criterion can be used, for example, that the virtual control position determined by the currently used transition function reaches a value that deviates from the actual control position by at most a predefined value. In this way, a return to regular operation can be achieved earlier in many cases. Similarly, for example...A termination criterion can be used if the slope of the currently used transition function corresponds to a value or reaches a value that deviates from the slope of the identity mapping by at most a predefined value. In this way, a return to regular operation can also be achieved earlier in many cases.

[0023] In summary, the present invention proposes an algorithm that determines the torque requested prior to a gear or transmission stage change in the traction function of the newly engaged gear. To set the required torque in the new gear, a virtual control element position is calculated for the traction function of the new gear. Furthermore, the algorithm can include an additional part that continuously adjusts the virtual control element position to, for example, the actual control element position specified by the driver, until the actual control element position is again used to determine the traction function.

[0024] In this way, the driver can be provided with full control resolution in all situations, i.e., throughout the entire process. This means that with full control deflection, the maximum speed for the selected gear can be reached, and with zero deflection, deceleration to zero speed is possible without any noticeable abrupt change in traction. Setting the new traction or torque can be achieved by determining the initial ratio of the real vs. virtual control positions. As soon as a change in the control position is registered after the shift, the (remaining) resolution of the virtual control position is scaled to the remaining resolution of the real control position via a function. When the direction of movement of the control changes (e.g.,(After further pressing, the control element is released again.) The new point, determined by the ratio of the real to the virtual control element position, can be used as a new starting value to recalculate the scaling (real to virtual control element position). This can continue until certain conditions (termination criteria) allow the real control element position to be used again as a regular input for the traction force function.

[0025] A computing unit according to the invention, e.g. a control unit of a drive system of a mobile working machine, is, in particular in terms of programming, equipped to carry out a method according to the invention.

[0026] The invention also relates to a mobile working machine which has a drive with a transmission with at least two different, selectable transmission stages, and a control element, wherein the mobile working machine is configured to operate the drive with a currently selected transmission stage when the control element is actuated, and wherein the mobile working machine further comprises a computing unit according to the invention.

[0027] Implementing a method according to the invention in the form of a computer program or computer program product with program code for carrying out all method steps is also advantageous, as this incurs particularly low costs, especially if an executing control unit is already available for other tasks. Suitable data carriers for providing the computer program are, in particular, magnetic, optical, and electrical storage media, such as hard drives, flash memory, EEPROMs, DVDs, etc. Downloading a program via computer networks (Internet, intranet, etc.) is also possible.

[0028] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawing.

[0029] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified, but also in other combinations, as long as they do not contradict the claims.

[0030] The invention is schematically illustrated in the drawing using exemplary embodiments and is described in detail below with reference to the drawing. Character description

[0031] Figure 1 schematically shows a mobile work machine to illustrate the invention. Figure 2 schematically shows a process of a method according to the invention in one embodiment. Figure 3 shows diagrams to illustrate the invention. Detailed description of the drawing

[0032] In Figure 1A schematic diagram of a mobile work device 100 is shown to illustrate the invention. The mobile work device 100 is, by way of example, a tractor. The tractor 100 has a drive system 110, which, by way of example, comprises an electric machine or electric motor 112 and an inverter 114, a gearbox 116, and a computing unit 118 designed as a control unit for controlling the drive system 110. The tractor 100 also has a control element 120, by way of example, designed as a foot pedal.

[0033] The transmission 116 has, for example, two different selectable gear ratios, G1 and G2. The tractor 100 is configured so that when the accelerator pedal 120 is pressed, the drive unit 110 operates or is controlled by the currently selected gear ratio, G1 or G2, thus enabling the tractor 100 to move. The drive unit 110 can be controlled, in particular, by means of the control unit 118, which receives a signal from the accelerator pedal 120 indicating the current, actual position of the control element.

[0034] In Figure 2 A schematic flowchart illustrates the sequence of a method according to the invention in one embodiment. The following example demonstrates the sequence: Figure 2 as well as with reference to the diagrams of the Figure 3 will be explained in more detail.

[0035] In torque-based drive systems, for example, tractive force characteristics can be stored in the drive system software, e.g., via tables or functions. These tractive force characteristics can depend on several variables, such as the control element or accelerator pedal position, speed, and the like, especially the currently engaged gear or the selected transmission ratio. As mentioned above, the following discussion will refer generally to tractive force functions. As an example, tractive force functions for a two-gear transmission (transmission ratios) G1 and G2, which depend on speed and accelerator pedal position, will be used. The required torque (target torque) can be processed, for example, by drive system software (which is not further defined) and implemented at the drive system according to its architecture.This could be, for example, requesting a torque at the inverter of an electric drive system, or setting currents at valves of electrically controlled hydrostatic units.

