Electric vehicle control method and electric vehicle control device

Abstract

The present invention includes: a basic torque allocation process for determining a basic torque command value for each drive motor on the basis of a total requested drive force for an electric vehicle and a drive force allocation for each drive system; a vibration control process for correcting each basic torque command value to suppress vibration of a drive force transmission system, so as to obtain corrected torque command values; and a drive force control process for controlling the drive force generated by each drive motor on the basis of the corrected torque command values. In the vibration control process, it is determined individually whether each drive system is in a dead zone, and in the drive systems in a dead zone, a correction amount for the basic torque command value is calibrated in accordance with the drive force allocation.

Description

[Technical Field]

[0001] The present invention relates to an electric vehicle control method and an electric vehicle control device. [Background technology]

[0002] WO2017 / 183231A1 discloses a control method for suppressing vibrations in a drive force transmission system of an electric vehicle that can be driven using torque from an electric motor, taking into account the transmission characteristics of a power transmission mechanism connected between the output shaft of the drive motor and the drive wheels. In particular, this control method estimates a dead zone in which drive motor torque is not transmitted to the drive shaft torque of the electric vehicle, and suppresses shocks caused by gear backlash by performing processing to speed up the response of the drive shaft torque in the dead zone. Summary of the Invention [Problem to be solved by the invention]

[0003] On the other hand, the inventors have noticed that in an electric vehicle having multiple drivetrains, each with its own drive motor, which drive different drive wheels, the timing at which gear backlash is eliminated varies for each drivetrain due to differences in the distribution of driving force between the drivetrains, which can result in variations in the length of the dead zone.For this reason, even if a conventional electric vehicle control method is applied to an electric vehicle having multiple drivetrains, the torque response performance of the electric vehicle in the dead zone varies depending on the driving state, which can cause discomfort to occupants.

[0004] Therefore, an object of the present invention is to provide an electric vehicle control method and an electric vehicle control device that can reduce the discomfort felt by occupants due to variations in the length of the dead zone sections of each drive system in an electric vehicle equipped with multiple drive motors. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided an electric vehicle control method for controlling the driving force of each drivetrain in an electric vehicle equipped with multiple drivetrains, each equipped with a drive motor. This electric vehicle control method includes a basic torque allocation process for determining a basic torque command value for each drivemotor based on a total required driving force for the electric vehicle and a driving force allocation to each drivetrain, a vibration suppression process for determining a corrected torque command value by correcting each basic torque command value to suppress vibration in the driving force transmission system, and a driving force control process for controlling the driving force generated by each drivemotor based on the corrected torque command value. The vibration suppression process individually estimates whether each drivetrain is in a dead zone, and for drivetrains in the dead zone, When a larger driving force is distributed to the drive system, the vibration compensation torque of the drive system becomes smaller. Adjust. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a block diagram illustrating the main configuration of an electric vehicle in which an electric vehicle control method according to each embodiment is executed. [Figure 2] FIG. 2 is a flowchart showing the flow of processing in the electric vehicle control method. [Figure 3] FIG. 3 is a diagram showing an example of an accelerator opening-torque table. [Figure 4] FIG. 4 is a block diagram illustrating the front and rear torque distribution process. [Figure 5] FIG. 5 is a block diagram illustrating the vibration suppression process according to the first embodiment. [Figure 6] FIG. 6 is a block diagram illustrating the F / F compensator of the front drive train according to the first embodiment. [Figure 7] FIG. 7 is a block diagram illustrating the F / F compensator of the rear drivetrain according to the first embodiment. [Figure 8] FIG. 8 is a diagram showing a model of a driving force transmission system of an electric vehicle (4WD). [Figure 9] FIG. 9 is a diagram illustrating the torque response characteristics of an electric vehicle. [Figure 10] FIG. 10 is a diagram showing a table of driving force distribution ratio and dead zone damping coefficient. [Figure 11] FIG. 11 shows the relationship between the front drive shaft torsional angular velocity F / B calculation unit and the driving force distribution ratio-dead band damping coefficient table. [Figure 12] FIG. 12 is a block diagram illustrating the F / B compensator of the front drive train according to the first embodiment. [Figure 13] FIG. 13 is a block diagram illustrating the F / B compensator of the rear drivetrain according to the first embodiment. [Figure 14] FIG. 14 is a block diagram illustrating the vibration suppression process according to the second embodiment. [Figure 15] FIG. 15 is a block diagram illustrating the configuration of the F / F compensator according to the second embodiment. [Figure 16] FIG. 16 is a time chart illustrating the control results of the electric vehicle control method of each embodiment. [Figure 17] FIG. 17 is a diagram showing a modified example of the configuration of an electric vehicle. [Figure 18] FIG. 18 is a diagram showing a modified example of the configuration of an electric vehicle. [Figure 19] FIG. 19 is a diagram showing a modified example of the configuration of an electric vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0008] [First embodiment] FIG. 1 is a block diagram illustrating the main configuration of an electric vehicle 100 for which an electric vehicle control method is implemented. In this embodiment, the electric vehicle 100 refers to a vehicle such as an electric vehicle (EV) or a hybrid vehicle (HEV) equipped with one or more electric motors (drive motors 4) as a driving source. In particular, the electric vehicle 100 of this embodiment includes a front drivetrain S including a drive motor 4 (front drive motor 4f) that applies driving force to the front drive wheels 9fR, 9fL. f and a rear drive system S including a drive motor 4 (rear drive motor 4r) that applies drive force to the rear drive wheels 9rR and 9rL. rIt is equipped with:

[0009] For the sake of simplicity, the following description will be limited to the front drivetrain S. f and rear drive system S r For each component in the f ,S r In other words, unless otherwise specified, the following description will refer to the front drivetrain S f and rear drive system S r This is common to each component of the

[0010] The battery 1 is configured as an on-board secondary battery that can supply (discharge) drive power when the drive motors 4f, 4r are in power running mode and can receive (charge) regenerated power when the drive motors 4f, 4r are in regenerative running mode.

