Driving force control method and driving force control device

Abstract

The present application sets either of an in-phase mode in which the positive and negative of the output torque of each motor are mutually consistent and an out-of-phase mode in which the positive and negative of the output torque of each motor are mutually different, as a control mode that determines the torque distribution of the vehicle, and performs distribution adjustment control that adjusts the torque distribution when the control mode is mutually switched between the in-phase mode and the out-of-phase mode, in which, during the idling period of the first output torque on the side on which the positive and negative are reversed at the time of the switching of the control mode, the second output torque on the side on which the positive and negative are not reversed is adjusted to be close to the total requested torque.

Description

Technical Field

[0001] This invention relates to a driving force control method and a driving force control device. Background Technology

[0002] JP2013-85375A proposes a drive force control device that controls the behavior of a vehicle body by separately controlling the drive forces of the front and rear wheels. In particular, this drive force control device controls the direction of the drive forces of the front and rear wheels to be reversed from the viewpoint of obtaining the desired pitch behavior of the vehicle body. One is for power operation (traction), and the other is for regeneration.

[0003] In particular, in this drive force control device, during the idling period before and after the positive and negative reversal of the output torque of one of the front wheel motors and the rear wheel motors (the period during which the phase delay of the drive transmission system, such as the backlash of the reducer, occurs and the drive force is not transmitted), the output torque of the other motor is kept constant.

[0004] According to the drive force control of JP2013-85375A, by keeping the output torque of one party constant during the idling period of the output torque of the other party, the total output torque of them is also kept constant, thus suppressing discomfort to the occupants.

[0005] However, if the total requested driving force (total requested torque) of the vehicle changes during the control period that includes the idling period in which the total output torque is set to a constant (in the case of vehicle acceleration or deceleration), at least during the idling period, a deviation occurs between the total requested torque and the total output torque, resulting in a step difference in the vehicle's front and rear acceleration. Summary of the Invention

[0006] Therefore, the purpose of this invention is to provide a driving force control method and driving force control device that can more reliably suppress the difference in front-to-rear acceleration when the output torque of one of the front wheel motors and the rear wheel motors reverses.

[0007] According to one aspect of the present invention, a drive force control method is provided to control the torque distribution of each electric motor so that the combined output torque of the front-wheel motor driving the front wheels and the rear-wheel motor driving the rear wheels meets the total requested torque of the vehicle. In this drive force control method, either a phase-in-phase mode where the output torques of each electric motor are of equal sign and a phase-out-of-phase mode where the output torques of each electric motor are of different signs is set as a control mode for determining the torque distribution. Furthermore, when switching between the phase-in-phase mode and the phase-out-of-phase mode, a distribution adjustment control is performed to adjust the torque distribution during the switching between the phase-in-phase mode and the phase-out-of-phase mode. In particular, in the distribution adjustment control, during the idling period of the first output torque (which is of opposite sign) when the control mode switches, the second output torque (which is of non-opposite sign) is adjusted to be close to the total requested torque. Attached Figure Description

[0008] Figure 1 This is a diagram illustrating the prerequisite structure of a vehicle for implementing the drive force control method according to various embodiments of the present invention.

[0009] Figure 2 This is a flowchart illustrating the distribution regulation control.

[0010] Figure 3 This is a timing diagram showing the control result of the allocation adjustment control in the first embodiment.

[0011] Figure 4A This is a graph illustrating the control results of the comparative example.

[0012] Figure 4B This is a diagram illustrating the effect of the control in the embodiment.

[0013] Figure 5 This is a timing diagram showing the control result of the allocation adjustment control in the second embodiment.

[0014] Figure 6 This is a timing diagram showing the control result of the allocation adjustment control in the third embodiment.

[0015] Figure 7 This is a timing diagram showing the control result of the allocation adjustment control in the fourth embodiment. Detailed Implementation

[0016] Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0017] [Prerequisite Structure]

[0018] Figure 1 This is a diagram illustrating the prerequisite structure of a vehicle 100 that implements the drive force control method of each embodiment.

[0019] In addition, as a vehicle 100, it is assumed that it is an electric vehicle or a hybrid vehicle, which is equipped with a drive motor 10 as a drive source and can drive using the driving force of the drive motor 10.

[0020] The drive motor 10 consists of a front wheel motor 10f that drives the front wheel 11f at a position in front of the vehicle 100 (front wheel side) and a rear wheel motor 10r that drives the rear wheel 11r at a position in the rear (rear wheel side).