[0036] When a transmission shift occurs during the operation or driving of the mobile work machine, from a previous transmission stage with a previous traction function to the current transmission stage with a current traction function, a virtual control element or accelerator pedal position is determined. The two transmission stages or gears will again be designated G1 and G2, and the corresponding traction functions ZF1 and ZF2. A real control element or accelerator pedal position will be designated FR, the virtual control element or accelerator pedal position FV, the speed v, and the torque to be set M.

[0037] As an example, let's consider a change from gear G1 to gear G2. In the case of a gear ratio change, step 200 determines or calculates the actual control element position FR prior to the change, the speed v of the mobile machine prior to the change, and the torque M to be applied prior to the change based on the previous control element position FR and the previous traction function ZF1.

[0038] The drive system uses the two gears G1 and G2 in conjunction with the associated traction functions ZF1 and ZF2 to create different speed ranges. This is in Figure 3Diagram (a) shows a speed v in km / h plotted against a real accelerator pedal position FR in %. Ideally, it is assumed that the traction force functions are designed so that the speed range is mapped linearly across the accelerator pedal position. Here, the speed range 0-18 km / h should be mapped via gear G1 and traction force function ZF1, and the speed range 0-40 km / h via gear G2 and traction force function ZF2. These ranges can depend on various factors and may be part of the vehicle / system design, which will not be discussed further here. It is understood that in practice, a non-linear mapping may be used.

[0039] For example, if a gear is changed during constant speed driving, the speed after the shift should be the same as before. If the actual accelerator pedal position (FR) remains constant during this shift, using two different traction force functions will result in a jump in the requested torque. This generally leads to the mobile work vehicle accelerating after upshifting and decelerating after downshifting, thus establishing a new speed.

[0040] If in diagram (a) Figure 3For example, if a value of 75% is given for the actual accelerator pedal position FR, this corresponds to a value of 13.5 km / h for the speed v in gear G1 (traction function ZF1); in gear G2 (traction function ZF2), however, this would correspond to a value of 30 km / h for the speed v. When changing from gear G1 to gear G2, the speed would therefore increase from approximately 13.5 km / h to 30 km / h with a constant accelerator pedal position (75%) and without any further functions.

[0041] To maintain speed after the gear change, the actual accelerator pedal position would have to be reduced from 75% to approximately 34%, as also shown in diagram (a) in Figure 3 to see.

[0042] In step 210, an equivalent value FA of the control element or accelerator pedal position is determined based on the current traction force function ZF2, such that the torque to be set, resulting from the equivalent value FA and the current traction force function ZF2, corresponds at least within predefined limits to the torque M to be set before the change. Similarly, this can be done such that the speed resulting from the equivalent value FA and the current traction force function ZF2 corresponds at least within predefined limits to the speed v present before the change.

[0043] This is also shown in diagram (a) in Figure 3This is also illustrated. As mentioned, a value of 75% for the actual accelerator pedal position FR in gear G1 (traction function ZF1) corresponds to a value of 13.5 km / h for the speed v. The value of 13.5 km / h for the speed v, in turn, corresponds to a value of approximately 34% for the actual accelerator pedal position FR in gear G2 (traction function ZF2). The accelerator pedal position is therefore a free parameter here, while the speed is predetermined. The new accelerator pedal position or value determined or calculated in this way is then referred to as the equivalent value FA ("equivalent accelerator pedal", see below). Figure 2 ) used.

[0044] In step 220, a virtual accelerator pedal position FV is determined based on the actual accelerator pedal position FR and taking into account the equivalent value FA. Based on this virtual accelerator pedal position FV, the drive system is then controlled in step 230 according to the traction force function ZF2 assigned to the currently selected transmission stage G2 and based on the virtual accelerator pedal position FV. This can include determining a torque to be applied (which may initially correspond to the previous value), as well as, in step 240, further implementation processes in the drive system software.

[0045] If, due to the independent design of the gears, the tractive force from the previous gear (previous gear ratio) cannot be found in the characteristic map or tractive force function of the newly engaged gear (current gear ratio), a value closest to the previous applied torque (tractive force) can be used. Furthermore, it is possible that the tractive force functions are not monotonically increasing at a given speed. This means that for a specific applied torque, two virtual accelerator pedal positions (or equivalent values) would be possible in the new gear at a given speed. In this case, the virtual accelerator pedal position (or equivalent value) that is closest to the actual accelerator pedal position can be selected.