[0011] The electric motor controller 2 receives the vehicle speed V, the accelerator opening APO, and the rotor phase α of the drive motors 4f and 4r. f ,α r , the motor current i which flows through the drive motors 4f and 4r f ,i r Signals indicating various vehicle variables such as the above are input as digital signals. The electric motor controller 2 generates PWM signals for controlling the drive motors 4f, 4r based on the input signals. The electric motor controller 2 also generates drive signals for the inverters 3f, 3r in response to the generated PWM signals.

[0012] The inverters 3f, 3r convert the DC current supplied from the battery 1 into AC by turning on / off two switching elements (e.g., power semiconductor elements such as IGBTs and MOS-FETs) provided for each phase, and pass the desired current through the drive motors 4f, 4r.

[0013] The drive motors 4f, 4r generate drive force using AC current supplied from the inverters 3f, 3r, and transmit the drive force to the drive wheels 9fR, 9fL, 9rR, and 9rL via a drive force transmission system consisting of the reducers 5f, 5r and the drive shafts Dsf, Dsr. The drive motors 4f, 4r also recover, as electrical energy, kinetic energy based on the regenerative braking force received from the drive wheels 9fR, 9fL, 9rR, and 9rL while the vehicle is running. In this case, the inverter 3 converts the AC current generated during regenerative operation of the drive motor 4 into DC current and supplies it to the battery 1. In particular, the front drive motor 4f supplies drive force to the front drive wheels 9fR and 9fL, and the rear drive motor 4r supplies drive force to the rear drive wheels 9rR and 9rL.

[0014] The current sensor 20 detects the motor current i f ,i r (Especially the front three-phase AC current i uf ,i vf ,i wf and rear three-phase AC current i ur ,i vr ,i wr ) is detected. However, the three-phase AC current i u ,i v ,i w Since the sum of these is 0, the currents of any two phases may be detected and the current of the remaining phase may be calculated.

[0015] The rotation sensor 21 is, for example, a resolver or an encoder, and detects the rotor phase α of the drive motors 4f and 4r. f ,α r Detect.

[0016] Fig. 2 is a flowchart showing each process in the electric vehicle control method programmed to be executed by the electric motor controller 2. The processes relating to steps S201 to S205 shown in Fig. 2 are repeatedly executed at a predetermined calculation cycle while the vehicle system is running.

[0017] In step S201, the electric motor controller 2 executes input processing. Specifically, the electric motor controller 2 receives signals indicating the various vehicle conditions described above as vehicle information. In particular, the signals indicating the vehicle conditions include the vehicle speed V (km / h), the accelerator opening APO (%), the rotor phase α f ,α r (rad), the motor rotation speed N mf ,N mr (rpm), motor current i f ,i r , and the DC voltage value V of battery 1 dc (V) and others.

[0018] The vehicle speed V (km / h) is acquired by communication from other controllers such as a meter or a brake controller. m (For example, front mechanical angular velocity ω mf and rear mechanical angular velocity ω mr Alternatively, the vehicle speed V (km / h) may be calculated by multiplying the tire rolling radius r by the tire rolling radius r and dividing by the gear ratio of the final gear to obtain the vehicle speed v (m / s), and then multiplying this by 3600 / 1000 to convert the unit.

[0019] The accelerator opening APO (%) is acquired from an accelerator opening sensor (not shown) or acquired through communication from another controller (not shown) such as a vehicle controller.

[0020] Rotor phase α f ,α r (rad) is acquired from the rotation sensor 21. The electric motor controller 2 controls the rotor phase α f ,α r The rotor angular velocity ω of each drive motor 4f, 4r is calculated by differentiating ef ,ω er (electrical angular velocity). The electric motor controller 2 also calculates the rotor angular velocity ω ef ,ω er is divided by the number of pole pairs p of the drive motors 4f and 4r to obtain the motor rotation angular velocity ωmf ,ω mr Furthermore, the electric motor controller 2 calculates the motor rotation angular velocity ω mf ,ω mr The motor rotation speed N is calculated by multiplying by the unit conversion coefficient (60 / 2π). mf ,N mr Calculate (rpm).

[0021] Motor current i f ,i r (A) is acquired from the current sensor 20. Also, the DC voltage value V dc (V) is detected by a voltage sensor (not shown) provided on the DC power supply line between the battery 1 and the inverter 3. The power supply voltage value obtained by a battery controller (not shown) is referred to as the DC voltage value V dc (V) may be obtained.

[0022] In step S202, the electric motor controller 2 executes a basic torque distribution process. Specifically, the electric motor controller 2 calculates the basic torque distribution based on the accelerator opening APO, the vehicle speed V, and the motor rotation speed N m Based on this, by referring to the accelerator opening-torque table shown in FIG. 3, the basic total torque command value T m * Set.

[0023] Furthermore, the electric motor controller 2 executes the front / rear torque distribution process shown in Fig. 4. Specifically, the electric motor controller 2 executes the basic total torque command value T m * Front distribution gain K f (0≦K f ≦1), the front drivetrain S f The front basic torque command value T corresponds to the target value of the driving force to be distributed to the mf * The electric motor controller 2 calculates the basic combined torque command value T m * Rear distribution gain (1-K f ) multiplied by the rear drivetrain Sr The rear basic torque command value T corresponds to the target value of the driving force to be distributed to mr * Ask for.

[0024] Next, in step S203, the electric motor controller 2 executes vibration damping processing. Specifically, the electric motor controller 2 performs vibration damping processing by adjusting the front basic torque command value T mf * By correcting the drive force transmission system vibration (such as torsional vibration of the front drive shaft Dsf) to mff * On the other hand, the electric motor controller 2 calculates the rear basic torque command value T mr * By performing vibration compensation calculations to suppress vibrations in the drive force transmission system (such as torsional vibrations of the rear drive shaft Dsr), the rear final torque command value T mrf * Details of the vibration suppression process will be described later.

[0025] In step S204, the electric motor controller 2 executes a current command value calculation process. Specifically, the electric motor controller 2 calculates the final torque command value T mff * ,T mrf * , each motor rotation angular velocity ω mf ,ω mr , and DC voltage value V dc Based on this, a predetermined table is referenced to determine the d-axis current target value i of each of the front drive motor 4f and the rear drive motor 4r. df * ,i dr * and q-axis current target value i qf * ,i qr * Ask for.