[0021] The front wheel motor 10f is configured as a three-phase AC motor. During operation, the front wheel motor 10f receives power from an on-board battery (not shown) to generate driving force. The driving force generated by the front wheel motor 10f is transmitted to the front wheels 11f via the front wheel transmission 16f and the front wheel drive shaft 21f. Conversely, during regeneration, the front wheel motor 10f converts the regenerative braking force of the front wheels 11f into AC power and supplies it to the on-board battery.

[0022] On the other hand, the rear wheel motor 10r is configured as a three-phase AC motor. During operation, the rear wheel motor 10r receives power from the vehicle's battery to generate driving force. The driving force generated by the rear wheel motor 10r is transmitted to the rear wheels 11r via the rear wheel transmission 16r and the rear wheel drive shaft 21r. Furthermore, during regeneration, the rear wheel motor 10r converts the regenerative braking force of the rear wheels 11r into AC power and supplies it to the vehicle's battery.

[0023] The inverter 12 includes a front-wheel inverter 12f that regulates the power supply to the front-wheel motor 10f (positive during power operation and negative during regeneration) and a rear-wheel inverter 12r that regulates the power supply to the rear-wheel motor 10r (positive during power operation and negative during regeneration).

[0024] The front wheel inverter 12f regulates the power supply to the front wheel electric motor 10f to achieve a total requested torque T equivalent to the total driving force required by the vehicle 100. sum Corresponding front torque T f Additionally, the front torque T f This is the output torque of the front wheel motor 10f, which is equivalent to the driving force (or regenerative braking force) output by the front wheel motor 10f. On the other hand, the rear wheel inverter 12r regulates the power supply to the rear wheel motor 10r to achieve the same output torque as the total requested torque T. sum Corresponding rear torque T r Additionally, the rear torque T r It is the output torque of the rear wheel motor 10r, which is equivalent to the driving force (or regenerative braking force) output by the rear wheel motor 10r.

[0025] In particular, with the total requested torque T sum Corresponding front torque Tf and subsequent torque T r The torque distribution is determined to be essentially their sum (hereinafter also referred to as "total torque T"). f+r ") and total requested torque T sum Consistent. Additionally, the total requested torque T... sum For example, it can be determined based on the amount of operation of the accelerator pedal (accelerator opening APO) by the occupants of vehicle 100, or the instructions of ADAS (Advanced Driver Assistance Systems) or AD (Autonomous Driving).

[0026] Furthermore, a controller 50 for controlling the drive force distribution is provided in the vehicle 100. The controller 50 is composed of a computer equipped with a central processing unit (CPU), read-only memory (ROM), random access memory (RAM), and input / output interfaces (I / O interfaces), and is programmed to execute various processes in vehicle control as described below. In particular, the functions of the controller 50 can be implemented using any on-board computer such as a vehicle control module (VCM), a vehicle motion controller (VMC), and an electric motor controller, and / or a computer located outside the vehicle 100. Additionally, the controller 50 can be implemented using a single computer hardware unit or by distributing various processes across multiple computer hardware units.

[0027] Controller 50 will request the total torque T sum The detection results of various sensors (not shown) are used as input information to determine the front torque T corresponding to the desired torque distribution. f The command value (hereinafter also referred to as "pre-command torque T*") f ") and subsequent torque T r The command value (hereinafter referred to as "pre-command torque T*") r Then, the controller 50 sends commands to the front wheel inverter 12f and the rear wheel inverter 12r to make the front torque T... f The actual value (hereinafter, also referred to as "actual front torque T") f_re ") and rear torque T r The actual value (hereinafter, also referred to as "actual rear torque T") r_re ") Follow-up command torque T* f and the torque T* after the command r .

[0028] In particular, in the embodiments described later, the controller 50 will transfer the front torque T f and rear torque Tr The control mode that determines the torque distribution is set to either the in-phase mode where the positive and negative signals are consistent or the out-of-phase mode where the positive and negative signals are different.