[0046] Setting the new or old traction force (torque) using the virtual accelerator pedal position is only the first step. The primary goal is to allow the driver full accelerator pedal release after the gear change and to transition the virtual accelerator pedal position to the actual accelerator pedal position as smoothly as possible.

[0047] First, it can be assumed that no gear shift (transmission stage change) has been triggered recently. This means that the actual accelerator pedal position FR would be directly mapped to the virtual accelerator pedal position VF. In diagram (b) in Figure 3 The diagram shows the real accelerator pedal position FR plotted against the virtual accelerator pedal position FV. ID represents an identity mapping that directly maps the real accelerator pedal position FR to the virtual accelerator pedal position FV; this is, in particular, a straight line in the diagram passing through the origin.

[0048] If a shift is triggered, i.e., a change in gear ratio occurs, the actual accelerator pedal position FR is no longer used after the shift (or used or passed on for the virtual accelerator pedal position FV), but rather, initially, the equivalent value FA. The equivalent value FA from Figure 2 and how it is illustrated by diagram (a) in Figure 3 (arrows from value 75% for FR to value 34% for FR) results, is shown in diagram (b) in Figure 3 As shown, in this example upshift, the value of 75% for the actual accelerator pedal position in gear G1 corresponds to an equivalent value FA of 34% in gear G2. Therefore, a value of 34% is initially used as the virtual accelerator pedal position FV.

[0049] During operation, the actual accelerator pedal position can, of course, change; such a change must then also be reflected in the virtual accelerator pedal position. For this purpose, a transition function can be defined that maps the actual accelerator pedal position FR to the virtual accelerator pedal position FV and includes the equivalent value FA. The virtual accelerator pedal position is then determined based on the actual accelerator pedal position and the transition function.

[0050] In the diagram (b) in Figure 3UF1 and UF2 are two exemplary sections of such a transition function, where UF1 applies to increasing values ​​of the virtual accelerator pedal position and UF2 to decreasing values ​​of the virtual accelerator pedal position. In particular, to obtain full accelerator pedal resolution, the value ranges of the real accelerator pedal positions—here 0%–75% and 75%–100%—can be scaled or converted to value ranges of the virtual accelerator pedal positions—here 0%–34% and 34%–100%. This scaling can be represented by a predefined, parameterizable curve or function, but for the sake of simplicity, it will be assumed to be linear in the following explanation.

[0051] This linear scaling can be represented, for example, by connecting the equivalence value FA as the starting point with the respective endpoints of the identity mapping (at 100%, 100% and 0%, 0%). If the driver now moves their accelerator pedal after the gear shift, the virtual accelerator pedal position is scaled, i.e., changed, accordingly along the paths (transition function UF1, UF2). In other words, if the driver continues to depress the accelerator pedal (FR greater than 75%), the virtual accelerator pedal position FV is scaled along the path UF1. If the driver takes their foot off the accelerator pedal and reduces the real value (FR less than 75%), the virtual accelerator pedal position FV is scaled along the curve UF2.

[0052] If, for example, the driver sets an accelerator pedal value of 50% for the actual accelerator pedal position FR, the virtual accelerator pedal value for the virtual accelerator pedal position FV will be reduced accordingly to approximately 23%. As already mentioned, this scaling does not have to be linear, but can be progressive or converted using a different or other non-linear function.

[0053] When the driver reaches one of the endpoints Z (100%, 100%) and Y (0%, 0%) with the actual accelerator pedal, the lines of the scaling (transition function UF1, UF2) and the diagonal (identity mapping) intersect. In practice, the scaling can then be removed as a termination criterion, and the driver no longer moves along the transition function UF1, UF2, but only up and down along the diagonal (identity mapping). More precisely, this means that the actual accelerator pedal value is directly passed back into the traction force function as a virtual accelerator pedal value – which, as mentioned, is equivalent to the virtual accelerator pedal position no longer being used.

[0054] The points of intersection of the transition function UF1, UF2 or the relevant segments in the diagram with the diagonal (identity mapping) do not necessarily have to be exactly the endpoints; values ​​within the diagonal segment (identity mapping) can also be chosen, as in diagram (c). Figure 3 The intersection points (W) and (X) are shown here, along with the corresponding transition functions UF1' and UF2'. When the driver moves the real accelerator pedal away from 75%, the virtual accelerator pedal position can be scaled along the path or transition function UF1' and UF2' (shown here only linearly for simplicity).

[0055] As soon as the path transition function UF1', UF2' intersects the diagonal (identity mapping), i.e. at points W or X, it is also possible to resume only proceeding on the diagonal and to directly pass the real accelerator pedal value as a virtual accelerator pedal value into the traction force function.