[0026] In step S205, the electric motor controller 2 executes current control calculation processing. Specifically, the electric motor controller 2 calculates the d-axis current idf and q-axis current i qf are the d-axis current target values ​​i df * and q-axis current target value i qf * and the d-axis current i of the rear drive motor 4r dr and q-axis current i qr are the d-axis current target values ​​i dr * and q-axis current target value i qr * Control is performed to match the

[0027] More specifically, the electric motor controller 2 controls the d-axis current target value i df * ,i dr * and q-axis current target value i qf * ,i qr * The PWM signals are generated based on the above-mentioned values, and the switching elements of the front inverter 3f and the rear inverter 3r are opened and closed by the PWM signals thus obtained, thereby driving the front drive motor 4f and the rear drive motor 4r with the desired torque.

[0028] The vibration suppression process S203 will be described in detail below.

[0029] 5 is a block diagram illustrating the vibration suppression process of this embodiment. In particular, the vibration suppression process S203 of this embodiment is f The configuration (top diagram of Figure 5) suppresses vibrations in the drivetrain transmission system, and the rear drivetrain S r In the following, for the sake of simplicity, the front drivetrain S f and rear drive system S r Each component in the above will be comprehensively described with its corresponding reference numeral.

[0030] As shown in the figure, the vibration suppression process S203 includes F / F compensators S501 and S503 and F / B compensators S502 and S504.

[0031] 6 and 7 are block diagrams illustrating the F / F compensators S501 and S503. As shown in the figures, the F / F compensators S501 and S503 have vehicle models S601 and S701 and torque correction units S602 and S702.

[0032] The vehicle models S601 and S701 are used to calculate the first torque command value T mf1 * ,T mr1 * Using a dead zone model that simulates the driving force characteristics of the electric vehicle 100 as an input, the torsional angular velocity estimate ω^ of the drive shafts Dsf and Dsr is calculated. df ,ω^ dr and the estimated twist angle θ^ df ,θ^ dr Here, the estimated torsional angular velocity ω^ is calculated. df ,ω^ dr is fed back to the torque correction units S602 and S702, and functions as an index for determining the amount of correction to suppress vibration in the torque correction units S602 and S702. df ,θ^ dr is fed back to the torque correction units S602 and S702, and f ,S r This serves as an index for determining whether the signal is in the dead zone.

[0033] In addition, the drive system S f ,S r The dead zone is the period when the backlash of the gears is reduced, and the output torque of the drive motors 4f and 4r (hereinafter referred to as "motor torque T mf ,T mr ") is the torque of the drive shafts Dsf and Dsr (hereinafter referred to as "drive shaft torque T df ,T dr In particular, the drivetrain S f ,S rThe dead zone of the front drive system S f and rear drive system S r Each of these is specified separately. f ,S r are in the dead zone (a state in which there is no torque response of the electric vehicle 100), will be referred to as the "dead zone of the electric vehicle 100" as appropriate.

[0034] The vehicle models S601 and S701 are configured to calculate the first torque command value T mf1 * ,T mr1 * Based on this, the motor rotation angular velocity ω mf ,ω m The estimated value of the motor rotation angular velocity ω^ mf ,ω^ mr ") is calculated and output to the F / B compensators S502 and S504.

[0035] The torque correction units S602 and S702 correct the basic torque command value T mf * ,T mr * , estimated twist angle θ^ df ,θ^ dr , and the estimated torsional angular velocity ω^ df ,ω^ dr is used as input, and the first torque command value T mf1 * ,T mr1 * Specifically, the torque correction units S602 and S702 calculate the torsional angular velocity estimated value ω^ df ,ω^ dr is multiplied by a predetermined feedback gain to obtain the vibration compensation torque ΔT mf ,ΔT mr Calculate the basic torque command value T mf * ,T mr * Vibration compensation torque ΔT mf ,ΔT mr is subtracted to obtain the first torque command value T mf1 * ,T mr1 * Calculate the following.

[0036] In particular, the torque correction units S602 and S702 calculate the torsion angle estimated value θ^ input from the vehicle models S601 and S701. df ,θ^ dr Depending on the reference result, the normal gain k f1 ,k r1 or dead band gain k f2 ,k r2 Vibration compensation torque ΔT mf ,ΔT mr More specifically, the torque correction units S602 and S702 calculate the torsion angle estimated value θ^ df ,θ^ dr If is not zero (drive system S f ,S r is estimated to be in a normal zone other than the dead zone), the estimated torsional angular velocity ω^ df ,ω^ dr Normal gain k f1 ,k r1 Multiplied by the vibration compensation torque ΔT mf ,ΔT mr On the other hand, the torque correction units S602 and S702 calculate the torsion angle estimated value θ^ df ,θ^ dr When is zero (drive system S f ,S r is estimated to be in the dead zone), the estimated torsional angular velocity ω^ df ,ω^ dr The dead band gain k f2 ,k r2 Multiplied by the vibration compensation torque ΔT mf ,ΔT mr Ask for.

[0037] The vehicle models S601 and S701 shown in FIGS. 6 and 7 will be described in detail.

[0038] 8 is a diagram showing a model of the driving force transmission system of electric vehicle 100. The definitions of each parameter, including those already explained, are shown below.

[0039] J mf ,J mr: Motor inertia J wf ,J wr : Drive wheel inertia (per axle) K df ,K dr : Torsional rigidity of the drive shaft K tf ,K tr : Coefficient of friction between the tire and road surface N f ,N r :Overall gear ratio r f ,r r : Tire load radius ω mf ,ω mr : Motor rotation angular velocity ω^ mf ,ω^ mr : Estimated motor rotation angular velocity θ mf ,θ mr : Motor rotation angle ω wf ,ω wr : Drive wheel angular velocity θ wf ,θ wr : Drive wheel angle T mf ,T mr :Motor torque T df ,T dr : Drive shaft torque F f ,F r : Driving force (for 2 axes) θ df ,θ dr :Twist angle of the drive shaft ω df ,ω dr : Torsional angular velocity of the drive shaft V: Vehicle speed M: Vehicle weight

[0040] From FIG. 8, the equations of motion of the 4WD electric vehicle 100 are expressed by the following equations (1) to (11).