[0029] In-phase mode is a control mode that specifies torque distribution to achieve desired vehicle characteristics during acceleration and deceleration. Specifically, in in-phase mode during acceleration, the front torque T... f and subsequent torque T r The distribution ratio κ is set within the range of 0 to 100:100 to 0, and is a basic distribution ratio (e.g., 50:50) to achieve the preferred vehicle characteristics during acceleration. On the other hand, in the in-phase mode during deceleration, the front torque T... f and subsequent torque T r The torque distribution ratio κ is set within the range of -100 to 0:0 to -100 as a basic distribution ratio (e.g., -50:-50) to achieve optimal vehicle characteristics during deceleration. Hereinafter, the torque distribution based on this basic distribution ratio to achieve optimal vehicle characteristics during acceleration or deceleration in in-phase mode is also referred to as "in-phase basic distribution". Furthermore, the basic distribution ratio in the in-phase basic distribution can be a fixed value or a variable value that varies within the aforementioned range.

[0030] Furthermore, the concept of vehicle characteristics envisioned in each embodiment includes, for example, characteristics related to the energy efficiency consumed by the vehicle 100 in actions such as driving (energy consumption rate performance), characteristics related to the difficulty of slippage of the front wheel 11f or the rear wheel 11r (slippage performance), and characteristics relative to the total requested torque T. sum The actual forward and backward acceleration tracking (dynamic performance), etc.

[0031] On the other hand, the out-of-phase mode is a control mode that specifies the torque distribution requested in control to achieve specific vehicle behavior based on various driving scenarios during vehicle 100 acceleration and deceleration. Furthermore, the control to achieve this specific vehicle behavior includes, for example, control to adjust the vehicle body pitch behavior by reducing vibrations transmitted to occupants when driving on steps or uneven surfaces (so-called pitch control), or control to improve the off-road capability of vehicle 100 when driving on special road surfaces. Additionally, the torque distribution based on the fundamental distribution ratio selected from the viewpoint of achieving the desired vehicle behavior in the out-of-phase mode during acceleration or deceleration is also referred to as "out-of-phase fundamental distribution".

[0032] In particular, the non-phase basic assignment includes front wheel regeneration assignment and rear wheel regeneration assignment corresponding to the target vehicle behavior.

[0033] In front wheel regeneration distribution, the commanded front torque T* f Setting it to a negative value will increase the torque T* after the command. rSet to a positive value. That is, while regenerating the front wheel motor 10f (while regenerating and braking the front wheel 11f), the rear wheel motor 10r is powered (driving the rear wheel 11r).

[0034] In the rear wheel regenerative distribution, the commanded front torque T* is distributed... f Set to a positive value, and set the torque T* after the command. r Set to a negative value. That is, while the front wheel motor 10f is running (while the front wheel 11f is running), the rear wheel motor 10r is regenerated (regenerative braking is applied to the rear wheel 11r).

[0035] In particular, in the drive force control methods of various embodiments, when switching the control mode between in-phase mode and out-of-phase mode, the actual front torque T is used to control the drive force. f_re Or actual rear torque T r_re During the idle period caused by backlash generated when one side crosses zero, the total torque T is suppressed. f+r Relative to the total requested torque T sum The distribution and adjustment control of the deviation. The following is an explanation of the distribution and adjustment control.

[0036] Furthermore, in this specification, "idling period" refers to the period during which, when the output torque of the motor reverses direction, the actual driving force transmitted to the drive wheels cannot adequately match the commanded value of the motor's output torque due to phase delays in the drive force transmission system from the motor to the drive wheels (e.g., backlash in the reduction gear). Hereinafter, specifically, the idling period arising from the drive force transmission system between the front wheel motor 10f and the front wheel 11f will be referred to as the "front idling period," and the idling period arising from the drive force transmission system between the rear wheel motor 10r and the rear wheel 11r will be referred to as the "rear idling period." Additionally, the aforementioned actual front torque T... f_re and actual rear torque T r_re These terms respectively refer to the torque equivalent to the driving force actually transmitted to the drive wheels via each driving force transmission system, and to the front wheel 11f and the rear wheel 11r.

[0037] [Distribution Adjustment Control]

[0038] Figure 2 This is a flowchart illustrating the control logic of the common allocation and adjustment control in various implementation methods. Furthermore, the controller 50 repeatedly executes the control logic according to each predetermined calculation cycle when the vehicle 100 accelerates or decelerates. Figure 2 The processes shown are as follows.

[0039] In step S110, the controller 50 determines whether a request has been generated to switch the control mode between out-of-phase and in-phase modes. For example, the controller 50 makes this determination based on input information obtained from various sensor types mounted on the vehicle 100 and / or a designated external server.