[0056] Furthermore, it is possible that the driver, after depressing the accelerator pedal only a small amount further, then releases it and repeats this process. Therefore, in the scaling case according to diagram (b) or (c), he would never or only very rarely reach the endpoints Z,Y or possibly X,W, thus returning to the unscaled case.

[0057] Therefore, as soon as the direction of movement or actuation of the accelerator pedal changes, the value just reached can be used as a new equivalent value to scale to the endpoints Z, Y (or target points W, X). In diagram (d) of the Figure 3 This is illustrated. First, the equivalent value FA from diagram (b) is shown, as well as the transition function UF1 (here only for increasing values). The driver now increases the actual accelerator pedal value from 75% to 80%. At the value or new equivalent value FA' (here 80% of FR), the direction of movement or actuation of the accelerator pedal should change.

[0058] The actual accelerator pedal position FR is then reduced. A new scaling function or transition function UF2" with endpoint Y is then created from the new equivalent value FA') and the driver moves along the path of transition function UF2" when the accelerator pedal is reduced to 40%. At the value or new equivalent value FA" (here 40% of FR), the direction of movement or actuation of the accelerator pedal should change again. A subsequent increase in the accelerator pedal value then leads to endpoint Z along the path of transition function UF2".

[0059] The described procedure is for an upshift (from gear G1 to gear G2), but can be applied analogously to shifting to a lower gear (from gear G2 to gear G1). The equivalent values ​​shown in the figures would only apply below the diagonal ID.

[0060] For the aforementioned parameterizable curve or function, along which the ratio of real to virtual accelerator pedal position is scaled (transition function), an additional termination criterion can be introduced, in which the real accelerator pedal position is again passed one-to-one as virtual accelerator pedal position to the traction force function, or in which the virtual accelerator pedal position is no longer used ("normal operation").

[0061] Several transition possibilities, i.e., different termination criteria, are possible. This could, for example, be reaching the minimum or maximum value of the actual accelerator pedal position, i.e., reaching one of the endpoints Z, Y according to diagram (b) in Figure 3 As mentioned previously, it is possible to switch to normal operation if the accelerator pedal is either not pressed at all (point Y) or fully pressed (point Z). However, this sometimes leads to long "slow transition times," as it is quite possible that points Y or Z will only be reached after some time.

[0062] For this purpose, real accelerator pedal limits can be used. The system switches back to normal operation when the actual control position reaches a value that deviates from the minimum or maximum value by no more than a predefined amount. The transition to normal operation is therefore also possible via hard limits of the real accelerator pedal. For example, the conditions could be a real accelerator pedal value of < 5% or > 95%. If these limits are reached (exceeded / fall below), the system can switch directly back to normal operation. Points W and X in diagram (c) correspond, for example, approximately to real accelerator pedal values ​​of 10% and 90%. The advantage of this approach is that the limits are reached earlier than the actual endpoints, and also that for these limits it can be assumed that the driver actually desires (or at least expects) strong deceleration or acceleration, thus eliminating the need for a smooth transition.

[0063] It is also possible that the virtual accelerator pedal position, determined according to the currently used transition function, reaches a value that corresponds to the actual accelerator pedal position, i.e., when the transition function UF1',UF2' intersects the identity mapping ID (diagonal). This can be seen in diagram (c) with the points X,W. As soon as the diagonal is reached, normal operation can also be resumed.

[0064] It is also conceivable that the virtual accelerator pedal position, determined according to the currently used transition function, reaches a value that deviates from the actual accelerator pedal position by at most a predefined value; this is an absolute distance to the identity mapping ID (diagonal). This can be the case, for example, according to diagram (d), with the transition function UF2" halfway from FA" to Z.

[0065] This is also a possibility if the slope of the currently used transformation function corresponds to a value or reaches a value that deviates from the slope of the identity mapping ID by at most a predefined value. The diagonal has a slope (or scaling, translation) of one. If, for example, the method with linear lines is used, as in diagram (d) in Figure 3 As shown, the slope of the line will approach the value one with each change in accelerator pedal direction (from below or from above).

[0066] In the example shown in diagram (d), the slope from UF1, via UF2, to UF1 gradually approaches one (or, more generally, the slope of ID). If the slope of the scaling or transition function is close to a configurable value near one, the system also switches to normal operation. For example, a slope of less than 1.02 or greater than 0.98 could be used as a condition. For the case in diagram (d) in Figure 3 For example, the slope for UF1" could already be considered to be close to the slope of ID.

[0067] It is also possible to use a combination of the aforementioned termination criteria in order to utilize the advantages of each termination criterion simultaneously.