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[0041] By Laplace transforming the above equations (1) to (11), the front motor torque T mf from the front motor rotation angular velocity ω mf The transfer characteristics up to are expressed by the following equations (12) and (13).

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[0042] In addition, the front motor torque T mfFront drive shaft torque T df The transfer characteristic up to is expressed by the following equation (15).

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[0043] From equations (3), (6), (8), and (10), the front motor rotational angular velocity ω mf from the front drive wheel angular velocity ω wf The transfer characteristic up to is expressed by the following equation (17).

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[0044] From equations (12), (13), and (17), the front motor torque T mf from the front drive wheel angular velocity ω wf The transfer characteristic up to is expressed by the following equation (18).

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[0045] From equations (15) and (18), the front drive shaft torque T df from the front drive wheel angular velocity ω wf The transfer characteristic up to is expressed by the following equation (19).

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[0046] Here, by transforming equation (1), the following equation (20) is obtained.

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[0047] Therefore, by using equations (19) and (20), the torsional angular velocity ω of the front drive shaft Dsf df can be expressed by the following equation (21).

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[0048] However, H in formula (21) wf (s) is determined by the following equation (22).

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[0049] Furthermore, v1, v0, w1, and w0 in equation (22) are determined by the following equation (23).

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[0050] Moreover, equation (15) can be transformed into the following equation (24).

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[0051] Here, "ζ" in equation (24) p ” is the damping coefficient of the torque transmission system of the front drive shaft Dsf, and ω p " is the natural vibration frequency of the torque transmission system of the front drive shaft Dsf.

[0052] Furthermore, since the pole α and the zero c0 / c1 of the transfer function expressed by equation (24) can be considered to be almost the same, the following equation (25) is obtained by performing pole-zero cancellation.

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[0053] Here, the front drivetrain S shown in Figure 6 f According to the control logic of the torque correction unit S602, the first torque command value T mf1 * is the front final torque command value T mff * The front final torque command value T mff * , the front basic torque command value T mf * and normal gain k f1 is expressed by the following equation (27).

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[0054] Then, the front final torque command value T mff * can be substituted as shown in the following equation (28) using equations (6) and (10).

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[0055] And T mf =T mff * By substituting equation (28) into equation (24), equation (29) can be obtained.

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[0056] Here, the front motor torque is converted to the front drive shaft torque T df The reference response up to is expressed by the following equation (30).

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[0057] The normal gain k for which equation (29) and equation (30) match f1The condition is expressed by the following equation (31).

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[0058] That is, the normal gain k f1 is the front motor torque T mf is the front drive shaft torque T df It is determined from the viewpoint of realizing the standard response in the normal section transmitted as

[0059] In addition, the dead band gain k f2 is determined by the following equation (32).

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[0060] That is, the front dead band gain k f2 is the front motor torque T mf is the front drive shaft torque T df In particular, the front deadband damping coefficient ζ is determined from the viewpoint of realizing a standard response in the deadband section where the damping coefficient is not sufficiently transmitted as γf is made smaller than the damping coefficient in the reference response of the normal section (in this embodiment, "1"), the dead band gain k f2 is the normal gain k f1 As a result, the front drivetrain S f When is in the dead zone, the front torsional angular velocity ω df and dead band gain k f2 Vibration compensation torque ΔT is determined by the product of mf (i.e., front basic torque command value T mf * Since the reduction correction amount for the torque is smaller, the torque response is faster than in the normal section.

[0061] Furthermore, in this embodiment, equations (1) to (23) are applied to calculate the front drivetrain S f A dead zone model is constructed that simulates the gear backlash characteristics in the front drive shaft torque T df is expressed by the following equation (33).

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[0062] Also, rear drive system S r Normal gain k r1 and dead band gain k r2 Regarding the front drive system S f Normal gain k f1 and dead band gain k f2 Using the same calculation logic as above, it can be obtained according to the following equations (34) and (35).

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[0063] Furthermore, rear drive system S r The rear drive shaft torque T is calculated by taking into account the dead zone model that simulates the gear backlash characteristics in dr Also, front drive system S f Using the same calculation logic, it can be expressed as the following equation (36).

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[0064] The front drivetrain S shown in the above equations (33) and (36) f and rear drive system S r The dead zone model is the dead zone block B shown in Fig. 6. df and the dead zone block B shown in Fig. 7 dr are realized by

[0065] Next, the dead band gain k f2 ,k r2 The specific method for determining this will be explained below.

[0066] In this embodiment, the drivetrain S100 that has a faster torque response when the entire drive force is distributed is selected. f ,S r The dead band gain k changes depending on the driving force distribution, while f2 ,k r2 This will be explained in more detail.

[0067] 9 is a diagram illustrating the torque response characteristics of the electric vehicle 100 of this embodiment. In particular, FIG. 9 shows the torque response characteristics of the front distribution gain K f When set to 1 (front drive system S f The solid lines show the time-dependent changes in each parameter (when all driving force is distributed to the front wheels), and the front distribution gain K f When set to 0 (rear drive system S r The broken lines show the time-dependent changes in each parameter (when all driving force is distributed to the m * , and Fig. 9(B) shows the front final torque command value T mff * , and Fig. 9(C) shows the rear final torque command value T mrf * 9(A) and FIG. 9(D) respectively show the longitudinal acceleration G of the electric vehicle 100.

[0068] First, the front drivetrain S f In the scene where the entire driving force is distributed to the front drive system S to transition from a deceleration state (front-rear acceleration G<0) to an acceleration state (front-rear acceleration G>0), fAt time t1, the vehicle enters the dead zone, and at time t2, the vehicle exits the dead zone and generates a torque response. r When the entire driving force is distributed to the front drivetrain S, the dead zone is entered at the same time t1, but the torque response occurs at time t3, which is later than time t2. f When all driving force is distributed to (K f =1) in the front drivetrain S f The time spent in the dead zone (t2-t1) is r When all driving force is distributed to (K f =0) in the rear drivetrain S r This is shorter than the time spent in the dead zone (t3-t1) of the front drivetrain S f and rear drive system S r Therefore, in this case, the torque response in the dead zone is faster when the full driving force is distributed to the front drivetrain S. f Based on the dead band gain k f2 ,k r2 The following is established.