[0040] Next, in step S120, the controller 50 sets the torque adjustment start time. Specifically, the controller 50 determines an appropriate time to start the adjustment of the command torque before the idling period of one of the positive and negative sides of the torque.

[0041] Additionally, the following applies to adjusting the front torque T when switching control modes. f (Pre-command torque T*) f In the case of torque adjustment, the moment when the adjustment begins is also called the "pre-torque adjustment start time t". f_s On the other hand, after adjusting the torque T r (torque T* after command) r In the case of torque regulation starting, the moment when this adjustment begins is also called the "post-torque regulation start time t". r_s ".

[0042] Then, in step S130, the controller 50 sets the torque adjustment end time. Specifically, the controller 50 determines an appropriate time to end the torque adjustment after the idling period of one side of the torque reversal.

[0043] Additionally, the torque T* before the command is adjusted when switching control modes. f In this case, the moment when the adjustment ends is also called "the end of the pre-torque adjustment t". f_e On the other hand, after the adjustment command, the torque T* r In this case, the moment when the adjustment ends is also called "the end of the post-torque adjustment t". r_e ".

[0044] Then, in step S140, the controller 50 performs torque regulation. Specifically, from the regulation start time determined in step S120 until the regulation end time determined in step S130, the controller 50 switches the commanded torque from a value corresponding to the basic allocation of the control mode of the conversion source to a value closer to the total requested torque T. sum The value of .

[0045] Then, in step S150, the controller 50 ends the torque adjustment. Specifically, the controller 50 restores the commanded torque to the value corresponding to the basic allocation of the control mode for the switching target, using the aforementioned adjustment end time as a base point.

[0046] In the following implementation, for the Figure 2 The allocation adjustment control is illustrated with examples of its application in more specific scenarios.

[0047] [First Implementation Method]

[0048] In this embodiment, we will describe the distribution adjustment control applied to a scenario where, during vehicle acceleration to 100 km / h, the control mode transitions from a non-phase mode (front wheel regeneration and rear wheel power operation) to a phase mode (front wheel power operation and rear wheel power operation). Specifically, in this embodiment, the torque T before the corresponding control mode transition is adjusted. f In the case of reverse rotation from negative to positive, adjust the torque T* after the command during the forward idling period. r The allocation and adjustment control will be explained.

[0049] In particular, in this embodiment, Figure 2 In step S120, the rear torque adjustment starts at t r_s Determined as the torque T* before the command f (More specifically, the pre-command torque T* corresponding to the phase-differential basic allocation) f ) and the front torque threshold T f_th Consistent moments

[0050] Here, the front torque threshold T f_th As the moment before entering the pre-idle period (i.e., the commanded pre-torque T*) f Before the specified time (when it becomes zero), the torque T* before this command. f The achieved value is determined through experimentation or simulation. Specifically, the front torque threshold T... f_th It was determined that t was at the start of the rear torque adjustment. r_s During the period up to the moment of entering the pre-idle phase, the torque T* follows the adjusted command. r Actual rear torque T r_re The change becomes below the specified allowable upper limit. Additionally, the actual rear torque T... r_re The allowable upper limit for the variation is determined to be such that it will not cause the actual rear torque T to... r_re The degree to which the change in front-to-back acceleration (front-to-back G-change) causes discomfort to the occupants of vehicle 100.

[0051] In addition, in this embodiment, Figure 2 In step S130, when the rear torque adjustment is completed, t r_e The setting is consistent with the end time of the forward idling period (the moment of rotational swaying and blockage). Alternatively, the end time of the forward idling period can be determined in advance through experiments or simulations based on the characteristics of the drive force transmission system on the front wheel side of the vehicle 100.

[0052] Figure 3 This is a timing diagram illustrating an example of the control result of the allocation adjustment control in this embodiment.

[0053] As shown in the figure, after the moment t1 when the vehicle begins to accelerate to 100 km / h, the actual front torque T f_re and actual rear torque T r_re The command pre-torque T* corresponds to the basic phase distribution specified in the phase-shifting mode as the source of the phase transition. f (<0) and torque T* after command r (>0) and change.

[0054] Then, if the torque adjustment starts at t r_s Then, after the start command, the torque T* r The adjustment. Therefore, the actual rear torque T... r_re The entry timing gradually increases during the subsequent pre-idle phase to align with the total requested torque T. sum Consistent.