Claims

1. Method for operating a mobile working machine (100), wherein the mobile working machine has a traction drive (110) with a transmission (116) having at least two different, selectable transmission ratios (G1, G2), and an operating element (120), wherein the mobile working machine (100) is configured to operate the traction drive (110) at a currently selected transmission ratio when the operating element (120) is actuated, wherein each of the two different, selectable transmission ratios (G1, G2) is assigned in each case a traction force function which maps an operating element position of the operating element to a torque to be set by the traction drive and / or a speed of the mobile working machine, comprising, if a transmission ratio change from a previous transmission ratio with a previous traction force function to a current transmission ratio with a current traction force function takes place: providing or determining (200) a real operating element position (FR) present before the change, and a speed (v) of the mobile working machine present before the change, and / or a torque (M) to be set on the basis of the previous operating element position and the previous traction force function before the change; determining (210), on the basis of the current traction force function (ZF2), an equivalent value (FA) of the operating element position in such a way that the torque to be set that arises on the basis of the equivalent value (FA) and the current traction force function (ZF2) corresponds, at least within predefined limits, to the torque to be set that was present before the change, and / or in such a way that the speed resulting on the basis of the equivalent value and the current traction force function corresponds, at least within predefined limits, to the speed present before the change.

2. Method according to Claim 1, further comprising, at least until one or one of a plurality of termination criteria is reached: determining (220) a virtual operating element position on the basis of the real operating element position and taking into account the equivalent value of the operating element position; and controlling (230) the traction drive according to the traction force function assigned to the currently selected transmission ratio and on the basis of the virtual operating element position.

3. Method according to Claim 2, wherein the determination of the virtual operating element position (FV) on the basis of the real operating element position (FR) and taking into account the equivalent value (FA) of the operating element position comprises: determining or providing a transfer function (UF1, UF2) which maps the real operating element position to the virtual operating element position and comprises the equivalent value of the operating element position; and determining the virtual operating element position on the basis of the real operating element position and the transfer function.

4. Method according to Claim 3, furthermore comprising, in each case in the event of a change in an actuation direction of the operating element: determining a respective new equivalent value (FA', FA") of the operating element position which corresponds to the virtual operating element position when the actuation direction changes; determining or providing a respective new transfer function (UF1", UF2") that maps the real operating element position to the virtual operating element position and comprises the respective new equivalent value of the operating element position; and determining the virtual operating element position on the basis of the real operating element position and the respective new transfer function.

5. Method according to Claim 3 or 4, wherein the transfer functions are each determined such that their values of the virtual operating element positions, proceeding from the respective equivalent value, approach corresponding values of an identity map with an increasing and / or decreasing value of the real operating element position, wherein the identity map maps the real operating element position directly to the virtual operating element position.

6. Method according to one of Claims 3 to 5, wherein the transfer functions are each determined in such a way that their value ranges of the real operating element positions, proceeding from the respective equivalent value, comprise a maximum value for an increasing value and / or a minimum value for a decreasing value of the real operating element position.

7. Method according to one of Claims 2 to 6, wherein the equivalent value of the operating element position is used as the virtual operating element position immediately after the transmission ratio change.

8. Method according to one of Claims 2 to 7, further comprising, after reaching the one or the one of the plurality of termination criteria: controlling the traction drive in accordance with the traction force characteristic curve assigned to the currently selected transmission ratio and on the basis of the real operating element position.

9. Method according to one of Claims 2 to 8, wherein the one or more termination criteria comprise at least one of the following criteria: - the real operating element position reaches a minimum or maximum value, - the real operating element position reaches a value which deviates from the minimum or maximum value by at most a predefined value, - referring back to Claim 2 or 3: the virtual operating element position determined according to the currently used transfer function reaches a value which corresponds to the real operating element position, - referring back to Claim 2 or 3: the virtual operating element position determined according to the currently used transfer function reaches a value which deviates from the real operating element position by at most a predefined value, - referring back to Claim 4: a slope of the currently used transfer function corresponds to a value or reaches a value that deviates from a slope of the identity map by at most a predefined value.

10. Computing unit comprising a processor which is configured to carry out the steps of a method according to one of the preceding claims that are carried out by the computing unit.

11. Mobile working machine which has a traction drive with a transmission having at least two different, selectable transmission ratios, and an operating element, wherein the mobile working machine is configured to operate the traction drive at a currently selected transmission ratio when the operating element is actuated, wherein the mobile working machine furthermore has a computing unit according to Claim 10.

12. Computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method according to one of Claims 1 to 9.

13. Computer-readable data carrier on which the computer program according to Claim 12 is stored.