[0069] Hereafter, the dead band gain k f2 ,k r2 The details of the mode of determining the above will be described.

[0070] Fig. 10 shows a driving force distribution ratio-dead zone damping coefficient table, and Fig. 11 shows the relationship between the front torque correction section S602 and the driving force distribution ratio-dead zone damping coefficient table.

[0071] As shown in Fig. 10, the front dead zone damping coefficient ζ γf Front drivetrain S f When all driving force is distributed to (K f = 1), which is the same as the damping coefficient of the reference response in the normal section (hereinafter also simply referred to as the "reference damping coefficient"). Therefore, in accordance with equation (32) shown in FIG. 11, the front dead band gain k f2 is the front normal gain k f1(Equation (31)). In other words, in this case, the front drivetrain S f Therefore, the electric vehicle 100 is in a state where it is driven solely by the front drivetrain S f This ensures torque response performance equivalent to that achieved when only the engine is installed.

[0072] In addition, the front drive system S f and rear drive system S r The driving force is distributed to both the front drivetrain and the rear drivetrain. f The area where the driving force distribution is relatively large (0.5 <K f <1), the front dead band damping coefficient ζ γf is the front distribution gain K f Even if the driving force is reduced, f = 1) to maintain the torque response performance of the front distribution gain K f On the other hand, the rear drivetrain S r Rear deadband damping coefficient ζ γr is maintained at the reference damping coefficient. f This can reduce variations in torque response characteristics caused by changes in the drive force distribution, thereby further improving the torque response performance of electric vehicle 100.

[0073] Furthermore, the front drive system S f Rear drivetrain S r The area where the driving force is large (0 <K f <0.5), the front deadband damping coefficient ζ γf is maintained at the reference damping coefficient. Meanwhile, the rear deadband damping coefficient ζ γr Rear drivetrain S r The fastest torque response is achieved when all driving force is distributed (K f =0) as the base point, 0.5 <K f Gain k for front deadband in the region <1 f2 The same decrease profile as the front distribution gain K f Increase in rear drive system S rIn other words, in this case, the rear drivetrain S r The torque response performance of the is independent of the driving force distribution, and is f = 0). This keeps the rear drivetrain S r This can reduce variations in torque response characteristics caused by changes in the drive force distribution, thereby further improving the torque response performance of electric vehicle 100.

[0074] The above explanation applies to the rear drivetrain S when all driving force is distributed. r The torque response in the dead zone of the front drivetrain S f When the rear drivetrain S is higher than r Based on the dead band gain k f2 ,k r2 This is also applicable to cases where

[0075] As described above, in this embodiment, the drivetrain S f ,S r Gain for dead band k f2 ,k r2 is the normal gain k r1 ,k r1 Therefore, the drivetrain S f ,S r Vibration compensation torque ΔT m (=k f ×ω d ) becomes smaller, and the torque response performance (the ability of the actual driving force to follow the total required driving force) of the electric vehicle 100 in the dead zone section improves. In addition, the front drivetrain S, which shows a faster torque response when the entire driving force is distributed, f Based on the dead band gain k f2 ,k r2 is determined, each drive system S f ,S r Regardless of the difference in the mechanical characteristics of the front drivetrain S, the torque response characteristics of the electric vehicle 100 in the dead zone section are f The characteristics can be made closer to those when only the rotor is used as a drive source.

[0076] Next, the F / B compensators S502 and S504 will be described in detail.

[0077] 12 and 13 are block diagrams showing the configurations of the F / B compensators S502 and S504. In particular, Fig. 12 shows the configuration of the front F / B compensator S502, and Fig. 13 shows the configuration of the rear F / B compensator S504.

[0078] As shown in the figure, the F / B compensators S502 and S504 have gain sections S5021 and S5041, filter sections S5022 and S5042, and filter sections S5023 and S5043.

[0079] The gain K used in the gain sections S5021 and S5041 is arranged to adjust the stability margin (gain margin, phase margin) of the feedback control system, and is set to a value of 1 or less.

[0080] The filter sections S5022 and S5042 are connected to the motor torque T mf ,T mr from the motor rotation angular velocity ω mf ,ω mr The filter has a transfer characteristic Gp(s) that simulates the transfer characteristic up to . The transfer characteristic Gp(s) is determined by, for example, the above equation (13).

[0081] The filter units S5023 and S5043 are filters called H(s) / Gp(s) that are composed of an inverse system of the transfer characteristic Gp(s) and a band-pass filter H(s). The band-pass filter H(s) has attenuation characteristics on the low-pass side and the high-pass side that are approximately the same, and has a torsional resonance frequency f p is set to be near the center of the passband on a logarithmic scale.

[0082] For example, when the bandpass filter H(s) is configured with a first-order highpass filter and a first-order lowpass filter, the bandpass filter H(s) is configured as shown in the following equation (37).

number

[0083] As a result, the F / B compensators S502 and S504 use the first torque command value T calculated by the vehicle models S601 and S701 of the F / F compensators S501 and S503. mf1 * ,T mr1 * Motor rotation angular velocity estimate ω^ based on mf ,ω^ mr and the second torque command value T before being multiplied by the gain K. mf2 * ,T mr2 * The estimated motor rotational angular velocity ω^ calculated by inputting the above into the transfer characteristic Gp(s) mf1 ,ω^ mr1 and are added to obtain the final motor rotation angular velocity estimate ω^ mff ,ω^ mrf Furthermore, the F / B compensators S502 and S504 calculate the final motor rotation angular velocity estimate ω^ mff ,ω^ mrf and the motor rotation angular velocity detection value ω obtained by the rotation sensor 21. mf_d ,ω mr_d The deviation from the second torque command value T is calculated by filtering the deviation with a filter H(s) / Gp(s) and multiplying it by a gain K. mf2 * ,T mr2 * Ask for.

[0084] As shown in FIG. 5, in the vibration suppression process S203, the final torque command value T mff* ,T mrf * is output from the F / F compensators S501 and S503 as the first torque command value T mf1 * ,T mr1 * and the second torque command value T output from the F / B compensators S502 and S504. mf2 * ,T mr2 * The operation is performed as the sum of

[0085] In this way, the final torque command value T mff * ,T mrf * is calculated, the first torque command value T after vibration compensation (feedforward compensation) by the F / F compensators S501 and S503 is calculated. mf1 * ,T mr1 * Further, the torque command value T mff * ,T mrf * As a result, each drive system S f ,S r Therefore, vibrations in the driving force transmission system can be more reliably suppressed.