[0055] When entering the forward idling period, the control mode switches from the first out-of-phase mode to the same-phase mode. Subsequently, the commanded front torque T* is applied. f Maintain the basic distribution (more specifically, follow the switch from the out-of-phase basic distribution before the mode conversion to the in-phase basic distribution after the conversion). In contrast, the actual front torque T... f_re Due to the rotational wobbling caused by the phase delay in the transmission of driving force during the forward idling period, it cannot follow the commanded torque T*. f The change in torque was maintained at approximately zero. On the other hand, the actual rear torque T... r_re Follow-up torque adjustment starts at t r_s After the command for base point adjustment, the torque T* r The variation, from the entry time to the end time of the pre-idle period, is related to the total requested torque T. sum Consistent.

[0056] Then, when the end of the front idling period is reached (i.e., the end of the rear torque adjustment t), r_e When ), the torque T* after the command r Return the value corresponding to the basic allocation specified by the in-phase mode of the conversion target. Then, at time t2 after a certain time, the actual front torque T f_re and actual rear torque T r_re All converge to the stable basic distribution ratio in the in-phase mode during acceleration.

[0057] Next, the effect of the control described in this embodiment will be explained by comparing it with a comparative example.

[0058] Figure 4A This is a timing diagram illustrating the control results of the comparative example. Figure 4B This is a timing diagram illustrating the effects of the control in this embodiment. Additionally, Figure 4A The comparative example shown is conceived as maintaining control of the basic torque distribution specified in the first out-of-phase mode or in-phase mode during the entire control period (t = t1 ~ t2), including the pre-idle period (torque T* after command is not executed). r (Control of corrections).

[0059] like Figure 4A As shown, in the comparative example control, the actual front torque T f_re Torque T* before following the command f During the initial idling period when the torque is maintained at zero, the actual total torque T is generated. f+r_re The grade difference (the difference between the first and last G grades) (refer to the circled part in the figure).

[0060] In contrast, Figure 4B In the control of the illustrated embodiment, during the front idling period, the actual rear torque T r_re Following the revised command, the torque T* r And the total requested torque T sum It changes in a consistent manner. Therefore, it suppresses the G-level difference before and after the initial idling.

[0061] The structure and its effects in the above embodiment are summarized below.

[0062] In this embodiment, the torque distribution of each electric motor 10f and 10r is controlled to achieve the total output torque (total torque T) of the front wheel electric motor 10f driving the front wheel 11f of the vehicle 100 and the rear wheel electric motor 10r driving the rear wheel 11r. f+r To meet the total requested torque T of the vehicle (100). sum .

[0063] In this driving force control method, the output torque (front torque T) of each motor is set to 10f and 10r. f and subsequent torque T r This refers to either the in-phase mode where the positive and negative values ​​of the output torques of each motor (10f, 10r) are consistent, or the out-of-phase mode where the positive and negative values ​​of the output torques of each motor are different. In particular, in this drive force control method, when switching between the in-phase mode and the out-of-phase mode, a distribution adjustment control for adjusting the torque distribution is performed.

[0064] Furthermore, in this distribution regulation control, the first output torque (front torque T) of the side that reverses between positive and negative during control mode switching... f During the idling period (pre-idling period), the second output torque (rear torque T) of the non-reversible side is applied. r Adjust to be close to the total requested torque T sum .

[0065] Therefore, even in the front torque Tf During the freewheeling period when the front wheel 11f is not actually driven, the corrected torque T can also be used to transmit the torque. r Appropriately adjust the total torque T f+r Relative to the total requested torque T sum The deviation. As a result, even in the total requested torque T sum Even in scenarios involving changes and the period of forward idling, it can suppress unexpected forward and backward G-level differences, thus reducing the impact on the occupants.

[0066] Specifically, in this embodiment, the control mode is switched from out-of-phase mode to in-phase mode during vehicle 100 acceleration. In the distribution adjustment control, the adjusted torque T... r Command value (torque T* after command) r ), so that the rear torque T r Actual value (actual rear torque T) r_re ) and total requested torque T sum Consistent.

[0067] Thus, during the initial idling period, the total torque T is adjusted accordingly. f+r Relative to the total requested torque T sum More specific control logic for the deviation.