[0086] The above-described configurations of this embodiment and the resulting effects will now be described.

[0087] In this embodiment, a plurality of drive systems S each having a drive motor 4f, 4r are provided. f ,S r In the electric vehicle 100 equipped with the f ,S r An electric vehicle control method for controlling a driving force of an electric vehicle is provided.

[0088] This electric vehicle control method is a method for controlling an electric vehicle 100 by controlling a total required driving force (basic total torque command value T m * ) and each drive system S f,S r Driving force distribution (K f or 1-K f ) based on the basic torque command value T mf * ,T mr * and the basic torque command value T mf * ,T mr * Correction is made to suppress vibration in the driving force transmission system to obtain the corrected torque command value (first torque command value T mf1 * ,T mr1 * or final torque command value T mff * ,T mrf * ) based on the corrected torque command value (more specifically, the final torque command value T mff * ,T mrf * The driving force (motor torque T mf ,T mr and a driving force control process (S204, S205) for controlling the driving force.

[0089] Then, in the vibration suppression process S203, each drive system S f ,S r is in the dead zone, and the drive system S f ,S r Then, the basic torque command value T mf * ,T mr * Correction amount (vibration compensation torque ΔT mf ,ΔT mr ) (see Figure 11).

[0090] This allows the basic torque command value T mf * ,T mr* Vibration compensation is performed on the final torque command value T mff * ,T mrf * Therefore, multiple drivetrains S f ,S r In an electric vehicle 100 equipped with the above, a control configuration is realized that reduces discomfort felt by occupants while maintaining vibration damping function.

[0091] In particular, in the vibration suppression process S203, each drive system S f ,S r Estimated torsional angular velocity ω^ of the drive shafts Dsf and Dsr at df ,ω^ dr to a given feedback gain (k f1 ,k f2 ,k r1 ,k r2 ) to obtain the vibration compensation torque ΔT mf ,ΔT mr Calculate the basic torque command value T mf * ,T mr * Vibration compensation torque ΔT mf ,ΔT mr is subtracted to obtain the corrected torque command value (first torque command value T mf1 * ,T mr1 * ) is calculated (torque correction section S602, S702). Then, the feedback gain in the normal section is calculated as the normal gain k f1 ,k r1 and the feedback gain in the dead band is set to the dead band gain k f2 ,k r2 Set to.

[0092] This allows each drive system S f ,S r A specific control logic is implemented for adjusting the torque response characteristics in the dead band section for each of the above cases.

[0093] Furthermore, in the vibration suppression process S203 of this embodiment, the dead zone gain kf2 ,k r2 Drive system S f ,S r However, the timing at which the dead zone is exited is determined to be approximately constant regardless of the drive force distribution.

[0094] This allows the time spent in the dead zone (either drive system S f , S r Therefore, the torque response performance of the electric vehicle 100 can be improved by shortening the period during which the torque does not contribute to the actual output driving force of the electric vehicle 100.

[0095] In addition, in the vibration suppression process S203 (especially the F / F compensators S501 and S503), each drive system S f ,S r Estimated torsional angular velocity ω^ of the drive shafts Dsf and Dsr df ,ω^ dr are calculated using vehicle models S601 and S701 that model the driving force transmission system of the electric vehicle 100.

[0096] This allows multiple drivetrains f ,S r Even when applying vibration damping processing to an electric vehicle 100 having a torsional angular velocity estimated value ω^ determined from a model corresponding to the actual electric vehicle 100, df ,ω^ dr By feedforward calculation based on f ,S r Vibration compensation torque ΔT that realizes optimal vibration suppression function mf ,ΔT mr Furthermore, in this embodiment, in the F / B compensators S502 and S504, the torsional angular velocity estimated values ​​ω^ based on the vehicle models S601 and S701 can be determined. df ,ω^ dr and the rotational angular velocity detection value ω of each motor mf_d ,ω mr_d The feedback vibration compensation torque (second torque command value T mf2 * ,T mr2 * ) is required, so multiple drivetrains Sf ,S r Even if the configuration is such that vibration suppression processing is performed on each torque command value (first torque command value T mf1 * ,T mr1 * ) can be appropriately removed from the vibration suppression compensation amount, and the accuracy of the vibration compensation can be ensured.

[0097] In addition, in the vibration suppression process S203 (especially the F / F compensators S501 and S503), the vehicle models S601 and S701 are used to calculate the vibration suppression coefficients of each drivetrain S f ,S r The estimated torsional angle θ^ of the drive shafts Dsf and Dsr at df ,θ^ dr We seek more.

[0098] This allows the same vehicle models S601 and S701 to be used together to calculate the vibration compensation torque ΔT mf ,ΔT mr The torsional angular velocity estimate ω^ used to calculate df ,ω^ dr and the torsion angle estimate θ^ used to estimate the dead zone df ,θ^ dr That is, the vibration compensation torque ΔT mf ,ΔT mr Since the parameters used for the calculation of and the estimation of the dead zone can be determined using the same vehicle model S601, S701, the control logic can be simplified and the calculation load can be reduced.

[0099] Furthermore, in this embodiment, each drive system S f ,S r Among these, drivetrain S distributes a relatively large driving force. f ,S r Gain for dead band k f2 ,k r2 The drive system S f ,S r The normal gain k is set when the value is outside the dead zone. f1 ,k r1 Set it smaller than

[0100] This distributes a relatively large driving force to the drivetrain S f ,S r Since the time spent in the dead zone of the drive train S is shortened, the torque response of the electric vehicle 100 can be made faster. In particular, even in a scene where the other drive trains are in the dead zone, the drive train S with the larger distributed drive force can be f ,S r The drivetrain S with a large distributed driving force can be made to quickly leave the dead zone and output a driving force closer to the total required driving force of the electric vehicle 100. f ,S r This makes it possible to obtain the same characteristics as when the electric vehicle 100 is driven solely by the motor.