[0068] In addition, in this embodiment, the current torque T f Command value (torque T* before command) f ) and the specified torque threshold (front torque threshold T) f_th When they are consistent, the torque T* after the start command r The adjustment. Additionally, the torque T* is adjusted after the command ends, corresponding to the end of the forward idling period. r The adjustment.

[0069] Therefore, it is possible to achieve the actual rear torque T during the front idling period. r_re Appropriately follow the total requested torque T sum Furthermore, after the end of the pre-idle period, the torque distribution can be quickly returned to the basic distribution specified by the converted in-phase mode (torque distribution for achieving good vehicle characteristics).

[0070] Furthermore, in this embodiment, a controller 50 is provided that functions as a drive force control device for performing the above-described drive force control method.

[0071] Controller 50 controls the torque distribution of each electric motor 10f and 10r, so that the total output torque (total torque T) of the front wheel electric motor 10f driving the front wheel 11f of the vehicle 100 and the rear wheel electric motor 10r driving the rear wheel 11r is increased. f+r The total requested torque T of the vehicle is 100.sum .

[0072] Controller 50 sets the output torque (front torque T) of each motor at 10f and 10r. f and subsequent torque T r The controller 50 can switch between the in-phase mode and the out-of-phase mode, where the positive and negative values ​​of the output torques of the motors 10f and 10r are consistent. Furthermore, the controller 50 performs torque distribution adjustment control when switching between the in-phase and out-of-phase modes.

[0073] Then, in the distribution regulation control, the first output torque (front torque T) of the side that reverses between positive and negative when the control mode is switched is... f During the idling period (pre-idling period), the second output torque (rear torque T) of the non-reversible side is applied. r Adjust to be close to the total requested torque T sum .

[0074] Thus, a structure suitable for executing the aforementioned driving force control method was realized.

[0075] [Second Implementation]

[0076] The second embodiment will be described below. Furthermore, elements identical to those in the first embodiment are labeled with the same reference numerals, and their descriptions are omitted.

[0077] In the drive force control method of this embodiment, based on the distribution adjustment control described in the first embodiment, the commanded front torque T* is applied during the forward idle period. f An example of maintaining a zero torque command is provided.

[0078] exist Figure 5 The figure shows an example of the control result of the distribution adjustment control in this embodiment. As shown in the figure, in this embodiment, when the torque T* before the command is... f With respect to the specified threshold T for initiating malicious treatment f_th1 When (<0) is consistent, the controller 50 initiates a zero-torque command. Furthermore, corresponding to the initiation of the zero-torque command, the controller 50 also initiates the command-driven torque T* as described in the first embodiment. r The adjustment.

[0079] Additionally, the zero torque command will be executed due to the torque T* before the command. f The change in torque T* after the command r (Actual rear torque T) r_re Based on the view that the change in G converges within a range that will not cause discomfort to the occupants of the vehicle, the processing starts at the threshold T. f_th1 It was determined to be an appropriate value.

[0080] Additionally, when the torque T* before the command is given f With the specified processing end threshold T f_th2 When the zero torque command is met, controller 50 terminates the zero torque command. Furthermore, corresponding to the termination of the zero torque command, the torque T* after controller 50 terminates the command... r The adjustment is as follows. Furthermore, from the viewpoint of quickly returning the torque distribution after the zero-torque command ends to the basic distribution defined by the converted in-phase mode, the end threshold T is processed. f_th 2 was determined to be the appropriate value.

[0081] According to the driving force control method of this embodiment described above, the backlash G variation caused by tooth backlash during forward idling is suppressed by executing a zero torque command, and the torque T* is controlled by the command. r The adjustment makes the actual rear torque T r_re Appropriately follow the total requested torque T sum This suppresses the generation of G-level differences between the beginning and end.

[0082] Furthermore, since the torque T* after the start and end of the zero torque command corresponds to the start and end times of the zero torque command... r The adjustment allows the torque distribution to quickly return to the basic distribution of the vehicle's preferred characteristics (especially the basic distribution in in-phase mode) after a zero torque command.

[0083] [Third Implementation Method]

[0084] The third embodiment will now be described. Elements identical to those in the first or second embodiment are marked with the same symbols, and their descriptions are omitted. Specifically, in this embodiment, examples of applying distribution control will be described for scenarios where the control mode is switched first during vehicle 100 deceleration (hereinafter also referred to as "first half-stage switching") and scenarios where the control mode is switched subsequently (hereinafter also referred to as "second half-stage switching").

[0085] In particular, in this embodiment, during the first half of the deceleration transition, the control mode is changed from the same-phase mode (front wheels powered and rear wheels powered) to the opposite-phase mode (front wheels powered and rear wheels regenerated). On the other hand, during the second half of the transition, the control mode is changed from the opposite-phase mode (front wheels powered and rear wheels regenerated) to the same-phase mode (front wheels regenerated and rear wheels regenerated).

[0086] Figure 6 This illustrates an example of the control result of the allocation adjustment control in this embodiment. As shown in the figure, in the allocation adjustment control during the first half of the transition, the commanded torque T* during the subsequent idling period is... f Adjustment. Additionally, regarding the torque T* before the adjustment command.f The specific method, besides adjusting the object to replace the torque T, r And become the front torque T f Apart from this, the torque T* after the command is as described in the first embodiment. r The adjustment is the same.

[0087] On the other hand, in the distribution adjustment control during the second half of the transition, the commanded torque T* is applied during the initial idling period. r Adjustment. Additionally, regarding the torque T* after the adjustment command. r The specific method, besides the front torque T f Apart from the different direction of the sign conversion, the torque T* after the command described in the first embodiment is also different. r The adjustment is the same.

[0088] That is, in this embodiment, when the vehicle 100 decelerates, the first half of the conversion from the same-phase mode to the opposite-phase mode and the second half of the conversion from the opposite-phase mode to the same-phase mode are executed sequentially.

[0089] Then, in their respective distribution and adjustment controls, the command value of the second output torque is adjusted so that the actual value of the second output torque is close to the total requested torque T. sum Consistent. More specifically, in the distribution adjustment control during the first half of the transition, the adjustment command is given before the torque T*. f So that the actual front torque T during the rear idling period is f_re With total requested torque T sum Consistent. On the other hand, in the distribution adjustment control during the second half of the transition, the torque T* after the adjustment command. r To make the actual rear torque T during the front idling period r_re With total requested torque T sum Consistent.

[0090] Therefore, when the vehicle decelerates at 100 km / h during multiple control mode transitions, the actual front torque T can be achieved during the rear idling and front idling periods at each transition. f_re and actual rear torque T r_re With total requested torque T sum Appropriate consistency. As a result, even when the vehicle decelerates to 100 km / h, it is able to suppress unwanted front-to-rear G-level differences, reducing the impact on the occupants.

[0091] In particular, in this embodiment, during the distribution adjustment control in the latter half of the transition, the torque T* after the command is determined using the same control logic as in the first embodiment. r The start / end time of the adjustment, the torque T* after the command in the second half of the transition. rAfter adjustment, the torque distribution of vehicle 100 can be quickly restored to the basic distribution in the same direction mode of the switching target (achieving good vehicle performance distribution during deceleration).

[0092] [Fourth Implementation Method]

[0093] The fourth embodiment will now be described. Furthermore, elements identical to those in the first to third embodiments will be labeled with the same symbols, and their descriptions will be omitted.

[0094] In this embodiment, examples of executing the zero torque command described in the second embodiment in each scenario based on the allocation adjustment control performed in the first half-transition and the second half-transition as described in the third embodiment will be described.

[0095] Figure 7 This illustrates an example of the control result of the distribution adjustment control in this embodiment. As shown in the figure, in this embodiment, the torque T* after the command is set in the zero torque command during the first half of the transition. r Maintain zero torque. On the other hand, in the zero-torque command during the latter half of the transition, the torque T* before the command is... f The value remains zero. Furthermore, the specific control logic for the zero torque command (the start and end times and their relationship to the start and end times of each command torque) is the same as in the second embodiment.

[0096] In this way, by executing zero torque command and command torque adjustment respectively during the first half and second half of the deceleration of vehicle 100, the variation and level difference of front and rear G can be suppressed in both the first half and second half of the deceleration.

[0097] The embodiments of the present invention have been described above. However, the above embodiments are merely some examples of the application of the present invention and do not limit the technical scope of the present invention to the specific structures of the above embodiments.

[0098] In particular, the torque T* is determined after the start / end of the distribution adjustment control command. r Or the torque T* before the command f The specific control logic for the timing of the adjustment is not limited to the control logic shown in the above embodiments. It can also take into account the suppression effect of the G-level difference before and after the adjustment of the command torque and the balance between the two sides, which can be appropriately changed.