[0101] In this embodiment, each drive system S f ,S r Gain for dead band k f2 ,k r2 The dead zone is the shortest when all the driving force is distributed to one drivetrain (for example, the front drivetrain S f ) dead band gain k f2 The drive system S f The normal gain k is set when the value is outside the dead zone. f1 Set it smaller than

[0102] As a result, the torque response timing of the electric vehicle 100 in the dead zone is adjusted to the front drivetrain S, which has a short dead zone due to its mechanical characteristics. f In other words, the torque response of the electric vehicle 100 can be made faster.

[0103] In addition to the electric vehicle control method, this embodiment provides an electric motor controller 2 that functions as an electric vehicle control device for executing this method. In particular, this electric motor controller 2 calculates the total required driving force for the electric vehicle 100 (basic total torque command value T m * ) and each drive system S f,S r Driving force distribution (K f or 1-K f ) based on the basic torque command value T mf * ,T mr * and a basic torque distribution unit (S202) that determines the basic torque command value T mf * ,T mr * Correction is made to suppress vibration in the driving force transmission system to obtain the corrected torque command value (first torque command value T mf1 * ,T mr1 * or final torque command value T mff * ,T mrf * ) based on the corrected torque command value (more specifically, the final torque command value T mff * ,T mrf * The driving force (motor torque T mf ,T mr The vibration suppression unit (S203) controls each drive system S f ,S r is in the dead zone, and the drive system S f ,S r Then, the basic torque command value T mf * ,T mr * Correction amount (vibration compensation torque ΔT mf ,ΔT mr ) (see Figure 11).

[0104] [Second embodiment] The second embodiment will be described below, with the same elements as those in the first embodiment being given the same reference numerals and their description omitted.

[0105] 14 is a block diagram illustrating the vibration suppression process S203 of this embodiment. In particular, in this embodiment, an F / F compensator S1201 is used instead of the F / F compensators S501 and S503 of the first embodiment.

[0106] 15 is a block diagram illustrating the configuration of the F / F compensator S1201. As shown in the figure, the F / F compensator S1201 is f and rear drive system S r The vehicle model S1301 is composed of each dead zone model that simulates the driving force characteristics of the front and rear wheels, and the front basic torque command value T mf * and the estimated front torsional angular velocity ω^ df to the front first torque command value T mf1 * and a front torque correction unit S1302 that calculates the rear basic torque command value T mr * and estimated rear torsional angular velocity ω^ dr to rear first torque command value T mr1 * and a rear torque correction unit S1303 that calculates the rear torque.

[0107] In addition, the front drive system S f Normal gain k f1 and dead band gain k f2 can be determined by the formulas (31) and (32) in the same manner as in the first embodiment. r Normal gain k r1 and dead band gain k r2 can also be determined by equations (34) and (35), respectively, in the same way as in the first embodiment.

[0108] Furthermore, each drive system S f , S r The backlash characteristics of the gears from the drive motors 4f, 4r to the drive shafts Dsf, Dsr in the first embodiment can also be determined from the equations (33) and (36), respectively, in the same manner as in the first embodiment.

[0109] Returning to FIG. 14, the vibration suppression process S203 includes F / B compensators S1202 and S1203 instead of the F / B compensators S502 and S504 of the first embodiment.

[0110] Here, the F / B compensator S1202 calculates the front motor rotational angular velocity estimate ω^ mf to the front motor rotation angular velocity detection value ω mf_d Subtract and apply bandpass filter H f (s) and front vehicle model G pf By multiplying the inverse model of (s), the second front torque command value T mf2 * Furthermore, the F / B compensator S1202 calculates the front first torque command value T mf1 * The second front torque command value T mf2 * By adding mff * Ask for.

[0111] On the other hand, the F / B compensator S1203 calculates the estimated rear motor rotational angular velocity ω^ mr to the rear motor rotation angular velocity detection value ω mr_d Subtract and apply bandpass filter H r (s) and vehicle model G pr By multiplying the inverse model of (s), the second rear torque command value T mr2 * Furthermore, the F / B compensator S1203 and the rear first torque command value T mr1 * The second rear torque command value T mr2 * By adding mrf * Ask for.

[0112] The electric vehicle control method according to this embodiment also achieves the same effects as those of the first embodiment.

[0113] [Control results according to this embodiment] 16 is a comparison diagram of the control results according to the first and second embodiments (examples) and the control results according to the reference example. m * , front final torque command value T mff * , rear final torque command value T mrf * , and longitudinal acceleration G, respectively. In each figure, the solid line, dashed line, and dotted line represent the front distribution gain K f The control results are shown for values ​​of 0.5, 0.7, and 1.0.

[0114] In addition, in FIG. 16, when the vehicle is decelerating due to the regenerative torque, the basic combined torque command value T m * The control results are shown for a scene where acceleration is achieved by increasing the torque at a gentle rate. In the reference example, the mechanical characteristics of the front and rear drivetrains are differentiated, and the vibration compensation torque ΔT mf ,ΔT mr On the other hand, in the example, the difference in the mechanical characteristics of the front and rear drive trains is the same as in the reference example, and the dead zone gains (particularly the front dead zone gain k f2 ) to set the

[0115] In the reference example, after the longitudinal acceleration G becomes 0 at time t1 and enters the dead zone, the same drive system (front drive system S in the figure) f Even with the same drive force distribution, the time spent in the dead zone (time t2 to t3) varies greatly depending on the drive force distribution. Furthermore, even with the same drive force distribution, the time spent in the dead zone differs between the front and rear drivetrains due to differences in mechanical characteristics.

[0116] In contrast, referring to the control results of the embodiment (solid line), the front drivetrain S f Regardless of the driving force distribution, the torque response timing is the timing when the full driving force is distributed (K f= 1.0) (time t2). As a result, the variation in the stagnation time in the dead zone (time t2 to t3) is eliminated. This is because the dead zone is estimated for each of the front and rear drive trains, and in the dead zone, the torsional angular velocity ω df ,ω dr This is due to the fact that the feedback gain multiplied by the is reduced. In particular, the front drivetrain S, which has a short dead zone due to its mechanical characteristics, f Based on the dead band gain k f2 By setting the above, the torque response timing (time t2) when the entire driving force is distributed is also advanced, so the time that the electric vehicle 100 remains in the dead zone is further shortened.