Claims

1. A driving force control method, comprising controlling the torque distribution of each electric motor such that the combined output torque of the front wheel motor driving the front wheels and the rear wheel motor driving the rear wheels meets the total requested torque of the vehicle, wherein, Either a synchronized in-phase mode where the output torques of each motor are of the same sign, or a non-synchronized out-of-phase mode where the output torques of each motor are of different signs, is set as the control mode for determining the torque distribution. The distribution adjustment control adjusts the torque distribution when the control mode switches between the in-phase mode and the out-of-phase mode. In the aforementioned distribution adjustment control, The entry and exit times of the idling period of the first output torque of the positive and negative sides during the control mode transition are determined. The entry time is the moment when the command value of the first output torque, corresponding to the basic torque distribution before the conversion, is zero. Set an adjustment start time that is earlier than the previously specified entry time. At least during the period from the start of the adjustment until the entry time, the commanded value of the first output torque is maintained at a value corresponding to the basic torque distribution before the conversion, while the commanded value of the second output torque (the non-reversible side) is switched from a value corresponding to the basic torque distribution before the conversion to a value close to the total requested torque. The command value of the second output torque after switching is determined in such a way that the actual value of the second output torque from the entry time to the end time is consistent with the total requested torque. The adjustment start time is determined in such a way that the change in the actual value of the second output torque during the period from the adjustment start time to the entry time is below the allowable upper limit for suppressing the change in the vehicle's front-rear acceleration during that period.

2. The driving force control method as described in claim 1, wherein, When the vehicle accelerates, the control mode is switched from the out-of-phase mode to the in-phase mode. In the aforementioned distribution adjustment control, The command value of the second output torque is adjusted so that the actual value of the second output torque during the idling period is consistent with the total requested torque.

3. The driving force control method as described in claim 1, wherein, During vehicle deceleration, the first half of the transition from the in-phase mode to the out-of-phase mode is executed sequentially, followed by the second half of the transition from the out-of-phase mode to the in-phase mode. The allocation adjustment control is performed in both the first half of the conversion and the second half of the conversion. In their respective allocation and adjustment controls Adjust the command value of the second output torque so that the actual value of the second output torque matches the total requested torque.

4. The driving force control method as described in claim 2 or 3, wherein, The adjustment start time is determined as the moment when the commanded value of the first output torque, which varies according to the basic torque distribution before the conversion, coincides with a predetermined torque threshold that is not zero. In the aforementioned distribution adjustment control, When the commanded value of the first output torque matches the predetermined torque threshold, the adjustment of the commanded value of the second output torque begins. The adjustment of the command value of the second output torque ends corresponding to the end of the idling period.

5. The driving force control method as described in claim 2 or 3, wherein, In the aforementioned distribution adjustment control, The first output torque command value is maintained at a value corresponding to the basic torque distribution before the conversion during the period from the start of the adjustment until the entry time, and the first output torque command value is maintained at zero during the idling period.

6. A drive force control device that controls the torque distribution of each electric motor so that the combined output torque of the front wheel motor driving the front wheels and the rear wheel motor driving the rear wheels meets the total requested torque of the vehicle, wherein, Either a synchronized in-phase mode where the output torques of each motor are of the same sign, or a non-synchronized out-of-phase mode where the output torques of each motor are of different signs, is set as the control mode for determining the torque distribution. The distribution adjustment control adjusts the torque distribution when the control mode switches between the in-phase mode and the out-of-phase mode. In the aforementioned distribution adjustment control, The entry and exit times of the idling period of the first output torque of the positive and negative sides during the control mode transition are determined. The entry time is the moment when the command value of the first output torque, corresponding to the basic torque distribution before the conversion, is zero. Set an adjustment start time that is earlier than the previously specified entry time. At least during the period from the start of the adjustment until the entry time, the commanded value of the first output torque is maintained at a value corresponding to the basic torque distribution before the conversion, while the commanded value of the second output torque (the non-reversible side) is switched from a value corresponding to the basic torque distribution before the conversion to a value close to the total requested torque. The command value of the second output torque after switching is determined in such a way that the actual value of the second output torque from the entry time to the end time is consistent with the total requested torque. The adjustment start time is determined in such a way that the change in the actual value of the second output torque during the period from the adjustment start time to the entry time is below the allowable upper limit for suppressing the change in the vehicle's front-rear acceleration during that period.

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