[0117] [Variations] The control logic relating to the electric vehicle control method explained in each of the above embodiments can also be applied to each vehicle having the system configuration shown in each of FIGS. 17 to 19 by making appropriate necessary modifications.

[0118] Specifically, the electric vehicle 200 shown in FIG. 17 does not have a drive system at the front, but has two rear drive systems, a first rear drive system SrR and a second rear drive system SrL.

[0119] The first rear drive system SrR has a first rear drive motor 4rR that drives the first rear drive wheel 9rR, and various sensors and actuators for controlling the first rear drive motor 4rR. The second rear drive system SrL has a second rear drive motor 4rL that drives the second rear drive wheel 9rL, and various sensors and actuators for controlling the second rear drive motor 4rL.

[0120] The electric vehicle 200 of this modified example can execute the electric vehicle control method of the present invention by, for example, replacing the parameters of the front drive system Sf and the rear drive system Sr in the above embodiment with parameters related to the first rear drive system SrR and the second rear drive system SrL, and making modifications such as setting a suitable vehicle model.

[0121] 18 includes a front drivetrain Sf, a first rear drivetrain SrR, and a second rear drive motor 4rL. That is, in this electric vehicle system 300, the drive motor 4 is made up of three motors: a front drive motor 4f that drives the front drive shaft Dsf, a first rear drive motor 4rR that drives the first rear drive wheel 9rR, and a second rear drive motor 4rL that drives the second rear drive wheel 9rL.

[0122] In the electric vehicle system 300 of this modified example, for example, while executing a control method similar to that of the above embodiment, the parameters set for the rear drivetrain Sr are distributed to the first rear drivetrain SrR and the second rear drivetrain SrL, thereby enabling the electric vehicle control method according to the present invention to be executed.

[0123] Furthermore, the electric vehicle 400 shown in FIG. 19 has a front drive system Sf that includes a first front drive system SfR equipped with various sensors and actuators for controlling a first front drive motor 4fR that drives a first front drive wheel 9fR, and a second front drive system SfL equipped with various sensors and actuators for controlling a second front drive motor 4fL that drives a second front drive wheel 9fL.

[0124] The rear drivetrain Sr is also made up of a first rear drivetrain SrR and a second rear drivetrain SrL. Therefore, the electric vehicle system 400 has four drive motors 4: a first front drive motor 4fR, a second front drive motor 4fL, a first rear drive motor 4rR, and a second rear drive motor 4rL.

[0125] In the electric vehicle system 400 of this modified example, for example, while executing a control method similar to that of the above embodiment, the parameters of the front drivetrain Sf are appropriately distributed to the first front drivetrain SfR and the second front drivetrain SfL, while the parameters of the rear drivetrain Sr are appropriately distributed to the first rear drivetrain SrR and the second rear drivetrain SrL, thereby making it possible to execute the electric vehicle control method according to the present invention.

[0126] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

Claims

1. An electric vehicle control method for controlling the driving force of each drive system in an electric vehicle equipped with a plurality of drive systems each having a drive motor, comprising: a basic torque distribution process for determining a basic torque command value for each of the drive motors based on a total required drive force for the electric vehicle and a drive force distribution for each of the drive trains; a vibration suppression process for correcting each of the basic torque command values ​​using a vibration compensation torque for suppressing vibration in the driving force transmission system to obtain a corrected torque command value; a driving force control process for controlling the driving forces generated by the respective driving motors based on the correction torque command values, In the vibration damping treatment, individually estimating whether each of the drive systems is in a dead zone; In the drive system in the dead band section, the vibration compensation torque of the drive system is adjusted to be smaller when a larger driving force is distributed to the drive system. Electric vehicle control method.

2. The electric vehicle control method according to claim 1, In the vibration damping treatment, calculating the vibration compensation torque by multiplying the estimated torsional angular velocity of the drive shaft in each of the drive systems by a predetermined feedback gain; The feedback gain in the dead-band section is set to a dead-band gain according to an increase or decrease in the driving force distribution. Electric vehicle control method.

3. 3. The electric vehicle control method according to claim 2, In the vibration damping treatment, The dead-band gain is determined so that the timing at which the drive system leaves the dead-band section is substantially constant regardless of the drive force distribution. Electric vehicle control method.

4. 4. The electric vehicle control method according to claim 2, In the vibration damping treatment, The torsional angular velocity estimated value used in calculating the vibration compensation torque is calculated using a vehicle model that models a driving force transmission system of the electric vehicle. Electric vehicle control method.

5. 5. The electric vehicle control method according to claim 4, In the vibration damping treatment, further obtaining an estimated torsion angle of a drive shaft in each of the drive trains using the vehicle model, and estimating whether or not each of the drive trains is in the dead zone by referring to the estimated torsion angle; Electric vehicle control method.

6. The electric vehicle control method according to any one of claims 2 to 5, The dead-band gain of the drive system to which a relatively large driving force is allocated is set to be smaller than the normal gain that is set when the drive system is in a section other than the dead-band section. Electric vehicle control method.

7. The electric vehicle control method according to any one of claims 2 to 5, Among the drive systems, the dead-band gain of one drive system having the characteristic that the dead-band interval is shortest when the entire drive force is distributed is set to be smaller than the normal gain that is set when the drive system is in an interval other than the dead-band interval. Electric vehicle control method.

8. An electric vehicle control device that controls the driving force of each drive system in an electric vehicle equipped with a plurality of drive systems each having a drive motor, a basic torque distribution unit that determines a basic torque command value for each of the drive motors based on a total required drive force for the electric vehicle and a drive force distribution for each of the drive trains; a vibration suppression unit that corrects each of the basic torque command values ​​using a vibration compensation torque that suppresses vibration in a driving force transmission system to obtain a corrected torque command value; a driving force control unit that controls the driving force generated by each of the driving motors based on the correction torque command value, The vibration damping unit is individually estimating whether each of the drive systems is in a dead zone; In the drive system in the dead band section, the vibration compensation torque of the drive system is adjusted to be smaller when a larger driving force is distributed to the drive system. Electric vehicle control device.

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